1// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
   2
   3/*
   4 * Common eBPF ELF object loading operations.
   5 *
   6 * Copyright (C) 2013-2015 Alexei Starovoitov <ast@kernel.org>
   7 * Copyright (C) 2015 Wang Nan <wangnan0@huawei.com>
   8 * Copyright (C) 2015 Huawei Inc.
   9 * Copyright (C) 2017 Nicira, Inc.
  10 * Copyright (C) 2019 Isovalent, Inc.
 
 
 
 
 
 
 
 
 
 
 
  11 */
  12
  13#ifndef _GNU_SOURCE
  14#define _GNU_SOURCE
  15#endif
  16#include <stdlib.h>
  17#include <stdio.h>
  18#include <stdarg.h>
  19#include <libgen.h>
  20#include <inttypes.h>
  21#include <limits.h>
  22#include <string.h>
  23#include <unistd.h>
  24#include <endian.h>
  25#include <fcntl.h>
  26#include <errno.h>
  27#include <ctype.h>
  28#include <asm/unistd.h>
  29#include <linux/err.h>
  30#include <linux/kernel.h>
  31#include <linux/bpf.h>
  32#include <linux/btf.h>
  33#include <linux/filter.h>
  34#include <linux/list.h>
  35#include <linux/limits.h>
  36#include <linux/perf_event.h>
  37#include <linux/ring_buffer.h>
  38#include <linux/version.h>
  39#include <sys/epoll.h>
  40#include <sys/ioctl.h>
  41#include <sys/mman.h>
  42#include <sys/stat.h>
  43#include <sys/types.h>
  44#include <sys/vfs.h>
  45#include <sys/utsname.h>
  46#include <sys/resource.h>
  47#include <tools/libc_compat.h>
  48#include <libelf.h>
  49#include <gelf.h>
  50#include <zlib.h>
  51
  52#include "libbpf.h"
  53#include "bpf.h"
  54#include "btf.h"
  55#include "str_error.h"
  56#include "libbpf_internal.h"
  57#include "hashmap.h"
  58
  59/* make sure libbpf doesn't use kernel-only integer typedefs */
  60#pragma GCC poison u8 u16 u32 u64 s8 s16 s32 s64
  61
  62#ifndef EM_BPF
  63#define EM_BPF 247
  64#endif
  65
  66#ifndef BPF_FS_MAGIC
  67#define BPF_FS_MAGIC		0xcafe4a11
  68#endif
  69
  70/* vsprintf() in __base_pr() uses nonliteral format string. It may break
  71 * compilation if user enables corresponding warning. Disable it explicitly.
  72 */
  73#pragma GCC diagnostic ignored "-Wformat-nonliteral"
  74
  75#define __printf(a, b)	__attribute__((format(printf, a, b)))
  76
  77static struct bpf_map *bpf_object__add_map(struct bpf_object *obj);
  78static struct bpf_program *bpf_object__find_prog_by_idx(struct bpf_object *obj,
  79							int idx);
  80static const struct btf_type *
  81skip_mods_and_typedefs(const struct btf *btf, __u32 id, __u32 *res_id);
  82
  83static int __base_pr(enum libbpf_print_level level, const char *format,
  84		     va_list args)
  85{
  86	if (level == LIBBPF_DEBUG)
  87		return 0;
  88
  89	return vfprintf(stderr, format, args);
 
 
 
  90}
  91
  92static libbpf_print_fn_t __libbpf_pr = __base_pr;
  93
  94libbpf_print_fn_t libbpf_set_print(libbpf_print_fn_t fn)
  95{
  96	libbpf_print_fn_t old_print_fn = __libbpf_pr;
  97
  98	__libbpf_pr = fn;
  99	return old_print_fn;
 
 
 
 
 
 
 
 
 
 
 
 
 
 100}
 101
 102__printf(2, 3)
 103void libbpf_print(enum libbpf_print_level level, const char *format, ...)
 104{
 105	va_list args;
 106
 107	if (!__libbpf_pr)
 108		return;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 109
 110	va_start(args, format);
 111	__libbpf_pr(level, format, args);
 112	va_end(args);
 113}
 114
 115static void pr_perm_msg(int err)
 116{
 117	struct rlimit limit;
 118	char buf[100];
 119
 120	if (err != -EPERM || geteuid() != 0)
 121		return;
 122
 123	err = getrlimit(RLIMIT_MEMLOCK, &limit);
 124	if (err)
 125		return;
 126
 127	if (limit.rlim_cur == RLIM_INFINITY)
 128		return;
 129
 130	if (limit.rlim_cur < 1024)
 131		snprintf(buf, sizeof(buf), "%zu bytes", (size_t)limit.rlim_cur);
 132	else if (limit.rlim_cur < 1024*1024)
 133		snprintf(buf, sizeof(buf), "%.1f KiB", (double)limit.rlim_cur / 1024);
 134	else
 135		snprintf(buf, sizeof(buf), "%.1f MiB", (double)limit.rlim_cur / (1024*1024));
 136
 137	pr_warn("permission error while running as root; try raising 'ulimit -l'? current value: %s\n",
 138		buf);
 
 139}
 140
 141#define STRERR_BUFSIZE  128
 
 
 
 
 
 142
 143/* Copied from tools/perf/util/util.h */
 144#ifndef zfree
 145# define zfree(ptr) ({ free(*ptr); *ptr = NULL; })
 146#endif
 147
 148#ifndef zclose
 149# define zclose(fd) ({			\
 150	int ___err = 0;			\
 151	if ((fd) >= 0)			\
 152		___err = close((fd));	\
 153	fd = -1;			\
 154	___err; })
 155#endif
 156
 157#ifdef HAVE_LIBELF_MMAP_SUPPORT
 158# define LIBBPF_ELF_C_READ_MMAP ELF_C_READ_MMAP
 159#else
 160# define LIBBPF_ELF_C_READ_MMAP ELF_C_READ
 161#endif
 162
 163static inline __u64 ptr_to_u64(const void *ptr)
 164{
 165	return (__u64) (unsigned long) ptr;
 166}
 167
 168struct bpf_capabilities {
 169	/* v4.14: kernel support for program & map names. */
 170	__u32 name:1;
 171	/* v5.2: kernel support for global data sections. */
 172	__u32 global_data:1;
 173	/* BTF_KIND_FUNC and BTF_KIND_FUNC_PROTO support */
 174	__u32 btf_func:1;
 175	/* BTF_KIND_VAR and BTF_KIND_DATASEC support */
 176	__u32 btf_datasec:1;
 177	/* BPF_F_MMAPABLE is supported for arrays */
 178	__u32 array_mmap:1;
 179	/* BTF_FUNC_GLOBAL is supported */
 180	__u32 btf_func_global:1;
 181	/* kernel support for expected_attach_type in BPF_PROG_LOAD */
 182	__u32 exp_attach_type:1;
 183};
 184
 185enum reloc_type {
 186	RELO_LD64,
 187	RELO_CALL,
 188	RELO_DATA,
 189	RELO_EXTERN,
 190};
 191
 192struct reloc_desc {
 193	enum reloc_type type;
 194	int insn_idx;
 195	int map_idx;
 196	int sym_off;
 197};
 198
 199struct bpf_sec_def;
 200
 201typedef struct bpf_link *(*attach_fn_t)(const struct bpf_sec_def *sec,
 202					struct bpf_program *prog);
 203
 204struct bpf_sec_def {
 205	const char *sec;
 206	size_t len;
 207	enum bpf_prog_type prog_type;
 208	enum bpf_attach_type expected_attach_type;
 209	bool is_exp_attach_type_optional;
 210	bool is_attachable;
 211	bool is_attach_btf;
 212	attach_fn_t attach_fn;
 213};
 214
 215/*
 216 * bpf_prog should be a better name but it has been used in
 217 * linux/filter.h.
 218 */
 219struct bpf_program {
 220	/* Index in elf obj file, for relocation use. */
 221	int idx;
 222	char *name;
 223	int prog_ifindex;
 224	char *section_name;
 225	const struct bpf_sec_def *sec_def;
 226	/* section_name with / replaced by _; makes recursive pinning
 227	 * in bpf_object__pin_programs easier
 228	 */
 229	char *pin_name;
 230	struct bpf_insn *insns;
 231	size_t insns_cnt, main_prog_cnt;
 232	enum bpf_prog_type type;
 233	bool load;
 234
 235	struct reloc_desc *reloc_desc;
 
 
 
 236	int nr_reloc;
 237	int log_level;
 238
 239	struct {
 240		int nr;
 241		int *fds;
 242	} instances;
 243	bpf_program_prep_t preprocessor;
 244
 245	struct bpf_object *obj;
 246	void *priv;
 247	bpf_program_clear_priv_t clear_priv;
 248
 249	enum bpf_attach_type expected_attach_type;
 250	__u32 attach_btf_id;
 251	__u32 attach_prog_fd;
 252	void *func_info;
 253	__u32 func_info_rec_size;
 254	__u32 func_info_cnt;
 255
 256	struct bpf_capabilities *caps;
 257
 258	void *line_info;
 259	__u32 line_info_rec_size;
 260	__u32 line_info_cnt;
 261	__u32 prog_flags;
 262};
 263
 264struct bpf_struct_ops {
 265	const char *tname;
 266	const struct btf_type *type;
 267	struct bpf_program **progs;
 268	__u32 *kern_func_off;
 269	/* e.g. struct tcp_congestion_ops in bpf_prog's btf format */
 270	void *data;
 271	/* e.g. struct bpf_struct_ops_tcp_congestion_ops in
 272	 *      btf_vmlinux's format.
 273	 * struct bpf_struct_ops_tcp_congestion_ops {
 274	 *	[... some other kernel fields ...]
 275	 *	struct tcp_congestion_ops data;
 276	 * }
 277	 * kern_vdata-size == sizeof(struct bpf_struct_ops_tcp_congestion_ops)
 278	 * bpf_map__init_kern_struct_ops() will populate the "kern_vdata"
 279	 * from "data".
 280	 */
 281	void *kern_vdata;
 282	__u32 type_id;
 283};
 284
 285#define DATA_SEC ".data"
 286#define BSS_SEC ".bss"
 287#define RODATA_SEC ".rodata"
 288#define KCONFIG_SEC ".kconfig"
 289#define KSYMS_SEC ".ksyms"
 290#define STRUCT_OPS_SEC ".struct_ops"
 291
 292enum libbpf_map_type {
 293	LIBBPF_MAP_UNSPEC,
 294	LIBBPF_MAP_DATA,
 295	LIBBPF_MAP_BSS,
 296	LIBBPF_MAP_RODATA,
 297	LIBBPF_MAP_KCONFIG,
 298};
 299
 300static const char * const libbpf_type_to_btf_name[] = {
 301	[LIBBPF_MAP_DATA]	= DATA_SEC,
 302	[LIBBPF_MAP_BSS]	= BSS_SEC,
 303	[LIBBPF_MAP_RODATA]	= RODATA_SEC,
 304	[LIBBPF_MAP_KCONFIG]	= KCONFIG_SEC,
 305};
 306
 307struct bpf_map {
 308	char *name;
 309	int fd;
 310	int sec_idx;
 311	size_t sec_offset;
 312	int map_ifindex;
 313	int inner_map_fd;
 314	struct bpf_map_def def;
 315	__u32 numa_node;
 316	__u32 btf_var_idx;
 317	__u32 btf_key_type_id;
 318	__u32 btf_value_type_id;
 319	__u32 btf_vmlinux_value_type_id;
 320	void *priv;
 321	bpf_map_clear_priv_t clear_priv;
 322	enum libbpf_map_type libbpf_type;
 323	void *mmaped;
 324	struct bpf_struct_ops *st_ops;
 325	struct bpf_map *inner_map;
 326	void **init_slots;
 327	int init_slots_sz;
 328	char *pin_path;
 329	bool pinned;
 330	bool reused;
 331};
 332
 333enum extern_type {
 334	EXT_UNKNOWN,
 335	EXT_KCFG,
 336	EXT_KSYM,
 337};
 338
 339enum kcfg_type {
 340	KCFG_UNKNOWN,
 341	KCFG_CHAR,
 342	KCFG_BOOL,
 343	KCFG_INT,
 344	KCFG_TRISTATE,
 345	KCFG_CHAR_ARR,
 346};
 347
 348struct extern_desc {
 349	enum extern_type type;
 350	int sym_idx;
 351	int btf_id;
 352	int sec_btf_id;
 353	const char *name;
 354	bool is_set;
 355	bool is_weak;
 356	union {
 357		struct {
 358			enum kcfg_type type;
 359			int sz;
 360			int align;
 361			int data_off;
 362			bool is_signed;
 363		} kcfg;
 364		struct {
 365			unsigned long long addr;
 366		} ksym;
 367	};
 368};
 369
 370static LIST_HEAD(bpf_objects_list);
 371
 372struct bpf_object {
 373	char name[BPF_OBJ_NAME_LEN];
 374	char license[64];
 375	__u32 kern_version;
 376
 377	struct bpf_program *programs;
 378	size_t nr_programs;
 379	struct bpf_map *maps;
 380	size_t nr_maps;
 381	size_t maps_cap;
 382
 383	char *kconfig;
 384	struct extern_desc *externs;
 385	int nr_extern;
 386	int kconfig_map_idx;
 387
 388	bool loaded;
 389	bool has_pseudo_calls;
 390
 391	/*
 392	 * Information when doing elf related work. Only valid if fd
 393	 * is valid.
 394	 */
 395	struct {
 396		int fd;
 397		const void *obj_buf;
 398		size_t obj_buf_sz;
 399		Elf *elf;
 400		GElf_Ehdr ehdr;
 401		Elf_Data *symbols;
 402		Elf_Data *data;
 403		Elf_Data *rodata;
 404		Elf_Data *bss;
 405		Elf_Data *st_ops_data;
 406		size_t strtabidx;
 407		struct {
 408			GElf_Shdr shdr;
 409			Elf_Data *data;
 410		} *reloc_sects;
 411		int nr_reloc_sects;
 412		int maps_shndx;
 413		int btf_maps_shndx;
 414		__u32 btf_maps_sec_btf_id;
 415		int text_shndx;
 416		int symbols_shndx;
 417		int data_shndx;
 418		int rodata_shndx;
 419		int bss_shndx;
 420		int st_ops_shndx;
 421	} efile;
 422	/*
 423	 * All loaded bpf_object is linked in a list, which is
 424	 * hidden to caller. bpf_objects__<func> handlers deal with
 425	 * all objects.
 426	 */
 427	struct list_head list;
 428
 429	struct btf *btf;
 430	/* Parse and load BTF vmlinux if any of the programs in the object need
 431	 * it at load time.
 432	 */
 433	struct btf *btf_vmlinux;
 434	struct btf_ext *btf_ext;
 435
 436	void *priv;
 437	bpf_object_clear_priv_t clear_priv;
 438
 439	struct bpf_capabilities caps;
 440
 441	char path[];
 442};
 443#define obj_elf_valid(o)	((o)->efile.elf)
 444
 445void bpf_program__unload(struct bpf_program *prog)
 446{
 447	int i;
 448
 449	if (!prog)
 450		return;
 451
 452	/*
 453	 * If the object is opened but the program was never loaded,
 454	 * it is possible that prog->instances.nr == -1.
 455	 */
 456	if (prog->instances.nr > 0) {
 457		for (i = 0; i < prog->instances.nr; i++)
 458			zclose(prog->instances.fds[i]);
 459	} else if (prog->instances.nr != -1) {
 460		pr_warn("Internal error: instances.nr is %d\n",
 461			prog->instances.nr);
 462	}
 463
 464	prog->instances.nr = -1;
 465	zfree(&prog->instances.fds);
 466
 467	zfree(&prog->func_info);
 468	zfree(&prog->line_info);
 469}
 470
 471static void bpf_program__exit(struct bpf_program *prog)
 472{
 473	if (!prog)
 474		return;
 475
 476	if (prog->clear_priv)
 477		prog->clear_priv(prog, prog->priv);
 478
 479	prog->priv = NULL;
 480	prog->clear_priv = NULL;
 481
 482	bpf_program__unload(prog);
 483	zfree(&prog->name);
 484	zfree(&prog->section_name);
 485	zfree(&prog->pin_name);
 486	zfree(&prog->insns);
 487	zfree(&prog->reloc_desc);
 488
 489	prog->nr_reloc = 0;
 490	prog->insns_cnt = 0;
 491	prog->idx = -1;
 492}
 493
 494static char *__bpf_program__pin_name(struct bpf_program *prog)
 495{
 496	char *name, *p;
 497
 498	name = p = strdup(prog->section_name);
 499	while ((p = strchr(p, '/')))
 500		*p = '_';
 501
 502	return name;
 503}
 504
 505static int
 506bpf_program__init(void *data, size_t size, char *section_name, int idx,
 507		  struct bpf_program *prog)
 508{
 509	const size_t bpf_insn_sz = sizeof(struct bpf_insn);
 510
 511	if (size == 0 || size % bpf_insn_sz) {
 512		pr_warn("corrupted section '%s', size: %zu\n",
 513			section_name, size);
 514		return -EINVAL;
 515	}
 516
 517	memset(prog, 0, sizeof(*prog));
 518
 519	prog->section_name = strdup(section_name);
 520	if (!prog->section_name) {
 521		pr_warn("failed to alloc name for prog under section(%d) %s\n",
 522			idx, section_name);
 523		goto errout;
 524	}
 525
 526	prog->pin_name = __bpf_program__pin_name(prog);
 527	if (!prog->pin_name) {
 528		pr_warn("failed to alloc pin name for prog under section(%d) %s\n",
 529			idx, section_name);
 530		goto errout;
 531	}
 532
 533	prog->insns = malloc(size);
 534	if (!prog->insns) {
 535		pr_warn("failed to alloc insns for prog under section %s\n",
 536			section_name);
 537		goto errout;
 538	}
 539	prog->insns_cnt = size / bpf_insn_sz;
 540	memcpy(prog->insns, data, size);
 
 541	prog->idx = idx;
 542	prog->instances.fds = NULL;
 543	prog->instances.nr = -1;
 544	prog->type = BPF_PROG_TYPE_UNSPEC;
 545	prog->load = true;
 546
 547	return 0;
 548errout:
 549	bpf_program__exit(prog);
 550	return -ENOMEM;
 551}
 552
 553static int
 554bpf_object__add_program(struct bpf_object *obj, void *data, size_t size,
 555			char *section_name, int idx)
 556{
 557	struct bpf_program prog, *progs;
 558	int nr_progs, err;
 559
 560	err = bpf_program__init(data, size, section_name, idx, &prog);
 561	if (err)
 562		return err;
 563
 564	prog.caps = &obj->caps;
 565	progs = obj->programs;
 566	nr_progs = obj->nr_programs;
 567
 568	progs = reallocarray(progs, nr_progs + 1, sizeof(progs[0]));
 569	if (!progs) {
 570		/*
 571		 * In this case the original obj->programs
 572		 * is still valid, so don't need special treat for
 573		 * bpf_close_object().
 574		 */
 575		pr_warn("failed to alloc a new program under section '%s'\n",
 576			section_name);
 577		bpf_program__exit(&prog);
 578		return -ENOMEM;
 579	}
 580
 581	pr_debug("found program %s\n", prog.section_name);
 582	obj->programs = progs;
 583	obj->nr_programs = nr_progs + 1;
 584	prog.obj = obj;
 585	progs[nr_progs] = prog;
 586	return 0;
 587}
 588
 589static int
 590bpf_object__init_prog_names(struct bpf_object *obj)
 591{
 592	Elf_Data *symbols = obj->efile.symbols;
 593	struct bpf_program *prog;
 594	size_t pi, si;
 595
 596	for (pi = 0; pi < obj->nr_programs; pi++) {
 597		const char *name = NULL;
 598
 599		prog = &obj->programs[pi];
 600
 601		for (si = 0; si < symbols->d_size / sizeof(GElf_Sym) && !name;
 602		     si++) {
 603			GElf_Sym sym;
 604
 605			if (!gelf_getsym(symbols, si, &sym))
 606				continue;
 607			if (sym.st_shndx != prog->idx)
 608				continue;
 609			if (GELF_ST_BIND(sym.st_info) != STB_GLOBAL)
 610				continue;
 611
 612			name = elf_strptr(obj->efile.elf,
 613					  obj->efile.strtabidx,
 614					  sym.st_name);
 615			if (!name) {
 616				pr_warn("failed to get sym name string for prog %s\n",
 617					prog->section_name);
 618				return -LIBBPF_ERRNO__LIBELF;
 619			}
 620		}
 621
 622		if (!name && prog->idx == obj->efile.text_shndx)
 623			name = ".text";
 624
 625		if (!name) {
 626			pr_warn("failed to find sym for prog %s\n",
 627				prog->section_name);
 628			return -EINVAL;
 629		}
 630
 631		prog->name = strdup(name);
 632		if (!prog->name) {
 633			pr_warn("failed to allocate memory for prog sym %s\n",
 634				name);
 635			return -ENOMEM;
 636		}
 637	}
 638
 639	return 0;
 640}
 641
 642static __u32 get_kernel_version(void)
 643{
 644	__u32 major, minor, patch;
 645	struct utsname info;
 646
 647	uname(&info);
 648	if (sscanf(info.release, "%u.%u.%u", &major, &minor, &patch) != 3)
 649		return 0;
 650	return KERNEL_VERSION(major, minor, patch);
 651}
 652
 653static const struct btf_member *
 654find_member_by_offset(const struct btf_type *t, __u32 bit_offset)
 655{
 656	struct btf_member *m;
 657	int i;
 658
 659	for (i = 0, m = btf_members(t); i < btf_vlen(t); i++, m++) {
 660		if (btf_member_bit_offset(t, i) == bit_offset)
 661			return m;
 662	}
 663
 664	return NULL;
 665}
 666
 667static const struct btf_member *
 668find_member_by_name(const struct btf *btf, const struct btf_type *t,
 669		    const char *name)
 670{
 671	struct btf_member *m;
 672	int i;
 673
 674	for (i = 0, m = btf_members(t); i < btf_vlen(t); i++, m++) {
 675		if (!strcmp(btf__name_by_offset(btf, m->name_off), name))
 676			return m;
 677	}
 678
 679	return NULL;
 680}
 681
 682#define STRUCT_OPS_VALUE_PREFIX "bpf_struct_ops_"
 683static int find_btf_by_prefix_kind(const struct btf *btf, const char *prefix,
 684				   const char *name, __u32 kind);
 685
 686static int
 687find_struct_ops_kern_types(const struct btf *btf, const char *tname,
 688			   const struct btf_type **type, __u32 *type_id,
 689			   const struct btf_type **vtype, __u32 *vtype_id,
 690			   const struct btf_member **data_member)
 691{
 692	const struct btf_type *kern_type, *kern_vtype;
 693	const struct btf_member *kern_data_member;
 694	__s32 kern_vtype_id, kern_type_id;
 695	__u32 i;
 696
 697	kern_type_id = btf__find_by_name_kind(btf, tname, BTF_KIND_STRUCT);
 698	if (kern_type_id < 0) {
 699		pr_warn("struct_ops init_kern: struct %s is not found in kernel BTF\n",
 700			tname);
 701		return kern_type_id;
 702	}
 703	kern_type = btf__type_by_id(btf, kern_type_id);
 704
 705	/* Find the corresponding "map_value" type that will be used
 706	 * in map_update(BPF_MAP_TYPE_STRUCT_OPS).  For example,
 707	 * find "struct bpf_struct_ops_tcp_congestion_ops" from the
 708	 * btf_vmlinux.
 709	 */
 710	kern_vtype_id = find_btf_by_prefix_kind(btf, STRUCT_OPS_VALUE_PREFIX,
 711						tname, BTF_KIND_STRUCT);
 712	if (kern_vtype_id < 0) {
 713		pr_warn("struct_ops init_kern: struct %s%s is not found in kernel BTF\n",
 714			STRUCT_OPS_VALUE_PREFIX, tname);
 715		return kern_vtype_id;
 716	}
 717	kern_vtype = btf__type_by_id(btf, kern_vtype_id);
 718
 719	/* Find "struct tcp_congestion_ops" from
 720	 * struct bpf_struct_ops_tcp_congestion_ops {
 721	 *	[ ... ]
 722	 *	struct tcp_congestion_ops data;
 723	 * }
 724	 */
 725	kern_data_member = btf_members(kern_vtype);
 726	for (i = 0; i < btf_vlen(kern_vtype); i++, kern_data_member++) {
 727		if (kern_data_member->type == kern_type_id)
 728			break;
 729	}
 730	if (i == btf_vlen(kern_vtype)) {
 731		pr_warn("struct_ops init_kern: struct %s data is not found in struct %s%s\n",
 732			tname, STRUCT_OPS_VALUE_PREFIX, tname);
 733		return -EINVAL;
 734	}
 735
 736	*type = kern_type;
 737	*type_id = kern_type_id;
 738	*vtype = kern_vtype;
 739	*vtype_id = kern_vtype_id;
 740	*data_member = kern_data_member;
 741
 742	return 0;
 743}
 744
 745static bool bpf_map__is_struct_ops(const struct bpf_map *map)
 746{
 747	return map->def.type == BPF_MAP_TYPE_STRUCT_OPS;
 748}
 749
 750/* Init the map's fields that depend on kern_btf */
 751static int bpf_map__init_kern_struct_ops(struct bpf_map *map,
 752					 const struct btf *btf,
 753					 const struct btf *kern_btf)
 754{
 755	const struct btf_member *member, *kern_member, *kern_data_member;
 756	const struct btf_type *type, *kern_type, *kern_vtype;
 757	__u32 i, kern_type_id, kern_vtype_id, kern_data_off;
 758	struct bpf_struct_ops *st_ops;
 759	void *data, *kern_data;
 760	const char *tname;
 761	int err;
 762
 763	st_ops = map->st_ops;
 764	type = st_ops->type;
 765	tname = st_ops->tname;
 766	err = find_struct_ops_kern_types(kern_btf, tname,
 767					 &kern_type, &kern_type_id,
 768					 &kern_vtype, &kern_vtype_id,
 769					 &kern_data_member);
 770	if (err)
 771		return err;
 772
 773	pr_debug("struct_ops init_kern %s: type_id:%u kern_type_id:%u kern_vtype_id:%u\n",
 774		 map->name, st_ops->type_id, kern_type_id, kern_vtype_id);
 775
 776	map->def.value_size = kern_vtype->size;
 777	map->btf_vmlinux_value_type_id = kern_vtype_id;
 778
 779	st_ops->kern_vdata = calloc(1, kern_vtype->size);
 780	if (!st_ops->kern_vdata)
 781		return -ENOMEM;
 782
 783	data = st_ops->data;
 784	kern_data_off = kern_data_member->offset / 8;
 785	kern_data = st_ops->kern_vdata + kern_data_off;
 786
 787	member = btf_members(type);
 788	for (i = 0; i < btf_vlen(type); i++, member++) {
 789		const struct btf_type *mtype, *kern_mtype;
 790		__u32 mtype_id, kern_mtype_id;
 791		void *mdata, *kern_mdata;
 792		__s64 msize, kern_msize;
 793		__u32 moff, kern_moff;
 794		__u32 kern_member_idx;
 795		const char *mname;
 796
 797		mname = btf__name_by_offset(btf, member->name_off);
 798		kern_member = find_member_by_name(kern_btf, kern_type, mname);
 799		if (!kern_member) {
 800			pr_warn("struct_ops init_kern %s: Cannot find member %s in kernel BTF\n",
 801				map->name, mname);
 802			return -ENOTSUP;
 803		}
 804
 805		kern_member_idx = kern_member - btf_members(kern_type);
 806		if (btf_member_bitfield_size(type, i) ||
 807		    btf_member_bitfield_size(kern_type, kern_member_idx)) {
 808			pr_warn("struct_ops init_kern %s: bitfield %s is not supported\n",
 809				map->name, mname);
 810			return -ENOTSUP;
 811		}
 812
 813		moff = member->offset / 8;
 814		kern_moff = kern_member->offset / 8;
 815
 816		mdata = data + moff;
 817		kern_mdata = kern_data + kern_moff;
 818
 819		mtype = skip_mods_and_typedefs(btf, member->type, &mtype_id);
 820		kern_mtype = skip_mods_and_typedefs(kern_btf, kern_member->type,
 821						    &kern_mtype_id);
 822		if (BTF_INFO_KIND(mtype->info) !=
 823		    BTF_INFO_KIND(kern_mtype->info)) {
 824			pr_warn("struct_ops init_kern %s: Unmatched member type %s %u != %u(kernel)\n",
 825				map->name, mname, BTF_INFO_KIND(mtype->info),
 826				BTF_INFO_KIND(kern_mtype->info));
 827			return -ENOTSUP;
 828		}
 829
 830		if (btf_is_ptr(mtype)) {
 831			struct bpf_program *prog;
 832
 833			mtype = skip_mods_and_typedefs(btf, mtype->type, &mtype_id);
 834			kern_mtype = skip_mods_and_typedefs(kern_btf,
 835							    kern_mtype->type,
 836							    &kern_mtype_id);
 837			if (!btf_is_func_proto(mtype) ||
 838			    !btf_is_func_proto(kern_mtype)) {
 839				pr_warn("struct_ops init_kern %s: non func ptr %s is not supported\n",
 840					map->name, mname);
 841				return -ENOTSUP;
 842			}
 843
 844			prog = st_ops->progs[i];
 845			if (!prog) {
 846				pr_debug("struct_ops init_kern %s: func ptr %s is not set\n",
 847					 map->name, mname);
 848				continue;
 849			}
 850
 851			prog->attach_btf_id = kern_type_id;
 852			prog->expected_attach_type = kern_member_idx;
 853
 854			st_ops->kern_func_off[i] = kern_data_off + kern_moff;
 855
 856			pr_debug("struct_ops init_kern %s: func ptr %s is set to prog %s from data(+%u) to kern_data(+%u)\n",
 857				 map->name, mname, prog->name, moff,
 858				 kern_moff);
 859
 860			continue;
 861		}
 862
 863		msize = btf__resolve_size(btf, mtype_id);
 864		kern_msize = btf__resolve_size(kern_btf, kern_mtype_id);
 865		if (msize < 0 || kern_msize < 0 || msize != kern_msize) {
 866			pr_warn("struct_ops init_kern %s: Error in size of member %s: %zd != %zd(kernel)\n",
 867				map->name, mname, (ssize_t)msize,
 868				(ssize_t)kern_msize);
 869			return -ENOTSUP;
 870		}
 871
 872		pr_debug("struct_ops init_kern %s: copy %s %u bytes from data(+%u) to kern_data(+%u)\n",
 873			 map->name, mname, (unsigned int)msize,
 874			 moff, kern_moff);
 875		memcpy(kern_mdata, mdata, msize);
 876	}
 877
 878	return 0;
 879}
 880
 881static int bpf_object__init_kern_struct_ops_maps(struct bpf_object *obj)
 882{
 883	struct bpf_map *map;
 884	size_t i;
 885	int err;
 886
 887	for (i = 0; i < obj->nr_maps; i++) {
 888		map = &obj->maps[i];
 889
 890		if (!bpf_map__is_struct_ops(map))
 891			continue;
 892
 893		err = bpf_map__init_kern_struct_ops(map, obj->btf,
 894						    obj->btf_vmlinux);
 895		if (err)
 896			return err;
 897	}
 898
 899	return 0;
 900}
 901
 902static int bpf_object__init_struct_ops_maps(struct bpf_object *obj)
 903{
 904	const struct btf_type *type, *datasec;
 905	const struct btf_var_secinfo *vsi;
 906	struct bpf_struct_ops *st_ops;
 907	const char *tname, *var_name;
 908	__s32 type_id, datasec_id;
 909	const struct btf *btf;
 910	struct bpf_map *map;
 911	__u32 i;
 912
 913	if (obj->efile.st_ops_shndx == -1)
 914		return 0;
 915
 916	btf = obj->btf;
 917	datasec_id = btf__find_by_name_kind(btf, STRUCT_OPS_SEC,
 918					    BTF_KIND_DATASEC);
 919	if (datasec_id < 0) {
 920		pr_warn("struct_ops init: DATASEC %s not found\n",
 921			STRUCT_OPS_SEC);
 922		return -EINVAL;
 923	}
 924
 925	datasec = btf__type_by_id(btf, datasec_id);
 926	vsi = btf_var_secinfos(datasec);
 927	for (i = 0; i < btf_vlen(datasec); i++, vsi++) {
 928		type = btf__type_by_id(obj->btf, vsi->type);
 929		var_name = btf__name_by_offset(obj->btf, type->name_off);
 930
 931		type_id = btf__resolve_type(obj->btf, vsi->type);
 932		if (type_id < 0) {
 933			pr_warn("struct_ops init: Cannot resolve var type_id %u in DATASEC %s\n",
 934				vsi->type, STRUCT_OPS_SEC);
 935			return -EINVAL;
 936		}
 937
 938		type = btf__type_by_id(obj->btf, type_id);
 939		tname = btf__name_by_offset(obj->btf, type->name_off);
 940		if (!tname[0]) {
 941			pr_warn("struct_ops init: anonymous type is not supported\n");
 942			return -ENOTSUP;
 943		}
 944		if (!btf_is_struct(type)) {
 945			pr_warn("struct_ops init: %s is not a struct\n", tname);
 946			return -EINVAL;
 947		}
 948
 949		map = bpf_object__add_map(obj);
 950		if (IS_ERR(map))
 951			return PTR_ERR(map);
 952
 953		map->sec_idx = obj->efile.st_ops_shndx;
 954		map->sec_offset = vsi->offset;
 955		map->name = strdup(var_name);
 956		if (!map->name)
 957			return -ENOMEM;
 958
 959		map->def.type = BPF_MAP_TYPE_STRUCT_OPS;
 960		map->def.key_size = sizeof(int);
 961		map->def.value_size = type->size;
 962		map->def.max_entries = 1;
 963
 964		map->st_ops = calloc(1, sizeof(*map->st_ops));
 965		if (!map->st_ops)
 966			return -ENOMEM;
 967		st_ops = map->st_ops;
 968		st_ops->data = malloc(type->size);
 969		st_ops->progs = calloc(btf_vlen(type), sizeof(*st_ops->progs));
 970		st_ops->kern_func_off = malloc(btf_vlen(type) *
 971					       sizeof(*st_ops->kern_func_off));
 972		if (!st_ops->data || !st_ops->progs || !st_ops->kern_func_off)
 973			return -ENOMEM;
 974
 975		if (vsi->offset + type->size > obj->efile.st_ops_data->d_size) {
 976			pr_warn("struct_ops init: var %s is beyond the end of DATASEC %s\n",
 977				var_name, STRUCT_OPS_SEC);
 978			return -EINVAL;
 979		}
 980
 981		memcpy(st_ops->data,
 982		       obj->efile.st_ops_data->d_buf + vsi->offset,
 983		       type->size);
 984		st_ops->tname = tname;
 985		st_ops->type = type;
 986		st_ops->type_id = type_id;
 987
 988		pr_debug("struct_ops init: struct %s(type_id=%u) %s found at offset %u\n",
 989			 tname, type_id, var_name, vsi->offset);
 990	}
 991
 992	return 0;
 993}
 994
 995static struct bpf_object *bpf_object__new(const char *path,
 996					  const void *obj_buf,
 997					  size_t obj_buf_sz,
 998					  const char *obj_name)
 999{
1000	struct bpf_object *obj;
1001	char *end;
1002
1003	obj = calloc(1, sizeof(struct bpf_object) + strlen(path) + 1);
1004	if (!obj) {
1005		pr_warn("alloc memory failed for %s\n", path);
1006		return ERR_PTR(-ENOMEM);
1007	}
1008
1009	strcpy(obj->path, path);
1010	if (obj_name) {
1011		strncpy(obj->name, obj_name, sizeof(obj->name) - 1);
1012		obj->name[sizeof(obj->name) - 1] = 0;
1013	} else {
1014		/* Using basename() GNU version which doesn't modify arg. */
1015		strncpy(obj->name, basename((void *)path),
1016			sizeof(obj->name) - 1);
1017		end = strchr(obj->name, '.');
1018		if (end)
1019			*end = 0;
1020	}
1021
1022	obj->efile.fd = -1;
 
1023	/*
1024	 * Caller of this function should also call
1025	 * bpf_object__elf_finish() after data collection to return
1026	 * obj_buf to user. If not, we should duplicate the buffer to
1027	 * avoid user freeing them before elf finish.
1028	 */
1029	obj->efile.obj_buf = obj_buf;
1030	obj->efile.obj_buf_sz = obj_buf_sz;
1031	obj->efile.maps_shndx = -1;
1032	obj->efile.btf_maps_shndx = -1;
1033	obj->efile.data_shndx = -1;
1034	obj->efile.rodata_shndx = -1;
1035	obj->efile.bss_shndx = -1;
1036	obj->efile.st_ops_shndx = -1;
1037	obj->kconfig_map_idx = -1;
1038
1039	obj->kern_version = get_kernel_version();
1040	obj->loaded = false;
1041
1042	INIT_LIST_HEAD(&obj->list);
1043	list_add(&obj->list, &bpf_objects_list);
1044	return obj;
1045}
1046
1047static void bpf_object__elf_finish(struct bpf_object *obj)
1048{
1049	if (!obj_elf_valid(obj))
1050		return;
1051
1052	if (obj->efile.elf) {
1053		elf_end(obj->efile.elf);
1054		obj->efile.elf = NULL;
1055	}
1056	obj->efile.symbols = NULL;
1057	obj->efile.data = NULL;
1058	obj->efile.rodata = NULL;
1059	obj->efile.bss = NULL;
1060	obj->efile.st_ops_data = NULL;
1061
1062	zfree(&obj->efile.reloc_sects);
1063	obj->efile.nr_reloc_sects = 0;
1064	zclose(obj->efile.fd);
1065	obj->efile.obj_buf = NULL;
1066	obj->efile.obj_buf_sz = 0;
1067}
1068
1069static int bpf_object__elf_init(struct bpf_object *obj)
1070{
1071	int err = 0;
1072	GElf_Ehdr *ep;
1073
1074	if (obj_elf_valid(obj)) {
1075		pr_warn("elf init: internal error\n");
1076		return -LIBBPF_ERRNO__LIBELF;
1077	}
1078
1079	if (obj->efile.obj_buf_sz > 0) {
1080		/*
1081		 * obj_buf should have been validated by
1082		 * bpf_object__open_buffer().
1083		 */
1084		obj->efile.elf = elf_memory((char *)obj->efile.obj_buf,
1085					    obj->efile.obj_buf_sz);
1086	} else {
1087		obj->efile.fd = open(obj->path, O_RDONLY);
1088		if (obj->efile.fd < 0) {
1089			char errmsg[STRERR_BUFSIZE], *cp;
1090
1091			err = -errno;
1092			cp = libbpf_strerror_r(err, errmsg, sizeof(errmsg));
1093			pr_warn("failed to open %s: %s\n", obj->path, cp);
1094			return err;
1095		}
1096
1097		obj->efile.elf = elf_begin(obj->efile.fd,
1098					   LIBBPF_ELF_C_READ_MMAP, NULL);
 
1099	}
1100
1101	if (!obj->efile.elf) {
1102		pr_warn("failed to open %s as ELF file\n", obj->path);
 
1103		err = -LIBBPF_ERRNO__LIBELF;
1104		goto errout;
1105	}
1106
1107	if (!gelf_getehdr(obj->efile.elf, &obj->efile.ehdr)) {
1108		pr_warn("failed to get EHDR from %s\n", obj->path);
 
1109		err = -LIBBPF_ERRNO__FORMAT;
1110		goto errout;
1111	}
1112	ep = &obj->efile.ehdr;
1113
1114	/* Old LLVM set e_machine to EM_NONE */
1115	if (ep->e_type != ET_REL ||
1116	    (ep->e_machine && ep->e_machine != EM_BPF)) {
1117		pr_warn("%s is not an eBPF object file\n", obj->path);
1118		err = -LIBBPF_ERRNO__FORMAT;
1119		goto errout;
1120	}
1121
1122	return 0;
1123errout:
1124	bpf_object__elf_finish(obj);
1125	return err;
1126}
1127
1128static int bpf_object__check_endianness(struct bpf_object *obj)
 
1129{
1130#if __BYTE_ORDER == __LITTLE_ENDIAN
1131	if (obj->efile.ehdr.e_ident[EI_DATA] == ELFDATA2LSB)
1132		return 0;
1133#elif __BYTE_ORDER == __BIG_ENDIAN
1134	if (obj->efile.ehdr.e_ident[EI_DATA] == ELFDATA2MSB)
1135		return 0;
1136#else
1137# error "Unrecognized __BYTE_ORDER__"
1138#endif
1139	pr_warn("endianness mismatch.\n");
 
 
 
 
 
 
 
 
 
 
 
 
1140	return -LIBBPF_ERRNO__ENDIAN;
1141}
1142
1143static int
1144bpf_object__init_license(struct bpf_object *obj, void *data, size_t size)
 
1145{
1146	memcpy(obj->license, data, min(size, sizeof(obj->license) - 1));
 
1147	pr_debug("license of %s is %s\n", obj->path, obj->license);
1148	return 0;
1149}
1150
1151static int
1152bpf_object__init_kversion(struct bpf_object *obj, void *data, size_t size)
 
1153{
1154	__u32 kver;
1155
1156	if (size != sizeof(kver)) {
1157		pr_warn("invalid kver section in %s\n", obj->path);
1158		return -LIBBPF_ERRNO__FORMAT;
1159	}
1160	memcpy(&kver, data, sizeof(kver));
1161	obj->kern_version = kver;
1162	pr_debug("kernel version of %s is %x\n", obj->path, obj->kern_version);
 
1163	return 0;
1164}
1165
1166static bool bpf_map_type__is_map_in_map(enum bpf_map_type type)
1167{
1168	if (type == BPF_MAP_TYPE_ARRAY_OF_MAPS ||
1169	    type == BPF_MAP_TYPE_HASH_OF_MAPS)
1170		return true;
1171	return false;
1172}
1173
1174static int bpf_object_search_section_size(const struct bpf_object *obj,
1175					  const char *name, size_t *d_size)
1176{
1177	const GElf_Ehdr *ep = &obj->efile.ehdr;
1178	Elf *elf = obj->efile.elf;
1179	Elf_Scn *scn = NULL;
1180	int idx = 0;
1181
1182	while ((scn = elf_nextscn(elf, scn)) != NULL) {
1183		const char *sec_name;
1184		Elf_Data *data;
1185		GElf_Shdr sh;
1186
1187		idx++;
1188		if (gelf_getshdr(scn, &sh) != &sh) {
1189			pr_warn("failed to get section(%d) header from %s\n",
1190				idx, obj->path);
1191			return -EIO;
1192		}
1193
1194		sec_name = elf_strptr(elf, ep->e_shstrndx, sh.sh_name);
1195		if (!sec_name) {
1196			pr_warn("failed to get section(%d) name from %s\n",
1197				idx, obj->path);
1198			return -EIO;
1199		}
1200
1201		if (strcmp(name, sec_name))
1202			continue;
1203
1204		data = elf_getdata(scn, 0);
1205		if (!data) {
1206			pr_warn("failed to get section(%d) data from %s(%s)\n",
1207				idx, name, obj->path);
1208			return -EIO;
1209		}
1210
1211		*d_size = data->d_size;
1212		return 0;
1213	}
1214
1215	return -ENOENT;
1216}
1217
1218int bpf_object__section_size(const struct bpf_object *obj, const char *name,
1219			     __u32 *size)
1220{
1221	int ret = -ENOENT;
1222	size_t d_size;
1223
1224	*size = 0;
1225	if (!name) {
1226		return -EINVAL;
1227	} else if (!strcmp(name, DATA_SEC)) {
1228		if (obj->efile.data)
1229			*size = obj->efile.data->d_size;
1230	} else if (!strcmp(name, BSS_SEC)) {
1231		if (obj->efile.bss)
1232			*size = obj->efile.bss->d_size;
1233	} else if (!strcmp(name, RODATA_SEC)) {
1234		if (obj->efile.rodata)
1235			*size = obj->efile.rodata->d_size;
1236	} else if (!strcmp(name, STRUCT_OPS_SEC)) {
1237		if (obj->efile.st_ops_data)
1238			*size = obj->efile.st_ops_data->d_size;
1239	} else {
1240		ret = bpf_object_search_section_size(obj, name, &d_size);
1241		if (!ret)
1242			*size = d_size;
1243	}
1244
1245	return *size ? 0 : ret;
1246}
1247
1248int bpf_object__variable_offset(const struct bpf_object *obj, const char *name,
1249				__u32 *off)
1250{
1251	Elf_Data *symbols = obj->efile.symbols;
1252	const char *sname;
1253	size_t si;
1254
1255	if (!name || !off)
1256		return -EINVAL;
1257
1258	for (si = 0; si < symbols->d_size / sizeof(GElf_Sym); si++) {
1259		GElf_Sym sym;
1260
1261		if (!gelf_getsym(symbols, si, &sym))
1262			continue;
1263		if (GELF_ST_BIND(sym.st_info) != STB_GLOBAL ||
1264		    GELF_ST_TYPE(sym.st_info) != STT_OBJECT)
1265			continue;
1266
1267		sname = elf_strptr(obj->efile.elf, obj->efile.strtabidx,
1268				   sym.st_name);
1269		if (!sname) {
1270			pr_warn("failed to get sym name string for var %s\n",
1271				name);
1272			return -EIO;
1273		}
1274		if (strcmp(name, sname) == 0) {
1275			*off = sym.st_value;
1276			return 0;
1277		}
1278	}
1279
1280	return -ENOENT;
1281}
1282
1283static struct bpf_map *bpf_object__add_map(struct bpf_object *obj)
1284{
1285	struct bpf_map *new_maps;
1286	size_t new_cap;
1287	int i;
1288
1289	if (obj->nr_maps < obj->maps_cap)
1290		return &obj->maps[obj->nr_maps++];
1291
1292	new_cap = max((size_t)4, obj->maps_cap * 3 / 2);
1293	new_maps = realloc(obj->maps, new_cap * sizeof(*obj->maps));
1294	if (!new_maps) {
1295		pr_warn("alloc maps for object failed\n");
1296		return ERR_PTR(-ENOMEM);
1297	}
1298
1299	obj->maps_cap = new_cap;
1300	obj->maps = new_maps;
1301
1302	/* zero out new maps */
1303	memset(obj->maps + obj->nr_maps, 0,
1304	       (obj->maps_cap - obj->nr_maps) * sizeof(*obj->maps));
1305	/*
1306	 * fill all fd with -1 so won't close incorrect fd (fd=0 is stdin)
1307	 * when failure (zclose won't close negative fd)).
1308	 */
1309	for (i = obj->nr_maps; i < obj->maps_cap; i++) {
1310		obj->maps[i].fd = -1;
1311		obj->maps[i].inner_map_fd = -1;
1312	}
1313
1314	return &obj->maps[obj->nr_maps++];
1315}
1316
1317static size_t bpf_map_mmap_sz(const struct bpf_map *map)
1318{
1319	long page_sz = sysconf(_SC_PAGE_SIZE);
1320	size_t map_sz;
1321
1322	map_sz = (size_t)roundup(map->def.value_size, 8) * map->def.max_entries;
1323	map_sz = roundup(map_sz, page_sz);
1324	return map_sz;
1325}
1326
1327static char *internal_map_name(struct bpf_object *obj,
1328			       enum libbpf_map_type type)
1329{
1330	char map_name[BPF_OBJ_NAME_LEN], *p;
1331	const char *sfx = libbpf_type_to_btf_name[type];
1332	int sfx_len = max((size_t)7, strlen(sfx));
1333	int pfx_len = min((size_t)BPF_OBJ_NAME_LEN - sfx_len - 1,
1334			  strlen(obj->name));
1335
1336	snprintf(map_name, sizeof(map_name), "%.*s%.*s", pfx_len, obj->name,
1337		 sfx_len, libbpf_type_to_btf_name[type]);
1338
1339	/* sanitise map name to characters allowed by kernel */
1340	for (p = map_name; *p && p < map_name + sizeof(map_name); p++)
1341		if (!isalnum(*p) && *p != '_' && *p != '.')
1342			*p = '_';
1343
1344	return strdup(map_name);
1345}
1346
1347static int
1348bpf_object__init_internal_map(struct bpf_object *obj, enum libbpf_map_type type,
1349			      int sec_idx, void *data, size_t data_sz)
1350{
1351	struct bpf_map_def *def;
1352	struct bpf_map *map;
1353	int err;
1354
1355	map = bpf_object__add_map(obj);
1356	if (IS_ERR(map))
1357		return PTR_ERR(map);
1358
1359	map->libbpf_type = type;
1360	map->sec_idx = sec_idx;
1361	map->sec_offset = 0;
1362	map->name = internal_map_name(obj, type);
1363	if (!map->name) {
1364		pr_warn("failed to alloc map name\n");
1365		return -ENOMEM;
1366	}
1367
1368	def = &map->def;
1369	def->type = BPF_MAP_TYPE_ARRAY;
1370	def->key_size = sizeof(int);
1371	def->value_size = data_sz;
1372	def->max_entries = 1;
1373	def->map_flags = type == LIBBPF_MAP_RODATA || type == LIBBPF_MAP_KCONFIG
1374			 ? BPF_F_RDONLY_PROG : 0;
1375	def->map_flags |= BPF_F_MMAPABLE;
1376
1377	pr_debug("map '%s' (global data): at sec_idx %d, offset %zu, flags %x.\n",
1378		 map->name, map->sec_idx, map->sec_offset, def->map_flags);
1379
1380	map->mmaped = mmap(NULL, bpf_map_mmap_sz(map), PROT_READ | PROT_WRITE,
1381			   MAP_SHARED | MAP_ANONYMOUS, -1, 0);
1382	if (map->mmaped == MAP_FAILED) {
1383		err = -errno;
1384		map->mmaped = NULL;
1385		pr_warn("failed to alloc map '%s' content buffer: %d\n",
1386			map->name, err);
1387		zfree(&map->name);
1388		return err;
1389	}
1390
1391	if (data)
1392		memcpy(map->mmaped, data, data_sz);
1393
1394	pr_debug("map %td is \"%s\"\n", map - obj->maps, map->name);
1395	return 0;
1396}
1397
1398static int bpf_object__init_global_data_maps(struct bpf_object *obj)
1399{
1400	int err;
1401
1402	/*
1403	 * Populate obj->maps with libbpf internal maps.
1404	 */
1405	if (obj->efile.data_shndx >= 0) {
1406		err = bpf_object__init_internal_map(obj, LIBBPF_MAP_DATA,
1407						    obj->efile.data_shndx,
1408						    obj->efile.data->d_buf,
1409						    obj->efile.data->d_size);
1410		if (err)
1411			return err;
1412	}
1413	if (obj->efile.rodata_shndx >= 0) {
1414		err = bpf_object__init_internal_map(obj, LIBBPF_MAP_RODATA,
1415						    obj->efile.rodata_shndx,
1416						    obj->efile.rodata->d_buf,
1417						    obj->efile.rodata->d_size);
1418		if (err)
1419			return err;
1420	}
1421	if (obj->efile.bss_shndx >= 0) {
1422		err = bpf_object__init_internal_map(obj, LIBBPF_MAP_BSS,
1423						    obj->efile.bss_shndx,
1424						    NULL,
1425						    obj->efile.bss->d_size);
1426		if (err)
1427			return err;
1428	}
1429	return 0;
1430}
1431
1432
1433static struct extern_desc *find_extern_by_name(const struct bpf_object *obj,
1434					       const void *name)
1435{
1436	int i;
1437
1438	for (i = 0; i < obj->nr_extern; i++) {
1439		if (strcmp(obj->externs[i].name, name) == 0)
1440			return &obj->externs[i];
1441	}
1442	return NULL;
1443}
1444
1445static int set_kcfg_value_tri(struct extern_desc *ext, void *ext_val,
1446			      char value)
1447{
1448	switch (ext->kcfg.type) {
1449	case KCFG_BOOL:
1450		if (value == 'm') {
1451			pr_warn("extern (kcfg) %s=%c should be tristate or char\n",
1452				ext->name, value);
1453			return -EINVAL;
1454		}
1455		*(bool *)ext_val = value == 'y' ? true : false;
1456		break;
1457	case KCFG_TRISTATE:
1458		if (value == 'y')
1459			*(enum libbpf_tristate *)ext_val = TRI_YES;
1460		else if (value == 'm')
1461			*(enum libbpf_tristate *)ext_val = TRI_MODULE;
1462		else /* value == 'n' */
1463			*(enum libbpf_tristate *)ext_val = TRI_NO;
1464		break;
1465	case KCFG_CHAR:
1466		*(char *)ext_val = value;
1467		break;
1468	case KCFG_UNKNOWN:
1469	case KCFG_INT:
1470	case KCFG_CHAR_ARR:
1471	default:
1472		pr_warn("extern (kcfg) %s=%c should be bool, tristate, or char\n",
1473			ext->name, value);
1474		return -EINVAL;
1475	}
1476	ext->is_set = true;
1477	return 0;
1478}
1479
1480static int set_kcfg_value_str(struct extern_desc *ext, char *ext_val,
1481			      const char *value)
1482{
1483	size_t len;
1484
1485	if (ext->kcfg.type != KCFG_CHAR_ARR) {
1486		pr_warn("extern (kcfg) %s=%s should be char array\n", ext->name, value);
1487		return -EINVAL;
1488	}
1489
1490	len = strlen(value);
1491	if (value[len - 1] != '"') {
1492		pr_warn("extern (kcfg) '%s': invalid string config '%s'\n",
1493			ext->name, value);
1494		return -EINVAL;
1495	}
1496
1497	/* strip quotes */
1498	len -= 2;
1499	if (len >= ext->kcfg.sz) {
1500		pr_warn("extern (kcfg) '%s': long string config %s of (%zu bytes) truncated to %d bytes\n",
1501			ext->name, value, len, ext->kcfg.sz - 1);
1502		len = ext->kcfg.sz - 1;
1503	}
1504	memcpy(ext_val, value + 1, len);
1505	ext_val[len] = '\0';
1506	ext->is_set = true;
1507	return 0;
1508}
1509
1510static int parse_u64(const char *value, __u64 *res)
1511{
1512	char *value_end;
1513	int err;
1514
1515	errno = 0;
1516	*res = strtoull(value, &value_end, 0);
1517	if (errno) {
1518		err = -errno;
1519		pr_warn("failed to parse '%s' as integer: %d\n", value, err);
1520		return err;
1521	}
1522	if (*value_end) {
1523		pr_warn("failed to parse '%s' as integer completely\n", value);
1524		return -EINVAL;
1525	}
1526	return 0;
1527}
1528
1529static bool is_kcfg_value_in_range(const struct extern_desc *ext, __u64 v)
1530{
1531	int bit_sz = ext->kcfg.sz * 8;
1532
1533	if (ext->kcfg.sz == 8)
1534		return true;
1535
1536	/* Validate that value stored in u64 fits in integer of `ext->sz`
1537	 * bytes size without any loss of information. If the target integer
1538	 * is signed, we rely on the following limits of integer type of
1539	 * Y bits and subsequent transformation:
1540	 *
1541	 *     -2^(Y-1) <= X           <= 2^(Y-1) - 1
1542	 *            0 <= X + 2^(Y-1) <= 2^Y - 1
1543	 *            0 <= X + 2^(Y-1) <  2^Y
1544	 *
1545	 *  For unsigned target integer, check that all the (64 - Y) bits are
1546	 *  zero.
1547	 */
1548	if (ext->kcfg.is_signed)
1549		return v + (1ULL << (bit_sz - 1)) < (1ULL << bit_sz);
1550	else
1551		return (v >> bit_sz) == 0;
1552}
1553
1554static int set_kcfg_value_num(struct extern_desc *ext, void *ext_val,
1555			      __u64 value)
1556{
1557	if (ext->kcfg.type != KCFG_INT && ext->kcfg.type != KCFG_CHAR) {
1558		pr_warn("extern (kcfg) %s=%llu should be integer\n",
1559			ext->name, (unsigned long long)value);
1560		return -EINVAL;
1561	}
1562	if (!is_kcfg_value_in_range(ext, value)) {
1563		pr_warn("extern (kcfg) %s=%llu value doesn't fit in %d bytes\n",
1564			ext->name, (unsigned long long)value, ext->kcfg.sz);
1565		return -ERANGE;
1566	}
1567	switch (ext->kcfg.sz) {
1568		case 1: *(__u8 *)ext_val = value; break;
1569		case 2: *(__u16 *)ext_val = value; break;
1570		case 4: *(__u32 *)ext_val = value; break;
1571		case 8: *(__u64 *)ext_val = value; break;
1572		default:
1573			return -EINVAL;
1574	}
1575	ext->is_set = true;
1576	return 0;
1577}
1578
1579static int bpf_object__process_kconfig_line(struct bpf_object *obj,
1580					    char *buf, void *data)
1581{
1582	struct extern_desc *ext;
1583	char *sep, *value;
1584	int len, err = 0;
1585	void *ext_val;
1586	__u64 num;
1587
1588	if (strncmp(buf, "CONFIG_", 7))
1589		return 0;
1590
1591	sep = strchr(buf, '=');
1592	if (!sep) {
1593		pr_warn("failed to parse '%s': no separator\n", buf);
1594		return -EINVAL;
1595	}
1596
1597	/* Trim ending '\n' */
1598	len = strlen(buf);
1599	if (buf[len - 1] == '\n')
1600		buf[len - 1] = '\0';
1601	/* Split on '=' and ensure that a value is present. */
1602	*sep = '\0';
1603	if (!sep[1]) {
1604		*sep = '=';
1605		pr_warn("failed to parse '%s': no value\n", buf);
1606		return -EINVAL;
1607	}
1608
1609	ext = find_extern_by_name(obj, buf);
1610	if (!ext || ext->is_set)
1611		return 0;
1612
1613	ext_val = data + ext->kcfg.data_off;
1614	value = sep + 1;
 
1615
1616	switch (*value) {
1617	case 'y': case 'n': case 'm':
1618		err = set_kcfg_value_tri(ext, ext_val, *value);
1619		break;
1620	case '"':
1621		err = set_kcfg_value_str(ext, ext_val, value);
1622		break;
1623	default:
1624		/* assume integer */
1625		err = parse_u64(value, &num);
1626		if (err) {
1627			pr_warn("extern (kcfg) %s=%s should be integer\n",
1628				ext->name, value);
1629			return err;
1630		}
1631		err = set_kcfg_value_num(ext, ext_val, num);
1632		break;
1633	}
1634	if (err)
1635		return err;
1636	pr_debug("extern (kcfg) %s=%s\n", ext->name, value);
1637	return 0;
1638}
1639
1640static int bpf_object__read_kconfig_file(struct bpf_object *obj, void *data)
1641{
1642	char buf[PATH_MAX];
1643	struct utsname uts;
1644	int len, err = 0;
1645	gzFile file;
1646
1647	uname(&uts);
1648	len = snprintf(buf, PATH_MAX, "/boot/config-%s", uts.release);
1649	if (len < 0)
1650		return -EINVAL;
1651	else if (len >= PATH_MAX)
1652		return -ENAMETOOLONG;
1653
1654	/* gzopen also accepts uncompressed files. */
1655	file = gzopen(buf, "r");
1656	if (!file)
1657		file = gzopen("/proc/config.gz", "r");
1658
1659	if (!file) {
1660		pr_warn("failed to open system Kconfig\n");
1661		return -ENOENT;
1662	}
1663
1664	while (gzgets(file, buf, sizeof(buf))) {
1665		err = bpf_object__process_kconfig_line(obj, buf, data);
1666		if (err) {
1667			pr_warn("error parsing system Kconfig line '%s': %d\n",
1668				buf, err);
1669			goto out;
1670		}
1671	}
1672
1673out:
1674	gzclose(file);
1675	return err;
1676}
1677
1678static int bpf_object__read_kconfig_mem(struct bpf_object *obj,
1679					const char *config, void *data)
1680{
1681	char buf[PATH_MAX];
1682	int err = 0;
1683	FILE *file;
1684
1685	file = fmemopen((void *)config, strlen(config), "r");
1686	if (!file) {
1687		err = -errno;
1688		pr_warn("failed to open in-memory Kconfig: %d\n", err);
1689		return err;
1690	}
1691
1692	while (fgets(buf, sizeof(buf), file)) {
1693		err = bpf_object__process_kconfig_line(obj, buf, data);
1694		if (err) {
1695			pr_warn("error parsing in-memory Kconfig line '%s': %d\n",
1696				buf, err);
1697			break;
1698		}
1699	}
1700
1701	fclose(file);
1702	return err;
1703}
1704
1705static int bpf_object__init_kconfig_map(struct bpf_object *obj)
1706{
1707	struct extern_desc *last_ext = NULL, *ext;
1708	size_t map_sz;
1709	int i, err;
1710
1711	for (i = 0; i < obj->nr_extern; i++) {
1712		ext = &obj->externs[i];
1713		if (ext->type == EXT_KCFG)
1714			last_ext = ext;
1715	}
1716
1717	if (!last_ext)
1718		return 0;
1719
1720	map_sz = last_ext->kcfg.data_off + last_ext->kcfg.sz;
1721	err = bpf_object__init_internal_map(obj, LIBBPF_MAP_KCONFIG,
1722					    obj->efile.symbols_shndx,
1723					    NULL, map_sz);
1724	if (err)
1725		return err;
1726
1727	obj->kconfig_map_idx = obj->nr_maps - 1;
1728
1729	return 0;
1730}
1731
1732static int bpf_object__init_user_maps(struct bpf_object *obj, bool strict)
1733{
1734	Elf_Data *symbols = obj->efile.symbols;
1735	int i, map_def_sz = 0, nr_maps = 0, nr_syms;
1736	Elf_Data *data = NULL;
1737	Elf_Scn *scn;
 
 
1738
1739	if (obj->efile.maps_shndx < 0)
1740		return 0;
1741
1742	if (!symbols)
1743		return -EINVAL;
1744
1745	scn = elf_getscn(obj->efile.elf, obj->efile.maps_shndx);
1746	if (scn)
1747		data = elf_getdata(scn, NULL);
1748	if (!scn || !data) {
1749		pr_warn("failed to get Elf_Data from map section %d\n",
1750			obj->efile.maps_shndx);
1751		return -EINVAL;
1752	}
1753
1754	/*
1755	 * Count number of maps. Each map has a name.
1756	 * Array of maps is not supported: only the first element is
1757	 * considered.
1758	 *
1759	 * TODO: Detect array of map and report error.
1760	 */
1761	nr_syms = symbols->d_size / sizeof(GElf_Sym);
1762	for (i = 0; i < nr_syms; i++) {
1763		GElf_Sym sym;
1764
1765		if (!gelf_getsym(symbols, i, &sym))
1766			continue;
1767		if (sym.st_shndx != obj->efile.maps_shndx)
1768			continue;
1769		nr_maps++;
1770	}
1771	/* Assume equally sized map definitions */
1772	pr_debug("maps in %s: %d maps in %zd bytes\n",
1773		 obj->path, nr_maps, data->d_size);
1774
1775	if (!data->d_size || nr_maps == 0 || (data->d_size % nr_maps) != 0) {
1776		pr_warn("unable to determine map definition size section %s, %d maps in %zd bytes\n",
1777			obj->path, nr_maps, data->d_size);
1778		return -EINVAL;
 
 
 
 
1779	}
1780	map_def_sz = data->d_size / nr_maps;
1781
1782	/* Fill obj->maps using data in "maps" section.  */
1783	for (i = 0; i < nr_syms; i++) {
 
 
 
 
 
 
 
 
 
 
1784		GElf_Sym sym;
1785		const char *map_name;
1786		struct bpf_map_def *def;
1787		struct bpf_map *map;
1788
1789		if (!gelf_getsym(symbols, i, &sym))
1790			continue;
1791		if (sym.st_shndx != obj->efile.maps_shndx)
1792			continue;
1793
1794		map = bpf_object__add_map(obj);
1795		if (IS_ERR(map))
1796			return PTR_ERR(map);
1797
1798		map_name = elf_strptr(obj->efile.elf, obj->efile.strtabidx,
1799				      sym.st_name);
1800		if (!map_name) {
1801			pr_warn("failed to get map #%d name sym string for obj %s\n",
1802				i, obj->path);
1803			return -LIBBPF_ERRNO__FORMAT;
1804		}
1805
1806		map->libbpf_type = LIBBPF_MAP_UNSPEC;
1807		map->sec_idx = sym.st_shndx;
1808		map->sec_offset = sym.st_value;
1809		pr_debug("map '%s' (legacy): at sec_idx %d, offset %zu.\n",
1810			 map_name, map->sec_idx, map->sec_offset);
1811		if (sym.st_value + map_def_sz > data->d_size) {
1812			pr_warn("corrupted maps section in %s: last map \"%s\" too small\n",
1813				obj->path, map_name);
1814			return -EINVAL;
1815		}
1816
1817		map->name = strdup(map_name);
1818		if (!map->name) {
1819			pr_warn("failed to alloc map name\n");
1820			return -ENOMEM;
1821		}
1822		pr_debug("map %d is \"%s\"\n", i, map->name);
 
1823		def = (struct bpf_map_def *)(data->d_buf + sym.st_value);
1824		/*
1825		 * If the definition of the map in the object file fits in
1826		 * bpf_map_def, copy it.  Any extra fields in our version
1827		 * of bpf_map_def will default to zero as a result of the
1828		 * calloc above.
1829		 */
1830		if (map_def_sz <= sizeof(struct bpf_map_def)) {
1831			memcpy(&map->def, def, map_def_sz);
1832		} else {
1833			/*
1834			 * Here the map structure being read is bigger than what
1835			 * we expect, truncate if the excess bits are all zero.
1836			 * If they are not zero, reject this map as
1837			 * incompatible.
1838			 */
1839			char *b;
1840
1841			for (b = ((char *)def) + sizeof(struct bpf_map_def);
1842			     b < ((char *)def) + map_def_sz; b++) {
1843				if (*b != 0) {
1844					pr_warn("maps section in %s: \"%s\" has unrecognized, non-zero options\n",
1845						obj->path, map_name);
1846					if (strict)
1847						return -EINVAL;
1848				}
1849			}
1850			memcpy(&map->def, def, sizeof(struct bpf_map_def));
1851		}
1852	}
1853	return 0;
1854}
1855
1856static const struct btf_type *
1857skip_mods_and_typedefs(const struct btf *btf, __u32 id, __u32 *res_id)
1858{
1859	const struct btf_type *t = btf__type_by_id(btf, id);
1860
1861	if (res_id)
1862		*res_id = id;
1863
1864	while (btf_is_mod(t) || btf_is_typedef(t)) {
1865		if (res_id)
1866			*res_id = t->type;
1867		t = btf__type_by_id(btf, t->type);
1868	}
1869
1870	return t;
1871}
1872
1873static const struct btf_type *
1874resolve_func_ptr(const struct btf *btf, __u32 id, __u32 *res_id)
1875{
1876	const struct btf_type *t;
1877
1878	t = skip_mods_and_typedefs(btf, id, NULL);
1879	if (!btf_is_ptr(t))
1880		return NULL;
1881
1882	t = skip_mods_and_typedefs(btf, t->type, res_id);
1883
1884	return btf_is_func_proto(t) ? t : NULL;
1885}
1886
1887/*
1888 * Fetch integer attribute of BTF map definition. Such attributes are
1889 * represented using a pointer to an array, in which dimensionality of array
1890 * encodes specified integer value. E.g., int (*type)[BPF_MAP_TYPE_ARRAY];
1891 * encodes `type => BPF_MAP_TYPE_ARRAY` key/value pair completely using BTF
1892 * type definition, while using only sizeof(void *) space in ELF data section.
1893 */
1894static bool get_map_field_int(const char *map_name, const struct btf *btf,
1895			      const struct btf_member *m, __u32 *res)
1896{
1897	const struct btf_type *t = skip_mods_and_typedefs(btf, m->type, NULL);
1898	const char *name = btf__name_by_offset(btf, m->name_off);
1899	const struct btf_array *arr_info;
1900	const struct btf_type *arr_t;
1901
1902	if (!btf_is_ptr(t)) {
1903		pr_warn("map '%s': attr '%s': expected PTR, got %u.\n",
1904			map_name, name, btf_kind(t));
1905		return false;
1906	}
1907
1908	arr_t = btf__type_by_id(btf, t->type);
1909	if (!arr_t) {
1910		pr_warn("map '%s': attr '%s': type [%u] not found.\n",
1911			map_name, name, t->type);
1912		return false;
1913	}
1914	if (!btf_is_array(arr_t)) {
1915		pr_warn("map '%s': attr '%s': expected ARRAY, got %u.\n",
1916			map_name, name, btf_kind(arr_t));
1917		return false;
1918	}
1919	arr_info = btf_array(arr_t);
1920	*res = arr_info->nelems;
1921	return true;
1922}
1923
1924static int build_map_pin_path(struct bpf_map *map, const char *path)
1925{
1926	char buf[PATH_MAX];
1927	int err, len;
1928
1929	if (!path)
1930		path = "/sys/fs/bpf";
1931
1932	len = snprintf(buf, PATH_MAX, "%s/%s", path, bpf_map__name(map));
1933	if (len < 0)
1934		return -EINVAL;
1935	else if (len >= PATH_MAX)
1936		return -ENAMETOOLONG;
1937
1938	err = bpf_map__set_pin_path(map, buf);
1939	if (err)
1940		return err;
1941
1942	return 0;
1943}
1944
1945
1946static int parse_btf_map_def(struct bpf_object *obj,
1947			     struct bpf_map *map,
1948			     const struct btf_type *def,
1949			     bool strict, bool is_inner,
1950			     const char *pin_root_path)
1951{
1952	const struct btf_type *t;
1953	const struct btf_member *m;
1954	int vlen, i;
1955
1956	vlen = btf_vlen(def);
1957	m = btf_members(def);
1958	for (i = 0; i < vlen; i++, m++) {
1959		const char *name = btf__name_by_offset(obj->btf, m->name_off);
1960
1961		if (!name) {
1962			pr_warn("map '%s': invalid field #%d.\n", map->name, i);
1963			return -EINVAL;
1964		}
1965		if (strcmp(name, "type") == 0) {
1966			if (!get_map_field_int(map->name, obj->btf, m,
1967					       &map->def.type))
1968				return -EINVAL;
1969			pr_debug("map '%s': found type = %u.\n",
1970				 map->name, map->def.type);
1971		} else if (strcmp(name, "max_entries") == 0) {
1972			if (!get_map_field_int(map->name, obj->btf, m,
1973					       &map->def.max_entries))
1974				return -EINVAL;
1975			pr_debug("map '%s': found max_entries = %u.\n",
1976				 map->name, map->def.max_entries);
1977		} else if (strcmp(name, "map_flags") == 0) {
1978			if (!get_map_field_int(map->name, obj->btf, m,
1979					       &map->def.map_flags))
1980				return -EINVAL;
1981			pr_debug("map '%s': found map_flags = %u.\n",
1982				 map->name, map->def.map_flags);
1983		} else if (strcmp(name, "numa_node") == 0) {
1984			if (!get_map_field_int(map->name, obj->btf, m, &map->numa_node))
1985				return -EINVAL;
1986			pr_debug("map '%s': found numa_node = %u.\n", map->name, map->numa_node);
1987		} else if (strcmp(name, "key_size") == 0) {
1988			__u32 sz;
1989
1990			if (!get_map_field_int(map->name, obj->btf, m, &sz))
1991				return -EINVAL;
1992			pr_debug("map '%s': found key_size = %u.\n",
1993				 map->name, sz);
1994			if (map->def.key_size && map->def.key_size != sz) {
1995				pr_warn("map '%s': conflicting key size %u != %u.\n",
1996					map->name, map->def.key_size, sz);
1997				return -EINVAL;
1998			}
1999			map->def.key_size = sz;
2000		} else if (strcmp(name, "key") == 0) {
2001			__s64 sz;
2002
2003			t = btf__type_by_id(obj->btf, m->type);
2004			if (!t) {
2005				pr_warn("map '%s': key type [%d] not found.\n",
2006					map->name, m->type);
2007				return -EINVAL;
2008			}
2009			if (!btf_is_ptr(t)) {
2010				pr_warn("map '%s': key spec is not PTR: %u.\n",
2011					map->name, btf_kind(t));
2012				return -EINVAL;
2013			}
2014			sz = btf__resolve_size(obj->btf, t->type);
2015			if (sz < 0) {
2016				pr_warn("map '%s': can't determine key size for type [%u]: %zd.\n",
2017					map->name, t->type, (ssize_t)sz);
2018				return sz;
2019			}
2020			pr_debug("map '%s': found key [%u], sz = %zd.\n",
2021				 map->name, t->type, (ssize_t)sz);
2022			if (map->def.key_size && map->def.key_size != sz) {
2023				pr_warn("map '%s': conflicting key size %u != %zd.\n",
2024					map->name, map->def.key_size, (ssize_t)sz);
2025				return -EINVAL;
2026			}
2027			map->def.key_size = sz;
2028			map->btf_key_type_id = t->type;
2029		} else if (strcmp(name, "value_size") == 0) {
2030			__u32 sz;
2031
2032			if (!get_map_field_int(map->name, obj->btf, m, &sz))
2033				return -EINVAL;
2034			pr_debug("map '%s': found value_size = %u.\n",
2035				 map->name, sz);
2036			if (map->def.value_size && map->def.value_size != sz) {
2037				pr_warn("map '%s': conflicting value size %u != %u.\n",
2038					map->name, map->def.value_size, sz);
2039				return -EINVAL;
2040			}
2041			map->def.value_size = sz;
2042		} else if (strcmp(name, "value") == 0) {
2043			__s64 sz;
2044
2045			t = btf__type_by_id(obj->btf, m->type);
2046			if (!t) {
2047				pr_warn("map '%s': value type [%d] not found.\n",
2048					map->name, m->type);
2049				return -EINVAL;
2050			}
2051			if (!btf_is_ptr(t)) {
2052				pr_warn("map '%s': value spec is not PTR: %u.\n",
2053					map->name, btf_kind(t));
2054				return -EINVAL;
2055			}
2056			sz = btf__resolve_size(obj->btf, t->type);
2057			if (sz < 0) {
2058				pr_warn("map '%s': can't determine value size for type [%u]: %zd.\n",
2059					map->name, t->type, (ssize_t)sz);
2060				return sz;
2061			}
2062			pr_debug("map '%s': found value [%u], sz = %zd.\n",
2063				 map->name, t->type, (ssize_t)sz);
2064			if (map->def.value_size && map->def.value_size != sz) {
2065				pr_warn("map '%s': conflicting value size %u != %zd.\n",
2066					map->name, map->def.value_size, (ssize_t)sz);
2067				return -EINVAL;
2068			}
2069			map->def.value_size = sz;
2070			map->btf_value_type_id = t->type;
2071		}
2072		else if (strcmp(name, "values") == 0) {
2073			int err;
2074
2075			if (is_inner) {
2076				pr_warn("map '%s': multi-level inner maps not supported.\n",
2077					map->name);
2078				return -ENOTSUP;
2079			}
2080			if (i != vlen - 1) {
2081				pr_warn("map '%s': '%s' member should be last.\n",
2082					map->name, name);
2083				return -EINVAL;
2084			}
2085			if (!bpf_map_type__is_map_in_map(map->def.type)) {
2086				pr_warn("map '%s': should be map-in-map.\n",
2087					map->name);
2088				return -ENOTSUP;
2089			}
2090			if (map->def.value_size && map->def.value_size != 4) {
2091				pr_warn("map '%s': conflicting value size %u != 4.\n",
2092					map->name, map->def.value_size);
2093				return -EINVAL;
2094			}
2095			map->def.value_size = 4;
2096			t = btf__type_by_id(obj->btf, m->type);
2097			if (!t) {
2098				pr_warn("map '%s': map-in-map inner type [%d] not found.\n",
2099					map->name, m->type);
2100				return -EINVAL;
2101			}
2102			if (!btf_is_array(t) || btf_array(t)->nelems) {
2103				pr_warn("map '%s': map-in-map inner spec is not a zero-sized array.\n",
2104					map->name);
2105				return -EINVAL;
2106			}
2107			t = skip_mods_and_typedefs(obj->btf, btf_array(t)->type,
2108						   NULL);
2109			if (!btf_is_ptr(t)) {
2110				pr_warn("map '%s': map-in-map inner def is of unexpected kind %u.\n",
2111					map->name, btf_kind(t));
2112				return -EINVAL;
2113			}
2114			t = skip_mods_and_typedefs(obj->btf, t->type, NULL);
2115			if (!btf_is_struct(t)) {
2116				pr_warn("map '%s': map-in-map inner def is of unexpected kind %u.\n",
2117					map->name, btf_kind(t));
2118				return -EINVAL;
2119			}
2120
2121			map->inner_map = calloc(1, sizeof(*map->inner_map));
2122			if (!map->inner_map)
2123				return -ENOMEM;
2124			map->inner_map->sec_idx = obj->efile.btf_maps_shndx;
2125			map->inner_map->name = malloc(strlen(map->name) +
2126						      sizeof(".inner") + 1);
2127			if (!map->inner_map->name)
2128				return -ENOMEM;
2129			sprintf(map->inner_map->name, "%s.inner", map->name);
2130
2131			err = parse_btf_map_def(obj, map->inner_map, t, strict,
2132						true /* is_inner */, NULL);
2133			if (err)
2134				return err;
2135		} else if (strcmp(name, "pinning") == 0) {
2136			__u32 val;
2137			int err;
2138
2139			if (is_inner) {
2140				pr_debug("map '%s': inner def can't be pinned.\n",
2141					 map->name);
2142				return -EINVAL;
2143			}
2144			if (!get_map_field_int(map->name, obj->btf, m, &val))
2145				return -EINVAL;
2146			pr_debug("map '%s': found pinning = %u.\n",
2147				 map->name, val);
2148
2149			if (val != LIBBPF_PIN_NONE &&
2150			    val != LIBBPF_PIN_BY_NAME) {
2151				pr_warn("map '%s': invalid pinning value %u.\n",
2152					map->name, val);
2153				return -EINVAL;
2154			}
2155			if (val == LIBBPF_PIN_BY_NAME) {
2156				err = build_map_pin_path(map, pin_root_path);
2157				if (err) {
2158					pr_warn("map '%s': couldn't build pin path.\n",
2159						map->name);
2160					return err;
2161				}
2162			}
2163		} else {
2164			if (strict) {
2165				pr_warn("map '%s': unknown field '%s'.\n",
2166					map->name, name);
2167				return -ENOTSUP;
2168			}
2169			pr_debug("map '%s': ignoring unknown field '%s'.\n",
2170				 map->name, name);
2171		}
2172	}
2173
2174	if (map->def.type == BPF_MAP_TYPE_UNSPEC) {
2175		pr_warn("map '%s': map type isn't specified.\n", map->name);
2176		return -EINVAL;
2177	}
2178
2179	return 0;
2180}
2181
2182static int bpf_object__init_user_btf_map(struct bpf_object *obj,
2183					 const struct btf_type *sec,
2184					 int var_idx, int sec_idx,
2185					 const Elf_Data *data, bool strict,
2186					 const char *pin_root_path)
2187{
2188	const struct btf_type *var, *def;
2189	const struct btf_var_secinfo *vi;
2190	const struct btf_var *var_extra;
2191	const char *map_name;
2192	struct bpf_map *map;
2193
2194	vi = btf_var_secinfos(sec) + var_idx;
2195	var = btf__type_by_id(obj->btf, vi->type);
2196	var_extra = btf_var(var);
2197	map_name = btf__name_by_offset(obj->btf, var->name_off);
2198
2199	if (map_name == NULL || map_name[0] == '\0') {
2200		pr_warn("map #%d: empty name.\n", var_idx);
2201		return -EINVAL;
2202	}
2203	if ((__u64)vi->offset + vi->size > data->d_size) {
2204		pr_warn("map '%s' BTF data is corrupted.\n", map_name);
2205		return -EINVAL;
2206	}
2207	if (!btf_is_var(var)) {
2208		pr_warn("map '%s': unexpected var kind %u.\n",
2209			map_name, btf_kind(var));
2210		return -EINVAL;
2211	}
2212	if (var_extra->linkage != BTF_VAR_GLOBAL_ALLOCATED &&
2213	    var_extra->linkage != BTF_VAR_STATIC) {
2214		pr_warn("map '%s': unsupported var linkage %u.\n",
2215			map_name, var_extra->linkage);
2216		return -EOPNOTSUPP;
2217	}
2218
2219	def = skip_mods_and_typedefs(obj->btf, var->type, NULL);
2220	if (!btf_is_struct(def)) {
2221		pr_warn("map '%s': unexpected def kind %u.\n",
2222			map_name, btf_kind(var));
2223		return -EINVAL;
2224	}
2225	if (def->size > vi->size) {
2226		pr_warn("map '%s': invalid def size.\n", map_name);
2227		return -EINVAL;
2228	}
2229
2230	map = bpf_object__add_map(obj);
2231	if (IS_ERR(map))
2232		return PTR_ERR(map);
2233	map->name = strdup(map_name);
2234	if (!map->name) {
2235		pr_warn("map '%s': failed to alloc map name.\n", map_name);
2236		return -ENOMEM;
2237	}
2238	map->libbpf_type = LIBBPF_MAP_UNSPEC;
2239	map->def.type = BPF_MAP_TYPE_UNSPEC;
2240	map->sec_idx = sec_idx;
2241	map->sec_offset = vi->offset;
2242	map->btf_var_idx = var_idx;
2243	pr_debug("map '%s': at sec_idx %d, offset %zu.\n",
2244		 map_name, map->sec_idx, map->sec_offset);
2245
2246	return parse_btf_map_def(obj, map, def, strict, false, pin_root_path);
2247}
2248
2249static int bpf_object__init_user_btf_maps(struct bpf_object *obj, bool strict,
2250					  const char *pin_root_path)
2251{
2252	const struct btf_type *sec = NULL;
2253	int nr_types, i, vlen, err;
2254	const struct btf_type *t;
2255	const char *name;
2256	Elf_Data *data;
2257	Elf_Scn *scn;
2258
2259	if (obj->efile.btf_maps_shndx < 0)
2260		return 0;
2261
2262	scn = elf_getscn(obj->efile.elf, obj->efile.btf_maps_shndx);
2263	if (scn)
2264		data = elf_getdata(scn, NULL);
2265	if (!scn || !data) {
2266		pr_warn("failed to get Elf_Data from map section %d (%s)\n",
2267			obj->efile.btf_maps_shndx, MAPS_ELF_SEC);
2268		return -EINVAL;
2269	}
2270
2271	nr_types = btf__get_nr_types(obj->btf);
2272	for (i = 1; i <= nr_types; i++) {
2273		t = btf__type_by_id(obj->btf, i);
2274		if (!btf_is_datasec(t))
2275			continue;
2276		name = btf__name_by_offset(obj->btf, t->name_off);
2277		if (strcmp(name, MAPS_ELF_SEC) == 0) {
2278			sec = t;
2279			obj->efile.btf_maps_sec_btf_id = i;
2280			break;
2281		}
2282	}
2283
2284	if (!sec) {
2285		pr_warn("DATASEC '%s' not found.\n", MAPS_ELF_SEC);
2286		return -ENOENT;
2287	}
2288
2289	vlen = btf_vlen(sec);
2290	for (i = 0; i < vlen; i++) {
2291		err = bpf_object__init_user_btf_map(obj, sec, i,
2292						    obj->efile.btf_maps_shndx,
2293						    data, strict,
2294						    pin_root_path);
2295		if (err)
2296			return err;
2297	}
2298
2299	return 0;
2300}
2301
2302static int bpf_object__init_maps(struct bpf_object *obj,
2303				 const struct bpf_object_open_opts *opts)
2304{
2305	const char *pin_root_path;
2306	bool strict;
2307	int err;
2308
2309	strict = !OPTS_GET(opts, relaxed_maps, false);
2310	pin_root_path = OPTS_GET(opts, pin_root_path, NULL);
2311
2312	err = bpf_object__init_user_maps(obj, strict);
2313	err = err ?: bpf_object__init_user_btf_maps(obj, strict, pin_root_path);
2314	err = err ?: bpf_object__init_global_data_maps(obj);
2315	err = err ?: bpf_object__init_kconfig_map(obj);
2316	err = err ?: bpf_object__init_struct_ops_maps(obj);
2317	if (err)
2318		return err;
2319
2320	return 0;
2321}
2322
2323static bool section_have_execinstr(struct bpf_object *obj, int idx)
2324{
2325	Elf_Scn *scn;
2326	GElf_Shdr sh;
2327
2328	scn = elf_getscn(obj->efile.elf, idx);
2329	if (!scn)
2330		return false;
2331
2332	if (gelf_getshdr(scn, &sh) != &sh)
2333		return false;
2334
2335	if (sh.sh_flags & SHF_EXECINSTR)
2336		return true;
2337
2338	return false;
2339}
2340
2341static bool btf_needs_sanitization(struct bpf_object *obj)
2342{
2343	bool has_func_global = obj->caps.btf_func_global;
2344	bool has_datasec = obj->caps.btf_datasec;
2345	bool has_func = obj->caps.btf_func;
2346
2347	return !has_func || !has_datasec || !has_func_global;
2348}
2349
2350static void bpf_object__sanitize_btf(struct bpf_object *obj, struct btf *btf)
2351{
2352	bool has_func_global = obj->caps.btf_func_global;
2353	bool has_datasec = obj->caps.btf_datasec;
2354	bool has_func = obj->caps.btf_func;
2355	struct btf_type *t;
2356	int i, j, vlen;
2357
2358	for (i = 1; i <= btf__get_nr_types(btf); i++) {
2359		t = (struct btf_type *)btf__type_by_id(btf, i);
2360
2361		if (!has_datasec && btf_is_var(t)) {
2362			/* replace VAR with INT */
2363			t->info = BTF_INFO_ENC(BTF_KIND_INT, 0, 0);
2364			/*
2365			 * using size = 1 is the safest choice, 4 will be too
2366			 * big and cause kernel BTF validation failure if
2367			 * original variable took less than 4 bytes
2368			 */
2369			t->size = 1;
2370			*(int *)(t + 1) = BTF_INT_ENC(0, 0, 8);
2371		} else if (!has_datasec && btf_is_datasec(t)) {
2372			/* replace DATASEC with STRUCT */
2373			const struct btf_var_secinfo *v = btf_var_secinfos(t);
2374			struct btf_member *m = btf_members(t);
2375			struct btf_type *vt;
2376			char *name;
2377
2378			name = (char *)btf__name_by_offset(btf, t->name_off);
2379			while (*name) {
2380				if (*name == '.')
2381					*name = '_';
2382				name++;
2383			}
2384
2385			vlen = btf_vlen(t);
2386			t->info = BTF_INFO_ENC(BTF_KIND_STRUCT, 0, vlen);
2387			for (j = 0; j < vlen; j++, v++, m++) {
2388				/* order of field assignments is important */
2389				m->offset = v->offset * 8;
2390				m->type = v->type;
2391				/* preserve variable name as member name */
2392				vt = (void *)btf__type_by_id(btf, v->type);
2393				m->name_off = vt->name_off;
2394			}
2395		} else if (!has_func && btf_is_func_proto(t)) {
2396			/* replace FUNC_PROTO with ENUM */
2397			vlen = btf_vlen(t);
2398			t->info = BTF_INFO_ENC(BTF_KIND_ENUM, 0, vlen);
2399			t->size = sizeof(__u32); /* kernel enforced */
2400		} else if (!has_func && btf_is_func(t)) {
2401			/* replace FUNC with TYPEDEF */
2402			t->info = BTF_INFO_ENC(BTF_KIND_TYPEDEF, 0, 0);
2403		} else if (!has_func_global && btf_is_func(t)) {
2404			/* replace BTF_FUNC_GLOBAL with BTF_FUNC_STATIC */
2405			t->info = BTF_INFO_ENC(BTF_KIND_FUNC, 0, 0);
2406		}
2407	}
2408}
2409
2410static bool libbpf_needs_btf(const struct bpf_object *obj)
2411{
2412	return obj->efile.btf_maps_shndx >= 0 ||
2413	       obj->efile.st_ops_shndx >= 0 ||
2414	       obj->nr_extern > 0;
2415}
2416
2417static bool kernel_needs_btf(const struct bpf_object *obj)
2418{
2419	return obj->efile.st_ops_shndx >= 0;
2420}
2421
2422static int bpf_object__init_btf(struct bpf_object *obj,
2423				Elf_Data *btf_data,
2424				Elf_Data *btf_ext_data)
2425{
2426	int err = -ENOENT;
2427
2428	if (btf_data) {
2429		obj->btf = btf__new(btf_data->d_buf, btf_data->d_size);
2430		if (IS_ERR(obj->btf)) {
2431			err = PTR_ERR(obj->btf);
2432			obj->btf = NULL;
2433			pr_warn("Error loading ELF section %s: %d.\n",
2434				BTF_ELF_SEC, err);
2435			goto out;
2436		}
2437		/* enforce 8-byte pointers for BPF-targeted BTFs */
2438		btf__set_pointer_size(obj->btf, 8);
2439		err = 0;
2440	}
2441	if (btf_ext_data) {
2442		if (!obj->btf) {
2443			pr_debug("Ignore ELF section %s because its depending ELF section %s is not found.\n",
2444				 BTF_EXT_ELF_SEC, BTF_ELF_SEC);
2445			goto out;
2446		}
2447		obj->btf_ext = btf_ext__new(btf_ext_data->d_buf,
2448					    btf_ext_data->d_size);
2449		if (IS_ERR(obj->btf_ext)) {
2450			pr_warn("Error loading ELF section %s: %ld. Ignored and continue.\n",
2451				BTF_EXT_ELF_SEC, PTR_ERR(obj->btf_ext));
2452			obj->btf_ext = NULL;
2453			goto out;
2454		}
2455	}
2456out:
2457	if (err && libbpf_needs_btf(obj)) {
2458		pr_warn("BTF is required, but is missing or corrupted.\n");
2459		return err;
2460	}
2461	return 0;
2462}
2463
2464static int bpf_object__finalize_btf(struct bpf_object *obj)
2465{
2466	int err;
2467
2468	if (!obj->btf)
2469		return 0;
2470
2471	err = btf__finalize_data(obj, obj->btf);
2472	if (err) {
2473		pr_warn("Error finalizing %s: %d.\n", BTF_ELF_SEC, err);
2474		return err;
2475	}
2476
2477	return 0;
2478}
2479
2480static inline bool libbpf_prog_needs_vmlinux_btf(struct bpf_program *prog)
2481{
2482	if (prog->type == BPF_PROG_TYPE_STRUCT_OPS ||
2483	    prog->type == BPF_PROG_TYPE_LSM)
2484		return true;
2485
2486	/* BPF_PROG_TYPE_TRACING programs which do not attach to other programs
2487	 * also need vmlinux BTF
2488	 */
2489	if (prog->type == BPF_PROG_TYPE_TRACING && !prog->attach_prog_fd)
2490		return true;
2491
2492	return false;
2493}
2494
2495static int bpf_object__load_vmlinux_btf(struct bpf_object *obj)
2496{
2497	bool need_vmlinux_btf = false;
2498	struct bpf_program *prog;
2499	int err;
2500
2501	/* CO-RE relocations need kernel BTF */
2502	if (obj->btf_ext && obj->btf_ext->field_reloc_info.len)
2503		need_vmlinux_btf = true;
2504
2505	bpf_object__for_each_program(prog, obj) {
2506		if (!prog->load)
2507			continue;
2508		if (libbpf_prog_needs_vmlinux_btf(prog)) {
2509			need_vmlinux_btf = true;
2510			break;
2511		}
2512	}
2513
2514	if (!need_vmlinux_btf)
2515		return 0;
2516
2517	obj->btf_vmlinux = libbpf_find_kernel_btf();
2518	if (IS_ERR(obj->btf_vmlinux)) {
2519		err = PTR_ERR(obj->btf_vmlinux);
2520		pr_warn("Error loading vmlinux BTF: %d\n", err);
2521		obj->btf_vmlinux = NULL;
2522		return err;
2523	}
2524	return 0;
2525}
2526
2527static int bpf_object__sanitize_and_load_btf(struct bpf_object *obj)
2528{
2529	struct btf *kern_btf = obj->btf;
2530	bool btf_mandatory, sanitize;
2531	int err = 0;
2532
2533	if (!obj->btf)
2534		return 0;
2535
2536	sanitize = btf_needs_sanitization(obj);
2537	if (sanitize) {
2538		const void *raw_data;
2539		__u32 sz;
2540
2541		/* clone BTF to sanitize a copy and leave the original intact */
2542		raw_data = btf__get_raw_data(obj->btf, &sz);
2543		kern_btf = btf__new(raw_data, sz);
2544		if (IS_ERR(kern_btf))
2545			return PTR_ERR(kern_btf);
2546
2547		/* enforce 8-byte pointers for BPF-targeted BTFs */
2548		btf__set_pointer_size(obj->btf, 8);
2549		bpf_object__sanitize_btf(obj, kern_btf);
2550	}
2551
2552	err = btf__load(kern_btf);
2553	if (sanitize) {
2554		if (!err) {
2555			/* move fd to libbpf's BTF */
2556			btf__set_fd(obj->btf, btf__fd(kern_btf));
2557			btf__set_fd(kern_btf, -1);
2558		}
2559		btf__free(kern_btf);
2560	}
2561	if (err) {
2562		btf_mandatory = kernel_needs_btf(obj);
2563		pr_warn("Error loading .BTF into kernel: %d. %s\n", err,
2564			btf_mandatory ? "BTF is mandatory, can't proceed."
2565				      : "BTF is optional, ignoring.");
2566		if (!btf_mandatory)
2567			err = 0;
2568	}
2569	return err;
2570}
2571
2572static int bpf_object__elf_collect(struct bpf_object *obj)
2573{
2574	Elf *elf = obj->efile.elf;
2575	GElf_Ehdr *ep = &obj->efile.ehdr;
2576	Elf_Data *btf_ext_data = NULL;
2577	Elf_Data *btf_data = NULL;
2578	Elf_Scn *scn = NULL;
2579	int idx = 0, err = 0;
2580
2581	/* Elf is corrupted/truncated, avoid calling elf_strptr. */
2582	if (!elf_rawdata(elf_getscn(elf, ep->e_shstrndx), NULL)) {
2583		pr_warn("failed to get e_shstrndx from %s\n", obj->path);
 
2584		return -LIBBPF_ERRNO__FORMAT;
2585	}
2586
2587	while ((scn = elf_nextscn(elf, scn)) != NULL) {
2588		char *name;
2589		GElf_Shdr sh;
2590		Elf_Data *data;
2591
2592		idx++;
2593		if (gelf_getshdr(scn, &sh) != &sh) {
2594			pr_warn("failed to get section(%d) header from %s\n",
2595				idx, obj->path);
2596			return -LIBBPF_ERRNO__FORMAT;
 
2597		}
2598
2599		name = elf_strptr(elf, ep->e_shstrndx, sh.sh_name);
2600		if (!name) {
2601			pr_warn("failed to get section(%d) name from %s\n",
2602				idx, obj->path);
2603			return -LIBBPF_ERRNO__FORMAT;
 
2604		}
2605
2606		data = elf_getdata(scn, 0);
2607		if (!data) {
2608			pr_warn("failed to get section(%d) data from %s(%s)\n",
2609				idx, name, obj->path);
2610			return -LIBBPF_ERRNO__FORMAT;
 
2611		}
2612		pr_debug("section(%d) %s, size %ld, link %d, flags %lx, type=%d\n",
2613			 idx, name, (unsigned long)data->d_size,
2614			 (int)sh.sh_link, (unsigned long)sh.sh_flags,
2615			 (int)sh.sh_type);
2616
2617		if (strcmp(name, "license") == 0) {
2618			err = bpf_object__init_license(obj,
2619						       data->d_buf,
2620						       data->d_size);
2621			if (err)
2622				return err;
2623		} else if (strcmp(name, "version") == 0) {
2624			err = bpf_object__init_kversion(obj,
2625							data->d_buf,
2626							data->d_size);
2627			if (err)
2628				return err;
2629		} else if (strcmp(name, "maps") == 0) {
2630			obj->efile.maps_shndx = idx;
2631		} else if (strcmp(name, MAPS_ELF_SEC) == 0) {
2632			obj->efile.btf_maps_shndx = idx;
2633		} else if (strcmp(name, BTF_ELF_SEC) == 0) {
2634			btf_data = data;
2635		} else if (strcmp(name, BTF_EXT_ELF_SEC) == 0) {
2636			btf_ext_data = data;
2637		} else if (sh.sh_type == SHT_SYMTAB) {
2638			if (obj->efile.symbols) {
2639				pr_warn("bpf: multiple SYMTAB in %s\n",
2640					obj->path);
2641				return -LIBBPF_ERRNO__FORMAT;
2642			}
2643			obj->efile.symbols = data;
2644			obj->efile.symbols_shndx = idx;
2645			obj->efile.strtabidx = sh.sh_link;
2646		} else if (sh.sh_type == SHT_PROGBITS && data->d_size > 0) {
2647			if (sh.sh_flags & SHF_EXECINSTR) {
2648				if (strcmp(name, ".text") == 0)
2649					obj->efile.text_shndx = idx;
2650				err = bpf_object__add_program(obj, data->d_buf,
2651							      data->d_size,
2652							      name, idx);
2653				if (err) {
2654					char errmsg[STRERR_BUFSIZE];
2655					char *cp;
2656
2657					cp = libbpf_strerror_r(-err, errmsg,
2658							       sizeof(errmsg));
2659					pr_warn("failed to alloc program %s (%s): %s",
2660						name, obj->path, cp);
2661					return err;
2662				}
2663			} else if (strcmp(name, DATA_SEC) == 0) {
2664				obj->efile.data = data;
2665				obj->efile.data_shndx = idx;
2666			} else if (strcmp(name, RODATA_SEC) == 0) {
2667				obj->efile.rodata = data;
2668				obj->efile.rodata_shndx = idx;
2669			} else if (strcmp(name, STRUCT_OPS_SEC) == 0) {
2670				obj->efile.st_ops_data = data;
2671				obj->efile.st_ops_shndx = idx;
2672			} else {
2673				pr_debug("skip section(%d) %s\n", idx, name);
2674			}
2675		} else if (sh.sh_type == SHT_REL) {
2676			int nr_sects = obj->efile.nr_reloc_sects;
2677			void *sects = obj->efile.reloc_sects;
2678			int sec = sh.sh_info; /* points to other section */
2679
2680			/* Only do relo for section with exec instructions */
2681			if (!section_have_execinstr(obj, sec) &&
2682			    strcmp(name, ".rel" STRUCT_OPS_SEC) &&
2683			    strcmp(name, ".rel" MAPS_ELF_SEC)) {
2684				pr_debug("skip relo %s(%d) for section(%d)\n",
2685					 name, idx, sec);
2686				continue;
2687			}
2688
2689			sects = reallocarray(sects, nr_sects + 1,
2690					     sizeof(*obj->efile.reloc_sects));
2691			if (!sects) {
2692				pr_warn("reloc_sects realloc failed\n");
2693				return -ENOMEM;
2694			}
2695
2696			obj->efile.reloc_sects = sects;
2697			obj->efile.nr_reloc_sects++;
2698
2699			obj->efile.reloc_sects[nr_sects].shdr = sh;
2700			obj->efile.reloc_sects[nr_sects].data = data;
2701		} else if (sh.sh_type == SHT_NOBITS &&
2702			   strcmp(name, BSS_SEC) == 0) {
2703			obj->efile.bss = data;
2704			obj->efile.bss_shndx = idx;
2705		} else {
2706			pr_debug("skip section(%d) %s\n", idx, name);
2707		}
2708	}
2709
2710	if (!obj->efile.strtabidx || obj->efile.strtabidx > idx) {
2711		pr_warn("Corrupted ELF file: index of strtab invalid\n");
2712		return -LIBBPF_ERRNO__FORMAT;
2713	}
2714	return bpf_object__init_btf(obj, btf_data, btf_ext_data);
2715}
2716
2717static bool sym_is_extern(const GElf_Sym *sym)
2718{
2719	int bind = GELF_ST_BIND(sym->st_info);
2720	/* externs are symbols w/ type=NOTYPE, bind=GLOBAL|WEAK, section=UND */
2721	return sym->st_shndx == SHN_UNDEF &&
2722	       (bind == STB_GLOBAL || bind == STB_WEAK) &&
2723	       GELF_ST_TYPE(sym->st_info) == STT_NOTYPE;
2724}
2725
2726static int find_extern_btf_id(const struct btf *btf, const char *ext_name)
2727{
2728	const struct btf_type *t;
2729	const char *var_name;
2730	int i, n;
2731
2732	if (!btf)
2733		return -ESRCH;
2734
2735	n = btf__get_nr_types(btf);
2736	for (i = 1; i <= n; i++) {
2737		t = btf__type_by_id(btf, i);
2738
2739		if (!btf_is_var(t))
2740			continue;
2741
2742		var_name = btf__name_by_offset(btf, t->name_off);
2743		if (strcmp(var_name, ext_name))
2744			continue;
2745
2746		if (btf_var(t)->linkage != BTF_VAR_GLOBAL_EXTERN)
2747			return -EINVAL;
2748
2749		return i;
2750	}
2751
2752	return -ENOENT;
2753}
2754
2755static int find_extern_sec_btf_id(struct btf *btf, int ext_btf_id) {
2756	const struct btf_var_secinfo *vs;
2757	const struct btf_type *t;
2758	int i, j, n;
2759
2760	if (!btf)
2761		return -ESRCH;
2762
2763	n = btf__get_nr_types(btf);
2764	for (i = 1; i <= n; i++) {
2765		t = btf__type_by_id(btf, i);
2766
2767		if (!btf_is_datasec(t))
2768			continue;
2769
2770		vs = btf_var_secinfos(t);
2771		for (j = 0; j < btf_vlen(t); j++, vs++) {
2772			if (vs->type == ext_btf_id)
2773				return i;
2774		}
2775	}
2776
2777	return -ENOENT;
2778}
2779
2780static enum kcfg_type find_kcfg_type(const struct btf *btf, int id,
2781				     bool *is_signed)
2782{
2783	const struct btf_type *t;
2784	const char *name;
2785
2786	t = skip_mods_and_typedefs(btf, id, NULL);
2787	name = btf__name_by_offset(btf, t->name_off);
2788
2789	if (is_signed)
2790		*is_signed = false;
2791	switch (btf_kind(t)) {
2792	case BTF_KIND_INT: {
2793		int enc = btf_int_encoding(t);
2794
2795		if (enc & BTF_INT_BOOL)
2796			return t->size == 1 ? KCFG_BOOL : KCFG_UNKNOWN;
2797		if (is_signed)
2798			*is_signed = enc & BTF_INT_SIGNED;
2799		if (t->size == 1)
2800			return KCFG_CHAR;
2801		if (t->size < 1 || t->size > 8 || (t->size & (t->size - 1)))
2802			return KCFG_UNKNOWN;
2803		return KCFG_INT;
2804	}
2805	case BTF_KIND_ENUM:
2806		if (t->size != 4)
2807			return KCFG_UNKNOWN;
2808		if (strcmp(name, "libbpf_tristate"))
2809			return KCFG_UNKNOWN;
2810		return KCFG_TRISTATE;
2811	case BTF_KIND_ARRAY:
2812		if (btf_array(t)->nelems == 0)
2813			return KCFG_UNKNOWN;
2814		if (find_kcfg_type(btf, btf_array(t)->type, NULL) != KCFG_CHAR)
2815			return KCFG_UNKNOWN;
2816		return KCFG_CHAR_ARR;
2817	default:
2818		return KCFG_UNKNOWN;
2819	}
2820}
2821
2822static int cmp_externs(const void *_a, const void *_b)
2823{
2824	const struct extern_desc *a = _a;
2825	const struct extern_desc *b = _b;
2826
2827	if (a->type != b->type)
2828		return a->type < b->type ? -1 : 1;
2829
2830	if (a->type == EXT_KCFG) {
2831		/* descending order by alignment requirements */
2832		if (a->kcfg.align != b->kcfg.align)
2833			return a->kcfg.align > b->kcfg.align ? -1 : 1;
2834		/* ascending order by size, within same alignment class */
2835		if (a->kcfg.sz != b->kcfg.sz)
2836			return a->kcfg.sz < b->kcfg.sz ? -1 : 1;
2837	}
2838
2839	/* resolve ties by name */
2840	return strcmp(a->name, b->name);
2841}
2842
2843static int find_int_btf_id(const struct btf *btf)
2844{
2845	const struct btf_type *t;
2846	int i, n;
2847
2848	n = btf__get_nr_types(btf);
2849	for (i = 1; i <= n; i++) {
2850		t = btf__type_by_id(btf, i);
2851
2852		if (btf_is_int(t) && btf_int_bits(t) == 32)
2853			return i;
2854	}
2855
2856	return 0;
2857}
2858
2859static int bpf_object__collect_externs(struct bpf_object *obj)
2860{
2861	struct btf_type *sec, *kcfg_sec = NULL, *ksym_sec = NULL;
2862	const struct btf_type *t;
2863	struct extern_desc *ext;
2864	int i, n, off;
2865	const char *ext_name, *sec_name;
2866	Elf_Scn *scn;
2867	GElf_Shdr sh;
2868
2869	if (!obj->efile.symbols)
2870		return 0;
2871
2872	scn = elf_getscn(obj->efile.elf, obj->efile.symbols_shndx);
2873	if (!scn)
2874		return -LIBBPF_ERRNO__FORMAT;
2875	if (gelf_getshdr(scn, &sh) != &sh)
2876		return -LIBBPF_ERRNO__FORMAT;
2877	n = sh.sh_size / sh.sh_entsize;
2878
2879	pr_debug("looking for externs among %d symbols...\n", n);
2880	for (i = 0; i < n; i++) {
2881		GElf_Sym sym;
2882
2883		if (!gelf_getsym(obj->efile.symbols, i, &sym))
2884			return -LIBBPF_ERRNO__FORMAT;
2885		if (!sym_is_extern(&sym))
2886			continue;
2887		ext_name = elf_strptr(obj->efile.elf, obj->efile.strtabidx,
2888				      sym.st_name);
2889		if (!ext_name || !ext_name[0])
2890			continue;
2891
2892		ext = obj->externs;
2893		ext = reallocarray(ext, obj->nr_extern + 1, sizeof(*ext));
2894		if (!ext)
2895			return -ENOMEM;
2896		obj->externs = ext;
2897		ext = &ext[obj->nr_extern];
2898		memset(ext, 0, sizeof(*ext));
2899		obj->nr_extern++;
2900
2901		ext->btf_id = find_extern_btf_id(obj->btf, ext_name);
2902		if (ext->btf_id <= 0) {
2903			pr_warn("failed to find BTF for extern '%s': %d\n",
2904				ext_name, ext->btf_id);
2905			return ext->btf_id;
2906		}
2907		t = btf__type_by_id(obj->btf, ext->btf_id);
2908		ext->name = btf__name_by_offset(obj->btf, t->name_off);
2909		ext->sym_idx = i;
2910		ext->is_weak = GELF_ST_BIND(sym.st_info) == STB_WEAK;
2911
2912		ext->sec_btf_id = find_extern_sec_btf_id(obj->btf, ext->btf_id);
2913		if (ext->sec_btf_id <= 0) {
2914			pr_warn("failed to find BTF for extern '%s' [%d] section: %d\n",
2915				ext_name, ext->btf_id, ext->sec_btf_id);
2916			return ext->sec_btf_id;
2917		}
2918		sec = (void *)btf__type_by_id(obj->btf, ext->sec_btf_id);
2919		sec_name = btf__name_by_offset(obj->btf, sec->name_off);
2920
2921		if (strcmp(sec_name, KCONFIG_SEC) == 0) {
2922			kcfg_sec = sec;
2923			ext->type = EXT_KCFG;
2924			ext->kcfg.sz = btf__resolve_size(obj->btf, t->type);
2925			if (ext->kcfg.sz <= 0) {
2926				pr_warn("failed to resolve size of extern (kcfg) '%s': %d\n",
2927					ext_name, ext->kcfg.sz);
2928				return ext->kcfg.sz;
2929			}
2930			ext->kcfg.align = btf__align_of(obj->btf, t->type);
2931			if (ext->kcfg.align <= 0) {
2932				pr_warn("failed to determine alignment of extern (kcfg) '%s': %d\n",
2933					ext_name, ext->kcfg.align);
2934				return -EINVAL;
2935			}
2936			ext->kcfg.type = find_kcfg_type(obj->btf, t->type,
2937						        &ext->kcfg.is_signed);
2938			if (ext->kcfg.type == KCFG_UNKNOWN) {
2939				pr_warn("extern (kcfg) '%s' type is unsupported\n", ext_name);
2940				return -ENOTSUP;
2941			}
2942		} else if (strcmp(sec_name, KSYMS_SEC) == 0) {
2943			const struct btf_type *vt;
2944
2945			ksym_sec = sec;
2946			ext->type = EXT_KSYM;
 
 
2947
2948			vt = skip_mods_and_typedefs(obj->btf, t->type, NULL);
2949			if (!btf_is_void(vt)) {
2950				pr_warn("extern (ksym) '%s' is not typeless (void)\n", ext_name);
2951				return -ENOTSUP;
2952			}
2953		} else {
2954			pr_warn("unrecognized extern section '%s'\n", sec_name);
2955			return -ENOTSUP;
2956		}
2957	}
2958	pr_debug("collected %d externs total\n", obj->nr_extern);
2959
2960	if (!obj->nr_extern)
2961		return 0;
2962
2963	/* sort externs by type, for kcfg ones also by (align, size, name) */
2964	qsort(obj->externs, obj->nr_extern, sizeof(*ext), cmp_externs);
2965
2966	/* for .ksyms section, we need to turn all externs into allocated
2967	 * variables in BTF to pass kernel verification; we do this by
2968	 * pretending that each extern is a 8-byte variable
2969	 */
2970	if (ksym_sec) {
2971		/* find existing 4-byte integer type in BTF to use for fake
2972		 * extern variables in DATASEC
2973		 */
2974		int int_btf_id = find_int_btf_id(obj->btf);
2975
2976		for (i = 0; i < obj->nr_extern; i++) {
2977			ext = &obj->externs[i];
2978			if (ext->type != EXT_KSYM)
2979				continue;
2980			pr_debug("extern (ksym) #%d: symbol %d, name %s\n",
2981				 i, ext->sym_idx, ext->name);
2982		}
2983
2984		sec = ksym_sec;
2985		n = btf_vlen(sec);
2986		for (i = 0, off = 0; i < n; i++, off += sizeof(int)) {
2987			struct btf_var_secinfo *vs = btf_var_secinfos(sec) + i;
2988			struct btf_type *vt;
2989
2990			vt = (void *)btf__type_by_id(obj->btf, vs->type);
2991			ext_name = btf__name_by_offset(obj->btf, vt->name_off);
2992			ext = find_extern_by_name(obj, ext_name);
2993			if (!ext) {
2994				pr_warn("failed to find extern definition for BTF var '%s'\n",
2995					ext_name);
2996				return -ESRCH;
2997			}
2998			btf_var(vt)->linkage = BTF_VAR_GLOBAL_ALLOCATED;
2999			vt->type = int_btf_id;
3000			vs->offset = off;
3001			vs->size = sizeof(int);
3002		}
3003		sec->size = off;
 
3004	}
3005
3006	if (kcfg_sec) {
3007		sec = kcfg_sec;
3008		/* for kcfg externs calculate their offsets within a .kconfig map */
3009		off = 0;
3010		for (i = 0; i < obj->nr_extern; i++) {
3011			ext = &obj->externs[i];
3012			if (ext->type != EXT_KCFG)
3013				continue;
3014
3015			ext->kcfg.data_off = roundup(off, ext->kcfg.align);
3016			off = ext->kcfg.data_off + ext->kcfg.sz;
3017			pr_debug("extern (kcfg) #%d: symbol %d, off %u, name %s\n",
3018				 i, ext->sym_idx, ext->kcfg.data_off, ext->name);
3019		}
3020		sec->size = off;
3021		n = btf_vlen(sec);
3022		for (i = 0; i < n; i++) {
3023			struct btf_var_secinfo *vs = btf_var_secinfos(sec) + i;
3024
3025			t = btf__type_by_id(obj->btf, vs->type);
3026			ext_name = btf__name_by_offset(obj->btf, t->name_off);
3027			ext = find_extern_by_name(obj, ext_name);
3028			if (!ext) {
3029				pr_warn("failed to find extern definition for BTF var '%s'\n",
3030					ext_name);
3031				return -ESRCH;
3032			}
3033			btf_var(t)->linkage = BTF_VAR_GLOBAL_ALLOCATED;
3034			vs->offset = ext->kcfg.data_off;
3035		}
3036	}
3037	return 0;
 
 
 
3038}
3039
3040static struct bpf_program *
3041bpf_object__find_prog_by_idx(struct bpf_object *obj, int idx)
3042{
3043	struct bpf_program *prog;
3044	size_t i;
3045
3046	for (i = 0; i < obj->nr_programs; i++) {
3047		prog = &obj->programs[i];
3048		if (prog->idx == idx)
3049			return prog;
3050	}
3051	return NULL;
3052}
3053
3054struct bpf_program *
3055bpf_object__find_program_by_title(const struct bpf_object *obj,
3056				  const char *title)
3057{
3058	struct bpf_program *pos;
3059
3060	bpf_object__for_each_program(pos, obj) {
3061		if (pos->section_name && !strcmp(pos->section_name, title))
3062			return pos;
3063	}
3064	return NULL;
3065}
3066
3067struct bpf_program *
3068bpf_object__find_program_by_name(const struct bpf_object *obj,
3069				 const char *name)
3070{
3071	struct bpf_program *prog;
3072
3073	bpf_object__for_each_program(prog, obj) {
3074		if (!strcmp(prog->name, name))
3075			return prog;
3076	}
3077	return NULL;
3078}
3079
3080static bool bpf_object__shndx_is_data(const struct bpf_object *obj,
3081				      int shndx)
3082{
3083	return shndx == obj->efile.data_shndx ||
3084	       shndx == obj->efile.bss_shndx ||
3085	       shndx == obj->efile.rodata_shndx;
3086}
3087
3088static bool bpf_object__shndx_is_maps(const struct bpf_object *obj,
3089				      int shndx)
3090{
3091	return shndx == obj->efile.maps_shndx ||
3092	       shndx == obj->efile.btf_maps_shndx;
3093}
3094
3095static enum libbpf_map_type
3096bpf_object__section_to_libbpf_map_type(const struct bpf_object *obj, int shndx)
3097{
3098	if (shndx == obj->efile.data_shndx)
3099		return LIBBPF_MAP_DATA;
3100	else if (shndx == obj->efile.bss_shndx)
3101		return LIBBPF_MAP_BSS;
3102	else if (shndx == obj->efile.rodata_shndx)
3103		return LIBBPF_MAP_RODATA;
3104	else if (shndx == obj->efile.symbols_shndx)
3105		return LIBBPF_MAP_KCONFIG;
3106	else
3107		return LIBBPF_MAP_UNSPEC;
3108}
3109
3110static int bpf_program__record_reloc(struct bpf_program *prog,
3111				     struct reloc_desc *reloc_desc,
3112				     __u32 insn_idx, const char *name,
3113				     const GElf_Sym *sym, const GElf_Rel *rel)
3114{
3115	struct bpf_insn *insn = &prog->insns[insn_idx];
3116	size_t map_idx, nr_maps = prog->obj->nr_maps;
3117	struct bpf_object *obj = prog->obj;
3118	__u32 shdr_idx = sym->st_shndx;
3119	enum libbpf_map_type type;
3120	struct bpf_map *map;
3121
3122	/* sub-program call relocation */
3123	if (insn->code == (BPF_JMP | BPF_CALL)) {
3124		if (insn->src_reg != BPF_PSEUDO_CALL) {
3125			pr_warn("incorrect bpf_call opcode\n");
3126			return -LIBBPF_ERRNO__RELOC;
3127		}
3128		/* text_shndx can be 0, if no default "main" program exists */
3129		if (!shdr_idx || shdr_idx != obj->efile.text_shndx) {
3130			pr_warn("bad call relo against section %u\n", shdr_idx);
3131			return -LIBBPF_ERRNO__RELOC;
3132		}
3133		if (sym->st_value % 8) {
3134			pr_warn("bad call relo offset: %zu\n",
3135				(size_t)sym->st_value);
3136			return -LIBBPF_ERRNO__RELOC;
3137		}
3138		reloc_desc->type = RELO_CALL;
3139		reloc_desc->insn_idx = insn_idx;
3140		reloc_desc->sym_off = sym->st_value;
3141		obj->has_pseudo_calls = true;
3142		return 0;
3143	}
3144
3145	if (insn->code != (BPF_LD | BPF_IMM | BPF_DW)) {
3146		pr_warn("invalid relo for insns[%d].code 0x%x\n",
3147			insn_idx, insn->code);
3148		return -LIBBPF_ERRNO__RELOC;
3149	}
3150
3151	if (sym_is_extern(sym)) {
3152		int sym_idx = GELF_R_SYM(rel->r_info);
3153		int i, n = obj->nr_extern;
3154		struct extern_desc *ext;
3155
3156		for (i = 0; i < n; i++) {
3157			ext = &obj->externs[i];
3158			if (ext->sym_idx == sym_idx)
3159				break;
3160		}
3161		if (i >= n) {
3162			pr_warn("extern relo failed to find extern for sym %d\n",
3163				sym_idx);
3164			return -LIBBPF_ERRNO__RELOC;
3165		}
3166		pr_debug("found extern #%d '%s' (sym %d) for insn %u\n",
3167			 i, ext->name, ext->sym_idx, insn_idx);
3168		reloc_desc->type = RELO_EXTERN;
3169		reloc_desc->insn_idx = insn_idx;
3170		reloc_desc->sym_off = i; /* sym_off stores extern index */
3171		return 0;
3172	}
3173
3174	if (!shdr_idx || shdr_idx >= SHN_LORESERVE) {
3175		pr_warn("invalid relo for \'%s\' in special section 0x%x; forgot to initialize global var?..\n",
3176			name, shdr_idx);
3177		return -LIBBPF_ERRNO__RELOC;
3178	}
3179
3180	type = bpf_object__section_to_libbpf_map_type(obj, shdr_idx);
3181
3182	/* generic map reference relocation */
3183	if (type == LIBBPF_MAP_UNSPEC) {
3184		if (!bpf_object__shndx_is_maps(obj, shdr_idx)) {
3185			pr_warn("bad map relo against section %u\n",
3186				shdr_idx);
3187			return -LIBBPF_ERRNO__RELOC;
3188		}
3189		for (map_idx = 0; map_idx < nr_maps; map_idx++) {
3190			map = &obj->maps[map_idx];
3191			if (map->libbpf_type != type ||
3192			    map->sec_idx != sym->st_shndx ||
3193			    map->sec_offset != sym->st_value)
3194				continue;
3195			pr_debug("found map %zd (%s, sec %d, off %zu) for insn %u\n",
3196				 map_idx, map->name, map->sec_idx,
3197				 map->sec_offset, insn_idx);
3198			break;
3199		}
3200		if (map_idx >= nr_maps) {
3201			pr_warn("map relo failed to find map for sec %u, off %zu\n",
3202				shdr_idx, (size_t)sym->st_value);
3203			return -LIBBPF_ERRNO__RELOC;
3204		}
3205		reloc_desc->type = RELO_LD64;
3206		reloc_desc->insn_idx = insn_idx;
3207		reloc_desc->map_idx = map_idx;
3208		reloc_desc->sym_off = 0; /* sym->st_value determines map_idx */
3209		return 0;
3210	}
3211
3212	/* global data map relocation */
3213	if (!bpf_object__shndx_is_data(obj, shdr_idx)) {
3214		pr_warn("bad data relo against section %u\n", shdr_idx);
3215		return -LIBBPF_ERRNO__RELOC;
3216	}
3217	for (map_idx = 0; map_idx < nr_maps; map_idx++) {
3218		map = &obj->maps[map_idx];
3219		if (map->libbpf_type != type)
3220			continue;
3221		pr_debug("found data map %zd (%s, sec %d, off %zu) for insn %u\n",
3222			 map_idx, map->name, map->sec_idx, map->sec_offset,
3223			 insn_idx);
3224		break;
3225	}
3226	if (map_idx >= nr_maps) {
3227		pr_warn("data relo failed to find map for sec %u\n",
3228			shdr_idx);
3229		return -LIBBPF_ERRNO__RELOC;
3230	}
3231
3232	reloc_desc->type = RELO_DATA;
3233	reloc_desc->insn_idx = insn_idx;
3234	reloc_desc->map_idx = map_idx;
3235	reloc_desc->sym_off = sym->st_value;
3236	return 0;
3237}
3238
3239static int
3240bpf_program__collect_reloc(struct bpf_program *prog, GElf_Shdr *shdr,
3241			   Elf_Data *data, struct bpf_object *obj)
 
 
3242{
3243	Elf_Data *symbols = obj->efile.symbols;
3244	int err, i, nrels;
3245
3246	pr_debug("collecting relocating info for: '%s'\n", prog->section_name);
 
3247	nrels = shdr->sh_size / shdr->sh_entsize;
3248
3249	prog->reloc_desc = malloc(sizeof(*prog->reloc_desc) * nrels);
3250	if (!prog->reloc_desc) {
3251		pr_warn("failed to alloc memory in relocation\n");
3252		return -ENOMEM;
3253	}
3254	prog->nr_reloc = nrels;
3255
3256	for (i = 0; i < nrels; i++) {
3257		const char *name;
3258		__u32 insn_idx;
3259		GElf_Sym sym;
3260		GElf_Rel rel;
 
 
 
3261
3262		if (!gelf_getrel(data, i, &rel)) {
3263			pr_warn("relocation: failed to get %d reloc\n", i);
3264			return -LIBBPF_ERRNO__FORMAT;
3265		}
3266		if (!gelf_getsym(symbols, GELF_R_SYM(rel.r_info), &sym)) {
3267			pr_warn("relocation: symbol %"PRIx64" not found\n",
3268				GELF_R_SYM(rel.r_info));
 
 
 
3269			return -LIBBPF_ERRNO__FORMAT;
3270		}
3271		if (rel.r_offset % sizeof(struct bpf_insn))
3272			return -LIBBPF_ERRNO__FORMAT;
3273
3274		insn_idx = rel.r_offset / sizeof(struct bpf_insn);
3275		name = elf_strptr(obj->efile.elf, obj->efile.strtabidx,
3276				  sym.st_name) ? : "<?>";
3277
3278		pr_debug("relo for shdr %u, symb %zu, value %zu, type %d, bind %d, name %d (\'%s\'), insn %u\n",
3279			 (__u32)sym.st_shndx, (size_t)GELF_R_SYM(rel.r_info),
3280			 (size_t)sym.st_value, GELF_ST_TYPE(sym.st_info),
3281			 GELF_ST_BIND(sym.st_info), sym.st_name, name,
3282			 insn_idx);
3283
3284		err = bpf_program__record_reloc(prog, &prog->reloc_desc[i],
3285						insn_idx, name, &sym, &rel);
3286		if (err)
3287			return err;
3288	}
3289	return 0;
3290}
3291
3292static int bpf_map_find_btf_info(struct bpf_object *obj, struct bpf_map *map)
3293{
3294	struct bpf_map_def *def = &map->def;
3295	__u32 key_type_id = 0, value_type_id = 0;
3296	int ret;
3297
3298	/* if it's BTF-defined map, we don't need to search for type IDs.
3299	 * For struct_ops map, it does not need btf_key_type_id and
3300	 * btf_value_type_id.
3301	 */
3302	if (map->sec_idx == obj->efile.btf_maps_shndx ||
3303	    bpf_map__is_struct_ops(map))
3304		return 0;
3305
3306	if (!bpf_map__is_internal(map)) {
3307		ret = btf__get_map_kv_tids(obj->btf, map->name, def->key_size,
3308					   def->value_size, &key_type_id,
3309					   &value_type_id);
3310	} else {
3311		/*
3312		 * LLVM annotates global data differently in BTF, that is,
3313		 * only as '.data', '.bss' or '.rodata'.
3314		 */
3315		ret = btf__find_by_name(obj->btf,
3316				libbpf_type_to_btf_name[map->libbpf_type]);
3317	}
3318	if (ret < 0)
3319		return ret;
3320
3321	map->btf_key_type_id = key_type_id;
3322	map->btf_value_type_id = bpf_map__is_internal(map) ?
3323				 ret : value_type_id;
3324	return 0;
3325}
3326
3327int bpf_map__reuse_fd(struct bpf_map *map, int fd)
3328{
3329	struct bpf_map_info info = {};
3330	__u32 len = sizeof(info);
3331	int new_fd, err;
3332	char *new_name;
3333
3334	err = bpf_obj_get_info_by_fd(fd, &info, &len);
3335	if (err)
3336		return err;
3337
3338	new_name = strdup(info.name);
3339	if (!new_name)
3340		return -errno;
3341
3342	new_fd = open("/", O_RDONLY | O_CLOEXEC);
3343	if (new_fd < 0) {
3344		err = -errno;
3345		goto err_free_new_name;
3346	}
3347
3348	new_fd = dup3(fd, new_fd, O_CLOEXEC);
3349	if (new_fd < 0) {
3350		err = -errno;
3351		goto err_close_new_fd;
3352	}
3353
3354	err = zclose(map->fd);
3355	if (err) {
3356		err = -errno;
3357		goto err_close_new_fd;
3358	}
3359	free(map->name);
3360
3361	map->fd = new_fd;
3362	map->name = new_name;
3363	map->def.type = info.type;
3364	map->def.key_size = info.key_size;
3365	map->def.value_size = info.value_size;
3366	map->def.max_entries = info.max_entries;
3367	map->def.map_flags = info.map_flags;
3368	map->btf_key_type_id = info.btf_key_type_id;
3369	map->btf_value_type_id = info.btf_value_type_id;
3370	map->reused = true;
3371
3372	return 0;
3373
3374err_close_new_fd:
3375	close(new_fd);
3376err_free_new_name:
3377	free(new_name);
3378	return err;
3379}
3380
3381__u32 bpf_map__max_entries(const struct bpf_map *map)
3382{
3383	return map->def.max_entries;
3384}
3385
3386int bpf_map__set_max_entries(struct bpf_map *map, __u32 max_entries)
3387{
3388	if (map->fd >= 0)
3389		return -EBUSY;
3390	map->def.max_entries = max_entries;
3391	return 0;
3392}
3393
3394int bpf_map__resize(struct bpf_map *map, __u32 max_entries)
3395{
3396	if (!map || !max_entries)
3397		return -EINVAL;
3398
3399	return bpf_map__set_max_entries(map, max_entries);
3400}
3401
3402static int
3403bpf_object__probe_loading(struct bpf_object *obj)
3404{
3405	struct bpf_load_program_attr attr;
3406	char *cp, errmsg[STRERR_BUFSIZE];
3407	struct bpf_insn insns[] = {
3408		BPF_MOV64_IMM(BPF_REG_0, 0),
3409		BPF_EXIT_INSN(),
3410	};
3411	int ret;
3412
3413	/* make sure basic loading works */
3414
3415	memset(&attr, 0, sizeof(attr));
3416	attr.prog_type = BPF_PROG_TYPE_SOCKET_FILTER;
3417	attr.insns = insns;
3418	attr.insns_cnt = ARRAY_SIZE(insns);
3419	attr.license = "GPL";
3420
3421	ret = bpf_load_program_xattr(&attr, NULL, 0);
3422	if (ret < 0) {
3423		ret = errno;
3424		cp = libbpf_strerror_r(ret, errmsg, sizeof(errmsg));
3425		pr_warn("Error in %s():%s(%d). Couldn't load trivial BPF "
3426			"program. Make sure your kernel supports BPF "
3427			"(CONFIG_BPF_SYSCALL=y) and/or that RLIMIT_MEMLOCK is "
3428			"set to big enough value.\n", __func__, cp, ret);
3429		return -ret;
3430	}
3431	close(ret);
3432
3433	return 0;
3434}
3435
3436static int
3437bpf_object__probe_name(struct bpf_object *obj)
3438{
3439	struct bpf_load_program_attr attr;
3440	struct bpf_insn insns[] = {
3441		BPF_MOV64_IMM(BPF_REG_0, 0),
3442		BPF_EXIT_INSN(),
3443	};
3444	int ret;
3445
3446	/* make sure loading with name works */
3447
3448	memset(&attr, 0, sizeof(attr));
3449	attr.prog_type = BPF_PROG_TYPE_SOCKET_FILTER;
3450	attr.insns = insns;
3451	attr.insns_cnt = ARRAY_SIZE(insns);
3452	attr.license = "GPL";
3453	attr.name = "test";
3454	ret = bpf_load_program_xattr(&attr, NULL, 0);
3455	if (ret >= 0) {
3456		obj->caps.name = 1;
3457		close(ret);
3458	}
3459
3460	return 0;
3461}
3462
3463static int
3464bpf_object__probe_global_data(struct bpf_object *obj)
3465{
3466	struct bpf_load_program_attr prg_attr;
3467	struct bpf_create_map_attr map_attr;
3468	char *cp, errmsg[STRERR_BUFSIZE];
3469	struct bpf_insn insns[] = {
3470		BPF_LD_MAP_VALUE(BPF_REG_1, 0, 16),
3471		BPF_ST_MEM(BPF_DW, BPF_REG_1, 0, 42),
3472		BPF_MOV64_IMM(BPF_REG_0, 0),
3473		BPF_EXIT_INSN(),
3474	};
3475	int ret, map;
3476
3477	memset(&map_attr, 0, sizeof(map_attr));
3478	map_attr.map_type = BPF_MAP_TYPE_ARRAY;
3479	map_attr.key_size = sizeof(int);
3480	map_attr.value_size = 32;
3481	map_attr.max_entries = 1;
3482
3483	map = bpf_create_map_xattr(&map_attr);
3484	if (map < 0) {
3485		ret = -errno;
3486		cp = libbpf_strerror_r(ret, errmsg, sizeof(errmsg));
3487		pr_warn("Error in %s():%s(%d). Couldn't create simple array map.\n",
3488			__func__, cp, -ret);
3489		return ret;
3490	}
3491
3492	insns[0].imm = map;
3493
3494	memset(&prg_attr, 0, sizeof(prg_attr));
3495	prg_attr.prog_type = BPF_PROG_TYPE_SOCKET_FILTER;
3496	prg_attr.insns = insns;
3497	prg_attr.insns_cnt = ARRAY_SIZE(insns);
3498	prg_attr.license = "GPL";
3499
3500	ret = bpf_load_program_xattr(&prg_attr, NULL, 0);
3501	if (ret >= 0) {
3502		obj->caps.global_data = 1;
3503		close(ret);
3504	}
3505
3506	close(map);
3507	return 0;
3508}
3509
3510static int bpf_object__probe_btf_func(struct bpf_object *obj)
3511{
3512	static const char strs[] = "\0int\0x\0a";
3513	/* void x(int a) {} */
3514	__u32 types[] = {
3515		/* int */
3516		BTF_TYPE_INT_ENC(1, BTF_INT_SIGNED, 0, 32, 4),  /* [1] */
3517		/* FUNC_PROTO */                                /* [2] */
3518		BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_FUNC_PROTO, 0, 1), 0),
3519		BTF_PARAM_ENC(7, 1),
3520		/* FUNC x */                                    /* [3] */
3521		BTF_TYPE_ENC(5, BTF_INFO_ENC(BTF_KIND_FUNC, 0, 0), 2),
3522	};
3523	int btf_fd;
3524
3525	btf_fd = libbpf__load_raw_btf((char *)types, sizeof(types),
3526				      strs, sizeof(strs));
3527	if (btf_fd >= 0) {
3528		obj->caps.btf_func = 1;
3529		close(btf_fd);
3530		return 1;
3531	}
3532
3533	return 0;
3534}
3535
3536static int bpf_object__probe_btf_func_global(struct bpf_object *obj)
3537{
3538	static const char strs[] = "\0int\0x\0a";
3539	/* static void x(int a) {} */
3540	__u32 types[] = {
3541		/* int */
3542		BTF_TYPE_INT_ENC(1, BTF_INT_SIGNED, 0, 32, 4),  /* [1] */
3543		/* FUNC_PROTO */                                /* [2] */
3544		BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_FUNC_PROTO, 0, 1), 0),
3545		BTF_PARAM_ENC(7, 1),
3546		/* FUNC x BTF_FUNC_GLOBAL */                    /* [3] */
3547		BTF_TYPE_ENC(5, BTF_INFO_ENC(BTF_KIND_FUNC, 0, BTF_FUNC_GLOBAL), 2),
3548	};
3549	int btf_fd;
3550
3551	btf_fd = libbpf__load_raw_btf((char *)types, sizeof(types),
3552				      strs, sizeof(strs));
3553	if (btf_fd >= 0) {
3554		obj->caps.btf_func_global = 1;
3555		close(btf_fd);
3556		return 1;
3557	}
3558
3559	return 0;
3560}
3561
3562static int bpf_object__probe_btf_datasec(struct bpf_object *obj)
3563{
3564	static const char strs[] = "\0x\0.data";
3565	/* static int a; */
3566	__u32 types[] = {
3567		/* int */
3568		BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4),  /* [1] */
3569		/* VAR x */                                     /* [2] */
3570		BTF_TYPE_ENC(1, BTF_INFO_ENC(BTF_KIND_VAR, 0, 0), 1),
3571		BTF_VAR_STATIC,
3572		/* DATASEC val */                               /* [3] */
3573		BTF_TYPE_ENC(3, BTF_INFO_ENC(BTF_KIND_DATASEC, 0, 1), 4),
3574		BTF_VAR_SECINFO_ENC(2, 0, 4),
3575	};
3576	int btf_fd;
3577
3578	btf_fd = libbpf__load_raw_btf((char *)types, sizeof(types),
3579				      strs, sizeof(strs));
3580	if (btf_fd >= 0) {
3581		obj->caps.btf_datasec = 1;
3582		close(btf_fd);
3583		return 1;
3584	}
3585
3586	return 0;
3587}
3588
3589static int bpf_object__probe_array_mmap(struct bpf_object *obj)
3590{
3591	struct bpf_create_map_attr attr = {
3592		.map_type = BPF_MAP_TYPE_ARRAY,
3593		.map_flags = BPF_F_MMAPABLE,
3594		.key_size = sizeof(int),
3595		.value_size = sizeof(int),
3596		.max_entries = 1,
3597	};
3598	int fd;
3599
3600	fd = bpf_create_map_xattr(&attr);
3601	if (fd >= 0) {
3602		obj->caps.array_mmap = 1;
3603		close(fd);
3604		return 1;
3605	}
3606
3607	return 0;
3608}
3609
3610static int
3611bpf_object__probe_exp_attach_type(struct bpf_object *obj)
3612{
3613	struct bpf_load_program_attr attr;
3614	struct bpf_insn insns[] = {
3615		BPF_MOV64_IMM(BPF_REG_0, 0),
3616		BPF_EXIT_INSN(),
3617	};
3618	int fd;
3619
3620	memset(&attr, 0, sizeof(attr));
3621	/* use any valid combination of program type and (optional)
3622	 * non-zero expected attach type (i.e., not a BPF_CGROUP_INET_INGRESS)
3623	 * to see if kernel supports expected_attach_type field for
3624	 * BPF_PROG_LOAD command
3625	 */
3626	attr.prog_type = BPF_PROG_TYPE_CGROUP_SOCK;
3627	attr.expected_attach_type = BPF_CGROUP_INET_SOCK_CREATE;
3628	attr.insns = insns;
3629	attr.insns_cnt = ARRAY_SIZE(insns);
3630	attr.license = "GPL";
3631
3632	fd = bpf_load_program_xattr(&attr, NULL, 0);
3633	if (fd >= 0) {
3634		obj->caps.exp_attach_type = 1;
3635		close(fd);
3636		return 1;
3637	}
3638	return 0;
3639}
3640
3641static int
3642bpf_object__probe_caps(struct bpf_object *obj)
3643{
3644	int (*probe_fn[])(struct bpf_object *obj) = {
3645		bpf_object__probe_name,
3646		bpf_object__probe_global_data,
3647		bpf_object__probe_btf_func,
3648		bpf_object__probe_btf_func_global,
3649		bpf_object__probe_btf_datasec,
3650		bpf_object__probe_array_mmap,
3651		bpf_object__probe_exp_attach_type,
3652	};
3653	int i, ret;
3654
3655	for (i = 0; i < ARRAY_SIZE(probe_fn); i++) {
3656		ret = probe_fn[i](obj);
3657		if (ret < 0)
3658			pr_debug("Probe #%d failed with %d.\n", i, ret);
3659	}
3660
3661	return 0;
3662}
3663
3664static bool map_is_reuse_compat(const struct bpf_map *map, int map_fd)
3665{
3666	struct bpf_map_info map_info = {};
3667	char msg[STRERR_BUFSIZE];
3668	__u32 map_info_len;
3669
3670	map_info_len = sizeof(map_info);
3671
3672	if (bpf_obj_get_info_by_fd(map_fd, &map_info, &map_info_len)) {
3673		pr_warn("failed to get map info for map FD %d: %s\n",
3674			map_fd, libbpf_strerror_r(errno, msg, sizeof(msg)));
3675		return false;
3676	}
3677
3678	return (map_info.type == map->def.type &&
3679		map_info.key_size == map->def.key_size &&
3680		map_info.value_size == map->def.value_size &&
3681		map_info.max_entries == map->def.max_entries &&
3682		map_info.map_flags == map->def.map_flags);
3683}
3684
3685static int
3686bpf_object__reuse_map(struct bpf_map *map)
3687{
3688	char *cp, errmsg[STRERR_BUFSIZE];
3689	int err, pin_fd;
3690
3691	pin_fd = bpf_obj_get(map->pin_path);
3692	if (pin_fd < 0) {
3693		err = -errno;
3694		if (err == -ENOENT) {
3695			pr_debug("found no pinned map to reuse at '%s'\n",
3696				 map->pin_path);
3697			return 0;
3698		}
3699
3700		cp = libbpf_strerror_r(-err, errmsg, sizeof(errmsg));
3701		pr_warn("couldn't retrieve pinned map '%s': %s\n",
3702			map->pin_path, cp);
3703		return err;
3704	}
3705
3706	if (!map_is_reuse_compat(map, pin_fd)) {
3707		pr_warn("couldn't reuse pinned map at '%s': parameter mismatch\n",
3708			map->pin_path);
3709		close(pin_fd);
3710		return -EINVAL;
3711	}
3712
3713	err = bpf_map__reuse_fd(map, pin_fd);
3714	if (err) {
3715		close(pin_fd);
3716		return err;
3717	}
3718	map->pinned = true;
3719	pr_debug("reused pinned map at '%s'\n", map->pin_path);
3720
3721	return 0;
3722}
3723
3724static int
3725bpf_object__populate_internal_map(struct bpf_object *obj, struct bpf_map *map)
3726{
3727	enum libbpf_map_type map_type = map->libbpf_type;
3728	char *cp, errmsg[STRERR_BUFSIZE];
3729	int err, zero = 0;
3730
3731	err = bpf_map_update_elem(map->fd, &zero, map->mmaped, 0);
3732	if (err) {
3733		err = -errno;
3734		cp = libbpf_strerror_r(err, errmsg, sizeof(errmsg));
3735		pr_warn("Error setting initial map(%s) contents: %s\n",
3736			map->name, cp);
3737		return err;
3738	}
3739
3740	/* Freeze .rodata and .kconfig map as read-only from syscall side. */
3741	if (map_type == LIBBPF_MAP_RODATA || map_type == LIBBPF_MAP_KCONFIG) {
3742		err = bpf_map_freeze(map->fd);
3743		if (err) {
3744			err = -errno;
3745			cp = libbpf_strerror_r(err, errmsg, sizeof(errmsg));
3746			pr_warn("Error freezing map(%s) as read-only: %s\n",
3747				map->name, cp);
3748			return err;
3749		}
3750	}
3751	return 0;
3752}
3753
3754static void bpf_map__destroy(struct bpf_map *map);
3755
3756static int bpf_object__create_map(struct bpf_object *obj, struct bpf_map *map)
3757{
3758	struct bpf_create_map_attr create_attr;
3759	struct bpf_map_def *def = &map->def;
3760
3761	memset(&create_attr, 0, sizeof(create_attr));
3762
3763	if (obj->caps.name)
3764		create_attr.name = map->name;
3765	create_attr.map_ifindex = map->map_ifindex;
3766	create_attr.map_type = def->type;
3767	create_attr.map_flags = def->map_flags;
3768	create_attr.key_size = def->key_size;
3769	create_attr.value_size = def->value_size;
3770	create_attr.numa_node = map->numa_node;
3771
3772	if (def->type == BPF_MAP_TYPE_PERF_EVENT_ARRAY && !def->max_entries) {
3773		int nr_cpus;
3774
3775		nr_cpus = libbpf_num_possible_cpus();
3776		if (nr_cpus < 0) {
3777			pr_warn("map '%s': failed to determine number of system CPUs: %d\n",
3778				map->name, nr_cpus);
3779			return nr_cpus;
3780		}
3781		pr_debug("map '%s': setting size to %d\n", map->name, nr_cpus);
3782		create_attr.max_entries = nr_cpus;
3783	} else {
3784		create_attr.max_entries = def->max_entries;
3785	}
3786
3787	if (bpf_map__is_struct_ops(map))
3788		create_attr.btf_vmlinux_value_type_id =
3789			map->btf_vmlinux_value_type_id;
3790
3791	create_attr.btf_fd = 0;
3792	create_attr.btf_key_type_id = 0;
3793	create_attr.btf_value_type_id = 0;
3794	if (obj->btf && btf__fd(obj->btf) >= 0 && !bpf_map_find_btf_info(obj, map)) {
3795		create_attr.btf_fd = btf__fd(obj->btf);
3796		create_attr.btf_key_type_id = map->btf_key_type_id;
3797		create_attr.btf_value_type_id = map->btf_value_type_id;
3798	}
3799
3800	if (bpf_map_type__is_map_in_map(def->type)) {
3801		if (map->inner_map) {
3802			int err;
3803
3804			err = bpf_object__create_map(obj, map->inner_map);
3805			if (err) {
3806				pr_warn("map '%s': failed to create inner map: %d\n",
3807					map->name, err);
3808				return err;
3809			}
3810			map->inner_map_fd = bpf_map__fd(map->inner_map);
3811		}
3812		if (map->inner_map_fd >= 0)
3813			create_attr.inner_map_fd = map->inner_map_fd;
3814	}
3815
3816	map->fd = bpf_create_map_xattr(&create_attr);
3817	if (map->fd < 0 && (create_attr.btf_key_type_id ||
3818			    create_attr.btf_value_type_id)) {
3819		char *cp, errmsg[STRERR_BUFSIZE];
3820		int err = -errno;
3821
3822		cp = libbpf_strerror_r(err, errmsg, sizeof(errmsg));
3823		pr_warn("Error in bpf_create_map_xattr(%s):%s(%d). Retrying without BTF.\n",
3824			map->name, cp, err);
3825		create_attr.btf_fd = 0;
3826		create_attr.btf_key_type_id = 0;
3827		create_attr.btf_value_type_id = 0;
3828		map->btf_key_type_id = 0;
3829		map->btf_value_type_id = 0;
3830		map->fd = bpf_create_map_xattr(&create_attr);
3831	}
3832
3833	if (map->fd < 0)
3834		return -errno;
3835
3836	if (bpf_map_type__is_map_in_map(def->type) && map->inner_map) {
3837		bpf_map__destroy(map->inner_map);
3838		zfree(&map->inner_map);
3839	}
3840
3841	return 0;
3842}
3843
3844static int
3845bpf_object__create_maps(struct bpf_object *obj)
3846{
3847	struct bpf_map *map;
3848	char *cp, errmsg[STRERR_BUFSIZE];
3849	unsigned int i, j;
3850	int err;
3851
3852	for (i = 0; i < obj->nr_maps; i++) {
3853		map = &obj->maps[i];
3854
3855		if (map->pin_path) {
3856			err = bpf_object__reuse_map(map);
3857			if (err) {
3858				pr_warn("map '%s': error reusing pinned map\n",
3859					map->name);
3860				goto err_out;
3861			}
3862		}
3863
3864		if (map->fd >= 0) {
3865			pr_debug("map '%s': skipping creation (preset fd=%d)\n",
3866				 map->name, map->fd);
3867			continue;
3868		}
3869
3870		err = bpf_object__create_map(obj, map);
3871		if (err)
3872			goto err_out;
3873
3874		pr_debug("map '%s': created successfully, fd=%d\n", map->name,
3875			 map->fd);
3876
3877		if (bpf_map__is_internal(map)) {
3878			err = bpf_object__populate_internal_map(obj, map);
3879			if (err < 0) {
3880				zclose(map->fd);
3881				goto err_out;
3882			}
3883		}
3884
3885		if (map->init_slots_sz) {
3886			for (j = 0; j < map->init_slots_sz; j++) {
3887				const struct bpf_map *targ_map;
3888				int fd;
3889
3890				if (!map->init_slots[j])
3891					continue;
3892
3893				targ_map = map->init_slots[j];
3894				fd = bpf_map__fd(targ_map);
3895				err = bpf_map_update_elem(map->fd, &j, &fd, 0);
3896				if (err) {
3897					err = -errno;
3898					pr_warn("map '%s': failed to initialize slot [%d] to map '%s' fd=%d: %d\n",
3899						map->name, j, targ_map->name,
3900						fd, err);
3901					goto err_out;
3902				}
3903				pr_debug("map '%s': slot [%d] set to map '%s' fd=%d\n",
3904					 map->name, j, targ_map->name, fd);
3905			}
3906			zfree(&map->init_slots);
3907			map->init_slots_sz = 0;
3908		}
3909
3910		if (map->pin_path && !map->pinned) {
3911			err = bpf_map__pin(map, NULL);
3912			if (err) {
3913				pr_warn("map '%s': failed to auto-pin at '%s': %d\n",
3914					map->name, map->pin_path, err);
3915				zclose(map->fd);
3916				goto err_out;
3917			}
3918		}
3919	}
3920
3921	return 0;
3922
3923err_out:
3924	cp = libbpf_strerror_r(err, errmsg, sizeof(errmsg));
3925	pr_warn("map '%s': failed to create: %s(%d)\n", map->name, cp, err);
3926	pr_perm_msg(err);
3927	for (j = 0; j < i; j++)
3928		zclose(obj->maps[j].fd);
3929	return err;
3930}
3931
3932static int
3933check_btf_ext_reloc_err(struct bpf_program *prog, int err,
3934			void *btf_prog_info, const char *info_name)
3935{
3936	if (err != -ENOENT) {
3937		pr_warn("Error in loading %s for sec %s.\n",
3938			info_name, prog->section_name);
3939		return err;
3940	}
3941
3942	/* err == -ENOENT (i.e. prog->section_name not found in btf_ext) */
3943
3944	if (btf_prog_info) {
3945		/*
3946		 * Some info has already been found but has problem
3947		 * in the last btf_ext reloc. Must have to error out.
3948		 */
3949		pr_warn("Error in relocating %s for sec %s.\n",
3950			info_name, prog->section_name);
3951		return err;
3952	}
3953
3954	/* Have problem loading the very first info. Ignore the rest. */
3955	pr_warn("Cannot find %s for main program sec %s. Ignore all %s.\n",
3956		info_name, prog->section_name, info_name);
3957	return 0;
3958}
3959
3960static int
3961bpf_program_reloc_btf_ext(struct bpf_program *prog, struct bpf_object *obj,
3962			  const char *section_name,  __u32 insn_offset)
3963{
3964	int err;
3965
3966	if (!insn_offset || prog->func_info) {
3967		/*
3968		 * !insn_offset => main program
3969		 *
3970		 * For sub prog, the main program's func_info has to
3971		 * be loaded first (i.e. prog->func_info != NULL)
3972		 */
3973		err = btf_ext__reloc_func_info(obj->btf, obj->btf_ext,
3974					       section_name, insn_offset,
3975					       &prog->func_info,
3976					       &prog->func_info_cnt);
3977		if (err)
3978			return check_btf_ext_reloc_err(prog, err,
3979						       prog->func_info,
3980						       "bpf_func_info");
3981
3982		prog->func_info_rec_size = btf_ext__func_info_rec_size(obj->btf_ext);
3983	}
3984
3985	if (!insn_offset || prog->line_info) {
3986		err = btf_ext__reloc_line_info(obj->btf, obj->btf_ext,
3987					       section_name, insn_offset,
3988					       &prog->line_info,
3989					       &prog->line_info_cnt);
3990		if (err)
3991			return check_btf_ext_reloc_err(prog, err,
3992						       prog->line_info,
3993						       "bpf_line_info");
3994
3995		prog->line_info_rec_size = btf_ext__line_info_rec_size(obj->btf_ext);
3996	}
3997
3998	return 0;
3999}
4000
4001#define BPF_CORE_SPEC_MAX_LEN 64
4002
4003/* represents BPF CO-RE field or array element accessor */
4004struct bpf_core_accessor {
4005	__u32 type_id;		/* struct/union type or array element type */
4006	__u32 idx;		/* field index or array index */
4007	const char *name;	/* field name or NULL for array accessor */
4008};
4009
4010struct bpf_core_spec {
4011	const struct btf *btf;
4012	/* high-level spec: named fields and array indices only */
4013	struct bpf_core_accessor spec[BPF_CORE_SPEC_MAX_LEN];
4014	/* high-level spec length */
4015	int len;
4016	/* raw, low-level spec: 1-to-1 with accessor spec string */
4017	int raw_spec[BPF_CORE_SPEC_MAX_LEN];
4018	/* raw spec length */
4019	int raw_len;
4020	/* field bit offset represented by spec */
4021	__u32 bit_offset;
4022};
4023
4024static bool str_is_empty(const char *s)
4025{
4026	return !s || !s[0];
4027}
4028
4029static bool is_flex_arr(const struct btf *btf,
4030			const struct bpf_core_accessor *acc,
4031			const struct btf_array *arr)
4032{
4033	const struct btf_type *t;
4034
4035	/* not a flexible array, if not inside a struct or has non-zero size */
4036	if (!acc->name || arr->nelems > 0)
4037		return false;
4038
4039	/* has to be the last member of enclosing struct */
4040	t = btf__type_by_id(btf, acc->type_id);
4041	return acc->idx == btf_vlen(t) - 1;
4042}
4043
4044/*
4045 * Turn bpf_field_reloc into a low- and high-level spec representation,
4046 * validating correctness along the way, as well as calculating resulting
4047 * field bit offset, specified by accessor string. Low-level spec captures
4048 * every single level of nestedness, including traversing anonymous
4049 * struct/union members. High-level one only captures semantically meaningful
4050 * "turning points": named fields and array indicies.
4051 * E.g., for this case:
4052 *
4053 *   struct sample {
4054 *       int __unimportant;
4055 *       struct {
4056 *           int __1;
4057 *           int __2;
4058 *           int a[7];
4059 *       };
4060 *   };
4061 *
4062 *   struct sample *s = ...;
4063 *
4064 *   int x = &s->a[3]; // access string = '0:1:2:3'
4065 *
4066 * Low-level spec has 1:1 mapping with each element of access string (it's
4067 * just a parsed access string representation): [0, 1, 2, 3].
4068 *
4069 * High-level spec will capture only 3 points:
4070 *   - intial zero-index access by pointer (&s->... is the same as &s[0]...);
4071 *   - field 'a' access (corresponds to '2' in low-level spec);
4072 *   - array element #3 access (corresponds to '3' in low-level spec).
4073 *
4074 */
4075static int bpf_core_spec_parse(const struct btf *btf,
4076			       __u32 type_id,
4077			       const char *spec_str,
4078			       struct bpf_core_spec *spec)
4079{
4080	int access_idx, parsed_len, i;
4081	struct bpf_core_accessor *acc;
4082	const struct btf_type *t;
4083	const char *name;
4084	__u32 id;
4085	__s64 sz;
4086
4087	if (str_is_empty(spec_str) || *spec_str == ':')
4088		return -EINVAL;
4089
4090	memset(spec, 0, sizeof(*spec));
4091	spec->btf = btf;
4092
4093	/* parse spec_str="0:1:2:3:4" into array raw_spec=[0, 1, 2, 3, 4] */
4094	while (*spec_str) {
4095		if (*spec_str == ':')
4096			++spec_str;
4097		if (sscanf(spec_str, "%d%n", &access_idx, &parsed_len) != 1)
4098			return -EINVAL;
4099		if (spec->raw_len == BPF_CORE_SPEC_MAX_LEN)
4100			return -E2BIG;
4101		spec_str += parsed_len;
4102		spec->raw_spec[spec->raw_len++] = access_idx;
4103	}
4104
4105	if (spec->raw_len == 0)
4106		return -EINVAL;
4107
4108	/* first spec value is always reloc type array index */
4109	t = skip_mods_and_typedefs(btf, type_id, &id);
4110	if (!t)
4111		return -EINVAL;
4112
4113	access_idx = spec->raw_spec[0];
4114	spec->spec[0].type_id = id;
4115	spec->spec[0].idx = access_idx;
4116	spec->len++;
4117
4118	sz = btf__resolve_size(btf, id);
4119	if (sz < 0)
4120		return sz;
4121	spec->bit_offset = access_idx * sz * 8;
4122
4123	for (i = 1; i < spec->raw_len; i++) {
4124		t = skip_mods_and_typedefs(btf, id, &id);
4125		if (!t)
4126			return -EINVAL;
4127
4128		access_idx = spec->raw_spec[i];
4129		acc = &spec->spec[spec->len];
4130
4131		if (btf_is_composite(t)) {
4132			const struct btf_member *m;
4133			__u32 bit_offset;
4134
4135			if (access_idx >= btf_vlen(t))
4136				return -EINVAL;
4137
4138			bit_offset = btf_member_bit_offset(t, access_idx);
4139			spec->bit_offset += bit_offset;
4140
4141			m = btf_members(t) + access_idx;
4142			if (m->name_off) {
4143				name = btf__name_by_offset(btf, m->name_off);
4144				if (str_is_empty(name))
4145					return -EINVAL;
4146
4147				acc->type_id = id;
4148				acc->idx = access_idx;
4149				acc->name = name;
4150				spec->len++;
4151			}
4152
4153			id = m->type;
4154		} else if (btf_is_array(t)) {
4155			const struct btf_array *a = btf_array(t);
4156			bool flex;
4157
4158			t = skip_mods_and_typedefs(btf, a->type, &id);
4159			if (!t)
4160				return -EINVAL;
4161
4162			flex = is_flex_arr(btf, acc - 1, a);
4163			if (!flex && access_idx >= a->nelems)
4164				return -EINVAL;
4165
4166			spec->spec[spec->len].type_id = id;
4167			spec->spec[spec->len].idx = access_idx;
4168			spec->len++;
4169
4170			sz = btf__resolve_size(btf, id);
4171			if (sz < 0)
4172				return sz;
4173			spec->bit_offset += access_idx * sz * 8;
4174		} else {
4175			pr_warn("relo for [%u] %s (at idx %d) captures type [%d] of unexpected kind %d\n",
4176				type_id, spec_str, i, id, btf_kind(t));
4177			return -EINVAL;
4178		}
4179	}
4180
4181	return 0;
4182}
4183
4184static bool bpf_core_is_flavor_sep(const char *s)
4185{
4186	/* check X___Y name pattern, where X and Y are not underscores */
4187	return s[0] != '_' &&				      /* X */
4188	       s[1] == '_' && s[2] == '_' && s[3] == '_' &&   /* ___ */
4189	       s[4] != '_';				      /* Y */
4190}
4191
4192/* Given 'some_struct_name___with_flavor' return the length of a name prefix
4193 * before last triple underscore. Struct name part after last triple
4194 * underscore is ignored by BPF CO-RE relocation during relocation matching.
4195 */
4196static size_t bpf_core_essential_name_len(const char *name)
4197{
4198	size_t n = strlen(name);
4199	int i;
4200
4201	for (i = n - 5; i >= 0; i--) {
4202		if (bpf_core_is_flavor_sep(name + i))
4203			return i + 1;
4204	}
4205	return n;
4206}
4207
4208/* dynamically sized list of type IDs */
4209struct ids_vec {
4210	__u32 *data;
4211	int len;
4212};
4213
4214static void bpf_core_free_cands(struct ids_vec *cand_ids)
4215{
4216	free(cand_ids->data);
4217	free(cand_ids);
4218}
4219
4220static struct ids_vec *bpf_core_find_cands(const struct btf *local_btf,
4221					   __u32 local_type_id,
4222					   const struct btf *targ_btf)
4223{
4224	size_t local_essent_len, targ_essent_len;
4225	const char *local_name, *targ_name;
4226	const struct btf_type *t;
4227	struct ids_vec *cand_ids;
4228	__u32 *new_ids;
4229	int i, err, n;
4230
4231	t = btf__type_by_id(local_btf, local_type_id);
4232	if (!t)
4233		return ERR_PTR(-EINVAL);
4234
4235	local_name = btf__name_by_offset(local_btf, t->name_off);
4236	if (str_is_empty(local_name))
4237		return ERR_PTR(-EINVAL);
4238	local_essent_len = bpf_core_essential_name_len(local_name);
4239
4240	cand_ids = calloc(1, sizeof(*cand_ids));
4241	if (!cand_ids)
4242		return ERR_PTR(-ENOMEM);
4243
4244	n = btf__get_nr_types(targ_btf);
4245	for (i = 1; i <= n; i++) {
4246		t = btf__type_by_id(targ_btf, i);
4247		targ_name = btf__name_by_offset(targ_btf, t->name_off);
4248		if (str_is_empty(targ_name))
4249			continue;
4250
4251		t = skip_mods_and_typedefs(targ_btf, i, NULL);
4252		if (!btf_is_composite(t) && !btf_is_array(t))
4253			continue;
4254
4255		targ_essent_len = bpf_core_essential_name_len(targ_name);
4256		if (targ_essent_len != local_essent_len)
4257			continue;
4258
4259		if (strncmp(local_name, targ_name, local_essent_len) == 0) {
4260			pr_debug("[%d] %s: found candidate [%d] %s\n",
4261				 local_type_id, local_name, i, targ_name);
4262			new_ids = reallocarray(cand_ids->data,
4263					       cand_ids->len + 1,
4264					       sizeof(*cand_ids->data));
4265			if (!new_ids) {
4266				err = -ENOMEM;
4267				goto err_out;
4268			}
4269			cand_ids->data = new_ids;
4270			cand_ids->data[cand_ids->len++] = i;
4271		}
4272	}
4273	return cand_ids;
4274err_out:
4275	bpf_core_free_cands(cand_ids);
4276	return ERR_PTR(err);
4277}
4278
4279/* Check two types for compatibility, skipping const/volatile/restrict and
4280 * typedefs, to ensure we are relocating compatible entities:
4281 *   - any two STRUCTs/UNIONs are compatible and can be mixed;
4282 *   - any two FWDs are compatible, if their names match (modulo flavor suffix);
4283 *   - any two PTRs are always compatible;
4284 *   - for ENUMs, names should be the same (ignoring flavor suffix) or at
4285 *     least one of enums should be anonymous;
4286 *   - for ENUMs, check sizes, names are ignored;
4287 *   - for INT, size and signedness are ignored;
4288 *   - for ARRAY, dimensionality is ignored, element types are checked for
4289 *     compatibility recursively;
4290 *   - everything else shouldn't be ever a target of relocation.
4291 * These rules are not set in stone and probably will be adjusted as we get
4292 * more experience with using BPF CO-RE relocations.
4293 */
4294static int bpf_core_fields_are_compat(const struct btf *local_btf,
4295				      __u32 local_id,
4296				      const struct btf *targ_btf,
4297				      __u32 targ_id)
4298{
4299	const struct btf_type *local_type, *targ_type;
4300
4301recur:
4302	local_type = skip_mods_and_typedefs(local_btf, local_id, &local_id);
4303	targ_type = skip_mods_and_typedefs(targ_btf, targ_id, &targ_id);
4304	if (!local_type || !targ_type)
4305		return -EINVAL;
4306
4307	if (btf_is_composite(local_type) && btf_is_composite(targ_type))
4308		return 1;
4309	if (btf_kind(local_type) != btf_kind(targ_type))
4310		return 0;
4311
4312	switch (btf_kind(local_type)) {
4313	case BTF_KIND_PTR:
4314		return 1;
4315	case BTF_KIND_FWD:
4316	case BTF_KIND_ENUM: {
4317		const char *local_name, *targ_name;
4318		size_t local_len, targ_len;
4319
4320		local_name = btf__name_by_offset(local_btf,
4321						 local_type->name_off);
4322		targ_name = btf__name_by_offset(targ_btf, targ_type->name_off);
4323		local_len = bpf_core_essential_name_len(local_name);
4324		targ_len = bpf_core_essential_name_len(targ_name);
4325		/* one of them is anonymous or both w/ same flavor-less names */
4326		return local_len == 0 || targ_len == 0 ||
4327		       (local_len == targ_len &&
4328			strncmp(local_name, targ_name, local_len) == 0);
4329	}
4330	case BTF_KIND_INT:
4331		/* just reject deprecated bitfield-like integers; all other
4332		 * integers are by default compatible between each other
4333		 */
4334		return btf_int_offset(local_type) == 0 &&
4335		       btf_int_offset(targ_type) == 0;
4336	case BTF_KIND_ARRAY:
4337		local_id = btf_array(local_type)->type;
4338		targ_id = btf_array(targ_type)->type;
4339		goto recur;
4340	default:
4341		pr_warn("unexpected kind %d relocated, local [%d], target [%d]\n",
4342			btf_kind(local_type), local_id, targ_id);
4343		return 0;
4344	}
4345}
4346
4347/*
4348 * Given single high-level named field accessor in local type, find
4349 * corresponding high-level accessor for a target type. Along the way,
4350 * maintain low-level spec for target as well. Also keep updating target
4351 * bit offset.
4352 *
4353 * Searching is performed through recursive exhaustive enumeration of all
4354 * fields of a struct/union. If there are any anonymous (embedded)
4355 * structs/unions, they are recursively searched as well. If field with
4356 * desired name is found, check compatibility between local and target types,
4357 * before returning result.
4358 *
4359 * 1 is returned, if field is found.
4360 * 0 is returned if no compatible field is found.
4361 * <0 is returned on error.
4362 */
4363static int bpf_core_match_member(const struct btf *local_btf,
4364				 const struct bpf_core_accessor *local_acc,
4365				 const struct btf *targ_btf,
4366				 __u32 targ_id,
4367				 struct bpf_core_spec *spec,
4368				 __u32 *next_targ_id)
4369{
4370	const struct btf_type *local_type, *targ_type;
4371	const struct btf_member *local_member, *m;
4372	const char *local_name, *targ_name;
4373	__u32 local_id;
4374	int i, n, found;
4375
4376	targ_type = skip_mods_and_typedefs(targ_btf, targ_id, &targ_id);
4377	if (!targ_type)
4378		return -EINVAL;
4379	if (!btf_is_composite(targ_type))
4380		return 0;
4381
4382	local_id = local_acc->type_id;
4383	local_type = btf__type_by_id(local_btf, local_id);
4384	local_member = btf_members(local_type) + local_acc->idx;
4385	local_name = btf__name_by_offset(local_btf, local_member->name_off);
4386
4387	n = btf_vlen(targ_type);
4388	m = btf_members(targ_type);
4389	for (i = 0; i < n; i++, m++) {
4390		__u32 bit_offset;
4391
4392		bit_offset = btf_member_bit_offset(targ_type, i);
4393
4394		/* too deep struct/union/array nesting */
4395		if (spec->raw_len == BPF_CORE_SPEC_MAX_LEN)
4396			return -E2BIG;
4397
4398		/* speculate this member will be the good one */
4399		spec->bit_offset += bit_offset;
4400		spec->raw_spec[spec->raw_len++] = i;
4401
4402		targ_name = btf__name_by_offset(targ_btf, m->name_off);
4403		if (str_is_empty(targ_name)) {
4404			/* embedded struct/union, we need to go deeper */
4405			found = bpf_core_match_member(local_btf, local_acc,
4406						      targ_btf, m->type,
4407						      spec, next_targ_id);
4408			if (found) /* either found or error */
4409				return found;
4410		} else if (strcmp(local_name, targ_name) == 0) {
4411			/* matching named field */
4412			struct bpf_core_accessor *targ_acc;
4413
4414			targ_acc = &spec->spec[spec->len++];
4415			targ_acc->type_id = targ_id;
4416			targ_acc->idx = i;
4417			targ_acc->name = targ_name;
4418
4419			*next_targ_id = m->type;
4420			found = bpf_core_fields_are_compat(local_btf,
4421							   local_member->type,
4422							   targ_btf, m->type);
4423			if (!found)
4424				spec->len--; /* pop accessor */
4425			return found;
4426		}
4427		/* member turned out not to be what we looked for */
4428		spec->bit_offset -= bit_offset;
4429		spec->raw_len--;
4430	}
4431
4432	return 0;
4433}
4434
4435/*
4436 * Try to match local spec to a target type and, if successful, produce full
4437 * target spec (high-level, low-level + bit offset).
4438 */
4439static int bpf_core_spec_match(struct bpf_core_spec *local_spec,
4440			       const struct btf *targ_btf, __u32 targ_id,
4441			       struct bpf_core_spec *targ_spec)
4442{
4443	const struct btf_type *targ_type;
4444	const struct bpf_core_accessor *local_acc;
4445	struct bpf_core_accessor *targ_acc;
4446	int i, sz, matched;
4447
4448	memset(targ_spec, 0, sizeof(*targ_spec));
4449	targ_spec->btf = targ_btf;
4450
4451	local_acc = &local_spec->spec[0];
4452	targ_acc = &targ_spec->spec[0];
4453
4454	for (i = 0; i < local_spec->len; i++, local_acc++, targ_acc++) {
4455		targ_type = skip_mods_and_typedefs(targ_spec->btf, targ_id,
4456						   &targ_id);
4457		if (!targ_type)
4458			return -EINVAL;
4459
4460		if (local_acc->name) {
4461			matched = bpf_core_match_member(local_spec->btf,
4462							local_acc,
4463							targ_btf, targ_id,
4464							targ_spec, &targ_id);
4465			if (matched <= 0)
4466				return matched;
4467		} else {
4468			/* for i=0, targ_id is already treated as array element
4469			 * type (because it's the original struct), for others
4470			 * we should find array element type first
4471			 */
4472			if (i > 0) {
4473				const struct btf_array *a;
4474				bool flex;
4475
4476				if (!btf_is_array(targ_type))
4477					return 0;
4478
4479				a = btf_array(targ_type);
4480				flex = is_flex_arr(targ_btf, targ_acc - 1, a);
4481				if (!flex && local_acc->idx >= a->nelems)
4482					return 0;
4483				if (!skip_mods_and_typedefs(targ_btf, a->type,
4484							    &targ_id))
4485					return -EINVAL;
4486			}
4487
4488			/* too deep struct/union/array nesting */
4489			if (targ_spec->raw_len == BPF_CORE_SPEC_MAX_LEN)
4490				return -E2BIG;
4491
4492			targ_acc->type_id = targ_id;
4493			targ_acc->idx = local_acc->idx;
4494			targ_acc->name = NULL;
4495			targ_spec->len++;
4496			targ_spec->raw_spec[targ_spec->raw_len] = targ_acc->idx;
4497			targ_spec->raw_len++;
4498
4499			sz = btf__resolve_size(targ_btf, targ_id);
4500			if (sz < 0)
4501				return sz;
4502			targ_spec->bit_offset += local_acc->idx * sz * 8;
4503		}
4504	}
4505
4506	return 1;
4507}
4508
4509static int bpf_core_calc_field_relo(const struct bpf_program *prog,
4510				    const struct bpf_field_reloc *relo,
4511				    const struct bpf_core_spec *spec,
4512				    __u32 *val, bool *validate)
4513{
4514	const struct bpf_core_accessor *acc = &spec->spec[spec->len - 1];
4515	const struct btf_type *t = btf__type_by_id(spec->btf, acc->type_id);
4516	__u32 byte_off, byte_sz, bit_off, bit_sz;
4517	const struct btf_member *m;
4518	const struct btf_type *mt;
4519	bool bitfield;
4520	__s64 sz;
4521
4522	/* a[n] accessor needs special handling */
4523	if (!acc->name) {
4524		if (relo->kind == BPF_FIELD_BYTE_OFFSET) {
4525			*val = spec->bit_offset / 8;
4526		} else if (relo->kind == BPF_FIELD_BYTE_SIZE) {
4527			sz = btf__resolve_size(spec->btf, acc->type_id);
4528			if (sz < 0)
4529				return -EINVAL;
4530			*val = sz;
4531		} else {
4532			pr_warn("prog '%s': relo %d at insn #%d can't be applied to array access\n",
4533				bpf_program__title(prog, false),
4534				relo->kind, relo->insn_off / 8);
4535			return -EINVAL;
4536		}
4537		if (validate)
4538			*validate = true;
4539		return 0;
4540	}
4541
4542	m = btf_members(t) + acc->idx;
4543	mt = skip_mods_and_typedefs(spec->btf, m->type, NULL);
4544	bit_off = spec->bit_offset;
4545	bit_sz = btf_member_bitfield_size(t, acc->idx);
4546
4547	bitfield = bit_sz > 0;
4548	if (bitfield) {
4549		byte_sz = mt->size;
4550		byte_off = bit_off / 8 / byte_sz * byte_sz;
4551		/* figure out smallest int size necessary for bitfield load */
4552		while (bit_off + bit_sz - byte_off * 8 > byte_sz * 8) {
4553			if (byte_sz >= 8) {
4554				/* bitfield can't be read with 64-bit read */
4555				pr_warn("prog '%s': relo %d at insn #%d can't be satisfied for bitfield\n",
4556					bpf_program__title(prog, false),
4557					relo->kind, relo->insn_off / 8);
4558				return -E2BIG;
4559			}
4560			byte_sz *= 2;
4561			byte_off = bit_off / 8 / byte_sz * byte_sz;
4562		}
4563	} else {
4564		sz = btf__resolve_size(spec->btf, m->type);
4565		if (sz < 0)
4566			return -EINVAL;
4567		byte_sz = sz;
4568		byte_off = spec->bit_offset / 8;
4569		bit_sz = byte_sz * 8;
4570	}
4571
4572	/* for bitfields, all the relocatable aspects are ambiguous and we
4573	 * might disagree with compiler, so turn off validation of expected
4574	 * value, except for signedness
4575	 */
4576	if (validate)
4577		*validate = !bitfield;
4578
4579	switch (relo->kind) {
4580	case BPF_FIELD_BYTE_OFFSET:
4581		*val = byte_off;
4582		break;
4583	case BPF_FIELD_BYTE_SIZE:
4584		*val = byte_sz;
4585		break;
4586	case BPF_FIELD_SIGNED:
4587		/* enums will be assumed unsigned */
4588		*val = btf_is_enum(mt) ||
4589		       (btf_int_encoding(mt) & BTF_INT_SIGNED);
4590		if (validate)
4591			*validate = true; /* signedness is never ambiguous */
4592		break;
4593	case BPF_FIELD_LSHIFT_U64:
4594#if __BYTE_ORDER == __LITTLE_ENDIAN
4595		*val = 64 - (bit_off + bit_sz - byte_off  * 8);
4596#else
4597		*val = (8 - byte_sz) * 8 + (bit_off - byte_off * 8);
4598#endif
4599		break;
4600	case BPF_FIELD_RSHIFT_U64:
4601		*val = 64 - bit_sz;
4602		if (validate)
4603			*validate = true; /* right shift is never ambiguous */
4604		break;
4605	case BPF_FIELD_EXISTS:
4606	default:
4607		pr_warn("prog '%s': unknown relo %d at insn #%d\n",
4608			bpf_program__title(prog, false),
4609			relo->kind, relo->insn_off / 8);
4610		return -EINVAL;
4611	}
4612
4613	return 0;
4614}
4615
4616/*
4617 * Patch relocatable BPF instruction.
4618 *
4619 * Patched value is determined by relocation kind and target specification.
4620 * For field existence relocation target spec will be NULL if field is not
4621 * found.
4622 * Expected insn->imm value is determined using relocation kind and local
4623 * spec, and is checked before patching instruction. If actual insn->imm value
4624 * is wrong, bail out with error.
4625 *
4626 * Currently three kinds of BPF instructions are supported:
4627 * 1. rX = <imm> (assignment with immediate operand);
4628 * 2. rX += <imm> (arithmetic operations with immediate operand);
4629 */
4630static int bpf_core_reloc_insn(struct bpf_program *prog,
4631			       const struct bpf_field_reloc *relo,
4632			       int relo_idx,
4633			       const struct bpf_core_spec *local_spec,
4634			       const struct bpf_core_spec *targ_spec)
4635{
4636	__u32 orig_val, new_val;
4637	struct bpf_insn *insn;
4638	bool validate = true;
4639	int insn_idx, err;
4640	__u8 class;
4641
4642	if (relo->insn_off % sizeof(struct bpf_insn))
4643		return -EINVAL;
4644	insn_idx = relo->insn_off / sizeof(struct bpf_insn);
4645	insn = &prog->insns[insn_idx];
4646	class = BPF_CLASS(insn->code);
4647
4648	if (relo->kind == BPF_FIELD_EXISTS) {
4649		orig_val = 1; /* can't generate EXISTS relo w/o local field */
4650		new_val = targ_spec ? 1 : 0;
4651	} else if (!targ_spec) {
4652		pr_debug("prog '%s': relo #%d: substituting insn #%d w/ invalid insn\n",
4653			 bpf_program__title(prog, false), relo_idx, insn_idx);
4654		insn->code = BPF_JMP | BPF_CALL;
4655		insn->dst_reg = 0;
4656		insn->src_reg = 0;
4657		insn->off = 0;
4658		/* if this instruction is reachable (not a dead code),
4659		 * verifier will complain with the following message:
4660		 * invalid func unknown#195896080
4661		 */
4662		insn->imm = 195896080; /* => 0xbad2310 => "bad relo" */
4663		return 0;
4664	} else {
4665		err = bpf_core_calc_field_relo(prog, relo, local_spec,
4666					       &orig_val, &validate);
4667		if (err)
4668			return err;
4669		err = bpf_core_calc_field_relo(prog, relo, targ_spec,
4670					       &new_val, NULL);
4671		if (err)
4672			return err;
4673	}
4674
4675	switch (class) {
4676	case BPF_ALU:
4677	case BPF_ALU64:
4678		if (BPF_SRC(insn->code) != BPF_K)
4679			return -EINVAL;
4680		if (validate && insn->imm != orig_val) {
4681			pr_warn("prog '%s': relo #%d: unexpected insn #%d (ALU/ALU64) value: got %u, exp %u -> %u\n",
4682				bpf_program__title(prog, false), relo_idx,
4683				insn_idx, insn->imm, orig_val, new_val);
4684			return -EINVAL;
4685		}
4686		orig_val = insn->imm;
4687		insn->imm = new_val;
4688		pr_debug("prog '%s': relo #%d: patched insn #%d (ALU/ALU64) imm %u -> %u\n",
4689			 bpf_program__title(prog, false), relo_idx, insn_idx,
4690			 orig_val, new_val);
4691		break;
4692	case BPF_LDX:
4693	case BPF_ST:
4694	case BPF_STX:
4695		if (validate && insn->off != orig_val) {
4696			pr_warn("prog '%s': relo #%d: unexpected insn #%d (LD/LDX/ST/STX) value: got %u, exp %u -> %u\n",
4697				bpf_program__title(prog, false), relo_idx,
4698				insn_idx, insn->off, orig_val, new_val);
4699			return -EINVAL;
4700		}
4701		if (new_val > SHRT_MAX) {
4702			pr_warn("prog '%s': relo #%d: insn #%d (LDX/ST/STX) value too big: %u\n",
4703				bpf_program__title(prog, false), relo_idx,
4704				insn_idx, new_val);
4705			return -ERANGE;
4706		}
4707		orig_val = insn->off;
4708		insn->off = new_val;
4709		pr_debug("prog '%s': relo #%d: patched insn #%d (LDX/ST/STX) off %u -> %u\n",
4710			 bpf_program__title(prog, false), relo_idx, insn_idx,
4711			 orig_val, new_val);
4712		break;
4713	default:
4714		pr_warn("prog '%s': relo #%d: trying to relocate unrecognized insn #%d, code:%x, src:%x, dst:%x, off:%x, imm:%x\n",
4715			bpf_program__title(prog, false), relo_idx,
4716			insn_idx, insn->code, insn->src_reg, insn->dst_reg,
4717			insn->off, insn->imm);
4718		return -EINVAL;
4719	}
4720
4721	return 0;
4722}
4723
4724/* Output spec definition in the format:
4725 * [<type-id>] (<type-name>) + <raw-spec> => <offset>@<spec>,
4726 * where <spec> is a C-syntax view of recorded field access, e.g.: x.a[3].b
4727 */
4728static void bpf_core_dump_spec(int level, const struct bpf_core_spec *spec)
4729{
4730	const struct btf_type *t;
4731	const char *s;
4732	__u32 type_id;
4733	int i;
4734
4735	type_id = spec->spec[0].type_id;
4736	t = btf__type_by_id(spec->btf, type_id);
4737	s = btf__name_by_offset(spec->btf, t->name_off);
4738	libbpf_print(level, "[%u] %s + ", type_id, s);
4739
4740	for (i = 0; i < spec->raw_len; i++)
4741		libbpf_print(level, "%d%s", spec->raw_spec[i],
4742			     i == spec->raw_len - 1 ? " => " : ":");
4743
4744	libbpf_print(level, "%u.%u @ &x",
4745		     spec->bit_offset / 8, spec->bit_offset % 8);
4746
4747	for (i = 0; i < spec->len; i++) {
4748		if (spec->spec[i].name)
4749			libbpf_print(level, ".%s", spec->spec[i].name);
4750		else
4751			libbpf_print(level, "[%u]", spec->spec[i].idx);
4752	}
4753
4754}
4755
4756static size_t bpf_core_hash_fn(const void *key, void *ctx)
4757{
4758	return (size_t)key;
4759}
4760
4761static bool bpf_core_equal_fn(const void *k1, const void *k2, void *ctx)
4762{
4763	return k1 == k2;
4764}
4765
4766static void *u32_as_hash_key(__u32 x)
4767{
4768	return (void *)(uintptr_t)x;
4769}
4770
4771/*
4772 * CO-RE relocate single instruction.
4773 *
4774 * The outline and important points of the algorithm:
4775 * 1. For given local type, find corresponding candidate target types.
4776 *    Candidate type is a type with the same "essential" name, ignoring
4777 *    everything after last triple underscore (___). E.g., `sample`,
4778 *    `sample___flavor_one`, `sample___flavor_another_one`, are all candidates
4779 *    for each other. Names with triple underscore are referred to as
4780 *    "flavors" and are useful, among other things, to allow to
4781 *    specify/support incompatible variations of the same kernel struct, which
4782 *    might differ between different kernel versions and/or build
4783 *    configurations.
4784 *
4785 *    N.B. Struct "flavors" could be generated by bpftool's BTF-to-C
4786 *    converter, when deduplicated BTF of a kernel still contains more than
4787 *    one different types with the same name. In that case, ___2, ___3, etc
4788 *    are appended starting from second name conflict. But start flavors are
4789 *    also useful to be defined "locally", in BPF program, to extract same
4790 *    data from incompatible changes between different kernel
4791 *    versions/configurations. For instance, to handle field renames between
4792 *    kernel versions, one can use two flavors of the struct name with the
4793 *    same common name and use conditional relocations to extract that field,
4794 *    depending on target kernel version.
4795 * 2. For each candidate type, try to match local specification to this
4796 *    candidate target type. Matching involves finding corresponding
4797 *    high-level spec accessors, meaning that all named fields should match,
4798 *    as well as all array accesses should be within the actual bounds. Also,
4799 *    types should be compatible (see bpf_core_fields_are_compat for details).
4800 * 3. It is supported and expected that there might be multiple flavors
4801 *    matching the spec. As long as all the specs resolve to the same set of
4802 *    offsets across all candidates, there is no error. If there is any
4803 *    ambiguity, CO-RE relocation will fail. This is necessary to accomodate
4804 *    imprefection of BTF deduplication, which can cause slight duplication of
4805 *    the same BTF type, if some directly or indirectly referenced (by
4806 *    pointer) type gets resolved to different actual types in different
4807 *    object files. If such situation occurs, deduplicated BTF will end up
4808 *    with two (or more) structurally identical types, which differ only in
4809 *    types they refer to through pointer. This should be OK in most cases and
4810 *    is not an error.
4811 * 4. Candidate types search is performed by linearly scanning through all
4812 *    types in target BTF. It is anticipated that this is overall more
4813 *    efficient memory-wise and not significantly worse (if not better)
4814 *    CPU-wise compared to prebuilding a map from all local type names to
4815 *    a list of candidate type names. It's also sped up by caching resolved
4816 *    list of matching candidates per each local "root" type ID, that has at
4817 *    least one bpf_field_reloc associated with it. This list is shared
4818 *    between multiple relocations for the same type ID and is updated as some
4819 *    of the candidates are pruned due to structural incompatibility.
4820 */
4821static int bpf_core_reloc_field(struct bpf_program *prog,
4822				 const struct bpf_field_reloc *relo,
4823				 int relo_idx,
4824				 const struct btf *local_btf,
4825				 const struct btf *targ_btf,
4826				 struct hashmap *cand_cache)
4827{
4828	const char *prog_name = bpf_program__title(prog, false);
4829	struct bpf_core_spec local_spec, cand_spec, targ_spec;
4830	const void *type_key = u32_as_hash_key(relo->type_id);
4831	const struct btf_type *local_type, *cand_type;
4832	const char *local_name, *cand_name;
4833	struct ids_vec *cand_ids;
4834	__u32 local_id, cand_id;
4835	const char *spec_str;
4836	int i, j, err;
4837
4838	local_id = relo->type_id;
4839	local_type = btf__type_by_id(local_btf, local_id);
4840	if (!local_type)
4841		return -EINVAL;
4842
4843	local_name = btf__name_by_offset(local_btf, local_type->name_off);
4844	if (str_is_empty(local_name))
4845		return -EINVAL;
4846
4847	spec_str = btf__name_by_offset(local_btf, relo->access_str_off);
4848	if (str_is_empty(spec_str))
4849		return -EINVAL;
4850
4851	err = bpf_core_spec_parse(local_btf, local_id, spec_str, &local_spec);
4852	if (err) {
4853		pr_warn("prog '%s': relo #%d: parsing [%d] %s + %s failed: %d\n",
4854			prog_name, relo_idx, local_id, local_name, spec_str,
4855			err);
4856		return -EINVAL;
4857	}
4858
4859	pr_debug("prog '%s': relo #%d: kind %d, spec is ", prog_name, relo_idx,
4860		 relo->kind);
4861	bpf_core_dump_spec(LIBBPF_DEBUG, &local_spec);
4862	libbpf_print(LIBBPF_DEBUG, "\n");
4863
4864	if (!hashmap__find(cand_cache, type_key, (void **)&cand_ids)) {
4865		cand_ids = bpf_core_find_cands(local_btf, local_id, targ_btf);
4866		if (IS_ERR(cand_ids)) {
4867			pr_warn("prog '%s': relo #%d: target candidate search failed for [%d] %s: %ld",
4868				prog_name, relo_idx, local_id, local_name,
4869				PTR_ERR(cand_ids));
4870			return PTR_ERR(cand_ids);
4871		}
4872		err = hashmap__set(cand_cache, type_key, cand_ids, NULL, NULL);
4873		if (err) {
4874			bpf_core_free_cands(cand_ids);
4875			return err;
4876		}
4877	}
4878
4879	for (i = 0, j = 0; i < cand_ids->len; i++) {
4880		cand_id = cand_ids->data[i];
4881		cand_type = btf__type_by_id(targ_btf, cand_id);
4882		cand_name = btf__name_by_offset(targ_btf, cand_type->name_off);
4883
4884		err = bpf_core_spec_match(&local_spec, targ_btf,
4885					  cand_id, &cand_spec);
4886		pr_debug("prog '%s': relo #%d: matching candidate #%d %s against spec ",
4887			 prog_name, relo_idx, i, cand_name);
4888		bpf_core_dump_spec(LIBBPF_DEBUG, &cand_spec);
4889		libbpf_print(LIBBPF_DEBUG, ": %d\n", err);
4890		if (err < 0) {
4891			pr_warn("prog '%s': relo #%d: matching error: %d\n",
4892				prog_name, relo_idx, err);
4893			return err;
4894		}
4895		if (err == 0)
4896			continue;
4897
4898		if (j == 0) {
4899			targ_spec = cand_spec;
4900		} else if (cand_spec.bit_offset != targ_spec.bit_offset) {
4901			/* if there are many candidates, they should all
4902			 * resolve to the same bit offset
4903			 */
4904			pr_warn("prog '%s': relo #%d: offset ambiguity: %u != %u\n",
4905				prog_name, relo_idx, cand_spec.bit_offset,
4906				targ_spec.bit_offset);
4907			return -EINVAL;
4908		}
4909
4910		cand_ids->data[j++] = cand_spec.spec[0].type_id;
4911	}
4912
4913	/*
4914	 * For BPF_FIELD_EXISTS relo or when used BPF program has field
4915	 * existence checks or kernel version/config checks, it's expected
4916	 * that we might not find any candidates. In this case, if field
4917	 * wasn't found in any candidate, the list of candidates shouldn't
4918	 * change at all, we'll just handle relocating appropriately,
4919	 * depending on relo's kind.
4920	 */
4921	if (j > 0)
4922		cand_ids->len = j;
4923
4924	/*
4925	 * If no candidates were found, it might be both a programmer error,
4926	 * as well as expected case, depending whether instruction w/
4927	 * relocation is guarded in some way that makes it unreachable (dead
4928	 * code) if relocation can't be resolved. This is handled in
4929	 * bpf_core_reloc_insn() uniformly by replacing that instruction with
4930	 * BPF helper call insn (using invalid helper ID). If that instruction
4931	 * is indeed unreachable, then it will be ignored and eliminated by
4932	 * verifier. If it was an error, then verifier will complain and point
4933	 * to a specific instruction number in its log.
4934	 */
4935	if (j == 0)
4936		pr_debug("prog '%s': relo #%d: no matching targets found for [%d] %s + %s\n",
4937			 prog_name, relo_idx, local_id, local_name, spec_str);
4938
4939	/* bpf_core_reloc_insn should know how to handle missing targ_spec */
4940	err = bpf_core_reloc_insn(prog, relo, relo_idx, &local_spec,
4941				  j ? &targ_spec : NULL);
4942	if (err) {
4943		pr_warn("prog '%s': relo #%d: failed to patch insn at offset %d: %d\n",
4944			prog_name, relo_idx, relo->insn_off, err);
4945		return -EINVAL;
4946	}
4947
4948	return 0;
4949}
4950
4951static int
4952bpf_core_reloc_fields(struct bpf_object *obj, const char *targ_btf_path)
4953{
4954	const struct btf_ext_info_sec *sec;
4955	const struct bpf_field_reloc *rec;
4956	const struct btf_ext_info *seg;
4957	struct hashmap_entry *entry;
4958	struct hashmap *cand_cache = NULL;
4959	struct bpf_program *prog;
4960	struct btf *targ_btf;
4961	const char *sec_name;
4962	int i, err = 0;
4963
4964	if (targ_btf_path)
4965		targ_btf = btf__parse_elf(targ_btf_path, NULL);
4966	else
4967		targ_btf = obj->btf_vmlinux;
4968	if (IS_ERR_OR_NULL(targ_btf)) {
4969		pr_warn("failed to get target BTF: %ld\n", PTR_ERR(targ_btf));
4970		return PTR_ERR(targ_btf);
4971	}
4972
4973	cand_cache = hashmap__new(bpf_core_hash_fn, bpf_core_equal_fn, NULL);
4974	if (IS_ERR(cand_cache)) {
4975		err = PTR_ERR(cand_cache);
4976		goto out;
4977	}
4978
4979	seg = &obj->btf_ext->field_reloc_info;
4980	for_each_btf_ext_sec(seg, sec) {
4981		sec_name = btf__name_by_offset(obj->btf, sec->sec_name_off);
4982		if (str_is_empty(sec_name)) {
4983			err = -EINVAL;
4984			goto out;
4985		}
4986		prog = NULL;
4987		for (i = 0; i < obj->nr_programs; i++) {
4988			if (!strcmp(obj->programs[i].section_name, sec_name)) {
4989				prog = &obj->programs[i];
4990				break;
4991			}
4992		}
4993		if (!prog) {
4994			pr_warn("failed to find program '%s' for CO-RE offset relocation\n",
4995				sec_name);
4996			err = -EINVAL;
4997			goto out;
4998		}
4999
5000		pr_debug("prog '%s': performing %d CO-RE offset relocs\n",
5001			 sec_name, sec->num_info);
5002
5003		for_each_btf_ext_rec(seg, sec, i, rec) {
5004			err = bpf_core_reloc_field(prog, rec, i, obj->btf,
5005						   targ_btf, cand_cache);
5006			if (err) {
5007				pr_warn("prog '%s': relo #%d: failed to relocate: %d\n",
5008					sec_name, i, err);
5009				goto out;
5010			}
5011		}
5012	}
5013
5014out:
5015	/* obj->btf_vmlinux is freed at the end of object load phase */
5016	if (targ_btf != obj->btf_vmlinux)
5017		btf__free(targ_btf);
5018	if (!IS_ERR_OR_NULL(cand_cache)) {
5019		hashmap__for_each_entry(cand_cache, entry, i) {
5020			bpf_core_free_cands(entry->value);
5021		}
5022		hashmap__free(cand_cache);
5023	}
5024	return err;
5025}
5026
5027static int
5028bpf_object__relocate_core(struct bpf_object *obj, const char *targ_btf_path)
5029{
5030	int err = 0;
5031
5032	if (obj->btf_ext->field_reloc_info.len)
5033		err = bpf_core_reloc_fields(obj, targ_btf_path);
5034
5035	return err;
5036}
5037
5038static int
5039bpf_program__reloc_text(struct bpf_program *prog, struct bpf_object *obj,
5040			struct reloc_desc *relo)
5041{
5042	struct bpf_insn *insn, *new_insn;
5043	struct bpf_program *text;
5044	size_t new_cnt;
5045	int err;
5046
5047	if (prog->idx != obj->efile.text_shndx && prog->main_prog_cnt == 0) {
5048		text = bpf_object__find_prog_by_idx(obj, obj->efile.text_shndx);
5049		if (!text) {
5050			pr_warn("no .text section found yet relo into text exist\n");
5051			return -LIBBPF_ERRNO__RELOC;
5052		}
5053		new_cnt = prog->insns_cnt + text->insns_cnt;
5054		new_insn = reallocarray(prog->insns, new_cnt, sizeof(*insn));
5055		if (!new_insn) {
5056			pr_warn("oom in prog realloc\n");
5057			return -ENOMEM;
5058		}
5059		prog->insns = new_insn;
5060
5061		if (obj->btf_ext) {
5062			err = bpf_program_reloc_btf_ext(prog, obj,
5063							text->section_name,
5064							prog->insns_cnt);
5065			if (err)
5066				return err;
5067		}
5068
5069		memcpy(new_insn + prog->insns_cnt, text->insns,
5070		       text->insns_cnt * sizeof(*insn));
5071		prog->main_prog_cnt = prog->insns_cnt;
5072		prog->insns_cnt = new_cnt;
5073		pr_debug("added %zd insn from %s to prog %s\n",
5074			 text->insns_cnt, text->section_name,
5075			 prog->section_name);
5076	}
5077
5078	insn = &prog->insns[relo->insn_idx];
5079	insn->imm += relo->sym_off / 8 + prog->main_prog_cnt - relo->insn_idx;
5080	return 0;
5081}
5082
5083static int
5084bpf_program__relocate(struct bpf_program *prog, struct bpf_object *obj)
5085{
5086	int i, err;
5087
5088	if (!prog)
5089		return 0;
5090
5091	if (obj->btf_ext) {
5092		err = bpf_program_reloc_btf_ext(prog, obj,
5093						prog->section_name, 0);
5094		if (err)
5095			return err;
5096	}
5097
5098	if (!prog->reloc_desc)
5099		return 0;
5100
5101	for (i = 0; i < prog->nr_reloc; i++) {
5102		struct reloc_desc *relo = &prog->reloc_desc[i];
5103		struct bpf_insn *insn = &prog->insns[relo->insn_idx];
5104		struct extern_desc *ext;
5105
5106		if (relo->insn_idx + 1 >= (int)prog->insns_cnt) {
5107			pr_warn("relocation out of range: '%s'\n",
5108				prog->section_name);
5109			return -LIBBPF_ERRNO__RELOC;
5110		}
5111
5112		switch (relo->type) {
5113		case RELO_LD64:
5114			insn[0].src_reg = BPF_PSEUDO_MAP_FD;
5115			insn[0].imm = obj->maps[relo->map_idx].fd;
5116			break;
5117		case RELO_DATA:
5118			insn[0].src_reg = BPF_PSEUDO_MAP_VALUE;
5119			insn[1].imm = insn[0].imm + relo->sym_off;
5120			insn[0].imm = obj->maps[relo->map_idx].fd;
5121			break;
5122		case RELO_EXTERN:
5123			ext = &obj->externs[relo->sym_off];
5124			if (ext->type == EXT_KCFG) {
5125				insn[0].src_reg = BPF_PSEUDO_MAP_VALUE;
5126				insn[0].imm = obj->maps[obj->kconfig_map_idx].fd;
5127				insn[1].imm = ext->kcfg.data_off;
5128			} else /* EXT_KSYM */ {
5129				insn[0].imm = (__u32)ext->ksym.addr;
5130				insn[1].imm = ext->ksym.addr >> 32;
5131			}
5132			break;
5133		case RELO_CALL:
5134			err = bpf_program__reloc_text(prog, obj, relo);
5135			if (err)
5136				return err;
5137			break;
5138		default:
5139			pr_warn("relo #%d: bad relo type %d\n", i, relo->type);
5140			return -EINVAL;
5141		}
5142	}
5143
5144	zfree(&prog->reloc_desc);
5145	prog->nr_reloc = 0;
5146	return 0;
5147}
5148
 
5149static int
5150bpf_object__relocate(struct bpf_object *obj, const char *targ_btf_path)
5151{
5152	struct bpf_program *prog;
5153	size_t i;
5154	int err;
5155
5156	if (obj->btf_ext) {
5157		err = bpf_object__relocate_core(obj, targ_btf_path);
5158		if (err) {
5159			pr_warn("failed to perform CO-RE relocations: %d\n",
5160				err);
5161			return err;
5162		}
5163	}
5164	/* ensure .text is relocated first, as it's going to be copied as-is
5165	 * later for sub-program calls
5166	 */
5167	for (i = 0; i < obj->nr_programs; i++) {
5168		prog = &obj->programs[i];
5169		if (prog->idx != obj->efile.text_shndx)
5170			continue;
5171
5172		err = bpf_program__relocate(prog, obj);
5173		if (err) {
5174			pr_warn("failed to relocate '%s'\n", prog->section_name);
 
5175			return err;
5176		}
5177		break;
5178	}
5179	/* now relocate everything but .text, which by now is relocated
5180	 * properly, so we can copy raw sub-program instructions as is safely
5181	 */
5182	for (i = 0; i < obj->nr_programs; i++) {
5183		prog = &obj->programs[i];
5184		if (prog->idx == obj->efile.text_shndx)
5185			continue;
5186
5187		err = bpf_program__relocate(prog, obj);
5188		if (err) {
5189			pr_warn("failed to relocate '%s'\n", prog->section_name);
5190			return err;
5191		}
5192	}
5193	return 0;
5194}
5195
5196static int bpf_object__collect_st_ops_relos(struct bpf_object *obj,
5197					    GElf_Shdr *shdr, Elf_Data *data);
5198
5199static int bpf_object__collect_map_relos(struct bpf_object *obj,
5200					 GElf_Shdr *shdr, Elf_Data *data)
5201{
5202	const int bpf_ptr_sz = 8, host_ptr_sz = sizeof(void *);
5203	int i, j, nrels, new_sz;
5204	const struct btf_var_secinfo *vi = NULL;
5205	const struct btf_type *sec, *var, *def;
5206	struct bpf_map *map = NULL, *targ_map;
5207	const struct btf_member *member;
5208	const char *name, *mname;
5209	Elf_Data *symbols;
5210	unsigned int moff;
5211	GElf_Sym sym;
5212	GElf_Rel rel;
5213	void *tmp;
5214
5215	if (!obj->efile.btf_maps_sec_btf_id || !obj->btf)
5216		return -EINVAL;
5217	sec = btf__type_by_id(obj->btf, obj->efile.btf_maps_sec_btf_id);
5218	if (!sec)
5219		return -EINVAL;
5220
5221	symbols = obj->efile.symbols;
5222	nrels = shdr->sh_size / shdr->sh_entsize;
5223	for (i = 0; i < nrels; i++) {
5224		if (!gelf_getrel(data, i, &rel)) {
5225			pr_warn(".maps relo #%d: failed to get ELF relo\n", i);
5226			return -LIBBPF_ERRNO__FORMAT;
5227		}
5228		if (!gelf_getsym(symbols, GELF_R_SYM(rel.r_info), &sym)) {
5229			pr_warn(".maps relo #%d: symbol %zx not found\n",
5230				i, (size_t)GELF_R_SYM(rel.r_info));
5231			return -LIBBPF_ERRNO__FORMAT;
5232		}
5233		name = elf_strptr(obj->efile.elf, obj->efile.strtabidx,
5234				  sym.st_name) ? : "<?>";
5235		if (sym.st_shndx != obj->efile.btf_maps_shndx) {
5236			pr_warn(".maps relo #%d: '%s' isn't a BTF-defined map\n",
5237				i, name);
5238			return -LIBBPF_ERRNO__RELOC;
5239		}
5240
5241		pr_debug(".maps relo #%d: for %zd value %zd rel.r_offset %zu name %d ('%s')\n",
5242			 i, (ssize_t)(rel.r_info >> 32), (size_t)sym.st_value,
5243			 (size_t)rel.r_offset, sym.st_name, name);
5244
5245		for (j = 0; j < obj->nr_maps; j++) {
5246			map = &obj->maps[j];
5247			if (map->sec_idx != obj->efile.btf_maps_shndx)
5248				continue;
5249
5250			vi = btf_var_secinfos(sec) + map->btf_var_idx;
5251			if (vi->offset <= rel.r_offset &&
5252			    rel.r_offset + bpf_ptr_sz <= vi->offset + vi->size)
5253				break;
5254		}
5255		if (j == obj->nr_maps) {
5256			pr_warn(".maps relo #%d: cannot find map '%s' at rel.r_offset %zu\n",
5257				i, name, (size_t)rel.r_offset);
5258			return -EINVAL;
5259		}
5260
5261		if (!bpf_map_type__is_map_in_map(map->def.type))
5262			return -EINVAL;
5263		if (map->def.type == BPF_MAP_TYPE_HASH_OF_MAPS &&
5264		    map->def.key_size != sizeof(int)) {
5265			pr_warn(".maps relo #%d: hash-of-maps '%s' should have key size %zu.\n",
5266				i, map->name, sizeof(int));
5267			return -EINVAL;
5268		}
5269
5270		targ_map = bpf_object__find_map_by_name(obj, name);
5271		if (!targ_map)
5272			return -ESRCH;
5273
5274		var = btf__type_by_id(obj->btf, vi->type);
5275		def = skip_mods_and_typedefs(obj->btf, var->type, NULL);
5276		if (btf_vlen(def) == 0)
5277			return -EINVAL;
5278		member = btf_members(def) + btf_vlen(def) - 1;
5279		mname = btf__name_by_offset(obj->btf, member->name_off);
5280		if (strcmp(mname, "values"))
5281			return -EINVAL;
5282
5283		moff = btf_member_bit_offset(def, btf_vlen(def) - 1) / 8;
5284		if (rel.r_offset - vi->offset < moff)
5285			return -EINVAL;
5286
5287		moff = rel.r_offset - vi->offset - moff;
5288		/* here we use BPF pointer size, which is always 64 bit, as we
5289		 * are parsing ELF that was built for BPF target
5290		 */
5291		if (moff % bpf_ptr_sz)
5292			return -EINVAL;
5293		moff /= bpf_ptr_sz;
5294		if (moff >= map->init_slots_sz) {
5295			new_sz = moff + 1;
5296			tmp = realloc(map->init_slots, new_sz * host_ptr_sz);
5297			if (!tmp)
5298				return -ENOMEM;
5299			map->init_slots = tmp;
5300			memset(map->init_slots + map->init_slots_sz, 0,
5301			       (new_sz - map->init_slots_sz) * host_ptr_sz);
5302			map->init_slots_sz = new_sz;
5303		}
5304		map->init_slots[moff] = targ_map;
5305
5306		pr_debug(".maps relo #%d: map '%s' slot [%d] points to map '%s'\n",
5307			 i, map->name, moff, name);
5308	}
5309
5310	return 0;
5311}
5312
5313static int bpf_object__collect_reloc(struct bpf_object *obj)
5314{
5315	int i, err;
5316
5317	if (!obj_elf_valid(obj)) {
5318		pr_warn("Internal error: elf object is closed\n");
5319		return -LIBBPF_ERRNO__INTERNAL;
5320	}
5321
5322	for (i = 0; i < obj->efile.nr_reloc_sects; i++) {
5323		GElf_Shdr *shdr = &obj->efile.reloc_sects[i].shdr;
5324		Elf_Data *data = obj->efile.reloc_sects[i].data;
5325		int idx = shdr->sh_info;
5326		struct bpf_program *prog;
 
5327
5328		if (shdr->sh_type != SHT_REL) {
5329			pr_warn("internal error at %d\n", __LINE__);
5330			return -LIBBPF_ERRNO__INTERNAL;
5331		}
5332
5333		if (idx == obj->efile.st_ops_shndx) {
5334			err = bpf_object__collect_st_ops_relos(obj, shdr, data);
5335		} else if (idx == obj->efile.btf_maps_shndx) {
5336			err = bpf_object__collect_map_relos(obj, shdr, data);
5337		} else {
5338			prog = bpf_object__find_prog_by_idx(obj, idx);
5339			if (!prog) {
5340				pr_warn("relocation failed: no prog in section(%d)\n", idx);
5341				return -LIBBPF_ERRNO__RELOC;
5342			}
5343			err = bpf_program__collect_reloc(prog, shdr, data, obj);
5344		}
 
 
 
 
 
5345		if (err)
5346			return err;
5347	}
5348	return 0;
5349}
5350
5351static int
5352load_program(struct bpf_program *prog, struct bpf_insn *insns, int insns_cnt,
5353	     char *license, __u32 kern_version, int *pfd)
5354{
5355	struct bpf_load_program_attr load_attr;
5356	char *cp, errmsg[STRERR_BUFSIZE];
5357	size_t log_buf_size = 0;
5358	char *log_buf = NULL;
5359	int btf_fd, ret;
5360
5361	if (!insns || !insns_cnt)
5362		return -EINVAL;
5363
5364	memset(&load_attr, 0, sizeof(struct bpf_load_program_attr));
5365	load_attr.prog_type = prog->type;
5366	/* old kernels might not support specifying expected_attach_type */
5367	if (!prog->caps->exp_attach_type && prog->sec_def &&
5368	    prog->sec_def->is_exp_attach_type_optional)
5369		load_attr.expected_attach_type = 0;
5370	else
5371		load_attr.expected_attach_type = prog->expected_attach_type;
5372	if (prog->caps->name)
5373		load_attr.name = prog->name;
5374	load_attr.insns = insns;
5375	load_attr.insns_cnt = insns_cnt;
5376	load_attr.license = license;
5377	if (prog->type == BPF_PROG_TYPE_STRUCT_OPS ||
5378	    prog->type == BPF_PROG_TYPE_LSM) {
5379		load_attr.attach_btf_id = prog->attach_btf_id;
5380	} else if (prog->type == BPF_PROG_TYPE_TRACING ||
5381		   prog->type == BPF_PROG_TYPE_EXT) {
5382		load_attr.attach_prog_fd = prog->attach_prog_fd;
5383		load_attr.attach_btf_id = prog->attach_btf_id;
5384	} else {
5385		load_attr.kern_version = kern_version;
5386		load_attr.prog_ifindex = prog->prog_ifindex;
5387	}
5388	/* specify func_info/line_info only if kernel supports them */
5389	btf_fd = bpf_object__btf_fd(prog->obj);
5390	if (btf_fd >= 0 && prog->obj->caps.btf_func) {
5391		load_attr.prog_btf_fd = btf_fd;
5392		load_attr.func_info = prog->func_info;
5393		load_attr.func_info_rec_size = prog->func_info_rec_size;
5394		load_attr.func_info_cnt = prog->func_info_cnt;
5395		load_attr.line_info = prog->line_info;
5396		load_attr.line_info_rec_size = prog->line_info_rec_size;
5397		load_attr.line_info_cnt = prog->line_info_cnt;
5398	}
5399	load_attr.log_level = prog->log_level;
5400	load_attr.prog_flags = prog->prog_flags;
5401
5402retry_load:
5403	if (log_buf_size) {
5404		log_buf = malloc(log_buf_size);
5405		if (!log_buf)
5406			return -ENOMEM;
5407
5408		*log_buf = 0;
5409	}
5410
5411	ret = bpf_load_program_xattr(&load_attr, log_buf, log_buf_size);
 
5412
5413	if (ret >= 0) {
5414		if (log_buf && load_attr.log_level)
5415			pr_debug("verifier log:\n%s", log_buf);
5416		*pfd = ret;
5417		ret = 0;
5418		goto out;
5419	}
5420
5421	if (!log_buf || errno == ENOSPC) {
5422		log_buf_size = max((size_t)BPF_LOG_BUF_SIZE,
5423				   log_buf_size << 1);
5424
5425		free(log_buf);
5426		goto retry_load;
5427	}
5428	ret = -errno;
5429	cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg));
5430	pr_warn("load bpf program failed: %s\n", cp);
5431	pr_perm_msg(ret);
5432
5433	if (log_buf && log_buf[0] != '\0') {
5434		ret = -LIBBPF_ERRNO__VERIFY;
5435		pr_warn("-- BEGIN DUMP LOG ---\n");
5436		pr_warn("\n%s\n", log_buf);
5437		pr_warn("-- END LOG --\n");
5438	} else if (load_attr.insns_cnt >= BPF_MAXINSNS) {
5439		pr_warn("Program too large (%zu insns), at most %d insns\n",
5440			load_attr.insns_cnt, BPF_MAXINSNS);
5441		ret = -LIBBPF_ERRNO__PROG2BIG;
5442	} else if (load_attr.prog_type != BPF_PROG_TYPE_KPROBE) {
5443		/* Wrong program type? */
5444		int fd;
 
5445
5446		load_attr.prog_type = BPF_PROG_TYPE_KPROBE;
5447		load_attr.expected_attach_type = 0;
5448		fd = bpf_load_program_xattr(&load_attr, NULL, 0);
5449		if (fd >= 0) {
5450			close(fd);
5451			ret = -LIBBPF_ERRNO__PROGTYPE;
5452			goto out;
 
5453		}
 
 
 
5454	}
5455
5456out:
5457	free(log_buf);
5458	return ret;
5459}
5460
5461static int libbpf_find_attach_btf_id(struct bpf_program *prog);
5462
5463int bpf_program__load(struct bpf_program *prog, char *license, __u32 kern_ver)
5464{
5465	int err = 0, fd, i, btf_id;
5466
5467	if (prog->obj->loaded) {
5468		pr_warn("prog '%s'('%s'): can't load after object was loaded\n",
5469			prog->name, prog->section_name);
5470		return -EINVAL;
5471	}
5472
5473	if ((prog->type == BPF_PROG_TYPE_TRACING ||
5474	     prog->type == BPF_PROG_TYPE_LSM ||
5475	     prog->type == BPF_PROG_TYPE_EXT) && !prog->attach_btf_id) {
5476		btf_id = libbpf_find_attach_btf_id(prog);
5477		if (btf_id <= 0)
5478			return btf_id;
5479		prog->attach_btf_id = btf_id;
5480	}
5481
5482	if (prog->instances.nr < 0 || !prog->instances.fds) {
5483		if (prog->preprocessor) {
5484			pr_warn("Internal error: can't load program '%s'\n",
5485				prog->section_name);
5486			return -LIBBPF_ERRNO__INTERNAL;
5487		}
5488
5489		prog->instances.fds = malloc(sizeof(int));
5490		if (!prog->instances.fds) {
5491			pr_warn("Not enough memory for BPF fds\n");
5492			return -ENOMEM;
5493		}
5494		prog->instances.nr = 1;
5495		prog->instances.fds[0] = -1;
5496	}
5497
5498	if (!prog->preprocessor) {
5499		if (prog->instances.nr != 1) {
5500			pr_warn("Program '%s' is inconsistent: nr(%d) != 1\n",
5501				prog->section_name, prog->instances.nr);
5502		}
5503		err = load_program(prog, prog->insns, prog->insns_cnt,
5504				   license, kern_ver, &fd);
5505		if (!err)
5506			prog->instances.fds[0] = fd;
5507		goto out;
5508	}
5509
5510	for (i = 0; i < prog->instances.nr; i++) {
5511		struct bpf_prog_prep_result result;
5512		bpf_program_prep_t preprocessor = prog->preprocessor;
5513
5514		memset(&result, 0, sizeof(result));
5515		err = preprocessor(prog, i, prog->insns,
5516				   prog->insns_cnt, &result);
5517		if (err) {
5518			pr_warn("Preprocessing the %dth instance of program '%s' failed\n",
5519				i, prog->section_name);
5520			goto out;
5521		}
5522
5523		if (!result.new_insn_ptr || !result.new_insn_cnt) {
5524			pr_debug("Skip loading the %dth instance of program '%s'\n",
5525				 i, prog->section_name);
5526			prog->instances.fds[i] = -1;
5527			if (result.pfd)
5528				*result.pfd = -1;
5529			continue;
5530		}
5531
5532		err = load_program(prog, result.new_insn_ptr,
5533				   result.new_insn_cnt, license, kern_ver, &fd);
 
 
5534		if (err) {
5535			pr_warn("Loading the %dth instance of program '%s' failed\n",
5536				i, prog->section_name);
5537			goto out;
5538		}
5539
5540		if (result.pfd)
5541			*result.pfd = fd;
5542		prog->instances.fds[i] = fd;
5543	}
5544out:
5545	if (err)
5546		pr_warn("failed to load program '%s'\n", prog->section_name);
 
5547	zfree(&prog->insns);
5548	prog->insns_cnt = 0;
5549	return err;
5550}
5551
5552static bool bpf_program__is_function_storage(const struct bpf_program *prog,
5553					     const struct bpf_object *obj)
5554{
5555	return prog->idx == obj->efile.text_shndx && obj->has_pseudo_calls;
5556}
5557
5558static int
5559bpf_object__load_progs(struct bpf_object *obj, int log_level)
5560{
5561	struct bpf_program *prog;
5562	size_t i;
5563	int err;
5564
5565	for (i = 0; i < obj->nr_programs; i++) {
5566		prog = &obj->programs[i];
5567		if (bpf_program__is_function_storage(prog, obj))
5568			continue;
5569		if (!prog->load) {
5570			pr_debug("prog '%s'('%s'): skipped loading\n",
5571				 prog->name, prog->section_name);
5572			continue;
5573		}
5574		prog->log_level |= log_level;
5575		err = bpf_program__load(prog, obj->license, obj->kern_version);
5576		if (err)
5577			return err;
5578	}
5579	return 0;
5580}
5581
5582static const struct bpf_sec_def *find_sec_def(const char *sec_name);
 
 
 
 
 
 
 
 
5583
5584static struct bpf_object *
5585__bpf_object__open(const char *path, const void *obj_buf, size_t obj_buf_sz,
5586		   const struct bpf_object_open_opts *opts)
5587{
5588	const char *obj_name, *kconfig;
5589	struct bpf_program *prog;
5590	struct bpf_object *obj;
5591	char tmp_name[64];
5592	int err;
5593
5594	if (elf_version(EV_CURRENT) == EV_NONE) {
5595		pr_warn("failed to init libelf for %s\n",
5596			path ? : "(mem buf)");
5597		return ERR_PTR(-LIBBPF_ERRNO__LIBELF);
5598	}
5599
5600	if (!OPTS_VALID(opts, bpf_object_open_opts))
5601		return ERR_PTR(-EINVAL);
5602
5603	obj_name = OPTS_GET(opts, object_name, NULL);
5604	if (obj_buf) {
5605		if (!obj_name) {
5606			snprintf(tmp_name, sizeof(tmp_name), "%lx-%lx",
5607				 (unsigned long)obj_buf,
5608				 (unsigned long)obj_buf_sz);
5609			obj_name = tmp_name;
5610		}
5611		path = obj_name;
5612		pr_debug("loading object '%s' from buffer\n", obj_name);
5613	}
5614
5615	obj = bpf_object__new(path, obj_buf, obj_buf_sz, obj_name);
5616	if (IS_ERR(obj))
5617		return obj;
5618
5619	kconfig = OPTS_GET(opts, kconfig, NULL);
5620	if (kconfig) {
5621		obj->kconfig = strdup(kconfig);
5622		if (!obj->kconfig)
5623			return ERR_PTR(-ENOMEM);
5624	}
5625
5626	err = bpf_object__elf_init(obj);
5627	err = err ? : bpf_object__check_endianness(obj);
5628	err = err ? : bpf_object__elf_collect(obj);
5629	err = err ? : bpf_object__collect_externs(obj);
5630	err = err ? : bpf_object__finalize_btf(obj);
5631	err = err ? : bpf_object__init_maps(obj, opts);
5632	err = err ? : bpf_object__init_prog_names(obj);
5633	err = err ? : bpf_object__collect_reloc(obj);
5634	if (err)
5635		goto out;
5636	bpf_object__elf_finish(obj);
5637
5638	bpf_object__for_each_program(prog, obj) {
5639		prog->sec_def = find_sec_def(prog->section_name);
5640		if (!prog->sec_def)
5641			/* couldn't guess, but user might manually specify */
5642			continue;
5643
5644		bpf_program__set_type(prog, prog->sec_def->prog_type);
5645		bpf_program__set_expected_attach_type(prog,
5646				prog->sec_def->expected_attach_type);
5647
5648		if (prog->sec_def->prog_type == BPF_PROG_TYPE_TRACING ||
5649		    prog->sec_def->prog_type == BPF_PROG_TYPE_EXT)
5650			prog->attach_prog_fd = OPTS_GET(opts, attach_prog_fd, 0);
5651	}
5652
5653	return obj;
5654out:
5655	bpf_object__close(obj);
5656	return ERR_PTR(err);
5657}
5658
5659static struct bpf_object *
5660__bpf_object__open_xattr(struct bpf_object_open_attr *attr, int flags)
5661{
5662	DECLARE_LIBBPF_OPTS(bpf_object_open_opts, opts,
5663		.relaxed_maps = flags & MAPS_RELAX_COMPAT,
5664	);
5665
5666	/* param validation */
5667	if (!attr->file)
5668		return NULL;
5669
5670	pr_debug("loading %s\n", attr->file);
5671	return __bpf_object__open(attr->file, NULL, 0, &opts);
5672}
5673
5674struct bpf_object *bpf_object__open_xattr(struct bpf_object_open_attr *attr)
5675{
5676	return __bpf_object__open_xattr(attr, 0);
5677}
5678
5679struct bpf_object *bpf_object__open(const char *path)
5680{
5681	struct bpf_object_open_attr attr = {
5682		.file		= path,
5683		.prog_type	= BPF_PROG_TYPE_UNSPEC,
5684	};
5685
5686	return bpf_object__open_xattr(&attr);
5687}
5688
5689struct bpf_object *
5690bpf_object__open_file(const char *path, const struct bpf_object_open_opts *opts)
5691{
5692	if (!path)
5693		return ERR_PTR(-EINVAL);
5694
5695	pr_debug("loading %s\n", path);
5696
5697	return __bpf_object__open(path, NULL, 0, opts);
5698}
5699
5700struct bpf_object *
5701bpf_object__open_mem(const void *obj_buf, size_t obj_buf_sz,
5702		     const struct bpf_object_open_opts *opts)
5703{
5704	if (!obj_buf || obj_buf_sz == 0)
5705		return ERR_PTR(-EINVAL);
5706
5707	return __bpf_object__open(NULL, obj_buf, obj_buf_sz, opts);
5708}
5709
5710struct bpf_object *
5711bpf_object__open_buffer(const void *obj_buf, size_t obj_buf_sz,
5712			const char *name)
5713{
5714	DECLARE_LIBBPF_OPTS(bpf_object_open_opts, opts,
5715		.object_name = name,
5716		/* wrong default, but backwards-compatible */
5717		.relaxed_maps = true,
5718	);
5719
5720	/* returning NULL is wrong, but backwards-compatible */
5721	if (!obj_buf || obj_buf_sz == 0)
5722		return NULL;
5723
5724	return bpf_object__open_mem(obj_buf, obj_buf_sz, &opts);
 
 
 
 
 
 
 
 
 
 
5725}
5726
5727int bpf_object__unload(struct bpf_object *obj)
5728{
5729	size_t i;
5730
5731	if (!obj)
5732		return -EINVAL;
5733
5734	for (i = 0; i < obj->nr_maps; i++) {
5735		zclose(obj->maps[i].fd);
5736		if (obj->maps[i].st_ops)
5737			zfree(&obj->maps[i].st_ops->kern_vdata);
5738	}
5739
5740	for (i = 0; i < obj->nr_programs; i++)
5741		bpf_program__unload(&obj->programs[i]);
5742
5743	return 0;
5744}
5745
5746static int bpf_object__sanitize_maps(struct bpf_object *obj)
5747{
5748	struct bpf_map *m;
5749
5750	bpf_object__for_each_map(m, obj) {
5751		if (!bpf_map__is_internal(m))
5752			continue;
5753		if (!obj->caps.global_data) {
5754			pr_warn("kernel doesn't support global data\n");
5755			return -ENOTSUP;
5756		}
5757		if (!obj->caps.array_mmap)
5758			m->def.map_flags ^= BPF_F_MMAPABLE;
5759	}
5760
5761	return 0;
5762}
5763
5764static int bpf_object__read_kallsyms_file(struct bpf_object *obj)
5765{
5766	char sym_type, sym_name[500];
5767	unsigned long long sym_addr;
5768	struct extern_desc *ext;
5769	int ret, err = 0;
5770	FILE *f;
5771
5772	f = fopen("/proc/kallsyms", "r");
5773	if (!f) {
5774		err = -errno;
5775		pr_warn("failed to open /proc/kallsyms: %d\n", err);
5776		return err;
5777	}
5778
5779	while (true) {
5780		ret = fscanf(f, "%llx %c %499s%*[^\n]\n",
5781			     &sym_addr, &sym_type, sym_name);
5782		if (ret == EOF && feof(f))
5783			break;
5784		if (ret != 3) {
5785			pr_warn("failed to read kallsyms entry: %d\n", ret);
5786			err = -EINVAL;
5787			goto out;
5788		}
5789
5790		ext = find_extern_by_name(obj, sym_name);
5791		if (!ext || ext->type != EXT_KSYM)
5792			continue;
5793
5794		if (ext->is_set && ext->ksym.addr != sym_addr) {
5795			pr_warn("extern (ksym) '%s' resolution is ambiguous: 0x%llx or 0x%llx\n",
5796				sym_name, ext->ksym.addr, sym_addr);
5797			err = -EINVAL;
5798			goto out;
5799		}
5800		if (!ext->is_set) {
5801			ext->is_set = true;
5802			ext->ksym.addr = sym_addr;
5803			pr_debug("extern (ksym) %s=0x%llx\n", sym_name, sym_addr);
5804		}
5805	}
5806
5807out:
5808	fclose(f);
5809	return err;
5810}
5811
5812static int bpf_object__resolve_externs(struct bpf_object *obj,
5813				       const char *extra_kconfig)
5814{
5815	bool need_config = false, need_kallsyms = false;
5816	struct extern_desc *ext;
5817	void *kcfg_data = NULL;
5818	int err, i;
5819
5820	if (obj->nr_extern == 0)
5821		return 0;
5822
5823	if (obj->kconfig_map_idx >= 0)
5824		kcfg_data = obj->maps[obj->kconfig_map_idx].mmaped;
5825
5826	for (i = 0; i < obj->nr_extern; i++) {
5827		ext = &obj->externs[i];
5828
5829		if (ext->type == EXT_KCFG &&
5830		    strcmp(ext->name, "LINUX_KERNEL_VERSION") == 0) {
5831			void *ext_val = kcfg_data + ext->kcfg.data_off;
5832			__u32 kver = get_kernel_version();
5833
5834			if (!kver) {
5835				pr_warn("failed to get kernel version\n");
5836				return -EINVAL;
5837			}
5838			err = set_kcfg_value_num(ext, ext_val, kver);
5839			if (err)
5840				return err;
5841			pr_debug("extern (kcfg) %s=0x%x\n", ext->name, kver);
5842		} else if (ext->type == EXT_KCFG &&
5843			   strncmp(ext->name, "CONFIG_", 7) == 0) {
5844			need_config = true;
5845		} else if (ext->type == EXT_KSYM) {
5846			need_kallsyms = true;
5847		} else {
5848			pr_warn("unrecognized extern '%s'\n", ext->name);
5849			return -EINVAL;
5850		}
5851	}
5852	if (need_config && extra_kconfig) {
5853		err = bpf_object__read_kconfig_mem(obj, extra_kconfig, kcfg_data);
5854		if (err)
5855			return -EINVAL;
5856		need_config = false;
5857		for (i = 0; i < obj->nr_extern; i++) {
5858			ext = &obj->externs[i];
5859			if (ext->type == EXT_KCFG && !ext->is_set) {
5860				need_config = true;
5861				break;
5862			}
5863		}
5864	}
5865	if (need_config) {
5866		err = bpf_object__read_kconfig_file(obj, kcfg_data);
5867		if (err)
5868			return -EINVAL;
5869	}
5870	if (need_kallsyms) {
5871		err = bpf_object__read_kallsyms_file(obj);
5872		if (err)
5873			return -EINVAL;
5874	}
5875	for (i = 0; i < obj->nr_extern; i++) {
5876		ext = &obj->externs[i];
5877
5878		if (!ext->is_set && !ext->is_weak) {
5879			pr_warn("extern %s (strong) not resolved\n", ext->name);
5880			return -ESRCH;
5881		} else if (!ext->is_set) {
5882			pr_debug("extern %s (weak) not resolved, defaulting to zero\n",
5883				 ext->name);
5884		}
5885	}
5886
5887	return 0;
5888}
5889
5890int bpf_object__load_xattr(struct bpf_object_load_attr *attr)
5891{
5892	struct bpf_object *obj;
5893	int err, i;
5894
5895	if (!attr)
5896		return -EINVAL;
5897	obj = attr->obj;
5898	if (!obj)
5899		return -EINVAL;
5900
5901	if (obj->loaded) {
5902		pr_warn("object '%s': load can't be attempted twice\n", obj->name);
5903		return -EINVAL;
5904	}
5905
5906	err = bpf_object__probe_loading(obj);
5907	err = err ? : bpf_object__probe_caps(obj);
5908	err = err ? : bpf_object__resolve_externs(obj, obj->kconfig);
5909	err = err ? : bpf_object__sanitize_and_load_btf(obj);
5910	err = err ? : bpf_object__sanitize_maps(obj);
5911	err = err ? : bpf_object__load_vmlinux_btf(obj);
5912	err = err ? : bpf_object__init_kern_struct_ops_maps(obj);
5913	err = err ? : bpf_object__create_maps(obj);
5914	err = err ? : bpf_object__relocate(obj, attr->target_btf_path);
5915	err = err ? : bpf_object__load_progs(obj, attr->log_level);
5916
5917	btf__free(obj->btf_vmlinux);
5918	obj->btf_vmlinux = NULL;
5919
5920	obj->loaded = true; /* doesn't matter if successfully or not */
5921
5922	if (err)
5923		goto out;
5924
5925	return 0;
5926out:
5927	/* unpin any maps that were auto-pinned during load */
5928	for (i = 0; i < obj->nr_maps; i++)
5929		if (obj->maps[i].pinned && !obj->maps[i].reused)
5930			bpf_map__unpin(&obj->maps[i], NULL);
5931
5932	bpf_object__unload(obj);
5933	pr_warn("failed to load object '%s'\n", obj->path);
5934	return err;
5935}
5936
5937int bpf_object__load(struct bpf_object *obj)
5938{
5939	struct bpf_object_load_attr attr = {
5940		.obj = obj,
5941	};
5942
5943	return bpf_object__load_xattr(&attr);
5944}
5945
5946static int make_parent_dir(const char *path)
5947{
5948	char *cp, errmsg[STRERR_BUFSIZE];
5949	char *dname, *dir;
5950	int err = 0;
5951
5952	dname = strdup(path);
5953	if (dname == NULL)
5954		return -ENOMEM;
5955
5956	dir = dirname(dname);
5957	if (mkdir(dir, 0700) && errno != EEXIST)
5958		err = -errno;
5959
5960	free(dname);
5961	if (err) {
5962		cp = libbpf_strerror_r(-err, errmsg, sizeof(errmsg));
5963		pr_warn("failed to mkdir %s: %s\n", path, cp);
5964	}
5965	return err;
5966}
5967
5968static int check_path(const char *path)
5969{
5970	char *cp, errmsg[STRERR_BUFSIZE];
5971	struct statfs st_fs;
5972	char *dname, *dir;
5973	int err = 0;
5974
5975	if (path == NULL)
5976		return -EINVAL;
5977
5978	dname = strdup(path);
5979	if (dname == NULL)
5980		return -ENOMEM;
5981
5982	dir = dirname(dname);
5983	if (statfs(dir, &st_fs)) {
5984		cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg));
5985		pr_warn("failed to statfs %s: %s\n", dir, cp);
5986		err = -errno;
5987	}
5988	free(dname);
5989
5990	if (!err && st_fs.f_type != BPF_FS_MAGIC) {
5991		pr_warn("specified path %s is not on BPF FS\n", path);
5992		err = -EINVAL;
5993	}
5994
5995	return err;
5996}
5997
5998int bpf_program__pin_instance(struct bpf_program *prog, const char *path,
5999			      int instance)
6000{
6001	char *cp, errmsg[STRERR_BUFSIZE];
6002	int err;
6003
6004	err = make_parent_dir(path);
6005	if (err)
6006		return err;
6007
6008	err = check_path(path);
6009	if (err)
6010		return err;
6011
6012	if (prog == NULL) {
6013		pr_warn("invalid program pointer\n");
6014		return -EINVAL;
6015	}
6016
6017	if (instance < 0 || instance >= prog->instances.nr) {
6018		pr_warn("invalid prog instance %d of prog %s (max %d)\n",
6019			instance, prog->section_name, prog->instances.nr);
6020		return -EINVAL;
6021	}
6022
6023	if (bpf_obj_pin(prog->instances.fds[instance], path)) {
6024		err = -errno;
6025		cp = libbpf_strerror_r(err, errmsg, sizeof(errmsg));
6026		pr_warn("failed to pin program: %s\n", cp);
6027		return err;
6028	}
6029	pr_debug("pinned program '%s'\n", path);
6030
6031	return 0;
6032}
6033
6034int bpf_program__unpin_instance(struct bpf_program *prog, const char *path,
6035				int instance)
6036{
6037	int err;
6038
6039	err = check_path(path);
6040	if (err)
6041		return err;
6042
6043	if (prog == NULL) {
6044		pr_warn("invalid program pointer\n");
6045		return -EINVAL;
6046	}
6047
6048	if (instance < 0 || instance >= prog->instances.nr) {
6049		pr_warn("invalid prog instance %d of prog %s (max %d)\n",
6050			instance, prog->section_name, prog->instances.nr);
6051		return -EINVAL;
6052	}
6053
6054	err = unlink(path);
6055	if (err != 0)
6056		return -errno;
6057	pr_debug("unpinned program '%s'\n", path);
6058
6059	return 0;
6060}
6061
6062int bpf_program__pin(struct bpf_program *prog, const char *path)
6063{
6064	int i, err;
6065
6066	err = make_parent_dir(path);
6067	if (err)
6068		return err;
6069
6070	err = check_path(path);
6071	if (err)
6072		return err;
6073
6074	if (prog == NULL) {
6075		pr_warn("invalid program pointer\n");
6076		return -EINVAL;
6077	}
6078
6079	if (prog->instances.nr <= 0) {
6080		pr_warn("no instances of prog %s to pin\n",
6081			   prog->section_name);
6082		return -EINVAL;
6083	}
6084
6085	if (prog->instances.nr == 1) {
6086		/* don't create subdirs when pinning single instance */
6087		return bpf_program__pin_instance(prog, path, 0);
6088	}
6089
6090	for (i = 0; i < prog->instances.nr; i++) {
6091		char buf[PATH_MAX];
6092		int len;
6093
6094		len = snprintf(buf, PATH_MAX, "%s/%d", path, i);
6095		if (len < 0) {
6096			err = -EINVAL;
6097			goto err_unpin;
6098		} else if (len >= PATH_MAX) {
6099			err = -ENAMETOOLONG;
6100			goto err_unpin;
6101		}
6102
6103		err = bpf_program__pin_instance(prog, buf, i);
6104		if (err)
6105			goto err_unpin;
6106	}
6107
6108	return 0;
6109
6110err_unpin:
6111	for (i = i - 1; i >= 0; i--) {
6112		char buf[PATH_MAX];
6113		int len;
6114
6115		len = snprintf(buf, PATH_MAX, "%s/%d", path, i);
6116		if (len < 0)
6117			continue;
6118		else if (len >= PATH_MAX)
6119			continue;
6120
6121		bpf_program__unpin_instance(prog, buf, i);
6122	}
6123
6124	rmdir(path);
6125
6126	return err;
6127}
6128
6129int bpf_program__unpin(struct bpf_program *prog, const char *path)
6130{
6131	int i, err;
6132
6133	err = check_path(path);
6134	if (err)
6135		return err;
6136
6137	if (prog == NULL) {
6138		pr_warn("invalid program pointer\n");
6139		return -EINVAL;
6140	}
6141
6142	if (prog->instances.nr <= 0) {
6143		pr_warn("no instances of prog %s to pin\n",
6144			   prog->section_name);
6145		return -EINVAL;
6146	}
6147
6148	if (prog->instances.nr == 1) {
6149		/* don't create subdirs when pinning single instance */
6150		return bpf_program__unpin_instance(prog, path, 0);
6151	}
6152
6153	for (i = 0; i < prog->instances.nr; i++) {
6154		char buf[PATH_MAX];
6155		int len;
6156
6157		len = snprintf(buf, PATH_MAX, "%s/%d", path, i);
6158		if (len < 0)
6159			return -EINVAL;
6160		else if (len >= PATH_MAX)
6161			return -ENAMETOOLONG;
6162
6163		err = bpf_program__unpin_instance(prog, buf, i);
6164		if (err)
6165			return err;
6166	}
6167
6168	err = rmdir(path);
6169	if (err)
6170		return -errno;
6171
6172	return 0;
6173}
6174
6175int bpf_map__pin(struct bpf_map *map, const char *path)
6176{
6177	char *cp, errmsg[STRERR_BUFSIZE];
6178	int err;
6179
6180	if (map == NULL) {
6181		pr_warn("invalid map pointer\n");
6182		return -EINVAL;
6183	}
6184
6185	if (map->pin_path) {
6186		if (path && strcmp(path, map->pin_path)) {
6187			pr_warn("map '%s' already has pin path '%s' different from '%s'\n",
6188				bpf_map__name(map), map->pin_path, path);
6189			return -EINVAL;
6190		} else if (map->pinned) {
6191			pr_debug("map '%s' already pinned at '%s'; not re-pinning\n",
6192				 bpf_map__name(map), map->pin_path);
6193			return 0;
6194		}
6195	} else {
6196		if (!path) {
6197			pr_warn("missing a path to pin map '%s' at\n",
6198				bpf_map__name(map));
6199			return -EINVAL;
6200		} else if (map->pinned) {
6201			pr_warn("map '%s' already pinned\n", bpf_map__name(map));
6202			return -EEXIST;
6203		}
6204
6205		map->pin_path = strdup(path);
6206		if (!map->pin_path) {
6207			err = -errno;
6208			goto out_err;
6209		}
6210	}
6211
6212	err = make_parent_dir(map->pin_path);
6213	if (err)
6214		return err;
6215
6216	err = check_path(map->pin_path);
6217	if (err)
6218		return err;
6219
6220	if (bpf_obj_pin(map->fd, map->pin_path)) {
6221		err = -errno;
6222		goto out_err;
6223	}
6224
6225	map->pinned = true;
6226	pr_debug("pinned map '%s'\n", map->pin_path);
6227
6228	return 0;
6229
6230out_err:
6231	cp = libbpf_strerror_r(-err, errmsg, sizeof(errmsg));
6232	pr_warn("failed to pin map: %s\n", cp);
6233	return err;
6234}
6235
6236int bpf_map__unpin(struct bpf_map *map, const char *path)
6237{
6238	int err;
6239
6240	if (map == NULL) {
6241		pr_warn("invalid map pointer\n");
6242		return -EINVAL;
6243	}
6244
6245	if (map->pin_path) {
6246		if (path && strcmp(path, map->pin_path)) {
6247			pr_warn("map '%s' already has pin path '%s' different from '%s'\n",
6248				bpf_map__name(map), map->pin_path, path);
6249			return -EINVAL;
6250		}
6251		path = map->pin_path;
6252	} else if (!path) {
6253		pr_warn("no path to unpin map '%s' from\n",
6254			bpf_map__name(map));
6255		return -EINVAL;
6256	}
6257
6258	err = check_path(path);
6259	if (err)
6260		return err;
6261
6262	err = unlink(path);
6263	if (err != 0)
6264		return -errno;
6265
6266	map->pinned = false;
6267	pr_debug("unpinned map '%s' from '%s'\n", bpf_map__name(map), path);
6268
6269	return 0;
6270}
6271
6272int bpf_map__set_pin_path(struct bpf_map *map, const char *path)
6273{
6274	char *new = NULL;
6275
6276	if (path) {
6277		new = strdup(path);
6278		if (!new)
6279			return -errno;
6280	}
6281
6282	free(map->pin_path);
6283	map->pin_path = new;
6284	return 0;
6285}
6286
6287const char *bpf_map__get_pin_path(const struct bpf_map *map)
6288{
6289	return map->pin_path;
6290}
6291
6292bool bpf_map__is_pinned(const struct bpf_map *map)
6293{
6294	return map->pinned;
6295}
6296
6297int bpf_object__pin_maps(struct bpf_object *obj, const char *path)
6298{
6299	struct bpf_map *map;
6300	int err;
6301
6302	if (!obj)
6303		return -ENOENT;
6304
6305	if (!obj->loaded) {
6306		pr_warn("object not yet loaded; load it first\n");
6307		return -ENOENT;
6308	}
6309
6310	bpf_object__for_each_map(map, obj) {
6311		char *pin_path = NULL;
6312		char buf[PATH_MAX];
6313
6314		if (path) {
6315			int len;
6316
6317			len = snprintf(buf, PATH_MAX, "%s/%s", path,
6318				       bpf_map__name(map));
6319			if (len < 0) {
6320				err = -EINVAL;
6321				goto err_unpin_maps;
6322			} else if (len >= PATH_MAX) {
6323				err = -ENAMETOOLONG;
6324				goto err_unpin_maps;
6325			}
6326			pin_path = buf;
6327		} else if (!map->pin_path) {
6328			continue;
6329		}
6330
6331		err = bpf_map__pin(map, pin_path);
6332		if (err)
6333			goto err_unpin_maps;
6334	}
6335
6336	return 0;
6337
6338err_unpin_maps:
6339	while ((map = bpf_map__prev(map, obj))) {
6340		if (!map->pin_path)
6341			continue;
6342
6343		bpf_map__unpin(map, NULL);
6344	}
6345
6346	return err;
6347}
6348
6349int bpf_object__unpin_maps(struct bpf_object *obj, const char *path)
6350{
6351	struct bpf_map *map;
6352	int err;
6353
6354	if (!obj)
6355		return -ENOENT;
6356
6357	bpf_object__for_each_map(map, obj) {
6358		char *pin_path = NULL;
6359		char buf[PATH_MAX];
6360
6361		if (path) {
6362			int len;
6363
6364			len = snprintf(buf, PATH_MAX, "%s/%s", path,
6365				       bpf_map__name(map));
6366			if (len < 0)
6367				return -EINVAL;
6368			else if (len >= PATH_MAX)
6369				return -ENAMETOOLONG;
6370			pin_path = buf;
6371		} else if (!map->pin_path) {
6372			continue;
6373		}
6374
6375		err = bpf_map__unpin(map, pin_path);
6376		if (err)
6377			return err;
6378	}
6379
6380	return 0;
6381}
6382
6383int bpf_object__pin_programs(struct bpf_object *obj, const char *path)
6384{
6385	struct bpf_program *prog;
6386	int err;
6387
6388	if (!obj)
6389		return -ENOENT;
6390
6391	if (!obj->loaded) {
6392		pr_warn("object not yet loaded; load it first\n");
6393		return -ENOENT;
6394	}
6395
6396	bpf_object__for_each_program(prog, obj) {
6397		char buf[PATH_MAX];
6398		int len;
6399
6400		len = snprintf(buf, PATH_MAX, "%s/%s", path,
6401			       prog->pin_name);
6402		if (len < 0) {
6403			err = -EINVAL;
6404			goto err_unpin_programs;
6405		} else if (len >= PATH_MAX) {
6406			err = -ENAMETOOLONG;
6407			goto err_unpin_programs;
6408		}
6409
6410		err = bpf_program__pin(prog, buf);
6411		if (err)
6412			goto err_unpin_programs;
6413	}
6414
6415	return 0;
6416
6417err_unpin_programs:
6418	while ((prog = bpf_program__prev(prog, obj))) {
6419		char buf[PATH_MAX];
6420		int len;
6421
6422		len = snprintf(buf, PATH_MAX, "%s/%s", path,
6423			       prog->pin_name);
6424		if (len < 0)
6425			continue;
6426		else if (len >= PATH_MAX)
6427			continue;
6428
6429		bpf_program__unpin(prog, buf);
6430	}
6431
6432	return err;
6433}
6434
6435int bpf_object__unpin_programs(struct bpf_object *obj, const char *path)
6436{
6437	struct bpf_program *prog;
6438	int err;
6439
6440	if (!obj)
6441		return -ENOENT;
6442
6443	bpf_object__for_each_program(prog, obj) {
6444		char buf[PATH_MAX];
6445		int len;
6446
6447		len = snprintf(buf, PATH_MAX, "%s/%s", path,
6448			       prog->pin_name);
6449		if (len < 0)
6450			return -EINVAL;
6451		else if (len >= PATH_MAX)
6452			return -ENAMETOOLONG;
6453
6454		err = bpf_program__unpin(prog, buf);
6455		if (err)
6456			return err;
6457	}
6458
6459	return 0;
6460}
6461
6462int bpf_object__pin(struct bpf_object *obj, const char *path)
6463{
6464	int err;
6465
6466	err = bpf_object__pin_maps(obj, path);
6467	if (err)
6468		return err;
6469
6470	err = bpf_object__pin_programs(obj, path);
6471	if (err) {
6472		bpf_object__unpin_maps(obj, path);
6473		return err;
6474	}
6475
6476	return 0;
6477}
6478
6479static void bpf_map__destroy(struct bpf_map *map)
6480{
6481	if (map->clear_priv)
6482		map->clear_priv(map, map->priv);
6483	map->priv = NULL;
6484	map->clear_priv = NULL;
6485
6486	if (map->inner_map) {
6487		bpf_map__destroy(map->inner_map);
6488		zfree(&map->inner_map);
6489	}
6490
6491	zfree(&map->init_slots);
6492	map->init_slots_sz = 0;
6493
6494	if (map->mmaped) {
6495		munmap(map->mmaped, bpf_map_mmap_sz(map));
6496		map->mmaped = NULL;
6497	}
6498
6499	if (map->st_ops) {
6500		zfree(&map->st_ops->data);
6501		zfree(&map->st_ops->progs);
6502		zfree(&map->st_ops->kern_func_off);
6503		zfree(&map->st_ops);
6504	}
6505
6506	zfree(&map->name);
6507	zfree(&map->pin_path);
6508
6509	if (map->fd >= 0)
6510		zclose(map->fd);
6511}
6512
6513void bpf_object__close(struct bpf_object *obj)
6514{
6515	size_t i;
6516
6517	if (IS_ERR_OR_NULL(obj))
6518		return;
6519
6520	if (obj->clear_priv)
6521		obj->clear_priv(obj, obj->priv);
6522
6523	bpf_object__elf_finish(obj);
6524	bpf_object__unload(obj);
6525	btf__free(obj->btf);
6526	btf_ext__free(obj->btf_ext);
6527
6528	for (i = 0; i < obj->nr_maps; i++)
6529		bpf_map__destroy(&obj->maps[i]);
6530
6531	zfree(&obj->kconfig);
6532	zfree(&obj->externs);
6533	obj->nr_extern = 0;
6534
 
 
 
 
 
 
 
 
6535	zfree(&obj->maps);
6536	obj->nr_maps = 0;
6537
6538	if (obj->programs && obj->nr_programs) {
6539		for (i = 0; i < obj->nr_programs; i++)
6540			bpf_program__exit(&obj->programs[i]);
6541	}
6542	zfree(&obj->programs);
6543
6544	list_del(&obj->list);
6545	free(obj);
6546}
6547
6548struct bpf_object *
6549bpf_object__next(struct bpf_object *prev)
6550{
6551	struct bpf_object *next;
6552
6553	if (!prev)
6554		next = list_first_entry(&bpf_objects_list,
6555					struct bpf_object,
6556					list);
6557	else
6558		next = list_next_entry(prev, list);
6559
6560	/* Empty list is noticed here so don't need checking on entry. */
6561	if (&next->list == &bpf_objects_list)
6562		return NULL;
6563
6564	return next;
6565}
6566
6567const char *bpf_object__name(const struct bpf_object *obj)
6568{
6569	return obj ? obj->name : ERR_PTR(-EINVAL);
6570}
6571
6572unsigned int bpf_object__kversion(const struct bpf_object *obj)
6573{
6574	return obj ? obj->kern_version : 0;
6575}
6576
6577struct btf *bpf_object__btf(const struct bpf_object *obj)
6578{
6579	return obj ? obj->btf : NULL;
6580}
6581
6582int bpf_object__btf_fd(const struct bpf_object *obj)
6583{
6584	return obj->btf ? btf__fd(obj->btf) : -1;
6585}
6586
6587int bpf_object__set_priv(struct bpf_object *obj, void *priv,
6588			 bpf_object_clear_priv_t clear_priv)
6589{
6590	if (obj->priv && obj->clear_priv)
6591		obj->clear_priv(obj, obj->priv);
6592
6593	obj->priv = priv;
6594	obj->clear_priv = clear_priv;
6595	return 0;
6596}
6597
6598void *bpf_object__priv(const struct bpf_object *obj)
6599{
6600	return obj ? obj->priv : ERR_PTR(-EINVAL);
6601}
6602
6603static struct bpf_program *
6604__bpf_program__iter(const struct bpf_program *p, const struct bpf_object *obj,
6605		    bool forward)
6606{
6607	size_t nr_programs = obj->nr_programs;
6608	ssize_t idx;
6609
6610	if (!nr_programs)
6611		return NULL;
 
 
 
6612
6613	if (!p)
6614		/* Iter from the beginning */
6615		return forward ? &obj->programs[0] :
6616			&obj->programs[nr_programs - 1];
6617
6618	if (p->obj != obj) {
6619		pr_warn("error: program handler doesn't match object\n");
6620		return NULL;
6621	}
6622
6623	idx = (p - obj->programs) + (forward ? 1 : -1);
6624	if (idx >= obj->nr_programs || idx < 0)
6625		return NULL;
6626	return &obj->programs[idx];
6627}
6628
6629struct bpf_program *
6630bpf_program__next(struct bpf_program *prev, const struct bpf_object *obj)
6631{
6632	struct bpf_program *prog = prev;
6633
6634	do {
6635		prog = __bpf_program__iter(prog, obj, true);
6636	} while (prog && bpf_program__is_function_storage(prog, obj));
6637
6638	return prog;
6639}
6640
6641struct bpf_program *
6642bpf_program__prev(struct bpf_program *next, const struct bpf_object *obj)
6643{
6644	struct bpf_program *prog = next;
6645
6646	do {
6647		prog = __bpf_program__iter(prog, obj, false);
6648	} while (prog && bpf_program__is_function_storage(prog, obj));
6649
6650	return prog;
6651}
6652
6653int bpf_program__set_priv(struct bpf_program *prog, void *priv,
6654			  bpf_program_clear_priv_t clear_priv)
6655{
6656	if (prog->priv && prog->clear_priv)
6657		prog->clear_priv(prog, prog->priv);
6658
6659	prog->priv = priv;
6660	prog->clear_priv = clear_priv;
6661	return 0;
6662}
6663
6664void *bpf_program__priv(const struct bpf_program *prog)
6665{
6666	return prog ? prog->priv : ERR_PTR(-EINVAL);
6667}
6668
6669void bpf_program__set_ifindex(struct bpf_program *prog, __u32 ifindex)
6670{
6671	prog->prog_ifindex = ifindex;
6672}
6673
6674const char *bpf_program__name(const struct bpf_program *prog)
6675{
6676	return prog->name;
6677}
6678
6679const char *bpf_program__title(const struct bpf_program *prog, bool needs_copy)
6680{
6681	const char *title;
6682
6683	title = prog->section_name;
6684	if (needs_copy) {
6685		title = strdup(title);
6686		if (!title) {
6687			pr_warn("failed to strdup program title\n");
6688			return ERR_PTR(-ENOMEM);
6689		}
6690	}
6691
6692	return title;
6693}
6694
6695bool bpf_program__autoload(const struct bpf_program *prog)
6696{
6697	return prog->load;
6698}
6699
6700int bpf_program__set_autoload(struct bpf_program *prog, bool autoload)
6701{
6702	if (prog->obj->loaded)
6703		return -EINVAL;
6704
6705	prog->load = autoload;
6706	return 0;
6707}
6708
6709int bpf_program__fd(const struct bpf_program *prog)
6710{
6711	return bpf_program__nth_fd(prog, 0);
6712}
6713
6714size_t bpf_program__size(const struct bpf_program *prog)
6715{
6716	return prog->insns_cnt * sizeof(struct bpf_insn);
6717}
6718
6719int bpf_program__set_prep(struct bpf_program *prog, int nr_instances,
6720			  bpf_program_prep_t prep)
6721{
6722	int *instances_fds;
6723
6724	if (nr_instances <= 0 || !prep)
6725		return -EINVAL;
6726
6727	if (prog->instances.nr > 0 || prog->instances.fds) {
6728		pr_warn("Can't set pre-processor after loading\n");
6729		return -EINVAL;
6730	}
6731
6732	instances_fds = malloc(sizeof(int) * nr_instances);
6733	if (!instances_fds) {
6734		pr_warn("alloc memory failed for fds\n");
6735		return -ENOMEM;
6736	}
6737
6738	/* fill all fd with -1 */
6739	memset(instances_fds, -1, sizeof(int) * nr_instances);
6740
6741	prog->instances.nr = nr_instances;
6742	prog->instances.fds = instances_fds;
6743	prog->preprocessor = prep;
6744	return 0;
6745}
6746
6747int bpf_program__nth_fd(const struct bpf_program *prog, int n)
6748{
6749	int fd;
6750
6751	if (!prog)
6752		return -EINVAL;
6753
6754	if (n >= prog->instances.nr || n < 0) {
6755		pr_warn("Can't get the %dth fd from program %s: only %d instances\n",
6756			n, prog->section_name, prog->instances.nr);
6757		return -EINVAL;
6758	}
6759
6760	fd = prog->instances.fds[n];
6761	if (fd < 0) {
6762		pr_warn("%dth instance of program '%s' is invalid\n",
6763			n, prog->section_name);
6764		return -ENOENT;
6765	}
6766
6767	return fd;
6768}
6769
6770enum bpf_prog_type bpf_program__get_type(struct bpf_program *prog)
6771{
6772	return prog->type;
6773}
6774
6775void bpf_program__set_type(struct bpf_program *prog, enum bpf_prog_type type)
6776{
6777	prog->type = type;
6778}
6779
6780static bool bpf_program__is_type(const struct bpf_program *prog,
6781				 enum bpf_prog_type type)
6782{
6783	return prog ? (prog->type == type) : false;
6784}
6785
6786#define BPF_PROG_TYPE_FNS(NAME, TYPE)				\
6787int bpf_program__set_##NAME(struct bpf_program *prog)		\
6788{								\
6789	if (!prog)						\
6790		return -EINVAL;					\
6791	bpf_program__set_type(prog, TYPE);			\
6792	return 0;						\
6793}								\
6794								\
6795bool bpf_program__is_##NAME(const struct bpf_program *prog)	\
6796{								\
6797	return bpf_program__is_type(prog, TYPE);		\
6798}								\
6799
6800BPF_PROG_TYPE_FNS(socket_filter, BPF_PROG_TYPE_SOCKET_FILTER);
6801BPF_PROG_TYPE_FNS(lsm, BPF_PROG_TYPE_LSM);
6802BPF_PROG_TYPE_FNS(kprobe, BPF_PROG_TYPE_KPROBE);
6803BPF_PROG_TYPE_FNS(sched_cls, BPF_PROG_TYPE_SCHED_CLS);
6804BPF_PROG_TYPE_FNS(sched_act, BPF_PROG_TYPE_SCHED_ACT);
6805BPF_PROG_TYPE_FNS(tracepoint, BPF_PROG_TYPE_TRACEPOINT);
6806BPF_PROG_TYPE_FNS(raw_tracepoint, BPF_PROG_TYPE_RAW_TRACEPOINT);
6807BPF_PROG_TYPE_FNS(xdp, BPF_PROG_TYPE_XDP);
6808BPF_PROG_TYPE_FNS(perf_event, BPF_PROG_TYPE_PERF_EVENT);
6809BPF_PROG_TYPE_FNS(tracing, BPF_PROG_TYPE_TRACING);
6810BPF_PROG_TYPE_FNS(struct_ops, BPF_PROG_TYPE_STRUCT_OPS);
6811BPF_PROG_TYPE_FNS(extension, BPF_PROG_TYPE_EXT);
6812BPF_PROG_TYPE_FNS(sk_lookup, BPF_PROG_TYPE_SK_LOOKUP);
6813
6814enum bpf_attach_type
6815bpf_program__get_expected_attach_type(struct bpf_program *prog)
6816{
6817	return prog->expected_attach_type;
6818}
6819
6820void bpf_program__set_expected_attach_type(struct bpf_program *prog,
6821					   enum bpf_attach_type type)
6822{
6823	prog->expected_attach_type = type;
6824}
6825
6826#define BPF_PROG_SEC_IMPL(string, ptype, eatype, eatype_optional,	    \
6827			  attachable, attach_btf)			    \
6828	{								    \
6829		.sec = string,						    \
6830		.len = sizeof(string) - 1,				    \
6831		.prog_type = ptype,					    \
6832		.expected_attach_type = eatype,				    \
6833		.is_exp_attach_type_optional = eatype_optional,		    \
6834		.is_attachable = attachable,				    \
6835		.is_attach_btf = attach_btf,				    \
6836	}
6837
6838/* Programs that can NOT be attached. */
6839#define BPF_PROG_SEC(string, ptype) BPF_PROG_SEC_IMPL(string, ptype, 0, 0, 0, 0)
6840
6841/* Programs that can be attached. */
6842#define BPF_APROG_SEC(string, ptype, atype) \
6843	BPF_PROG_SEC_IMPL(string, ptype, atype, true, 1, 0)
6844
6845/* Programs that must specify expected attach type at load time. */
6846#define BPF_EAPROG_SEC(string, ptype, eatype) \
6847	BPF_PROG_SEC_IMPL(string, ptype, eatype, false, 1, 0)
6848
6849/* Programs that use BTF to identify attach point */
6850#define BPF_PROG_BTF(string, ptype, eatype) \
6851	BPF_PROG_SEC_IMPL(string, ptype, eatype, false, 0, 1)
6852
6853/* Programs that can be attached but attach type can't be identified by section
6854 * name. Kept for backward compatibility.
6855 */
6856#define BPF_APROG_COMPAT(string, ptype) BPF_PROG_SEC(string, ptype)
6857
6858#define SEC_DEF(sec_pfx, ptype, ...) {					    \
6859	.sec = sec_pfx,							    \
6860	.len = sizeof(sec_pfx) - 1,					    \
6861	.prog_type = BPF_PROG_TYPE_##ptype,				    \
6862	__VA_ARGS__							    \
6863}
6864
6865static struct bpf_link *attach_kprobe(const struct bpf_sec_def *sec,
6866				      struct bpf_program *prog);
6867static struct bpf_link *attach_tp(const struct bpf_sec_def *sec,
6868				  struct bpf_program *prog);
6869static struct bpf_link *attach_raw_tp(const struct bpf_sec_def *sec,
6870				      struct bpf_program *prog);
6871static struct bpf_link *attach_trace(const struct bpf_sec_def *sec,
6872				     struct bpf_program *prog);
6873static struct bpf_link *attach_lsm(const struct bpf_sec_def *sec,
6874				   struct bpf_program *prog);
6875static struct bpf_link *attach_iter(const struct bpf_sec_def *sec,
6876				    struct bpf_program *prog);
6877
6878static const struct bpf_sec_def section_defs[] = {
6879	BPF_PROG_SEC("socket",			BPF_PROG_TYPE_SOCKET_FILTER),
6880	BPF_PROG_SEC("sk_reuseport",		BPF_PROG_TYPE_SK_REUSEPORT),
6881	SEC_DEF("kprobe/", KPROBE,
6882		.attach_fn = attach_kprobe),
6883	BPF_PROG_SEC("uprobe/",			BPF_PROG_TYPE_KPROBE),
6884	SEC_DEF("kretprobe/", KPROBE,
6885		.attach_fn = attach_kprobe),
6886	BPF_PROG_SEC("uretprobe/",		BPF_PROG_TYPE_KPROBE),
6887	BPF_PROG_SEC("classifier",		BPF_PROG_TYPE_SCHED_CLS),
6888	BPF_PROG_SEC("action",			BPF_PROG_TYPE_SCHED_ACT),
6889	SEC_DEF("tracepoint/", TRACEPOINT,
6890		.attach_fn = attach_tp),
6891	SEC_DEF("tp/", TRACEPOINT,
6892		.attach_fn = attach_tp),
6893	SEC_DEF("raw_tracepoint/", RAW_TRACEPOINT,
6894		.attach_fn = attach_raw_tp),
6895	SEC_DEF("raw_tp/", RAW_TRACEPOINT,
6896		.attach_fn = attach_raw_tp),
6897	SEC_DEF("tp_btf/", TRACING,
6898		.expected_attach_type = BPF_TRACE_RAW_TP,
6899		.is_attach_btf = true,
6900		.attach_fn = attach_trace),
6901	SEC_DEF("fentry/", TRACING,
6902		.expected_attach_type = BPF_TRACE_FENTRY,
6903		.is_attach_btf = true,
6904		.attach_fn = attach_trace),
6905	SEC_DEF("fmod_ret/", TRACING,
6906		.expected_attach_type = BPF_MODIFY_RETURN,
6907		.is_attach_btf = true,
6908		.attach_fn = attach_trace),
6909	SEC_DEF("fexit/", TRACING,
6910		.expected_attach_type = BPF_TRACE_FEXIT,
6911		.is_attach_btf = true,
6912		.attach_fn = attach_trace),
6913	SEC_DEF("freplace/", EXT,
6914		.is_attach_btf = true,
6915		.attach_fn = attach_trace),
6916	SEC_DEF("lsm/", LSM,
6917		.is_attach_btf = true,
6918		.expected_attach_type = BPF_LSM_MAC,
6919		.attach_fn = attach_lsm),
6920	SEC_DEF("iter/", TRACING,
6921		.expected_attach_type = BPF_TRACE_ITER,
6922		.is_attach_btf = true,
6923		.attach_fn = attach_iter),
6924	BPF_EAPROG_SEC("xdp_devmap/",		BPF_PROG_TYPE_XDP,
6925						BPF_XDP_DEVMAP),
6926	BPF_EAPROG_SEC("xdp_cpumap/",		BPF_PROG_TYPE_XDP,
6927						BPF_XDP_CPUMAP),
6928	BPF_APROG_SEC("xdp",			BPF_PROG_TYPE_XDP,
6929						BPF_XDP),
6930	BPF_PROG_SEC("perf_event",		BPF_PROG_TYPE_PERF_EVENT),
6931	BPF_PROG_SEC("lwt_in",			BPF_PROG_TYPE_LWT_IN),
6932	BPF_PROG_SEC("lwt_out",			BPF_PROG_TYPE_LWT_OUT),
6933	BPF_PROG_SEC("lwt_xmit",		BPF_PROG_TYPE_LWT_XMIT),
6934	BPF_PROG_SEC("lwt_seg6local",		BPF_PROG_TYPE_LWT_SEG6LOCAL),
6935	BPF_APROG_SEC("cgroup_skb/ingress",	BPF_PROG_TYPE_CGROUP_SKB,
6936						BPF_CGROUP_INET_INGRESS),
6937	BPF_APROG_SEC("cgroup_skb/egress",	BPF_PROG_TYPE_CGROUP_SKB,
6938						BPF_CGROUP_INET_EGRESS),
6939	BPF_APROG_COMPAT("cgroup/skb",		BPF_PROG_TYPE_CGROUP_SKB),
6940	BPF_EAPROG_SEC("cgroup/sock_create",	BPF_PROG_TYPE_CGROUP_SOCK,
6941						BPF_CGROUP_INET_SOCK_CREATE),
6942	BPF_EAPROG_SEC("cgroup/sock_release",	BPF_PROG_TYPE_CGROUP_SOCK,
6943						BPF_CGROUP_INET_SOCK_RELEASE),
6944	BPF_APROG_SEC("cgroup/sock",		BPF_PROG_TYPE_CGROUP_SOCK,
6945						BPF_CGROUP_INET_SOCK_CREATE),
6946	BPF_EAPROG_SEC("cgroup/post_bind4",	BPF_PROG_TYPE_CGROUP_SOCK,
6947						BPF_CGROUP_INET4_POST_BIND),
6948	BPF_EAPROG_SEC("cgroup/post_bind6",	BPF_PROG_TYPE_CGROUP_SOCK,
6949						BPF_CGROUP_INET6_POST_BIND),
6950	BPF_APROG_SEC("cgroup/dev",		BPF_PROG_TYPE_CGROUP_DEVICE,
6951						BPF_CGROUP_DEVICE),
6952	BPF_APROG_SEC("sockops",		BPF_PROG_TYPE_SOCK_OPS,
6953						BPF_CGROUP_SOCK_OPS),
6954	BPF_APROG_SEC("sk_skb/stream_parser",	BPF_PROG_TYPE_SK_SKB,
6955						BPF_SK_SKB_STREAM_PARSER),
6956	BPF_APROG_SEC("sk_skb/stream_verdict",	BPF_PROG_TYPE_SK_SKB,
6957						BPF_SK_SKB_STREAM_VERDICT),
6958	BPF_APROG_COMPAT("sk_skb",		BPF_PROG_TYPE_SK_SKB),
6959	BPF_APROG_SEC("sk_msg",			BPF_PROG_TYPE_SK_MSG,
6960						BPF_SK_MSG_VERDICT),
6961	BPF_APROG_SEC("lirc_mode2",		BPF_PROG_TYPE_LIRC_MODE2,
6962						BPF_LIRC_MODE2),
6963	BPF_APROG_SEC("flow_dissector",		BPF_PROG_TYPE_FLOW_DISSECTOR,
6964						BPF_FLOW_DISSECTOR),
6965	BPF_EAPROG_SEC("cgroup/bind4",		BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
6966						BPF_CGROUP_INET4_BIND),
6967	BPF_EAPROG_SEC("cgroup/bind6",		BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
6968						BPF_CGROUP_INET6_BIND),
6969	BPF_EAPROG_SEC("cgroup/connect4",	BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
6970						BPF_CGROUP_INET4_CONNECT),
6971	BPF_EAPROG_SEC("cgroup/connect6",	BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
6972						BPF_CGROUP_INET6_CONNECT),
6973	BPF_EAPROG_SEC("cgroup/sendmsg4",	BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
6974						BPF_CGROUP_UDP4_SENDMSG),
6975	BPF_EAPROG_SEC("cgroup/sendmsg6",	BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
6976						BPF_CGROUP_UDP6_SENDMSG),
6977	BPF_EAPROG_SEC("cgroup/recvmsg4",	BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
6978						BPF_CGROUP_UDP4_RECVMSG),
6979	BPF_EAPROG_SEC("cgroup/recvmsg6",	BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
6980						BPF_CGROUP_UDP6_RECVMSG),
6981	BPF_EAPROG_SEC("cgroup/getpeername4",	BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
6982						BPF_CGROUP_INET4_GETPEERNAME),
6983	BPF_EAPROG_SEC("cgroup/getpeername6",	BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
6984						BPF_CGROUP_INET6_GETPEERNAME),
6985	BPF_EAPROG_SEC("cgroup/getsockname4",	BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
6986						BPF_CGROUP_INET4_GETSOCKNAME),
6987	BPF_EAPROG_SEC("cgroup/getsockname6",	BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
6988						BPF_CGROUP_INET6_GETSOCKNAME),
6989	BPF_EAPROG_SEC("cgroup/sysctl",		BPF_PROG_TYPE_CGROUP_SYSCTL,
6990						BPF_CGROUP_SYSCTL),
6991	BPF_EAPROG_SEC("cgroup/getsockopt",	BPF_PROG_TYPE_CGROUP_SOCKOPT,
6992						BPF_CGROUP_GETSOCKOPT),
6993	BPF_EAPROG_SEC("cgroup/setsockopt",	BPF_PROG_TYPE_CGROUP_SOCKOPT,
6994						BPF_CGROUP_SETSOCKOPT),
6995	BPF_PROG_SEC("struct_ops",		BPF_PROG_TYPE_STRUCT_OPS),
6996	BPF_EAPROG_SEC("sk_lookup/",		BPF_PROG_TYPE_SK_LOOKUP,
6997						BPF_SK_LOOKUP),
6998};
6999
7000#undef BPF_PROG_SEC_IMPL
7001#undef BPF_PROG_SEC
7002#undef BPF_APROG_SEC
7003#undef BPF_EAPROG_SEC
7004#undef BPF_APROG_COMPAT
7005#undef SEC_DEF
7006
7007#define MAX_TYPE_NAME_SIZE 32
7008
7009static const struct bpf_sec_def *find_sec_def(const char *sec_name)
7010{
7011	int i, n = ARRAY_SIZE(section_defs);
7012
7013	for (i = 0; i < n; i++) {
7014		if (strncmp(sec_name,
7015			    section_defs[i].sec, section_defs[i].len))
7016			continue;
7017		return &section_defs[i];
7018	}
7019	return NULL;
7020}
7021
7022static char *libbpf_get_type_names(bool attach_type)
7023{
7024	int i, len = ARRAY_SIZE(section_defs) * MAX_TYPE_NAME_SIZE;
7025	char *buf;
7026
7027	buf = malloc(len);
7028	if (!buf)
7029		return NULL;
7030
7031	buf[0] = '\0';
7032	/* Forge string buf with all available names */
7033	for (i = 0; i < ARRAY_SIZE(section_defs); i++) {
7034		if (attach_type && !section_defs[i].is_attachable)
7035			continue;
7036
7037		if (strlen(buf) + strlen(section_defs[i].sec) + 2 > len) {
7038			free(buf);
7039			return NULL;
7040		}
7041		strcat(buf, " ");
7042		strcat(buf, section_defs[i].sec);
7043	}
7044
7045	return buf;
7046}
7047
7048int libbpf_prog_type_by_name(const char *name, enum bpf_prog_type *prog_type,
7049			     enum bpf_attach_type *expected_attach_type)
7050{
7051	const struct bpf_sec_def *sec_def;
7052	char *type_names;
7053
7054	if (!name)
7055		return -EINVAL;
7056
7057	sec_def = find_sec_def(name);
7058	if (sec_def) {
7059		*prog_type = sec_def->prog_type;
7060		*expected_attach_type = sec_def->expected_attach_type;
7061		return 0;
7062	}
7063
7064	pr_debug("failed to guess program type from ELF section '%s'\n", name);
7065	type_names = libbpf_get_type_names(false);
7066	if (type_names != NULL) {
7067		pr_debug("supported section(type) names are:%s\n", type_names);
7068		free(type_names);
7069	}
7070
7071	return -ESRCH;
7072}
7073
7074static struct bpf_map *find_struct_ops_map_by_offset(struct bpf_object *obj,
7075						     size_t offset)
7076{
7077	struct bpf_map *map;
7078	size_t i;
7079
7080	for (i = 0; i < obj->nr_maps; i++) {
7081		map = &obj->maps[i];
7082		if (!bpf_map__is_struct_ops(map))
7083			continue;
7084		if (map->sec_offset <= offset &&
7085		    offset - map->sec_offset < map->def.value_size)
7086			return map;
7087	}
7088
7089	return NULL;
7090}
7091
7092/* Collect the reloc from ELF and populate the st_ops->progs[] */
7093static int bpf_object__collect_st_ops_relos(struct bpf_object *obj,
7094					    GElf_Shdr *shdr, Elf_Data *data)
7095{
7096	const struct btf_member *member;
7097	struct bpf_struct_ops *st_ops;
7098	struct bpf_program *prog;
7099	unsigned int shdr_idx;
7100	const struct btf *btf;
7101	struct bpf_map *map;
7102	Elf_Data *symbols;
7103	unsigned int moff;
7104	const char *name;
7105	__u32 member_idx;
7106	GElf_Sym sym;
7107	GElf_Rel rel;
7108	int i, nrels;
7109
7110	symbols = obj->efile.symbols;
7111	btf = obj->btf;
7112	nrels = shdr->sh_size / shdr->sh_entsize;
7113	for (i = 0; i < nrels; i++) {
7114		if (!gelf_getrel(data, i, &rel)) {
7115			pr_warn("struct_ops reloc: failed to get %d reloc\n", i);
7116			return -LIBBPF_ERRNO__FORMAT;
7117		}
7118
7119		if (!gelf_getsym(symbols, GELF_R_SYM(rel.r_info), &sym)) {
7120			pr_warn("struct_ops reloc: symbol %zx not found\n",
7121				(size_t)GELF_R_SYM(rel.r_info));
7122			return -LIBBPF_ERRNO__FORMAT;
7123		}
7124
7125		name = elf_strptr(obj->efile.elf, obj->efile.strtabidx,
7126				  sym.st_name) ? : "<?>";
7127		map = find_struct_ops_map_by_offset(obj, rel.r_offset);
7128		if (!map) {
7129			pr_warn("struct_ops reloc: cannot find map at rel.r_offset %zu\n",
7130				(size_t)rel.r_offset);
7131			return -EINVAL;
7132		}
7133
7134		moff = rel.r_offset - map->sec_offset;
7135		shdr_idx = sym.st_shndx;
7136		st_ops = map->st_ops;
7137		pr_debug("struct_ops reloc %s: for %lld value %lld shdr_idx %u rel.r_offset %zu map->sec_offset %zu name %d (\'%s\')\n",
7138			 map->name,
7139			 (long long)(rel.r_info >> 32),
7140			 (long long)sym.st_value,
7141			 shdr_idx, (size_t)rel.r_offset,
7142			 map->sec_offset, sym.st_name, name);
7143
7144		if (shdr_idx >= SHN_LORESERVE) {
7145			pr_warn("struct_ops reloc %s: rel.r_offset %zu shdr_idx %u unsupported non-static function\n",
7146				map->name, (size_t)rel.r_offset, shdr_idx);
7147			return -LIBBPF_ERRNO__RELOC;
7148		}
7149
7150		member = find_member_by_offset(st_ops->type, moff * 8);
7151		if (!member) {
7152			pr_warn("struct_ops reloc %s: cannot find member at moff %u\n",
7153				map->name, moff);
7154			return -EINVAL;
7155		}
7156		member_idx = member - btf_members(st_ops->type);
7157		name = btf__name_by_offset(btf, member->name_off);
7158
7159		if (!resolve_func_ptr(btf, member->type, NULL)) {
7160			pr_warn("struct_ops reloc %s: cannot relocate non func ptr %s\n",
7161				map->name, name);
7162			return -EINVAL;
7163		}
7164
7165		prog = bpf_object__find_prog_by_idx(obj, shdr_idx);
7166		if (!prog) {
7167			pr_warn("struct_ops reloc %s: cannot find prog at shdr_idx %u to relocate func ptr %s\n",
7168				map->name, shdr_idx, name);
7169			return -EINVAL;
7170		}
7171
7172		if (prog->type == BPF_PROG_TYPE_UNSPEC) {
7173			const struct bpf_sec_def *sec_def;
7174
7175			sec_def = find_sec_def(prog->section_name);
7176			if (sec_def &&
7177			    sec_def->prog_type != BPF_PROG_TYPE_STRUCT_OPS) {
7178				/* for pr_warn */
7179				prog->type = sec_def->prog_type;
7180				goto invalid_prog;
7181			}
7182
7183			prog->type = BPF_PROG_TYPE_STRUCT_OPS;
7184			prog->attach_btf_id = st_ops->type_id;
7185			prog->expected_attach_type = member_idx;
7186		} else if (prog->type != BPF_PROG_TYPE_STRUCT_OPS ||
7187			   prog->attach_btf_id != st_ops->type_id ||
7188			   prog->expected_attach_type != member_idx) {
7189			goto invalid_prog;
7190		}
7191		st_ops->progs[member_idx] = prog;
7192	}
7193
7194	return 0;
7195
7196invalid_prog:
7197	pr_warn("struct_ops reloc %s: cannot use prog %s in sec %s with type %u attach_btf_id %u expected_attach_type %u for func ptr %s\n",
7198		map->name, prog->name, prog->section_name, prog->type,
7199		prog->attach_btf_id, prog->expected_attach_type, name);
7200	return -EINVAL;
7201}
7202
7203#define BTF_TRACE_PREFIX "btf_trace_"
7204#define BTF_LSM_PREFIX "bpf_lsm_"
7205#define BTF_ITER_PREFIX "bpf_iter_"
7206#define BTF_MAX_NAME_SIZE 128
7207
7208static int find_btf_by_prefix_kind(const struct btf *btf, const char *prefix,
7209				   const char *name, __u32 kind)
7210{
7211	char btf_type_name[BTF_MAX_NAME_SIZE];
7212	int ret;
7213
7214	ret = snprintf(btf_type_name, sizeof(btf_type_name),
7215		       "%s%s", prefix, name);
7216	/* snprintf returns the number of characters written excluding the
7217	 * the terminating null. So, if >= BTF_MAX_NAME_SIZE are written, it
7218	 * indicates truncation.
7219	 */
7220	if (ret < 0 || ret >= sizeof(btf_type_name))
7221		return -ENAMETOOLONG;
7222	return btf__find_by_name_kind(btf, btf_type_name, kind);
7223}
7224
7225static inline int __find_vmlinux_btf_id(struct btf *btf, const char *name,
7226					enum bpf_attach_type attach_type)
7227{
7228	int err;
7229
7230	if (attach_type == BPF_TRACE_RAW_TP)
7231		err = find_btf_by_prefix_kind(btf, BTF_TRACE_PREFIX, name,
7232					      BTF_KIND_TYPEDEF);
7233	else if (attach_type == BPF_LSM_MAC)
7234		err = find_btf_by_prefix_kind(btf, BTF_LSM_PREFIX, name,
7235					      BTF_KIND_FUNC);
7236	else if (attach_type == BPF_TRACE_ITER)
7237		err = find_btf_by_prefix_kind(btf, BTF_ITER_PREFIX, name,
7238					      BTF_KIND_FUNC);
7239	else
7240		err = btf__find_by_name_kind(btf, name, BTF_KIND_FUNC);
7241
7242	if (err <= 0)
7243		pr_warn("%s is not found in vmlinux BTF\n", name);
7244
7245	return err;
7246}
7247
7248int libbpf_find_vmlinux_btf_id(const char *name,
7249			       enum bpf_attach_type attach_type)
7250{
7251	struct btf *btf;
7252	int err;
7253
7254	btf = libbpf_find_kernel_btf();
7255	if (IS_ERR(btf)) {
7256		pr_warn("vmlinux BTF is not found\n");
7257		return -EINVAL;
7258	}
7259
7260	err = __find_vmlinux_btf_id(btf, name, attach_type);
7261	btf__free(btf);
7262	return err;
7263}
7264
7265static int libbpf_find_prog_btf_id(const char *name, __u32 attach_prog_fd)
 
7266{
7267	struct bpf_prog_info_linear *info_linear;
7268	struct bpf_prog_info *info;
7269	struct btf *btf = NULL;
7270	int err = -EINVAL;
7271
7272	info_linear = bpf_program__get_prog_info_linear(attach_prog_fd, 0);
7273	if (IS_ERR_OR_NULL(info_linear)) {
7274		pr_warn("failed get_prog_info_linear for FD %d\n",
7275			attach_prog_fd);
7276		return -EINVAL;
7277	}
7278	info = &info_linear->info;
7279	if (!info->btf_id) {
7280		pr_warn("The target program doesn't have BTF\n");
7281		goto out;
7282	}
7283	if (btf__get_from_id(info->btf_id, &btf)) {
7284		pr_warn("Failed to get BTF of the program\n");
7285		goto out;
7286	}
7287	err = btf__find_by_name_kind(btf, name, BTF_KIND_FUNC);
7288	btf__free(btf);
7289	if (err <= 0) {
7290		pr_warn("%s is not found in prog's BTF\n", name);
7291		goto out;
7292	}
7293out:
7294	free(info_linear);
7295	return err;
7296}
7297
7298static int libbpf_find_attach_btf_id(struct bpf_program *prog)
7299{
7300	enum bpf_attach_type attach_type = prog->expected_attach_type;
7301	__u32 attach_prog_fd = prog->attach_prog_fd;
7302	const char *name = prog->section_name;
7303	int i, err;
7304
7305	if (!name)
7306		return -EINVAL;
7307
7308	for (i = 0; i < ARRAY_SIZE(section_defs); i++) {
7309		if (!section_defs[i].is_attach_btf)
7310			continue;
7311		if (strncmp(name, section_defs[i].sec, section_defs[i].len))
7312			continue;
7313		if (attach_prog_fd)
7314			err = libbpf_find_prog_btf_id(name + section_defs[i].len,
7315						      attach_prog_fd);
7316		else
7317			err = __find_vmlinux_btf_id(prog->obj->btf_vmlinux,
7318						    name + section_defs[i].len,
7319						    attach_type);
7320		return err;
7321	}
7322	pr_warn("failed to identify btf_id based on ELF section name '%s'\n", name);
7323	return -ESRCH;
7324}
7325
7326int libbpf_attach_type_by_name(const char *name,
7327			       enum bpf_attach_type *attach_type)
7328{
7329	char *type_names;
7330	int i;
7331
7332	if (!name)
7333		return -EINVAL;
7334
7335	for (i = 0; i < ARRAY_SIZE(section_defs); i++) {
7336		if (strncmp(name, section_defs[i].sec, section_defs[i].len))
7337			continue;
7338		if (!section_defs[i].is_attachable)
7339			return -EINVAL;
7340		*attach_type = section_defs[i].expected_attach_type;
7341		return 0;
7342	}
7343	pr_debug("failed to guess attach type based on ELF section name '%s'\n", name);
7344	type_names = libbpf_get_type_names(true);
7345	if (type_names != NULL) {
7346		pr_debug("attachable section(type) names are:%s\n", type_names);
7347		free(type_names);
7348	}
7349
7350	return -EINVAL;
7351}
7352
7353int bpf_map__fd(const struct bpf_map *map)
7354{
7355	return map ? map->fd : -EINVAL;
7356}
7357
7358const struct bpf_map_def *bpf_map__def(const struct bpf_map *map)
7359{
7360	return map ? &map->def : ERR_PTR(-EINVAL);
7361}
7362
7363const char *bpf_map__name(const struct bpf_map *map)
7364{
7365	return map ? map->name : NULL;
7366}
7367
7368enum bpf_map_type bpf_map__type(const struct bpf_map *map)
7369{
7370	return map->def.type;
7371}
7372
7373int bpf_map__set_type(struct bpf_map *map, enum bpf_map_type type)
7374{
7375	if (map->fd >= 0)
7376		return -EBUSY;
7377	map->def.type = type;
7378	return 0;
7379}
7380
7381__u32 bpf_map__map_flags(const struct bpf_map *map)
7382{
7383	return map->def.map_flags;
7384}
7385
7386int bpf_map__set_map_flags(struct bpf_map *map, __u32 flags)
7387{
7388	if (map->fd >= 0)
7389		return -EBUSY;
7390	map->def.map_flags = flags;
7391	return 0;
7392}
7393
7394__u32 bpf_map__numa_node(const struct bpf_map *map)
7395{
7396	return map->numa_node;
7397}
7398
7399int bpf_map__set_numa_node(struct bpf_map *map, __u32 numa_node)
7400{
7401	if (map->fd >= 0)
7402		return -EBUSY;
7403	map->numa_node = numa_node;
7404	return 0;
7405}
7406
7407__u32 bpf_map__key_size(const struct bpf_map *map)
7408{
7409	return map->def.key_size;
7410}
7411
7412int bpf_map__set_key_size(struct bpf_map *map, __u32 size)
7413{
7414	if (map->fd >= 0)
7415		return -EBUSY;
7416	map->def.key_size = size;
7417	return 0;
7418}
7419
7420__u32 bpf_map__value_size(const struct bpf_map *map)
7421{
7422	return map->def.value_size;
7423}
7424
7425int bpf_map__set_value_size(struct bpf_map *map, __u32 size)
7426{
7427	if (map->fd >= 0)
7428		return -EBUSY;
7429	map->def.value_size = size;
7430	return 0;
7431}
7432
7433__u32 bpf_map__btf_key_type_id(const struct bpf_map *map)
7434{
7435	return map ? map->btf_key_type_id : 0;
7436}
7437
7438__u32 bpf_map__btf_value_type_id(const struct bpf_map *map)
7439{
7440	return map ? map->btf_value_type_id : 0;
7441}
7442
7443int bpf_map__set_priv(struct bpf_map *map, void *priv,
7444		     bpf_map_clear_priv_t clear_priv)
7445{
7446	if (!map)
7447		return -EINVAL;
7448
7449	if (map->priv) {
7450		if (map->clear_priv)
7451			map->clear_priv(map, map->priv);
7452	}
7453
7454	map->priv = priv;
7455	map->clear_priv = clear_priv;
7456	return 0;
7457}
7458
7459void *bpf_map__priv(const struct bpf_map *map)
7460{
7461	return map ? map->priv : ERR_PTR(-EINVAL);
7462}
7463
7464int bpf_map__set_initial_value(struct bpf_map *map,
7465			       const void *data, size_t size)
7466{
7467	if (!map->mmaped || map->libbpf_type == LIBBPF_MAP_KCONFIG ||
7468	    size != map->def.value_size || map->fd >= 0)
7469		return -EINVAL;
7470
7471	memcpy(map->mmaped, data, size);
7472	return 0;
7473}
7474
7475bool bpf_map__is_offload_neutral(const struct bpf_map *map)
7476{
7477	return map->def.type == BPF_MAP_TYPE_PERF_EVENT_ARRAY;
7478}
7479
7480bool bpf_map__is_internal(const struct bpf_map *map)
7481{
7482	return map->libbpf_type != LIBBPF_MAP_UNSPEC;
7483}
7484
7485__u32 bpf_map__ifindex(const struct bpf_map *map)
7486{
7487	return map->map_ifindex;
7488}
7489
7490int bpf_map__set_ifindex(struct bpf_map *map, __u32 ifindex)
7491{
7492	if (map->fd >= 0)
7493		return -EBUSY;
7494	map->map_ifindex = ifindex;
7495	return 0;
7496}
7497
7498int bpf_map__set_inner_map_fd(struct bpf_map *map, int fd)
7499{
7500	if (!bpf_map_type__is_map_in_map(map->def.type)) {
7501		pr_warn("error: unsupported map type\n");
7502		return -EINVAL;
7503	}
7504	if (map->inner_map_fd != -1) {
7505		pr_warn("error: inner_map_fd already specified\n");
7506		return -EINVAL;
7507	}
7508	map->inner_map_fd = fd;
7509	return 0;
7510}
7511
7512static struct bpf_map *
7513__bpf_map__iter(const struct bpf_map *m, const struct bpf_object *obj, int i)
7514{
7515	ssize_t idx;
7516	struct bpf_map *s, *e;
7517
7518	if (!obj || !obj->maps)
7519		return NULL;
7520
7521	s = obj->maps;
7522	e = obj->maps + obj->nr_maps;
7523
7524	if ((m < s) || (m >= e)) {
7525		pr_warn("error in %s: map handler doesn't belong to object\n",
7526			 __func__);
 
 
 
7527		return NULL;
7528	}
7529
7530	idx = (m - obj->maps) + i;
7531	if (idx >= obj->nr_maps || idx < 0)
7532		return NULL;
7533	return &obj->maps[idx];
7534}
7535
7536struct bpf_map *
7537bpf_map__next(const struct bpf_map *prev, const struct bpf_object *obj)
7538{
7539	if (prev == NULL)
7540		return obj->maps;
7541
7542	return __bpf_map__iter(prev, obj, 1);
7543}
7544
7545struct bpf_map *
7546bpf_map__prev(const struct bpf_map *next, const struct bpf_object *obj)
7547{
7548	if (next == NULL) {
7549		if (!obj->nr_maps)
7550			return NULL;
7551		return obj->maps + obj->nr_maps - 1;
7552	}
7553
7554	return __bpf_map__iter(next, obj, -1);
7555}
7556
7557struct bpf_map *
7558bpf_object__find_map_by_name(const struct bpf_object *obj, const char *name)
7559{
7560	struct bpf_map *pos;
7561
7562	bpf_object__for_each_map(pos, obj) {
7563		if (pos->name && !strcmp(pos->name, name))
7564			return pos;
7565	}
7566	return NULL;
7567}
7568
7569int
7570bpf_object__find_map_fd_by_name(const struct bpf_object *obj, const char *name)
7571{
7572	return bpf_map__fd(bpf_object__find_map_by_name(obj, name));
7573}
7574
7575struct bpf_map *
7576bpf_object__find_map_by_offset(struct bpf_object *obj, size_t offset)
7577{
7578	return ERR_PTR(-ENOTSUP);
7579}
7580
7581long libbpf_get_error(const void *ptr)
7582{
7583	return PTR_ERR_OR_ZERO(ptr);
7584}
7585
7586int bpf_prog_load(const char *file, enum bpf_prog_type type,
7587		  struct bpf_object **pobj, int *prog_fd)
7588{
7589	struct bpf_prog_load_attr attr;
7590
7591	memset(&attr, 0, sizeof(struct bpf_prog_load_attr));
7592	attr.file = file;
7593	attr.prog_type = type;
7594	attr.expected_attach_type = 0;
7595
7596	return bpf_prog_load_xattr(&attr, pobj, prog_fd);
7597}
7598
7599int bpf_prog_load_xattr(const struct bpf_prog_load_attr *attr,
7600			struct bpf_object **pobj, int *prog_fd)
7601{
7602	struct bpf_object_open_attr open_attr = {};
7603	struct bpf_program *prog, *first_prog = NULL;
7604	struct bpf_object *obj;
7605	struct bpf_map *map;
7606	int err;
7607
7608	if (!attr)
7609		return -EINVAL;
7610	if (!attr->file)
7611		return -EINVAL;
7612
7613	open_attr.file = attr->file;
7614	open_attr.prog_type = attr->prog_type;
7615
7616	obj = bpf_object__open_xattr(&open_attr);
7617	if (IS_ERR_OR_NULL(obj))
7618		return -ENOENT;
7619
7620	bpf_object__for_each_program(prog, obj) {
7621		enum bpf_attach_type attach_type = attr->expected_attach_type;
7622		/*
7623		 * to preserve backwards compatibility, bpf_prog_load treats
7624		 * attr->prog_type, if specified, as an override to whatever
7625		 * bpf_object__open guessed
7626		 */
7627		if (attr->prog_type != BPF_PROG_TYPE_UNSPEC) {
7628			bpf_program__set_type(prog, attr->prog_type);
7629			bpf_program__set_expected_attach_type(prog,
7630							      attach_type);
7631		}
7632		if (bpf_program__get_type(prog) == BPF_PROG_TYPE_UNSPEC) {
7633			/*
7634			 * we haven't guessed from section name and user
7635			 * didn't provide a fallback type, too bad...
7636			 */
7637			bpf_object__close(obj);
7638			return -EINVAL;
7639		}
7640
7641		prog->prog_ifindex = attr->ifindex;
7642		prog->log_level = attr->log_level;
7643		prog->prog_flags = attr->prog_flags;
7644		if (!first_prog)
7645			first_prog = prog;
7646	}
7647
7648	bpf_object__for_each_map(map, obj) {
7649		if (!bpf_map__is_offload_neutral(map))
7650			map->map_ifindex = attr->ifindex;
7651	}
7652
7653	if (!first_prog) {
7654		pr_warn("object file doesn't contain bpf program\n");
7655		bpf_object__close(obj);
7656		return -ENOENT;
7657	}
7658
7659	err = bpf_object__load(obj);
7660	if (err) {
7661		bpf_object__close(obj);
7662		return err;
7663	}
7664
7665	*pobj = obj;
7666	*prog_fd = bpf_program__fd(first_prog);
7667	return 0;
7668}
7669
7670struct bpf_link {
7671	int (*detach)(struct bpf_link *link);
7672	int (*destroy)(struct bpf_link *link);
7673	char *pin_path;		/* NULL, if not pinned */
7674	int fd;			/* hook FD, -1 if not applicable */
7675	bool disconnected;
7676};
7677
7678/* Replace link's underlying BPF program with the new one */
7679int bpf_link__update_program(struct bpf_link *link, struct bpf_program *prog)
7680{
7681	return bpf_link_update(bpf_link__fd(link), bpf_program__fd(prog), NULL);
7682}
7683
7684/* Release "ownership" of underlying BPF resource (typically, BPF program
7685 * attached to some BPF hook, e.g., tracepoint, kprobe, etc). Disconnected
7686 * link, when destructed through bpf_link__destroy() call won't attempt to
7687 * detach/unregisted that BPF resource. This is useful in situations where,
7688 * say, attached BPF program has to outlive userspace program that attached it
7689 * in the system. Depending on type of BPF program, though, there might be
7690 * additional steps (like pinning BPF program in BPF FS) necessary to ensure
7691 * exit of userspace program doesn't trigger automatic detachment and clean up
7692 * inside the kernel.
7693 */
7694void bpf_link__disconnect(struct bpf_link *link)
7695{
7696	link->disconnected = true;
7697}
7698
7699int bpf_link__destroy(struct bpf_link *link)
7700{
7701	int err = 0;
7702
7703	if (IS_ERR_OR_NULL(link))
7704		return 0;
7705
7706	if (!link->disconnected && link->detach)
7707		err = link->detach(link);
7708	if (link->destroy)
7709		link->destroy(link);
7710	if (link->pin_path)
7711		free(link->pin_path);
7712	free(link);
7713
7714	return err;
7715}
7716
7717int bpf_link__fd(const struct bpf_link *link)
7718{
7719	return link->fd;
7720}
7721
7722const char *bpf_link__pin_path(const struct bpf_link *link)
7723{
7724	return link->pin_path;
7725}
7726
7727static int bpf_link__detach_fd(struct bpf_link *link)
7728{
7729	return close(link->fd);
7730}
7731
7732struct bpf_link *bpf_link__open(const char *path)
7733{
7734	struct bpf_link *link;
7735	int fd;
7736
7737	fd = bpf_obj_get(path);
7738	if (fd < 0) {
7739		fd = -errno;
7740		pr_warn("failed to open link at %s: %d\n", path, fd);
7741		return ERR_PTR(fd);
7742	}
7743
7744	link = calloc(1, sizeof(*link));
7745	if (!link) {
7746		close(fd);
7747		return ERR_PTR(-ENOMEM);
7748	}
7749	link->detach = &bpf_link__detach_fd;
7750	link->fd = fd;
7751
7752	link->pin_path = strdup(path);
7753	if (!link->pin_path) {
7754		bpf_link__destroy(link);
7755		return ERR_PTR(-ENOMEM);
7756	}
7757
7758	return link;
7759}
7760
7761int bpf_link__detach(struct bpf_link *link)
7762{
7763	return bpf_link_detach(link->fd) ? -errno : 0;
7764}
7765
7766int bpf_link__pin(struct bpf_link *link, const char *path)
7767{
7768	int err;
7769
7770	if (link->pin_path)
7771		return -EBUSY;
7772	err = make_parent_dir(path);
7773	if (err)
7774		return err;
7775	err = check_path(path);
7776	if (err)
7777		return err;
7778
7779	link->pin_path = strdup(path);
7780	if (!link->pin_path)
7781		return -ENOMEM;
7782
7783	if (bpf_obj_pin(link->fd, link->pin_path)) {
7784		err = -errno;
7785		zfree(&link->pin_path);
7786		return err;
7787	}
7788
7789	pr_debug("link fd=%d: pinned at %s\n", link->fd, link->pin_path);
7790	return 0;
7791}
7792
7793int bpf_link__unpin(struct bpf_link *link)
7794{
7795	int err;
7796
7797	if (!link->pin_path)
7798		return -EINVAL;
7799
7800	err = unlink(link->pin_path);
7801	if (err != 0)
7802		return -errno;
7803
7804	pr_debug("link fd=%d: unpinned from %s\n", link->fd, link->pin_path);
7805	zfree(&link->pin_path);
7806	return 0;
7807}
7808
7809static int bpf_link__detach_perf_event(struct bpf_link *link)
7810{
7811	int err;
7812
7813	err = ioctl(link->fd, PERF_EVENT_IOC_DISABLE, 0);
7814	if (err)
7815		err = -errno;
7816
7817	close(link->fd);
7818	return err;
7819}
7820
7821struct bpf_link *bpf_program__attach_perf_event(struct bpf_program *prog,
7822						int pfd)
7823{
7824	char errmsg[STRERR_BUFSIZE];
7825	struct bpf_link *link;
7826	int prog_fd, err;
7827
7828	if (pfd < 0) {
7829		pr_warn("program '%s': invalid perf event FD %d\n",
7830			bpf_program__title(prog, false), pfd);
7831		return ERR_PTR(-EINVAL);
7832	}
7833	prog_fd = bpf_program__fd(prog);
7834	if (prog_fd < 0) {
7835		pr_warn("program '%s': can't attach BPF program w/o FD (did you load it?)\n",
7836			bpf_program__title(prog, false));
7837		return ERR_PTR(-EINVAL);
7838	}
7839
7840	link = calloc(1, sizeof(*link));
7841	if (!link)
7842		return ERR_PTR(-ENOMEM);
7843	link->detach = &bpf_link__detach_perf_event;
7844	link->fd = pfd;
7845
7846	if (ioctl(pfd, PERF_EVENT_IOC_SET_BPF, prog_fd) < 0) {
7847		err = -errno;
7848		free(link);
7849		pr_warn("program '%s': failed to attach to pfd %d: %s\n",
7850			bpf_program__title(prog, false), pfd,
7851			   libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
7852		if (err == -EPROTO)
7853			pr_warn("program '%s': try add PERF_SAMPLE_CALLCHAIN to or remove exclude_callchain_[kernel|user] from pfd %d\n",
7854				bpf_program__title(prog, false), pfd);
7855		return ERR_PTR(err);
7856	}
7857	if (ioctl(pfd, PERF_EVENT_IOC_ENABLE, 0) < 0) {
7858		err = -errno;
7859		free(link);
7860		pr_warn("program '%s': failed to enable pfd %d: %s\n",
7861			bpf_program__title(prog, false), pfd,
7862			   libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
7863		return ERR_PTR(err);
7864	}
7865	return link;
7866}
7867
7868/*
7869 * this function is expected to parse integer in the range of [0, 2^31-1] from
7870 * given file using scanf format string fmt. If actual parsed value is
7871 * negative, the result might be indistinguishable from error
7872 */
7873static int parse_uint_from_file(const char *file, const char *fmt)
7874{
7875	char buf[STRERR_BUFSIZE];
7876	int err, ret;
7877	FILE *f;
7878
7879	f = fopen(file, "r");
7880	if (!f) {
7881		err = -errno;
7882		pr_debug("failed to open '%s': %s\n", file,
7883			 libbpf_strerror_r(err, buf, sizeof(buf)));
7884		return err;
7885	}
7886	err = fscanf(f, fmt, &ret);
7887	if (err != 1) {
7888		err = err == EOF ? -EIO : -errno;
7889		pr_debug("failed to parse '%s': %s\n", file,
7890			libbpf_strerror_r(err, buf, sizeof(buf)));
7891		fclose(f);
7892		return err;
7893	}
7894	fclose(f);
7895	return ret;
7896}
7897
7898static int determine_kprobe_perf_type(void)
7899{
7900	const char *file = "/sys/bus/event_source/devices/kprobe/type";
7901
7902	return parse_uint_from_file(file, "%d\n");
7903}
7904
7905static int determine_uprobe_perf_type(void)
7906{
7907	const char *file = "/sys/bus/event_source/devices/uprobe/type";
7908
7909	return parse_uint_from_file(file, "%d\n");
7910}
7911
7912static int determine_kprobe_retprobe_bit(void)
7913{
7914	const char *file = "/sys/bus/event_source/devices/kprobe/format/retprobe";
7915
7916	return parse_uint_from_file(file, "config:%d\n");
7917}
7918
7919static int determine_uprobe_retprobe_bit(void)
7920{
7921	const char *file = "/sys/bus/event_source/devices/uprobe/format/retprobe";
7922
7923	return parse_uint_from_file(file, "config:%d\n");
7924}
7925
7926static int perf_event_open_probe(bool uprobe, bool retprobe, const char *name,
7927				 uint64_t offset, int pid)
7928{
7929	struct perf_event_attr attr = {};
7930	char errmsg[STRERR_BUFSIZE];
7931	int type, pfd, err;
7932
7933	type = uprobe ? determine_uprobe_perf_type()
7934		      : determine_kprobe_perf_type();
7935	if (type < 0) {
7936		pr_warn("failed to determine %s perf type: %s\n",
7937			uprobe ? "uprobe" : "kprobe",
7938			libbpf_strerror_r(type, errmsg, sizeof(errmsg)));
7939		return type;
7940	}
7941	if (retprobe) {
7942		int bit = uprobe ? determine_uprobe_retprobe_bit()
7943				 : determine_kprobe_retprobe_bit();
7944
7945		if (bit < 0) {
7946			pr_warn("failed to determine %s retprobe bit: %s\n",
7947				uprobe ? "uprobe" : "kprobe",
7948				libbpf_strerror_r(bit, errmsg, sizeof(errmsg)));
7949			return bit;
7950		}
7951		attr.config |= 1 << bit;
7952	}
7953	attr.size = sizeof(attr);
7954	attr.type = type;
7955	attr.config1 = ptr_to_u64(name); /* kprobe_func or uprobe_path */
7956	attr.config2 = offset;		 /* kprobe_addr or probe_offset */
7957
7958	/* pid filter is meaningful only for uprobes */
7959	pfd = syscall(__NR_perf_event_open, &attr,
7960		      pid < 0 ? -1 : pid /* pid */,
7961		      pid == -1 ? 0 : -1 /* cpu */,
7962		      -1 /* group_fd */, PERF_FLAG_FD_CLOEXEC);
7963	if (pfd < 0) {
7964		err = -errno;
7965		pr_warn("%s perf_event_open() failed: %s\n",
7966			uprobe ? "uprobe" : "kprobe",
7967			libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
7968		return err;
7969	}
7970	return pfd;
7971}
7972
7973struct bpf_link *bpf_program__attach_kprobe(struct bpf_program *prog,
7974					    bool retprobe,
7975					    const char *func_name)
7976{
7977	char errmsg[STRERR_BUFSIZE];
7978	struct bpf_link *link;
7979	int pfd, err;
7980
7981	pfd = perf_event_open_probe(false /* uprobe */, retprobe, func_name,
7982				    0 /* offset */, -1 /* pid */);
7983	if (pfd < 0) {
7984		pr_warn("program '%s': failed to create %s '%s' perf event: %s\n",
7985			bpf_program__title(prog, false),
7986			retprobe ? "kretprobe" : "kprobe", func_name,
7987			libbpf_strerror_r(pfd, errmsg, sizeof(errmsg)));
7988		return ERR_PTR(pfd);
7989	}
7990	link = bpf_program__attach_perf_event(prog, pfd);
7991	if (IS_ERR(link)) {
7992		close(pfd);
7993		err = PTR_ERR(link);
7994		pr_warn("program '%s': failed to attach to %s '%s': %s\n",
7995			bpf_program__title(prog, false),
7996			retprobe ? "kretprobe" : "kprobe", func_name,
7997			libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
7998		return link;
7999	}
8000	return link;
8001}
8002
8003static struct bpf_link *attach_kprobe(const struct bpf_sec_def *sec,
8004				      struct bpf_program *prog)
8005{
8006	const char *func_name;
8007	bool retprobe;
8008
8009	func_name = bpf_program__title(prog, false) + sec->len;
8010	retprobe = strcmp(sec->sec, "kretprobe/") == 0;
8011
8012	return bpf_program__attach_kprobe(prog, retprobe, func_name);
8013}
8014
8015struct bpf_link *bpf_program__attach_uprobe(struct bpf_program *prog,
8016					    bool retprobe, pid_t pid,
8017					    const char *binary_path,
8018					    size_t func_offset)
8019{
8020	char errmsg[STRERR_BUFSIZE];
8021	struct bpf_link *link;
8022	int pfd, err;
8023
8024	pfd = perf_event_open_probe(true /* uprobe */, retprobe,
8025				    binary_path, func_offset, pid);
8026	if (pfd < 0) {
8027		pr_warn("program '%s': failed to create %s '%s:0x%zx' perf event: %s\n",
8028			bpf_program__title(prog, false),
8029			retprobe ? "uretprobe" : "uprobe",
8030			binary_path, func_offset,
8031			libbpf_strerror_r(pfd, errmsg, sizeof(errmsg)));
8032		return ERR_PTR(pfd);
8033	}
8034	link = bpf_program__attach_perf_event(prog, pfd);
8035	if (IS_ERR(link)) {
8036		close(pfd);
8037		err = PTR_ERR(link);
8038		pr_warn("program '%s': failed to attach to %s '%s:0x%zx': %s\n",
8039			bpf_program__title(prog, false),
8040			retprobe ? "uretprobe" : "uprobe",
8041			binary_path, func_offset,
8042			libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
8043		return link;
8044	}
8045	return link;
8046}
8047
8048static int determine_tracepoint_id(const char *tp_category,
8049				   const char *tp_name)
8050{
8051	char file[PATH_MAX];
8052	int ret;
8053
8054	ret = snprintf(file, sizeof(file),
8055		       "/sys/kernel/debug/tracing/events/%s/%s/id",
8056		       tp_category, tp_name);
8057	if (ret < 0)
8058		return -errno;
8059	if (ret >= sizeof(file)) {
8060		pr_debug("tracepoint %s/%s path is too long\n",
8061			 tp_category, tp_name);
8062		return -E2BIG;
8063	}
8064	return parse_uint_from_file(file, "%d\n");
8065}
8066
8067static int perf_event_open_tracepoint(const char *tp_category,
8068				      const char *tp_name)
8069{
8070	struct perf_event_attr attr = {};
8071	char errmsg[STRERR_BUFSIZE];
8072	int tp_id, pfd, err;
8073
8074	tp_id = determine_tracepoint_id(tp_category, tp_name);
8075	if (tp_id < 0) {
8076		pr_warn("failed to determine tracepoint '%s/%s' perf event ID: %s\n",
8077			tp_category, tp_name,
8078			libbpf_strerror_r(tp_id, errmsg, sizeof(errmsg)));
8079		return tp_id;
8080	}
8081
8082	attr.type = PERF_TYPE_TRACEPOINT;
8083	attr.size = sizeof(attr);
8084	attr.config = tp_id;
8085
8086	pfd = syscall(__NR_perf_event_open, &attr, -1 /* pid */, 0 /* cpu */,
8087		      -1 /* group_fd */, PERF_FLAG_FD_CLOEXEC);
8088	if (pfd < 0) {
8089		err = -errno;
8090		pr_warn("tracepoint '%s/%s' perf_event_open() failed: %s\n",
8091			tp_category, tp_name,
8092			libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
8093		return err;
8094	}
8095	return pfd;
8096}
8097
8098struct bpf_link *bpf_program__attach_tracepoint(struct bpf_program *prog,
8099						const char *tp_category,
8100						const char *tp_name)
8101{
8102	char errmsg[STRERR_BUFSIZE];
8103	struct bpf_link *link;
8104	int pfd, err;
8105
8106	pfd = perf_event_open_tracepoint(tp_category, tp_name);
8107	if (pfd < 0) {
8108		pr_warn("program '%s': failed to create tracepoint '%s/%s' perf event: %s\n",
8109			bpf_program__title(prog, false),
8110			tp_category, tp_name,
8111			libbpf_strerror_r(pfd, errmsg, sizeof(errmsg)));
8112		return ERR_PTR(pfd);
8113	}
8114	link = bpf_program__attach_perf_event(prog, pfd);
8115	if (IS_ERR(link)) {
8116		close(pfd);
8117		err = PTR_ERR(link);
8118		pr_warn("program '%s': failed to attach to tracepoint '%s/%s': %s\n",
8119			bpf_program__title(prog, false),
8120			tp_category, tp_name,
8121			libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
8122		return link;
8123	}
8124	return link;
8125}
8126
8127static struct bpf_link *attach_tp(const struct bpf_sec_def *sec,
8128				  struct bpf_program *prog)
8129{
8130	char *sec_name, *tp_cat, *tp_name;
8131	struct bpf_link *link;
8132
8133	sec_name = strdup(bpf_program__title(prog, false));
8134	if (!sec_name)
8135		return ERR_PTR(-ENOMEM);
8136
8137	/* extract "tp/<category>/<name>" */
8138	tp_cat = sec_name + sec->len;
8139	tp_name = strchr(tp_cat, '/');
8140	if (!tp_name) {
8141		link = ERR_PTR(-EINVAL);
8142		goto out;
8143	}
8144	*tp_name = '\0';
8145	tp_name++;
8146
8147	link = bpf_program__attach_tracepoint(prog, tp_cat, tp_name);
8148out:
8149	free(sec_name);
8150	return link;
8151}
8152
8153struct bpf_link *bpf_program__attach_raw_tracepoint(struct bpf_program *prog,
8154						    const char *tp_name)
8155{
8156	char errmsg[STRERR_BUFSIZE];
8157	struct bpf_link *link;
8158	int prog_fd, pfd;
8159
8160	prog_fd = bpf_program__fd(prog);
8161	if (prog_fd < 0) {
8162		pr_warn("program '%s': can't attach before loaded\n",
8163			bpf_program__title(prog, false));
8164		return ERR_PTR(-EINVAL);
8165	}
8166
8167	link = calloc(1, sizeof(*link));
8168	if (!link)
8169		return ERR_PTR(-ENOMEM);
8170	link->detach = &bpf_link__detach_fd;
8171
8172	pfd = bpf_raw_tracepoint_open(tp_name, prog_fd);
8173	if (pfd < 0) {
8174		pfd = -errno;
8175		free(link);
8176		pr_warn("program '%s': failed to attach to raw tracepoint '%s': %s\n",
8177			bpf_program__title(prog, false), tp_name,
8178			libbpf_strerror_r(pfd, errmsg, sizeof(errmsg)));
8179		return ERR_PTR(pfd);
8180	}
8181	link->fd = pfd;
8182	return link;
8183}
8184
8185static struct bpf_link *attach_raw_tp(const struct bpf_sec_def *sec,
8186				      struct bpf_program *prog)
8187{
8188	const char *tp_name = bpf_program__title(prog, false) + sec->len;
8189
8190	return bpf_program__attach_raw_tracepoint(prog, tp_name);
8191}
8192
8193/* Common logic for all BPF program types that attach to a btf_id */
8194static struct bpf_link *bpf_program__attach_btf_id(struct bpf_program *prog)
8195{
8196	char errmsg[STRERR_BUFSIZE];
8197	struct bpf_link *link;
8198	int prog_fd, pfd;
8199
8200	prog_fd = bpf_program__fd(prog);
8201	if (prog_fd < 0) {
8202		pr_warn("program '%s': can't attach before loaded\n",
8203			bpf_program__title(prog, false));
8204		return ERR_PTR(-EINVAL);
8205	}
8206
8207	link = calloc(1, sizeof(*link));
8208	if (!link)
8209		return ERR_PTR(-ENOMEM);
8210	link->detach = &bpf_link__detach_fd;
8211
8212	pfd = bpf_raw_tracepoint_open(NULL, prog_fd);
8213	if (pfd < 0) {
8214		pfd = -errno;
8215		free(link);
8216		pr_warn("program '%s': failed to attach: %s\n",
8217			bpf_program__title(prog, false),
8218			libbpf_strerror_r(pfd, errmsg, sizeof(errmsg)));
8219		return ERR_PTR(pfd);
8220	}
8221	link->fd = pfd;
8222	return (struct bpf_link *)link;
8223}
8224
8225struct bpf_link *bpf_program__attach_trace(struct bpf_program *prog)
8226{
8227	return bpf_program__attach_btf_id(prog);
8228}
8229
8230struct bpf_link *bpf_program__attach_lsm(struct bpf_program *prog)
8231{
8232	return bpf_program__attach_btf_id(prog);
8233}
8234
8235static struct bpf_link *attach_trace(const struct bpf_sec_def *sec,
8236				     struct bpf_program *prog)
8237{
8238	return bpf_program__attach_trace(prog);
8239}
8240
8241static struct bpf_link *attach_lsm(const struct bpf_sec_def *sec,
8242				   struct bpf_program *prog)
8243{
8244	return bpf_program__attach_lsm(prog);
8245}
8246
8247static struct bpf_link *attach_iter(const struct bpf_sec_def *sec,
8248				    struct bpf_program *prog)
8249{
8250	return bpf_program__attach_iter(prog, NULL);
8251}
8252
8253static struct bpf_link *
8254bpf_program__attach_fd(struct bpf_program *prog, int target_fd,
8255		       const char *target_name)
8256{
8257	enum bpf_attach_type attach_type;
8258	char errmsg[STRERR_BUFSIZE];
8259	struct bpf_link *link;
8260	int prog_fd, link_fd;
8261
8262	prog_fd = bpf_program__fd(prog);
8263	if (prog_fd < 0) {
8264		pr_warn("program '%s': can't attach before loaded\n",
8265			bpf_program__title(prog, false));
8266		return ERR_PTR(-EINVAL);
8267	}
8268
8269	link = calloc(1, sizeof(*link));
8270	if (!link)
8271		return ERR_PTR(-ENOMEM);
8272	link->detach = &bpf_link__detach_fd;
8273
8274	attach_type = bpf_program__get_expected_attach_type(prog);
8275	link_fd = bpf_link_create(prog_fd, target_fd, attach_type, NULL);
8276	if (link_fd < 0) {
8277		link_fd = -errno;
8278		free(link);
8279		pr_warn("program '%s': failed to attach to %s: %s\n",
8280			bpf_program__title(prog, false), target_name,
8281			libbpf_strerror_r(link_fd, errmsg, sizeof(errmsg)));
8282		return ERR_PTR(link_fd);
8283	}
8284	link->fd = link_fd;
8285	return link;
8286}
8287
8288struct bpf_link *
8289bpf_program__attach_cgroup(struct bpf_program *prog, int cgroup_fd)
8290{
8291	return bpf_program__attach_fd(prog, cgroup_fd, "cgroup");
8292}
8293
8294struct bpf_link *
8295bpf_program__attach_netns(struct bpf_program *prog, int netns_fd)
8296{
8297	return bpf_program__attach_fd(prog, netns_fd, "netns");
8298}
8299
8300struct bpf_link *bpf_program__attach_xdp(struct bpf_program *prog, int ifindex)
8301{
8302	/* target_fd/target_ifindex use the same field in LINK_CREATE */
8303	return bpf_program__attach_fd(prog, ifindex, "xdp");
8304}
8305
8306struct bpf_link *
8307bpf_program__attach_iter(struct bpf_program *prog,
8308			 const struct bpf_iter_attach_opts *opts)
8309{
8310	DECLARE_LIBBPF_OPTS(bpf_link_create_opts, link_create_opts);
8311	char errmsg[STRERR_BUFSIZE];
8312	struct bpf_link *link;
8313	int prog_fd, link_fd;
8314	__u32 target_fd = 0;
8315
8316	if (!OPTS_VALID(opts, bpf_iter_attach_opts))
8317		return ERR_PTR(-EINVAL);
8318
8319	link_create_opts.iter_info = OPTS_GET(opts, link_info, (void *)0);
8320	link_create_opts.iter_info_len = OPTS_GET(opts, link_info_len, 0);
8321
8322	prog_fd = bpf_program__fd(prog);
8323	if (prog_fd < 0) {
8324		pr_warn("program '%s': can't attach before loaded\n",
8325			bpf_program__title(prog, false));
8326		return ERR_PTR(-EINVAL);
8327	}
8328
8329	link = calloc(1, sizeof(*link));
8330	if (!link)
8331		return ERR_PTR(-ENOMEM);
8332	link->detach = &bpf_link__detach_fd;
8333
8334	link_fd = bpf_link_create(prog_fd, target_fd, BPF_TRACE_ITER,
8335				  &link_create_opts);
8336	if (link_fd < 0) {
8337		link_fd = -errno;
8338		free(link);
8339		pr_warn("program '%s': failed to attach to iterator: %s\n",
8340			bpf_program__title(prog, false),
8341			libbpf_strerror_r(link_fd, errmsg, sizeof(errmsg)));
8342		return ERR_PTR(link_fd);
8343	}
8344	link->fd = link_fd;
8345	return link;
8346}
8347
8348struct bpf_link *bpf_program__attach(struct bpf_program *prog)
8349{
8350	const struct bpf_sec_def *sec_def;
8351
8352	sec_def = find_sec_def(bpf_program__title(prog, false));
8353	if (!sec_def || !sec_def->attach_fn)
8354		return ERR_PTR(-ESRCH);
8355
8356	return sec_def->attach_fn(sec_def, prog);
8357}
8358
8359static int bpf_link__detach_struct_ops(struct bpf_link *link)
8360{
8361	__u32 zero = 0;
8362
8363	if (bpf_map_delete_elem(link->fd, &zero))
8364		return -errno;
8365
8366	return 0;
8367}
8368
8369struct bpf_link *bpf_map__attach_struct_ops(struct bpf_map *map)
8370{
8371	struct bpf_struct_ops *st_ops;
8372	struct bpf_link *link;
8373	__u32 i, zero = 0;
8374	int err;
8375
8376	if (!bpf_map__is_struct_ops(map) || map->fd == -1)
8377		return ERR_PTR(-EINVAL);
8378
8379	link = calloc(1, sizeof(*link));
8380	if (!link)
8381		return ERR_PTR(-EINVAL);
8382
8383	st_ops = map->st_ops;
8384	for (i = 0; i < btf_vlen(st_ops->type); i++) {
8385		struct bpf_program *prog = st_ops->progs[i];
8386		void *kern_data;
8387		int prog_fd;
8388
8389		if (!prog)
8390			continue;
8391
8392		prog_fd = bpf_program__fd(prog);
8393		kern_data = st_ops->kern_vdata + st_ops->kern_func_off[i];
8394		*(unsigned long *)kern_data = prog_fd;
8395	}
8396
8397	err = bpf_map_update_elem(map->fd, &zero, st_ops->kern_vdata, 0);
8398	if (err) {
8399		err = -errno;
8400		free(link);
8401		return ERR_PTR(err);
8402	}
8403
8404	link->detach = bpf_link__detach_struct_ops;
8405	link->fd = map->fd;
8406
8407	return link;
8408}
8409
8410enum bpf_perf_event_ret
8411bpf_perf_event_read_simple(void *mmap_mem, size_t mmap_size, size_t page_size,
8412			   void **copy_mem, size_t *copy_size,
8413			   bpf_perf_event_print_t fn, void *private_data)
8414{
8415	struct perf_event_mmap_page *header = mmap_mem;
8416	__u64 data_head = ring_buffer_read_head(header);
8417	__u64 data_tail = header->data_tail;
8418	void *base = ((__u8 *)header) + page_size;
8419	int ret = LIBBPF_PERF_EVENT_CONT;
8420	struct perf_event_header *ehdr;
8421	size_t ehdr_size;
8422
8423	while (data_head != data_tail) {
8424		ehdr = base + (data_tail & (mmap_size - 1));
8425		ehdr_size = ehdr->size;
8426
8427		if (((void *)ehdr) + ehdr_size > base + mmap_size) {
8428			void *copy_start = ehdr;
8429			size_t len_first = base + mmap_size - copy_start;
8430			size_t len_secnd = ehdr_size - len_first;
8431
8432			if (*copy_size < ehdr_size) {
8433				free(*copy_mem);
8434				*copy_mem = malloc(ehdr_size);
8435				if (!*copy_mem) {
8436					*copy_size = 0;
8437					ret = LIBBPF_PERF_EVENT_ERROR;
8438					break;
8439				}
8440				*copy_size = ehdr_size;
8441			}
8442
8443			memcpy(*copy_mem, copy_start, len_first);
8444			memcpy(*copy_mem + len_first, base, len_secnd);
8445			ehdr = *copy_mem;
8446		}
8447
8448		ret = fn(ehdr, private_data);
8449		data_tail += ehdr_size;
8450		if (ret != LIBBPF_PERF_EVENT_CONT)
8451			break;
8452	}
8453
8454	ring_buffer_write_tail(header, data_tail);
8455	return ret;
8456}
8457
8458struct perf_buffer;
8459
8460struct perf_buffer_params {
8461	struct perf_event_attr *attr;
8462	/* if event_cb is specified, it takes precendence */
8463	perf_buffer_event_fn event_cb;
8464	/* sample_cb and lost_cb are higher-level common-case callbacks */
8465	perf_buffer_sample_fn sample_cb;
8466	perf_buffer_lost_fn lost_cb;
8467	void *ctx;
8468	int cpu_cnt;
8469	int *cpus;
8470	int *map_keys;
8471};
8472
8473struct perf_cpu_buf {
8474	struct perf_buffer *pb;
8475	void *base; /* mmap()'ed memory */
8476	void *buf; /* for reconstructing segmented data */
8477	size_t buf_size;
8478	int fd;
8479	int cpu;
8480	int map_key;
8481};
8482
8483struct perf_buffer {
8484	perf_buffer_event_fn event_cb;
8485	perf_buffer_sample_fn sample_cb;
8486	perf_buffer_lost_fn lost_cb;
8487	void *ctx; /* passed into callbacks */
8488
8489	size_t page_size;
8490	size_t mmap_size;
8491	struct perf_cpu_buf **cpu_bufs;
8492	struct epoll_event *events;
8493	int cpu_cnt; /* number of allocated CPU buffers */
8494	int epoll_fd; /* perf event FD */
8495	int map_fd; /* BPF_MAP_TYPE_PERF_EVENT_ARRAY BPF map FD */
8496};
8497
8498static void perf_buffer__free_cpu_buf(struct perf_buffer *pb,
8499				      struct perf_cpu_buf *cpu_buf)
8500{
8501	if (!cpu_buf)
8502		return;
8503	if (cpu_buf->base &&
8504	    munmap(cpu_buf->base, pb->mmap_size + pb->page_size))
8505		pr_warn("failed to munmap cpu_buf #%d\n", cpu_buf->cpu);
8506	if (cpu_buf->fd >= 0) {
8507		ioctl(cpu_buf->fd, PERF_EVENT_IOC_DISABLE, 0);
8508		close(cpu_buf->fd);
8509	}
8510	free(cpu_buf->buf);
8511	free(cpu_buf);
8512}
8513
8514void perf_buffer__free(struct perf_buffer *pb)
8515{
8516	int i;
8517
8518	if (IS_ERR_OR_NULL(pb))
8519		return;
8520	if (pb->cpu_bufs) {
8521		for (i = 0; i < pb->cpu_cnt; i++) {
8522			struct perf_cpu_buf *cpu_buf = pb->cpu_bufs[i];
8523
8524			if (!cpu_buf)
8525				continue;
8526
8527			bpf_map_delete_elem(pb->map_fd, &cpu_buf->map_key);
8528			perf_buffer__free_cpu_buf(pb, cpu_buf);
8529		}
8530		free(pb->cpu_bufs);
8531	}
8532	if (pb->epoll_fd >= 0)
8533		close(pb->epoll_fd);
8534	free(pb->events);
8535	free(pb);
8536}
8537
8538static struct perf_cpu_buf *
8539perf_buffer__open_cpu_buf(struct perf_buffer *pb, struct perf_event_attr *attr,
8540			  int cpu, int map_key)
8541{
8542	struct perf_cpu_buf *cpu_buf;
8543	char msg[STRERR_BUFSIZE];
8544	int err;
8545
8546	cpu_buf = calloc(1, sizeof(*cpu_buf));
8547	if (!cpu_buf)
8548		return ERR_PTR(-ENOMEM);
8549
8550	cpu_buf->pb = pb;
8551	cpu_buf->cpu = cpu;
8552	cpu_buf->map_key = map_key;
8553
8554	cpu_buf->fd = syscall(__NR_perf_event_open, attr, -1 /* pid */, cpu,
8555			      -1, PERF_FLAG_FD_CLOEXEC);
8556	if (cpu_buf->fd < 0) {
8557		err = -errno;
8558		pr_warn("failed to open perf buffer event on cpu #%d: %s\n",
8559			cpu, libbpf_strerror_r(err, msg, sizeof(msg)));
8560		goto error;
8561	}
8562
8563	cpu_buf->base = mmap(NULL, pb->mmap_size + pb->page_size,
8564			     PROT_READ | PROT_WRITE, MAP_SHARED,
8565			     cpu_buf->fd, 0);
8566	if (cpu_buf->base == MAP_FAILED) {
8567		cpu_buf->base = NULL;
8568		err = -errno;
8569		pr_warn("failed to mmap perf buffer on cpu #%d: %s\n",
8570			cpu, libbpf_strerror_r(err, msg, sizeof(msg)));
8571		goto error;
8572	}
8573
8574	if (ioctl(cpu_buf->fd, PERF_EVENT_IOC_ENABLE, 0) < 0) {
8575		err = -errno;
8576		pr_warn("failed to enable perf buffer event on cpu #%d: %s\n",
8577			cpu, libbpf_strerror_r(err, msg, sizeof(msg)));
8578		goto error;
8579	}
8580
8581	return cpu_buf;
8582
8583error:
8584	perf_buffer__free_cpu_buf(pb, cpu_buf);
8585	return (struct perf_cpu_buf *)ERR_PTR(err);
8586}
8587
8588static struct perf_buffer *__perf_buffer__new(int map_fd, size_t page_cnt,
8589					      struct perf_buffer_params *p);
8590
8591struct perf_buffer *perf_buffer__new(int map_fd, size_t page_cnt,
8592				     const struct perf_buffer_opts *opts)
8593{
8594	struct perf_buffer_params p = {};
8595	struct perf_event_attr attr = { 0, };
8596
8597	attr.config = PERF_COUNT_SW_BPF_OUTPUT,
8598	attr.type = PERF_TYPE_SOFTWARE;
8599	attr.sample_type = PERF_SAMPLE_RAW;
8600	attr.sample_period = 1;
8601	attr.wakeup_events = 1;
8602
8603	p.attr = &attr;
8604	p.sample_cb = opts ? opts->sample_cb : NULL;
8605	p.lost_cb = opts ? opts->lost_cb : NULL;
8606	p.ctx = opts ? opts->ctx : NULL;
8607
8608	return __perf_buffer__new(map_fd, page_cnt, &p);
8609}
8610
8611struct perf_buffer *
8612perf_buffer__new_raw(int map_fd, size_t page_cnt,
8613		     const struct perf_buffer_raw_opts *opts)
8614{
8615	struct perf_buffer_params p = {};
8616
8617	p.attr = opts->attr;
8618	p.event_cb = opts->event_cb;
8619	p.ctx = opts->ctx;
8620	p.cpu_cnt = opts->cpu_cnt;
8621	p.cpus = opts->cpus;
8622	p.map_keys = opts->map_keys;
8623
8624	return __perf_buffer__new(map_fd, page_cnt, &p);
8625}
8626
8627static struct perf_buffer *__perf_buffer__new(int map_fd, size_t page_cnt,
8628					      struct perf_buffer_params *p)
8629{
8630	const char *online_cpus_file = "/sys/devices/system/cpu/online";
8631	struct bpf_map_info map;
8632	char msg[STRERR_BUFSIZE];
8633	struct perf_buffer *pb;
8634	bool *online = NULL;
8635	__u32 map_info_len;
8636	int err, i, j, n;
8637
8638	if (page_cnt & (page_cnt - 1)) {
8639		pr_warn("page count should be power of two, but is %zu\n",
8640			page_cnt);
8641		return ERR_PTR(-EINVAL);
8642	}
8643
8644	/* best-effort sanity checks */
8645	memset(&map, 0, sizeof(map));
8646	map_info_len = sizeof(map);
8647	err = bpf_obj_get_info_by_fd(map_fd, &map, &map_info_len);
8648	if (err) {
8649		err = -errno;
8650		/* if BPF_OBJ_GET_INFO_BY_FD is supported, will return
8651		 * -EBADFD, -EFAULT, or -E2BIG on real error
8652		 */
8653		if (err != -EINVAL) {
8654			pr_warn("failed to get map info for map FD %d: %s\n",
8655				map_fd, libbpf_strerror_r(err, msg, sizeof(msg)));
8656			return ERR_PTR(err);
8657		}
8658		pr_debug("failed to get map info for FD %d; API not supported? Ignoring...\n",
8659			 map_fd);
8660	} else {
8661		if (map.type != BPF_MAP_TYPE_PERF_EVENT_ARRAY) {
8662			pr_warn("map '%s' should be BPF_MAP_TYPE_PERF_EVENT_ARRAY\n",
8663				map.name);
8664			return ERR_PTR(-EINVAL);
8665		}
8666	}
8667
8668	pb = calloc(1, sizeof(*pb));
8669	if (!pb)
8670		return ERR_PTR(-ENOMEM);
8671
8672	pb->event_cb = p->event_cb;
8673	pb->sample_cb = p->sample_cb;
8674	pb->lost_cb = p->lost_cb;
8675	pb->ctx = p->ctx;
8676
8677	pb->page_size = getpagesize();
8678	pb->mmap_size = pb->page_size * page_cnt;
8679	pb->map_fd = map_fd;
8680
8681	pb->epoll_fd = epoll_create1(EPOLL_CLOEXEC);
8682	if (pb->epoll_fd < 0) {
8683		err = -errno;
8684		pr_warn("failed to create epoll instance: %s\n",
8685			libbpf_strerror_r(err, msg, sizeof(msg)));
8686		goto error;
8687	}
8688
8689	if (p->cpu_cnt > 0) {
8690		pb->cpu_cnt = p->cpu_cnt;
8691	} else {
8692		pb->cpu_cnt = libbpf_num_possible_cpus();
8693		if (pb->cpu_cnt < 0) {
8694			err = pb->cpu_cnt;
8695			goto error;
8696		}
8697		if (map.max_entries && map.max_entries < pb->cpu_cnt)
8698			pb->cpu_cnt = map.max_entries;
8699	}
8700
8701	pb->events = calloc(pb->cpu_cnt, sizeof(*pb->events));
8702	if (!pb->events) {
8703		err = -ENOMEM;
8704		pr_warn("failed to allocate events: out of memory\n");
8705		goto error;
8706	}
8707	pb->cpu_bufs = calloc(pb->cpu_cnt, sizeof(*pb->cpu_bufs));
8708	if (!pb->cpu_bufs) {
8709		err = -ENOMEM;
8710		pr_warn("failed to allocate buffers: out of memory\n");
8711		goto error;
8712	}
8713
8714	err = parse_cpu_mask_file(online_cpus_file, &online, &n);
8715	if (err) {
8716		pr_warn("failed to get online CPU mask: %d\n", err);
8717		goto error;
8718	}
8719
8720	for (i = 0, j = 0; i < pb->cpu_cnt; i++) {
8721		struct perf_cpu_buf *cpu_buf;
8722		int cpu, map_key;
8723
8724		cpu = p->cpu_cnt > 0 ? p->cpus[i] : i;
8725		map_key = p->cpu_cnt > 0 ? p->map_keys[i] : i;
8726
8727		/* in case user didn't explicitly requested particular CPUs to
8728		 * be attached to, skip offline/not present CPUs
8729		 */
8730		if (p->cpu_cnt <= 0 && (cpu >= n || !online[cpu]))
8731			continue;
8732
8733		cpu_buf = perf_buffer__open_cpu_buf(pb, p->attr, cpu, map_key);
8734		if (IS_ERR(cpu_buf)) {
8735			err = PTR_ERR(cpu_buf);
8736			goto error;
8737		}
8738
8739		pb->cpu_bufs[j] = cpu_buf;
8740
8741		err = bpf_map_update_elem(pb->map_fd, &map_key,
8742					  &cpu_buf->fd, 0);
8743		if (err) {
8744			err = -errno;
8745			pr_warn("failed to set cpu #%d, key %d -> perf FD %d: %s\n",
8746				cpu, map_key, cpu_buf->fd,
8747				libbpf_strerror_r(err, msg, sizeof(msg)));
8748			goto error;
8749		}
8750
8751		pb->events[j].events = EPOLLIN;
8752		pb->events[j].data.ptr = cpu_buf;
8753		if (epoll_ctl(pb->epoll_fd, EPOLL_CTL_ADD, cpu_buf->fd,
8754			      &pb->events[j]) < 0) {
8755			err = -errno;
8756			pr_warn("failed to epoll_ctl cpu #%d perf FD %d: %s\n",
8757				cpu, cpu_buf->fd,
8758				libbpf_strerror_r(err, msg, sizeof(msg)));
8759			goto error;
8760		}
8761		j++;
8762	}
8763	pb->cpu_cnt = j;
8764	free(online);
8765
8766	return pb;
8767
8768error:
8769	free(online);
8770	if (pb)
8771		perf_buffer__free(pb);
8772	return ERR_PTR(err);
8773}
8774
8775struct perf_sample_raw {
8776	struct perf_event_header header;
8777	uint32_t size;
8778	char data[];
8779};
8780
8781struct perf_sample_lost {
8782	struct perf_event_header header;
8783	uint64_t id;
8784	uint64_t lost;
8785	uint64_t sample_id;
8786};
8787
8788static enum bpf_perf_event_ret
8789perf_buffer__process_record(struct perf_event_header *e, void *ctx)
8790{
8791	struct perf_cpu_buf *cpu_buf = ctx;
8792	struct perf_buffer *pb = cpu_buf->pb;
8793	void *data = e;
8794
8795	/* user wants full control over parsing perf event */
8796	if (pb->event_cb)
8797		return pb->event_cb(pb->ctx, cpu_buf->cpu, e);
8798
8799	switch (e->type) {
8800	case PERF_RECORD_SAMPLE: {
8801		struct perf_sample_raw *s = data;
8802
8803		if (pb->sample_cb)
8804			pb->sample_cb(pb->ctx, cpu_buf->cpu, s->data, s->size);
8805		break;
8806	}
8807	case PERF_RECORD_LOST: {
8808		struct perf_sample_lost *s = data;
8809
8810		if (pb->lost_cb)
8811			pb->lost_cb(pb->ctx, cpu_buf->cpu, s->lost);
8812		break;
8813	}
8814	default:
8815		pr_warn("unknown perf sample type %d\n", e->type);
8816		return LIBBPF_PERF_EVENT_ERROR;
8817	}
8818	return LIBBPF_PERF_EVENT_CONT;
8819}
8820
8821static int perf_buffer__process_records(struct perf_buffer *pb,
8822					struct perf_cpu_buf *cpu_buf)
8823{
8824	enum bpf_perf_event_ret ret;
8825
8826	ret = bpf_perf_event_read_simple(cpu_buf->base, pb->mmap_size,
8827					 pb->page_size, &cpu_buf->buf,
8828					 &cpu_buf->buf_size,
8829					 perf_buffer__process_record, cpu_buf);
8830	if (ret != LIBBPF_PERF_EVENT_CONT)
8831		return ret;
8832	return 0;
8833}
8834
8835int perf_buffer__poll(struct perf_buffer *pb, int timeout_ms)
8836{
8837	int i, cnt, err;
8838
8839	cnt = epoll_wait(pb->epoll_fd, pb->events, pb->cpu_cnt, timeout_ms);
8840	for (i = 0; i < cnt; i++) {
8841		struct perf_cpu_buf *cpu_buf = pb->events[i].data.ptr;
8842
8843		err = perf_buffer__process_records(pb, cpu_buf);
8844		if (err) {
8845			pr_warn("error while processing records: %d\n", err);
8846			return err;
8847		}
8848	}
8849	return cnt < 0 ? -errno : cnt;
8850}
8851
8852int perf_buffer__consume(struct perf_buffer *pb)
8853{
8854	int i, err;
8855
8856	for (i = 0; i < pb->cpu_cnt; i++) {
8857		struct perf_cpu_buf *cpu_buf = pb->cpu_bufs[i];
8858
8859		if (!cpu_buf)
8860			continue;
8861
8862		err = perf_buffer__process_records(pb, cpu_buf);
8863		if (err) {
8864			pr_warn("error while processing records: %d\n", err);
8865			return err;
8866		}
8867	}
8868	return 0;
8869}
8870
8871struct bpf_prog_info_array_desc {
8872	int	array_offset;	/* e.g. offset of jited_prog_insns */
8873	int	count_offset;	/* e.g. offset of jited_prog_len */
8874	int	size_offset;	/* > 0: offset of rec size,
8875				 * < 0: fix size of -size_offset
8876				 */
8877};
8878
8879static struct bpf_prog_info_array_desc bpf_prog_info_array_desc[] = {
8880	[BPF_PROG_INFO_JITED_INSNS] = {
8881		offsetof(struct bpf_prog_info, jited_prog_insns),
8882		offsetof(struct bpf_prog_info, jited_prog_len),
8883		-1,
8884	},
8885	[BPF_PROG_INFO_XLATED_INSNS] = {
8886		offsetof(struct bpf_prog_info, xlated_prog_insns),
8887		offsetof(struct bpf_prog_info, xlated_prog_len),
8888		-1,
8889	},
8890	[BPF_PROG_INFO_MAP_IDS] = {
8891		offsetof(struct bpf_prog_info, map_ids),
8892		offsetof(struct bpf_prog_info, nr_map_ids),
8893		-(int)sizeof(__u32),
8894	},
8895	[BPF_PROG_INFO_JITED_KSYMS] = {
8896		offsetof(struct bpf_prog_info, jited_ksyms),
8897		offsetof(struct bpf_prog_info, nr_jited_ksyms),
8898		-(int)sizeof(__u64),
8899	},
8900	[BPF_PROG_INFO_JITED_FUNC_LENS] = {
8901		offsetof(struct bpf_prog_info, jited_func_lens),
8902		offsetof(struct bpf_prog_info, nr_jited_func_lens),
8903		-(int)sizeof(__u32),
8904	},
8905	[BPF_PROG_INFO_FUNC_INFO] = {
8906		offsetof(struct bpf_prog_info, func_info),
8907		offsetof(struct bpf_prog_info, nr_func_info),
8908		offsetof(struct bpf_prog_info, func_info_rec_size),
8909	},
8910	[BPF_PROG_INFO_LINE_INFO] = {
8911		offsetof(struct bpf_prog_info, line_info),
8912		offsetof(struct bpf_prog_info, nr_line_info),
8913		offsetof(struct bpf_prog_info, line_info_rec_size),
8914	},
8915	[BPF_PROG_INFO_JITED_LINE_INFO] = {
8916		offsetof(struct bpf_prog_info, jited_line_info),
8917		offsetof(struct bpf_prog_info, nr_jited_line_info),
8918		offsetof(struct bpf_prog_info, jited_line_info_rec_size),
8919	},
8920	[BPF_PROG_INFO_PROG_TAGS] = {
8921		offsetof(struct bpf_prog_info, prog_tags),
8922		offsetof(struct bpf_prog_info, nr_prog_tags),
8923		-(int)sizeof(__u8) * BPF_TAG_SIZE,
8924	},
8925
8926};
8927
8928static __u32 bpf_prog_info_read_offset_u32(struct bpf_prog_info *info,
8929					   int offset)
8930{
8931	__u32 *array = (__u32 *)info;
8932
8933	if (offset >= 0)
8934		return array[offset / sizeof(__u32)];
8935	return -(int)offset;
8936}
8937
8938static __u64 bpf_prog_info_read_offset_u64(struct bpf_prog_info *info,
8939					   int offset)
8940{
8941	__u64 *array = (__u64 *)info;
8942
8943	if (offset >= 0)
8944		return array[offset / sizeof(__u64)];
8945	return -(int)offset;
8946}
8947
8948static void bpf_prog_info_set_offset_u32(struct bpf_prog_info *info, int offset,
8949					 __u32 val)
8950{
8951	__u32 *array = (__u32 *)info;
8952
8953	if (offset >= 0)
8954		array[offset / sizeof(__u32)] = val;
8955}
8956
8957static void bpf_prog_info_set_offset_u64(struct bpf_prog_info *info, int offset,
8958					 __u64 val)
8959{
8960	__u64 *array = (__u64 *)info;
8961
8962	if (offset >= 0)
8963		array[offset / sizeof(__u64)] = val;
8964}
8965
8966struct bpf_prog_info_linear *
8967bpf_program__get_prog_info_linear(int fd, __u64 arrays)
8968{
8969	struct bpf_prog_info_linear *info_linear;
8970	struct bpf_prog_info info = {};
8971	__u32 info_len = sizeof(info);
8972	__u32 data_len = 0;
8973	int i, err;
8974	void *ptr;
8975
8976	if (arrays >> BPF_PROG_INFO_LAST_ARRAY)
8977		return ERR_PTR(-EINVAL);
8978
8979	/* step 1: get array dimensions */
8980	err = bpf_obj_get_info_by_fd(fd, &info, &info_len);
8981	if (err) {
8982		pr_debug("can't get prog info: %s", strerror(errno));
8983		return ERR_PTR(-EFAULT);
8984	}
8985
8986	/* step 2: calculate total size of all arrays */
8987	for (i = BPF_PROG_INFO_FIRST_ARRAY; i < BPF_PROG_INFO_LAST_ARRAY; ++i) {
8988		bool include_array = (arrays & (1UL << i)) > 0;
8989		struct bpf_prog_info_array_desc *desc;
8990		__u32 count, size;
8991
8992		desc = bpf_prog_info_array_desc + i;
8993
8994		/* kernel is too old to support this field */
8995		if (info_len < desc->array_offset + sizeof(__u32) ||
8996		    info_len < desc->count_offset + sizeof(__u32) ||
8997		    (desc->size_offset > 0 && info_len < desc->size_offset))
8998			include_array = false;
8999
9000		if (!include_array) {
9001			arrays &= ~(1UL << i);	/* clear the bit */
9002			continue;
9003		}
9004
9005		count = bpf_prog_info_read_offset_u32(&info, desc->count_offset);
9006		size  = bpf_prog_info_read_offset_u32(&info, desc->size_offset);
9007
9008		data_len += count * size;
9009	}
9010
9011	/* step 3: allocate continuous memory */
9012	data_len = roundup(data_len, sizeof(__u64));
9013	info_linear = malloc(sizeof(struct bpf_prog_info_linear) + data_len);
9014	if (!info_linear)
9015		return ERR_PTR(-ENOMEM);
9016
9017	/* step 4: fill data to info_linear->info */
9018	info_linear->arrays = arrays;
9019	memset(&info_linear->info, 0, sizeof(info));
9020	ptr = info_linear->data;
9021
9022	for (i = BPF_PROG_INFO_FIRST_ARRAY; i < BPF_PROG_INFO_LAST_ARRAY; ++i) {
9023		struct bpf_prog_info_array_desc *desc;
9024		__u32 count, size;
9025
9026		if ((arrays & (1UL << i)) == 0)
9027			continue;
9028
9029		desc  = bpf_prog_info_array_desc + i;
9030		count = bpf_prog_info_read_offset_u32(&info, desc->count_offset);
9031		size  = bpf_prog_info_read_offset_u32(&info, desc->size_offset);
9032		bpf_prog_info_set_offset_u32(&info_linear->info,
9033					     desc->count_offset, count);
9034		bpf_prog_info_set_offset_u32(&info_linear->info,
9035					     desc->size_offset, size);
9036		bpf_prog_info_set_offset_u64(&info_linear->info,
9037					     desc->array_offset,
9038					     ptr_to_u64(ptr));
9039		ptr += count * size;
9040	}
9041
9042	/* step 5: call syscall again to get required arrays */
9043	err = bpf_obj_get_info_by_fd(fd, &info_linear->info, &info_len);
9044	if (err) {
9045		pr_debug("can't get prog info: %s", strerror(errno));
9046		free(info_linear);
9047		return ERR_PTR(-EFAULT);
9048	}
9049
9050	/* step 6: verify the data */
9051	for (i = BPF_PROG_INFO_FIRST_ARRAY; i < BPF_PROG_INFO_LAST_ARRAY; ++i) {
9052		struct bpf_prog_info_array_desc *desc;
9053		__u32 v1, v2;
9054
9055		if ((arrays & (1UL << i)) == 0)
9056			continue;
9057
9058		desc = bpf_prog_info_array_desc + i;
9059		v1 = bpf_prog_info_read_offset_u32(&info, desc->count_offset);
9060		v2 = bpf_prog_info_read_offset_u32(&info_linear->info,
9061						   desc->count_offset);
9062		if (v1 != v2)
9063			pr_warn("%s: mismatch in element count\n", __func__);
9064
9065		v1 = bpf_prog_info_read_offset_u32(&info, desc->size_offset);
9066		v2 = bpf_prog_info_read_offset_u32(&info_linear->info,
9067						   desc->size_offset);
9068		if (v1 != v2)
9069			pr_warn("%s: mismatch in rec size\n", __func__);
9070	}
9071
9072	/* step 7: update info_len and data_len */
9073	info_linear->info_len = sizeof(struct bpf_prog_info);
9074	info_linear->data_len = data_len;
9075
9076	return info_linear;
9077}
9078
9079void bpf_program__bpil_addr_to_offs(struct bpf_prog_info_linear *info_linear)
9080{
9081	int i;
9082
9083	for (i = BPF_PROG_INFO_FIRST_ARRAY; i < BPF_PROG_INFO_LAST_ARRAY; ++i) {
9084		struct bpf_prog_info_array_desc *desc;
9085		__u64 addr, offs;
9086
9087		if ((info_linear->arrays & (1UL << i)) == 0)
9088			continue;
9089
9090		desc = bpf_prog_info_array_desc + i;
9091		addr = bpf_prog_info_read_offset_u64(&info_linear->info,
9092						     desc->array_offset);
9093		offs = addr - ptr_to_u64(info_linear->data);
9094		bpf_prog_info_set_offset_u64(&info_linear->info,
9095					     desc->array_offset, offs);
9096	}
9097}
9098
9099void bpf_program__bpil_offs_to_addr(struct bpf_prog_info_linear *info_linear)
9100{
9101	int i;
9102
9103	for (i = BPF_PROG_INFO_FIRST_ARRAY; i < BPF_PROG_INFO_LAST_ARRAY; ++i) {
9104		struct bpf_prog_info_array_desc *desc;
9105		__u64 addr, offs;
9106
9107		if ((info_linear->arrays & (1UL << i)) == 0)
9108			continue;
9109
9110		desc = bpf_prog_info_array_desc + i;
9111		offs = bpf_prog_info_read_offset_u64(&info_linear->info,
9112						     desc->array_offset);
9113		addr = offs + ptr_to_u64(info_linear->data);
9114		bpf_prog_info_set_offset_u64(&info_linear->info,
9115					     desc->array_offset, addr);
9116	}
9117}
9118
9119int bpf_program__set_attach_target(struct bpf_program *prog,
9120				   int attach_prog_fd,
9121				   const char *attach_func_name)
9122{
9123	int btf_id;
9124
9125	if (!prog || attach_prog_fd < 0 || !attach_func_name)
9126		return -EINVAL;
9127
9128	if (attach_prog_fd)
9129		btf_id = libbpf_find_prog_btf_id(attach_func_name,
9130						 attach_prog_fd);
9131	else
9132		btf_id = __find_vmlinux_btf_id(prog->obj->btf_vmlinux,
9133					       attach_func_name,
9134					       prog->expected_attach_type);
9135
9136	if (btf_id < 0)
9137		return btf_id;
9138
9139	prog->attach_btf_id = btf_id;
9140	prog->attach_prog_fd = attach_prog_fd;
9141	return 0;
9142}
9143
9144int parse_cpu_mask_str(const char *s, bool **mask, int *mask_sz)
9145{
9146	int err = 0, n, len, start, end = -1;
9147	bool *tmp;
9148
9149	*mask = NULL;
9150	*mask_sz = 0;
9151
9152	/* Each sub string separated by ',' has format \d+-\d+ or \d+ */
9153	while (*s) {
9154		if (*s == ',' || *s == '\n') {
9155			s++;
9156			continue;
9157		}
9158		n = sscanf(s, "%d%n-%d%n", &start, &len, &end, &len);
9159		if (n <= 0 || n > 2) {
9160			pr_warn("Failed to get CPU range %s: %d\n", s, n);
9161			err = -EINVAL;
9162			goto cleanup;
9163		} else if (n == 1) {
9164			end = start;
9165		}
9166		if (start < 0 || start > end) {
9167			pr_warn("Invalid CPU range [%d,%d] in %s\n",
9168				start, end, s);
9169			err = -EINVAL;
9170			goto cleanup;
9171		}
9172		tmp = realloc(*mask, end + 1);
9173		if (!tmp) {
9174			err = -ENOMEM;
9175			goto cleanup;
9176		}
9177		*mask = tmp;
9178		memset(tmp + *mask_sz, 0, start - *mask_sz);
9179		memset(tmp + start, 1, end - start + 1);
9180		*mask_sz = end + 1;
9181		s += len;
9182	}
9183	if (!*mask_sz) {
9184		pr_warn("Empty CPU range\n");
9185		return -EINVAL;
9186	}
9187	return 0;
9188cleanup:
9189	free(*mask);
9190	*mask = NULL;
9191	return err;
9192}
9193
9194int parse_cpu_mask_file(const char *fcpu, bool **mask, int *mask_sz)
9195{
9196	int fd, err = 0, len;
9197	char buf[128];
9198
9199	fd = open(fcpu, O_RDONLY);
9200	if (fd < 0) {
9201		err = -errno;
9202		pr_warn("Failed to open cpu mask file %s: %d\n", fcpu, err);
9203		return err;
9204	}
9205	len = read(fd, buf, sizeof(buf));
9206	close(fd);
9207	if (len <= 0) {
9208		err = len ? -errno : -EINVAL;
9209		pr_warn("Failed to read cpu mask from %s: %d\n", fcpu, err);
9210		return err;
9211	}
9212	if (len >= sizeof(buf)) {
9213		pr_warn("CPU mask is too big in file %s\n", fcpu);
9214		return -E2BIG;
9215	}
9216	buf[len] = '\0';
9217
9218	return parse_cpu_mask_str(buf, mask, mask_sz);
9219}
9220
9221int libbpf_num_possible_cpus(void)
9222{
9223	static const char *fcpu = "/sys/devices/system/cpu/possible";
9224	static int cpus;
9225	int err, n, i, tmp_cpus;
9226	bool *mask;
9227
9228	tmp_cpus = READ_ONCE(cpus);
9229	if (tmp_cpus > 0)
9230		return tmp_cpus;
9231
9232	err = parse_cpu_mask_file(fcpu, &mask, &n);
9233	if (err)
9234		return err;
9235
9236	tmp_cpus = 0;
9237	for (i = 0; i < n; i++) {
9238		if (mask[i])
9239			tmp_cpus++;
9240	}
9241	free(mask);
9242
9243	WRITE_ONCE(cpus, tmp_cpus);
9244	return tmp_cpus;
9245}
9246
9247int bpf_object__open_skeleton(struct bpf_object_skeleton *s,
9248			      const struct bpf_object_open_opts *opts)
9249{
9250	DECLARE_LIBBPF_OPTS(bpf_object_open_opts, skel_opts,
9251		.object_name = s->name,
9252	);
9253	struct bpf_object *obj;
9254	int i;
9255
9256	/* Attempt to preserve opts->object_name, unless overriden by user
9257	 * explicitly. Overwriting object name for skeletons is discouraged,
9258	 * as it breaks global data maps, because they contain object name
9259	 * prefix as their own map name prefix. When skeleton is generated,
9260	 * bpftool is making an assumption that this name will stay the same.
9261	 */
9262	if (opts) {
9263		memcpy(&skel_opts, opts, sizeof(*opts));
9264		if (!opts->object_name)
9265			skel_opts.object_name = s->name;
9266	}
9267
9268	obj = bpf_object__open_mem(s->data, s->data_sz, &skel_opts);
9269	if (IS_ERR(obj)) {
9270		pr_warn("failed to initialize skeleton BPF object '%s': %ld\n",
9271			s->name, PTR_ERR(obj));
9272		return PTR_ERR(obj);
9273	}
9274
9275	*s->obj = obj;
9276
9277	for (i = 0; i < s->map_cnt; i++) {
9278		struct bpf_map **map = s->maps[i].map;
9279		const char *name = s->maps[i].name;
9280		void **mmaped = s->maps[i].mmaped;
9281
9282		*map = bpf_object__find_map_by_name(obj, name);
9283		if (!*map) {
9284			pr_warn("failed to find skeleton map '%s'\n", name);
9285			return -ESRCH;
9286		}
9287
9288		/* externs shouldn't be pre-setup from user code */
9289		if (mmaped && (*map)->libbpf_type != LIBBPF_MAP_KCONFIG)
9290			*mmaped = (*map)->mmaped;
9291	}
9292
9293	for (i = 0; i < s->prog_cnt; i++) {
9294		struct bpf_program **prog = s->progs[i].prog;
9295		const char *name = s->progs[i].name;
9296
9297		*prog = bpf_object__find_program_by_name(obj, name);
9298		if (!*prog) {
9299			pr_warn("failed to find skeleton program '%s'\n", name);
9300			return -ESRCH;
9301		}
9302	}
9303
9304	return 0;
9305}
9306
9307int bpf_object__load_skeleton(struct bpf_object_skeleton *s)
9308{
9309	int i, err;
9310
9311	err = bpf_object__load(*s->obj);
9312	if (err) {
9313		pr_warn("failed to load BPF skeleton '%s': %d\n", s->name, err);
9314		return err;
9315	}
9316
9317	for (i = 0; i < s->map_cnt; i++) {
9318		struct bpf_map *map = *s->maps[i].map;
9319		size_t mmap_sz = bpf_map_mmap_sz(map);
9320		int prot, map_fd = bpf_map__fd(map);
9321		void **mmaped = s->maps[i].mmaped;
9322
9323		if (!mmaped)
9324			continue;
9325
9326		if (!(map->def.map_flags & BPF_F_MMAPABLE)) {
9327			*mmaped = NULL;
9328			continue;
9329		}
9330
9331		if (map->def.map_flags & BPF_F_RDONLY_PROG)
9332			prot = PROT_READ;
9333		else
9334			prot = PROT_READ | PROT_WRITE;
9335
9336		/* Remap anonymous mmap()-ed "map initialization image" as
9337		 * a BPF map-backed mmap()-ed memory, but preserving the same
9338		 * memory address. This will cause kernel to change process'
9339		 * page table to point to a different piece of kernel memory,
9340		 * but from userspace point of view memory address (and its
9341		 * contents, being identical at this point) will stay the
9342		 * same. This mapping will be released by bpf_object__close()
9343		 * as per normal clean up procedure, so we don't need to worry
9344		 * about it from skeleton's clean up perspective.
9345		 */
9346		*mmaped = mmap(map->mmaped, mmap_sz, prot,
9347				MAP_SHARED | MAP_FIXED, map_fd, 0);
9348		if (*mmaped == MAP_FAILED) {
9349			err = -errno;
9350			*mmaped = NULL;
9351			pr_warn("failed to re-mmap() map '%s': %d\n",
9352				 bpf_map__name(map), err);
9353			return err;
9354		}
9355	}
9356
9357	return 0;
9358}
9359
9360int bpf_object__attach_skeleton(struct bpf_object_skeleton *s)
9361{
9362	int i;
9363
9364	for (i = 0; i < s->prog_cnt; i++) {
9365		struct bpf_program *prog = *s->progs[i].prog;
9366		struct bpf_link **link = s->progs[i].link;
9367		const struct bpf_sec_def *sec_def;
9368		const char *sec_name = bpf_program__title(prog, false);
9369
9370		if (!prog->load)
9371			continue;
9372
9373		sec_def = find_sec_def(sec_name);
9374		if (!sec_def || !sec_def->attach_fn)
9375			continue;
9376
9377		*link = sec_def->attach_fn(sec_def, prog);
9378		if (IS_ERR(*link)) {
9379			pr_warn("failed to auto-attach program '%s': %ld\n",
9380				bpf_program__name(prog), PTR_ERR(*link));
9381			return PTR_ERR(*link);
9382		}
9383	}
9384
9385	return 0;
9386}
9387
9388void bpf_object__detach_skeleton(struct bpf_object_skeleton *s)
9389{
9390	int i;
9391
9392	for (i = 0; i < s->prog_cnt; i++) {
9393		struct bpf_link **link = s->progs[i].link;
9394
9395		bpf_link__destroy(*link);
9396		*link = NULL;
9397	}
9398}
9399
9400void bpf_object__destroy_skeleton(struct bpf_object_skeleton *s)
9401{
9402	if (s->progs)
9403		bpf_object__detach_skeleton(s);
9404	if (s->obj)
9405		bpf_object__close(*s->obj);
9406	free(s->maps);
9407	free(s->progs);
9408	free(s);
9409}