1// SPDX-License-Identifier: GPL-2.0
   2#include <fcntl.h>
   3#include <stdio.h>
   4#include <errno.h>
   5#include <stdlib.h>
   6#include <string.h>
   7#include <unistd.h>
   8#include <inttypes.h>
   9
  10#include "dso.h"
  11#include "map.h"
  12#include "map_groups.h"
  13#include "symbol.h"
  14#include "symsrc.h"
 
 
  15#include "demangle-java.h"
  16#include "demangle-rust.h"
  17#include "machine.h"
  18#include "vdso.h"
  19#include "debug.h"
  20#include "util/copyfile.h"
  21#include <linux/ctype.h>
  22#include <linux/kernel.h>
  23#include <linux/zalloc.h>
 
  24#include <symbol/kallsyms.h>
  25#include <internal/lib.h>
  26
 
 
 
 
 
 
 
 
 
 
 
 
  27#ifndef EM_AARCH64
  28#define EM_AARCH64	183  /* ARM 64 bit */
  29#endif
  30
 
 
 
 
  31#ifndef ELF32_ST_VISIBILITY
  32#define ELF32_ST_VISIBILITY(o)	((o) & 0x03)
  33#endif
  34
  35/* For ELF64 the definitions are the same.  */
  36#ifndef ELF64_ST_VISIBILITY
  37#define ELF64_ST_VISIBILITY(o)	ELF32_ST_VISIBILITY (o)
  38#endif
  39
  40/* How to extract information held in the st_other field.  */
  41#ifndef GELF_ST_VISIBILITY
  42#define GELF_ST_VISIBILITY(val)	ELF64_ST_VISIBILITY (val)
  43#endif
  44
  45typedef Elf64_Nhdr GElf_Nhdr;
  46
  47#ifndef DMGL_PARAMS
  48#define DMGL_NO_OPTS     0              /* For readability... */
  49#define DMGL_PARAMS      (1 << 0)       /* Include function args */
  50#define DMGL_ANSI        (1 << 1)       /* Include const, volatile, etc */
  51#endif
  52
  53#ifdef HAVE_CPLUS_DEMANGLE_SUPPORT
  54extern char *cplus_demangle(const char *, int);
  55
  56static inline char *bfd_demangle(void __maybe_unused *v, const char *c, int i)
  57{
  58	return cplus_demangle(c, i);
  59}
  60#else
  61#ifdef NO_DEMANGLE
  62static inline char *bfd_demangle(void __maybe_unused *v,
  63				 const char __maybe_unused *c,
  64				 int __maybe_unused i)
  65{
  66	return NULL;
  67}
  68#else
  69#define PACKAGE 'perf'
  70#include <bfd.h>
  71#endif
  72#endif
  73
  74#ifndef HAVE_ELF_GETPHDRNUM_SUPPORT
  75static int elf_getphdrnum(Elf *elf, size_t *dst)
  76{
  77	GElf_Ehdr gehdr;
  78	GElf_Ehdr *ehdr;
  79
  80	ehdr = gelf_getehdr(elf, &gehdr);
  81	if (!ehdr)
  82		return -1;
  83
  84	*dst = ehdr->e_phnum;
  85
  86	return 0;
  87}
  88#endif
  89
  90#ifndef HAVE_ELF_GETSHDRSTRNDX_SUPPORT
  91static int elf_getshdrstrndx(Elf *elf __maybe_unused, size_t *dst __maybe_unused)
  92{
  93	pr_err("%s: update your libelf to > 0.140, this one lacks elf_getshdrstrndx().\n", __func__);
  94	return -1;
  95}
  96#endif
  97
  98#ifndef NT_GNU_BUILD_ID
  99#define NT_GNU_BUILD_ID 3
 100#endif
 101
 102/**
 103 * elf_symtab__for_each_symbol - iterate thru all the symbols
 104 *
 105 * @syms: struct elf_symtab instance to iterate
 106 * @idx: uint32_t idx
 107 * @sym: GElf_Sym iterator
 108 */
 109#define elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) \
 110	for (idx = 0, gelf_getsym(syms, idx, &sym);\
 111	     idx < nr_syms; \
 112	     idx++, gelf_getsym(syms, idx, &sym))
 113
 114static inline uint8_t elf_sym__type(const GElf_Sym *sym)
 115{
 116	return GELF_ST_TYPE(sym->st_info);
 117}
 118
 119static inline uint8_t elf_sym__visibility(const GElf_Sym *sym)
 120{
 121	return GELF_ST_VISIBILITY(sym->st_other);
 122}
 123
 124#ifndef STT_GNU_IFUNC
 125#define STT_GNU_IFUNC 10
 126#endif
 127
 128static inline int elf_sym__is_function(const GElf_Sym *sym)
 129{
 130	return (elf_sym__type(sym) == STT_FUNC ||
 131		elf_sym__type(sym) == STT_GNU_IFUNC) &&
 132	       sym->st_name != 0 &&
 133	       sym->st_shndx != SHN_UNDEF;
 134}
 135
 136static inline bool elf_sym__is_object(const GElf_Sym *sym)
 137{
 138	return elf_sym__type(sym) == STT_OBJECT &&
 139		sym->st_name != 0 &&
 140		sym->st_shndx != SHN_UNDEF;
 141}
 142
 143static inline int elf_sym__is_label(const GElf_Sym *sym)
 144{
 145	return elf_sym__type(sym) == STT_NOTYPE &&
 146		sym->st_name != 0 &&
 147		sym->st_shndx != SHN_UNDEF &&
 148		sym->st_shndx != SHN_ABS &&
 149		elf_sym__visibility(sym) != STV_HIDDEN &&
 150		elf_sym__visibility(sym) != STV_INTERNAL;
 151}
 152
 153static bool elf_sym__filter(GElf_Sym *sym)
 154{
 155	return elf_sym__is_function(sym) || elf_sym__is_object(sym);
 156}
 157
 158static inline const char *elf_sym__name(const GElf_Sym *sym,
 159					const Elf_Data *symstrs)
 160{
 161	return symstrs->d_buf + sym->st_name;
 162}
 163
 164static inline const char *elf_sec__name(const GElf_Shdr *shdr,
 165					const Elf_Data *secstrs)
 166{
 167	return secstrs->d_buf + shdr->sh_name;
 168}
 169
 170static inline int elf_sec__is_text(const GElf_Shdr *shdr,
 171					const Elf_Data *secstrs)
 172{
 173	return strstr(elf_sec__name(shdr, secstrs), "text") != NULL;
 174}
 175
 176static inline bool elf_sec__is_data(const GElf_Shdr *shdr,
 177				    const Elf_Data *secstrs)
 178{
 179	return strstr(elf_sec__name(shdr, secstrs), "data") != NULL;
 180}
 181
 182static bool elf_sec__filter(GElf_Shdr *shdr, Elf_Data *secstrs)
 183{
 184	return elf_sec__is_text(shdr, secstrs) || 
 185	       elf_sec__is_data(shdr, secstrs);
 186}
 187
 188static size_t elf_addr_to_index(Elf *elf, GElf_Addr addr)
 189{
 190	Elf_Scn *sec = NULL;
 191	GElf_Shdr shdr;
 192	size_t cnt = 1;
 193
 194	while ((sec = elf_nextscn(elf, sec)) != NULL) {
 195		gelf_getshdr(sec, &shdr);
 196
 197		if ((addr >= shdr.sh_addr) &&
 198		    (addr < (shdr.sh_addr + shdr.sh_size)))
 199			return cnt;
 200
 201		++cnt;
 202	}
 203
 204	return -1;
 205}
 206
 207Elf_Scn *elf_section_by_name(Elf *elf, GElf_Ehdr *ep,
 208			     GElf_Shdr *shp, const char *name, size_t *idx)
 209{
 210	Elf_Scn *sec = NULL;
 211	size_t cnt = 1;
 212
 213	/* Elf is corrupted/truncated, avoid calling elf_strptr. */
 214	if (!elf_rawdata(elf_getscn(elf, ep->e_shstrndx), NULL))
 215		return NULL;
 216
 217	while ((sec = elf_nextscn(elf, sec)) != NULL) {
 218		char *str;
 219
 220		gelf_getshdr(sec, shp);
 221		str = elf_strptr(elf, ep->e_shstrndx, shp->sh_name);
 222		if (str && !strcmp(name, str)) {
 223			if (idx)
 224				*idx = cnt;
 225			return sec;
 226		}
 227		++cnt;
 228	}
 229
 230	return NULL;
 231}
 232
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 233static bool want_demangle(bool is_kernel_sym)
 234{
 235	return is_kernel_sym ? symbol_conf.demangle_kernel : symbol_conf.demangle;
 236}
 237
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 238static char *demangle_sym(struct dso *dso, int kmodule, const char *elf_name)
 239{
 240	int demangle_flags = verbose > 0 ? (DMGL_PARAMS | DMGL_ANSI) : DMGL_NO_OPTS;
 241	char *demangled = NULL;
 242
 243	/*
 244	 * We need to figure out if the object was created from C++ sources
 245	 * DWARF DW_compile_unit has this, but we don't always have access
 246	 * to it...
 247	 */
 248	if (!want_demangle(dso->kernel || kmodule))
 249	    return demangled;
 250
 251	demangled = bfd_demangle(NULL, elf_name, demangle_flags);
 252	if (demangled == NULL)
 253		demangled = java_demangle_sym(elf_name, JAVA_DEMANGLE_NORET);
 
 
 
 
 254	else if (rust_is_mangled(demangled))
 255		/*
 256		    * Input to Rust demangling is the BFD-demangled
 257		    * name which it Rust-demangles in place.
 258		    */
 259		rust_demangle_sym(demangled);
 260
 261	return demangled;
 262}
 263
 264#define elf_section__for_each_rel(reldata, pos, pos_mem, idx, nr_entries) \
 265	for (idx = 0, pos = gelf_getrel(reldata, 0, &pos_mem); \
 266	     idx < nr_entries; \
 267	     ++idx, pos = gelf_getrel(reldata, idx, &pos_mem))
 268
 269#define elf_section__for_each_rela(reldata, pos, pos_mem, idx, nr_entries) \
 270	for (idx = 0, pos = gelf_getrela(reldata, 0, &pos_mem); \
 271	     idx < nr_entries; \
 272	     ++idx, pos = gelf_getrela(reldata, idx, &pos_mem))
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 273
 274/*
 275 * We need to check if we have a .dynsym, so that we can handle the
 276 * .plt, synthesizing its symbols, that aren't on the symtabs (be it
 277 * .dynsym or .symtab).
 278 * And always look at the original dso, not at debuginfo packages, that
 279 * have the PLT data stripped out (shdr_rel_plt.sh_type == SHT_NOBITS).
 280 */
 281int dso__synthesize_plt_symbols(struct dso *dso, struct symsrc *ss)
 282{
 283	uint32_t nr_rel_entries, idx;
 284	GElf_Sym sym;
 285	u64 plt_offset, plt_header_size, plt_entry_size;
 286	GElf_Shdr shdr_plt;
 287	struct symbol *f;
 288	GElf_Shdr shdr_rel_plt, shdr_dynsym;
 289	Elf_Data *reldata, *syms, *symstrs;
 290	Elf_Scn *scn_plt_rel, *scn_symstrs, *scn_dynsym;
 291	size_t dynsym_idx;
 292	GElf_Ehdr ehdr;
 293	char sympltname[1024];
 294	Elf *elf;
 295	int nr = 0, symidx, err = 0;
 296
 297	if (!ss->dynsym)
 298		return 0;
 299
 300	elf = ss->elf;
 301	ehdr = ss->ehdr;
 302
 303	scn_dynsym = ss->dynsym;
 304	shdr_dynsym = ss->dynshdr;
 305	dynsym_idx = ss->dynsym_idx;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 306
 307	if (scn_dynsym == NULL)
 
 
 308		goto out_elf_end;
 309
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 310	scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt,
 311					  ".rela.plt", NULL);
 312	if (scn_plt_rel == NULL) {
 313		scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt,
 314						  ".rel.plt", NULL);
 315		if (scn_plt_rel == NULL)
 316			goto out_elf_end;
 317	}
 318
 319	err = -1;
 
 
 320
 321	if (shdr_rel_plt.sh_link != dynsym_idx)
 322		goto out_elf_end;
 323
 324	if (elf_section_by_name(elf, &ehdr, &shdr_plt, ".plt", NULL) == NULL)
 
 
 
 
 
 
 
 
 
 
 325		goto out_elf_end;
 
 
 
 
 326
 327	/*
 328	 * Fetch the relocation section to find the idxes to the GOT
 329	 * and the symbols in the .dynsym they refer to.
 330	 */
 331	reldata = elf_getdata(scn_plt_rel, NULL);
 332	if (reldata == NULL)
 333		goto out_elf_end;
 334
 335	syms = elf_getdata(scn_dynsym, NULL);
 336	if (syms == NULL)
 337		goto out_elf_end;
 338
 339	scn_symstrs = elf_getscn(elf, shdr_dynsym.sh_link);
 340	if (scn_symstrs == NULL)
 341		goto out_elf_end;
 342
 343	symstrs = elf_getdata(scn_symstrs, NULL);
 344	if (symstrs == NULL)
 345		goto out_elf_end;
 346
 347	if (symstrs->d_size == 0)
 348		goto out_elf_end;
 349
 350	nr_rel_entries = shdr_rel_plt.sh_size / shdr_rel_plt.sh_entsize;
 351	plt_offset = shdr_plt.sh_offset;
 352	switch (ehdr.e_machine) {
 353		case EM_ARM:
 354			plt_header_size = 20;
 355			plt_entry_size = 12;
 356			break;
 357
 358		case EM_AARCH64:
 359			plt_header_size = 32;
 360			plt_entry_size = 16;
 361			break;
 362
 363		case EM_SPARC:
 364			plt_header_size = 48;
 365			plt_entry_size = 12;
 366			break;
 367
 368		case EM_SPARCV9:
 369			plt_header_size = 128;
 370			plt_entry_size = 32;
 371			break;
 372
 373		default: /* FIXME: s390/alpha/mips/parisc/poperpc/sh/xtensa need to be checked */
 374			plt_header_size = shdr_plt.sh_entsize;
 375			plt_entry_size = shdr_plt.sh_entsize;
 376			break;
 377	}
 378	plt_offset += plt_header_size;
 379
 380	if (shdr_rel_plt.sh_type == SHT_RELA) {
 381		GElf_Rela pos_mem, *pos;
 
 
 
 
 382
 383		elf_section__for_each_rela(reldata, pos, pos_mem, idx,
 384					   nr_rel_entries) {
 385			const char *elf_name = NULL;
 386			char *demangled = NULL;
 387			symidx = GELF_R_SYM(pos->r_info);
 388			gelf_getsym(syms, symidx, &sym);
 389
 390			elf_name = elf_sym__name(&sym, symstrs);
 391			demangled = demangle_sym(dso, 0, elf_name);
 392			if (demangled != NULL)
 393				elf_name = demangled;
 394			snprintf(sympltname, sizeof(sympltname),
 395				 "%s@plt", elf_name);
 396			free(demangled);
 397
 398			f = symbol__new(plt_offset, plt_entry_size,
 399					STB_GLOBAL, STT_FUNC, sympltname);
 400			if (!f)
 401				goto out_elf_end;
 402
 403			plt_offset += plt_entry_size;
 404			symbols__insert(&dso->symbols, f);
 405			++nr;
 406		}
 407	} else if (shdr_rel_plt.sh_type == SHT_REL) {
 408		GElf_Rel pos_mem, *pos;
 409		elf_section__for_each_rel(reldata, pos, pos_mem, idx,
 410					  nr_rel_entries) {
 411			const char *elf_name = NULL;
 412			char *demangled = NULL;
 413			symidx = GELF_R_SYM(pos->r_info);
 414			gelf_getsym(syms, symidx, &sym);
 415
 416			elf_name = elf_sym__name(&sym, symstrs);
 417			demangled = demangle_sym(dso, 0, elf_name);
 418			if (demangled != NULL)
 419				elf_name = demangled;
 420			snprintf(sympltname, sizeof(sympltname),
 421				 "%s@plt", elf_name);
 422			free(demangled);
 423
 424			f = symbol__new(plt_offset, plt_entry_size,
 425					STB_GLOBAL, STT_FUNC, sympltname);
 426			if (!f)
 427				goto out_elf_end;
 428
 429			plt_offset += plt_entry_size;
 430			symbols__insert(&dso->symbols, f);
 431			++nr;
 432		}
 433	}
 434
 435	err = 0;
 436out_elf_end:
 
 437	if (err == 0)
 438		return nr;
 439	pr_debug("%s: problems reading %s PLT info.\n",
 440		 __func__, dso->long_name);
 441	return 0;
 442}
 443
 444char *dso__demangle_sym(struct dso *dso, int kmodule, const char *elf_name)
 445{
 446	return demangle_sym(dso, kmodule, elf_name);
 447}
 448
 449/*
 450 * Align offset to 4 bytes as needed for note name and descriptor data.
 451 */
 452#define NOTE_ALIGN(n) (((n) + 3) & -4U)
 453
 454static int elf_read_build_id(Elf *elf, void *bf, size_t size)
 455{
 456	int err = -1;
 457	GElf_Ehdr ehdr;
 458	GElf_Shdr shdr;
 459	Elf_Data *data;
 460	Elf_Scn *sec;
 461	Elf_Kind ek;
 462	void *ptr;
 463
 464	if (size < BUILD_ID_SIZE)
 465		goto out;
 466
 467	ek = elf_kind(elf);
 468	if (ek != ELF_K_ELF)
 469		goto out;
 470
 471	if (gelf_getehdr(elf, &ehdr) == NULL) {
 472		pr_err("%s: cannot get elf header.\n", __func__);
 473		goto out;
 474	}
 475
 476	/*
 477	 * Check following sections for notes:
 478	 *   '.note.gnu.build-id'
 479	 *   '.notes'
 480	 *   '.note' (VDSO specific)
 481	 */
 482	do {
 483		sec = elf_section_by_name(elf, &ehdr, &shdr,
 484					  ".note.gnu.build-id", NULL);
 485		if (sec)
 486			break;
 487
 488		sec = elf_section_by_name(elf, &ehdr, &shdr,
 489					  ".notes", NULL);
 490		if (sec)
 491			break;
 492
 493		sec = elf_section_by_name(elf, &ehdr, &shdr,
 494					  ".note", NULL);
 495		if (sec)
 496			break;
 497
 498		return err;
 499
 500	} while (0);
 501
 502	data = elf_getdata(sec, NULL);
 503	if (data == NULL)
 504		goto out;
 505
 506	ptr = data->d_buf;
 507	while (ptr < (data->d_buf + data->d_size)) {
 508		GElf_Nhdr *nhdr = ptr;
 509		size_t namesz = NOTE_ALIGN(nhdr->n_namesz),
 510		       descsz = NOTE_ALIGN(nhdr->n_descsz);
 511		const char *name;
 512
 513		ptr += sizeof(*nhdr);
 514		name = ptr;
 515		ptr += namesz;
 516		if (nhdr->n_type == NT_GNU_BUILD_ID &&
 517		    nhdr->n_namesz == sizeof("GNU")) {
 518			if (memcmp(name, "GNU", sizeof("GNU")) == 0) {
 519				size_t sz = min(size, descsz);
 520				memcpy(bf, ptr, sz);
 521				memset(bf + sz, 0, size - sz);
 522				err = descsz;
 523				break;
 524			}
 525		}
 526		ptr += descsz;
 527	}
 528
 529out:
 530	return err;
 531}
 532
 533int filename__read_build_id(const char *filename, void *bf, size_t size)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 534{
 
 535	int fd, err = -1;
 536	Elf *elf;
 537
 538	if (size < BUILD_ID_SIZE)
 539		goto out;
 540
 541	fd = open(filename, O_RDONLY);
 542	if (fd < 0)
 543		goto out;
 544
 545	elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
 546	if (elf == NULL) {
 547		pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename);
 548		goto out_close;
 549	}
 550
 551	err = elf_read_build_id(elf, bf, size);
 
 
 552
 553	elf_end(elf);
 554out_close:
 555	close(fd);
 556out:
 557	return err;
 558}
 559
 560int sysfs__read_build_id(const char *filename, void *build_id, size_t size)
 
 
 561{
 562	int fd, err = -1;
 
 
 563
 564	if (size < BUILD_ID_SIZE)
 565		goto out;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 566
 567	fd = open(filename, O_RDONLY);
 568	if (fd < 0)
 569		goto out;
 570
 571	while (1) {
 572		char bf[BUFSIZ];
 573		GElf_Nhdr nhdr;
 574		size_t namesz, descsz;
 575
 576		if (read(fd, &nhdr, sizeof(nhdr)) != sizeof(nhdr))
 577			break;
 578
 579		namesz = NOTE_ALIGN(nhdr.n_namesz);
 580		descsz = NOTE_ALIGN(nhdr.n_descsz);
 581		if (nhdr.n_type == NT_GNU_BUILD_ID &&
 582		    nhdr.n_namesz == sizeof("GNU")) {
 583			if (read(fd, bf, namesz) != (ssize_t)namesz)
 584				break;
 585			if (memcmp(bf, "GNU", sizeof("GNU")) == 0) {
 586				size_t sz = min(descsz, size);
 587				if (read(fd, build_id, sz) == (ssize_t)sz) {
 588					memset(build_id + sz, 0, size - sz);
 
 589					err = 0;
 590					break;
 591				}
 592			} else if (read(fd, bf, descsz) != (ssize_t)descsz)
 593				break;
 594		} else {
 595			int n = namesz + descsz;
 596
 597			if (n > (int)sizeof(bf)) {
 598				n = sizeof(bf);
 599				pr_debug("%s: truncating reading of build id in sysfs file %s: n_namesz=%u, n_descsz=%u.\n",
 600					 __func__, filename, nhdr.n_namesz, nhdr.n_descsz);
 601			}
 602			if (read(fd, bf, n) != n)
 603				break;
 604		}
 605	}
 606	close(fd);
 607out:
 608	return err;
 609}
 610
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 611int filename__read_debuglink(const char *filename, char *debuglink,
 612			     size_t size)
 613{
 614	int fd, err = -1;
 615	Elf *elf;
 616	GElf_Ehdr ehdr;
 617	GElf_Shdr shdr;
 618	Elf_Data *data;
 619	Elf_Scn *sec;
 620	Elf_Kind ek;
 621
 622	fd = open(filename, O_RDONLY);
 623	if (fd < 0)
 624		goto out;
 625
 626	elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
 627	if (elf == NULL) {
 628		pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename);
 629		goto out_close;
 630	}
 631
 632	ek = elf_kind(elf);
 633	if (ek != ELF_K_ELF)
 634		goto out_elf_end;
 635
 636	if (gelf_getehdr(elf, &ehdr) == NULL) {
 637		pr_err("%s: cannot get elf header.\n", __func__);
 638		goto out_elf_end;
 639	}
 640
 641	sec = elf_section_by_name(elf, &ehdr, &shdr,
 642				  ".gnu_debuglink", NULL);
 643	if (sec == NULL)
 644		goto out_elf_end;
 645
 646	data = elf_getdata(sec, NULL);
 647	if (data == NULL)
 648		goto out_elf_end;
 649
 650	/* the start of this section is a zero-terminated string */
 651	strncpy(debuglink, data->d_buf, size);
 652
 653	err = 0;
 654
 655out_elf_end:
 656	elf_end(elf);
 657out_close:
 658	close(fd);
 659out:
 660	return err;
 661}
 662
 
 
 663static int dso__swap_init(struct dso *dso, unsigned char eidata)
 664{
 665	static unsigned int const endian = 1;
 666
 667	dso->needs_swap = DSO_SWAP__NO;
 668
 669	switch (eidata) {
 670	case ELFDATA2LSB:
 671		/* We are big endian, DSO is little endian. */
 672		if (*(unsigned char const *)&endian != 1)
 673			dso->needs_swap = DSO_SWAP__YES;
 674		break;
 675
 676	case ELFDATA2MSB:
 677		/* We are little endian, DSO is big endian. */
 678		if (*(unsigned char const *)&endian != 0)
 679			dso->needs_swap = DSO_SWAP__YES;
 680		break;
 681
 682	default:
 683		pr_err("unrecognized DSO data encoding %d\n", eidata);
 684		return -EINVAL;
 685	}
 686
 687	return 0;
 688}
 689
 690bool symsrc__possibly_runtime(struct symsrc *ss)
 691{
 692	return ss->dynsym || ss->opdsec;
 693}
 694
 695bool symsrc__has_symtab(struct symsrc *ss)
 696{
 697	return ss->symtab != NULL;
 698}
 699
 700void symsrc__destroy(struct symsrc *ss)
 701{
 702	zfree(&ss->name);
 703	elf_end(ss->elf);
 704	close(ss->fd);
 705}
 706
 707bool __weak elf__needs_adjust_symbols(GElf_Ehdr ehdr)
 708{
 709	return ehdr.e_type == ET_EXEC || ehdr.e_type == ET_REL;
 
 
 
 
 
 
 710}
 711
 712int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name,
 713		 enum dso_binary_type type)
 714{
 715	GElf_Ehdr ehdr;
 716	Elf *elf;
 717	int fd;
 718
 719	if (dso__needs_decompress(dso)) {
 720		fd = dso__decompress_kmodule_fd(dso, name);
 721		if (fd < 0)
 722			return -1;
 723
 724		type = dso->symtab_type;
 725	} else {
 726		fd = open(name, O_RDONLY);
 727		if (fd < 0) {
 728			dso->load_errno = errno;
 729			return -1;
 730		}
 731	}
 732
 733	elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
 734	if (elf == NULL) {
 735		pr_debug("%s: cannot read %s ELF file.\n", __func__, name);
 736		dso->load_errno = DSO_LOAD_ERRNO__INVALID_ELF;
 737		goto out_close;
 738	}
 739
 740	if (gelf_getehdr(elf, &ehdr) == NULL) {
 741		dso->load_errno = DSO_LOAD_ERRNO__INVALID_ELF;
 742		pr_debug("%s: cannot get elf header.\n", __func__);
 743		goto out_elf_end;
 744	}
 745
 746	if (dso__swap_init(dso, ehdr.e_ident[EI_DATA])) {
 747		dso->load_errno = DSO_LOAD_ERRNO__INTERNAL_ERROR;
 748		goto out_elf_end;
 749	}
 750
 751	/* Always reject images with a mismatched build-id: */
 752	if (dso->has_build_id && !symbol_conf.ignore_vmlinux_buildid) {
 753		u8 build_id[BUILD_ID_SIZE];
 
 
 754
 755		if (elf_read_build_id(elf, build_id, BUILD_ID_SIZE) < 0) {
 756			dso->load_errno = DSO_LOAD_ERRNO__CANNOT_READ_BUILDID;
 
 757			goto out_elf_end;
 758		}
 759
 760		if (!dso__build_id_equal(dso, build_id)) {
 
 761			pr_debug("%s: build id mismatch for %s.\n", __func__, name);
 762			dso->load_errno = DSO_LOAD_ERRNO__MISMATCHING_BUILDID;
 763			goto out_elf_end;
 764		}
 765	}
 766
 767	ss->is_64_bit = (gelf_getclass(elf) == ELFCLASS64);
 768
 
 769	ss->symtab = elf_section_by_name(elf, &ehdr, &ss->symshdr, ".symtab",
 770			NULL);
 771	if (ss->symshdr.sh_type != SHT_SYMTAB)
 772		ss->symtab = NULL;
 773
 774	ss->dynsym_idx = 0;
 775	ss->dynsym = elf_section_by_name(elf, &ehdr, &ss->dynshdr, ".dynsym",
 776			&ss->dynsym_idx);
 777	if (ss->dynshdr.sh_type != SHT_DYNSYM)
 778		ss->dynsym = NULL;
 779
 780	ss->opdidx = 0;
 781	ss->opdsec = elf_section_by_name(elf, &ehdr, &ss->opdshdr, ".opd",
 782			&ss->opdidx);
 783	if (ss->opdshdr.sh_type != SHT_PROGBITS)
 784		ss->opdsec = NULL;
 785
 786	if (dso->kernel == DSO_TYPE_USER)
 787		ss->adjust_symbols = true;
 788	else
 789		ss->adjust_symbols = elf__needs_adjust_symbols(ehdr);
 790
 791	ss->name   = strdup(name);
 792	if (!ss->name) {
 793		dso->load_errno = errno;
 794		goto out_elf_end;
 795	}
 796
 797	ss->elf    = elf;
 798	ss->fd     = fd;
 799	ss->ehdr   = ehdr;
 800	ss->type   = type;
 801
 802	return 0;
 803
 804out_elf_end:
 805	elf_end(elf);
 806out_close:
 807	close(fd);
 808	return -1;
 809}
 810
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 811/**
 812 * ref_reloc_sym_not_found - has kernel relocation symbol been found.
 813 * @kmap: kernel maps and relocation reference symbol
 814 *
 815 * This function returns %true if we are dealing with the kernel maps and the
 816 * relocation reference symbol has not yet been found.  Otherwise %false is
 817 * returned.
 818 */
 819static bool ref_reloc_sym_not_found(struct kmap *kmap)
 820{
 821	return kmap && kmap->ref_reloc_sym && kmap->ref_reloc_sym->name &&
 822	       !kmap->ref_reloc_sym->unrelocated_addr;
 823}
 824
 825/**
 826 * ref_reloc - kernel relocation offset.
 827 * @kmap: kernel maps and relocation reference symbol
 828 *
 829 * This function returns the offset of kernel addresses as determined by using
 830 * the relocation reference symbol i.e. if the kernel has not been relocated
 831 * then the return value is zero.
 832 */
 833static u64 ref_reloc(struct kmap *kmap)
 834{
 835	if (kmap && kmap->ref_reloc_sym &&
 836	    kmap->ref_reloc_sym->unrelocated_addr)
 837		return kmap->ref_reloc_sym->addr -
 838		       kmap->ref_reloc_sym->unrelocated_addr;
 839	return 0;
 840}
 841
 842void __weak arch__sym_update(struct symbol *s __maybe_unused,
 843		GElf_Sym *sym __maybe_unused) { }
 844
 845static int dso__process_kernel_symbol(struct dso *dso, struct map *map,
 846				      GElf_Sym *sym, GElf_Shdr *shdr,
 847				      struct map_groups *kmaps, struct kmap *kmap,
 848				      struct dso **curr_dsop, struct map **curr_mapp,
 849				      const char *section_name,
 850				      bool adjust_kernel_syms, bool kmodule, bool *remap_kernel)
 
 851{
 852	struct dso *curr_dso = *curr_dsop;
 853	struct map *curr_map;
 854	char dso_name[PATH_MAX];
 855
 856	/* Adjust symbol to map to file offset */
 857	if (adjust_kernel_syms)
 858		sym->st_value -= shdr->sh_addr - shdr->sh_offset;
 859
 860	if (strcmp(section_name, (curr_dso->short_name + dso->short_name_len)) == 0)
 861		return 0;
 862
 863	if (strcmp(section_name, ".text") == 0) {
 864		/*
 865		 * The initial kernel mapping is based on
 866		 * kallsyms and identity maps.  Overwrite it to
 867		 * map to the kernel dso.
 868		 */
 869		if (*remap_kernel && dso->kernel) {
 870			*remap_kernel = false;
 871			map->start = shdr->sh_addr + ref_reloc(kmap);
 872			map->end = map->start + shdr->sh_size;
 873			map->pgoff = shdr->sh_offset;
 874			map->map_ip = map__map_ip;
 875			map->unmap_ip = map__unmap_ip;
 876			/* Ensure maps are correctly ordered */
 877			if (kmaps) {
 878				map__get(map);
 879				map_groups__remove(kmaps, map);
 880				map_groups__insert(kmaps, map);
 881				map__put(map);
 
 
 
 
 882			}
 883		}
 884
 885		/*
 886		 * The initial module mapping is based on
 887		 * /proc/modules mapped to offset zero.
 888		 * Overwrite it to map to the module dso.
 889		 */
 890		if (*remap_kernel && kmodule) {
 891			*remap_kernel = false;
 892			map->pgoff = shdr->sh_offset;
 893		}
 894
 895		*curr_mapp = map;
 896		*curr_dsop = dso;
 897		return 0;
 898	}
 899
 900	if (!kmap)
 901		return 0;
 902
 903	snprintf(dso_name, sizeof(dso_name), "%s%s", dso->short_name, section_name);
 
 
 
 
 
 
 
 
 
 
 
 904
 905	curr_map = map_groups__find_by_name(kmaps, dso_name);
 906	if (curr_map == NULL) {
 907		u64 start = sym->st_value;
 908
 909		if (kmodule)
 910			start += map->start + shdr->sh_offset;
 911
 912		curr_dso = dso__new(dso_name);
 913		if (curr_dso == NULL)
 914			return -1;
 915		curr_dso->kernel = dso->kernel;
 916		curr_dso->long_name = dso->long_name;
 917		curr_dso->long_name_len = dso->long_name_len;
 
 
 918		curr_map = map__new2(start, curr_dso);
 919		dso__put(curr_dso);
 920		if (curr_map == NULL)
 921			return -1;
 
 
 
 922
 923		if (adjust_kernel_syms) {
 924			curr_map->start  = shdr->sh_addr + ref_reloc(kmap);
 925			curr_map->end	 = curr_map->start + shdr->sh_size;
 926			curr_map->pgoff	 = shdr->sh_offset;
 927		} else {
 928			curr_map->map_ip = curr_map->unmap_ip = identity__map_ip;
 929		}
 930		curr_dso->symtab_type = dso->symtab_type;
 931		map_groups__insert(kmaps, curr_map);
 932		/*
 933		 * Add it before we drop the referece to curr_map, i.e. while
 934		 * we still are sure to have a reference to this DSO via
 935		 * *curr_map->dso.
 936		 */
 937		dsos__add(&map->groups->machine->dsos, curr_dso);
 938		/* kmaps already got it */
 939		map__put(curr_map);
 940		dso__set_loaded(curr_dso);
 941		*curr_mapp = curr_map;
 942		*curr_dsop = curr_dso;
 943	} else
 944		*curr_dsop = curr_map->dso;
 
 
 
 945
 946	return 0;
 947}
 948
 949int dso__load_sym(struct dso *dso, struct map *map, struct symsrc *syms_ss,
 950		  struct symsrc *runtime_ss, int kmodule)
 951{
 952	struct kmap *kmap = dso->kernel ? map__kmap(map) : NULL;
 953	struct map_groups *kmaps = kmap ? map__kmaps(map) : NULL;
 954	struct map *curr_map = map;
 955	struct dso *curr_dso = dso;
 956	Elf_Data *symstrs, *secstrs;
 957	uint32_t nr_syms;
 958	int err = -1;
 959	uint32_t idx;
 960	GElf_Ehdr ehdr;
 961	GElf_Shdr shdr;
 962	GElf_Shdr tshdr;
 963	Elf_Data *syms, *opddata = NULL;
 964	GElf_Sym sym;
 965	Elf_Scn *sec, *sec_strndx;
 966	Elf *elf;
 967	int nr = 0;
 968	bool remap_kernel = false, adjust_kernel_syms = false;
 
 969
 970	if (kmap && !kmaps)
 971		return -1;
 972
 973	dso->symtab_type = syms_ss->type;
 974	dso->is_64_bit = syms_ss->is_64_bit;
 975	dso->rel = syms_ss->ehdr.e_type == ET_REL;
 976
 977	/*
 978	 * Modules may already have symbols from kallsyms, but those symbols
 979	 * have the wrong values for the dso maps, so remove them.
 980	 */
 981	if (kmodule && syms_ss->symtab)
 982		symbols__delete(&dso->symbols);
 983
 984	if (!syms_ss->symtab) {
 985		/*
 986		 * If the vmlinux is stripped, fail so we will fall back
 987		 * to using kallsyms. The vmlinux runtime symbols aren't
 988		 * of much use.
 989		 */
 990		if (dso->kernel)
 991			goto out_elf_end;
 992
 993		syms_ss->symtab  = syms_ss->dynsym;
 994		syms_ss->symshdr = syms_ss->dynshdr;
 995	}
 996
 997	elf = syms_ss->elf;
 998	ehdr = syms_ss->ehdr;
 999	sec = syms_ss->symtab;
1000	shdr = syms_ss->symshdr;
 
 
 
 
 
1001
1002	if (elf_section_by_name(runtime_ss->elf, &runtime_ss->ehdr, &tshdr,
1003				".text", NULL))
1004		dso->text_offset = tshdr.sh_addr - tshdr.sh_offset;
 
 
1005
1006	if (runtime_ss->opdsec)
1007		opddata = elf_rawdata(runtime_ss->opdsec, NULL);
1008
1009	syms = elf_getdata(sec, NULL);
1010	if (syms == NULL)
1011		goto out_elf_end;
1012
1013	sec = elf_getscn(elf, shdr.sh_link);
1014	if (sec == NULL)
1015		goto out_elf_end;
1016
1017	symstrs = elf_getdata(sec, NULL);
1018	if (symstrs == NULL)
1019		goto out_elf_end;
1020
1021	sec_strndx = elf_getscn(runtime_ss->elf, runtime_ss->ehdr.e_shstrndx);
1022	if (sec_strndx == NULL)
1023		goto out_elf_end;
1024
1025	secstrs = elf_getdata(sec_strndx, NULL);
1026	if (secstrs == NULL)
 
 
 
 
 
 
 
 
1027		goto out_elf_end;
1028
1029	nr_syms = shdr.sh_size / shdr.sh_entsize;
1030
1031	memset(&sym, 0, sizeof(sym));
1032
1033	/*
1034	 * The kernel relocation symbol is needed in advance in order to adjust
1035	 * kernel maps correctly.
1036	 */
1037	if (ref_reloc_sym_not_found(kmap)) {
1038		elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
1039			const char *elf_name = elf_sym__name(&sym, symstrs);
1040
1041			if (strcmp(elf_name, kmap->ref_reloc_sym->name))
1042				continue;
1043			kmap->ref_reloc_sym->unrelocated_addr = sym.st_value;
1044			map->reloc = kmap->ref_reloc_sym->addr -
1045				     kmap->ref_reloc_sym->unrelocated_addr;
1046			break;
1047		}
1048	}
1049
1050	/*
1051	 * Handle any relocation of vdso necessary because older kernels
1052	 * attempted to prelink vdso to its virtual address.
1053	 */
1054	if (dso__is_vdso(dso))
1055		map->reloc = map->start - dso->text_offset;
1056
1057	dso->adjust_symbols = runtime_ss->adjust_symbols || ref_reloc(kmap);
1058	/*
1059	 * Initial kernel and module mappings do not map to the dso.
1060	 * Flag the fixups.
1061	 */
1062	if (dso->kernel || kmodule) {
1063		remap_kernel = true;
1064		adjust_kernel_syms = dso->adjust_symbols;
1065	}
 
 
 
 
 
1066	elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
1067		struct symbol *f;
1068		const char *elf_name = elf_sym__name(&sym, symstrs);
1069		char *demangled = NULL;
1070		int is_label = elf_sym__is_label(&sym);
1071		const char *section_name;
1072		bool used_opd = false;
1073
1074		if (!is_label && !elf_sym__filter(&sym))
1075			continue;
1076
1077		/* Reject ARM ELF "mapping symbols": these aren't unique and
1078		 * don't identify functions, so will confuse the profile
1079		 * output: */
1080		if (ehdr.e_machine == EM_ARM || ehdr.e_machine == EM_AARCH64) {
1081			if (elf_name[0] == '$' && strchr("adtx", elf_name[1])
1082			    && (elf_name[2] == '\0' || elf_name[2] == '.'))
1083				continue;
1084		}
1085
1086		if (runtime_ss->opdsec && sym.st_shndx == runtime_ss->opdidx) {
1087			u32 offset = sym.st_value - syms_ss->opdshdr.sh_addr;
1088			u64 *opd = opddata->d_buf + offset;
1089			sym.st_value = DSO__SWAP(dso, u64, *opd);
1090			sym.st_shndx = elf_addr_to_index(runtime_ss->elf,
1091					sym.st_value);
1092			used_opd = true;
1093		}
 
1094		/*
1095		 * When loading symbols in a data mapping, ABS symbols (which
1096		 * has a value of SHN_ABS in its st_shndx) failed at
1097		 * elf_getscn().  And it marks the loading as a failure so
1098		 * already loaded symbols cannot be fixed up.
1099		 *
1100		 * I'm not sure what should be done. Just ignore them for now.
1101		 * - Namhyung Kim
1102		 */
1103		if (sym.st_shndx == SHN_ABS)
1104			continue;
1105
1106		sec = elf_getscn(runtime_ss->elf, sym.st_shndx);
1107		if (!sec)
1108			goto out_elf_end;
1109
1110		gelf_getshdr(sec, &shdr);
1111
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1112		if (is_label && !elf_sec__filter(&shdr, secstrs))
1113			continue;
1114
1115		section_name = elf_sec__name(&shdr, secstrs);
1116
1117		/* On ARM, symbols for thumb functions have 1 added to
1118		 * the symbol address as a flag - remove it */
1119		if ((ehdr.e_machine == EM_ARM) &&
1120		    (GELF_ST_TYPE(sym.st_info) == STT_FUNC) &&
1121		    (sym.st_value & 1))
1122			--sym.st_value;
1123
1124		if (dso->kernel || kmodule) {
1125			if (dso__process_kernel_symbol(dso, map, &sym, &shdr, kmaps, kmap, &curr_dso, &curr_map,
1126						       section_name, adjust_kernel_syms, kmodule, &remap_kernel))
 
 
 
 
 
1127				goto out_elf_end;
1128		} else if ((used_opd && runtime_ss->adjust_symbols) ||
1129			   (!used_opd && syms_ss->adjust_symbols)) {
1130			pr_debug4("%s: adjusting symbol: st_value: %#" PRIx64 " "
1131				  "sh_addr: %#" PRIx64 " sh_offset: %#" PRIx64 "\n", __func__,
1132				  (u64)sym.st_value, (u64)shdr.sh_addr,
1133				  (u64)shdr.sh_offset);
1134			sym.st_value -= shdr.sh_addr - shdr.sh_offset;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1135		}
1136
1137		demangled = demangle_sym(dso, kmodule, elf_name);
1138		if (demangled != NULL)
1139			elf_name = demangled;
1140
1141		f = symbol__new(sym.st_value, sym.st_size,
1142				GELF_ST_BIND(sym.st_info),
1143				GELF_ST_TYPE(sym.st_info), elf_name);
1144		free(demangled);
1145		if (!f)
1146			goto out_elf_end;
1147
1148		arch__sym_update(f, &sym);
1149
1150		__symbols__insert(&curr_dso->symbols, f, dso->kernel);
1151		nr++;
1152	}
 
1153
1154	/*
1155	 * For misannotated, zeroed, ASM function sizes.
1156	 */
1157	if (nr > 0) {
1158		symbols__fixup_end(&dso->symbols);
1159		symbols__fixup_duplicate(&dso->symbols);
1160		if (kmap) {
1161			/*
1162			 * We need to fixup this here too because we create new
1163			 * maps here, for things like vsyscall sections.
1164			 */
1165			map_groups__fixup_end(kmaps);
1166		}
1167	}
1168	err = nr;
1169out_elf_end:
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1170	return err;
1171}
1172
1173static int elf_read_maps(Elf *elf, bool exe, mapfn_t mapfn, void *data)
1174{
1175	GElf_Phdr phdr;
1176	size_t i, phdrnum;
1177	int err;
1178	u64 sz;
1179
1180	if (elf_getphdrnum(elf, &phdrnum))
1181		return -1;
1182
1183	for (i = 0; i < phdrnum; i++) {
1184		if (gelf_getphdr(elf, i, &phdr) == NULL)
1185			return -1;
1186		if (phdr.p_type != PT_LOAD)
1187			continue;
1188		if (exe) {
1189			if (!(phdr.p_flags & PF_X))
1190				continue;
1191		} else {
1192			if (!(phdr.p_flags & PF_R))
1193				continue;
1194		}
1195		sz = min(phdr.p_memsz, phdr.p_filesz);
1196		if (!sz)
1197			continue;
1198		err = mapfn(phdr.p_vaddr, sz, phdr.p_offset, data);
1199		if (err)
1200			return err;
1201	}
1202	return 0;
1203}
1204
1205int file__read_maps(int fd, bool exe, mapfn_t mapfn, void *data,
1206		    bool *is_64_bit)
1207{
1208	int err;
1209	Elf *elf;
1210
1211	elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
1212	if (elf == NULL)
1213		return -1;
1214
1215	if (is_64_bit)
1216		*is_64_bit = (gelf_getclass(elf) == ELFCLASS64);
1217
1218	err = elf_read_maps(elf, exe, mapfn, data);
1219
1220	elf_end(elf);
1221	return err;
1222}
1223
1224enum dso_type dso__type_fd(int fd)
1225{
1226	enum dso_type dso_type = DSO__TYPE_UNKNOWN;
1227	GElf_Ehdr ehdr;
1228	Elf_Kind ek;
1229	Elf *elf;
1230
1231	elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
1232	if (elf == NULL)
1233		goto out;
1234
1235	ek = elf_kind(elf);
1236	if (ek != ELF_K_ELF)
1237		goto out_end;
1238
1239	if (gelf_getclass(elf) == ELFCLASS64) {
1240		dso_type = DSO__TYPE_64BIT;
1241		goto out_end;
1242	}
1243
1244	if (gelf_getehdr(elf, &ehdr) == NULL)
1245		goto out_end;
1246
1247	if (ehdr.e_machine == EM_X86_64)
1248		dso_type = DSO__TYPE_X32BIT;
1249	else
1250		dso_type = DSO__TYPE_32BIT;
1251out_end:
1252	elf_end(elf);
1253out:
1254	return dso_type;
1255}
1256
1257static int copy_bytes(int from, off_t from_offs, int to, off_t to_offs, u64 len)
1258{
1259	ssize_t r;
1260	size_t n;
1261	int err = -1;
1262	char *buf = malloc(page_size);
1263
1264	if (buf == NULL)
1265		return -1;
1266
1267	if (lseek(to, to_offs, SEEK_SET) != to_offs)
1268		goto out;
1269
1270	if (lseek(from, from_offs, SEEK_SET) != from_offs)
1271		goto out;
1272
1273	while (len) {
1274		n = page_size;
1275		if (len < n)
1276			n = len;
1277		/* Use read because mmap won't work on proc files */
1278		r = read(from, buf, n);
1279		if (r < 0)
1280			goto out;
1281		if (!r)
1282			break;
1283		n = r;
1284		r = write(to, buf, n);
1285		if (r < 0)
1286			goto out;
1287		if ((size_t)r != n)
1288			goto out;
1289		len -= n;
1290	}
1291
1292	err = 0;
1293out:
1294	free(buf);
1295	return err;
1296}
1297
1298struct kcore {
1299	int fd;
1300	int elfclass;
1301	Elf *elf;
1302	GElf_Ehdr ehdr;
1303};
1304
1305static int kcore__open(struct kcore *kcore, const char *filename)
1306{
1307	GElf_Ehdr *ehdr;
1308
1309	kcore->fd = open(filename, O_RDONLY);
1310	if (kcore->fd == -1)
1311		return -1;
1312
1313	kcore->elf = elf_begin(kcore->fd, ELF_C_READ, NULL);
1314	if (!kcore->elf)
1315		goto out_close;
1316
1317	kcore->elfclass = gelf_getclass(kcore->elf);
1318	if (kcore->elfclass == ELFCLASSNONE)
1319		goto out_end;
1320
1321	ehdr = gelf_getehdr(kcore->elf, &kcore->ehdr);
1322	if (!ehdr)
1323		goto out_end;
1324
1325	return 0;
1326
1327out_end:
1328	elf_end(kcore->elf);
1329out_close:
1330	close(kcore->fd);
1331	return -1;
1332}
1333
1334static int kcore__init(struct kcore *kcore, char *filename, int elfclass,
1335		       bool temp)
1336{
1337	kcore->elfclass = elfclass;
1338
1339	if (temp)
1340		kcore->fd = mkstemp(filename);
1341	else
1342		kcore->fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0400);
1343	if (kcore->fd == -1)
1344		return -1;
1345
1346	kcore->elf = elf_begin(kcore->fd, ELF_C_WRITE, NULL);
1347	if (!kcore->elf)
1348		goto out_close;
1349
1350	if (!gelf_newehdr(kcore->elf, elfclass))
1351		goto out_end;
1352
1353	memset(&kcore->ehdr, 0, sizeof(GElf_Ehdr));
1354
1355	return 0;
1356
1357out_end:
1358	elf_end(kcore->elf);
1359out_close:
1360	close(kcore->fd);
1361	unlink(filename);
1362	return -1;
1363}
1364
1365static void kcore__close(struct kcore *kcore)
1366{
1367	elf_end(kcore->elf);
1368	close(kcore->fd);
1369}
1370
1371static int kcore__copy_hdr(struct kcore *from, struct kcore *to, size_t count)
1372{
1373	GElf_Ehdr *ehdr = &to->ehdr;
1374	GElf_Ehdr *kehdr = &from->ehdr;
1375
1376	memcpy(ehdr->e_ident, kehdr->e_ident, EI_NIDENT);
1377	ehdr->e_type      = kehdr->e_type;
1378	ehdr->e_machine   = kehdr->e_machine;
1379	ehdr->e_version   = kehdr->e_version;
1380	ehdr->e_entry     = 0;
1381	ehdr->e_shoff     = 0;
1382	ehdr->e_flags     = kehdr->e_flags;
1383	ehdr->e_phnum     = count;
1384	ehdr->e_shentsize = 0;
1385	ehdr->e_shnum     = 0;
1386	ehdr->e_shstrndx  = 0;
1387
1388	if (from->elfclass == ELFCLASS32) {
1389		ehdr->e_phoff     = sizeof(Elf32_Ehdr);
1390		ehdr->e_ehsize    = sizeof(Elf32_Ehdr);
1391		ehdr->e_phentsize = sizeof(Elf32_Phdr);
1392	} else {
1393		ehdr->e_phoff     = sizeof(Elf64_Ehdr);
1394		ehdr->e_ehsize    = sizeof(Elf64_Ehdr);
1395		ehdr->e_phentsize = sizeof(Elf64_Phdr);
1396	}
1397
1398	if (!gelf_update_ehdr(to->elf, ehdr))
1399		return -1;
1400
1401	if (!gelf_newphdr(to->elf, count))
1402		return -1;
1403
1404	return 0;
1405}
1406
1407static int kcore__add_phdr(struct kcore *kcore, int idx, off_t offset,
1408			   u64 addr, u64 len)
1409{
1410	GElf_Phdr phdr = {
1411		.p_type		= PT_LOAD,
1412		.p_flags	= PF_R | PF_W | PF_X,
1413		.p_offset	= offset,
1414		.p_vaddr	= addr,
1415		.p_paddr	= 0,
1416		.p_filesz	= len,
1417		.p_memsz	= len,
1418		.p_align	= page_size,
1419	};
1420
1421	if (!gelf_update_phdr(kcore->elf, idx, &phdr))
1422		return -1;
1423
1424	return 0;
1425}
1426
1427static off_t kcore__write(struct kcore *kcore)
1428{
1429	return elf_update(kcore->elf, ELF_C_WRITE);
1430}
1431
1432struct phdr_data {
1433	off_t offset;
1434	off_t rel;
1435	u64 addr;
1436	u64 len;
1437	struct list_head node;
1438	struct phdr_data *remaps;
1439};
1440
1441struct sym_data {
1442	u64 addr;
1443	struct list_head node;
1444};
1445
1446struct kcore_copy_info {
1447	u64 stext;
1448	u64 etext;
1449	u64 first_symbol;
1450	u64 last_symbol;
1451	u64 first_module;
 
1452	u64 last_module_symbol;
1453	size_t phnum;
1454	struct list_head phdrs;
1455	struct list_head syms;
1456};
1457
1458#define kcore_copy__for_each_phdr(k, p) \
1459	list_for_each_entry((p), &(k)->phdrs, node)
1460
1461static struct phdr_data *phdr_data__new(u64 addr, u64 len, off_t offset)
1462{
1463	struct phdr_data *p = zalloc(sizeof(*p));
1464
1465	if (p) {
1466		p->addr   = addr;
1467		p->len    = len;
1468		p->offset = offset;
1469	}
1470
1471	return p;
1472}
1473
1474static struct phdr_data *kcore_copy_info__addnew(struct kcore_copy_info *kci,
1475						 u64 addr, u64 len,
1476						 off_t offset)
1477{
1478	struct phdr_data *p = phdr_data__new(addr, len, offset);
1479
1480	if (p)
1481		list_add_tail(&p->node, &kci->phdrs);
1482
1483	return p;
1484}
1485
1486static void kcore_copy__free_phdrs(struct kcore_copy_info *kci)
1487{
1488	struct phdr_data *p, *tmp;
1489
1490	list_for_each_entry_safe(p, tmp, &kci->phdrs, node) {
1491		list_del_init(&p->node);
1492		free(p);
1493	}
1494}
1495
1496static struct sym_data *kcore_copy__new_sym(struct kcore_copy_info *kci,
1497					    u64 addr)
1498{
1499	struct sym_data *s = zalloc(sizeof(*s));
1500
1501	if (s) {
1502		s->addr = addr;
1503		list_add_tail(&s->node, &kci->syms);
1504	}
1505
1506	return s;
1507}
1508
1509static void kcore_copy__free_syms(struct kcore_copy_info *kci)
1510{
1511	struct sym_data *s, *tmp;
1512
1513	list_for_each_entry_safe(s, tmp, &kci->syms, node) {
1514		list_del_init(&s->node);
1515		free(s);
1516	}
1517}
1518
1519static int kcore_copy__process_kallsyms(void *arg, const char *name, char type,
1520					u64 start)
1521{
1522	struct kcore_copy_info *kci = arg;
1523
1524	if (!kallsyms__is_function(type))
1525		return 0;
1526
1527	if (strchr(name, '[')) {
 
 
1528		if (start > kci->last_module_symbol)
1529			kci->last_module_symbol = start;
1530		return 0;
1531	}
1532
1533	if (!kci->first_symbol || start < kci->first_symbol)
1534		kci->first_symbol = start;
1535
1536	if (!kci->last_symbol || start > kci->last_symbol)
1537		kci->last_symbol = start;
1538
1539	if (!strcmp(name, "_stext")) {
1540		kci->stext = start;
1541		return 0;
1542	}
1543
1544	if (!strcmp(name, "_etext")) {
1545		kci->etext = start;
1546		return 0;
1547	}
1548
1549	if (is_entry_trampoline(name) && !kcore_copy__new_sym(kci, start))
1550		return -1;
1551
1552	return 0;
1553}
1554
1555static int kcore_copy__parse_kallsyms(struct kcore_copy_info *kci,
1556				      const char *dir)
1557{
1558	char kallsyms_filename[PATH_MAX];
1559
1560	scnprintf(kallsyms_filename, PATH_MAX, "%s/kallsyms", dir);
1561
1562	if (symbol__restricted_filename(kallsyms_filename, "/proc/kallsyms"))
1563		return -1;
1564
1565	if (kallsyms__parse(kallsyms_filename, kci,
1566			    kcore_copy__process_kallsyms) < 0)
1567		return -1;
1568
1569	return 0;
1570}
1571
1572static int kcore_copy__process_modules(void *arg,
1573				       const char *name __maybe_unused,
1574				       u64 start, u64 size __maybe_unused)
1575{
1576	struct kcore_copy_info *kci = arg;
1577
1578	if (!kci->first_module || start < kci->first_module)
1579		kci->first_module = start;
1580
1581	return 0;
1582}
1583
1584static int kcore_copy__parse_modules(struct kcore_copy_info *kci,
1585				     const char *dir)
1586{
1587	char modules_filename[PATH_MAX];
1588
1589	scnprintf(modules_filename, PATH_MAX, "%s/modules", dir);
1590
1591	if (symbol__restricted_filename(modules_filename, "/proc/modules"))
1592		return -1;
1593
1594	if (modules__parse(modules_filename, kci,
1595			   kcore_copy__process_modules) < 0)
1596		return -1;
1597
1598	return 0;
1599}
1600
1601static int kcore_copy__map(struct kcore_copy_info *kci, u64 start, u64 end,
1602			   u64 pgoff, u64 s, u64 e)
1603{
1604	u64 len, offset;
1605
1606	if (s < start || s >= end)
1607		return 0;
1608
1609	offset = (s - start) + pgoff;
1610	len = e < end ? e - s : end - s;
1611
1612	return kcore_copy_info__addnew(kci, s, len, offset) ? 0 : -1;
1613}
1614
1615static int kcore_copy__read_map(u64 start, u64 len, u64 pgoff, void *data)
1616{
1617	struct kcore_copy_info *kci = data;
1618	u64 end = start + len;
1619	struct sym_data *sdat;
1620
1621	if (kcore_copy__map(kci, start, end, pgoff, kci->stext, kci->etext))
1622		return -1;
1623
1624	if (kcore_copy__map(kci, start, end, pgoff, kci->first_module,
1625			    kci->last_module_symbol))
1626		return -1;
1627
1628	list_for_each_entry(sdat, &kci->syms, node) {
1629		u64 s = round_down(sdat->addr, page_size);
1630
1631		if (kcore_copy__map(kci, start, end, pgoff, s, s + len))
1632			return -1;
1633	}
1634
1635	return 0;
1636}
1637
1638static int kcore_copy__read_maps(struct kcore_copy_info *kci, Elf *elf)
1639{
1640	if (elf_read_maps(elf, true, kcore_copy__read_map, kci) < 0)
1641		return -1;
1642
1643	return 0;
1644}
1645
1646static void kcore_copy__find_remaps(struct kcore_copy_info *kci)
1647{
1648	struct phdr_data *p, *k = NULL;
1649	u64 kend;
1650
1651	if (!kci->stext)
1652		return;
1653
1654	/* Find phdr that corresponds to the kernel map (contains stext) */
1655	kcore_copy__for_each_phdr(kci, p) {
1656		u64 pend = p->addr + p->len - 1;
1657
1658		if (p->addr <= kci->stext && pend >= kci->stext) {
1659			k = p;
1660			break;
1661		}
1662	}
1663
1664	if (!k)
1665		return;
1666
1667	kend = k->offset + k->len;
1668
1669	/* Find phdrs that remap the kernel */
1670	kcore_copy__for_each_phdr(kci, p) {
1671		u64 pend = p->offset + p->len;
1672
1673		if (p == k)
1674			continue;
1675
1676		if (p->offset >= k->offset && pend <= kend)
1677			p->remaps = k;
1678	}
1679}
1680
1681static void kcore_copy__layout(struct kcore_copy_info *kci)
1682{
1683	struct phdr_data *p;
1684	off_t rel = 0;
1685
1686	kcore_copy__find_remaps(kci);
1687
1688	kcore_copy__for_each_phdr(kci, p) {
1689		if (!p->remaps) {
1690			p->rel = rel;
1691			rel += p->len;
1692		}
1693		kci->phnum += 1;
1694	}
1695
1696	kcore_copy__for_each_phdr(kci, p) {
1697		struct phdr_data *k = p->remaps;
1698
1699		if (k)
1700			p->rel = p->offset - k->offset + k->rel;
1701	}
1702}
1703
1704static int kcore_copy__calc_maps(struct kcore_copy_info *kci, const char *dir,
1705				 Elf *elf)
1706{
1707	if (kcore_copy__parse_kallsyms(kci, dir))
1708		return -1;
1709
1710	if (kcore_copy__parse_modules(kci, dir))
1711		return -1;
1712
1713	if (kci->stext)
1714		kci->stext = round_down(kci->stext, page_size);
1715	else
1716		kci->stext = round_down(kci->first_symbol, page_size);
1717
1718	if (kci->etext) {
1719		kci->etext = round_up(kci->etext, page_size);
1720	} else if (kci->last_symbol) {
1721		kci->etext = round_up(kci->last_symbol, page_size);
1722		kci->etext += page_size;
1723	}
1724
 
 
 
 
1725	kci->first_module = round_down(kci->first_module, page_size);
1726
1727	if (kci->last_module_symbol) {
1728		kci->last_module_symbol = round_up(kci->last_module_symbol,
1729						   page_size);
1730		kci->last_module_symbol += page_size;
1731	}
1732
1733	if (!kci->stext || !kci->etext)
1734		return -1;
1735
1736	if (kci->first_module && !kci->last_module_symbol)
1737		return -1;
1738
1739	if (kcore_copy__read_maps(kci, elf))
1740		return -1;
1741
1742	kcore_copy__layout(kci);
1743
1744	return 0;
1745}
1746
1747static int kcore_copy__copy_file(const char *from_dir, const char *to_dir,
1748				 const char *name)
1749{
1750	char from_filename[PATH_MAX];
1751	char to_filename[PATH_MAX];
1752
1753	scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
1754	scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
1755
1756	return copyfile_mode(from_filename, to_filename, 0400);
1757}
1758
1759static int kcore_copy__unlink(const char *dir, const char *name)
1760{
1761	char filename[PATH_MAX];
1762
1763	scnprintf(filename, PATH_MAX, "%s/%s", dir, name);
1764
1765	return unlink(filename);
1766}
1767
1768static int kcore_copy__compare_fds(int from, int to)
1769{
1770	char *buf_from;
1771	char *buf_to;
1772	ssize_t ret;
1773	size_t len;
1774	int err = -1;
1775
1776	buf_from = malloc(page_size);
1777	buf_to = malloc(page_size);
1778	if (!buf_from || !buf_to)
1779		goto out;
1780
1781	while (1) {
1782		/* Use read because mmap won't work on proc files */
1783		ret = read(from, buf_from, page_size);
1784		if (ret < 0)
1785			goto out;
1786
1787		if (!ret)
1788			break;
1789
1790		len = ret;
1791
1792		if (readn(to, buf_to, len) != (int)len)
1793			goto out;
1794
1795		if (memcmp(buf_from, buf_to, len))
1796			goto out;
1797	}
1798
1799	err = 0;
1800out:
1801	free(buf_to);
1802	free(buf_from);
1803	return err;
1804}
1805
1806static int kcore_copy__compare_files(const char *from_filename,
1807				     const char *to_filename)
1808{
1809	int from, to, err = -1;
1810
1811	from = open(from_filename, O_RDONLY);
1812	if (from < 0)
1813		return -1;
1814
1815	to = open(to_filename, O_RDONLY);
1816	if (to < 0)
1817		goto out_close_from;
1818
1819	err = kcore_copy__compare_fds(from, to);
1820
1821	close(to);
1822out_close_from:
1823	close(from);
1824	return err;
1825}
1826
1827static int kcore_copy__compare_file(const char *from_dir, const char *to_dir,
1828				    const char *name)
1829{
1830	char from_filename[PATH_MAX];
1831	char to_filename[PATH_MAX];
1832
1833	scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
1834	scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
1835
1836	return kcore_copy__compare_files(from_filename, to_filename);
1837}
1838
1839/**
1840 * kcore_copy - copy kallsyms, modules and kcore from one directory to another.
1841 * @from_dir: from directory
1842 * @to_dir: to directory
1843 *
1844 * This function copies kallsyms, modules and kcore files from one directory to
1845 * another.  kallsyms and modules are copied entirely.  Only code segments are
1846 * copied from kcore.  It is assumed that two segments suffice: one for the
1847 * kernel proper and one for all the modules.  The code segments are determined
1848 * from kallsyms and modules files.  The kernel map starts at _stext or the
1849 * lowest function symbol, and ends at _etext or the highest function symbol.
1850 * The module map starts at the lowest module address and ends at the highest
1851 * module symbol.  Start addresses are rounded down to the nearest page.  End
1852 * addresses are rounded up to the nearest page.  An extra page is added to the
1853 * highest kernel symbol and highest module symbol to, hopefully, encompass that
1854 * symbol too.  Because it contains only code sections, the resulting kcore is
1855 * unusual.  One significant peculiarity is that the mapping (start -> pgoff)
1856 * is not the same for the kernel map and the modules map.  That happens because
1857 * the data is copied adjacently whereas the original kcore has gaps.  Finally,
1858 * kallsyms and modules files are compared with their copies to check that
1859 * modules have not been loaded or unloaded while the copies were taking place.
1860 *
1861 * Return: %0 on success, %-1 on failure.
1862 */
1863int kcore_copy(const char *from_dir, const char *to_dir)
1864{
1865	struct kcore kcore;
1866	struct kcore extract;
1867	int idx = 0, err = -1;
1868	off_t offset, sz;
1869	struct kcore_copy_info kci = { .stext = 0, };
1870	char kcore_filename[PATH_MAX];
1871	char extract_filename[PATH_MAX];
1872	struct phdr_data *p;
1873
1874	INIT_LIST_HEAD(&kci.phdrs);
1875	INIT_LIST_HEAD(&kci.syms);
1876
1877	if (kcore_copy__copy_file(from_dir, to_dir, "kallsyms"))
1878		return -1;
1879
1880	if (kcore_copy__copy_file(from_dir, to_dir, "modules"))
1881		goto out_unlink_kallsyms;
1882
1883	scnprintf(kcore_filename, PATH_MAX, "%s/kcore", from_dir);
1884	scnprintf(extract_filename, PATH_MAX, "%s/kcore", to_dir);
1885
1886	if (kcore__open(&kcore, kcore_filename))
1887		goto out_unlink_modules;
1888
1889	if (kcore_copy__calc_maps(&kci, from_dir, kcore.elf))
1890		goto out_kcore_close;
1891
1892	if (kcore__init(&extract, extract_filename, kcore.elfclass, false))
1893		goto out_kcore_close;
1894
1895	if (kcore__copy_hdr(&kcore, &extract, kci.phnum))
1896		goto out_extract_close;
1897
1898	offset = gelf_fsize(extract.elf, ELF_T_EHDR, 1, EV_CURRENT) +
1899		 gelf_fsize(extract.elf, ELF_T_PHDR, kci.phnum, EV_CURRENT);
1900	offset = round_up(offset, page_size);
1901
1902	kcore_copy__for_each_phdr(&kci, p) {
1903		off_t offs = p->rel + offset;
1904
1905		if (kcore__add_phdr(&extract, idx++, offs, p->addr, p->len))
1906			goto out_extract_close;
1907	}
1908
1909	sz = kcore__write(&extract);
1910	if (sz < 0 || sz > offset)
1911		goto out_extract_close;
1912
1913	kcore_copy__for_each_phdr(&kci, p) {
1914		off_t offs = p->rel + offset;
1915
1916		if (p->remaps)
1917			continue;
1918		if (copy_bytes(kcore.fd, p->offset, extract.fd, offs, p->len))
1919			goto out_extract_close;
1920	}
1921
1922	if (kcore_copy__compare_file(from_dir, to_dir, "modules"))
1923		goto out_extract_close;
1924
1925	if (kcore_copy__compare_file(from_dir, to_dir, "kallsyms"))
1926		goto out_extract_close;
1927
1928	err = 0;
1929
1930out_extract_close:
1931	kcore__close(&extract);
1932	if (err)
1933		unlink(extract_filename);
1934out_kcore_close:
1935	kcore__close(&kcore);
1936out_unlink_modules:
1937	if (err)
1938		kcore_copy__unlink(to_dir, "modules");
1939out_unlink_kallsyms:
1940	if (err)
1941		kcore_copy__unlink(to_dir, "kallsyms");
1942
1943	kcore_copy__free_phdrs(&kci);
1944	kcore_copy__free_syms(&kci);
1945
1946	return err;
1947}
1948
1949int kcore_extract__create(struct kcore_extract *kce)
1950{
1951	struct kcore kcore;
1952	struct kcore extract;
1953	size_t count = 1;
1954	int idx = 0, err = -1;
1955	off_t offset = page_size, sz;
1956
1957	if (kcore__open(&kcore, kce->kcore_filename))
1958		return -1;
1959
1960	strcpy(kce->extract_filename, PERF_KCORE_EXTRACT);
1961	if (kcore__init(&extract, kce->extract_filename, kcore.elfclass, true))
1962		goto out_kcore_close;
1963
1964	if (kcore__copy_hdr(&kcore, &extract, count))
1965		goto out_extract_close;
1966
1967	if (kcore__add_phdr(&extract, idx, offset, kce->addr, kce->len))
1968		goto out_extract_close;
1969
1970	sz = kcore__write(&extract);
1971	if (sz < 0 || sz > offset)
1972		goto out_extract_close;
1973
1974	if (copy_bytes(kcore.fd, kce->offs, extract.fd, offset, kce->len))
1975		goto out_extract_close;
1976
1977	err = 0;
1978
1979out_extract_close:
1980	kcore__close(&extract);
1981	if (err)
1982		unlink(kce->extract_filename);
1983out_kcore_close:
1984	kcore__close(&kcore);
1985
1986	return err;
1987}
1988
1989void kcore_extract__delete(struct kcore_extract *kce)
1990{
1991	unlink(kce->extract_filename);
1992}
1993
1994#ifdef HAVE_GELF_GETNOTE_SUPPORT
1995
1996static void sdt_adjust_loc(struct sdt_note *tmp, GElf_Addr base_off)
1997{
1998	if (!base_off)
1999		return;
2000
2001	if (tmp->bit32)
2002		tmp->addr.a32[SDT_NOTE_IDX_LOC] =
2003			tmp->addr.a32[SDT_NOTE_IDX_LOC] + base_off -
2004			tmp->addr.a32[SDT_NOTE_IDX_BASE];
2005	else
2006		tmp->addr.a64[SDT_NOTE_IDX_LOC] =
2007			tmp->addr.a64[SDT_NOTE_IDX_LOC] + base_off -
2008			tmp->addr.a64[SDT_NOTE_IDX_BASE];
2009}
2010
2011static void sdt_adjust_refctr(struct sdt_note *tmp, GElf_Addr base_addr,
2012			      GElf_Addr base_off)
2013{
2014	if (!base_off)
2015		return;
2016
2017	if (tmp->bit32 && tmp->addr.a32[SDT_NOTE_IDX_REFCTR])
2018		tmp->addr.a32[SDT_NOTE_IDX_REFCTR] -= (base_addr - base_off);
2019	else if (tmp->addr.a64[SDT_NOTE_IDX_REFCTR])
2020		tmp->addr.a64[SDT_NOTE_IDX_REFCTR] -= (base_addr - base_off);
2021}
2022
2023/**
2024 * populate_sdt_note : Parse raw data and identify SDT note
2025 * @elf: elf of the opened file
2026 * @data: raw data of a section with description offset applied
2027 * @len: note description size
2028 * @type: type of the note
2029 * @sdt_notes: List to add the SDT note
2030 *
2031 * Responsible for parsing the @data in section .note.stapsdt in @elf and
2032 * if its an SDT note, it appends to @sdt_notes list.
2033 */
2034static int populate_sdt_note(Elf **elf, const char *data, size_t len,
2035			     struct list_head *sdt_notes)
2036{
2037	const char *provider, *name, *args;
2038	struct sdt_note *tmp = NULL;
2039	GElf_Ehdr ehdr;
2040	GElf_Shdr shdr;
2041	int ret = -EINVAL;
2042
2043	union {
2044		Elf64_Addr a64[NR_ADDR];
2045		Elf32_Addr a32[NR_ADDR];
2046	} buf;
2047
2048	Elf_Data dst = {
2049		.d_buf = &buf, .d_type = ELF_T_ADDR, .d_version = EV_CURRENT,
2050		.d_size = gelf_fsize((*elf), ELF_T_ADDR, NR_ADDR, EV_CURRENT),
2051		.d_off = 0, .d_align = 0
2052	};
2053	Elf_Data src = {
2054		.d_buf = (void *) data, .d_type = ELF_T_ADDR,
2055		.d_version = EV_CURRENT, .d_size = dst.d_size, .d_off = 0,
2056		.d_align = 0
2057	};
2058
2059	tmp = (struct sdt_note *)calloc(1, sizeof(struct sdt_note));
2060	if (!tmp) {
2061		ret = -ENOMEM;
2062		goto out_err;
2063	}
2064
2065	INIT_LIST_HEAD(&tmp->note_list);
2066
2067	if (len < dst.d_size + 3)
2068		goto out_free_note;
2069
2070	/* Translation from file representation to memory representation */
2071	if (gelf_xlatetom(*elf, &dst, &src,
2072			  elf_getident(*elf, NULL)[EI_DATA]) == NULL) {
2073		pr_err("gelf_xlatetom : %s\n", elf_errmsg(-1));
2074		goto out_free_note;
2075	}
2076
2077	/* Populate the fields of sdt_note */
2078	provider = data + dst.d_size;
2079
2080	name = (const char *)memchr(provider, '\0', data + len - provider);
2081	if (name++ == NULL)
2082		goto out_free_note;
2083
2084	tmp->provider = strdup(provider);
2085	if (!tmp->provider) {
2086		ret = -ENOMEM;
2087		goto out_free_note;
2088	}
2089	tmp->name = strdup(name);
2090	if (!tmp->name) {
2091		ret = -ENOMEM;
2092		goto out_free_prov;
2093	}
2094
2095	args = memchr(name, '\0', data + len - name);
2096
2097	/*
2098	 * There is no argument if:
2099	 * - We reached the end of the note;
2100	 * - There is not enough room to hold a potential string;
2101	 * - The argument string is empty or just contains ':'.
2102	 */
2103	if (args == NULL || data + len - args < 2 ||
2104		args[1] == ':' || args[1] == '\0')
2105		tmp->args = NULL;
2106	else {
2107		tmp->args = strdup(++args);
2108		if (!tmp->args) {
2109			ret = -ENOMEM;
2110			goto out_free_name;
2111		}
2112	}
2113
2114	if (gelf_getclass(*elf) == ELFCLASS32) {
2115		memcpy(&tmp->addr, &buf, 3 * sizeof(Elf32_Addr));
2116		tmp->bit32 = true;
2117	} else {
2118		memcpy(&tmp->addr, &buf, 3 * sizeof(Elf64_Addr));
2119		tmp->bit32 = false;
2120	}
2121
2122	if (!gelf_getehdr(*elf, &ehdr)) {
2123		pr_debug("%s : cannot get elf header.\n", __func__);
2124		ret = -EBADF;
2125		goto out_free_args;
2126	}
2127
2128	/* Adjust the prelink effect :
2129	 * Find out the .stapsdt.base section.
2130	 * This scn will help us to handle prelinking (if present).
2131	 * Compare the retrieved file offset of the base section with the
2132	 * base address in the description of the SDT note. If its different,
2133	 * then accordingly, adjust the note location.
2134	 */
2135	if (elf_section_by_name(*elf, &ehdr, &shdr, SDT_BASE_SCN, NULL))
2136		sdt_adjust_loc(tmp, shdr.sh_offset);
2137
2138	/* Adjust reference counter offset */
2139	if (elf_section_by_name(*elf, &ehdr, &shdr, SDT_PROBES_SCN, NULL))
2140		sdt_adjust_refctr(tmp, shdr.sh_addr, shdr.sh_offset);
2141
2142	list_add_tail(&tmp->note_list, sdt_notes);
2143	return 0;
2144
2145out_free_args:
2146	zfree(&tmp->args);
2147out_free_name:
2148	zfree(&tmp->name);
2149out_free_prov:
2150	zfree(&tmp->provider);
2151out_free_note:
2152	free(tmp);
2153out_err:
2154	return ret;
2155}
2156
2157/**
2158 * construct_sdt_notes_list : constructs a list of SDT notes
2159 * @elf : elf to look into
2160 * @sdt_notes : empty list_head
2161 *
2162 * Scans the sections in 'elf' for the section
2163 * .note.stapsdt. It, then calls populate_sdt_note to find
2164 * out the SDT events and populates the 'sdt_notes'.
2165 */
2166static int construct_sdt_notes_list(Elf *elf, struct list_head *sdt_notes)
2167{
2168	GElf_Ehdr ehdr;
2169	Elf_Scn *scn = NULL;
2170	Elf_Data *data;
2171	GElf_Shdr shdr;
2172	size_t shstrndx, next;
2173	GElf_Nhdr nhdr;
2174	size_t name_off, desc_off, offset;
2175	int ret = 0;
2176
2177	if (gelf_getehdr(elf, &ehdr) == NULL) {
2178		ret = -EBADF;
2179		goto out_ret;
2180	}
2181	if (elf_getshdrstrndx(elf, &shstrndx) != 0) {
2182		ret = -EBADF;
2183		goto out_ret;
2184	}
2185
2186	/* Look for the required section */
2187	scn = elf_section_by_name(elf, &ehdr, &shdr, SDT_NOTE_SCN, NULL);
2188	if (!scn) {
2189		ret = -ENOENT;
2190		goto out_ret;
2191	}
2192
2193	if ((shdr.sh_type != SHT_NOTE) || (shdr.sh_flags & SHF_ALLOC)) {
2194		ret = -ENOENT;
2195		goto out_ret;
2196	}
2197
2198	data = elf_getdata(scn, NULL);
2199
2200	/* Get the SDT notes */
2201	for (offset = 0; (next = gelf_getnote(data, offset, &nhdr, &name_off,
2202					      &desc_off)) > 0; offset = next) {
2203		if (nhdr.n_namesz == sizeof(SDT_NOTE_NAME) &&
2204		    !memcmp(data->d_buf + name_off, SDT_NOTE_NAME,
2205			    sizeof(SDT_NOTE_NAME))) {
2206			/* Check the type of the note */
2207			if (nhdr.n_type != SDT_NOTE_TYPE)
2208				goto out_ret;
2209
2210			ret = populate_sdt_note(&elf, ((data->d_buf) + desc_off),
2211						nhdr.n_descsz, sdt_notes);
2212			if (ret < 0)
2213				goto out_ret;
2214		}
2215	}
2216	if (list_empty(sdt_notes))
2217		ret = -ENOENT;
2218
2219out_ret:
2220	return ret;
2221}
2222
2223/**
2224 * get_sdt_note_list : Wrapper to construct a list of sdt notes
2225 * @head : empty list_head
2226 * @target : file to find SDT notes from
2227 *
2228 * This opens the file, initializes
2229 * the ELF and then calls construct_sdt_notes_list.
2230 */
2231int get_sdt_note_list(struct list_head *head, const char *target)
2232{
2233	Elf *elf;
2234	int fd, ret;
2235
2236	fd = open(target, O_RDONLY);
2237	if (fd < 0)
2238		return -EBADF;
2239
2240	elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
2241	if (!elf) {
2242		ret = -EBADF;
2243		goto out_close;
2244	}
2245	ret = construct_sdt_notes_list(elf, head);
2246	elf_end(elf);
2247out_close:
2248	close(fd);
2249	return ret;
2250}
2251
2252/**
2253 * cleanup_sdt_note_list : free the sdt notes' list
2254 * @sdt_notes: sdt notes' list
2255 *
2256 * Free up the SDT notes in @sdt_notes.
2257 * Returns the number of SDT notes free'd.
2258 */
2259int cleanup_sdt_note_list(struct list_head *sdt_notes)
2260{
2261	struct sdt_note *tmp, *pos;
2262	int nr_free = 0;
2263
2264	list_for_each_entry_safe(pos, tmp, sdt_notes, note_list) {
2265		list_del_init(&pos->note_list);
 
2266		zfree(&pos->name);
2267		zfree(&pos->provider);
2268		free(pos);
2269		nr_free++;
2270	}
2271	return nr_free;
2272}
2273
2274/**
2275 * sdt_notes__get_count: Counts the number of sdt events
2276 * @start: list_head to sdt_notes list
2277 *
2278 * Returns the number of SDT notes in a list
2279 */
2280int sdt_notes__get_count(struct list_head *start)
2281{
2282	struct sdt_note *sdt_ptr;
2283	int count = 0;
2284
2285	list_for_each_entry(sdt_ptr, start, note_list)
2286		count++;
2287	return count;
2288}
2289#endif
2290
2291void symbol__elf_init(void)
2292{
2293	elf_version(EV_CURRENT);
2294}