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  1/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
  2
  3/*
  4 * Internal libbpf helpers.
  5 *
  6 * Copyright (c) 2019 Facebook
  7 */
  8
  9#ifndef __LIBBPF_LIBBPF_INTERNAL_H
 10#define __LIBBPF_LIBBPF_INTERNAL_H
 11
 12#include <stdlib.h>
 13#include <limits.h>
 14#include <errno.h>
 15#include <linux/err.h>
 16#include <fcntl.h>
 17#include <unistd.h>
 18#include <libelf.h>
 19#include "relo_core.h"
 20
 21/* make sure libbpf doesn't use kernel-only integer typedefs */
 22#pragma GCC poison u8 u16 u32 u64 s8 s16 s32 s64
 23
 24/* prevent accidental re-addition of reallocarray() */
 25#pragma GCC poison reallocarray
 26
 27#include "libbpf.h"
 28#include "btf.h"
 29
 30#ifndef EM_BPF
 31#define EM_BPF 247
 32#endif
 33
 34#ifndef R_BPF_64_64
 35#define R_BPF_64_64 1
 36#endif
 37#ifndef R_BPF_64_ABS64
 38#define R_BPF_64_ABS64 2
 39#endif
 40#ifndef R_BPF_64_ABS32
 41#define R_BPF_64_ABS32 3
 42#endif
 43#ifndef R_BPF_64_32
 44#define R_BPF_64_32 10
 45#endif
 46
 47#ifndef SHT_LLVM_ADDRSIG
 48#define SHT_LLVM_ADDRSIG 0x6FFF4C03
 49#endif
 50
 51/* if libelf is old and doesn't support mmap(), fall back to read() */
 52#ifndef ELF_C_READ_MMAP
 53#define ELF_C_READ_MMAP ELF_C_READ
 54#endif
 55
 56/* Older libelf all end up in this expression, for both 32 and 64 bit */
 57#ifndef ELF64_ST_VISIBILITY
 58#define ELF64_ST_VISIBILITY(o) ((o) & 0x03)
 59#endif
 60
 61#define BTF_INFO_ENC(kind, kind_flag, vlen) \
 62	((!!(kind_flag) << 31) | ((kind) << 24) | ((vlen) & BTF_MAX_VLEN))
 63#define BTF_TYPE_ENC(name, info, size_or_type) (name), (info), (size_or_type)
 64#define BTF_INT_ENC(encoding, bits_offset, nr_bits) \
 65	((encoding) << 24 | (bits_offset) << 16 | (nr_bits))
 66#define BTF_TYPE_INT_ENC(name, encoding, bits_offset, bits, sz) \
 67	BTF_TYPE_ENC(name, BTF_INFO_ENC(BTF_KIND_INT, 0, 0), sz), \
 68	BTF_INT_ENC(encoding, bits_offset, bits)
 69#define BTF_MEMBER_ENC(name, type, bits_offset) (name), (type), (bits_offset)
 70#define BTF_PARAM_ENC(name, type) (name), (type)
 71#define BTF_VAR_SECINFO_ENC(type, offset, size) (type), (offset), (size)
 72#define BTF_TYPE_FLOAT_ENC(name, sz) \
 73	BTF_TYPE_ENC(name, BTF_INFO_ENC(BTF_KIND_FLOAT, 0, 0), sz)
 74#define BTF_TYPE_DECL_TAG_ENC(value, type, component_idx) \
 75	BTF_TYPE_ENC(value, BTF_INFO_ENC(BTF_KIND_DECL_TAG, 0, 0), type), (component_idx)
 76#define BTF_TYPE_TYPE_TAG_ENC(value, type) \
 77	BTF_TYPE_ENC(value, BTF_INFO_ENC(BTF_KIND_TYPE_TAG, 0, 0), type)
 78
 79#ifndef likely
 80#define likely(x) __builtin_expect(!!(x), 1)
 81#endif
 82#ifndef unlikely
 83#define unlikely(x) __builtin_expect(!!(x), 0)
 84#endif
 85#ifndef min
 86# define min(x, y) ((x) < (y) ? (x) : (y))
 87#endif
 88#ifndef max
 89# define max(x, y) ((x) < (y) ? (y) : (x))
 90#endif
 91#ifndef offsetofend
 92# define offsetofend(TYPE, FIELD) \
 93	(offsetof(TYPE, FIELD) + sizeof(((TYPE *)0)->FIELD))
 94#endif
 95#ifndef __alias
 96#define __alias(symbol) __attribute__((alias(#symbol)))
 97#endif
 98
 99/* Check whether a string `str` has prefix `pfx`, regardless if `pfx` is
100 * a string literal known at compilation time or char * pointer known only at
101 * runtime.
102 */
103#define str_has_pfx(str, pfx) \
104	(strncmp(str, pfx, __builtin_constant_p(pfx) ? sizeof(pfx) - 1 : strlen(pfx)) == 0)
105
106/* suffix check */
107static inline bool str_has_sfx(const char *str, const char *sfx)
108{
109	size_t str_len = strlen(str);
110	size_t sfx_len = strlen(sfx);
111
112	if (sfx_len > str_len)
113		return false;
114	return strcmp(str + str_len - sfx_len, sfx) == 0;
115}
116
117/* Symbol versioning is different between static and shared library.
118 * Properly versioned symbols are needed for shared library, but
119 * only the symbol of the new version is needed for static library.
120 * Starting with GNU C 10, use symver attribute instead of .symver assembler
121 * directive, which works better with GCC LTO builds.
122 */
123#if defined(SHARED) && defined(__GNUC__) && __GNUC__ >= 10
124
125#define DEFAULT_VERSION(internal_name, api_name, version) \
126	__attribute__((symver(#api_name "@@" #version)))
127#define COMPAT_VERSION(internal_name, api_name, version) \
128	__attribute__((symver(#api_name "@" #version)))
129
130#elif defined(SHARED)
131
132#define COMPAT_VERSION(internal_name, api_name, version) \
133	asm(".symver " #internal_name "," #api_name "@" #version);
134#define DEFAULT_VERSION(internal_name, api_name, version) \
135	asm(".symver " #internal_name "," #api_name "@@" #version);
136
137#else /* !SHARED */
138
139#define COMPAT_VERSION(internal_name, api_name, version)
140#define DEFAULT_VERSION(internal_name, api_name, version) \
141	extern typeof(internal_name) api_name \
142	__attribute__((alias(#internal_name)));
143
144#endif
145
146extern void libbpf_print(enum libbpf_print_level level,
147			 const char *format, ...)
148	__attribute__((format(printf, 2, 3)));
149
150#define __pr(level, fmt, ...)	\
151do {				\
152	libbpf_print(level, "libbpf: " fmt, ##__VA_ARGS__);	\
153} while (0)
154
155#define pr_warn(fmt, ...)	__pr(LIBBPF_WARN, fmt, ##__VA_ARGS__)
156#define pr_info(fmt, ...)	__pr(LIBBPF_INFO, fmt, ##__VA_ARGS__)
157#define pr_debug(fmt, ...)	__pr(LIBBPF_DEBUG, fmt, ##__VA_ARGS__)
158
159#ifndef __has_builtin
160#define __has_builtin(x) 0
161#endif
162
163struct bpf_link {
164	int (*detach)(struct bpf_link *link);
165	void (*dealloc)(struct bpf_link *link);
166	char *pin_path;		/* NULL, if not pinned */
167	int fd;			/* hook FD, -1 if not applicable */
168	bool disconnected;
169};
170
171/*
172 * Re-implement glibc's reallocarray() for libbpf internal-only use.
173 * reallocarray(), unfortunately, is not available in all versions of glibc,
174 * so requires extra feature detection and using reallocarray() stub from
175 * <tools/libc_compat.h> and COMPAT_NEED_REALLOCARRAY. All this complicates
176 * build of libbpf unnecessarily and is just a maintenance burden. Instead,
177 * it's trivial to implement libbpf-specific internal version and use it
178 * throughout libbpf.
179 */
180static inline void *libbpf_reallocarray(void *ptr, size_t nmemb, size_t size)
181{
182	size_t total;
183
184#if __has_builtin(__builtin_mul_overflow)
185	if (unlikely(__builtin_mul_overflow(nmemb, size, &total)))
186		return NULL;
187#else
188	if (size == 0 || nmemb > ULONG_MAX / size)
189		return NULL;
190	total = nmemb * size;
191#endif
192	return realloc(ptr, total);
193}
194
195/* Copy up to sz - 1 bytes from zero-terminated src string and ensure that dst
196 * is zero-terminated string no matter what (unless sz == 0, in which case
197 * it's a no-op). It's conceptually close to FreeBSD's strlcpy(), but differs
198 * in what is returned. Given this is internal helper, it's trivial to extend
199 * this, when necessary. Use this instead of strncpy inside libbpf source code.
200 */
201static inline void libbpf_strlcpy(char *dst, const char *src, size_t sz)
202{
203	size_t i;
204
205	if (sz == 0)
206		return;
207
208	sz--;
209	for (i = 0; i < sz && src[i]; i++)
210		dst[i] = src[i];
211	dst[i] = '\0';
212}
213
214__u32 get_kernel_version(void);
215
216struct btf;
217struct btf_type;
218
219struct btf_type *btf_type_by_id(const struct btf *btf, __u32 type_id);
220const char *btf_kind_str(const struct btf_type *t);
221const struct btf_type *skip_mods_and_typedefs(const struct btf *btf, __u32 id, __u32 *res_id);
222
223static inline enum btf_func_linkage btf_func_linkage(const struct btf_type *t)
224{
225	return (enum btf_func_linkage)(int)btf_vlen(t);
226}
227
228static inline __u32 btf_type_info(int kind, int vlen, int kflag)
229{
230	return (kflag << 31) | (kind << 24) | vlen;
231}
232
233enum map_def_parts {
234	MAP_DEF_MAP_TYPE	= 0x001,
235	MAP_DEF_KEY_TYPE	= 0x002,
236	MAP_DEF_KEY_SIZE	= 0x004,
237	MAP_DEF_VALUE_TYPE	= 0x008,
238	MAP_DEF_VALUE_SIZE	= 0x010,
239	MAP_DEF_MAX_ENTRIES	= 0x020,
240	MAP_DEF_MAP_FLAGS	= 0x040,
241	MAP_DEF_NUMA_NODE	= 0x080,
242	MAP_DEF_PINNING		= 0x100,
243	MAP_DEF_INNER_MAP	= 0x200,
244	MAP_DEF_MAP_EXTRA	= 0x400,
245
246	MAP_DEF_ALL		= 0x7ff, /* combination of all above */
247};
248
249struct btf_map_def {
250	enum map_def_parts parts;
251	__u32 map_type;
252	__u32 key_type_id;
253	__u32 key_size;
254	__u32 value_type_id;
255	__u32 value_size;
256	__u32 max_entries;
257	__u32 map_flags;
258	__u32 numa_node;
259	__u32 pinning;
260	__u64 map_extra;
261};
262
263int parse_btf_map_def(const char *map_name, struct btf *btf,
264		      const struct btf_type *def_t, bool strict,
265		      struct btf_map_def *map_def, struct btf_map_def *inner_def);
266
267void *libbpf_add_mem(void **data, size_t *cap_cnt, size_t elem_sz,
268		     size_t cur_cnt, size_t max_cnt, size_t add_cnt);
269int libbpf_ensure_mem(void **data, size_t *cap_cnt, size_t elem_sz, size_t need_cnt);
270
271static inline bool libbpf_is_mem_zeroed(const char *p, ssize_t len)
272{
273	while (len > 0) {
274		if (*p)
275			return false;
276		p++;
277		len--;
278	}
279	return true;
280}
281
282static inline bool libbpf_validate_opts(const char *opts,
283					size_t opts_sz, size_t user_sz,
284					const char *type_name)
285{
286	if (user_sz < sizeof(size_t)) {
287		pr_warn("%s size (%zu) is too small\n", type_name, user_sz);
288		return false;
289	}
290	if (!libbpf_is_mem_zeroed(opts + opts_sz, (ssize_t)user_sz - opts_sz)) {
291		pr_warn("%s has non-zero extra bytes\n", type_name);
292		return false;
293	}
294	return true;
295}
296
297#define OPTS_VALID(opts, type)						      \
298	(!(opts) || libbpf_validate_opts((const char *)opts,		      \
299					 offsetofend(struct type,	      \
300						     type##__last_field),     \
301					 (opts)->sz, #type))
302#define OPTS_HAS(opts, field) \
303	((opts) && opts->sz >= offsetofend(typeof(*(opts)), field))
304#define OPTS_GET(opts, field, fallback_value) \
305	(OPTS_HAS(opts, field) ? (opts)->field : fallback_value)
306#define OPTS_SET(opts, field, value)		\
307	do {					\
308		if (OPTS_HAS(opts, field))	\
309			(opts)->field = value;	\
310	} while (0)
311
312#define OPTS_ZEROED(opts, last_nonzero_field)				      \
313({									      \
314	ssize_t __off = offsetofend(typeof(*(opts)), last_nonzero_field);     \
315	!(opts) || libbpf_is_mem_zeroed((const void *)opts + __off,	      \
316					(opts)->sz - __off);		      \
317})
318
319enum kern_feature_id {
320	/* v4.14: kernel support for program & map names. */
321	FEAT_PROG_NAME,
322	/* v5.2: kernel support for global data sections. */
323	FEAT_GLOBAL_DATA,
324	/* BTF support */
325	FEAT_BTF,
326	/* BTF_KIND_FUNC and BTF_KIND_FUNC_PROTO support */
327	FEAT_BTF_FUNC,
328	/* BTF_KIND_VAR and BTF_KIND_DATASEC support */
329	FEAT_BTF_DATASEC,
330	/* BTF_FUNC_GLOBAL is supported */
331	FEAT_BTF_GLOBAL_FUNC,
332	/* BPF_F_MMAPABLE is supported for arrays */
333	FEAT_ARRAY_MMAP,
334	/* kernel support for expected_attach_type in BPF_PROG_LOAD */
335	FEAT_EXP_ATTACH_TYPE,
336	/* bpf_probe_read_{kernel,user}[_str] helpers */
337	FEAT_PROBE_READ_KERN,
338	/* BPF_PROG_BIND_MAP is supported */
339	FEAT_PROG_BIND_MAP,
340	/* Kernel support for module BTFs */
341	FEAT_MODULE_BTF,
342	/* BTF_KIND_FLOAT support */
343	FEAT_BTF_FLOAT,
344	/* BPF perf link support */
345	FEAT_PERF_LINK,
346	/* BTF_KIND_DECL_TAG support */
347	FEAT_BTF_DECL_TAG,
348	/* BTF_KIND_TYPE_TAG support */
349	FEAT_BTF_TYPE_TAG,
350	/* memcg-based accounting for BPF maps and progs */
351	FEAT_MEMCG_ACCOUNT,
352	/* BPF cookie (bpf_get_attach_cookie() BPF helper) support */
353	FEAT_BPF_COOKIE,
354	/* BTF_KIND_ENUM64 support and BTF_KIND_ENUM kflag support */
355	FEAT_BTF_ENUM64,
356	/* Kernel uses syscall wrapper (CONFIG_ARCH_HAS_SYSCALL_WRAPPER) */
357	FEAT_SYSCALL_WRAPPER,
358	/* BPF multi-uprobe link support */
359	FEAT_UPROBE_MULTI_LINK,
360	__FEAT_CNT,
361};
362
363int probe_memcg_account(void);
364bool kernel_supports(const struct bpf_object *obj, enum kern_feature_id feat_id);
365int bump_rlimit_memlock(void);
366
367int parse_cpu_mask_str(const char *s, bool **mask, int *mask_sz);
368int parse_cpu_mask_file(const char *fcpu, bool **mask, int *mask_sz);
369int libbpf__load_raw_btf(const char *raw_types, size_t types_len,
370			 const char *str_sec, size_t str_len);
371int btf_load_into_kernel(struct btf *btf, char *log_buf, size_t log_sz, __u32 log_level);
372
373struct btf *btf_get_from_fd(int btf_fd, struct btf *base_btf);
374void btf_get_kernel_prefix_kind(enum bpf_attach_type attach_type,
375				const char **prefix, int *kind);
376
377struct btf_ext_info {
378	/*
379	 * info points to the individual info section (e.g. func_info and
380	 * line_info) from the .BTF.ext. It does not include the __u32 rec_size.
381	 */
382	void *info;
383	__u32 rec_size;
384	__u32 len;
385	/* optional (maintained internally by libbpf) mapping between .BTF.ext
386	 * section and corresponding ELF section. This is used to join
387	 * information like CO-RE relocation records with corresponding BPF
388	 * programs defined in ELF sections
389	 */
390	__u32 *sec_idxs;
391	int sec_cnt;
392};
393
394#define for_each_btf_ext_sec(seg, sec)					\
395	for (sec = (seg)->info;						\
396	     (void *)sec < (seg)->info + (seg)->len;			\
397	     sec = (void *)sec + sizeof(struct btf_ext_info_sec) +	\
398		   (seg)->rec_size * sec->num_info)
399
400#define for_each_btf_ext_rec(seg, sec, i, rec)				\
401	for (i = 0, rec = (void *)&(sec)->data;				\
402	     i < (sec)->num_info;					\
403	     i++, rec = (void *)rec + (seg)->rec_size)
404
405/*
406 * The .BTF.ext ELF section layout defined as
407 *   struct btf_ext_header
408 *   func_info subsection
409 *
410 * The func_info subsection layout:
411 *   record size for struct bpf_func_info in the func_info subsection
412 *   struct btf_sec_func_info for section #1
413 *   a list of bpf_func_info records for section #1
414 *     where struct bpf_func_info mimics one in include/uapi/linux/bpf.h
415 *     but may not be identical
416 *   struct btf_sec_func_info for section #2
417 *   a list of bpf_func_info records for section #2
418 *   ......
419 *
420 * Note that the bpf_func_info record size in .BTF.ext may not
421 * be the same as the one defined in include/uapi/linux/bpf.h.
422 * The loader should ensure that record_size meets minimum
423 * requirement and pass the record as is to the kernel. The
424 * kernel will handle the func_info properly based on its contents.
425 */
426struct btf_ext_header {
427	__u16	magic;
428	__u8	version;
429	__u8	flags;
430	__u32	hdr_len;
431
432	/* All offsets are in bytes relative to the end of this header */
433	__u32	func_info_off;
434	__u32	func_info_len;
435	__u32	line_info_off;
436	__u32	line_info_len;
437
438	/* optional part of .BTF.ext header */
439	__u32	core_relo_off;
440	__u32	core_relo_len;
441};
442
443struct btf_ext {
444	union {
445		struct btf_ext_header *hdr;
446		void *data;
447	};
448	struct btf_ext_info func_info;
449	struct btf_ext_info line_info;
450	struct btf_ext_info core_relo_info;
451	__u32 data_size;
452};
453
454struct btf_ext_info_sec {
455	__u32	sec_name_off;
456	__u32	num_info;
457	/* Followed by num_info * record_size number of bytes */
458	__u8	data[];
459};
460
461/* The minimum bpf_func_info checked by the loader */
462struct bpf_func_info_min {
463	__u32   insn_off;
464	__u32   type_id;
465};
466
467/* The minimum bpf_line_info checked by the loader */
468struct bpf_line_info_min {
469	__u32	insn_off;
470	__u32	file_name_off;
471	__u32	line_off;
472	__u32	line_col;
473};
474
475
476typedef int (*type_id_visit_fn)(__u32 *type_id, void *ctx);
477typedef int (*str_off_visit_fn)(__u32 *str_off, void *ctx);
478int btf_type_visit_type_ids(struct btf_type *t, type_id_visit_fn visit, void *ctx);
479int btf_type_visit_str_offs(struct btf_type *t, str_off_visit_fn visit, void *ctx);
480int btf_ext_visit_type_ids(struct btf_ext *btf_ext, type_id_visit_fn visit, void *ctx);
481int btf_ext_visit_str_offs(struct btf_ext *btf_ext, str_off_visit_fn visit, void *ctx);
482__s32 btf__find_by_name_kind_own(const struct btf *btf, const char *type_name,
483				 __u32 kind);
484
485typedef int (*kallsyms_cb_t)(unsigned long long sym_addr, char sym_type,
486			     const char *sym_name, void *ctx);
487
488int libbpf_kallsyms_parse(kallsyms_cb_t cb, void *arg);
489
490/* handle direct returned errors */
491static inline int libbpf_err(int ret)
492{
493	if (ret < 0)
494		errno = -ret;
495	return ret;
496}
497
498/* handle errno-based (e.g., syscall or libc) errors according to libbpf's
499 * strict mode settings
500 */
501static inline int libbpf_err_errno(int ret)
502{
503	/* errno is already assumed to be set on error */
504	return ret < 0 ? -errno : ret;
505}
506
507/* handle error for pointer-returning APIs, err is assumed to be < 0 always */
508static inline void *libbpf_err_ptr(int err)
509{
510	/* set errno on error, this doesn't break anything */
511	errno = -err;
512	return NULL;
513}
514
515/* handle pointer-returning APIs' error handling */
516static inline void *libbpf_ptr(void *ret)
517{
518	/* set errno on error, this doesn't break anything */
519	if (IS_ERR(ret))
520		errno = -PTR_ERR(ret);
521
522	return IS_ERR(ret) ? NULL : ret;
523}
524
525static inline bool str_is_empty(const char *s)
526{
527	return !s || !s[0];
528}
529
530static inline bool is_ldimm64_insn(struct bpf_insn *insn)
531{
532	return insn->code == (BPF_LD | BPF_IMM | BPF_DW);
533}
534
535/* if fd is stdin, stdout, or stderr, dup to a fd greater than 2
536 * Takes ownership of the fd passed in, and closes it if calling
537 * fcntl(fd, F_DUPFD_CLOEXEC, 3).
538 */
539static inline int ensure_good_fd(int fd)
540{
541	int old_fd = fd, saved_errno;
542
543	if (fd < 0)
544		return fd;
545	if (fd < 3) {
546		fd = fcntl(fd, F_DUPFD_CLOEXEC, 3);
547		saved_errno = errno;
548		close(old_fd);
549		errno = saved_errno;
550		if (fd < 0) {
551			pr_warn("failed to dup FD %d to FD > 2: %d\n", old_fd, -saved_errno);
552			errno = saved_errno;
553		}
554	}
555	return fd;
556}
557
558/* Point *fixed_fd* to the same file that *tmp_fd* points to.
559 * Regardless of success, *tmp_fd* is closed.
560 * Whatever *fixed_fd* pointed to is closed silently.
561 */
562static inline int reuse_fd(int fixed_fd, int tmp_fd)
563{
564	int err;
565
566	err = dup2(tmp_fd, fixed_fd);
567	err = err < 0 ? -errno : 0;
568	close(tmp_fd); /* clean up temporary FD */
569	return err;
570}
571
572/* The following two functions are exposed to bpftool */
573int bpf_core_add_cands(struct bpf_core_cand *local_cand,
574		       size_t local_essent_len,
575		       const struct btf *targ_btf,
576		       const char *targ_btf_name,
577		       int targ_start_id,
578		       struct bpf_core_cand_list *cands);
579void bpf_core_free_cands(struct bpf_core_cand_list *cands);
580
581struct usdt_manager *usdt_manager_new(struct bpf_object *obj);
582void usdt_manager_free(struct usdt_manager *man);
583struct bpf_link * usdt_manager_attach_usdt(struct usdt_manager *man,
584					   const struct bpf_program *prog,
585					   pid_t pid, const char *path,
586					   const char *usdt_provider, const char *usdt_name,
587					   __u64 usdt_cookie);
588
589static inline bool is_pow_of_2(size_t x)
590{
591	return x && (x & (x - 1)) == 0;
592}
593
594#define PROG_LOAD_ATTEMPTS 5
595int sys_bpf_prog_load(union bpf_attr *attr, unsigned int size, int attempts);
596
597bool glob_match(const char *str, const char *pat);
598
599long elf_find_func_offset(Elf *elf, const char *binary_path, const char *name);
600long elf_find_func_offset_from_file(const char *binary_path, const char *name);
601
602struct elf_fd {
603	Elf *elf;
604	int fd;
605};
606
607int elf_open(const char *binary_path, struct elf_fd *elf_fd);
608void elf_close(struct elf_fd *elf_fd);
609
610int elf_resolve_syms_offsets(const char *binary_path, int cnt,
611			     const char **syms, unsigned long **poffsets,
612			     int st_type);
613int elf_resolve_pattern_offsets(const char *binary_path, const char *pattern,
614				 unsigned long **poffsets, size_t *pcnt);
615
616#endif /* __LIBBPF_LIBBPF_INTERNAL_H */