1 /* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
4 * Internal libbpf helpers.
6 * Copyright (c) 2019 Facebook
9 #ifndef __LIBBPF_LIBBPF_INTERNAL_H
10 #define __LIBBPF_LIBBPF_INTERNAL_H
15 #include <linux/err.h>
18 #include "libbpf_legacy.h"
19 #include "relo_core.h"
21 /* make sure libbpf doesn't use kernel-only integer typedefs */
22 #pragma GCC poison u8 u16 u32 u64 s8 s16 s32 s64
24 /* prevent accidental re-addition of reallocarray() */
25 #pragma GCC poison reallocarray
37 #ifndef R_BPF_64_ABS64
38 #define R_BPF_64_ABS64 2
40 #ifndef R_BPF_64_ABS32
41 #define R_BPF_64_ABS32 3
44 #define R_BPF_64_32 10
47 #ifndef SHT_LLVM_ADDRSIG
48 #define SHT_LLVM_ADDRSIG 0x6FFF4C03
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
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)
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)
80 #define likely(x) __builtin_expect(!!(x), 1)
83 #define unlikely(x) __builtin_expect(!!(x), 0)
86 # define min(x, y) ((x) < (y) ? (x) : (y))
89 # define max(x, y) ((x) < (y) ? (y) : (x))
92 # define offsetofend(TYPE, FIELD) \
93 (offsetof(TYPE, FIELD) + sizeof(((TYPE *)0)->FIELD))
96 #define __alias(symbol) __attribute__((alias(#symbol)))
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
103 #define str_has_pfx(str, pfx) \
104 (strncmp(str, pfx, __builtin_constant_p(pfx) ? sizeof(pfx) - 1 : strlen(pfx)) == 0)
107 static inline bool str_has_sfx(const char *str, const char *sfx)
109 size_t str_len = strlen(str);
110 size_t sfx_len = strlen(sfx);
112 if (sfx_len <= str_len)
113 return strcmp(str + str_len - sfx_len, sfx);
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.
123 #if defined(SHARED) && defined(__GNUC__) && __GNUC__ >= 10
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)))
130 #elif defined(SHARED)
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);
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)));
146 extern void libbpf_print(enum libbpf_print_level level,
147 const char *format, ...)
148 __attribute__((format(printf, 2, 3)));
150 #define __pr(level, fmt, ...) \
152 libbpf_print(level, "libbpf: " fmt, ##__VA_ARGS__); \
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__)
159 #ifndef __has_builtin
160 #define __has_builtin(x) 0
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 */
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
180 static inline void *libbpf_reallocarray(void *ptr, size_t nmemb, size_t size)
184 #if __has_builtin(__builtin_mul_overflow)
185 if (unlikely(__builtin_mul_overflow(nmemb, size, &total)))
188 if (size == 0 || nmemb > ULONG_MAX / size)
190 total = nmemb * size;
192 return realloc(ptr, total);
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.
201 static inline void libbpf_strlcpy(char *dst, const char *src, size_t sz)
209 for (i = 0; i < sz && src[i]; i++)
214 __u32 get_kernel_version(void);
219 struct btf_type *btf_type_by_id(const struct btf *btf, __u32 type_id);
220 const char *btf_kind_str(const struct btf_type *t);
221 const struct btf_type *skip_mods_and_typedefs(const struct btf *btf, __u32 id, __u32 *res_id);
223 static inline enum btf_func_linkage btf_func_linkage(const struct btf_type *t)
225 return (enum btf_func_linkage)(int)btf_vlen(t);
228 static inline __u32 btf_type_info(int kind, int vlen, int kflag)
230 return (kflag << 31) | (kind << 24) | vlen;
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,
246 MAP_DEF_ALL = 0x7ff, /* combination of all above */
250 enum map_def_parts parts;
263 int 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);
267 void *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);
269 int libbpf_ensure_mem(void **data, size_t *cap_cnt, size_t elem_sz, size_t need_cnt);
271 static inline bool libbpf_is_mem_zeroed(const char *p, ssize_t len)
282 static inline bool libbpf_validate_opts(const char *opts,
283 size_t opts_sz, size_t user_sz,
284 const char *type_name)
286 if (user_sz < sizeof(size_t)) {
287 pr_warn("%s size (%zu) is too small\n", type_name, user_sz);
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);
297 #define OPTS_VALID(opts, type) \
298 (!(opts) || libbpf_validate_opts((const char *)opts, \
299 offsetofend(struct type, \
300 type##__last_field), \
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) \
308 if (OPTS_HAS(opts, field)) \
309 (opts)->field = value; \
312 #define OPTS_ZEROED(opts, last_nonzero_field) \
314 ssize_t __off = offsetofend(typeof(*(opts)), last_nonzero_field); \
315 !(opts) || libbpf_is_mem_zeroed((const void *)opts + __off, \
316 (opts)->sz - __off); \
319 enum kern_feature_id {
320 /* v4.14: kernel support for program & map names. */
322 /* v5.2: kernel support for global data sections. */
326 /* BTF_KIND_FUNC and BTF_KIND_FUNC_PROTO support */
328 /* BTF_KIND_VAR and BTF_KIND_DATASEC support */
330 /* BTF_FUNC_GLOBAL is supported */
331 FEAT_BTF_GLOBAL_FUNC,
332 /* BPF_F_MMAPABLE is supported for arrays */
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 */
340 /* Kernel support for module BTFs */
342 /* BTF_KIND_FLOAT support */
344 /* BPF perf link support */
346 /* BTF_KIND_DECL_TAG support */
348 /* BTF_KIND_TYPE_TAG support */
350 /* memcg-based accounting for BPF maps and progs */
352 /* BPF cookie (bpf_get_attach_cookie() BPF helper) support */
357 int probe_memcg_account(void);
358 bool kernel_supports(const struct bpf_object *obj, enum kern_feature_id feat_id);
359 int bump_rlimit_memlock(void);
361 int parse_cpu_mask_str(const char *s, bool **mask, int *mask_sz);
362 int parse_cpu_mask_file(const char *fcpu, bool **mask, int *mask_sz);
363 int libbpf__load_raw_btf(const char *raw_types, size_t types_len,
364 const char *str_sec, size_t str_len);
365 int btf_load_into_kernel(struct btf *btf, char *log_buf, size_t log_sz, __u32 log_level);
367 struct btf *btf_get_from_fd(int btf_fd, struct btf *base_btf);
368 void btf_get_kernel_prefix_kind(enum bpf_attach_type attach_type,
369 const char **prefix, int *kind);
371 struct btf_ext_info {
373 * info points to the individual info section (e.g. func_info and
374 * line_info) from the .BTF.ext. It does not include the __u32 rec_size.
379 /* optional (maintained internally by libbpf) mapping between .BTF.ext
380 * section and corresponding ELF section. This is used to join
381 * information like CO-RE relocation records with corresponding BPF
382 * programs defined in ELF sections
388 #define for_each_btf_ext_sec(seg, sec) \
389 for (sec = (seg)->info; \
390 (void *)sec < (seg)->info + (seg)->len; \
391 sec = (void *)sec + sizeof(struct btf_ext_info_sec) + \
392 (seg)->rec_size * sec->num_info)
394 #define for_each_btf_ext_rec(seg, sec, i, rec) \
395 for (i = 0, rec = (void *)&(sec)->data; \
396 i < (sec)->num_info; \
397 i++, rec = (void *)rec + (seg)->rec_size)
400 * The .BTF.ext ELF section layout defined as
401 * struct btf_ext_header
402 * func_info subsection
404 * The func_info subsection layout:
405 * record size for struct bpf_func_info in the func_info subsection
406 * struct btf_sec_func_info for section #1
407 * a list of bpf_func_info records for section #1
408 * where struct bpf_func_info mimics one in include/uapi/linux/bpf.h
409 * but may not be identical
410 * struct btf_sec_func_info for section #2
411 * a list of bpf_func_info records for section #2
414 * Note that the bpf_func_info record size in .BTF.ext may not
415 * be the same as the one defined in include/uapi/linux/bpf.h.
416 * The loader should ensure that record_size meets minimum
417 * requirement and pass the record as is to the kernel. The
418 * kernel will handle the func_info properly based on its contents.
420 struct btf_ext_header {
426 /* All offsets are in bytes relative to the end of this header */
432 /* optional part of .BTF.ext header */
439 struct btf_ext_header *hdr;
442 struct btf_ext_info func_info;
443 struct btf_ext_info line_info;
444 struct btf_ext_info core_relo_info;
448 struct btf_ext_info_sec {
451 /* Followed by num_info * record_size number of bytes */
455 /* The minimum bpf_func_info checked by the loader */
456 struct bpf_func_info_min {
461 /* The minimum bpf_line_info checked by the loader */
462 struct bpf_line_info_min {
470 typedef int (*type_id_visit_fn)(__u32 *type_id, void *ctx);
471 typedef int (*str_off_visit_fn)(__u32 *str_off, void *ctx);
472 int btf_type_visit_type_ids(struct btf_type *t, type_id_visit_fn visit, void *ctx);
473 int btf_type_visit_str_offs(struct btf_type *t, str_off_visit_fn visit, void *ctx);
474 int btf_ext_visit_type_ids(struct btf_ext *btf_ext, type_id_visit_fn visit, void *ctx);
475 int btf_ext_visit_str_offs(struct btf_ext *btf_ext, str_off_visit_fn visit, void *ctx);
476 __s32 btf__find_by_name_kind_own(const struct btf *btf, const char *type_name,
479 extern enum libbpf_strict_mode libbpf_mode;
481 typedef int (*kallsyms_cb_t)(unsigned long long sym_addr, char sym_type,
482 const char *sym_name, void *ctx);
484 int libbpf_kallsyms_parse(kallsyms_cb_t cb, void *arg);
486 /* handle direct returned errors */
487 static inline int libbpf_err(int ret)
494 /* handle errno-based (e.g., syscall or libc) errors according to libbpf's
495 * strict mode settings
497 static inline int libbpf_err_errno(int ret)
499 if (libbpf_mode & LIBBPF_STRICT_DIRECT_ERRS)
500 /* errno is already assumed to be set on error */
501 return ret < 0 ? -errno : ret;
503 /* legacy: on error return -1 directly and don't touch errno */
507 /* handle error for pointer-returning APIs, err is assumed to be < 0 always */
508 static inline void *libbpf_err_ptr(int err)
510 /* set errno on error, this doesn't break anything */
513 if (libbpf_mode & LIBBPF_STRICT_CLEAN_PTRS)
516 /* legacy: encode err as ptr */
520 /* handle pointer-returning APIs' error handling */
521 static inline void *libbpf_ptr(void *ret)
523 /* set errno on error, this doesn't break anything */
525 errno = -PTR_ERR(ret);
527 if (libbpf_mode & LIBBPF_STRICT_CLEAN_PTRS)
528 return IS_ERR(ret) ? NULL : ret;
530 /* legacy: pass-through original pointer */
534 static inline bool str_is_empty(const char *s)
539 static inline bool is_ldimm64_insn(struct bpf_insn *insn)
541 return insn->code == (BPF_LD | BPF_IMM | BPF_DW);
544 /* if fd is stdin, stdout, or stderr, dup to a fd greater than 2
545 * Takes ownership of the fd passed in, and closes it if calling
546 * fcntl(fd, F_DUPFD_CLOEXEC, 3).
548 static inline int ensure_good_fd(int fd)
550 int old_fd = fd, saved_errno;
555 fd = fcntl(fd, F_DUPFD_CLOEXEC, 3);
559 pr_warn("failed to dup FD %d to FD > 2: %d\n", old_fd, -saved_errno);
566 /* The following two functions are exposed to bpftool */
567 int bpf_core_add_cands(struct bpf_core_cand *local_cand,
568 size_t local_essent_len,
569 const struct btf *targ_btf,
570 const char *targ_btf_name,
572 struct bpf_core_cand_list *cands);
573 void bpf_core_free_cands(struct bpf_core_cand_list *cands);
575 struct usdt_manager *usdt_manager_new(struct bpf_object *obj);
576 void usdt_manager_free(struct usdt_manager *man);
577 struct bpf_link * usdt_manager_attach_usdt(struct usdt_manager *man,
578 const struct bpf_program *prog,
579 pid_t pid, const char *path,
580 const char *usdt_provider, const char *usdt_name,
583 #endif /* __LIBBPF_LIBBPF_INTERNAL_H */