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 <sys/syscall.h>
19 #include <libelf.h>
20 #include "relo_core.h"
21
22 /* Android's libc doesn't support AT_EACCESS in faccessat() implementation
23 * ([0]), and just returns -EINVAL even if file exists and is accessible.
24 * See [1] for issues caused by this.
25 *
26 * So just redefine it to 0 on Android.
27 *
28 * [0] https://android.googlesource.com/platform/bionic/+/refs/heads/android13-release/libc/bionic/faccessat.cpp#50
29 * [1] https://github.com/libbpf/libbpf-bootstrap/issues/250#issuecomment-1911324250
30 */
31 #ifdef __ANDROID__
32 #undef AT_EACCESS
33 #define AT_EACCESS 0
34 #endif
35
36 /* make sure libbpf doesn't use kernel-only integer typedefs */
37 #pragma GCC poison u8 u16 u32 u64 s8 s16 s32 s64
38
39 /* prevent accidental re-addition of reallocarray() */
40 #pragma GCC poison reallocarray
41
42 #include "libbpf.h"
43 #include "btf.h"
44
45 #ifndef EM_BPF
46 #define EM_BPF 247
47 #endif
48
49 #ifndef R_BPF_64_64
50 #define R_BPF_64_64 1
51 #endif
52 #ifndef R_BPF_64_ABS64
53 #define R_BPF_64_ABS64 2
54 #endif
55 #ifndef R_BPF_64_ABS32
56 #define R_BPF_64_ABS32 3
57 #endif
58 #ifndef R_BPF_64_32
59 #define R_BPF_64_32 10
60 #endif
61
62 #ifndef SHT_LLVM_ADDRSIG
63 #define SHT_LLVM_ADDRSIG 0x6FFF4C03
64 #endif
65
66 /* if libelf is old and doesn't support mmap(), fall back to read() */
67 #ifndef ELF_C_READ_MMAP
68 #define ELF_C_READ_MMAP ELF_C_READ
69 #endif
70
71 /* Older libelf all end up in this expression, for both 32 and 64 bit */
72 #ifndef ELF64_ST_VISIBILITY
73 #define ELF64_ST_VISIBILITY(o) ((o) & 0x03)
74 #endif
75
76 #define BTF_INFO_ENC(kind, kind_flag, vlen) \
77 ((!!(kind_flag) << 31) | ((kind) << 24) | ((vlen) & BTF_MAX_VLEN))
78 #define BTF_TYPE_ENC(name, info, size_or_type) (name), (info), (size_or_type)
79 #define BTF_INT_ENC(encoding, bits_offset, nr_bits) \
80 ((encoding) << 24 | (bits_offset) << 16 | (nr_bits))
81 #define BTF_TYPE_INT_ENC(name, encoding, bits_offset, bits, sz) \
82 BTF_TYPE_ENC(name, BTF_INFO_ENC(BTF_KIND_INT, 0, 0), sz), \
83 BTF_INT_ENC(encoding, bits_offset, bits)
84 #define BTF_MEMBER_ENC(name, type, bits_offset) (name), (type), (bits_offset)
85 #define BTF_PARAM_ENC(name, type) (name), (type)
86 #define BTF_VAR_SECINFO_ENC(type, offset, size) (type), (offset), (size)
87 #define BTF_TYPE_FLOAT_ENC(name, sz) \
88 BTF_TYPE_ENC(name, BTF_INFO_ENC(BTF_KIND_FLOAT, 0, 0), sz)
89 #define BTF_TYPE_DECL_TAG_ENC(value, type, component_idx) \
90 BTF_TYPE_ENC(value, BTF_INFO_ENC(BTF_KIND_DECL_TAG, 0, 0), type), (component_idx)
91 #define BTF_TYPE_TYPE_TAG_ENC(value, type) \
92 BTF_TYPE_ENC(value, BTF_INFO_ENC(BTF_KIND_TYPE_TAG, 0, 0), type)
93
94 #ifndef likely
95 #define likely(x) __builtin_expect(!!(x), 1)
96 #endif
97 #ifndef unlikely
98 #define unlikely(x) __builtin_expect(!!(x), 0)
99 #endif
100 #ifndef min
101 # define min(x, y) ((x) < (y) ? (x) : (y))
102 #endif
103 #ifndef max
104 # define max(x, y) ((x) < (y) ? (y) : (x))
105 #endif
106 #ifndef offsetofend
107 # define offsetofend(TYPE, FIELD) \
108 (offsetof(TYPE, FIELD) + sizeof(((TYPE *)0)->FIELD))
109 #endif
110 #ifndef __alias
111 #define __alias(symbol) __attribute__((alias(#symbol)))
112 #endif
113
114 /* Check whether a string `str` has prefix `pfx`, regardless if `pfx` is
115 * a string literal known at compilation time or char * pointer known only at
116 * runtime.
117 */
118 #define str_has_pfx(str, pfx) \
119 (strncmp(str, pfx, __builtin_constant_p(pfx) ? sizeof(pfx) - 1 : strlen(pfx)) == 0)
120
121 /* suffix check */
str_has_sfx(const char * str,const char * sfx)122 static inline bool str_has_sfx(const char *str, const char *sfx)
123 {
124 size_t str_len = strlen(str);
125 size_t sfx_len = strlen(sfx);
126
127 if (sfx_len > str_len)
128 return false;
129 return strcmp(str + str_len - sfx_len, sfx) == 0;
130 }
131
132 /* Symbol versioning is different between static and shared library.
133 * Properly versioned symbols are needed for shared library, but
134 * only the symbol of the new version is needed for static library.
135 * Starting with GNU C 10, use symver attribute instead of .symver assembler
136 * directive, which works better with GCC LTO builds.
137 */
138 #if defined(SHARED) && defined(__GNUC__) && __GNUC__ >= 10
139
140 #define DEFAULT_VERSION(internal_name, api_name, version) \
141 __attribute__((symver(#api_name "@@" #version)))
142 #define COMPAT_VERSION(internal_name, api_name, version) \
143 __attribute__((symver(#api_name "@" #version)))
144
145 #elif defined(SHARED)
146
147 #define COMPAT_VERSION(internal_name, api_name, version) \
148 asm(".symver " #internal_name "," #api_name "@" #version);
149 #define DEFAULT_VERSION(internal_name, api_name, version) \
150 asm(".symver " #internal_name "," #api_name "@@" #version);
151
152 #else /* !SHARED */
153
154 #define COMPAT_VERSION(internal_name, api_name, version)
155 #define DEFAULT_VERSION(internal_name, api_name, version) \
156 extern typeof(internal_name) api_name \
157 __attribute__((alias(#internal_name)));
158
159 #endif
160
161 extern void libbpf_print(enum libbpf_print_level level,
162 const char *format, ...)
163 __attribute__((format(printf, 2, 3)));
164
165 #define __pr(level, fmt, ...) \
166 do { \
167 libbpf_print(level, "libbpf: " fmt, ##__VA_ARGS__); \
168 } while (0)
169
170 #define pr_warn(fmt, ...) __pr(LIBBPF_WARN, fmt, ##__VA_ARGS__)
171 #define pr_info(fmt, ...) __pr(LIBBPF_INFO, fmt, ##__VA_ARGS__)
172 #define pr_debug(fmt, ...) __pr(LIBBPF_DEBUG, fmt, ##__VA_ARGS__)
173
174 #ifndef __has_builtin
175 #define __has_builtin(x) 0
176 #endif
177
178 struct bpf_link {
179 int (*detach)(struct bpf_link *link);
180 void (*dealloc)(struct bpf_link *link);
181 char *pin_path; /* NULL, if not pinned */
182 int fd; /* hook FD, -1 if not applicable */
183 bool disconnected;
184 };
185
186 /*
187 * Re-implement glibc's reallocarray() for libbpf internal-only use.
188 * reallocarray(), unfortunately, is not available in all versions of glibc,
189 * so requires extra feature detection and using reallocarray() stub from
190 * <tools/libc_compat.h> and COMPAT_NEED_REALLOCARRAY. All this complicates
191 * build of libbpf unnecessarily and is just a maintenance burden. Instead,
192 * it's trivial to implement libbpf-specific internal version and use it
193 * throughout libbpf.
194 */
libbpf_reallocarray(void * ptr,size_t nmemb,size_t size)195 static inline void *libbpf_reallocarray(void *ptr, size_t nmemb, size_t size)
196 {
197 size_t total;
198
199 #if __has_builtin(__builtin_mul_overflow)
200 if (unlikely(__builtin_mul_overflow(nmemb, size, &total)))
201 return NULL;
202 #else
203 if (size == 0 || nmemb > ULONG_MAX / size)
204 return NULL;
205 total = nmemb * size;
206 #endif
207 return realloc(ptr, total);
208 }
209
210 /* Copy up to sz - 1 bytes from zero-terminated src string and ensure that dst
211 * is zero-terminated string no matter what (unless sz == 0, in which case
212 * it's a no-op). It's conceptually close to FreeBSD's strlcpy(), but differs
213 * in what is returned. Given this is internal helper, it's trivial to extend
214 * this, when necessary. Use this instead of strncpy inside libbpf source code.
215 */
libbpf_strlcpy(char * dst,const char * src,size_t sz)216 static inline void libbpf_strlcpy(char *dst, const char *src, size_t sz)
217 {
218 size_t i;
219
220 if (sz == 0)
221 return;
222
223 sz--;
224 for (i = 0; i < sz && src[i]; i++)
225 dst[i] = src[i];
226 dst[i] = '\0';
227 }
228
229 __u32 get_kernel_version(void);
230
231 struct btf;
232 struct btf_type;
233
234 struct btf_type *btf_type_by_id(const struct btf *btf, __u32 type_id);
235 const char *btf_kind_str(const struct btf_type *t);
236 const struct btf_type *skip_mods_and_typedefs(const struct btf *btf, __u32 id, __u32 *res_id);
237 const struct btf_header *btf_header(const struct btf *btf);
238 void btf_set_base_btf(struct btf *btf, const struct btf *base_btf);
239 int btf_relocate(struct btf *btf, const struct btf *base_btf, __u32 **id_map);
240
btf_func_linkage(const struct btf_type * t)241 static inline enum btf_func_linkage btf_func_linkage(const struct btf_type *t)
242 {
243 return (enum btf_func_linkage)(int)btf_vlen(t);
244 }
245
btf_type_info(int kind,int vlen,int kflag)246 static inline __u32 btf_type_info(int kind, int vlen, int kflag)
247 {
248 return (kflag << 31) | (kind << 24) | vlen;
249 }
250
251 enum map_def_parts {
252 MAP_DEF_MAP_TYPE = 0x001,
253 MAP_DEF_KEY_TYPE = 0x002,
254 MAP_DEF_KEY_SIZE = 0x004,
255 MAP_DEF_VALUE_TYPE = 0x008,
256 MAP_DEF_VALUE_SIZE = 0x010,
257 MAP_DEF_MAX_ENTRIES = 0x020,
258 MAP_DEF_MAP_FLAGS = 0x040,
259 MAP_DEF_NUMA_NODE = 0x080,
260 MAP_DEF_PINNING = 0x100,
261 MAP_DEF_INNER_MAP = 0x200,
262 MAP_DEF_MAP_EXTRA = 0x400,
263
264 MAP_DEF_ALL = 0x7ff, /* combination of all above */
265 };
266
267 struct btf_map_def {
268 enum map_def_parts parts;
269 __u32 map_type;
270 __u32 key_type_id;
271 __u32 key_size;
272 __u32 value_type_id;
273 __u32 value_size;
274 __u32 max_entries;
275 __u32 map_flags;
276 __u32 numa_node;
277 __u32 pinning;
278 __u64 map_extra;
279 };
280
281 int parse_btf_map_def(const char *map_name, struct btf *btf,
282 const struct btf_type *def_t, bool strict,
283 struct btf_map_def *map_def, struct btf_map_def *inner_def);
284
285 void *libbpf_add_mem(void **data, size_t *cap_cnt, size_t elem_sz,
286 size_t cur_cnt, size_t max_cnt, size_t add_cnt);
287 int libbpf_ensure_mem(void **data, size_t *cap_cnt, size_t elem_sz, size_t need_cnt);
288
libbpf_is_mem_zeroed(const char * p,ssize_t len)289 static inline bool libbpf_is_mem_zeroed(const char *p, ssize_t len)
290 {
291 while (len > 0) {
292 if (*p)
293 return false;
294 p++;
295 len--;
296 }
297 return true;
298 }
299
libbpf_validate_opts(const char * opts,size_t opts_sz,size_t user_sz,const char * type_name)300 static inline bool libbpf_validate_opts(const char *opts,
301 size_t opts_sz, size_t user_sz,
302 const char *type_name)
303 {
304 if (user_sz < sizeof(size_t)) {
305 pr_warn("%s size (%zu) is too small\n", type_name, user_sz);
306 return false;
307 }
308 if (!libbpf_is_mem_zeroed(opts + opts_sz, (ssize_t)user_sz - opts_sz)) {
309 pr_warn("%s has non-zero extra bytes\n", type_name);
310 return false;
311 }
312 return true;
313 }
314
315 #define OPTS_VALID(opts, type) \
316 (!(opts) || libbpf_validate_opts((const char *)opts, \
317 offsetofend(struct type, \
318 type##__last_field), \
319 (opts)->sz, #type))
320 #define OPTS_HAS(opts, field) \
321 ((opts) && opts->sz >= offsetofend(typeof(*(opts)), field))
322 #define OPTS_GET(opts, field, fallback_value) \
323 (OPTS_HAS(opts, field) ? (opts)->field : fallback_value)
324 #define OPTS_SET(opts, field, value) \
325 do { \
326 if (OPTS_HAS(opts, field)) \
327 (opts)->field = value; \
328 } while (0)
329
330 #define OPTS_ZEROED(opts, last_nonzero_field) \
331 ({ \
332 ssize_t __off = offsetofend(typeof(*(opts)), last_nonzero_field); \
333 !(opts) || libbpf_is_mem_zeroed((const void *)opts + __off, \
334 (opts)->sz - __off); \
335 })
336
337 enum kern_feature_id {
338 /* v4.14: kernel support for program & map names. */
339 FEAT_PROG_NAME,
340 /* v5.2: kernel support for global data sections. */
341 FEAT_GLOBAL_DATA,
342 /* BTF support */
343 FEAT_BTF,
344 /* BTF_KIND_FUNC and BTF_KIND_FUNC_PROTO support */
345 FEAT_BTF_FUNC,
346 /* BTF_KIND_VAR and BTF_KIND_DATASEC support */
347 FEAT_BTF_DATASEC,
348 /* BTF_FUNC_GLOBAL is supported */
349 FEAT_BTF_GLOBAL_FUNC,
350 /* BPF_F_MMAPABLE is supported for arrays */
351 FEAT_ARRAY_MMAP,
352 /* kernel support for expected_attach_type in BPF_PROG_LOAD */
353 FEAT_EXP_ATTACH_TYPE,
354 /* bpf_probe_read_{kernel,user}[_str] helpers */
355 FEAT_PROBE_READ_KERN,
356 /* BPF_PROG_BIND_MAP is supported */
357 FEAT_PROG_BIND_MAP,
358 /* Kernel support for module BTFs */
359 FEAT_MODULE_BTF,
360 /* BTF_KIND_FLOAT support */
361 FEAT_BTF_FLOAT,
362 /* BPF perf link support */
363 FEAT_PERF_LINK,
364 /* BTF_KIND_DECL_TAG support */
365 FEAT_BTF_DECL_TAG,
366 /* BTF_KIND_TYPE_TAG support */
367 FEAT_BTF_TYPE_TAG,
368 /* memcg-based accounting for BPF maps and progs */
369 FEAT_MEMCG_ACCOUNT,
370 /* BPF cookie (bpf_get_attach_cookie() BPF helper) support */
371 FEAT_BPF_COOKIE,
372 /* BTF_KIND_ENUM64 support and BTF_KIND_ENUM kflag support */
373 FEAT_BTF_ENUM64,
374 /* Kernel uses syscall wrapper (CONFIG_ARCH_HAS_SYSCALL_WRAPPER) */
375 FEAT_SYSCALL_WRAPPER,
376 /* BPF multi-uprobe link support */
377 FEAT_UPROBE_MULTI_LINK,
378 /* Kernel supports arg:ctx tag (__arg_ctx) for global subprogs natively */
379 FEAT_ARG_CTX_TAG,
380 /* Kernel supports '?' at the front of datasec names */
381 FEAT_BTF_QMARK_DATASEC,
382 __FEAT_CNT,
383 };
384
385 enum kern_feature_result {
386 FEAT_UNKNOWN = 0,
387 FEAT_SUPPORTED = 1,
388 FEAT_MISSING = 2,
389 };
390
391 struct kern_feature_cache {
392 enum kern_feature_result res[__FEAT_CNT];
393 int token_fd;
394 };
395
396 bool feat_supported(struct kern_feature_cache *cache, enum kern_feature_id feat_id);
397 bool kernel_supports(const struct bpf_object *obj, enum kern_feature_id feat_id);
398
399 int probe_kern_syscall_wrapper(int token_fd);
400 int probe_memcg_account(int token_fd);
401 int bump_rlimit_memlock(void);
402
403 int parse_cpu_mask_str(const char *s, bool **mask, int *mask_sz);
404 int parse_cpu_mask_file(const char *fcpu, bool **mask, int *mask_sz);
405 int libbpf__load_raw_btf(const char *raw_types, size_t types_len,
406 const char *str_sec, size_t str_len,
407 int token_fd);
408 int btf_load_into_kernel(struct btf *btf,
409 char *log_buf, size_t log_sz, __u32 log_level,
410 int token_fd);
411
412 struct btf *btf_get_from_fd(int btf_fd, struct btf *base_btf);
413 void btf_get_kernel_prefix_kind(enum bpf_attach_type attach_type,
414 const char **prefix, int *kind);
415
416 struct btf_ext_info {
417 /*
418 * info points to the individual info section (e.g. func_info and
419 * line_info) from the .BTF.ext. It does not include the __u32 rec_size.
420 */
421 void *info;
422 __u32 rec_size;
423 __u32 len;
424 /* optional (maintained internally by libbpf) mapping between .BTF.ext
425 * section and corresponding ELF section. This is used to join
426 * information like CO-RE relocation records with corresponding BPF
427 * programs defined in ELF sections
428 */
429 __u32 *sec_idxs;
430 int sec_cnt;
431 };
432
433 #define for_each_btf_ext_sec(seg, sec) \
434 for (sec = (seg)->info; \
435 (void *)sec < (seg)->info + (seg)->len; \
436 sec = (void *)sec + sizeof(struct btf_ext_info_sec) + \
437 (seg)->rec_size * sec->num_info)
438
439 #define for_each_btf_ext_rec(seg, sec, i, rec) \
440 for (i = 0, rec = (void *)&(sec)->data; \
441 i < (sec)->num_info; \
442 i++, rec = (void *)rec + (seg)->rec_size)
443
444 /*
445 * The .BTF.ext ELF section layout defined as
446 * struct btf_ext_header
447 * func_info subsection
448 *
449 * The func_info subsection layout:
450 * record size for struct bpf_func_info in the func_info subsection
451 * struct btf_sec_func_info for section #1
452 * a list of bpf_func_info records for section #1
453 * where struct bpf_func_info mimics one in include/uapi/linux/bpf.h
454 * but may not be identical
455 * struct btf_sec_func_info for section #2
456 * a list of bpf_func_info records for section #2
457 * ......
458 *
459 * Note that the bpf_func_info record size in .BTF.ext may not
460 * be the same as the one defined in include/uapi/linux/bpf.h.
461 * The loader should ensure that record_size meets minimum
462 * requirement and pass the record as is to the kernel. The
463 * kernel will handle the func_info properly based on its contents.
464 */
465 struct btf_ext_header {
466 __u16 magic;
467 __u8 version;
468 __u8 flags;
469 __u32 hdr_len;
470
471 /* All offsets are in bytes relative to the end of this header */
472 __u32 func_info_off;
473 __u32 func_info_len;
474 __u32 line_info_off;
475 __u32 line_info_len;
476
477 /* optional part of .BTF.ext header */
478 __u32 core_relo_off;
479 __u32 core_relo_len;
480 };
481
482 struct btf_ext {
483 union {
484 struct btf_ext_header *hdr;
485 void *data;
486 };
487 struct btf_ext_info func_info;
488 struct btf_ext_info line_info;
489 struct btf_ext_info core_relo_info;
490 __u32 data_size;
491 };
492
493 struct btf_ext_info_sec {
494 __u32 sec_name_off;
495 __u32 num_info;
496 /* Followed by num_info * record_size number of bytes */
497 __u8 data[];
498 };
499
500 /* The minimum bpf_func_info checked by the loader */
501 struct bpf_func_info_min {
502 __u32 insn_off;
503 __u32 type_id;
504 };
505
506 /* The minimum bpf_line_info checked by the loader */
507 struct bpf_line_info_min {
508 __u32 insn_off;
509 __u32 file_name_off;
510 __u32 line_off;
511 __u32 line_col;
512 };
513
514 enum btf_field_iter_kind {
515 BTF_FIELD_ITER_IDS,
516 BTF_FIELD_ITER_STRS,
517 };
518
519 struct btf_field_desc {
520 /* once-per-type offsets */
521 int t_off_cnt, t_offs[2];
522 /* member struct size, or zero, if no members */
523 int m_sz;
524 /* repeated per-member offsets */
525 int m_off_cnt, m_offs[1];
526 };
527
528 struct btf_field_iter {
529 struct btf_field_desc desc;
530 void *p;
531 int m_idx;
532 int off_idx;
533 int vlen;
534 };
535
536 int btf_field_iter_init(struct btf_field_iter *it, struct btf_type *t, enum btf_field_iter_kind iter_kind);
537 __u32 *btf_field_iter_next(struct btf_field_iter *it);
538
539 typedef int (*type_id_visit_fn)(__u32 *type_id, void *ctx);
540 typedef int (*str_off_visit_fn)(__u32 *str_off, void *ctx);
541 int btf_ext_visit_type_ids(struct btf_ext *btf_ext, type_id_visit_fn visit, void *ctx);
542 int btf_ext_visit_str_offs(struct btf_ext *btf_ext, str_off_visit_fn visit, void *ctx);
543 __s32 btf__find_by_name_kind_own(const struct btf *btf, const char *type_name,
544 __u32 kind);
545
546 /* handle direct returned errors */
libbpf_err(int ret)547 static inline int libbpf_err(int ret)
548 {
549 if (ret < 0)
550 errno = -ret;
551 return ret;
552 }
553
554 /* handle errno-based (e.g., syscall or libc) errors according to libbpf's
555 * strict mode settings
556 */
libbpf_err_errno(int ret)557 static inline int libbpf_err_errno(int ret)
558 {
559 /* errno is already assumed to be set on error */
560 return ret < 0 ? -errno : ret;
561 }
562
563 /* handle error for pointer-returning APIs, err is assumed to be < 0 always */
libbpf_err_ptr(int err)564 static inline void *libbpf_err_ptr(int err)
565 {
566 /* set errno on error, this doesn't break anything */
567 errno = -err;
568 return NULL;
569 }
570
571 /* handle pointer-returning APIs' error handling */
libbpf_ptr(void * ret)572 static inline void *libbpf_ptr(void *ret)
573 {
574 /* set errno on error, this doesn't break anything */
575 if (IS_ERR(ret))
576 errno = -PTR_ERR(ret);
577
578 return IS_ERR(ret) ? NULL : ret;
579 }
580
str_is_empty(const char * s)581 static inline bool str_is_empty(const char *s)
582 {
583 return !s || !s[0];
584 }
585
is_ldimm64_insn(struct bpf_insn * insn)586 static inline bool is_ldimm64_insn(struct bpf_insn *insn)
587 {
588 return insn->code == (BPF_LD | BPF_IMM | BPF_DW);
589 }
590
591 /* Unconditionally dup FD, ensuring it doesn't use [0, 2] range.
592 * Original FD is not closed or altered in any other way.
593 * Preserves original FD value, if it's invalid (negative).
594 */
dup_good_fd(int fd)595 static inline int dup_good_fd(int fd)
596 {
597 if (fd < 0)
598 return fd;
599 return fcntl(fd, F_DUPFD_CLOEXEC, 3);
600 }
601
602 /* if fd is stdin, stdout, or stderr, dup to a fd greater than 2
603 * Takes ownership of the fd passed in, and closes it if calling
604 * fcntl(fd, F_DUPFD_CLOEXEC, 3).
605 */
ensure_good_fd(int fd)606 static inline int ensure_good_fd(int fd)
607 {
608 int old_fd = fd, saved_errno;
609
610 if (fd < 0)
611 return fd;
612 if (fd < 3) {
613 fd = dup_good_fd(fd);
614 saved_errno = errno;
615 close(old_fd);
616 errno = saved_errno;
617 if (fd < 0) {
618 pr_warn("failed to dup FD %d to FD > 2: %d\n", old_fd, -saved_errno);
619 errno = saved_errno;
620 }
621 }
622 return fd;
623 }
624
sys_dup3(int oldfd,int newfd,int flags)625 static inline int sys_dup3(int oldfd, int newfd, int flags)
626 {
627 return syscall(__NR_dup3, oldfd, newfd, flags);
628 }
629
630 /* Point *fixed_fd* to the same file that *tmp_fd* points to.
631 * Regardless of success, *tmp_fd* is closed.
632 * Whatever *fixed_fd* pointed to is closed silently.
633 */
reuse_fd(int fixed_fd,int tmp_fd)634 static inline int reuse_fd(int fixed_fd, int tmp_fd)
635 {
636 int err;
637
638 err = sys_dup3(tmp_fd, fixed_fd, O_CLOEXEC);
639 err = err < 0 ? -errno : 0;
640 close(tmp_fd); /* clean up temporary FD */
641 return err;
642 }
643
644 /* The following two functions are exposed to bpftool */
645 int bpf_core_add_cands(struct bpf_core_cand *local_cand,
646 size_t local_essent_len,
647 const struct btf *targ_btf,
648 const char *targ_btf_name,
649 int targ_start_id,
650 struct bpf_core_cand_list *cands);
651 void bpf_core_free_cands(struct bpf_core_cand_list *cands);
652
653 struct usdt_manager *usdt_manager_new(struct bpf_object *obj);
654 void usdt_manager_free(struct usdt_manager *man);
655 struct bpf_link * usdt_manager_attach_usdt(struct usdt_manager *man,
656 const struct bpf_program *prog,
657 pid_t pid, const char *path,
658 const char *usdt_provider, const char *usdt_name,
659 __u64 usdt_cookie);
660
is_pow_of_2(size_t x)661 static inline bool is_pow_of_2(size_t x)
662 {
663 return x && (x & (x - 1)) == 0;
664 }
665
666 #define PROG_LOAD_ATTEMPTS 5
667 int sys_bpf_prog_load(union bpf_attr *attr, unsigned int size, int attempts);
668
669 bool glob_match(const char *str, const char *pat);
670
671 long elf_find_func_offset(Elf *elf, const char *binary_path, const char *name);
672 long elf_find_func_offset_from_file(const char *binary_path, const char *name);
673
674 struct elf_fd {
675 Elf *elf;
676 int fd;
677 };
678
679 int elf_open(const char *binary_path, struct elf_fd *elf_fd);
680 void elf_close(struct elf_fd *elf_fd);
681
682 int elf_resolve_syms_offsets(const char *binary_path, int cnt,
683 const char **syms, unsigned long **poffsets,
684 int st_type);
685 int elf_resolve_pattern_offsets(const char *binary_path, const char *pattern,
686 unsigned long **poffsets, size_t *pcnt);
687
688 int probe_fd(int fd);
689
690 #endif /* __LIBBPF_LIBBPF_INTERNAL_H */
691