Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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linux
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 <byteswap.h>
14#include <limits.h>
15#include <errno.h>
16#include <linux/err.h>
17#include <fcntl.h>
18#include <unistd.h>
19#include <sys/syscall.h>
20#include <libelf.h>
21#include "relo_core.h"
22
23/* Android's libc doesn't support AT_EACCESS in faccessat() implementation
24 * ([0]), and just returns -EINVAL even if file exists and is accessible.
25 * See [1] for issues caused by this.
26 *
27 * So just redefine it to 0 on Android.
28 *
29 * [0] https://android.googlesource.com/platform/bionic/+/refs/heads/android13-release/libc/bionic/faccessat.cpp#50
30 * [1] https://github.com/libbpf/libbpf-bootstrap/issues/250#issuecomment-1911324250
31 */
32#ifdef __ANDROID__
33#undef AT_EACCESS
34#define AT_EACCESS 0
35#endif
36
37/* make sure libbpf doesn't use kernel-only integer typedefs */
38#pragma GCC poison u8 u16 u32 u64 s8 s16 s32 s64
39
40/* prevent accidental re-addition of reallocarray() */
41#pragma GCC poison reallocarray
42
43#include "libbpf.h"
44#include "btf.h"
45
46#ifndef EM_BPF
47#define EM_BPF 247
48#endif
49
50#ifndef R_BPF_64_64
51#define R_BPF_64_64 1
52#endif
53#ifndef R_BPF_64_ABS64
54#define R_BPF_64_ABS64 2
55#endif
56#ifndef R_BPF_64_ABS32
57#define R_BPF_64_ABS32 3
58#endif
59#ifndef R_BPF_64_32
60#define R_BPF_64_32 10
61#endif
62
63#ifndef SHT_LLVM_ADDRSIG
64#define SHT_LLVM_ADDRSIG 0x6FFF4C03
65#endif
66
67/* if libelf is old and doesn't support mmap(), fall back to read() */
68#ifndef ELF_C_READ_MMAP
69#define ELF_C_READ_MMAP ELF_C_READ
70#endif
71
72/* Older libelf all end up in this expression, for both 32 and 64 bit */
73#ifndef ELF64_ST_VISIBILITY
74#define ELF64_ST_VISIBILITY(o) ((o) & 0x03)
75#endif
76
77#define JUMPTABLES_SEC ".jumptables"
78
79#define BTF_INFO_ENC(kind, kind_flag, vlen) \
80 ((!!(kind_flag) << 31) | ((kind) << 24) | ((vlen) & BTF_MAX_VLEN))
81#define BTF_TYPE_ENC(name, info, size_or_type) (name), (info), (size_or_type)
82#define BTF_INT_ENC(encoding, bits_offset, nr_bits) \
83 ((encoding) << 24 | (bits_offset) << 16 | (nr_bits))
84#define BTF_TYPE_INT_ENC(name, encoding, bits_offset, bits, sz) \
85 BTF_TYPE_ENC(name, BTF_INFO_ENC(BTF_KIND_INT, 0, 0), sz), \
86 BTF_INT_ENC(encoding, bits_offset, bits)
87#define BTF_MEMBER_ENC(name, type, bits_offset) (name), (type), (bits_offset)
88#define BTF_PARAM_ENC(name, type) (name), (type)
89#define BTF_VAR_SECINFO_ENC(type, offset, size) (type), (offset), (size)
90#define BTF_TYPE_FLOAT_ENC(name, sz) \
91 BTF_TYPE_ENC(name, BTF_INFO_ENC(BTF_KIND_FLOAT, 0, 0), sz)
92#define BTF_TYPE_DECL_TAG_ENC(value, type, component_idx) \
93 BTF_TYPE_ENC(value, BTF_INFO_ENC(BTF_KIND_DECL_TAG, 0, 0), type), (component_idx)
94#define BTF_TYPE_TYPE_TAG_ENC(value, type) \
95 BTF_TYPE_ENC(value, BTF_INFO_ENC(BTF_KIND_TYPE_TAG, 0, 0), type)
96
97#ifndef likely
98#define likely(x) __builtin_expect(!!(x), 1)
99#endif
100#ifndef unlikely
101#define unlikely(x) __builtin_expect(!!(x), 0)
102#endif
103#ifndef min
104# define min(x, y) ((x) < (y) ? (x) : (y))
105#endif
106#ifndef max
107# define max(x, y) ((x) < (y) ? (y) : (x))
108#endif
109#ifndef offsetofend
110# define offsetofend(TYPE, FIELD) \
111 (offsetof(TYPE, FIELD) + sizeof(((TYPE *)0)->FIELD))
112#endif
113#ifndef __alias
114#define __alias(symbol) __attribute__((alias(#symbol)))
115#endif
116
117/* Check whether a string `str` has prefix `pfx`, regardless if `pfx` is
118 * a string literal known at compilation time or char * pointer known only at
119 * runtime.
120 */
121#define str_has_pfx(str, pfx) \
122 (strncmp(str, pfx, __builtin_constant_p(pfx) ? sizeof(pfx) - 1 : strlen(pfx)) == 0)
123
124/* suffix check */
125static inline bool str_has_sfx(const char *str, const char *sfx)
126{
127 size_t str_len = strlen(str);
128 size_t sfx_len = strlen(sfx);
129
130 if (sfx_len > str_len)
131 return false;
132 return strcmp(str + str_len - sfx_len, sfx) == 0;
133}
134
135/* Symbol versioning is different between static and shared library.
136 * Properly versioned symbols are needed for shared library, but
137 * only the symbol of the new version is needed for static library.
138 * Starting with GNU C 10, use symver attribute instead of .symver assembler
139 * directive, which works better with GCC LTO builds.
140 */
141#if defined(SHARED) && defined(__GNUC__) && __GNUC__ >= 10
142
143#define DEFAULT_VERSION(internal_name, api_name, version) \
144 __attribute__((symver(#api_name "@@" #version)))
145#define COMPAT_VERSION(internal_name, api_name, version) \
146 __attribute__((symver(#api_name "@" #version)))
147
148#elif defined(SHARED)
149
150#define COMPAT_VERSION(internal_name, api_name, version) \
151 asm(".symver " #internal_name "," #api_name "@" #version);
152#define DEFAULT_VERSION(internal_name, api_name, version) \
153 asm(".symver " #internal_name "," #api_name "@@" #version);
154
155#else /* !SHARED */
156
157#define COMPAT_VERSION(internal_name, api_name, version)
158#define DEFAULT_VERSION(internal_name, api_name, version) \
159 extern typeof(internal_name) api_name \
160 __attribute__((alias(#internal_name)));
161
162#endif
163
164extern void libbpf_print(enum libbpf_print_level level,
165 const char *format, ...)
166 __attribute__((format(printf, 2, 3)));
167
168#define __pr(level, fmt, ...) \
169do { \
170 libbpf_print(level, "libbpf: " fmt, ##__VA_ARGS__); \
171} while (0)
172
173#define pr_warn(fmt, ...) __pr(LIBBPF_WARN, fmt, ##__VA_ARGS__)
174#define pr_info(fmt, ...) __pr(LIBBPF_INFO, fmt, ##__VA_ARGS__)
175#define pr_debug(fmt, ...) __pr(LIBBPF_DEBUG, fmt, ##__VA_ARGS__)
176
177/**
178 * @brief **libbpf_errstr()** returns string corresponding to numeric errno
179 * @param err negative numeric errno
180 * @return pointer to string representation of the errno, that is invalidated
181 * upon the next call.
182 */
183const char *libbpf_errstr(int err);
184
185#define errstr(err) libbpf_errstr(err)
186
187#ifndef __has_builtin
188#define __has_builtin(x) 0
189#endif
190
191struct bpf_link {
192 int (*detach)(struct bpf_link *link);
193 void (*dealloc)(struct bpf_link *link);
194 char *pin_path; /* NULL, if not pinned */
195 int fd; /* hook FD, -1 if not applicable */
196 bool disconnected;
197};
198
199/*
200 * Re-implement glibc's reallocarray() for libbpf internal-only use.
201 * reallocarray(), unfortunately, is not available in all versions of glibc,
202 * so requires extra feature detection and using reallocarray() stub from
203 * <tools/libc_compat.h> and COMPAT_NEED_REALLOCARRAY. All this complicates
204 * build of libbpf unnecessarily and is just a maintenance burden. Instead,
205 * it's trivial to implement libbpf-specific internal version and use it
206 * throughout libbpf.
207 */
208static inline void *libbpf_reallocarray(void *ptr, size_t nmemb, size_t size)
209{
210 size_t total;
211
212#if __has_builtin(__builtin_mul_overflow)
213 if (unlikely(__builtin_mul_overflow(nmemb, size, &total)))
214 return NULL;
215#else
216 if (size == 0 || nmemb > ULONG_MAX / size)
217 return NULL;
218 total = nmemb * size;
219#endif
220 return realloc(ptr, total);
221}
222
223/* Copy up to sz - 1 bytes from zero-terminated src string and ensure that dst
224 * is zero-terminated string no matter what (unless sz == 0, in which case
225 * it's a no-op). It's conceptually close to FreeBSD's strlcpy(), but differs
226 * in what is returned. Given this is internal helper, it's trivial to extend
227 * this, when necessary. Use this instead of strncpy inside libbpf source code.
228 */
229static inline void libbpf_strlcpy(char *dst, const char *src, size_t sz)
230{
231 size_t i;
232
233 if (sz == 0)
234 return;
235
236 sz--;
237 for (i = 0; i < sz && src[i]; i++)
238 dst[i] = src[i];
239 dst[i] = '\0';
240}
241
242__u32 get_kernel_version(void);
243
244struct btf;
245struct btf_type;
246
247struct btf_type *btf_type_by_id(const struct btf *btf, __u32 type_id);
248const char *btf_kind_str(const struct btf_type *t);
249const struct btf_type *skip_mods_and_typedefs(const struct btf *btf, __u32 id, __u32 *res_id);
250const struct btf_header *btf_header(const struct btf *btf);
251void btf_set_base_btf(struct btf *btf, const struct btf *base_btf);
252int btf_relocate(struct btf *btf, const struct btf *base_btf, __u32 **id_map);
253
254static inline enum btf_func_linkage btf_func_linkage(const struct btf_type *t)
255{
256 return (enum btf_func_linkage)(int)btf_vlen(t);
257}
258
259static inline __u32 btf_type_info(int kind, int vlen, int kflag)
260{
261 return (kflag << 31) | (kind << 24) | vlen;
262}
263
264enum map_def_parts {
265 MAP_DEF_MAP_TYPE = 0x001,
266 MAP_DEF_KEY_TYPE = 0x002,
267 MAP_DEF_KEY_SIZE = 0x004,
268 MAP_DEF_VALUE_TYPE = 0x008,
269 MAP_DEF_VALUE_SIZE = 0x010,
270 MAP_DEF_MAX_ENTRIES = 0x020,
271 MAP_DEF_MAP_FLAGS = 0x040,
272 MAP_DEF_NUMA_NODE = 0x080,
273 MAP_DEF_PINNING = 0x100,
274 MAP_DEF_INNER_MAP = 0x200,
275 MAP_DEF_MAP_EXTRA = 0x400,
276
277 MAP_DEF_ALL = 0x7ff, /* combination of all above */
278};
279
280struct btf_map_def {
281 enum map_def_parts parts;
282 __u32 map_type;
283 __u32 key_type_id;
284 __u32 key_size;
285 __u32 value_type_id;
286 __u32 value_size;
287 __u32 max_entries;
288 __u32 map_flags;
289 __u32 numa_node;
290 __u32 pinning;
291 __u64 map_extra;
292};
293
294int parse_btf_map_def(const char *map_name, struct btf *btf,
295 const struct btf_type *def_t, bool strict,
296 struct btf_map_def *map_def, struct btf_map_def *inner_def);
297
298void *libbpf_add_mem(void **data, size_t *cap_cnt, size_t elem_sz,
299 size_t cur_cnt, size_t max_cnt, size_t add_cnt);
300int libbpf_ensure_mem(void **data, size_t *cap_cnt, size_t elem_sz, size_t need_cnt);
301
302static inline bool libbpf_is_mem_zeroed(const char *p, ssize_t len)
303{
304 while (len > 0) {
305 if (*p)
306 return false;
307 p++;
308 len--;
309 }
310 return true;
311}
312
313static inline bool libbpf_validate_opts(const char *opts,
314 size_t opts_sz, size_t user_sz,
315 const char *type_name)
316{
317 if (user_sz < sizeof(size_t)) {
318 pr_warn("%s size (%zu) is too small\n", type_name, user_sz);
319 return false;
320 }
321 if (!libbpf_is_mem_zeroed(opts + opts_sz, (ssize_t)user_sz - opts_sz)) {
322 pr_warn("%s has non-zero extra bytes\n", type_name);
323 return false;
324 }
325 return true;
326}
327
328#define OPTS_VALID(opts, type) \
329 (!(opts) || libbpf_validate_opts((const char *)opts, \
330 offsetofend(struct type, \
331 type##__last_field), \
332 (opts)->sz, #type))
333#define OPTS_HAS(opts, field) \
334 ((opts) && opts->sz >= offsetofend(typeof(*(opts)), field))
335#define OPTS_GET(opts, field, fallback_value) \
336 (OPTS_HAS(opts, field) ? (opts)->field : fallback_value)
337#define OPTS_SET(opts, field, value) \
338 do { \
339 if (OPTS_HAS(opts, field)) \
340 (opts)->field = value; \
341 } while (0)
342
343#define OPTS_ZEROED(opts, last_nonzero_field) \
344({ \
345 ssize_t __off = offsetofend(typeof(*(opts)), last_nonzero_field); \
346 !(opts) || libbpf_is_mem_zeroed((const void *)opts + __off, \
347 (opts)->sz - __off); \
348})
349
350enum kern_feature_id {
351 /* v4.14: kernel support for program & map names. */
352 FEAT_PROG_NAME,
353 /* v5.2: kernel support for global data sections. */
354 FEAT_GLOBAL_DATA,
355 /* BTF support */
356 FEAT_BTF,
357 /* BTF_KIND_FUNC and BTF_KIND_FUNC_PROTO support */
358 FEAT_BTF_FUNC,
359 /* BTF_KIND_VAR and BTF_KIND_DATASEC support */
360 FEAT_BTF_DATASEC,
361 /* BTF_FUNC_GLOBAL is supported */
362 FEAT_BTF_GLOBAL_FUNC,
363 /* BPF_F_MMAPABLE is supported for arrays */
364 FEAT_ARRAY_MMAP,
365 /* kernel support for expected_attach_type in BPF_PROG_LOAD */
366 FEAT_EXP_ATTACH_TYPE,
367 /* bpf_probe_read_{kernel,user}[_str] helpers */
368 FEAT_PROBE_READ_KERN,
369 /* BPF_PROG_BIND_MAP is supported */
370 FEAT_PROG_BIND_MAP,
371 /* Kernel support for module BTFs */
372 FEAT_MODULE_BTF,
373 /* BTF_KIND_FLOAT support */
374 FEAT_BTF_FLOAT,
375 /* BPF perf link support */
376 FEAT_PERF_LINK,
377 /* BTF_KIND_DECL_TAG support */
378 FEAT_BTF_DECL_TAG,
379 /* BTF_KIND_TYPE_TAG support */
380 FEAT_BTF_TYPE_TAG,
381 /* memcg-based accounting for BPF maps and progs */
382 FEAT_MEMCG_ACCOUNT,
383 /* BPF cookie (bpf_get_attach_cookie() BPF helper) support */
384 FEAT_BPF_COOKIE,
385 /* BTF_KIND_ENUM64 support and BTF_KIND_ENUM kflag support */
386 FEAT_BTF_ENUM64,
387 /* Kernel uses syscall wrapper (CONFIG_ARCH_HAS_SYSCALL_WRAPPER) */
388 FEAT_SYSCALL_WRAPPER,
389 /* BPF multi-uprobe link support */
390 FEAT_UPROBE_MULTI_LINK,
391 /* Kernel supports arg:ctx tag (__arg_ctx) for global subprogs natively */
392 FEAT_ARG_CTX_TAG,
393 /* Kernel supports '?' at the front of datasec names */
394 FEAT_BTF_QMARK_DATASEC,
395 /* Kernel supports LDIMM64 imm offsets past 512 MiB. */
396 FEAT_LDIMM64_FULL_RANGE_OFF,
397 /* Kernel supports uprobe syscall */
398 FEAT_UPROBE_SYSCALL,
399 /* Kernel supports BTF layout information */
400 FEAT_BTF_LAYOUT,
401 __FEAT_CNT,
402};
403
404enum kern_feature_result {
405 FEAT_UNKNOWN = 0,
406 FEAT_SUPPORTED = 1,
407 FEAT_MISSING = 2,
408};
409
410struct kern_feature_cache {
411 enum kern_feature_result res[__FEAT_CNT];
412 int token_fd;
413};
414
415bool feat_supported(struct kern_feature_cache *cache, enum kern_feature_id feat_id);
416bool kernel_supports(const struct bpf_object *obj, enum kern_feature_id feat_id);
417void bpf_object_set_feat_cache(struct bpf_object *obj, struct kern_feature_cache *cache);
418
419int probe_kern_syscall_wrapper(int token_fd);
420int probe_memcg_account(int token_fd);
421int bump_rlimit_memlock(void);
422
423int parse_cpu_mask_str(const char *s, bool **mask, int *mask_sz);
424int parse_cpu_mask_file(const char *fcpu, bool **mask, int *mask_sz);
425int libbpf__load_raw_btf(const char *raw_types, size_t types_len,
426 const char *str_sec, size_t str_len,
427 int token_fd);
428int libbpf__load_raw_btf_hdr(const struct btf_header *hdr,
429 const char *raw_types, const char *str_sec,
430 const char *layout_sec, int token_fd);
431struct btf *bpf_object__sanitize_btf(struct bpf_object *obj, struct btf *orig_btf);
432int btf_load_into_kernel(struct btf *btf,
433 char *log_buf, size_t log_sz, __u32 log_level,
434 int token_fd);
435struct btf *btf_load_from_kernel(__u32 id, struct btf *base_btf, int token_fd);
436
437struct btf *btf_get_from_fd(int btf_fd, struct btf *base_btf);
438void btf_get_kernel_prefix_kind(enum bpf_attach_type attach_type,
439 const char **prefix, int *kind);
440
441struct btf_ext_info {
442 /*
443 * info points to the individual info section (e.g. func_info and
444 * line_info) from the .BTF.ext. It does not include the __u32 rec_size.
445 */
446 void *info;
447 __u32 rec_size;
448 __u32 len;
449 /* optional (maintained internally by libbpf) mapping between .BTF.ext
450 * section and corresponding ELF section. This is used to join
451 * information like CO-RE relocation records with corresponding BPF
452 * programs defined in ELF sections
453 */
454 __u32 *sec_idxs;
455 int sec_cnt;
456};
457
458#define for_each_btf_ext_sec(seg, sec) \
459 for (sec = (seg)->info; \
460 (void *)sec < (seg)->info + (seg)->len; \
461 sec = (void *)sec + sizeof(struct btf_ext_info_sec) + \
462 (seg)->rec_size * sec->num_info)
463
464#define for_each_btf_ext_rec(seg, sec, i, rec) \
465 for (i = 0, rec = (void *)&(sec)->data; \
466 i < (sec)->num_info; \
467 i++, rec = (void *)rec + (seg)->rec_size)
468
469/*
470 * The .BTF.ext ELF section layout defined as
471 * struct btf_ext_header
472 * func_info subsection
473 *
474 * The func_info subsection layout:
475 * record size for struct bpf_func_info in the func_info subsection
476 * struct btf_ext_info_sec for section #1
477 * a list of bpf_func_info records for section #1
478 * where struct bpf_func_info mimics one in include/uapi/linux/bpf.h
479 * but may not be identical
480 * struct btf_ext_info_sec for section #2
481 * a list of bpf_func_info records for section #2
482 * ......
483 *
484 * Note that the bpf_func_info record size in .BTF.ext may not
485 * be the same as the one defined in include/uapi/linux/bpf.h.
486 * The loader should ensure that record_size meets minimum
487 * requirement and pass the record as is to the kernel. The
488 * kernel will handle the func_info properly based on its contents.
489 */
490struct btf_ext_header {
491 __u16 magic;
492 __u8 version;
493 __u8 flags;
494 __u32 hdr_len;
495
496 /* All offsets are in bytes relative to the end of this header */
497 __u32 func_info_off;
498 __u32 func_info_len;
499 __u32 line_info_off;
500 __u32 line_info_len;
501
502 /* optional part of .BTF.ext header */
503 __u32 core_relo_off;
504 __u32 core_relo_len;
505};
506
507struct btf_ext {
508 union {
509 struct btf_ext_header *hdr;
510 void *data;
511 };
512 void *data_swapped;
513 bool swapped_endian;
514 struct btf_ext_info func_info;
515 struct btf_ext_info line_info;
516 struct btf_ext_info core_relo_info;
517 __u32 data_size;
518};
519
520struct btf_ext_info_sec {
521 __u32 sec_name_off;
522 __u32 num_info;
523 /* Followed by num_info * record_size number of bytes */
524 __u8 data[];
525};
526
527/* The minimum bpf_func_info checked by the loader */
528struct bpf_func_info_min {
529 __u32 insn_off;
530 __u32 type_id;
531};
532
533/* The minimum bpf_line_info checked by the loader */
534struct bpf_line_info_min {
535 __u32 insn_off;
536 __u32 file_name_off;
537 __u32 line_off;
538 __u32 line_col;
539};
540
541/* Functions to byte-swap info records */
542
543typedef void (*info_rec_bswap_fn)(void *);
544
545static inline void bpf_func_info_bswap(struct bpf_func_info *i)
546{
547 i->insn_off = bswap_32(i->insn_off);
548 i->type_id = bswap_32(i->type_id);
549}
550
551static inline void bpf_line_info_bswap(struct bpf_line_info *i)
552{
553 i->insn_off = bswap_32(i->insn_off);
554 i->file_name_off = bswap_32(i->file_name_off);
555 i->line_off = bswap_32(i->line_off);
556 i->line_col = bswap_32(i->line_col);
557}
558
559static inline void bpf_core_relo_bswap(struct bpf_core_relo *i)
560{
561 i->insn_off = bswap_32(i->insn_off);
562 i->type_id = bswap_32(i->type_id);
563 i->access_str_off = bswap_32(i->access_str_off);
564 i->kind = bswap_32(i->kind);
565}
566
567enum btf_field_iter_kind {
568 BTF_FIELD_ITER_IDS,
569 BTF_FIELD_ITER_STRS,
570};
571
572struct btf_field_desc {
573 /* once-per-type offsets */
574 int t_off_cnt, t_offs[2];
575 /* member struct size, or zero, if no members */
576 int m_sz;
577 /* repeated per-member offsets */
578 int m_off_cnt, m_offs[1];
579};
580
581struct btf_field_iter {
582 struct btf_field_desc desc;
583 void *p;
584 int m_idx;
585 int off_idx;
586 int vlen;
587};
588
589int btf_field_iter_init(struct btf_field_iter *it, struct btf_type *t, enum btf_field_iter_kind iter_kind);
590__u32 *btf_field_iter_next(struct btf_field_iter *it);
591
592typedef int (*type_id_visit_fn)(__u32 *type_id, void *ctx);
593typedef int (*str_off_visit_fn)(__u32 *str_off, void *ctx);
594int btf_ext_visit_type_ids(struct btf_ext *btf_ext, type_id_visit_fn visit, void *ctx);
595int btf_ext_visit_str_offs(struct btf_ext *btf_ext, str_off_visit_fn visit, void *ctx);
596__s32 btf__find_by_name_kind_own(const struct btf *btf, const char *type_name,
597 __u32 kind);
598
599/* handle direct returned errors */
600static inline int libbpf_err(int ret)
601{
602 if (ret < 0)
603 errno = -ret;
604 return ret;
605}
606
607/* handle errno-based (e.g., syscall or libc) errors according to libbpf's
608 * strict mode settings
609 */
610static inline int libbpf_err_errno(int ret)
611{
612 /* errno is already assumed to be set on error */
613 return ret < 0 ? -errno : ret;
614}
615
616/* handle error for pointer-returning APIs, err is assumed to be < 0 always */
617static inline void *libbpf_err_ptr(int err)
618{
619 /* set errno on error, this doesn't break anything */
620 errno = -err;
621 return NULL;
622}
623
624/* handle pointer-returning APIs' error handling */
625static inline void *libbpf_ptr(void *ret)
626{
627 /* set errno on error, this doesn't break anything */
628 if (IS_ERR(ret))
629 errno = -PTR_ERR(ret);
630
631 return IS_ERR(ret) ? NULL : ret;
632}
633
634static inline bool str_is_empty(const char *s)
635{
636 return !s || !s[0];
637}
638
639static inline bool is_ldimm64_insn(struct bpf_insn *insn)
640{
641 return insn->code == (BPF_LD | BPF_IMM | BPF_DW);
642}
643
644static inline void bpf_insn_bswap(struct bpf_insn *insn)
645{
646 __u8 tmp_reg = insn->dst_reg;
647
648 insn->dst_reg = insn->src_reg;
649 insn->src_reg = tmp_reg;
650 insn->off = bswap_16(insn->off);
651 insn->imm = bswap_32(insn->imm);
652}
653
654/* Unconditionally dup FD, ensuring it doesn't use [0, 2] range.
655 * Original FD is not closed or altered in any other way.
656 * Preserves original FD value, if it's invalid (negative).
657 */
658static inline int dup_good_fd(int fd)
659{
660 if (fd < 0)
661 return fd;
662 return fcntl(fd, F_DUPFD_CLOEXEC, 3);
663}
664
665/* if fd is stdin, stdout, or stderr, dup to a fd greater than 2
666 * Takes ownership of the fd passed in, and closes it if calling
667 * fcntl(fd, F_DUPFD_CLOEXEC, 3).
668 */
669static inline int ensure_good_fd(int fd)
670{
671 int old_fd = fd, saved_errno;
672
673 if (fd < 0)
674 return fd;
675 if (fd < 3) {
676 fd = dup_good_fd(fd);
677 saved_errno = errno;
678 close(old_fd);
679 errno = saved_errno;
680 if (fd < 0) {
681 pr_warn("failed to dup FD %d to FD > 2: %d\n", old_fd, -saved_errno);
682 errno = saved_errno;
683 }
684 }
685 return fd;
686}
687
688static inline int sys_dup3(int oldfd, int newfd, int flags)
689{
690 return syscall(__NR_dup3, oldfd, newfd, flags);
691}
692
693/* Some versions of Android don't provide memfd_create() in their libc
694 * implementation, so avoid complications and just go straight to Linux
695 * syscall.
696 */
697static inline int sys_memfd_create(const char *name, unsigned flags)
698{
699 return syscall(__NR_memfd_create, name, flags);
700}
701
702/* Point *fixed_fd* to the same file that *tmp_fd* points to.
703 * Regardless of success, *tmp_fd* is closed.
704 * Whatever *fixed_fd* pointed to is closed silently.
705 */
706static inline int reuse_fd(int fixed_fd, int tmp_fd)
707{
708 int err;
709
710 err = sys_dup3(tmp_fd, fixed_fd, O_CLOEXEC);
711 err = err < 0 ? -errno : 0;
712 close(tmp_fd); /* clean up temporary FD */
713 return err;
714}
715
716/* The following two functions are exposed to bpftool */
717int bpf_core_add_cands(struct bpf_core_cand *local_cand,
718 size_t local_essent_len,
719 const struct btf *targ_btf,
720 const char *targ_btf_name,
721 int targ_start_id,
722 struct bpf_core_cand_list *cands);
723void bpf_core_free_cands(struct bpf_core_cand_list *cands);
724
725struct usdt_manager *usdt_manager_new(struct bpf_object *obj);
726void usdt_manager_free(struct usdt_manager *man);
727struct bpf_link * usdt_manager_attach_usdt(struct usdt_manager *man,
728 const struct bpf_program *prog,
729 pid_t pid, const char *path,
730 const char *usdt_provider, const char *usdt_name,
731 __u64 usdt_cookie);
732
733static inline bool is_pow_of_2(size_t x)
734{
735 return x && (x & (x - 1)) == 0;
736}
737
738static inline __u32 ror32(__u32 v, int bits)
739{
740 return (v >> bits) | (v << (32 - bits));
741}
742
743#define PROG_LOAD_ATTEMPTS 5
744int sys_bpf_prog_load(union bpf_attr *attr, unsigned int size, int attempts);
745
746bool glob_match(const char *str, const char *pat);
747
748long elf_find_func_offset(Elf *elf, const char *binary_path, const char *name);
749long elf_find_func_offset_from_file(const char *binary_path, const char *name);
750
751struct elf_fd {
752 Elf *elf;
753 int fd;
754};
755
756int elf_open(const char *binary_path, struct elf_fd *elf_fd);
757void elf_close(struct elf_fd *elf_fd);
758
759int elf_resolve_syms_offsets(const char *binary_path, int cnt,
760 const char **syms, unsigned long **poffsets,
761 int st_type);
762int elf_resolve_pattern_offsets(const char *binary_path, const char *pattern,
763 unsigned long **poffsets, size_t *pcnt);
764
765int probe_fd(int fd);
766
767#define SHA256_DIGEST_LENGTH 32
768#define SHA256_DWORD_SIZE SHA256_DIGEST_LENGTH / sizeof(__u64)
769
770void libbpf_sha256(const void *data, size_t len, __u8 out[SHA256_DIGEST_LENGTH]);
771#endif /* __LIBBPF_LIBBPF_INTERNAL_H */