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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 <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);
253bool btf_type_is_traceable_func(const struct btf *btf, const struct btf_type *t);
254
255static inline enum btf_func_linkage btf_func_linkage(const struct btf_type *t)
256{
257 return (enum btf_func_linkage)(int)btf_vlen(t);
258}
259
260static inline __u32 btf_type_info(int kind, int vlen, int kflag)
261{
262 return (kflag << 31) | (kind << 24) | vlen;
263}
264
265enum map_def_parts {
266 MAP_DEF_MAP_TYPE = 0x001,
267 MAP_DEF_KEY_TYPE = 0x002,
268 MAP_DEF_KEY_SIZE = 0x004,
269 MAP_DEF_VALUE_TYPE = 0x008,
270 MAP_DEF_VALUE_SIZE = 0x010,
271 MAP_DEF_MAX_ENTRIES = 0x020,
272 MAP_DEF_MAP_FLAGS = 0x040,
273 MAP_DEF_NUMA_NODE = 0x080,
274 MAP_DEF_PINNING = 0x100,
275 MAP_DEF_INNER_MAP = 0x200,
276 MAP_DEF_MAP_EXTRA = 0x400,
277
278 MAP_DEF_ALL = 0x7ff, /* combination of all above */
279};
280
281struct btf_map_def {
282 enum map_def_parts parts;
283 __u32 map_type;
284 __u32 key_type_id;
285 __u32 key_size;
286 __u32 value_type_id;
287 __u32 value_size;
288 __u32 max_entries;
289 __u32 map_flags;
290 __u32 numa_node;
291 __u32 pinning;
292 __u64 map_extra;
293};
294
295int parse_btf_map_def(const char *map_name, struct btf *btf,
296 const struct btf_type *def_t, bool strict,
297 struct btf_map_def *map_def, struct btf_map_def *inner_def);
298
299void *libbpf_add_mem(void **data, size_t *cap_cnt, size_t elem_sz,
300 size_t cur_cnt, size_t max_cnt, size_t add_cnt);
301int libbpf_ensure_mem(void **data, size_t *cap_cnt, size_t elem_sz, size_t need_cnt);
302
303static inline bool libbpf_is_mem_zeroed(const char *p, ssize_t len)
304{
305 while (len > 0) {
306 if (*p)
307 return false;
308 p++;
309 len--;
310 }
311 return true;
312}
313
314static inline bool libbpf_validate_opts(const char *opts,
315 size_t opts_sz, size_t user_sz,
316 const char *type_name)
317{
318 if (user_sz < sizeof(size_t)) {
319 pr_warn("%s size (%zu) is too small\n", type_name, user_sz);
320 return false;
321 }
322 if (!libbpf_is_mem_zeroed(opts + opts_sz, (ssize_t)user_sz - opts_sz)) {
323 pr_warn("%s has non-zero extra bytes\n", type_name);
324 return false;
325 }
326 return true;
327}
328
329#define OPTS_VALID(opts, type) \
330 (!(opts) || libbpf_validate_opts((const char *)opts, \
331 offsetofend(struct type, \
332 type##__last_field), \
333 (opts)->sz, #type))
334#define OPTS_HAS(opts, field) \
335 ((opts) && opts->sz >= offsetofend(typeof(*(opts)), field))
336#define OPTS_GET(opts, field, fallback_value) \
337 (OPTS_HAS(opts, field) ? (opts)->field : fallback_value)
338#define OPTS_SET(opts, field, value) \
339 do { \
340 if (OPTS_HAS(opts, field)) \
341 (opts)->field = value; \
342 } while (0)
343
344#define OPTS_ZEROED(opts, last_nonzero_field) \
345({ \
346 ssize_t __off = offsetofend(typeof(*(opts)), last_nonzero_field); \
347 !(opts) || libbpf_is_mem_zeroed((const void *)opts + __off, \
348 (opts)->sz - __off); \
349})
350
351enum kern_feature_id {
352 /* v4.14: kernel support for program & map names. */
353 FEAT_PROG_NAME,
354 /* v5.2: kernel support for global data sections. */
355 FEAT_GLOBAL_DATA,
356 /* BTF support */
357 FEAT_BTF,
358 /* BTF_KIND_FUNC and BTF_KIND_FUNC_PROTO support */
359 FEAT_BTF_FUNC,
360 /* BTF_KIND_VAR and BTF_KIND_DATASEC support */
361 FEAT_BTF_DATASEC,
362 /* BTF_FUNC_GLOBAL is supported */
363 FEAT_BTF_GLOBAL_FUNC,
364 /* BPF_F_MMAPABLE is supported for arrays */
365 FEAT_ARRAY_MMAP,
366 /* kernel support for expected_attach_type in BPF_PROG_LOAD */
367 FEAT_EXP_ATTACH_TYPE,
368 /* bpf_probe_read_{kernel,user}[_str] helpers */
369 FEAT_PROBE_READ_KERN,
370 /* BPF_PROG_BIND_MAP is supported */
371 FEAT_PROG_BIND_MAP,
372 /* Kernel support for module BTFs */
373 FEAT_MODULE_BTF,
374 /* BTF_KIND_FLOAT support */
375 FEAT_BTF_FLOAT,
376 /* BPF perf link support */
377 FEAT_PERF_LINK,
378 /* BTF_KIND_DECL_TAG support */
379 FEAT_BTF_DECL_TAG,
380 /* BTF_KIND_TYPE_TAG support */
381 FEAT_BTF_TYPE_TAG,
382 /* memcg-based accounting for BPF maps and progs */
383 FEAT_MEMCG_ACCOUNT,
384 /* BPF cookie (bpf_get_attach_cookie() BPF helper) support */
385 FEAT_BPF_COOKIE,
386 /* BTF_KIND_ENUM64 support and BTF_KIND_ENUM kflag support */
387 FEAT_BTF_ENUM64,
388 /* Kernel uses syscall wrapper (CONFIG_ARCH_HAS_SYSCALL_WRAPPER) */
389 FEAT_SYSCALL_WRAPPER,
390 /* BPF multi-uprobe link support */
391 FEAT_UPROBE_MULTI_LINK,
392 /* Kernel supports arg:ctx tag (__arg_ctx) for global subprogs natively */
393 FEAT_ARG_CTX_TAG,
394 /* Kernel supports '?' at the front of datasec names */
395 FEAT_BTF_QMARK_DATASEC,
396 /* Kernel supports LDIMM64 imm offsets past 512 MiB. */
397 FEAT_LDIMM64_FULL_RANGE_OFF,
398 /* Kernel supports uprobe syscall */
399 FEAT_UPROBE_SYSCALL,
400 /* Kernel supports BTF layout information */
401 FEAT_BTF_LAYOUT,
402 /* Kernel supports BPF syscall common attributes */
403 FEAT_BPF_SYSCALL_COMMON_ATTRS,
404 /* Kernel supports percpu data */
405 FEAT_PERCPU_DATA,
406 __FEAT_CNT,
407};
408
409enum kern_feature_result {
410 FEAT_UNKNOWN = 0,
411 FEAT_SUPPORTED = 1,
412 FEAT_MISSING = 2,
413};
414
415struct kern_feature_cache {
416 enum kern_feature_result res[__FEAT_CNT];
417 int token_fd;
418};
419
420bool feat_supported(struct kern_feature_cache *cache, enum kern_feature_id feat_id);
421bool kernel_supports(const struct bpf_object *obj, enum kern_feature_id feat_id);
422void bpf_object_set_feat_cache(struct bpf_object *obj, struct kern_feature_cache *cache);
423
424int probe_kern_syscall_wrapper(int token_fd);
425int probe_memcg_account(int token_fd);
426int bump_rlimit_memlock(void);
427
428int parse_cpu_mask_str(const char *s, bool **mask, int *mask_sz);
429int parse_cpu_mask_file(const char *fcpu, bool **mask, int *mask_sz);
430int libbpf__load_raw_btf(const char *raw_types, size_t types_len,
431 const char *str_sec, size_t str_len,
432 int token_fd);
433int libbpf__load_raw_btf_hdr(const struct btf_header *hdr,
434 const char *raw_types, const char *str_sec,
435 const char *layout_sec, int token_fd);
436struct btf *bpf_object__sanitize_btf(struct bpf_object *obj, struct btf *orig_btf);
437int btf_load_into_kernel(struct btf *btf,
438 char *log_buf, size_t log_sz, __u32 log_level,
439 int token_fd);
440struct btf *btf_load_from_kernel(__u32 id, struct btf *base_btf, int token_fd);
441
442struct btf *btf_get_from_fd(int btf_fd, struct btf *base_btf);
443void btf_get_kernel_prefix_kind(enum bpf_attach_type attach_type,
444 const char **prefix, int *kind);
445
446struct btf_ext_info {
447 /*
448 * info points to the individual info section (e.g. func_info and
449 * line_info) from the .BTF.ext. It does not include the __u32 rec_size.
450 */
451 void *info;
452 __u32 rec_size;
453 __u32 len;
454 /* optional (maintained internally by libbpf) mapping between .BTF.ext
455 * section and corresponding ELF section. This is used to join
456 * information like CO-RE relocation records with corresponding BPF
457 * programs defined in ELF sections
458 */
459 __u32 *sec_idxs;
460 int sec_cnt;
461};
462
463#define for_each_btf_ext_sec(seg, sec) \
464 for (sec = (seg)->info; \
465 (void *)sec < (seg)->info + (seg)->len; \
466 sec = (void *)sec + sizeof(struct btf_ext_info_sec) + \
467 (seg)->rec_size * sec->num_info)
468
469#define for_each_btf_ext_rec(seg, sec, i, rec) \
470 for (i = 0, rec = (void *)&(sec)->data; \
471 i < (sec)->num_info; \
472 i++, rec = (void *)rec + (seg)->rec_size)
473
474/*
475 * The .BTF.ext ELF section layout defined as
476 * struct btf_ext_header
477 * func_info subsection
478 *
479 * The func_info subsection layout:
480 * record size for struct bpf_func_info in the func_info subsection
481 * struct btf_ext_info_sec for section #1
482 * a list of bpf_func_info records for section #1
483 * where struct bpf_func_info mimics one in include/uapi/linux/bpf.h
484 * but may not be identical
485 * struct btf_ext_info_sec for section #2
486 * a list of bpf_func_info records for section #2
487 * ......
488 *
489 * Note that the bpf_func_info record size in .BTF.ext may not
490 * be the same as the one defined in include/uapi/linux/bpf.h.
491 * The loader should ensure that record_size meets minimum
492 * requirement and pass the record as is to the kernel. The
493 * kernel will handle the func_info properly based on its contents.
494 */
495struct btf_ext_header {
496 __u16 magic;
497 __u8 version;
498 __u8 flags;
499 __u32 hdr_len;
500
501 /* All offsets are in bytes relative to the end of this header */
502 __u32 func_info_off;
503 __u32 func_info_len;
504 __u32 line_info_off;
505 __u32 line_info_len;
506
507 /* optional part of .BTF.ext header */
508 __u32 core_relo_off;
509 __u32 core_relo_len;
510};
511
512struct btf_ext {
513 union {
514 struct btf_ext_header *hdr;
515 void *data;
516 };
517 void *data_swapped;
518 bool swapped_endian;
519 struct btf_ext_info func_info;
520 struct btf_ext_info line_info;
521 struct btf_ext_info core_relo_info;
522 __u32 data_size;
523};
524
525struct btf_ext_info_sec {
526 __u32 sec_name_off;
527 __u32 num_info;
528 /* Followed by num_info * record_size number of bytes */
529 __u8 data[];
530};
531
532/* The minimum bpf_func_info checked by the loader */
533struct bpf_func_info_min {
534 __u32 insn_off;
535 __u32 type_id;
536};
537
538/* The minimum bpf_line_info checked by the loader */
539struct bpf_line_info_min {
540 __u32 insn_off;
541 __u32 file_name_off;
542 __u32 line_off;
543 __u32 line_col;
544};
545
546/* Functions to byte-swap info records */
547
548typedef void (*info_rec_bswap_fn)(void *);
549
550static inline void bpf_func_info_bswap(struct bpf_func_info *i)
551{
552 i->insn_off = bswap_32(i->insn_off);
553 i->type_id = bswap_32(i->type_id);
554}
555
556static inline void bpf_line_info_bswap(struct bpf_line_info *i)
557{
558 i->insn_off = bswap_32(i->insn_off);
559 i->file_name_off = bswap_32(i->file_name_off);
560 i->line_off = bswap_32(i->line_off);
561 i->line_col = bswap_32(i->line_col);
562}
563
564static inline void bpf_core_relo_bswap(struct bpf_core_relo *i)
565{
566 i->insn_off = bswap_32(i->insn_off);
567 i->type_id = bswap_32(i->type_id);
568 i->access_str_off = bswap_32(i->access_str_off);
569 i->kind = bswap_32(i->kind);
570}
571
572enum btf_field_iter_kind {
573 BTF_FIELD_ITER_IDS,
574 BTF_FIELD_ITER_STRS,
575};
576
577struct btf_field_desc {
578 /* once-per-type offsets */
579 int t_off_cnt, t_offs[2];
580 /* member struct size, or zero, if no members */
581 int m_sz;
582 /* repeated per-member offsets */
583 int m_off_cnt, m_offs[1];
584};
585
586struct btf_field_iter {
587 struct btf_field_desc desc;
588 void *p;
589 int m_idx;
590 int off_idx;
591 int vlen;
592};
593
594int btf_field_iter_init(struct btf_field_iter *it, struct btf_type *t, enum btf_field_iter_kind iter_kind);
595__u32 *btf_field_iter_next(struct btf_field_iter *it);
596
597typedef int (*type_id_visit_fn)(__u32 *type_id, void *ctx);
598typedef int (*str_off_visit_fn)(__u32 *str_off, void *ctx);
599int btf_ext_visit_type_ids(struct btf_ext *btf_ext, type_id_visit_fn visit, void *ctx);
600int btf_ext_visit_str_offs(struct btf_ext *btf_ext, str_off_visit_fn visit, void *ctx);
601
602/* handle direct returned errors */
603static inline int libbpf_err(int ret)
604{
605 if (ret < 0)
606 errno = -ret;
607 return ret;
608}
609
610/* handle errno-based (e.g., syscall or libc) errors according to libbpf's
611 * strict mode settings
612 */
613static inline int libbpf_err_errno(int ret)
614{
615 /* errno is already assumed to be set on error */
616 return ret < 0 ? -errno : ret;
617}
618
619/* handle error for pointer-returning APIs, err is assumed to be < 0 always */
620static inline void *libbpf_err_ptr(int err)
621{
622 /* set errno on error, this doesn't break anything */
623 errno = -err;
624 return NULL;
625}
626
627/* handle pointer-returning APIs' error handling */
628static inline void *libbpf_ptr(void *ret)
629{
630 /* set errno on error, this doesn't break anything */
631 if (IS_ERR(ret))
632 errno = -PTR_ERR(ret);
633
634 return IS_ERR(ret) ? NULL : ret;
635}
636
637static inline bool str_is_empty(const char *s)
638{
639 return !s || !s[0];
640}
641
642static inline bool is_ldimm64_insn(struct bpf_insn *insn)
643{
644 return insn->code == (BPF_LD | BPF_IMM | BPF_DW);
645}
646
647static inline void bpf_insn_bswap(struct bpf_insn *insn)
648{
649 __u8 tmp_reg = insn->dst_reg;
650
651 insn->dst_reg = insn->src_reg;
652 insn->src_reg = tmp_reg;
653 insn->off = bswap_16(insn->off);
654 insn->imm = bswap_32(insn->imm);
655}
656
657/* Unconditionally dup FD, ensuring it doesn't use [0, 2] range.
658 * Original FD is not closed or altered in any other way.
659 * Preserves original FD value, if it's invalid (negative).
660 */
661static inline int dup_good_fd(int fd)
662{
663 if (fd < 0)
664 return fd;
665 return fcntl(fd, F_DUPFD_CLOEXEC, 3);
666}
667
668/* if fd is stdin, stdout, or stderr, dup to a fd greater than 2
669 * Takes ownership of the fd passed in, and closes it if calling
670 * fcntl(fd, F_DUPFD_CLOEXEC, 3).
671 */
672static inline int ensure_good_fd(int fd)
673{
674 int old_fd = fd, saved_errno;
675
676 if (fd < 0)
677 return fd;
678 if (fd < 3) {
679 fd = dup_good_fd(fd);
680 saved_errno = errno;
681 close(old_fd);
682 errno = saved_errno;
683 if (fd < 0) {
684 pr_warn("failed to dup FD %d to FD > 2: %d\n", old_fd, -saved_errno);
685 errno = saved_errno;
686 }
687 }
688 return fd;
689}
690
691static inline int sys_dup3(int oldfd, int newfd, int flags)
692{
693 return syscall(__NR_dup3, oldfd, newfd, flags);
694}
695
696/* Some versions of Android don't provide memfd_create() in their libc
697 * implementation, so avoid complications and just go straight to Linux
698 * syscall.
699 */
700static inline int sys_memfd_create(const char *name, unsigned flags)
701{
702 return syscall(__NR_memfd_create, name, flags);
703}
704
705/* Point *fixed_fd* to the same file that *tmp_fd* points to.
706 * Regardless of success, *tmp_fd* is closed.
707 * Whatever *fixed_fd* pointed to is closed silently.
708 */
709static inline int reuse_fd(int fixed_fd, int tmp_fd)
710{
711 int err;
712
713 err = sys_dup3(tmp_fd, fixed_fd, O_CLOEXEC);
714 err = err < 0 ? -errno : 0;
715 close(tmp_fd); /* clean up temporary FD */
716 return err;
717}
718
719/* The following two functions are exposed to bpftool */
720int bpf_core_add_cands(struct bpf_core_cand *local_cand,
721 size_t local_essent_len,
722 const struct btf *targ_btf,
723 const char *targ_btf_name,
724 int targ_start_id,
725 struct bpf_core_cand_list *cands);
726void bpf_core_free_cands(struct bpf_core_cand_list *cands);
727
728struct usdt_manager *usdt_manager_new(struct bpf_object *obj);
729void usdt_manager_free(struct usdt_manager *man);
730struct bpf_link * usdt_manager_attach_usdt(struct usdt_manager *man,
731 const struct bpf_program *prog,
732 pid_t pid, const char *path,
733 const char *usdt_provider, const char *usdt_name,
734 __u64 usdt_cookie);
735
736static inline bool is_pow_of_2(size_t x)
737{
738 return x && (x & (x - 1)) == 0;
739}
740
741static inline __u32 ror32(__u32 v, int bits)
742{
743 return (v >> bits) | (v << (32 - bits));
744}
745
746#define PROG_LOAD_ATTEMPTS 5
747int sys_bpf_prog_load(union bpf_attr *attr, unsigned int size, int attempts);
748
749bool glob_match(const char *str, const char *pat);
750
751long elf_find_func_offset(Elf *elf, const char *binary_path, const char *name);
752long elf_find_func_offset_from_file(const char *binary_path, const char *name);
753
754struct elf_fd {
755 Elf *elf;
756 int fd;
757};
758
759int elf_open(const char *binary_path, struct elf_fd *elf_fd);
760void elf_close(struct elf_fd *elf_fd);
761
762int elf_resolve_syms_offsets(const char *binary_path, int cnt,
763 const char **syms, unsigned long **poffsets,
764 int st_type);
765int elf_resolve_pattern_offsets(const char *binary_path, const char *pattern,
766 unsigned long **poffsets, size_t *pcnt);
767
768int probe_fd(int fd);
769
770#define SHA256_DIGEST_LENGTH 32
771
772void libbpf_sha256(const void *data, size_t len, __u8 out[SHA256_DIGEST_LENGTH]);
773int probe_sys_bpf_ext(void);
774#endif /* __LIBBPF_LIBBPF_INTERNAL_H */