summaryrefslogtreecommitdiff
path: root/tools/lib/bpf/libbpf_internal.h
blob: a0dcfb82e455d7c7f3dc8ed0b944ee37dad03324 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */

/*
 * Internal libbpf helpers.
 *
 * Copyright (c) 2019 Facebook
 */

#ifndef __LIBBPF_LIBBPF_INTERNAL_H
#define __LIBBPF_LIBBPF_INTERNAL_H

#include <stdlib.h>
#include <limits.h>
#include <errno.h>
#include <linux/err.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/syscall.h>
#include <libelf.h>
#include "relo_core.h"

/* Android's libc doesn't support AT_EACCESS in faccessat() implementation
 * ([0]), and just returns -EINVAL even if file exists and is accessible.
 * See [1] for issues caused by this.
 *
 * So just redefine it to 0 on Android.
 *
 * [0] https://android.googlesource.com/platform/bionic/+/refs/heads/android13-release/libc/bionic/faccessat.cpp#50
 * [1] https://github.com/libbpf/libbpf-bootstrap/issues/250#issuecomment-1911324250
 */
#ifdef __ANDROID__
#undef AT_EACCESS
#define AT_EACCESS 0
#endif

/* make sure libbpf doesn't use kernel-only integer typedefs */
#pragma GCC poison u8 u16 u32 u64 s8 s16 s32 s64

/* prevent accidental re-addition of reallocarray() */
#pragma GCC poison reallocarray

#include "libbpf.h"
#include "btf.h"

#ifndef EM_BPF
#define EM_BPF 247
#endif

#ifndef R_BPF_64_64
#define R_BPF_64_64 1
#endif
#ifndef R_BPF_64_ABS64
#define R_BPF_64_ABS64 2
#endif
#ifndef R_BPF_64_ABS32
#define R_BPF_64_ABS32 3
#endif
#ifndef R_BPF_64_32
#define R_BPF_64_32 10
#endif

#ifndef SHT_LLVM_ADDRSIG
#define SHT_LLVM_ADDRSIG 0x6FFF4C03
#endif

/* if libelf is old and doesn't support mmap(), fall back to read() */
#ifndef ELF_C_READ_MMAP
#define ELF_C_READ_MMAP ELF_C_READ
#endif

/* Older libelf all end up in this expression, for both 32 and 64 bit */
#ifndef ELF64_ST_VISIBILITY
#define ELF64_ST_VISIBILITY(o) ((o) & 0x03)
#endif

#define BTF_INFO_ENC(kind, kind_flag, vlen) \
	((!!(kind_flag) << 31) | ((kind) << 24) | ((vlen) & BTF_MAX_VLEN))
#define BTF_TYPE_ENC(name, info, size_or_type) (name), (info), (size_or_type)
#define BTF_INT_ENC(encoding, bits_offset, nr_bits) \
	((encoding) << 24 | (bits_offset) << 16 | (nr_bits))
#define BTF_TYPE_INT_ENC(name, encoding, bits_offset, bits, sz) \
	BTF_TYPE_ENC(name, BTF_INFO_ENC(BTF_KIND_INT, 0, 0), sz), \
	BTF_INT_ENC(encoding, bits_offset, bits)
#define BTF_MEMBER_ENC(name, type, bits_offset) (name), (type), (bits_offset)
#define BTF_PARAM_ENC(name, type) (name), (type)
#define BTF_VAR_SECINFO_ENC(type, offset, size) (type), (offset), (size)
#define BTF_TYPE_FLOAT_ENC(name, sz) \
	BTF_TYPE_ENC(name, BTF_INFO_ENC(BTF_KIND_FLOAT, 0, 0), sz)
#define BTF_TYPE_DECL_TAG_ENC(value, type, component_idx) \
	BTF_TYPE_ENC(value, BTF_INFO_ENC(BTF_KIND_DECL_TAG, 0, 0), type), (component_idx)
#define BTF_TYPE_TYPE_TAG_ENC(value, type) \
	BTF_TYPE_ENC(value, BTF_INFO_ENC(BTF_KIND_TYPE_TAG, 0, 0), type)

#ifndef likely
#define likely(x) __builtin_expect(!!(x), 1)
#endif
#ifndef unlikely
#define unlikely(x) __builtin_expect(!!(x), 0)
#endif
#ifndef min
# define min(x, y) ((x) < (y) ? (x) : (y))
#endif
#ifndef max
# define max(x, y) ((x) < (y) ? (y) : (x))
#endif
#ifndef offsetofend
# define offsetofend(TYPE, FIELD) \
	(offsetof(TYPE, FIELD) + sizeof(((TYPE *)0)->FIELD))
#endif
#ifndef __alias
#define __alias(symbol) __attribute__((alias(#symbol)))
#endif

/* Check whether a string `str` has prefix `pfx`, regardless if `pfx` is
 * a string literal known at compilation time or char * pointer known only at
 * runtime.
 */
#define str_has_pfx(str, pfx) \
	(strncmp(str, pfx, __builtin_constant_p(pfx) ? sizeof(pfx) - 1 : strlen(pfx)) == 0)

/* suffix check */
static inline bool str_has_sfx(const char *str, const char *sfx)
{
	size_t str_len = strlen(str);
	size_t sfx_len = strlen(sfx);

	if (sfx_len > str_len)
		return false;
	return strcmp(str + str_len - sfx_len, sfx) == 0;
}

/* Symbol versioning is different between static and shared library.
 * Properly versioned symbols are needed for shared library, but
 * only the symbol of the new version is needed for static library.
 * Starting with GNU C 10, use symver attribute instead of .symver assembler
 * directive, which works better with GCC LTO builds.
 */
#if defined(SHARED) && defined(__GNUC__) && __GNUC__ >= 10

#define DEFAULT_VERSION(internal_name, api_name, version) \
	__attribute__((symver(#api_name "@@" #version)))
#define COMPAT_VERSION(internal_name, api_name, version) \
	__attribute__((symver(#api_name "@" #version)))

#elif defined(SHARED)

#define COMPAT_VERSION(internal_name, api_name, version) \
	asm(".symver " #internal_name "," #api_name "@" #version);
#define DEFAULT_VERSION(internal_name, api_name, version) \
	asm(".symver " #internal_name "," #api_name "@@" #version);

#else /* !SHARED */

#define COMPAT_VERSION(internal_name, api_name, version)
#define DEFAULT_VERSION(internal_name, api_name, version) \
	extern typeof(internal_name) api_name \
	__attribute__((alias(#internal_name)));

#endif

extern void libbpf_print(enum libbpf_print_level level,
			 const char *format, ...)
	__attribute__((format(printf, 2, 3)));

#define __pr(level, fmt, ...)	\
do {				\
	libbpf_print(level, "libbpf: " fmt, ##__VA_ARGS__);	\
} while (0)

#define pr_warn(fmt, ...)	__pr(LIBBPF_WARN, fmt, ##__VA_ARGS__)
#define pr_info(fmt, ...)	__pr(LIBBPF_INFO, fmt, ##__VA_ARGS__)
#define pr_debug(fmt, ...)	__pr(LIBBPF_DEBUG, fmt, ##__VA_ARGS__)

#ifndef __has_builtin
#define __has_builtin(x) 0
#endif

struct bpf_link {
	int (*detach)(struct bpf_link *link);
	void (*dealloc)(struct bpf_link *link);
	char *pin_path;		/* NULL, if not pinned */
	int fd;			/* hook FD, -1 if not applicable */
	bool disconnected;
};

/*
 * Re-implement glibc's reallocarray() for libbpf internal-only use.
 * reallocarray(), unfortunately, is not available in all versions of glibc,
 * so requires extra feature detection and using reallocarray() stub from
 * <tools/libc_compat.h> and COMPAT_NEED_REALLOCARRAY. All this complicates
 * build of libbpf unnecessarily and is just a maintenance burden. Instead,
 * it's trivial to implement libbpf-specific internal version and use it
 * throughout libbpf.
 */
static inline void *libbpf_reallocarray(void *ptr, size_t nmemb, size_t size)
{
	size_t total;

#if __has_builtin(__builtin_mul_overflow)
	if (unlikely(__builtin_mul_overflow(nmemb, size, &total)))
		return NULL;
#else
	if (size == 0 || nmemb > ULONG_MAX / size)
		return NULL;
	total = nmemb * size;
#endif
	return realloc(ptr, total);
}

/* Copy up to sz - 1 bytes from zero-terminated src string and ensure that dst
 * is zero-terminated string no matter what (unless sz == 0, in which case
 * it's a no-op). It's conceptually close to FreeBSD's strlcpy(), but differs
 * in what is returned. Given this is internal helper, it's trivial to extend
 * this, when necessary. Use this instead of strncpy inside libbpf source code.
 */
static inline void libbpf_strlcpy(char *dst, const char *src, size_t sz)
{
	size_t i;

	if (sz == 0)
		return;

	sz--;
	for (i = 0; i < sz && src[i]; i++)
		dst[i] = src[i];
	dst[i] = '\0';
}

__u32 get_kernel_version(void);

struct btf;
struct btf_type;

struct btf_type *btf_type_by_id(const struct btf *btf, __u32 type_id);
const char *btf_kind_str(const struct btf_type *t);
const struct btf_type *skip_mods_and_typedefs(const struct btf *btf, __u32 id, __u32 *res_id);

static inline enum btf_func_linkage btf_func_linkage(const struct btf_type *t)
{
	return (enum btf_func_linkage)(int)btf_vlen(t);
}

static inline __u32 btf_type_info(int kind, int vlen, int kflag)
{
	return (kflag << 31) | (kind << 24) | vlen;
}

enum map_def_parts {
	MAP_DEF_MAP_TYPE	= 0x001,
	MAP_DEF_KEY_TYPE	= 0x002,
	MAP_DEF_KEY_SIZE	= 0x004,
	MAP_DEF_VALUE_TYPE	= 0x008,
	MAP_DEF_VALUE_SIZE	= 0x010,
	MAP_DEF_MAX_ENTRIES	= 0x020,
	MAP_DEF_MAP_FLAGS	= 0x040,
	MAP_DEF_NUMA_NODE	= 0x080,
	MAP_DEF_PINNING		= 0x100,
	MAP_DEF_INNER_MAP	= 0x200,
	MAP_DEF_MAP_EXTRA	= 0x400,

	MAP_DEF_ALL		= 0x7ff, /* combination of all above */
};

struct btf_map_def {
	enum map_def_parts parts;
	__u32 map_type;
	__u32 key_type_id;
	__u32 key_size;
	__u32 value_type_id;
	__u32 value_size;
	__u32 max_entries;
	__u32 map_flags;
	__u32 numa_node;
	__u32 pinning;
	__u64 map_extra;
};

int parse_btf_map_def(const char *map_name, struct btf *btf,
		      const struct btf_type *def_t, bool strict,
		      struct btf_map_def *map_def, struct btf_map_def *inner_def);

void *libbpf_add_mem(void **data, size_t *cap_cnt, size_t elem_sz,
		     size_t cur_cnt, size_t max_cnt, size_t add_cnt);
int libbpf_ensure_mem(void **data, size_t *cap_cnt, size_t elem_sz, size_t need_cnt);

static inline bool libbpf_is_mem_zeroed(const char *p, ssize_t len)
{
	while (len > 0) {
		if (*p)
			return false;
		p++;
		len--;
	}
	return true;
}

static inline bool libbpf_validate_opts(const char *opts,
					size_t opts_sz, size_t user_sz,
					const char *type_name)
{
	if (user_sz < sizeof(size_t)) {
		pr_warn("%s size (%zu) is too small\n", type_name, user_sz);
		return false;
	}
	if (!libbpf_is_mem_zeroed(opts + opts_sz, (ssize_t)user_sz - opts_sz)) {
		pr_warn("%s has non-zero extra bytes\n", type_name);
		return false;
	}
	return true;
}

#define OPTS_VALID(opts, type)						      \
	(!(opts) || libbpf_validate_opts((const char *)opts,		      \
					 offsetofend(struct type,	      \
						     type##__last_field),     \
					 (opts)->sz, #type))
#define OPTS_HAS(opts, field) \
	((opts) && opts->sz >= offsetofend(typeof(*(opts)), field))
#define OPTS_GET(opts, field, fallback_value) \
	(OPTS_HAS(opts, field) ? (opts)->field : fallback_value)
#define OPTS_SET(opts, field, value)		\
	do {					\
		if (OPTS_HAS(opts, field))	\
			(opts)->field = value;	\
	} while (0)

#define OPTS_ZEROED(opts, last_nonzero_field)				      \
({									      \
	ssize_t __off = offsetofend(typeof(*(opts)), last_nonzero_field);     \
	!(opts) || libbpf_is_mem_zeroed((const void *)opts + __off,	      \
					(opts)->sz - __off);		      \
})

enum kern_feature_id {
	/* v4.14: kernel support for program & map names. */
	FEAT_PROG_NAME,
	/* v5.2: kernel support for global data sections. */
	FEAT_GLOBAL_DATA,
	/* BTF support */
	FEAT_BTF,
	/* BTF_KIND_FUNC and BTF_KIND_FUNC_PROTO support */
	FEAT_BTF_FUNC,
	/* BTF_KIND_VAR and BTF_KIND_DATASEC support */
	FEAT_BTF_DATASEC,
	/* BTF_FUNC_GLOBAL is supported */
	FEAT_BTF_GLOBAL_FUNC,
	/* BPF_F_MMAPABLE is supported for arrays */
	FEAT_ARRAY_MMAP,
	/* kernel support for expected_attach_type in BPF_PROG_LOAD */
	FEAT_EXP_ATTACH_TYPE,
	/* bpf_probe_read_{kernel,user}[_str] helpers */
	FEAT_PROBE_READ_KERN,
	/* BPF_PROG_BIND_MAP is supported */
	FEAT_PROG_BIND_MAP,
	/* Kernel support for module BTFs */
	FEAT_MODULE_BTF,
	/* BTF_KIND_FLOAT support */
	FEAT_BTF_FLOAT,
	/* BPF perf link support */
	FEAT_PERF_LINK,
	/* BTF_KIND_DECL_TAG support */
	FEAT_BTF_DECL_TAG,
	/* BTF_KIND_TYPE_TAG support */
	FEAT_BTF_TYPE_TAG,
	/* memcg-based accounting for BPF maps and progs */
	FEAT_MEMCG_ACCOUNT,
	/* BPF cookie (bpf_get_attach_cookie() BPF helper) support */
	FEAT_BPF_COOKIE,
	/* BTF_KIND_ENUM64 support and BTF_KIND_ENUM kflag support */
	FEAT_BTF_ENUM64,
	/* Kernel uses syscall wrapper (CONFIG_ARCH_HAS_SYSCALL_WRAPPER) */
	FEAT_SYSCALL_WRAPPER,
	/* BPF multi-uprobe link support */
	FEAT_UPROBE_MULTI_LINK,
	/* Kernel supports arg:ctx tag (__arg_ctx) for global subprogs natively */
	FEAT_ARG_CTX_TAG,
	/* Kernel supports '?' at the front of datasec names */
	FEAT_BTF_QMARK_DATASEC,
	__FEAT_CNT,
};

enum kern_feature_result {
	FEAT_UNKNOWN = 0,
	FEAT_SUPPORTED = 1,
	FEAT_MISSING = 2,
};

struct kern_feature_cache {
	enum kern_feature_result res[__FEAT_CNT];
	int token_fd;
};

bool feat_supported(struct kern_feature_cache *cache, enum kern_feature_id feat_id);
bool kernel_supports(const struct bpf_object *obj, enum kern_feature_id feat_id);

int probe_kern_syscall_wrapper(int token_fd);
int probe_memcg_account(int token_fd);
int bump_rlimit_memlock(void);

int parse_cpu_mask_str(const char *s, bool **mask, int *mask_sz);
int parse_cpu_mask_file(const char *fcpu, bool **mask, int *mask_sz);
int libbpf__load_raw_btf(const char *raw_types, size_t types_len,
			 const char *str_sec, size_t str_len,
			 int token_fd);
int btf_load_into_kernel(struct btf *btf,
			 char *log_buf, size_t log_sz, __u32 log_level,
			 int token_fd);

struct btf *btf_get_from_fd(int btf_fd, struct btf *base_btf);
void btf_get_kernel_prefix_kind(enum bpf_attach_type attach_type,
				const char **prefix, int *kind);

struct btf_ext_info {
	/*
	 * info points to the individual info section (e.g. func_info and
	 * line_info) from the .BTF.ext. It does not include the __u32 rec_size.
	 */
	void *info;
	__u32 rec_size;
	__u32 len;
	/* optional (maintained internally by libbpf) mapping between .BTF.ext
	 * section and corresponding ELF section. This is used to join
	 * information like CO-RE relocation records with corresponding BPF
	 * programs defined in ELF sections
	 */
	__u32 *sec_idxs;
	int sec_cnt;
};

#define for_each_btf_ext_sec(seg, sec)					\
	for (sec = (seg)->info;						\
	     (void *)sec < (seg)->info + (seg)->len;			\
	     sec = (void *)sec + sizeof(struct btf_ext_info_sec) +	\
		   (seg)->rec_size * sec->num_info)

#define for_each_btf_ext_rec(seg, sec, i, rec)				\
	for (i = 0, rec = (void *)&(sec)->data;				\
	     i < (sec)->num_info;					\
	     i++, rec = (void *)rec + (seg)->rec_size)

/*
 * The .BTF.ext ELF section layout defined as
 *   struct btf_ext_header
 *   func_info subsection
 *
 * The func_info subsection layout:
 *   record size for struct bpf_func_info in the func_info subsection
 *   struct btf_sec_func_info for section #1
 *   a list of bpf_func_info records for section #1
 *     where struct bpf_func_info mimics one in include/uapi/linux/bpf.h
 *     but may not be identical
 *   struct btf_sec_func_info for section #2
 *   a list of bpf_func_info records for section #2
 *   ......
 *
 * Note that the bpf_func_info record size in .BTF.ext may not
 * be the same as the one defined in include/uapi/linux/bpf.h.
 * The loader should ensure that record_size meets minimum
 * requirement and pass the record as is to the kernel. The
 * kernel will handle the func_info properly based on its contents.
 */
struct btf_ext_header {
	__u16	magic;
	__u8	version;
	__u8	flags;
	__u32	hdr_len;

	/* All offsets are in bytes relative to the end of this header */
	__u32	func_info_off;
	__u32	func_info_len;
	__u32	line_info_off;
	__u32	line_info_len;

	/* optional part of .BTF.ext header */
	__u32	core_relo_off;
	__u32	core_relo_len;
};

struct btf_ext {
	union {
		struct btf_ext_header *hdr;
		void *data;
	};
	struct btf_ext_info func_info;
	struct btf_ext_info line_info;
	struct btf_ext_info core_relo_info;
	__u32 data_size;
};

struct btf_ext_info_sec {
	__u32	sec_name_off;
	__u32	num_info;
	/* Followed by num_info * record_size number of bytes */
	__u8	data[];
};

/* The minimum bpf_func_info checked by the loader */
struct bpf_func_info_min {
	__u32   insn_off;
	__u32   type_id;
};

/* The minimum bpf_line_info checked by the loader */
struct bpf_line_info_min {
	__u32	insn_off;
	__u32	file_name_off;
	__u32	line_off;
	__u32	line_col;
};


typedef int (*type_id_visit_fn)(__u32 *type_id, void *ctx);
typedef int (*str_off_visit_fn)(__u32 *str_off, void *ctx);
int btf_type_visit_type_ids(struct btf_type *t, type_id_visit_fn visit, void *ctx);
int btf_type_visit_str_offs(struct btf_type *t, str_off_visit_fn visit, void *ctx);
int btf_ext_visit_type_ids(struct btf_ext *btf_ext, type_id_visit_fn visit, void *ctx);
int btf_ext_visit_str_offs(struct btf_ext *btf_ext, str_off_visit_fn visit, void *ctx);
__s32 btf__find_by_name_kind_own(const struct btf *btf, const char *type_name,
				 __u32 kind);

/* handle direct returned errors */
static inline int libbpf_err(int ret)
{
	if (ret < 0)
		errno = -ret;
	return ret;
}

/* handle errno-based (e.g., syscall or libc) errors according to libbpf's
 * strict mode settings
 */
static inline int libbpf_err_errno(int ret)
{
	/* errno is already assumed to be set on error */
	return ret < 0 ? -errno : ret;
}

/* handle error for pointer-returning APIs, err is assumed to be < 0 always */
static inline void *libbpf_err_ptr(int err)
{
	/* set errno on error, this doesn't break anything */
	errno = -err;
	return NULL;
}

/* handle pointer-returning APIs' error handling */
static inline void *libbpf_ptr(void *ret)
{
	/* set errno on error, this doesn't break anything */
	if (IS_ERR(ret))
		errno = -PTR_ERR(ret);

	return IS_ERR(ret) ? NULL : ret;
}

static inline bool str_is_empty(const char *s)
{
	return !s || !s[0];
}

static inline bool is_ldimm64_insn(struct bpf_insn *insn)
{
	return insn->code == (BPF_LD | BPF_IMM | BPF_DW);
}

/* Unconditionally dup FD, ensuring it doesn't use [0, 2] range.
 * Original FD is not closed or altered in any other way.
 * Preserves original FD value, if it's invalid (negative).
 */
static inline int dup_good_fd(int fd)
{
	if (fd < 0)
		return fd;
	return fcntl(fd, F_DUPFD_CLOEXEC, 3);
}

/* if fd is stdin, stdout, or stderr, dup to a fd greater than 2
 * Takes ownership of the fd passed in, and closes it if calling
 * fcntl(fd, F_DUPFD_CLOEXEC, 3).
 */
static inline int ensure_good_fd(int fd)
{
	int old_fd = fd, saved_errno;

	if (fd < 0)
		return fd;
	if (fd < 3) {
		fd = dup_good_fd(fd);
		saved_errno = errno;
		close(old_fd);
		errno = saved_errno;
		if (fd < 0) {
			pr_warn("failed to dup FD %d to FD > 2: %d\n", old_fd, -saved_errno);
			errno = saved_errno;
		}
	}
	return fd;
}

static inline int sys_dup2(int oldfd, int newfd)
{
#ifdef __NR_dup2
	return syscall(__NR_dup2, oldfd, newfd);
#else
	return syscall(__NR_dup3, oldfd, newfd, 0);
#endif
}

/* Point *fixed_fd* to the same file that *tmp_fd* points to.
 * Regardless of success, *tmp_fd* is closed.
 * Whatever *fixed_fd* pointed to is closed silently.
 */
static inline int reuse_fd(int fixed_fd, int tmp_fd)
{
	int err;

	err = sys_dup2(tmp_fd, fixed_fd);
	err = err < 0 ? -errno : 0;
	close(tmp_fd); /* clean up temporary FD */
	return err;
}

/* The following two functions are exposed to bpftool */
int bpf_core_add_cands(struct bpf_core_cand *local_cand,
		       size_t local_essent_len,
		       const struct btf *targ_btf,
		       const char *targ_btf_name,
		       int targ_start_id,
		       struct bpf_core_cand_list *cands);
void bpf_core_free_cands(struct bpf_core_cand_list *cands);

struct usdt_manager *usdt_manager_new(struct bpf_object *obj);
void usdt_manager_free(struct usdt_manager *man);
struct bpf_link * usdt_manager_attach_usdt(struct usdt_manager *man,
					   const struct bpf_program *prog,
					   pid_t pid, const char *path,
					   const char *usdt_provider, const char *usdt_name,
					   __u64 usdt_cookie);

static inline bool is_pow_of_2(size_t x)
{
	return x && (x & (x - 1)) == 0;
}

#define PROG_LOAD_ATTEMPTS 5
int sys_bpf_prog_load(union bpf_attr *attr, unsigned int size, int attempts);

bool glob_match(const char *str, const char *pat);

long elf_find_func_offset(Elf *elf, const char *binary_path, const char *name);
long elf_find_func_offset_from_file(const char *binary_path, const char *name);

struct elf_fd {
	Elf *elf;
	int fd;
};

int elf_open(const char *binary_path, struct elf_fd *elf_fd);
void elf_close(struct elf_fd *elf_fd);

int elf_resolve_syms_offsets(const char *binary_path, int cnt,
			     const char **syms, unsigned long **poffsets,
			     int st_type);
int elf_resolve_pattern_offsets(const char *binary_path, const char *pattern,
				 unsigned long **poffsets, size_t *pcnt);

int probe_fd(int fd);

#endif /* __LIBBPF_LIBBPF_INTERNAL_H */