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[mirror_ubuntu-artful-kernel.git] / tools / lib / bpf / libbpf.c
1 /*
2 * Common eBPF ELF object loading operations.
3 *
4 * Copyright (C) 2013-2015 Alexei Starovoitov <ast@kernel.org>
5 * Copyright (C) 2015 Wang Nan <wangnan0@huawei.com>
6 * Copyright (C) 2015 Huawei Inc.
7 * Copyright (C) 2017 Nicira, Inc.
8 *
9 * This program is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU Lesser General Public
11 * License as published by the Free Software Foundation;
12 * version 2.1 of the License (not later!)
13 *
14 * This program is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 * GNU Lesser General Public License for more details.
18 *
19 * You should have received a copy of the GNU Lesser General Public
20 * License along with this program; if not, see <http://www.gnu.org/licenses>
21 */
22
23 #include <stdlib.h>
24 #include <stdio.h>
25 #include <stdarg.h>
26 #include <libgen.h>
27 #include <inttypes.h>
28 #include <string.h>
29 #include <unistd.h>
30 #include <fcntl.h>
31 #include <errno.h>
32 #include <asm/unistd.h>
33 #include <linux/err.h>
34 #include <linux/kernel.h>
35 #include <linux/bpf.h>
36 #include <linux/list.h>
37 #include <linux/limits.h>
38 #include <sys/stat.h>
39 #include <sys/types.h>
40 #include <sys/vfs.h>
41 #include <libelf.h>
42 #include <gelf.h>
43
44 #include "libbpf.h"
45 #include "bpf.h"
46
47 #ifndef EM_BPF
48 #define EM_BPF 247
49 #endif
50
51 #ifndef BPF_FS_MAGIC
52 #define BPF_FS_MAGIC 0xcafe4a11
53 #endif
54
55 #define __printf(a, b) __attribute__((format(printf, a, b)))
56
57 __printf(1, 2)
58 static int __base_pr(const char *format, ...)
59 {
60 va_list args;
61 int err;
62
63 va_start(args, format);
64 err = vfprintf(stderr, format, args);
65 va_end(args);
66 return err;
67 }
68
69 static __printf(1, 2) libbpf_print_fn_t __pr_warning = __base_pr;
70 static __printf(1, 2) libbpf_print_fn_t __pr_info = __base_pr;
71 static __printf(1, 2) libbpf_print_fn_t __pr_debug;
72
73 #define __pr(func, fmt, ...) \
74 do { \
75 if ((func)) \
76 (func)("libbpf: " fmt, ##__VA_ARGS__); \
77 } while (0)
78
79 #define pr_warning(fmt, ...) __pr(__pr_warning, fmt, ##__VA_ARGS__)
80 #define pr_info(fmt, ...) __pr(__pr_info, fmt, ##__VA_ARGS__)
81 #define pr_debug(fmt, ...) __pr(__pr_debug, fmt, ##__VA_ARGS__)
82
83 void libbpf_set_print(libbpf_print_fn_t warn,
84 libbpf_print_fn_t info,
85 libbpf_print_fn_t debug)
86 {
87 __pr_warning = warn;
88 __pr_info = info;
89 __pr_debug = debug;
90 }
91
92 #define STRERR_BUFSIZE 128
93
94 #define ERRNO_OFFSET(e) ((e) - __LIBBPF_ERRNO__START)
95 #define ERRCODE_OFFSET(c) ERRNO_OFFSET(LIBBPF_ERRNO__##c)
96 #define NR_ERRNO (__LIBBPF_ERRNO__END - __LIBBPF_ERRNO__START)
97
98 static const char *libbpf_strerror_table[NR_ERRNO] = {
99 [ERRCODE_OFFSET(LIBELF)] = "Something wrong in libelf",
100 [ERRCODE_OFFSET(FORMAT)] = "BPF object format invalid",
101 [ERRCODE_OFFSET(KVERSION)] = "'version' section incorrect or lost",
102 [ERRCODE_OFFSET(ENDIAN)] = "Endian mismatch",
103 [ERRCODE_OFFSET(INTERNAL)] = "Internal error in libbpf",
104 [ERRCODE_OFFSET(RELOC)] = "Relocation failed",
105 [ERRCODE_OFFSET(VERIFY)] = "Kernel verifier blocks program loading",
106 [ERRCODE_OFFSET(PROG2BIG)] = "Program too big",
107 [ERRCODE_OFFSET(KVER)] = "Incorrect kernel version",
108 [ERRCODE_OFFSET(PROGTYPE)] = "Kernel doesn't support this program type",
109 };
110
111 int libbpf_strerror(int err, char *buf, size_t size)
112 {
113 if (!buf || !size)
114 return -1;
115
116 err = err > 0 ? err : -err;
117
118 if (err < __LIBBPF_ERRNO__START) {
119 int ret;
120
121 ret = strerror_r(err, buf, size);
122 buf[size - 1] = '\0';
123 return ret;
124 }
125
126 if (err < __LIBBPF_ERRNO__END) {
127 const char *msg;
128
129 msg = libbpf_strerror_table[ERRNO_OFFSET(err)];
130 snprintf(buf, size, "%s", msg);
131 buf[size - 1] = '\0';
132 return 0;
133 }
134
135 snprintf(buf, size, "Unknown libbpf error %d", err);
136 buf[size - 1] = '\0';
137 return -1;
138 }
139
140 #define CHECK_ERR(action, err, out) do { \
141 err = action; \
142 if (err) \
143 goto out; \
144 } while(0)
145
146
147 /* Copied from tools/perf/util/util.h */
148 #ifndef zfree
149 # define zfree(ptr) ({ free(*ptr); *ptr = NULL; })
150 #endif
151
152 #ifndef zclose
153 # define zclose(fd) ({ \
154 int ___err = 0; \
155 if ((fd) >= 0) \
156 ___err = close((fd)); \
157 fd = -1; \
158 ___err; })
159 #endif
160
161 #ifdef HAVE_LIBELF_MMAP_SUPPORT
162 # define LIBBPF_ELF_C_READ_MMAP ELF_C_READ_MMAP
163 #else
164 # define LIBBPF_ELF_C_READ_MMAP ELF_C_READ
165 #endif
166
167 /*
168 * bpf_prog should be a better name but it has been used in
169 * linux/filter.h.
170 */
171 struct bpf_program {
172 /* Index in elf obj file, for relocation use. */
173 int idx;
174 char *section_name;
175 struct bpf_insn *insns;
176 size_t insns_cnt;
177 enum bpf_prog_type type;
178
179 struct {
180 int insn_idx;
181 int map_idx;
182 } *reloc_desc;
183 int nr_reloc;
184
185 struct {
186 int nr;
187 int *fds;
188 } instances;
189 bpf_program_prep_t preprocessor;
190
191 struct bpf_object *obj;
192 void *priv;
193 bpf_program_clear_priv_t clear_priv;
194 };
195
196 struct bpf_map {
197 int fd;
198 char *name;
199 size_t offset;
200 struct bpf_map_def def;
201 void *priv;
202 bpf_map_clear_priv_t clear_priv;
203 };
204
205 static LIST_HEAD(bpf_objects_list);
206
207 struct bpf_object {
208 char license[64];
209 u32 kern_version;
210
211 struct bpf_program *programs;
212 size_t nr_programs;
213 struct bpf_map *maps;
214 size_t nr_maps;
215
216 bool loaded;
217
218 /*
219 * Information when doing elf related work. Only valid if fd
220 * is valid.
221 */
222 struct {
223 int fd;
224 void *obj_buf;
225 size_t obj_buf_sz;
226 Elf *elf;
227 GElf_Ehdr ehdr;
228 Elf_Data *symbols;
229 size_t strtabidx;
230 struct {
231 GElf_Shdr shdr;
232 Elf_Data *data;
233 } *reloc;
234 int nr_reloc;
235 int maps_shndx;
236 } efile;
237 /*
238 * All loaded bpf_object is linked in a list, which is
239 * hidden to caller. bpf_objects__<func> handlers deal with
240 * all objects.
241 */
242 struct list_head list;
243
244 void *priv;
245 bpf_object_clear_priv_t clear_priv;
246
247 char path[];
248 };
249 #define obj_elf_valid(o) ((o)->efile.elf)
250
251 static void bpf_program__unload(struct bpf_program *prog)
252 {
253 int i;
254
255 if (!prog)
256 return;
257
258 /*
259 * If the object is opened but the program was never loaded,
260 * it is possible that prog->instances.nr == -1.
261 */
262 if (prog->instances.nr > 0) {
263 for (i = 0; i < prog->instances.nr; i++)
264 zclose(prog->instances.fds[i]);
265 } else if (prog->instances.nr != -1) {
266 pr_warning("Internal error: instances.nr is %d\n",
267 prog->instances.nr);
268 }
269
270 prog->instances.nr = -1;
271 zfree(&prog->instances.fds);
272 }
273
274 static void bpf_program__exit(struct bpf_program *prog)
275 {
276 if (!prog)
277 return;
278
279 if (prog->clear_priv)
280 prog->clear_priv(prog, prog->priv);
281
282 prog->priv = NULL;
283 prog->clear_priv = NULL;
284
285 bpf_program__unload(prog);
286 zfree(&prog->section_name);
287 zfree(&prog->insns);
288 zfree(&prog->reloc_desc);
289
290 prog->nr_reloc = 0;
291 prog->insns_cnt = 0;
292 prog->idx = -1;
293 }
294
295 static int
296 bpf_program__init(void *data, size_t size, char *name, int idx,
297 struct bpf_program *prog)
298 {
299 if (size < sizeof(struct bpf_insn)) {
300 pr_warning("corrupted section '%s'\n", name);
301 return -EINVAL;
302 }
303
304 bzero(prog, sizeof(*prog));
305
306 prog->section_name = strdup(name);
307 if (!prog->section_name) {
308 pr_warning("failed to alloc name for prog %s\n",
309 name);
310 goto errout;
311 }
312
313 prog->insns = malloc(size);
314 if (!prog->insns) {
315 pr_warning("failed to alloc insns for %s\n", name);
316 goto errout;
317 }
318 prog->insns_cnt = size / sizeof(struct bpf_insn);
319 memcpy(prog->insns, data,
320 prog->insns_cnt * sizeof(struct bpf_insn));
321 prog->idx = idx;
322 prog->instances.fds = NULL;
323 prog->instances.nr = -1;
324 prog->type = BPF_PROG_TYPE_KPROBE;
325
326 return 0;
327 errout:
328 bpf_program__exit(prog);
329 return -ENOMEM;
330 }
331
332 static int
333 bpf_object__add_program(struct bpf_object *obj, void *data, size_t size,
334 char *name, int idx)
335 {
336 struct bpf_program prog, *progs;
337 int nr_progs, err;
338
339 err = bpf_program__init(data, size, name, idx, &prog);
340 if (err)
341 return err;
342
343 progs = obj->programs;
344 nr_progs = obj->nr_programs;
345
346 progs = realloc(progs, sizeof(progs[0]) * (nr_progs + 1));
347 if (!progs) {
348 /*
349 * In this case the original obj->programs
350 * is still valid, so don't need special treat for
351 * bpf_close_object().
352 */
353 pr_warning("failed to alloc a new program '%s'\n",
354 name);
355 bpf_program__exit(&prog);
356 return -ENOMEM;
357 }
358
359 pr_debug("found program %s\n", prog.section_name);
360 obj->programs = progs;
361 obj->nr_programs = nr_progs + 1;
362 prog.obj = obj;
363 progs[nr_progs] = prog;
364 return 0;
365 }
366
367 static struct bpf_object *bpf_object__new(const char *path,
368 void *obj_buf,
369 size_t obj_buf_sz)
370 {
371 struct bpf_object *obj;
372
373 obj = calloc(1, sizeof(struct bpf_object) + strlen(path) + 1);
374 if (!obj) {
375 pr_warning("alloc memory failed for %s\n", path);
376 return ERR_PTR(-ENOMEM);
377 }
378
379 strcpy(obj->path, path);
380 obj->efile.fd = -1;
381
382 /*
383 * Caller of this function should also calls
384 * bpf_object__elf_finish() after data collection to return
385 * obj_buf to user. If not, we should duplicate the buffer to
386 * avoid user freeing them before elf finish.
387 */
388 obj->efile.obj_buf = obj_buf;
389 obj->efile.obj_buf_sz = obj_buf_sz;
390 obj->efile.maps_shndx = -1;
391
392 obj->loaded = false;
393
394 INIT_LIST_HEAD(&obj->list);
395 list_add(&obj->list, &bpf_objects_list);
396 return obj;
397 }
398
399 static void bpf_object__elf_finish(struct bpf_object *obj)
400 {
401 if (!obj_elf_valid(obj))
402 return;
403
404 if (obj->efile.elf) {
405 elf_end(obj->efile.elf);
406 obj->efile.elf = NULL;
407 }
408 obj->efile.symbols = NULL;
409
410 zfree(&obj->efile.reloc);
411 obj->efile.nr_reloc = 0;
412 zclose(obj->efile.fd);
413 obj->efile.obj_buf = NULL;
414 obj->efile.obj_buf_sz = 0;
415 }
416
417 static int bpf_object__elf_init(struct bpf_object *obj)
418 {
419 int err = 0;
420 GElf_Ehdr *ep;
421
422 if (obj_elf_valid(obj)) {
423 pr_warning("elf init: internal error\n");
424 return -LIBBPF_ERRNO__LIBELF;
425 }
426
427 if (obj->efile.obj_buf_sz > 0) {
428 /*
429 * obj_buf should have been validated by
430 * bpf_object__open_buffer().
431 */
432 obj->efile.elf = elf_memory(obj->efile.obj_buf,
433 obj->efile.obj_buf_sz);
434 } else {
435 obj->efile.fd = open(obj->path, O_RDONLY);
436 if (obj->efile.fd < 0) {
437 pr_warning("failed to open %s: %s\n", obj->path,
438 strerror(errno));
439 return -errno;
440 }
441
442 obj->efile.elf = elf_begin(obj->efile.fd,
443 LIBBPF_ELF_C_READ_MMAP,
444 NULL);
445 }
446
447 if (!obj->efile.elf) {
448 pr_warning("failed to open %s as ELF file\n",
449 obj->path);
450 err = -LIBBPF_ERRNO__LIBELF;
451 goto errout;
452 }
453
454 if (!gelf_getehdr(obj->efile.elf, &obj->efile.ehdr)) {
455 pr_warning("failed to get EHDR from %s\n",
456 obj->path);
457 err = -LIBBPF_ERRNO__FORMAT;
458 goto errout;
459 }
460 ep = &obj->efile.ehdr;
461
462 /* Old LLVM set e_machine to EM_NONE */
463 if ((ep->e_type != ET_REL) || (ep->e_machine && (ep->e_machine != EM_BPF))) {
464 pr_warning("%s is not an eBPF object file\n",
465 obj->path);
466 err = -LIBBPF_ERRNO__FORMAT;
467 goto errout;
468 }
469
470 return 0;
471 errout:
472 bpf_object__elf_finish(obj);
473 return err;
474 }
475
476 static int
477 bpf_object__check_endianness(struct bpf_object *obj)
478 {
479 static unsigned int const endian = 1;
480
481 switch (obj->efile.ehdr.e_ident[EI_DATA]) {
482 case ELFDATA2LSB:
483 /* We are big endian, BPF obj is little endian. */
484 if (*(unsigned char const *)&endian != 1)
485 goto mismatch;
486 break;
487
488 case ELFDATA2MSB:
489 /* We are little endian, BPF obj is big endian. */
490 if (*(unsigned char const *)&endian != 0)
491 goto mismatch;
492 break;
493 default:
494 return -LIBBPF_ERRNO__ENDIAN;
495 }
496
497 return 0;
498
499 mismatch:
500 pr_warning("Error: endianness mismatch.\n");
501 return -LIBBPF_ERRNO__ENDIAN;
502 }
503
504 static int
505 bpf_object__init_license(struct bpf_object *obj,
506 void *data, size_t size)
507 {
508 memcpy(obj->license, data,
509 min(size, sizeof(obj->license) - 1));
510 pr_debug("license of %s is %s\n", obj->path, obj->license);
511 return 0;
512 }
513
514 static int
515 bpf_object__init_kversion(struct bpf_object *obj,
516 void *data, size_t size)
517 {
518 u32 kver;
519
520 if (size != sizeof(kver)) {
521 pr_warning("invalid kver section in %s\n", obj->path);
522 return -LIBBPF_ERRNO__FORMAT;
523 }
524 memcpy(&kver, data, sizeof(kver));
525 obj->kern_version = kver;
526 pr_debug("kernel version of %s is %x\n", obj->path,
527 obj->kern_version);
528 return 0;
529 }
530
531 static int
532 bpf_object__validate_maps(struct bpf_object *obj)
533 {
534 int i;
535
536 /*
537 * If there's only 1 map, the only error case should have been
538 * catched in bpf_object__init_maps().
539 */
540 if (!obj->maps || !obj->nr_maps || (obj->nr_maps == 1))
541 return 0;
542
543 for (i = 1; i < obj->nr_maps; i++) {
544 const struct bpf_map *a = &obj->maps[i - 1];
545 const struct bpf_map *b = &obj->maps[i];
546
547 if (b->offset - a->offset < sizeof(struct bpf_map_def)) {
548 pr_warning("corrupted map section in %s: map \"%s\" too small\n",
549 obj->path, a->name);
550 return -EINVAL;
551 }
552 }
553 return 0;
554 }
555
556 static int compare_bpf_map(const void *_a, const void *_b)
557 {
558 const struct bpf_map *a = _a;
559 const struct bpf_map *b = _b;
560
561 return a->offset - b->offset;
562 }
563
564 static int
565 bpf_object__init_maps(struct bpf_object *obj)
566 {
567 int i, map_idx, nr_maps = 0;
568 Elf_Scn *scn;
569 Elf_Data *data;
570 Elf_Data *symbols = obj->efile.symbols;
571
572 if (obj->efile.maps_shndx < 0)
573 return -EINVAL;
574 if (!symbols)
575 return -EINVAL;
576
577 scn = elf_getscn(obj->efile.elf, obj->efile.maps_shndx);
578 if (scn)
579 data = elf_getdata(scn, NULL);
580 if (!scn || !data) {
581 pr_warning("failed to get Elf_Data from map section %d\n",
582 obj->efile.maps_shndx);
583 return -EINVAL;
584 }
585
586 /*
587 * Count number of maps. Each map has a name.
588 * Array of maps is not supported: only the first element is
589 * considered.
590 *
591 * TODO: Detect array of map and report error.
592 */
593 for (i = 0; i < symbols->d_size / sizeof(GElf_Sym); i++) {
594 GElf_Sym sym;
595
596 if (!gelf_getsym(symbols, i, &sym))
597 continue;
598 if (sym.st_shndx != obj->efile.maps_shndx)
599 continue;
600 nr_maps++;
601 }
602
603 /* Alloc obj->maps and fill nr_maps. */
604 pr_debug("maps in %s: %d maps in %zd bytes\n", obj->path,
605 nr_maps, data->d_size);
606
607 if (!nr_maps)
608 return 0;
609
610 obj->maps = calloc(nr_maps, sizeof(obj->maps[0]));
611 if (!obj->maps) {
612 pr_warning("alloc maps for object failed\n");
613 return -ENOMEM;
614 }
615 obj->nr_maps = nr_maps;
616
617 /*
618 * fill all fd with -1 so won't close incorrect
619 * fd (fd=0 is stdin) when failure (zclose won't close
620 * negative fd)).
621 */
622 for (i = 0; i < nr_maps; i++)
623 obj->maps[i].fd = -1;
624
625 /*
626 * Fill obj->maps using data in "maps" section.
627 */
628 for (i = 0, map_idx = 0; i < symbols->d_size / sizeof(GElf_Sym); i++) {
629 GElf_Sym sym;
630 const char *map_name;
631 struct bpf_map_def *def;
632
633 if (!gelf_getsym(symbols, i, &sym))
634 continue;
635 if (sym.st_shndx != obj->efile.maps_shndx)
636 continue;
637
638 map_name = elf_strptr(obj->efile.elf,
639 obj->efile.strtabidx,
640 sym.st_name);
641 obj->maps[map_idx].offset = sym.st_value;
642 if (sym.st_value + sizeof(struct bpf_map_def) > data->d_size) {
643 pr_warning("corrupted maps section in %s: last map \"%s\" too small\n",
644 obj->path, map_name);
645 return -EINVAL;
646 }
647
648 obj->maps[map_idx].name = strdup(map_name);
649 if (!obj->maps[map_idx].name) {
650 pr_warning("failed to alloc map name\n");
651 return -ENOMEM;
652 }
653 pr_debug("map %d is \"%s\"\n", map_idx,
654 obj->maps[map_idx].name);
655 def = (struct bpf_map_def *)(data->d_buf + sym.st_value);
656 obj->maps[map_idx].def = *def;
657 map_idx++;
658 }
659
660 qsort(obj->maps, obj->nr_maps, sizeof(obj->maps[0]), compare_bpf_map);
661 return bpf_object__validate_maps(obj);
662 }
663
664 static int bpf_object__elf_collect(struct bpf_object *obj)
665 {
666 Elf *elf = obj->efile.elf;
667 GElf_Ehdr *ep = &obj->efile.ehdr;
668 Elf_Scn *scn = NULL;
669 int idx = 0, err = 0;
670
671 /* Elf is corrupted/truncated, avoid calling elf_strptr. */
672 if (!elf_rawdata(elf_getscn(elf, ep->e_shstrndx), NULL)) {
673 pr_warning("failed to get e_shstrndx from %s\n",
674 obj->path);
675 return -LIBBPF_ERRNO__FORMAT;
676 }
677
678 while ((scn = elf_nextscn(elf, scn)) != NULL) {
679 char *name;
680 GElf_Shdr sh;
681 Elf_Data *data;
682
683 idx++;
684 if (gelf_getshdr(scn, &sh) != &sh) {
685 pr_warning("failed to get section header from %s\n",
686 obj->path);
687 err = -LIBBPF_ERRNO__FORMAT;
688 goto out;
689 }
690
691 name = elf_strptr(elf, ep->e_shstrndx, sh.sh_name);
692 if (!name) {
693 pr_warning("failed to get section name from %s\n",
694 obj->path);
695 err = -LIBBPF_ERRNO__FORMAT;
696 goto out;
697 }
698
699 data = elf_getdata(scn, 0);
700 if (!data) {
701 pr_warning("failed to get section data from %s(%s)\n",
702 name, obj->path);
703 err = -LIBBPF_ERRNO__FORMAT;
704 goto out;
705 }
706 pr_debug("section %s, size %ld, link %d, flags %lx, type=%d\n",
707 name, (unsigned long)data->d_size,
708 (int)sh.sh_link, (unsigned long)sh.sh_flags,
709 (int)sh.sh_type);
710
711 if (strcmp(name, "license") == 0)
712 err = bpf_object__init_license(obj,
713 data->d_buf,
714 data->d_size);
715 else if (strcmp(name, "version") == 0)
716 err = bpf_object__init_kversion(obj,
717 data->d_buf,
718 data->d_size);
719 else if (strcmp(name, "maps") == 0)
720 obj->efile.maps_shndx = idx;
721 else if (sh.sh_type == SHT_SYMTAB) {
722 if (obj->efile.symbols) {
723 pr_warning("bpf: multiple SYMTAB in %s\n",
724 obj->path);
725 err = -LIBBPF_ERRNO__FORMAT;
726 } else {
727 obj->efile.symbols = data;
728 obj->efile.strtabidx = sh.sh_link;
729 }
730 } else if ((sh.sh_type == SHT_PROGBITS) &&
731 (sh.sh_flags & SHF_EXECINSTR) &&
732 (data->d_size > 0)) {
733 err = bpf_object__add_program(obj, data->d_buf,
734 data->d_size, name, idx);
735 if (err) {
736 char errmsg[STRERR_BUFSIZE];
737
738 strerror_r(-err, errmsg, sizeof(errmsg));
739 pr_warning("failed to alloc program %s (%s): %s",
740 name, obj->path, errmsg);
741 }
742 } else if (sh.sh_type == SHT_REL) {
743 void *reloc = obj->efile.reloc;
744 int nr_reloc = obj->efile.nr_reloc + 1;
745
746 reloc = realloc(reloc,
747 sizeof(*obj->efile.reloc) * nr_reloc);
748 if (!reloc) {
749 pr_warning("realloc failed\n");
750 err = -ENOMEM;
751 } else {
752 int n = nr_reloc - 1;
753
754 obj->efile.reloc = reloc;
755 obj->efile.nr_reloc = nr_reloc;
756
757 obj->efile.reloc[n].shdr = sh;
758 obj->efile.reloc[n].data = data;
759 }
760 }
761 if (err)
762 goto out;
763 }
764
765 if (!obj->efile.strtabidx || obj->efile.strtabidx >= idx) {
766 pr_warning("Corrupted ELF file: index of strtab invalid\n");
767 return LIBBPF_ERRNO__FORMAT;
768 }
769 if (obj->efile.maps_shndx >= 0)
770 err = bpf_object__init_maps(obj);
771 out:
772 return err;
773 }
774
775 static struct bpf_program *
776 bpf_object__find_prog_by_idx(struct bpf_object *obj, int idx)
777 {
778 struct bpf_program *prog;
779 size_t i;
780
781 for (i = 0; i < obj->nr_programs; i++) {
782 prog = &obj->programs[i];
783 if (prog->idx == idx)
784 return prog;
785 }
786 return NULL;
787 }
788
789 static int
790 bpf_program__collect_reloc(struct bpf_program *prog,
791 size_t nr_maps, GElf_Shdr *shdr,
792 Elf_Data *data, Elf_Data *symbols,
793 int maps_shndx, struct bpf_map *maps)
794 {
795 int i, nrels;
796
797 pr_debug("collecting relocating info for: '%s'\n",
798 prog->section_name);
799 nrels = shdr->sh_size / shdr->sh_entsize;
800
801 prog->reloc_desc = malloc(sizeof(*prog->reloc_desc) * nrels);
802 if (!prog->reloc_desc) {
803 pr_warning("failed to alloc memory in relocation\n");
804 return -ENOMEM;
805 }
806 prog->nr_reloc = nrels;
807
808 for (i = 0; i < nrels; i++) {
809 GElf_Sym sym;
810 GElf_Rel rel;
811 unsigned int insn_idx;
812 struct bpf_insn *insns = prog->insns;
813 size_t map_idx;
814
815 if (!gelf_getrel(data, i, &rel)) {
816 pr_warning("relocation: failed to get %d reloc\n", i);
817 return -LIBBPF_ERRNO__FORMAT;
818 }
819
820 if (!gelf_getsym(symbols,
821 GELF_R_SYM(rel.r_info),
822 &sym)) {
823 pr_warning("relocation: symbol %"PRIx64" not found\n",
824 GELF_R_SYM(rel.r_info));
825 return -LIBBPF_ERRNO__FORMAT;
826 }
827
828 if (sym.st_shndx != maps_shndx) {
829 pr_warning("Program '%s' contains non-map related relo data pointing to section %u\n",
830 prog->section_name, sym.st_shndx);
831 return -LIBBPF_ERRNO__RELOC;
832 }
833
834 insn_idx = rel.r_offset / sizeof(struct bpf_insn);
835 pr_debug("relocation: insn_idx=%u\n", insn_idx);
836
837 if (insns[insn_idx].code != (BPF_LD | BPF_IMM | BPF_DW)) {
838 pr_warning("bpf: relocation: invalid relo for insns[%d].code 0x%x\n",
839 insn_idx, insns[insn_idx].code);
840 return -LIBBPF_ERRNO__RELOC;
841 }
842
843 /* TODO: 'maps' is sorted. We can use bsearch to make it faster. */
844 for (map_idx = 0; map_idx < nr_maps; map_idx++) {
845 if (maps[map_idx].offset == sym.st_value) {
846 pr_debug("relocation: find map %zd (%s) for insn %u\n",
847 map_idx, maps[map_idx].name, insn_idx);
848 break;
849 }
850 }
851
852 if (map_idx >= nr_maps) {
853 pr_warning("bpf relocation: map_idx %d large than %d\n",
854 (int)map_idx, (int)nr_maps - 1);
855 return -LIBBPF_ERRNO__RELOC;
856 }
857
858 prog->reloc_desc[i].insn_idx = insn_idx;
859 prog->reloc_desc[i].map_idx = map_idx;
860 }
861 return 0;
862 }
863
864 static int
865 bpf_object__create_maps(struct bpf_object *obj)
866 {
867 unsigned int i;
868
869 for (i = 0; i < obj->nr_maps; i++) {
870 struct bpf_map_def *def = &obj->maps[i].def;
871 int *pfd = &obj->maps[i].fd;
872
873 *pfd = bpf_create_map(def->type,
874 def->key_size,
875 def->value_size,
876 def->max_entries,
877 0);
878 if (*pfd < 0) {
879 size_t j;
880 int err = *pfd;
881
882 pr_warning("failed to create map: %s\n",
883 strerror(errno));
884 for (j = 0; j < i; j++)
885 zclose(obj->maps[j].fd);
886 return err;
887 }
888 pr_debug("create map %s: fd=%d\n", obj->maps[i].name, *pfd);
889 }
890
891 return 0;
892 }
893
894 static int
895 bpf_program__relocate(struct bpf_program *prog, struct bpf_object *obj)
896 {
897 int i;
898
899 if (!prog || !prog->reloc_desc)
900 return 0;
901
902 for (i = 0; i < prog->nr_reloc; i++) {
903 int insn_idx, map_idx;
904 struct bpf_insn *insns = prog->insns;
905
906 insn_idx = prog->reloc_desc[i].insn_idx;
907 map_idx = prog->reloc_desc[i].map_idx;
908
909 if (insn_idx >= (int)prog->insns_cnt) {
910 pr_warning("relocation out of range: '%s'\n",
911 prog->section_name);
912 return -LIBBPF_ERRNO__RELOC;
913 }
914 insns[insn_idx].src_reg = BPF_PSEUDO_MAP_FD;
915 insns[insn_idx].imm = obj->maps[map_idx].fd;
916 }
917
918 zfree(&prog->reloc_desc);
919 prog->nr_reloc = 0;
920 return 0;
921 }
922
923
924 static int
925 bpf_object__relocate(struct bpf_object *obj)
926 {
927 struct bpf_program *prog;
928 size_t i;
929 int err;
930
931 for (i = 0; i < obj->nr_programs; i++) {
932 prog = &obj->programs[i];
933
934 err = bpf_program__relocate(prog, obj);
935 if (err) {
936 pr_warning("failed to relocate '%s'\n",
937 prog->section_name);
938 return err;
939 }
940 }
941 return 0;
942 }
943
944 static int bpf_object__collect_reloc(struct bpf_object *obj)
945 {
946 int i, err;
947
948 if (!obj_elf_valid(obj)) {
949 pr_warning("Internal error: elf object is closed\n");
950 return -LIBBPF_ERRNO__INTERNAL;
951 }
952
953 for (i = 0; i < obj->efile.nr_reloc; i++) {
954 GElf_Shdr *shdr = &obj->efile.reloc[i].shdr;
955 Elf_Data *data = obj->efile.reloc[i].data;
956 int idx = shdr->sh_info;
957 struct bpf_program *prog;
958 size_t nr_maps = obj->nr_maps;
959
960 if (shdr->sh_type != SHT_REL) {
961 pr_warning("internal error at %d\n", __LINE__);
962 return -LIBBPF_ERRNO__INTERNAL;
963 }
964
965 prog = bpf_object__find_prog_by_idx(obj, idx);
966 if (!prog) {
967 pr_warning("relocation failed: no %d section\n",
968 idx);
969 return -LIBBPF_ERRNO__RELOC;
970 }
971
972 err = bpf_program__collect_reloc(prog, nr_maps,
973 shdr, data,
974 obj->efile.symbols,
975 obj->efile.maps_shndx,
976 obj->maps);
977 if (err)
978 return err;
979 }
980 return 0;
981 }
982
983 static int
984 load_program(enum bpf_prog_type type, struct bpf_insn *insns,
985 int insns_cnt, char *license, u32 kern_version, int *pfd)
986 {
987 int ret;
988 char *log_buf;
989
990 if (!insns || !insns_cnt)
991 return -EINVAL;
992
993 log_buf = malloc(BPF_LOG_BUF_SIZE);
994 if (!log_buf)
995 pr_warning("Alloc log buffer for bpf loader error, continue without log\n");
996
997 ret = bpf_load_program(type, insns, insns_cnt, license,
998 kern_version, log_buf, BPF_LOG_BUF_SIZE);
999
1000 if (ret >= 0) {
1001 *pfd = ret;
1002 ret = 0;
1003 goto out;
1004 }
1005
1006 ret = -LIBBPF_ERRNO__LOAD;
1007 pr_warning("load bpf program failed: %s\n", strerror(errno));
1008
1009 if (log_buf && log_buf[0] != '\0') {
1010 ret = -LIBBPF_ERRNO__VERIFY;
1011 pr_warning("-- BEGIN DUMP LOG ---\n");
1012 pr_warning("\n%s\n", log_buf);
1013 pr_warning("-- END LOG --\n");
1014 } else if (insns_cnt >= BPF_MAXINSNS) {
1015 pr_warning("Program too large (%d insns), at most %d insns\n",
1016 insns_cnt, BPF_MAXINSNS);
1017 ret = -LIBBPF_ERRNO__PROG2BIG;
1018 } else {
1019 /* Wrong program type? */
1020 if (type != BPF_PROG_TYPE_KPROBE) {
1021 int fd;
1022
1023 fd = bpf_load_program(BPF_PROG_TYPE_KPROBE, insns,
1024 insns_cnt, license, kern_version,
1025 NULL, 0);
1026 if (fd >= 0) {
1027 close(fd);
1028 ret = -LIBBPF_ERRNO__PROGTYPE;
1029 goto out;
1030 }
1031 }
1032
1033 if (log_buf)
1034 ret = -LIBBPF_ERRNO__KVER;
1035 }
1036
1037 out:
1038 free(log_buf);
1039 return ret;
1040 }
1041
1042 static int
1043 bpf_program__load(struct bpf_program *prog,
1044 char *license, u32 kern_version)
1045 {
1046 int err = 0, fd, i;
1047
1048 if (prog->instances.nr < 0 || !prog->instances.fds) {
1049 if (prog->preprocessor) {
1050 pr_warning("Internal error: can't load program '%s'\n",
1051 prog->section_name);
1052 return -LIBBPF_ERRNO__INTERNAL;
1053 }
1054
1055 prog->instances.fds = malloc(sizeof(int));
1056 if (!prog->instances.fds) {
1057 pr_warning("Not enough memory for BPF fds\n");
1058 return -ENOMEM;
1059 }
1060 prog->instances.nr = 1;
1061 prog->instances.fds[0] = -1;
1062 }
1063
1064 if (!prog->preprocessor) {
1065 if (prog->instances.nr != 1) {
1066 pr_warning("Program '%s' is inconsistent: nr(%d) != 1\n",
1067 prog->section_name, prog->instances.nr);
1068 }
1069 err = load_program(prog->type, prog->insns, prog->insns_cnt,
1070 license, kern_version, &fd);
1071 if (!err)
1072 prog->instances.fds[0] = fd;
1073 goto out;
1074 }
1075
1076 for (i = 0; i < prog->instances.nr; i++) {
1077 struct bpf_prog_prep_result result;
1078 bpf_program_prep_t preprocessor = prog->preprocessor;
1079
1080 bzero(&result, sizeof(result));
1081 err = preprocessor(prog, i, prog->insns,
1082 prog->insns_cnt, &result);
1083 if (err) {
1084 pr_warning("Preprocessing the %dth instance of program '%s' failed\n",
1085 i, prog->section_name);
1086 goto out;
1087 }
1088
1089 if (!result.new_insn_ptr || !result.new_insn_cnt) {
1090 pr_debug("Skip loading the %dth instance of program '%s'\n",
1091 i, prog->section_name);
1092 prog->instances.fds[i] = -1;
1093 if (result.pfd)
1094 *result.pfd = -1;
1095 continue;
1096 }
1097
1098 err = load_program(prog->type, result.new_insn_ptr,
1099 result.new_insn_cnt,
1100 license, kern_version, &fd);
1101
1102 if (err) {
1103 pr_warning("Loading the %dth instance of program '%s' failed\n",
1104 i, prog->section_name);
1105 goto out;
1106 }
1107
1108 if (result.pfd)
1109 *result.pfd = fd;
1110 prog->instances.fds[i] = fd;
1111 }
1112 out:
1113 if (err)
1114 pr_warning("failed to load program '%s'\n",
1115 prog->section_name);
1116 zfree(&prog->insns);
1117 prog->insns_cnt = 0;
1118 return err;
1119 }
1120
1121 static int
1122 bpf_object__load_progs(struct bpf_object *obj)
1123 {
1124 size_t i;
1125 int err;
1126
1127 for (i = 0; i < obj->nr_programs; i++) {
1128 err = bpf_program__load(&obj->programs[i],
1129 obj->license,
1130 obj->kern_version);
1131 if (err)
1132 return err;
1133 }
1134 return 0;
1135 }
1136
1137 static int bpf_object__validate(struct bpf_object *obj)
1138 {
1139 if (obj->kern_version == 0) {
1140 pr_warning("%s doesn't provide kernel version\n",
1141 obj->path);
1142 return -LIBBPF_ERRNO__KVERSION;
1143 }
1144 return 0;
1145 }
1146
1147 static struct bpf_object *
1148 __bpf_object__open(const char *path, void *obj_buf, size_t obj_buf_sz)
1149 {
1150 struct bpf_object *obj;
1151 int err;
1152
1153 if (elf_version(EV_CURRENT) == EV_NONE) {
1154 pr_warning("failed to init libelf for %s\n", path);
1155 return ERR_PTR(-LIBBPF_ERRNO__LIBELF);
1156 }
1157
1158 obj = bpf_object__new(path, obj_buf, obj_buf_sz);
1159 if (IS_ERR(obj))
1160 return obj;
1161
1162 CHECK_ERR(bpf_object__elf_init(obj), err, out);
1163 CHECK_ERR(bpf_object__check_endianness(obj), err, out);
1164 CHECK_ERR(bpf_object__elf_collect(obj), err, out);
1165 CHECK_ERR(bpf_object__collect_reloc(obj), err, out);
1166 CHECK_ERR(bpf_object__validate(obj), err, out);
1167
1168 bpf_object__elf_finish(obj);
1169 return obj;
1170 out:
1171 bpf_object__close(obj);
1172 return ERR_PTR(err);
1173 }
1174
1175 struct bpf_object *bpf_object__open(const char *path)
1176 {
1177 /* param validation */
1178 if (!path)
1179 return NULL;
1180
1181 pr_debug("loading %s\n", path);
1182
1183 return __bpf_object__open(path, NULL, 0);
1184 }
1185
1186 struct bpf_object *bpf_object__open_buffer(void *obj_buf,
1187 size_t obj_buf_sz,
1188 const char *name)
1189 {
1190 char tmp_name[64];
1191
1192 /* param validation */
1193 if (!obj_buf || obj_buf_sz <= 0)
1194 return NULL;
1195
1196 if (!name) {
1197 snprintf(tmp_name, sizeof(tmp_name), "%lx-%lx",
1198 (unsigned long)obj_buf,
1199 (unsigned long)obj_buf_sz);
1200 tmp_name[sizeof(tmp_name) - 1] = '\0';
1201 name = tmp_name;
1202 }
1203 pr_debug("loading object '%s' from buffer\n",
1204 name);
1205
1206 return __bpf_object__open(name, obj_buf, obj_buf_sz);
1207 }
1208
1209 int bpf_object__unload(struct bpf_object *obj)
1210 {
1211 size_t i;
1212
1213 if (!obj)
1214 return -EINVAL;
1215
1216 for (i = 0; i < obj->nr_maps; i++)
1217 zclose(obj->maps[i].fd);
1218
1219 for (i = 0; i < obj->nr_programs; i++)
1220 bpf_program__unload(&obj->programs[i]);
1221
1222 return 0;
1223 }
1224
1225 int bpf_object__load(struct bpf_object *obj)
1226 {
1227 int err;
1228
1229 if (!obj)
1230 return -EINVAL;
1231
1232 if (obj->loaded) {
1233 pr_warning("object should not be loaded twice\n");
1234 return -EINVAL;
1235 }
1236
1237 obj->loaded = true;
1238
1239 CHECK_ERR(bpf_object__create_maps(obj), err, out);
1240 CHECK_ERR(bpf_object__relocate(obj), err, out);
1241 CHECK_ERR(bpf_object__load_progs(obj), err, out);
1242
1243 return 0;
1244 out:
1245 bpf_object__unload(obj);
1246 pr_warning("failed to load object '%s'\n", obj->path);
1247 return err;
1248 }
1249
1250 static int check_path(const char *path)
1251 {
1252 struct statfs st_fs;
1253 char *dname, *dir;
1254 int err = 0;
1255
1256 if (path == NULL)
1257 return -EINVAL;
1258
1259 dname = strdup(path);
1260 if (dname == NULL)
1261 return -ENOMEM;
1262
1263 dir = dirname(dname);
1264 if (statfs(dir, &st_fs)) {
1265 pr_warning("failed to statfs %s: %s\n", dir, strerror(errno));
1266 err = -errno;
1267 }
1268 free(dname);
1269
1270 if (!err && st_fs.f_type != BPF_FS_MAGIC) {
1271 pr_warning("specified path %s is not on BPF FS\n", path);
1272 err = -EINVAL;
1273 }
1274
1275 return err;
1276 }
1277
1278 int bpf_program__pin_instance(struct bpf_program *prog, const char *path,
1279 int instance)
1280 {
1281 int err;
1282
1283 err = check_path(path);
1284 if (err)
1285 return err;
1286
1287 if (prog == NULL) {
1288 pr_warning("invalid program pointer\n");
1289 return -EINVAL;
1290 }
1291
1292 if (instance < 0 || instance >= prog->instances.nr) {
1293 pr_warning("invalid prog instance %d of prog %s (max %d)\n",
1294 instance, prog->section_name, prog->instances.nr);
1295 return -EINVAL;
1296 }
1297
1298 if (bpf_obj_pin(prog->instances.fds[instance], path)) {
1299 pr_warning("failed to pin program: %s\n", strerror(errno));
1300 return -errno;
1301 }
1302 pr_debug("pinned program '%s'\n", path);
1303
1304 return 0;
1305 }
1306
1307 static int make_dir(const char *path)
1308 {
1309 int err = 0;
1310
1311 if (mkdir(path, 0700) && errno != EEXIST)
1312 err = -errno;
1313
1314 if (err)
1315 pr_warning("failed to mkdir %s: %s\n", path, strerror(-err));
1316 return err;
1317 }
1318
1319 int bpf_program__pin(struct bpf_program *prog, const char *path)
1320 {
1321 int i, err;
1322
1323 err = check_path(path);
1324 if (err)
1325 return err;
1326
1327 if (prog == NULL) {
1328 pr_warning("invalid program pointer\n");
1329 return -EINVAL;
1330 }
1331
1332 if (prog->instances.nr <= 0) {
1333 pr_warning("no instances of prog %s to pin\n",
1334 prog->section_name);
1335 return -EINVAL;
1336 }
1337
1338 err = make_dir(path);
1339 if (err)
1340 return err;
1341
1342 for (i = 0; i < prog->instances.nr; i++) {
1343 char buf[PATH_MAX];
1344 int len;
1345
1346 len = snprintf(buf, PATH_MAX, "%s/%d", path, i);
1347 if (len < 0)
1348 return -EINVAL;
1349 else if (len >= PATH_MAX)
1350 return -ENAMETOOLONG;
1351
1352 err = bpf_program__pin_instance(prog, buf, i);
1353 if (err)
1354 return err;
1355 }
1356
1357 return 0;
1358 }
1359
1360 int bpf_map__pin(struct bpf_map *map, const char *path)
1361 {
1362 int err;
1363
1364 err = check_path(path);
1365 if (err)
1366 return err;
1367
1368 if (map == NULL) {
1369 pr_warning("invalid map pointer\n");
1370 return -EINVAL;
1371 }
1372
1373 if (bpf_obj_pin(map->fd, path)) {
1374 pr_warning("failed to pin map: %s\n", strerror(errno));
1375 return -errno;
1376 }
1377
1378 pr_debug("pinned map '%s'\n", path);
1379 return 0;
1380 }
1381
1382 int bpf_object__pin(struct bpf_object *obj, const char *path)
1383 {
1384 struct bpf_program *prog;
1385 struct bpf_map *map;
1386 int err;
1387
1388 if (!obj)
1389 return -ENOENT;
1390
1391 if (!obj->loaded) {
1392 pr_warning("object not yet loaded; load it first\n");
1393 return -ENOENT;
1394 }
1395
1396 err = make_dir(path);
1397 if (err)
1398 return err;
1399
1400 bpf_map__for_each(map, obj) {
1401 char buf[PATH_MAX];
1402 int len;
1403
1404 len = snprintf(buf, PATH_MAX, "%s/%s", path,
1405 bpf_map__name(map));
1406 if (len < 0)
1407 return -EINVAL;
1408 else if (len >= PATH_MAX)
1409 return -ENAMETOOLONG;
1410
1411 err = bpf_map__pin(map, buf);
1412 if (err)
1413 return err;
1414 }
1415
1416 bpf_object__for_each_program(prog, obj) {
1417 char buf[PATH_MAX];
1418 int len;
1419
1420 len = snprintf(buf, PATH_MAX, "%s/%s", path,
1421 prog->section_name);
1422 if (len < 0)
1423 return -EINVAL;
1424 else if (len >= PATH_MAX)
1425 return -ENAMETOOLONG;
1426
1427 err = bpf_program__pin(prog, buf);
1428 if (err)
1429 return err;
1430 }
1431
1432 return 0;
1433 }
1434
1435 void bpf_object__close(struct bpf_object *obj)
1436 {
1437 size_t i;
1438
1439 if (!obj)
1440 return;
1441
1442 if (obj->clear_priv)
1443 obj->clear_priv(obj, obj->priv);
1444
1445 bpf_object__elf_finish(obj);
1446 bpf_object__unload(obj);
1447
1448 for (i = 0; i < obj->nr_maps; i++) {
1449 zfree(&obj->maps[i].name);
1450 if (obj->maps[i].clear_priv)
1451 obj->maps[i].clear_priv(&obj->maps[i],
1452 obj->maps[i].priv);
1453 obj->maps[i].priv = NULL;
1454 obj->maps[i].clear_priv = NULL;
1455 }
1456 zfree(&obj->maps);
1457 obj->nr_maps = 0;
1458
1459 if (obj->programs && obj->nr_programs) {
1460 for (i = 0; i < obj->nr_programs; i++)
1461 bpf_program__exit(&obj->programs[i]);
1462 }
1463 zfree(&obj->programs);
1464
1465 list_del(&obj->list);
1466 free(obj);
1467 }
1468
1469 struct bpf_object *
1470 bpf_object__next(struct bpf_object *prev)
1471 {
1472 struct bpf_object *next;
1473
1474 if (!prev)
1475 next = list_first_entry(&bpf_objects_list,
1476 struct bpf_object,
1477 list);
1478 else
1479 next = list_next_entry(prev, list);
1480
1481 /* Empty list is noticed here so don't need checking on entry. */
1482 if (&next->list == &bpf_objects_list)
1483 return NULL;
1484
1485 return next;
1486 }
1487
1488 const char *bpf_object__name(struct bpf_object *obj)
1489 {
1490 return obj ? obj->path : ERR_PTR(-EINVAL);
1491 }
1492
1493 unsigned int bpf_object__kversion(struct bpf_object *obj)
1494 {
1495 return obj ? obj->kern_version : 0;
1496 }
1497
1498 int bpf_object__set_priv(struct bpf_object *obj, void *priv,
1499 bpf_object_clear_priv_t clear_priv)
1500 {
1501 if (obj->priv && obj->clear_priv)
1502 obj->clear_priv(obj, obj->priv);
1503
1504 obj->priv = priv;
1505 obj->clear_priv = clear_priv;
1506 return 0;
1507 }
1508
1509 void *bpf_object__priv(struct bpf_object *obj)
1510 {
1511 return obj ? obj->priv : ERR_PTR(-EINVAL);
1512 }
1513
1514 struct bpf_program *
1515 bpf_program__next(struct bpf_program *prev, struct bpf_object *obj)
1516 {
1517 size_t idx;
1518
1519 if (!obj->programs)
1520 return NULL;
1521 /* First handler */
1522 if (prev == NULL)
1523 return &obj->programs[0];
1524
1525 if (prev->obj != obj) {
1526 pr_warning("error: program handler doesn't match object\n");
1527 return NULL;
1528 }
1529
1530 idx = (prev - obj->programs) + 1;
1531 if (idx >= obj->nr_programs)
1532 return NULL;
1533 return &obj->programs[idx];
1534 }
1535
1536 int bpf_program__set_priv(struct bpf_program *prog, void *priv,
1537 bpf_program_clear_priv_t clear_priv)
1538 {
1539 if (prog->priv && prog->clear_priv)
1540 prog->clear_priv(prog, prog->priv);
1541
1542 prog->priv = priv;
1543 prog->clear_priv = clear_priv;
1544 return 0;
1545 }
1546
1547 void *bpf_program__priv(struct bpf_program *prog)
1548 {
1549 return prog ? prog->priv : ERR_PTR(-EINVAL);
1550 }
1551
1552 const char *bpf_program__title(struct bpf_program *prog, bool needs_copy)
1553 {
1554 const char *title;
1555
1556 title = prog->section_name;
1557 if (needs_copy) {
1558 title = strdup(title);
1559 if (!title) {
1560 pr_warning("failed to strdup program title\n");
1561 return ERR_PTR(-ENOMEM);
1562 }
1563 }
1564
1565 return title;
1566 }
1567
1568 int bpf_program__fd(struct bpf_program *prog)
1569 {
1570 return bpf_program__nth_fd(prog, 0);
1571 }
1572
1573 int bpf_program__set_prep(struct bpf_program *prog, int nr_instances,
1574 bpf_program_prep_t prep)
1575 {
1576 int *instances_fds;
1577
1578 if (nr_instances <= 0 || !prep)
1579 return -EINVAL;
1580
1581 if (prog->instances.nr > 0 || prog->instances.fds) {
1582 pr_warning("Can't set pre-processor after loading\n");
1583 return -EINVAL;
1584 }
1585
1586 instances_fds = malloc(sizeof(int) * nr_instances);
1587 if (!instances_fds) {
1588 pr_warning("alloc memory failed for fds\n");
1589 return -ENOMEM;
1590 }
1591
1592 /* fill all fd with -1 */
1593 memset(instances_fds, -1, sizeof(int) * nr_instances);
1594
1595 prog->instances.nr = nr_instances;
1596 prog->instances.fds = instances_fds;
1597 prog->preprocessor = prep;
1598 return 0;
1599 }
1600
1601 int bpf_program__nth_fd(struct bpf_program *prog, int n)
1602 {
1603 int fd;
1604
1605 if (n >= prog->instances.nr || n < 0) {
1606 pr_warning("Can't get the %dth fd from program %s: only %d instances\n",
1607 n, prog->section_name, prog->instances.nr);
1608 return -EINVAL;
1609 }
1610
1611 fd = prog->instances.fds[n];
1612 if (fd < 0) {
1613 pr_warning("%dth instance of program '%s' is invalid\n",
1614 n, prog->section_name);
1615 return -ENOENT;
1616 }
1617
1618 return fd;
1619 }
1620
1621 void bpf_program__set_type(struct bpf_program *prog, enum bpf_prog_type type)
1622 {
1623 prog->type = type;
1624 }
1625
1626 static bool bpf_program__is_type(struct bpf_program *prog,
1627 enum bpf_prog_type type)
1628 {
1629 return prog ? (prog->type == type) : false;
1630 }
1631
1632 #define BPF_PROG_TYPE_FNS(NAME, TYPE) \
1633 int bpf_program__set_##NAME(struct bpf_program *prog) \
1634 { \
1635 if (!prog) \
1636 return -EINVAL; \
1637 bpf_program__set_type(prog, TYPE); \
1638 return 0; \
1639 } \
1640 \
1641 bool bpf_program__is_##NAME(struct bpf_program *prog) \
1642 { \
1643 return bpf_program__is_type(prog, TYPE); \
1644 } \
1645
1646 BPF_PROG_TYPE_FNS(socket_filter, BPF_PROG_TYPE_SOCKET_FILTER);
1647 BPF_PROG_TYPE_FNS(kprobe, BPF_PROG_TYPE_KPROBE);
1648 BPF_PROG_TYPE_FNS(sched_cls, BPF_PROG_TYPE_SCHED_CLS);
1649 BPF_PROG_TYPE_FNS(sched_act, BPF_PROG_TYPE_SCHED_ACT);
1650 BPF_PROG_TYPE_FNS(tracepoint, BPF_PROG_TYPE_TRACEPOINT);
1651 BPF_PROG_TYPE_FNS(xdp, BPF_PROG_TYPE_XDP);
1652 BPF_PROG_TYPE_FNS(perf_event, BPF_PROG_TYPE_PERF_EVENT);
1653
1654 int bpf_map__fd(struct bpf_map *map)
1655 {
1656 return map ? map->fd : -EINVAL;
1657 }
1658
1659 const struct bpf_map_def *bpf_map__def(struct bpf_map *map)
1660 {
1661 return map ? &map->def : ERR_PTR(-EINVAL);
1662 }
1663
1664 const char *bpf_map__name(struct bpf_map *map)
1665 {
1666 return map ? map->name : NULL;
1667 }
1668
1669 int bpf_map__set_priv(struct bpf_map *map, void *priv,
1670 bpf_map_clear_priv_t clear_priv)
1671 {
1672 if (!map)
1673 return -EINVAL;
1674
1675 if (map->priv) {
1676 if (map->clear_priv)
1677 map->clear_priv(map, map->priv);
1678 }
1679
1680 map->priv = priv;
1681 map->clear_priv = clear_priv;
1682 return 0;
1683 }
1684
1685 void *bpf_map__priv(struct bpf_map *map)
1686 {
1687 return map ? map->priv : ERR_PTR(-EINVAL);
1688 }
1689
1690 struct bpf_map *
1691 bpf_map__next(struct bpf_map *prev, struct bpf_object *obj)
1692 {
1693 size_t idx;
1694 struct bpf_map *s, *e;
1695
1696 if (!obj || !obj->maps)
1697 return NULL;
1698
1699 s = obj->maps;
1700 e = obj->maps + obj->nr_maps;
1701
1702 if (prev == NULL)
1703 return s;
1704
1705 if ((prev < s) || (prev >= e)) {
1706 pr_warning("error in %s: map handler doesn't belong to object\n",
1707 __func__);
1708 return NULL;
1709 }
1710
1711 idx = (prev - obj->maps) + 1;
1712 if (idx >= obj->nr_maps)
1713 return NULL;
1714 return &obj->maps[idx];
1715 }
1716
1717 struct bpf_map *
1718 bpf_object__find_map_by_name(struct bpf_object *obj, const char *name)
1719 {
1720 struct bpf_map *pos;
1721
1722 bpf_map__for_each(pos, obj) {
1723 if (pos->name && !strcmp(pos->name, name))
1724 return pos;
1725 }
1726 return NULL;
1727 }
1728
1729 struct bpf_map *
1730 bpf_object__find_map_by_offset(struct bpf_object *obj, size_t offset)
1731 {
1732 int i;
1733
1734 for (i = 0; i < obj->nr_maps; i++) {
1735 if (obj->maps[i].offset == offset)
1736 return &obj->maps[i];
1737 }
1738 return ERR_PTR(-ENOENT);
1739 }
1740
1741 long libbpf_get_error(const void *ptr)
1742 {
1743 if (IS_ERR(ptr))
1744 return PTR_ERR(ptr);
1745 return 0;
1746 }
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