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