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25#include <stdlib.h>
26#include <stdio.h>
27#include <stdarg.h>
28#include <libgen.h>
29#include <inttypes.h>
30#include <string.h>
31#include <unistd.h>
32#include <fcntl.h>
33#include <errno.h>
34#include <perf-sys.h>
35#include <asm/unistd.h>
36#include <linux/err.h>
37#include <linux/kernel.h>
38#include <linux/bpf.h>
39#include <linux/btf.h>
40#include <linux/list.h>
41#include <linux/limits.h>
42#include <sys/stat.h>
43#include <sys/types.h>
44#include <sys/vfs.h>
45#include <libelf.h>
46#include <gelf.h>
47
48#include "libbpf.h"
49#include "bpf.h"
50#include "btf.h"
51
52#ifndef EM_BPF
53#define EM_BPF 247
54#endif
55
56#ifndef BPF_FS_MAGIC
57#define BPF_FS_MAGIC 0xcafe4a11
58#endif
59
60#define __printf(a, b) __attribute__((format(printf, a, b)))
61
62__printf(1, 2)
63static int __base_pr(const char *format, ...)
64{
65 va_list args;
66 int err;
67
68 va_start(args, format);
69 err = vfprintf(stderr, format, args);
70 va_end(args);
71 return err;
72}
73
74static __printf(1, 2) libbpf_print_fn_t __pr_warning = __base_pr;
75static __printf(1, 2) libbpf_print_fn_t __pr_info = __base_pr;
76static __printf(1, 2) libbpf_print_fn_t __pr_debug;
77
78#define __pr(func, fmt, ...) \
79do { \
80 if ((func)) \
81 (func)("libbpf: " fmt, ##__VA_ARGS__); \
82} while (0)
83
84#define pr_warning(fmt, ...) __pr(__pr_warning, fmt, ##__VA_ARGS__)
85#define pr_info(fmt, ...) __pr(__pr_info, fmt, ##__VA_ARGS__)
86#define pr_debug(fmt, ...) __pr(__pr_debug, fmt, ##__VA_ARGS__)
87
88void libbpf_set_print(libbpf_print_fn_t warn,
89 libbpf_print_fn_t info,
90 libbpf_print_fn_t debug)
91{
92 __pr_warning = warn;
93 __pr_info = info;
94 __pr_debug = debug;
95}
96
97#define STRERR_BUFSIZE 128
98
99#define ERRNO_OFFSET(e) ((e) - __LIBBPF_ERRNO__START)
100#define ERRCODE_OFFSET(c) ERRNO_OFFSET(LIBBPF_ERRNO__##c)
101#define NR_ERRNO (__LIBBPF_ERRNO__END - __LIBBPF_ERRNO__START)
102
103static const char *libbpf_strerror_table[NR_ERRNO] = {
104 [ERRCODE_OFFSET(LIBELF)] = "Something wrong in libelf",
105 [ERRCODE_OFFSET(FORMAT)] = "BPF object format invalid",
106 [ERRCODE_OFFSET(KVERSION)] = "'version' section incorrect or lost",
107 [ERRCODE_OFFSET(ENDIAN)] = "Endian mismatch",
108 [ERRCODE_OFFSET(INTERNAL)] = "Internal error in libbpf",
109 [ERRCODE_OFFSET(RELOC)] = "Relocation failed",
110 [ERRCODE_OFFSET(VERIFY)] = "Kernel verifier blocks program loading",
111 [ERRCODE_OFFSET(PROG2BIG)] = "Program too big",
112 [ERRCODE_OFFSET(KVER)] = "Incorrect kernel version",
113 [ERRCODE_OFFSET(PROGTYPE)] = "Kernel doesn't support this program type",
114 [ERRCODE_OFFSET(WRNGPID)] = "Wrong pid in netlink message",
115 [ERRCODE_OFFSET(INVSEQ)] = "Invalid netlink sequence",
116};
117
118int libbpf_strerror(int err, char *buf, size_t size)
119{
120 if (!buf || !size)
121 return -1;
122
123 err = err > 0 ? err : -err;
124
125 if (err < __LIBBPF_ERRNO__START) {
126 int ret;
127
128 ret = strerror_r(err, buf, size);
129 buf[size - 1] = '\0';
130 return ret;
131 }
132
133 if (err < __LIBBPF_ERRNO__END) {
134 const char *msg;
135
136 msg = libbpf_strerror_table[ERRNO_OFFSET(err)];
137 snprintf(buf, size, "%s", msg);
138 buf[size - 1] = '\0';
139 return 0;
140 }
141
142 snprintf(buf, size, "Unknown libbpf error %d", err);
143 buf[size - 1] = '\0';
144 return -1;
145}
146
147#define CHECK_ERR(action, err, out) do { \
148 err = action; \
149 if (err) \
150 goto out; \
151} while(0)
152
153
154
155#ifndef zfree
156# define zfree(ptr) ({ free(*ptr); *ptr = NULL; })
157#endif
158
159#ifndef zclose
160# define zclose(fd) ({ \
161 int ___err = 0; \
162 if ((fd) >= 0) \
163 ___err = close((fd)); \
164 fd = -1; \
165 ___err; })
166#endif
167
168#ifdef HAVE_LIBELF_MMAP_SUPPORT
169# define LIBBPF_ELF_C_READ_MMAP ELF_C_READ_MMAP
170#else
171# define LIBBPF_ELF_C_READ_MMAP ELF_C_READ
172#endif
173
174
175
176
177
178struct bpf_program {
179
180 int idx;
181 char *name;
182 int prog_ifindex;
183 char *section_name;
184 struct bpf_insn *insns;
185 size_t insns_cnt, main_prog_cnt;
186 enum bpf_prog_type type;
187
188 struct reloc_desc {
189 enum {
190 RELO_LD64,
191 RELO_CALL,
192 } type;
193 int insn_idx;
194 union {
195 int map_idx;
196 int text_off;
197 };
198 } *reloc_desc;
199 int nr_reloc;
200
201 struct {
202 int nr;
203 int *fds;
204 } instances;
205 bpf_program_prep_t preprocessor;
206
207 struct bpf_object *obj;
208 void *priv;
209 bpf_program_clear_priv_t clear_priv;
210
211 enum bpf_attach_type expected_attach_type;
212};
213
214struct bpf_map {
215 int fd;
216 char *name;
217 size_t offset;
218 int map_ifindex;
219 struct bpf_map_def def;
220 __u32 btf_key_type_id;
221 __u32 btf_value_type_id;
222 void *priv;
223 bpf_map_clear_priv_t clear_priv;
224};
225
226static LIST_HEAD(bpf_objects_list);
227
228struct bpf_object {
229 char license[64];
230 u32 kern_version;
231
232 struct bpf_program *programs;
233 size_t nr_programs;
234 struct bpf_map *maps;
235 size_t nr_maps;
236
237 bool loaded;
238
239
240
241
242
243 struct {
244 int fd;
245 void *obj_buf;
246 size_t obj_buf_sz;
247 Elf *elf;
248 GElf_Ehdr ehdr;
249 Elf_Data *symbols;
250 size_t strtabidx;
251 struct {
252 GElf_Shdr shdr;
253 Elf_Data *data;
254 } *reloc;
255 int nr_reloc;
256 int maps_shndx;
257 int text_shndx;
258 } efile;
259
260
261
262
263
264 struct list_head list;
265
266 struct btf *btf;
267
268 void *priv;
269 bpf_object_clear_priv_t clear_priv;
270
271 char path[];
272};
273#define obj_elf_valid(o) ((o)->efile.elf)
274
275static void bpf_program__unload(struct bpf_program *prog)
276{
277 int i;
278
279 if (!prog)
280 return;
281
282
283
284
285
286 if (prog->instances.nr > 0) {
287 for (i = 0; i < prog->instances.nr; i++)
288 zclose(prog->instances.fds[i]);
289 } else if (prog->instances.nr != -1) {
290 pr_warning("Internal error: instances.nr is %d\n",
291 prog->instances.nr);
292 }
293
294 prog->instances.nr = -1;
295 zfree(&prog->instances.fds);
296}
297
298static void bpf_program__exit(struct bpf_program *prog)
299{
300 if (!prog)
301 return;
302
303 if (prog->clear_priv)
304 prog->clear_priv(prog, prog->priv);
305
306 prog->priv = NULL;
307 prog->clear_priv = NULL;
308
309 bpf_program__unload(prog);
310 zfree(&prog->name);
311 zfree(&prog->section_name);
312 zfree(&prog->insns);
313 zfree(&prog->reloc_desc);
314
315 prog->nr_reloc = 0;
316 prog->insns_cnt = 0;
317 prog->idx = -1;
318}
319
320static int
321bpf_program__init(void *data, size_t size, char *section_name, int idx,
322 struct bpf_program *prog)
323{
324 if (size < sizeof(struct bpf_insn)) {
325 pr_warning("corrupted section '%s'\n", section_name);
326 return -EINVAL;
327 }
328
329 bzero(prog, sizeof(*prog));
330
331 prog->section_name = strdup(section_name);
332 if (!prog->section_name) {
333 pr_warning("failed to alloc name for prog under section(%d) %s\n",
334 idx, section_name);
335 goto errout;
336 }
337
338 prog->insns = malloc(size);
339 if (!prog->insns) {
340 pr_warning("failed to alloc insns for prog under section %s\n",
341 section_name);
342 goto errout;
343 }
344 prog->insns_cnt = size / sizeof(struct bpf_insn);
345 memcpy(prog->insns, data,
346 prog->insns_cnt * sizeof(struct bpf_insn));
347 prog->idx = idx;
348 prog->instances.fds = NULL;
349 prog->instances.nr = -1;
350 prog->type = BPF_PROG_TYPE_KPROBE;
351
352 return 0;
353errout:
354 bpf_program__exit(prog);
355 return -ENOMEM;
356}
357
358static int
359bpf_object__add_program(struct bpf_object *obj, void *data, size_t size,
360 char *section_name, int idx)
361{
362 struct bpf_program prog, *progs;
363 int nr_progs, err;
364
365 err = bpf_program__init(data, size, section_name, idx, &prog);
366 if (err)
367 return err;
368
369 progs = obj->programs;
370 nr_progs = obj->nr_programs;
371
372 progs = realloc(progs, sizeof(progs[0]) * (nr_progs + 1));
373 if (!progs) {
374
375
376
377
378
379 pr_warning("failed to alloc a new program under section '%s'\n",
380 section_name);
381 bpf_program__exit(&prog);
382 return -ENOMEM;
383 }
384
385 pr_debug("found program %s\n", prog.section_name);
386 obj->programs = progs;
387 obj->nr_programs = nr_progs + 1;
388 prog.obj = obj;
389 progs[nr_progs] = prog;
390 return 0;
391}
392
393static int
394bpf_object__init_prog_names(struct bpf_object *obj)
395{
396 Elf_Data *symbols = obj->efile.symbols;
397 struct bpf_program *prog;
398 size_t pi, si;
399
400 for (pi = 0; pi < obj->nr_programs; pi++) {
401 const char *name = NULL;
402
403 prog = &obj->programs[pi];
404 if (prog->idx == obj->efile.text_shndx) {
405 name = ".text";
406 goto skip_search;
407 }
408
409 for (si = 0; si < symbols->d_size / sizeof(GElf_Sym) && !name;
410 si++) {
411 GElf_Sym sym;
412
413 if (!gelf_getsym(symbols, si, &sym))
414 continue;
415 if (sym.st_shndx != prog->idx)
416 continue;
417 if (GELF_ST_BIND(sym.st_info) != STB_GLOBAL)
418 continue;
419
420 name = elf_strptr(obj->efile.elf,
421 obj->efile.strtabidx,
422 sym.st_name);
423 if (!name) {
424 pr_warning("failed to get sym name string for prog %s\n",
425 prog->section_name);
426 return -LIBBPF_ERRNO__LIBELF;
427 }
428 }
429
430 if (!name) {
431 pr_warning("failed to find sym for prog %s\n",
432 prog->section_name);
433 return -EINVAL;
434 }
435skip_search:
436 prog->name = strdup(name);
437 if (!prog->name) {
438 pr_warning("failed to allocate memory for prog sym %s\n",
439 name);
440 return -ENOMEM;
441 }
442 }
443
444 return 0;
445}
446
447static struct bpf_object *bpf_object__new(const char *path,
448 void *obj_buf,
449 size_t obj_buf_sz)
450{
451 struct bpf_object *obj;
452
453 obj = calloc(1, sizeof(struct bpf_object) + strlen(path) + 1);
454 if (!obj) {
455 pr_warning("alloc memory failed for %s\n", path);
456 return ERR_PTR(-ENOMEM);
457 }
458
459 strcpy(obj->path, path);
460 obj->efile.fd = -1;
461
462
463
464
465
466
467
468 obj->efile.obj_buf = obj_buf;
469 obj->efile.obj_buf_sz = obj_buf_sz;
470 obj->efile.maps_shndx = -1;
471
472 obj->loaded = false;
473
474 INIT_LIST_HEAD(&obj->list);
475 list_add(&obj->list, &bpf_objects_list);
476 return obj;
477}
478
479static void bpf_object__elf_finish(struct bpf_object *obj)
480{
481 if (!obj_elf_valid(obj))
482 return;
483
484 if (obj->efile.elf) {
485 elf_end(obj->efile.elf);
486 obj->efile.elf = NULL;
487 }
488 obj->efile.symbols = NULL;
489
490 zfree(&obj->efile.reloc);
491 obj->efile.nr_reloc = 0;
492 zclose(obj->efile.fd);
493 obj->efile.obj_buf = NULL;
494 obj->efile.obj_buf_sz = 0;
495}
496
497static int bpf_object__elf_init(struct bpf_object *obj)
498{
499 int err = 0;
500 GElf_Ehdr *ep;
501
502 if (obj_elf_valid(obj)) {
503 pr_warning("elf init: internal error\n");
504 return -LIBBPF_ERRNO__LIBELF;
505 }
506
507 if (obj->efile.obj_buf_sz > 0) {
508
509
510
511
512 obj->efile.elf = elf_memory(obj->efile.obj_buf,
513 obj->efile.obj_buf_sz);
514 } else {
515 obj->efile.fd = open(obj->path, O_RDONLY);
516 if (obj->efile.fd < 0) {
517 pr_warning("failed to open %s: %s\n", obj->path,
518 strerror(errno));
519 return -errno;
520 }
521
522 obj->efile.elf = elf_begin(obj->efile.fd,
523 LIBBPF_ELF_C_READ_MMAP,
524 NULL);
525 }
526
527 if (!obj->efile.elf) {
528 pr_warning("failed to open %s as ELF file\n",
529 obj->path);
530 err = -LIBBPF_ERRNO__LIBELF;
531 goto errout;
532 }
533
534 if (!gelf_getehdr(obj->efile.elf, &obj->efile.ehdr)) {
535 pr_warning("failed to get EHDR from %s\n",
536 obj->path);
537 err = -LIBBPF_ERRNO__FORMAT;
538 goto errout;
539 }
540 ep = &obj->efile.ehdr;
541
542
543 if ((ep->e_type != ET_REL) || (ep->e_machine && (ep->e_machine != EM_BPF))) {
544 pr_warning("%s is not an eBPF object file\n",
545 obj->path);
546 err = -LIBBPF_ERRNO__FORMAT;
547 goto errout;
548 }
549
550 return 0;
551errout:
552 bpf_object__elf_finish(obj);
553 return err;
554}
555
556static int
557bpf_object__check_endianness(struct bpf_object *obj)
558{
559 static unsigned int const endian = 1;
560
561 switch (obj->efile.ehdr.e_ident[EI_DATA]) {
562 case ELFDATA2LSB:
563
564 if (*(unsigned char const *)&endian != 1)
565 goto mismatch;
566 break;
567
568 case ELFDATA2MSB:
569
570 if (*(unsigned char const *)&endian != 0)
571 goto mismatch;
572 break;
573 default:
574 return -LIBBPF_ERRNO__ENDIAN;
575 }
576
577 return 0;
578
579mismatch:
580 pr_warning("Error: endianness mismatch.\n");
581 return -LIBBPF_ERRNO__ENDIAN;
582}
583
584static int
585bpf_object__init_license(struct bpf_object *obj,
586 void *data, size_t size)
587{
588 memcpy(obj->license, data,
589 min(size, sizeof(obj->license) - 1));
590 pr_debug("license of %s is %s\n", obj->path, obj->license);
591 return 0;
592}
593
594static int
595bpf_object__init_kversion(struct bpf_object *obj,
596 void *data, size_t size)
597{
598 u32 kver;
599
600 if (size != sizeof(kver)) {
601 pr_warning("invalid kver section in %s\n", obj->path);
602 return -LIBBPF_ERRNO__FORMAT;
603 }
604 memcpy(&kver, data, sizeof(kver));
605 obj->kern_version = kver;
606 pr_debug("kernel version of %s is %x\n", obj->path,
607 obj->kern_version);
608 return 0;
609}
610
611static int compare_bpf_map(const void *_a, const void *_b)
612{
613 const struct bpf_map *a = _a;
614 const struct bpf_map *b = _b;
615
616 return a->offset - b->offset;
617}
618
619static int
620bpf_object__init_maps(struct bpf_object *obj)
621{
622 int i, map_idx, map_def_sz, nr_maps = 0;
623 Elf_Scn *scn;
624 Elf_Data *data;
625 Elf_Data *symbols = obj->efile.symbols;
626
627 if (obj->efile.maps_shndx < 0)
628 return -EINVAL;
629 if (!symbols)
630 return -EINVAL;
631
632 scn = elf_getscn(obj->efile.elf, obj->efile.maps_shndx);
633 if (scn)
634 data = elf_getdata(scn, NULL);
635 if (!scn || !data) {
636 pr_warning("failed to get Elf_Data from map section %d\n",
637 obj->efile.maps_shndx);
638 return -EINVAL;
639 }
640
641
642
643
644
645
646
647
648 for (i = 0; i < symbols->d_size / sizeof(GElf_Sym); i++) {
649 GElf_Sym sym;
650
651 if (!gelf_getsym(symbols, i, &sym))
652 continue;
653 if (sym.st_shndx != obj->efile.maps_shndx)
654 continue;
655 nr_maps++;
656 }
657
658
659 pr_debug("maps in %s: %d maps in %zd bytes\n", obj->path,
660 nr_maps, data->d_size);
661
662 if (!nr_maps)
663 return 0;
664
665
666 map_def_sz = data->d_size / nr_maps;
667 if (!data->d_size || (data->d_size % nr_maps) != 0) {
668 pr_warning("unable to determine map definition size "
669 "section %s, %d maps in %zd bytes\n",
670 obj->path, nr_maps, data->d_size);
671 return -EINVAL;
672 }
673
674 obj->maps = calloc(nr_maps, sizeof(obj->maps[0]));
675 if (!obj->maps) {
676 pr_warning("alloc maps for object failed\n");
677 return -ENOMEM;
678 }
679 obj->nr_maps = nr_maps;
680
681
682
683
684
685
686 for (i = 0; i < nr_maps; i++)
687 obj->maps[i].fd = -1;
688
689
690
691
692 for (i = 0, map_idx = 0; i < symbols->d_size / sizeof(GElf_Sym); i++) {
693 GElf_Sym sym;
694 const char *map_name;
695 struct bpf_map_def *def;
696
697 if (!gelf_getsym(symbols, i, &sym))
698 continue;
699 if (sym.st_shndx != obj->efile.maps_shndx)
700 continue;
701
702 map_name = elf_strptr(obj->efile.elf,
703 obj->efile.strtabidx,
704 sym.st_name);
705 obj->maps[map_idx].offset = sym.st_value;
706 if (sym.st_value + map_def_sz > data->d_size) {
707 pr_warning("corrupted maps section in %s: last map \"%s\" too small\n",
708 obj->path, map_name);
709 return -EINVAL;
710 }
711
712 obj->maps[map_idx].name = strdup(map_name);
713 if (!obj->maps[map_idx].name) {
714 pr_warning("failed to alloc map name\n");
715 return -ENOMEM;
716 }
717 pr_debug("map %d is \"%s\"\n", map_idx,
718 obj->maps[map_idx].name);
719 def = (struct bpf_map_def *)(data->d_buf + sym.st_value);
720
721
722
723
724
725
726 if (map_def_sz <= sizeof(struct bpf_map_def)) {
727 memcpy(&obj->maps[map_idx].def, def, map_def_sz);
728 } else {
729
730
731
732
733
734
735 char *b;
736 for (b = ((char *)def) + sizeof(struct bpf_map_def);
737 b < ((char *)def) + map_def_sz; b++) {
738 if (*b != 0) {
739 pr_warning("maps section in %s: \"%s\" "
740 "has unrecognized, non-zero "
741 "options\n",
742 obj->path, map_name);
743 return -EINVAL;
744 }
745 }
746 memcpy(&obj->maps[map_idx].def, def,
747 sizeof(struct bpf_map_def));
748 }
749 map_idx++;
750 }
751
752 qsort(obj->maps, obj->nr_maps, sizeof(obj->maps[0]), compare_bpf_map);
753 return 0;
754}
755
756static bool section_have_execinstr(struct bpf_object *obj, int idx)
757{
758 Elf_Scn *scn;
759 GElf_Shdr sh;
760
761 scn = elf_getscn(obj->efile.elf, idx);
762 if (!scn)
763 return false;
764
765 if (gelf_getshdr(scn, &sh) != &sh)
766 return false;
767
768 if (sh.sh_flags & SHF_EXECINSTR)
769 return true;
770
771 return false;
772}
773
774static int bpf_object__elf_collect(struct bpf_object *obj)
775{
776 Elf *elf = obj->efile.elf;
777 GElf_Ehdr *ep = &obj->efile.ehdr;
778 Elf_Scn *scn = NULL;
779 int idx = 0, err = 0;
780
781
782 if (!elf_rawdata(elf_getscn(elf, ep->e_shstrndx), NULL)) {
783 pr_warning("failed to get e_shstrndx from %s\n",
784 obj->path);
785 return -LIBBPF_ERRNO__FORMAT;
786 }
787
788 while ((scn = elf_nextscn(elf, scn)) != NULL) {
789 char *name;
790 GElf_Shdr sh;
791 Elf_Data *data;
792
793 idx++;
794 if (gelf_getshdr(scn, &sh) != &sh) {
795 pr_warning("failed to get section(%d) header from %s\n",
796 idx, obj->path);
797 err = -LIBBPF_ERRNO__FORMAT;
798 goto out;
799 }
800
801 name = elf_strptr(elf, ep->e_shstrndx, sh.sh_name);
802 if (!name) {
803 pr_warning("failed to get section(%d) name from %s\n",
804 idx, obj->path);
805 err = -LIBBPF_ERRNO__FORMAT;
806 goto out;
807 }
808
809 data = elf_getdata(scn, 0);
810 if (!data) {
811 pr_warning("failed to get section(%d) data from %s(%s)\n",
812 idx, name, obj->path);
813 err = -LIBBPF_ERRNO__FORMAT;
814 goto out;
815 }
816 pr_debug("section(%d) %s, size %ld, link %d, flags %lx, type=%d\n",
817 idx, name, (unsigned long)data->d_size,
818 (int)sh.sh_link, (unsigned long)sh.sh_flags,
819 (int)sh.sh_type);
820
821 if (strcmp(name, "license") == 0)
822 err = bpf_object__init_license(obj,
823 data->d_buf,
824 data->d_size);
825 else if (strcmp(name, "version") == 0)
826 err = bpf_object__init_kversion(obj,
827 data->d_buf,
828 data->d_size);
829 else if (strcmp(name, "maps") == 0)
830 obj->efile.maps_shndx = idx;
831 else if (strcmp(name, BTF_ELF_SEC) == 0) {
832 obj->btf = btf__new(data->d_buf, data->d_size,
833 __pr_debug);
834 if (IS_ERR(obj->btf)) {
835 pr_warning("Error loading ELF section %s: %ld. Ignored and continue.\n",
836 BTF_ELF_SEC, PTR_ERR(obj->btf));
837 obj->btf = NULL;
838 }
839 } else if (sh.sh_type == SHT_SYMTAB) {
840 if (obj->efile.symbols) {
841 pr_warning("bpf: multiple SYMTAB in %s\n",
842 obj->path);
843 err = -LIBBPF_ERRNO__FORMAT;
844 } else {
845 obj->efile.symbols = data;
846 obj->efile.strtabidx = sh.sh_link;
847 }
848 } else if ((sh.sh_type == SHT_PROGBITS) &&
849 (sh.sh_flags & SHF_EXECINSTR) &&
850 (data->d_size > 0)) {
851 if (strcmp(name, ".text") == 0)
852 obj->efile.text_shndx = idx;
853 err = bpf_object__add_program(obj, data->d_buf,
854 data->d_size, name, idx);
855 if (err) {
856 char errmsg[STRERR_BUFSIZE];
857
858 strerror_r(-err, errmsg, sizeof(errmsg));
859 pr_warning("failed to alloc program %s (%s): %s",
860 name, obj->path, errmsg);
861 }
862 } else if (sh.sh_type == SHT_REL) {
863 void *reloc = obj->efile.reloc;
864 int nr_reloc = obj->efile.nr_reloc + 1;
865 int sec = sh.sh_info;
866
867
868 if (!section_have_execinstr(obj, sec)) {
869 pr_debug("skip relo %s(%d) for section(%d)\n",
870 name, idx, sec);
871 continue;
872 }
873
874 reloc = realloc(reloc,
875 sizeof(*obj->efile.reloc) * nr_reloc);
876 if (!reloc) {
877 pr_warning("realloc failed\n");
878 err = -ENOMEM;
879 } else {
880 int n = nr_reloc - 1;
881
882 obj->efile.reloc = reloc;
883 obj->efile.nr_reloc = nr_reloc;
884
885 obj->efile.reloc[n].shdr = sh;
886 obj->efile.reloc[n].data = data;
887 }
888 } else {
889 pr_debug("skip section(%d) %s\n", idx, name);
890 }
891 if (err)
892 goto out;
893 }
894
895 if (!obj->efile.strtabidx || obj->efile.strtabidx >= idx) {
896 pr_warning("Corrupted ELF file: index of strtab invalid\n");
897 return LIBBPF_ERRNO__FORMAT;
898 }
899 if (obj->efile.maps_shndx >= 0) {
900 err = bpf_object__init_maps(obj);
901 if (err)
902 goto out;
903 }
904 err = bpf_object__init_prog_names(obj);
905out:
906 return err;
907}
908
909static struct bpf_program *
910bpf_object__find_prog_by_idx(struct bpf_object *obj, int idx)
911{
912 struct bpf_program *prog;
913 size_t i;
914
915 for (i = 0; i < obj->nr_programs; i++) {
916 prog = &obj->programs[i];
917 if (prog->idx == idx)
918 return prog;
919 }
920 return NULL;
921}
922
923static int
924bpf_program__collect_reloc(struct bpf_program *prog, GElf_Shdr *shdr,
925 Elf_Data *data, struct bpf_object *obj)
926{
927 Elf_Data *symbols = obj->efile.symbols;
928 int text_shndx = obj->efile.text_shndx;
929 int maps_shndx = obj->efile.maps_shndx;
930 struct bpf_map *maps = obj->maps;
931 size_t nr_maps = obj->nr_maps;
932 int i, nrels;
933
934 pr_debug("collecting relocating info for: '%s'\n",
935 prog->section_name);
936 nrels = shdr->sh_size / shdr->sh_entsize;
937
938 prog->reloc_desc = malloc(sizeof(*prog->reloc_desc) * nrels);
939 if (!prog->reloc_desc) {
940 pr_warning("failed to alloc memory in relocation\n");
941 return -ENOMEM;
942 }
943 prog->nr_reloc = nrels;
944
945 for (i = 0; i < nrels; i++) {
946 GElf_Sym sym;
947 GElf_Rel rel;
948 unsigned int insn_idx;
949 struct bpf_insn *insns = prog->insns;
950 size_t map_idx;
951
952 if (!gelf_getrel(data, i, &rel)) {
953 pr_warning("relocation: failed to get %d reloc\n", i);
954 return -LIBBPF_ERRNO__FORMAT;
955 }
956
957 if (!gelf_getsym(symbols,
958 GELF_R_SYM(rel.r_info),
959 &sym)) {
960 pr_warning("relocation: symbol %"PRIx64" not found\n",
961 GELF_R_SYM(rel.r_info));
962 return -LIBBPF_ERRNO__FORMAT;
963 }
964 pr_debug("relo for %lld value %lld name %d\n",
965 (long long) (rel.r_info >> 32),
966 (long long) sym.st_value, sym.st_name);
967
968 if (sym.st_shndx != maps_shndx && sym.st_shndx != text_shndx) {
969 pr_warning("Program '%s' contains non-map related relo data pointing to section %u\n",
970 prog->section_name, sym.st_shndx);
971 return -LIBBPF_ERRNO__RELOC;
972 }
973
974 insn_idx = rel.r_offset / sizeof(struct bpf_insn);
975 pr_debug("relocation: insn_idx=%u\n", insn_idx);
976
977 if (insns[insn_idx].code == (BPF_JMP | BPF_CALL)) {
978 if (insns[insn_idx].src_reg != BPF_PSEUDO_CALL) {
979 pr_warning("incorrect bpf_call opcode\n");
980 return -LIBBPF_ERRNO__RELOC;
981 }
982 prog->reloc_desc[i].type = RELO_CALL;
983 prog->reloc_desc[i].insn_idx = insn_idx;
984 prog->reloc_desc[i].text_off = sym.st_value;
985 continue;
986 }
987
988 if (insns[insn_idx].code != (BPF_LD | BPF_IMM | BPF_DW)) {
989 pr_warning("bpf: relocation: invalid relo for insns[%d].code 0x%x\n",
990 insn_idx, insns[insn_idx].code);
991 return -LIBBPF_ERRNO__RELOC;
992 }
993
994
995 for (map_idx = 0; map_idx < nr_maps; map_idx++) {
996 if (maps[map_idx].offset == sym.st_value) {
997 pr_debug("relocation: find map %zd (%s) for insn %u\n",
998 map_idx, maps[map_idx].name, insn_idx);
999 break;
1000 }
1001 }
1002
1003 if (map_idx >= nr_maps) {
1004 pr_warning("bpf relocation: map_idx %d large than %d\n",
1005 (int)map_idx, (int)nr_maps - 1);
1006 return -LIBBPF_ERRNO__RELOC;
1007 }
1008
1009 prog->reloc_desc[i].type = RELO_LD64;
1010 prog->reloc_desc[i].insn_idx = insn_idx;
1011 prog->reloc_desc[i].map_idx = map_idx;
1012 }
1013 return 0;
1014}
1015
1016static int bpf_map_find_btf_info(struct bpf_map *map, const struct btf *btf)
1017{
1018 const struct btf_type *container_type;
1019 const struct btf_member *key, *value;
1020 struct bpf_map_def *def = &map->def;
1021 const size_t max_name = 256;
1022 char container_name[max_name];
1023 __s64 key_size, value_size;
1024 __s32 container_id;
1025
1026 if (snprintf(container_name, max_name, "____btf_map_%s", map->name) ==
1027 max_name) {
1028 pr_warning("map:%s length of '____btf_map_%s' is too long\n",
1029 map->name, map->name);
1030 return -EINVAL;
1031 }
1032
1033 container_id = btf__find_by_name(btf, container_name);
1034 if (container_id < 0) {
1035 pr_debug("map:%s container_name:%s cannot be found in BTF. Missing BPF_ANNOTATE_KV_PAIR?\n",
1036 map->name, container_name);
1037 return container_id;
1038 }
1039
1040 container_type = btf__type_by_id(btf, container_id);
1041 if (!container_type) {
1042 pr_warning("map:%s cannot find BTF type for container_id:%u\n",
1043 map->name, container_id);
1044 return -EINVAL;
1045 }
1046
1047 if (BTF_INFO_KIND(container_type->info) != BTF_KIND_STRUCT ||
1048 BTF_INFO_VLEN(container_type->info) < 2) {
1049 pr_warning("map:%s container_name:%s is an invalid container struct\n",
1050 map->name, container_name);
1051 return -EINVAL;
1052 }
1053
1054 key = (struct btf_member *)(container_type + 1);
1055 value = key + 1;
1056
1057 key_size = btf__resolve_size(btf, key->type);
1058 if (key_size < 0) {
1059 pr_warning("map:%s invalid BTF key_type_size\n",
1060 map->name);
1061 return key_size;
1062 }
1063
1064 if (def->key_size != key_size) {
1065 pr_warning("map:%s btf_key_type_size:%u != map_def_key_size:%u\n",
1066 map->name, (__u32)key_size, def->key_size);
1067 return -EINVAL;
1068 }
1069
1070 value_size = btf__resolve_size(btf, value->type);
1071 if (value_size < 0) {
1072 pr_warning("map:%s invalid BTF value_type_size\n", map->name);
1073 return value_size;
1074 }
1075
1076 if (def->value_size != value_size) {
1077 pr_warning("map:%s btf_value_type_size:%u != map_def_value_size:%u\n",
1078 map->name, (__u32)value_size, def->value_size);
1079 return -EINVAL;
1080 }
1081
1082 map->btf_key_type_id = key->type;
1083 map->btf_value_type_id = value->type;
1084
1085 return 0;
1086}
1087
1088static int
1089bpf_object__create_maps(struct bpf_object *obj)
1090{
1091 struct bpf_create_map_attr create_attr = {};
1092 unsigned int i;
1093 int err;
1094
1095 for (i = 0; i < obj->nr_maps; i++) {
1096 struct bpf_map *map = &obj->maps[i];
1097 struct bpf_map_def *def = &map->def;
1098 int *pfd = &map->fd;
1099
1100 create_attr.name = map->name;
1101 create_attr.map_ifindex = map->map_ifindex;
1102 create_attr.map_type = def->type;
1103 create_attr.map_flags = def->map_flags;
1104 create_attr.key_size = def->key_size;
1105 create_attr.value_size = def->value_size;
1106 create_attr.max_entries = def->max_entries;
1107 create_attr.btf_fd = 0;
1108 create_attr.btf_key_type_id = 0;
1109 create_attr.btf_value_type_id = 0;
1110
1111 if (obj->btf && !bpf_map_find_btf_info(map, obj->btf)) {
1112 create_attr.btf_fd = btf__fd(obj->btf);
1113 create_attr.btf_key_type_id = map->btf_key_type_id;
1114 create_attr.btf_value_type_id = map->btf_value_type_id;
1115 }
1116
1117 *pfd = bpf_create_map_xattr(&create_attr);
1118 if (*pfd < 0 && create_attr.btf_key_type_id) {
1119 pr_warning("Error in bpf_create_map_xattr(%s):%s(%d). Retrying without BTF.\n",
1120 map->name, strerror(errno), errno);
1121 create_attr.btf_fd = 0;
1122 create_attr.btf_key_type_id = 0;
1123 create_attr.btf_value_type_id = 0;
1124 map->btf_key_type_id = 0;
1125 map->btf_value_type_id = 0;
1126 *pfd = bpf_create_map_xattr(&create_attr);
1127 }
1128
1129 if (*pfd < 0) {
1130 size_t j;
1131
1132 err = *pfd;
1133 pr_warning("failed to create map (name: '%s'): %s\n",
1134 map->name,
1135 strerror(errno));
1136 for (j = 0; j < i; j++)
1137 zclose(obj->maps[j].fd);
1138 return err;
1139 }
1140 pr_debug("create map %s: fd=%d\n", map->name, *pfd);
1141 }
1142
1143 return 0;
1144}
1145
1146static int
1147bpf_program__reloc_text(struct bpf_program *prog, struct bpf_object *obj,
1148 struct reloc_desc *relo)
1149{
1150 struct bpf_insn *insn, *new_insn;
1151 struct bpf_program *text;
1152 size_t new_cnt;
1153
1154 if (relo->type != RELO_CALL)
1155 return -LIBBPF_ERRNO__RELOC;
1156
1157 if (prog->idx == obj->efile.text_shndx) {
1158 pr_warning("relo in .text insn %d into off %d\n",
1159 relo->insn_idx, relo->text_off);
1160 return -LIBBPF_ERRNO__RELOC;
1161 }
1162
1163 if (prog->main_prog_cnt == 0) {
1164 text = bpf_object__find_prog_by_idx(obj, obj->efile.text_shndx);
1165 if (!text) {
1166 pr_warning("no .text section found yet relo into text exist\n");
1167 return -LIBBPF_ERRNO__RELOC;
1168 }
1169 new_cnt = prog->insns_cnt + text->insns_cnt;
1170 new_insn = realloc(prog->insns, new_cnt * sizeof(*insn));
1171 if (!new_insn) {
1172 pr_warning("oom in prog realloc\n");
1173 return -ENOMEM;
1174 }
1175 memcpy(new_insn + prog->insns_cnt, text->insns,
1176 text->insns_cnt * sizeof(*insn));
1177 prog->insns = new_insn;
1178 prog->main_prog_cnt = prog->insns_cnt;
1179 prog->insns_cnt = new_cnt;
1180 pr_debug("added %zd insn from %s to prog %s\n",
1181 text->insns_cnt, text->section_name,
1182 prog->section_name);
1183 }
1184 insn = &prog->insns[relo->insn_idx];
1185 insn->imm += prog->main_prog_cnt - relo->insn_idx;
1186 return 0;
1187}
1188
1189static int
1190bpf_program__relocate(struct bpf_program *prog, struct bpf_object *obj)
1191{
1192 int i, err;
1193
1194 if (!prog || !prog->reloc_desc)
1195 return 0;
1196
1197 for (i = 0; i < prog->nr_reloc; i++) {
1198 if (prog->reloc_desc[i].type == RELO_LD64) {
1199 struct bpf_insn *insns = prog->insns;
1200 int insn_idx, map_idx;
1201
1202 insn_idx = prog->reloc_desc[i].insn_idx;
1203 map_idx = prog->reloc_desc[i].map_idx;
1204
1205 if (insn_idx >= (int)prog->insns_cnt) {
1206 pr_warning("relocation out of range: '%s'\n",
1207 prog->section_name);
1208 return -LIBBPF_ERRNO__RELOC;
1209 }
1210 insns[insn_idx].src_reg = BPF_PSEUDO_MAP_FD;
1211 insns[insn_idx].imm = obj->maps[map_idx].fd;
1212 } else {
1213 err = bpf_program__reloc_text(prog, obj,
1214 &prog->reloc_desc[i]);
1215 if (err)
1216 return err;
1217 }
1218 }
1219
1220 zfree(&prog->reloc_desc);
1221 prog->nr_reloc = 0;
1222 return 0;
1223}
1224
1225
1226static int
1227bpf_object__relocate(struct bpf_object *obj)
1228{
1229 struct bpf_program *prog;
1230 size_t i;
1231 int err;
1232
1233 for (i = 0; i < obj->nr_programs; i++) {
1234 prog = &obj->programs[i];
1235
1236 err = bpf_program__relocate(prog, obj);
1237 if (err) {
1238 pr_warning("failed to relocate '%s'\n",
1239 prog->section_name);
1240 return err;
1241 }
1242 }
1243 return 0;
1244}
1245
1246static int bpf_object__collect_reloc(struct bpf_object *obj)
1247{
1248 int i, err;
1249
1250 if (!obj_elf_valid(obj)) {
1251 pr_warning("Internal error: elf object is closed\n");
1252 return -LIBBPF_ERRNO__INTERNAL;
1253 }
1254
1255 for (i = 0; i < obj->efile.nr_reloc; i++) {
1256 GElf_Shdr *shdr = &obj->efile.reloc[i].shdr;
1257 Elf_Data *data = obj->efile.reloc[i].data;
1258 int idx = shdr->sh_info;
1259 struct bpf_program *prog;
1260
1261 if (shdr->sh_type != SHT_REL) {
1262 pr_warning("internal error at %d\n", __LINE__);
1263 return -LIBBPF_ERRNO__INTERNAL;
1264 }
1265
1266 prog = bpf_object__find_prog_by_idx(obj, idx);
1267 if (!prog) {
1268 pr_warning("relocation failed: no section(%d)\n", idx);
1269 return -LIBBPF_ERRNO__RELOC;
1270 }
1271
1272 err = bpf_program__collect_reloc(prog,
1273 shdr, data,
1274 obj);
1275 if (err)
1276 return err;
1277 }
1278 return 0;
1279}
1280
1281static int
1282load_program(enum bpf_prog_type type, enum bpf_attach_type expected_attach_type,
1283 const char *name, struct bpf_insn *insns, int insns_cnt,
1284 char *license, u32 kern_version, int *pfd, int prog_ifindex)
1285{
1286 struct bpf_load_program_attr load_attr;
1287 char *log_buf;
1288 int ret;
1289
1290 memset(&load_attr, 0, sizeof(struct bpf_load_program_attr));
1291 load_attr.prog_type = type;
1292 load_attr.expected_attach_type = expected_attach_type;
1293 load_attr.name = name;
1294 load_attr.insns = insns;
1295 load_attr.insns_cnt = insns_cnt;
1296 load_attr.license = license;
1297 load_attr.kern_version = kern_version;
1298 load_attr.prog_ifindex = prog_ifindex;
1299
1300 if (!load_attr.insns || !load_attr.insns_cnt)
1301 return -EINVAL;
1302
1303 log_buf = malloc(BPF_LOG_BUF_SIZE);
1304 if (!log_buf)
1305 pr_warning("Alloc log buffer for bpf loader error, continue without log\n");
1306
1307 ret = bpf_load_program_xattr(&load_attr, log_buf, BPF_LOG_BUF_SIZE);
1308
1309 if (ret >= 0) {
1310 *pfd = ret;
1311 ret = 0;
1312 goto out;
1313 }
1314
1315 ret = -LIBBPF_ERRNO__LOAD;
1316 pr_warning("load bpf program failed: %s\n", strerror(errno));
1317
1318 if (log_buf && log_buf[0] != '\0') {
1319 ret = -LIBBPF_ERRNO__VERIFY;
1320 pr_warning("-- BEGIN DUMP LOG ---\n");
1321 pr_warning("\n%s\n", log_buf);
1322 pr_warning("-- END LOG --\n");
1323 } else if (load_attr.insns_cnt >= BPF_MAXINSNS) {
1324 pr_warning("Program too large (%zu insns), at most %d insns\n",
1325 load_attr.insns_cnt, BPF_MAXINSNS);
1326 ret = -LIBBPF_ERRNO__PROG2BIG;
1327 } else {
1328
1329 if (load_attr.prog_type != BPF_PROG_TYPE_KPROBE) {
1330 int fd;
1331
1332 load_attr.prog_type = BPF_PROG_TYPE_KPROBE;
1333 load_attr.expected_attach_type = 0;
1334 fd = bpf_load_program_xattr(&load_attr, NULL, 0);
1335 if (fd >= 0) {
1336 close(fd);
1337 ret = -LIBBPF_ERRNO__PROGTYPE;
1338 goto out;
1339 }
1340 }
1341
1342 if (log_buf)
1343 ret = -LIBBPF_ERRNO__KVER;
1344 }
1345
1346out:
1347 free(log_buf);
1348 return ret;
1349}
1350
1351static int
1352bpf_program__load(struct bpf_program *prog,
1353 char *license, u32 kern_version)
1354{
1355 int err = 0, fd, i;
1356
1357 if (prog->instances.nr < 0 || !prog->instances.fds) {
1358 if (prog->preprocessor) {
1359 pr_warning("Internal error: can't load program '%s'\n",
1360 prog->section_name);
1361 return -LIBBPF_ERRNO__INTERNAL;
1362 }
1363
1364 prog->instances.fds = malloc(sizeof(int));
1365 if (!prog->instances.fds) {
1366 pr_warning("Not enough memory for BPF fds\n");
1367 return -ENOMEM;
1368 }
1369 prog->instances.nr = 1;
1370 prog->instances.fds[0] = -1;
1371 }
1372
1373 if (!prog->preprocessor) {
1374 if (prog->instances.nr != 1) {
1375 pr_warning("Program '%s' is inconsistent: nr(%d) != 1\n",
1376 prog->section_name, prog->instances.nr);
1377 }
1378 err = load_program(prog->type, prog->expected_attach_type,
1379 prog->name, prog->insns, prog->insns_cnt,
1380 license, kern_version, &fd,
1381 prog->prog_ifindex);
1382 if (!err)
1383 prog->instances.fds[0] = fd;
1384 goto out;
1385 }
1386
1387 for (i = 0; i < prog->instances.nr; i++) {
1388 struct bpf_prog_prep_result result;
1389 bpf_program_prep_t preprocessor = prog->preprocessor;
1390
1391 bzero(&result, sizeof(result));
1392 err = preprocessor(prog, i, prog->insns,
1393 prog->insns_cnt, &result);
1394 if (err) {
1395 pr_warning("Preprocessing the %dth instance of program '%s' failed\n",
1396 i, prog->section_name);
1397 goto out;
1398 }
1399
1400 if (!result.new_insn_ptr || !result.new_insn_cnt) {
1401 pr_debug("Skip loading the %dth instance of program '%s'\n",
1402 i, prog->section_name);
1403 prog->instances.fds[i] = -1;
1404 if (result.pfd)
1405 *result.pfd = -1;
1406 continue;
1407 }
1408
1409 err = load_program(prog->type, prog->expected_attach_type,
1410 prog->name, result.new_insn_ptr,
1411 result.new_insn_cnt,
1412 license, kern_version, &fd,
1413 prog->prog_ifindex);
1414
1415 if (err) {
1416 pr_warning("Loading the %dth instance of program '%s' failed\n",
1417 i, prog->section_name);
1418 goto out;
1419 }
1420
1421 if (result.pfd)
1422 *result.pfd = fd;
1423 prog->instances.fds[i] = fd;
1424 }
1425out:
1426 if (err)
1427 pr_warning("failed to load program '%s'\n",
1428 prog->section_name);
1429 zfree(&prog->insns);
1430 prog->insns_cnt = 0;
1431 return err;
1432}
1433
1434static int
1435bpf_object__load_progs(struct bpf_object *obj)
1436{
1437 size_t i;
1438 int err;
1439
1440 for (i = 0; i < obj->nr_programs; i++) {
1441 if (obj->programs[i].idx == obj->efile.text_shndx)
1442 continue;
1443 err = bpf_program__load(&obj->programs[i],
1444 obj->license,
1445 obj->kern_version);
1446 if (err)
1447 return err;
1448 }
1449 return 0;
1450}
1451
1452static bool bpf_prog_type__needs_kver(enum bpf_prog_type type)
1453{
1454 switch (type) {
1455 case BPF_PROG_TYPE_SOCKET_FILTER:
1456 case BPF_PROG_TYPE_SCHED_CLS:
1457 case BPF_PROG_TYPE_SCHED_ACT:
1458 case BPF_PROG_TYPE_XDP:
1459 case BPF_PROG_TYPE_CGROUP_SKB:
1460 case BPF_PROG_TYPE_CGROUP_SOCK:
1461 case BPF_PROG_TYPE_LWT_IN:
1462 case BPF_PROG_TYPE_LWT_OUT:
1463 case BPF_PROG_TYPE_LWT_XMIT:
1464 case BPF_PROG_TYPE_LWT_SEG6LOCAL:
1465 case BPF_PROG_TYPE_SOCK_OPS:
1466 case BPF_PROG_TYPE_SK_SKB:
1467 case BPF_PROG_TYPE_CGROUP_DEVICE:
1468 case BPF_PROG_TYPE_SK_MSG:
1469 case BPF_PROG_TYPE_CGROUP_SOCK_ADDR:
1470 case BPF_PROG_TYPE_LIRC_MODE2:
1471 return false;
1472 case BPF_PROG_TYPE_UNSPEC:
1473 case BPF_PROG_TYPE_KPROBE:
1474 case BPF_PROG_TYPE_TRACEPOINT:
1475 case BPF_PROG_TYPE_PERF_EVENT:
1476 case BPF_PROG_TYPE_RAW_TRACEPOINT:
1477 default:
1478 return true;
1479 }
1480}
1481
1482static int bpf_object__validate(struct bpf_object *obj, bool needs_kver)
1483{
1484 if (needs_kver && obj->kern_version == 0) {
1485 pr_warning("%s doesn't provide kernel version\n",
1486 obj->path);
1487 return -LIBBPF_ERRNO__KVERSION;
1488 }
1489 return 0;
1490}
1491
1492static struct bpf_object *
1493__bpf_object__open(const char *path, void *obj_buf, size_t obj_buf_sz,
1494 bool needs_kver)
1495{
1496 struct bpf_object *obj;
1497 int err;
1498
1499 if (elf_version(EV_CURRENT) == EV_NONE) {
1500 pr_warning("failed to init libelf for %s\n", path);
1501 return ERR_PTR(-LIBBPF_ERRNO__LIBELF);
1502 }
1503
1504 obj = bpf_object__new(path, obj_buf, obj_buf_sz);
1505 if (IS_ERR(obj))
1506 return obj;
1507
1508 CHECK_ERR(bpf_object__elf_init(obj), err, out);
1509 CHECK_ERR(bpf_object__check_endianness(obj), err, out);
1510 CHECK_ERR(bpf_object__elf_collect(obj), err, out);
1511 CHECK_ERR(bpf_object__collect_reloc(obj), err, out);
1512 CHECK_ERR(bpf_object__validate(obj, needs_kver), err, out);
1513
1514 bpf_object__elf_finish(obj);
1515 return obj;
1516out:
1517 bpf_object__close(obj);
1518 return ERR_PTR(err);
1519}
1520
1521struct bpf_object *bpf_object__open(const char *path)
1522{
1523
1524 if (!path)
1525 return NULL;
1526
1527 pr_debug("loading %s\n", path);
1528
1529 return __bpf_object__open(path, NULL, 0, true);
1530}
1531
1532struct bpf_object *bpf_object__open_buffer(void *obj_buf,
1533 size_t obj_buf_sz,
1534 const char *name)
1535{
1536 char tmp_name[64];
1537
1538
1539 if (!obj_buf || obj_buf_sz <= 0)
1540 return NULL;
1541
1542 if (!name) {
1543 snprintf(tmp_name, sizeof(tmp_name), "%lx-%lx",
1544 (unsigned long)obj_buf,
1545 (unsigned long)obj_buf_sz);
1546 tmp_name[sizeof(tmp_name) - 1] = '\0';
1547 name = tmp_name;
1548 }
1549 pr_debug("loading object '%s' from buffer\n",
1550 name);
1551
1552 return __bpf_object__open(name, obj_buf, obj_buf_sz, true);
1553}
1554
1555int bpf_object__unload(struct bpf_object *obj)
1556{
1557 size_t i;
1558
1559 if (!obj)
1560 return -EINVAL;
1561
1562 for (i = 0; i < obj->nr_maps; i++)
1563 zclose(obj->maps[i].fd);
1564
1565 for (i = 0; i < obj->nr_programs; i++)
1566 bpf_program__unload(&obj->programs[i]);
1567
1568 return 0;
1569}
1570
1571int bpf_object__load(struct bpf_object *obj)
1572{
1573 int err;
1574
1575 if (!obj)
1576 return -EINVAL;
1577
1578 if (obj->loaded) {
1579 pr_warning("object should not be loaded twice\n");
1580 return -EINVAL;
1581 }
1582
1583 obj->loaded = true;
1584
1585 CHECK_ERR(bpf_object__create_maps(obj), err, out);
1586 CHECK_ERR(bpf_object__relocate(obj), err, out);
1587 CHECK_ERR(bpf_object__load_progs(obj), err, out);
1588
1589 return 0;
1590out:
1591 bpf_object__unload(obj);
1592 pr_warning("failed to load object '%s'\n", obj->path);
1593 return err;
1594}
1595
1596static int check_path(const char *path)
1597{
1598 struct statfs st_fs;
1599 char *dname, *dir;
1600 int err = 0;
1601
1602 if (path == NULL)
1603 return -EINVAL;
1604
1605 dname = strdup(path);
1606 if (dname == NULL)
1607 return -ENOMEM;
1608
1609 dir = dirname(dname);
1610 if (statfs(dir, &st_fs)) {
1611 pr_warning("failed to statfs %s: %s\n", dir, strerror(errno));
1612 err = -errno;
1613 }
1614 free(dname);
1615
1616 if (!err && st_fs.f_type != BPF_FS_MAGIC) {
1617 pr_warning("specified path %s is not on BPF FS\n", path);
1618 err = -EINVAL;
1619 }
1620
1621 return err;
1622}
1623
1624int bpf_program__pin_instance(struct bpf_program *prog, const char *path,
1625 int instance)
1626{
1627 int err;
1628
1629 err = check_path(path);
1630 if (err)
1631 return err;
1632
1633 if (prog == NULL) {
1634 pr_warning("invalid program pointer\n");
1635 return -EINVAL;
1636 }
1637
1638 if (instance < 0 || instance >= prog->instances.nr) {
1639 pr_warning("invalid prog instance %d of prog %s (max %d)\n",
1640 instance, prog->section_name, prog->instances.nr);
1641 return -EINVAL;
1642 }
1643
1644 if (bpf_obj_pin(prog->instances.fds[instance], path)) {
1645 pr_warning("failed to pin program: %s\n", strerror(errno));
1646 return -errno;
1647 }
1648 pr_debug("pinned program '%s'\n", path);
1649
1650 return 0;
1651}
1652
1653static int make_dir(const char *path)
1654{
1655 int err = 0;
1656
1657 if (mkdir(path, 0700) && errno != EEXIST)
1658 err = -errno;
1659
1660 if (err)
1661 pr_warning("failed to mkdir %s: %s\n", path, strerror(-err));
1662 return err;
1663}
1664
1665int bpf_program__pin(struct bpf_program *prog, const char *path)
1666{
1667 int i, err;
1668
1669 err = check_path(path);
1670 if (err)
1671 return err;
1672
1673 if (prog == NULL) {
1674 pr_warning("invalid program pointer\n");
1675 return -EINVAL;
1676 }
1677
1678 if (prog->instances.nr <= 0) {
1679 pr_warning("no instances of prog %s to pin\n",
1680 prog->section_name);
1681 return -EINVAL;
1682 }
1683
1684 err = make_dir(path);
1685 if (err)
1686 return err;
1687
1688 for (i = 0; i < prog->instances.nr; i++) {
1689 char buf[PATH_MAX];
1690 int len;
1691
1692 len = snprintf(buf, PATH_MAX, "%s/%d", path, i);
1693 if (len < 0)
1694 return -EINVAL;
1695 else if (len >= PATH_MAX)
1696 return -ENAMETOOLONG;
1697
1698 err = bpf_program__pin_instance(prog, buf, i);
1699 if (err)
1700 return err;
1701 }
1702
1703 return 0;
1704}
1705
1706int bpf_map__pin(struct bpf_map *map, const char *path)
1707{
1708 int err;
1709
1710 err = check_path(path);
1711 if (err)
1712 return err;
1713
1714 if (map == NULL) {
1715 pr_warning("invalid map pointer\n");
1716 return -EINVAL;
1717 }
1718
1719 if (bpf_obj_pin(map->fd, path)) {
1720 pr_warning("failed to pin map: %s\n", strerror(errno));
1721 return -errno;
1722 }
1723
1724 pr_debug("pinned map '%s'\n", path);
1725 return 0;
1726}
1727
1728int bpf_object__pin(struct bpf_object *obj, const char *path)
1729{
1730 struct bpf_program *prog;
1731 struct bpf_map *map;
1732 int err;
1733
1734 if (!obj)
1735 return -ENOENT;
1736
1737 if (!obj->loaded) {
1738 pr_warning("object not yet loaded; load it first\n");
1739 return -ENOENT;
1740 }
1741
1742 err = make_dir(path);
1743 if (err)
1744 return err;
1745
1746 bpf_map__for_each(map, obj) {
1747 char buf[PATH_MAX];
1748 int len;
1749
1750 len = snprintf(buf, PATH_MAX, "%s/%s", path,
1751 bpf_map__name(map));
1752 if (len < 0)
1753 return -EINVAL;
1754 else if (len >= PATH_MAX)
1755 return -ENAMETOOLONG;
1756
1757 err = bpf_map__pin(map, buf);
1758 if (err)
1759 return err;
1760 }
1761
1762 bpf_object__for_each_program(prog, obj) {
1763 char buf[PATH_MAX];
1764 int len;
1765
1766 len = snprintf(buf, PATH_MAX, "%s/%s", path,
1767 prog->section_name);
1768 if (len < 0)
1769 return -EINVAL;
1770 else if (len >= PATH_MAX)
1771 return -ENAMETOOLONG;
1772
1773 err = bpf_program__pin(prog, buf);
1774 if (err)
1775 return err;
1776 }
1777
1778 return 0;
1779}
1780
1781void bpf_object__close(struct bpf_object *obj)
1782{
1783 size_t i;
1784
1785 if (!obj)
1786 return;
1787
1788 if (obj->clear_priv)
1789 obj->clear_priv(obj, obj->priv);
1790
1791 bpf_object__elf_finish(obj);
1792 bpf_object__unload(obj);
1793 btf__free(obj->btf);
1794
1795 for (i = 0; i < obj->nr_maps; i++) {
1796 zfree(&obj->maps[i].name);
1797 if (obj->maps[i].clear_priv)
1798 obj->maps[i].clear_priv(&obj->maps[i],
1799 obj->maps[i].priv);
1800 obj->maps[i].priv = NULL;
1801 obj->maps[i].clear_priv = NULL;
1802 }
1803 zfree(&obj->maps);
1804 obj->nr_maps = 0;
1805
1806 if (obj->programs && obj->nr_programs) {
1807 for (i = 0; i < obj->nr_programs; i++)
1808 bpf_program__exit(&obj->programs[i]);
1809 }
1810 zfree(&obj->programs);
1811
1812 list_del(&obj->list);
1813 free(obj);
1814}
1815
1816struct bpf_object *
1817bpf_object__next(struct bpf_object *prev)
1818{
1819 struct bpf_object *next;
1820
1821 if (!prev)
1822 next = list_first_entry(&bpf_objects_list,
1823 struct bpf_object,
1824 list);
1825 else
1826 next = list_next_entry(prev, list);
1827
1828
1829 if (&next->list == &bpf_objects_list)
1830 return NULL;
1831
1832 return next;
1833}
1834
1835const char *bpf_object__name(struct bpf_object *obj)
1836{
1837 return obj ? obj->path : ERR_PTR(-EINVAL);
1838}
1839
1840unsigned int bpf_object__kversion(struct bpf_object *obj)
1841{
1842 return obj ? obj->kern_version : 0;
1843}
1844
1845int bpf_object__btf_fd(const struct bpf_object *obj)
1846{
1847 return obj->btf ? btf__fd(obj->btf) : -1;
1848}
1849
1850int bpf_object__set_priv(struct bpf_object *obj, void *priv,
1851 bpf_object_clear_priv_t clear_priv)
1852{
1853 if (obj->priv && obj->clear_priv)
1854 obj->clear_priv(obj, obj->priv);
1855
1856 obj->priv = priv;
1857 obj->clear_priv = clear_priv;
1858 return 0;
1859}
1860
1861void *bpf_object__priv(struct bpf_object *obj)
1862{
1863 return obj ? obj->priv : ERR_PTR(-EINVAL);
1864}
1865
1866struct bpf_program *
1867bpf_program__next(struct bpf_program *prev, struct bpf_object *obj)
1868{
1869 size_t idx;
1870
1871 if (!obj->programs)
1872 return NULL;
1873
1874 if (prev == NULL)
1875 return &obj->programs[0];
1876
1877 if (prev->obj != obj) {
1878 pr_warning("error: program handler doesn't match object\n");
1879 return NULL;
1880 }
1881
1882 idx = (prev - obj->programs) + 1;
1883 if (idx >= obj->nr_programs)
1884 return NULL;
1885 return &obj->programs[idx];
1886}
1887
1888int bpf_program__set_priv(struct bpf_program *prog, void *priv,
1889 bpf_program_clear_priv_t clear_priv)
1890{
1891 if (prog->priv && prog->clear_priv)
1892 prog->clear_priv(prog, prog->priv);
1893
1894 prog->priv = priv;
1895 prog->clear_priv = clear_priv;
1896 return 0;
1897}
1898
1899void *bpf_program__priv(struct bpf_program *prog)
1900{
1901 return prog ? prog->priv : ERR_PTR(-EINVAL);
1902}
1903
1904const char *bpf_program__title(struct bpf_program *prog, bool needs_copy)
1905{
1906 const char *title;
1907
1908 title = prog->section_name;
1909 if (needs_copy) {
1910 title = strdup(title);
1911 if (!title) {
1912 pr_warning("failed to strdup program title\n");
1913 return ERR_PTR(-ENOMEM);
1914 }
1915 }
1916
1917 return title;
1918}
1919
1920int bpf_program__fd(struct bpf_program *prog)
1921{
1922 return bpf_program__nth_fd(prog, 0);
1923}
1924
1925int bpf_program__set_prep(struct bpf_program *prog, int nr_instances,
1926 bpf_program_prep_t prep)
1927{
1928 int *instances_fds;
1929
1930 if (nr_instances <= 0 || !prep)
1931 return -EINVAL;
1932
1933 if (prog->instances.nr > 0 || prog->instances.fds) {
1934 pr_warning("Can't set pre-processor after loading\n");
1935 return -EINVAL;
1936 }
1937
1938 instances_fds = malloc(sizeof(int) * nr_instances);
1939 if (!instances_fds) {
1940 pr_warning("alloc memory failed for fds\n");
1941 return -ENOMEM;
1942 }
1943
1944
1945 memset(instances_fds, -1, sizeof(int) * nr_instances);
1946
1947 prog->instances.nr = nr_instances;
1948 prog->instances.fds = instances_fds;
1949 prog->preprocessor = prep;
1950 return 0;
1951}
1952
1953int bpf_program__nth_fd(struct bpf_program *prog, int n)
1954{
1955 int fd;
1956
1957 if (n >= prog->instances.nr || n < 0) {
1958 pr_warning("Can't get the %dth fd from program %s: only %d instances\n",
1959 n, prog->section_name, prog->instances.nr);
1960 return -EINVAL;
1961 }
1962
1963 fd = prog->instances.fds[n];
1964 if (fd < 0) {
1965 pr_warning("%dth instance of program '%s' is invalid\n",
1966 n, prog->section_name);
1967 return -ENOENT;
1968 }
1969
1970 return fd;
1971}
1972
1973void bpf_program__set_type(struct bpf_program *prog, enum bpf_prog_type type)
1974{
1975 prog->type = type;
1976}
1977
1978static bool bpf_program__is_type(struct bpf_program *prog,
1979 enum bpf_prog_type type)
1980{
1981 return prog ? (prog->type == type) : false;
1982}
1983
1984#define BPF_PROG_TYPE_FNS(NAME, TYPE) \
1985int bpf_program__set_##NAME(struct bpf_program *prog) \
1986{ \
1987 if (!prog) \
1988 return -EINVAL; \
1989 bpf_program__set_type(prog, TYPE); \
1990 return 0; \
1991} \
1992 \
1993bool bpf_program__is_##NAME(struct bpf_program *prog) \
1994{ \
1995 return bpf_program__is_type(prog, TYPE); \
1996} \
1997
1998BPF_PROG_TYPE_FNS(socket_filter, BPF_PROG_TYPE_SOCKET_FILTER);
1999BPF_PROG_TYPE_FNS(kprobe, BPF_PROG_TYPE_KPROBE);
2000BPF_PROG_TYPE_FNS(sched_cls, BPF_PROG_TYPE_SCHED_CLS);
2001BPF_PROG_TYPE_FNS(sched_act, BPF_PROG_TYPE_SCHED_ACT);
2002BPF_PROG_TYPE_FNS(tracepoint, BPF_PROG_TYPE_TRACEPOINT);
2003BPF_PROG_TYPE_FNS(raw_tracepoint, BPF_PROG_TYPE_RAW_TRACEPOINT);
2004BPF_PROG_TYPE_FNS(xdp, BPF_PROG_TYPE_XDP);
2005BPF_PROG_TYPE_FNS(perf_event, BPF_PROG_TYPE_PERF_EVENT);
2006
2007void bpf_program__set_expected_attach_type(struct bpf_program *prog,
2008 enum bpf_attach_type type)
2009{
2010 prog->expected_attach_type = type;
2011}
2012
2013#define BPF_PROG_SEC_FULL(string, ptype, atype) \
2014 { string, sizeof(string) - 1, ptype, atype }
2015
2016#define BPF_PROG_SEC(string, ptype) BPF_PROG_SEC_FULL(string, ptype, 0)
2017
2018#define BPF_S_PROG_SEC(string, ptype) \
2019 BPF_PROG_SEC_FULL(string, BPF_PROG_TYPE_CGROUP_SOCK, ptype)
2020
2021#define BPF_SA_PROG_SEC(string, ptype) \
2022 BPF_PROG_SEC_FULL(string, BPF_PROG_TYPE_CGROUP_SOCK_ADDR, ptype)
2023
2024static const struct {
2025 const char *sec;
2026 size_t len;
2027 enum bpf_prog_type prog_type;
2028 enum bpf_attach_type expected_attach_type;
2029} section_names[] = {
2030 BPF_PROG_SEC("socket", BPF_PROG_TYPE_SOCKET_FILTER),
2031 BPF_PROG_SEC("kprobe/", BPF_PROG_TYPE_KPROBE),
2032 BPF_PROG_SEC("kretprobe/", BPF_PROG_TYPE_KPROBE),
2033 BPF_PROG_SEC("classifier", BPF_PROG_TYPE_SCHED_CLS),
2034 BPF_PROG_SEC("action", BPF_PROG_TYPE_SCHED_ACT),
2035 BPF_PROG_SEC("tracepoint/", BPF_PROG_TYPE_TRACEPOINT),
2036 BPF_PROG_SEC("raw_tracepoint/", BPF_PROG_TYPE_RAW_TRACEPOINT),
2037 BPF_PROG_SEC("xdp", BPF_PROG_TYPE_XDP),
2038 BPF_PROG_SEC("perf_event", BPF_PROG_TYPE_PERF_EVENT),
2039 BPF_PROG_SEC("cgroup/skb", BPF_PROG_TYPE_CGROUP_SKB),
2040 BPF_PROG_SEC("cgroup/sock", BPF_PROG_TYPE_CGROUP_SOCK),
2041 BPF_PROG_SEC("cgroup/dev", BPF_PROG_TYPE_CGROUP_DEVICE),
2042 BPF_PROG_SEC("lwt_in", BPF_PROG_TYPE_LWT_IN),
2043 BPF_PROG_SEC("lwt_out", BPF_PROG_TYPE_LWT_OUT),
2044 BPF_PROG_SEC("lwt_xmit", BPF_PROG_TYPE_LWT_XMIT),
2045 BPF_PROG_SEC("sockops", BPF_PROG_TYPE_SOCK_OPS),
2046 BPF_PROG_SEC("sk_skb", BPF_PROG_TYPE_SK_SKB),
2047 BPF_PROG_SEC("sk_msg", BPF_PROG_TYPE_SK_MSG),
2048 BPF_SA_PROG_SEC("cgroup/bind4", BPF_CGROUP_INET4_BIND),
2049 BPF_SA_PROG_SEC("cgroup/bind6", BPF_CGROUP_INET6_BIND),
2050 BPF_SA_PROG_SEC("cgroup/connect4", BPF_CGROUP_INET4_CONNECT),
2051 BPF_SA_PROG_SEC("cgroup/connect6", BPF_CGROUP_INET6_CONNECT),
2052 BPF_SA_PROG_SEC("cgroup/sendmsg4", BPF_CGROUP_UDP4_SENDMSG),
2053 BPF_SA_PROG_SEC("cgroup/sendmsg6", BPF_CGROUP_UDP6_SENDMSG),
2054 BPF_S_PROG_SEC("cgroup/post_bind4", BPF_CGROUP_INET4_POST_BIND),
2055 BPF_S_PROG_SEC("cgroup/post_bind6", BPF_CGROUP_INET6_POST_BIND),
2056};
2057
2058#undef BPF_PROG_SEC
2059#undef BPF_PROG_SEC_FULL
2060#undef BPF_S_PROG_SEC
2061#undef BPF_SA_PROG_SEC
2062
2063static int bpf_program__identify_section(struct bpf_program *prog)
2064{
2065 int i;
2066
2067 if (!prog->section_name)
2068 goto err;
2069
2070 for (i = 0; i < ARRAY_SIZE(section_names); i++)
2071 if (strncmp(prog->section_name, section_names[i].sec,
2072 section_names[i].len) == 0)
2073 return i;
2074
2075err:
2076 pr_warning("failed to guess program type based on section name %s\n",
2077 prog->section_name);
2078
2079 return -1;
2080}
2081
2082int bpf_map__fd(struct bpf_map *map)
2083{
2084 return map ? map->fd : -EINVAL;
2085}
2086
2087const struct bpf_map_def *bpf_map__def(struct bpf_map *map)
2088{
2089 return map ? &map->def : ERR_PTR(-EINVAL);
2090}
2091
2092const char *bpf_map__name(struct bpf_map *map)
2093{
2094 return map ? map->name : NULL;
2095}
2096
2097__u32 bpf_map__btf_key_type_id(const struct bpf_map *map)
2098{
2099 return map ? map->btf_key_type_id : 0;
2100}
2101
2102__u32 bpf_map__btf_value_type_id(const struct bpf_map *map)
2103{
2104 return map ? map->btf_value_type_id : 0;
2105}
2106
2107int bpf_map__set_priv(struct bpf_map *map, void *priv,
2108 bpf_map_clear_priv_t clear_priv)
2109{
2110 if (!map)
2111 return -EINVAL;
2112
2113 if (map->priv) {
2114 if (map->clear_priv)
2115 map->clear_priv(map, map->priv);
2116 }
2117
2118 map->priv = priv;
2119 map->clear_priv = clear_priv;
2120 return 0;
2121}
2122
2123void *bpf_map__priv(struct bpf_map *map)
2124{
2125 return map ? map->priv : ERR_PTR(-EINVAL);
2126}
2127
2128struct bpf_map *
2129bpf_map__next(struct bpf_map *prev, struct bpf_object *obj)
2130{
2131 size_t idx;
2132 struct bpf_map *s, *e;
2133
2134 if (!obj || !obj->maps)
2135 return NULL;
2136
2137 s = obj->maps;
2138 e = obj->maps + obj->nr_maps;
2139
2140 if (prev == NULL)
2141 return s;
2142
2143 if ((prev < s) || (prev >= e)) {
2144 pr_warning("error in %s: map handler doesn't belong to object\n",
2145 __func__);
2146 return NULL;
2147 }
2148
2149 idx = (prev - obj->maps) + 1;
2150 if (idx >= obj->nr_maps)
2151 return NULL;
2152 return &obj->maps[idx];
2153}
2154
2155struct bpf_map *
2156bpf_object__find_map_by_name(struct bpf_object *obj, const char *name)
2157{
2158 struct bpf_map *pos;
2159
2160 bpf_map__for_each(pos, obj) {
2161 if (pos->name && !strcmp(pos->name, name))
2162 return pos;
2163 }
2164 return NULL;
2165}
2166
2167struct bpf_map *
2168bpf_object__find_map_by_offset(struct bpf_object *obj, size_t offset)
2169{
2170 int i;
2171
2172 for (i = 0; i < obj->nr_maps; i++) {
2173 if (obj->maps[i].offset == offset)
2174 return &obj->maps[i];
2175 }
2176 return ERR_PTR(-ENOENT);
2177}
2178
2179long libbpf_get_error(const void *ptr)
2180{
2181 if (IS_ERR(ptr))
2182 return PTR_ERR(ptr);
2183 return 0;
2184}
2185
2186int bpf_prog_load(const char *file, enum bpf_prog_type type,
2187 struct bpf_object **pobj, int *prog_fd)
2188{
2189 struct bpf_prog_load_attr attr;
2190
2191 memset(&attr, 0, sizeof(struct bpf_prog_load_attr));
2192 attr.file = file;
2193 attr.prog_type = type;
2194 attr.expected_attach_type = 0;
2195
2196 return bpf_prog_load_xattr(&attr, pobj, prog_fd);
2197}
2198
2199int bpf_prog_load_xattr(const struct bpf_prog_load_attr *attr,
2200 struct bpf_object **pobj, int *prog_fd)
2201{
2202 struct bpf_program *prog, *first_prog = NULL;
2203 enum bpf_attach_type expected_attach_type;
2204 enum bpf_prog_type prog_type;
2205 struct bpf_object *obj;
2206 struct bpf_map *map;
2207 int section_idx;
2208 int err;
2209
2210 if (!attr)
2211 return -EINVAL;
2212 if (!attr->file)
2213 return -EINVAL;
2214
2215 obj = __bpf_object__open(attr->file, NULL, 0,
2216 bpf_prog_type__needs_kver(attr->prog_type));
2217 if (IS_ERR_OR_NULL(obj))
2218 return -ENOENT;
2219
2220 bpf_object__for_each_program(prog, obj) {
2221
2222
2223
2224
2225 prog_type = attr->prog_type;
2226 prog->prog_ifindex = attr->ifindex;
2227 expected_attach_type = attr->expected_attach_type;
2228 if (prog_type == BPF_PROG_TYPE_UNSPEC) {
2229 section_idx = bpf_program__identify_section(prog);
2230 if (section_idx < 0) {
2231 bpf_object__close(obj);
2232 return -EINVAL;
2233 }
2234 prog_type = section_names[section_idx].prog_type;
2235 expected_attach_type =
2236 section_names[section_idx].expected_attach_type;
2237 }
2238
2239 bpf_program__set_type(prog, prog_type);
2240 bpf_program__set_expected_attach_type(prog,
2241 expected_attach_type);
2242
2243 if (prog->idx != obj->efile.text_shndx && !first_prog)
2244 first_prog = prog;
2245 }
2246
2247 bpf_map__for_each(map, obj) {
2248 map->map_ifindex = attr->ifindex;
2249 }
2250
2251 if (!first_prog) {
2252 pr_warning("object file doesn't contain bpf program\n");
2253 bpf_object__close(obj);
2254 return -ENOENT;
2255 }
2256
2257 err = bpf_object__load(obj);
2258 if (err) {
2259 bpf_object__close(obj);
2260 return -EINVAL;
2261 }
2262
2263 *pobj = obj;
2264 *prog_fd = bpf_program__fd(first_prog);
2265 return 0;
2266}
2267
2268enum bpf_perf_event_ret
2269bpf_perf_event_read_simple(void *mem, unsigned long size,
2270 unsigned long page_size, void **buf, size_t *buf_len,
2271 bpf_perf_event_print_t fn, void *priv)
2272{
2273 volatile struct perf_event_mmap_page *header = mem;
2274 __u64 data_tail = header->data_tail;
2275 __u64 data_head = header->data_head;
2276 int ret = LIBBPF_PERF_EVENT_ERROR;
2277 void *base, *begin, *end;
2278
2279 asm volatile("" ::: "memory");
2280 if (data_head == data_tail)
2281 return LIBBPF_PERF_EVENT_CONT;
2282
2283 base = ((char *)header) + page_size;
2284
2285 begin = base + data_tail % size;
2286 end = base + data_head % size;
2287
2288 while (begin != end) {
2289 struct perf_event_header *ehdr;
2290
2291 ehdr = begin;
2292 if (begin + ehdr->size > base + size) {
2293 long len = base + size - begin;
2294
2295 if (*buf_len < ehdr->size) {
2296 free(*buf);
2297 *buf = malloc(ehdr->size);
2298 if (!*buf) {
2299 ret = LIBBPF_PERF_EVENT_ERROR;
2300 break;
2301 }
2302 *buf_len = ehdr->size;
2303 }
2304
2305 memcpy(*buf, begin, len);
2306 memcpy(*buf + len, base, ehdr->size - len);
2307 ehdr = (void *)*buf;
2308 begin = base + ehdr->size - len;
2309 } else if (begin + ehdr->size == base + size) {
2310 begin = base;
2311 } else {
2312 begin += ehdr->size;
2313 }
2314
2315 ret = fn(ehdr, priv);
2316 if (ret != LIBBPF_PERF_EVENT_CONT)
2317 break;
2318
2319 data_tail += ehdr->size;
2320 }
2321
2322 __sync_synchronize();
2323 header->data_tail = data_tail;
2324
2325 return ret;
2326}
2327
