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perf test: Add libbpf relocation checker
[deliverable/linux.git] / tools / lib / bpf / libbpf.c
1 /*
2 * Common eBPF ELF object loading operations.
3 *
4 * Copyright (C) 2013-2015 Alexei Starovoitov <ast@kernel.org>
5 * Copyright (C) 2015 Wang Nan <wangnan0@huawei.com>
6 * Copyright (C) 2015 Huawei Inc.
7 */
8
9 #include <stdlib.h>
10 #include <stdio.h>
11 #include <stdarg.h>
12 #include <inttypes.h>
13 #include <string.h>
14 #include <unistd.h>
15 #include <fcntl.h>
16 #include <errno.h>
17 #include <asm/unistd.h>
18 #include <linux/kernel.h>
19 #include <linux/bpf.h>
20 #include <linux/list.h>
21 #include <libelf.h>
22 #include <gelf.h>
23
24 #include "libbpf.h"
25 #include "bpf.h"
26
27 #define __printf(a, b) __attribute__((format(printf, a, b)))
28
29 __printf(1, 2)
30 static int __base_pr(const char *format, ...)
31 {
32 va_list args;
33 int err;
34
35 va_start(args, format);
36 err = vfprintf(stderr, format, args);
37 va_end(args);
38 return err;
39 }
40
41 static __printf(1, 2) libbpf_print_fn_t __pr_warning = __base_pr;
42 static __printf(1, 2) libbpf_print_fn_t __pr_info = __base_pr;
43 static __printf(1, 2) libbpf_print_fn_t __pr_debug;
44
45 #define __pr(func, fmt, ...) \
46 do { \
47 if ((func)) \
48 (func)("libbpf: " fmt, ##__VA_ARGS__); \
49 } while (0)
50
51 #define pr_warning(fmt, ...) __pr(__pr_warning, fmt, ##__VA_ARGS__)
52 #define pr_info(fmt, ...) __pr(__pr_info, fmt, ##__VA_ARGS__)
53 #define pr_debug(fmt, ...) __pr(__pr_debug, fmt, ##__VA_ARGS__)
54
55 void libbpf_set_print(libbpf_print_fn_t warn,
56 libbpf_print_fn_t info,
57 libbpf_print_fn_t debug)
58 {
59 __pr_warning = warn;
60 __pr_info = info;
61 __pr_debug = debug;
62 }
63
64 #define STRERR_BUFSIZE 128
65
66 #define ERRNO_OFFSET(e) ((e) - __LIBBPF_ERRNO__START)
67 #define ERRCODE_OFFSET(c) ERRNO_OFFSET(LIBBPF_ERRNO__##c)
68 #define NR_ERRNO (__LIBBPF_ERRNO__END - __LIBBPF_ERRNO__START)
69
70 static const char *libbpf_strerror_table[NR_ERRNO] = {
71 [ERRCODE_OFFSET(LIBELF)] = "Something wrong in libelf",
72 [ERRCODE_OFFSET(FORMAT)] = "BPF object format invalid",
73 [ERRCODE_OFFSET(KVERSION)] = "'version' section incorrect or lost",
74 [ERRCODE_OFFSET(ENDIAN)] = "Endian missmatch",
75 [ERRCODE_OFFSET(INTERNAL)] = "Internal error in libbpf",
76 [ERRCODE_OFFSET(RELOC)] = "Relocation failed",
77 [ERRCODE_OFFSET(VERIFY)] = "Kernel verifier blocks program loading",
78 [ERRCODE_OFFSET(PROG2BIG)] = "Program too big",
79 [ERRCODE_OFFSET(KVER)] = "Incorrect kernel version",
80 };
81
82 int libbpf_strerror(int err, char *buf, size_t size)
83 {
84 if (!buf || !size)
85 return -1;
86
87 err = err > 0 ? err : -err;
88
89 if (err < __LIBBPF_ERRNO__START) {
90 int ret;
91
92 ret = strerror_r(err, buf, size);
93 buf[size - 1] = '\0';
94 return ret;
95 }
96
97 if (err < __LIBBPF_ERRNO__END) {
98 const char *msg;
99
100 msg = libbpf_strerror_table[ERRNO_OFFSET(err)];
101 snprintf(buf, size, "%s", msg);
102 buf[size - 1] = '\0';
103 return 0;
104 }
105
106 snprintf(buf, size, "Unknown libbpf error %d", err);
107 buf[size - 1] = '\0';
108 return -1;
109 }
110
111 #define CHECK_ERR(action, err, out) do { \
112 err = action; \
113 if (err) \
114 goto out; \
115 } while(0)
116
117
118 /* Copied from tools/perf/util/util.h */
119 #ifndef zfree
120 # define zfree(ptr) ({ free(*ptr); *ptr = NULL; })
121 #endif
122
123 #ifndef zclose
124 # define zclose(fd) ({ \
125 int ___err = 0; \
126 if ((fd) >= 0) \
127 ___err = close((fd)); \
128 fd = -1; \
129 ___err; })
130 #endif
131
132 #ifdef HAVE_LIBELF_MMAP_SUPPORT
133 # define LIBBPF_ELF_C_READ_MMAP ELF_C_READ_MMAP
134 #else
135 # define LIBBPF_ELF_C_READ_MMAP ELF_C_READ
136 #endif
137
138 /*
139 * bpf_prog should be a better name but it has been used in
140 * linux/filter.h.
141 */
142 struct bpf_program {
143 /* Index in elf obj file, for relocation use. */
144 int idx;
145 char *section_name;
146 struct bpf_insn *insns;
147 size_t insns_cnt;
148
149 struct {
150 int insn_idx;
151 int map_idx;
152 } *reloc_desc;
153 int nr_reloc;
154
155 struct {
156 int nr;
157 int *fds;
158 } instances;
159 bpf_program_prep_t preprocessor;
160
161 struct bpf_object *obj;
162 void *priv;
163 bpf_program_clear_priv_t clear_priv;
164 };
165
166 struct bpf_map {
167 int fd;
168 char *name;
169 struct bpf_map_def def;
170 void *priv;
171 bpf_map_clear_priv_t clear_priv;
172 };
173
174 static LIST_HEAD(bpf_objects_list);
175
176 struct bpf_object {
177 char license[64];
178 u32 kern_version;
179
180 struct bpf_program *programs;
181 size_t nr_programs;
182 struct bpf_map *maps;
183 size_t nr_maps;
184
185 bool loaded;
186
187 /*
188 * Information when doing elf related work. Only valid if fd
189 * is valid.
190 */
191 struct {
192 int fd;
193 void *obj_buf;
194 size_t obj_buf_sz;
195 Elf *elf;
196 GElf_Ehdr ehdr;
197 Elf_Data *symbols;
198 size_t strtabidx;
199 struct {
200 GElf_Shdr shdr;
201 Elf_Data *data;
202 } *reloc;
203 int nr_reloc;
204 } efile;
205 /*
206 * All loaded bpf_object is linked in a list, which is
207 * hidden to caller. bpf_objects__<func> handlers deal with
208 * all objects.
209 */
210 struct list_head list;
211 char path[];
212 };
213 #define obj_elf_valid(o) ((o)->efile.elf)
214
215 static void bpf_program__unload(struct bpf_program *prog)
216 {
217 int i;
218
219 if (!prog)
220 return;
221
222 /*
223 * If the object is opened but the program was never loaded,
224 * it is possible that prog->instances.nr == -1.
225 */
226 if (prog->instances.nr > 0) {
227 for (i = 0; i < prog->instances.nr; i++)
228 zclose(prog->instances.fds[i]);
229 } else if (prog->instances.nr != -1) {
230 pr_warning("Internal error: instances.nr is %d\n",
231 prog->instances.nr);
232 }
233
234 prog->instances.nr = -1;
235 zfree(&prog->instances.fds);
236 }
237
238 static void bpf_program__exit(struct bpf_program *prog)
239 {
240 if (!prog)
241 return;
242
243 if (prog->clear_priv)
244 prog->clear_priv(prog, prog->priv);
245
246 prog->priv = NULL;
247 prog->clear_priv = NULL;
248
249 bpf_program__unload(prog);
250 zfree(&prog->section_name);
251 zfree(&prog->insns);
252 zfree(&prog->reloc_desc);
253
254 prog->nr_reloc = 0;
255 prog->insns_cnt = 0;
256 prog->idx = -1;
257 }
258
259 static int
260 bpf_program__init(void *data, size_t size, char *name, int idx,
261 struct bpf_program *prog)
262 {
263 if (size < sizeof(struct bpf_insn)) {
264 pr_warning("corrupted section '%s'\n", name);
265 return -EINVAL;
266 }
267
268 bzero(prog, sizeof(*prog));
269
270 prog->section_name = strdup(name);
271 if (!prog->section_name) {
272 pr_warning("failed to alloc name for prog %s\n",
273 name);
274 goto errout;
275 }
276
277 prog->insns = malloc(size);
278 if (!prog->insns) {
279 pr_warning("failed to alloc insns for %s\n", name);
280 goto errout;
281 }
282 prog->insns_cnt = size / sizeof(struct bpf_insn);
283 memcpy(prog->insns, data,
284 prog->insns_cnt * sizeof(struct bpf_insn));
285 prog->idx = idx;
286 prog->instances.fds = NULL;
287 prog->instances.nr = -1;
288
289 return 0;
290 errout:
291 bpf_program__exit(prog);
292 return -ENOMEM;
293 }
294
295 static int
296 bpf_object__add_program(struct bpf_object *obj, void *data, size_t size,
297 char *name, int idx)
298 {
299 struct bpf_program prog, *progs;
300 int nr_progs, err;
301
302 err = bpf_program__init(data, size, name, idx, &prog);
303 if (err)
304 return err;
305
306 progs = obj->programs;
307 nr_progs = obj->nr_programs;
308
309 progs = realloc(progs, sizeof(progs[0]) * (nr_progs + 1));
310 if (!progs) {
311 /*
312 * In this case the original obj->programs
313 * is still valid, so don't need special treat for
314 * bpf_close_object().
315 */
316 pr_warning("failed to alloc a new program '%s'\n",
317 name);
318 bpf_program__exit(&prog);
319 return -ENOMEM;
320 }
321
322 pr_debug("found program %s\n", prog.section_name);
323 obj->programs = progs;
324 obj->nr_programs = nr_progs + 1;
325 prog.obj = obj;
326 progs[nr_progs] = prog;
327 return 0;
328 }
329
330 static struct bpf_object *bpf_object__new(const char *path,
331 void *obj_buf,
332 size_t obj_buf_sz)
333 {
334 struct bpf_object *obj;
335
336 obj = calloc(1, sizeof(struct bpf_object) + strlen(path) + 1);
337 if (!obj) {
338 pr_warning("alloc memory failed for %s\n", path);
339 return ERR_PTR(-ENOMEM);
340 }
341
342 strcpy(obj->path, path);
343 obj->efile.fd = -1;
344
345 /*
346 * Caller of this function should also calls
347 * bpf_object__elf_finish() after data collection to return
348 * obj_buf to user. If not, we should duplicate the buffer to
349 * avoid user freeing them before elf finish.
350 */
351 obj->efile.obj_buf = obj_buf;
352 obj->efile.obj_buf_sz = obj_buf_sz;
353
354 obj->loaded = false;
355
356 INIT_LIST_HEAD(&obj->list);
357 list_add(&obj->list, &bpf_objects_list);
358 return obj;
359 }
360
361 static void bpf_object__elf_finish(struct bpf_object *obj)
362 {
363 if (!obj_elf_valid(obj))
364 return;
365
366 if (obj->efile.elf) {
367 elf_end(obj->efile.elf);
368 obj->efile.elf = NULL;
369 }
370 obj->efile.symbols = NULL;
371
372 zfree(&obj->efile.reloc);
373 obj->efile.nr_reloc = 0;
374 zclose(obj->efile.fd);
375 obj->efile.obj_buf = NULL;
376 obj->efile.obj_buf_sz = 0;
377 }
378
379 static int bpf_object__elf_init(struct bpf_object *obj)
380 {
381 int err = 0;
382 GElf_Ehdr *ep;
383
384 if (obj_elf_valid(obj)) {
385 pr_warning("elf init: internal error\n");
386 return -LIBBPF_ERRNO__LIBELF;
387 }
388
389 if (obj->efile.obj_buf_sz > 0) {
390 /*
391 * obj_buf should have been validated by
392 * bpf_object__open_buffer().
393 */
394 obj->efile.elf = elf_memory(obj->efile.obj_buf,
395 obj->efile.obj_buf_sz);
396 } else {
397 obj->efile.fd = open(obj->path, O_RDONLY);
398 if (obj->efile.fd < 0) {
399 pr_warning("failed to open %s: %s\n", obj->path,
400 strerror(errno));
401 return -errno;
402 }
403
404 obj->efile.elf = elf_begin(obj->efile.fd,
405 LIBBPF_ELF_C_READ_MMAP,
406 NULL);
407 }
408
409 if (!obj->efile.elf) {
410 pr_warning("failed to open %s as ELF file\n",
411 obj->path);
412 err = -LIBBPF_ERRNO__LIBELF;
413 goto errout;
414 }
415
416 if (!gelf_getehdr(obj->efile.elf, &obj->efile.ehdr)) {
417 pr_warning("failed to get EHDR from %s\n",
418 obj->path);
419 err = -LIBBPF_ERRNO__FORMAT;
420 goto errout;
421 }
422 ep = &obj->efile.ehdr;
423
424 if ((ep->e_type != ET_REL) || (ep->e_machine != 0)) {
425 pr_warning("%s is not an eBPF object file\n",
426 obj->path);
427 err = -LIBBPF_ERRNO__FORMAT;
428 goto errout;
429 }
430
431 return 0;
432 errout:
433 bpf_object__elf_finish(obj);
434 return err;
435 }
436
437 static int
438 bpf_object__check_endianness(struct bpf_object *obj)
439 {
440 static unsigned int const endian = 1;
441
442 switch (obj->efile.ehdr.e_ident[EI_DATA]) {
443 case ELFDATA2LSB:
444 /* We are big endian, BPF obj is little endian. */
445 if (*(unsigned char const *)&endian != 1)
446 goto mismatch;
447 break;
448
449 case ELFDATA2MSB:
450 /* We are little endian, BPF obj is big endian. */
451 if (*(unsigned char const *)&endian != 0)
452 goto mismatch;
453 break;
454 default:
455 return -LIBBPF_ERRNO__ENDIAN;
456 }
457
458 return 0;
459
460 mismatch:
461 pr_warning("Error: endianness mismatch.\n");
462 return -LIBBPF_ERRNO__ENDIAN;
463 }
464
465 static int
466 bpf_object__init_license(struct bpf_object *obj,
467 void *data, size_t size)
468 {
469 memcpy(obj->license, data,
470 min(size, sizeof(obj->license) - 1));
471 pr_debug("license of %s is %s\n", obj->path, obj->license);
472 return 0;
473 }
474
475 static int
476 bpf_object__init_kversion(struct bpf_object *obj,
477 void *data, size_t size)
478 {
479 u32 kver;
480
481 if (size != sizeof(kver)) {
482 pr_warning("invalid kver section in %s\n", obj->path);
483 return -LIBBPF_ERRNO__FORMAT;
484 }
485 memcpy(&kver, data, sizeof(kver));
486 obj->kern_version = kver;
487 pr_debug("kernel version of %s is %x\n", obj->path,
488 obj->kern_version);
489 return 0;
490 }
491
492 static int
493 bpf_object__init_maps(struct bpf_object *obj, void *data,
494 size_t size)
495 {
496 size_t nr_maps;
497 int i;
498
499 nr_maps = size / sizeof(struct bpf_map_def);
500 if (!data || !nr_maps) {
501 pr_debug("%s doesn't need map definition\n",
502 obj->path);
503 return 0;
504 }
505
506 pr_debug("maps in %s: %zd bytes\n", obj->path, size);
507
508 obj->maps = calloc(nr_maps, sizeof(obj->maps[0]));
509 if (!obj->maps) {
510 pr_warning("alloc maps for object failed\n");
511 return -ENOMEM;
512 }
513 obj->nr_maps = nr_maps;
514
515 for (i = 0; i < nr_maps; i++) {
516 struct bpf_map_def *def = &obj->maps[i].def;
517
518 /*
519 * fill all fd with -1 so won't close incorrect
520 * fd (fd=0 is stdin) when failure (zclose won't close
521 * negative fd)).
522 */
523 obj->maps[i].fd = -1;
524
525 /* Save map definition into obj->maps */
526 *def = ((struct bpf_map_def *)data)[i];
527 }
528 return 0;
529 }
530
531 static int
532 bpf_object__init_maps_name(struct bpf_object *obj, int maps_shndx)
533 {
534 int i;
535 Elf_Data *symbols = obj->efile.symbols;
536
537 if (!symbols || maps_shndx < 0)
538 return -EINVAL;
539
540 for (i = 0; i < symbols->d_size / sizeof(GElf_Sym); i++) {
541 GElf_Sym sym;
542 size_t map_idx;
543 const char *map_name;
544
545 if (!gelf_getsym(symbols, i, &sym))
546 continue;
547 if (sym.st_shndx != maps_shndx)
548 continue;
549
550 map_name = elf_strptr(obj->efile.elf,
551 obj->efile.strtabidx,
552 sym.st_name);
553 map_idx = sym.st_value / sizeof(struct bpf_map_def);
554 if (map_idx >= obj->nr_maps) {
555 pr_warning("index of map \"%s\" is buggy: %zu > %zu\n",
556 map_name, map_idx, obj->nr_maps);
557 continue;
558 }
559 obj->maps[map_idx].name = strdup(map_name);
560 if (!obj->maps[map_idx].name) {
561 pr_warning("failed to alloc map name\n");
562 return -ENOMEM;
563 }
564 pr_debug("map %zu is \"%s\"\n", map_idx,
565 obj->maps[map_idx].name);
566 }
567 return 0;
568 }
569
570 static int bpf_object__elf_collect(struct bpf_object *obj)
571 {
572 Elf *elf = obj->efile.elf;
573 GElf_Ehdr *ep = &obj->efile.ehdr;
574 Elf_Scn *scn = NULL;
575 int idx = 0, err = 0, maps_shndx = -1;
576
577 /* Elf is corrupted/truncated, avoid calling elf_strptr. */
578 if (!elf_rawdata(elf_getscn(elf, ep->e_shstrndx), NULL)) {
579 pr_warning("failed to get e_shstrndx from %s\n",
580 obj->path);
581 return -LIBBPF_ERRNO__FORMAT;
582 }
583
584 while ((scn = elf_nextscn(elf, scn)) != NULL) {
585 char *name;
586 GElf_Shdr sh;
587 Elf_Data *data;
588
589 idx++;
590 if (gelf_getshdr(scn, &sh) != &sh) {
591 pr_warning("failed to get section header from %s\n",
592 obj->path);
593 err = -LIBBPF_ERRNO__FORMAT;
594 goto out;
595 }
596
597 name = elf_strptr(elf, ep->e_shstrndx, sh.sh_name);
598 if (!name) {
599 pr_warning("failed to get section name from %s\n",
600 obj->path);
601 err = -LIBBPF_ERRNO__FORMAT;
602 goto out;
603 }
604
605 data = elf_getdata(scn, 0);
606 if (!data) {
607 pr_warning("failed to get section data from %s(%s)\n",
608 name, obj->path);
609 err = -LIBBPF_ERRNO__FORMAT;
610 goto out;
611 }
612 pr_debug("section %s, size %ld, link %d, flags %lx, type=%d\n",
613 name, (unsigned long)data->d_size,
614 (int)sh.sh_link, (unsigned long)sh.sh_flags,
615 (int)sh.sh_type);
616
617 if (strcmp(name, "license") == 0)
618 err = bpf_object__init_license(obj,
619 data->d_buf,
620 data->d_size);
621 else if (strcmp(name, "version") == 0)
622 err = bpf_object__init_kversion(obj,
623 data->d_buf,
624 data->d_size);
625 else if (strcmp(name, "maps") == 0) {
626 err = bpf_object__init_maps(obj, data->d_buf,
627 data->d_size);
628 maps_shndx = idx;
629 } else if (sh.sh_type == SHT_SYMTAB) {
630 if (obj->efile.symbols) {
631 pr_warning("bpf: multiple SYMTAB in %s\n",
632 obj->path);
633 err = -LIBBPF_ERRNO__FORMAT;
634 } else {
635 obj->efile.symbols = data;
636 obj->efile.strtabidx = sh.sh_link;
637 }
638 } else if ((sh.sh_type == SHT_PROGBITS) &&
639 (sh.sh_flags & SHF_EXECINSTR) &&
640 (data->d_size > 0)) {
641 err = bpf_object__add_program(obj, data->d_buf,
642 data->d_size, name, idx);
643 if (err) {
644 char errmsg[STRERR_BUFSIZE];
645
646 strerror_r(-err, errmsg, sizeof(errmsg));
647 pr_warning("failed to alloc program %s (%s): %s",
648 name, obj->path, errmsg);
649 }
650 } else if (sh.sh_type == SHT_REL) {
651 void *reloc = obj->efile.reloc;
652 int nr_reloc = obj->efile.nr_reloc + 1;
653
654 reloc = realloc(reloc,
655 sizeof(*obj->efile.reloc) * nr_reloc);
656 if (!reloc) {
657 pr_warning("realloc failed\n");
658 err = -ENOMEM;
659 } else {
660 int n = nr_reloc - 1;
661
662 obj->efile.reloc = reloc;
663 obj->efile.nr_reloc = nr_reloc;
664
665 obj->efile.reloc[n].shdr = sh;
666 obj->efile.reloc[n].data = data;
667 }
668 }
669 if (err)
670 goto out;
671 }
672
673 if (!obj->efile.strtabidx || obj->efile.strtabidx >= idx) {
674 pr_warning("Corrupted ELF file: index of strtab invalid\n");
675 return LIBBPF_ERRNO__FORMAT;
676 }
677 if (maps_shndx >= 0)
678 err = bpf_object__init_maps_name(obj, maps_shndx);
679 out:
680 return err;
681 }
682
683 static struct bpf_program *
684 bpf_object__find_prog_by_idx(struct bpf_object *obj, int idx)
685 {
686 struct bpf_program *prog;
687 size_t i;
688
689 for (i = 0; i < obj->nr_programs; i++) {
690 prog = &obj->programs[i];
691 if (prog->idx == idx)
692 return prog;
693 }
694 return NULL;
695 }
696
697 static int
698 bpf_program__collect_reloc(struct bpf_program *prog,
699 size_t nr_maps, GElf_Shdr *shdr,
700 Elf_Data *data, Elf_Data *symbols)
701 {
702 int i, nrels;
703
704 pr_debug("collecting relocating info for: '%s'\n",
705 prog->section_name);
706 nrels = shdr->sh_size / shdr->sh_entsize;
707
708 prog->reloc_desc = malloc(sizeof(*prog->reloc_desc) * nrels);
709 if (!prog->reloc_desc) {
710 pr_warning("failed to alloc memory in relocation\n");
711 return -ENOMEM;
712 }
713 prog->nr_reloc = nrels;
714
715 for (i = 0; i < nrels; i++) {
716 GElf_Sym sym;
717 GElf_Rel rel;
718 unsigned int insn_idx;
719 struct bpf_insn *insns = prog->insns;
720 size_t map_idx;
721
722 if (!gelf_getrel(data, i, &rel)) {
723 pr_warning("relocation: failed to get %d reloc\n", i);
724 return -LIBBPF_ERRNO__FORMAT;
725 }
726
727 insn_idx = rel.r_offset / sizeof(struct bpf_insn);
728 pr_debug("relocation: insn_idx=%u\n", insn_idx);
729
730 if (!gelf_getsym(symbols,
731 GELF_R_SYM(rel.r_info),
732 &sym)) {
733 pr_warning("relocation: symbol %"PRIx64" not found\n",
734 GELF_R_SYM(rel.r_info));
735 return -LIBBPF_ERRNO__FORMAT;
736 }
737
738 if (insns[insn_idx].code != (BPF_LD | BPF_IMM | BPF_DW)) {
739 pr_warning("bpf: relocation: invalid relo for insns[%d].code 0x%x\n",
740 insn_idx, insns[insn_idx].code);
741 return -LIBBPF_ERRNO__RELOC;
742 }
743
744 map_idx = sym.st_value / sizeof(struct bpf_map_def);
745 if (map_idx >= nr_maps) {
746 pr_warning("bpf relocation: map_idx %d large than %d\n",
747 (int)map_idx, (int)nr_maps - 1);
748 return -LIBBPF_ERRNO__RELOC;
749 }
750
751 prog->reloc_desc[i].insn_idx = insn_idx;
752 prog->reloc_desc[i].map_idx = map_idx;
753 }
754 return 0;
755 }
756
757 static int
758 bpf_object__create_maps(struct bpf_object *obj)
759 {
760 unsigned int i;
761
762 for (i = 0; i < obj->nr_maps; i++) {
763 struct bpf_map_def *def = &obj->maps[i].def;
764 int *pfd = &obj->maps[i].fd;
765
766 *pfd = bpf_create_map(def->type,
767 def->key_size,
768 def->value_size,
769 def->max_entries);
770 if (*pfd < 0) {
771 size_t j;
772 int err = *pfd;
773
774 pr_warning("failed to create map: %s\n",
775 strerror(errno));
776 for (j = 0; j < i; j++)
777 zclose(obj->maps[j].fd);
778 return err;
779 }
780 pr_debug("create map: fd=%d\n", *pfd);
781 }
782
783 return 0;
784 }
785
786 static int
787 bpf_program__relocate(struct bpf_program *prog, struct bpf_object *obj)
788 {
789 int i;
790
791 if (!prog || !prog->reloc_desc)
792 return 0;
793
794 for (i = 0; i < prog->nr_reloc; i++) {
795 int insn_idx, map_idx;
796 struct bpf_insn *insns = prog->insns;
797
798 insn_idx = prog->reloc_desc[i].insn_idx;
799 map_idx = prog->reloc_desc[i].map_idx;
800
801 if (insn_idx >= (int)prog->insns_cnt) {
802 pr_warning("relocation out of range: '%s'\n",
803 prog->section_name);
804 return -LIBBPF_ERRNO__RELOC;
805 }
806 insns[insn_idx].src_reg = BPF_PSEUDO_MAP_FD;
807 insns[insn_idx].imm = obj->maps[map_idx].fd;
808 }
809
810 zfree(&prog->reloc_desc);
811 prog->nr_reloc = 0;
812 return 0;
813 }
814
815
816 static int
817 bpf_object__relocate(struct bpf_object *obj)
818 {
819 struct bpf_program *prog;
820 size_t i;
821 int err;
822
823 for (i = 0; i < obj->nr_programs; i++) {
824 prog = &obj->programs[i];
825
826 err = bpf_program__relocate(prog, obj);
827 if (err) {
828 pr_warning("failed to relocate '%s'\n",
829 prog->section_name);
830 return err;
831 }
832 }
833 return 0;
834 }
835
836 static int bpf_object__collect_reloc(struct bpf_object *obj)
837 {
838 int i, err;
839
840 if (!obj_elf_valid(obj)) {
841 pr_warning("Internal error: elf object is closed\n");
842 return -LIBBPF_ERRNO__INTERNAL;
843 }
844
845 for (i = 0; i < obj->efile.nr_reloc; i++) {
846 GElf_Shdr *shdr = &obj->efile.reloc[i].shdr;
847 Elf_Data *data = obj->efile.reloc[i].data;
848 int idx = shdr->sh_info;
849 struct bpf_program *prog;
850 size_t nr_maps = obj->nr_maps;
851
852 if (shdr->sh_type != SHT_REL) {
853 pr_warning("internal error at %d\n", __LINE__);
854 return -LIBBPF_ERRNO__INTERNAL;
855 }
856
857 prog = bpf_object__find_prog_by_idx(obj, idx);
858 if (!prog) {
859 pr_warning("relocation failed: no %d section\n",
860 idx);
861 return -LIBBPF_ERRNO__RELOC;
862 }
863
864 err = bpf_program__collect_reloc(prog, nr_maps,
865 shdr, data,
866 obj->efile.symbols);
867 if (err)
868 return err;
869 }
870 return 0;
871 }
872
873 static int
874 load_program(struct bpf_insn *insns, int insns_cnt,
875 char *license, u32 kern_version, int *pfd)
876 {
877 int ret;
878 char *log_buf;
879
880 if (!insns || !insns_cnt)
881 return -EINVAL;
882
883 log_buf = malloc(BPF_LOG_BUF_SIZE);
884 if (!log_buf)
885 pr_warning("Alloc log buffer for bpf loader error, continue without log\n");
886
887 ret = bpf_load_program(BPF_PROG_TYPE_KPROBE, insns,
888 insns_cnt, license, kern_version,
889 log_buf, BPF_LOG_BUF_SIZE);
890
891 if (ret >= 0) {
892 *pfd = ret;
893 ret = 0;
894 goto out;
895 }
896
897 ret = -LIBBPF_ERRNO__LOAD;
898 pr_warning("load bpf program failed: %s\n", strerror(errno));
899
900 if (log_buf && log_buf[0] != '\0') {
901 ret = -LIBBPF_ERRNO__VERIFY;
902 pr_warning("-- BEGIN DUMP LOG ---\n");
903 pr_warning("\n%s\n", log_buf);
904 pr_warning("-- END LOG --\n");
905 } else {
906 if (insns_cnt >= BPF_MAXINSNS) {
907 pr_warning("Program too large (%d insns), at most %d insns\n",
908 insns_cnt, BPF_MAXINSNS);
909 ret = -LIBBPF_ERRNO__PROG2BIG;
910 } else if (log_buf) {
911 pr_warning("log buffer is empty\n");
912 ret = -LIBBPF_ERRNO__KVER;
913 }
914 }
915
916 out:
917 free(log_buf);
918 return ret;
919 }
920
921 static int
922 bpf_program__load(struct bpf_program *prog,
923 char *license, u32 kern_version)
924 {
925 int err = 0, fd, i;
926
927 if (prog->instances.nr < 0 || !prog->instances.fds) {
928 if (prog->preprocessor) {
929 pr_warning("Internal error: can't load program '%s'\n",
930 prog->section_name);
931 return -LIBBPF_ERRNO__INTERNAL;
932 }
933
934 prog->instances.fds = malloc(sizeof(int));
935 if (!prog->instances.fds) {
936 pr_warning("Not enough memory for BPF fds\n");
937 return -ENOMEM;
938 }
939 prog->instances.nr = 1;
940 prog->instances.fds[0] = -1;
941 }
942
943 if (!prog->preprocessor) {
944 if (prog->instances.nr != 1) {
945 pr_warning("Program '%s' is inconsistent: nr(%d) != 1\n",
946 prog->section_name, prog->instances.nr);
947 }
948 err = load_program(prog->insns, prog->insns_cnt,
949 license, kern_version, &fd);
950 if (!err)
951 prog->instances.fds[0] = fd;
952 goto out;
953 }
954
955 for (i = 0; i < prog->instances.nr; i++) {
956 struct bpf_prog_prep_result result;
957 bpf_program_prep_t preprocessor = prog->preprocessor;
958
959 bzero(&result, sizeof(result));
960 err = preprocessor(prog, i, prog->insns,
961 prog->insns_cnt, &result);
962 if (err) {
963 pr_warning("Preprocessing the %dth instance of program '%s' failed\n",
964 i, prog->section_name);
965 goto out;
966 }
967
968 if (!result.new_insn_ptr || !result.new_insn_cnt) {
969 pr_debug("Skip loading the %dth instance of program '%s'\n",
970 i, prog->section_name);
971 prog->instances.fds[i] = -1;
972 if (result.pfd)
973 *result.pfd = -1;
974 continue;
975 }
976
977 err = load_program(result.new_insn_ptr,
978 result.new_insn_cnt,
979 license, kern_version, &fd);
980
981 if (err) {
982 pr_warning("Loading the %dth instance of program '%s' failed\n",
983 i, prog->section_name);
984 goto out;
985 }
986
987 if (result.pfd)
988 *result.pfd = fd;
989 prog->instances.fds[i] = fd;
990 }
991 out:
992 if (err)
993 pr_warning("failed to load program '%s'\n",
994 prog->section_name);
995 zfree(&prog->insns);
996 prog->insns_cnt = 0;
997 return err;
998 }
999
1000 static int
1001 bpf_object__load_progs(struct bpf_object *obj)
1002 {
1003 size_t i;
1004 int err;
1005
1006 for (i = 0; i < obj->nr_programs; i++) {
1007 err = bpf_program__load(&obj->programs[i],
1008 obj->license,
1009 obj->kern_version);
1010 if (err)
1011 return err;
1012 }
1013 return 0;
1014 }
1015
1016 static int bpf_object__validate(struct bpf_object *obj)
1017 {
1018 if (obj->kern_version == 0) {
1019 pr_warning("%s doesn't provide kernel version\n",
1020 obj->path);
1021 return -LIBBPF_ERRNO__KVERSION;
1022 }
1023 return 0;
1024 }
1025
1026 static struct bpf_object *
1027 __bpf_object__open(const char *path, void *obj_buf, size_t obj_buf_sz)
1028 {
1029 struct bpf_object *obj;
1030 int err;
1031
1032 if (elf_version(EV_CURRENT) == EV_NONE) {
1033 pr_warning("failed to init libelf for %s\n", path);
1034 return ERR_PTR(-LIBBPF_ERRNO__LIBELF);
1035 }
1036
1037 obj = bpf_object__new(path, obj_buf, obj_buf_sz);
1038 if (IS_ERR(obj))
1039 return obj;
1040
1041 CHECK_ERR(bpf_object__elf_init(obj), err, out);
1042 CHECK_ERR(bpf_object__check_endianness(obj), err, out);
1043 CHECK_ERR(bpf_object__elf_collect(obj), err, out);
1044 CHECK_ERR(bpf_object__collect_reloc(obj), err, out);
1045 CHECK_ERR(bpf_object__validate(obj), err, out);
1046
1047 bpf_object__elf_finish(obj);
1048 return obj;
1049 out:
1050 bpf_object__close(obj);
1051 return ERR_PTR(err);
1052 }
1053
1054 struct bpf_object *bpf_object__open(const char *path)
1055 {
1056 /* param validation */
1057 if (!path)
1058 return NULL;
1059
1060 pr_debug("loading %s\n", path);
1061
1062 return __bpf_object__open(path, NULL, 0);
1063 }
1064
1065 struct bpf_object *bpf_object__open_buffer(void *obj_buf,
1066 size_t obj_buf_sz,
1067 const char *name)
1068 {
1069 char tmp_name[64];
1070
1071 /* param validation */
1072 if (!obj_buf || obj_buf_sz <= 0)
1073 return NULL;
1074
1075 if (!name) {
1076 snprintf(tmp_name, sizeof(tmp_name), "%lx-%lx",
1077 (unsigned long)obj_buf,
1078 (unsigned long)obj_buf_sz);
1079 tmp_name[sizeof(tmp_name) - 1] = '\0';
1080 name = tmp_name;
1081 }
1082 pr_debug("loading object '%s' from buffer\n",
1083 name);
1084
1085 return __bpf_object__open(name, obj_buf, obj_buf_sz);
1086 }
1087
1088 int bpf_object__unload(struct bpf_object *obj)
1089 {
1090 size_t i;
1091
1092 if (!obj)
1093 return -EINVAL;
1094
1095 for (i = 0; i < obj->nr_maps; i++)
1096 zclose(obj->maps[i].fd);
1097
1098 for (i = 0; i < obj->nr_programs; i++)
1099 bpf_program__unload(&obj->programs[i]);
1100
1101 return 0;
1102 }
1103
1104 int bpf_object__load(struct bpf_object *obj)
1105 {
1106 int err;
1107
1108 if (!obj)
1109 return -EINVAL;
1110
1111 if (obj->loaded) {
1112 pr_warning("object should not be loaded twice\n");
1113 return -EINVAL;
1114 }
1115
1116 obj->loaded = true;
1117
1118 CHECK_ERR(bpf_object__create_maps(obj), err, out);
1119 CHECK_ERR(bpf_object__relocate(obj), err, out);
1120 CHECK_ERR(bpf_object__load_progs(obj), err, out);
1121
1122 return 0;
1123 out:
1124 bpf_object__unload(obj);
1125 pr_warning("failed to load object '%s'\n", obj->path);
1126 return err;
1127 }
1128
1129 void bpf_object__close(struct bpf_object *obj)
1130 {
1131 size_t i;
1132
1133 if (!obj)
1134 return;
1135
1136 bpf_object__elf_finish(obj);
1137 bpf_object__unload(obj);
1138
1139 for (i = 0; i < obj->nr_maps; i++) {
1140 zfree(&obj->maps[i].name);
1141 if (obj->maps[i].clear_priv)
1142 obj->maps[i].clear_priv(&obj->maps[i],
1143 obj->maps[i].priv);
1144 obj->maps[i].priv = NULL;
1145 obj->maps[i].clear_priv = NULL;
1146 }
1147 zfree(&obj->maps);
1148 obj->nr_maps = 0;
1149
1150 if (obj->programs && obj->nr_programs) {
1151 for (i = 0; i < obj->nr_programs; i++)
1152 bpf_program__exit(&obj->programs[i]);
1153 }
1154 zfree(&obj->programs);
1155
1156 list_del(&obj->list);
1157 free(obj);
1158 }
1159
1160 struct bpf_object *
1161 bpf_object__next(struct bpf_object *prev)
1162 {
1163 struct bpf_object *next;
1164
1165 if (!prev)
1166 next = list_first_entry(&bpf_objects_list,
1167 struct bpf_object,
1168 list);
1169 else
1170 next = list_next_entry(prev, list);
1171
1172 /* Empty list is noticed here so don't need checking on entry. */
1173 if (&next->list == &bpf_objects_list)
1174 return NULL;
1175
1176 return next;
1177 }
1178
1179 const char *
1180 bpf_object__get_name(struct bpf_object *obj)
1181 {
1182 if (!obj)
1183 return ERR_PTR(-EINVAL);
1184 return obj->path;
1185 }
1186
1187 unsigned int
1188 bpf_object__get_kversion(struct bpf_object *obj)
1189 {
1190 if (!obj)
1191 return 0;
1192 return obj->kern_version;
1193 }
1194
1195 struct bpf_program *
1196 bpf_program__next(struct bpf_program *prev, struct bpf_object *obj)
1197 {
1198 size_t idx;
1199
1200 if (!obj->programs)
1201 return NULL;
1202 /* First handler */
1203 if (prev == NULL)
1204 return &obj->programs[0];
1205
1206 if (prev->obj != obj) {
1207 pr_warning("error: program handler doesn't match object\n");
1208 return NULL;
1209 }
1210
1211 idx = (prev - obj->programs) + 1;
1212 if (idx >= obj->nr_programs)
1213 return NULL;
1214 return &obj->programs[idx];
1215 }
1216
1217 int bpf_program__set_private(struct bpf_program *prog,
1218 void *priv,
1219 bpf_program_clear_priv_t clear_priv)
1220 {
1221 if (prog->priv && prog->clear_priv)
1222 prog->clear_priv(prog, prog->priv);
1223
1224 prog->priv = priv;
1225 prog->clear_priv = clear_priv;
1226 return 0;
1227 }
1228
1229 int bpf_program__get_private(struct bpf_program *prog, void **ppriv)
1230 {
1231 *ppriv = prog->priv;
1232 return 0;
1233 }
1234
1235 const char *bpf_program__title(struct bpf_program *prog, bool needs_copy)
1236 {
1237 const char *title;
1238
1239 title = prog->section_name;
1240 if (needs_copy) {
1241 title = strdup(title);
1242 if (!title) {
1243 pr_warning("failed to strdup program title\n");
1244 return ERR_PTR(-ENOMEM);
1245 }
1246 }
1247
1248 return title;
1249 }
1250
1251 int bpf_program__fd(struct bpf_program *prog)
1252 {
1253 return bpf_program__nth_fd(prog, 0);
1254 }
1255
1256 int bpf_program__set_prep(struct bpf_program *prog, int nr_instances,
1257 bpf_program_prep_t prep)
1258 {
1259 int *instances_fds;
1260
1261 if (nr_instances <= 0 || !prep)
1262 return -EINVAL;
1263
1264 if (prog->instances.nr > 0 || prog->instances.fds) {
1265 pr_warning("Can't set pre-processor after loading\n");
1266 return -EINVAL;
1267 }
1268
1269 instances_fds = malloc(sizeof(int) * nr_instances);
1270 if (!instances_fds) {
1271 pr_warning("alloc memory failed for fds\n");
1272 return -ENOMEM;
1273 }
1274
1275 /* fill all fd with -1 */
1276 memset(instances_fds, -1, sizeof(int) * nr_instances);
1277
1278 prog->instances.nr = nr_instances;
1279 prog->instances.fds = instances_fds;
1280 prog->preprocessor = prep;
1281 return 0;
1282 }
1283
1284 int bpf_program__nth_fd(struct bpf_program *prog, int n)
1285 {
1286 int fd;
1287
1288 if (n >= prog->instances.nr || n < 0) {
1289 pr_warning("Can't get the %dth fd from program %s: only %d instances\n",
1290 n, prog->section_name, prog->instances.nr);
1291 return -EINVAL;
1292 }
1293
1294 fd = prog->instances.fds[n];
1295 if (fd < 0) {
1296 pr_warning("%dth instance of program '%s' is invalid\n",
1297 n, prog->section_name);
1298 return -ENOENT;
1299 }
1300
1301 return fd;
1302 }
1303
1304 int bpf_map__get_fd(struct bpf_map *map)
1305 {
1306 if (!map)
1307 return -EINVAL;
1308
1309 return map->fd;
1310 }
1311
1312 int bpf_map__get_def(struct bpf_map *map, struct bpf_map_def *pdef)
1313 {
1314 if (!map || !pdef)
1315 return -EINVAL;
1316
1317 *pdef = map->def;
1318 return 0;
1319 }
1320
1321 const char *bpf_map__get_name(struct bpf_map *map)
1322 {
1323 if (!map)
1324 return NULL;
1325 return map->name;
1326 }
1327
1328 int bpf_map__set_private(struct bpf_map *map, void *priv,
1329 bpf_map_clear_priv_t clear_priv)
1330 {
1331 if (!map)
1332 return -EINVAL;
1333
1334 if (map->priv) {
1335 if (map->clear_priv)
1336 map->clear_priv(map, map->priv);
1337 }
1338
1339 map->priv = priv;
1340 map->clear_priv = clear_priv;
1341 return 0;
1342 }
1343
1344 int bpf_map__get_private(struct bpf_map *map, void **ppriv)
1345 {
1346 if (!map)
1347 return -EINVAL;
1348
1349 if (ppriv)
1350 *ppriv = map->priv;
1351 return 0;
1352 }
1353
1354 struct bpf_map *
1355 bpf_map__next(struct bpf_map *prev, struct bpf_object *obj)
1356 {
1357 size_t idx;
1358 struct bpf_map *s, *e;
1359
1360 if (!obj || !obj->maps)
1361 return NULL;
1362
1363 s = obj->maps;
1364 e = obj->maps + obj->nr_maps;
1365
1366 if (prev == NULL)
1367 return s;
1368
1369 if ((prev < s) || (prev >= e)) {
1370 pr_warning("error in %s: map handler doesn't belong to object\n",
1371 __func__);
1372 return NULL;
1373 }
1374
1375 idx = (prev - obj->maps) + 1;
1376 if (idx >= obj->nr_maps)
1377 return NULL;
1378 return &obj->maps[idx];
1379 }
1380
1381 struct bpf_map *
1382 bpf_object__get_map_by_name(struct bpf_object *obj, const char *name)
1383 {
1384 struct bpf_map *pos;
1385
1386 bpf_map__for_each(pos, obj) {
1387 if (pos->name && !strcmp(pos->name, name))
1388 return pos;
1389 }
1390 return NULL;
1391 }
Linux kernel - Deliverables
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