1 /* 2 * Common eBPF ELF object loading operations. 3 * 4 * Copyright (C) 2013-2015 Alexei Starovoitov <ast@kernel.org> 5 * Copyright (C) 2015 Wang Nan <wangnan0@huawei.com> 6 * Copyright (C) 2015 Huawei Inc. 7 * Copyright (C) 2017 Nicira, Inc. 8 * 9 * This program is free software; you can redistribute it and/or 10 * modify it under the terms of the GNU Lesser General Public 11 * License as published by the Free Software Foundation; 12 * version 2.1 of the License (not later!) 13 * 14 * This program is distributed in the hope that it will be useful, 15 * but WITHOUT ANY WARRANTY; without even the implied warranty of 16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 17 * GNU Lesser General Public License for more details. 18 * 19 * You should have received a copy of the GNU Lesser General Public 20 * License along with this program; if not, see <http://www.gnu.org/licenses> 21 */ 22 23 #include <stdlib.h> 24 #include <stdio.h> 25 #include <stdarg.h> 26 #include <libgen.h> 27 #include <inttypes.h> 28 #include <string.h> 29 #include <unistd.h> 30 #include <fcntl.h> 31 #include <errno.h> 32 #include <asm/unistd.h> 33 #include <linux/err.h> 34 #include <linux/kernel.h> 35 #include <linux/bpf.h> 36 #include <linux/list.h> 37 #include <linux/limits.h> 38 #include <sys/stat.h> 39 #include <sys/types.h> 40 #include <sys/vfs.h> 41 #include <libelf.h> 42 #include <gelf.h> 43 44 #include "libbpf.h" 45 #include "bpf.h" 46 47 #ifndef EM_BPF 48 #define EM_BPF 247 49 #endif 50 51 #ifndef BPF_FS_MAGIC 52 #define BPF_FS_MAGIC 0xcafe4a11 53 #endif 54 55 #define __printf(a, b) __attribute__((format(printf, a, b))) 56 57 __printf(1, 2) 58 static int __base_pr(const char *format, ...) 59 { 60 va_list args; 61 int err; 62 63 va_start(args, format); 64 err = vfprintf(stderr, format, args); 65 va_end(args); 66 return err; 67 } 68 69 static __printf(1, 2) libbpf_print_fn_t __pr_warning = __base_pr; 70 static __printf(1, 2) libbpf_print_fn_t __pr_info = __base_pr; 71 static __printf(1, 2) libbpf_print_fn_t __pr_debug; 72 73 #define __pr(func, fmt, ...) \ 74 do { \ 75 if ((func)) \ 76 (func)("libbpf: " fmt, ##__VA_ARGS__); \ 77 } while (0) 78 79 #define pr_warning(fmt, ...) __pr(__pr_warning, fmt, ##__VA_ARGS__) 80 #define pr_info(fmt, ...) __pr(__pr_info, fmt, ##__VA_ARGS__) 81 #define pr_debug(fmt, ...) __pr(__pr_debug, fmt, ##__VA_ARGS__) 82 83 void libbpf_set_print(libbpf_print_fn_t warn, 84 libbpf_print_fn_t info, 85 libbpf_print_fn_t debug) 86 { 87 __pr_warning = warn; 88 __pr_info = info; 89 __pr_debug = debug; 90 } 91 92 #define STRERR_BUFSIZE 128 93 94 #define ERRNO_OFFSET(e) ((e) - __LIBBPF_ERRNO__START) 95 #define ERRCODE_OFFSET(c) ERRNO_OFFSET(LIBBPF_ERRNO__##c) 96 #define NR_ERRNO (__LIBBPF_ERRNO__END - __LIBBPF_ERRNO__START) 97 98 static const char *libbpf_strerror_table[NR_ERRNO] = { 99 [ERRCODE_OFFSET(LIBELF)] = "Something wrong in libelf", 100 [ERRCODE_OFFSET(FORMAT)] = "BPF object format invalid", 101 [ERRCODE_OFFSET(KVERSION)] = "'version' section incorrect or lost", 102 [ERRCODE_OFFSET(ENDIAN)] = "Endian mismatch", 103 [ERRCODE_OFFSET(INTERNAL)] = "Internal error in libbpf", 104 [ERRCODE_OFFSET(RELOC)] = "Relocation failed", 105 [ERRCODE_OFFSET(VERIFY)] = "Kernel verifier blocks program loading", 106 [ERRCODE_OFFSET(PROG2BIG)] = "Program too big", 107 [ERRCODE_OFFSET(KVER)] = "Incorrect kernel version", 108 [ERRCODE_OFFSET(PROGTYPE)] = "Kernel doesn't support this program type", 109 }; 110 111 int libbpf_strerror(int err, char *buf, size_t size) 112 { 113 if (!buf || !size) 114 return -1; 115 116 err = err > 0 ? err : -err; 117 118 if (err < __LIBBPF_ERRNO__START) { 119 int ret; 120 121 ret = strerror_r(err, buf, size); 122 buf[size - 1] = '\0'; 123 return ret; 124 } 125 126 if (err < __LIBBPF_ERRNO__END) { 127 const char *msg; 128 129 msg = libbpf_strerror_table[ERRNO_OFFSET(err)]; 130 snprintf(buf, size, "%s", msg); 131 buf[size - 1] = '\0'; 132 return 0; 133 } 134 135 snprintf(buf, size, "Unknown libbpf error %d", err); 136 buf[size - 1] = '\0'; 137 return -1; 138 } 139 140 #define CHECK_ERR(action, err, out) do { \ 141 err = action; \ 142 if (err) \ 143 goto out; \ 144 } while(0) 145 146 147 /* Copied from tools/perf/util/util.h */ 148 #ifndef zfree 149 # define zfree(ptr) ({ free(*ptr); *ptr = NULL; }) 150 #endif 151 152 #ifndef zclose 153 # define zclose(fd) ({ \ 154 int ___err = 0; \ 155 if ((fd) >= 0) \ 156 ___err = close((fd)); \ 157 fd = -1; \ 158 ___err; }) 159 #endif 160 161 #ifdef HAVE_LIBELF_MMAP_SUPPORT 162 # define LIBBPF_ELF_C_READ_MMAP ELF_C_READ_MMAP 163 #else 164 # define LIBBPF_ELF_C_READ_MMAP ELF_C_READ 165 #endif 166 167 /* 168 * bpf_prog should be a better name but it has been used in 169 * linux/filter.h. 170 */ 171 struct bpf_program { 172 /* Index in elf obj file, for relocation use. */ 173 int idx; 174 char *section_name; 175 struct bpf_insn *insns; 176 size_t insns_cnt; 177 enum bpf_prog_type type; 178 179 struct { 180 int insn_idx; 181 int map_idx; 182 } *reloc_desc; 183 int nr_reloc; 184 185 struct { 186 int nr; 187 int *fds; 188 } instances; 189 bpf_program_prep_t preprocessor; 190 191 struct bpf_object *obj; 192 void *priv; 193 bpf_program_clear_priv_t clear_priv; 194 }; 195 196 struct bpf_map { 197 int fd; 198 char *name; 199 size_t offset; 200 struct bpf_map_def def; 201 void *priv; 202 bpf_map_clear_priv_t clear_priv; 203 }; 204 205 static LIST_HEAD(bpf_objects_list); 206 207 struct bpf_object { 208 char license[64]; 209 u32 kern_version; 210 211 struct bpf_program *programs; 212 size_t nr_programs; 213 struct bpf_map *maps; 214 size_t nr_maps; 215 216 bool loaded; 217 218 /* 219 * Information when doing elf related work. Only valid if fd 220 * is valid. 221 */ 222 struct { 223 int fd; 224 void *obj_buf; 225 size_t obj_buf_sz; 226 Elf *elf; 227 GElf_Ehdr ehdr; 228 Elf_Data *symbols; 229 size_t strtabidx; 230 struct { 231 GElf_Shdr shdr; 232 Elf_Data *data; 233 } *reloc; 234 int nr_reloc; 235 int maps_shndx; 236 } efile; 237 /* 238 * All loaded bpf_object is linked in a list, which is 239 * hidden to caller. bpf_objects__<func> handlers deal with 240 * all objects. 241 */ 242 struct list_head list; 243 244 void *priv; 245 bpf_object_clear_priv_t clear_priv; 246 247 char path[]; 248 }; 249 #define obj_elf_valid(o) ((o)->efile.elf) 250 251 static void bpf_program__unload(struct bpf_program *prog) 252 { 253 int i; 254 255 if (!prog) 256 return; 257 258 /* 259 * If the object is opened but the program was never loaded, 260 * it is possible that prog->instances.nr == -1. 261 */ 262 if (prog->instances.nr > 0) { 263 for (i = 0; i < prog->instances.nr; i++) 264 zclose(prog->instances.fds[i]); 265 } else if (prog->instances.nr != -1) { 266 pr_warning("Internal error: instances.nr is %d\n", 267 prog->instances.nr); 268 } 269 270 prog->instances.nr = -1; 271 zfree(&prog->instances.fds); 272 } 273 274 static void bpf_program__exit(struct bpf_program *prog) 275 { 276 if (!prog) 277 return; 278 279 if (prog->clear_priv) 280 prog->clear_priv(prog, prog->priv); 281 282 prog->priv = NULL; 283 prog->clear_priv = NULL; 284 285 bpf_program__unload(prog); 286 zfree(&prog->section_name); 287 zfree(&prog->insns); 288 zfree(&prog->reloc_desc); 289 290 prog->nr_reloc = 0; 291 prog->insns_cnt = 0; 292 prog->idx = -1; 293 } 294 295 static int 296 bpf_program__init(void *data, size_t size, char *name, int idx, 297 struct bpf_program *prog) 298 { 299 if (size < sizeof(struct bpf_insn)) { 300 pr_warning("corrupted section '%s'\n", name); 301 return -EINVAL; 302 } 303 304 bzero(prog, sizeof(*prog)); 305 306 prog->section_name = strdup(name); 307 if (!prog->section_name) { 308 pr_warning("failed to alloc name for prog %s\n", 309 name); 310 goto errout; 311 } 312 313 prog->insns = malloc(size); 314 if (!prog->insns) { 315 pr_warning("failed to alloc insns for %s\n", name); 316 goto errout; 317 } 318 prog->insns_cnt = size / sizeof(struct bpf_insn); 319 memcpy(prog->insns, data, 320 prog->insns_cnt * sizeof(struct bpf_insn)); 321 prog->idx = idx; 322 prog->instances.fds = NULL; 323 prog->instances.nr = -1; 324 prog->type = BPF_PROG_TYPE_KPROBE; 325 326 return 0; 327 errout: 328 bpf_program__exit(prog); 329 return -ENOMEM; 330 } 331 332 static int 333 bpf_object__add_program(struct bpf_object *obj, void *data, size_t size, 334 char *name, int idx) 335 { 336 struct bpf_program prog, *progs; 337 int nr_progs, err; 338 339 err = bpf_program__init(data, size, name, idx, &prog); 340 if (err) 341 return err; 342 343 progs = obj->programs; 344 nr_progs = obj->nr_programs; 345 346 progs = realloc(progs, sizeof(progs[0]) * (nr_progs + 1)); 347 if (!progs) { 348 /* 349 * In this case the original obj->programs 350 * is still valid, so don't need special treat for 351 * bpf_close_object(). 352 */ 353 pr_warning("failed to alloc a new program '%s'\n", 354 name); 355 bpf_program__exit(&prog); 356 return -ENOMEM; 357 } 358 359 pr_debug("found program %s\n", prog.section_name); 360 obj->programs = progs; 361 obj->nr_programs = nr_progs + 1; 362 prog.obj = obj; 363 progs[nr_progs] = prog; 364 return 0; 365 } 366 367 static struct bpf_object *bpf_object__new(const char *path, 368 void *obj_buf, 369 size_t obj_buf_sz) 370 { 371 struct bpf_object *obj; 372 373 obj = calloc(1, sizeof(struct bpf_object) + strlen(path) + 1); 374 if (!obj) { 375 pr_warning("alloc memory failed for %s\n", path); 376 return ERR_PTR(-ENOMEM); 377 } 378 379 strcpy(obj->path, path); 380 obj->efile.fd = -1; 381 382 /* 383 * Caller of this function should also calls 384 * bpf_object__elf_finish() after data collection to return 385 * obj_buf to user. If not, we should duplicate the buffer to 386 * avoid user freeing them before elf finish. 387 */ 388 obj->efile.obj_buf = obj_buf; 389 obj->efile.obj_buf_sz = obj_buf_sz; 390 obj->efile.maps_shndx = -1; 391 392 obj->loaded = false; 393 394 INIT_LIST_HEAD(&obj->list); 395 list_add(&obj->list, &bpf_objects_list); 396 return obj; 397 } 398 399 static void bpf_object__elf_finish(struct bpf_object *obj) 400 { 401 if (!obj_elf_valid(obj)) 402 return; 403 404 if (obj->efile.elf) { 405 elf_end(obj->efile.elf); 406 obj->efile.elf = NULL; 407 } 408 obj->efile.symbols = NULL; 409 410 zfree(&obj->efile.reloc); 411 obj->efile.nr_reloc = 0; 412 zclose(obj->efile.fd); 413 obj->efile.obj_buf = NULL; 414 obj->efile.obj_buf_sz = 0; 415 } 416 417 static int bpf_object__elf_init(struct bpf_object *obj) 418 { 419 int err = 0; 420 GElf_Ehdr *ep; 421 422 if (obj_elf_valid(obj)) { 423 pr_warning("elf init: internal error\n"); 424 return -LIBBPF_ERRNO__LIBELF; 425 } 426 427 if (obj->efile.obj_buf_sz > 0) { 428 /* 429 * obj_buf should have been validated by 430 * bpf_object__open_buffer(). 431 */ 432 obj->efile.elf = elf_memory(obj->efile.obj_buf, 433 obj->efile.obj_buf_sz); 434 } else { 435 obj->efile.fd = open(obj->path, O_RDONLY); 436 if (obj->efile.fd < 0) { 437 pr_warning("failed to open %s: %s\n", obj->path, 438 strerror(errno)); 439 return -errno; 440 } 441 442 obj->efile.elf = elf_begin(obj->efile.fd, 443 LIBBPF_ELF_C_READ_MMAP, 444 NULL); 445 } 446 447 if (!obj->efile.elf) { 448 pr_warning("failed to open %s as ELF file\n", 449 obj->path); 450 err = -LIBBPF_ERRNO__LIBELF; 451 goto errout; 452 } 453 454 if (!gelf_getehdr(obj->efile.elf, &obj->efile.ehdr)) { 455 pr_warning("failed to get EHDR from %s\n", 456 obj->path); 457 err = -LIBBPF_ERRNO__FORMAT; 458 goto errout; 459 } 460 ep = &obj->efile.ehdr; 461 462 /* Old LLVM set e_machine to EM_NONE */ 463 if ((ep->e_type != ET_REL) || (ep->e_machine && (ep->e_machine != EM_BPF))) { 464 pr_warning("%s is not an eBPF object file\n", 465 obj->path); 466 err = -LIBBPF_ERRNO__FORMAT; 467 goto errout; 468 } 469 470 return 0; 471 errout: 472 bpf_object__elf_finish(obj); 473 return err; 474 } 475 476 static int 477 bpf_object__check_endianness(struct bpf_object *obj) 478 { 479 static unsigned int const endian = 1; 480 481 switch (obj->efile.ehdr.e_ident[EI_DATA]) { 482 case ELFDATA2LSB: 483 /* We are big endian, BPF obj is little endian. */ 484 if (*(unsigned char const *)&endian != 1) 485 goto mismatch; 486 break; 487 488 case ELFDATA2MSB: 489 /* We are little endian, BPF obj is big endian. */ 490 if (*(unsigned char const *)&endian != 0) 491 goto mismatch; 492 break; 493 default: 494 return -LIBBPF_ERRNO__ENDIAN; 495 } 496 497 return 0; 498 499 mismatch: 500 pr_warning("Error: endianness mismatch.\n"); 501 return -LIBBPF_ERRNO__ENDIAN; 502 } 503 504 static int 505 bpf_object__init_license(struct bpf_object *obj, 506 void *data, size_t size) 507 { 508 memcpy(obj->license, data, 509 min(size, sizeof(obj->license) - 1)); 510 pr_debug("license of %s is %s\n", obj->path, obj->license); 511 return 0; 512 } 513 514 static int 515 bpf_object__init_kversion(struct bpf_object *obj, 516 void *data, size_t size) 517 { 518 u32 kver; 519 520 if (size != sizeof(kver)) { 521 pr_warning("invalid kver section in %s\n", obj->path); 522 return -LIBBPF_ERRNO__FORMAT; 523 } 524 memcpy(&kver, data, sizeof(kver)); 525 obj->kern_version = kver; 526 pr_debug("kernel version of %s is %x\n", obj->path, 527 obj->kern_version); 528 return 0; 529 } 530 531 static int 532 bpf_object__validate_maps(struct bpf_object *obj) 533 { 534 int i; 535 536 /* 537 * If there's only 1 map, the only error case should have been 538 * catched in bpf_object__init_maps(). 539 */ 540 if (!obj->maps || !obj->nr_maps || (obj->nr_maps == 1)) 541 return 0; 542 543 for (i = 1; i < obj->nr_maps; i++) { 544 const struct bpf_map *a = &obj->maps[i - 1]; 545 const struct bpf_map *b = &obj->maps[i]; 546 547 if (b->offset - a->offset < sizeof(struct bpf_map_def)) { 548 pr_warning("corrupted map section in %s: map \"%s\" too small\n", 549 obj->path, a->name); 550 return -EINVAL; 551 } 552 } 553 return 0; 554 } 555 556 static int compare_bpf_map(const void *_a, const void *_b) 557 { 558 const struct bpf_map *a = _a; 559 const struct bpf_map *b = _b; 560 561 return a->offset - b->offset; 562 } 563 564 static int 565 bpf_object__init_maps(struct bpf_object *obj) 566 { 567 int i, map_idx, nr_maps = 0; 568 Elf_Scn *scn; 569 Elf_Data *data; 570 Elf_Data *symbols = obj->efile.symbols; 571 572 if (obj->efile.maps_shndx < 0) 573 return -EINVAL; 574 if (!symbols) 575 return -EINVAL; 576 577 scn = elf_getscn(obj->efile.elf, obj->efile.maps_shndx); 578 if (scn) 579 data = elf_getdata(scn, NULL); 580 if (!scn || !data) { 581 pr_warning("failed to get Elf_Data from map section %d\n", 582 obj->efile.maps_shndx); 583 return -EINVAL; 584 } 585 586 /* 587 * Count number of maps. Each map has a name. 588 * Array of maps is not supported: only the first element is 589 * considered. 590 * 591 * TODO: Detect array of map and report error. 592 */ 593 for (i = 0; i < symbols->d_size / sizeof(GElf_Sym); i++) { 594 GElf_Sym sym; 595 596 if (!gelf_getsym(symbols, i, &sym)) 597 continue; 598 if (sym.st_shndx != obj->efile.maps_shndx) 599 continue; 600 nr_maps++; 601 } 602 603 /* Alloc obj->maps and fill nr_maps. */ 604 pr_debug("maps in %s: %d maps in %zd bytes\n", obj->path, 605 nr_maps, data->d_size); 606 607 if (!nr_maps) 608 return 0; 609 610 obj->maps = calloc(nr_maps, sizeof(obj->maps[0])); 611 if (!obj->maps) { 612 pr_warning("alloc maps for object failed\n"); 613 return -ENOMEM; 614 } 615 obj->nr_maps = nr_maps; 616 617 /* 618 * fill all fd with -1 so won't close incorrect 619 * fd (fd=0 is stdin) when failure (zclose won't close 620 * negative fd)). 621 */ 622 for (i = 0; i < nr_maps; i++) 623 obj->maps[i].fd = -1; 624 625 /* 626 * Fill obj->maps using data in "maps" section. 627 */ 628 for (i = 0, map_idx = 0; i < symbols->d_size / sizeof(GElf_Sym); i++) { 629 GElf_Sym sym; 630 const char *map_name; 631 struct bpf_map_def *def; 632 633 if (!gelf_getsym(symbols, i, &sym)) 634 continue; 635 if (sym.st_shndx != obj->efile.maps_shndx) 636 continue; 637 638 map_name = elf_strptr(obj->efile.elf, 639 obj->efile.strtabidx, 640 sym.st_name); 641 obj->maps[map_idx].offset = sym.st_value; 642 if (sym.st_value + sizeof(struct bpf_map_def) > data->d_size) { 643 pr_warning("corrupted maps section in %s: last map \"%s\" too small\n", 644 obj->path, map_name); 645 return -EINVAL; 646 } 647 648 obj->maps[map_idx].name = strdup(map_name); 649 if (!obj->maps[map_idx].name) { 650 pr_warning("failed to alloc map name\n"); 651 return -ENOMEM; 652 } 653 pr_debug("map %d is \"%s\"\n", map_idx, 654 obj->maps[map_idx].name); 655 def = (struct bpf_map_def *)(data->d_buf + sym.st_value); 656 obj->maps[map_idx].def = *def; 657 map_idx++; 658 } 659 660 qsort(obj->maps, obj->nr_maps, sizeof(obj->maps[0]), compare_bpf_map); 661 return bpf_object__validate_maps(obj); 662 } 663 664 static int bpf_object__elf_collect(struct bpf_object *obj) 665 { 666 Elf *elf = obj->efile.elf; 667 GElf_Ehdr *ep = &obj->efile.ehdr; 668 Elf_Scn *scn = NULL; 669 int idx = 0, err = 0; 670 671 /* Elf is corrupted/truncated, avoid calling elf_strptr. */ 672 if (!elf_rawdata(elf_getscn(elf, ep->e_shstrndx), NULL)) { 673 pr_warning("failed to get e_shstrndx from %s\n", 674 obj->path); 675 return -LIBBPF_ERRNO__FORMAT; 676 } 677 678 while ((scn = elf_nextscn(elf, scn)) != NULL) { 679 char *name; 680 GElf_Shdr sh; 681 Elf_Data *data; 682 683 idx++; 684 if (gelf_getshdr(scn, &sh) != &sh) { 685 pr_warning("failed to get section header from %s\n", 686 obj->path); 687 err = -LIBBPF_ERRNO__FORMAT; 688 goto out; 689 } 690 691 name = elf_strptr(elf, ep->e_shstrndx, sh.sh_name); 692 if (!name) { 693 pr_warning("failed to get section name from %s\n", 694 obj->path); 695 err = -LIBBPF_ERRNO__FORMAT; 696 goto out; 697 } 698 699 data = elf_getdata(scn, 0); 700 if (!data) { 701 pr_warning("failed to get section data from %s(%s)\n", 702 name, obj->path); 703 err = -LIBBPF_ERRNO__FORMAT; 704 goto out; 705 } 706 pr_debug("section %s, size %ld, link %d, flags %lx, type=%d\n", 707 name, (unsigned long)data->d_size, 708 (int)sh.sh_link, (unsigned long)sh.sh_flags, 709 (int)sh.sh_type); 710 711 if (strcmp(name, "license") == 0) 712 err = bpf_object__init_license(obj, 713 data->d_buf, 714 data->d_size); 715 else if (strcmp(name, "version") == 0) 716 err = bpf_object__init_kversion(obj, 717 data->d_buf, 718 data->d_size); 719 else if (strcmp(name, "maps") == 0) 720 obj->efile.maps_shndx = idx; 721 else if (sh.sh_type == SHT_SYMTAB) { 722 if (obj->efile.symbols) { 723 pr_warning("bpf: multiple SYMTAB in %s\n", 724 obj->path); 725 err = -LIBBPF_ERRNO__FORMAT; 726 } else { 727 obj->efile.symbols = data; 728 obj->efile.strtabidx = sh.sh_link; 729 } 730 } else if ((sh.sh_type == SHT_PROGBITS) && 731 (sh.sh_flags & SHF_EXECINSTR) && 732 (data->d_size > 0)) { 733 err = bpf_object__add_program(obj, data->d_buf, 734 data->d_size, name, idx); 735 if (err) { 736 char errmsg[STRERR_BUFSIZE]; 737 738 strerror_r(-err, errmsg, sizeof(errmsg)); 739 pr_warning("failed to alloc program %s (%s): %s", 740 name, obj->path, errmsg); 741 } 742 } else if (sh.sh_type == SHT_REL) { 743 void *reloc = obj->efile.reloc; 744 int nr_reloc = obj->efile.nr_reloc + 1; 745 746 reloc = realloc(reloc, 747 sizeof(*obj->efile.reloc) * nr_reloc); 748 if (!reloc) { 749 pr_warning("realloc failed\n"); 750 err = -ENOMEM; 751 } else { 752 int n = nr_reloc - 1; 753 754 obj->efile.reloc = reloc; 755 obj->efile.nr_reloc = nr_reloc; 756 757 obj->efile.reloc[n].shdr = sh; 758 obj->efile.reloc[n].data = data; 759 } 760 } 761 if (err) 762 goto out; 763 } 764 765 if (!obj->efile.strtabidx || obj->efile.strtabidx >= idx) { 766 pr_warning("Corrupted ELF file: index of strtab invalid\n"); 767 return LIBBPF_ERRNO__FORMAT; 768 } 769 if (obj->efile.maps_shndx >= 0) 770 err = bpf_object__init_maps(obj); 771 out: 772 return err; 773 } 774 775 static struct bpf_program * 776 bpf_object__find_prog_by_idx(struct bpf_object *obj, int idx) 777 { 778 struct bpf_program *prog; 779 size_t i; 780 781 for (i = 0; i < obj->nr_programs; i++) { 782 prog = &obj->programs[i]; 783 if (prog->idx == idx) 784 return prog; 785 } 786 return NULL; 787 } 788 789 static int 790 bpf_program__collect_reloc(struct bpf_program *prog, 791 size_t nr_maps, GElf_Shdr *shdr, 792 Elf_Data *data, Elf_Data *symbols, 793 int maps_shndx, struct bpf_map *maps) 794 { 795 int i, nrels; 796 797 pr_debug("collecting relocating info for: '%s'\n", 798 prog->section_name); 799 nrels = shdr->sh_size / shdr->sh_entsize; 800 801 prog->reloc_desc = malloc(sizeof(*prog->reloc_desc) * nrels); 802 if (!prog->reloc_desc) { 803 pr_warning("failed to alloc memory in relocation\n"); 804 return -ENOMEM; 805 } 806 prog->nr_reloc = nrels; 807 808 for (i = 0; i < nrels; i++) { 809 GElf_Sym sym; 810 GElf_Rel rel; 811 unsigned int insn_idx; 812 struct bpf_insn *insns = prog->insns; 813 size_t map_idx; 814 815 if (!gelf_getrel(data, i, &rel)) { 816 pr_warning("relocation: failed to get %d reloc\n", i); 817 return -LIBBPF_ERRNO__FORMAT; 818 } 819 820 if (!gelf_getsym(symbols, 821 GELF_R_SYM(rel.r_info), 822 &sym)) { 823 pr_warning("relocation: symbol %"PRIx64" not found\n", 824 GELF_R_SYM(rel.r_info)); 825 return -LIBBPF_ERRNO__FORMAT; 826 } 827 828 if (sym.st_shndx != maps_shndx) { 829 pr_warning("Program '%s' contains non-map related relo data pointing to section %u\n", 830 prog->section_name, sym.st_shndx); 831 return -LIBBPF_ERRNO__RELOC; 832 } 833 834 insn_idx = rel.r_offset / sizeof(struct bpf_insn); 835 pr_debug("relocation: insn_idx=%u\n", insn_idx); 836 837 if (insns[insn_idx].code != (BPF_LD | BPF_IMM | BPF_DW)) { 838 pr_warning("bpf: relocation: invalid relo for insns[%d].code 0x%x\n", 839 insn_idx, insns[insn_idx].code); 840 return -LIBBPF_ERRNO__RELOC; 841 } 842 843 /* TODO: 'maps' is sorted. We can use bsearch to make it faster. */ 844 for (map_idx = 0; map_idx < nr_maps; map_idx++) { 845 if (maps[map_idx].offset == sym.st_value) { 846 pr_debug("relocation: find map %zd (%s) for insn %u\n", 847 map_idx, maps[map_idx].name, insn_idx); 848 break; 849 } 850 } 851 852 if (map_idx >= nr_maps) { 853 pr_warning("bpf relocation: map_idx %d large than %d\n", 854 (int)map_idx, (int)nr_maps - 1); 855 return -LIBBPF_ERRNO__RELOC; 856 } 857 858 prog->reloc_desc[i].insn_idx = insn_idx; 859 prog->reloc_desc[i].map_idx = map_idx; 860 } 861 return 0; 862 } 863 864 static int 865 bpf_object__create_maps(struct bpf_object *obj) 866 { 867 unsigned int i; 868 869 for (i = 0; i < obj->nr_maps; i++) { 870 struct bpf_map_def *def = &obj->maps[i].def; 871 int *pfd = &obj->maps[i].fd; 872 873 *pfd = bpf_create_map(def->type, 874 def->key_size, 875 def->value_size, 876 def->max_entries, 877 0); 878 if (*pfd < 0) { 879 size_t j; 880 int err = *pfd; 881 882 pr_warning("failed to create map (name: '%s'): %s\n", 883 obj->maps[i].name, 884 strerror(errno)); 885 for (j = 0; j < i; j++) 886 zclose(obj->maps[j].fd); 887 return err; 888 } 889 pr_debug("create map %s: fd=%d\n", obj->maps[i].name, *pfd); 890 } 891 892 return 0; 893 } 894 895 static int 896 bpf_program__relocate(struct bpf_program *prog, struct bpf_object *obj) 897 { 898 int i; 899 900 if (!prog || !prog->reloc_desc) 901 return 0; 902 903 for (i = 0; i < prog->nr_reloc; i++) { 904 int insn_idx, map_idx; 905 struct bpf_insn *insns = prog->insns; 906 907 insn_idx = prog->reloc_desc[i].insn_idx; 908 map_idx = prog->reloc_desc[i].map_idx; 909 910 if (insn_idx >= (int)prog->insns_cnt) { 911 pr_warning("relocation out of range: '%s'\n", 912 prog->section_name); 913 return -LIBBPF_ERRNO__RELOC; 914 } 915 insns[insn_idx].src_reg = BPF_PSEUDO_MAP_FD; 916 insns[insn_idx].imm = obj->maps[map_idx].fd; 917 } 918 919 zfree(&prog->reloc_desc); 920 prog->nr_reloc = 0; 921 return 0; 922 } 923 924 925 static int 926 bpf_object__relocate(struct bpf_object *obj) 927 { 928 struct bpf_program *prog; 929 size_t i; 930 int err; 931 932 for (i = 0; i < obj->nr_programs; i++) { 933 prog = &obj->programs[i]; 934 935 err = bpf_program__relocate(prog, obj); 936 if (err) { 937 pr_warning("failed to relocate '%s'\n", 938 prog->section_name); 939 return err; 940 } 941 } 942 return 0; 943 } 944 945 static int bpf_object__collect_reloc(struct bpf_object *obj) 946 { 947 int i, err; 948 949 if (!obj_elf_valid(obj)) { 950 pr_warning("Internal error: elf object is closed\n"); 951 return -LIBBPF_ERRNO__INTERNAL; 952 } 953 954 for (i = 0; i < obj->efile.nr_reloc; i++) { 955 GElf_Shdr *shdr = &obj->efile.reloc[i].shdr; 956 Elf_Data *data = obj->efile.reloc[i].data; 957 int idx = shdr->sh_info; 958 struct bpf_program *prog; 959 size_t nr_maps = obj->nr_maps; 960 961 if (shdr->sh_type != SHT_REL) { 962 pr_warning("internal error at %d\n", __LINE__); 963 return -LIBBPF_ERRNO__INTERNAL; 964 } 965 966 prog = bpf_object__find_prog_by_idx(obj, idx); 967 if (!prog) { 968 pr_warning("relocation failed: no %d section\n", 969 idx); 970 return -LIBBPF_ERRNO__RELOC; 971 } 972 973 err = bpf_program__collect_reloc(prog, nr_maps, 974 shdr, data, 975 obj->efile.symbols, 976 obj->efile.maps_shndx, 977 obj->maps); 978 if (err) 979 return err; 980 } 981 return 0; 982 } 983 984 static int 985 load_program(enum bpf_prog_type type, struct bpf_insn *insns, 986 int insns_cnt, char *license, u32 kern_version, int *pfd) 987 { 988 int ret; 989 char *log_buf; 990 991 if (!insns || !insns_cnt) 992 return -EINVAL; 993 994 log_buf = malloc(BPF_LOG_BUF_SIZE); 995 if (!log_buf) 996 pr_warning("Alloc log buffer for bpf loader error, continue without log\n"); 997 998 ret = bpf_load_program(type, insns, insns_cnt, license, 999 kern_version, log_buf, BPF_LOG_BUF_SIZE); 1000 1001 if (ret >= 0) { 1002 *pfd = ret; 1003 ret = 0; 1004 goto out; 1005 } 1006 1007 ret = -LIBBPF_ERRNO__LOAD; 1008 pr_warning("load bpf program failed: %s\n", strerror(errno)); 1009 1010 if (log_buf && log_buf[0] != '\0') { 1011 ret = -LIBBPF_ERRNO__VERIFY; 1012 pr_warning("-- BEGIN DUMP LOG ---\n"); 1013 pr_warning("\n%s\n", log_buf); 1014 pr_warning("-- END LOG --\n"); 1015 } else if (insns_cnt >= BPF_MAXINSNS) { 1016 pr_warning("Program too large (%d insns), at most %d insns\n", 1017 insns_cnt, BPF_MAXINSNS); 1018 ret = -LIBBPF_ERRNO__PROG2BIG; 1019 } else { 1020 /* Wrong program type? */ 1021 if (type != BPF_PROG_TYPE_KPROBE) { 1022 int fd; 1023 1024 fd = bpf_load_program(BPF_PROG_TYPE_KPROBE, insns, 1025 insns_cnt, license, kern_version, 1026 NULL, 0); 1027 if (fd >= 0) { 1028 close(fd); 1029 ret = -LIBBPF_ERRNO__PROGTYPE; 1030 goto out; 1031 } 1032 } 1033 1034 if (log_buf) 1035 ret = -LIBBPF_ERRNO__KVER; 1036 } 1037 1038 out: 1039 free(log_buf); 1040 return ret; 1041 } 1042 1043 static int 1044 bpf_program__load(struct bpf_program *prog, 1045 char *license, u32 kern_version) 1046 { 1047 int err = 0, fd, i; 1048 1049 if (prog->instances.nr < 0 || !prog->instances.fds) { 1050 if (prog->preprocessor) { 1051 pr_warning("Internal error: can't load program '%s'\n", 1052 prog->section_name); 1053 return -LIBBPF_ERRNO__INTERNAL; 1054 } 1055 1056 prog->instances.fds = malloc(sizeof(int)); 1057 if (!prog->instances.fds) { 1058 pr_warning("Not enough memory for BPF fds\n"); 1059 return -ENOMEM; 1060 } 1061 prog->instances.nr = 1; 1062 prog->instances.fds[0] = -1; 1063 } 1064 1065 if (!prog->preprocessor) { 1066 if (prog->instances.nr != 1) { 1067 pr_warning("Program '%s' is inconsistent: nr(%d) != 1\n", 1068 prog->section_name, prog->instances.nr); 1069 } 1070 err = load_program(prog->type, prog->insns, prog->insns_cnt, 1071 license, kern_version, &fd); 1072 if (!err) 1073 prog->instances.fds[0] = fd; 1074 goto out; 1075 } 1076 1077 for (i = 0; i < prog->instances.nr; i++) { 1078 struct bpf_prog_prep_result result; 1079 bpf_program_prep_t preprocessor = prog->preprocessor; 1080 1081 bzero(&result, sizeof(result)); 1082 err = preprocessor(prog, i, prog->insns, 1083 prog->insns_cnt, &result); 1084 if (err) { 1085 pr_warning("Preprocessing the %dth instance of program '%s' failed\n", 1086 i, prog->section_name); 1087 goto out; 1088 } 1089 1090 if (!result.new_insn_ptr || !result.new_insn_cnt) { 1091 pr_debug("Skip loading the %dth instance of program '%s'\n", 1092 i, prog->section_name); 1093 prog->instances.fds[i] = -1; 1094 if (result.pfd) 1095 *result.pfd = -1; 1096 continue; 1097 } 1098 1099 err = load_program(prog->type, result.new_insn_ptr, 1100 result.new_insn_cnt, 1101 license, kern_version, &fd); 1102 1103 if (err) { 1104 pr_warning("Loading the %dth instance of program '%s' failed\n", 1105 i, prog->section_name); 1106 goto out; 1107 } 1108 1109 if (result.pfd) 1110 *result.pfd = fd; 1111 prog->instances.fds[i] = fd; 1112 } 1113 out: 1114 if (err) 1115 pr_warning("failed to load program '%s'\n", 1116 prog->section_name); 1117 zfree(&prog->insns); 1118 prog->insns_cnt = 0; 1119 return err; 1120 } 1121 1122 static int 1123 bpf_object__load_progs(struct bpf_object *obj) 1124 { 1125 size_t i; 1126 int err; 1127 1128 for (i = 0; i < obj->nr_programs; i++) { 1129 err = bpf_program__load(&obj->programs[i], 1130 obj->license, 1131 obj->kern_version); 1132 if (err) 1133 return err; 1134 } 1135 return 0; 1136 } 1137 1138 static int bpf_object__validate(struct bpf_object *obj) 1139 { 1140 if (obj->kern_version == 0) { 1141 pr_warning("%s doesn't provide kernel version\n", 1142 obj->path); 1143 return -LIBBPF_ERRNO__KVERSION; 1144 } 1145 return 0; 1146 } 1147 1148 static struct bpf_object * 1149 __bpf_object__open(const char *path, void *obj_buf, size_t obj_buf_sz) 1150 { 1151 struct bpf_object *obj; 1152 int err; 1153 1154 if (elf_version(EV_CURRENT) == EV_NONE) { 1155 pr_warning("failed to init libelf for %s\n", path); 1156 return ERR_PTR(-LIBBPF_ERRNO__LIBELF); 1157 } 1158 1159 obj = bpf_object__new(path, obj_buf, obj_buf_sz); 1160 if (IS_ERR(obj)) 1161 return obj; 1162 1163 CHECK_ERR(bpf_object__elf_init(obj), err, out); 1164 CHECK_ERR(bpf_object__check_endianness(obj), err, out); 1165 CHECK_ERR(bpf_object__elf_collect(obj), err, out); 1166 CHECK_ERR(bpf_object__collect_reloc(obj), err, out); 1167 CHECK_ERR(bpf_object__validate(obj), err, out); 1168 1169 bpf_object__elf_finish(obj); 1170 return obj; 1171 out: 1172 bpf_object__close(obj); 1173 return ERR_PTR(err); 1174 } 1175 1176 struct bpf_object *bpf_object__open(const char *path) 1177 { 1178 /* param validation */ 1179 if (!path) 1180 return NULL; 1181 1182 pr_debug("loading %s\n", path); 1183 1184 return __bpf_object__open(path, NULL, 0); 1185 } 1186 1187 struct bpf_object *bpf_object__open_buffer(void *obj_buf, 1188 size_t obj_buf_sz, 1189 const char *name) 1190 { 1191 char tmp_name[64]; 1192 1193 /* param validation */ 1194 if (!obj_buf || obj_buf_sz <= 0) 1195 return NULL; 1196 1197 if (!name) { 1198 snprintf(tmp_name, sizeof(tmp_name), "%lx-%lx", 1199 (unsigned long)obj_buf, 1200 (unsigned long)obj_buf_sz); 1201 tmp_name[sizeof(tmp_name) - 1] = '\0'; 1202 name = tmp_name; 1203 } 1204 pr_debug("loading object '%s' from buffer\n", 1205 name); 1206 1207 return __bpf_object__open(name, obj_buf, obj_buf_sz); 1208 } 1209 1210 int bpf_object__unload(struct bpf_object *obj) 1211 { 1212 size_t i; 1213 1214 if (!obj) 1215 return -EINVAL; 1216 1217 for (i = 0; i < obj->nr_maps; i++) 1218 zclose(obj->maps[i].fd); 1219 1220 for (i = 0; i < obj->nr_programs; i++) 1221 bpf_program__unload(&obj->programs[i]); 1222 1223 return 0; 1224 } 1225 1226 int bpf_object__load(struct bpf_object *obj) 1227 { 1228 int err; 1229 1230 if (!obj) 1231 return -EINVAL; 1232 1233 if (obj->loaded) { 1234 pr_warning("object should not be loaded twice\n"); 1235 return -EINVAL; 1236 } 1237 1238 obj->loaded = true; 1239 1240 CHECK_ERR(bpf_object__create_maps(obj), err, out); 1241 CHECK_ERR(bpf_object__relocate(obj), err, out); 1242 CHECK_ERR(bpf_object__load_progs(obj), err, out); 1243 1244 return 0; 1245 out: 1246 bpf_object__unload(obj); 1247 pr_warning("failed to load object '%s'\n", obj->path); 1248 return err; 1249 } 1250 1251 static int check_path(const char *path) 1252 { 1253 struct statfs st_fs; 1254 char *dname, *dir; 1255 int err = 0; 1256 1257 if (path == NULL) 1258 return -EINVAL; 1259 1260 dname = strdup(path); 1261 if (dname == NULL) 1262 return -ENOMEM; 1263 1264 dir = dirname(dname); 1265 if (statfs(dir, &st_fs)) { 1266 pr_warning("failed to statfs %s: %s\n", dir, strerror(errno)); 1267 err = -errno; 1268 } 1269 free(dname); 1270 1271 if (!err && st_fs.f_type != BPF_FS_MAGIC) { 1272 pr_warning("specified path %s is not on BPF FS\n", path); 1273 err = -EINVAL; 1274 } 1275 1276 return err; 1277 } 1278 1279 int bpf_program__pin_instance(struct bpf_program *prog, const char *path, 1280 int instance) 1281 { 1282 int err; 1283 1284 err = check_path(path); 1285 if (err) 1286 return err; 1287 1288 if (prog == NULL) { 1289 pr_warning("invalid program pointer\n"); 1290 return -EINVAL; 1291 } 1292 1293 if (instance < 0 || instance >= prog->instances.nr) { 1294 pr_warning("invalid prog instance %d of prog %s (max %d)\n", 1295 instance, prog->section_name, prog->instances.nr); 1296 return -EINVAL; 1297 } 1298 1299 if (bpf_obj_pin(prog->instances.fds[instance], path)) { 1300 pr_warning("failed to pin program: %s\n", strerror(errno)); 1301 return -errno; 1302 } 1303 pr_debug("pinned program '%s'\n", path); 1304 1305 return 0; 1306 } 1307 1308 static int make_dir(const char *path) 1309 { 1310 int err = 0; 1311 1312 if (mkdir(path, 0700) && errno != EEXIST) 1313 err = -errno; 1314 1315 if (err) 1316 pr_warning("failed to mkdir %s: %s\n", path, strerror(-err)); 1317 return err; 1318 } 1319 1320 int bpf_program__pin(struct bpf_program *prog, const char *path) 1321 { 1322 int i, err; 1323 1324 err = check_path(path); 1325 if (err) 1326 return err; 1327 1328 if (prog == NULL) { 1329 pr_warning("invalid program pointer\n"); 1330 return -EINVAL; 1331 } 1332 1333 if (prog->instances.nr <= 0) { 1334 pr_warning("no instances of prog %s to pin\n", 1335 prog->section_name); 1336 return -EINVAL; 1337 } 1338 1339 err = make_dir(path); 1340 if (err) 1341 return err; 1342 1343 for (i = 0; i < prog->instances.nr; i++) { 1344 char buf[PATH_MAX]; 1345 int len; 1346 1347 len = snprintf(buf, PATH_MAX, "%s/%d", path, i); 1348 if (len < 0) 1349 return -EINVAL; 1350 else if (len >= PATH_MAX) 1351 return -ENAMETOOLONG; 1352 1353 err = bpf_program__pin_instance(prog, buf, i); 1354 if (err) 1355 return err; 1356 } 1357 1358 return 0; 1359 } 1360 1361 int bpf_map__pin(struct bpf_map *map, const char *path) 1362 { 1363 int err; 1364 1365 err = check_path(path); 1366 if (err) 1367 return err; 1368 1369 if (map == NULL) { 1370 pr_warning("invalid map pointer\n"); 1371 return -EINVAL; 1372 } 1373 1374 if (bpf_obj_pin(map->fd, path)) { 1375 pr_warning("failed to pin map: %s\n", strerror(errno)); 1376 return -errno; 1377 } 1378 1379 pr_debug("pinned map '%s'\n", path); 1380 return 0; 1381 } 1382 1383 int bpf_object__pin(struct bpf_object *obj, const char *path) 1384 { 1385 struct bpf_program *prog; 1386 struct bpf_map *map; 1387 int err; 1388 1389 if (!obj) 1390 return -ENOENT; 1391 1392 if (!obj->loaded) { 1393 pr_warning("object not yet loaded; load it first\n"); 1394 return -ENOENT; 1395 } 1396 1397 err = make_dir(path); 1398 if (err) 1399 return err; 1400 1401 bpf_map__for_each(map, obj) { 1402 char buf[PATH_MAX]; 1403 int len; 1404 1405 len = snprintf(buf, PATH_MAX, "%s/%s", path, 1406 bpf_map__name(map)); 1407 if (len < 0) 1408 return -EINVAL; 1409 else if (len >= PATH_MAX) 1410 return -ENAMETOOLONG; 1411 1412 err = bpf_map__pin(map, buf); 1413 if (err) 1414 return err; 1415 } 1416 1417 bpf_object__for_each_program(prog, obj) { 1418 char buf[PATH_MAX]; 1419 int len; 1420 1421 len = snprintf(buf, PATH_MAX, "%s/%s", path, 1422 prog->section_name); 1423 if (len < 0) 1424 return -EINVAL; 1425 else if (len >= PATH_MAX) 1426 return -ENAMETOOLONG; 1427 1428 err = bpf_program__pin(prog, buf); 1429 if (err) 1430 return err; 1431 } 1432 1433 return 0; 1434 } 1435 1436 void bpf_object__close(struct bpf_object *obj) 1437 { 1438 size_t i; 1439 1440 if (!obj) 1441 return; 1442 1443 if (obj->clear_priv) 1444 obj->clear_priv(obj, obj->priv); 1445 1446 bpf_object__elf_finish(obj); 1447 bpf_object__unload(obj); 1448 1449 for (i = 0; i < obj->nr_maps; i++) { 1450 zfree(&obj->maps[i].name); 1451 if (obj->maps[i].clear_priv) 1452 obj->maps[i].clear_priv(&obj->maps[i], 1453 obj->maps[i].priv); 1454 obj->maps[i].priv = NULL; 1455 obj->maps[i].clear_priv = NULL; 1456 } 1457 zfree(&obj->maps); 1458 obj->nr_maps = 0; 1459 1460 if (obj->programs && obj->nr_programs) { 1461 for (i = 0; i < obj->nr_programs; i++) 1462 bpf_program__exit(&obj->programs[i]); 1463 } 1464 zfree(&obj->programs); 1465 1466 list_del(&obj->list); 1467 free(obj); 1468 } 1469 1470 struct bpf_object * 1471 bpf_object__next(struct bpf_object *prev) 1472 { 1473 struct bpf_object *next; 1474 1475 if (!prev) 1476 next = list_first_entry(&bpf_objects_list, 1477 struct bpf_object, 1478 list); 1479 else 1480 next = list_next_entry(prev, list); 1481 1482 /* Empty list is noticed here so don't need checking on entry. */ 1483 if (&next->list == &bpf_objects_list) 1484 return NULL; 1485 1486 return next; 1487 } 1488 1489 const char *bpf_object__name(struct bpf_object *obj) 1490 { 1491 return obj ? obj->path : ERR_PTR(-EINVAL); 1492 } 1493 1494 unsigned int bpf_object__kversion(struct bpf_object *obj) 1495 { 1496 return obj ? obj->kern_version : 0; 1497 } 1498 1499 int bpf_object__set_priv(struct bpf_object *obj, void *priv, 1500 bpf_object_clear_priv_t clear_priv) 1501 { 1502 if (obj->priv && obj->clear_priv) 1503 obj->clear_priv(obj, obj->priv); 1504 1505 obj->priv = priv; 1506 obj->clear_priv = clear_priv; 1507 return 0; 1508 } 1509 1510 void *bpf_object__priv(struct bpf_object *obj) 1511 { 1512 return obj ? obj->priv : ERR_PTR(-EINVAL); 1513 } 1514 1515 struct bpf_program * 1516 bpf_program__next(struct bpf_program *prev, struct bpf_object *obj) 1517 { 1518 size_t idx; 1519 1520 if (!obj->programs) 1521 return NULL; 1522 /* First handler */ 1523 if (prev == NULL) 1524 return &obj->programs[0]; 1525 1526 if (prev->obj != obj) { 1527 pr_warning("error: program handler doesn't match object\n"); 1528 return NULL; 1529 } 1530 1531 idx = (prev - obj->programs) + 1; 1532 if (idx >= obj->nr_programs) 1533 return NULL; 1534 return &obj->programs[idx]; 1535 } 1536 1537 int bpf_program__set_priv(struct bpf_program *prog, void *priv, 1538 bpf_program_clear_priv_t clear_priv) 1539 { 1540 if (prog->priv && prog->clear_priv) 1541 prog->clear_priv(prog, prog->priv); 1542 1543 prog->priv = priv; 1544 prog->clear_priv = clear_priv; 1545 return 0; 1546 } 1547 1548 void *bpf_program__priv(struct bpf_program *prog) 1549 { 1550 return prog ? prog->priv : ERR_PTR(-EINVAL); 1551 } 1552 1553 const char *bpf_program__title(struct bpf_program *prog, bool needs_copy) 1554 { 1555 const char *title; 1556 1557 title = prog->section_name; 1558 if (needs_copy) { 1559 title = strdup(title); 1560 if (!title) { 1561 pr_warning("failed to strdup program title\n"); 1562 return ERR_PTR(-ENOMEM); 1563 } 1564 } 1565 1566 return title; 1567 } 1568 1569 int bpf_program__fd(struct bpf_program *prog) 1570 { 1571 return bpf_program__nth_fd(prog, 0); 1572 } 1573 1574 int bpf_program__set_prep(struct bpf_program *prog, int nr_instances, 1575 bpf_program_prep_t prep) 1576 { 1577 int *instances_fds; 1578 1579 if (nr_instances <= 0 || !prep) 1580 return -EINVAL; 1581 1582 if (prog->instances.nr > 0 || prog->instances.fds) { 1583 pr_warning("Can't set pre-processor after loading\n"); 1584 return -EINVAL; 1585 } 1586 1587 instances_fds = malloc(sizeof(int) * nr_instances); 1588 if (!instances_fds) { 1589 pr_warning("alloc memory failed for fds\n"); 1590 return -ENOMEM; 1591 } 1592 1593 /* fill all fd with -1 */ 1594 memset(instances_fds, -1, sizeof(int) * nr_instances); 1595 1596 prog->instances.nr = nr_instances; 1597 prog->instances.fds = instances_fds; 1598 prog->preprocessor = prep; 1599 return 0; 1600 } 1601 1602 int bpf_program__nth_fd(struct bpf_program *prog, int n) 1603 { 1604 int fd; 1605 1606 if (n >= prog->instances.nr || n < 0) { 1607 pr_warning("Can't get the %dth fd from program %s: only %d instances\n", 1608 n, prog->section_name, prog->instances.nr); 1609 return -EINVAL; 1610 } 1611 1612 fd = prog->instances.fds[n]; 1613 if (fd < 0) { 1614 pr_warning("%dth instance of program '%s' is invalid\n", 1615 n, prog->section_name); 1616 return -ENOENT; 1617 } 1618 1619 return fd; 1620 } 1621 1622 void bpf_program__set_type(struct bpf_program *prog, enum bpf_prog_type type) 1623 { 1624 prog->type = type; 1625 } 1626 1627 static bool bpf_program__is_type(struct bpf_program *prog, 1628 enum bpf_prog_type type) 1629 { 1630 return prog ? (prog->type == type) : false; 1631 } 1632 1633 #define BPF_PROG_TYPE_FNS(NAME, TYPE) \ 1634 int bpf_program__set_##NAME(struct bpf_program *prog) \ 1635 { \ 1636 if (!prog) \ 1637 return -EINVAL; \ 1638 bpf_program__set_type(prog, TYPE); \ 1639 return 0; \ 1640 } \ 1641 \ 1642 bool bpf_program__is_##NAME(struct bpf_program *prog) \ 1643 { \ 1644 return bpf_program__is_type(prog, TYPE); \ 1645 } \ 1646 1647 BPF_PROG_TYPE_FNS(socket_filter, BPF_PROG_TYPE_SOCKET_FILTER); 1648 BPF_PROG_TYPE_FNS(kprobe, BPF_PROG_TYPE_KPROBE); 1649 BPF_PROG_TYPE_FNS(sched_cls, BPF_PROG_TYPE_SCHED_CLS); 1650 BPF_PROG_TYPE_FNS(sched_act, BPF_PROG_TYPE_SCHED_ACT); 1651 BPF_PROG_TYPE_FNS(tracepoint, BPF_PROG_TYPE_TRACEPOINT); 1652 BPF_PROG_TYPE_FNS(xdp, BPF_PROG_TYPE_XDP); 1653 BPF_PROG_TYPE_FNS(perf_event, BPF_PROG_TYPE_PERF_EVENT); 1654 1655 int bpf_map__fd(struct bpf_map *map) 1656 { 1657 return map ? map->fd : -EINVAL; 1658 } 1659 1660 const struct bpf_map_def *bpf_map__def(struct bpf_map *map) 1661 { 1662 return map ? &map->def : ERR_PTR(-EINVAL); 1663 } 1664 1665 const char *bpf_map__name(struct bpf_map *map) 1666 { 1667 return map ? map->name : NULL; 1668 } 1669 1670 int bpf_map__set_priv(struct bpf_map *map, void *priv, 1671 bpf_map_clear_priv_t clear_priv) 1672 { 1673 if (!map) 1674 return -EINVAL; 1675 1676 if (map->priv) { 1677 if (map->clear_priv) 1678 map->clear_priv(map, map->priv); 1679 } 1680 1681 map->priv = priv; 1682 map->clear_priv = clear_priv; 1683 return 0; 1684 } 1685 1686 void *bpf_map__priv(struct bpf_map *map) 1687 { 1688 return map ? map->priv : ERR_PTR(-EINVAL); 1689 } 1690 1691 struct bpf_map * 1692 bpf_map__next(struct bpf_map *prev, struct bpf_object *obj) 1693 { 1694 size_t idx; 1695 struct bpf_map *s, *e; 1696 1697 if (!obj || !obj->maps) 1698 return NULL; 1699 1700 s = obj->maps; 1701 e = obj->maps + obj->nr_maps; 1702 1703 if (prev == NULL) 1704 return s; 1705 1706 if ((prev < s) || (prev >= e)) { 1707 pr_warning("error in %s: map handler doesn't belong to object\n", 1708 __func__); 1709 return NULL; 1710 } 1711 1712 idx = (prev - obj->maps) + 1; 1713 if (idx >= obj->nr_maps) 1714 return NULL; 1715 return &obj->maps[idx]; 1716 } 1717 1718 struct bpf_map * 1719 bpf_object__find_map_by_name(struct bpf_object *obj, const char *name) 1720 { 1721 struct bpf_map *pos; 1722 1723 bpf_map__for_each(pos, obj) { 1724 if (pos->name && !strcmp(pos->name, name)) 1725 return pos; 1726 } 1727 return NULL; 1728 } 1729 1730 struct bpf_map * 1731 bpf_object__find_map_by_offset(struct bpf_object *obj, size_t offset) 1732 { 1733 int i; 1734 1735 for (i = 0; i < obj->nr_maps; i++) { 1736 if (obj->maps[i].offset == offset) 1737 return &obj->maps[i]; 1738 } 1739 return ERR_PTR(-ENOENT); 1740 } 1741 1742 long libbpf_get_error(const void *ptr) 1743 { 1744 if (IS_ERR(ptr)) 1745 return PTR_ERR(ptr); 1746 return 0; 1747 } 1748 1749 int bpf_prog_load(const char *file, enum bpf_prog_type type, 1750 struct bpf_object **pobj, int *prog_fd) 1751 { 1752 struct bpf_program *prog; 1753 struct bpf_object *obj; 1754 int err; 1755 1756 obj = bpf_object__open(file); 1757 if (IS_ERR(obj)) 1758 return -ENOENT; 1759 1760 prog = bpf_program__next(NULL, obj); 1761 if (!prog) { 1762 bpf_object__close(obj); 1763 return -ENOENT; 1764 } 1765 1766 bpf_program__set_type(prog, type); 1767 err = bpf_object__load(obj); 1768 if (err) { 1769 bpf_object__close(obj); 1770 return -EINVAL; 1771 } 1772 1773 *pobj = obj; 1774 *prog_fd = bpf_program__fd(prog); 1775 return 0; 1776 } 1777