tools/lib/bpf/libbpf.c

   1 // SPDX-License-Identifier: LGPL-2.1
   2
   3 /*
   4  * Common eBPF ELF object loading operations.
   5  *
   6  * Copyright (C) 2013-2015 Alexei Starovoitov <ast@kernel.org>
   7  * Copyright (C) 2015 Wang Nan <wangnan0@huawei.com>
   8  * Copyright (C) 2015 Huawei Inc.
   9  * Copyright (C) 2017 Nicira, Inc.
  10  *
  11  * This program is free software; you can redistribute it and/or
  12  * modify it under the terms of the GNU Lesser General Public
  13  * License as published by the Free Software Foundation;
  14  * version 2.1 of the License (not later!)
  15  *
  16  * This program is distributed in the hope that it will be useful,
  17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19  * GNU Lesser General Public License for more details.
  20  *
  21  * You should have received a copy of the GNU Lesser General Public
  22  * License along with this program; if not,  see <http://www.gnu.org/licenses>
  23  */
  24
  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 <asm/unistd.h>
  35 #include <linux/err.h>
  36 #include <linux/kernel.h>
  37 #include <linux/bpf.h>
  38 #include <linux/list.h>
  39 #include <linux/limits.h>
  40 #include <sys/stat.h>
  41 #include <sys/types.h>
  42 #include <sys/vfs.h>
  43 #include <libelf.h>
  44 #include <gelf.h>
  45
  46 #include "libbpf.h"
  47 #include "bpf.h"
  48
  49 #ifndef EM_BPF
  50 #define EM_BPF 247
  51 #endif
  52
  53 #ifndef BPF_FS_MAGIC
  54 #define BPF_FS_MAGIC            0xcafe4a11
  55 #endif
  56
  57 #define __printf(a, b)  __attribute__((format(printf, a, b)))
  58
  59 __printf(1, 2)
  60 static int __base_pr(const char *format, ...)
  61 {
  62         va_list args;
  63         int err;
  64
  65         va_start(args, format);
  66         err = vfprintf(stderr, format, args);
  67         va_end(args);
  68         return err;
  69 }
  70
  71 static __printf(1, 2) libbpf_print_fn_t __pr_warning = __base_pr;
  72 static __printf(1, 2) libbpf_print_fn_t __pr_info = __base_pr;
  73 static __printf(1, 2) libbpf_print_fn_t __pr_debug;
  74
  75 #define __pr(func, fmt, ...)    \
  76 do {                            \
  77         if ((func))             \
  78                 (func)("libbpf: " fmt, ##__VA_ARGS__); \
  79 } while (0)
  80
  81 #define pr_warning(fmt, ...)    __pr(__pr_warning, fmt, ##__VA_ARGS__)
  82 #define pr_info(fmt, ...)       __pr(__pr_info, fmt, ##__VA_ARGS__)
  83 #define pr_debug(fmt, ...)      __pr(__pr_debug, fmt, ##__VA_ARGS__)
  84
  85 void libbpf_set_print(libbpf_print_fn_t warn,
  86                       libbpf_print_fn_t info,
  87                       libbpf_print_fn_t debug)
  88 {
  89         __pr_warning = warn;
  90         __pr_info = info;
  91         __pr_debug = debug;
  92 }
  93
  94 #define STRERR_BUFSIZE  128
  95
  96 #define ERRNO_OFFSET(e)         ((e) - __LIBBPF_ERRNO__START)
  97 #define ERRCODE_OFFSET(c)       ERRNO_OFFSET(LIBBPF_ERRNO__##c)
  98 #define NR_ERRNO        (__LIBBPF_ERRNO__END - __LIBBPF_ERRNO__START)
  99
 100 static const char *libbpf_strerror_table[NR_ERRNO] = {
 101         [ERRCODE_OFFSET(LIBELF)]        = "Something wrong in libelf",
 102         [ERRCODE_OFFSET(FORMAT)]        = "BPF object format invalid",
 103         [ERRCODE_OFFSET(KVERSION)]      = "'version' section incorrect or lost",
 104         [ERRCODE_OFFSET(ENDIAN)]        = "Endian mismatch",
 105         [ERRCODE_OFFSET(INTERNAL)]      = "Internal error in libbpf",
 106         [ERRCODE_OFFSET(RELOC)]         = "Relocation failed",
 107         [ERRCODE_OFFSET(VERIFY)]        = "Kernel verifier blocks program loading",
 108         [ERRCODE_OFFSET(PROG2BIG)]      = "Program too big",
 109         [ERRCODE_OFFSET(KVER)]          = "Incorrect kernel version",
 110         [ERRCODE_OFFSET(PROGTYPE)]      = "Kernel doesn't support this program type",
 111         [ERRCODE_OFFSET(WRNGPID)]       = "Wrong pid in netlink message",
 112         [ERRCODE_OFFSET(INVSEQ)]        = "Invalid netlink sequence",
 113 };
 114
 115 int libbpf_strerror(int err, char *buf, size_t size)
 116 {
 117         if (!buf || !size)
 118                 return -1;
 119
 120         err = err > 0 ? err : -err;
 121
 122         if (err < __LIBBPF_ERRNO__START) {
 123                 int ret;
 124
 125                 ret = strerror_r(err, buf, size);
 126                 buf[size - 1] = '\0';
 127                 return ret;
 128         }
 129
 130         if (err < __LIBBPF_ERRNO__END) {
 131                 const char *msg;
 132
 133                 msg = libbpf_strerror_table[ERRNO_OFFSET(err)];
 134                 snprintf(buf, size, "%s", msg);
 135                 buf[size - 1] = '\0';
 136                 return 0;
 137         }
 138
 139         snprintf(buf, size, "Unknown libbpf error %d", err);
 140         buf[size - 1] = '\0';
 141         return -1;
 142 }
 143
 144 #define CHECK_ERR(action, err, out) do {        \
 145         err = action;                   \
 146         if (err)                        \
 147                 goto out;               \
 148 } while(0)
 149
 150
 151 /* Copied from tools/perf/util/util.h */
 152 #ifndef zfree
 153 # define zfree(ptr) ({ free(*ptr); *ptr = NULL; })
 154 #endif
 155
 156 #ifndef zclose
 157 # define zclose(fd) ({                  \
 158         int ___err = 0;                 \
 159         if ((fd) >= 0)                  \
 160                 ___err = close((fd));   \
 161         fd = -1;                        \
 162         ___err; })
 163 #endif
 164
 165 #ifdef HAVE_LIBELF_MMAP_SUPPORT
 166 # define LIBBPF_ELF_C_READ_MMAP ELF_C_READ_MMAP
 167 #else
 168 # define LIBBPF_ELF_C_READ_MMAP ELF_C_READ
 169 #endif
 170
 171 /*
 172  * bpf_prog should be a better name but it has been used in
 173  * linux/filter.h.
 174  */
 175 struct bpf_program {
 176         /* Index in elf obj file, for relocation use. */
 177         int idx;
 178         char *name;
 179         char *section_name;
 180         struct bpf_insn *insns;
 181         size_t insns_cnt, main_prog_cnt;
 182         enum bpf_prog_type type;
 183
 184         struct reloc_desc {
 185                 enum {
 186                         RELO_LD64,
 187                         RELO_CALL,
 188                 } type;
 189                 int insn_idx;
 190                 union {
 191                         int map_idx;
 192                         int text_off;
 193                 };
 194         } *reloc_desc;
 195         int nr_reloc;
 196
 197         struct {
 198                 int nr;
 199                 int *fds;
 200         } instances;
 201         bpf_program_prep_t preprocessor;
 202
 203         struct bpf_object *obj;
 204         void *priv;
 205         bpf_program_clear_priv_t clear_priv;
 206
 207         enum bpf_attach_type expected_attach_type;
 208 };
 209
 210 struct bpf_map {
 211         int fd;
 212         char *name;
 213         size_t offset;
 214         struct bpf_map_def def;
 215         void *priv;
 216         bpf_map_clear_priv_t clear_priv;
 217 };
 218
 219 static LIST_HEAD(bpf_objects_list);
 220
 221 struct bpf_object {
 222         char license[64];
 223         u32 kern_version;
 224
 225         struct bpf_program *programs;
 226         size_t nr_programs;
 227         struct bpf_map *maps;
 228         size_t nr_maps;
 229
 230         bool loaded;
 231
 232         /*
 233          * Information when doing elf related work. Only valid if fd
 234          * is valid.
 235          */
 236         struct {
 237                 int fd;
 238                 void *obj_buf;
 239                 size_t obj_buf_sz;
 240                 Elf *elf;
 241                 GElf_Ehdr ehdr;
 242                 Elf_Data *symbols;
 243                 size_t strtabidx;
 244                 struct {
 245                         GElf_Shdr shdr;
 246                         Elf_Data *data;
 247                 } *reloc;
 248                 int nr_reloc;
 249                 int maps_shndx;
 250                 int text_shndx;
 251         } efile;
 252         /*
 253          * All loaded bpf_object is linked in a list, which is
 254          * hidden to caller. bpf_objects__<func> handlers deal with
 255          * all objects.
 256          */
 257         struct list_head list;
 258
 259         void *priv;
 260         bpf_object_clear_priv_t clear_priv;
 261
 262         char path[];
 263 };
 264 #define obj_elf_valid(o)        ((o)->efile.elf)
 265
 266 static void bpf_program__unload(struct bpf_program *prog)
 267 {
 268         int i;
 269
 270         if (!prog)
 271                 return;
 272
 273         /*
 274          * If the object is opened but the program was never loaded,
 275          * it is possible that prog->instances.nr == -1.
 276          */
 277         if (prog->instances.nr > 0) {
 278                 for (i = 0; i < prog->instances.nr; i++)
 279                         zclose(prog->instances.fds[i]);
 280         } else if (prog->instances.nr != -1) {
 281                 pr_warning("Internal error: instances.nr is %d\n",
 282                            prog->instances.nr);
 283         }
 284
 285         prog->instances.nr = -1;
 286         zfree(&prog->instances.fds);
 287 }
 288
 289 static void bpf_program__exit(struct bpf_program *prog)
 290 {
 291         if (!prog)
 292                 return;
 293
 294         if (prog->clear_priv)
 295                 prog->clear_priv(prog, prog->priv);
 296
 297         prog->priv = NULL;
 298         prog->clear_priv = NULL;
 299
 300         bpf_program__unload(prog);
 301         zfree(&prog->name);
 302         zfree(&prog->section_name);
 303         zfree(&prog->insns);
 304         zfree(&prog->reloc_desc);
 305
 306         prog->nr_reloc = 0;
 307         prog->insns_cnt = 0;
 308         prog->idx = -1;
 309 }
 310
 311 static int
 312 bpf_program__init(void *data, size_t size, char *section_name, int idx,
 313                   struct bpf_program *prog)
 314 {
 315         if (size < sizeof(struct bpf_insn)) {
 316                 pr_warning("corrupted section '%s'\n", section_name);
 317                 return -EINVAL;
 318         }
 319
 320         bzero(prog, sizeof(*prog));
 321
 322         prog->section_name = strdup(section_name);
 323         if (!prog->section_name) {
 324                 pr_warning("failed to alloc name for prog under section(%d) %s\n",
 325                            idx, section_name);
 326                 goto errout;
 327         }
 328
 329         prog->insns = malloc(size);
 330         if (!prog->insns) {
 331                 pr_warning("failed to alloc insns for prog under section %s\n",
 332                            section_name);
 333                 goto errout;
 334         }
 335         prog->insns_cnt = size / sizeof(struct bpf_insn);
 336         memcpy(prog->insns, data,
 337                prog->insns_cnt * sizeof(struct bpf_insn));
 338         prog->idx = idx;
 339         prog->instances.fds = NULL;
 340         prog->instances.nr = -1;
 341         prog->type = BPF_PROG_TYPE_KPROBE;
 342
 343         return 0;
 344 errout:
 345         bpf_program__exit(prog);
 346         return -ENOMEM;
 347 }
 348
 349 static int
 350 bpf_object__add_program(struct bpf_object *obj, void *data, size_t size,
 351                         char *section_name, int idx)
 352 {
 353         struct bpf_program prog, *progs;
 354         int nr_progs, err;
 355
 356         err = bpf_program__init(data, size, section_name, idx, &prog);
 357         if (err)
 358                 return err;
 359
 360         progs = obj->programs;
 361         nr_progs = obj->nr_programs;
 362
 363         progs = realloc(progs, sizeof(progs[0]) * (nr_progs + 1));
 364         if (!progs) {
 365                 /*
 366                  * In this case the original obj->programs
 367                  * is still valid, so don't need special treat for
 368                  * bpf_close_object().
 369                  */
 370                 pr_warning("failed to alloc a new program under section '%s'\n",
 371                            section_name);
 372                 bpf_program__exit(&prog);
 373                 return -ENOMEM;
 374         }
 375
 376         pr_debug("found program %s\n", prog.section_name);
 377         obj->programs = progs;
 378         obj->nr_programs = nr_progs + 1;
 379         prog.obj = obj;
 380         progs[nr_progs] = prog;
 381         return 0;
 382 }
 383
 384 static int
 385 bpf_object__init_prog_names(struct bpf_object *obj)
 386 {
 387         Elf_Data *symbols = obj->efile.symbols;
 388         struct bpf_program *prog;
 389         size_t pi, si;
 390
 391         for (pi = 0; pi < obj->nr_programs; pi++) {
 392                 const char *name = NULL;
 393
 394                 prog = &obj->programs[pi];
 395                 if (prog->idx == obj->efile.text_shndx) {
 396                         name = ".text";
 397                         goto skip_search;
 398                 }
 399
 400                 for (si = 0; si < symbols->d_size / sizeof(GElf_Sym) && !name;
 401                      si++) {
 402                         GElf_Sym sym;
 403
 404                         if (!gelf_getsym(symbols, si, &sym))
 405                                 continue;
 406                         if (sym.st_shndx != prog->idx)
 407                                 continue;
 408                         if (GELF_ST_BIND(sym.st_info) != STB_GLOBAL)
 409                                 continue;
 410
 411                         name = elf_strptr(obj->efile.elf,
 412                                           obj->efile.strtabidx,
 413                                           sym.st_name);
 414                         if (!name) {
 415                                 pr_warning("failed to get sym name string for prog %s\n",
 416                                            prog->section_name);
 417                                 return -LIBBPF_ERRNO__LIBELF;
 418                         }
 419                 }
 420
 421                 if (!name) {
 422                         pr_warning("failed to find sym for prog %s\n",
 423                                    prog->section_name);
 424                         return -EINVAL;
 425                 }
 426 skip_search:
 427                 prog->name = strdup(name);
 428                 if (!prog->name) {
 429                         pr_warning("failed to allocate memory for prog sym %s\n",
 430                                    name);
 431                         return -ENOMEM;
 432                 }
 433         }
 434
 435         return 0;
 436 }
 437
 438 static struct bpf_object *bpf_object__new(const char *path,
 439                                           void *obj_buf,
 440                                           size_t obj_buf_sz)
 441 {
 442         struct bpf_object *obj;
 443
 444         obj = calloc(1, sizeof(struct bpf_object) + strlen(path) + 1);
 445         if (!obj) {
 446                 pr_warning("alloc memory failed for %s\n", path);
 447                 return ERR_PTR(-ENOMEM);
 448         }
 449
 450         strcpy(obj->path, path);
 451         obj->efile.fd = -1;
 452
 453         /*
 454          * Caller of this function should also calls
 455          * bpf_object__elf_finish() after data collection to return
 456          * obj_buf to user. If not, we should duplicate the buffer to
 457          * avoid user freeing them before elf finish.
 458          */
 459         obj->efile.obj_buf = obj_buf;
 460         obj->efile.obj_buf_sz = obj_buf_sz;
 461         obj->efile.maps_shndx = -1;
 462
 463         obj->loaded = false;
 464
 465         INIT_LIST_HEAD(&obj->list);
 466         list_add(&obj->list, &bpf_objects_list);
 467         return obj;
 468 }
 469
 470 static void bpf_object__elf_finish(struct bpf_object *obj)
 471 {
 472         if (!obj_elf_valid(obj))
 473                 return;
 474
 475         if (obj->efile.elf) {
 476                 elf_end(obj->efile.elf);
 477                 obj->efile.elf = NULL;
 478         }
 479         obj->efile.symbols = NULL;
 480
 481         zfree(&obj->efile.reloc);
 482         obj->efile.nr_reloc = 0;
 483         zclose(obj->efile.fd);
 484         obj->efile.obj_buf = NULL;
 485         obj->efile.obj_buf_sz = 0;
 486 }
 487
 488 static int bpf_object__elf_init(struct bpf_object *obj)
 489 {
 490         int err = 0;
 491         GElf_Ehdr *ep;
 492
 493         if (obj_elf_valid(obj)) {
 494                 pr_warning("elf init: internal error\n");
 495                 return -LIBBPF_ERRNO__LIBELF;
 496         }
 497
 498         if (obj->efile.obj_buf_sz > 0) {
 499                 /*
 500                  * obj_buf should have been validated by
 501                  * bpf_object__open_buffer().
 502                  */
 503                 obj->efile.elf = elf_memory(obj->efile.obj_buf,
 504                                             obj->efile.obj_buf_sz);
 505         } else {
 506                 obj->efile.fd = open(obj->path, O_RDONLY);
 507                 if (obj->efile.fd < 0) {
 508                         pr_warning("failed to open %s: %s\n", obj->path,
 509                                         strerror(errno));
 510                         return -errno;
 511                 }
 512
 513                 obj->efile.elf = elf_begin(obj->efile.fd,
 514                                 LIBBPF_ELF_C_READ_MMAP,
 515                                 NULL);
 516         }
 517
 518         if (!obj->efile.elf) {
 519                 pr_warning("failed to open %s as ELF file\n",
 520                                 obj->path);
 521                 err = -LIBBPF_ERRNO__LIBELF;
 522                 goto errout;
 523         }
 524
 525         if (!gelf_getehdr(obj->efile.elf, &obj->efile.ehdr)) {
 526                 pr_warning("failed to get EHDR from %s\n",
 527                                 obj->path);
 528                 err = -LIBBPF_ERRNO__FORMAT;
 529                 goto errout;
 530         }
 531         ep = &obj->efile.ehdr;
 532
 533         /* Old LLVM set e_machine to EM_NONE */
 534         if ((ep->e_type != ET_REL) || (ep->e_machine && (ep->e_machine != EM_BPF))) {
 535                 pr_warning("%s is not an eBPF object file\n",
 536                         obj->path);
 537                 err = -LIBBPF_ERRNO__FORMAT;
 538                 goto errout;
 539         }
 540
 541         return 0;
 542 errout:
 543         bpf_object__elf_finish(obj);
 544         return err;
 545 }
 546
 547 static int
 548 bpf_object__check_endianness(struct bpf_object *obj)
 549 {
 550         static unsigned int const endian = 1;
 551
 552         switch (obj->efile.ehdr.e_ident[EI_DATA]) {
 553         case ELFDATA2LSB:
 554                 /* We are big endian, BPF obj is little endian. */
 555                 if (*(unsigned char const *)&endian != 1)
 556                         goto mismatch;
 557                 break;
 558
 559         case ELFDATA2MSB:
 560                 /* We are little endian, BPF obj is big endian. */
 561                 if (*(unsigned char const *)&endian != 0)
 562                         goto mismatch;
 563                 break;
 564         default:
 565                 return -LIBBPF_ERRNO__ENDIAN;
 566         }
 567
 568         return 0;
 569
 570 mismatch:
 571         pr_warning("Error: endianness mismatch.\n");
 572         return -LIBBPF_ERRNO__ENDIAN;
 573 }
 574
 575 static int
 576 bpf_object__init_license(struct bpf_object *obj,
 577                          void *data, size_t size)
 578 {
 579         memcpy(obj->license, data,
 580                min(size, sizeof(obj->license) - 1));
 581         pr_debug("license of %s is %s\n", obj->path, obj->license);
 582         return 0;
 583 }
 584
 585 static int
 586 bpf_object__init_kversion(struct bpf_object *obj,
 587                           void *data, size_t size)
 588 {
 589         u32 kver;
 590
 591         if (size != sizeof(kver)) {
 592                 pr_warning("invalid kver section in %s\n", obj->path);
 593                 return -LIBBPF_ERRNO__FORMAT;
 594         }
 595         memcpy(&kver, data, sizeof(kver));
 596         obj->kern_version = kver;
 597         pr_debug("kernel version of %s is %x\n", obj->path,
 598                  obj->kern_version);
 599         return 0;
 600 }
 601
 602 static int compare_bpf_map(const void *_a, const void *_b)
 603 {
 604         const struct bpf_map *a = _a;
 605         const struct bpf_map *b = _b;
 606
 607         return a->offset - b->offset;
 608 }
 609
 610 static int
 611 bpf_object__init_maps(struct bpf_object *obj)
 612 {
 613         int i, map_idx, map_def_sz, nr_maps = 0;
 614         Elf_Scn *scn;
 615         Elf_Data *data;
 616         Elf_Data *symbols = obj->efile.symbols;
 617
 618         if (obj->efile.maps_shndx < 0)
 619                 return -EINVAL;
 620         if (!symbols)
 621                 return -EINVAL;
 622
 623         scn = elf_getscn(obj->efile.elf, obj->efile.maps_shndx);
 624         if (scn)
 625                 data = elf_getdata(scn, NULL);
 626         if (!scn || !data) {
 627                 pr_warning("failed to get Elf_Data from map section %d\n",
 628                            obj->efile.maps_shndx);
 629                 return -EINVAL;
 630         }
 631
 632         /*
 633          * Count number of maps. Each map has a name.
 634          * Array of maps is not supported: only the first element is
 635          * considered.
 636          *
 637          * TODO: Detect array of map and report error.
 638          */
 639         for (i = 0; i < symbols->d_size / sizeof(GElf_Sym); i++) {
 640                 GElf_Sym sym;
 641
 642                 if (!gelf_getsym(symbols, i, &sym))
 643                         continue;
 644                 if (sym.st_shndx != obj->efile.maps_shndx)
 645                         continue;
 646                 nr_maps++;
 647         }
 648
 649         /* Alloc obj->maps and fill nr_maps. */
 650         pr_debug("maps in %s: %d maps in %zd bytes\n", obj->path,
 651                  nr_maps, data->d_size);
 652
 653         if (!nr_maps)
 654                 return 0;
 655
 656         /* Assume equally sized map definitions */
 657         map_def_sz = data->d_size / nr_maps;
 658         if (!data->d_size || (data->d_size % nr_maps) != 0) {
 659                 pr_warning("unable to determine map definition size "
 660                            "section %s, %d maps in %zd bytes\n",
 661                            obj->path, nr_maps, data->d_size);
 662                 return -EINVAL;
 663         }
 664
 665         obj->maps = calloc(nr_maps, sizeof(obj->maps[0]));
 666         if (!obj->maps) {
 667                 pr_warning("alloc maps for object failed\n");
 668                 return -ENOMEM;
 669         }
 670         obj->nr_maps = nr_maps;
 671
 672         /*
 673          * fill all fd with -1 so won't close incorrect
 674          * fd (fd=0 is stdin) when failure (zclose won't close
 675          * negative fd)).
 676          */
 677         for (i = 0; i < nr_maps; i++)
 678                 obj->maps[i].fd = -1;
 679
 680         /*
 681          * Fill obj->maps using data in "maps" section.
 682          */
 683         for (i = 0, map_idx = 0; i < symbols->d_size / sizeof(GElf_Sym); i++) {
 684                 GElf_Sym sym;
 685                 const char *map_name;
 686                 struct bpf_map_def *def;
 687
 688                 if (!gelf_getsym(symbols, i, &sym))
 689                         continue;
 690                 if (sym.st_shndx != obj->efile.maps_shndx)
 691                         continue;
 692
 693                 map_name = elf_strptr(obj->efile.elf,
 694                                       obj->efile.strtabidx,
 695                                       sym.st_name);
 696                 obj->maps[map_idx].offset = sym.st_value;
 697                 if (sym.st_value + map_def_sz > data->d_size) {
 698                         pr_warning("corrupted maps section in %s: last map \"%s\" too small\n",
 699                                    obj->path, map_name);
 700                         return -EINVAL;
 701                 }
 702
 703                 obj->maps[map_idx].name = strdup(map_name);
 704                 if (!obj->maps[map_idx].name) {
 705                         pr_warning("failed to alloc map name\n");
 706                         return -ENOMEM;
 707                 }
 708                 pr_debug("map %d is \"%s\"\n", map_idx,
 709                          obj->maps[map_idx].name);
 710                 def = (struct bpf_map_def *)(data->d_buf + sym.st_value);
 711                 /*
 712                  * If the definition of the map in the object file fits in
 713                  * bpf_map_def, copy it.  Any extra fields in our version
 714                  * of bpf_map_def will default to zero as a result of the
 715                  * calloc above.
 716                  */
 717                 if (map_def_sz <= sizeof(struct bpf_map_def)) {
 718                         memcpy(&obj->maps[map_idx].def, def, map_def_sz);
 719                 } else {
 720                         /*
 721                          * Here the map structure being read is bigger than what
 722                          * we expect, truncate if the excess bits are all zero.
 723                          * If they are not zero, reject this map as
 724                          * incompatible.
 725                          */
 726                         char *b;
 727                         for (b = ((char *)def) + sizeof(struct bpf_map_def);
 728                              b < ((char *)def) + map_def_sz; b++) {
 729                                 if (*b != 0) {
 730                                         pr_warning("maps section in %s: \"%s\" "
 731                                                    "has unrecognized, non-zero "
 732                                                    "options\n",
 733                                                    obj->path, map_name);
 734                                         return -EINVAL;
 735                                 }
 736                         }
 737                         memcpy(&obj->maps[map_idx].def, def,
 738                                sizeof(struct bpf_map_def));
 739                 }
 740                 map_idx++;
 741         }
 742
 743         qsort(obj->maps, obj->nr_maps, sizeof(obj->maps[0]), compare_bpf_map);
 744         return 0;
 745 }
 746
 747 static bool section_have_execinstr(struct bpf_object *obj, int idx)
 748 {
 749         Elf_Scn *scn;
 750         GElf_Shdr sh;
 751
 752         scn = elf_getscn(obj->efile.elf, idx);
 753         if (!scn)
 754                 return false;
 755
 756         if (gelf_getshdr(scn, &sh) != &sh)
 757                 return false;
 758
 759         if (sh.sh_flags & SHF_EXECINSTR)
 760                 return true;
 761
 762         return false;
 763 }
 764
 765 static int bpf_object__elf_collect(struct bpf_object *obj)
 766 {
 767         Elf *elf = obj->efile.elf;
 768         GElf_Ehdr *ep = &obj->efile.ehdr;
 769         Elf_Scn *scn = NULL;
 770         int idx = 0, err = 0;
 771
 772         /* Elf is corrupted/truncated, avoid calling elf_strptr. */
 773         if (!elf_rawdata(elf_getscn(elf, ep->e_shstrndx), NULL)) {
 774                 pr_warning("failed to get e_shstrndx from %s\n",
 775                            obj->path);
 776                 return -LIBBPF_ERRNO__FORMAT;
 777         }
 778
 779         while ((scn = elf_nextscn(elf, scn)) != NULL) {
 780                 char *name;
 781                 GElf_Shdr sh;
 782                 Elf_Data *data;
 783
 784                 idx++;
 785                 if (gelf_getshdr(scn, &sh) != &sh) {
 786                         pr_warning("failed to get section(%d) header from %s\n",
 787                                    idx, obj->path);
 788                         err = -LIBBPF_ERRNO__FORMAT;
 789                         goto out;
 790                 }
 791
 792                 name = elf_strptr(elf, ep->e_shstrndx, sh.sh_name);
 793                 if (!name) {
 794                         pr_warning("failed to get section(%d) name from %s\n",
 795                                    idx, obj->path);
 796                         err = -LIBBPF_ERRNO__FORMAT;
 797                         goto out;
 798                 }
 799
 800                 data = elf_getdata(scn, 0);
 801                 if (!data) {
 802                         pr_warning("failed to get section(%d) data from %s(%s)\n",
 803                                    idx, name, obj->path);
 804                         err = -LIBBPF_ERRNO__FORMAT;
 805                         goto out;
 806                 }
 807                 pr_debug("section(%d) %s, size %ld, link %d, flags %lx, type=%d\n",
 808                          idx, name, (unsigned long)data->d_size,
 809                          (int)sh.sh_link, (unsigned long)sh.sh_flags,
 810                          (int)sh.sh_type);
 811
 812                 if (strcmp(name, "license") == 0)
 813                         err = bpf_object__init_license(obj,
 814                                                        data->d_buf,
 815                                                        data->d_size);
 816                 else if (strcmp(name, "version") == 0)
 817                         err = bpf_object__init_kversion(obj,
 818                                                         data->d_buf,
 819                                                         data->d_size);
 820                 else if (strcmp(name, "maps") == 0)
 821                         obj->efile.maps_shndx = idx;
 822                 else if (sh.sh_type == SHT_SYMTAB) {
 823                         if (obj->efile.symbols) {
 824                                 pr_warning("bpf: multiple SYMTAB in %s\n",
 825                                            obj->path);
 826                                 err = -LIBBPF_ERRNO__FORMAT;
 827                         } else {
 828                                 obj->efile.symbols = data;
 829                                 obj->efile.strtabidx = sh.sh_link;
 830                         }
 831                 } else if ((sh.sh_type == SHT_PROGBITS) &&
 832                            (sh.sh_flags & SHF_EXECINSTR) &&
 833                            (data->d_size > 0)) {
 834                         if (strcmp(name, ".text") == 0)
 835                                 obj->efile.text_shndx = idx;
 836                         err = bpf_object__add_program(obj, data->d_buf,
 837                                                       data->d_size, name, idx);
 838                         if (err) {
 839                                 char errmsg[STRERR_BUFSIZE];
 840
 841                                 strerror_r(-err, errmsg, sizeof(errmsg));
 842                                 pr_warning("failed to alloc program %s (%s): %s",
 843                                            name, obj->path, errmsg);
 844                         }
 845                 } else if (sh.sh_type == SHT_REL) {
 846                         void *reloc = obj->efile.reloc;
 847                         int nr_reloc = obj->efile.nr_reloc + 1;
 848                         int sec = sh.sh_info; /* points to other section */
 849
 850                         /* Only do relo for section with exec instructions */
 851                         if (!section_have_execinstr(obj, sec)) {
 852                                 pr_debug("skip relo %s(%d) for section(%d)\n",
 853                                          name, idx, sec);
 854                                 continue;
 855                         }
 856
 857                         reloc = realloc(reloc,
 858                                         sizeof(*obj->efile.reloc) * nr_reloc);
 859                         if (!reloc) {
 860                                 pr_warning("realloc failed\n");
 861                                 err = -ENOMEM;
 862                         } else {
 863                                 int n = nr_reloc - 1;
 864
 865                                 obj->efile.reloc = reloc;
 866                                 obj->efile.nr_reloc = nr_reloc;
 867
 868                                 obj->efile.reloc[n].shdr = sh;
 869                                 obj->efile.reloc[n].data = data;
 870                         }
 871                 } else {
 872                         pr_debug("skip section(%d) %s\n", idx, name);
 873                 }
 874                 if (err)
 875                         goto out;
 876         }
 877
 878         if (!obj->efile.strtabidx || obj->efile.strtabidx >= idx) {
 879                 pr_warning("Corrupted ELF file: index of strtab invalid\n");
 880                 return LIBBPF_ERRNO__FORMAT;
 881         }
 882         if (obj->efile.maps_shndx >= 0) {
 883                 err = bpf_object__init_maps(obj);
 884                 if (err)
 885                         goto out;
 886         }
 887         err = bpf_object__init_prog_names(obj);
 888 out:
 889         return err;
 890 }
 891
 892 static struct bpf_program *
 893 bpf_object__find_prog_by_idx(struct bpf_object *obj, int idx)
 894 {
 895         struct bpf_program *prog;
 896         size_t i;
 897
 898         for (i = 0; i < obj->nr_programs; i++) {
 899                 prog = &obj->programs[i];
 900                 if (prog->idx == idx)
 901                         return prog;
 902         }
 903         return NULL;
 904 }
 905
 906 static int
 907 bpf_program__collect_reloc(struct bpf_program *prog, GElf_Shdr *shdr,
 908                            Elf_Data *data, struct bpf_object *obj)
 909 {
 910         Elf_Data *symbols = obj->efile.symbols;
 911         int text_shndx = obj->efile.text_shndx;
 912         int maps_shndx = obj->efile.maps_shndx;
 913         struct bpf_map *maps = obj->maps;
 914         size_t nr_maps = obj->nr_maps;
 915         int i, nrels;
 916
 917         pr_debug("collecting relocating info for: '%s'\n",
 918                  prog->section_name);
 919         nrels = shdr->sh_size / shdr->sh_entsize;
 920
 921         prog->reloc_desc = malloc(sizeof(*prog->reloc_desc) * nrels);
 922         if (!prog->reloc_desc) {
 923                 pr_warning("failed to alloc memory in relocation\n");
 924                 return -ENOMEM;
 925         }
 926         prog->nr_reloc = nrels;
 927
 928         for (i = 0; i < nrels; i++) {
 929                 GElf_Sym sym;
 930                 GElf_Rel rel;
 931                 unsigned int insn_idx;
 932                 struct bpf_insn *insns = prog->insns;
 933                 size_t map_idx;
 934
 935                 if (!gelf_getrel(data, i, &rel)) {
 936                         pr_warning("relocation: failed to get %d reloc\n", i);
 937                         return -LIBBPF_ERRNO__FORMAT;
 938                 }
 939
 940                 if (!gelf_getsym(symbols,
 941                                  GELF_R_SYM(rel.r_info),
 942                                  &sym)) {
 943                         pr_warning("relocation: symbol %"PRIx64" not found\n",
 944                                    GELF_R_SYM(rel.r_info));
 945                         return -LIBBPF_ERRNO__FORMAT;
 946                 }
 947                 pr_debug("relo for %lld value %lld name %d\n",
 948                          (long long) (rel.r_info >> 32),
 949                          (long long) sym.st_value, sym.st_name);
 950
 951                 if (sym.st_shndx != maps_shndx && sym.st_shndx != text_shndx) {
 952                         pr_warning("Program '%s' contains non-map related relo data pointing to section %u\n",
 953                                    prog->section_name, sym.st_shndx);
 954                         return -LIBBPF_ERRNO__RELOC;
 955                 }
 956
 957                 insn_idx = rel.r_offset / sizeof(struct bpf_insn);
 958                 pr_debug("relocation: insn_idx=%u\n", insn_idx);
 959
 960                 if (insns[insn_idx].code == (BPF_JMP | BPF_CALL)) {
 961                         if (insns[insn_idx].src_reg != BPF_PSEUDO_CALL) {
 962                                 pr_warning("incorrect bpf_call opcode\n");
 963                                 return -LIBBPF_ERRNO__RELOC;
 964                         }
 965                         prog->reloc_desc[i].type = RELO_CALL;
 966                         prog->reloc_desc[i].insn_idx = insn_idx;
 967                         prog->reloc_desc[i].text_off = sym.st_value;
 968                         continue;
 969                 }
 970
 971                 if (insns[insn_idx].code != (BPF_LD | BPF_IMM | BPF_DW)) {
 972                         pr_warning("bpf: relocation: invalid relo for insns[%d].code 0x%x\n",
 973                                    insn_idx, insns[insn_idx].code);
 974                         return -LIBBPF_ERRNO__RELOC;
 975                 }
 976
 977                 /* TODO: 'maps' is sorted. We can use bsearch to make it faster. */
 978                 for (map_idx = 0; map_idx < nr_maps; map_idx++) {
 979                         if (maps[map_idx].offset == sym.st_value) {
 980                                 pr_debug("relocation: find map %zd (%s) for insn %u\n",
 981                                          map_idx, maps[map_idx].name, insn_idx);
 982                                 break;
 983                         }
 984                 }
 985
 986                 if (map_idx >= nr_maps) {
 987                         pr_warning("bpf relocation: map_idx %d large than %d\n",
 988                                    (int)map_idx, (int)nr_maps - 1);
 989                         return -LIBBPF_ERRNO__RELOC;
 990                 }
 991
 992                 prog->reloc_desc[i].type = RELO_LD64;
 993                 prog->reloc_desc[i].insn_idx = insn_idx;
 994                 prog->reloc_desc[i].map_idx = map_idx;
 995         }
 996         return 0;
 997 }
 998
 999 static int
1000 bpf_object__create_maps(struct bpf_object *obj)
1001 {
1002         unsigned int i;
1003
1004         for (i = 0; i < obj->nr_maps; i++) {
1005                 struct bpf_map_def *def = &obj->maps[i].def;
1006                 int *pfd = &obj->maps[i].fd;
1007
1008                 *pfd = bpf_create_map_name(def->type,
1009                                            obj->maps[i].name,
1010                                            def->key_size,
1011                                            def->value_size,
1012                                            def->max_entries,
1013                                            def->map_flags);
1014                 if (*pfd < 0) {
1015                         size_t j;
1016                         int err = *pfd;
1017
1018                         pr_warning("failed to create map (name: '%s'): %s\n",
1019                                    obj->maps[i].name,
1020                                    strerror(errno));
1021                         for (j = 0; j < i; j++)
1022                                 zclose(obj->maps[j].fd);
1023                         return err;
1024                 }
1025                 pr_debug("create map %s: fd=%d\n", obj->maps[i].name, *pfd);
1026         }
1027
1028         return 0;
1029 }
1030
1031 static int
1032 bpf_program__reloc_text(struct bpf_program *prog, struct bpf_object *obj,
1033                         struct reloc_desc *relo)
1034 {
1035         struct bpf_insn *insn, *new_insn;
1036         struct bpf_program *text;
1037         size_t new_cnt;
1038
1039         if (relo->type != RELO_CALL)
1040                 return -LIBBPF_ERRNO__RELOC;
1041
1042         if (prog->idx == obj->efile.text_shndx) {
1043                 pr_warning("relo in .text insn %d into off %d\n",
1044                            relo->insn_idx, relo->text_off);
1045                 return -LIBBPF_ERRNO__RELOC;
1046         }
1047
1048         if (prog->main_prog_cnt == 0) {
1049                 text = bpf_object__find_prog_by_idx(obj, obj->efile.text_shndx);
1050                 if (!text) {
1051                         pr_warning("no .text section found yet relo into text exist\n");
1052                         return -LIBBPF_ERRNO__RELOC;
1053                 }
1054                 new_cnt = prog->insns_cnt + text->insns_cnt;
1055                 new_insn = realloc(prog->insns, new_cnt * sizeof(*insn));
1056                 if (!new_insn) {
1057                         pr_warning("oom in prog realloc\n");
1058                         return -ENOMEM;
1059                 }
1060                 memcpy(new_insn + prog->insns_cnt, text->insns,
1061                        text->insns_cnt * sizeof(*insn));
1062                 prog->insns = new_insn;
1063                 prog->main_prog_cnt = prog->insns_cnt;
1064                 prog->insns_cnt = new_cnt;
1065                 pr_debug("added %zd insn from %s to prog %s\n",
1066                          text->insns_cnt, text->section_name,
1067                          prog->section_name);
1068         }
1069         insn = &prog->insns[relo->insn_idx];
1070         insn->imm += prog->main_prog_cnt - relo->insn_idx;
1071         return 0;
1072 }
1073
1074 static int
1075 bpf_program__relocate(struct bpf_program *prog, struct bpf_object *obj)
1076 {
1077         int i, err;
1078
1079         if (!prog || !prog->reloc_desc)
1080                 return 0;
1081
1082         for (i = 0; i < prog->nr_reloc; i++) {
1083                 if (prog->reloc_desc[i].type == RELO_LD64) {
1084                         struct bpf_insn *insns = prog->insns;
1085                         int insn_idx, map_idx;
1086
1087                         insn_idx = prog->reloc_desc[i].insn_idx;
1088                         map_idx = prog->reloc_desc[i].map_idx;
1089
1090                         if (insn_idx >= (int)prog->insns_cnt) {
1091                                 pr_warning("relocation out of range: '%s'\n",
1092                                            prog->section_name);
1093                                 return -LIBBPF_ERRNO__RELOC;
1094                         }
1095                         insns[insn_idx].src_reg = BPF_PSEUDO_MAP_FD;
1096                         insns[insn_idx].imm = obj->maps[map_idx].fd;
1097                 } else {
1098                         err = bpf_program__reloc_text(prog, obj,
1099                                                       &prog->reloc_desc[i]);
1100                         if (err)
1101                                 return err;
1102                 }
1103         }
1104
1105         zfree(&prog->reloc_desc);
1106         prog->nr_reloc = 0;
1107         return 0;
1108 }
1109
1110
1111 static int
1112 bpf_object__relocate(struct bpf_object *obj)
1113 {
1114         struct bpf_program *prog;
1115         size_t i;
1116         int err;
1117
1118         for (i = 0; i < obj->nr_programs; i++) {
1119                 prog = &obj->programs[i];
1120
1121                 err = bpf_program__relocate(prog, obj);
1122                 if (err) {
1123                         pr_warning("failed to relocate '%s'\n",
1124                                    prog->section_name);
1125                         return err;
1126                 }
1127         }
1128         return 0;
1129 }
1130
1131 static int bpf_object__collect_reloc(struct bpf_object *obj)
1132 {
1133         int i, err;
1134
1135         if (!obj_elf_valid(obj)) {
1136                 pr_warning("Internal error: elf object is closed\n");
1137                 return -LIBBPF_ERRNO__INTERNAL;
1138         }
1139
1140         for (i = 0; i < obj->efile.nr_reloc; i++) {
1141                 GElf_Shdr *shdr = &obj->efile.reloc[i].shdr;
1142                 Elf_Data *data = obj->efile.reloc[i].data;
1143                 int idx = shdr->sh_info;
1144                 struct bpf_program *prog;
1145
1146                 if (shdr->sh_type != SHT_REL) {
1147                         pr_warning("internal error at %d\n", __LINE__);
1148                         return -LIBBPF_ERRNO__INTERNAL;
1149                 }
1150
1151                 prog = bpf_object__find_prog_by_idx(obj, idx);
1152                 if (!prog) {
1153                         pr_warning("relocation failed: no section(%d)\n", idx);
1154                         return -LIBBPF_ERRNO__RELOC;
1155                 }
1156
1157                 err = bpf_program__collect_reloc(prog,
1158                                                  shdr, data,
1159                                                  obj);
1160                 if (err)
1161                         return err;
1162         }
1163         return 0;
1164 }
1165
1166 static int
1167 load_program(enum bpf_prog_type type, enum bpf_attach_type expected_attach_type,
1168              const char *name, struct bpf_insn *insns, int insns_cnt,
1169              char *license, u32 kern_version, int *pfd)
1170 {
1171         struct bpf_load_program_attr load_attr;
1172         char *log_buf;
1173         int ret;
1174
1175         memset(&load_attr, 0, sizeof(struct bpf_load_program_attr));
1176         load_attr.prog_type = type;
1177         load_attr.expected_attach_type = expected_attach_type;
1178         load_attr.name = name;
1179         load_attr.insns = insns;
1180         load_attr.insns_cnt = insns_cnt;
1181         load_attr.license = license;
1182         load_attr.kern_version = kern_version;
1183
1184         if (!load_attr.insns || !load_attr.insns_cnt)
1185                 return -EINVAL;
1186
1187         log_buf = malloc(BPF_LOG_BUF_SIZE);
1188         if (!log_buf)
1189                 pr_warning("Alloc log buffer for bpf loader error, continue without log\n");
1190
1191         ret = bpf_load_program_xattr(&load_attr, log_buf, BPF_LOG_BUF_SIZE);
1192
1193         if (ret >= 0) {
1194                 *pfd = ret;
1195                 ret = 0;
1196                 goto out;
1197         }
1198
1199         ret = -LIBBPF_ERRNO__LOAD;
1200         pr_warning("load bpf program failed: %s\n", strerror(errno));
1201
1202         if (log_buf && log_buf[0] != '\0') {
1203                 ret = -LIBBPF_ERRNO__VERIFY;
1204                 pr_warning("-- BEGIN DUMP LOG ---\n");
1205                 pr_warning("\n%s\n", log_buf);
1206                 pr_warning("-- END LOG --\n");
1207         } else if (load_attr.insns_cnt >= BPF_MAXINSNS) {
1208                 pr_warning("Program too large (%zu insns), at most %d insns\n",
1209                            load_attr.insns_cnt, BPF_MAXINSNS);
1210                 ret = -LIBBPF_ERRNO__PROG2BIG;
1211         } else {
1212                 /* Wrong program type? */
1213                 if (load_attr.prog_type != BPF_PROG_TYPE_KPROBE) {
1214                         int fd;
1215
1216                         load_attr.prog_type = BPF_PROG_TYPE_KPROBE;
1217                         load_attr.expected_attach_type = 0;
1218                         fd = bpf_load_program_xattr(&load_attr, NULL, 0);
1219                         if (fd >= 0) {
1220                                 close(fd);
1221                                 ret = -LIBBPF_ERRNO__PROGTYPE;
1222                                 goto out;
1223                         }
1224                 }
1225
1226                 if (log_buf)
1227                         ret = -LIBBPF_ERRNO__KVER;
1228         }
1229
1230 out:
1231         free(log_buf);
1232         return ret;
1233 }
1234
1235 static int
1236 bpf_program__load(struct bpf_program *prog,
1237                   char *license, u32 kern_version)
1238 {
1239         int err = 0, fd, i;
1240
1241         if (prog->instances.nr < 0 || !prog->instances.fds) {
1242                 if (prog->preprocessor) {
1243                         pr_warning("Internal error: can't load program '%s'\n",
1244                                    prog->section_name);
1245                         return -LIBBPF_ERRNO__INTERNAL;
1246                 }
1247
1248                 prog->instances.fds = malloc(sizeof(int));
1249                 if (!prog->instances.fds) {
1250                         pr_warning("Not enough memory for BPF fds\n");
1251                         return -ENOMEM;
1252                 }
1253                 prog->instances.nr = 1;
1254                 prog->instances.fds[0] = -1;
1255         }
1256
1257         if (!prog->preprocessor) {
1258                 if (prog->instances.nr != 1) {
1259                         pr_warning("Program '%s' is inconsistent: nr(%d) != 1\n",
1260                                    prog->section_name, prog->instances.nr);
1261                 }
1262                 err = load_program(prog->type, prog->expected_attach_type,
1263                                    prog->name, prog->insns, prog->insns_cnt,
1264                                    license, kern_version, &fd);
1265                 if (!err)
1266                         prog->instances.fds[0] = fd;
1267                 goto out;
1268         }
1269
1270         for (i = 0; i < prog->instances.nr; i++) {
1271                 struct bpf_prog_prep_result result;
1272                 bpf_program_prep_t preprocessor = prog->preprocessor;
1273
1274                 bzero(&result, sizeof(result));
1275                 err = preprocessor(prog, i, prog->insns,
1276                                    prog->insns_cnt, &result);
1277                 if (err) {
1278                         pr_warning("Preprocessing the %dth instance of program '%s' failed\n",
1279                                    i, prog->section_name);
1280                         goto out;
1281                 }
1282
1283                 if (!result.new_insn_ptr || !result.new_insn_cnt) {
1284                         pr_debug("Skip loading the %dth instance of program '%s'\n",
1285                                  i, prog->section_name);
1286                         prog->instances.fds[i] = -1;
1287                         if (result.pfd)
1288                                 *result.pfd = -1;
1289                         continue;
1290                 }
1291
1292                 err = load_program(prog->type, prog->expected_attach_type,
1293                                    prog->name, result.new_insn_ptr,
1294                                    result.new_insn_cnt,
1295                                    license, kern_version, &fd);
1296
1297                 if (err) {
1298                         pr_warning("Loading the %dth instance of program '%s' failed\n",
1299                                         i, prog->section_name);
1300                         goto out;
1301                 }
1302
1303                 if (result.pfd)
1304                         *result.pfd = fd;
1305                 prog->instances.fds[i] = fd;
1306         }
1307 out:
1308         if (err)
1309                 pr_warning("failed to load program '%s'\n",
1310                            prog->section_name);
1311         zfree(&prog->insns);
1312         prog->insns_cnt = 0;
1313         return err;
1314 }
1315
1316 static int
1317 bpf_object__load_progs(struct bpf_object *obj)
1318 {
1319         size_t i;
1320         int err;
1321
1322         for (i = 0; i < obj->nr_programs; i++) {
1323                 if (obj->programs[i].idx == obj->efile.text_shndx)
1324                         continue;
1325                 err = bpf_program__load(&obj->programs[i],
1326                                         obj->license,
1327                                         obj->kern_version);
1328                 if (err)
1329                         return err;
1330         }
1331         return 0;
1332 }
1333
1334 static int bpf_object__validate(struct bpf_object *obj)
1335 {
1336         if (obj->kern_version == 0) {
1337                 pr_warning("%s doesn't provide kernel version\n",
1338                            obj->path);
1339                 return -LIBBPF_ERRNO__KVERSION;
1340         }
1341         return 0;
1342 }
1343
1344 static struct bpf_object *
1345 __bpf_object__open(const char *path, void *obj_buf, size_t obj_buf_sz)
1346 {
1347         struct bpf_object *obj;
1348         int err;
1349
1350         if (elf_version(EV_CURRENT) == EV_NONE) {
1351                 pr_warning("failed to init libelf for %s\n", path);
1352                 return ERR_PTR(-LIBBPF_ERRNO__LIBELF);
1353         }
1354
1355         obj = bpf_object__new(path, obj_buf, obj_buf_sz);
1356         if (IS_ERR(obj))
1357                 return obj;
1358
1359         CHECK_ERR(bpf_object__elf_init(obj), err, out);
1360         CHECK_ERR(bpf_object__check_endianness(obj), err, out);
1361         CHECK_ERR(bpf_object__elf_collect(obj), err, out);
1362         CHECK_ERR(bpf_object__collect_reloc(obj), err, out);
1363         CHECK_ERR(bpf_object__validate(obj), err, out);
1364
1365         bpf_object__elf_finish(obj);
1366         return obj;
1367 out:
1368         bpf_object__close(obj);
1369         return ERR_PTR(err);
1370 }
1371
1372 struct bpf_object *bpf_object__open(const char *path)
1373 {
1374         /* param validation */
1375         if (!path)
1376                 return NULL;
1377
1378         pr_debug("loading %s\n", path);
1379
1380         return __bpf_object__open(path, NULL, 0);
1381 }
1382
1383 struct bpf_object *bpf_object__open_buffer(void *obj_buf,
1384                                            size_t obj_buf_sz,
1385                                            const char *name)
1386 {
1387         char tmp_name[64];
1388
1389         /* param validation */
1390         if (!obj_buf || obj_buf_sz <= 0)
1391                 return NULL;
1392
1393         if (!name) {
1394                 snprintf(tmp_name, sizeof(tmp_name), "%lx-%lx",
1395                          (unsigned long)obj_buf,
1396                          (unsigned long)obj_buf_sz);
1397                 tmp_name[sizeof(tmp_name) - 1] = '\0';
1398                 name = tmp_name;
1399         }
1400         pr_debug("loading object '%s' from buffer\n",
1401                  name);
1402
1403         return __bpf_object__open(name, obj_buf, obj_buf_sz);
1404 }
1405
1406 int bpf_object__unload(struct bpf_object *obj)
1407 {
1408         size_t i;
1409
1410         if (!obj)
1411                 return -EINVAL;
1412
1413         for (i = 0; i < obj->nr_maps; i++)
1414                 zclose(obj->maps[i].fd);
1415
1416         for (i = 0; i < obj->nr_programs; i++)
1417                 bpf_program__unload(&obj->programs[i]);
1418
1419         return 0;
1420 }
1421
1422 int bpf_object__load(struct bpf_object *obj)
1423 {
1424         int err;
1425
1426         if (!obj)
1427                 return -EINVAL;
1428
1429         if (obj->loaded) {
1430                 pr_warning("object should not be loaded twice\n");
1431                 return -EINVAL;
1432         }
1433
1434         obj->loaded = true;
1435
1436         CHECK_ERR(bpf_object__create_maps(obj), err, out);
1437         CHECK_ERR(bpf_object__relocate(obj), err, out);
1438         CHECK_ERR(bpf_object__load_progs(obj), err, out);
1439
1440         return 0;
1441 out:
1442         bpf_object__unload(obj);
1443         pr_warning("failed to load object '%s'\n", obj->path);
1444         return err;
1445 }
1446
1447 static int check_path(const char *path)
1448 {
1449         struct statfs st_fs;
1450         char *dname, *dir;
1451         int err = 0;
1452
1453         if (path == NULL)
1454                 return -EINVAL;
1455
1456         dname = strdup(path);
1457         if (dname == NULL)
1458                 return -ENOMEM;
1459
1460         dir = dirname(dname);
1461         if (statfs(dir, &st_fs)) {
1462                 pr_warning("failed to statfs %s: %s\n", dir, strerror(errno));
1463                 err = -errno;
1464         }
1465         free(dname);
1466
1467         if (!err && st_fs.f_type != BPF_FS_MAGIC) {
1468                 pr_warning("specified path %s is not on BPF FS\n", path);
1469                 err = -EINVAL;
1470         }
1471
1472         return err;
1473 }
1474
1475 int bpf_program__pin_instance(struct bpf_program *prog, const char *path,
1476                               int instance)
1477 {
1478         int err;
1479
1480         err = check_path(path);
1481         if (err)
1482                 return err;
1483
1484         if (prog == NULL) {
1485                 pr_warning("invalid program pointer\n");
1486                 return -EINVAL;
1487         }
1488
1489         if (instance < 0 || instance >= prog->instances.nr) {
1490                 pr_warning("invalid prog instance %d of prog %s (max %d)\n",
1491                            instance, prog->section_name, prog->instances.nr);
1492                 return -EINVAL;
1493         }
1494
1495         if (bpf_obj_pin(prog->instances.fds[instance], path)) {
1496                 pr_warning("failed to pin program: %s\n", strerror(errno));
1497                 return -errno;
1498         }
1499         pr_debug("pinned program '%s'\n", path);
1500
1501         return 0;
1502 }
1503
1504 static int make_dir(const char *path)
1505 {
1506         int err = 0;
1507
1508         if (mkdir(path, 0700) && errno != EEXIST)
1509                 err = -errno;
1510
1511         if (err)
1512                 pr_warning("failed to mkdir %s: %s\n", path, strerror(-err));
1513         return err;
1514 }
1515
1516 int bpf_program__pin(struct bpf_program *prog, const char *path)
1517 {
1518         int i, err;
1519
1520         err = check_path(path);
1521         if (err)
1522                 return err;
1523
1524         if (prog == NULL) {
1525                 pr_warning("invalid program pointer\n");
1526                 return -EINVAL;
1527         }
1528
1529         if (prog->instances.nr <= 0) {
1530                 pr_warning("no instances of prog %s to pin\n",
1531                            prog->section_name);
1532                 return -EINVAL;
1533         }
1534
1535         err = make_dir(path);
1536         if (err)
1537                 return err;
1538
1539         for (i = 0; i < prog->instances.nr; i++) {
1540                 char buf[PATH_MAX];
1541                 int len;
1542
1543                 len = snprintf(buf, PATH_MAX, "%s/%d", path, i);
1544                 if (len < 0)
1545                         return -EINVAL;
1546                 else if (len >= PATH_MAX)
1547                         return -ENAMETOOLONG;
1548
1549                 err = bpf_program__pin_instance(prog, buf, i);
1550                 if (err)
1551                         return err;
1552         }
1553
1554         return 0;
1555 }
1556
1557 int bpf_map__pin(struct bpf_map *map, const char *path)
1558 {
1559         int err;
1560
1561         err = check_path(path);
1562         if (err)
1563                 return err;
1564
1565         if (map == NULL) {
1566                 pr_warning("invalid map pointer\n");
1567                 return -EINVAL;
1568         }
1569
1570         if (bpf_obj_pin(map->fd, path)) {
1571                 pr_warning("failed to pin map: %s\n", strerror(errno));
1572                 return -errno;
1573         }
1574
1575         pr_debug("pinned map '%s'\n", path);
1576         return 0;
1577 }
1578
1579 int bpf_object__pin(struct bpf_object *obj, const char *path)
1580 {
1581         struct bpf_program *prog;
1582         struct bpf_map *map;
1583         int err;
1584
1585         if (!obj)
1586                 return -ENOENT;
1587
1588         if (!obj->loaded) {
1589                 pr_warning("object not yet loaded; load it first\n");
1590                 return -ENOENT;
1591         }
1592
1593         err = make_dir(path);
1594         if (err)
1595                 return err;
1596
1597         bpf_map__for_each(map, obj) {
1598                 char buf[PATH_MAX];
1599                 int len;
1600
1601                 len = snprintf(buf, PATH_MAX, "%s/%s", path,
1602                                bpf_map__name(map));
1603                 if (len < 0)
1604                         return -EINVAL;
1605                 else if (len >= PATH_MAX)
1606                         return -ENAMETOOLONG;
1607
1608                 err = bpf_map__pin(map, buf);
1609                 if (err)
1610                         return err;
1611         }
1612
1613         bpf_object__for_each_program(prog, obj) {
1614                 char buf[PATH_MAX];
1615                 int len;
1616
1617                 len = snprintf(buf, PATH_MAX, "%s/%s", path,
1618                                prog->section_name);
1619                 if (len < 0)
1620                         return -EINVAL;
1621                 else if (len >= PATH_MAX)
1622                         return -ENAMETOOLONG;
1623
1624                 err = bpf_program__pin(prog, buf);
1625                 if (err)
1626                         return err;
1627         }
1628
1629         return 0;
1630 }
1631
1632 void bpf_object__close(struct bpf_object *obj)
1633 {
1634         size_t i;
1635
1636         if (!obj)
1637                 return;
1638
1639         if (obj->clear_priv)
1640                 obj->clear_priv(obj, obj->priv);
1641
1642         bpf_object__elf_finish(obj);
1643         bpf_object__unload(obj);
1644
1645         for (i = 0; i < obj->nr_maps; i++) {
1646                 zfree(&obj->maps[i].name);
1647                 if (obj->maps[i].clear_priv)
1648                         obj->maps[i].clear_priv(&obj->maps[i],
1649                                                 obj->maps[i].priv);
1650                 obj->maps[i].priv = NULL;
1651                 obj->maps[i].clear_priv = NULL;
1652         }
1653         zfree(&obj->maps);
1654         obj->nr_maps = 0;
1655
1656         if (obj->programs && obj->nr_programs) {
1657                 for (i = 0; i < obj->nr_programs; i++)
1658                         bpf_program__exit(&obj->programs[i]);
1659         }
1660         zfree(&obj->programs);
1661
1662         list_del(&obj->list);
1663         free(obj);
1664 }
1665
1666 struct bpf_object *
1667 bpf_object__next(struct bpf_object *prev)
1668 {
1669         struct bpf_object *next;
1670
1671         if (!prev)
1672                 next = list_first_entry(&bpf_objects_list,
1673                                         struct bpf_object,
1674                                         list);
1675         else
1676                 next = list_next_entry(prev, list);
1677
1678         /* Empty list is noticed here so don't need checking on entry. */
1679         if (&next->list == &bpf_objects_list)
1680                 return NULL;
1681
1682         return next;
1683 }
1684
1685 const char *bpf_object__name(struct bpf_object *obj)
1686 {
1687         return obj ? obj->path : ERR_PTR(-EINVAL);
1688 }
1689
1690 unsigned int bpf_object__kversion(struct bpf_object *obj)
1691 {
1692         return obj ? obj->kern_version : 0;
1693 }
1694
1695 int bpf_object__set_priv(struct bpf_object *obj, void *priv,
1696                          bpf_object_clear_priv_t clear_priv)
1697 {
1698         if (obj->priv && obj->clear_priv)
1699                 obj->clear_priv(obj, obj->priv);
1700
1701         obj->priv = priv;
1702         obj->clear_priv = clear_priv;
1703         return 0;
1704 }
1705
1706 void *bpf_object__priv(struct bpf_object *obj)
1707 {
1708         return obj ? obj->priv : ERR_PTR(-EINVAL);
1709 }
1710
1711 struct bpf_program *
1712 bpf_program__next(struct bpf_program *prev, struct bpf_object *obj)
1713 {
1714         size_t idx;
1715
1716         if (!obj->programs)
1717                 return NULL;
1718         /* First handler */
1719         if (prev == NULL)
1720                 return &obj->programs[0];
1721
1722         if (prev->obj != obj) {
1723                 pr_warning("error: program handler doesn't match object\n");
1724                 return NULL;
1725         }
1726
1727         idx = (prev - obj->programs) + 1;
1728         if (idx >= obj->nr_programs)
1729                 return NULL;
1730         return &obj->programs[idx];
1731 }
1732
1733 int bpf_program__set_priv(struct bpf_program *prog, void *priv,
1734                           bpf_program_clear_priv_t clear_priv)
1735 {
1736         if (prog->priv && prog->clear_priv)
1737                 prog->clear_priv(prog, prog->priv);
1738
1739         prog->priv = priv;
1740         prog->clear_priv = clear_priv;
1741         return 0;
1742 }
1743
1744 void *bpf_program__priv(struct bpf_program *prog)
1745 {
1746         return prog ? prog->priv : ERR_PTR(-EINVAL);
1747 }
1748
1749 const char *bpf_program__title(struct bpf_program *prog, bool needs_copy)
1750 {
1751         const char *title;
1752
1753         title = prog->section_name;
1754         if (needs_copy) {
1755                 title = strdup(title);
1756                 if (!title) {
1757                         pr_warning("failed to strdup program title\n");
1758                         return ERR_PTR(-ENOMEM);
1759                 }
1760         }
1761
1762         return title;
1763 }
1764
1765 int bpf_program__fd(struct bpf_program *prog)
1766 {
1767         return bpf_program__nth_fd(prog, 0);
1768 }
1769
1770 int bpf_program__set_prep(struct bpf_program *prog, int nr_instances,
1771                           bpf_program_prep_t prep)
1772 {
1773         int *instances_fds;
1774
1775         if (nr_instances <= 0 || !prep)
1776                 return -EINVAL;
1777
1778         if (prog->instances.nr > 0 || prog->instances.fds) {
1779                 pr_warning("Can't set pre-processor after loading\n");
1780                 return -EINVAL;
1781         }
1782
1783         instances_fds = malloc(sizeof(int) * nr_instances);
1784         if (!instances_fds) {
1785                 pr_warning("alloc memory failed for fds\n");
1786                 return -ENOMEM;
1787         }
1788
1789         /* fill all fd with -1 */
1790         memset(instances_fds, -1, sizeof(int) * nr_instances);
1791
1792         prog->instances.nr = nr_instances;
1793         prog->instances.fds = instances_fds;
1794         prog->preprocessor = prep;
1795         return 0;
1796 }
1797
1798 int bpf_program__nth_fd(struct bpf_program *prog, int n)
1799 {
1800         int fd;
1801
1802         if (n >= prog->instances.nr || n < 0) {
1803                 pr_warning("Can't get the %dth fd from program %s: only %d instances\n",
1804                            n, prog->section_name, prog->instances.nr);
1805                 return -EINVAL;
1806         }
1807
1808         fd = prog->instances.fds[n];
1809         if (fd < 0) {
1810                 pr_warning("%dth instance of program '%s' is invalid\n",
1811                            n, prog->section_name);
1812                 return -ENOENT;
1813         }
1814
1815         return fd;
1816 }
1817
1818 void bpf_program__set_type(struct bpf_program *prog, enum bpf_prog_type type)
1819 {
1820         prog->type = type;
1821 }
1822
1823 static bool bpf_program__is_type(struct bpf_program *prog,
1824                                  enum bpf_prog_type type)
1825 {
1826         return prog ? (prog->type == type) : false;
1827 }
1828
1829 #define BPF_PROG_TYPE_FNS(NAME, TYPE)                   \
1830 int bpf_program__set_##NAME(struct bpf_program *prog)   \
1831 {                                                       \
1832         if (!prog)                                      \
1833                 return -EINVAL;                         \
1834         bpf_program__set_type(prog, TYPE);              \
1835         return 0;                                       \
1836 }                                                       \
1837                                                         \
1838 bool bpf_program__is_##NAME(struct bpf_program *prog)   \
1839 {                                                       \
1840         return bpf_program__is_type(prog, TYPE);        \
1841 }                                                       \
1842
1843 BPF_PROG_TYPE_FNS(socket_filter, BPF_PROG_TYPE_SOCKET_FILTER);
1844 BPF_PROG_TYPE_FNS(kprobe, BPF_PROG_TYPE_KPROBE);
1845 BPF_PROG_TYPE_FNS(sched_cls, BPF_PROG_TYPE_SCHED_CLS);
1846 BPF_PROG_TYPE_FNS(sched_act, BPF_PROG_TYPE_SCHED_ACT);
1847 BPF_PROG_TYPE_FNS(tracepoint, BPF_PROG_TYPE_TRACEPOINT);
1848 BPF_PROG_TYPE_FNS(xdp, BPF_PROG_TYPE_XDP);
1849 BPF_PROG_TYPE_FNS(perf_event, BPF_PROG_TYPE_PERF_EVENT);
1850
1851 static void bpf_program__set_expected_attach_type(struct bpf_program *prog,
1852                                                  enum bpf_attach_type type)
1853 {
1854         prog->expected_attach_type = type;
1855 }
1856
1857 #define BPF_PROG_SEC_FULL(string, ptype, atype) \
1858         { string, sizeof(string) - 1, ptype, atype }
1859
1860 #define BPF_PROG_SEC(string, ptype) BPF_PROG_SEC_FULL(string, ptype, 0)
1861
1862 #define BPF_SA_PROG_SEC(string, ptype) \
1863         BPF_PROG_SEC_FULL(string, BPF_PROG_TYPE_CGROUP_SOCK_ADDR, ptype)
1864
1865 static const struct {
1866         const char *sec;
1867         size_t len;
1868         enum bpf_prog_type prog_type;
1869         enum bpf_attach_type expected_attach_type;
1870 } section_names[] = {
1871         BPF_PROG_SEC("socket",          BPF_PROG_TYPE_SOCKET_FILTER),
1872         BPF_PROG_SEC("kprobe/",         BPF_PROG_TYPE_KPROBE),
1873         BPF_PROG_SEC("kretprobe/",      BPF_PROG_TYPE_KPROBE),
1874         BPF_PROG_SEC("classifier",      BPF_PROG_TYPE_SCHED_CLS),
1875         BPF_PROG_SEC("action",          BPF_PROG_TYPE_SCHED_ACT),
1876         BPF_PROG_SEC("tracepoint/",     BPF_PROG_TYPE_TRACEPOINT),
1877         BPF_PROG_SEC("xdp",             BPF_PROG_TYPE_XDP),
1878         BPF_PROG_SEC("perf_event",      BPF_PROG_TYPE_PERF_EVENT),
1879         BPF_PROG_SEC("cgroup/skb",      BPF_PROG_TYPE_CGROUP_SKB),
1880         BPF_PROG_SEC("cgroup/sock",     BPF_PROG_TYPE_CGROUP_SOCK),
1881         BPF_PROG_SEC("cgroup/dev",      BPF_PROG_TYPE_CGROUP_DEVICE),
1882         BPF_PROG_SEC("lwt_in",          BPF_PROG_TYPE_LWT_IN),
1883         BPF_PROG_SEC("lwt_out",         BPF_PROG_TYPE_LWT_OUT),
1884         BPF_PROG_SEC("lwt_xmit",        BPF_PROG_TYPE_LWT_XMIT),
1885         BPF_PROG_SEC("sockops",         BPF_PROG_TYPE_SOCK_OPS),
1886         BPF_PROG_SEC("sk_skb",          BPF_PROG_TYPE_SK_SKB),
1887         BPF_PROG_SEC("sk_msg",          BPF_PROG_TYPE_SK_MSG),
1888         BPF_SA_PROG_SEC("cgroup/bind4", BPF_CGROUP_INET4_BIND),
1889         BPF_SA_PROG_SEC("cgroup/bind6", BPF_CGROUP_INET6_BIND),
1890         BPF_SA_PROG_SEC("cgroup/connect4", BPF_CGROUP_INET4_CONNECT),
1891         BPF_SA_PROG_SEC("cgroup/connect6", BPF_CGROUP_INET6_CONNECT),
1892 };
1893
1894 #undef BPF_PROG_SEC
1895 #undef BPF_PROG_SEC_FULL
1896 #undef BPF_SA_PROG_SEC
1897
1898 static int bpf_program__identify_section(struct bpf_program *prog)
1899 {
1900         int i;
1901
1902         if (!prog->section_name)
1903                 goto err;
1904
1905         for (i = 0; i < ARRAY_SIZE(section_names); i++)
1906                 if (strncmp(prog->section_name, section_names[i].sec,
1907                             section_names[i].len) == 0)
1908                         return i;
1909
1910 err:
1911         pr_warning("failed to guess program type based on section name %s\n",
1912                    prog->section_name);
1913
1914         return -1;
1915 }
1916
1917 int bpf_map__fd(struct bpf_map *map)
1918 {
1919         return map ? map->fd : -EINVAL;
1920 }
1921
1922 const struct bpf_map_def *bpf_map__def(struct bpf_map *map)
1923 {
1924         return map ? &map->def : ERR_PTR(-EINVAL);
1925 }
1926
1927 const char *bpf_map__name(struct bpf_map *map)
1928 {
1929         return map ? map->name : NULL;
1930 }
1931
1932 int bpf_map__set_priv(struct bpf_map *map, void *priv,
1933                      bpf_map_clear_priv_t clear_priv)
1934 {
1935         if (!map)
1936                 return -EINVAL;
1937
1938         if (map->priv) {
1939                 if (map->clear_priv)
1940                         map->clear_priv(map, map->priv);
1941         }
1942
1943         map->priv = priv;
1944         map->clear_priv = clear_priv;
1945         return 0;
1946 }
1947
1948 void *bpf_map__priv(struct bpf_map *map)
1949 {
1950         return map ? map->priv : ERR_PTR(-EINVAL);
1951 }
1952
1953 struct bpf_map *
1954 bpf_map__next(struct bpf_map *prev, struct bpf_object *obj)
1955 {
1956         size_t idx;
1957         struct bpf_map *s, *e;
1958
1959         if (!obj || !obj->maps)
1960                 return NULL;
1961
1962         s = obj->maps;
1963         e = obj->maps + obj->nr_maps;
1964
1965         if (prev == NULL)
1966                 return s;
1967
1968         if ((prev < s) || (prev >= e)) {
1969                 pr_warning("error in %s: map handler doesn't belong to object\n",
1970                            __func__);
1971                 return NULL;
1972         }
1973
1974         idx = (prev - obj->maps) + 1;
1975         if (idx >= obj->nr_maps)
1976                 return NULL;
1977         return &obj->maps[idx];
1978 }
1979
1980 struct bpf_map *
1981 bpf_object__find_map_by_name(struct bpf_object *obj, const char *name)
1982 {
1983         struct bpf_map *pos;
1984
1985         bpf_map__for_each(pos, obj) {
1986                 if (pos->name && !strcmp(pos->name, name))
1987                         return pos;
1988         }
1989         return NULL;
1990 }
1991
1992 struct bpf_map *
1993 bpf_object__find_map_by_offset(struct bpf_object *obj, size_t offset)
1994 {
1995         int i;
1996
1997         for (i = 0; i < obj->nr_maps; i++) {
1998                 if (obj->maps[i].offset == offset)
1999                         return &obj->maps[i];
2000         }
2001         return ERR_PTR(-ENOENT);
2002 }
2003
2004 long libbpf_get_error(const void *ptr)
2005 {
2006         if (IS_ERR(ptr))
2007                 return PTR_ERR(ptr);
2008         return 0;
2009 }
2010
2011 int bpf_prog_load(const char *file, enum bpf_prog_type type,
2012                   struct bpf_object **pobj, int *prog_fd)
2013 {
2014         struct bpf_prog_load_attr attr;
2015
2016         memset(&attr, 0, sizeof(struct bpf_prog_load_attr));
2017         attr.file = file;
2018         attr.prog_type = type;
2019         attr.expected_attach_type = 0;
2020
2021         return bpf_prog_load_xattr(&attr, pobj, prog_fd);
2022 }
2023
2024 int bpf_prog_load_xattr(const struct bpf_prog_load_attr *attr,
2025                         struct bpf_object **pobj, int *prog_fd)
2026 {
2027         struct bpf_program *prog, *first_prog = NULL;
2028         enum bpf_attach_type expected_attach_type;
2029         enum bpf_prog_type prog_type;
2030         struct bpf_object *obj;
2031         int section_idx;
2032         int err;
2033
2034         if (!attr)
2035                 return -EINVAL;
2036
2037         obj = bpf_object__open(attr->file);
2038         if (IS_ERR(obj))
2039                 return -ENOENT;
2040
2041         bpf_object__for_each_program(prog, obj) {
2042                 /*
2043                  * If type is not specified, try to guess it based on
2044                  * section name.
2045                  */
2046                 prog_type = attr->prog_type;
2047                 expected_attach_type = attr->expected_attach_type;
2048                 if (prog_type == BPF_PROG_TYPE_UNSPEC) {
2049                         section_idx = bpf_program__identify_section(prog);
2050                         if (section_idx < 0) {
2051                                 bpf_object__close(obj);
2052                                 return -EINVAL;
2053                         }
2054                         prog_type = section_names[section_idx].prog_type;
2055                         expected_attach_type =
2056                                 section_names[section_idx].expected_attach_type;
2057                 }
2058
2059                 bpf_program__set_type(prog, prog_type);
2060                 bpf_program__set_expected_attach_type(prog,
2061                                                       expected_attach_type);
2062
2063                 if (prog->idx != obj->efile.text_shndx && !first_prog)
2064                         first_prog = prog;
2065         }
2066
2067         if (!first_prog) {
2068                 pr_warning("object file doesn't contain bpf program\n");
2069                 bpf_object__close(obj);
2070                 return -ENOENT;
2071         }
2072
2073         err = bpf_object__load(obj);
2074         if (err) {
2075                 bpf_object__close(obj);
2076                 return -EINVAL;
2077         }
2078
2079         *pobj = obj;
2080         *prog_fd = bpf_program__fd(first_prog);
2081         return 0;
2082 }