samples/bpf/bpf_load.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <stdio.h>
   3 #include <sys/types.h>
   4 #include <sys/stat.h>
   5 #include <fcntl.h>
   6 #include <libelf.h>
   7 #include <gelf.h>
   8 #include <errno.h>
   9 #include <unistd.h>
  10 #include <string.h>
  11 #include <stdbool.h>
  12 #include <stdlib.h>
  13 #include <linux/bpf.h>
  14 #include <linux/filter.h>
  15 #include <linux/perf_event.h>
  16 #include <linux/netlink.h>
  17 #include <linux/rtnetlink.h>
  18 #include <linux/types.h>
  19 #include <sys/types.h>
  20 #include <sys/socket.h>
  21 #include <sys/syscall.h>
  22 #include <sys/ioctl.h>
  23 #include <sys/mman.h>
  24 #include <poll.h>
  25 #include <ctype.h>
  26 #include <assert.h>
  27 #include <bpf/bpf.h>
  28 #include "bpf_load.h"
  29 #include "perf-sys.h"
  30
  31 #define DEBUGFS "/sys/kernel/debug/tracing/"
  32
  33 static char license[128];
  34 static int kern_version;
  35 static bool processed_sec[128];
  36 char bpf_log_buf[BPF_LOG_BUF_SIZE];
  37 int map_fd[MAX_MAPS];
  38 int prog_fd[MAX_PROGS];
  39 int event_fd[MAX_PROGS];
  40 int prog_cnt;
  41 int prog_array_fd = -1;
  42
  43 struct bpf_map_data map_data[MAX_MAPS];
  44 int map_data_count = 0;
  45
  46 static int populate_prog_array(const char *event, int prog_fd)
  47 {
  48         int ind = atoi(event), err;
  49
  50         err = bpf_map_update_elem(prog_array_fd, &ind, &prog_fd, BPF_ANY);
  51         if (err < 0) {
  52                 printf("failed to store prog_fd in prog_array\n");
  53                 return -1;
  54         }
  55         return 0;
  56 }
  57
  58 static int load_and_attach(const char *event, struct bpf_insn *prog, int size)
  59 {
  60         bool is_socket = strncmp(event, "socket", 6) == 0;
  61         bool is_kprobe = strncmp(event, "kprobe/", 7) == 0;
  62         bool is_kretprobe = strncmp(event, "kretprobe/", 10) == 0;
  63         bool is_tracepoint = strncmp(event, "tracepoint/", 11) == 0;
  64         bool is_raw_tracepoint = strncmp(event, "raw_tracepoint/", 15) == 0;
  65         bool is_xdp = strncmp(event, "xdp", 3) == 0;
  66         bool is_perf_event = strncmp(event, "perf_event", 10) == 0;
  67         bool is_cgroup_skb = strncmp(event, "cgroup/skb", 10) == 0;
  68         bool is_cgroup_sk = strncmp(event, "cgroup/sock", 11) == 0;
  69         bool is_sockops = strncmp(event, "sockops", 7) == 0;
  70         bool is_sk_skb = strncmp(event, "sk_skb", 6) == 0;
  71         bool is_sk_msg = strncmp(event, "sk_msg", 6) == 0;
  72         size_t insns_cnt = size / sizeof(struct bpf_insn);
  73         enum bpf_prog_type prog_type;
  74         char buf[256];
  75         int fd, efd, err, id;
  76         struct perf_event_attr attr = {};
  77
  78         attr.type = PERF_TYPE_TRACEPOINT;
  79         attr.sample_type = PERF_SAMPLE_RAW;
  80         attr.sample_period = 1;
  81         attr.wakeup_events = 1;
  82
  83         if (is_socket) {
  84                 prog_type = BPF_PROG_TYPE_SOCKET_FILTER;
  85         } else if (is_kprobe || is_kretprobe) {
  86                 prog_type = BPF_PROG_TYPE_KPROBE;
  87         } else if (is_tracepoint) {
  88                 prog_type = BPF_PROG_TYPE_TRACEPOINT;
  89         } else if (is_raw_tracepoint) {
  90                 prog_type = BPF_PROG_TYPE_RAW_TRACEPOINT;
  91         } else if (is_xdp) {
  92                 prog_type = BPF_PROG_TYPE_XDP;
  93         } else if (is_perf_event) {
  94                 prog_type = BPF_PROG_TYPE_PERF_EVENT;
  95         } else if (is_cgroup_skb) {
  96                 prog_type = BPF_PROG_TYPE_CGROUP_SKB;
  97         } else if (is_cgroup_sk) {
  98                 prog_type = BPF_PROG_TYPE_CGROUP_SOCK;
  99         } else if (is_sockops) {
 100                 prog_type = BPF_PROG_TYPE_SOCK_OPS;
 101         } else if (is_sk_skb) {
 102                 prog_type = BPF_PROG_TYPE_SK_SKB;
 103         } else if (is_sk_msg) {
 104                 prog_type = BPF_PROG_TYPE_SK_MSG;
 105         } else {
 106                 printf("Unknown event '%s'\n", event);
 107                 return -1;
 108         }
 109
 110         if (prog_cnt == MAX_PROGS)
 111                 return -1;
 112
 113         fd = bpf_load_program(prog_type, prog, insns_cnt, license, kern_version,
 114                               bpf_log_buf, BPF_LOG_BUF_SIZE);
 115         if (fd < 0) {
 116                 printf("bpf_load_program() err=%d\n%s", errno, bpf_log_buf);
 117                 return -1;
 118         }
 119
 120         prog_fd[prog_cnt++] = fd;
 121
 122         if (is_xdp || is_perf_event || is_cgroup_skb || is_cgroup_sk)
 123                 return 0;
 124
 125         if (is_socket || is_sockops || is_sk_skb || is_sk_msg) {
 126                 if (is_socket)
 127                         event += 6;
 128                 else
 129                         event += 7;
 130                 if (*event != '/')
 131                         return 0;
 132                 event++;
 133                 if (!isdigit(*event)) {
 134                         printf("invalid prog number\n");
 135                         return -1;
 136                 }
 137                 return populate_prog_array(event, fd);
 138         }
 139
 140         if (is_raw_tracepoint) {
 141                 efd = bpf_raw_tracepoint_open(event + 15, fd);
 142                 if (efd < 0) {
 143                         printf("tracepoint %s %s\n", event + 15, strerror(errno));
 144                         return -1;
 145                 }
 146                 event_fd[prog_cnt - 1] = efd;
 147                 return 0;
 148         }
 149
 150         if (is_kprobe || is_kretprobe) {
 151                 bool need_normal_check = true;
 152                 const char *event_prefix = "";
 153
 154                 if (is_kprobe)
 155                         event += 7;
 156                 else
 157                         event += 10;
 158
 159                 if (*event == 0) {
 160                         printf("event name cannot be empty\n");
 161                         return -1;
 162                 }
 163
 164                 if (isdigit(*event))
 165                         return populate_prog_array(event, fd);
 166
 167 #ifdef __x86_64__
 168                 if (strncmp(event, "sys_", 4) == 0) {
 169                         snprintf(buf, sizeof(buf),
 170                                  "echo '%c:__x64_%s __x64_%s' >> /sys/kernel/debug/tracing/kprobe_events",
 171                                  is_kprobe ? 'p' : 'r', event, event);
 172                         err = system(buf);
 173                         if (err >= 0) {
 174                                 need_normal_check = false;
 175                                 event_prefix = "__x64_";
 176                         }
 177                 }
 178 #endif
 179                 if (need_normal_check) {
 180                         snprintf(buf, sizeof(buf),
 181                                  "echo '%c:%s %s' >> /sys/kernel/debug/tracing/kprobe_events",
 182                                  is_kprobe ? 'p' : 'r', event, event);
 183                         err = system(buf);
 184                         if (err < 0) {
 185                                 printf("failed to create kprobe '%s' error '%s'\n",
 186                                        event, strerror(errno));
 187                                 return -1;
 188                         }
 189                 }
 190
 191                 strcpy(buf, DEBUGFS);
 192                 strcat(buf, "events/kprobes/");
 193                 strcat(buf, event_prefix);
 194                 strcat(buf, event);
 195                 strcat(buf, "/id");
 196         } else if (is_tracepoint) {
 197                 event += 11;
 198
 199                 if (*event == 0) {
 200                         printf("event name cannot be empty\n");
 201                         return -1;
 202                 }
 203                 strcpy(buf, DEBUGFS);
 204                 strcat(buf, "events/");
 205                 strcat(buf, event);
 206                 strcat(buf, "/id");
 207         }
 208
 209         efd = open(buf, O_RDONLY, 0);
 210         if (efd < 0) {
 211                 printf("failed to open event %s\n", event);
 212                 return -1;
 213         }
 214
 215         err = read(efd, buf, sizeof(buf));
 216         if (err < 0 || err >= sizeof(buf)) {
 217                 printf("read from '%s' failed '%s'\n", event, strerror(errno));
 218                 return -1;
 219         }
 220
 221         close(efd);
 222
 223         buf[err] = 0;
 224         id = atoi(buf);
 225         attr.config = id;
 226
 227         efd = sys_perf_event_open(&attr, -1/*pid*/, 0/*cpu*/, -1/*group_fd*/, 0);
 228         if (efd < 0) {
 229                 printf("event %d fd %d err %s\n", id, efd, strerror(errno));
 230                 return -1;
 231         }
 232         event_fd[prog_cnt - 1] = efd;
 233         err = ioctl(efd, PERF_EVENT_IOC_ENABLE, 0);
 234         if (err < 0) {
 235                 printf("ioctl PERF_EVENT_IOC_ENABLE failed err %s\n",
 236                        strerror(errno));
 237                 return -1;
 238         }
 239         err = ioctl(efd, PERF_EVENT_IOC_SET_BPF, fd);
 240         if (err < 0) {
 241                 printf("ioctl PERF_EVENT_IOC_SET_BPF failed err %s\n",
 242                        strerror(errno));
 243                 return -1;
 244         }
 245
 246         return 0;
 247 }
 248
 249 static int load_maps(struct bpf_map_data *maps, int nr_maps,
 250                      fixup_map_cb fixup_map)
 251 {
 252         int i, numa_node;
 253
 254         for (i = 0; i < nr_maps; i++) {
 255                 if (fixup_map) {
 256                         fixup_map(&maps[i], i);
 257                         /* Allow userspace to assign map FD prior to creation */
 258                         if (maps[i].fd != -1) {
 259                                 map_fd[i] = maps[i].fd;
 260                                 continue;
 261                         }
 262                 }
 263
 264                 numa_node = maps[i].def.map_flags & BPF_F_NUMA_NODE ?
 265                         maps[i].def.numa_node : -1;
 266
 267                 if (maps[i].def.type == BPF_MAP_TYPE_ARRAY_OF_MAPS ||
 268                     maps[i].def.type == BPF_MAP_TYPE_HASH_OF_MAPS) {
 269                         int inner_map_fd = map_fd[maps[i].def.inner_map_idx];
 270
 271                         map_fd[i] = bpf_create_map_in_map_node(maps[i].def.type,
 272                                                         maps[i].name,
 273                                                         maps[i].def.key_size,
 274                                                         inner_map_fd,
 275                                                         maps[i].def.max_entries,
 276                                                         maps[i].def.map_flags,
 277                                                         numa_node);
 278                 } else {
 279                         map_fd[i] = bpf_create_map_node(maps[i].def.type,
 280                                                         maps[i].name,
 281                                                         maps[i].def.key_size,
 282                                                         maps[i].def.value_size,
 283                                                         maps[i].def.max_entries,
 284                                                         maps[i].def.map_flags,
 285                                                         numa_node);
 286                 }
 287                 if (map_fd[i] < 0) {
 288                         printf("failed to create a map: %d %s\n",
 289                                errno, strerror(errno));
 290                         return 1;
 291                 }
 292                 maps[i].fd = map_fd[i];
 293
 294                 if (maps[i].def.type == BPF_MAP_TYPE_PROG_ARRAY)
 295                         prog_array_fd = map_fd[i];
 296         }
 297         return 0;
 298 }
 299
 300 static int get_sec(Elf *elf, int i, GElf_Ehdr *ehdr, char **shname,
 301                    GElf_Shdr *shdr, Elf_Data **data)
 302 {
 303         Elf_Scn *scn;
 304
 305         scn = elf_getscn(elf, i);
 306         if (!scn)
 307                 return 1;
 308
 309         if (gelf_getshdr(scn, shdr) != shdr)
 310                 return 2;
 311
 312         *shname = elf_strptr(elf, ehdr->e_shstrndx, shdr->sh_name);
 313         if (!*shname || !shdr->sh_size)
 314                 return 3;
 315
 316         *data = elf_getdata(scn, 0);
 317         if (!*data || elf_getdata(scn, *data) != NULL)
 318                 return 4;
 319
 320         return 0;
 321 }
 322
 323 static int parse_relo_and_apply(Elf_Data *data, Elf_Data *symbols,
 324                                 GElf_Shdr *shdr, struct bpf_insn *insn,
 325                                 struct bpf_map_data *maps, int nr_maps)
 326 {
 327         int i, nrels;
 328
 329         nrels = shdr->sh_size / shdr->sh_entsize;
 330
 331         for (i = 0; i < nrels; i++) {
 332                 GElf_Sym sym;
 333                 GElf_Rel rel;
 334                 unsigned int insn_idx;
 335                 bool match = false;
 336                 int j, map_idx;
 337
 338                 gelf_getrel(data, i, &rel);
 339
 340                 insn_idx = rel.r_offset / sizeof(struct bpf_insn);
 341
 342                 gelf_getsym(symbols, GELF_R_SYM(rel.r_info), &sym);
 343
 344                 if (insn[insn_idx].code != (BPF_LD | BPF_IMM | BPF_DW)) {
 345                         printf("invalid relo for insn[%d].code 0x%x\n",
 346                                insn_idx, insn[insn_idx].code);
 347                         return 1;
 348                 }
 349                 insn[insn_idx].src_reg = BPF_PSEUDO_MAP_FD;
 350
 351                 /* Match FD relocation against recorded map_data[] offset */
 352                 for (map_idx = 0; map_idx < nr_maps; map_idx++) {
 353                         if (maps[map_idx].elf_offset == sym.st_value) {
 354                                 match = true;
 355                                 break;
 356                         }
 357                 }
 358                 if (match) {
 359                         insn[insn_idx].imm = maps[map_idx].fd;
 360                 } else {
 361                         printf("invalid relo for insn[%d] no map_data match\n",
 362                                insn_idx);
 363                         return 1;
 364                 }
 365         }
 366
 367         return 0;
 368 }
 369
 370 static int cmp_symbols(const void *l, const void *r)
 371 {
 372         const GElf_Sym *lsym = (const GElf_Sym *)l;
 373         const GElf_Sym *rsym = (const GElf_Sym *)r;
 374
 375         if (lsym->st_value < rsym->st_value)
 376                 return -1;
 377         else if (lsym->st_value > rsym->st_value)
 378                 return 1;
 379         else
 380                 return 0;
 381 }
 382
 383 static int load_elf_maps_section(struct bpf_map_data *maps, int maps_shndx,
 384                                  Elf *elf, Elf_Data *symbols, int strtabidx)
 385 {
 386         int map_sz_elf, map_sz_copy;
 387         bool validate_zero = false;
 388         Elf_Data *data_maps;
 389         int i, nr_maps;
 390         GElf_Sym *sym;
 391         Elf_Scn *scn;
 392         int copy_sz;
 393
 394         if (maps_shndx < 0)
 395                 return -EINVAL;
 396         if (!symbols)
 397                 return -EINVAL;
 398
 399         /* Get data for maps section via elf index */
 400         scn = elf_getscn(elf, maps_shndx);
 401         if (scn)
 402                 data_maps = elf_getdata(scn, NULL);
 403         if (!scn || !data_maps) {
 404                 printf("Failed to get Elf_Data from maps section %d\n",
 405                        maps_shndx);
 406                 return -EINVAL;
 407         }
 408
 409         /* For each map get corrosponding symbol table entry */
 410         sym = calloc(MAX_MAPS+1, sizeof(GElf_Sym));
 411         for (i = 0, nr_maps = 0; i < symbols->d_size / sizeof(GElf_Sym); i++) {
 412                 assert(nr_maps < MAX_MAPS+1);
 413                 if (!gelf_getsym(symbols, i, &sym[nr_maps]))
 414                         continue;
 415                 if (sym[nr_maps].st_shndx != maps_shndx)
 416                         continue;
 417                 /* Only increment iif maps section */
 418                 nr_maps++;
 419         }
 420
 421         /* Align to map_fd[] order, via sort on offset in sym.st_value */
 422         qsort(sym, nr_maps, sizeof(GElf_Sym), cmp_symbols);
 423
 424         /* Keeping compatible with ELF maps section changes
 425          * ------------------------------------------------
 426          * The program size of struct bpf_load_map_def is known by loader
 427          * code, but struct stored in ELF file can be different.
 428          *
 429          * Unfortunately sym[i].st_size is zero.  To calculate the
 430          * struct size stored in the ELF file, assume all struct have
 431          * the same size, and simply divide with number of map
 432          * symbols.
 433          */
 434         map_sz_elf = data_maps->d_size / nr_maps;
 435         map_sz_copy = sizeof(struct bpf_load_map_def);
 436         if (map_sz_elf < map_sz_copy) {
 437                 /*
 438                  * Backward compat, loading older ELF file with
 439                  * smaller struct, keeping remaining bytes zero.
 440                  */
 441                 map_sz_copy = map_sz_elf;
 442         } else if (map_sz_elf > map_sz_copy) {
 443                 /*
 444                  * Forward compat, loading newer ELF file with larger
 445                  * struct with unknown features. Assume zero means
 446                  * feature not used.  Thus, validate rest of struct
 447                  * data is zero.
 448                  */
 449                 validate_zero = true;
 450         }
 451
 452         /* Memcpy relevant part of ELF maps data to loader maps */
 453         for (i = 0; i < nr_maps; i++) {
 454                 struct bpf_load_map_def *def;
 455                 unsigned char *addr, *end;
 456                 const char *map_name;
 457                 size_t offset;
 458
 459                 map_name = elf_strptr(elf, strtabidx, sym[i].st_name);
 460                 maps[i].name = strdup(map_name);
 461                 if (!maps[i].name) {
 462                         printf("strdup(%s): %s(%d)\n", map_name,
 463                                strerror(errno), errno);
 464                         free(sym);
 465                         return -errno;
 466                 }
 467
 468                 /* Symbol value is offset into ELF maps section data area */
 469                 offset = sym[i].st_value;
 470                 def = (struct bpf_load_map_def *)(data_maps->d_buf + offset);
 471                 maps[i].elf_offset = offset;
 472                 memset(&maps[i].def, 0, sizeof(struct bpf_load_map_def));
 473                 memcpy(&maps[i].def, def, map_sz_copy);
 474
 475                 /* Verify no newer features were requested */
 476                 if (validate_zero) {
 477                         addr = (unsigned char*) def + map_sz_copy;
 478                         end  = (unsigned char*) def + map_sz_elf;
 479                         for (; addr < end; addr++) {
 480                                 if (*addr != 0) {
 481                                         free(sym);
 482                                         return -EFBIG;
 483                                 }
 484                         }
 485                 }
 486         }
 487
 488         free(sym);
 489         return nr_maps;
 490 }
 491
 492 static int do_load_bpf_file(const char *path, fixup_map_cb fixup_map)
 493 {
 494         int fd, i, ret, maps_shndx = -1, strtabidx = -1;
 495         Elf *elf;
 496         GElf_Ehdr ehdr;
 497         GElf_Shdr shdr, shdr_prog;
 498         Elf_Data *data, *data_prog, *data_maps = NULL, *symbols = NULL;
 499         char *shname, *shname_prog;
 500         int nr_maps = 0;
 501
 502         /* reset global variables */
 503         kern_version = 0;
 504         memset(license, 0, sizeof(license));
 505         memset(processed_sec, 0, sizeof(processed_sec));
 506
 507         if (elf_version(EV_CURRENT) == EV_NONE)
 508                 return 1;
 509
 510         fd = open(path, O_RDONLY, 0);
 511         if (fd < 0)
 512                 return 1;
 513
 514         elf = elf_begin(fd, ELF_C_READ, NULL);
 515
 516         if (!elf)
 517                 return 1;
 518
 519         if (gelf_getehdr(elf, &ehdr) != &ehdr)
 520                 return 1;
 521
 522         /* clear all kprobes */
 523         i = system("echo \"\" > /sys/kernel/debug/tracing/kprobe_events");
 524
 525         /* scan over all elf sections to get license and map info */
 526         for (i = 1; i < ehdr.e_shnum; i++) {
 527
 528                 if (get_sec(elf, i, &ehdr, &shname, &shdr, &data))
 529                         continue;
 530
 531                 if (0) /* helpful for llvm debugging */
 532                         printf("section %d:%s data %p size %zd link %d flags %d\n",
 533                                i, shname, data->d_buf, data->d_size,
 534                                shdr.sh_link, (int) shdr.sh_flags);
 535
 536                 if (strcmp(shname, "license") == 0) {
 537                         processed_sec[i] = true;
 538                         memcpy(license, data->d_buf, data->d_size);
 539                 } else if (strcmp(shname, "version") == 0) {
 540                         processed_sec[i] = true;
 541                         if (data->d_size != sizeof(int)) {
 542                                 printf("invalid size of version section %zd\n",
 543                                        data->d_size);
 544                                 return 1;
 545                         }
 546                         memcpy(&kern_version, data->d_buf, sizeof(int));
 547                 } else if (strcmp(shname, "maps") == 0) {
 548                         int j;
 549
 550                         maps_shndx = i;
 551                         data_maps = data;
 552                         for (j = 0; j < MAX_MAPS; j++)
 553                                 map_data[j].fd = -1;
 554                 } else if (shdr.sh_type == SHT_SYMTAB) {
 555                         strtabidx = shdr.sh_link;
 556                         symbols = data;
 557                 }
 558         }
 559
 560         ret = 1;
 561
 562         if (!symbols) {
 563                 printf("missing SHT_SYMTAB section\n");
 564                 goto done;
 565         }
 566
 567         if (data_maps) {
 568                 nr_maps = load_elf_maps_section(map_data, maps_shndx,
 569                                                 elf, symbols, strtabidx);
 570                 if (nr_maps < 0) {
 571                         printf("Error: Failed loading ELF maps (errno:%d):%s\n",
 572                                nr_maps, strerror(-nr_maps));
 573                         goto done;
 574                 }
 575                 if (load_maps(map_data, nr_maps, fixup_map))
 576                         goto done;
 577                 map_data_count = nr_maps;
 578
 579                 processed_sec[maps_shndx] = true;
 580         }
 581
 582         /* process all relo sections, and rewrite bpf insns for maps */
 583         for (i = 1; i < ehdr.e_shnum; i++) {
 584                 if (processed_sec[i])
 585                         continue;
 586
 587                 if (get_sec(elf, i, &ehdr, &shname, &shdr, &data))
 588                         continue;
 589
 590                 if (shdr.sh_type == SHT_REL) {
 591                         struct bpf_insn *insns;
 592
 593                         /* locate prog sec that need map fixup (relocations) */
 594                         if (get_sec(elf, shdr.sh_info, &ehdr, &shname_prog,
 595                                     &shdr_prog, &data_prog))
 596                                 continue;
 597
 598                         if (shdr_prog.sh_type != SHT_PROGBITS ||
 599                             !(shdr_prog.sh_flags & SHF_EXECINSTR))
 600                                 continue;
 601
 602                         insns = (struct bpf_insn *) data_prog->d_buf;
 603                         processed_sec[i] = true; /* relo section */
 604
 605                         if (parse_relo_and_apply(data, symbols, &shdr, insns,
 606                                                  map_data, nr_maps))
 607                                 continue;
 608                 }
 609         }
 610
 611         /* load programs */
 612         for (i = 1; i < ehdr.e_shnum; i++) {
 613
 614                 if (processed_sec[i])
 615                         continue;
 616
 617                 if (get_sec(elf, i, &ehdr, &shname, &shdr, &data))
 618                         continue;
 619
 620                 if (memcmp(shname, "kprobe/", 7) == 0 ||
 621                     memcmp(shname, "kretprobe/", 10) == 0 ||
 622                     memcmp(shname, "tracepoint/", 11) == 0 ||
 623                     memcmp(shname, "raw_tracepoint/", 15) == 0 ||
 624                     memcmp(shname, "xdp", 3) == 0 ||
 625                     memcmp(shname, "perf_event", 10) == 0 ||
 626                     memcmp(shname, "socket", 6) == 0 ||
 627                     memcmp(shname, "cgroup/", 7) == 0 ||
 628                     memcmp(shname, "sockops", 7) == 0 ||
 629                     memcmp(shname, "sk_skb", 6) == 0 ||
 630                     memcmp(shname, "sk_msg", 6) == 0) {
 631                         ret = load_and_attach(shname, data->d_buf,
 632                                               data->d_size);
 633                         if (ret != 0)
 634                                 goto done;
 635                 }
 636         }
 637
 638 done:
 639         close(fd);
 640         return ret;
 641 }
 642
 643 int load_bpf_file(char *path)
 644 {
 645         return do_load_bpf_file(path, NULL);
 646 }
 647
 648 int load_bpf_file_fixup_map(const char *path, fixup_map_cb fixup_map)
 649 {
 650         return do_load_bpf_file(path, fixup_map);
 651 }
 652
 653 void read_trace_pipe(void)
 654 {
 655         int trace_fd;
 656
 657         trace_fd = open(DEBUGFS "trace_pipe", O_RDONLY, 0);
 658         if (trace_fd < 0)
 659                 return;
 660
 661         while (1) {
 662                 static char buf[4096];
 663                 ssize_t sz;
 664
 665                 sz = read(trace_fd, buf, sizeof(buf));
 666                 if (sz > 0) {
 667                         buf[sz] = 0;
 668                         puts(buf);
 669                 }
 670         }
 671 }