1 // SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) 2 /* Copyright (C) 2020 Facebook */ 3 4 #include <errno.h> 5 #include <linux/err.h> 6 #include <net/if.h> 7 #include <stdio.h> 8 #include <unistd.h> 9 10 #include <bpf/bpf.h> 11 #include <bpf/hashmap.h> 12 13 #include "json_writer.h" 14 #include "main.h" 15 16 static struct hashmap *link_table; 17 18 static int link_parse_fd(int *argc, char ***argv) 19 { 20 int fd; 21 22 if (is_prefix(**argv, "id")) { 23 unsigned int id; 24 char *endptr; 25 26 NEXT_ARGP(); 27 28 id = strtoul(**argv, &endptr, 0); 29 if (*endptr) { 30 p_err("can't parse %s as ID", **argv); 31 return -1; 32 } 33 NEXT_ARGP(); 34 35 fd = bpf_link_get_fd_by_id(id); 36 if (fd < 0) 37 p_err("failed to get link with ID %d: %s", id, strerror(errno)); 38 return fd; 39 } else if (is_prefix(**argv, "pinned")) { 40 char *path; 41 42 NEXT_ARGP(); 43 44 path = **argv; 45 NEXT_ARGP(); 46 47 return open_obj_pinned_any(path, BPF_OBJ_LINK); 48 } 49 50 p_err("expected 'id' or 'pinned', got: '%s'?", **argv); 51 return -1; 52 } 53 54 static void 55 show_link_header_json(struct bpf_link_info *info, json_writer_t *wtr) 56 { 57 const char *link_type_str; 58 59 jsonw_uint_field(wtr, "id", info->id); 60 link_type_str = libbpf_bpf_link_type_str(info->type); 61 if (link_type_str) 62 jsonw_string_field(wtr, "type", link_type_str); 63 else 64 jsonw_uint_field(wtr, "type", info->type); 65 66 jsonw_uint_field(json_wtr, "prog_id", info->prog_id); 67 } 68 69 static void show_link_attach_type_json(__u32 attach_type, json_writer_t *wtr) 70 { 71 const char *attach_type_str; 72 73 attach_type_str = libbpf_bpf_attach_type_str(attach_type); 74 if (attach_type_str) 75 jsonw_string_field(wtr, "attach_type", attach_type_str); 76 else 77 jsonw_uint_field(wtr, "attach_type", attach_type); 78 } 79 80 static bool is_iter_map_target(const char *target_name) 81 { 82 return strcmp(target_name, "bpf_map_elem") == 0 || 83 strcmp(target_name, "bpf_sk_storage_map") == 0; 84 } 85 86 static bool is_iter_cgroup_target(const char *target_name) 87 { 88 return strcmp(target_name, "cgroup") == 0; 89 } 90 91 static const char *cgroup_order_string(__u32 order) 92 { 93 switch (order) { 94 case BPF_CGROUP_ITER_ORDER_UNSPEC: 95 return "order_unspec"; 96 case BPF_CGROUP_ITER_SELF_ONLY: 97 return "self_only"; 98 case BPF_CGROUP_ITER_DESCENDANTS_PRE: 99 return "descendants_pre"; 100 case BPF_CGROUP_ITER_DESCENDANTS_POST: 101 return "descendants_post"; 102 case BPF_CGROUP_ITER_ANCESTORS_UP: 103 return "ancestors_up"; 104 default: /* won't happen */ 105 return "unknown"; 106 } 107 } 108 109 static bool is_iter_task_target(const char *target_name) 110 { 111 return strcmp(target_name, "task") == 0 || 112 strcmp(target_name, "task_file") == 0 || 113 strcmp(target_name, "task_vma") == 0; 114 } 115 116 static void show_iter_json(struct bpf_link_info *info, json_writer_t *wtr) 117 { 118 const char *target_name = u64_to_ptr(info->iter.target_name); 119 120 jsonw_string_field(wtr, "target_name", target_name); 121 122 if (is_iter_map_target(target_name)) 123 jsonw_uint_field(wtr, "map_id", info->iter.map.map_id); 124 else if (is_iter_task_target(target_name)) { 125 if (info->iter.task.tid) 126 jsonw_uint_field(wtr, "tid", info->iter.task.tid); 127 else if (info->iter.task.pid) 128 jsonw_uint_field(wtr, "pid", info->iter.task.pid); 129 } 130 131 if (is_iter_cgroup_target(target_name)) { 132 jsonw_lluint_field(wtr, "cgroup_id", info->iter.cgroup.cgroup_id); 133 jsonw_string_field(wtr, "order", 134 cgroup_order_string(info->iter.cgroup.order)); 135 } 136 } 137 138 static int get_prog_info(int prog_id, struct bpf_prog_info *info) 139 { 140 __u32 len = sizeof(*info); 141 int err, prog_fd; 142 143 prog_fd = bpf_prog_get_fd_by_id(prog_id); 144 if (prog_fd < 0) 145 return prog_fd; 146 147 memset(info, 0, sizeof(*info)); 148 err = bpf_prog_get_info_by_fd(prog_fd, info, &len); 149 if (err) 150 p_err("can't get prog info: %s", strerror(errno)); 151 close(prog_fd); 152 return err; 153 } 154 155 static int show_link_close_json(int fd, struct bpf_link_info *info) 156 { 157 struct bpf_prog_info prog_info; 158 const char *prog_type_str; 159 int err; 160 161 jsonw_start_object(json_wtr); 162 163 show_link_header_json(info, json_wtr); 164 165 switch (info->type) { 166 case BPF_LINK_TYPE_RAW_TRACEPOINT: 167 jsonw_string_field(json_wtr, "tp_name", 168 u64_to_ptr(info->raw_tracepoint.tp_name)); 169 break; 170 case BPF_LINK_TYPE_TRACING: 171 err = get_prog_info(info->prog_id, &prog_info); 172 if (err) 173 return err; 174 175 prog_type_str = libbpf_bpf_prog_type_str(prog_info.type); 176 /* libbpf will return NULL for variants unknown to it. */ 177 if (prog_type_str) 178 jsonw_string_field(json_wtr, "prog_type", prog_type_str); 179 else 180 jsonw_uint_field(json_wtr, "prog_type", prog_info.type); 181 182 show_link_attach_type_json(info->tracing.attach_type, 183 json_wtr); 184 break; 185 case BPF_LINK_TYPE_CGROUP: 186 jsonw_lluint_field(json_wtr, "cgroup_id", 187 info->cgroup.cgroup_id); 188 show_link_attach_type_json(info->cgroup.attach_type, json_wtr); 189 break; 190 case BPF_LINK_TYPE_ITER: 191 show_iter_json(info, json_wtr); 192 break; 193 case BPF_LINK_TYPE_NETNS: 194 jsonw_uint_field(json_wtr, "netns_ino", 195 info->netns.netns_ino); 196 show_link_attach_type_json(info->netns.attach_type, json_wtr); 197 break; 198 default: 199 break; 200 } 201 202 if (!hashmap__empty(link_table)) { 203 struct hashmap_entry *entry; 204 205 jsonw_name(json_wtr, "pinned"); 206 jsonw_start_array(json_wtr); 207 hashmap__for_each_key_entry(link_table, entry, info->id) 208 jsonw_string(json_wtr, entry->pvalue); 209 jsonw_end_array(json_wtr); 210 } 211 212 emit_obj_refs_json(refs_table, info->id, json_wtr); 213 214 jsonw_end_object(json_wtr); 215 216 return 0; 217 } 218 219 static void show_link_header_plain(struct bpf_link_info *info) 220 { 221 const char *link_type_str; 222 223 printf("%u: ", info->id); 224 link_type_str = libbpf_bpf_link_type_str(info->type); 225 if (link_type_str) 226 printf("%s ", link_type_str); 227 else 228 printf("type %u ", info->type); 229 230 printf("prog %u ", info->prog_id); 231 } 232 233 static void show_link_attach_type_plain(__u32 attach_type) 234 { 235 const char *attach_type_str; 236 237 attach_type_str = libbpf_bpf_attach_type_str(attach_type); 238 if (attach_type_str) 239 printf("attach_type %s ", attach_type_str); 240 else 241 printf("attach_type %u ", attach_type); 242 } 243 244 static void show_iter_plain(struct bpf_link_info *info) 245 { 246 const char *target_name = u64_to_ptr(info->iter.target_name); 247 248 printf("target_name %s ", target_name); 249 250 if (is_iter_map_target(target_name)) 251 printf("map_id %u ", info->iter.map.map_id); 252 else if (is_iter_task_target(target_name)) { 253 if (info->iter.task.tid) 254 printf("tid %u ", info->iter.task.tid); 255 else if (info->iter.task.pid) 256 printf("pid %u ", info->iter.task.pid); 257 } 258 259 if (is_iter_cgroup_target(target_name)) { 260 printf("cgroup_id %llu ", info->iter.cgroup.cgroup_id); 261 printf("order %s ", 262 cgroup_order_string(info->iter.cgroup.order)); 263 } 264 } 265 266 static int show_link_close_plain(int fd, struct bpf_link_info *info) 267 { 268 struct bpf_prog_info prog_info; 269 const char *prog_type_str; 270 int err; 271 272 show_link_header_plain(info); 273 274 switch (info->type) { 275 case BPF_LINK_TYPE_RAW_TRACEPOINT: 276 printf("\n\ttp '%s' ", 277 (const char *)u64_to_ptr(info->raw_tracepoint.tp_name)); 278 break; 279 case BPF_LINK_TYPE_TRACING: 280 err = get_prog_info(info->prog_id, &prog_info); 281 if (err) 282 return err; 283 284 prog_type_str = libbpf_bpf_prog_type_str(prog_info.type); 285 /* libbpf will return NULL for variants unknown to it. */ 286 if (prog_type_str) 287 printf("\n\tprog_type %s ", prog_type_str); 288 else 289 printf("\n\tprog_type %u ", prog_info.type); 290 291 show_link_attach_type_plain(info->tracing.attach_type); 292 break; 293 case BPF_LINK_TYPE_CGROUP: 294 printf("\n\tcgroup_id %zu ", (size_t)info->cgroup.cgroup_id); 295 show_link_attach_type_plain(info->cgroup.attach_type); 296 break; 297 case BPF_LINK_TYPE_ITER: 298 show_iter_plain(info); 299 break; 300 case BPF_LINK_TYPE_NETNS: 301 printf("\n\tnetns_ino %u ", info->netns.netns_ino); 302 show_link_attach_type_plain(info->netns.attach_type); 303 break; 304 default: 305 break; 306 } 307 308 if (!hashmap__empty(link_table)) { 309 struct hashmap_entry *entry; 310 311 hashmap__for_each_key_entry(link_table, entry, info->id) 312 printf("\n\tpinned %s", (char *)entry->pvalue); 313 } 314 emit_obj_refs_plain(refs_table, info->id, "\n\tpids "); 315 316 printf("\n"); 317 318 return 0; 319 } 320 321 static int do_show_link(int fd) 322 { 323 struct bpf_link_info info; 324 __u32 len = sizeof(info); 325 char buf[256]; 326 int err; 327 328 memset(&info, 0, sizeof(info)); 329 again: 330 err = bpf_link_get_info_by_fd(fd, &info, &len); 331 if (err) { 332 p_err("can't get link info: %s", 333 strerror(errno)); 334 close(fd); 335 return err; 336 } 337 if (info.type == BPF_LINK_TYPE_RAW_TRACEPOINT && 338 !info.raw_tracepoint.tp_name) { 339 info.raw_tracepoint.tp_name = (unsigned long)&buf; 340 info.raw_tracepoint.tp_name_len = sizeof(buf); 341 goto again; 342 } 343 if (info.type == BPF_LINK_TYPE_ITER && 344 !info.iter.target_name) { 345 info.iter.target_name = (unsigned long)&buf; 346 info.iter.target_name_len = sizeof(buf); 347 goto again; 348 } 349 350 if (json_output) 351 show_link_close_json(fd, &info); 352 else 353 show_link_close_plain(fd, &info); 354 355 close(fd); 356 return 0; 357 } 358 359 static int do_show(int argc, char **argv) 360 { 361 __u32 id = 0; 362 int err, fd; 363 364 if (show_pinned) { 365 link_table = hashmap__new(hash_fn_for_key_as_id, 366 equal_fn_for_key_as_id, NULL); 367 if (IS_ERR(link_table)) { 368 p_err("failed to create hashmap for pinned paths"); 369 return -1; 370 } 371 build_pinned_obj_table(link_table, BPF_OBJ_LINK); 372 } 373 build_obj_refs_table(&refs_table, BPF_OBJ_LINK); 374 375 if (argc == 2) { 376 fd = link_parse_fd(&argc, &argv); 377 if (fd < 0) 378 return fd; 379 return do_show_link(fd); 380 } 381 382 if (argc) 383 return BAD_ARG(); 384 385 if (json_output) 386 jsonw_start_array(json_wtr); 387 while (true) { 388 err = bpf_link_get_next_id(id, &id); 389 if (err) { 390 if (errno == ENOENT) 391 break; 392 p_err("can't get next link: %s%s", strerror(errno), 393 errno == EINVAL ? " -- kernel too old?" : ""); 394 break; 395 } 396 397 fd = bpf_link_get_fd_by_id(id); 398 if (fd < 0) { 399 if (errno == ENOENT) 400 continue; 401 p_err("can't get link by id (%u): %s", 402 id, strerror(errno)); 403 break; 404 } 405 406 err = do_show_link(fd); 407 if (err) 408 break; 409 } 410 if (json_output) 411 jsonw_end_array(json_wtr); 412 413 delete_obj_refs_table(refs_table); 414 415 if (show_pinned) 416 delete_pinned_obj_table(link_table); 417 418 return errno == ENOENT ? 0 : -1; 419 } 420 421 static int do_pin(int argc, char **argv) 422 { 423 int err; 424 425 err = do_pin_any(argc, argv, link_parse_fd); 426 if (!err && json_output) 427 jsonw_null(json_wtr); 428 return err; 429 } 430 431 static int do_detach(int argc, char **argv) 432 { 433 int err, fd; 434 435 if (argc != 2) { 436 p_err("link specifier is invalid or missing\n"); 437 return 1; 438 } 439 440 fd = link_parse_fd(&argc, &argv); 441 if (fd < 0) 442 return 1; 443 444 err = bpf_link_detach(fd); 445 if (err) 446 err = -errno; 447 close(fd); 448 if (err) { 449 p_err("failed link detach: %s", strerror(-err)); 450 return 1; 451 } 452 453 if (json_output) 454 jsonw_null(json_wtr); 455 456 return 0; 457 } 458 459 static int do_help(int argc, char **argv) 460 { 461 if (json_output) { 462 jsonw_null(json_wtr); 463 return 0; 464 } 465 466 fprintf(stderr, 467 "Usage: %1$s %2$s { show | list } [LINK]\n" 468 " %1$s %2$s pin LINK FILE\n" 469 " %1$s %2$s detach LINK\n" 470 " %1$s %2$s help\n" 471 "\n" 472 " " HELP_SPEC_LINK "\n" 473 " " HELP_SPEC_OPTIONS " |\n" 474 " {-f|--bpffs} | {-n|--nomount} }\n" 475 "", 476 bin_name, argv[-2]); 477 478 return 0; 479 } 480 481 static const struct cmd cmds[] = { 482 { "show", do_show }, 483 { "list", do_show }, 484 { "help", do_help }, 485 { "pin", do_pin }, 486 { "detach", do_detach }, 487 { 0 } 488 }; 489 490 int do_link(int argc, char **argv) 491 { 492 return cmd_select(cmds, argc, argv, do_help); 493 } 494