tools/bpf/bpftool/cgroup.c

   1 // SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
   2 // Copyright (C) 2017 Facebook
   3 // Author: Roman Gushchin <guro@fb.com>
   4
   5 #define _XOPEN_SOURCE 500
   6 #include <errno.h>
   7 #include <fcntl.h>
   8 #include <ftw.h>
   9 #include <mntent.h>
  10 #include <stdio.h>
  11 #include <stdlib.h>
  12 #include <string.h>
  13 #include <sys/stat.h>
  14 #include <sys/types.h>
  15 #include <unistd.h>
  16
  17 #include <bpf/bpf.h>
  18 #include <bpf/btf.h>
  19
  20 #include "main.h"
  21
  22 #define HELP_SPEC_ATTACH_FLAGS                                          \
  23         "ATTACH_FLAGS := { multi | override }"
  24
  25 #define HELP_SPEC_ATTACH_TYPES                                          \
  26         "       ATTACH_TYPE := { cgroup_inet_ingress | cgroup_inet_egress |\n" \
  27         "                        cgroup_inet_sock_create | cgroup_sock_ops |\n" \
  28         "                        cgroup_device | cgroup_inet4_bind |\n" \
  29         "                        cgroup_inet6_bind | cgroup_inet4_post_bind |\n" \
  30         "                        cgroup_inet6_post_bind | cgroup_inet4_connect |\n" \
  31         "                        cgroup_inet6_connect | cgroup_inet4_getpeername |\n" \
  32         "                        cgroup_inet6_getpeername | cgroup_inet4_getsockname |\n" \
  33         "                        cgroup_inet6_getsockname | cgroup_udp4_sendmsg |\n" \
  34         "                        cgroup_udp6_sendmsg | cgroup_udp4_recvmsg |\n" \
  35         "                        cgroup_udp6_recvmsg | cgroup_sysctl |\n" \
  36         "                        cgroup_getsockopt | cgroup_setsockopt |\n" \
  37         "                        cgroup_inet_sock_release }"
  38
  39 static unsigned int query_flags;
  40 static struct btf *btf_vmlinux;
  41 static __u32 btf_vmlinux_id;
  42
  43 static enum bpf_attach_type parse_attach_type(const char *str)
  44 {
  45         const char *attach_type_str;
  46         enum bpf_attach_type type;
  47
  48         for (type = 0; ; type++) {
  49                 attach_type_str = libbpf_bpf_attach_type_str(type);
  50                 if (!attach_type_str)
  51                         break;
  52                 if (!strcmp(str, attach_type_str))
  53                         return type;
  54         }
  55
  56         /* Also check traditionally used attach type strings. For these we keep
  57          * allowing prefixed usage.
  58          */
  59         for (type = 0; ; type++) {
  60                 attach_type_str = bpf_attach_type_input_str(type);
  61                 if (!attach_type_str)
  62                         break;
  63                 if (is_prefix(str, attach_type_str))
  64                         return type;
  65         }
  66
  67         return __MAX_BPF_ATTACH_TYPE;
  68 }
  69
  70 static void guess_vmlinux_btf_id(__u32 attach_btf_obj_id)
  71 {
  72         struct bpf_btf_info btf_info = {};
  73         __u32 btf_len = sizeof(btf_info);
  74         char name[16] = {};
  75         int err;
  76         int fd;
  77
  78         btf_info.name = ptr_to_u64(name);
  79         btf_info.name_len = sizeof(name);
  80
  81         fd = bpf_btf_get_fd_by_id(attach_btf_obj_id);
  82         if (fd < 0)
  83                 return;
  84
  85         err = bpf_btf_get_info_by_fd(fd, &btf_info, &btf_len);
  86         if (err)
  87                 goto out;
  88
  89         if (btf_info.kernel_btf && strncmp(name, "vmlinux", sizeof(name)) == 0)
  90                 btf_vmlinux_id = btf_info.id;
  91
  92 out:
  93         close(fd);
  94 }
  95
  96 static int show_bpf_prog(int id, enum bpf_attach_type attach_type,
  97                          const char *attach_flags_str,
  98                          int level)
  99 {
 100         char prog_name[MAX_PROG_FULL_NAME];
 101         const char *attach_btf_name = NULL;
 102         struct bpf_prog_info info = {};
 103         const char *attach_type_str;
 104         __u32 info_len = sizeof(info);
 105         int prog_fd;
 106
 107         prog_fd = bpf_prog_get_fd_by_id(id);
 108         if (prog_fd < 0)
 109                 return -1;
 110
 111         if (bpf_prog_get_info_by_fd(prog_fd, &info, &info_len)) {
 112                 close(prog_fd);
 113                 return -1;
 114         }
 115
 116         attach_type_str = libbpf_bpf_attach_type_str(attach_type);
 117
 118         if (btf_vmlinux) {
 119                 if (!btf_vmlinux_id)
 120                         guess_vmlinux_btf_id(info.attach_btf_obj_id);
 121
 122                 if (btf_vmlinux_id == info.attach_btf_obj_id &&
 123                     info.attach_btf_id < btf__type_cnt(btf_vmlinux)) {
 124                         const struct btf_type *t =
 125                                 btf__type_by_id(btf_vmlinux, info.attach_btf_id);
 126                         attach_btf_name =
 127                                 btf__name_by_offset(btf_vmlinux, t->name_off);
 128                 }
 129         }
 130
 131         get_prog_full_name(&info, prog_fd, prog_name, sizeof(prog_name));
 132         if (json_output) {
 133                 jsonw_start_object(json_wtr);
 134                 jsonw_uint_field(json_wtr, "id", info.id);
 135                 if (attach_type_str)
 136                         jsonw_string_field(json_wtr, "attach_type", attach_type_str);
 137                 else
 138                         jsonw_uint_field(json_wtr, "attach_type", attach_type);
 139                 if (!(query_flags & BPF_F_QUERY_EFFECTIVE))
 140                         jsonw_string_field(json_wtr, "attach_flags", attach_flags_str);
 141                 jsonw_string_field(json_wtr, "name", prog_name);
 142                 if (attach_btf_name)
 143                         jsonw_string_field(json_wtr, "attach_btf_name", attach_btf_name);
 144                 jsonw_uint_field(json_wtr, "attach_btf_obj_id", info.attach_btf_obj_id);
 145                 jsonw_uint_field(json_wtr, "attach_btf_id", info.attach_btf_id);
 146                 jsonw_end_object(json_wtr);
 147         } else {
 148                 printf("%s%-8u ", level ? "    " : "", info.id);
 149                 if (attach_type_str)
 150                         printf("%-15s", attach_type_str);
 151                 else
 152                         printf("type %-10u", attach_type);
 153                 if (query_flags & BPF_F_QUERY_EFFECTIVE)
 154                         printf(" %-15s", prog_name);
 155                 else
 156                         printf(" %-15s %-15s", attach_flags_str, prog_name);
 157                 if (attach_btf_name)
 158                         printf(" %-15s", attach_btf_name);
 159                 else if (info.attach_btf_id)
 160                         printf(" attach_btf_obj_id=%d attach_btf_id=%d",
 161                                info.attach_btf_obj_id, info.attach_btf_id);
 162                 printf("\n");
 163         }
 164
 165         close(prog_fd);
 166         return 0;
 167 }
 168
 169 static int count_attached_bpf_progs(int cgroup_fd, enum bpf_attach_type type)
 170 {
 171         __u32 prog_cnt = 0;
 172         int ret;
 173
 174         ret = bpf_prog_query(cgroup_fd, type, query_flags, NULL,
 175                              NULL, &prog_cnt);
 176         if (ret)
 177                 return -1;
 178
 179         return prog_cnt;
 180 }
 181
 182 static int cgroup_has_attached_progs(int cgroup_fd)
 183 {
 184         enum bpf_attach_type type;
 185         bool no_prog = true;
 186
 187         for (type = 0; type < __MAX_BPF_ATTACH_TYPE; type++) {
 188                 int count = count_attached_bpf_progs(cgroup_fd, type);
 189
 190                 if (count < 0 && errno != EINVAL)
 191                         return -1;
 192
 193                 if (count > 0) {
 194                         no_prog = false;
 195                         break;
 196                 }
 197         }
 198
 199         return no_prog ? 0 : 1;
 200 }
 201
 202 static int show_effective_bpf_progs(int cgroup_fd, enum bpf_attach_type type,
 203                                     int level)
 204 {
 205         LIBBPF_OPTS(bpf_prog_query_opts, p);
 206         __u32 prog_ids[1024] = {0};
 207         __u32 iter;
 208         int ret;
 209
 210         p.query_flags = query_flags;
 211         p.prog_cnt = ARRAY_SIZE(prog_ids);
 212         p.prog_ids = prog_ids;
 213
 214         ret = bpf_prog_query_opts(cgroup_fd, type, &p);
 215         if (ret)
 216                 return ret;
 217
 218         if (p.prog_cnt == 0)
 219                 return 0;
 220
 221         for (iter = 0; iter < p.prog_cnt; iter++)
 222                 show_bpf_prog(prog_ids[iter], type, NULL, level);
 223
 224         return 0;
 225 }
 226
 227 static int show_attached_bpf_progs(int cgroup_fd, enum bpf_attach_type type,
 228                                    int level)
 229 {
 230         LIBBPF_OPTS(bpf_prog_query_opts, p);
 231         __u32 prog_attach_flags[1024] = {0};
 232         const char *attach_flags_str;
 233         __u32 prog_ids[1024] = {0};
 234         char buf[32];
 235         __u32 iter;
 236         int ret;
 237
 238         p.query_flags = query_flags;
 239         p.prog_cnt = ARRAY_SIZE(prog_ids);
 240         p.prog_ids = prog_ids;
 241         p.prog_attach_flags = prog_attach_flags;
 242
 243         ret = bpf_prog_query_opts(cgroup_fd, type, &p);
 244         if (ret)
 245                 return ret;
 246
 247         if (p.prog_cnt == 0)
 248                 return 0;
 249
 250         for (iter = 0; iter < p.prog_cnt; iter++) {
 251                 __u32 attach_flags;
 252
 253                 attach_flags = prog_attach_flags[iter] ?: p.attach_flags;
 254
 255                 switch (attach_flags) {
 256                 case BPF_F_ALLOW_MULTI:
 257                         attach_flags_str = "multi";
 258                         break;
 259                 case BPF_F_ALLOW_OVERRIDE:
 260                         attach_flags_str = "override";
 261                         break;
 262                 case 0:
 263                         attach_flags_str = "";
 264                         break;
 265                 default:
 266                         snprintf(buf, sizeof(buf), "unknown(%x)", attach_flags);
 267                         attach_flags_str = buf;
 268                 }
 269
 270                 show_bpf_prog(prog_ids[iter], type,
 271                               attach_flags_str, level);
 272         }
 273
 274         return 0;
 275 }
 276
 277 static int show_bpf_progs(int cgroup_fd, enum bpf_attach_type type,
 278                           int level)
 279 {
 280         return query_flags & BPF_F_QUERY_EFFECTIVE ?
 281                show_effective_bpf_progs(cgroup_fd, type, level) :
 282                show_attached_bpf_progs(cgroup_fd, type, level);
 283 }
 284
 285 static int do_show(int argc, char **argv)
 286 {
 287         enum bpf_attach_type type;
 288         int has_attached_progs;
 289         const char *path;
 290         int cgroup_fd;
 291         int ret = -1;
 292
 293         query_flags = 0;
 294
 295         if (!REQ_ARGS(1))
 296                 return -1;
 297         path = GET_ARG();
 298
 299         while (argc) {
 300                 if (is_prefix(*argv, "effective")) {
 301                         if (query_flags & BPF_F_QUERY_EFFECTIVE) {
 302                                 p_err("duplicated argument: %s", *argv);
 303                                 return -1;
 304                         }
 305                         query_flags |= BPF_F_QUERY_EFFECTIVE;
 306                         NEXT_ARG();
 307                 } else {
 308                         p_err("expected no more arguments, 'effective', got: '%s'?",
 309                               *argv);
 310                         return -1;
 311                 }
 312         }
 313
 314         cgroup_fd = open(path, O_RDONLY);
 315         if (cgroup_fd < 0) {
 316                 p_err("can't open cgroup %s", path);
 317                 goto exit;
 318         }
 319
 320         has_attached_progs = cgroup_has_attached_progs(cgroup_fd);
 321         if (has_attached_progs < 0) {
 322                 p_err("can't query bpf programs attached to %s: %s",
 323                       path, strerror(errno));
 324                 goto exit_cgroup;
 325         } else if (!has_attached_progs) {
 326                 ret = 0;
 327                 goto exit_cgroup;
 328         }
 329
 330         if (json_output)
 331                 jsonw_start_array(json_wtr);
 332         else if (query_flags & BPF_F_QUERY_EFFECTIVE)
 333                 printf("%-8s %-15s %-15s\n", "ID", "AttachType", "Name");
 334         else
 335                 printf("%-8s %-15s %-15s %-15s\n", "ID", "AttachType",
 336                        "AttachFlags", "Name");
 337
 338         btf_vmlinux = libbpf_find_kernel_btf();
 339         for (type = 0; type < __MAX_BPF_ATTACH_TYPE; type++) {
 340                 /*
 341                  * Not all attach types may be supported, so it's expected,
 342                  * that some requests will fail.
 343                  * If we were able to get the show for at least one
 344                  * attach type, let's return 0.
 345                  */
 346                 if (show_bpf_progs(cgroup_fd, type, 0) == 0)
 347                         ret = 0;
 348         }
 349
 350         if (json_output)
 351                 jsonw_end_array(json_wtr);
 352
 353 exit_cgroup:
 354         close(cgroup_fd);
 355 exit:
 356         return ret;
 357 }
 358
 359 /*
 360  * To distinguish nftw() errors and do_show_tree_fn() errors
 361  * and avoid duplicating error messages, let's return -2
 362  * from do_show_tree_fn() in case of error.
 363  */
 364 #define NFTW_ERR                -1
 365 #define SHOW_TREE_FN_ERR        -2
 366 static int do_show_tree_fn(const char *fpath, const struct stat *sb,
 367                            int typeflag, struct FTW *ftw)
 368 {
 369         enum bpf_attach_type type;
 370         int has_attached_progs;
 371         int cgroup_fd;
 372
 373         if (typeflag != FTW_D)
 374                 return 0;
 375
 376         cgroup_fd = open(fpath, O_RDONLY);
 377         if (cgroup_fd < 0) {
 378                 p_err("can't open cgroup %s: %s", fpath, strerror(errno));
 379                 return SHOW_TREE_FN_ERR;
 380         }
 381
 382         has_attached_progs = cgroup_has_attached_progs(cgroup_fd);
 383         if (has_attached_progs < 0) {
 384                 p_err("can't query bpf programs attached to %s: %s",
 385                       fpath, strerror(errno));
 386                 close(cgroup_fd);
 387                 return SHOW_TREE_FN_ERR;
 388         } else if (!has_attached_progs) {
 389                 close(cgroup_fd);
 390                 return 0;
 391         }
 392
 393         if (json_output) {
 394                 jsonw_start_object(json_wtr);
 395                 jsonw_string_field(json_wtr, "cgroup", fpath);
 396                 jsonw_name(json_wtr, "programs");
 397                 jsonw_start_array(json_wtr);
 398         } else {
 399                 printf("%s\n", fpath);
 400         }
 401
 402         btf_vmlinux = libbpf_find_kernel_btf();
 403         for (type = 0; type < __MAX_BPF_ATTACH_TYPE; type++)
 404                 show_bpf_progs(cgroup_fd, type, ftw->level);
 405
 406         if (errno == EINVAL)
 407                 /* Last attach type does not support query.
 408                  * Do not report an error for this, especially because batch
 409                  * mode would stop processing commands.
 410                  */
 411                 errno = 0;
 412
 413         if (json_output) {
 414                 jsonw_end_array(json_wtr);
 415                 jsonw_end_object(json_wtr);
 416         }
 417
 418         close(cgroup_fd);
 419
 420         return 0;
 421 }
 422
 423 static char *find_cgroup_root(void)
 424 {
 425         struct mntent *mnt;
 426         FILE *f;
 427
 428         f = fopen("/proc/mounts", "r");
 429         if (f == NULL)
 430                 return NULL;
 431
 432         while ((mnt = getmntent(f))) {
 433                 if (strcmp(mnt->mnt_type, "cgroup2") == 0) {
 434                         fclose(f);
 435                         return strdup(mnt->mnt_dir);
 436                 }
 437         }
 438
 439         fclose(f);
 440         return NULL;
 441 }
 442
 443 static int do_show_tree(int argc, char **argv)
 444 {
 445         char *cgroup_root, *cgroup_alloced = NULL;
 446         int ret;
 447
 448         query_flags = 0;
 449
 450         if (!argc) {
 451                 cgroup_alloced = find_cgroup_root();
 452                 if (!cgroup_alloced) {
 453                         p_err("cgroup v2 isn't mounted");
 454                         return -1;
 455                 }
 456                 cgroup_root = cgroup_alloced;
 457         } else {
 458                 cgroup_root = GET_ARG();
 459
 460                 while (argc) {
 461                         if (is_prefix(*argv, "effective")) {
 462                                 if (query_flags & BPF_F_QUERY_EFFECTIVE) {
 463                                         p_err("duplicated argument: %s", *argv);
 464                                         return -1;
 465                                 }
 466                                 query_flags |= BPF_F_QUERY_EFFECTIVE;
 467                                 NEXT_ARG();
 468                         } else {
 469                                 p_err("expected no more arguments, 'effective', got: '%s'?",
 470                                       *argv);
 471                                 return -1;
 472                         }
 473                 }
 474         }
 475
 476         if (json_output)
 477                 jsonw_start_array(json_wtr);
 478         else if (query_flags & BPF_F_QUERY_EFFECTIVE)
 479                 printf("%s\n"
 480                        "%-8s %-15s %-15s\n",
 481                        "CgroupPath",
 482                        "ID", "AttachType", "Name");
 483         else
 484                 printf("%s\n"
 485                        "%-8s %-15s %-15s %-15s\n",
 486                        "CgroupPath",
 487                        "ID", "AttachType", "AttachFlags", "Name");
 488
 489         switch (nftw(cgroup_root, do_show_tree_fn, 1024, FTW_MOUNT)) {
 490         case NFTW_ERR:
 491                 p_err("can't iterate over %s: %s", cgroup_root,
 492                       strerror(errno));
 493                 ret = -1;
 494                 break;
 495         case SHOW_TREE_FN_ERR:
 496                 ret = -1;
 497                 break;
 498         default:
 499                 ret = 0;
 500         }
 501
 502         if (json_output)
 503                 jsonw_end_array(json_wtr);
 504
 505         free(cgroup_alloced);
 506
 507         return ret;
 508 }
 509
 510 static int do_attach(int argc, char **argv)
 511 {
 512         enum bpf_attach_type attach_type;
 513         int cgroup_fd, prog_fd;
 514         int attach_flags = 0;
 515         int ret = -1;
 516         int i;
 517
 518         if (argc < 4) {
 519                 p_err("too few parameters for cgroup attach");
 520                 goto exit;
 521         }
 522
 523         cgroup_fd = open(argv[0], O_RDONLY);
 524         if (cgroup_fd < 0) {
 525                 p_err("can't open cgroup %s", argv[0]);
 526                 goto exit;
 527         }
 528
 529         attach_type = parse_attach_type(argv[1]);
 530         if (attach_type == __MAX_BPF_ATTACH_TYPE) {
 531                 p_err("invalid attach type");
 532                 goto exit_cgroup;
 533         }
 534
 535         argc -= 2;
 536         argv = &argv[2];
 537         prog_fd = prog_parse_fd(&argc, &argv);
 538         if (prog_fd < 0)
 539                 goto exit_cgroup;
 540
 541         for (i = 0; i < argc; i++) {
 542                 if (is_prefix(argv[i], "multi")) {
 543                         attach_flags |= BPF_F_ALLOW_MULTI;
 544                 } else if (is_prefix(argv[i], "override")) {
 545                         attach_flags |= BPF_F_ALLOW_OVERRIDE;
 546                 } else {
 547                         p_err("unknown option: %s", argv[i]);
 548                         goto exit_cgroup;
 549                 }
 550         }
 551
 552         if (bpf_prog_attach(prog_fd, cgroup_fd, attach_type, attach_flags)) {
 553                 p_err("failed to attach program");
 554                 goto exit_prog;
 555         }
 556
 557         if (json_output)
 558                 jsonw_null(json_wtr);
 559
 560         ret = 0;
 561
 562 exit_prog:
 563         close(prog_fd);
 564 exit_cgroup:
 565         close(cgroup_fd);
 566 exit:
 567         return ret;
 568 }
 569
 570 static int do_detach(int argc, char **argv)
 571 {
 572         enum bpf_attach_type attach_type;
 573         int prog_fd, cgroup_fd;
 574         int ret = -1;
 575
 576         if (argc < 4) {
 577                 p_err("too few parameters for cgroup detach");
 578                 goto exit;
 579         }
 580
 581         cgroup_fd = open(argv[0], O_RDONLY);
 582         if (cgroup_fd < 0) {
 583                 p_err("can't open cgroup %s", argv[0]);
 584                 goto exit;
 585         }
 586
 587         attach_type = parse_attach_type(argv[1]);
 588         if (attach_type == __MAX_BPF_ATTACH_TYPE) {
 589                 p_err("invalid attach type");
 590                 goto exit_cgroup;
 591         }
 592
 593         argc -= 2;
 594         argv = &argv[2];
 595         prog_fd = prog_parse_fd(&argc, &argv);
 596         if (prog_fd < 0)
 597                 goto exit_cgroup;
 598
 599         if (bpf_prog_detach2(prog_fd, cgroup_fd, attach_type)) {
 600                 p_err("failed to detach program");
 601                 goto exit_prog;
 602         }
 603
 604         if (json_output)
 605                 jsonw_null(json_wtr);
 606
 607         ret = 0;
 608
 609 exit_prog:
 610         close(prog_fd);
 611 exit_cgroup:
 612         close(cgroup_fd);
 613 exit:
 614         return ret;
 615 }
 616
 617 static int do_help(int argc, char **argv)
 618 {
 619         if (json_output) {
 620                 jsonw_null(json_wtr);
 621                 return 0;
 622         }
 623
 624         fprintf(stderr,
 625                 "Usage: %1$s %2$s { show | list } CGROUP [**effective**]\n"
 626                 "       %1$s %2$s tree [CGROUP_ROOT] [**effective**]\n"
 627                 "       %1$s %2$s attach CGROUP ATTACH_TYPE PROG [ATTACH_FLAGS]\n"
 628                 "       %1$s %2$s detach CGROUP ATTACH_TYPE PROG\n"
 629                 "       %1$s %2$s help\n"
 630                 "\n"
 631                 HELP_SPEC_ATTACH_TYPES "\n"
 632                 "       " HELP_SPEC_ATTACH_FLAGS "\n"
 633                 "       " HELP_SPEC_PROGRAM "\n"
 634                 "       " HELP_SPEC_OPTIONS " |\n"
 635                 "                    {-f|--bpffs} }\n"
 636                 "",
 637                 bin_name, argv[-2]);
 638
 639         return 0;
 640 }
 641
 642 static const struct cmd cmds[] = {
 643         { "show",       do_show },
 644         { "list",       do_show },
 645         { "tree",       do_show_tree },
 646         { "attach",     do_attach },
 647         { "detach",     do_detach },
 648         { "help",       do_help },
 649         { 0 }
 650 };
 651
 652 int do_cgroup(int argc, char **argv)
 653 {
 654         return cmd_select(cmds, argc, argv, do_help);
 655 }