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
  19 #include "main.h"
  20
  21 #define HELP_SPEC_ATTACH_FLAGS                                          \
  22         "ATTACH_FLAGS := { multi | override }"
  23
  24 #define HELP_SPEC_ATTACH_TYPES                                                 \
  25         "       ATTACH_TYPE := { ingress | egress | sock_create |\n"           \
  26         "                        sock_ops | device | bind4 | bind6 |\n"        \
  27         "                        post_bind4 | post_bind6 | connect4 |\n"       \
  28         "                        connect6 | getpeername4 | getpeername6 |\n"   \
  29         "                        getsockname4 | getsockname6 | sendmsg4 |\n"   \
  30         "                        sendmsg6 | recvmsg4 | recvmsg6 |\n"           \
  31         "                        sysctl | getsockopt | setsockopt }"
  32
  33 static unsigned int query_flags;
  34
  35 static enum bpf_attach_type parse_attach_type(const char *str)
  36 {
  37         enum bpf_attach_type type;
  38
  39         for (type = 0; type < __MAX_BPF_ATTACH_TYPE; type++) {
  40                 if (attach_type_name[type] &&
  41                     is_prefix(str, attach_type_name[type]))
  42                         return type;
  43         }
  44
  45         return __MAX_BPF_ATTACH_TYPE;
  46 }
  47
  48 static int show_bpf_prog(int id, enum bpf_attach_type attach_type,
  49                          const char *attach_flags_str,
  50                          int level)
  51 {
  52         struct bpf_prog_info info = {};
  53         __u32 info_len = sizeof(info);
  54         int prog_fd;
  55
  56         prog_fd = bpf_prog_get_fd_by_id(id);
  57         if (prog_fd < 0)
  58                 return -1;
  59
  60         if (bpf_obj_get_info_by_fd(prog_fd, &info, &info_len)) {
  61                 close(prog_fd);
  62                 return -1;
  63         }
  64
  65         if (json_output) {
  66                 jsonw_start_object(json_wtr);
  67                 jsonw_uint_field(json_wtr, "id", info.id);
  68                 if (attach_type < ARRAY_SIZE(attach_type_name))
  69                         jsonw_string_field(json_wtr, "attach_type",
  70                                            attach_type_name[attach_type]);
  71                 else
  72                         jsonw_uint_field(json_wtr, "attach_type", attach_type);
  73                 jsonw_string_field(json_wtr, "attach_flags",
  74                                    attach_flags_str);
  75                 jsonw_string_field(json_wtr, "name", info.name);
  76                 jsonw_end_object(json_wtr);
  77         } else {
  78                 printf("%s%-8u ", level ? "    " : "", info.id);
  79                 if (attach_type < ARRAY_SIZE(attach_type_name))
  80                         printf("%-15s", attach_type_name[attach_type]);
  81                 else
  82                         printf("type %-10u", attach_type);
  83                 printf(" %-15s %-15s\n", attach_flags_str, info.name);
  84         }
  85
  86         close(prog_fd);
  87         return 0;
  88 }
  89
  90 static int count_attached_bpf_progs(int cgroup_fd, enum bpf_attach_type type)
  91 {
  92         __u32 prog_cnt = 0;
  93         int ret;
  94
  95         ret = bpf_prog_query(cgroup_fd, type, query_flags, NULL,
  96                              NULL, &prog_cnt);
  97         if (ret)
  98                 return -1;
  99
 100         return prog_cnt;
 101 }
 102
 103 static int cgroup_has_attached_progs(int cgroup_fd)
 104 {
 105         enum bpf_attach_type type;
 106         bool no_prog = true;
 107
 108         for (type = 0; type < __MAX_BPF_ATTACH_TYPE; type++) {
 109                 int count = count_attached_bpf_progs(cgroup_fd, type);
 110
 111                 if (count < 0 && errno != EINVAL)
 112                         return -1;
 113
 114                 if (count > 0) {
 115                         no_prog = false;
 116                         break;
 117                 }
 118         }
 119
 120         return no_prog ? 0 : 1;
 121 }
 122 static int show_attached_bpf_progs(int cgroup_fd, enum bpf_attach_type type,
 123                                    int level)
 124 {
 125         const char *attach_flags_str;
 126         __u32 prog_ids[1024] = {0};
 127         __u32 prog_cnt, iter;
 128         __u32 attach_flags;
 129         char buf[32];
 130         int ret;
 131
 132         prog_cnt = ARRAY_SIZE(prog_ids);
 133         ret = bpf_prog_query(cgroup_fd, type, query_flags, &attach_flags,
 134                              prog_ids, &prog_cnt);
 135         if (ret)
 136                 return ret;
 137
 138         if (prog_cnt == 0)
 139                 return 0;
 140
 141         switch (attach_flags) {
 142         case BPF_F_ALLOW_MULTI:
 143                 attach_flags_str = "multi";
 144                 break;
 145         case BPF_F_ALLOW_OVERRIDE:
 146                 attach_flags_str = "override";
 147                 break;
 148         case 0:
 149                 attach_flags_str = "";
 150                 break;
 151         default:
 152                 snprintf(buf, sizeof(buf), "unknown(%x)", attach_flags);
 153                 attach_flags_str = buf;
 154         }
 155
 156         for (iter = 0; iter < prog_cnt; iter++)
 157                 show_bpf_prog(prog_ids[iter], type,
 158                               attach_flags_str, level);
 159
 160         return 0;
 161 }
 162
 163 static int do_show(int argc, char **argv)
 164 {
 165         enum bpf_attach_type type;
 166         int has_attached_progs;
 167         const char *path;
 168         int cgroup_fd;
 169         int ret = -1;
 170
 171         query_flags = 0;
 172
 173         if (!REQ_ARGS(1))
 174                 return -1;
 175         path = GET_ARG();
 176
 177         while (argc) {
 178                 if (is_prefix(*argv, "effective")) {
 179                         if (query_flags & BPF_F_QUERY_EFFECTIVE) {
 180                                 p_err("duplicated argument: %s", *argv);
 181                                 return -1;
 182                         }
 183                         query_flags |= BPF_F_QUERY_EFFECTIVE;
 184                         NEXT_ARG();
 185                 } else {
 186                         p_err("expected no more arguments, 'effective', got: '%s'?",
 187                               *argv);
 188                         return -1;
 189                 }
 190         }
 191
 192         cgroup_fd = open(path, O_RDONLY);
 193         if (cgroup_fd < 0) {
 194                 p_err("can't open cgroup %s", path);
 195                 goto exit;
 196         }
 197
 198         has_attached_progs = cgroup_has_attached_progs(cgroup_fd);
 199         if (has_attached_progs < 0) {
 200                 p_err("can't query bpf programs attached to %s: %s",
 201                       path, strerror(errno));
 202                 goto exit_cgroup;
 203         } else if (!has_attached_progs) {
 204                 ret = 0;
 205                 goto exit_cgroup;
 206         }
 207
 208         if (json_output)
 209                 jsonw_start_array(json_wtr);
 210         else
 211                 printf("%-8s %-15s %-15s %-15s\n", "ID", "AttachType",
 212                        "AttachFlags", "Name");
 213
 214         for (type = 0; type < __MAX_BPF_ATTACH_TYPE; type++) {
 215                 /*
 216                  * Not all attach types may be supported, so it's expected,
 217                  * that some requests will fail.
 218                  * If we were able to get the show for at least one
 219                  * attach type, let's return 0.
 220                  */
 221                 if (show_attached_bpf_progs(cgroup_fd, type, 0) == 0)
 222                         ret = 0;
 223         }
 224
 225         if (json_output)
 226                 jsonw_end_array(json_wtr);
 227
 228 exit_cgroup:
 229         close(cgroup_fd);
 230 exit:
 231         return ret;
 232 }
 233
 234 /*
 235  * To distinguish nftw() errors and do_show_tree_fn() errors
 236  * and avoid duplicating error messages, let's return -2
 237  * from do_show_tree_fn() in case of error.
 238  */
 239 #define NFTW_ERR                -1
 240 #define SHOW_TREE_FN_ERR        -2
 241 static int do_show_tree_fn(const char *fpath, const struct stat *sb,
 242                            int typeflag, struct FTW *ftw)
 243 {
 244         enum bpf_attach_type type;
 245         int has_attached_progs;
 246         int cgroup_fd;
 247
 248         if (typeflag != FTW_D)
 249                 return 0;
 250
 251         cgroup_fd = open(fpath, O_RDONLY);
 252         if (cgroup_fd < 0) {
 253                 p_err("can't open cgroup %s: %s", fpath, strerror(errno));
 254                 return SHOW_TREE_FN_ERR;
 255         }
 256
 257         has_attached_progs = cgroup_has_attached_progs(cgroup_fd);
 258         if (has_attached_progs < 0) {
 259                 p_err("can't query bpf programs attached to %s: %s",
 260                       fpath, strerror(errno));
 261                 close(cgroup_fd);
 262                 return SHOW_TREE_FN_ERR;
 263         } else if (!has_attached_progs) {
 264                 close(cgroup_fd);
 265                 return 0;
 266         }
 267
 268         if (json_output) {
 269                 jsonw_start_object(json_wtr);
 270                 jsonw_string_field(json_wtr, "cgroup", fpath);
 271                 jsonw_name(json_wtr, "programs");
 272                 jsonw_start_array(json_wtr);
 273         } else {
 274                 printf("%s\n", fpath);
 275         }
 276
 277         for (type = 0; type < __MAX_BPF_ATTACH_TYPE; type++)
 278                 show_attached_bpf_progs(cgroup_fd, type, ftw->level);
 279
 280         if (errno == EINVAL)
 281                 /* Last attach type does not support query.
 282                  * Do not report an error for this, especially because batch
 283                  * mode would stop processing commands.
 284                  */
 285                 errno = 0;
 286
 287         if (json_output) {
 288                 jsonw_end_array(json_wtr);
 289                 jsonw_end_object(json_wtr);
 290         }
 291
 292         close(cgroup_fd);
 293
 294         return 0;
 295 }
 296
 297 static char *find_cgroup_root(void)
 298 {
 299         struct mntent *mnt;
 300         FILE *f;
 301
 302         f = fopen("/proc/mounts", "r");
 303         if (f == NULL)
 304                 return NULL;
 305
 306         while ((mnt = getmntent(f))) {
 307                 if (strcmp(mnt->mnt_type, "cgroup2") == 0) {
 308                         fclose(f);
 309                         return strdup(mnt->mnt_dir);
 310                 }
 311         }
 312
 313         fclose(f);
 314         return NULL;
 315 }
 316
 317 static int do_show_tree(int argc, char **argv)
 318 {
 319         char *cgroup_root, *cgroup_alloced = NULL;
 320         int ret;
 321
 322         query_flags = 0;
 323
 324         if (!argc) {
 325                 cgroup_alloced = find_cgroup_root();
 326                 if (!cgroup_alloced) {
 327                         p_err("cgroup v2 isn't mounted");
 328                         return -1;
 329                 }
 330                 cgroup_root = cgroup_alloced;
 331         } else {
 332                 cgroup_root = GET_ARG();
 333
 334                 while (argc) {
 335                         if (is_prefix(*argv, "effective")) {
 336                                 if (query_flags & BPF_F_QUERY_EFFECTIVE) {
 337                                         p_err("duplicated argument: %s", *argv);
 338                                         return -1;
 339                                 }
 340                                 query_flags |= BPF_F_QUERY_EFFECTIVE;
 341                                 NEXT_ARG();
 342                         } else {
 343                                 p_err("expected no more arguments, 'effective', got: '%s'?",
 344                                       *argv);
 345                                 return -1;
 346                         }
 347                 }
 348         }
 349
 350         if (json_output)
 351                 jsonw_start_array(json_wtr);
 352         else
 353                 printf("%s\n"
 354                        "%-8s %-15s %-15s %-15s\n",
 355                        "CgroupPath",
 356                        "ID", "AttachType", "AttachFlags", "Name");
 357
 358         switch (nftw(cgroup_root, do_show_tree_fn, 1024, FTW_MOUNT)) {
 359         case NFTW_ERR:
 360                 p_err("can't iterate over %s: %s", cgroup_root,
 361                       strerror(errno));
 362                 ret = -1;
 363                 break;
 364         case SHOW_TREE_FN_ERR:
 365                 ret = -1;
 366                 break;
 367         default:
 368                 ret = 0;
 369         }
 370
 371         if (json_output)
 372                 jsonw_end_array(json_wtr);
 373
 374         free(cgroup_alloced);
 375
 376         return ret;
 377 }
 378
 379 static int do_attach(int argc, char **argv)
 380 {
 381         enum bpf_attach_type attach_type;
 382         int cgroup_fd, prog_fd;
 383         int attach_flags = 0;
 384         int ret = -1;
 385         int i;
 386
 387         if (argc < 4) {
 388                 p_err("too few parameters for cgroup attach");
 389                 goto exit;
 390         }
 391
 392         cgroup_fd = open(argv[0], O_RDONLY);
 393         if (cgroup_fd < 0) {
 394                 p_err("can't open cgroup %s", argv[0]);
 395                 goto exit;
 396         }
 397
 398         attach_type = parse_attach_type(argv[1]);
 399         if (attach_type == __MAX_BPF_ATTACH_TYPE) {
 400                 p_err("invalid attach type");
 401                 goto exit_cgroup;
 402         }
 403
 404         argc -= 2;
 405         argv = &argv[2];
 406         prog_fd = prog_parse_fd(&argc, &argv);
 407         if (prog_fd < 0)
 408                 goto exit_cgroup;
 409
 410         for (i = 0; i < argc; i++) {
 411                 if (is_prefix(argv[i], "multi")) {
 412                         attach_flags |= BPF_F_ALLOW_MULTI;
 413                 } else if (is_prefix(argv[i], "override")) {
 414                         attach_flags |= BPF_F_ALLOW_OVERRIDE;
 415                 } else {
 416                         p_err("unknown option: %s", argv[i]);
 417                         goto exit_cgroup;
 418                 }
 419         }
 420
 421         if (bpf_prog_attach(prog_fd, cgroup_fd, attach_type, attach_flags)) {
 422                 p_err("failed to attach program");
 423                 goto exit_prog;
 424         }
 425
 426         if (json_output)
 427                 jsonw_null(json_wtr);
 428
 429         ret = 0;
 430
 431 exit_prog:
 432         close(prog_fd);
 433 exit_cgroup:
 434         close(cgroup_fd);
 435 exit:
 436         return ret;
 437 }
 438
 439 static int do_detach(int argc, char **argv)
 440 {
 441         enum bpf_attach_type attach_type;
 442         int prog_fd, cgroup_fd;
 443         int ret = -1;
 444
 445         if (argc < 4) {
 446                 p_err("too few parameters for cgroup detach");
 447                 goto exit;
 448         }
 449
 450         cgroup_fd = open(argv[0], O_RDONLY);
 451         if (cgroup_fd < 0) {
 452                 p_err("can't open cgroup %s", argv[0]);
 453                 goto exit;
 454         }
 455
 456         attach_type = parse_attach_type(argv[1]);
 457         if (attach_type == __MAX_BPF_ATTACH_TYPE) {
 458                 p_err("invalid attach type");
 459                 goto exit_cgroup;
 460         }
 461
 462         argc -= 2;
 463         argv = &argv[2];
 464         prog_fd = prog_parse_fd(&argc, &argv);
 465         if (prog_fd < 0)
 466                 goto exit_cgroup;
 467
 468         if (bpf_prog_detach2(prog_fd, cgroup_fd, attach_type)) {
 469                 p_err("failed to detach program");
 470                 goto exit_prog;
 471         }
 472
 473         if (json_output)
 474                 jsonw_null(json_wtr);
 475
 476         ret = 0;
 477
 478 exit_prog:
 479         close(prog_fd);
 480 exit_cgroup:
 481         close(cgroup_fd);
 482 exit:
 483         return ret;
 484 }
 485
 486 static int do_help(int argc, char **argv)
 487 {
 488         if (json_output) {
 489                 jsonw_null(json_wtr);
 490                 return 0;
 491         }
 492
 493         fprintf(stderr,
 494                 "Usage: %1$s %2$s { show | list } CGROUP [**effective**]\n"
 495                 "       %1$s %2$s tree [CGROUP_ROOT] [**effective**]\n"
 496                 "       %1$s %2$s attach CGROUP ATTACH_TYPE PROG [ATTACH_FLAGS]\n"
 497                 "       %1$s %2$s detach CGROUP ATTACH_TYPE PROG\n"
 498                 "       %1$s %2$s help\n"
 499                 "\n"
 500                 HELP_SPEC_ATTACH_TYPES "\n"
 501                 "       " HELP_SPEC_ATTACH_FLAGS "\n"
 502                 "       " HELP_SPEC_PROGRAM "\n"
 503                 "       " HELP_SPEC_OPTIONS "\n"
 504                 "",
 505                 bin_name, argv[-2]);
 506
 507         return 0;
 508 }
 509
 510 static const struct cmd cmds[] = {
 511         { "show",       do_show },
 512         { "list",       do_show },
 513         { "tree",       do_show_tree },
 514         { "attach",     do_attach },
 515         { "detach",     do_detach },
 516         { "help",       do_help },
 517         { 0 }
 518 };
 519
 520 int do_cgroup(int argc, char **argv)
 521 {
 522         return cmd_select(cmds, argc, argv, do_help);
 523 }