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 |\n"         \
  32         "                        sock_release }"
  33
  34 static unsigned int query_flags;
  35
  36 static enum bpf_attach_type parse_attach_type(const char *str)
  37 {
  38         enum bpf_attach_type type;
  39
  40         for (type = 0; type < __MAX_BPF_ATTACH_TYPE; type++) {
  41                 if (attach_type_name[type] &&
  42                     is_prefix(str, attach_type_name[type]))
  43                         return type;
  44         }
  45
  46         return __MAX_BPF_ATTACH_TYPE;
  47 }
  48
  49 static int show_bpf_prog(int id, enum bpf_attach_type attach_type,
  50                          const char *attach_flags_str,
  51                          int level)
  52 {
  53         struct bpf_prog_info info = {};
  54         __u32 info_len = sizeof(info);
  55         int prog_fd;
  56
  57         prog_fd = bpf_prog_get_fd_by_id(id);
  58         if (prog_fd < 0)
  59                 return -1;
  60
  61         if (bpf_obj_get_info_by_fd(prog_fd, &info, &info_len)) {
  62                 close(prog_fd);
  63                 return -1;
  64         }
  65
  66         if (json_output) {
  67                 jsonw_start_object(json_wtr);
  68                 jsonw_uint_field(json_wtr, "id", info.id);
  69                 if (attach_type < ARRAY_SIZE(attach_type_name))
  70                         jsonw_string_field(json_wtr, "attach_type",
  71                                            attach_type_name[attach_type]);
  72                 else
  73                         jsonw_uint_field(json_wtr, "attach_type", attach_type);
  74                 jsonw_string_field(json_wtr, "attach_flags",
  75                                    attach_flags_str);
  76                 jsonw_string_field(json_wtr, "name", info.name);
  77                 jsonw_end_object(json_wtr);
  78         } else {
  79                 printf("%s%-8u ", level ? "    " : "", info.id);
  80                 if (attach_type < ARRAY_SIZE(attach_type_name))
  81                         printf("%-15s", attach_type_name[attach_type]);
  82                 else
  83                         printf("type %-10u", attach_type);
  84                 printf(" %-15s %-15s\n", attach_flags_str, info.name);
  85         }
  86
  87         close(prog_fd);
  88         return 0;
  89 }
  90
  91 static int count_attached_bpf_progs(int cgroup_fd, enum bpf_attach_type type)
  92 {
  93         __u32 prog_cnt = 0;
  94         int ret;
  95
  96         ret = bpf_prog_query(cgroup_fd, type, query_flags, NULL,
  97                              NULL, &prog_cnt);
  98         if (ret)
  99                 return -1;
 100
 101         return prog_cnt;
 102 }
 103
 104 static int cgroup_has_attached_progs(int cgroup_fd)
 105 {
 106         enum bpf_attach_type type;
 107         bool no_prog = true;
 108
 109         for (type = 0; type < __MAX_BPF_ATTACH_TYPE; type++) {
 110                 int count = count_attached_bpf_progs(cgroup_fd, type);
 111
 112                 if (count < 0 && errno != EINVAL)
 113                         return -1;
 114
 115                 if (count > 0) {
 116                         no_prog = false;
 117                         break;
 118                 }
 119         }
 120
 121         return no_prog ? 0 : 1;
 122 }
 123 static int show_attached_bpf_progs(int cgroup_fd, enum bpf_attach_type type,
 124                                    int level)
 125 {
 126         const char *attach_flags_str;
 127         __u32 prog_ids[1024] = {0};
 128         __u32 prog_cnt, iter;
 129         __u32 attach_flags;
 130         char buf[32];
 131         int ret;
 132
 133         prog_cnt = ARRAY_SIZE(prog_ids);
 134         ret = bpf_prog_query(cgroup_fd, type, query_flags, &attach_flags,
 135                              prog_ids, &prog_cnt);
 136         if (ret)
 137                 return ret;
 138
 139         if (prog_cnt == 0)
 140                 return 0;
 141
 142         switch (attach_flags) {
 143         case BPF_F_ALLOW_MULTI:
 144                 attach_flags_str = "multi";
 145                 break;
 146         case BPF_F_ALLOW_OVERRIDE:
 147                 attach_flags_str = "override";
 148                 break;
 149         case 0:
 150                 attach_flags_str = "";
 151                 break;
 152         default:
 153                 snprintf(buf, sizeof(buf), "unknown(%x)", attach_flags);
 154                 attach_flags_str = buf;
 155         }
 156
 157         for (iter = 0; iter < prog_cnt; iter++)
 158                 show_bpf_prog(prog_ids[iter], type,
 159                               attach_flags_str, level);
 160
 161         return 0;
 162 }
 163
 164 static int do_show(int argc, char **argv)
 165 {
 166         enum bpf_attach_type type;
 167         int has_attached_progs;
 168         const char *path;
 169         int cgroup_fd;
 170         int ret = -1;
 171
 172         query_flags = 0;
 173
 174         if (!REQ_ARGS(1))
 175                 return -1;
 176         path = GET_ARG();
 177
 178         while (argc) {
 179                 if (is_prefix(*argv, "effective")) {
 180                         if (query_flags & BPF_F_QUERY_EFFECTIVE) {
 181                                 p_err("duplicated argument: %s", *argv);
 182                                 return -1;
 183                         }
 184                         query_flags |= BPF_F_QUERY_EFFECTIVE;
 185                         NEXT_ARG();
 186                 } else {
 187                         p_err("expected no more arguments, 'effective', got: '%s'?",
 188                               *argv);
 189                         return -1;
 190                 }
 191         }
 192
 193         cgroup_fd = open(path, O_RDONLY);
 194         if (cgroup_fd < 0) {
 195                 p_err("can't open cgroup %s", path);
 196                 goto exit;
 197         }
 198
 199         has_attached_progs = cgroup_has_attached_progs(cgroup_fd);
 200         if (has_attached_progs < 0) {
 201                 p_err("can't query bpf programs attached to %s: %s",
 202                       path, strerror(errno));
 203                 goto exit_cgroup;
 204         } else if (!has_attached_progs) {
 205                 ret = 0;
 206                 goto exit_cgroup;
 207         }
 208
 209         if (json_output)
 210                 jsonw_start_array(json_wtr);
 211         else
 212                 printf("%-8s %-15s %-15s %-15s\n", "ID", "AttachType",
 213                        "AttachFlags", "Name");
 214
 215         for (type = 0; type < __MAX_BPF_ATTACH_TYPE; type++) {
 216                 /*
 217                  * Not all attach types may be supported, so it's expected,
 218                  * that some requests will fail.
 219                  * If we were able to get the show for at least one
 220                  * attach type, let's return 0.
 221                  */
 222                 if (show_attached_bpf_progs(cgroup_fd, type, 0) == 0)
 223                         ret = 0;
 224         }
 225
 226         if (json_output)
 227                 jsonw_end_array(json_wtr);
 228
 229 exit_cgroup:
 230         close(cgroup_fd);
 231 exit:
 232         return ret;
 233 }
 234
 235 /*
 236  * To distinguish nftw() errors and do_show_tree_fn() errors
 237  * and avoid duplicating error messages, let's return -2
 238  * from do_show_tree_fn() in case of error.
 239  */
 240 #define NFTW_ERR                -1
 241 #define SHOW_TREE_FN_ERR        -2
 242 static int do_show_tree_fn(const char *fpath, const struct stat *sb,
 243                            int typeflag, struct FTW *ftw)
 244 {
 245         enum bpf_attach_type type;
 246         int has_attached_progs;
 247         int cgroup_fd;
 248
 249         if (typeflag != FTW_D)
 250                 return 0;
 251
 252         cgroup_fd = open(fpath, O_RDONLY);
 253         if (cgroup_fd < 0) {
 254                 p_err("can't open cgroup %s: %s", fpath, strerror(errno));
 255                 return SHOW_TREE_FN_ERR;
 256         }
 257
 258         has_attached_progs = cgroup_has_attached_progs(cgroup_fd);
 259         if (has_attached_progs < 0) {
 260                 p_err("can't query bpf programs attached to %s: %s",
 261                       fpath, strerror(errno));
 262                 close(cgroup_fd);
 263                 return SHOW_TREE_FN_ERR;
 264         } else if (!has_attached_progs) {
 265                 close(cgroup_fd);
 266                 return 0;
 267         }
 268
 269         if (json_output) {
 270                 jsonw_start_object(json_wtr);
 271                 jsonw_string_field(json_wtr, "cgroup", fpath);
 272                 jsonw_name(json_wtr, "programs");
 273                 jsonw_start_array(json_wtr);
 274         } else {
 275                 printf("%s\n", fpath);
 276         }
 277
 278         for (type = 0; type < __MAX_BPF_ATTACH_TYPE; type++)
 279                 show_attached_bpf_progs(cgroup_fd, type, ftw->level);
 280
 281         if (errno == EINVAL)
 282                 /* Last attach type does not support query.
 283                  * Do not report an error for this, especially because batch
 284                  * mode would stop processing commands.
 285                  */
 286                 errno = 0;
 287
 288         if (json_output) {
 289                 jsonw_end_array(json_wtr);
 290                 jsonw_end_object(json_wtr);
 291         }
 292
 293         close(cgroup_fd);
 294
 295         return 0;
 296 }
 297
 298 static char *find_cgroup_root(void)
 299 {
 300         struct mntent *mnt;
 301         FILE *f;
 302
 303         f = fopen("/proc/mounts", "r");
 304         if (f == NULL)
 305                 return NULL;
 306
 307         while ((mnt = getmntent(f))) {
 308                 if (strcmp(mnt->mnt_type, "cgroup2") == 0) {
 309                         fclose(f);
 310                         return strdup(mnt->mnt_dir);
 311                 }
 312         }
 313
 314         fclose(f);
 315         return NULL;
 316 }
 317
 318 static int do_show_tree(int argc, char **argv)
 319 {
 320         char *cgroup_root, *cgroup_alloced = NULL;
 321         int ret;
 322
 323         query_flags = 0;
 324
 325         if (!argc) {
 326                 cgroup_alloced = find_cgroup_root();
 327                 if (!cgroup_alloced) {
 328                         p_err("cgroup v2 isn't mounted");
 329                         return -1;
 330                 }
 331                 cgroup_root = cgroup_alloced;
 332         } else {
 333                 cgroup_root = GET_ARG();
 334
 335                 while (argc) {
 336                         if (is_prefix(*argv, "effective")) {
 337                                 if (query_flags & BPF_F_QUERY_EFFECTIVE) {
 338                                         p_err("duplicated argument: %s", *argv);
 339                                         return -1;
 340                                 }
 341                                 query_flags |= BPF_F_QUERY_EFFECTIVE;
 342                                 NEXT_ARG();
 343                         } else {
 344                                 p_err("expected no more arguments, 'effective', got: '%s'?",
 345                                       *argv);
 346                                 return -1;
 347                         }
 348                 }
 349         }
 350
 351         if (json_output)
 352                 jsonw_start_array(json_wtr);
 353         else
 354                 printf("%s\n"
 355                        "%-8s %-15s %-15s %-15s\n",
 356                        "CgroupPath",
 357                        "ID", "AttachType", "AttachFlags", "Name");
 358
 359         switch (nftw(cgroup_root, do_show_tree_fn, 1024, FTW_MOUNT)) {
 360         case NFTW_ERR:
 361                 p_err("can't iterate over %s: %s", cgroup_root,
 362                       strerror(errno));
 363                 ret = -1;
 364                 break;
 365         case SHOW_TREE_FN_ERR:
 366                 ret = -1;
 367                 break;
 368         default:
 369                 ret = 0;
 370         }
 371
 372         if (json_output)
 373                 jsonw_end_array(json_wtr);
 374
 375         free(cgroup_alloced);
 376
 377         return ret;
 378 }
 379
 380 static int do_attach(int argc, char **argv)
 381 {
 382         enum bpf_attach_type attach_type;
 383         int cgroup_fd, prog_fd;
 384         int attach_flags = 0;
 385         int ret = -1;
 386         int i;
 387
 388         if (argc < 4) {
 389                 p_err("too few parameters for cgroup attach");
 390                 goto exit;
 391         }
 392
 393         cgroup_fd = open(argv[0], O_RDONLY);
 394         if (cgroup_fd < 0) {
 395                 p_err("can't open cgroup %s", argv[0]);
 396                 goto exit;
 397         }
 398
 399         attach_type = parse_attach_type(argv[1]);
 400         if (attach_type == __MAX_BPF_ATTACH_TYPE) {
 401                 p_err("invalid attach type");
 402                 goto exit_cgroup;
 403         }
 404
 405         argc -= 2;
 406         argv = &argv[2];
 407         prog_fd = prog_parse_fd(&argc, &argv);
 408         if (prog_fd < 0)
 409                 goto exit_cgroup;
 410
 411         for (i = 0; i < argc; i++) {
 412                 if (is_prefix(argv[i], "multi")) {
 413                         attach_flags |= BPF_F_ALLOW_MULTI;
 414                 } else if (is_prefix(argv[i], "override")) {
 415                         attach_flags |= BPF_F_ALLOW_OVERRIDE;
 416                 } else {
 417                         p_err("unknown option: %s", argv[i]);
 418                         goto exit_cgroup;
 419                 }
 420         }
 421
 422         if (bpf_prog_attach(prog_fd, cgroup_fd, attach_type, attach_flags)) {
 423                 p_err("failed to attach program");
 424                 goto exit_prog;
 425         }
 426
 427         if (json_output)
 428                 jsonw_null(json_wtr);
 429
 430         ret = 0;
 431
 432 exit_prog:
 433         close(prog_fd);
 434 exit_cgroup:
 435         close(cgroup_fd);
 436 exit:
 437         return ret;
 438 }
 439
 440 static int do_detach(int argc, char **argv)
 441 {
 442         enum bpf_attach_type attach_type;
 443         int prog_fd, cgroup_fd;
 444         int ret = -1;
 445
 446         if (argc < 4) {
 447                 p_err("too few parameters for cgroup detach");
 448                 goto exit;
 449         }
 450
 451         cgroup_fd = open(argv[0], O_RDONLY);
 452         if (cgroup_fd < 0) {
 453                 p_err("can't open cgroup %s", argv[0]);
 454                 goto exit;
 455         }
 456
 457         attach_type = parse_attach_type(argv[1]);
 458         if (attach_type == __MAX_BPF_ATTACH_TYPE) {
 459                 p_err("invalid attach type");
 460                 goto exit_cgroup;
 461         }
 462
 463         argc -= 2;
 464         argv = &argv[2];
 465         prog_fd = prog_parse_fd(&argc, &argv);
 466         if (prog_fd < 0)
 467                 goto exit_cgroup;
 468
 469         if (bpf_prog_detach2(prog_fd, cgroup_fd, attach_type)) {
 470                 p_err("failed to detach program");
 471                 goto exit_prog;
 472         }
 473
 474         if (json_output)
 475                 jsonw_null(json_wtr);
 476
 477         ret = 0;
 478
 479 exit_prog:
 480         close(prog_fd);
 481 exit_cgroup:
 482         close(cgroup_fd);
 483 exit:
 484         return ret;
 485 }
 486
 487 static int do_help(int argc, char **argv)
 488 {
 489         if (json_output) {
 490                 jsonw_null(json_wtr);
 491                 return 0;
 492         }
 493
 494         fprintf(stderr,
 495                 "Usage: %1$s %2$s { show | list } CGROUP [**effective**]\n"
 496                 "       %1$s %2$s tree [CGROUP_ROOT] [**effective**]\n"
 497                 "       %1$s %2$s attach CGROUP ATTACH_TYPE PROG [ATTACH_FLAGS]\n"
 498                 "       %1$s %2$s detach CGROUP ATTACH_TYPE PROG\n"
 499                 "       %1$s %2$s help\n"
 500                 "\n"
 501                 HELP_SPEC_ATTACH_TYPES "\n"
 502                 "       " HELP_SPEC_ATTACH_FLAGS "\n"
 503                 "       " HELP_SPEC_PROGRAM "\n"
 504                 "       " HELP_SPEC_OPTIONS "\n"
 505                 "",
 506                 bin_name, argv[-2]);
 507
 508         return 0;
 509 }
 510
 511 static const struct cmd cmds[] = {
 512         { "show",       do_show },
 513         { "list",       do_show },
 514         { "tree",       do_show_tree },
 515         { "attach",     do_attach },
 516         { "detach",     do_detach },
 517         { "help",       do_help },
 518         { 0 }
 519 };
 520
 521 int do_cgroup(int argc, char **argv)
 522 {
 523         return cmd_select(cmds, argc, argv, do_help);
 524 }