src/cgroup-util.c

   1 /*-*- Mode: C; c-basic-offset: 8 -*-*/
   2
   3 /***
   4   This file is part of systemd.
   5
   6   Copyright 2010 Lennart Poettering
   7
   8   systemd is free software; you can redistribute it and/or modify it
   9   under the terms of the GNU General Public License as published by
  10   the Free Software Foundation; either version 2 of the License, or
  11   (at your option) any later version.
  12
  13   systemd is distributed in the hope that it will be useful, but
  14   WITHOUT ANY WARRANTY; without even the implied warranty of
  15   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  16   General Public License for more details.
  17
  18   You should have received a copy of the GNU General Public License
  19   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  20 ***/
  21
  22 #include <errno.h>
  23 #include <unistd.h>
  24 #include <signal.h>
  25 #include <string.h>
  26 #include <stdlib.h>
  27
  28 #include <libcgroup.h>
  29
  30 #include "cgroup-util.h"
  31 #include "log.h"
  32 #include "set.h"
  33 #include "macro.h"
  34 #include "util.h"
  35
  36 int cg_translate_error(int error, int _errno) {
  37
  38         switch (error) {
  39
  40         case ECGROUPNOTCOMPILED:
  41         case ECGROUPNOTMOUNTED:
  42         case ECGROUPNOTEXIST:
  43         case ECGROUPNOTCREATED:
  44                 return -ENOENT;
  45
  46         case ECGINVAL:
  47                 return -EINVAL;
  48
  49         case ECGROUPNOTALLOWED:
  50                 return -EPERM;
  51
  52         case ECGOTHER:
  53                 return -_errno;
  54         }
  55
  56         return -EIO;
  57 }
  58
  59 static struct cgroup* cg_new(const char *controller, const char *path) {
  60         struct cgroup *cgroup;
  61
  62         assert(path);
  63         assert(controller);
  64
  65         if (!(cgroup = cgroup_new_cgroup(path)))
  66                 return NULL;
  67
  68         if (!cgroup_add_controller(cgroup, controller)) {
  69                 cgroup_free(&cgroup);
  70                 return NULL;
  71         }
  72
  73         return cgroup;
  74 }
  75
  76 int cg_kill(const char *controller, const char *path, int sig, bool ignore_self) {
  77         bool killed = false, done = false;
  78         Set *s;
  79         pid_t my_pid;
  80         int r, ret = 0;
  81
  82         assert(controller);
  83         assert(path);
  84         assert(sig >= 0);
  85
  86         /* This goes through the tasks list and kills them all. This
  87          * is repeated until no further processes are added to the
  88          * tasks list, to properly handle forking processes */
  89
  90         if (!(s = set_new(trivial_hash_func, trivial_compare_func)))
  91                 return -ENOMEM;
  92
  93         my_pid = getpid();
  94
  95         do {
  96                 void *iterator = NULL;
  97                 pid_t pid = 0;
  98
  99                 done = true;
 100
 101                 r = cgroup_get_task_begin(path, controller, &iterator, &pid);
 102                 while (r == 0) {
 103
 104                         if (pid == my_pid && ignore_self)
 105                                 goto next;
 106
 107                         if (set_get(s, INT_TO_PTR(pid)) == INT_TO_PTR(pid))
 108                                 goto next;
 109
 110                         /* If we haven't killed this process yet, kill
 111                          * it */
 112
 113                         if (kill(pid, sig) < 0 && errno != ESRCH) {
 114                                 if (ret == 0)
 115                                         ret = -errno;
 116                         }
 117
 118                         killed = true;
 119                         done = false;
 120
 121                         if ((r = set_put(s, INT_TO_PTR(pid))) < 0)
 122                                 goto loop_exit;
 123
 124                 next:
 125                         r = cgroup_get_task_next(&iterator, &pid);
 126                 }
 127
 128                 if (r == 0 || r == ECGEOF)
 129                         r = 0;
 130                 else if (r == ECGOTHER && errno == ENOENT)
 131                         r = -ESRCH;
 132                 else
 133                         r = cg_translate_error(r, errno);
 134
 135         loop_exit:
 136                 assert_se(cgroup_get_task_end(&iterator) == 0);
 137
 138                 /* To avoid racing against processes which fork
 139                  * quicker than we can kill them we repeat this until
 140                  * no new pids need to be killed. */
 141
 142         } while (!done && r >= 0);
 143
 144         set_free(s);
 145
 146         if (ret < 0)
 147                 return ret;
 148
 149         if (r < 0)
 150                 return r;
 151
 152         return !!killed;
 153 }
 154
 155 int cg_kill_recursive(const char *controller, const char *path, int sig, bool ignore_self) {
 156         struct cgroup_file_info info;
 157         int level = 0, r, ret = 0;
 158         void *iterator = NULL;
 159         bool killed = false;
 160
 161         assert(path);
 162         assert(controller);
 163         assert(sig >= 0);
 164
 165         zero(info);
 166
 167         r = cgroup_walk_tree_begin(controller, path, 0, &iterator, &info, &level);
 168         while (r == 0) {
 169                 int k;
 170                 char *p;
 171
 172                 if (info.type != CGROUP_FILE_TYPE_DIR)
 173                         goto next;
 174
 175                 if (asprintf(&p, "%s/%s", path, info.path) < 0) {
 176                         ret = -ENOMEM;
 177                         break;
 178                 }
 179
 180                 k = cg_kill(controller, p, sig, ignore_self);
 181                 free(p);
 182
 183                 if (k < 0) {
 184                         if (ret == 0)
 185                                 ret = k;
 186                 } else if (k > 0)
 187                         killed = true;
 188
 189         next:
 190
 191                 r = cgroup_walk_tree_next(0, &iterator, &info, level);
 192         }
 193
 194         if (ret == 0) {
 195                 if (r == 0 || r == ECGEOF)
 196                         ret = !!killed;
 197                 else if (r == ECGOTHER && errno == ENOENT)
 198                         ret = -ESRCH;
 199                 else
 200                         ret = cg_translate_error(r, errno);
 201         }
 202
 203         assert_se(cgroup_walk_tree_end(&iterator) == 0);
 204
 205         return ret;
 206 }
 207
 208 int cg_kill_recursive_and_wait(const char *controller, const char *path) {
 209         unsigned i;
 210
 211         assert(path);
 212         assert(controller);
 213
 214         /* This safely kills all processes; first it sends a SIGTERM,
 215          * then checks 8 times after 50ms whether the group is
 216          * now empty, and finally kills everything that is left with
 217          * SIGKILL */
 218
 219         for (i = 0; i < 10; i++) {
 220 int sig, r;
 221
 222                 if (i <= 0)
 223                         sig = SIGTERM;
 224                 else if (i >= 9)
 225                         sig = SIGKILL;
 226                 else
 227                         sig = 0;
 228
 229                 if ((r = cg_kill_recursive(controller, path, sig, true)) <= 0)
 230                         return r;
 231
 232                 usleep(50 * USEC_PER_MSEC);
 233         }
 234
 235         return 0;
 236 }
 237
 238 int cg_migrate(const char *controller, const char *from, const char *to, bool ignore_self) {
 239         bool migrated = false, done = false;
 240         struct cgroup *dest;
 241         int r, ret = 0;
 242         pid_t my_pid;
 243
 244         assert(controller);
 245         assert(from);
 246         assert(to);
 247
 248         if (!(dest = cg_new(controller, to)))
 249                 return -ENOMEM;
 250
 251         my_pid = getpid();
 252
 253         do {
 254                 void *iterator = NULL;
 255                 pid_t pid = 0;
 256
 257                 done = true;
 258
 259                 r = cgroup_get_task_begin(from, controller, &iterator, &pid);
 260                 while (r == 0) {
 261
 262                         if (pid == my_pid && ignore_self)
 263                                 goto next;
 264
 265                         if ((r = cgroup_attach_task_pid(dest, pid)) != 0) {
 266                                 if (ret == 0)
 267                                         r = cg_translate_error(r, errno);
 268                         }
 269
 270                         migrated = true;
 271                         done = false;
 272
 273                 next:
 274
 275                         r = cgroup_get_task_next(&iterator, &pid);
 276                 }
 277
 278                 if (r == 0 || r == ECGEOF)
 279                         r = 0;
 280                 else if (r == ECGOTHER && errno == ENOENT)
 281                         r = -ESRCH;
 282                 else
 283                         r = cg_translate_error(r, errno);
 284
 285                 assert_se(cgroup_get_task_end(&iterator) == 0);
 286
 287         } while (!done && r >= 0);
 288
 289         cgroup_free(&dest);
 290
 291         if (ret < 0)
 292                 return ret;
 293
 294         if (r < 0)
 295                 return r;
 296
 297         return !!migrated;
 298 }
 299
 300 int cg_migrate_recursive(const char *controller, const char *from, const char *to, bool ignore_self) {
 301         struct cgroup_file_info info;
 302         int level = 0, r, ret = 0;
 303         void *iterator = NULL;
 304         bool migrated = false;
 305
 306         assert(controller);
 307         assert(from);
 308         assert(to);
 309
 310         zero(info);
 311
 312         r = cgroup_walk_tree_begin(controller, from, 0, &iterator, &info, &level);
 313         while (r == 0) {
 314                 int k;
 315                 char *p;
 316
 317                 if (info.type != CGROUP_FILE_TYPE_DIR)
 318                         goto next;
 319
 320                 if (asprintf(&p, "%s/%s", from, info.path) < 0) {
 321                         ret = -ENOMEM;
 322                         break;
 323                 }
 324
 325                 k = cg_migrate(controller, p, to, ignore_self);
 326                 free(p);
 327
 328                 if (k < 0) {
 329                         if (ret == 0)
 330                                 ret = k;
 331                 } else if (k > 0)
 332                         migrated = true;
 333
 334         next:
 335                 r = cgroup_walk_tree_next(0, &iterator, &info, level);
 336         }
 337
 338         if (ret == 0) {
 339                 if (r == 0 || r == ECGEOF)
 340                         r = !!migrated;
 341                 else if (r == ECGOTHER && errno == ENOENT)
 342                         r = -ESRCH;
 343                 else
 344                         r = cg_translate_error(r, errno);
 345         }
 346
 347         assert_se(cgroup_walk_tree_end(&iterator) == 0);
 348
 349         return ret;
 350 }
 351
 352 int cg_get_path(const char *controller, const char *path, const char *suffix, char **fs) {
 353         char *mp;
 354         int r;
 355
 356         assert(controller);
 357         assert(path);
 358
 359         if ((r = cgroup_get_subsys_mount_point(controller, &mp)) != 0)
 360                 return cg_translate_error(r, errno);
 361
 362         if (suffix)
 363                 r = asprintf(fs, "%s/%s/%s", mp, path, suffix);
 364         else
 365                 r = asprintf(fs, "%s/%s", mp, path);
 366
 367         free(mp);
 368
 369         return r < 0 ? -ENOMEM : 0;
 370 }
 371
 372 int cg_trim(const char *controller, const char *path, bool delete_root) {
 373         char *fs;
 374         int r;
 375
 376         assert(controller);
 377         assert(path);
 378
 379         if ((r = cg_get_path(controller, path, NULL, &fs)) < 0)
 380                 return r;
 381
 382         r = rm_rf(fs, true, delete_root);
 383         free(fs);
 384
 385         return r;
 386 }
 387
 388 int cg_delete(const char *controller, const char *path) {
 389         struct cgroup *cg;
 390         int r;
 391
 392         assert(controller);
 393         assert(path);
 394
 395         if (!(cg = cg_new(controller, path)))
 396                 return -ENOMEM;
 397
 398         if ((r = cgroup_delete_cgroup_ext(cg, CGFLAG_DELETE_RECURSIVE|CGFLAG_DELETE_IGNORE_MIGRATION)) != 0) {
 399                 r = cg_translate_error(r, errno);
 400                 goto finish;
 401         }
 402
 403         r = 0;
 404
 405 finish:
 406         cgroup_free(&cg);
 407
 408         return r;
 409 }
 410
 411 int cg_create(const char *controller, const char *path) {
 412         struct cgroup *cg;
 413         int r;
 414
 415         assert(controller);
 416         assert(path);
 417
 418         if (!(cg = cg_new(controller, path)))
 419                 return -ENOMEM;
 420
 421         if ((r = cgroup_create_cgroup(cg, 1)) != 0) {
 422                 r = cg_translate_error(r, errno);
 423                 goto finish;
 424         }
 425
 426         r = 0;
 427
 428 finish:
 429         cgroup_free(&cg);
 430
 431         return r;
 432 }
 433
 434 int cg_attach(const char *controller, const char *path, pid_t pid) {
 435         struct cgroup *cg;
 436         int r;
 437
 438         assert(controller);
 439         assert(path);
 440         assert(pid >= 0);
 441
 442         if (!(cg = cg_new(controller, path)))
 443                 return -ENOMEM;
 444
 445         if (pid == 0)
 446                 pid = getpid();
 447
 448         if ((r = cgroup_attach_task_pid(cg, pid))) {
 449                 r = cg_translate_error(r, errno);
 450                 goto finish;
 451         }
 452
 453         r = 0;
 454
 455 finish:
 456         cgroup_free(&cg);
 457
 458         return r;
 459 }
 460
 461 int cg_create_and_attach(const char *controller, const char *path, pid_t pid) {
 462         struct cgroup *cg;
 463         int r;
 464
 465         assert(controller);
 466         assert(path);
 467         assert(pid >= 0);
 468
 469         if (!(cg = cg_new(controller, path)))
 470                 return -ENOMEM;
 471
 472         if ((r = cgroup_create_cgroup(cg, 1)) != 0) {
 473                 r = cg_translate_error(r, errno);
 474                 goto finish;
 475         }
 476
 477         if (pid == 0)
 478                 pid = getpid();
 479
 480         if ((r = cgroup_attach_task_pid(cg, pid))) {
 481                 r = cg_translate_error(r, errno);
 482                 goto finish;
 483         }
 484
 485         r = 0;
 486
 487 finish:
 488         cgroup_free(&cg);
 489
 490         return r;
 491 }
 492
 493 int cg_set_group_access(const char *controller, const char *path, mode_t mode, uid_t uid, gid_t gid) {
 494         char *fs;
 495         int r;
 496
 497         assert(controller);
 498         assert(path);
 499
 500         if ((r = cg_get_path(controller, path, NULL, &fs)) < 0)
 501                 return r;
 502
 503         r = chmod_and_chown(fs, mode, uid, gid);
 504         free(fs);
 505
 506         return r;
 507 }
 508
 509 int cg_set_task_access(const char *controller, const char *path, mode_t mode, uid_t uid, gid_t gid) {
 510         char *fs;
 511         int r;
 512
 513         assert(controller);
 514         assert(path);
 515
 516         if ((r = cg_get_path(controller, path, "tasks", &fs)) < 0)
 517                 return r;
 518
 519         r = chmod_and_chown(fs, mode, uid, gid);
 520         free(fs);
 521
 522         return r;
 523 }
 524
 525 int cg_get_by_pid(const char *controller, pid_t pid, char **path) {
 526         int r;
 527         char *p = NULL;
 528
 529         assert(controller);
 530         assert(pid > 0);
 531         assert(path);
 532
 533         if ((r = cgroup_get_current_controller_path(pid, controller, &p)) != 0)
 534                 return cg_translate_error(r, errno);
 535
 536         assert(p);
 537
 538         *path = p;
 539         return 0;
 540 }
 541
 542 int cg_install_release_agent(const char *controller, const char *agent) {
 543         char *mp = NULL, *path = NULL, *contents = NULL, *line = NULL, *sc;
 544         int r;
 545
 546         assert(controller);
 547         assert(agent);
 548
 549         if ((r = cgroup_get_subsys_mount_point(controller, &mp)) != 0)
 550                 return cg_translate_error(r, errno);
 551
 552         if (asprintf(&path, "%s/release_agent", mp) < 0) {
 553                 r = -ENOMEM;
 554                 goto finish;
 555         }
 556
 557         if ((r = read_one_line_file(path, &contents)) < 0)
 558                 goto finish;
 559
 560         sc = strstrip(contents);
 561
 562         if (sc[0] == 0) {
 563
 564                 if (asprintf(&line, "%s\n", agent) < 0) {
 565                         r = -ENOMEM;
 566                         goto finish;
 567                 }
 568
 569                 if ((r = write_one_line_file(path, line)) < 0)
 570                         goto finish;
 571
 572         } else if (!streq(sc, agent)) {
 573                 r = -EEXIST;
 574                 goto finish;
 575         }
 576
 577         free(path);
 578         path = NULL;
 579         if (asprintf(&path, "%s/notify_on_release", mp) < 0) {
 580                 r = -ENOMEM;
 581                 goto finish;
 582         }
 583
 584         free(contents);
 585         contents = NULL;
 586         if ((r = read_one_line_file(path, &contents)) < 0)
 587                 goto finish;
 588
 589         sc = strstrip(contents);
 590
 591         if (streq(sc, "0")) {
 592                 if ((r = write_one_line_file(path, "1\n")) < 0)
 593                         goto finish;
 594         } else if (!streq(sc, "1")) {
 595                 r = -EIO;
 596                 goto finish;
 597         }
 598
 599         r = 0;
 600
 601 finish:
 602         free(mp);
 603         free(path);
 604         free(contents);
 605         free(line);
 606
 607         return r;
 608 }
 609
 610 int cg_is_empty(const char *controller, const char *path, bool ignore_self) {
 611         void *iterator = NULL;
 612         pid_t pid = 0;
 613         int r;
 614
 615         assert(controller);
 616         assert(path);
 617
 618         r = cgroup_get_task_begin(path, controller, &iterator, &pid);
 619         while (r == 0) {
 620
 621                 if (ignore_self&& pid == getpid())
 622                         goto next;
 623
 624                 break;
 625
 626         next:
 627                 r = cgroup_get_task_next(&iterator, &pid);
 628         }
 629
 630
 631         if (r == ECGEOF)
 632                 r = 1;
 633         else if (r != 0)
 634                 r = cg_translate_error(r, errno);
 635         else
 636                 r = 0;
 637
 638         assert_se(cgroup_get_task_end(&iterator) == 0);
 639
 640         return r;
 641 }
 642
 643 int cg_is_empty_recursive(const char *controller, const char *path, bool ignore_self) {
 644         struct cgroup_file_info info;
 645         int level = 0, r, ret = 0;
 646         void *iterator = NULL;
 647         bool empty = true;
 648
 649         assert(controller);
 650         assert(path);
 651
 652         zero(info);
 653
 654         r = cgroup_walk_tree_begin(controller, path, 0, &iterator, &info, &level);
 655         while (r == 0) {
 656                 int k;
 657                 char *p;
 658
 659                 if (info.type != CGROUP_FILE_TYPE_DIR)
 660                         goto next;
 661
 662                 if (asprintf(&p, "%s/%s", path, info.path) < 0) {
 663                         ret = -ENOMEM;
 664                         break;
 665                 }
 666
 667                 k = cg_is_empty(controller, p, ignore_self);
 668                 free(p);
 669
 670                 if (k < 0) {
 671                         ret = k;
 672                         break;
 673                 } else if (k == 0) {
 674                         empty = false;
 675                         break;
 676                 }
 677
 678         next:
 679                 r = cgroup_walk_tree_next(0, &iterator, &info, level);
 680         }
 681
 682         if (ret == 0) {
 683                 if (r == 0 || r == ECGEOF)
 684                         ret = !!empty;
 685                 else if (r == ECGOTHER && errno == ENOENT)
 686                         ret = -ESRCH;
 687                 else
 688                         ret = cg_translate_error(r, errno);
 689         }
 690
 691         assert_se(cgroup_walk_tree_end(&iterator) == 0);
 692
 693         return ret;
 694 }