src/basic/cgroup-util.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2 /***
   3   This file is part of systemd.
   4
   5   Copyright 2010 Lennart Poettering
   6
   7   systemd is free software; you can redistribute it and/or modify it
   8   under the terms of the GNU Lesser General Public License as published by
   9   the Free Software Foundation; either version 2.1 of the License, or
  10   (at your option) any later version.
  11
  12   systemd is distributed in the hope that it will be useful, but
  13   WITHOUT ANY WARRANTY; without even the implied warranty of
  14   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  15   Lesser General Public License for more details.
  16
  17   You should have received a copy of the GNU Lesser General Public License
  18   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  19 ***/
  20
  21 #include <dirent.h>
  22 #include <errno.h>
  23 #include <ftw.h>
  24 #include <limits.h>
  25 #include <signal.h>
  26 #include <stddef.h>
  27 #include <stdio_ext.h>
  28 #include <stdlib.h>
  29 #include <string.h>
  30 #include <sys/stat.h>
  31 #include <sys/statfs.h>
  32 #include <sys/types.h>
  33 #include <sys/xattr.h>
  34 #include <unistd.h>
  35
  36 #include "alloc-util.h"
  37 #include "cgroup-util.h"
  38 #include "def.h"
  39 #include "dirent-util.h"
  40 #include "extract-word.h"
  41 #include "fd-util.h"
  42 #include "fileio.h"
  43 #include "format-util.h"
  44 #include "fs-util.h"
  45 #include "log.h"
  46 #include "login-util.h"
  47 #include "macro.h"
  48 #include "missing.h"
  49 #include "mkdir.h"
  50 #include "parse-util.h"
  51 #include "path-util.h"
  52 #include "proc-cmdline.h"
  53 #include "process-util.h"
  54 #include "set.h"
  55 #include "special.h"
  56 #include "stat-util.h"
  57 #include "stdio-util.h"
  58 #include "string-table.h"
  59 #include "string-util.h"
  60 #include "strv.h"
  61 #include "unit-name.h"
  62 #include "user-util.h"
  63
  64 int cg_enumerate_processes(const char *controller, const char *path, FILE **_f) {
  65         _cleanup_free_ char *fs = NULL;
  66         FILE *f;
  67         int r;
  68
  69         assert(_f);
  70
  71         r = cg_get_path(controller, path, "cgroup.procs", &fs);
  72         if (r < 0)
  73                 return r;
  74
  75         f = fopen(fs, "re");
  76         if (!f)
  77                 return -errno;
  78
  79         *_f = f;
  80         return 0;
  81 }
  82
  83 int cg_read_pid(FILE *f, pid_t *_pid) {
  84         unsigned long ul;
  85
  86         /* Note that the cgroup.procs might contain duplicates! See
  87          * cgroups.txt for details. */
  88
  89         assert(f);
  90         assert(_pid);
  91
  92         errno = 0;
  93         if (fscanf(f, "%lu", &ul) != 1) {
  94
  95                 if (feof(f))
  96                         return 0;
  97
  98                 return errno > 0 ? -errno : -EIO;
  99         }
 100
 101         if (ul <= 0)
 102                 return -EIO;
 103
 104         *_pid = (pid_t) ul;
 105         return 1;
 106 }
 107
 108 int cg_read_event(
 109                 const char *controller,
 110                 const char *path,
 111                 const char *event,
 112                 char **val) {
 113
 114         _cleanup_free_ char *events = NULL, *content = NULL;
 115         char *p, *line;
 116         int r;
 117
 118         r = cg_get_path(controller, path, "cgroup.events", &events);
 119         if (r < 0)
 120                 return r;
 121
 122         r = read_full_file(events, &content, NULL);
 123         if (r < 0)
 124                 return r;
 125
 126         p = content;
 127         while ((line = strsep(&p, "\n"))) {
 128                 char *key;
 129
 130                 key = strsep(&line, " ");
 131                 if (!key || !line)
 132                         return -EINVAL;
 133
 134                 if (strcmp(key, event))
 135                         continue;
 136
 137                 *val = strdup(line);
 138                 return 0;
 139         }
 140
 141         return -ENOENT;
 142 }
 143
 144 bool cg_ns_supported(void) {
 145         static thread_local int enabled = -1;
 146
 147         if (enabled >= 0)
 148                 return enabled;
 149
 150         if (access("/proc/self/ns/cgroup", F_OK) == 0)
 151                 enabled = 1;
 152         else
 153                 enabled = 0;
 154
 155         return enabled;
 156 }
 157
 158 int cg_enumerate_subgroups(const char *controller, const char *path, DIR **_d) {
 159         _cleanup_free_ char *fs = NULL;
 160         int r;
 161         DIR *d;
 162
 163         assert(_d);
 164
 165         /* This is not recursive! */
 166
 167         r = cg_get_path(controller, path, NULL, &fs);
 168         if (r < 0)
 169                 return r;
 170
 171         d = opendir(fs);
 172         if (!d)
 173                 return -errno;
 174
 175         *_d = d;
 176         return 0;
 177 }
 178
 179 int cg_read_subgroup(DIR *d, char **fn) {
 180         struct dirent *de;
 181
 182         assert(d);
 183         assert(fn);
 184
 185         FOREACH_DIRENT_ALL(de, d, return -errno) {
 186                 char *b;
 187
 188                 if (de->d_type != DT_DIR)
 189                         continue;
 190
 191                 if (dot_or_dot_dot(de->d_name))
 192                         continue;
 193
 194                 b = strdup(de->d_name);
 195                 if (!b)
 196                         return -ENOMEM;
 197
 198                 *fn = b;
 199                 return 1;
 200         }
 201
 202         return 0;
 203 }
 204
 205 int cg_rmdir(const char *controller, const char *path) {
 206         _cleanup_free_ char *p = NULL;
 207         int r;
 208
 209         r = cg_get_path(controller, path, NULL, &p);
 210         if (r < 0)
 211                 return r;
 212
 213         r = rmdir(p);
 214         if (r < 0 && errno != ENOENT)
 215                 return -errno;
 216
 217         r = cg_hybrid_unified();
 218         if (r < 0)
 219                 return r;
 220         if (r == 0)
 221                 return 0;
 222
 223         if (streq(controller, SYSTEMD_CGROUP_CONTROLLER)) {
 224                 r = cg_rmdir(SYSTEMD_CGROUP_CONTROLLER_LEGACY, path);
 225                 if (r < 0)
 226                         log_warning_errno(r, "Failed to remove compat systemd cgroup %s: %m", path);
 227         }
 228
 229         return 0;
 230 }
 231
 232 int cg_kill(
 233                 const char *controller,
 234                 const char *path,
 235                 int sig,
 236                 CGroupFlags flags,
 237                 Set *s,
 238                 cg_kill_log_func_t log_kill,
 239                 void *userdata) {
 240
 241         _cleanup_set_free_ Set *allocated_set = NULL;
 242         bool done = false;
 243         int r, ret = 0;
 244         pid_t my_pid;
 245
 246         assert(sig >= 0);
 247
 248          /* Don't send SIGCONT twice. Also, SIGKILL always works even when process is suspended, hence don't send
 249           * SIGCONT on SIGKILL. */
 250         if (IN_SET(sig, SIGCONT, SIGKILL))
 251                 flags &= ~CGROUP_SIGCONT;
 252
 253         /* This goes through the tasks list and kills them all. This
 254          * is repeated until no further processes are added to the
 255          * tasks list, to properly handle forking processes */
 256
 257         if (!s) {
 258                 s = allocated_set = set_new(NULL);
 259                 if (!s)
 260                         return -ENOMEM;
 261         }
 262
 263         my_pid = getpid_cached();
 264
 265         do {
 266                 _cleanup_fclose_ FILE *f = NULL;
 267                 pid_t pid = 0;
 268                 done = true;
 269
 270                 r = cg_enumerate_processes(controller, path, &f);
 271                 if (r < 0) {
 272                         if (ret >= 0 && r != -ENOENT)
 273                                 return r;
 274
 275                         return ret;
 276                 }
 277
 278                 while ((r = cg_read_pid(f, &pid)) > 0) {
 279
 280                         if ((flags & CGROUP_IGNORE_SELF) && pid == my_pid)
 281                                 continue;
 282
 283                         if (set_get(s, PID_TO_PTR(pid)) == PID_TO_PTR(pid))
 284                                 continue;
 285
 286                         if (log_kill)
 287                                 log_kill(pid, sig, userdata);
 288
 289                         /* If we haven't killed this process yet, kill
 290                          * it */
 291                         if (kill(pid, sig) < 0) {
 292                                 if (ret >= 0 && errno != ESRCH)
 293                                         ret = -errno;
 294                         } else {
 295                                 if (flags & CGROUP_SIGCONT)
 296                                         (void) kill(pid, SIGCONT);
 297
 298                                 if (ret == 0)
 299                                         ret = 1;
 300                         }
 301
 302                         done = false;
 303
 304                         r = set_put(s, PID_TO_PTR(pid));
 305                         if (r < 0) {
 306                                 if (ret >= 0)
 307                                         return r;
 308
 309                                 return ret;
 310                         }
 311                 }
 312
 313                 if (r < 0) {
 314                         if (ret >= 0)
 315                                 return r;
 316
 317                         return ret;
 318                 }
 319
 320                 /* To avoid racing against processes which fork
 321                  * quicker than we can kill them we repeat this until
 322                  * no new pids need to be killed. */
 323
 324         } while (!done);
 325
 326         return ret;
 327 }
 328
 329 int cg_kill_recursive(
 330                 const char *controller,
 331                 const char *path,
 332                 int sig,
 333                 CGroupFlags flags,
 334                 Set *s,
 335                 cg_kill_log_func_t log_kill,
 336                 void *userdata) {
 337
 338         _cleanup_set_free_ Set *allocated_set = NULL;
 339         _cleanup_closedir_ DIR *d = NULL;
 340         int r, ret;
 341         char *fn;
 342
 343         assert(path);
 344         assert(sig >= 0);
 345
 346         if (!s) {
 347                 s = allocated_set = set_new(NULL);
 348                 if (!s)
 349                         return -ENOMEM;
 350         }
 351
 352         ret = cg_kill(controller, path, sig, flags, s, log_kill, userdata);
 353
 354         r = cg_enumerate_subgroups(controller, path, &d);
 355         if (r < 0) {
 356                 if (ret >= 0 && r != -ENOENT)
 357                         return r;
 358
 359                 return ret;
 360         }
 361
 362         while ((r = cg_read_subgroup(d, &fn)) > 0) {
 363                 _cleanup_free_ char *p = NULL;
 364
 365                 p = strjoin(path, "/", fn);
 366                 free(fn);
 367                 if (!p)
 368                         return -ENOMEM;
 369
 370                 r = cg_kill_recursive(controller, p, sig, flags, s, log_kill, userdata);
 371                 if (r != 0 && ret >= 0)
 372                         ret = r;
 373         }
 374         if (ret >= 0 && r < 0)
 375                 ret = r;
 376
 377         if (flags & CGROUP_REMOVE) {
 378                 r = cg_rmdir(controller, path);
 379                 if (r < 0 && ret >= 0 && !IN_SET(r, -ENOENT, -EBUSY))
 380                         return r;
 381         }
 382
 383         return ret;
 384 }
 385
 386 int cg_migrate(
 387                 const char *cfrom,
 388                 const char *pfrom,
 389                 const char *cto,
 390                 const char *pto,
 391                 CGroupFlags flags) {
 392
 393         bool done = false;
 394         _cleanup_set_free_ Set *s = NULL;
 395         int r, ret = 0;
 396         pid_t my_pid;
 397
 398         assert(cfrom);
 399         assert(pfrom);
 400         assert(cto);
 401         assert(pto);
 402
 403         s = set_new(NULL);
 404         if (!s)
 405                 return -ENOMEM;
 406
 407         my_pid = getpid_cached();
 408
 409         do {
 410                 _cleanup_fclose_ FILE *f = NULL;
 411                 pid_t pid = 0;
 412                 done = true;
 413
 414                 r = cg_enumerate_processes(cfrom, pfrom, &f);
 415                 if (r < 0) {
 416                         if (ret >= 0 && r != -ENOENT)
 417                                 return r;
 418
 419                         return ret;
 420                 }
 421
 422                 while ((r = cg_read_pid(f, &pid)) > 0) {
 423
 424                         /* This might do weird stuff if we aren't a
 425                          * single-threaded program. However, we
 426                          * luckily know we are not */
 427                         if ((flags & CGROUP_IGNORE_SELF) && pid == my_pid)
 428                                 continue;
 429
 430                         if (set_get(s, PID_TO_PTR(pid)) == PID_TO_PTR(pid))
 431                                 continue;
 432
 433                         /* Ignore kernel threads. Since they can only
 434                          * exist in the root cgroup, we only check for
 435                          * them there. */
 436                         if (cfrom &&
 437                             (isempty(pfrom) || path_equal(pfrom, "/")) &&
 438                             is_kernel_thread(pid) > 0)
 439                                 continue;
 440
 441                         r = cg_attach(cto, pto, pid);
 442                         if (r < 0) {
 443                                 if (ret >= 0 && r != -ESRCH)
 444                                         ret = r;
 445                         } else if (ret == 0)
 446                                 ret = 1;
 447
 448                         done = false;
 449
 450                         r = set_put(s, PID_TO_PTR(pid));
 451                         if (r < 0) {
 452                                 if (ret >= 0)
 453                                         return r;
 454
 455                                 return ret;
 456                         }
 457                 }
 458
 459                 if (r < 0) {
 460                         if (ret >= 0)
 461                                 return r;
 462
 463                         return ret;
 464                 }
 465         } while (!done);
 466
 467         return ret;
 468 }
 469
 470 int cg_migrate_recursive(
 471                 const char *cfrom,
 472                 const char *pfrom,
 473                 const char *cto,
 474                 const char *pto,
 475                 CGroupFlags flags) {
 476
 477         _cleanup_closedir_ DIR *d = NULL;
 478         int r, ret = 0;
 479         char *fn;
 480
 481         assert(cfrom);
 482         assert(pfrom);
 483         assert(cto);
 484         assert(pto);
 485
 486         ret = cg_migrate(cfrom, pfrom, cto, pto, flags);
 487
 488         r = cg_enumerate_subgroups(cfrom, pfrom, &d);
 489         if (r < 0) {
 490                 if (ret >= 0 && r != -ENOENT)
 491                         return r;
 492
 493                 return ret;
 494         }
 495
 496         while ((r = cg_read_subgroup(d, &fn)) > 0) {
 497                 _cleanup_free_ char *p = NULL;
 498
 499                 p = strjoin(pfrom, "/", fn);
 500                 free(fn);
 501                 if (!p)
 502                         return -ENOMEM;
 503
 504                 r = cg_migrate_recursive(cfrom, p, cto, pto, flags);
 505                 if (r != 0 && ret >= 0)
 506                         ret = r;
 507         }
 508
 509         if (r < 0 && ret >= 0)
 510                 ret = r;
 511
 512         if (flags & CGROUP_REMOVE) {
 513                 r = cg_rmdir(cfrom, pfrom);
 514                 if (r < 0 && ret >= 0 && !IN_SET(r, -ENOENT, -EBUSY))
 515                         return r;
 516         }
 517
 518         return ret;
 519 }
 520
 521 int cg_migrate_recursive_fallback(
 522                 const char *cfrom,
 523                 const char *pfrom,
 524                 const char *cto,
 525                 const char *pto,
 526                 CGroupFlags flags) {
 527
 528         int r;
 529
 530         assert(cfrom);
 531         assert(pfrom);
 532         assert(cto);
 533         assert(pto);
 534
 535         r = cg_migrate_recursive(cfrom, pfrom, cto, pto, flags);
 536         if (r < 0) {
 537                 char prefix[strlen(pto) + 1];
 538
 539                 /* This didn't work? Then let's try all prefixes of the destination */
 540
 541                 PATH_FOREACH_PREFIX(prefix, pto) {
 542                         int q;
 543
 544                         q = cg_migrate_recursive(cfrom, pfrom, cto, prefix, flags);
 545                         if (q >= 0)
 546                                 return q;
 547                 }
 548         }
 549
 550         return r;
 551 }
 552
 553 static const char *controller_to_dirname(const char *controller) {
 554         const char *e;
 555
 556         assert(controller);
 557
 558         /* Converts a controller name to the directory name below
 559          * /sys/fs/cgroup/ we want to mount it to. Effectively, this
 560          * just cuts off the name= prefixed used for named
 561          * hierarchies, if it is specified. */
 562
 563         if (streq(controller, SYSTEMD_CGROUP_CONTROLLER)) {
 564                 if (cg_hybrid_unified() > 0)
 565                         controller = SYSTEMD_CGROUP_CONTROLLER_HYBRID;
 566                 else
 567                         controller = SYSTEMD_CGROUP_CONTROLLER_LEGACY;
 568         }
 569
 570         e = startswith(controller, "name=");
 571         if (e)
 572                 return e;
 573
 574         return controller;
 575 }
 576
 577 static int join_path_legacy(const char *controller, const char *path, const char *suffix, char **fs) {
 578         const char *dn;
 579         char *t = NULL;
 580
 581         assert(fs);
 582         assert(controller);
 583
 584         dn = controller_to_dirname(controller);
 585
 586         if (isempty(path) && isempty(suffix))
 587                 t = strappend("/sys/fs/cgroup/", dn);
 588         else if (isempty(path))
 589                 t = strjoin("/sys/fs/cgroup/", dn, "/", suffix);
 590         else if (isempty(suffix))
 591                 t = strjoin("/sys/fs/cgroup/", dn, "/", path);
 592         else
 593                 t = strjoin("/sys/fs/cgroup/", dn, "/", path, "/", suffix);
 594         if (!t)
 595                 return -ENOMEM;
 596
 597         *fs = t;
 598         return 0;
 599 }
 600
 601 static int join_path_unified(const char *path, const char *suffix, char **fs) {
 602         char *t;
 603
 604         assert(fs);
 605
 606         if (isempty(path) && isempty(suffix))
 607                 t = strdup("/sys/fs/cgroup");
 608         else if (isempty(path))
 609                 t = strappend("/sys/fs/cgroup/", suffix);
 610         else if (isempty(suffix))
 611                 t = strappend("/sys/fs/cgroup/", path);
 612         else
 613                 t = strjoin("/sys/fs/cgroup/", path, "/", suffix);
 614         if (!t)
 615                 return -ENOMEM;
 616
 617         *fs = t;
 618         return 0;
 619 }
 620
 621 int cg_get_path(const char *controller, const char *path, const char *suffix, char **fs) {
 622         int r;
 623
 624         assert(fs);
 625
 626         if (!controller) {
 627                 char *t;
 628
 629                 /* If no controller is specified, we return the path
 630                  * *below* the controllers, without any prefix. */
 631
 632                 if (!path && !suffix)
 633                         return -EINVAL;
 634
 635                 if (!suffix)
 636                         t = strdup(path);
 637                 else if (!path)
 638                         t = strdup(suffix);
 639                 else
 640                         t = strjoin(path, "/", suffix);
 641                 if (!t)
 642                         return -ENOMEM;
 643
 644                 *fs = path_kill_slashes(t);
 645                 return 0;
 646         }
 647
 648         if (!cg_controller_is_valid(controller))
 649                 return -EINVAL;
 650
 651         r = cg_all_unified();
 652         if (r < 0)
 653                 return r;
 654         if (r > 0)
 655                 r = join_path_unified(path, suffix, fs);
 656         else
 657                 r = join_path_legacy(controller, path, suffix, fs);
 658         if (r < 0)
 659                 return r;
 660
 661         path_kill_slashes(*fs);
 662         return 0;
 663 }
 664
 665 static int controller_is_accessible(const char *controller) {
 666         int r;
 667
 668         assert(controller);
 669
 670         /* Checks whether a specific controller is accessible,
 671          * i.e. its hierarchy mounted. In the unified hierarchy all
 672          * controllers are considered accessible, except for the named
 673          * hierarchies */
 674
 675         if (!cg_controller_is_valid(controller))
 676                 return -EINVAL;
 677
 678         r = cg_all_unified();
 679         if (r < 0)
 680                 return r;
 681         if (r > 0) {
 682                 /* We don't support named hierarchies if we are using
 683                  * the unified hierarchy. */
 684
 685                 if (streq(controller, SYSTEMD_CGROUP_CONTROLLER))
 686                         return 0;
 687
 688                 if (startswith(controller, "name="))
 689                         return -EOPNOTSUPP;
 690
 691         } else {
 692                 const char *cc, *dn;
 693
 694                 dn = controller_to_dirname(controller);
 695                 cc = strjoina("/sys/fs/cgroup/", dn);
 696
 697                 if (laccess(cc, F_OK) < 0)
 698                         return -errno;
 699         }
 700
 701         return 0;
 702 }
 703
 704 int cg_get_path_and_check(const char *controller, const char *path, const char *suffix, char **fs) {
 705         int r;
 706
 707         assert(controller);
 708         assert(fs);
 709
 710         /* Check if the specified controller is actually accessible */
 711         r = controller_is_accessible(controller);
 712         if (r < 0)
 713                 return r;
 714
 715         return cg_get_path(controller, path, suffix, fs);
 716 }
 717
 718 static int trim_cb(const char *path, const struct stat *sb, int typeflag, struct FTW *ftwbuf) {
 719         assert(path);
 720         assert(sb);
 721         assert(ftwbuf);
 722
 723         if (typeflag != FTW_DP)
 724                 return 0;
 725
 726         if (ftwbuf->level < 1)
 727                 return 0;
 728
 729         (void) rmdir(path);
 730         return 0;
 731 }
 732
 733 int cg_trim(const char *controller, const char *path, bool delete_root) {
 734         _cleanup_free_ char *fs = NULL;
 735         int r = 0, q;
 736
 737         assert(path);
 738
 739         r = cg_get_path(controller, path, NULL, &fs);
 740         if (r < 0)
 741                 return r;
 742
 743         errno = 0;
 744         if (nftw(fs, trim_cb, 64, FTW_DEPTH|FTW_MOUNT|FTW_PHYS) != 0) {
 745                 if (errno == ENOENT)
 746                         r = 0;
 747                 else if (errno > 0)
 748                         r = -errno;
 749                 else
 750                         r = -EIO;
 751         }
 752
 753         if (delete_root) {
 754                 if (rmdir(fs) < 0 && errno != ENOENT)
 755                         return -errno;
 756         }
 757
 758         q = cg_hybrid_unified();
 759         if (q < 0)
 760                 return q;
 761         if (q > 0 && streq(controller, SYSTEMD_CGROUP_CONTROLLER)) {
 762                 q = cg_trim(SYSTEMD_CGROUP_CONTROLLER_LEGACY, path, delete_root);
 763                 if (q < 0)
 764                         log_warning_errno(q, "Failed to trim compat systemd cgroup %s: %m", path);
 765         }
 766
 767         return r;
 768 }
 769
 770 int cg_create(const char *controller, const char *path) {
 771         _cleanup_free_ char *fs = NULL;
 772         int r;
 773
 774         r = cg_get_path_and_check(controller, path, NULL, &fs);
 775         if (r < 0)
 776                 return r;
 777
 778         r = mkdir_parents(fs, 0755);
 779         if (r < 0)
 780                 return r;
 781
 782         r = mkdir_errno_wrapper(fs, 0755);
 783         if (r == -EEXIST)
 784                 return 0;
 785         if (r < 0)
 786                 return r;
 787
 788         r = cg_hybrid_unified();
 789         if (r < 0)
 790                 return r;
 791
 792         if (r > 0 && streq(controller, SYSTEMD_CGROUP_CONTROLLER)) {
 793                 r = cg_create(SYSTEMD_CGROUP_CONTROLLER_LEGACY, path);
 794                 if (r < 0)
 795                         log_warning_errno(r, "Failed to create compat systemd cgroup %s: %m", path);
 796         }
 797
 798         return 1;
 799 }
 800
 801 int cg_create_and_attach(const char *controller, const char *path, pid_t pid) {
 802         int r, q;
 803
 804         assert(pid >= 0);
 805
 806         r = cg_create(controller, path);
 807         if (r < 0)
 808                 return r;
 809
 810         q = cg_attach(controller, path, pid);
 811         if (q < 0)
 812                 return q;
 813
 814         /* This does not remove the cgroup on failure */
 815         return r;
 816 }
 817
 818 int cg_attach(const char *controller, const char *path, pid_t pid) {
 819         _cleanup_free_ char *fs = NULL;
 820         char c[DECIMAL_STR_MAX(pid_t) + 2];
 821         int r;
 822
 823         assert(path);
 824         assert(pid >= 0);
 825
 826         r = cg_get_path_and_check(controller, path, "cgroup.procs", &fs);
 827         if (r < 0)
 828                 return r;
 829
 830         if (pid == 0)
 831                 pid = getpid_cached();
 832
 833         xsprintf(c, PID_FMT "\n", pid);
 834
 835         r = write_string_file(fs, c, 0);
 836         if (r < 0)
 837                 return r;
 838
 839         r = cg_hybrid_unified();
 840         if (r < 0)
 841                 return r;
 842
 843         if (r > 0 && streq(controller, SYSTEMD_CGROUP_CONTROLLER)) {
 844                 r = cg_attach(SYSTEMD_CGROUP_CONTROLLER_LEGACY, path, pid);
 845                 if (r < 0)
 846                         log_warning_errno(r, "Failed to attach "PID_FMT" to compat systemd cgroup %s: %m", pid, path);
 847         }
 848
 849         return 0;
 850 }
 851
 852 int cg_attach_fallback(const char *controller, const char *path, pid_t pid) {
 853         int r;
 854
 855         assert(controller);
 856         assert(path);
 857         assert(pid >= 0);
 858
 859         r = cg_attach(controller, path, pid);
 860         if (r < 0) {
 861                 char prefix[strlen(path) + 1];
 862
 863                 /* This didn't work? Then let's try all prefixes of
 864                  * the destination */
 865
 866                 PATH_FOREACH_PREFIX(prefix, path) {
 867                         int q;
 868
 869                         q = cg_attach(controller, prefix, pid);
 870                         if (q >= 0)
 871                                 return q;
 872                 }
 873         }
 874
 875         return r;
 876 }
 877
 878 int cg_set_access(
 879                 const char *controller,
 880                 const char *path,
 881                 uid_t uid,
 882                 gid_t gid) {
 883
 884         struct Attribute {
 885                 const char *name;
 886                 bool fatal;
 887         };
 888
 889         /* cgroupsv1, aka legacy/non-unified */
 890         static const struct Attribute legacy_attributes[] = {
 891                 { "cgroup.procs",           true  },
 892                 { "tasks",                  false },
 893                 { "cgroup.clone_children",  false },
 894                 {},
 895         };
 896
 897         /* cgroupsv2, aka unified */
 898         static const struct Attribute unified_attributes[] = {
 899                 { "cgroup.procs",           true  },
 900                 { "cgroup.subtree_control", true  },
 901                 { "cgroup.threads",         false },
 902                 {},
 903         };
 904
 905         static const struct Attribute* const attributes[] = {
 906                 [false] = legacy_attributes,
 907                 [true]  = unified_attributes,
 908         };
 909
 910         _cleanup_free_ char *fs = NULL;
 911         const struct Attribute *i;
 912         int r, unified;
 913
 914         assert(path);
 915
 916         if (uid == UID_INVALID && gid == GID_INVALID)
 917                 return 0;
 918
 919         unified = cg_unified_controller(controller);
 920         if (unified < 0)
 921                 return unified;
 922
 923         /* Configure access to the cgroup itself */
 924         r = cg_get_path(controller, path, NULL, &fs);
 925         if (r < 0)
 926                 return r;
 927
 928         r = chmod_and_chown(fs, 0755, uid, gid);
 929         if (r < 0)
 930                 return r;
 931
 932         /* Configure access to the cgroup's attributes */
 933         for (i = attributes[unified]; i->name; i++) {
 934                 fs = mfree(fs);
 935
 936                 r = cg_get_path(controller, path, i->name, &fs);
 937                 if (r < 0)
 938                         return r;
 939
 940                 r = chmod_and_chown(fs, 0644, uid, gid);
 941                 if (r < 0) {
 942                         if (i->fatal)
 943                                 return r;
 944
 945                         log_debug_errno(r, "Failed to set access on cgroup %s, ignoring: %m", fs);
 946                 }
 947         }
 948
 949         if (streq(controller, SYSTEMD_CGROUP_CONTROLLER)) {
 950                 r = cg_hybrid_unified();
 951                 if (r < 0)
 952                         return r;
 953                 if (r > 0) {
 954                         /* Always propagate access mode from unified to legacy controller */
 955                         r = cg_set_access(SYSTEMD_CGROUP_CONTROLLER_LEGACY, path, uid, gid);
 956                         if (r < 0)
 957                                 log_debug_errno(r, "Failed to set access on compatibility systemd cgroup %s, ignoring: %m", path);
 958                 }
 959         }
 960
 961         return 0;
 962 }
 963
 964 int cg_set_xattr(const char *controller, const char *path, const char *name, const void *value, size_t size, int flags) {
 965         _cleanup_free_ char *fs = NULL;
 966         int r;
 967
 968         assert(path);
 969         assert(name);
 970         assert(value || size <= 0);
 971
 972         r = cg_get_path(controller, path, NULL, &fs);
 973         if (r < 0)
 974                 return r;
 975
 976         if (setxattr(fs, name, value, size, flags) < 0)
 977                 return -errno;
 978
 979         return 0;
 980 }
 981
 982 int cg_get_xattr(const char *controller, const char *path, const char *name, void *value, size_t size) {
 983         _cleanup_free_ char *fs = NULL;
 984         ssize_t n;
 985         int r;
 986
 987         assert(path);
 988         assert(name);
 989
 990         r = cg_get_path(controller, path, NULL, &fs);
 991         if (r < 0)
 992                 return r;
 993
 994         n = getxattr(fs, name, value, size);
 995         if (n < 0)
 996                 return -errno;
 997
 998         return (int) n;
 999 }
1000
1001 int cg_pid_get_path(const char *controller, pid_t pid, char **path) {
1002         _cleanup_fclose_ FILE *f = NULL;
1003         char line[LINE_MAX];
1004         const char *fs, *controller_str;
1005         size_t cs = 0;
1006         int unified;
1007
1008         assert(path);
1009         assert(pid >= 0);
1010
1011         if (controller) {
1012                 if (!cg_controller_is_valid(controller))
1013                         return -EINVAL;
1014         } else
1015                 controller = SYSTEMD_CGROUP_CONTROLLER;
1016
1017         unified = cg_unified_controller(controller);
1018         if (unified < 0)
1019                 return unified;
1020         if (unified == 0) {
1021                 if (streq(controller, SYSTEMD_CGROUP_CONTROLLER))
1022                         controller_str = SYSTEMD_CGROUP_CONTROLLER_LEGACY;
1023                 else
1024                         controller_str = controller;
1025
1026                 cs = strlen(controller_str);
1027         }
1028
1029         fs = procfs_file_alloca(pid, "cgroup");
1030         f = fopen(fs, "re");
1031         if (!f)
1032                 return errno == ENOENT ? -ESRCH : -errno;
1033
1034         (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
1035
1036         FOREACH_LINE(line, f, return -errno) {
1037                 char *e, *p;
1038
1039                 truncate_nl(line);
1040
1041                 if (unified) {
1042                         e = startswith(line, "0:");
1043                         if (!e)
1044                                 continue;
1045
1046                         e = strchr(e, ':');
1047                         if (!e)
1048                                 continue;
1049                 } else {
1050                         char *l;
1051                         size_t k;
1052                         const char *word, *state;
1053                         bool found = false;
1054
1055                         l = strchr(line, ':');
1056                         if (!l)
1057                                 continue;
1058
1059                         l++;
1060                         e = strchr(l, ':');
1061                         if (!e)
1062                                 continue;
1063
1064                         *e = 0;
1065                         FOREACH_WORD_SEPARATOR(word, k, l, ",", state)
1066                                 if (k == cs && memcmp(word, controller_str, cs) == 0) {
1067                                         found = true;
1068                                         break;
1069                                 }
1070                         if (!found)
1071                                 continue;
1072                 }
1073
1074                 p = strdup(e + 1);
1075                 if (!p)
1076                         return -ENOMEM;
1077
1078                 /* Truncate suffix indicating the process is a zombie */
1079                 e = endswith(p, " (deleted)");
1080                 if (e)
1081                         *e = 0;
1082
1083                 *path = p;
1084                 return 0;
1085         }
1086
1087         return -ENODATA;
1088 }
1089
1090 int cg_install_release_agent(const char *controller, const char *agent) {
1091         _cleanup_free_ char *fs = NULL, *contents = NULL;
1092         const char *sc;
1093         int r;
1094
1095         assert(agent);
1096
1097         r = cg_unified_controller(controller);
1098         if (r < 0)
1099                 return r;
1100         if (r > 0) /* doesn't apply to unified hierarchy */
1101                 return -EOPNOTSUPP;
1102
1103         r = cg_get_path(controller, NULL, "release_agent", &fs);
1104         if (r < 0)
1105                 return r;
1106
1107         r = read_one_line_file(fs, &contents);
1108         if (r < 0)
1109                 return r;
1110
1111         sc = strstrip(contents);
1112         if (isempty(sc)) {
1113                 r = write_string_file(fs, agent, 0);
1114                 if (r < 0)
1115                         return r;
1116         } else if (!path_equal(sc, agent))
1117                 return -EEXIST;
1118
1119         fs = mfree(fs);
1120         r = cg_get_path(controller, NULL, "notify_on_release", &fs);
1121         if (r < 0)
1122                 return r;
1123
1124         contents = mfree(contents);
1125         r = read_one_line_file(fs, &contents);
1126         if (r < 0)
1127                 return r;
1128
1129         sc = strstrip(contents);
1130         if (streq(sc, "0")) {
1131                 r = write_string_file(fs, "1", 0);
1132                 if (r < 0)
1133                         return r;
1134
1135                 return 1;
1136         }
1137
1138         if (!streq(sc, "1"))
1139                 return -EIO;
1140
1141         return 0;
1142 }
1143
1144 int cg_uninstall_release_agent(const char *controller) {
1145         _cleanup_free_ char *fs = NULL;
1146         int r;
1147
1148         r = cg_unified_controller(controller);
1149         if (r < 0)
1150                 return r;
1151         if (r > 0) /* Doesn't apply to unified hierarchy */
1152                 return -EOPNOTSUPP;
1153
1154         r = cg_get_path(controller, NULL, "notify_on_release", &fs);
1155         if (r < 0)
1156                 return r;
1157
1158         r = write_string_file(fs, "0", 0);
1159         if (r < 0)
1160                 return r;
1161
1162         fs = mfree(fs);
1163
1164         r = cg_get_path(controller, NULL, "release_agent", &fs);
1165         if (r < 0)
1166                 return r;
1167
1168         r = write_string_file(fs, "", 0);
1169         if (r < 0)
1170                 return r;
1171
1172         return 0;
1173 }
1174
1175 int cg_is_empty(const char *controller, const char *path) {
1176         _cleanup_fclose_ FILE *f = NULL;
1177         pid_t pid;
1178         int r;
1179
1180         assert(path);
1181
1182         r = cg_enumerate_processes(controller, path, &f);
1183         if (r == -ENOENT)
1184                 return 1;
1185         if (r < 0)
1186                 return r;
1187
1188         r = cg_read_pid(f, &pid);
1189         if (r < 0)
1190                 return r;
1191
1192         return r == 0;
1193 }
1194
1195 int cg_is_empty_recursive(const char *controller, const char *path) {
1196         int r;
1197
1198         assert(path);
1199
1200         /* The root cgroup is always populated */
1201         if (controller && (isempty(path) || path_equal(path, "/")))
1202                 return false;
1203
1204         r = cg_unified_controller(controller);
1205         if (r < 0)
1206                 return r;
1207         if (r > 0) {
1208                 _cleanup_free_ char *t = NULL;
1209
1210                 /* On the unified hierarchy we can check empty state
1211                  * via the "populated" attribute of "cgroup.events". */
1212
1213                 r = cg_read_event(controller, path, "populated", &t);
1214                 if (r < 0)
1215                         return r;
1216
1217                 return streq(t, "0");
1218         } else {
1219                 _cleanup_closedir_ DIR *d = NULL;
1220                 char *fn;
1221
1222                 r = cg_is_empty(controller, path);
1223                 if (r <= 0)
1224                         return r;
1225
1226                 r = cg_enumerate_subgroups(controller, path, &d);
1227                 if (r == -ENOENT)
1228                         return 1;
1229                 if (r < 0)
1230                         return r;
1231
1232                 while ((r = cg_read_subgroup(d, &fn)) > 0) {
1233                         _cleanup_free_ char *p = NULL;
1234
1235                         p = strjoin(path, "/", fn);
1236                         free(fn);
1237                         if (!p)
1238                                 return -ENOMEM;
1239
1240                         r = cg_is_empty_recursive(controller, p);
1241                         if (r <= 0)
1242                                 return r;
1243                 }
1244                 if (r < 0)
1245                         return r;
1246
1247                 return true;
1248         }
1249 }
1250
1251 int cg_split_spec(const char *spec, char **controller, char **path) {
1252         char *t = NULL, *u = NULL;
1253         const char *e;
1254
1255         assert(spec);
1256
1257         if (*spec == '/') {
1258                 if (!path_is_normalized(spec))
1259                         return -EINVAL;
1260
1261                 if (path) {
1262                         t = strdup(spec);
1263                         if (!t)
1264                                 return -ENOMEM;
1265
1266                         *path = path_kill_slashes(t);
1267                 }
1268
1269                 if (controller)
1270                         *controller = NULL;
1271
1272                 return 0;
1273         }
1274
1275         e = strchr(spec, ':');
1276         if (!e) {
1277                 if (!cg_controller_is_valid(spec))
1278                         return -EINVAL;
1279
1280                 if (controller) {
1281                         t = strdup(spec);
1282                         if (!t)
1283                                 return -ENOMEM;
1284
1285                         *controller = t;
1286                 }
1287
1288                 if (path)
1289                         *path = NULL;
1290
1291                 return 0;
1292         }
1293
1294         t = strndup(spec, e-spec);
1295         if (!t)
1296                 return -ENOMEM;
1297         if (!cg_controller_is_valid(t)) {
1298                 free(t);
1299                 return -EINVAL;
1300         }
1301
1302         if (isempty(e+1))
1303                 u = NULL;
1304         else {
1305                 u = strdup(e+1);
1306                 if (!u) {
1307                         free(t);
1308                         return -ENOMEM;
1309                 }
1310
1311                 if (!path_is_normalized(u) ||
1312                     !path_is_absolute(u)) {
1313                         free(t);
1314                         free(u);
1315                         return -EINVAL;
1316                 }
1317
1318                 path_kill_slashes(u);
1319         }
1320
1321         if (controller)
1322                 *controller = t;
1323         else
1324                 free(t);
1325
1326         if (path)
1327                 *path = u;
1328         else
1329                 free(u);
1330
1331         return 0;
1332 }
1333
1334 int cg_mangle_path(const char *path, char **result) {
1335         _cleanup_free_ char *c = NULL, *p = NULL;
1336         char *t;
1337         int r;
1338
1339         assert(path);
1340         assert(result);
1341
1342         /* First, check if it already is a filesystem path */
1343         if (path_startswith(path, "/sys/fs/cgroup")) {
1344
1345                 t = strdup(path);
1346                 if (!t)
1347                         return -ENOMEM;
1348
1349                 *result = path_kill_slashes(t);
1350                 return 0;
1351         }
1352
1353         /* Otherwise, treat it as cg spec */
1354         r = cg_split_spec(path, &c, &p);
1355         if (r < 0)
1356                 return r;
1357
1358         return cg_get_path(c ?: SYSTEMD_CGROUP_CONTROLLER, p ?: "/", NULL, result);
1359 }
1360
1361 int cg_get_root_path(char **path) {
1362         char *p, *e;
1363         int r;
1364
1365         assert(path);
1366
1367         r = cg_pid_get_path(SYSTEMD_CGROUP_CONTROLLER, 1, &p);
1368         if (r < 0)
1369                 return r;
1370
1371         e = endswith(p, "/" SPECIAL_INIT_SCOPE);
1372         if (!e)
1373                 e = endswith(p, "/" SPECIAL_SYSTEM_SLICE); /* legacy */
1374         if (!e)
1375                 e = endswith(p, "/system"); /* even more legacy */
1376         if (e)
1377                 *e = 0;
1378
1379         *path = p;
1380         return 0;
1381 }
1382
1383 int cg_shift_path(const char *cgroup, const char *root, const char **shifted) {
1384         _cleanup_free_ char *rt = NULL;
1385         char *p;
1386         int r;
1387
1388         assert(cgroup);
1389         assert(shifted);
1390
1391         if (!root) {
1392                 /* If the root was specified let's use that, otherwise
1393                  * let's determine it from PID 1 */
1394
1395                 r = cg_get_root_path(&rt);
1396                 if (r < 0)
1397                         return r;
1398
1399                 root = rt;
1400         }
1401
1402         p = path_startswith(cgroup, root);
1403         if (p && p > cgroup)
1404                 *shifted = p - 1;
1405         else
1406                 *shifted = cgroup;
1407
1408         return 0;
1409 }
1410
1411 int cg_pid_get_path_shifted(pid_t pid, const char *root, char **cgroup) {
1412         _cleanup_free_ char *raw = NULL;
1413         const char *c;
1414         int r;
1415
1416         assert(pid >= 0);
1417         assert(cgroup);
1418
1419         r = cg_pid_get_path(SYSTEMD_CGROUP_CONTROLLER, pid, &raw);
1420         if (r < 0)
1421                 return r;
1422
1423         r = cg_shift_path(raw, root, &c);
1424         if (r < 0)
1425                 return r;
1426
1427         if (c == raw) {
1428                 *cgroup = raw;
1429                 raw = NULL;
1430         } else {
1431                 char *n;
1432
1433                 n = strdup(c);
1434                 if (!n)
1435                         return -ENOMEM;
1436
1437                 *cgroup = n;
1438         }
1439
1440         return 0;
1441 }
1442
1443 int cg_path_decode_unit(const char *cgroup, char **unit) {
1444         char *c, *s;
1445         size_t n;
1446
1447         assert(cgroup);
1448         assert(unit);
1449
1450         n = strcspn(cgroup, "/");
1451         if (n < 3)
1452                 return -ENXIO;
1453
1454         c = strndupa(cgroup, n);
1455         c = cg_unescape(c);
1456
1457         if (!unit_name_is_valid(c, UNIT_NAME_PLAIN|UNIT_NAME_INSTANCE))
1458                 return -ENXIO;
1459
1460         s = strdup(c);
1461         if (!s)
1462                 return -ENOMEM;
1463
1464         *unit = s;
1465         return 0;
1466 }
1467
1468 static bool valid_slice_name(const char *p, size_t n) {
1469
1470         if (!p)
1471                 return false;
1472
1473         if (n < STRLEN("x.slice"))
1474                 return false;
1475
1476         if (memcmp(p + n - 6, ".slice", 6) == 0) {
1477                 char buf[n+1], *c;
1478
1479                 memcpy(buf, p, n);
1480                 buf[n] = 0;
1481
1482                 c = cg_unescape(buf);
1483
1484                 return unit_name_is_valid(c, UNIT_NAME_PLAIN);
1485         }
1486
1487         return false;
1488 }
1489
1490 static const char *skip_slices(const char *p) {
1491         assert(p);
1492
1493         /* Skips over all slice assignments */
1494
1495         for (;;) {
1496                 size_t n;
1497
1498                 p += strspn(p, "/");
1499
1500                 n = strcspn(p, "/");
1501                 if (!valid_slice_name(p, n))
1502                         return p;
1503
1504                 p += n;
1505         }
1506 }
1507
1508 int cg_path_get_unit(const char *path, char **ret) {
1509         const char *e;
1510         char *unit;
1511         int r;
1512
1513         assert(path);
1514         assert(ret);
1515
1516         e = skip_slices(path);
1517
1518         r = cg_path_decode_unit(e, &unit);
1519         if (r < 0)
1520                 return r;
1521
1522         /* We skipped over the slices, don't accept any now */
1523         if (endswith(unit, ".slice")) {
1524                 free(unit);
1525                 return -ENXIO;
1526         }
1527
1528         *ret = unit;
1529         return 0;
1530 }
1531
1532 int cg_pid_get_unit(pid_t pid, char **unit) {
1533         _cleanup_free_ char *cgroup = NULL;
1534         int r;
1535
1536         assert(unit);
1537
1538         r = cg_pid_get_path_shifted(pid, NULL, &cgroup);
1539         if (r < 0)
1540                 return r;
1541
1542         return cg_path_get_unit(cgroup, unit);
1543 }
1544
1545 /**
1546  * Skip session-*.scope, but require it to be there.
1547  */
1548 static const char *skip_session(const char *p) {
1549         size_t n;
1550
1551         if (isempty(p))
1552                 return NULL;
1553
1554         p += strspn(p, "/");
1555
1556         n = strcspn(p, "/");
1557         if (n < STRLEN("session-x.scope"))
1558                 return NULL;
1559
1560         if (memcmp(p, "session-", 8) == 0 && memcmp(p + n - 6, ".scope", 6) == 0) {
1561                 char buf[n - 8 - 6 + 1];
1562
1563                 memcpy(buf, p + 8, n - 8 - 6);
1564                 buf[n - 8 - 6] = 0;
1565
1566                 /* Note that session scopes never need unescaping,
1567                  * since they cannot conflict with the kernel's own
1568                  * names, hence we don't need to call cg_unescape()
1569                  * here. */
1570
1571                 if (!session_id_valid(buf))
1572                         return false;
1573
1574                 p += n;
1575                 p += strspn(p, "/");
1576                 return p;
1577         }
1578
1579         return NULL;
1580 }
1581
1582 /**
1583  * Skip user@*.service, but require it to be there.
1584  */
1585 static const char *skip_user_manager(const char *p) {
1586         size_t n;
1587
1588         if (isempty(p))
1589                 return NULL;
1590
1591         p += strspn(p, "/");
1592
1593         n = strcspn(p, "/");
1594         if (n < STRLEN("user@x.service"))
1595                 return NULL;
1596
1597         if (memcmp(p, "user@", 5) == 0 && memcmp(p + n - 8, ".service", 8) == 0) {
1598                 char buf[n - 5 - 8 + 1];
1599
1600                 memcpy(buf, p + 5, n - 5 - 8);
1601                 buf[n - 5 - 8] = 0;
1602
1603                 /* Note that user manager services never need unescaping,
1604                  * since they cannot conflict with the kernel's own
1605                  * names, hence we don't need to call cg_unescape()
1606                  * here. */
1607
1608                 if (parse_uid(buf, NULL) < 0)
1609                         return NULL;
1610
1611                 p += n;
1612                 p += strspn(p, "/");
1613
1614                 return p;
1615         }
1616
1617         return NULL;
1618 }
1619
1620 static const char *skip_user_prefix(const char *path) {
1621         const char *e, *t;
1622
1623         assert(path);
1624
1625         /* Skip slices, if there are any */
1626         e = skip_slices(path);
1627
1628         /* Skip the user manager, if it's in the path now... */
1629         t = skip_user_manager(e);
1630         if (t)
1631                 return t;
1632
1633         /* Alternatively skip the user session if it is in the path... */
1634         return skip_session(e);
1635 }
1636
1637 int cg_path_get_user_unit(const char *path, char **ret) {
1638         const char *t;
1639
1640         assert(path);
1641         assert(ret);
1642
1643         t = skip_user_prefix(path);
1644         if (!t)
1645                 return -ENXIO;
1646
1647         /* And from here on it looks pretty much the same as for a
1648          * system unit, hence let's use the same parser from here
1649          * on. */
1650         return cg_path_get_unit(t, ret);
1651 }
1652
1653 int cg_pid_get_user_unit(pid_t pid, char **unit) {
1654         _cleanup_free_ char *cgroup = NULL;
1655         int r;
1656
1657         assert(unit);
1658
1659         r = cg_pid_get_path_shifted(pid, NULL, &cgroup);
1660         if (r < 0)
1661                 return r;
1662
1663         return cg_path_get_user_unit(cgroup, unit);
1664 }
1665
1666 int cg_path_get_machine_name(const char *path, char **machine) {
1667         _cleanup_free_ char *u = NULL;
1668         const char *sl;
1669         int r;
1670
1671         r = cg_path_get_unit(path, &u);
1672         if (r < 0)
1673                 return r;
1674
1675         sl = strjoina("/run/systemd/machines/unit:", u);
1676         return readlink_malloc(sl, machine);
1677 }
1678
1679 int cg_pid_get_machine_name(pid_t pid, char **machine) {
1680         _cleanup_free_ char *cgroup = NULL;
1681         int r;
1682
1683         assert(machine);
1684
1685         r = cg_pid_get_path_shifted(pid, NULL, &cgroup);
1686         if (r < 0)
1687                 return r;
1688
1689         return cg_path_get_machine_name(cgroup, machine);
1690 }
1691
1692 int cg_path_get_session(const char *path, char **session) {
1693         _cleanup_free_ char *unit = NULL;
1694         char *start, *end;
1695         int r;
1696
1697         assert(path);
1698
1699         r = cg_path_get_unit(path, &unit);
1700         if (r < 0)
1701                 return r;
1702
1703         start = startswith(unit, "session-");
1704         if (!start)
1705                 return -ENXIO;
1706         end = endswith(start, ".scope");
1707         if (!end)
1708                 return -ENXIO;
1709
1710         *end = 0;
1711         if (!session_id_valid(start))
1712                 return -ENXIO;
1713
1714         if (session) {
1715                 char *rr;
1716
1717                 rr = strdup(start);
1718                 if (!rr)
1719                         return -ENOMEM;
1720
1721                 *session = rr;
1722         }
1723
1724         return 0;
1725 }
1726
1727 int cg_pid_get_session(pid_t pid, char **session) {
1728         _cleanup_free_ char *cgroup = NULL;
1729         int r;
1730
1731         r = cg_pid_get_path_shifted(pid, NULL, &cgroup);
1732         if (r < 0)
1733                 return r;
1734
1735         return cg_path_get_session(cgroup, session);
1736 }
1737
1738 int cg_path_get_owner_uid(const char *path, uid_t *uid) {
1739         _cleanup_free_ char *slice = NULL;
1740         char *start, *end;
1741         int r;
1742
1743         assert(path);
1744
1745         r = cg_path_get_slice(path, &slice);
1746         if (r < 0)
1747                 return r;
1748
1749         start = startswith(slice, "user-");
1750         if (!start)
1751                 return -ENXIO;
1752         end = endswith(start, ".slice");
1753         if (!end)
1754                 return -ENXIO;
1755
1756         *end = 0;
1757         if (parse_uid(start, uid) < 0)
1758                 return -ENXIO;
1759
1760         return 0;
1761 }
1762
1763 int cg_pid_get_owner_uid(pid_t pid, uid_t *uid) {
1764         _cleanup_free_ char *cgroup = NULL;
1765         int r;
1766
1767         r = cg_pid_get_path_shifted(pid, NULL, &cgroup);
1768         if (r < 0)
1769                 return r;
1770
1771         return cg_path_get_owner_uid(cgroup, uid);
1772 }
1773
1774 int cg_path_get_slice(const char *p, char **slice) {
1775         const char *e = NULL;
1776
1777         assert(p);
1778         assert(slice);
1779
1780         /* Finds the right-most slice unit from the beginning, but
1781          * stops before we come to the first non-slice unit. */
1782
1783         for (;;) {
1784                 size_t n;
1785
1786                 p += strspn(p, "/");
1787
1788                 n = strcspn(p, "/");
1789                 if (!valid_slice_name(p, n)) {
1790
1791                         if (!e) {
1792                                 char *s;
1793
1794                                 s = strdup(SPECIAL_ROOT_SLICE);
1795                                 if (!s)
1796                                         return -ENOMEM;
1797
1798                                 *slice = s;
1799                                 return 0;
1800                         }
1801
1802                         return cg_path_decode_unit(e, slice);
1803                 }
1804
1805                 e = p;
1806                 p += n;
1807         }
1808 }
1809
1810 int cg_pid_get_slice(pid_t pid, char **slice) {
1811         _cleanup_free_ char *cgroup = NULL;
1812         int r;
1813
1814         assert(slice);
1815
1816         r = cg_pid_get_path_shifted(pid, NULL, &cgroup);
1817         if (r < 0)
1818                 return r;
1819
1820         return cg_path_get_slice(cgroup, slice);
1821 }
1822
1823 int cg_path_get_user_slice(const char *p, char **slice) {
1824         const char *t;
1825         assert(p);
1826         assert(slice);
1827
1828         t = skip_user_prefix(p);
1829         if (!t)
1830                 return -ENXIO;
1831
1832         /* And now it looks pretty much the same as for a system
1833          * slice, so let's just use the same parser from here on. */
1834         return cg_path_get_slice(t, slice);
1835 }
1836
1837 int cg_pid_get_user_slice(pid_t pid, char **slice) {
1838         _cleanup_free_ char *cgroup = NULL;
1839         int r;
1840
1841         assert(slice);
1842
1843         r = cg_pid_get_path_shifted(pid, NULL, &cgroup);
1844         if (r < 0)
1845                 return r;
1846
1847         return cg_path_get_user_slice(cgroup, slice);
1848 }
1849
1850 char *cg_escape(const char *p) {
1851         bool need_prefix = false;
1852
1853         /* This implements very minimal escaping for names to be used
1854          * as file names in the cgroup tree: any name which might
1855          * conflict with a kernel name or is prefixed with '_' is
1856          * prefixed with a '_'. That way, when reading cgroup names it
1857          * is sufficient to remove a single prefixing underscore if
1858          * there is one. */
1859
1860         /* The return value of this function (unlike cg_unescape())
1861          * needs free()! */
1862
1863         if (IN_SET(p[0], 0, '_', '.') ||
1864             streq(p, "notify_on_release") ||
1865             streq(p, "release_agent") ||
1866             streq(p, "tasks") ||
1867             startswith(p, "cgroup."))
1868                 need_prefix = true;
1869         else {
1870                 const char *dot;
1871
1872                 dot = strrchr(p, '.');
1873                 if (dot) {
1874                         CGroupController c;
1875                         size_t l = dot - p;
1876
1877                         for (c = 0; c < _CGROUP_CONTROLLER_MAX; c++) {
1878                                 const char *n;
1879
1880                                 n = cgroup_controller_to_string(c);
1881
1882                                 if (l != strlen(n))
1883                                         continue;
1884
1885                                 if (memcmp(p, n, l) != 0)
1886                                         continue;
1887
1888                                 need_prefix = true;
1889                                 break;
1890                         }
1891                 }
1892         }
1893
1894         if (need_prefix)
1895                 return strappend("_", p);
1896
1897         return strdup(p);
1898 }
1899
1900 char *cg_unescape(const char *p) {
1901         assert(p);
1902
1903         /* The return value of this function (unlike cg_escape())
1904          * doesn't need free()! */
1905
1906         if (p[0] == '_')
1907                 return (char*) p+1;
1908
1909         return (char*) p;
1910 }
1911
1912 #define CONTROLLER_VALID                        \
1913         DIGITS LETTERS                          \
1914         "_"
1915
1916 bool cg_controller_is_valid(const char *p) {
1917         const char *t, *s;
1918
1919         if (!p)
1920                 return false;
1921
1922         if (streq(p, SYSTEMD_CGROUP_CONTROLLER))
1923                 return true;
1924
1925         s = startswith(p, "name=");
1926         if (s)
1927                 p = s;
1928
1929         if (IN_SET(*p, 0, '_'))
1930                 return false;
1931
1932         for (t = p; *t; t++)
1933                 if (!strchr(CONTROLLER_VALID, *t))
1934                         return false;
1935
1936         if (t - p > FILENAME_MAX)
1937                 return false;
1938
1939         return true;
1940 }
1941
1942 int cg_slice_to_path(const char *unit, char **ret) {
1943         _cleanup_free_ char *p = NULL, *s = NULL, *e = NULL;
1944         const char *dash;
1945         int r;
1946
1947         assert(unit);
1948         assert(ret);
1949
1950         if (streq(unit, SPECIAL_ROOT_SLICE)) {
1951                 char *x;
1952
1953                 x = strdup("");
1954                 if (!x)
1955                         return -ENOMEM;
1956                 *ret = x;
1957                 return 0;
1958         }
1959
1960         if (!unit_name_is_valid(unit, UNIT_NAME_PLAIN))
1961                 return -EINVAL;
1962
1963         if (!endswith(unit, ".slice"))
1964                 return -EINVAL;
1965
1966         r = unit_name_to_prefix(unit, &p);
1967         if (r < 0)
1968                 return r;
1969
1970         dash = strchr(p, '-');
1971
1972         /* Don't allow initial dashes */
1973         if (dash == p)
1974                 return -EINVAL;
1975
1976         while (dash) {
1977                 _cleanup_free_ char *escaped = NULL;
1978                 char n[dash - p + sizeof(".slice")];
1979
1980                 /* Don't allow trailing or double dashes */
1981                 if (IN_SET(dash[1], 0, '-'))
1982                         return -EINVAL;
1983
1984                 strcpy(stpncpy(n, p, dash - p), ".slice");
1985                 if (!unit_name_is_valid(n, UNIT_NAME_PLAIN))
1986                         return -EINVAL;
1987
1988                 escaped = cg_escape(n);
1989                 if (!escaped)
1990                         return -ENOMEM;
1991
1992                 if (!strextend(&s, escaped, "/", NULL))
1993                         return -ENOMEM;
1994
1995                 dash = strchr(dash+1, '-');
1996         }
1997
1998         e = cg_escape(unit);
1999         if (!e)
2000                 return -ENOMEM;
2001
2002         if (!strextend(&s, e, NULL))
2003                 return -ENOMEM;
2004
2005         *ret = s;
2006         s = NULL;
2007
2008         return 0;
2009 }
2010
2011 int cg_set_attribute(const char *controller, const char *path, const char *attribute, const char *value) {
2012         _cleanup_free_ char *p = NULL;
2013         int r;
2014
2015         r = cg_get_path(controller, path, attribute, &p);
2016         if (r < 0)
2017                 return r;
2018
2019         return write_string_file(p, value, 0);
2020 }
2021
2022 int cg_get_attribute(const char *controller, const char *path, const char *attribute, char **ret) {
2023         _cleanup_free_ char *p = NULL;
2024         int r;
2025
2026         r = cg_get_path(controller, path, attribute, &p);
2027         if (r < 0)
2028                 return r;
2029
2030         return read_one_line_file(p, ret);
2031 }
2032
2033 int cg_get_keyed_attribute(
2034                 const char *controller,
2035                 const char *path,
2036                 const char *attribute,
2037                 char **keys,
2038                 char **ret_values) {
2039
2040         _cleanup_free_ char *filename = NULL, *contents = NULL;
2041         const char *p;
2042         size_t n, i, n_done = 0;
2043         char **v;
2044         int r;
2045
2046         /* Reads one or more fields of a cgroupsv2 keyed attribute file. The 'keys' parameter should be an strv with
2047          * all keys to retrieve. The 'ret_values' parameter should be passed as string size with the same number of
2048          * entries as 'keys'. On success each entry will be set to the value of the matching key.
2049          *
2050          * If the attribute file doesn't exist at all returns ENOENT, if any key is not found returns ENXIO. */
2051
2052         r = cg_get_path(controller, path, attribute, &filename);
2053         if (r < 0)
2054                 return r;
2055
2056         r = read_full_file(filename, &contents, NULL);
2057         if (r < 0)
2058                 return r;
2059
2060         n = strv_length(keys);
2061         if (n == 0) /* No keys to retrieve? That's easy, we are done then */
2062                 return 0;
2063
2064         /* Let's build this up in a temporary array for now in order not to clobber the return parameter on failure */
2065         v = newa0(char*, n);
2066
2067         for (p = contents; *p;) {
2068                 const char *w = NULL;
2069
2070                 for (i = 0; i < n; i++)
2071                         if (!v[i]) {
2072                                 w = first_word(p, keys[i]);
2073                                 if (w)
2074                                         break;
2075                         }
2076
2077                 if (w) {
2078                         size_t l;
2079
2080                         l = strcspn(w, NEWLINE);
2081                         v[i] = strndup(w, l);
2082                         if (!v[i]) {
2083                                 r = -ENOMEM;
2084                                 goto fail;
2085                         }
2086
2087                         n_done++;
2088                         if (n_done >= n)
2089                                 goto done;
2090
2091                         p = w + l;
2092                 } else
2093                         p += strcspn(p, NEWLINE);
2094
2095                 p += strspn(p, NEWLINE);
2096         }
2097
2098         r = -ENXIO;
2099
2100 fail:
2101         for (i = 0; i < n; i++)
2102                 free(v[i]);
2103
2104         return r;
2105
2106 done:
2107         memcpy(ret_values, v, sizeof(char*) * n);
2108         return 0;
2109
2110 }
2111
2112 int cg_create_everywhere(CGroupMask supported, CGroupMask mask, const char *path) {
2113         CGroupController c;
2114         int r;
2115
2116         /* This one will create a cgroup in our private tree, but also
2117          * duplicate it in the trees specified in mask, and remove it
2118          * in all others */
2119
2120         /* First create the cgroup in our own hierarchy. */
2121         r = cg_create(SYSTEMD_CGROUP_CONTROLLER, path);
2122         if (r < 0)
2123                 return r;
2124
2125         /* If we are in the unified hierarchy, we are done now */
2126         r = cg_all_unified();
2127         if (r < 0)
2128                 return r;
2129         if (r > 0)
2130                 return 0;
2131
2132         /* Otherwise, do the same in the other hierarchies */
2133         for (c = 0; c < _CGROUP_CONTROLLER_MAX; c++) {
2134                 CGroupMask bit = CGROUP_CONTROLLER_TO_MASK(c);
2135                 const char *n;
2136
2137                 n = cgroup_controller_to_string(c);
2138
2139                 if (mask & bit)
2140                         (void) cg_create(n, path);
2141                 else if (supported & bit)
2142                         (void) cg_trim(n, path, true);
2143         }
2144
2145         return 0;
2146 }
2147
2148 int cg_attach_everywhere(CGroupMask supported, const char *path, pid_t pid, cg_migrate_callback_t path_callback, void *userdata) {
2149         CGroupController c;
2150         int r;
2151
2152         r = cg_attach(SYSTEMD_CGROUP_CONTROLLER, path, pid);
2153         if (r < 0)
2154                 return r;
2155
2156         r = cg_all_unified();
2157         if (r < 0)
2158                 return r;
2159         if (r > 0)
2160                 return 0;
2161
2162         for (c = 0; c < _CGROUP_CONTROLLER_MAX; c++) {
2163                 CGroupMask bit = CGROUP_CONTROLLER_TO_MASK(c);
2164                 const char *p = NULL;
2165
2166                 if (!(supported & bit))
2167                         continue;
2168
2169                 if (path_callback)
2170                         p = path_callback(bit, userdata);
2171
2172                 if (!p)
2173                         p = path;
2174
2175                 (void) cg_attach_fallback(cgroup_controller_to_string(c), p, pid);
2176         }
2177
2178         return 0;
2179 }
2180
2181 int cg_attach_many_everywhere(CGroupMask supported, const char *path, Set* pids, cg_migrate_callback_t path_callback, void *userdata) {
2182         Iterator i;
2183         void *pidp;
2184         int r = 0;
2185
2186         SET_FOREACH(pidp, pids, i) {
2187                 pid_t pid = PTR_TO_PID(pidp);
2188                 int q;
2189
2190                 q = cg_attach_everywhere(supported, path, pid, path_callback, userdata);
2191                 if (q < 0 && r >= 0)
2192                         r = q;
2193         }
2194
2195         return r;
2196 }
2197
2198 int cg_migrate_everywhere(CGroupMask supported, const char *from, const char *to, cg_migrate_callback_t to_callback, void *userdata) {
2199         CGroupController c;
2200         int r = 0, q;
2201
2202         if (!path_equal(from, to))  {
2203                 r = cg_migrate_recursive(SYSTEMD_CGROUP_CONTROLLER, from, SYSTEMD_CGROUP_CONTROLLER, to, CGROUP_REMOVE);
2204                 if (r < 0)
2205                         return r;
2206         }
2207
2208         q = cg_all_unified();
2209         if (q < 0)
2210                 return q;
2211         if (q > 0)
2212                 return r;
2213
2214         for (c = 0; c < _CGROUP_CONTROLLER_MAX; c++) {
2215                 CGroupMask bit = CGROUP_CONTROLLER_TO_MASK(c);
2216                 const char *p = NULL;
2217
2218                 if (!(supported & bit))
2219                         continue;
2220
2221                 if (to_callback)
2222                         p = to_callback(bit, userdata);
2223
2224                 if (!p)
2225                         p = to;
2226
2227                 (void) cg_migrate_recursive_fallback(SYSTEMD_CGROUP_CONTROLLER, to, cgroup_controller_to_string(c), p, 0);
2228         }
2229
2230         return 0;
2231 }
2232
2233 int cg_trim_everywhere(CGroupMask supported, const char *path, bool delete_root) {
2234         CGroupController c;
2235         int r, q;
2236
2237         r = cg_trim(SYSTEMD_CGROUP_CONTROLLER, path, delete_root);
2238         if (r < 0)
2239                 return r;
2240
2241         q = cg_all_unified();
2242         if (q < 0)
2243                 return q;
2244         if (q > 0)
2245                 return r;
2246
2247         for (c = 0; c < _CGROUP_CONTROLLER_MAX; c++) {
2248                 CGroupMask bit = CGROUP_CONTROLLER_TO_MASK(c);
2249
2250                 if (!(supported & bit))
2251                         continue;
2252
2253                 (void) cg_trim(cgroup_controller_to_string(c), path, delete_root);
2254         }
2255
2256         return 0;
2257 }
2258
2259 int cg_mask_to_string(CGroupMask mask, char **ret) {
2260         _cleanup_free_ char *s = NULL;
2261         size_t n = 0, allocated = 0;
2262         bool space = false;
2263         CGroupController c;
2264
2265         assert(ret);
2266
2267         if (mask == 0) {
2268                 *ret = NULL;
2269                 return 0;
2270         }
2271
2272         for (c = 0; c < _CGROUP_CONTROLLER_MAX; c++) {
2273                 const char *k;
2274                 size_t l;
2275
2276                 if (!(mask & CGROUP_CONTROLLER_TO_MASK(c)))
2277                         continue;
2278
2279                 k = cgroup_controller_to_string(c);
2280                 l = strlen(k);
2281
2282                 if (!GREEDY_REALLOC(s, allocated, n + space + l + 1))
2283                         return -ENOMEM;
2284
2285                 if (space)
2286                         s[n] = ' ';
2287                 memcpy(s + n + space, k, l);
2288                 n += space + l;
2289
2290                 space = true;
2291         }
2292
2293         assert(s);
2294
2295         s[n] = 0;
2296         *ret = s;
2297         s = NULL;
2298
2299         return 0;
2300 }
2301
2302 int cg_mask_from_string(const char *value, CGroupMask *mask) {
2303         assert(mask);
2304         assert(value);
2305
2306         for (;;) {
2307                 _cleanup_free_ char *n = NULL;
2308                 CGroupController v;
2309                 int r;
2310
2311                 r = extract_first_word(&value, &n, NULL, 0);
2312                 if (r < 0)
2313                         return r;
2314                 if (r == 0)
2315                         break;
2316
2317                 v = cgroup_controller_from_string(n);
2318                 if (v < 0)
2319                         continue;
2320
2321                 *mask |= CGROUP_CONTROLLER_TO_MASK(v);
2322         }
2323         return 0;
2324 }
2325
2326 int cg_mask_supported(CGroupMask *ret) {
2327         CGroupMask mask = 0;
2328         int r;
2329
2330         /* Determines the mask of supported cgroup controllers. Only
2331          * includes controllers we can make sense of and that are
2332          * actually accessible. */
2333
2334         r = cg_all_unified();
2335         if (r < 0)
2336                 return r;
2337         if (r > 0) {
2338                 _cleanup_free_ char *root = NULL, *controllers = NULL, *path = NULL;
2339
2340                 /* In the unified hierarchy we can read the supported
2341                  * and accessible controllers from a the top-level
2342                  * cgroup attribute */
2343
2344                 r = cg_get_root_path(&root);
2345                 if (r < 0)
2346                         return r;
2347
2348                 r = cg_get_path(SYSTEMD_CGROUP_CONTROLLER, root, "cgroup.controllers", &path);
2349                 if (r < 0)
2350                         return r;
2351
2352                 r = read_one_line_file(path, &controllers);
2353                 if (r < 0)
2354                         return r;
2355
2356                 r = cg_mask_from_string(controllers, &mask);
2357                 if (r < 0)
2358                         return r;
2359
2360                 /* Currently, we support the cpu, memory, io and pids
2361                  * controller in the unified hierarchy, mask
2362                  * everything else off. */
2363                 mask &= CGROUP_MASK_CPU | CGROUP_MASK_MEMORY | CGROUP_MASK_IO | CGROUP_MASK_PIDS;
2364
2365         } else {
2366                 CGroupController c;
2367
2368                 /* In the legacy hierarchy, we check whether which
2369                  * hierarchies are mounted. */
2370
2371                 for (c = 0; c < _CGROUP_CONTROLLER_MAX; c++) {
2372                         const char *n;
2373
2374                         n = cgroup_controller_to_string(c);
2375                         if (controller_is_accessible(n) >= 0)
2376                                 mask |= CGROUP_CONTROLLER_TO_MASK(c);
2377                 }
2378         }
2379
2380         *ret = mask;
2381         return 0;
2382 }
2383
2384 int cg_kernel_controllers(Set **ret) {
2385         _cleanup_set_free_free_ Set *controllers = NULL;
2386         _cleanup_fclose_ FILE *f = NULL;
2387         int r;
2388
2389         assert(ret);
2390
2391         /* Determines the full list of kernel-known controllers. Might
2392          * include controllers we don't actually support, arbitrary
2393          * named hierarchies and controllers that aren't currently
2394          * accessible (because not mounted). */
2395
2396         controllers = set_new(&string_hash_ops);
2397         if (!controllers)
2398                 return -ENOMEM;
2399
2400         f = fopen("/proc/cgroups", "re");
2401         if (!f) {
2402                 if (errno == ENOENT) {
2403                         *ret = NULL;
2404                         return 0;
2405                 }
2406
2407                 return -errno;
2408         }
2409
2410         (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
2411
2412         /* Ignore the header line */
2413         (void) read_line(f, (size_t) -1, NULL);
2414
2415         for (;;) {
2416                 char *controller;
2417                 int enabled = 0;
2418
2419                 errno = 0;
2420                 if (fscanf(f, "%ms %*i %*i %i", &controller, &enabled) != 2) {
2421
2422                         if (feof(f))
2423                                 break;
2424
2425                         if (ferror(f) && errno > 0)
2426                                 return -errno;
2427
2428                         return -EBADMSG;
2429                 }
2430
2431                 if (!enabled) {
2432                         free(controller);
2433                         continue;
2434                 }
2435
2436                 if (!cg_controller_is_valid(controller)) {
2437                         free(controller);
2438                         return -EBADMSG;
2439                 }
2440
2441                 r = set_consume(controllers, controller);
2442                 if (r < 0)
2443                         return r;
2444         }
2445
2446         *ret = controllers;
2447         controllers = NULL;
2448
2449         return 0;
2450 }
2451
2452 static thread_local CGroupUnified unified_cache = CGROUP_UNIFIED_UNKNOWN;
2453
2454 /* The hybrid mode was initially implemented in v232 and simply mounted cgroup v2 on /sys/fs/cgroup/systemd.  This
2455  * unfortunately broke other tools (such as docker) which expected the v1 "name=systemd" hierarchy on
2456  * /sys/fs/cgroup/systemd.  From v233 and on, the hybrid mode mountnbs v2 on /sys/fs/cgroup/unified and maintains
2457  * "name=systemd" hierarchy on /sys/fs/cgroup/systemd for compatibility with other tools.
2458  *
2459  * To keep live upgrade working, we detect and support v232 layout.  When v232 layout is detected, to keep cgroup v2
2460  * process management but disable the compat dual layout, we return %true on
2461  * cg_unified_controller(SYSTEMD_CGROUP_CONTROLLER) and %false on cg_hybrid_unified().
2462  */
2463 static thread_local bool unified_systemd_v232;
2464
2465 static int cg_unified_update(void) {
2466
2467         struct statfs fs;
2468
2469         /* Checks if we support the unified hierarchy. Returns an
2470          * error when the cgroup hierarchies aren't mounted yet or we
2471          * have any other trouble determining if the unified hierarchy
2472          * is supported. */
2473
2474         if (unified_cache >= CGROUP_UNIFIED_NONE)
2475                 return 0;
2476
2477         if (statfs("/sys/fs/cgroup/", &fs) < 0)
2478                 return log_debug_errno(errno, "statfs(\"/sys/fs/cgroup/\" failed: %m");
2479
2480         if (F_TYPE_EQUAL(fs.f_type, CGROUP2_SUPER_MAGIC)) {
2481                 log_debug("Found cgroup2 on /sys/fs/cgroup/, full unified hierarchy");
2482                 unified_cache = CGROUP_UNIFIED_ALL;
2483         } else if (F_TYPE_EQUAL(fs.f_type, TMPFS_MAGIC)) {
2484                 if (statfs("/sys/fs/cgroup/unified/", &fs) == 0 &&
2485                     F_TYPE_EQUAL(fs.f_type, CGROUP2_SUPER_MAGIC)) {
2486                         log_debug("Found cgroup2 on /sys/fs/cgroup/unified, unified hierarchy for systemd controller");
2487                         unified_cache = CGROUP_UNIFIED_SYSTEMD;
2488                         unified_systemd_v232 = false;
2489                 } else {
2490                         if (statfs("/sys/fs/cgroup/systemd/", &fs) < 0)
2491                                 return log_debug_errno(errno, "statfs(\"/sys/fs/cgroup/systemd\" failed: %m");
2492
2493                         if (F_TYPE_EQUAL(fs.f_type, CGROUP2_SUPER_MAGIC)) {
2494                                 log_debug("Found cgroup2 on /sys/fs/cgroup/systemd, unified hierarchy for systemd controller (v232 variant)");
2495                                 unified_cache = CGROUP_UNIFIED_SYSTEMD;
2496                                 unified_systemd_v232 = true;
2497                         } else if (F_TYPE_EQUAL(fs.f_type, CGROUP_SUPER_MAGIC)) {
2498                                 log_debug("Found cgroup on /sys/fs/cgroup/systemd, legacy hierarchy");
2499                                 unified_cache = CGROUP_UNIFIED_NONE;
2500                         } else {
2501                                 log_debug("Unexpected filesystem type %llx mounted on /sys/fs/cgroup/systemd, assuming legacy hierarchy",
2502                                           (unsigned long long) fs.f_type);
2503                                 unified_cache = CGROUP_UNIFIED_NONE;
2504                         }
2505                 }
2506         } else {
2507                 log_debug("Unknown filesystem type %llx mounted on /sys/fs/cgroup.",
2508                           (unsigned long long) fs.f_type);
2509                 return -ENOMEDIUM;
2510         }
2511
2512         return 0;
2513 }
2514
2515 int cg_unified_controller(const char *controller) {
2516         int r;
2517
2518         r = cg_unified_update();
2519         if (r < 0)
2520                 return r;
2521
2522         if (unified_cache == CGROUP_UNIFIED_NONE)
2523                 return false;
2524
2525         if (unified_cache >= CGROUP_UNIFIED_ALL)
2526                 return true;
2527
2528         return streq_ptr(controller, SYSTEMD_CGROUP_CONTROLLER);
2529 }
2530
2531 int cg_all_unified(void) {
2532         int r;
2533
2534         r = cg_unified_update();
2535         if (r < 0)
2536                 return r;
2537
2538         return unified_cache >= CGROUP_UNIFIED_ALL;
2539 }
2540
2541 int cg_hybrid_unified(void) {
2542         int r;
2543
2544         r = cg_unified_update();
2545         if (r < 0)
2546                 return r;
2547
2548         return unified_cache == CGROUP_UNIFIED_SYSTEMD && !unified_systemd_v232;
2549 }
2550
2551 int cg_unified_flush(void) {
2552         unified_cache = CGROUP_UNIFIED_UNKNOWN;
2553
2554         return cg_unified_update();
2555 }
2556
2557 int cg_enable_everywhere(CGroupMask supported, CGroupMask mask, const char *p) {
2558         _cleanup_fclose_ FILE *f = NULL;
2559         _cleanup_free_ char *fs = NULL;
2560         CGroupController c;
2561         int r;
2562
2563         assert(p);
2564
2565         if (supported == 0)
2566                 return 0;
2567
2568         r = cg_all_unified();
2569         if (r < 0)
2570                 return r;
2571         if (r == 0) /* on the legacy hiearchy there's no joining of controllers defined */
2572                 return 0;
2573
2574         r = cg_get_path(SYSTEMD_CGROUP_CONTROLLER, p, "cgroup.subtree_control", &fs);
2575         if (r < 0)
2576                 return r;
2577
2578         for (c = 0; c < _CGROUP_CONTROLLER_MAX; c++) {
2579                 CGroupMask bit = CGROUP_CONTROLLER_TO_MASK(c);
2580                 const char *n;
2581
2582                 if (!(supported & bit))
2583                         continue;
2584
2585                 n = cgroup_controller_to_string(c);
2586                 {
2587                         char s[1 + strlen(n) + 1];
2588
2589                         s[0] = mask & bit ? '+' : '-';
2590                         strcpy(s + 1, n);
2591
2592                         if (!f) {
2593                                 f = fopen(fs, "we");
2594                                 if (!f) {
2595                                         log_debug_errno(errno, "Failed to open cgroup.subtree_control file of %s: %m", p);
2596                                         break;
2597                                 }
2598                         }
2599
2600                         r = write_string_stream(f, s, 0);
2601                         if (r < 0)
2602                                 log_debug_errno(r, "Failed to enable controller %s for %s (%s): %m", n, p, fs);
2603                 }
2604         }
2605
2606         return 0;
2607 }
2608
2609 bool cg_is_unified_wanted(void) {
2610         static thread_local int wanted = -1;
2611         int r;
2612         bool b;
2613         const bool is_default = DEFAULT_HIERARCHY == CGROUP_UNIFIED_ALL;
2614
2615         /* If we have a cached value, return that. */
2616         if (wanted >= 0)
2617                 return wanted;
2618
2619         /* If the hierarchy is already mounted, then follow whatever
2620          * was chosen for it. */
2621         if (cg_unified_flush() >= 0)
2622                 return (wanted = unified_cache >= CGROUP_UNIFIED_ALL);
2623
2624         /* Otherwise, let's see what the kernel command line has to say.
2625          * Since checking is expensive, cache a non-error result. */
2626         r = proc_cmdline_get_bool("systemd.unified_cgroup_hierarchy", &b);
2627
2628         return (wanted = r > 0 ? b : is_default);
2629 }
2630
2631 bool cg_is_legacy_wanted(void) {
2632         static thread_local int wanted = -1;
2633
2634         /* If we have a cached value, return that. */
2635         if (wanted >= 0)
2636                 return wanted;
2637
2638         /* Check if we have cgroups2 already mounted. */
2639         if (cg_unified_flush() >= 0 &&
2640             unified_cache == CGROUP_UNIFIED_ALL)
2641                 return (wanted = false);
2642
2643         /* Otherwise, assume that at least partial legacy is wanted,
2644          * since cgroups2 should already be mounted at this point. */
2645         return (wanted = true);
2646 }
2647
2648 bool cg_is_hybrid_wanted(void) {
2649         static thread_local int wanted = -1;
2650         int r;
2651         bool b;
2652         const bool is_default = DEFAULT_HIERARCHY >= CGROUP_UNIFIED_SYSTEMD;
2653         /* We default to true if the default is "hybrid", obviously,
2654          * but also when the default is "unified", because if we get
2655          * called, it means that unified hierarchy was not mounted. */
2656
2657         /* If we have a cached value, return that. */
2658         if (wanted >= 0)
2659                 return wanted;
2660
2661         /* If the hierarchy is already mounted, then follow whatever
2662          * was chosen for it. */
2663         if (cg_unified_flush() >= 0 &&
2664             unified_cache == CGROUP_UNIFIED_ALL)
2665                 return (wanted = false);
2666
2667         /* Otherwise, let's see what the kernel command line has to say.
2668          * Since checking is expensive, cache a non-error result. */
2669         r = proc_cmdline_get_bool("systemd.legacy_systemd_cgroup_controller", &b);
2670
2671         /* The meaning of the kernel option is reversed wrt. to the return value
2672          * of this function, hence the negation. */
2673         return (wanted = r > 0 ? !b : is_default);
2674 }
2675
2676 int cg_weight_parse(const char *s, uint64_t *ret) {
2677         uint64_t u;
2678         int r;
2679
2680         if (isempty(s)) {
2681                 *ret = CGROUP_WEIGHT_INVALID;
2682                 return 0;
2683         }
2684
2685         r = safe_atou64(s, &u);
2686         if (r < 0)
2687                 return r;
2688
2689         if (u < CGROUP_WEIGHT_MIN || u > CGROUP_WEIGHT_MAX)
2690                 return -ERANGE;
2691
2692         *ret = u;
2693         return 0;
2694 }
2695
2696 const uint64_t cgroup_io_limit_defaults[_CGROUP_IO_LIMIT_TYPE_MAX] = {
2697         [CGROUP_IO_RBPS_MAX]    = CGROUP_LIMIT_MAX,
2698         [CGROUP_IO_WBPS_MAX]    = CGROUP_LIMIT_MAX,
2699         [CGROUP_IO_RIOPS_MAX]   = CGROUP_LIMIT_MAX,
2700         [CGROUP_IO_WIOPS_MAX]   = CGROUP_LIMIT_MAX,
2701 };
2702
2703 static const char* const cgroup_io_limit_type_table[_CGROUP_IO_LIMIT_TYPE_MAX] = {
2704         [CGROUP_IO_RBPS_MAX]    = "IOReadBandwidthMax",
2705         [CGROUP_IO_WBPS_MAX]    = "IOWriteBandwidthMax",
2706         [CGROUP_IO_RIOPS_MAX]   = "IOReadIOPSMax",
2707         [CGROUP_IO_WIOPS_MAX]   = "IOWriteIOPSMax",
2708 };
2709
2710 DEFINE_STRING_TABLE_LOOKUP(cgroup_io_limit_type, CGroupIOLimitType);
2711
2712 int cg_cpu_shares_parse(const char *s, uint64_t *ret) {
2713         uint64_t u;
2714         int r;
2715
2716         if (isempty(s)) {
2717                 *ret = CGROUP_CPU_SHARES_INVALID;
2718                 return 0;
2719         }
2720
2721         r = safe_atou64(s, &u);
2722         if (r < 0)
2723                 return r;
2724
2725         if (u < CGROUP_CPU_SHARES_MIN || u > CGROUP_CPU_SHARES_MAX)
2726                 return -ERANGE;
2727
2728         *ret = u;
2729         return 0;
2730 }
2731
2732 int cg_blkio_weight_parse(const char *s, uint64_t *ret) {
2733         uint64_t u;
2734         int r;
2735
2736         if (isempty(s)) {
2737                 *ret = CGROUP_BLKIO_WEIGHT_INVALID;
2738                 return 0;
2739         }
2740
2741         r = safe_atou64(s, &u);
2742         if (r < 0)
2743                 return r;
2744
2745         if (u < CGROUP_BLKIO_WEIGHT_MIN || u > CGROUP_BLKIO_WEIGHT_MAX)
2746                 return -ERANGE;
2747
2748         *ret = u;
2749         return 0;
2750 }
2751
2752 bool is_cgroup_fs(const struct statfs *s) {
2753         return is_fs_type(s, CGROUP_SUPER_MAGIC) ||
2754                is_fs_type(s, CGROUP2_SUPER_MAGIC);
2755 }
2756
2757 bool fd_is_cgroup_fs(int fd) {
2758         struct statfs s;
2759
2760         if (fstatfs(fd, &s) < 0)
2761                 return -errno;
2762
2763         return is_cgroup_fs(&s);
2764 }
2765
2766 static const char *cgroup_controller_table[_CGROUP_CONTROLLER_MAX] = {
2767         [CGROUP_CONTROLLER_CPU] = "cpu",
2768         [CGROUP_CONTROLLER_CPUACCT] = "cpuacct",
2769         [CGROUP_CONTROLLER_IO] = "io",
2770         [CGROUP_CONTROLLER_BLKIO] = "blkio",
2771         [CGROUP_CONTROLLER_MEMORY] = "memory",
2772         [CGROUP_CONTROLLER_DEVICES] = "devices",
2773         [CGROUP_CONTROLLER_PIDS] = "pids",
2774 };
2775
2776 DEFINE_STRING_TABLE_LOOKUP(cgroup_controller, CGroupController);