1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
4 This file is part of systemd.
6 Copyright 2010 Lennart Poettering
8 systemd is free software; you can redistribute it and/or modify it
9 under the terms of the GNU Lesser General Public License as published by
10 the Free Software Foundation; either version 2.1 of the License, or
11 (at your option) any later version.
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 Lesser General Public License for more details.
18 You should have received a copy of the GNU Lesser General Public License
19 along with systemd; If not, see <http://www.gnu.org/licenses/>.
29 #include <sys/types.h>
32 #include "cgroup-util.h"
38 int cg_enumerate_processes(const char *controller, const char *path, FILE **_f) {
47 if ((r = cg_get_path(controller, path, "cgroup.procs", &fs)) < 0)
60 int cg_enumerate_tasks(const char *controller, const char *path, FILE **_f) {
69 if ((r = cg_get_path(controller, path, "tasks", &fs)) < 0)
82 int cg_read_pid(FILE *f, pid_t *_pid) {
85 /* Note that the cgroup.procs might contain duplicates! See
86 * cgroups.txt for details. */
89 if (fscanf(f, "%lu", &ul) != 1) {
94 return errno ? -errno : -EIO;
104 int cg_enumerate_subgroups(const char *controller, const char *path, DIR **_d) {
113 /* This is not recursive! */
115 if ((r = cg_get_path(controller, path, NULL, &fs)) < 0)
128 int cg_read_subgroup(DIR *d, char **fn) {
134 while ((de = readdir(d))) {
137 if (de->d_type != DT_DIR)
140 if (streq(de->d_name, ".") ||
141 streq(de->d_name, ".."))
144 if (!(b = strdup(de->d_name)))
157 int cg_rmdir(const char *controller, const char *path, bool honour_sticky) {
161 r = cg_get_path(controller, path, NULL, &p);
168 /* If the sticky bit is set don't remove the directory */
170 tasks = strappend(p, "/tasks");
176 r = file_is_priv_sticky(tasks);
188 return (r < 0 && errno != ENOENT) ? -errno : 0;
191 int cg_kill(const char *controller, const char *path, int sig, bool sigcont, bool ignore_self, Set *s) {
196 Set *allocated_set = NULL;
202 /* This goes through the tasks list and kills them all. This
203 * is repeated until no further processes are added to the
204 * tasks list, to properly handle forking processes */
207 if (!(s = allocated_set = set_new(trivial_hash_func, trivial_compare_func)))
216 if ((r = cg_enumerate_processes(controller, path, &f)) < 0) {
217 if (ret >= 0 && r != -ENOENT)
223 while ((r = cg_read_pid(f, &pid)) > 0) {
225 if (pid == my_pid && ignore_self)
228 if (set_get(s, LONG_TO_PTR(pid)) == LONG_TO_PTR(pid))
231 /* If we haven't killed this process yet, kill
233 if (kill(pid, sig) < 0) {
234 if (ret >= 0 && errno != ESRCH)
236 } else if (ret == 0) {
246 if ((r = set_put(s, LONG_TO_PTR(pid))) < 0) {
264 /* To avoid racing against processes which fork
265 * quicker than we can kill them we repeat this until
266 * no new pids need to be killed. */
272 set_free(allocated_set);
280 int cg_kill_recursive(const char *controller, const char *path, int sig, bool sigcont, bool ignore_self, bool rem, Set *s) {
284 Set *allocated_set = NULL;
291 if (!(s = allocated_set = set_new(trivial_hash_func, trivial_compare_func)))
294 ret = cg_kill(controller, path, sig, sigcont, ignore_self, s);
296 if ((r = cg_enumerate_subgroups(controller, path, &d)) < 0) {
297 if (ret >= 0 && r != -ENOENT)
303 while ((r = cg_read_subgroup(d, &fn)) > 0) {
306 r = asprintf(&p, "%s/%s", path, fn);
316 r = cg_kill_recursive(controller, p, sig, sigcont, ignore_self, rem, s);
319 if (r != 0 && ret >= 0)
323 if (r < 0 && ret >= 0)
327 if ((r = cg_rmdir(controller, path, true)) < 0) {
339 set_free(allocated_set);
344 int cg_kill_recursive_and_wait(const char *controller, const char *path, bool rem) {
350 /* This safely kills all processes; first it sends a SIGTERM,
351 * then checks 8 times after 200ms whether the group is now
352 * empty, then kills everything that is left with SIGKILL and
353 * finally checks 5 times after 200ms each whether the group
354 * is finally empty. */
356 for (i = 0; i < 15; i++) {
366 if ((r = cg_kill_recursive(controller, path, sig, true, true, rem, NULL)) <= 0)
369 usleep(200 * USEC_PER_MSEC);
375 int cg_migrate(const char *controller, const char *from, const char *to, bool ignore_self) {
386 if (!(s = set_new(trivial_hash_func, trivial_compare_func)))
395 if ((r = cg_enumerate_tasks(controller, from, &f)) < 0) {
396 if (ret >= 0 && r != -ENOENT)
402 while ((r = cg_read_pid(f, &pid)) > 0) {
404 /* This might do weird stuff if we aren't a
405 * single-threaded program. However, we
406 * luckily know we are not */
407 if (pid == my_pid && ignore_self)
410 if (set_get(s, LONG_TO_PTR(pid)) == LONG_TO_PTR(pid))
413 if ((r = cg_attach(controller, to, pid)) < 0) {
414 if (ret >= 0 && r != -ESRCH)
421 if ((r = set_put(s, LONG_TO_PTR(pid))) < 0) {
450 int cg_migrate_recursive(const char *controller, const char *from, const char *to, bool ignore_self, bool rem) {
459 ret = cg_migrate(controller, from, to, ignore_self);
461 if ((r = cg_enumerate_subgroups(controller, from, &d)) < 0) {
462 if (ret >= 0 && r != -ENOENT)
467 while ((r = cg_read_subgroup(d, &fn)) > 0) {
470 r = asprintf(&p, "%s/%s", from, fn);
480 r = cg_migrate_recursive(controller, p, to, ignore_self, rem);
483 if (r != 0 && ret >= 0)
487 if (r < 0 && ret >= 0)
491 if ((r = cg_rmdir(controller, from, true)) < 0) {
505 int cg_get_path(const char *controller, const char *path, const char *suffix, char **fs) {
508 static __thread bool good = false;
513 if (_unlikely_(!good)) {
516 r = path_is_mount_point("/sys/fs/cgroup", false);
518 return r < 0 ? r : -ENOENT;
520 /* Cache this to save a few stat()s */
524 if (isempty(controller))
527 /* This is a very minimal lookup from controller names to
528 * paths. Since we have mounted most hierarchies ourselves
529 * should be kinda safe, but eventually we might want to
530 * extend this to have a fallback to actually check
531 * /proc/mounts. Might need caching then. */
533 if (streq(controller, SYSTEMD_CGROUP_CONTROLLER))
535 else if (startswith(controller, "name="))
541 t = join("/sys/fs/cgroup/", p, "/", path, "/", suffix, NULL);
543 t = join("/sys/fs/cgroup/", p, "/", path, NULL);
545 t = join("/sys/fs/cgroup/", p, "/", suffix, NULL);
547 t = join("/sys/fs/cgroup/", p, NULL);
552 path_kill_slashes(t);
558 static int trim_cb(const char *path, const struct stat *sb, int typeflag, struct FTW *ftwbuf) {
562 if (typeflag != FTW_DP)
565 if (ftwbuf->level < 1)
568 p = strappend(path, "/tasks");
574 is_sticky = file_is_priv_sticky(p) > 0;
584 int cg_trim(const char *controller, const char *path, bool delete_root) {
591 r = cg_get_path(controller, path, NULL, &fs);
596 if (nftw(fs, trim_cb, 64, FTW_DEPTH|FTW_MOUNT|FTW_PHYS) < 0)
597 r = errno ? -errno : -EIO;
603 p = strappend(fs, "/tasks");
609 is_sticky = file_is_priv_sticky(p) > 0;
613 if (rmdir(fs) < 0 && errno != ENOENT) {
624 int cg_delete(const char *controller, const char *path) {
631 if ((r = parent_of_path(path, &parent)) < 0)
634 r = cg_migrate_recursive(controller, path, parent, false, true);
637 return r == -ENOENT ? 0 : r;
640 int cg_attach(const char *controller, const char *path, pid_t pid) {
649 if ((r = cg_get_path(controller, path, "tasks", &fs)) < 0)
655 snprintf(c, sizeof(c), "%lu\n", (unsigned long) pid);
658 r = write_one_line_file(fs, c);
664 int cg_set_group_access(const char *controller, const char *path, mode_t mode, uid_t uid, gid_t gid) {
671 if (mode != (mode_t) -1)
674 r = cg_get_path(controller, path, NULL, &fs);
678 r = chmod_and_chown(fs, mode, uid, gid);
684 int cg_set_task_access(const char *controller, const char *path, mode_t mode, uid_t uid, gid_t gid, int sticky) {
691 if (mode == (mode_t) -1 && uid == (uid_t) -1 && gid == (gid_t) -1 && sticky < 0)
694 if (mode != (mode_t) -1)
697 r = cg_get_path(controller, path, "tasks", &fs);
701 if (sticky >= 0 && mode != (mode_t) -1)
702 /* Both mode and sticky param are passed */
703 mode |= (sticky ? S_ISVTX : 0);
704 else if ((sticky >= 0 && mode == (mode_t) -1) ||
705 (mode != (mode_t) -1 && sticky < 0)) {
708 /* Only one param is passed, hence read the current
709 * mode from the file itself */
717 if (mode == (mode_t) -1)
718 /* No mode set, we just shall set the sticky bit */
719 mode = (st.st_mode & ~S_ISVTX) | (sticky ? S_ISVTX : 0);
721 /* Only mode set, leave sticky bit untouched */
722 mode = (st.st_mode & ~0777) | mode;
725 r = chmod_and_chown(fs, mode, uid, gid);
731 int cg_get_by_pid(const char *controller, pid_t pid, char **path) {
745 if (asprintf(&fs, "/proc/%lu/cgroup", (unsigned long) pid) < 0)
752 return errno == ENOENT ? -ESRCH : -errno;
754 cs = strlen(controller);
761 if (!(fgets(line, sizeof(line), f))) {
765 r = errno ? -errno : -EIO;
771 if (!(l = strchr(line, ':')))
775 if (strncmp(l, controller, cs) != 0)
781 if (!(p = strdup(l + cs + 1))) {
799 int cg_install_release_agent(const char *controller, const char *agent) {
800 char *fs = NULL, *contents = NULL, *line = NULL, *sc;
806 if ((r = cg_get_path(controller, NULL, "release_agent", &fs)) < 0)
809 if ((r = read_one_line_file(fs, &contents)) < 0)
812 sc = strstrip(contents);
815 if (asprintf(&line, "%s\n", agent) < 0) {
820 if ((r = write_one_line_file(fs, line)) < 0)
823 } else if (!streq(sc, agent)) {
830 if ((r = cg_get_path(controller, NULL, "notify_on_release", &fs)) < 0)
835 if ((r = read_one_line_file(fs, &contents)) < 0)
838 sc = strstrip(contents);
840 if (streq(sc, "0")) {
841 if ((r = write_one_line_file(fs, "1\n")) < 0)
845 } else if (!streq(sc, "1")) {
859 int cg_is_empty(const char *controller, const char *path, bool ignore_self) {
868 if ((r = cg_enumerate_tasks(controller, path, &f)) < 0)
869 return r == -ENOENT ? 1 : r;
871 while ((r = cg_read_pid(f, &pid)) > 0) {
873 if (ignore_self && pid == getpid())
888 int cg_is_empty_recursive(const char *controller, const char *path, bool ignore_self) {
896 if ((r = cg_is_empty(controller, path, ignore_self)) <= 0)
899 if ((r = cg_enumerate_subgroups(controller, path, &d)) < 0)
900 return r == -ENOENT ? 1 : r;
902 while ((r = cg_read_subgroup(d, &fn)) > 0) {
905 r = asprintf(&p, "%s/%s", path, fn);
913 r = cg_is_empty_recursive(controller, p, ignore_self);
931 int cg_split_spec(const char *spec, char **controller, char **path) {
933 char *t = NULL, *u = NULL;
936 assert(controller || path);
941 if (!(t = strdup(spec)))
953 if (!(e = strchr(spec, ':'))) {
955 if (strchr(spec, '/') || spec[0] == 0)
959 if (!(t = strdup(spec)))
973 memchr(spec, '/', e-spec))
977 if (!(t = strndup(spec, e-spec)))
981 if (!(u = strdup(e+1))) {
995 int cg_join_spec(const char *controller, const char *path, char **spec) {
999 if (!path_is_absolute(path) ||
1000 controller[0] == 0 ||
1001 strchr(controller, ':') ||
1002 strchr(controller, '/'))
1005 if (asprintf(spec, "%s:%s", controller, path) < 0)
1011 int cg_fix_path(const char *path, char **result) {
1018 /* First check if it already is a filesystem path */
1019 if (path_is_absolute(path) &&
1020 path_startswith(path, "/sys/fs/cgroup") &&
1021 access(path, F_OK) >= 0) {
1023 if (!(t = strdup(path)))
1030 /* Otherwise treat it as cg spec */
1031 if ((r = cg_split_spec(path, &c, &p)) < 0)
1034 r = cg_get_path(c ? c : SYSTEMD_CGROUP_CONTROLLER, p ? p : "/", NULL, result);
1041 int cg_get_user_path(char **path) {
1046 /* Figure out the place to put user cgroups below. We use the
1047 * same as PID 1 has but with the "/system" suffix replaced by
1050 if (cg_get_by_pid(SYSTEMD_CGROUP_CONTROLLER, 1, &root) < 0)
1051 p = strdup("/user");
1053 if (endswith(root, "/system"))
1054 root[strlen(root) - 7] = 0;
1055 else if (streq(root, "/"))
1058 p = strappend(root, "/user");