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) {
46 r = cg_get_path(controller, path, "cgroup.procs", &fs);
60 int cg_enumerate_tasks(const char *controller, const char *path, FILE **_f) {
68 r = cg_get_path(controller, path, "tasks", &fs);
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) {
112 /* This is not recursive! */
114 r = cg_get_path(controller, path, NULL, &fs);
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 static const char *normalize_controller(const char *controller) {
507 if (streq(controller, SYSTEMD_CGROUP_CONTROLLER))
509 else if (startswith(controller, "name="))
510 return controller + 5;
515 static int join_path(const char *controller, const char *path, const char *suffix, char **fs) {
518 if (!(controller || path))
523 t = join("/sys/fs/cgroup/", controller, "/", path, "/", suffix, NULL);
525 t = join("/sys/fs/cgroup/", controller, "/", path, NULL);
527 t = join("/sys/fs/cgroup/", controller, "/", suffix, NULL);
529 t = join("/sys/fs/cgroup/", controller, NULL);
532 t = join(path, "/", suffix, NULL);
540 path_kill_slashes(t);
546 int cg_get_path(const char *controller, const char *path, const char *suffix, char **fs) {
548 static __thread bool good = false;
552 if (_unlikely_(!good)) {
555 r = path_is_mount_point("/sys/fs/cgroup", false);
557 return r < 0 ? r : -ENOENT;
559 /* Cache this to save a few stat()s */
563 p = controller ? normalize_controller(controller) : NULL;
564 return join_path(p, path, suffix, fs);
567 int cg_get_path_and_check(const char *controller, const char *path, const char *suffix, char **fs) {
574 if (isempty(controller))
577 p = normalize_controller(controller);
579 /* Check if this controller actually really exists */
580 cc = alloca(sizeof("/sys/fs/cgroup/") + strlen(p));
581 strcpy(stpcpy(cc, "/sys/fs/cgroup/"), p);
582 if (access(cc, F_OK) < 0)
585 return join_path(p, path, suffix, fs);
588 static int trim_cb(const char *path, const struct stat *sb, int typeflag, struct FTW *ftwbuf) {
592 if (typeflag != FTW_DP)
595 if (ftwbuf->level < 1)
598 p = strappend(path, "/tasks");
604 is_sticky = file_is_priv_sticky(p) > 0;
614 int cg_trim(const char *controller, const char *path, bool delete_root) {
621 r = cg_get_path(controller, path, NULL, &fs);
626 if (nftw(fs, trim_cb, 64, FTW_DEPTH|FTW_MOUNT|FTW_PHYS) < 0)
627 r = errno ? -errno : -EIO;
633 p = strappend(fs, "/tasks");
639 is_sticky = file_is_priv_sticky(p) > 0;
643 if (rmdir(fs) < 0 && errno != ENOENT) {
654 int cg_delete(const char *controller, const char *path) {
661 if ((r = parent_of_path(path, &parent)) < 0)
664 r = cg_migrate_recursive(controller, path, parent, false, true);
667 return r == -ENOENT ? 0 : r;
670 int cg_attach(const char *controller, const char *path, pid_t pid) {
679 r = cg_get_path_and_check(controller, path, "tasks", &fs);
686 snprintf(c, sizeof(c), "%lu\n", (unsigned long) pid);
689 r = write_one_line_file(fs, c);
695 int cg_set_group_access(const char *controller, const char *path, mode_t mode, uid_t uid, gid_t gid) {
702 if (mode != (mode_t) -1)
705 r = cg_get_path(controller, path, NULL, &fs);
709 r = chmod_and_chown(fs, mode, uid, gid);
715 int cg_set_task_access(const char *controller, const char *path, mode_t mode, uid_t uid, gid_t gid, int sticky) {
722 if (mode == (mode_t) -1 && uid == (uid_t) -1 && gid == (gid_t) -1 && sticky < 0)
725 if (mode != (mode_t) -1)
728 r = cg_get_path(controller, path, "tasks", &fs);
732 if (sticky >= 0 && mode != (mode_t) -1)
733 /* Both mode and sticky param are passed */
734 mode |= (sticky ? S_ISVTX : 0);
735 else if ((sticky >= 0 && mode == (mode_t) -1) ||
736 (mode != (mode_t) -1 && sticky < 0)) {
739 /* Only one param is passed, hence read the current
740 * mode from the file itself */
748 if (mode == (mode_t) -1)
749 /* No mode set, we just shall set the sticky bit */
750 mode = (st.st_mode & ~S_ISVTX) | (sticky ? S_ISVTX : 0);
752 /* Only mode set, leave sticky bit untouched */
753 mode = (st.st_mode & ~0777) | mode;
756 r = chmod_and_chown(fs, mode, uid, gid);
762 int cg_get_by_pid(const char *controller, pid_t pid, char **path) {
776 if (asprintf(&fs, "/proc/%lu/cgroup", (unsigned long) pid) < 0)
783 return errno == ENOENT ? -ESRCH : -errno;
785 cs = strlen(controller);
792 if (!(fgets(line, sizeof(line), f))) {
796 r = errno ? -errno : -EIO;
802 if (!(l = strchr(line, ':')))
806 if (strncmp(l, controller, cs) != 0)
812 if (!(p = strdup(l + cs + 1))) {
830 int cg_install_release_agent(const char *controller, const char *agent) {
831 char *fs = NULL, *contents = NULL, *line = NULL, *sc;
837 if ((r = cg_get_path(controller, NULL, "release_agent", &fs)) < 0)
840 if ((r = read_one_line_file(fs, &contents)) < 0)
843 sc = strstrip(contents);
846 if (asprintf(&line, "%s\n", agent) < 0) {
851 if ((r = write_one_line_file(fs, line)) < 0)
854 } else if (!streq(sc, agent)) {
861 if ((r = cg_get_path(controller, NULL, "notify_on_release", &fs)) < 0)
866 if ((r = read_one_line_file(fs, &contents)) < 0)
869 sc = strstrip(contents);
871 if (streq(sc, "0")) {
872 if ((r = write_one_line_file(fs, "1\n")) < 0)
876 } else if (!streq(sc, "1")) {
890 int cg_is_empty(const char *controller, const char *path, bool ignore_self) {
891 pid_t pid = 0, self_pid;
898 r = cg_enumerate_tasks(controller, path, &f);
900 return r == -ENOENT ? 1 : r;
904 while ((r = cg_read_pid(f, &pid)) > 0) {
906 if (ignore_self && pid == self_pid)
921 int cg_is_empty_recursive(const char *controller, const char *path, bool ignore_self) {
928 r = cg_is_empty(controller, path, ignore_self);
932 r = cg_enumerate_subgroups(controller, path, &d);
934 return r == -ENOENT ? 1 : r;
936 while ((r = cg_read_subgroup(d, &fn)) > 0) {
939 r = asprintf(&p, "%s/%s", path, fn);
947 r = cg_is_empty_recursive(controller, p, ignore_self);
965 int cg_split_spec(const char *spec, char **controller, char **path) {
967 char *t = NULL, *u = NULL;
970 assert(controller || path);
975 if (!(t = strdup(spec)))
987 if (!(e = strchr(spec, ':'))) {
989 if (strchr(spec, '/') || spec[0] == 0)
993 if (!(t = strdup(spec)))
1007 memchr(spec, '/', e-spec))
1011 if (!(t = strndup(spec, e-spec)))
1015 if (!(u = strdup(e+1))) {
1029 int cg_join_spec(const char *controller, const char *path, char **spec) {
1033 if (!path_is_absolute(path) ||
1034 controller[0] == 0 ||
1035 strchr(controller, ':') ||
1036 strchr(controller, '/'))
1039 if (asprintf(spec, "%s:%s", controller, path) < 0)
1045 int cg_fix_path(const char *path, char **result) {
1052 /* First check if it already is a filesystem path */
1053 if (path_startswith(path, "/sys/fs/cgroup") &&
1054 access(path, F_OK) >= 0) {
1064 /* Otherwise treat it as cg spec */
1065 r = cg_split_spec(path, &c, &p);
1069 r = cg_get_path(c ? c : SYSTEMD_CGROUP_CONTROLLER, p ? p : "/", NULL, result);
1076 int cg_get_user_path(char **path) {
1081 /* Figure out the place to put user cgroups below. We use the
1082 * same as PID 1 has but with the "/system" suffix replaced by
1085 if (cg_get_by_pid(SYSTEMD_CGROUP_CONTROLLER, 1, &root) < 0)
1086 p = strdup("/user");
1088 if (endswith(root, "/system"))
1089 root[strlen(root) - 7] = 0;
1090 else if (streq(root, "/"))
1093 p = strappend(root, "/user");