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-rw-r--r--src/cgroup.c561
1 files changed, 561 insertions, 0 deletions
diff --git a/src/cgroup.c b/src/cgroup.c
new file mode 100644
index 000000000..301fc949d
--- /dev/null
+++ b/src/cgroup.c
@@ -0,0 +1,561 @@
+/*-*- Mode: C; c-basic-offset: 8 -*-*/
+
+/***
+ This file is part of systemd.
+
+ Copyright 2010 Lennart Poettering
+
+ systemd is free software; you can redistribute it and/or modify it
+ under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 2 of the License, or
+ (at your option) any later version.
+
+ systemd is distributed in the hope that it will be useful, but
+ WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <errno.h>
+#include <assert.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <signal.h>
+#include <sys/mount.h>
+
+#include "cgroup.h"
+#include "log.h"
+
+static int translate_error(int error, int _errno) {
+
+ switch (error) {
+
+ case ECGROUPNOTCOMPILED:
+ case ECGROUPNOTMOUNTED:
+ case ECGROUPNOTEXIST:
+ case ECGROUPNOTCREATED:
+ return -ENOENT;
+
+ case ECGINVAL:
+ return -EINVAL;
+
+ case ECGROUPNOTALLOWED:
+ return -EPERM;
+
+ case ECGOTHER:
+ return -_errno;
+ }
+
+ return -EIO;
+}
+
+int cgroup_bonding_realize(CGroupBonding *b) {
+ int r;
+
+ assert(b);
+ assert(b->path);
+ assert(b->controller);
+
+ if (b->cgroup)
+ return 0;
+
+ if (!(b->cgroup = cgroup_new_cgroup(b->path)))
+ return -ENOMEM;
+
+ if (!cgroup_add_controller(b->cgroup, b->controller)) {
+ r = -ENOMEM;
+ goto fail;
+ }
+
+ if (b->inherit)
+ r = cgroup_create_cgroup_from_parent(b->cgroup, true);
+ else
+ r = cgroup_create_cgroup(b->cgroup, true);
+
+ if (r != 0) {
+ r = translate_error(r, errno);
+ goto fail;
+ }
+
+ return 0;
+
+fail:
+ cgroup_free(&b->cgroup);
+ b->cgroup = NULL;
+ return r;
+}
+
+int cgroup_bonding_realize_list(CGroupBonding *first) {
+ CGroupBonding *b;
+
+ LIST_FOREACH(by_unit, b, first) {
+ int r;
+
+ if ((r = cgroup_bonding_realize(b)) < 0)
+ return r;
+ }
+
+ return 0;
+}
+
+void cgroup_bonding_free(CGroupBonding *b) {
+ assert(b);
+
+ if (b->unit) {
+ CGroupBonding *f;
+
+ LIST_REMOVE(CGroupBonding, by_unit, b->unit->meta.cgroup_bondings, b);
+
+ assert_se(f = hashmap_get(b->unit->meta.manager->cgroup_bondings, b->path));
+ LIST_REMOVE(CGroupBonding, by_path, f, b);
+
+ if (f)
+ hashmap_replace(b->unit->meta.manager->cgroup_bondings, b->path, f);
+ else
+ hashmap_remove(b->unit->meta.manager->cgroup_bondings, b->path);
+ }
+
+ if (b->cgroup) {
+ if (b->only_us && b->clean_up && cgroup_bonding_is_empty(b) > 0)
+ cgroup_delete_cgroup_ext(b->cgroup, true);
+
+ cgroup_free(&b->cgroup);
+ }
+
+ free(b->controller);
+ free(b->path);
+ free(b);
+}
+
+void cgroup_bonding_free_list(CGroupBonding *first) {
+ CGroupBonding *b, *n;
+
+ LIST_FOREACH_SAFE(by_unit, b, n, first)
+ cgroup_bonding_free(b);
+}
+
+int cgroup_bonding_install(CGroupBonding *b, pid_t pid) {
+ int r;
+
+ assert(b);
+ assert(pid >= 0);
+
+ if (pid == 0)
+ pid = getpid();
+
+ if (!b->cgroup)
+ return -ENOENT;
+
+ if ((r = cgroup_attach_task_pid(b->cgroup, pid)))
+ return translate_error(r, errno);
+
+ return 0;
+}
+
+int cgroup_bonding_install_list(CGroupBonding *first, pid_t pid) {
+ CGroupBonding *b;
+
+ LIST_FOREACH(by_unit, b, first) {
+ int r;
+
+ if ((r = cgroup_bonding_install(b, pid)) < 0)
+ return r;
+ }
+
+ return 0;
+}
+
+int cgroup_bonding_kill(CGroupBonding *b, int sig) {
+ int r;
+ Set *s;
+ bool done;
+ bool killed = false;
+
+ assert(b);
+ assert(sig > 0);
+
+ if (!b->only_us)
+ return -EAGAIN;
+
+ if (!(s = set_new(trivial_hash_func, trivial_compare_func)))
+ return -ENOMEM;
+
+ do {
+ void *iterator;
+ pid_t pid;
+
+ done = true;
+
+ if ((r = cgroup_get_task_begin(b->path, b->controller, &iterator, &pid)) != 0) {
+ if (r == ECGEOF) {
+ r = 0;
+ goto kill_done;
+ } else {
+ r = translate_error(r, errno);
+ break;
+ }
+ }
+
+ for (;;) {
+ if (set_get(s, INT_TO_PTR(pid)) != INT_TO_PTR(pid)) {
+
+ /* If we haven't killed this process
+ * yet, kill it */
+
+ if (kill(pid, sig) < 0 && errno != ESRCH) {
+ r = -errno;
+ break;
+ }
+
+ killed = true;
+ done = false;
+
+ if ((r = set_put(s, INT_TO_PTR(pid))) < 0)
+ break;
+ }
+
+ if ((r = cgroup_get_task_next(&iterator, &pid)) != 0) {
+
+ if (r == ECGEOF)
+ r = 0;
+ else
+ r = translate_error(r, errno);
+
+ break;
+ }
+ }
+
+ kill_done:
+ assert_se(cgroup_get_task_end(&iterator) == 0);
+
+ /* To avoid racing against processes which fork
+ * quicker than we can kill them we repeat this until
+ * no new pids need to be killed. */
+
+ } while (!done && r >= 0);
+
+ set_free(s);
+
+ if (r < 0)
+ return r;
+
+ return killed ? 0 : -ESRCH;
+}
+
+int cgroup_bonding_kill_list(CGroupBonding *first, int sig) {
+ CGroupBonding *b;
+ int r = -EAGAIN;
+
+ LIST_FOREACH(by_unit, b, first) {
+ if ((r = cgroup_bonding_kill(b, sig)) < 0) {
+ if (r == -EAGAIN || -ESRCH)
+ continue;
+
+ return r;
+ }
+
+ return 0;
+ }
+
+ return r;
+}
+
+/* Returns 1 if the group is empty, 0 if it is not, -EAGAIN if we
+ * cannot know */
+int cgroup_bonding_is_empty(CGroupBonding *b) {
+ void *iterator;
+ pid_t pid;
+ int r;
+
+ assert(b);
+
+ r = cgroup_get_task_begin(b->path, b->controller, &iterator, &pid);
+
+ if (r == 0 || r == ECGEOF)
+ cgroup_get_task_end(&iterator);
+
+ /* Hmm, no PID in this group? Then it is definitely empty */
+ if (r == ECGEOF)
+ return 1;
+
+ /* Some error? Let's return it */
+ if (r != 0)
+ return translate_error(r, errno);
+
+ /* It's not empty, and we are the only user, then it is
+ * definitely not empty */
+ if (b->only_us)
+ return 0;
+
+ /* There are PIDs in the group but we aren't the only users,
+ * hence we cannot say */
+ return -EAGAIN;
+}
+
+int cgroup_bonding_is_empty_list(CGroupBonding *first) {
+ CGroupBonding *b;
+
+ LIST_FOREACH(by_unit, b, first) {
+ int r;
+
+ if ((r = cgroup_bonding_is_empty(b)) < 0) {
+ /* If this returned -EAGAIN, then we don't know if the
+ * group is empty, so let's see if another group can
+ * tell us */
+
+ if (r != -EAGAIN)
+ return r;
+ } else
+ return r;
+ }
+
+ return -EAGAIN;
+}
+
+static int install_release_agent(Manager *m, const char *mount_point) {
+ char *p, *c, *sc;
+ int r;
+
+ assert(m);
+ assert(mount_point);
+
+ if (asprintf(&p, "%s/release_agent", mount_point) < 0)
+ return -ENOMEM;
+
+ if ((r = read_one_line_file(p, &c)) < 0) {
+ free(p);
+ return r;
+ }
+
+ sc = strstrip(c);
+
+ if (sc[0] == 0) {
+ if ((r = write_one_line_file(p, CGROUP_AGENT_PATH "\n" )) < 0) {
+ free(p);
+ free(c);
+ return r;
+ }
+ } else if (!streq(sc, CGROUP_AGENT_PATH)) {
+ free(p);
+ free(c);
+ return -EEXIST;
+ }
+
+ free(c);
+ free(p);
+
+ if (asprintf(&p, "%s/notify_on_release", mount_point) < 0)
+ return -ENOMEM;
+
+ if ((r = read_one_line_file(p, &c)) < 0) {
+ free(p);
+ return r;
+ }
+
+ sc = strstrip(c);
+
+ if (streq(sc, "0")) {
+ if ((r = write_one_line_file(p, "1\n")) < 0) {
+ free(p);
+ free(c);
+ return r;
+ }
+ } else if (!streq(sc, "1")) {
+ free(p);
+ free(c);
+ return -EIO;
+ }
+
+ free(p);
+ free(c);
+
+ return 0;
+}
+
+static int create_hierarchy_cgroup(Manager *m) {
+ struct cgroup *cg;
+ int r;
+
+ assert(m);
+
+ if (!(cg = cgroup_new_cgroup(m->cgroup_hierarchy)))
+ return -ENOMEM;
+
+ if (!(cgroup_add_controller(cg, m->cgroup_controller))) {
+ r = -ENOMEM;
+ goto finish;
+ }
+
+ if ((r = cgroup_create_cgroup(cg, true)) != 0) {
+ log_error("Failed to create cgroup hierarchy group: %s", cgroup_strerror(r));
+ r = translate_error(r, errno);
+ goto finish;
+ }
+
+ if ((r = cgroup_attach_task(cg)) != 0) {
+ log_error("Failed to add ourselves to hierarchy group: %s", cgroup_strerror(r));
+ r = translate_error(r, errno);
+ goto finish;
+ }
+
+ r = 0;
+
+finish:
+ cgroup_free(&cg);
+ return r;
+}
+
+int manager_setup_cgroup(Manager *m) {
+ char *mp, *cp;
+ int r;
+ pid_t pid;
+ char suffix[32];
+
+ assert(m);
+
+ if ((r = cgroup_init()) != 0) {
+ log_error("Failed to initialize libcg: %s", cgroup_strerror(r));
+ return translate_error(r, errno);
+ }
+
+ free(m->cgroup_controller);
+ if (!(m->cgroup_controller = strdup("debug")))
+ return -ENOMEM;
+
+ if ((r = cgroup_get_subsys_mount_point(m->cgroup_controller, &mp)))
+ return translate_error(r, errno);
+
+ pid = getpid();
+
+ if ((r = cgroup_get_current_controller_path(pid, m->cgroup_controller, &cp))) {
+ free(mp);
+ return translate_error(r, errno);
+ }
+
+ snprintf(suffix, sizeof(suffix), "/systemd-%u", (unsigned) pid);
+ char_array_0(suffix);
+
+ free(m->cgroup_hierarchy);
+
+ if (endswith(cp, suffix))
+ /* We probably got reexecuted and can continue to use our root cgroup */
+ m->cgroup_hierarchy = cp;
+ else {
+ /* We need a new root cgroup */
+
+ m->cgroup_hierarchy = NULL;
+ r = asprintf(&m->cgroup_hierarchy, "%s%s", streq(cp, "/") ? "" : cp, suffix);
+ free(cp);
+
+ if (r < 0) {
+ free(mp);
+ return -ENOMEM;
+ }
+ }
+
+ log_debug("Using cgroup controller <%s>, hierarchy mounted at <%s>, using root group <%s>.",
+ m->cgroup_controller,
+ mp,
+ m->cgroup_hierarchy);
+
+ if ((r = install_release_agent(m, mp)) < 0)
+ log_warning("Failed to install release agent, ignoring: %s", strerror(-r));
+ else
+ log_debug("Installed release agent, or already installed.");
+
+ free(mp);
+
+ if ((r = create_hierarchy_cgroup(m)) < 0)
+ log_error("Failed to create root cgroup hierarchy: %s", strerror(-r));
+ else
+ log_debug("Created root group.");
+
+ return r;
+}
+
+int manager_shutdown_cgroup(Manager *m, bool delete) {
+ struct cgroup *cg;
+ int r;
+
+ assert(m);
+
+ if (!m->cgroup_hierarchy)
+ return 0;
+
+ if (!(cg = cgroup_new_cgroup(m->cgroup_hierarchy)))
+ return -ENOMEM;
+
+ if (!(cgroup_add_controller(cg, m->cgroup_controller))) {
+ r = -ENOMEM;
+ goto finish;
+ }
+
+ /* Often enough we won't be able to delete the cgroup we
+ * ourselves are in, hence ignore all errors here */
+ if (delete)
+ cgroup_delete_cgroup_ext(cg, CGFLAG_DELETE_IGNORE_MIGRATION|CGFLAG_DELETE_RECURSIVE);
+ r = 0;
+
+finish:
+ cgroup_free(&cg);
+ return r;
+
+}
+
+int cgroup_notify_empty(Manager *m, const char *group) {
+ CGroupBonding *l, *b;
+
+ assert(m);
+ assert(group);
+
+ if (!(l = hashmap_get(m->cgroup_bondings, group)))
+ return 0;
+
+ LIST_FOREACH(by_path, b, l) {
+ int t;
+
+ if (!b->unit)
+ continue;
+
+ if ((t = cgroup_bonding_is_empty_list(b)) < 0) {
+
+ /* If we don't know, we don't know */
+ if (t != -EAGAIN)
+ log_warning("Failed to check whether cgroup is empty: %s", strerror(errno));
+
+ continue;
+ }
+
+ if (t > 0)
+ if (UNIT_VTABLE(b->unit)->cgroup_notify_empty)
+ UNIT_VTABLE(b->unit)->cgroup_notify_empty(b->unit);
+ }
+
+ return 0;
+}
+
+CGroupBonding *cgroup_bonding_find_list(CGroupBonding *first, const char *controller) {
+ CGroupBonding *b;
+
+ assert(controller);
+
+ LIST_FOREACH(by_unit, b, first)
+ if (streq(b->controller, controller))
+ return b;
+
+ return NULL;
+}
+
+char *cgroup_bonding_to_string(CGroupBonding *b) {
+ char *r;
+
+ assert(b);
+
+ if (asprintf(&r, "%s:%s", b->controller, b->path) < 0)
+ return NULL;
+
+ return r;
+}
generated by cgit v1.2.3 (git 2.25.1) at 2024-06-24 06:14:14 +0000