diff options
Diffstat (limited to 'src/cgroup.c')
| -rw-r--r-- | src/cgroup.c | 561 |
1 files changed, 561 insertions, 0 deletions
diff --git a/src/cgroup.c b/src/cgroup.c new file mode 100644 index 0000000000..301fc949da --- /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; +} |