diff options
Diffstat (limited to 'src/shared/cgroup-util.c')
| -rw-r--r-- | src/shared/cgroup-util.c | 252 |
1 files changed, 252 insertions, 0 deletions
diff --git a/src/shared/cgroup-util.c b/src/shared/cgroup-util.c new file mode 100644 index 0000000000..af6ce959c1 --- /dev/null +++ b/src/shared/cgroup-util.c @@ -0,0 +1,252 @@ +/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ + +/*** + 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 Lesser General Public License as published by + the Free Software Foundation; either version 2.1 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 + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with systemd; If not, see <http://www.gnu.org/licenses/>. +***/ + +#include <errno.h> +#include <signal.h> +#include <string.h> +#include <stdlib.h> +#include <sys/types.h> + +#include "cgroup-util.h" +#include "set.h" +#include "path-util.h" + +int cg_enumerate_processes(const char *controller, const char *path, FILE **_f) { + _cleanup_free_ char *fs = NULL; + FILE *f; + int r; + + assert(_f); + + r = cg_get_path(controller, path, "cgroup.procs", &fs); + if (r < 0) + return r; + + f = fopen(fs, "re"); + if (!f) + return -errno; + + *_f = f; + return 0; +} + +int cg_read_pid(FILE *f, pid_t *_pid) { + unsigned long ul; + + /* Note that the cgroup.procs might contain duplicates! See + * cgroups.txt for details. */ + + assert(f); + assert(_pid); + + errno = 0; + if (fscanf(f, "%lu", &ul) != 1) { + + if (feof(f)) + return 0; + + return errno ? -errno : -EIO; + } + + if (ul <= 0) + return -EIO; + + *_pid = (pid_t) ul; + return 1; +} + +int cg_kill(const char *controller, const char *path, int sig, bool sigcont, bool ignore_self, Set *s) { + _cleanup_set_free_ Set *allocated_set = NULL; + bool done = false; + int r, ret = 0; + pid_t my_pid; + + assert(sig >= 0); + + /* This goes through the tasks list and kills them all. This + * is repeated until no further processes are added to the + * tasks list, to properly handle forking processes */ + + if (!s) { + s = allocated_set = set_new(trivial_hash_func, trivial_compare_func); + if (!s) + return -ENOMEM; + } + + my_pid = getpid(); + + do { + _cleanup_fclose_ FILE *f = NULL; + pid_t pid = 0; + done = true; + + r = cg_enumerate_processes(controller, path, &f); + if (r < 0) { + if (ret >= 0 && r != -ENOENT) + return r; + + return ret; + } + + while ((r = cg_read_pid(f, &pid)) > 0) { + + if (ignore_self && pid == my_pid) + continue; + + if (set_get(s, LONG_TO_PTR(pid)) == LONG_TO_PTR(pid)) + continue; + + /* If we haven't killed this process yet, kill + * it */ + if (kill(pid, sig) < 0) { + if (ret >= 0 && errno != ESRCH) + ret = -errno; + } else if (ret == 0) { + + if (sigcont) + kill(pid, SIGCONT); + + ret = 1; + } + + done = false; + + r = set_put(s, LONG_TO_PTR(pid)); + if (r < 0) { + if (ret >= 0) + return r; + + return ret; + } + } + + if (r < 0) { + if (ret >= 0) + return r; + + return ret; + } + + /* 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); + + return ret; +} + +static const char *normalize_controller(const char *controller) { + + assert(controller); + + if (streq(controller, SYSTEMD_CGROUP_CONTROLLER)) + return "systemd"; + else if (startswith(controller, "name=")) + return controller + 5; + else + return controller; +} + +static int join_path(const char *controller, const char *path, const char *suffix, char **fs) { + char *t = NULL; + + if (!isempty(controller)) { + if (!isempty(path) && !isempty(suffix)) + t = strjoin("/sys/fs/cgroup/", controller, "/", path, "/", suffix, NULL); + else if (!isempty(path)) + t = strjoin("/sys/fs/cgroup/", controller, "/", path, NULL); + else if (!isempty(suffix)) + t = strjoin("/sys/fs/cgroup/", controller, "/", suffix, NULL); + else + t = strappend("/sys/fs/cgroup/", controller); + } else { + if (!isempty(path) && !isempty(suffix)) + t = strjoin(path, "/", suffix, NULL); + else if (!isempty(path)) + t = strdup(path); + else + return -EINVAL; + } + + if (!t) + return -ENOMEM; + + path_kill_slashes(t); + + *fs = t; + return 0; +} + +int cg_get_path(const char *controller, const char *path, const char *suffix, char **fs) { + const char *p; + static thread_local bool good = false; + + assert(fs); + + if (controller && !cg_controller_is_valid(controller, true)) + return -EINVAL; + + if (_unlikely_(!good)) { + int r; + + r = path_is_mount_point("/sys/fs/cgroup", false); + if (r <= 0) + return r < 0 ? r : -ENOENT; + + /* Cache this to save a few stat()s */ + good = true; + } + + p = controller ? normalize_controller(controller) : NULL; + + return join_path(p, path, suffix, fs); +} + + +#define CONTROLLER_VALID \ + DIGITS LETTERS \ + "_" + +bool cg_controller_is_valid(const char *p, bool allow_named) { + const char *t, *s; + + if (!p) + return false; + + if (allow_named) { + s = startswith(p, "name="); + if (s) + p = s; + } + + if (*p == 0 || *p == '_') + return false; + + for (t = p; *t; t++) + if (!strchr(CONTROLLER_VALID, *t)) + return false; + + if (t - p > FILENAME_MAX) + return false; + + return true; +} |