Imported Upstream version 204

1 files changed, 1603 insertions, 0 deletions

diff --git a/src/shared/cgroup-util.c b/src/shared/cgroup-util.c
new file mode 100644
index 0000000000..43c415d760
--- /dev/null
+++ b/src/shared/cgroup-util.c
@@ -0,0 +1,1603 @@
+/*-*- 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 <unistd.h>
+#include <signal.h>
+#include <string.h>
+#include <stdlib.h>
+#include <dirent.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <ftw.h>
+
+#include "cgroup-util.h"
+#include "log.h"
+#include "set.h"
+#include "macro.h"
+#include "util.h"
+#include "path-util.h"
+#include "strv.h"
+#include "unit-name.h"
+#include "fileio.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_enumerate_tasks(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, "tasks", &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_enumerate_subgroups(const char *controller, const char *path, DIR **_d) {
+        _cleanup_free_ char *fs = NULL;
+        int r;
+        DIR *d;
+
+        assert(_d);
+
+        /* This is not recursive! */
+
+        r = cg_get_path(controller, path, NULL, &fs);
+        if (r < 0)
+                return r;
+
+        d = opendir(fs);
+        if (!d)
+                return -errno;
+
+        *_d = d;
+        return 0;
+}
+
+int cg_read_subgroup(DIR *d, char **fn) {
+        struct dirent *de;
+
+        assert(d);
+        assert(fn);
+
+        FOREACH_DIRENT(de, d, return -errno) {
+                char *b;
+
+                if (de->d_type != DT_DIR)
+                        continue;
+
+                if (streq(de->d_name, ".") ||
+                    streq(de->d_name, ".."))
+                        continue;
+
+                b = strdup(de->d_name);
+                if (!b)
+                        return -ENOMEM;
+
+                *fn = b;
+                return 1;
+        }
+
+        return 0;
+}
+
+int cg_rmdir(const char *controller, const char *path, bool honour_sticky) {
+        _cleanup_free_ char *p = NULL;
+        int r;
+
+        r = cg_get_path(controller, path, NULL, &p);
+        if (r < 0)
+                return r;
+
+        if (honour_sticky) {
+                char *tasks;
+
+                /* If the sticky bit is set don't remove the directory */
+
+                tasks = strappend(p, "/tasks");
+                if (!tasks)
+                        return -ENOMEM;
+
+                r = file_is_priv_sticky(tasks);
+                free(tasks);
+
+                if (r > 0)
+                        return 0;
+        }
+
+        r = rmdir(p);
+        if (r < 0 && errno != ENOENT)
+                return -errno;
+
+        return 0;
+}
+
+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;
+}
+
+int cg_kill_recursive(const char *controller, const char *path, int sig, bool sigcont, bool ignore_self, bool rem, Set *s) {
+        _cleanup_set_free_ Set *allocated_set = NULL;
+        _cleanup_closedir_ DIR *d = NULL;
+        int r, ret = 0;
+        char *fn;
+
+        assert(path);
+        assert(sig >= 0);
+
+        if (!s) {
+                s = allocated_set = set_new(trivial_hash_func, trivial_compare_func);
+                if (!s)
+                        return -ENOMEM;
+        }
+
+        ret = cg_kill(controller, path, sig, sigcont, ignore_self, s);
+
+        r = cg_enumerate_subgroups(controller, path, &d);
+        if (r < 0) {
+                if (ret >= 0 && r != -ENOENT)
+                        return r;
+
+                return ret;
+        }
+
+        while ((r = cg_read_subgroup(d, &fn)) > 0) {
+                _cleanup_free_ char *p = NULL;
+
+                p = strjoin(path, "/", fn, NULL);
+                free(fn);
+                if (!p)
+                        return -ENOMEM;
+
+                r = cg_kill_recursive(controller, p, sig, sigcont, ignore_self, rem, s);
+                if (ret >= 0 && r != 0)
+                        ret = r;
+        }
+
+        if (ret >= 0 && r < 0)
+                ret = r;
+
+        if (rem) {
+                r = cg_rmdir(controller, path, true);
+                if (r < 0 && ret >= 0 && r != -ENOENT && r != -EBUSY)
+                        return r;
+        }
+
+        return ret;
+}
+
+int cg_kill_recursive_and_wait(const char *controller, const char *path, bool rem) {
+        unsigned i;
+
+        assert(path);
+
+        /* This safely kills all processes; first it sends a SIGTERM,
+         * then checks 8 times after 200ms whether the group is now
+         * empty, then kills everything that is left with SIGKILL and
+         * finally checks 5 times after 200ms each whether the group
+         * is finally empty. */
+
+        for (i = 0; i < 15; i++) {
+                int sig, r;
+
+                if (i <= 0)
+                        sig = SIGTERM;
+                else if (i == 9)
+                        sig = SIGKILL;
+                else
+                        sig = 0;
+
+                r = cg_kill_recursive(controller, path, sig, true, true, rem, NULL);
+                if (r <= 0)
+                        return r;
+
+                usleep(200 * USEC_PER_MSEC);
+        }
+
+        return 0;
+}
+
+int cg_migrate(const char *cfrom, const char *pfrom, const char *cto, const char *pto, bool ignore_self) {
+        bool done = false;
+        _cleanup_set_free_ Set *s = NULL;
+        int r, ret = 0;
+        pid_t my_pid;
+
+        assert(cfrom);
+        assert(pfrom);
+        assert(cto);
+        assert(pto);
+
+        s = 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_tasks(cfrom, pfrom, &f);
+                if (r < 0) {
+                        if (ret >= 0 && r != -ENOENT)
+                                return r;
+
+                        return ret;
+                }
+
+                while ((r = cg_read_pid(f, &pid)) > 0) {
+
+                        /* This might do weird stuff if we aren't a
+                         * single-threaded program. However, we
+                         * luckily know we are not */
+                        if (ignore_self && pid == my_pid)
+                                continue;
+
+                        if (set_get(s, LONG_TO_PTR(pid)) == LONG_TO_PTR(pid))
+                                continue;
+
+                        r = cg_attach(cto, pto, pid);
+                        if (r < 0) {
+                                if (ret >= 0 && r != -ESRCH)
+                                        ret = r;
+                        } else if (ret == 0)
+                                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;
+                }
+        } while (!done);
+
+        return ret;
+}
+
+int cg_migrate_recursive(const char *cfrom, const char *pfrom, const char *cto, const char *pto, bool ignore_self, bool rem) {
+        _cleanup_closedir_ DIR *d = NULL;
+        int r, ret = 0;
+        char *fn;
+
+        assert(cfrom);
+        assert(pfrom);
+        assert(cto);
+        assert(pto);
+
+        ret = cg_migrate(cfrom, pfrom, cto, pto, ignore_self);
+
+        r = cg_enumerate_subgroups(cfrom, pfrom, &d);
+        if (r < 0) {
+                if (ret >= 0 && r != -ENOENT)
+                        return r;
+
+                return ret;
+        }
+
+        while ((r = cg_read_subgroup(d, &fn)) > 0) {
+                _cleanup_free_ char *p = NULL;
+
+                p = strjoin(pfrom, "/", fn, NULL);
+                free(fn);
+                if (!p) {
+                        if (ret >= 0)
+                                return -ENOMEM;
+
+                        return ret;
+                }
+
+                r = cg_migrate_recursive(cfrom, p, cto, pto, ignore_self, rem);
+                if (r != 0 && ret >= 0)
+                        ret = r;
+        }
+
+        if (r < 0 && ret >= 0)
+                ret = r;
+
+        if (rem) {
+                r = cg_rmdir(cfrom, pfrom, true);
+                if (r < 0 && ret >= 0 && r != -ENOENT && r != -EBUSY)
+                        return r;
+        }
+
+        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 (controller) {
+                if (path && suffix)
+                        t = strjoin("/sys/fs/cgroup/", controller, "/", path, "/", suffix, NULL);
+                else if (path)
+                        t = strjoin("/sys/fs/cgroup/", controller, "/", path, NULL);
+                else if (suffix)
+                        t = strjoin("/sys/fs/cgroup/", controller, "/", suffix, NULL);
+                else
+                        t = strappend("/sys/fs/cgroup/", controller);
+        } else {
+                if (path && suffix)
+                        t = strjoin(path, "/", suffix, NULL);
+                else if (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 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);
+}
+
+static int check_hierarchy(const char *p) {
+        char *cc;
+
+        assert(p);
+
+        /* Check if this controller actually really exists */
+        cc = alloca(sizeof("/sys/fs/cgroup/") + strlen(p));
+        strcpy(stpcpy(cc, "/sys/fs/cgroup/"), p);
+        if (access(cc, F_OK) < 0)
+                return -errno;
+
+        return 0;
+}
+
+int cg_get_path_and_check(const char *controller, const char *path, const char *suffix, char **fs) {
+        const char *p;
+        int r;
+
+        assert(fs);
+
+        if (!cg_controller_is_valid(controller, true))
+                return -EINVAL;
+
+        /* Normalize the controller syntax */
+        p = normalize_controller(controller);
+
+        /* Check if this controller actually really exists */
+        r = check_hierarchy(p);
+        if (r < 0)
+                return r;
+
+        return join_path(p, path, suffix, fs);
+}
+
+static int trim_cb(const char *path, const struct stat *sb, int typeflag, struct FTW *ftwbuf) {
+        char *p;
+        bool is_sticky;
+
+        if (typeflag != FTW_DP)
+                return 0;
+
+        if (ftwbuf->level < 1)
+                return 0;
+
+        p = strappend(path, "/tasks");
+        if (!p) {
+                errno = ENOMEM;
+                return 1;
+        }
+
+        is_sticky = file_is_priv_sticky(p) > 0;
+        free(p);
+
+        if (is_sticky)
+                return 0;
+
+        rmdir(path);
+        return 0;
+}
+
+int cg_trim(const char *controller, const char *path, bool delete_root) {
+        _cleanup_free_ char *fs = NULL;
+        int r = 0;
+
+        assert(path);
+
+        r = cg_get_path(controller, path, NULL, &fs);
+        if (r < 0)
+                return r;
+
+        errno = 0;
+        if (nftw(fs, trim_cb, 64, FTW_DEPTH|FTW_MOUNT|FTW_PHYS) != 0)
+                r = errno ? -errno : -EIO;
+
+        if (delete_root) {
+                bool is_sticky;
+                char *p;
+
+                p = strappend(fs, "/tasks");
+                if (!p)
+                        return -ENOMEM;
+
+                is_sticky = file_is_priv_sticky(p) > 0;
+                free(p);
+
+                if (!is_sticky)
+                        if (rmdir(fs) < 0 && errno != ENOENT && r == 0)
+                                return -errno;
+        }
+
+        return r;
+}
+
+int cg_delete(const char *controller, const char *path) {
+        _cleanup_free_ char *parent = NULL;
+        int r;
+
+        assert(path);
+
+        r = path_get_parent(path, &parent);
+        if (r < 0)
+                return r;
+
+        r = cg_migrate_recursive(controller, path, controller, parent, false, true);
+        return r == -ENOENT ? 0 : r;
+}
+
+int cg_attach(const char *controller, const char *path, pid_t pid) {
+        _cleanup_free_ char *fs = NULL;
+        char c[DECIMAL_STR_MAX(pid_t) + 2];
+        int r;
+
+        assert(path);
+        assert(pid >= 0);
+
+        r = cg_get_path_and_check(controller, path, "tasks", &fs);
+        if (r < 0)
+                return r;
+
+        if (pid == 0)
+                pid = getpid();
+
+        snprintf(c, sizeof(c), "%lu\n", (unsigned long) pid);
+
+        return write_string_file(fs, c);
+}
+
+int cg_set_group_access(
+                const char *controller,
+                const char *path,
+                mode_t mode,
+                uid_t uid,
+                gid_t gid) {
+
+        _cleanup_free_ char *fs = NULL;
+        int r;
+
+        assert(path);
+
+        if (mode != (mode_t) -1)
+                mode &= 0777;
+
+        r = cg_get_path(controller, path, NULL, &fs);
+        if (r < 0)
+                return r;
+
+        return chmod_and_chown(fs, mode, uid, gid);
+}
+
+int cg_set_task_access(
+                const char *controller,
+                const char *path,
+                mode_t mode,
+                uid_t uid,
+                gid_t gid,
+                int sticky) {
+
+        _cleanup_free_ char *fs = NULL, *procs = NULL;
+        int r;
+
+        assert(path);
+
+        if (mode == (mode_t) -1 && uid == (uid_t) -1 && gid == (gid_t) -1 && sticky < 0)
+                return 0;
+
+        if (mode != (mode_t) -1)
+                mode &= 0666;
+
+        r = cg_get_path(controller, path, "tasks", &fs);
+        if (r < 0)
+                return r;
+
+        if (sticky >= 0 && mode != (mode_t) -1)
+                /* Both mode and sticky param are passed */
+                mode |= (sticky ? S_ISVTX : 0);
+        else if ((sticky >= 0 && mode == (mode_t) -1) ||
+                 (mode != (mode_t) -1 && sticky < 0)) {
+                struct stat st;
+
+                /* Only one param is passed, hence read the current
+                 * mode from the file itself */
+
+                r = lstat(fs, &st);
+                if (r < 0)
+                        return -errno;
+
+                if (mode == (mode_t) -1)
+                        /* No mode set, we just shall set the sticky bit */
+                        mode = (st.st_mode & ~S_ISVTX) | (sticky ? S_ISVTX : 0);
+                else
+                        /* Only mode set, leave sticky bit untouched */
+                        mode = (st.st_mode & ~0777) | mode;
+        }
+
+        r = chmod_and_chown(fs, mode, uid, gid);
+        if (r < 0)
+                return r;
+
+        /* Always keep values for "cgroup.procs" in sync with "tasks" */
+        r = cg_get_path(controller, path, "cgroup.procs", &procs);
+        if (r < 0)
+                return r;
+
+        return chmod_and_chown(procs, mode, uid, gid);
+}
+
+int cg_pid_get_path(const char *controller, pid_t pid, char **path) {
+        _cleanup_fclose_ FILE *f = NULL;
+        char line[LINE_MAX];
+        const char *fs;
+        size_t cs;
+
+        assert(path);
+        assert(pid >= 0);
+
+        if (controller) {
+                if (!cg_controller_is_valid(controller, true))
+                        return -EINVAL;
+
+                controller = normalize_controller(controller);
+        } else
+                controller = SYSTEMD_CGROUP_CONTROLLER;
+
+        if (pid == 0)
+                fs = "/proc/self/cgroup";
+        else
+                fs = procfs_file_alloca(pid, "cgroup");
+
+        f = fopen(fs, "re");
+        if (!f)
+                return errno == ENOENT ? -ESRCH : -errno;
+
+        cs = strlen(controller);
+
+        FOREACH_LINE(line, f, return -errno) {
+                char *l, *p, *w, *e;
+                size_t k;
+                char *state;
+                bool found = false;
+
+                truncate_nl(line);
+
+                l = strchr(line, ':');
+                if (!l)
+                        continue;
+
+                l++;
+                e = strchr(l, ':');
+                if (!e)
+                        continue;
+
+                *e = 0;
+
+                FOREACH_WORD_SEPARATOR(w, k, l, ",", state) {
+
+                        if (k == cs && memcmp(w, controller, cs) == 0) {
+                                found = true;
+                                break;
+                        }
+
+                        if (k == 5 + cs &&
+                            memcmp(w, "name=", 5) == 0 &&
+                            memcmp(w+5, controller, cs) == 0) {
+                                found = true;
+                                break;
+                        }
+                }
+
+                if (!found)
+                        continue;
+
+                p = strdup(e + 1);
+                if (!p)
+                        return -ENOMEM;
+
+                *path = p;
+                return 0;
+        }
+
+        return -ENOENT;
+}
+
+int cg_install_release_agent(const char *controller, const char *agent) {
+        _cleanup_free_ char *fs = NULL, *contents = NULL;
+        char *sc;
+        int r;
+
+        assert(agent);
+
+        r = cg_get_path(controller, NULL, "release_agent", &fs);
+        if (r < 0)
+                return r;
+
+        r = read_one_line_file(fs, &contents);
+        if (r < 0)
+                return r;
+
+        sc = strstrip(contents);
+        if (sc[0] == 0) {
+                r = write_string_file(fs, agent);
+                if (r < 0)
+                        return r;
+        } else if (!streq(sc, agent))
+                return -EEXIST;
+
+        free(fs);
+        fs = NULL;
+        r = cg_get_path(controller, NULL, "notify_on_release", &fs);
+        if (r < 0)
+                return r;
+
+        free(contents);
+        contents = NULL;
+        r = read_one_line_file(fs, &contents);
+        if (r < 0)
+                return r;
+
+        sc = strstrip(contents);
+        if (streq(sc, "0")) {
+                r = write_string_file(fs, "1");
+                if (r < 0)
+                        return r;
+
+                return 1;
+        }
+
+        if (!streq(sc, "1"))
+                return -EIO;
+
+        return 0;
+}
+
+int cg_is_empty(const char *controller, const char *path, bool ignore_self) {
+        _cleanup_fclose_ FILE *f = NULL;
+        pid_t pid = 0, self_pid;
+        bool found = false;
+        int r;
+
+        assert(path);
+
+        r = cg_enumerate_tasks(controller, path, &f);
+        if (r < 0)
+                return r == -ENOENT ? 1 : r;
+
+        self_pid = getpid();
+
+        while ((r = cg_read_pid(f, &pid)) > 0) {
+
+                if (ignore_self && pid == self_pid)
+                        continue;
+
+                found = true;
+                break;
+        }
+
+        if (r < 0)
+                return r;
+
+        return !found;
+}
+
+int cg_is_empty_by_spec(const char *spec, bool ignore_self) {
+        _cleanup_free_ char *controller = NULL, *path = NULL;
+        int r;
+
+        assert(spec);
+
+        r = cg_split_spec(spec, &controller, &path);
+        if (r < 0)
+                return r;
+
+        return cg_is_empty(controller, path, ignore_self);
+}
+
+int cg_is_empty_recursive(const char *controller, const char *path, bool ignore_self) {
+        _cleanup_closedir_ DIR *d = NULL;
+        char *fn;
+        int r;
+
+        assert(path);
+
+        r = cg_is_empty(controller, path, ignore_self);
+        if (r <= 0)
+                return r;
+
+        r = cg_enumerate_subgroups(controller, path, &d);
+        if (r < 0)
+                return r == -ENOENT ? 1 : r;
+
+        while ((r = cg_read_subgroup(d, &fn)) > 0) {
+                _cleanup_free_ char *p = NULL;
+
+                p = strjoin(path, "/", fn, NULL);
+                free(fn);
+                if (!p)
+                        return -ENOMEM;
+
+                r = cg_is_empty_recursive(controller, p, ignore_self);
+                if (r <= 0)
+                        return r;
+        }
+
+        if (r < 0)
+                return r;
+
+        return 1;
+}
+
+int cg_split_spec(const char *spec, char **controller, char **path) {
+        const char *e;
+        char *t = NULL, *u = NULL;
+        _cleanup_free_ char *v = NULL;
+
+        assert(spec);
+
+        if (*spec == '/') {
+                if (!path_is_safe(spec))
+                        return -EINVAL;
+
+                if (path) {
+                        t = strdup(spec);
+                        if (!t)
+                                return -ENOMEM;
+
+                        path_kill_slashes(t);
+                        *path = t;
+                }
+
+                if (controller)
+                        *controller = NULL;
+
+                return 0;
+        }
+
+        e = strchr(spec, ':');
+        if (!e) {
+                if (!cg_controller_is_valid(spec, true))
+                        return -EINVAL;
+
+                if (controller) {
+                        t = strdup(normalize_controller(spec));
+                        if (!t)
+                                return -ENOMEM;
+
+                        *controller = t;
+                }
+
+                if (path)
+                        *path = NULL;
+
+                return 0;
+        }
+
+        v = strndup(spec, e-spec);
+        if (!v)
+                return -ENOMEM;
+        t = strdup(normalize_controller(v));
+        if (!t)
+                return -ENOMEM;
+        if (!cg_controller_is_valid(t, true)) {
+                free(t);
+                return -EINVAL;
+        }
+
+        u = strdup(e+1);
+        if (!u) {
+                free(t);
+                return -ENOMEM;
+        }
+        if (!path_is_safe(u) ||
+            !path_is_absolute(u)) {
+                free(t);
+                free(u);
+                return -EINVAL;
+        }
+
+        path_kill_slashes(u);
+
+        if (controller)
+                *controller = t;
+        else
+                free(t);
+
+        if (path)
+                *path = u;
+        else
+                free(u);
+
+        return 0;
+}
+
+int cg_join_spec(const char *controller, const char *path, char **spec) {
+        char *s;
+
+        assert(path);
+
+        if (!controller)
+                controller = "systemd";
+        else {
+                if (!cg_controller_is_valid(controller, true))
+                        return -EINVAL;
+
+                controller = normalize_controller(controller);
+        }
+
+        if (!path_is_absolute(path))
+                return -EINVAL;
+
+        s = strjoin(controller, ":", path, NULL);
+        if (!s)
+                return -ENOMEM;
+
+        path_kill_slashes(s + strlen(controller) + 1);
+
+        *spec = s;
+        return 0;
+}
+
+int cg_mangle_path(const char *path, char **result) {
+        _cleanup_free_ char *c = NULL, *p = NULL;
+        char *t;
+        int r;
+
+        assert(path);
+        assert(result);
+
+        /* First check if it already is a filesystem path */
+        if (path_startswith(path, "/sys/fs/cgroup")) {
+
+                t = strdup(path);
+                if (!t)
+                        return -ENOMEM;
+
+                path_kill_slashes(t);
+                *result = t;
+                return 0;
+        }
+
+        /* Otherwise treat it as cg spec */
+        r = cg_split_spec(path, &c, &p);
+        if (r < 0)
+                return r;
+
+        return cg_get_path(c ? c : SYSTEMD_CGROUP_CONTROLLER, p ? p : "/", NULL, result);
+}
+
+int cg_get_system_path(char **path) {
+        char *p;
+        int r;
+
+        assert(path);
+
+        r = cg_pid_get_path(SYSTEMD_CGROUP_CONTROLLER, 1, &p);
+        if (r < 0) {
+                p = strdup("/system");
+                if (!p)
+                        return -ENOMEM;
+        }
+
+        if (endswith(p, "/system"))
+                *path = p;
+        else {
+                char *q;
+
+                q = strappend(p, "/system");
+                free(p);
+                if (!q)
+                        return -ENOMEM;
+
+                *path = q;
+        }
+
+        return 0;
+}
+
+int cg_get_root_path(char **path) {
+        char *root, *e;
+        int r;
+
+        assert(path);
+
+        r = cg_pid_get_path(SYSTEMD_CGROUP_CONTROLLER, 1, &root);
+        if (r < 0)
+                return r;
+
+        e = endswith(root, "/system");
+        if (e == root)
+                e[1] = 0;
+        else if (e)
+                *e = 0;
+
+        *path = root;
+        return 0;
+}
+
+int cg_get_user_path(char **path) {
+        _cleanup_free_ char *root = NULL;
+        char *p;
+
+        assert(path);
+
+        /* Figure out the place to put user cgroups below. We use the
+         * same as PID 1 has but with the "/system" suffix replaced by
+         * "/user" */
+
+        if (cg_get_root_path(&root) < 0 || streq(root, "/"))
+                p = strdup("/user");
+        else
+                p = strappend(root, "/user");
+
+        if (!p)
+                return -ENOMEM;
+
+        *path = p;
+        return 0;
+}
+
+int cg_get_machine_path(const char *machine, char **path) {
+        _cleanup_free_ char *root = NULL, *escaped = NULL;
+        char *p;
+
+        assert(path);
+
+        if (machine) {
+                const char *name = strappenda(machine, ".nspawn");
+
+                escaped = cg_escape(name);
+                if (!escaped)
+                        return -ENOMEM;
+        }
+
+        p = strjoin(cg_get_root_path(&root) >= 0 && !streq(root, "/") ? root : "",
+                    "/machine", machine ? "/" : "", machine ? escaped : "", NULL);
+        if (!p)
+                return -ENOMEM;
+
+        *path = p;
+        return 0;
+}
+
+char **cg_shorten_controllers(char **controllers) {
+        char **f, **t;
+
+        if (!controllers)
+                return controllers;
+
+        for (f = controllers, t = controllers; *f; f++) {
+                const char *p;
+                int r;
+
+                p = normalize_controller(*f);
+
+                if (streq(p, "systemd")) {
+                        free(*f);
+                        continue;
+                }
+
+                if (!cg_controller_is_valid(p, true)) {
+                        log_warning("Controller %s is not valid, removing from controllers list.", p);
+                        free(*f);
+                        continue;
+                }
+
+                r = check_hierarchy(p);
+                if (r < 0) {
+                        log_debug("Controller %s is not available, removing from controllers list.", p);
+                        free(*f);
+                        continue;
+                }
+
+                *(t++) = *f;
+        }
+
+        *t = NULL;
+        return strv_uniq(controllers);
+}
+
+int cg_pid_get_path_shifted(pid_t pid, char **root, char **cgroup) {
+        _cleanup_free_ char *cg_root = NULL;
+        char *cg_process, *p;
+        int r;
+
+        r = cg_get_root_path(&cg_root);
+        if (r < 0)
+                return r;
+
+        r = cg_pid_get_path(SYSTEMD_CGROUP_CONTROLLER, pid, &cg_process);
+        if (r < 0)
+                return r;
+
+        p = path_startswith(cg_process, cg_root);
+        if (p)
+                p--;
+        else
+                p = cg_process;
+
+        if (cgroup) {
+                char* c;
+
+                c = strdup(p);
+                if (!c) {
+                        free(cg_process);
+                        return -ENOMEM;
+                }
+
+                *cgroup = c;
+        }
+
+        if (root) {
+                cg_process[p-cg_process] = 0;
+                *root = cg_process;
+        } else
+                free(cg_process);
+
+        return 0;
+}
+
+int cg_path_decode_unit(const char *cgroup, char **unit){
+        char *p, *e, *c, *s, *k;
+
+        assert(cgroup);
+        assert(unit);
+
+        e = strchrnul(cgroup, '/');
+        c = strndupa(cgroup, e - cgroup);
+        c = cg_unescape(c);
+
+        /* Could this be a valid unit name? */
+        if (!unit_name_is_valid(c, true))
+                return -EINVAL;
+
+        if (!unit_name_is_template(c))
+                s = strdup(c);
+        else {
+                if (*e != '/')
+                        return -EINVAL;
+
+                e += strspn(e, "/");
+
+                p = strchrnul(e, '/');
+                k = strndupa(e, p - e);
+                k = cg_unescape(k);
+
+                if (!unit_name_is_valid(k, false))
+                        return -EINVAL;
+
+                s = strdup(k);
+        }
+
+        if (!s)
+                return -ENOMEM;
+
+        *unit = s;
+        return 0;
+}
+
+int cg_path_get_unit(const char *path, char **unit) {
+        const char *e;
+
+        assert(path);
+        assert(unit);
+
+        e = path_startswith(path, "/system/");
+        if (!e)
+                return -ENOENT;
+
+        return cg_path_decode_unit(e, unit);
+}
+
+int cg_pid_get_unit(pid_t pid, char **unit) {
+        _cleanup_free_ char *cgroup = NULL;
+        int r;
+
+        assert(unit);
+
+        r = cg_pid_get_path_shifted(pid, NULL, &cgroup);
+        if (r < 0)
+                return r;
+
+        return cg_path_get_unit(cgroup, unit);
+}
+
+_pure_ static const char *skip_label(const char *e) {
+        assert(e);
+
+        e = strchr(e, '/');
+        if (!e)
+                return NULL;
+
+        e += strspn(e, "/");
+        return e;
+}
+
+int cg_path_get_user_unit(const char *path, char **unit) {
+        const char *e;
+
+        assert(path);
+        assert(unit);
+
+        /* We always have to parse the path from the beginning as unit
+         * cgroups might have arbitrary child cgroups and we shouldn't get
+         * confused by those */
+
+        e = path_startswith(path, "/user/");
+        if (!e)
+                return -ENOENT;
+
+        /* Skip the user name */
+        e = skip_label(e);
+        if (!e)
+                return -ENOENT;
+
+        /* Skip the session ID */
+        e = skip_label(e);
+        if (!e)
+                return -ENOENT;
+
+        /* Skip the systemd cgroup */
+        e = skip_label(e);
+        if (!e)
+                return -ENOENT;
+
+        return cg_path_decode_unit(e, unit);
+}
+
+int cg_pid_get_user_unit(pid_t pid, char **unit) {
+        _cleanup_free_ char *cgroup = NULL;
+        int r;
+
+        assert(unit);
+
+        r = cg_pid_get_path_shifted(pid, NULL, &cgroup);
+        if (r < 0)
+                return r;
+
+        return cg_path_get_user_unit(cgroup, unit);
+}
+
+int cg_path_get_machine_name(const char *path, char **machine) {
+        const char *e, *n;
+        char *s, *r;
+
+        assert(path);
+        assert(machine);
+
+        e = path_startswith(path, "/machine/");
+        if (!e)
+                return -ENOENT;
+
+        n = strchrnul(e, '/');
+        if (e == n)
+                return -ENOENT;
+
+        s = strndupa(e, n - e);
+
+        r = strdup(cg_unescape(s));
+        if (!r)
+                return -ENOMEM;
+
+        *machine = r;
+        return 0;
+}
+
+int cg_pid_get_machine_name(pid_t pid, char **machine) {
+        _cleanup_free_ char *cgroup = NULL;
+        int r;
+
+        assert(machine);
+
+        r = cg_pid_get_path_shifted(pid, NULL, &cgroup);
+        if (r < 0)
+                return r;
+
+        return cg_path_get_machine_name(cgroup, machine);
+}
+
+int cg_path_get_session(const char *path, char **session) {
+        const char *e, *n;
+        char *s;
+
+        assert(path);
+        assert(session);
+
+        e = path_startswith(path, "/user/");
+        if (!e)
+                return -ENOENT;
+
+        /* Skip the user name */
+        e = skip_label(e);
+        if (!e)
+                return -ENOENT;
+
+        n = strchrnul(e, '/');
+        if (n - e < 8)
+                return -ENOENT;
+        if (memcmp(n - 8, ".session", 8) != 0)
+                return -ENOENT;
+
+        s = strndup(e, n - e - 8);
+        if (!s)
+                return -ENOMEM;
+
+        *session = s;
+        return 0;
+}
+
+int cg_pid_get_session(pid_t pid, char **session) {
+        _cleanup_free_ char *cgroup = NULL;
+        int r;
+
+        assert(session);
+
+        r = cg_pid_get_path_shifted(pid, NULL, &cgroup);
+        if (r < 0)
+                return r;
+
+        return cg_path_get_session(cgroup, session);
+}
+
+int cg_path_get_owner_uid(const char *path, uid_t *uid) {
+        const char *e, *n;
+        char *s;
+
+        assert(path);
+        assert(uid);
+
+        e = path_startswith(path, "/user/");
+        if (!e)
+                return -ENOENT;
+
+        n = strchrnul(e, '/');
+        if (n - e < 5)
+                return -ENOENT;
+        if (memcmp(n - 5, ".user", 5) != 0)
+                return -ENOENT;
+
+        s = strndupa(e, n - e - 5);
+        if (!s)
+                return -ENOMEM;
+
+        return parse_uid(s, uid);
+}
+
+int cg_pid_get_owner_uid(pid_t pid, uid_t *uid) {
+        _cleanup_free_ char *cgroup = NULL;
+        int r;
+
+        assert(uid);
+
+        r = cg_pid_get_path_shifted(pid, NULL, &cgroup);
+        if (r < 0)
+                return r;
+
+        return cg_path_get_owner_uid(cgroup, uid);
+}
+
+int cg_controller_from_attr(const char *attr, char **controller) {
+        const char *dot;
+        char *c;
+
+        assert(attr);
+        assert(controller);
+
+        if (!filename_is_safe(attr))
+                return -EINVAL;
+
+        dot = strchr(attr, '.');
+        if (!dot) {
+                *controller = NULL;
+                return 0;
+        }
+
+        c = strndup(attr, dot - attr);
+        if (!c)
+                return -ENOMEM;
+
+        if (!cg_controller_is_valid(c, false)) {
+                free(c);
+                return -EINVAL;
+        }
+
+        *controller = c;
+        return 1;
+}
+
+char *cg_escape(const char *p) {
+        bool need_prefix = false;
+
+        /* This implements very minimal escaping for names to be used
+         * as file names in the cgroup tree: any name which might
+         * conflict with a kernel name or is prefixed with '_' is
+         * prefixed with a '_'. That way, when reading cgroup names it
+         * is sufficient to remove a single prefixing underscore if
+         * there is one. */
+
+        /* The return value of this function (unlike cg_unescape())
+         * needs free()! */
+
+        if (p[0] == 0 ||
+            p[0] == '_' ||
+            p[0] == '.' ||
+            streq(p, "notify_on_release") ||
+            streq(p, "release_agent") ||
+            streq(p, "tasks"))
+                need_prefix = true;
+        else {
+                const char *dot;
+
+                dot = strrchr(p, '.');
+                if (dot) {
+
+                        if (dot - p == 6 && memcmp(p, "cgroup", 6) == 0)
+                                need_prefix = true;
+                        else {
+                                char *n;
+
+                                n = strndupa(p, dot - p);
+
+                                if (check_hierarchy(n) >= 0)
+                                        need_prefix = true;
+                        }
+                }
+        }
+
+        if (need_prefix)
+                return strappend("_", p);
+        else
+                return strdup(p);
+}
+
+char *cg_unescape(const char *p) {
+        assert(p);
+
+        /* The return value of this function (unlike cg_escape())
+         * doesn't need free()! */
+
+        if (p[0] == '_')
+                return (char*) p+1;
+
+        return (char*) p;
+}
+
+#define CONTROLLER_VALID                        \
+        "0123456789"                            \
+        "abcdefghijklmnopqrstuvwxyz"            \
+        "ABCDEFGHIJKLMNOPQRSTUVWXYZ"            \
+        "_"
+
+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;
+}