Merge pull request #160 from kaysievers/libsplit

build-sys: split internal basic/ library from shared/

1 files changed, 1917 insertions, 0 deletions

diff --git a/src/basic/cgroup-util.c b/src/basic/cgroup-util.c
new file mode 100644
index 0000000000..66857f118f
--- /dev/null
+++ b/src/basic/cgroup-util.c
@@ -0,0 +1,1917 @@
+/*-*- 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 "set.h"
+#include "macro.h"
+#include "util.h"
+#include "formats-util.h"
+#include "process-util.h"
+#include "path-util.h"
+#include "unit-name.h"
+#include "fileio.h"
+#include "special.h"
+#include "mkdir.h"
+#include "login-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_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) {
+        _cleanup_free_ char *p = NULL;
+        int r;
+
+        r = cg_get_path(controller, path, NULL, &p);
+        if (r < 0)
+                return r;
+
+        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(NULL);
+                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 (sigcont && sig != SIGKILL)
+                                        kill(pid, SIGCONT);
+
+                                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;
+                }
+
+                /* 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(NULL);
+                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);
+                if (r < 0 && ret >= 0 && r != -ENOENT && r != -EBUSY)
+                        return r;
+        }
+
+        return ret;
+}
+
+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(NULL);
+        if (!s)
+                return -ENOMEM;
+
+        my_pid = getpid();
+
+        do {
+                _cleanup_fclose_ FILE *f = NULL;
+                pid_t pid = 0;
+                done = true;
+
+                r = cg_enumerate_processes(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);
+                if (r < 0 && ret >= 0 && r != -ENOENT && r != -EBUSY)
+                        return r;
+        }
+
+        return ret;
+}
+
+int cg_migrate_recursive_fallback(
+                const char *cfrom,
+                const char *pfrom,
+                const char *cto,
+                const char *pto,
+                bool ignore_self,
+                bool rem) {
+
+        int r;
+
+        assert(cfrom);
+        assert(pfrom);
+        assert(cto);
+        assert(pto);
+
+        r = cg_migrate_recursive(cfrom, pfrom, cto, pto, ignore_self, rem);
+        if (r < 0) {
+                char prefix[strlen(pto) + 1];
+
+                /* This didn't work? Then let's try all prefixes of the destination */
+
+                PATH_FOREACH_PREFIX(prefix, pto) {
+                        r = cg_migrate_recursive(cfrom, pfrom, cto, prefix, ignore_self, rem);
+                        if (r >= 0)
+                                break;
+                }
+        }
+
+        return 0;
+}
+
+static const char *normalize_controller(const char *controller) {
+
+        assert(controller);
+
+        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;
+
+        *fs = path_kill_slashes(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))
+                return -EINVAL;
+
+        if (_unlikely_(!good)) {
+                int r;
+
+                r = path_is_mount_point("/sys/fs/cgroup", 0);
+                if (r < 0)
+                        return r;
+                if (r == 0)
+                        return -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) {
+        const char *cc;
+
+        assert(p);
+
+        if (!filename_is_valid(p))
+                return 0;
+
+        /* Check if this controller actually really exists */
+        cc = strjoina("/sys/fs/cgroup/", p);
+        if (laccess(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))
+                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) {
+        assert(path);
+        assert(sb);
+        assert(ftwbuf);
+
+        if (typeflag != FTW_DP)
+                return 0;
+
+        if (ftwbuf->level < 1)
+                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) {
+                if (rmdir(fs) < 0 && errno != ENOENT)
+                        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_create(const char *controller, const char *path) {
+        _cleanup_free_ char *fs = NULL;
+        int r;
+
+        r = cg_get_path_and_check(controller, path, NULL, &fs);
+        if (r < 0)
+                return r;
+
+        r = mkdir_parents(fs, 0755);
+        if (r < 0)
+                return r;
+
+        if (mkdir(fs, 0755) < 0) {
+
+                if (errno == EEXIST)
+                        return 0;
+
+                return -errno;
+        }
+
+        return 1;
+}
+
+int cg_create_and_attach(const char *controller, const char *path, pid_t pid) {
+        int r, q;
+
+        assert(pid >= 0);
+
+        r = cg_create(controller, path);
+        if (r < 0)
+                return r;
+
+        q = cg_attach(controller, path, pid);
+        if (q < 0)
+                return q;
+
+        /* This does not remove the cgroup on failure */
+        return 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, "cgroup.procs", &fs);
+        if (r < 0)
+                return r;
+
+        if (pid == 0)
+                pid = getpid();
+
+        snprintf(c, sizeof(c), PID_FMT"\n", pid);
+
+        return write_string_file_no_create(fs, c);
+}
+
+int cg_attach_fallback(const char *controller, const char *path, pid_t pid) {
+        int r;
+
+        assert(controller);
+        assert(path);
+        assert(pid >= 0);
+
+        r = cg_attach(controller, path, pid);
+        if (r < 0) {
+                char prefix[strlen(path) + 1];
+
+                /* This didn't work? Then let's try all prefixes of
+                 * the destination */
+
+                PATH_FOREACH_PREFIX(prefix, path) {
+                        r = cg_attach(controller, prefix, pid);
+                        if (r >= 0)
+                                break;
+                }
+        }
+
+        return 0;
+}
+
+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_INVALID)
+                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) {
+
+        _cleanup_free_ char *fs = NULL, *procs = NULL;
+        int r;
+
+        assert(path);
+
+        if (mode == MODE_INVALID && uid == UID_INVALID && gid == GID_INVALID)
+                return 0;
+
+        if (mode != MODE_INVALID)
+                mode &= 0666;
+
+        r = cg_get_path(controller, path, "cgroup.procs", &fs);
+        if (r < 0)
+                return r;
+
+        r = chmod_and_chown(fs, mode, uid, gid);
+        if (r < 0)
+                return r;
+
+        /* Compatibility, Always keep values for "tasks" in sync with
+         * "cgroup.procs" */
+        r = cg_get_path(controller, path, "tasks", &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))
+                        return -EINVAL;
+
+                controller = normalize_controller(controller);
+        } else
+                controller = SYSTEMD_CGROUP_CONTROLLER;
+
+        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, *e;
+                size_t k;
+                const char *word, *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(word, k, l, ",", state) {
+
+                        if (k == cs && memcmp(word, controller, cs) == 0) {
+                                found = true;
+                                break;
+                        }
+
+                        if (k == 5 + cs &&
+                            memcmp(word, "name=", 5) == 0 &&
+                            memcmp(word+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_no_create(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_no_create(fs, "1");
+                if (r < 0)
+                        return r;
+
+                return 1;
+        }
+
+        if (!streq(sc, "1"))
+                return -EIO;
+
+        return 0;
+}
+
+int cg_uninstall_release_agent(const char *controller) {
+        _cleanup_free_ char *fs = NULL;
+        int r;
+
+        r = cg_get_path(controller, NULL, "notify_on_release", &fs);
+        if (r < 0)
+                return r;
+
+        r = write_string_file_no_create(fs, "0");
+        if (r < 0)
+                return r;
+
+        free(fs);
+        fs = NULL;
+
+        r = cg_get_path(controller, NULL, "release_agent", &fs);
+        if (r < 0)
+                return r;
+
+        r = write_string_file_no_create(fs, "");
+        if (r < 0)
+                return r;
+
+        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_processes(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_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 = path_kill_slashes(t);
+                }
+
+                if (controller)
+                        *controller = NULL;
+
+                return 0;
+        }
+
+        e = strchr(spec, ':');
+        if (!e) {
+                if (!cg_controller_is_valid(spec))
+                        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)) {
+                free(t);
+                return -EINVAL;
+        }
+
+        if (streq(e+1, "")) {
+                u = strdup("/");
+                if (!u) {
+                        free(t);
+                        return -ENOMEM;
+                }
+        } else {
+                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_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;
+
+                *result = path_kill_slashes(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_root_path(char **path) {
+        char *p, *e;
+        int r;
+
+        assert(path);
+
+        r = cg_pid_get_path(SYSTEMD_CGROUP_CONTROLLER, 1, &p);
+        if (r < 0)
+                return r;
+
+        e = endswith(p, "/" SPECIAL_SYSTEM_SLICE);
+        if (e)
+                *e = 0;
+
+        *path = p;
+        return 0;
+}
+
+int cg_shift_path(const char *cgroup, const char *root, const char **shifted) {
+        _cleanup_free_ char *rt = NULL;
+        char *p;
+        int r;
+
+        assert(cgroup);
+        assert(shifted);
+
+        if (!root) {
+                /* If the root was specified let's use that, otherwise
+                 * let's determine it from PID 1 */
+
+                r = cg_get_root_path(&rt);
+                if (r < 0)
+                        return r;
+
+                root = rt;
+        }
+
+        p = path_startswith(cgroup, root);
+        if (p)
+                *shifted = p - 1;
+        else
+                *shifted = cgroup;
+
+        return 0;
+}
+
+int cg_pid_get_path_shifted(pid_t pid, const char *root, char **cgroup) {
+        _cleanup_free_ char *raw = NULL;
+        const char *c;
+        int r;
+
+        assert(pid >= 0);
+        assert(cgroup);
+
+        r = cg_pid_get_path(SYSTEMD_CGROUP_CONTROLLER, pid, &raw);
+        if (r < 0)
+                return r;
+
+        r = cg_shift_path(raw, root, &c);
+        if (r < 0)
+                return r;
+
+        if (c == raw) {
+                *cgroup = raw;
+                raw = NULL;
+        } else {
+                char *n;
+
+                n = strdup(c);
+                if (!n)
+                        return -ENOMEM;
+
+                *cgroup = n;
+        }
+
+        return 0;
+}
+
+int cg_path_decode_unit(const char *cgroup, char **unit){
+        char *c, *s;
+        size_t n;
+
+        assert(cgroup);
+        assert(unit);
+
+        n = strcspn(cgroup, "/");
+        if (n < 3)
+                return -ENXIO;
+
+        c = strndupa(cgroup, n);
+        c = cg_unescape(c);
+
+        if (!unit_name_is_valid(c, UNIT_NAME_PLAIN|UNIT_NAME_INSTANCE))
+                return -ENXIO;
+
+        s = strdup(c);
+        if (!s)
+                return -ENOMEM;
+
+        *unit = s;
+        return 0;
+}
+
+static bool valid_slice_name(const char *p, size_t n) {
+
+        if (!p)
+                return false;
+
+        if (n < strlen("x.slice"))
+                return false;
+
+        if (memcmp(p + n - 6, ".slice", 6) == 0) {
+                char buf[n+1], *c;
+
+                memcpy(buf, p, n);
+                buf[n] = 0;
+
+                c = cg_unescape(buf);
+
+                return unit_name_is_valid(c, UNIT_NAME_PLAIN);
+        }
+
+        return false;
+}
+
+static const char *skip_slices(const char *p) {
+        assert(p);
+
+        /* Skips over all slice assignments */
+
+        for (;;) {
+                size_t n;
+
+                p += strspn(p, "/");
+
+                n = strcspn(p, "/");
+                if (!valid_slice_name(p, n))
+                        return p;
+
+                p += n;
+        }
+}
+
+int cg_path_get_unit(const char *path, char **ret) {
+        const char *e;
+        char *unit;
+        int r;
+
+        assert(path);
+        assert(ret);
+
+        e = skip_slices(path);
+
+        r = cg_path_decode_unit(e, &unit);
+        if (r < 0)
+                return r;
+
+        /* We skipped over the slices, don't accept any now */
+        if (endswith(unit, ".slice")) {
+                free(unit);
+                return -ENXIO;
+        }
+
+        *ret = unit;
+        return 0;
+}
+
+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);
+}
+
+/**
+ * Skip session-*.scope, but require it to be there.
+ */
+static const char *skip_session(const char *p) {
+        size_t n;
+
+        if (isempty(p))
+                return NULL;
+
+        p += strspn(p, "/");
+
+        n = strcspn(p, "/");
+        if (n < strlen("session-x.scope"))
+                return NULL;
+
+        if (memcmp(p, "session-", 8) == 0 && memcmp(p + n - 6, ".scope", 6) == 0) {
+                char buf[n - 8 - 6 + 1];
+
+                memcpy(buf, p + 8, n - 8 - 6);
+                buf[n - 8 - 6] = 0;
+
+                /* Note that session scopes never need unescaping,
+                 * since they cannot conflict with the kernel's own
+                 * names, hence we don't need to call cg_unescape()
+                 * here. */
+
+                if (!session_id_valid(buf))
+                        return false;
+
+                p += n;
+                p += strspn(p, "/");
+                return p;
+        }
+
+        return NULL;
+}
+
+/**
+ * Skip user@*.service, but require it to be there.
+ */
+static const char *skip_user_manager(const char *p) {
+        size_t n;
+
+        if (isempty(p))
+                return NULL;
+
+        p += strspn(p, "/");
+
+        n = strcspn(p, "/");
+        if (n < strlen("user@x.service"))
+                return NULL;
+
+        if (memcmp(p, "user@", 5) == 0 && memcmp(p + n - 8, ".service", 8) == 0) {
+                char buf[n - 5 - 8 + 1];
+
+                memcpy(buf, p + 5, n - 5 - 8);
+                buf[n - 5 - 8] = 0;
+
+                /* Note that user manager services never need unescaping,
+                 * since they cannot conflict with the kernel's own
+                 * names, hence we don't need to call cg_unescape()
+                 * here. */
+
+                if (parse_uid(buf, NULL) < 0)
+                        return NULL;
+
+                p += n;
+                p += strspn(p, "/");
+
+                return p;
+        }
+
+        return NULL;
+}
+
+static const char *skip_user_prefix(const char *path) {
+        const char *e, *t;
+
+        assert(path);
+
+        /* Skip slices, if there are any */
+        e = skip_slices(path);
+
+        /* Skip the user manager, if it's in the path now... */
+        t = skip_user_manager(e);
+        if (t)
+                return t;
+
+        /* Alternatively skip the user session if it is in the path... */
+        return skip_session(e);
+}
+
+int cg_path_get_user_unit(const char *path, char **ret) {
+        const char *t;
+
+        assert(path);
+        assert(ret);
+
+        t = skip_user_prefix(path);
+        if (!t)
+                return -ENXIO;
+
+        /* And from here on it looks pretty much the same as for a
+         * system unit, hence let's use the same parser from here
+         * on. */
+        return cg_path_get_unit(t, ret);
+}
+
+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) {
+        _cleanup_free_ char *u = NULL, *sl = NULL;
+        int r;
+
+        r = cg_path_get_unit(path, &u);
+        if (r < 0)
+                return r;
+
+        sl = strjoin("/run/systemd/machines/unit:", u, NULL);
+        if (!sl)
+                return -ENOMEM;
+
+        return readlink_malloc(sl, machine);
+}
+
+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) {
+        _cleanup_free_ char *unit = NULL;
+        char *start, *end;
+        int r;
+
+        assert(path);
+
+        r = cg_path_get_unit(path, &unit);
+        if (r < 0)
+                return r;
+
+        start = startswith(unit, "session-");
+        if (!start)
+                return -ENXIO;
+        end = endswith(start, ".scope");
+        if (!end)
+                return -ENXIO;
+
+        *end = 0;
+        if (!session_id_valid(start))
+                return -ENXIO;
+
+        if (session) {
+                char *rr;
+
+                rr = strdup(start);
+                if (!rr)
+                        return -ENOMEM;
+
+                *session = rr;
+        }
+
+        return 0;
+}
+
+int cg_pid_get_session(pid_t pid, char **session) {
+        _cleanup_free_ char *cgroup = NULL;
+        int r;
+
+        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) {
+        _cleanup_free_ char *slice = NULL;
+        char *start, *end;
+        int r;
+
+        assert(path);
+
+        r = cg_path_get_slice(path, &slice);
+        if (r < 0)
+                return r;
+
+        start = startswith(slice, "user-");
+        if (!start)
+                return -ENXIO;
+        end = endswith(start, ".slice");
+        if (!end)
+                return -ENXIO;
+
+        *end = 0;
+        if (parse_uid(start, uid) < 0)
+                return -ENXIO;
+
+        return 0;
+}
+
+int cg_pid_get_owner_uid(pid_t pid, uid_t *uid) {
+        _cleanup_free_ char *cgroup = NULL;
+        int r;
+
+        r = cg_pid_get_path_shifted(pid, NULL, &cgroup);
+        if (r < 0)
+                return r;
+
+        return cg_path_get_owner_uid(cgroup, uid);
+}
+
+int cg_path_get_slice(const char *p, char **slice) {
+        const char *e = NULL;
+
+        assert(p);
+        assert(slice);
+
+        /* Finds the right-most slice unit from the beginning, but
+         * stops before we come to the first non-slice unit. */
+
+        for (;;) {
+                size_t n;
+
+                p += strspn(p, "/");
+
+                n = strcspn(p, "/");
+                if (!valid_slice_name(p, n)) {
+
+                        if (!e) {
+                                char *s;
+
+                                s = strdup("-.slice");
+                                if (!s)
+                                        return -ENOMEM;
+
+                                *slice = s;
+                                return 0;
+                        }
+
+                        return cg_path_decode_unit(e, slice);
+                }
+
+                e = p;
+                p += n;
+        }
+}
+
+int cg_pid_get_slice(pid_t pid, char **slice) {
+        _cleanup_free_ char *cgroup = NULL;
+        int r;
+
+        assert(slice);
+
+        r = cg_pid_get_path_shifted(pid, NULL, &cgroup);
+        if (r < 0)
+                return r;
+
+        return cg_path_get_slice(cgroup, slice);
+}
+
+int cg_path_get_user_slice(const char *p, char **slice) {
+        const char *t;
+        assert(p);
+        assert(slice);
+
+        t = skip_user_prefix(p);
+        if (!t)
+                return -ENXIO;
+
+        /* And now it looks pretty much the same as for a system
+         * slice, so let's just use the same parser from here on. */
+        return cg_path_get_slice(t, slice);
+}
+
+int cg_pid_get_user_slice(pid_t pid, char **slice) {
+        _cleanup_free_ char *cgroup = NULL;
+        int r;
+
+        assert(slice);
+
+        r = cg_pid_get_path_shifted(pid, NULL, &cgroup);
+        if (r < 0)
+                return r;
+
+        return cg_path_get_user_slice(cgroup, slice);
+}
+
+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                        \
+        DIGITS LETTERS                          \
+        "_"
+
+bool cg_controller_is_valid(const char *p) {
+        const char *t, *s;
+
+        if (!p)
+                return false;
+
+        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;
+}
+
+int cg_slice_to_path(const char *unit, char **ret) {
+        _cleanup_free_ char *p = NULL, *s = NULL, *e = NULL;
+        const char *dash;
+        int r;
+
+        assert(unit);
+        assert(ret);
+
+        if (streq(unit, "-.slice")) {
+                char *x;
+
+                x = strdup("");
+                if (!x)
+                        return -ENOMEM;
+                *ret = x;
+                return 0;
+        }
+
+        if (!unit_name_is_valid(unit, UNIT_NAME_PLAIN))
+                return -EINVAL;
+
+        if (!endswith(unit, ".slice"))
+                return -EINVAL;
+
+        r = unit_name_to_prefix(unit, &p);
+        if (r < 0)
+                return r;
+
+        dash = strchr(p, '-');
+
+        /* Don't allow initial dashes */
+        if (dash == p)
+                return -EINVAL;
+
+        while (dash) {
+                _cleanup_free_ char *escaped = NULL;
+                char n[dash - p + sizeof(".slice")];
+
+                /* Don't allow trailing or double dashes */
+                if (dash[1] == 0 || dash[1] == '-')
+                        return -EINVAL;
+
+                strcpy(stpncpy(n, p, dash - p), ".slice");
+                if (!unit_name_is_valid(n, UNIT_NAME_PLAIN))
+                        return -EINVAL;
+
+                escaped = cg_escape(n);
+                if (!escaped)
+                        return -ENOMEM;
+
+                if (!strextend(&s, escaped, "/", NULL))
+                        return -ENOMEM;
+
+                dash = strchr(dash+1, '-');
+        }
+
+        e = cg_escape(unit);
+        if (!e)
+                return -ENOMEM;
+
+        if (!strextend(&s, e, NULL))
+                return -ENOMEM;
+
+        *ret = s;
+        s = NULL;
+
+        return 0;
+}
+
+int cg_set_attribute(const char *controller, const char *path, const char *attribute, const char *value) {
+        _cleanup_free_ char *p = NULL;
+        int r;
+
+        r = cg_get_path(controller, path, attribute, &p);
+        if (r < 0)
+                return r;
+
+        return write_string_file_no_create(p, value);
+}
+
+int cg_get_attribute(const char *controller, const char *path, const char *attribute, char **ret) {
+        _cleanup_free_ char *p = NULL;
+        int r;
+
+        r = cg_get_path(controller, path, attribute, &p);
+        if (r < 0)
+                return r;
+
+        return read_one_line_file(p, ret);
+}
+
+static const char mask_names[] =
+        "cpu\0"
+        "cpuacct\0"
+        "blkio\0"
+        "memory\0"
+        "devices\0";
+
+int cg_create_everywhere(CGroupControllerMask supported, CGroupControllerMask mask, const char *path) {
+        CGroupControllerMask bit = 1;
+        const char *n;
+        int r;
+
+        /* This one will create a cgroup in our private tree, but also
+         * duplicate it in the trees specified in mask, and remove it
+         * in all others */
+
+        /* First create the cgroup in our own hierarchy. */
+        r = cg_create(SYSTEMD_CGROUP_CONTROLLER, path);
+        if (r < 0)
+                return r;
+
+        /* Then, do the same in the other hierarchies */
+        NULSTR_FOREACH(n, mask_names) {
+                if (mask & bit)
+                        cg_create(n, path);
+                else if (supported & bit)
+                        cg_trim(n, path, true);
+
+                bit <<= 1;
+        }
+
+        return 0;
+}
+
+int cg_attach_everywhere(CGroupControllerMask supported, const char *path, pid_t pid, cg_migrate_callback_t path_callback, void *userdata) {
+        CGroupControllerMask bit = 1;
+        const char *n;
+        int r;
+
+        r = cg_attach(SYSTEMD_CGROUP_CONTROLLER, path, pid);
+        if (r < 0)
+                return r;
+
+        NULSTR_FOREACH(n, mask_names) {
+
+                if (supported & bit) {
+                        const char *p = NULL;
+
+                        if (path_callback)
+                                p = path_callback(bit, userdata);
+
+                        if (!p)
+                                p = path;
+
+                        cg_attach_fallback(n, path, pid);
+                }
+
+                bit <<= 1;
+        }
+
+        return 0;
+}
+
+int cg_attach_many_everywhere(CGroupControllerMask supported, const char *path, Set* pids, cg_migrate_callback_t path_callback, void *userdata) {
+        Iterator i;
+        void *pidp;
+        int r = 0;
+
+        SET_FOREACH(pidp, pids, i) {
+                pid_t pid = PTR_TO_LONG(pidp);
+                int q;
+
+                q = cg_attach_everywhere(supported, path, pid, path_callback, userdata);
+                if (q < 0)
+                        r = q;
+        }
+
+        return r;
+}
+
+int cg_migrate_everywhere(CGroupControllerMask supported, const char *from, const char *to, cg_migrate_callback_t to_callback, void *userdata) {
+        CGroupControllerMask bit = 1;
+        const char *n;
+        int r;
+
+        if (!path_equal(from, to))  {
+                r = cg_migrate_recursive(SYSTEMD_CGROUP_CONTROLLER, from, SYSTEMD_CGROUP_CONTROLLER, to, false, true);
+                if (r < 0)
+                        return r;
+        }
+
+        NULSTR_FOREACH(n, mask_names) {
+                if (supported & bit) {
+                        const char *p = NULL;
+
+                        if (to_callback)
+                                p = to_callback(bit, userdata);
+
+                        if (!p)
+                                p = to;
+
+                        cg_migrate_recursive_fallback(SYSTEMD_CGROUP_CONTROLLER, to, n, p, false, false);
+                }
+
+                bit <<= 1;
+        }
+
+        return 0;
+}
+
+int cg_trim_everywhere(CGroupControllerMask supported, const char *path, bool delete_root) {
+        CGroupControllerMask bit = 1;
+        const char *n;
+        int r;
+
+        r = cg_trim(SYSTEMD_CGROUP_CONTROLLER, path, delete_root);
+        if (r < 0)
+                return r;
+
+        NULSTR_FOREACH(n, mask_names) {
+                if (supported & bit)
+                        cg_trim(n, path, delete_root);
+
+                bit <<= 1;
+        }
+
+        return 0;
+}
+
+CGroupControllerMask cg_mask_supported(void) {
+        CGroupControllerMask bit = 1, mask = 0;
+        const char *n;
+
+        NULSTR_FOREACH(n, mask_names) {
+                if (check_hierarchy(n) >= 0)
+                        mask |= bit;
+
+                bit <<= 1;
+        }
+
+        return mask;
+}
+
+int cg_kernel_controllers(Set *controllers) {
+        _cleanup_fclose_ FILE *f = NULL;
+        char buf[LINE_MAX];
+        int r;
+
+        assert(controllers);
+
+        f = fopen("/proc/cgroups", "re");
+        if (!f) {
+                if (errno == ENOENT)
+                        return 0;
+                return -errno;
+        }
+
+        /* Ignore the header line */
+        (void) fgets(buf, sizeof(buf), f);
+
+        for (;;) {
+                char *controller;
+                int enabled = 0;
+
+                errno = 0;
+                if (fscanf(f, "%ms %*i %*i %i", &controller, &enabled) != 2) {
+
+                        if (feof(f))
+                                break;
+
+                        if (ferror(f) && errno)
+                                return -errno;
+
+                        return -EBADMSG;
+                }
+
+                if (!enabled) {
+                        free(controller);
+                        continue;
+                }
+
+                if (!filename_is_valid(controller)) {
+                        free(controller);
+                        return -EBADMSG;
+                }
+
+                r = set_consume(controllers, controller);
+                if (r < 0)
+                        return r;
+        }
+
+        return 0;
+}