X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=blobdiff_plain;f=src%2Fshared%2Fcgroup-util.c;h=0d3cc53517de07b7ef779ea5c219f7a052cd566d;hp=2e630d4708d6f14814762794d2fe21345322016e;hb=7d328b544621d4b1bec936dec612947ad8bfb65a;hpb=13b84ec7df103ce388910a2b868fe1668c1e27ef

diff --git a/src/shared/cgroup-util.c b/src/shared/cgroup-util.c
index 2e630d470..0d3cc5351 100644
--- a/src/shared/cgroup-util.c
+++ b/src/shared/cgroup-util.c
@@ -39,6 +39,7 @@
 #include "unit-name.h"
 #include "fileio.h"
 #include "special.h"
+#include "mkdir.h"
 
 int cg_enumerate_processes(const char *controller, const char *path, FILE **_f) {
         _cleanup_free_ char *fs = NULL;
@@ -160,7 +161,7 @@ int cg_kill(const char *controller, const char *path, int sig, bool sigcont, boo
          * tasks list, to properly handle forking processes */
 
         if (!s) {
-                s = allocated_set = set_new(trivial_hash_func, trivial_compare_func);
+                s = allocated_set = set_new(NULL);
                 if (!s)
                         return -ENOMEM;
         }
@@ -193,12 +194,12 @@ int cg_kill(const char *controller, const char *path, int sig, bool sigcont, boo
                         if (kill(pid, sig) < 0) {
                                 if (ret >= 0 && errno != ESRCH)
                                         ret = -errno;
-                        } else if (ret == 0) {
-
-                                if (sigcont)
+                        } else {
+                                if (sigcont && sig != SIGKILL)
                                         kill(pid, SIGCONT);
 
-                                ret = 1;
+                                if (ret == 0)
+                                        ret = 1;
                         }
 
                         done = false;
@@ -238,7 +239,7 @@ int cg_kill_recursive(const char *controller, const char *path, int sig, bool si
         assert(sig >= 0);
 
         if (!s) {
-                s = allocated_set = set_new(trivial_hash_func, trivial_compare_func);
+                s = allocated_set = set_new(NULL);
                 if (!s)
                         return -ENOMEM;
         }
@@ -278,37 +279,6 @@ int cg_kill_recursive(const char *controller, const char *path, int sig, bool si
         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;
@@ -320,7 +290,7 @@ int cg_migrate(const char *cfrom, const char *pfrom, const char *cto, const char
         assert(cto);
         assert(pto);
 
-        s = set_new(trivial_hash_func, trivial_compare_func);
+        s = set_new(NULL);
         if (!s)
                 return -ENOMEM;
 
@@ -456,23 +426,14 @@ int cg_migrate_recursive_fallback(
 
                 /* This didn't work? Then let's try all prefixes of the destination */
 
-                strcpy(prefix, pto);
-                for (;;) {
-                        char *slash;
-
-                        slash = strrchr(prefix, '/');
-                        if (!slash)
-                                break;
-
-                        *slash = 0;
-
+                PATH_FOREACH_PREFIX(prefix, pto) {
                         r = cg_migrate_recursive(cfrom, pfrom, cto, prefix, ignore_self, rem);
                         if (r >= 0)
                                 break;
                 }
         }
 
-        return r;
+        return 0;
 }
 
 static const char *normalize_controller(const char *controller) {
@@ -511,15 +472,13 @@ static int join_path(const char *controller, const char *path, const char *suffi
         if (!t)
                 return -ENOMEM;
 
-        path_kill_slashes(t);
-
-        *fs = t;
+        *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 bool good = false;
+        static thread_local bool good = false;
 
         assert(fs);
 
@@ -543,14 +502,16 @@ int cg_get_path(const char *controller, const char *path, const char *suffix, ch
 }
 
 static int check_hierarchy(const char *p) {
-        char *cc;
+        const char *cc;
 
         assert(p);
 
+        if (!filename_is_valid(p))
+                return 0;
+
         /* 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)
+        cc = strappenda("/sys/fs/cgroup/", p);
+        if (laccess(cc, F_OK) < 0)
                 return -errno;
 
         return 0;
@@ -627,6 +588,46 @@ int cg_delete(const char *controller, const char *path) {
         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];
@@ -642,9 +643,9 @@ int cg_attach(const char *controller, const char *path, pid_t pid) {
         if (pid == 0)
                 pid = getpid();
 
-        snprintf(c, sizeof(c), "%lu\n", (unsigned long) pid);
+        snprintf(c, sizeof(c), PID_FMT"\n", pid);
 
-        return write_string_file(fs, c);
+        return write_string_file_no_create(fs, c);
 }
 
 int cg_attach_fallback(const char *controller, const char *path, pid_t pid) {
@@ -661,23 +662,14 @@ int cg_attach_fallback(const char *controller, const char *path, pid_t pid) {
                 /* This didn't work? Then let's try all prefixes of
                  * the destination */
 
-                strcpy(prefix, path);
-                for (;;) {
-                        char *slash;
-
-                        slash = strrchr(prefix, '/');
-                        if (!slash)
-                                break;
-
-                        *slash = 0;
-
+                PATH_FOREACH_PREFIX(prefix, path) {
                         r = cg_attach(controller, prefix, pid);
                         if (r >= 0)
                                 break;
                 }
         }
 
-        return r;
+        return 0;
 }
 
 int cg_set_group_access(
@@ -692,7 +684,7 @@ int cg_set_group_access(
 
         assert(path);
 
-        if (mode != (mode_t) -1)
+        if (mode != MODE_INVALID)
                 mode &= 0777;
 
         r = cg_get_path(controller, path, NULL, &fs);
@@ -714,10 +706,10 @@ int cg_set_task_access(
 
         assert(path);
 
-        if (mode == (mode_t) -1 && uid == (uid_t) -1 && gid == (gid_t) -1)
+        if (mode == MODE_INVALID && uid == UID_INVALID && gid == GID_INVALID)
                 return 0;
 
-        if (mode != (mode_t) -1)
+        if (mode != MODE_INVALID)
                 mode &= 0666;
 
         r = cg_get_path(controller, path, "cgroup.procs", &fs);
@@ -754,10 +746,7 @@ int cg_pid_get_path(const char *controller, pid_t pid, char **path) {
         } else
                 controller = SYSTEMD_CGROUP_CONTROLLER;
 
-        if (pid == 0)
-                fs = "/proc/self/cgroup";
-        else
-                fs = procfs_file_alloca(pid, "cgroup");
+        fs = procfs_file_alloca(pid, "cgroup");
 
         f = fopen(fs, "re");
         if (!f)
@@ -766,9 +755,9 @@ int cg_pid_get_path(const char *controller, pid_t pid, char **path) {
         cs = strlen(controller);
 
         FOREACH_LINE(line, f, return -errno) {
-                char *l, *p, *w, *e;
+                char *l, *p, *e;
                 size_t k;
-                char *state;
+                const char *word, *state;
                 bool found = false;
 
                 truncate_nl(line);
@@ -784,16 +773,16 @@ int cg_pid_get_path(const char *controller, pid_t pid, char **path) {
 
                 *e = 0;
 
-                FOREACH_WORD_SEPARATOR(w, k, l, ",", state) {
+                FOREACH_WORD_SEPARATOR(word, k, l, ",", state) {
 
-                        if (k == cs && memcmp(w, controller, cs) == 0) {
+                        if (k == cs && memcmp(word, controller, cs) == 0) {
                                 found = true;
                                 break;
                         }
 
                         if (k == 5 + cs &&
-                            memcmp(w, "name=", 5) == 0 &&
-                            memcmp(w+5, controller, cs) == 0) {
+                            memcmp(word, "name=", 5) == 0 &&
+                            memcmp(word+5, controller, cs) == 0) {
                                 found = true;
                                 break;
                         }
@@ -830,7 +819,7 @@ int cg_install_release_agent(const char *controller, const char *agent) {
 
         sc = strstrip(contents);
         if (sc[0] == 0) {
-                r = write_string_file(fs, agent);
+                r = write_string_file_no_create(fs, agent);
                 if (r < 0)
                         return r;
         } else if (!streq(sc, agent))
@@ -850,7 +839,7 @@ int cg_install_release_agent(const char *controller, const char *agent) {
 
         sc = strstrip(contents);
         if (streq(sc, "0")) {
-                r = write_string_file(fs, "1");
+                r = write_string_file_no_create(fs, "1");
                 if (r < 0)
                         return r;
 
@@ -871,7 +860,7 @@ int cg_uninstall_release_agent(const char *controller) {
         if (r < 0)
                 return r;
 
-        r = write_string_file(fs, "0");
+        r = write_string_file_no_create(fs, "0");
         if (r < 0)
                 return r;
 
@@ -882,7 +871,7 @@ int cg_uninstall_release_agent(const char *controller) {
         if (r < 0)
                 return r;
 
-        r = write_string_file(fs, "");
+        r = write_string_file_no_create(fs, "");
         if (r < 0)
                 return r;
 
@@ -918,19 +907,6 @@ int cg_is_empty(const char *controller, const char *path, bool ignore_self) {
         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;
@@ -981,8 +957,7 @@ int cg_split_spec(const char *spec, char **controller, char **path) {
                         if (!t)
                                 return -ENOMEM;
 
-                        path_kill_slashes(t);
-                        *path = t;
+                        *path = path_kill_slashes(t);
                 }
 
                 if (controller)
@@ -1021,19 +996,28 @@ int cg_split_spec(const char *spec, char **controller, char **path) {
                 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;
-        }
+        if (streq(e+1, "")) {
+                u = strdup("/");
+                if (!u) {
+                        free(t);
+                        return -ENOMEM;
+                }
+        } else {
+                u = strdup(e+1);
+                if (!u) {
+                        free(t);
+                        return -ENOMEM;
+                }
 
-        path_kill_slashes(u);
+                if (!path_is_safe(u) ||
+                    !path_is_absolute(u)) {
+                        free(t);
+                        free(u);
+                        return -EINVAL;
+                }
+
+                path_kill_slashes(u);
+        }
 
         if (controller)
                 *controller = t;
@@ -1048,33 +1032,6 @@ int cg_split_spec(const char *spec, char **controller, char **path) {
         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;
@@ -1083,19 +1040,18 @@ int cg_mangle_path(const char *path, char **result) {
         assert(path);
         assert(result);
 
-        /* First check if it already is a filesystem path */
+        /* 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;
+                *result = path_kill_slashes(t);
                 return 0;
         }
 
-        /* Otherwise treat it as cg spec */
+        /* Otherwise, treat it as cg spec */
         r = cg_split_spec(path, &c, &p);
         if (r < 0)
                 return r;
@@ -1121,80 +1077,63 @@ int cg_get_root_path(char **path) {
         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);
+int cg_shift_path(const char *cgroup, const char *root, const char **shifted) {
+        _cleanup_free_ char *rt = NULL;
+        char *p;
+        int r;
 
-                if (streq(p, "systemd")) {
-                        free(*f);
-                        continue;
-                }
+        assert(cgroup);
+        assert(shifted);
 
-                if (!cg_controller_is_valid(p, true)) {
-                        log_warning("Controller %s is not valid, removing from controllers list.", p);
-                        free(*f);
-                        continue;
-                }
+        if (!root) {
+                /* If the root was specified let's use that, otherwise
+                 * let's determine it from PID 1 */
 
-                r = check_hierarchy(p);
-                if (r < 0) {
-                        log_debug("Controller %s is not available, removing from controllers list.", p);
-                        free(*f);
-                        continue;
-                }
+                r = cg_get_root_path(&rt);
+                if (r < 0)
+                        return r;
 
-                *(t++) = *f;
+                root = rt;
         }
 
-        *t = NULL;
-        return strv_uniq(controllers);
+        p = path_startswith(cgroup, root);
+        if (p)
+                *shifted = p - 1;
+        else
+                *shifted = cgroup;
+
+        return 0;
 }
 
-int cg_pid_get_path_shifted(pid_t pid, char **root, char **cgroup) {
-        _cleanup_free_ char *cg_root = NULL;
-        char *cg_process, *p;
+int cg_pid_get_path_shifted(pid_t pid, const char *root, char **cgroup) {
+        _cleanup_free_ char *raw = NULL;
+        const char *c;
         int r;
 
-        r = cg_get_root_path(&cg_root);
+        assert(pid >= 0);
+        assert(cgroup);
+
+        r = cg_pid_get_path(SYSTEMD_CGROUP_CONTROLLER, pid, &raw);
         if (r < 0)
                 return r;
 
-        r = cg_pid_get_path(SYSTEMD_CGROUP_CONTROLLER, pid, &cg_process);
+        r = cg_shift_path(raw, root, &c);
         if (r < 0)
                 return r;
 
-        p = path_startswith(cg_process, cg_root);
-        if (p)
-                p--;
-        else
-                p = cg_process;
-
-        if (cgroup) {
-                char* c;
+        if (c == raw) {
+                *cgroup = raw;
+                raw = NULL;
+        } else {
+                char *n;
 
-                c = strdup(p);
-                if (!c) {
-                        free(cg_process);
+                n = strdup(c);
+                if (!n)
                         return -ENOMEM;
-                }
 
-                *cgroup = c;
+                *cgroup = n;
         }
 
-        if (root) {
-                cg_process[p-cg_process] = 0;
-                *root = cg_process;
-        } else
-                free(cg_process);
-
         return 0;
 }
 
@@ -1208,7 +1147,7 @@ int cg_path_decode_unit(const char *cgroup, char **unit){
         c = strndupa(cgroup, e - cgroup);
         c = cg_unescape(c);
 
-        if (!unit_name_is_valid(c, false))
+        if (!unit_name_is_valid(c, TEMPLATE_INVALID))
                 return -EINVAL;
 
         s = strdup(c);
@@ -1259,6 +1198,9 @@ int cg_pid_get_unit(pid_t pid, char **unit) {
         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;
 
@@ -1267,7 +1209,27 @@ static const char *skip_session(const char *p) {
         p += strspn(p, "/");
 
         n = strcspn(p, "/");
-        if (n <= 12 || memcmp(p, "session-", 8) != 0 || memcmp(p + n - 6, ".scope", 6) != 0)
+        if (n < strlen("session-x.scope") || memcmp(p, "session-", 8) != 0 || memcmp(p + n - 6, ".scope", 6) != 0)
+                return NULL;
+
+        p += n;
+        p += strspn(p, "/");
+
+        return p;
+}
+
+/**
+ * Skip user@*.service, but require it to be there.
+ */
+static const char *skip_user_manager(const char *p) {
+        size_t n;
+
+        assert(p);
+
+        p += strspn(p, "/");
+
+        n = strcspn(p, "/");
+        if (n < strlen("user@x.service") || memcmp(p, "user@", 5) != 0 || memcmp(p + n - 8, ".service", 8) != 0)
                 return NULL;
 
         p += n;
@@ -1277,7 +1239,7 @@ static const char *skip_session(const char *p) {
 }
 
 int cg_path_get_user_unit(const char *path, char **unit) {
-        const char *e;
+        const char *e, *t;
 
         assert(path);
         assert(unit);
@@ -1289,13 +1251,17 @@ int cg_path_get_user_unit(const char *path, char **unit) {
         /* Skip slices, if there are any */
         e = skip_slices(path);
 
-        /* Skip the session scope, require that there is one */
-        e = skip_session(e);
-        if (!e)
-                return -ENOENT;
-
-        /* And skip more slices */
-        e = skip_slices(e);
+        /* Skip the session scope... */
+        t = skip_session(e);
+        if (t)
+                /* ... and skip more slices if there's one */
+                e = skip_slices(t);
+        else {
+                /* ... or require a user manager unit to be there */
+                e = skip_user_manager(e);
+                if (!e)
+                        return -ENOENT;
+        }
 
         return cg_path_decode_unit(e, unit);
 }
@@ -1314,39 +1280,18 @@ int cg_pid_get_user_unit(pid_t pid, char **unit) {
 }
 
 int cg_path_get_machine_name(const char *path, char **machine) {
-        const char *e, *n, *x;
-        char *s, *r;
-        size_t l;
-
-        assert(path);
-        assert(machine);
-
-        /* Skip slices, if there are any */
-        e = skip_slices(path);
-
-        n = strchrnul(e, '/');
-        if (e == n)
-                return -ENOENT;
-
-        s = strndupa(e, n - e);
-        s = cg_unescape(s);
-
-        x = startswith(s, "machine-");
-        if (!x)
-                return -ENOENT;
-        if (!endswith(x, ".scope"))
-                return -ENOENT;
+        _cleanup_free_ char *u = NULL, *sl = NULL;
+        int r;
 
-        l = strlen(x);
-        if (l <= 6)
-                return -ENOENT;
+        r = cg_path_get_unit(path, &u);
+        if (r < 0)
+                return r;
 
-        r = strndup(x, l - 6);
-        if (!r)
+        sl = strjoin("/run/systemd/machines/unit:", u, NULL);
+        if (!sl)
                 return -ENOMEM;
 
-        *machine = r;
-        return 0;
+        return readlink_malloc(sl, machine);
 }
 
 int cg_pid_get_machine_name(pid_t pid, char **machine) {
@@ -1363,12 +1308,10 @@ int cg_pid_get_machine_name(pid_t pid, char **machine) {
 }
 
 int cg_path_get_session(const char *path, char **session) {
-        const char *e, *n, *x;
-        char *s, *r;
-        size_t l;
+        const char *e, *n, *x, *y;
+        char *s;
 
         assert(path);
-        assert(session);
 
         /* Skip slices, if there are any */
         e = skip_slices(path);
@@ -1383,18 +1326,20 @@ int cg_path_get_session(const char *path, char **session) {
         x = startswith(s, "session-");
         if (!x)
                 return -ENOENT;
-        if (!endswith(x, ".scope"))
+        y = endswith(x, ".scope");
+        if (!y || x == y)
                 return -ENOENT;
 
-        l = strlen(x);
-        if (l <= 6)
-                return -ENOENT;
+        if (session) {
+                char *r;
 
-        r = strndup(x, l - 6);
-        if (!r)
-                return -ENOMEM;
+                r = strndup(x, y - x);
+                if (!r)
+                        return -ENOMEM;
+
+                *session = r;
+        }
 
-        *session = r;
         return 0;
 }
 
@@ -1402,8 +1347,6 @@ 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;
@@ -1413,36 +1356,41 @@ int cg_pid_get_session(pid_t pid, char **session) {
 
 int cg_path_get_owner_uid(const char *path, uid_t *uid) {
         _cleanup_free_ char *slice = NULL;
-        const char *e;
+        const char *start, *end;
         char *s;
+        uid_t u;
         int r;
 
         assert(path);
-        assert(uid);
 
         r = cg_path_get_slice(path, &slice);
         if (r < 0)
                 return r;
 
-        e = startswith(slice, "user-");
-        if (!e)
+        start = startswith(slice, "user-");
+        if (!start)
                 return -ENOENT;
-        if (!endswith(slice, ".slice"))
+        end = endswith(slice, ".slice");
+        if (!end)
                 return -ENOENT;
 
-        s = strndupa(e, strlen(e) - 6);
+        s = strndupa(start, end - start);
         if (!s)
-                return -ENOMEM;
+                return -ENOENT;
+
+        if (parse_uid(s, &u) < 0)
+                return -EIO;
+
+        if (uid)
+                *uid = u;
 
-        return parse_uid(s, uid);
+        return 0;
 }
 
 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;
@@ -1497,35 +1445,6 @@ int cg_pid_get_slice(pid_t pid, char **slice) {
         return cg_path_get_slice(cgroup, slice);
 }
 
-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;
 
@@ -1619,7 +1538,7 @@ int cg_slice_to_path(const char *unit, char **ret) {
         assert(unit);
         assert(ret);
 
-        if (!unit_name_is_valid(unit, false))
+        if (!unit_name_is_valid(unit, TEMPLATE_INVALID))
                 return -EINVAL;
 
         if (!endswith(unit, ".slice"))
@@ -1636,7 +1555,7 @@ int cg_slice_to_path(const char *unit, char **ret) {
 
                 strcpy(stpncpy(n, p, dash - p), ".slice");
 
-                if (!unit_name_is_valid(n, false))
+                if (!unit_name_is_valid(n, TEMPLATE_INVALID))
                         return -EINVAL;
 
                 escaped = cg_escape(n);
@@ -1670,7 +1589,18 @@ int cg_set_attribute(const char *controller, const char *path, const char *attri
         if (r < 0)
                 return r;
 
-        return write_string_file(p, value);
+        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[] =
@@ -1707,7 +1637,7 @@ int cg_create_everywhere(CGroupControllerMask supported, CGroupControllerMask ma
         return 0;
 }
 
-int cg_attach_everywhere(CGroupControllerMask supported, const char *path, pid_t pid) {
+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;
@@ -1717,8 +1647,18 @@ int cg_attach_everywhere(CGroupControllerMask supported, const char *path, pid_t
                 return r;
 
         NULSTR_FOREACH(n, mask_names) {
-                if (supported & bit)
+
+                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;
         }
@@ -1726,7 +1666,7 @@ int cg_attach_everywhere(CGroupControllerMask supported, const char *path, pid_t
         return 0;
 }
 
-int cg_attach_many_everywhere(CGroupControllerMask supported, const char *path, Set* pids) {
+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;
@@ -1735,7 +1675,7 @@ int cg_attach_many_everywhere(CGroupControllerMask supported, const char *path,
                 pid_t pid = PTR_TO_LONG(pidp);
                 int q;
 
-                q = cg_attach_everywhere(supported, path, pid);
+                q = cg_attach_everywhere(supported, path, pid, path_callback, userdata);
                 if (q < 0)
                         r = q;
         }
@@ -1743,7 +1683,7 @@ int cg_attach_many_everywhere(CGroupControllerMask supported, const char *path,
         return r;
 }
 
-int cg_migrate_everywhere(CGroupControllerMask supported, const char *from, const char *to) {
+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;
@@ -1755,8 +1695,17 @@ int cg_migrate_everywhere(CGroupControllerMask supported, const char *from, cons
         }
 
         NULSTR_FOREACH(n, mask_names) {
-                if (supported & bit)
-                        cg_migrate_recursive_fallback(SYSTEMD_CGROUP_CONTROLLER, to, n, to, false, false);
+                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;
         }
@@ -1796,3 +1745,54 @@ CGroupControllerMask cg_mask_supported(void) {
 
         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;
+}