udevd: make cgroup logic independent of socket passing

This should have no behavioural change, but it is odd to tie the cgroup cleaning to
whether or not we are passed sockets.

The point really is if we are guaranteed to be in a dedicated cgroup, so instead
check for our parent being PID1 (we already implicitly only do this on systemd
systems).

1 files changed, 15 insertions, 9 deletions

diff --git a/src/udev/udevd.c b/src/udev/udevd.c
index ccdec3de43..121491753a 100644
--- a/src/udev/udevd.c
+++ b/src/udev/udevd.c
@@ -69,7 +69,7 @@ typedef struct Manager {
         sd_event *event;
         Hashmap *workers;
         struct udev_list_node events;
-        char *cgroup;
+        const char *cgroup;
         pid_t pid; /* the process that originally allocated the manager object */
 
         struct udev_rules *rules;
@@ -307,7 +307,6 @@ static void manager_free(Manager *manager) {
 
         udev_list_cleanup(&manager->properties);
         udev_rules_unref(manager->rules);
-        free(manager->cgroup);
 
         safe_close(manager->fd_inotify);
         safe_close_pair(manager->worker_watch);
@@ -1443,7 +1442,7 @@ static int parse_argv(int argc, char *argv[]) {
         return 1;
 }
 
-static int manager_new(Manager **ret) {
+static int manager_new(Manager **ret, const char *cgroup) {
         _cleanup_(manager_freep) Manager *manager = NULL;
         int r, fd_ctrl, fd_uevent;
 
@@ -1470,6 +1469,8 @@ static int manager_new(Manager **ret) {
         udev_list_node_init(&manager->events);
         udev_list_init(manager->udev, &manager->properties, true);
 
+        manager->cgroup = cgroup;
+
         r = listen_fds(&fd_ctrl, &fd_uevent);
         if (r >= 0) {
                 /* get control and netlink socket from systemd */
@@ -1480,11 +1481,6 @@ static int manager_new(Manager **ret) {
                 manager->monitor = udev_monitor_new_from_netlink_fd(manager->udev, "kernel", fd_uevent);
                 if (!manager->monitor)
                         return log_error_errno(EINVAL, "error taking over netlink socket");
-
-                /* get our own cgroup, we regularly kill everything udev has left behind */
-                r = cg_pid_get_path(SYSTEMD_CGROUP_CONTROLLER, 0, &manager->cgroup);
-                if (r < 0)
-                        log_warning_errno(r, "failed to get cgroup: %m");
         } else {
                 /* open control and netlink socket */
                 manager->ctrl = udev_ctrl_new(manager->udev);
@@ -1598,6 +1594,7 @@ static int manager_listen(Manager *manager) {
 
 int main(int argc, char *argv[]) {
         _cleanup_(manager_freep) Manager *manager = NULL;
+        _cleanup_free_ char *cgroup = NULL;
         int r;
 
         log_set_target(LOG_TARGET_AUTO);
@@ -1655,7 +1652,16 @@ int main(int argc, char *argv[]) {
 
         dev_setup(NULL, UID_INVALID, GID_INVALID);
 
-        r = manager_new(&manager);
+        if (getppid() == 1) {
+                /* get our own cgroup, we regularly kill everything udev has left behind
+                   we only do this on systemd systems, and only if we are directly spawned
+                   by PID1. otherwise we are not guaranteed to have a dedicated cgroup */
+                r = cg_pid_get_path(SYSTEMD_CGROUP_CONTROLLER, 0, &cgroup);
+                if (r < 0)
+                        log_warning_errno(r, "failed to get cgroup: %m");
+        }
+
+        r = manager_new(&manager, cgroup);
         if (r < 0)
                 goto exit;