#include "watchdog.h"
#define NOTIFY_RCVBUF_SIZE (8*1024*1024)
+#define CGROUPS_AGENT_RCVBUF_SIZE (8*1024*1024)
/* Initial delay and the interval for printing status messages about running jobs */
#define JOBS_IN_PROGRESS_WAIT_USEC (5*USEC_PER_SEC)
#define JOBS_IN_PROGRESS_PERIOD_DIVISOR 3
static int manager_dispatch_notify_fd(sd_event_source *source, int fd, uint32_t revents, void *userdata);
+static int manager_dispatch_cgroups_agent_fd(sd_event_source *source, int fd, uint32_t revents, void *userdata);
static int manager_dispatch_signal_fd(sd_event_source *source, int fd, uint32_t revents, void *userdata);
static int manager_dispatch_time_change_fd(sd_event_source *source, int fd, uint32_t revents, void *userdata);
static int manager_dispatch_idle_pipe_fd(sd_event_source *source, int fd, uint32_t revents, void *userdata);
(void) sd_event_source_set_description(m->signal_event_source, "manager-signal");
- /* Process signals a bit earlier than the rest of things, but
- * later than notify_fd processing, so that the notify
- * processing can still figure out to which process/service a
- * message belongs, before we reap the process. */
- r = sd_event_source_set_priority(m->signal_event_source, SD_EVENT_PRIORITY_NORMAL-5);
+ /* Process signals a bit earlier than the rest of things, but later than notify_fd processing, so that the
+ * notify processing can still figure out to which process/service a message belongs, before we reap the
+ * process. Also, process this before handling cgroup notifications, so that we always collect child exit
+ * status information before detecting that there's no process in a cgroup. */
+ r = sd_event_source_set_priority(m->signal_event_source, SD_EVENT_PRIORITY_NORMAL-6);
if (r < 0)
return r;
m->idle_pipe[0] = m->idle_pipe[1] = m->idle_pipe[2] = m->idle_pipe[3] = -1;
- m->pin_cgroupfs_fd = m->notify_fd = m->signal_fd = m->time_change_fd =
- m->dev_autofs_fd = m->private_listen_fd = m->kdbus_fd = m->cgroup_inotify_fd = -1;
+ m->pin_cgroupfs_fd = m->notify_fd = m->cgroups_agent_fd = m->signal_fd = m->time_change_fd =
+ m->dev_autofs_fd = m->private_listen_fd = m->kdbus_fd = m->cgroup_inotify_fd =
+ m->ask_password_inotify_fd = -1;
m->current_job_id = 1; /* start as id #1, so that we can leave #0 around as "null-like" value */
- m->ask_password_inotify_fd = -1;
m->have_ask_password = -EINVAL; /* we don't know */
m->first_boot = -1;
if (r < 0)
return log_error_errno(r, "Failed to allocate notify event source: %m");
- /* Process signals a bit earlier than SIGCHLD, so that we can
- * still identify to which service an exit message belongs */
+ /* Process notification messages a bit earlier than SIGCHLD, so that we can still identify to which
+ * service an exit message belongs. */
r = sd_event_source_set_priority(m->notify_event_source, SD_EVENT_PRIORITY_NORMAL-7);
if (r < 0)
return log_error_errno(r, "Failed to set priority of notify event source: %m");
return 0;
}
+static int manager_setup_cgroups_agent(Manager *m) {
+
+ static const union sockaddr_union sa = {
+ .un.sun_family = AF_UNIX,
+ .un.sun_path = "/run/systemd/cgroups-agent",
+ };
+ int r;
+
+ /* This creates a listening socket we receive cgroups agent messages on. We do not use D-Bus for delivering
+ * these messages from the cgroups agent binary to PID 1, as the cgroups agent binary is very short-living, and
+ * each instance of it needs a new D-Bus connection. Since D-Bus connections are SOCK_STREAM/AF_UNIX, on
+ * overloaded systems the backlog of the D-Bus socket becomes relevant, as not more than the configured number
+ * of D-Bus connections may be queued until the kernel will start dropping further incoming connections,
+ * possibly resulting in lost cgroups agent messages. To avoid this, we'll use a private SOCK_DGRAM/AF_UNIX
+ * socket, where no backlog is relevant as communication may take place without an actual connect() cycle, and
+ * we thus won't lose messages.
+ *
+ * Note that PID 1 will forward the agent message to system bus, so that the user systemd instance may listen
+ * to it. The system instance hence listens on this special socket, but the user instances listen on the system
+ * bus for these messages. */
+
+ if (m->test_run)
+ return 0;
+
+ if (!MANAGER_IS_SYSTEM(m))
+ return 0;
+
+ if (cg_unified() > 0) /* We don't need this anymore on the unified hierarchy */
+ return 0;
+
+ if (m->cgroups_agent_fd < 0) {
+ _cleanup_close_ int fd = -1;
+
+ /* First free all secondary fields */
+ m->cgroups_agent_event_source = sd_event_source_unref(m->cgroups_agent_event_source);
+
+ fd = socket(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
+ if (fd < 0)
+ return log_error_errno(errno, "Failed to allocate cgroups agent socket: %m");
+
+ fd_inc_rcvbuf(fd, CGROUPS_AGENT_RCVBUF_SIZE);
+
+ (void) unlink(sa.un.sun_path);
+
+ /* Only allow root to connect to this socket */
+ RUN_WITH_UMASK(0077)
+ r = bind(fd, &sa.sa, offsetof(struct sockaddr_un, sun_path) + strlen(sa.un.sun_path));
+ if (r < 0)
+ return log_error_errno(errno, "bind(%s) failed: %m", sa.un.sun_path);
+
+ m->cgroups_agent_fd = fd;
+ fd = -1;
+ }
+
+ if (!m->cgroups_agent_event_source) {
+ r = sd_event_add_io(m->event, &m->cgroups_agent_event_source, m->cgroups_agent_fd, EPOLLIN, manager_dispatch_cgroups_agent_fd, m);
+ if (r < 0)
+ return log_error_errno(r, "Failed to allocate cgroups agent event source: %m");
+
+ /* Process cgroups notifications early, but after having processed service notification messages or
+ * SIGCHLD signals, so that a cgroup running empty is always just the last safety net of notification,
+ * and we collected the metadata the notification and SIGCHLD stuff offers first. Also see handling of
+ * cgroup inotify for the unified cgroup stuff. */
+ r = sd_event_source_set_priority(m->cgroups_agent_event_source, SD_EVENT_PRIORITY_NORMAL-5);
+ if (r < 0)
+ return log_error_errno(r, "Failed to set priority of cgroups agent event source: %m");
+
+ (void) sd_event_source_set_description(m->cgroups_agent_event_source, "manager-cgroups-agent");
+ }
+
+ return 0;
+}
+
static int manager_setup_kdbus(Manager *m) {
_cleanup_free_ char *p = NULL;
sd_event_source_unref(m->signal_event_source);
sd_event_source_unref(m->notify_event_source);
+ sd_event_source_unref(m->cgroups_agent_event_source);
sd_event_source_unref(m->time_change_event_source);
sd_event_source_unref(m->jobs_in_progress_event_source);
sd_event_source_unref(m->run_queue_event_source);
safe_close(m->signal_fd);
safe_close(m->notify_fd);
+ safe_close(m->cgroups_agent_fd);
safe_close(m->time_change_fd);
safe_close(m->kdbus_fd);
if (q < 0 && r == 0)
r = q;
+ q = manager_setup_cgroups_agent(m);
+ if (q < 0 && r == 0)
+ r = q;
+
/* We might have deserialized the kdbus control fd, but if we
* didn't, then let's create the bus now. */
manager_setup_kdbus(m);
return n;
}
+static int manager_dispatch_cgroups_agent_fd(sd_event_source *source, int fd, uint32_t revents, void *userdata) {
+ Manager *m = userdata;
+ char buf[PATH_MAX+1];
+ ssize_t n;
+
+ n = recv(fd, buf, sizeof(buf), 0);
+ if (n < 0)
+ return log_error_errno(errno, "Failed to read cgroups agent message: %m");
+ if (n == 0) {
+ log_error("Got zero-length cgroups agent message, ignoring.");
+ return 0;
+ }
+ if ((size_t) n >= sizeof(buf)) {
+ log_error("Got overly long cgroups agent message, ignoring.");
+ return 0;
+ }
+
+ if (memchr(buf, 0, n)) {
+ log_error("Got cgroups agent message with embedded NUL byte, ignoring.");
+ return 0;
+ }
+ buf[n] = 0;
+
+ manager_notify_cgroup_empty(m, buf);
+ bus_forward_agent_released(m, buf);
+
+ return 0;
+}
+
static void manager_invoke_notify_message(Manager *m, Unit *u, pid_t pid, const char *buf, size_t n, FDSet *fds) {
_cleanup_strv_free_ char **tags = NULL;
fprintf(f, "notify-socket=%s\n", m->notify_socket);
}
+ if (m->cgroups_agent_fd >= 0) {
+ int copy;
+
+ copy = fdset_put_dup(fds, m->cgroups_agent_fd);
+ if (copy < 0)
+ return copy;
+
+ fprintf(f, "cgroups-agent-fd=%i\n", copy);
+ }
+
if (m->kdbus_fd >= 0) {
int copy;
free(m->notify_socket);
m->notify_socket = n;
+ } else if (startswith(l, "cgroups-agent-fd=")) {
+ int fd;
+
+ if (safe_atoi(l + 17, &fd) < 0 || fd < 0 || !fdset_contains(fds, fd))
+ log_debug("Failed to parse cgroups agent fd: %s", l + 10);
+ else {
+ m->cgroups_agent_event_source = sd_event_source_unref(m->cgroups_agent_event_source);
+ safe_close(m->cgroups_agent_fd);
+ m->cgroups_agent_fd = fdset_remove(fds, fd);
+ }
+
} else if (startswith(l, "kdbus-fd=")) {
int fd;
if (q < 0 && r >= 0)
r = q;
+ q = manager_setup_cgroups_agent(m);
+ if (q < 0 && r >= 0)
+ r = q;
+
/* Third, fire things up! */
manager_coldplug(m);
projects / thirdparty / systemd.git / blobdiff