#define RECHECK_SPACE_USEC (30*USEC_PER_SEC)
+#define NOTIFY_SNDBUF_SIZE (8*1024*1024)
+
static int determine_space_for(
Server *s,
JournalMetrics *metrics,
return 0;
}
+static int dispatch_notify_event(sd_event_source *es, int fd, uint32_t revents, void *userdata) {
+ Server *s = userdata;
+ int r;
+
+ assert(s);
+ assert(s->notify_event_source == es);
+ assert(s->notify_fd == fd);
+
+ if (revents != EPOLLOUT) {
+ log_error("Invalid events on notify file descriptor.");
+ return -EINVAL;
+ }
+
+ /* The $NOTIFY_SOCKET is writable again, now send exactly one
+ * message on it. Either it's the initial READY=1 event or an
+ * stdout stream event. If there's nothing to write anymore,
+ * turn our event source off. The next time there's something
+ * to send it will be turned on again. */
+
+ if (!s->sent_notify_ready) {
+ static const char p[] =
+ "READY=1\n"
+ "STATUS=Processing requests...";
+ ssize_t l;
+
+ l = send(s->notify_fd, p, strlen(p), MSG_DONTWAIT);
+ if (l < 0) {
+ if (errno == EAGAIN)
+ return 0;
+
+ return log_error_errno(errno, "Failed to send READY=1 notification message: %m");
+ }
+
+ s->sent_notify_ready = true;
+ log_debug("Sent READY=1 notification.");
+
+ } else if (s->stdout_streams_notify_queue)
+ /* Dispatch one stream notification event */
+ stdout_stream_send_notify(s->stdout_streams_notify_queue);
+
+ /* Leave us enabled if there's still more to to do. */
+ if (s->stdout_streams_notify_queue)
+ return 0;
+
+ /* There was nothing to do anymore, let's turn ourselves off. */
+ r = sd_event_source_set_enabled(es, SD_EVENT_OFF);
+ if (r < 0)
+ return log_error_errno(r, "Failed to turn off notify event source: %m");
+
+ return 0;
+}
+
+static int server_connect_notify(Server *s) {
+ union sockaddr_union sa = {
+ .un.sun_family = AF_UNIX,
+ };
+ const char *e;
+ int r;
+
+ assert(s);
+ assert(s->notify_fd < 0);
+ assert(!s->notify_event_source);
+
+ /*
+ So here's the problem: we'd like to send notification
+ messages to PID 1, but we cannot do that via sd_notify(),
+ since that's synchronous, and we might end up blocking on
+ it. Specifically: given that PID 1 might block on
+ dbus-daemon during IPC, and dbus-daemon is logging to us,
+ and might hence block on us, we might end up in a deadlock
+ if we block on sending PID 1 notification messages -- by
+ generating a full blocking circle. To avoid this, let's
+ create a non-blocking socket, and connect it to the
+ notification socket, and then wait for POLLOUT before we
+ send anything. This should efficiently avoid any deadlocks,
+ as we'll never block on PID 1, hence PID 1 can safely block
+ on dbus-daemon which can safely block on us again.
+
+ Don't think that this issue is real? It is, see:
+ https://github.com/systemd/systemd/issues/1505
+ */
+
+ e = getenv("NOTIFY_SOCKET");
+ if (!e)
+ return 0;
+
+ if ((e[0] != '@' && e[0] != '/') || e[1] == 0) {
+ log_error("NOTIFY_SOCKET set to an invalid value: %s", e);
+ return -EINVAL;
+ }
+
+ if (strlen(e) > sizeof(sa.un.sun_path)) {
+ log_error("NOTIFY_SOCKET path too long: %s", e);
+ return -EINVAL;
+ }
+
+ s->notify_fd = socket(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
+ if (s->notify_fd < 0)
+ return log_error_errno(errno, "Failed to create notify socket: %m");
+
+ (void) fd_inc_sndbuf(s->notify_fd, NOTIFY_SNDBUF_SIZE);
+
+ strncpy(sa.un.sun_path, e, sizeof(sa.un.sun_path));
+ if (sa.un.sun_path[0] == '@')
+ sa.un.sun_path[0] = 0;
+
+ r = connect(s->notify_fd, &sa.sa, offsetof(struct sockaddr_un, sun_path) + strlen(e));
+ if (r < 0)
+ return log_error_errno(errno, "Failed to connect to notify socket: %m");
+
+ r = sd_event_add_io(s->event, &s->notify_event_source, s->notify_fd, EPOLLOUT, dispatch_notify_event, s);
+ if (r < 0)
+ return log_error_errno(r, "Failed to watch notification socket: %m");
+
+ /* This should fire pretty soon, which we'll use to send the
+ * READY=1 event. */
+
+ return 0;
+}
+
int server_init(Server *s) {
_cleanup_fdset_free_ FDSet *fds = NULL;
int n, r, fd;
assert(s);
zero(*s);
- s->syslog_fd = s->native_fd = s->stdout_fd = s->dev_kmsg_fd = s->audit_fd = s->hostname_fd = -1;
+ s->syslog_fd = s->native_fd = s->stdout_fd = s->dev_kmsg_fd = s->audit_fd = s->hostname_fd = s->notify_fd = -1;
s->compress = true;
s->seal = true;
if (r < 0)
return log_error_errno(r, "Failed to create event loop: %m");
- sd_event_set_watchdog(s->event, true);
-
n = sd_listen_fds(true);
if (n < 0)
return log_error_errno(n, "Failed to read listening file descriptors from environment: %m");
server_cache_boot_id(s);
server_cache_machine_id(s);
+ (void) server_connect_notify(s);
+
return system_journal_open(s, false);
}
sd_event_source_unref(s->sigterm_event_source);
sd_event_source_unref(s->sigint_event_source);
sd_event_source_unref(s->hostname_event_source);
+ sd_event_source_unref(s->notify_event_source);
sd_event_unref(s->event);
safe_close(s->syslog_fd);
safe_close(s->dev_kmsg_fd);
safe_close(s->audit_fd);
safe_close(s->hostname_fd);
+ safe_close(s->notify_fd);
if (s->rate_limit)
journal_rate_limit_free(s->rate_limit);
bool forward_to_console:1;
bool fdstore:1;
+ bool in_notify_queue:1;
char buffer[LINE_MAX+1];
size_t length;
char *state_file;
LIST_FIELDS(StdoutStream, stdout_stream);
+ LIST_FIELDS(StdoutStream, stdout_stream_notify_queue);
};
void stdout_stream_free(StdoutStream *s) {
assert(s->server->n_stdout_streams > 0);
s->server->n_stdout_streams --;
LIST_REMOVE(stdout_stream, s->server->stdout_streams, s);
+
+ if (s->in_notify_queue)
+ LIST_REMOVE(stdout_stream_notify_queue, s->server->stdout_streams_notify_queue, s);
}
if (s->event_source) {
return;
if (s->state_file)
- unlink(s->state_file);
+ (void) unlink(s->state_file);
stdout_stream_free(s);
}
goto fail;
}
- /* Store the connection fd in PID 1, so that we get it passed
- * in again on next start */
- if (!s->fdstore) {
- sd_pid_notify_with_fds(0, false, "FDSTORE=1", &s->fd, 1);
- s->fdstore = true;
+ if (!s->fdstore && !s->in_notify_queue) {
+ LIST_PREPEND(stdout_stream_notify_queue, s->server->stdout_streams_notify_queue, s);
+ s->in_notify_queue = true;
+
+ if (s->server->notify_event_source) {
+ r = sd_event_source_set_enabled(s->server->notify_event_source, SD_EVENT_ON);
+ if (r < 0)
+ log_warning_errno(r, "Failed to enable notify event source: %m");
+ }
}
return 0;
return 0;
}
+
+void stdout_stream_send_notify(StdoutStream *s) {
+ struct iovec iovec = {
+ .iov_base = (char*) "FDSTORE=1",
+ .iov_len = strlen("FDSTORE=1"),
+ };
+ struct msghdr msghdr = {
+ .msg_iov = &iovec,
+ .msg_iovlen = 1,
+ };
+ struct cmsghdr *cmsg;
+ ssize_t l;
+
+ assert(s);
+ assert(!s->fdstore);
+ assert(s->in_notify_queue);
+ assert(s->server);
+ assert(s->server->notify_fd >= 0);
+
+ /* Store the connection fd in PID 1, so that we get it passed
+ * in again on next start */
+
+ msghdr.msg_controllen = CMSG_SPACE(sizeof(int));
+ msghdr.msg_control = alloca0(msghdr.msg_controllen);
+
+ cmsg = CMSG_FIRSTHDR(&msghdr);
+ cmsg->cmsg_level = SOL_SOCKET;
+ cmsg->cmsg_type = SCM_RIGHTS;
+ cmsg->cmsg_len = CMSG_LEN(sizeof(int));
+
+ memcpy(CMSG_DATA(cmsg), &s->fd, sizeof(int));
+
+ l = sendmsg(s->server->notify_fd, &msghdr, MSG_DONTWAIT|MSG_NOSIGNAL);
+ if (l < 0) {
+ if (errno == EAGAIN)
+ return;
+
+ log_error_errno(errno, "Failed to send stream file descriptor to service manager: %m");
+ } else {
+ log_debug("Successfully sent stream file descriptor to service manager.");
+ s->fdstore = 1;
+ }
+
+ LIST_REMOVE(stdout_stream_notify_queue, s->server->stdout_streams_notify_queue, s);
+ s->in_notify_queue = false;
+
+}
projects / thirdparty / systemd.git / commitdiff
