tree-wide: warn when sd_notify fails with READY=1 or FDSTOREREMOVE=1

Most sd_notify() calls are like log_info() — the result is only informative
and if they fail, it's best ignore this. But if a call with READY=1 fails,
the unit may enter a failed state, so we should warn about this. Similarly
for FSTOREREMOVE=1: the manager may be left with a stale fd, at least wasting
resources.

src/machine/machined.c

@@ -6,14 +6,13 @@
 #include <sys/types.h>
 #include <unistd.h>
 
-#include "sd-daemon.h"
-
 #include "alloc-util.h"
 #include "bus-error.h"
 #include "bus-locator.h"
 #include "bus-log-control-api.h"
 #include "bus-polkit.h"
 #include "cgroup-util.h"
+#include "daemon-util.h"
 #include "dirent-util.h"
 #include "discover-image.h"
 #include "fd-util.h"
@@ -352,17 +351,14 @@ static int run(int argc, char *argv[]) {
                 return log_error_errno(r, "Failed to fully start up daemon: %m");
 
         log_debug("systemd-machined running as pid "PID_FMT, getpid_cached());
-        (void) sd_notify(false,
-                         "READY=1\n"
-                         "STATUS=Processing requests...");
+        r = sd_notify(false, NOTIFY_READY);
+        if (r < 0)
+                log_warning_errno(r, "Failed to send readiness notification, ignoring: %m");
 
         r = manager_run(m);
 
+        (void) sd_notify(false, NOTIFY_STOPPING);
         log_debug("systemd-machined stopped as pid "PID_FMT, getpid_cached());
-        (void) sd_notify(false,
-                         "STOPPING=1\n"
-                         "STATUS=Shutting down...");
-
         return r;
 }