Handle event loop watcher failure modes

When alibuEv event watcher callback has `UEV_ERROR` in the events mask
we must handle the error.  Unfortunately, in most cases there is not
much we can do but ignore it or log the error.

Signed-off-by: Joachim Nilsson <troglobit@gmail.com>

src/api.c

@@ -173,6 +173,11 @@ static void cb(uev_t *w, void *arg, int events)
 	int sd, lvl;
 	struct init_request rq;
 
+	if (UEV_ERROR == events) {
+		_e("Unrecoverable error on API socket");
+		return;
+	}
+
 	sd = accept(w->fd, NULL, NULL);
 	if (sd < 0) {
 		_pe("Failed serving API request");

src/inetd.c

@@ -142,7 +142,12 @@ static void socket_cb(uev_t *w, void *arg, int events)
 	svc_t *svc = (svc_t *)arg, *task;
 	int stdin;
 
-	_d("Got event on %s socket ...", svc->cmd);
+	_d("%s: Got socket event ...", svc->cmd);
+	if (UEV_ERROR == events) {
+		logit(LOG_INFO, "%s: Socket error, aborting: %m", svc->cmd);
+		return;
+	}
+
 	stdin = get_stdin(svc);
 	if (stdin < 0) {
 		logit(LOG_CRIT, "%s: Unable to accept incoming connection", svc->cmd);

src/service.c

@@ -82,6 +82,7 @@ static void service_timeout_cb(uev_t *w, void *arg, int events)
 {
 	svc_t *svc = arg;
 
+	/* Ignore any UEV_ERROR, we're a one-shot cb so just run it. */
 	svc->timer_cb(svc);
 }
 

src/sig.c

@@ -224,6 +224,11 @@ void do_shutdown(shutop_t op)
 static void sighup_cb(uev_t *w, void *arg, int events)
 {
 	_d("...");
+	if (UEV_ERROR == events) {
+		_e("Unrecoverable error in signal watcher");
+		return;
+	}
+
 	/* INIT_CMD_RELOAD: 'init q', 'initctl reload', and SIGHUP */
 	service_reload_dynamic();
 }
@@ -234,6 +239,11 @@ static void sighup_cb(uev_t *w, void *arg, int events)
 static void sigint_cb(uev_t *w, void *arg, int events)
 {
 	_d("...");
+	if (UEV_ERROR == events) {
+		_e("Unrecoverable error in signal watcher");
+		return;
+	}
+
 	halt = SHUT_REBOOT;
 	service_runlevel(6);
 }
@@ -244,6 +254,11 @@ static void sigint_cb(uev_t *w, void *arg, int events)
 static void sigusr1_cb(uev_t *w, void *arg, int events)
 {
 	_d("...");
+	if (UEV_ERROR == events) {
+		_e("Unrecoverable error in signal watcher");
+		return;
+	}
+
 	halt = SHUT_HALT;
 	service_runlevel(0);
 }
@@ -254,6 +269,11 @@ static void sigusr1_cb(uev_t *w, void *arg, int events)
 static void sigusr2_cb(uev_t *w, void *arg, int events)
 {
 	_d("...");
+	if (UEV_ERROR == events) {
+		_e("Unrecoverable error in signal watcher");
+		return;
+	}
+
 	halt = SHUT_OFF;
 	service_runlevel(0);
 }
@@ -264,6 +284,11 @@ static void sigusr2_cb(uev_t *w, void *arg, int events)
 static void sigterm_cb(uev_t *w, void *arg, int events)
 {
 	_d("...");
+	if (UEV_ERROR == events) {
+		_e("Unrecoverable error in signal watcher");
+		return;
+	}
+
 	halt = SHUT_REBOOT;
 	service_runlevel(6);
 }
@@ -275,6 +300,11 @@ static void sigchld_cb(uev_t *w, void *arg, int events)
 {
 	pid_t pid;
 
+	if (UEV_ERROR == events) {
+		_e("Unrecoverable error in signal watcher");
+		return;
+	}
+
 	/* Reap all the children! */
 	do {
 		pid = waitpid(-1, NULL, WNOHANG);
@@ -290,6 +320,11 @@ static void sigchld_cb(uev_t *w, void *arg, int events)
  */
 static void sigstop_cb(uev_t *w, void *arg, int events)
 {
+	if (UEV_ERROR == events) {
+		_e("Unrecoverable error in signal watcher");
+		return;
+	}
+
 	touch(SYNC_STOPPED);
 	stopped++;
 }
@@ -299,6 +334,11 @@ static void sigstop_cb(uev_t *w, void *arg, int events)
  */
 static void sigcont_cb(uev_t *w, void *arg, int events)
 {
+	if (UEV_ERROR == events) {
+		_e("Unrecoverable error in signal watcher");
+		return;
+	}
+
 	stopped = 0;
 	erase(SYNC_STOPPED);
 }