notify_email plugin: Check for "session == NULL" and return gracefully.

I don't know how libesmtp handles NULL pointers and I don't want to take
my chances.

diff --git a/src/notify_email.c b/src/notify_email.c
index 10d5ab1..0aed27f 100644 (file)
--- a/src/notify_email.c
+++ b/src/notify_email.c
@@ -272,6 +272,12 @@ static int notify_email_notification (const notification_t *n,
 
   pthread_mutex_lock (&session_lock);
 
+  if (session == NULL) {
+    /* Initialization failed or we're in the process of shutting down. */
+    pthread_mutex_unlock (&session_lock);
+    return (-1);
+  }
+
   if (!(message = smtp_add_message (session))) {
     pthread_mutex_unlock (&session_lock);
     ERROR ("notify_email plugin: cannot set SMTP message");