BUG#4276 - socket path too long

sql/mysqld.cc

@@ -1246,6 +1246,12 @@ static void server_init(void)
   {
     DBUG_PRINT("general",("UNIX Socket is %s",mysqld_unix_port));
 
+    if (strlen(mysqld_unix_port) > (sizeof(UNIXaddr.sun_path) - 1))
+    {
+      sql_print_error("The socket file path is too long (> %d): %s",
+                    sizeof(UNIXaddr.sun_path) - 1, mysqld_unix_port);
+      unireg_abort(1);
+    }
     if ((unix_sock= socket(AF_UNIX, SOCK_STREAM, 0)) < 0)
     {
       sql_perror("Can't start server : UNIX Socket "); /* purecov: inspected */