Touch PID file on SIGHUP to ACK signal

When used with Finit a daemon is expected to acknowledge SIGHUP
by touching its PID file.  Finit can do this by itself, however,
but having native support for this in sysklgod is highly useful.

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

pidfile.c

@@ -118,6 +118,16 @@ int write_pid (char *pidfile)
   return pid;
 }
 
+/* touch_pid
+ *
+ * Touches the specified pidfile f.ex. when receiving a SIGHUP
+ * The result from utimensat() is returned
+ */
+int touch_pid (char *pidfile)
+{
+  return utimensat(0, pidfile, NULL, 0);
+}
+
 /* remove_pid
  *
  * Remove the the specified file. The result from unlink(2)

pidfile.h

@@ -42,6 +42,13 @@ int check_pid (char *pidfile);
  */
 int write_pid (char *pidfile);
 
+/* touch_pid
+ *
+ * Touches the specified pidfile f.ex. when receiving a SIGHUP
+ * The result from utimensat() is returned
+ */
+int touch_pid (char *pidfile);
+
 /* remove_pid
  *
  * Remove the the specified file. The result from unlink(2)

syslogd.c

@@ -1161,6 +1161,13 @@ int main(argc, argv)
 			restart = 0;
 			dprintf("\nReceived SIGHUP, reloading syslogd.\n");
 			init();
+			if (check_pid(PidFile)) {
+				if (touch_pid(PidFile))
+					logerror("Not possible to touch pidfile");
+			} else {
+				if (!write_pid(PidFile))
+					logerror("Failed to write pidfile");
+			}
 			continue;
 		}
 		if (nfds == 0) {