From a09150a061203c3439f2c30ef6ce3cce7ac51c9e Mon Sep 17 00:00:00 2001
From: Joachim Nilsson <troglobit@gmail.com>
Date: Thu, 2 Aug 2018 15:37:02 +0200
Subject: [PATCH] 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 | 10 ++++++++++
 pidfile.h |  7 +++++++
 syslogd.c |  7 +++++++
 3 files changed, 24 insertions(+)

diff --git a/pidfile.c b/pidfile.c
index e0959a0..cf53b49 100644
--- a/pidfile.c
+++ b/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)
diff --git a/pidfile.h b/pidfile.h
index 19d19c1..8f1e490 100644
--- a/pidfile.h
+++ b/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)
diff --git a/syslogd.c b/syslogd.c
index a176371..8553f15 100644
--- a/syslogd.c
+++ b/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) {