From 648ca49397e5c75241c6dc3c3ccce7239d604bf7 Mon Sep 17 00:00:00 2001
From: Stefan Schantl <stefan.schantl@ipfire.org>
Date: Wed, 17 Feb 2016 14:26:13 +0100
Subject: [PATCH] Add logrotate support.

Add the ability to get informed when the monitored files
have been rotated by logrotate and therefore the stored
file positions needs to be re-newed.

Signed-off-by: Stefan Schantl <stefan.schantl@ipfire.org>
---
 guardian          | 43 +++++++++++++++++++++++++++++++++++++++++++
 modules/Events.pm |  1 +
 2 files changed, 44 insertions(+)

diff --git a/guardian b/guardian
index 691ddc6..16d4198 100644
--- a/guardian
+++ b/guardian
@@ -403,6 +403,49 @@ sub Reload () {
 	&StartWorkers();
 }
 
+#
+## Logrotate function.
+#
+## This function only get called when the logrotate command will be sent via
+## the socket connection. It is responsible for validating and altering the current
+## curser positions of the monitored files and stopping/starting the worker threads.
+#
+sub Logrotate () {
+	# Stop all running workers.
+	&StopWorkers();
+
+	{
+	# Lock shared hash.
+	lock(%file_positions);
+
+	# Loop through the hash which contains the current
+	# file positions.
+	foreach my $file (keys(%file_positions)) {
+		# Obtain stored value from hash.
+		my $stored_position = $file_positions{$file};
+
+		# Call function to get the current position.
+		my $current_position = &Guardian::Base::GetFileposition($file);
+
+		# Compare if the current position still matches
+		# the stored one.
+		if ($current_position ne $stored_position) {
+			# Update to the new position, because
+			# they has changed during file rotation.
+			$file_positions{$file} = $current_position;
+
+			# Log notice about rotated file.
+			$logger->Log("debug", "$file have been rotated - Using new file position.");
+		}
+	}
+
+	# After this bracket, the lock of the hash will be released.
+	}
+
+	# Restart all worker threads.
+	&StartWorkers();
+}
+
 #
 ## Shutdown function.
 #
diff --git a/modules/Events.pm b/modules/Events.pm
index 025fe4f..2be2ac7 100644
--- a/modules/Events.pm
+++ b/modules/Events.pm
@@ -13,6 +13,7 @@ my %commands = (
 	'unblock' => \&CallUnblock,
 	'flush' => \&CallFlush,
 	'reload' => \&main::Reload,
+	'logrotate' => \&main::Logrotate,
 );
 
 # Hash to store addresses and their current count.
-- 
2.39.2