From f80797de04edf5a185a166869f8ca1493794db4a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Dennis=20K=C3=B6rner?=
 <79668910+netzwergehh@users.noreply.github.com>
Date: Thu, 3 Jun 2021 12:25:32 +0200
Subject: [PATCH] Update mirrorsync.sh

Added dead process check to file locking
---
 mirrorsync.sh | 30 +++++++++++++++++++-----------
 1 file changed, 19 insertions(+), 11 deletions(-)

diff --git a/mirrorsync.sh b/mirrorsync.sh
index 51da284..65262f0 100644
--- a/mirrorsync.sh
+++ b/mirrorsync.sh
@@ -53,6 +53,8 @@ filelistfile="fullfiletimelist-rocky"
 lockfile="$0.lockfile"
 logfile="$0.log"
 
+# Check if the filelistfile has changed on upstream mirror
+# and exit if it is still the same
 checkresult=$(${rsync} --no-motd --dry-run --out-format="%n" "${src}/${filelistfile}" "${dst}/${filelistfile}")
 if [[ -z "$checkresult" ]]; then
 	printf "%s unchanged. Not updating at %(%c)T\n" "$filelistfile" -1 >> "$logfile" 2>&1
@@ -60,17 +62,23 @@ if [[ -z "$checkresult" ]]; then
 	exit 1
 fi
 
-
-if [[ -e "$lockfile" ]]; then
+# Check for existing lockfile to avoid multiple simultaneously running syncs
+# If lockfile exists but process is dead continue anyway
+if [[ -e "$lockfile" ]] && ! kill -0 "$(< "$lockfile")"; then
+	printf "Warning: lockfile exists but process dead, continuing.\n" >> "$logfile" 2>&1
+	logger -t rsync "Warning: lockfile exists but process dead, continuing with updating ${mirrormodule}."
+	rm -f "$lockfile"
+elif [[ -e "$lockfile" ]]; then
 	printf "Update already in progress at %(%c)T\n" -1 >> "$logfile" 2>&1
 	logger -t rsync "Not updating ${mirrormodule}: already in progress."
-else
-	touch $lockfile
-	printf "Started update at %(%c)T\n" -1 >> "$logfile" 2>&1
-	logger -t rsync "Updating ${mirrormodule}"
-		
-	${rsync} "${opts[@]}" "${src}/" "${dst}/" >> "$logfile" 2>&1
-	logger -t rsync "Finished updating ${mirrormodule}"  
-	printf "End: %(%c)T\n" -1 >> "$logfile" 2>&1
-	rm -f $lockfile
+	exit 1
 fi
+
+# The actual syncing part
+printf '%s\n' "$$" > "$lockfile"
+printf "Started update at %(%c)T\n" -1 >> "$logfile" 2>&1
+logger -t rsync "Updating ${mirrormodule}"
+${rsync} "${opts[@]}" "${src}/" "${dst}/" >> "$logfile" 2>&1
+logger -t rsync "Finished updating ${mirrormodule}"  
+printf "End: %(%c)T\n" -1 >> "$logfile" 2>&1
+rm -f $lockfile