From 1021f3f33d607b689a1050db0e0f1111751bf75c Mon Sep 17 00:00:00 2001
From: "Kyle J. McKay" <mackyle@gmail.com>
Date: Wed, 10 Jun 2020 11:45:58 -0700
Subject: [PATCH] gc.sh: refactor lock_gc function for reuse

Split the `lock_gc` function into two parts:

 1) a new `v_lock_gc` function that always returns
    and is reusable

 2) a minimal `lock_gc` function that calls the new
    function and provides behavior identical to
    the previous incarnation of the `lock_gc` function

Signed-off-by: Kyle J. McKay <mackyle@gmail.com>
---
 jobd/gc.sh | 61 +++++++++++++++++++++++++++++++++++++++----------------------
 1 file changed, 39 insertions(+), 22 deletions(-)

diff --git a/jobd/gc.sh b/jobd/gc.sh
index f7694bd..bb3de2d 100755
--- a/jobd/gc.sh
+++ b/jobd/gc.sh
@@ -367,39 +367,56 @@ pack_is_complete() {
 }
 
 # On return a "$lockf" will have been created that must be removed when gc is done
-lock_gc() {
+# Create a gc.pid lockfile
+# $1 => name of variable to store result in
+# On success:
+#   variable named by $1 will contain the name of the newly create lockfile (i.e. "gc.pid")
+# On failure:
+#   variable named by $1 will contain the failure reason
+v_lock_gc() {
 	# be compatibile with gc.pid file from newer Git releases
-	lockf=gc.pid
-	hn="$(hostname)"
-	active=
-	if [ "$(createlock "$lockf")" ]; then
-		# If $lockf is:
+	_lockf='gc.pid'
+	_hn="$(hostname)"
+	_active=
+	if [ "$(createlock "$_lockf")" ]; then
+		# If $_lockf is:
 		#   1) less than 12 hours old
 		#   2) contains two fields (pid hostname) NO trailing NL
 		#   3) the hostname is different OR the pid is still alive
 		# then we exit as another active process is holding the lock
-		if [ "$(find -L "$lockf" -maxdepth 1 -mmin -720 -print 2>/dev/null)" ]; then
-			apid=
-			ahost=
-			read -r apid ahost ajunk <"$lockf" || :
-			if [ "$apid" ] && [ "$ahost" ]; then
-				if [ "$ahost" != "$hn" ] || pidactive "$apid"; then
-					active=1
+		if [ "$(find -L "$_lockf" -maxdepth 1 -mmin -720 -print 2>/dev/null)" ]; then
+			_apid=
+			_ahost=
+			read -r _apid _ahost _ajunk <"$_lockf" || :
+			if [ "$_apid" ] && [ "$_ahost" ]; then
+				if [ "$_ahost" != "$_hn" ] || pidactive "$_apid"; then
+					_active=1
 				fi
 			fi
 		fi
 	else
-		echo >&2 "[$proj] unable to create gc.pid.lock file"
-		exit 1
+		eval "$1="'"unable to create $_lockf.lock file"'
+		return 1
 	fi
-	if [ -n "$active" ]; then
-		rm -f "$lockf.lock"
-		echo >&2 "[$proj] gc already running on machine '$ahost' pid '$apid'"
-		exit 1
+	if [ -n "$_active" ]; then
+		rm -f "$_lockf.lock"
+		eval "$1="'"gc already running on machine '\''$_ahost'\'' pid '\''$_apid'\''"'
+		return 1
 	fi
-	printf "%s %s" "$$" "$hn" >"$lockf.lock"
-	chmod 0664 "$lockf.lock"
-	mv -f "$lockf.lock" "$lockf"
+	printf "%s %s" "$$" "$_hn" >"$_lockf.lock"
+	chmod 0664 "$_lockf.lock"
+	mv -f "$_lockf.lock" "$_lockf"
+	eval "$1="'"$_lockf"'
+	return 0
+}
+
+# On return a "$lockf" will have been created that must be removed when gc is done
+lock_gc() {
+	v_lock_gc _lockresult || {
+		echo >&2 "[$proj] $_lockresult"
+		exit 1
+	}
+	lockf="$_lockresult"
 }
 
 # Create a repack subdirectory such that running repack in it will pack the
-- 
2.11.4.GIT