From 2b5d28ac59346523440d2b3977ea8b69d316d53f Mon Sep 17 00:00:00 2001
From: Daniel Baumann <daniel.baumann@open-infrastructure.net>
Date: Fri, 12 Apr 2019 21:22:40 +0200
Subject: Using trap function to unmount bind mounts etc. on exit with or
 without error.

Signed-off-by: Daniel Baumann <daniel.baumann@open-infrastructure.net>
---
 share/scripts/debconf | 228 +++++++++++++++++++++++++++-----------------------
 1 file changed, 123 insertions(+), 105 deletions(-)

diff --git a/share/scripts/debconf b/share/scripts/debconf
index 35b5969..b4b5e18 100755
--- a/share/scripts/debconf
+++ b/share/scripts/debconf
@@ -126,6 +126,124 @@ then
 	exit 1
 fi
 
+Start ()
+{
+	# Mounting rw bind mounts
+	if [ -n "${BIND}" ]
+	then
+		BINDS="$(echo ${BIND} | sed -e 's|;| |g')"
+
+		for ENTRY in ${BINDS}
+		do
+			SOURCE="$(echo ${ENTRY} | awk -F: '{ print $1 }')"
+			TARGET="$(echo ${ENTRY} | awk -F: '{ print $2 }')"
+
+			mkdir -p "${SOURCE}"
+			mkdir -p "${MACHINES}/${NAME}/${TARGET}"
+
+			mount -o bind "${SOURCE}" "${MACHINES}/${NAME}/${TARGET}"
+		done
+	fi
+
+	# Mounting ro bind mounts
+	if [ -n "${BIND_RO}" ]
+	then
+		BINDS_RO="$(echo ${BIND_RO} | sed -e 's|;| |g')"
+
+		for ENTRY in ${BINDS_RO}
+		do
+			SOURCE="$(echo ${ENTRY} | awk -F: '{ print $1 }')"
+			TARGET="$(echo ${ENTRY} | awk -F: '{ print $2 }')"
+
+			mkdir -p "${SOURCE}"
+			mkdir -p "${MACHINES}/${NAME}/${TARGET}"
+
+			mount -o rbind "${SOURCE}" "${MACHINES}/${NAME}/${TARGET}"
+		done
+	fi
+
+	# Mounting overlay mounts
+	if [ -n "${CNT_OVERLAY}" ]
+	then
+		CNT_OVERLAYS="$(echo ${CNT_OVERLAY} | sed -e 's|;| |g')"
+
+		for CNT_OVERLAY in ${CNT_OVERLAYS}
+		do
+			DIRECTORY_LOWER="$(echo ${CNT_OVERLAY} | awk -F: '{ print $1 }')"
+			DIRECTORY_UPPER="$(echo ${CNT_OVERLAY} | awk -F: '{ print $2 }')"
+			DIRECTORY_WORK="$(echo ${CNT_OVERLAY} | awk -F: '{ print $3 }')"
+			DIRECTORY_MERGED="$(echo ${CNT_OVERLAY} | awk -F: '{ print $4 }')"
+
+			for DIRECTORY in "${DIRECTORY_LOWER}" "${DIRECTORY_UPPER}" "${DIRECTORY_WORK}" "${DIRECTORY_MERGED}"
+			do
+				mkdir -p "${DIRECTORY}"
+			done
+
+			mount -t overlay overlay-${NAME} -olowerdir="${DIRECTORY_LOWER}",upperdir="${DIRECTORY_UPPER}",workdir="${DIRECTORY_WORK}" "${DIRECTORY_MERGED}"
+		done
+	fi
+
+	# Trap function
+	trap 'Stop' EXIT HUP INT QUIT TERM
+}
+
+Stop ()
+{
+	# Unmounting overlay mounts
+	if [ -n "${CNT_OVERLAY}" ]
+	then
+		CNT_OVERLAYS="$(echo ${CNT_OVERLAY} | sed -e 's|;| |g')"
+
+		for CNT_OVERLAY in ${CNT_OVERLAYS}
+		do
+			DIRECTORY_LOWER="$(echo ${CNT_OVERLAY} | awk -F: '{ print $1 }')"
+			DIRECTORY_UPPER="$(echo ${CNT_OVERLAY} | awk -F: '{ print $2 }')"
+			DIRECTORY_WORK="$(echo ${CNT_OVERLAY} | awk -F: '{ print $3 }')"
+			DIRECTORY_MERGED="$(echo ${CNT_OVERLAY} | awk -F: '{ print $4 }')"
+
+			umount -f "${DIRECTORY_MERGED}" > /dev/null 2>&1 || true
+
+			for DIRECTORY in "${DIRECTORY_LOWER}" "${DIRECTORY_UPPER}" "${DIRECTORY_WORK}" "${DIRECTORY_MERGED}"
+			do
+				rmdir --ignore-fail-on-non-empty --parents ${DIRECTORY} > /dev/null 2>&1 || true
+			done
+		done
+	fi
+
+	# Unmounting ro bind mounts
+	if [ -n "${BIND_RO}" ]
+	then
+		# unmount in reverse order to allow nested bind mounts
+		BINDS_RO="$(echo ${BIND_RO} | sed -e 's|;| |g' | awk '{ for (i=NF; i>=1; i--) printf "%s ", $i; print ""}')"
+
+		for ENTRY in ${BINDS_RO}
+		do
+			TARGET="$(echo ${ENTRY} | awk -F: '{ print $2 }')"
+
+			umount -f "${MACHINES}/${NAME}/${TARGET}" > /dev/null 2>&1 || true
+		done
+	fi
+
+	# Unmounting rw bind mounts
+	if [ -n "${BIND}" ]
+	then
+		# unmount in reverse order to allow nested bind mounts
+		BINDS="$(echo ${BIND} | sed -e 's|;| |g' | awk '{ for (i=NF; i>=1; i--) printf "%s ", $i; print ""}')"
+
+		for ENTRY in ${BINDS}
+		do
+			TARGET="$(echo ${ENTRY} | awk -F: '{ print $2 }')"
+
+			umount -f "${MACHINES}/${NAME}/${TARGET}" > /dev/null 2>&1 || true
+		done
+	fi
+
+	# Unmounting pseudo-filesystems
+	umount -f "${DIRECTORY}/dev/pts" > /dev/null 2>&1 || true
+	umount -f "${DIRECTORY}/proc" > /dev/null 2>&1 || true
+	umount -f "${DIRECTORY}/sys" > /dev/null 2>&1 || true
+}
+
 Chroot ()
 {
 	CHROOT="${1}"
@@ -187,9 +305,9 @@ Cleanup_system ()
 	rm -f "${DIRECTORY}/usr/sbin/policy-rc.d"
 
 	# Unmount pseudo-filesystems
-	umount "${DIRECTORY}/dev/pts"
-	umount "${DIRECTORY}/proc"
-	umount "${DIRECTORY}/sys"
+	umount -f "${DIRECTORY}/dev/pts" > /dev/null 2>&1 || true
+	umount -f "${DIRECTORY}/proc" > /dev/null 2>&1 || true
+	umount -f "${DIRECTORY}/sys" > /dev/null 2>&1 || true
 }
 
 Debconf ()
@@ -1011,60 +1129,7 @@ Cleanup_system "${CACHE}/${DISTRIBUTION}_${ARCHITECTURE}"
 mkdir -p "${MACHINES}"
 cp -a "${CACHE}/${DISTRIBUTION}_${ARCHITECTURE}" "${MACHINES}/${NAME}"
 
-# Mounting rw bind mounts
-if [ -n "${BIND}" ]
-then
-	BINDS="$(echo ${BIND} | sed -e 's|;| |g')"
-
-	for ENTRY in ${BINDS}
-	do
-		SOURCE="$(echo ${ENTRY} | awk -F: '{ print $1 }')"
-		TARGET="$(echo ${ENTRY} | awk -F: '{ print $2 }')"
-
-		mkdir -p "${SOURCE}"
-		mkdir -p "${MACHINES}/${NAME}/${TARGET}"
-
-		mount -o bind "${SOURCE}" "${MACHINES}/${NAME}/${TARGET}"
-	done
-fi
-
-# Mounting ro bind mounts
-if [ -n "${BIND_RO}" ]
-then
-	BINDS_RO="$(echo ${BIND_RO} | sed -e 's|;| |g')"
-
-	for ENTRY in ${BINDS_RO}
-	do
-		SOURCE="$(echo ${ENTRY} | awk -F: '{ print $1 }')"
-		TARGET="$(echo ${ENTRY} | awk -F: '{ print $2 }')"
-
-		mkdir -p "${SOURCE}"
-		mkdir -p "${MACHINES}/${NAME}/${TARGET}"
-
-		mount -o rbind "${SOURCE}" "${MACHINES}/${NAME}/${TARGET}"
-	done
-fi
-
-# Mounting overlay mounts
-if [ -n "${CNT_OVERLAY}" ]
-then
-	CNT_OVERLAYS="$(echo ${CNT_OVERLAY} | sed -e 's|;| |g')"
-
-	for CNT_OVERLAY in ${CNT_OVERLAYS}
-	do
-		DIRECTORY_LOWER="$(echo ${CNT_OVERLAY} | awk -F: '{ print $1 }')"
-		DIRECTORY_UPPER="$(echo ${CNT_OVERLAY} | awk -F: '{ print $2 }')"
-		DIRECTORY_WORK="$(echo ${CNT_OVERLAY} | awk -F: '{ print $3 }')"
-		DIRECTORY_MERGED="$(echo ${CNT_OVERLAY} | awk -F: '{ print $4 }')"
-
-		for DIRECTORY in "${DIRECTORY_LOWER}" "${DIRECTORY_UPPER}" "${DIRECTORY_WORK}" "${DIRECTORY_MERGED}"
-		do
-			mkdir -p "${DIRECTORY}"
-		done
-
-		mount -t overlay overlay-${NAME} -olowerdir="${DIRECTORY_LOWER}",upperdir="${DIRECTORY_UPPER}",workdir="${DIRECTORY_WORK}" "${DIRECTORY_MERGED}"
-	done
-fi
+Start
 
 Configure_system "${MACHINES}/${NAME}"
 Configure_network "${MACHINES}/${NAME}"
@@ -1073,54 +1138,7 @@ Cleanup_system "${MACHINES}/${NAME}"
 
 Commands "${MACHINES}/${NAME}"
 
-# Unmounting overlay mounts
-if [ -n "${CNT_OVERLAY}" ]
-then
-	CNT_OVERLAYS="$(echo ${CNT_OVERLAY} | sed -e 's|;| |g')"
-
-	for CNT_OVERLAY in ${CNT_OVERLAYS}
-	do
-		DIRECTORY_LOWER="$(echo ${CNT_OVERLAY} | awk -F: '{ print $1 }')"
-		DIRECTORY_UPPER="$(echo ${CNT_OVERLAY} | awk -F: '{ print $2 }')"
-		DIRECTORY_WORK="$(echo ${CNT_OVERLAY} | awk -F: '{ print $3 }')"
-		DIRECTORY_MERGED="$(echo ${CNT_OVERLAY} | awk -F: '{ print $4 }')"
-
-		umount -f "${DIRECTORY_MERGED}"
-
-		for DIRECTORY in "${DIRECTORY_LOWER}" "${DIRECTORY_UPPER}" "${DIRECTORY_WORK}" "${DIRECTORY_MERGED}"
-		do
-			rmdir --ignore-fail-on-non-empty --parents ${DIRECTORY} > /dev/null 2>&1 || true
-		done
-	done
-fi
-
-# Unmounting ro bind mounts
-if [ -n "${BIND_RO}" ]
-then
-	# unmount in reverse order to allow nested bind mounts
-	BINDS_RO="$(echo ${BIND_RO} | sed -e 's|;| |g' | awk '{ for (i=NF; i>=1; i--) printf "%s ", $i; print ""}')"
-
-	for ENTRY in ${BINDS_RO}
-	do
-		TARGET="$(echo ${ENTRY} | awk -F: '{ print $2 }')"
-
-		umount "${MACHINES}/${NAME}/${TARGET}"
-	done
-fi
-
-# Unmounting rw bind mounts
-if [ -n "${BIND}" ]
-then
-	# unmount in reverse order to allow nested bind mounts
-	BINDS="$(echo ${BIND} | sed -e 's|;| |g' | awk '{ for (i=NF; i>=1; i--) printf "%s ", $i; print ""}')"
-
-	for ENTRY in ${BINDS}
-	do
-		TARGET="$(echo ${ENTRY} | awk -F: '{ print $2 }')"
-
-		umount "${MACHINES}/${NAME}/${TARGET}"
-	done
-fi
+Stop
 
 # remove debconf temporary files
 rm --preserve-root --one-file-system -rf "${DEBCONF_TMPDIR}"
-- 
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