Avoid manual handling of loop devices

Cryptsetup is since 1.3.0 capable of setting up a loop device if the
device argument is a file.
This has the additional benefit that those loop devices will get the
AUTOCLEAR flag (available with Linux 2.6.25). This means those loop
devices will be closed as soon they're unused (on luksClose).

tomb

@@ -187,12 +187,10 @@ _endgame() {
 	done
 	unset TOMBTMPFILES
 
-	# Detach loop devices
+	# Clear information regarding loop devices
-	for l in $TOMBLOOPDEVS; do
+	# No need for an explicit detach as cryptsetup
-		_sudo losetup -d "$l"
+	# sets the AUTOCLEAR flag
-	done
 	unset TOMBLOOPDEVS
-
 }
 
 # Trap functions for the _endgame event
@@ -707,7 +705,7 @@ is_valid_tomb() {
 
 	# checks if Tomb already mounted (or we cannot alter it)
 	local maphash=`realpath $TOMBPATH | sha256sum`
-	lo_mount # fills TOMBLOOP with next loop
+	lo_check # fills TOMBLOOP with next loop if available
 	TOMBMAPPER="tomb.$TOMBNAME.${maphash[(w)1]}.`basename $TOMBLOOP`"
 	local mounted_tombs=(`list_tomb_mounts`)
 	local usedmapper
@@ -724,9 +722,8 @@ is_valid_tomb() {
 	return 0
 }
 
-
+# $1 is the tomb file which needs a loop device
-# $1 is the tomb file to be lomounted
+lo_check() {
-lo_mount() {
 	tpath="$1"
 
 	# check if we have support for loop mounting
@@ -740,25 +737,11 @@ lo_mount() {
 
 	[[ "$tpath" == "" ]] && return 0
 
-
-	# allocates the next loopback for our file
-	_sudo losetup -f "$tpath" || _failure "Loopback mount failed: ::1 path:: on ::2 loop::" "$tpath" $TOMBLOOP
-
 	TOMBLOOPDEVS+=("$TOMBLOOP") # add to array of lodevs used
 
 	return 0
 }
 
-# print out latest loopback mounted
-lo_new() { print - "${TOMBLOOPDEVS[${#TOMBLOOPDEVS}]}" }
-
-# $1 is the path to the lodev to be preserved after quit
-lo_preserve() {
-	_verbose "lo_preserve on ::1 path::" $1
-	# remove the lodev from the tomb_lodevs array
-	TOMBLOOPDEVS=("${(@)TOMBLOOPDEVS:#$1}")
-}
-
 # eventually used for debugging
 dump_secrets() {
 	print "TOMBPATH: $TOMBPATH"
@@ -2212,12 +2195,10 @@ lock_tomb_with_key() {
 		_success "Selected filesystem type $filesystem."
 	}
 
-	lo_mount "$TOMBPATH"
+	lo_check "$TOMBPATH"
-
-	_verbose "Loop mounted on ::1 mount point::" $TOMBLOOP
 
 	_message "Checking if the tomb is empty (we never step on somebody else's bones)."
-	_sudo cryptsetup isLuks ${TOMBLOOP}
+	_sudo cryptsetup isLuks ${TOMBPATH}
 	if [ $? = 0 ]; then
 		# is it a LUKS encrypted nest? then bail out and avoid reformatting it
 		_warning "The tomb was already locked with another key."
@@ -2248,12 +2229,12 @@ lock_tomb_with_key() {
 	_message "Formatting Luks mapped device."
 	_cryptsetup --batch-mode \
 				--cipher ${cipher} --hash sha512 --key-size 512 --key-slot 0 \
-				luksFormat ${TOMBLOOP}
+				luksFormat ${TOMBPATH}
 	[[ $? == 0 ]] || {
 		_warning "cryptsetup luksFormat returned an error."
 		_failure "Operation aborted." }
 
-	_cryptsetup --cipher ${cipher} --hash sha512 luksOpen ${TOMBLOOP} tomb.tmp
+	_cryptsetup --cipher ${cipher} --hash sha512 luksOpen ${TOMBPATH} tomb.tmp
 	[[ $? == 0 ]] || {
 		_warning "cryptsetup luksOpen returned an error."
 		_failure "Operation aborted." }
@@ -2306,10 +2287,8 @@ change_tomb_key() {
 	_check_swap
 
 	is_valid_tomb $tombpath
-
+	lo_check "$TOMBPATH"
-	lo_mount "$TOMBPATH"
+	_sudo cryptsetup isLuks ${TOMBPATH}
-
-	_sudo cryptsetup isLuks ${TOMBLOOP}
 	# is it a LUKS encrypted nest? we check one more time
 	[[ $? == 0 ]] || {
 		_failure "Not a valid LUKS encrypted volume: ::1 volume::" $TOMBPATH }
@@ -2339,7 +2318,7 @@ change_tomb_key() {
 
 	# luksOpen the tomb (not really mounting, just on the loopback)
 	print -R -n - "$old_secret" | _sudo cryptsetup --key-file - \
-										luksOpen ${TOMBLOOP} ${TOMBMAPPER}
+										luksOpen ${TOMBPATH} ${TOMBMAPPER}
 	[[ $? == 0 ]] || _failure "Unexpected error in luksOpen."
 
 	_load_key # Try loading new key from option -k and set TOMBKEYFILE
@@ -2361,7 +2340,7 @@ change_tomb_key() {
 	print -R -n - "$TOMBSECRET" >> $tmpnewkey
 
 	print -R -n - "$old_secret" | _sudo cryptsetup --key-file - \
-										luksChangeKey "$TOMBLOOP" "$tmpnewkey"
+										luksChangeKey "$TOMBPATH" "$tmpnewkey"
 
 	[[ $? == 0 ]] || _failure "Unexpected error in luksChangeKey."
 
@@ -2429,15 +2408,15 @@ mount_tomb() {
 			_failure "Mountpoint already in use: ::1 mount point::" "$tombmount"
 	done
 
-	lo_mount "$TOMBPATH"
 
-	_sudo cryptsetup isLuks ${TOMBLOOP} || {
+	lo_check "$TOMBPATH"
+	_sudo cryptsetup isLuks ${TOMBPATH} || {
 		# is it a LUKS encrypted nest? see cryptsetup(1)
 		_failure "::1 tomb file:: is not a valid Luks encrypted storage file." $TOMBFILE }
 
 	_message "This tomb is a valid LUKS encrypted device."
 
-	luksdump="`_sudo cryptsetup luksDump ${TOMBLOOP}`"
+	luksdump="`_sudo cryptsetup luksDump ${TOMBPATH}`"
 	tombdump=(`print $luksdump | awk '
 		/^Cipher name/ {print $3}
 		/^Cipher mode/ {print $3}
@@ -2465,13 +2444,10 @@ mount_tomb() {
 	}
 	[[ $? == 0 ]] || _failure "No valid password supplied."
 
-	_cryptsetup luksOpen ${TOMBLOOP} ${TOMBMAPPER}
+	_cryptsetup luksOpen ${TOMBPATH} ${TOMBMAPPER}
 	[[ $? = 0 ]] || {
 		_failure "Failure mounting the encrypted file." }
 
-	# preserve the loopdev after exit
-	lo_preserve "$TOMBLOOP"
-
 	# array: [ cipher, keysize, loopdevice ]
 	tombstat=(`_sudo cryptsetup status ${TOMBMAPPER} | awk '
 	/cipher:/  {print $2}
@@ -2482,7 +2458,7 @@ mount_tomb() {
 
 	filesystem=`_detect_filesystem /dev/mapper/${TOMBMAPPER}`
 	_message "Filesystem detected: ::1 filesystem::" $filesystem
-	# TODO: check if FS is supported, else close luks and loop
+	# TODO: check if FS is supported, else close luks
 
 	_verbose "Tomb engraved as ::1 tomb name::" $TOMBNAME
 
@@ -2525,7 +2501,6 @@ mount_tomb() {
 		# TODO: move cleanup to _endgame()
 		[[ -d "$tombmount" ]] && _sudo rmdir "$tombmount"
 		[[ -e /dev/mapper/$TOMBMAPPER ]] && _sudo cryptsetup luksClose $TOMBMAPPER
-		# The loop is taken care of in _endgame()
 		_failure "Cannot mount ::1 tomb name::" $TOMBNAME
 	}
 
@@ -2738,7 +2713,7 @@ awk "/mapper/"' { print $2 ";" $3 ";" $4 ";" $5 }'`
 		_message "::1 tombname:: open on ::2 tombmount:: using ::3 tombfsopts::" \
 				 $tombname "$tombmount" $tombfsopts
 
-		_verbose "::1 tombname:: /dev/::2 tombloop:: device mounted (detach with losetup -d)" $tombname $tombloop
+		_verbose "::1 tombname:: attached to /dev/::2 tombloop:: device" $tombname $tombloop
 
 		_message "::1 tombname:: open since ::2 tombsince::" $tombname $tombsince
 
@@ -3002,10 +2977,10 @@ resize_tomb() {
 		_failure "The new size must be greater then old tomb size."
 	fi
 
-	lo_mount "$TOMBPATH"
+	lo_check "$TOMBPATH"
 
 	_message "opening tomb"
-	_cryptsetup luksOpen ${TOMBLOOP} ${TOMBMAPPER} || {
+	_cryptsetup luksOpen ${TOMBPATH} ${TOMBMAPPER} || {
 		_failure "Failure mounting the encrypted file." }
 
 	_sudo cryptsetup resize "${TOMBMAPPER}" || {
@@ -3146,12 +3121,6 @@ umount_tomb() {
 		_sudo cryptsetup luksClose $mapper ||
 			_failure "Error occurred in cryptsetup luksClose ::1 mapper::" $mapper
 
-		# Normally the loopback device is detached when unused
-		[[ -e "/dev/$tombloop" ]] && {
-			_sudo losetup -d "/dev/$tombloop" ||
-				_verbose "/dev/$tombloop was already closed."
-		}
-
 		_success "Tomb ::1 tomb name:: closed: your bones will rest in peace." $tombname
 
 	done # loop across mounted tombs