[arch-projects] [RFC 14/23] Add support to ct_map for key devices

[Matthew Monaco]

From: Matthew Monaco <matthew.monaco at 0x01b.net>

The key field may be device:key:fstype or device:key in which case the
device is resolved and mounted if necessary. For these, key must be
relative to the root of the filesystem on the device.

The keydevice is mounted to $(mktemp -d). It is only unmounted if we
mounted it.
---
 cryptmount.sh |   76 +++++++++++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 74 insertions(+), 2 deletions(-)

diff --git a/cryptmount.sh b/cryptmount.sh
index 03699d0..a8a0ec8 100755
--- a/cryptmount.sh
+++ b/cryptmount.sh
@@ -341,8 +341,8 @@ ct_unmap() {
 
 ct_map() {
 
-<<<<<<< HEAD
 	local name="$1" dev="$2" key="$3" args="" swap=0
+	local key_dev="" key_fstype="" key_mntpnt="" key_dev_umount=0
 	shift 3
 
 	if [ -e "/dev/mapper/$name" ]; then
@@ -363,8 +363,71 @@ ct_map() {
 		return 1
 	fi
 
+	# parse various key formats
+	case "$key" in
+		*:*:*)
+			key_dev="${key%%:*}"
+			key="${key#*:}"
+			key_fstype="${key%%:*}"
+			key="${key#*:}"
+			;;
+		*:*)
+			key_dev="${key%%:*}"
+			key="${key#*:}"
+			;;
+		""|-)
+			unset key_dev
+			unset key
+			;;
+		*)
+			unset key_dev
+			;;
+	esac
+
+	# resolve any needed key device and mount if necessary
+	if [ "$key_dev" ]; then
+
+		if key_dev="$(ct_resolve_device "$key_dev")"; then
+
+			if key_mntpnt="$(findmnt -cfmnoTARGET "$key_dev")"; then
+
+				key="$key_mntpnt/$key"
+
+			elif key_mntpnt="$(mktemp -d)"; then
+
+				[ -n "$key_fstype" ] && key_fstype="-t $key_fstype"
+
+				if run mount -r $key_fstype "$key_dev" "$key_mntpnt"; then
+					key="$key_mntpnt/$key"
+					key_dev_umount=1
+				else
+					error "unable to mount key device '$key_dev',"
+					error " falling back on interactive password"
+					unset key
+				fi
+			else
+				error "unable to find or create mountpoint for key device,"
+				error " falling back on interactive password"
+				unset key
+			fi
+		else
+			error "key device '$key_dev' not found"
+			error " falling back on interactive password"
+			unset key
+		fi
+
+	elif [ -n "$key" -a "$key" != "-" ]; then
+
+		if ! key="$(ct_resolve_device "$key")"; then
+			error "key '$key' not found"
+			error " falling back on interactive password"
+			unset key
+		fi
+
+	fi
+
 	if [ "$key" ]; then
-		key="--key-file=\"$key\""
+		key=--key-file="$key"
 	fi
 
 	local ret=0
@@ -409,6 +472,15 @@ ct_map() {
 
 	fi
 
+	# clean up after ourselves
+	if [ $key_dev_umount -eq 1 ]; then
+		if ! run umount "$key_dev"; then
+			warn "unable to mount key device '$key_dev'"
+		else
+			run rmdir "$key_mntpnt"
+		fi
+	fi
+
 	return $ret
 }
 
-- 
1.7.10.2