initrd.scripts: improve readability of rootdev_init

defaults/initrd.scripts

@@ -1555,8 +1555,8 @@ rootdev_init() {
     while true
     do
         local got_good_root=
-        while [ "${got_good_root}" != '1' ]
-        do
+        while [ "${got_good_root}" != "1" ]; do
+
             case "${REAL_ROOT}" in
                 LABEL=*|UUID=*)
 
@@ -1571,18 +1571,19 @@ rootdev_init() {
                         continue
                     fi
                     ;;
+
                 # move this cruft into a separate function? do we really need
                 # the crazy root=ZFS= thing? can't we just detect the fstype?
                 ZFS*)
-                    if [ "${USE_ZFS}" = '0' ]; then
+                    if [ "${USE_ZFS}" = "0" ]; then
                         prompt_user "REAL_ROOT" "root block device"
                         continue
                     fi
+
                     ROOT_DEV="${REAL_ROOT#*=}"
-                    if [ "${ROOT_DEV}" != 'ZFS' ]
-                    then
-                        if [ "$(zfs get type -o value -H ${ROOT_DEV})" = 'filesystem' ]
-                        then
+                    if [ "${ROOT_DEV}" != "ZFS" ]; then
+                        local ztype=$(zfs get type -o value -H "${ROOT_DEV}")
+                        if [ "${ztype}" = "filesystem" ]; then
                             got_good_root=1;
                             REAL_ROOT=${ROOT_DEV}
                             ROOTFSTYPE=zfs
@@ -1594,12 +1595,9 @@ rootdev_init() {
                         fi
                     else
                         BOOTFS=$(/sbin/zpool list -H -o bootfs)
-                        if [ "${BOOTFS}" != '-' ]
-                        then
-
-                            for i in ${BOOTFS}
-                            do
+                        if [ "${BOOTFS}" != "-" ]; then
 
+                            for i in ${BOOTFS}; do
                                 zfs get type ${i} > /dev/null
                                 retval=$?
 
@@ -1624,19 +1622,17 @@ rootdev_init() {
                     ;;
             esac
 
-            if [ "${REAL_ROOT}" = '' ]
-            then
-                # No REAL_ROOT determined/specified. Prompt user for root block device.
+            if [ -z "${REAL_ROOT}" ]; then
+                # No REAL_ROOT determined/specified.
+                # Prompt user for root block device.
                 prompt_user "REAL_ROOT" "root block device"
                 got_good_root=0
 
             # Check for a block device or NFS
-            elif [ -b "${REAL_ROOT}" ] || is_nfs
-            then
+            elif [ -b "${REAL_ROOT}" ] || is_nfs; then
                 got_good_root=1
-
             else
-                bad_msg "Block device ${REAL_ROOT} is not a valid root device..."
+                bad_msg "${REAL_ROOT} is an invalid root device..."
                 REAL_ROOT=""
                 got_good_root=0
             fi
@@ -1654,22 +1650,22 @@ rootdev_init() {
         fi
 
         local fstype=$(get_device_fstype "${REAL_ROOT}")
-        good_msg "Initializing ${REAL_ROOT} if needed, detected fstype: ${fstype}"
+        good_msg "Initializing ${REAL_ROOT} if needed"
+        good_msg "Detected fstype: ${fstype}"
         fstype_init "${fstype}"
 
         good_msg "Mounting ${REAL_ROOT} as root..."
-
-        # TODO(lxnay): determine if it's possible to move this crufty thing into fstype_init
-        if [ "${ROOTFSTYPE}" = 'zfs' ]
-        then
-            if [ "$(zfs get -H -o value mountpoint ${REAL_ROOT})" = 'legacy' ]
-            then
-                MOUNT_STATE=rw
+        local mount_state=ro
+
+        # TODO(lxnay): determine if it's possible to move this
+        #              crufty thing into fstype_init
+        if [ "${ROOTFSTYPE}" = "zfs" ]; then
+            local zmtype=$(zfs get -H -o value mountpoint "${REAL_ROOT}")
+            if [ "${zmtype}" = "legacy" ]; then
+                mount_state=rw
             else
-                MOUNT_STATE=rw,zfsutil
+                mount_state=rw,zfsutil
             fi
-        else
-            MOUNT_STATE=ro
         fi
 
         # Try to mount the device as ${NEW_ROOT}
@@ -1677,19 +1673,18 @@ rootdev_init() {
             find_nfs  # sets ${?} checked below
         else
             # mount ro so fsck doesn't barf later
-            if [ "${REAL_ROOTFLAGS}" = '' ]; then
-                good_msg "Using mount -t ${ROOTFSTYPE} -o ${MOUNT_STATE}"
-                mount -t ${ROOTFSTYPE} -o ${MOUNT_STATE} ${REAL_ROOT} ${NEW_ROOT}
-            else
-                good_msg "Using mount -t ${ROOTFSTYPE} -o ${MOUNT_STATE},${REAL_ROOTFLAGS}"
-                mount -t ${ROOTFSTYPE} -o ${MOUNT_STATE},${REAL_ROOTFLAGS} ${REAL_ROOT} ${NEW_ROOT}
-            fi
+            local mopts="${mount_state}"
+            [ -n "${REAL_ROOTFLAGS}" ] && \
+                mopts="${mopts},${REAL_ROOTFLAGS}"
+
+            good_msg "Using mount -t ${ROOTFSTYPE} -o ${mopts}"
+            mount -t "${ROOTFSTYPE}" -o "${mopts}" \
+                "${REAL_ROOT}" "${NEW_ROOT}"
         fi
 
         # If mount is successful break out of the loop
         # else not a good root and start over.
-        if [ "$?" = '0' ]
-        then
+        if [ "${?}" = "0" ]; then
             # now that the root filesystem is mounted, before
             # checking the validity of ${NEW_ROOT} and ${REAL_INIT},
             # ensure that ${NEW_ROOT}/etc/initramfs.mounts entries