Refactor find_persistent_media().
[live-boot-grml.git] / scripts / live-helpers
index b812979..9dc1242 100644 (file)
@@ -15,6 +15,400 @@ else
        udevinfo='udevinfo'
 fi
 
+root_overlay_label="full-ov"
+custom_overlay_label="custom-ov"
+root_snapshot_label="live-sn"
+home_snapshot_label="home-sn"
+persistence_list="live.persist"
+
+Arguments ()
+{
+       PRESEEDS=""
+       LOCATIONS=""
+
+       for ARGUMENT in $(cat /proc/cmdline)
+       do
+               case "${ARGUMENT}" in
+                       skipconfig)
+                               NOACCESSIBILITY="Yes"
+                               NOFASTBOOT="Yes"
+                               NOFSTAB="Yes"
+                               NONETWORKING="Yes"
+
+                               export NOACCESSIBILITY NOFASTBOOT NOFSTAB NONETWORKING
+                               ;;
+
+                       access=*)
+                               ACCESS="${ARGUMENT#access=}"
+                               export ACCESS
+                               ;;
+
+                       console=*)
+                               DEFCONSOLE="${ARGUMENT#*=}"
+                               export DEFCONSOLE
+                               ;;
+
+                       BOOTIF=*)
+                               BOOTIF="${x#BOOTIF=}"
+                               ;;
+
+                       debug)
+                               DEBUG="Yes"
+                               export DEBUG
+
+                               set -x
+                               ;;
+
+                       dhcp)
+                               # Force dhcp even while netbooting
+                               # Use for debugging in case somebody works on fixing dhclient
+                               DHCP="Force";
+                               export DHCP
+                               ;;
+
+                       nodhcp)
+                               unset DHCP
+                               ;;
+
+                       ethdevice=*)
+                               DEVICE="${ARGUMENT#ethdevice=}"
+                               ETHDEVICE="${DEVICE}"
+                               export DEVICE ETHDEVICE
+                               ;;
+
+                       ethdevice-timeout=*)
+                               ETHDEV_TIMEOUT="${ARGUMENT#ethdevice-timeout=}"
+                               export ETHDEV_TIMEOUT
+                               ;;
+
+                       fetch=*)
+                               FETCH="${ARGUMENT#fetch=}"
+                               export FETCH
+                               ;;
+
+                       forcepersistentfsck)
+                               FORCEPERSISTENTFSCK="Yes"
+                               export FORCEPERSISTENTFSCK
+                               ;;
+
+                       ftpfs=*)
+                               FTPFS="${ARGUMENT#ftpfs=}"
+                               export FTPFS
+                               ;;
+
+                       httpfs=*)
+                               HTTPFS="${ARGUMENT#httpfs=}"
+                               export HTTPFS
+                               ;;
+
+                       iscsi=*)
+                               ISCSI="${ARGUMENT#iscsi=}"
+                               #ip:port - separated by ;
+                               ISCSI_PORTAL="${ISCSI%;*}"
+                               if echo "${ISCSI_PORTAL}" | grep -q , ; then
+                                       ISCSI_SERVER="${ISCSI_PORTAL%,*}"
+                                       ISCSI_PORT="${ISCSI_PORTAL#*,}"
+                               fi
+                               #target name
+                               ISCSI_TARGET="${ISCSI#*;}"
+                               export ISCSI ISCSI_PORTAL ISCSI_TARGET ISCSI_SERVER ISCSI_PORT
+                               ;;
+
+                       isofrom=*|fromiso=*)
+                               FROMISO="${ARGUMENT#*=}"
+                               export FROMISO
+                               ;;
+
+                       ignore_uuid)
+                               IGNORE_UUID="Yes"
+                               export IGNORE_UUID
+                               ;;
+
+                       integrity-check)
+                               INTEGRITY_CHECK="Yes"
+                               export INTEGRITY_CHECK
+                               ;;
+
+                       ip=*)
+                               STATICIP="${ARGUMENT#ip=}"
+
+                               if [ -z "${STATICIP}" ]
+                               then
+                                       STATICIP="frommedia"
+                               fi
+
+                               export STATICIP
+                               ;;
+
+                       live-getty)
+                               LIVE_GETTY="1"
+                               export LIVE_GETTY
+                               ;;
+
+                       live-media=*|bootfrom=*)
+                               LIVE_MEDIA="${ARGUMENT#*=}"
+                               export LIVE_MEDIA
+                               ;;
+
+                       live-media-encryption=*|encryption=*)
+                               LIVE_MEDIA_ENCRYPTION="${ARGUMENT#*=}"
+                               export LIVE_MEDIA_ENCRYPTION
+                               ;;
+
+                       live-media-offset=*)
+                               LIVE_MEDIA_OFFSET="${ARGUMENT#live-media-offset=}"
+                               export LIVE_MEDIA_OFFSET
+                               ;;
+
+                       live-media-path=*)
+                               LIVE_MEDIA_PATH="${ARGUMENT#live-media-path=}"
+                               export LIVE_MEDIA_PATH
+                               ;;
+
+                       live-media-timeout=*)
+                               LIVE_MEDIA_TIMEOUT="${ARGUMENT#live-media-timeout=}"
+                               export LIVE_MEDIA_TIMEOUT
+                               ;;
+
+                       module=*)
+                               MODULE="${ARGUMENT#module=}"
+                               export MODULE
+                               ;;
+
+                       netboot=*)
+                               NETBOOT="${ARGUMENT#netboot=}"
+                               export NETBOOT
+                               ;;
+
+                       nfsopts=*)
+                               NFSOPTS="${ARGUMENT#nfsopts=}"
+                               export NFSOPTS
+                               ;;
+
+                       nfscow=*)
+                               NFS_COW="${ARGUMENT#nfscow=}"
+                               export NFS_COW
+                               ;;
+
+                       noaccessibility)
+                               NOACCESSIBILITY="Yes"
+                               export NOACCESSIBILITY
+                               ;;
+
+                       nofastboot)
+                               NOFASTBOOT="Yes"
+                               export NOFASTBOOT
+                               ;;
+
+                       nofstab)
+                               NOFSTAB="Yes"
+                               export NOFSTAB
+                               ;;
+
+                       nonetworking)
+                               NONETWORKING="Yes"
+                               export NONETWORKING
+                               ;;
+
+                       ramdisk-size=*)
+                               ramdisk_size="${ARGUMENT#ramdisk-size=}"
+                               ;;
+
+                       swapon)
+                               SWAPON="Yes"
+                               export SWAPON
+                               ;;
+
+                       persistent)
+                               PERSISTENT="Yes"
+                               export PERSISTENT
+                               ;;
+
+                       persistent-encryption=*)
+                               PERSISTENT_ENCRYPTION="${ARGUMENT#*=}"
+                               export PERSISTENT_ENCRYPTION
+                               ;;
+
+                       persistent-media=*)
+                               PERSISTENT_MEDIA="${ARGUMENT#*=}"
+                               export PERSISTENT_MEDIA
+                               ;;
+                       persistent-method=*)
+                               PERSISTENT_METHOD="${ARGUMENT#*=}"
+                               export PERSISTENT_METHOD
+                               ;;
+
+                       persistent-path=*)
+                               PERSISTENT_PATH="${ARGUMENT#persistent-path=}"
+                               export PERSISTENT_PATH
+                               ;;
+                       persistent-read-only)
+                               PERSISTENT_READONLY="Yes"
+                               export PERSISTENT_READONLY
+                               ;;
+
+                       persistent-storage=*)
+                               PERSISTENT_STORAGE="${ARGUMENT#persistent-storage=}"
+                               export PERSISTENT_STORAGE
+                               ;;
+
+                       persistent-subtext=*)
+                               root_overlay_label="${root_overlay_label}-${ARGUMENT#persistent-subtext=}"
+                               custom_overlay_label="${custom_overlay_label}-${ARGUMENT#persistent-subtext=}"
+                               root_snapshot_label="${root_snapshot_label}-${ARGUMENT#persistent-subtext=}"
+                               home_snapshot_label="${home_snapshot_label}-${ARGUMENT#persistent-subtext=}"
+                               ;;
+
+                       nopersistent)
+                               NOPERSISTENT="Yes"
+                               export NOPERSISTENT
+                               ;;
+
+                       noprompt)
+                               NOPROMPT="Yes"
+                               export NOPROMPT
+                               ;;
+
+                       noprompt=*)
+                               NOPROMPT="${ARGUMENT#noprompt=}"
+                               export NOPROMPT
+                               ;;
+
+                       quickusbmodules)
+                               QUICKUSBMODULES="Yes"
+                               export QUICKUSBMODULES
+                               ;;
+
+                       preseed/file=*|file=*)
+                               LOCATIONS="${ARGUMENT#*=} ${LOCATIONS}"
+                               export LOCATIONS
+                               ;;
+
+                       nopreseed)
+                               NOPRESEED="Yes"
+                               export NOPRESEED
+                               ;;
+
+                       */*=*)
+                               question="${ARGUMENT%%=*}"
+                               value="${ARGUMENT#*=}"
+                               PRESEEDS="${PRESEEDS}\"${question}=${value}\" "
+                               export PRESEEDS
+                               ;;
+
+                       showmounts)
+                               SHOWMOUNTS="Yes"
+                               export SHOWMOUNTS
+                               ;;
+
+                       silent)
+                               SILENT="Yes"
+                               export SILENT
+                               ;;
+
+                       todisk=*)
+                               TODISK="${ARGUMENT#todisk=}"
+                               export TODISK
+                               ;;
+
+                       toram)
+                               TORAM="Yes"
+                               export TORAM
+                               ;;
+
+                       toram=*)
+                               TORAM="Yes"
+                               MODULETORAM="${ARGUMENT#toram=}"
+                               export TORAM MODULETORAM
+                               ;;
+
+                       exposedroot)
+                               EXPOSED_ROOT="Yes"
+                               export EXPOSED_ROOT
+                               ;;
+
+                       plainroot)
+                               PLAIN_ROOT="Yes"
+                               export PLAIN_ROOT
+                               ;;
+
+                       skipunion)
+                               SKIP_UNION_MOUNTS="Yes"
+                               export SKIP_UNION_MOUNTS
+                               ;;
+
+                       root=*)
+                               ROOT="${ARGUMENT#root=}"
+                               export ROOT
+                               ;;
+
+                       union=*)
+                               UNIONTYPE="${ARGUMENT#union=}"
+                               export UNIONTYPE
+                               ;;
+               esac
+       done
+
+       # sort of compatibility with netboot.h from linux docs
+       if [ -z "${NETBOOT}" ]
+       then
+               if [ "${ROOT}" = "/dev/nfs" ]
+               then
+                       NETBOOT="nfs"
+                       export NETBOOT
+               elif [ "${ROOT}" = "/dev/cifs" ]
+               then
+                       NETBOOT="cifs"
+                       export NETBOOT
+               fi
+       fi
+
+       if [ -z "${MODULE}" ]
+       then
+               MODULE="filesystem"
+               export MODULE
+       fi
+
+       if [ -z "${UNIONTYPE}" ]
+       then
+               UNIONTYPE="aufs"
+               export UNIONTYPE
+       fi
+
+       if [ -z "${PERSISTENT_ENCRYPTION}" ]
+       then
+               PERSISTENT_ENCRYPTION="none"
+               export PERSISTENT_ENCRYPTION
+       elif echo ${PERSISTENT_ENCRYPTION} | grep -qe "\<luks\>"
+       then
+               if ! modprobe dm-crypt
+               then
+                       log_warning_msg "Unable to load module dm-crypt"
+                       PERSISTENT_ENCRYPTION=$(echo ${PERSISTENT_ENCRYPTION} | sed -e 's/\<luks,\|,\?luks$//g')
+                       export PERSISTENT_ENCRYPTION
+               fi
+
+               if [ ! -x /lib/cryptsetup/askpass ] || [ ! -x /sbin/cryptsetup ]
+               then
+                       log_warning_msg "cryptsetup in unavailable"
+                       PERSISTENT_ENCRYPTION=$(echo ${PERSISTENT_ENCRYPTION} | sed -e 's/\<luks,\|,\?luks$//g')
+                       export PERSISTENT_ENCRYPTION
+               fi
+       fi
+
+       if [ -z "${PERSISTENT_METHOD}" ]
+       then
+               PERSISTENT_METHOD="snapshot,overlay"
+               export PERSISTENT_METHOD
+       fi
+
+       if [ -z "${PERSISTENT_STORAGE}" ]
+       then
+               PERSISTENT_STORAGE="filesystem,file"
+               export PERSISTENT_STORAGE
+       fi
+}
+
 sys2dev ()
 {
        sysdev=${1#/sys}
@@ -46,9 +440,9 @@ storage_devices()
        do
                fulldevname=$(sys2dev "${sysblock}")
 
-               if echo "${black_listed_devices}" | grep -qw "${fulldevname}" || \
+               if echo "${black_listed_devices}" | grep -qe "\<${fulldevname}\>" || \
                        [ -n "${white_listed_devices}" ] && \
-                       echo "${white_listed_devices}" | grep -vqw "${fulldevname}"
+                       echo "${white_listed_devices}" | grep -qve "\<${fulldevname}\>"
                then
                        # skip this device entirely
                        continue
@@ -58,7 +452,7 @@ storage_devices()
                do
                        devname=$(sys2dev "${dev}")
 
-                       if echo "${black_listed_devices}" | grep -qw "${devname}"
+                       if echo "${black_listed_devices}" | grep -qe "\<${devname}\>"
                        then
                                # skip this subdevice
                                continue
@@ -234,7 +628,7 @@ setup_loop ()
                                fi
                        fi
 
-                       if [ 0 -lt "${offset}" ]
+                       if [ -n "${offset}" ] && [ 0 -lt "${offset}" ]
                        then
                                options="${options} -o ${offset}"
                        fi
@@ -311,6 +705,96 @@ try_mount ()
        fi
 }
 
+open_luks_device ()
+{
+       dev="${1}"
+       name="$(basename ${dev})"
+       opts="--key-file=-"
+       if [ -n "${PERSISTENT_READONLY}" ]
+       then
+               opts="${opts} --readonly"
+       fi
+
+       load_keymap
+
+       while true
+       do
+               /lib/cryptsetup/askpass "Enter passphrase for ${dev}: " | \
+                       /sbin/cryptsetup -T 1 luksOpen ${dev} ${name} ${opts}
+
+               if [ 0 -eq ${?} ]
+               then
+                       luks_device="/dev/mapper/${name}"
+                       echo ${luks_device}
+                       return 0
+               fi
+
+               echo >&6
+               echo -n "There was an error decrypting ${dev} ... Retry? [Y/n] " >&6
+               read answer
+
+               if [ "$(echo "${answer}" | cut -b1 | tr A-Z a-z)" = "n" ]
+               then
+                       return 2
+               fi
+       done
+}
+
+probe_for_fs_label () {
+       local overlays="${1}"
+       local snapshots="${2}"
+       local dev="${3}"
+
+       for label in ${overlays} ${snapshots}
+       do
+               if [ "$(/sbin/blkid -s LABEL -o value $dev 2>/dev/null)" = "${label}" ]
+               then
+                       echo "${label}=${dev}"
+               fi
+       done
+}
+
+probe_for_file_name () {
+       local overlays="${1}"
+       local snapshots="${2}"
+       local dev="${3}"
+
+       local devfstype="$(get_fstype ${dev})"
+       local backing="${rootmnt}/live/persistent/$(basename ${dev})"
+       local ret=""
+       if is_supported_fs ${devfstype} && mkdir -p "${backing}" && \
+          try_mount "${dev}" "${backing}" "rw" "${devfstype}"
+       then
+               for label in ${overlays}
+               do
+                       path=${backing}/${PERSISTENT_PATH}${label}
+                       if [ -f "${path}" ]
+                       then
+                               local loopdev=$(setup_loop "${path}" "loop" "/sys/block/loop*")
+                               ret="${ret} ${label}=${loopdev}"
+                       fi
+               done
+               for label in ${snapshots}
+               do
+                       for ext in squashfs cpio.gz ext2 ext3 ext4 jffs2
+                       do
+                               path="${PERSISTENT_PATH}${label}.${ext}"
+                               if [ -f "${backing}/${path}" ]
+                               then
+                                       ret="${ret} ${label}=${dev}:${backing}:${path}"
+                               fi
+                       done
+               done
+
+               if [ -n "${ret}" ]
+               then
+                       echo ${ret}
+               else
+                       umount ${backing} > /dev/null 2>&1 || true
+               fi
+       fi
+}
+
 find_persistent_media ()
 {
        # Scans devices for overlays and snapshots, and returns a whitespace
@@ -338,115 +822,63 @@ find_persistent_media ()
        snapshots="${2}"
        black_listed_devices="${3}"
        white_listed_devices="${4}"
+       persistent_backing="${rootmnt}/live/persistent"
 
        for dev in $(storage_devices "${black_listed_devices}" "${white_listed_devices}")
        do
                luks_device=""
 
                # Checking for a luks device
-               if [ "${PERSISTENT_ENCRYPTION}" = "luks" ] && [ -e /sbin/cryptsetup ]
+               if echo ${PERSISTENT_ENCRYPTION} | grep -qe "\<luks\>" && \
+                  /sbin/cryptsetup isLuks ${dev}
                then
-                       if ! modprobe dm-crypt
+                       if luks_device=$(open_luks_device "${dev}")
                        then
-                               log_warning_msg "Unable to load module dm-crypt"
+                               dev="${luks_device}"
+                       else
+                               # skip $dev since we failed/chose not to open it
                                continue
                        fi
+               elif echo ${PERSISTENT_ENCRYPTION} | grep -qve "\<none\>"
+               then
+                       # skip $dev since we don't allow unencrypted storage
+                       continue
+               fi
 
-                       if [ ! -x /lib/cryptsetup/askpass ] || [ ! -x /sbin/cryptsetup ]
+               # Probe for filesystems with matching label
+               if echo ${PERSISTENT_STORAGE} | grep -qe "\<filesystem\>"
+               then
+                       result=$(probe_for_fs_label "${overlays}" "${snapshots}" ${dev})
+                       if [ -n "${result}" ]
                        then
-                               log_warning_msg "cryptsetup in unavailable"
+                               ret="${ret} ${result}"
                                continue
                        fi
+               fi
 
-                       if ! /sbin/cryptsetup isLuks ${dev}
+               # Probe for files with matching name on mounted partition
+               if echo ${PERSISTENT_STORAGE} | grep -qe "\<file\>"
+               then
+                       result=$(probe_for_file_name "${overlays}" "${snapshots}" ${dev})
+                       if [ -n "${result}" ]
                        then
-                               # skip device since we strictly want luks devices
+                               ret="${ret} ${result}"
                                continue
                        fi
-
-                       load_keymap
-
-                       while true
-                       do
-                               /lib/cryptsetup/askpass "Enter passphrase for ${dev}: " | /sbin/cryptsetup -T 1 luksOpen ${dev} $(basename ${dev}) --key-file=-
-
-                               if [ 0 -eq ${?} ]
-                               then
-                                       luks_device="/dev/mapper/$(basename ${dev})"
-                                       dev="${luks_device}"
-                                       break
-                               fi
-
-                               echo >&6
-                               echo -n "There was an error decrypting ${dev} ... Retry? [Y/n] " >&6
-                               read answer
-
-                               if [ "$(echo "${answer}" | cut -b1 | tr A-Z a-z)" = "n" ]
-                               then
-                                       break
-                               fi
-                       done
-               fi
-
-               if echo ${PERSISTENT_STORAGE} | grep -qw filesystem
-               then
-                       for label in ${overlays} ${snapshots}
-                       do
-                               if [ "$(/sbin/blkid -s LABEL -o value $dev 2>/dev/null)" = "${label}" ]
-                               then
-                                       overlays=$(echo ${overlays} | sed -e "s|\<${label}\>||")
-                                       snapshots=$(echo ${snapshots} | sed -e "s|\<${label}\>||")
-                                       echo "${label}=${dev}"
-                                       # skip to the next device
-                                       continue 2
-                               fi
-                       done
                fi
 
-               if echo ${PERSISTENT_STORAGE} | grep -qw file
+               # Close luks device if it isn't used
+               if [ -z "${result}" ] && [ -n "${luks_device}" ] && \
+                  /sbin/cryptsetup status "${luks_device}" 1> /dev/null 2>&1
                then
-                       devfstype="$(get_fstype ${dev})"
-                       overlay_on_dev=""
-                       snapshot_on_dev=""
-                       backing="/$(basename ${dev})-backing"
-                       mkdir -p "${backing}"
-                       if is_supported_fs ${devfstype} && try_mount "${dev}" "${backing}" "rw" "${devfstype}"
-                       then
-                               for label in ${overlays}
-                               do
-                                       path=${backing}/${PERSISTENT_PATH}${label}
-                                       if [ -f "${path}" ]
-                                       then
-                                               overlays=$(echo ${overlays} | sed -e "s|\<${label}\>||")
-                                               overlay_on_dev="yes"
-                                               echo "${label}=$(setup_loop "${path}" "loop" "/sys/block/loop*")"
-                                       fi
-                               done
-
-                               for label in ${snapshots}
-                               do
-                                       for ext in squashfs cpio.gz ext2 ext3 ext4 jffs2
-                                       do
-                                               path="${PERSISTENT_PATH}${label}.${ext}"
-                                               if [ -f "${backing}/${path}" ]
-                                               then
-                                                       snapshots=$(echo ${snapshots} | sed -e "s|\<${label}\>||")
-                                                       snapshot_on_dev="yes"
-                                                       echo "${label}=${dev}:${backing}:${path}"
-                                               fi
-                                       done
-                               done
-                       fi
-                       if [ -z "${overlay_on_dev}" ]
-                       then
-                               umount ${backing} > /dev/null 2>&1 || true
-                               if [ -z "${snapshot_on_dev}" ] && [ -n "${luks_device}" ] && /sbin/cryptsetup status "${luks_device}" 1> /dev/null
-                               then
-                                       /sbin/cryptsetup luksClose "${luks_device}"
-                               fi
-                       fi
+                       /sbin/cryptsetup luksClose "${luks_device}"
                fi
        done
+
+       if [ -n "${ret}" ]
+       then
+               echo ${ret}
+       fi
 }
 
 get_mac ()
@@ -549,3 +981,365 @@ non_removable_dev ()
 
        echo "${ret}"
 }
+
+link_files ()
+{
+       # create source's directory structure in dest, and recursively
+       # create symlinks in dest to to all files in source. if mask
+       # is non-empty, remove mask from all source paths when
+       # creating links (will be necessary if we change root, which
+       # live-boot normally does (into $rootmnt)).
+
+       # remove multiple /:s and ensure ending on /
+       local src_dir="$(echo "${1}"/ | sed -e 's|/\+|/|g')"
+       local dest_dir="$(echo "${2}"/ | sed -e 's|/\+|/|g')"
+       local src_mask="${3}"
+
+       # This check can only trigger on the inital, non-recursive call since
+       # we create the destination before recursive calls
+       if [ ! -d "${dest_dir}" ];
+       then
+               log_warning_msg "Must link_files into a directory"
+               return
+       fi
+
+       find "${src_dir}" -mindepth 1 -maxdepth 1 | while read x; do
+               local src="${x}"
+               local dest="${dest_dir}$(basename "${x}")"
+               if [ -d "${src}" ];
+               then
+                       if [ -z "$(ls -A "${src}")" ];
+                       then
+                               continue
+                       fi
+                       if [ ! -d "${dest}" ];
+                       then
+                               mkdir -p "${dest}"
+                               prev="$(dirname "${dest}")"
+                               chown $(stat -c %u:%g "${prev}") "${dest}"
+                               chmod $(stat -c %a "${prev}") "${dest}"
+                       fi
+                       link_files "${src}" "${dest}" "${src_mask}"
+               else
+                       if [ -n "${src_mask}" ]
+                       then
+                               src="$(echo ${src} | sed "s|^${src_mask}||")"
+                       fi
+                       rm -rf "${dest}" 2> /dev/null
+                       ln -s "${src}" "${dest}"
+               fi
+       done
+}
+
+do_union () {
+       local unionmountpoint="${1}"    # directory where the union is mounted
+       local unionrw="${2}"            # branch where the union changes are stored
+       local unionro1="${3}"           # first underlying read-only branch (optional)
+       local unionro2="${4}"           # second underlying read-only branch (optional)
+
+       if [ "${UNIONTYPE}" = "aufs" ]
+       then
+               rw_opt="rw"
+               ro_opt="rr+wh"
+               noxino_opt="noxino"
+       elif [ "${UNIONTYPE}" = "unionfs-fuse" ]
+       then
+               rw_opt="RW"
+               ro_opt="RO"
+       else
+               rw_opt="rw"
+               ro_opt="ro"
+       fi
+
+       case "${UNIONTYPE}" in
+               unionfs-fuse)
+                       unionmountopts="-o cow -o noinitgroups -o default_permissions -o allow_other -o use_ino -o suid"
+                       unionmountopts="${unionmountopts} ${unionrw}=${rw_opt}"
+                       if [ -n "${unionro1}" ]
+                       then
+                               unionmountopts="${unionmountopts}:${unionro1}=${ro_opt}"
+                       fi
+                       if [ -n "${unionro2}" ]
+                       then
+                               unionmountopts="${unionmountopts}:${unionro2}=${ro_opt}"
+                       fi
+                       ( sysctl -w fs.file-max=391524 ; ulimit -HSn 16384
+                       unionfs-fuse ${unionmountopts} "${unionmountpoint}" ) && \
+                       ( mkdir -p /run/sendsigs.omit.d
+                       pidof unionfs-fuse >> /run/sendsigs.omit.d/unionfs-fuse || true )
+                       ;;
+
+               overlayfs)
+                       # XXX: can unionro2 be used? (overlayfs only handles two dirs, but perhaps they can be chained?)
+                       # XXX: and can unionro1 be optional? i.e. can overlayfs skip lowerdir?
+                       unionmountopts="-o noatime,lowerdir=${unionro1},upperdir=${unionrw}"
+                       mount -t ${UNIONTYPE} ${unionmountopts} ${UNIONTYPE} "${unionmountpoint}"
+                       ;;
+
+               *)
+                       unionmountopts="-o noatime,${noxino_opt},dirs=${unionrw}=${rw_opt}"
+                       if [ -n "${unionro1}" ]
+                       then
+                               unionmountopts="${unionmountopts}:${unionro1}=${ro_opt}"
+                       fi
+                       if [ -n "${unionro2}" ]
+                       then
+                               unionmountopts="${unionmountopts}:${unionro2}=${ro_opt}"
+                       fi
+                       mount -t ${UNIONTYPE} ${unionmountopts} ${UNIONTYPE} "${unionmountpoint}"
+                       ;;
+       esac
+}
+
+get_custom_mounts () {
+       # Side-effect: leaves $devices with live.persist mounted in ${rootmnt}/live/persistent
+       # Side-effect: prints info to file $custom_mounts
+
+       local devices="${1}"
+       local custom_mounts="${2}" # print result to this file
+       local rootmnt="${3}"       # should be set empty post-live-boot
+
+       local bindings="/bindings.list"
+       local links="/links.list"
+       rm -rf ${bindings} ${links} 2> /dev/null
+       local persistent_backing="${rootmnt}/live/persistent"
+
+       for device in ${devices}
+       do
+               if [ ! -b "${device}" ]
+               then
+                       continue
+               fi
+               local device_name="$(basename ${device})"
+               local backing="${persistent_backing}/${device_name}"
+               mkdir -p "${backing}"
+               local device_fstype="$(get_fstype ${device})"
+               if [ -z "${PERSISTENT_READONLY}" ]
+               then
+                       device_mount_opts="rw,noatime"
+               else
+                       device_mount_opts="ro,noatime"
+               fi
+               local device_used=""
+               mount -t "${device_fstype}" -o "${device_mount_opts}" "${device}" "${backing}"
+               local include_list="${backing}/${persistence_list}"
+               if [ ! -r "${include_list}" ]
+               then
+                       umount "${backing}"
+                       rmdir "${backing}"
+                       continue
+               fi
+
+               [ "${DEBUG}" = "Yes" ] && cp ${include_list} ${persistent_backing}/${persistence_list}.${device_name}
+               while read source dest options # < ${include_list}
+               do
+                       if echo ${source} | grep -qe "^[[:space:]]*\(#.*\)\?$"
+                       then
+                               # skipping empty or commented lines
+                               continue
+                       fi
+
+                       if echo ${dest} | grep -qe "^[^/]"
+                       then
+                               options="${dest}"
+                               dest="${source}"
+                       elif [ -z "${dest}" ]
+                       then
+                               dest="${source}"
+                       fi
+
+                       if echo ${dest} | grep -qe "^/\+$\|^/\+live\(/.*\)\?$"
+                       then
+                               # mounting on / or /live could cause trouble
+                               log_warning_msg "Skipping unsafe custom mount on ${dest}"
+                               continue
+                       fi
+
+                       for opt in $(echo ${options} | tr ',' ' ');
+                       do
+                               case "${opt}" in
+                                       linkfiles|union)
+                                               ;;
+                                       *)
+                                               log_warning_msg "Skipping custom mount with unkown option: ${opt}"
+                                               continue 2
+                                               ;;
+                               esac
+                       done
+
+                       # FIXME: handle case: we already have /a/b in
+                       # $bindings added from current $device, but
+                       # now we find /a -- /a should replace /a/b in
+                       # $bindings.
+
+                       # FIXME: handle case: we have /a in $bindings
+                       # from current $device, now we find /a/b, so
+                       # we skip /a/b
+
+                       # ensure that no multiple-/ occur in paths
+                       local full_source="$(echo ${backing}/${source}/ | sed -e 's|/\+|/|g')"
+                       local full_dest="$(echo ${rootmnt}/${dest}/ | sed -e 's|/\+|/|g')"
+                       device_used="yes"
+                       if echo ${options} | grep -qe "\<linkfiles\>";
+                       then
+                               echo "${full_source} ${full_dest} ${options}" >> ${links}
+                       else
+                               echo "${full_source} ${full_dest} ${options}" >> ${bindings}
+                       fi
+               done < ${include_list}
+
+               if [ -z "${device_used}" ]
+               then
+                       # this device was not used for / earlier, or
+                       # custom mount point now, so it's useless
+                       umount "${backing}"
+                       rmdir "${backing}"
+               fi
+       done
+
+       # We sort the list according to destination so we're sure that
+       # we won't hide a previous mount. We also ignore duplicate
+       # destinations in a more or less arbitrary way.
+       [ -e "${bindings}" ] && sort -k2 -sbu ${bindings} >> ${custom_mounts}
+       rm ${bindings}
+
+       # After all mounts are considered we add symlinks so they
+       # won't be hidden by some mount.
+       [ -e "${links}" ] && sort -k2 -sbu ${links} >> ${custom_mounts}
+       rm ${links}
+
+       rm -f ${bindings} ${links} 2> /dev/null
+       echo ${custom_mounts}
+}
+
+do_custom_mounts () {
+       local custom_mounts="${1}" # the ouput from get_custom_mounts()
+       local rootmnt="${2}"       # should be set empty post-live-boot
+
+       while read source dest options # < ${custom_mounts}
+       do
+               local opt_linkfiles=""
+               local opt_union=""
+               for opt in $(echo ${options} | tr ',' ' ');
+               do
+                        case "${opt}" in
+                               linkfiles)
+                                       opt_linkfiles="yes"
+                                       ;;
+                               union)
+                                       opt_union="yes"
+                                       ;;
+                       esac
+               done
+
+               if mountpoint -q "${dest}";
+               then
+                       log_warning_msg "Skipping custom mount ${source} on ${dest}: destination is already a mount point"
+                       continue
+               fi
+
+               # FIXME: we don't handle already existing
+               # non-directory files in the paths of both $source and
+               # $dest.
+
+               if [ ! -d "${dest}" ]
+               then
+                       # if ${dest} is in /home/$user, try fixing
+                       # proper ownership
+                       # FIXME: this should really be handled by
+                       # live-config since we don't know for sure
+                       # which uid a certain user has until then
+                       if echo ${dest} | grep -qe "^${rootmnt}/*home/\+[^/]\+"
+                       then
+                               path="/"
+                               for dir in $(echo ${dest} | sed -e 's|/\+| |g')
+                               do
+                                       path=${path}/${dir}
+                                       if [ ! -e ${path} ]
+                                       then
+                                               mkdir -p ${path}
+                                               # assume that the intended user is the first, which is usually the case
+                                               chown 1000:1000 ${path}
+                                       fi
+                               done
+                       else
+                               mkdir -p ${dest}
+                       fi
+               fi
+
+               # if ${source} doesn't exist on our persistent media
+               # we bootstrap it with $dest from the live filesystem.
+               # this both makes sense and is critical if we're
+               # dealing with /etc or other system dir.
+               if [ ! -d "${source}" ]
+               then
+                       if [ -n "${PERSISTENT_READONLY}" ] || [ -n "${opt_linkfiles}" ]
+                       then
+                               continue
+                       elif [ -n "${opt_union}" ]
+                       then
+                               # union's don't need to be bootstrapped
+                               mkdir "${source}"
+                       else
+                               # ensure that $dest is not copied *into* $source
+                               mkdir -p "$(dirname ${source})"
+                               cp -a "${dest}" "${source}"
+                       fi
+               fi
+
+               rofs_dest_backing=""
+               for d in ${rootmnt}/live/rofs/*
+               do
+                       if [ -n "${rootmnt}" ]
+                       then
+                               rofs_dest_backing="${d}/$(echo ${dest} | sed -e "s|${rootmnt}||")"
+                       else
+                               rofs_dest_backing="${d}/${dest}"
+
+                       fi
+                       if [ -d "${rofs_dest_backing}" ]
+                       then
+                               break
+                       else
+                               rofs_dest_backing=""
+                       fi
+               done
+
+               if [ -z "${PERSISTENT_READONLY}" ]
+               then
+                       if [ -n "${opt_linkfiles}" ]
+                       then
+                               links_source="${source}"
+                               links_dest="${dest}"
+                       elif [ -n "${opt_union}" ]
+                       then
+                               do_union ${dest} ${source} ${rofs_dest_backing}
+                       else
+                               mount --bind "${source}" "${dest}"
+                       fi
+               else
+                       if [ -n "${opt_linkfiles}" ]
+                       then
+                               links_dest="${dest}"
+                               dest="$(mktemp -d ${persistent_backing}/links_source-XXXXXX)"
+                               links_source="${dest}"
+                       fi
+                       if [ -n "${rootmnt}" ]
+                       then
+                               cow_dir="$(echo ${dest} | sed -e "s|${rootmnt}|/cow/|")"
+                       else
+                               cow_dir="/live/cow/${dest}"
+                       fi
+                       mkdir -p ${cow_dir}
+                       do_union ${dest} ${cow_dir} ${source} ${rofs_dest_backing}
+               fi
+
+               if [ -n "${opt_linkfiles}" ]
+               then
+                       link_files "${links_source}" "${links_dest}" "${rootmnt}"
+               fi
+
+               PERSISTENCE_IS_ON="1"
+               export PERSISTENCE_IS_ON
+       done < ${custom_mounts}
+}