Personal Computer World 2007 September/PCWSEP07.iso/Software/Linux/Linux Mint 3.0 Light/LinuxMint-3.0-Light.iso/casper/filesystem.squashfs/boot/initrd.img-2.6.20-15-generic/initrd.img-2.6/scripts/casper-helpers

Text File | 2007-05-25 | 5.1 KB | 198 lines

## Casper helper functions, used by casper on boot and by casper-snapshot

if [ "${BUILD_SYSTEM}" = "Ubuntu" ]; then
    MP_QUIET="-Q"
elif [ "${BUILD_SYSTEM}" = "Debian" ]; then
    MP_QUIET="-q"
else
    MP_QUIET=""
fi

if [ ! -x "/bin/fstype" ]; then
    # klibc not in path -> not in initramfs
    export PATH="${PATH}:/usr/lib/klibc/bin"
fi

sys2dev() {
    sysdev=${1#/sys}
    echo "/dev/$(udevinfo -q name -p ${sysdev} 2>/dev/null|| echo ${sysdev##*/})"
}

subdevices() {
    sysblock=$1
    r=""
    for dev in "${sysblock}" "${sysblock}"/*; do
        if [ -e "${dev}/dev" ]; then
            r="${r} ${dev}"
        fi
    done
    echo ${r}
}

get_fstype() {
    local FSTYPE
    local FSSIZE
    eval $(fstype < $1)
    if [ "$FSTYPE" != "unknown" ]; then
        echo $FSTYPE
        return 0
    fi
    /lib/udev/vol_id -t $1 2>/dev/null
}

where_is_mounted() {
    device=$1
    if grep -q "^$device " /proc/mounts; then
        grep "^$device " /proc/mounts | read d mountpoint rest
        echo $mountpoint
        return 0
    fi
    return 1
}

lastline() {
    while read lines ; do
        line=${lines}
    done
    echo "${line}"
}

base_path ()
{
    testpath="${1}"
    mounts="$(awk '{print $2}' /proc/mounts)"
    testpath="$(busybox realpath ${testpath})"

    while true ; do
        if echo "${mounts}" | grep -qs "^${testpath}" ; then
            set -- `echo "${mounts}" | grep "^${testpath}" | lastline`
            echo ${1}
            break
        else
            testpath=`dirname $testpath`
        fi
    done
}

fs_size ()
{
    # Returns used/free fs kbytes + 5% more
    # You could pass a block device as $1 or the mount point as $2

    dev="${1}"
    mountp="${2}"
    used="${3}"

    if [ -z "${mountp}" ]; then
        mountp=$(where_is_mounted "${dev}")
        if [ "$?" -gt 0 ]; then
            mountp="/mnt/tmp_fs_size"
            mkdir -p "${mountp}"
            mount -t $(get_fstype "${dev}") -o ro "${dev}" "${mountp}"
            doumount=1
        fi
    fi

    if [ "${used}" = "used" ]; then
        size=$(du -ks ${mountp} | cut -f1)
        size=$(expr ${size} + ${size} / 20 ) # FIXME: 5% more to be sure
    else
        # free space
        size="$(df -k | grep -s ${mountp} | awk '{print $4}')"
    fi

    if [ -n "${doumount}" ]; then
        umount "${mountp}"
        rmdir "${mountp}"
    fi
    echo "${size}"
}

setup_loop() {
    local fspath=$1
    local module=$2
    local pattern=$3
    local offset=$4

    modprobe ${MP_QUIET} -b "$module"
    udevsettle

    for loopdev in $pattern; do
        if [ "$(cat $loopdev/size)" -eq 0 ]; then
            dev=$(sys2dev "${loopdev}")
            if [ -n "$offset" ]; then
                losetup -o "$offset" "$dev" "$fspath"
            else
                losetup "$dev" "$fspath"
            fi
            echo "$dev"
            return 0
        fi
    done
    panic "No loop devices available"
}

try_mount ()
{
    dev="${1}"
    mountp="${2}"
    opts="${3}"

    if where_is_mounted ${dev} > /dev/null; then
        mount -o remount,"${opts}" ${dev} $(where_is_mounted ${dev}) || panic "Remounting failed"
        mount -o bind $(where_is_mounted ${dev}) ${mountp} || panic "Cannot bind-mount"
    else
        mount -t $(get_fstype "${dev}") -o "${opts}" "${dev}" "${mountp}" || panic "Cannot mount ${dev} on ${mountp}"
    fi
}

find_cow_device() {
    pers_label="${1}"
    cow_backing="/${pers_label}-backing"
    for sysblock in $(echo /sys/block/* | tr ' ' '\n' | grep -v loop); do
        for dev in $(subdevices "${sysblock}"); do
            devname=$(sys2dev "${dev}")
            if [ "$(/lib/udev/vol_id -l $devname 2>/dev/null)" = "${pers_label}" ]; then
                echo "$devname"
                return
            elif [ "$(get_fstype ${devname})" = "vfat" ]; then # FIXME: all supported block devices should be scanned
                mkdir -p "${cow_backing}"
                try_mount "${devname}" "${cow_backing}" "rw"
                if [ -e "${cow_backing}/${pers_label}" ]; then
                    echo $(setup_loop "${cow_backing}/${pers_label}" "loop" "/sys/block/loop*")
                    return 0
                else
                    umount ${cow_backing}
                fi
            fi
        done
    done
}

find_files()
# return the first of $filenames found on vfat and ext2 devices
# FIXME: merge with above function
{
    filenames="${1}"
    snap_backing="/snap-backing"
    for sysblock in $(echo /sys/block/* | tr ' ' '\n' | grep -v loop); do
        for dev in $(subdevices "${sysblock}"); do
            devname=$(sys2dev "${dev}")
            devfstype="$(get_fstype ${devname})"
            if [ "${devfstype}" = "vfat" ] ||  [ "${devfstype}" = "ext2" ] ; then # FIXME: all supported block devices should be scanned
                mkdir -p "${snap_backing}"
                try_mount "${devname}" "${snap_backing}" "ro"
                for filename in ${filenames}; do
                    if [ -e "${snap_backing}/${filename}" ]; then
                        echo "${devname} ${snap_backing} ${filename}"
                        return 0
                    fi
                done
                umount ${snap_backing}
            fi
        done
    done
}