Functions to find and mount Crouton & ChrUbuntu partitions

.crouton_funcs

# Exits the script with return code $1, spitting out message $@ to stderr
error() {
    local ecode="$1"
    shift
    echo "$*" 1>&2
    return "$ecode"
}

# Find the root drive
# Sets:
#  - $ROOTDEVICE as the root device (e.g. /dev/sda or /dev/mmcblk0)
#  - $ROOTDEVICEPREFIX as a prefix for partitions (/dev/sda, /dev/mmcblk0p)
findrootdevice() {
    if hash rootdev 2>/dev/null; then
    #   ROOTDEVICE="`rootdev -s`"
        ROOTDEVICE="`rootdev -d -s`"
    elif hash rdev 2>/dev/null; then
    # grab the root partition and extract the drive id
        ROOTDEVICE="`rdev|cut -d' ' -f1|sed 's/.$//'`"
#   elif hash blkid 2>/dev/null; then
#   # This can be DANGEROUS!
#   # Just grab the FIRST partition and extract the drive id
#       ROOTDEVICE=`blkid -o device|head -n1|sed 's/.$//'`
    else
        RDEV=$(mountpoint -d /)
        for file in $(find /dev); do
            if [ $(stat --printf="%t:%T" "$file") = $RDEV ]; then
                ROOTPART="$file"; break
            fi
        done
        ROOTDEVICE="`echo "$ROOTPART"|sed 's/.$//'`"
    fi

    if [ -z "$ROOTDEVICE" ]; then
        error 1 "Cannot find root device."
    fi

    if [ ! -b "$ROOTDEVICE" ]; then
        error 1 "$ROOTDEVICE is not a block device."
    fi

    # If $ROOTDEVICE ends with a number (e.g. mmcblk0), partitions are named
    # ${ROOTDEVICE}pX (e.g. mmcblk0p1). If not (e.g. sda), they are named
    # ${ROOTDEVICE}X (e.g. sda1).
    ROOTDEVICEPREFIX="$ROOTDEVICE"
    if [ "${ROOTDEVICE%[0-9]}" != "$ROOTDEVICE" ]; then
        ROOTDEVICEPREFIX="${ROOTDEVICE}p"
    fi
}

# Try to mount the CROUTON partition, if it exists, on $MOUNTCROUTON.
mountcrouton() {
    # Define CROUTON mountpoint
    # $1 Sets:
    #  - $MOUNTCROUTON as mountpoint for CROUTON partition
    if [ -n "$1" ]; then
        MOUNTCROUTON="$1"
    else
        MOUNTCROUTON='/var/crouton'
    fi

    if [ -z "$ROOTDEVICE" -o -z "$ROOTDEVICEPREFIX" ]; then
        findrootdevice
    fi

    PRIOR=' not'
    local croutonpart="`sudo cgpt find -n -l CROUTON "$ROOTDEVICE"`"
    if [ -z "$croutonpart" ]; then
      error 1 "Warning: CROUTON partition was not found on $ROOTDEVICE."
      return 1
    fi

    # Check to make sure $croutonpart is greater than 1
    if [ ! `sudo cgpt show -i $croutonpart -s $ROOTDEVICE` -gt 1 ]; then
      error 1 "!!!CROUTON partition $croutonpart is not formatted."
      return 1
    fi

    # Check if crouton is mounted already
    if grep -q "^${ROOTDEVICEPREFIX}$croutonpart " /proc/mounts; then
        # If mounted, it must be mounted to $mountpoint
        if ! grep -q "^${ROOTDEVICEPREFIX}$croutonpart $MOUNTCROUTON " /proc/mounts; then
            error 1 "Error: CROUTON partition is not mounted on $MOUNTCROUTON."
        else
            PRIOR=' already'
        fi
    else
        sudo mkdir -p "$MOUNTCROUTON" || error 1 "Cannot create $MOUNTCROUTON."
        sudo mount "${ROOTDEVICEPREFIX}$croutonpart" "$MOUNTCROUTON" || \
            error 1 "Cannot mount $MOUNTCROUTON"
        PRIOR=' now'
    fi
    return 0
}

# Try to mount the ChrUbuntu partition, if it exists, on $MOUNTCHRUBUNTU.
mountchrubuntu() {
    # Define CHRUBUNTU mountpoint
    # $1 Sets:
    #  - $MOUNTCHRUBUNTU as mountpoint for CHRUBUNTU partition
    if [ -n "$1" ]; then
        MOUNTCHRUBUNTU="$1"
    else
        MOUNTCHRUBUNTU='/var/chrubuntu'
    fi
    if [ -z "$ROOTDEVICE" -o -z "$ROOTDEVICEPREFIX" ]; then
        findrootdevice
    fi

    PRIOR=' not'
    local chrubuntupart="`sudo cgpt find -n -l ROOT-C "$ROOTDEVICE"`"
    if [ -z "$chrubuntupart" ]; then
        chrubuntupart="`sudo cgpt find -n -l CHRUBUNTU "$ROOTDEVICE"`"
    fi

    if [ -z "$chrubuntupart" ]; then
        error 1 "Warning: CHRUBUNTU partition was not found on $ROOTDEVICE."
        return 1
    fi

    # Check to make sure $chrubuntupart is greater than 1
    if [ ! `sudo cgpt show -i $chrubuntupart -s $ROOTDEVICE` -gt 1 ]; then
      error 1 "!!!CHRUBUNTU partition $chrubuntupart is not formatted."
      return 1
    fi

    # Check if chrubuntu is mounted already
    if grep -q "^${ROOTDEVICEPREFIX}$chrubuntupart " /proc/mounts; then
        # If mounted, it must be mounted to $mountpoint
        if ! grep -q "^${ROOTDEVICEPREFIX}$chrubuntupart $MOUNTCHRUBUNTU " /proc/mounts; then
            error 1 "Error: CHRUBUNTU partition is not mounted on $MOUNTCHRUBUNTU."
        else
            PRIOR=' already'
        fi
    else
        sudo mkdir -p "$MOUNTCHRUBUNTU" || error 1 "Cannot create $MOUNTCHRUBUNTU."
        sudo mount "${ROOTDEVICEPREFIX}$chrubuntupart" "$MOUNTCHRUBUNTU" || \
            error 1 "Cannot mount $MOUNTCHRUBUNTU"
        PRIOR=' now'
    fi
    return 0
}