#! /usr/bin/env bash
#
# mountall - mount all suitable block devices
# 
# Author: Gerd v. Egidy
# SPDX-License-Identifier: GPL-3.0-or-later
#
# see https://www.system-rescue.org/scripts/mountall/ for details

# abort on failures
set -o errexit -o pipefail -o noclobber -o nounset

print_help()
{
    echo "mountall - mount all suitable block devices"
    echo ""
    echo "Usage:"
    echo "mountall [-n|--no-bind] [-v|--verbose]"
    echo ""
    echo "--no-bind                   Don't try to bind-mount /dev /proc and /sys when"
    echo "                            the partition has these dirs"
    echo "--verbose                   Verbose output."
    echo ""
    echo "See https://www.system-rescue.org/scripts/mountall/ for details."
    
    return
}

# error while parsing commandline parameters
argument_error()
{
    echo "$1"
    echo
    echo "---------------------------------"
    echo
    print_help
    exit 2
}

parse_args()
{
    # adapted from https://stackoverflow.com/a/29754866 by Robert Siemer
    # version edited Mar 4 '21 at 0:11, licensed under CC BY-SA 4.0 due to Stackoverflow Terms of Service
    # https://creativecommons.org/licenses/by-sa/4.0/

    # -allow a command to fail with !’s side effect on errexit
    # -use return value from ${PIPESTATUS[0]}, because ! hosed $?
    ! getopt --test > /dev/null 
    if [[ ${PIPESTATUS[0]} -ne 4 ]]; then
        echo 'ERROR: `getopt --test` failed in this environment'
        exit 1
    fi

    local OPTIONS="nvh"
    local LONGOPTS="no-bind,verbose,help"

    # option variables as globals, set to default values
    declare -g BIND=1
    declare -g VERBOSE=0
    
    # -regarding ! and PIPESTATUS see above
    # -temporarily store output to be able to check for errors
    # -activate quoting/enhanced mode (e.g. by writing out “--options”)
    # -pass arguments only via   -- "$@"   to separate them correctly
    ! PARSED=$(getopt --options=$OPTIONS --longoptions=$LONGOPTS --name "$0" -- "$@")
    if [[ ${PIPESTATUS[0]} -ne 0 ]]; then
        # e.g. return value is 1
        #  then getopt has complained about wrong arguments to stdout
        echo
        print_help
        exit 2
    fi
    # read getopt’s output this way to handle the quoting right:
    eval set -- "$PARSED"

    while true; do
        case "$1" in
            -n|--no-bind)
                BIND=0
                shift
                ;;
            -v|--verbose)
                VERBOSE=1
                shift
                ;;
            -h|--help)
                print_help
                exit 0
                ;;
            --)
                shift
                break
                ;;
            *)
                echo "ERROR: Argument parsing logic bug"
                exit 2
                ;;
        esac
    done

    # we want no positional arguments 
    [[ $# -ne 0 ]] && argument_error "ERROR: positional arguments not allowed"
    
    true
}

is_cryptodev()
{
    local DEV="$1"

    [[ $VERBOSE -eq 1 ]] && echo "Checking if $DEV is an encrypted device..."

    BLKID=$(blkid "$DEV")
    [[ $VERBOSE -eq 1 ]] && echo "blkid output: $BLKID"

    if [[ "$BLKID" != *" TYPE="* ]] && [[ "$BLKID" != "TYPE="* ]]; then
        # blkid must return a "TYPE" tag for it to be mountable at all
        [[ $VERBOSE -eq 1 ]] && echo "$DEV is not mountable (no TYPE)"
        false
        return
    fi

    if [[ "$BLKID" != *"TYPE=\"crypto"* ]]; then
        [[ $VERBOSE -eq 1 ]] && echo "$DEV is not not encrypted"
        false
        return
    fi

    # is the device already opened?
    DEVNAME=$(basename "$DEV")
    if /usr/bin/test -d /sys/devices/virtual/block/*/slaves/$DEVNAME ; then
        [[ $VERBOSE -eq 1 ]] && echo "$DEV is already opened"
        false
        return
    fi

    [[ $VERBOSE -eq 1 ]] && echo "$DEV looks to be an encrypted device that could be opened"

    true
}

is_mountable()
{
    local DEV="$1"

    [[ $VERBOSE -eq 1 ]] && echo "Checking if $DEV is mountable..."
    
    BLKID=$(blkid "$DEV")
    [[ $VERBOSE -eq 1 ]] && echo "blkid output: $BLKID"

    if [[ "$BLKID" != *" TYPE="* ]] && [[ "$BLKID" != "TYPE="* ]]; then
        # blkid must return a "TYPE" tag for it to be mountable at all
        [[ $VERBOSE -eq 1 ]] && echo "$DEV is not mountable (no TYPE)"
        false
        return
    fi
    
    if [[ "$BLKID" == *"TYPE=\"linux_raid_member\""* ]] ||
        [[ "$BLKID" == *"TYPE=\"LVM2_member\""* ]] ||
        [[ "$BLKID" == *"TYPE=\"swap\""* ]] ||
        [[ "$BLKID" == *"TYPE=\"crypto"* ]] ; then
        # these are not directly mountable
        [[ $VERBOSE -eq 1 ]] && echo "$DEV is not mountable (swap, RAID or LVM)"
        false
        return
    fi

    if findmnt --source "$DEV" >/dev/null 2>&1 ; then
        [[ $VERBOSE -eq 1 ]] && echo "$DEV is already mounted"
        false
        return
    fi
    
    [[ $VERBOSE -eq 1 ]] && echo "$DEV looks to be mountable"
    
    true
}

# create a suitable dir below /mnt
# tries to use the block dev name, but uses a different one if already existing
create_mountpoint()
{
    local DEV="$1"

    DEVNAME=$(basename "$DEV")
    
    MOUNTPOINT="/mnt/$DEVNAME"
    local NUMBER=1

    while [[ -e "$MOUNTPOINT" ]]; do
        [[ $VERBOSE -eq 1 ]] && echo "wanted mountpoint $MOUNTPOINT already existing, choosing a different one"
        MOUNTPOINT="/mnt/${DEVNAME}_${NUMBER}"
        NUMBER=$[$NUMBER+1]
    done

    [[ $VERBOSE -eq 1 ]] && echo "creating mountpoint $MOUNTPOINT"
    
    if ! mkdir "$MOUNTPOINT"; then
        echo "error creating mountpoint $MOUNTPOINT"
        false
        return
    fi
}

# if there is /dev /proc /sys in the just mounted path, bind mount them to ours
# this allows using some commands in a chroot (like grub-install)
try_bind_mounts()
{
    local MOUNTPOINT="$1"

    [[ $VERBOSE -eq 1 ]] && echo "checking if to create bind-mounts below $MOUNTPOINT"
    
    if [[ -d "${MOUNTPOINT}/dev" ]]; then
        if mount --bind "/dev" "${MOUNTPOINT}/dev"; then
            echo "bind mounted /dev to ${MOUNTPOINT}/dev"
        else
            echo "failed bind mounting /dev to ${MOUNTPOINT}/dev"
        fi
    fi
    
    if [[ -d "${MOUNTPOINT}/sys" ]]; then
        if mount --bind "/sys" "${MOUNTPOINT}/sys"; then
            echo "bind mounted /sys to ${MOUNTPOINT}/sys"
        else
            echo "failed bind mounting /sys to ${MOUNTPOINT}/sys"
        fi
    fi
    
    if [[ -d "${MOUNTPOINT}/proc" ]]; then
        if mount --bind "/proc" "${MOUNTPOINT}/proc"; then
            echo "bind mounted /proc to ${MOUNTPOINT}/proc"
        else
            echo "failed bind mounting /proc to ${MOUNTPOINT}/proc"
        fi
    fi
}

try_mount()
{
    local DEV="$1"

    echo -n "mounting $DEV... "
    
    create_mountpoint "$DEV" || return

    if ! mount "$DEV" "$MOUNTPOINT"; then
        echo "error mounting $DEV"
        return
    fi
    
    echo "OK"
    
    if [[ $BIND -eq 1 ]]; then
        try_bind_mounts "$MOUNTPOINT"
    fi
}

#################################
# execution begins here

parse_args "$@"

# loop through regular block devices
for BLKDEV in $(ls -1 "/sys/class/block"); do
    # handle device mapper / lvm volumes in the 2nd loop for nice names
    [[ -d "/sys/class/block/${BLKDEV}/dm" ]] && continue

    if is_cryptodev "/dev/${BLKDEV}"; then
        if /usr/bin/cryptsetup open "/dev/${BLKDEV}" "${BLKDEV}_crypt"; then
            # we will handle the opened crypto volume in the mapper loop below
            continue
        else
            echo "error opening ${BLKDEV}"
        fi
    fi

    if is_mountable "/dev/${BLKDEV}"; then
        try_mount "/dev/${BLKDEV}"
    fi
done

# loop through device mapper / lvm volumes
for LVMDEV in $(ls -1 "/dev/mapper"); do
    # there is always one central control entry, skip it
    [[ "$LVMDEV" == "control" ]] && continue

    if is_cryptodev "/dev/mapper/${LVMDEV}"; then
        if /usr/bin/cryptsetup open "/dev/mapper/${LVMDEV}" "${LVMDEV}_crypt"; then
            # check if we can mount the opened device below
            LVMDEV="${LVMDEV}_crypt"
        else
            echo "error opening ${LVMDEV}"
        fi
    fi
    
    if is_mountable "/dev/mapper/${LVMDEV}"; then
        try_mount "/dev/mapper/${LVMDEV}"
    fi
done

exit 0