#!/bin/bash
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; version 2 of the License.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.

version=0.15.15dev

shopt -s extglob

LIBDIR='/usr/lib/manjaro-tools'

[[ -r ${LIBDIR}/util-msg.sh ]] && source ${LIBDIR}/util-msg.sh

import ${LIBDIR}/util-fstab.sh

write_source() {
local src=$1 spec= label= uuid= comment=()

label=$(lsblk -rno LABEL "$1" 2>/dev/null)
uuid=$(lsblk -rno UUID "$1" 2>/dev/null)

# bind mounts do not have a UUID!

case $bytag in
    '')
    [[ $uuid ]] && comment=("UUID=$uuid")
    [[ $label ]] && comment+=("LABEL=$(mangle "$label")")
    ;;
    LABEL)
    spec=$label
    [[ $uuid ]] && comment=("$src" "UUID=$uuid")
    ;;
    UUID)
    spec=$uuid
    comment=("$src")
    [[ $label ]] && comment+=("LABEL=$(mangle "$label")")
    ;;
    *)
    [[ $uuid ]] && comment=("$1" "UUID=$uuid")
    [[ $label ]] && comment+=("LABEL=$(mangle "$label")")
    [[ $bytag ]] && spec=$(lsblk -rno "$bytag" "$1" 2>/dev/null)
    ;;
esac

[[ $comment ]] && printf '# %s\n' "${comment[*]}"

if [[ $spec ]]; then
    printf '%-20s' "$bytag=$(mangle "$spec")"
else
    printf '%-20s' "$(mangle "$src")"
fi
}

optstring_apply_quirks() {
local varname=$1 fstype=$2

# SELinux displays a 'seclabel' option in /proc/self/mountinfo. We can't know
# if the system we're generating the fstab for has any support for SELinux (as
# one might install Arch from a Fedora environment), so let's remove it.
optstring_remove_option "$varname" seclabel

case $fstype in
    f2fs)
    # These are Kconfig options for f2fs. Kernels supporting the options will
    # only provide the negative versions of these (e.g. noacl), and vice versa
    # for kernels without support.
    optstring_remove_option "$varname" noacl,acl,nouser_xattr,user_xattr
    ;;
    vfat)
    # Before Linux v3.8, "cp" is prepended to the value of the codepage.
    if optstring_get_option "$varname" codepage && [[ $codepage = cp* ]]; then
        optstring_remove_option "$varname" codepage
        optstring_append_option "$varname" "codepage=${codepage#cp}"
    fi
    ;;
esac
}

usage() {
cat <<EOF
usage: ${0##*/} [options] root

Options:
    -L             Use labels for source identifiers (shortcut for -t LABEL)
    -p             Exclude pseudofs mounts (default behavior)
    -P             Include printing mounts
    -t TAG         Use TAG for source identifiers
    -U             Use UUIDs for source identifiers (shortcut for -t UUID)

    -h             Print this help message

fstabgen generates output suitable for addition to an fstab file based on the
devices mounted under the mountpoint specified by the given root.

EOF
}

if [[ -z $1 || $1 = @(-h|--help) ]]; then
usage
exit $(( $# ? 0 : 1 ))
fi

while getopts ':LPpt:U' flag; do
case $flag in
    L)
    bytag=LABEL
    ;;
    U)
    bytag=UUID
    ;;
    P)
    pseudofs=1
    ;;
    p)
    pseudofs=0
    ;;
    t)
    bytag=${OPTARG^^}
    ;;
    :)
    die '%s: option requires an argument -- '\''%s'\' "${0##*/}" "$OPTARG"
    ;;
    ?)
    die '%s: invalid option -- '\''%s'\' "${0##*/}" "$OPTARG"
    ;;
esac
done
shift $(( OPTIND - 1 ))

(( $# )) || die "No root directory specified"
root=$1; shift

if ! mountpoint -q "$root"; then
die "$root is not a mountpoint"
fi

# handle block devices
findmnt -Recvruno SOURCE,TARGET,FSTYPE,OPTIONS,FSROOT "$root" |
    while read -r src target fstype opts fsroot; do
if (( !pseudofs )) && fstype_is_pseudofs "$fstype"; then
    continue
fi

# default 5th and 6th columns
dump=0 pass=2

src=$(unmangle "$src")
target=$(unmangle "$target")
target=${target#$root}

if (( !foundroot )) && findmnt "$src" "$root" >/dev/null; then
    # this is root. we can't possibly have more than one...
    pass=1 foundroot=1
fi

# if there's no fsck tool available, then only pass=0 makes sense.
if ! fstype_has_fsck "$fstype"; then
    pass=0
fi

if [[ $fsroot != / ]]; then
    if [[ $fstype = btrfs ]]; then
    opts+=,subvol=${fsroot#/}
    else
    # it's a bind mount
    src=$(findmnt -funcevo TARGET "$src")$fsroot
    if [[ $src -ef $target ]]; then
        # hrmm, this is weird. we're probably looking at a file or directory
        # that was bound into a chroot from the host machine. Ignore it,
        # because this won't actually be a valid mount. Worst case, the user
        # just re-adds it.
        continue
    fi
    fstype=none
    opts+=,bind
    pass=0
    fi
fi

# filesystem quirks
case $fstype in
    fuseblk)
    # well-behaved FUSE filesystems will report themselves as fuse.$fstype.
    # this is probably NTFS-3g, but let's just make sure.
    if ! newtype=$(lsblk -no FSTYPE "$src") || [[ -z $newtype ]]; then
        # avoid blanking out fstype, leading to an invalid fstab
        error 'Failed to derive real filesystem type for FUSE device on %s' "$target"
    else
        fstype=$newtype
    fi
    ;;
esac

optstring_apply_quirks "opts" "$fstype"

# write one line
write_source "$src"
printf '\t%-10s' "/$(mangle "${target#/}")" "$fstype" "$opts"
printf '\t%s %s' "$dump" "$pass"
printf '\n\n'
done

# handle swaps devices
{
# ignore header
read

while read -r device type _ _ prio; do
    options=defaults
    if [[ $prio != -1 ]]; then
    options+=,pri=$prio
    fi

    # skip files marked deleted by the kernel
    [[ $device = *'\040(deleted)' ]] && continue

    if [[ $type = file ]]; then
    printf '%-20s' "$device"
    elif [[ $device = /dev/dm-+([0-9]) ]]; then
    # device mapper doesn't allow characters we need to worry
    # about being mangled, and it does the escaping of dashes
    # for us in sysfs.
    write_source "$(dm_name_for_devnode "$device")"
    else
    write_source "$(unmangle "$device")"
    fi

    printf '\t%-10s\t%-10s\t%-10s\t0 0\n\n' 'none' 'swap' "$options"
done
} </proc/swaps
