#!/bin/bash
# -*- mode: sh; indent-tabs-mode: nil; sh-basic-offset: 4; -*-
# vim: et sts=4 sw=4

#  SPDX-License-Identifier: LGPL-2.1+
#
#  Copyright © 2020 Collabora Ltd.
#  Copyright © 2020 Valve Corporation.
#
#  This file is part of steamos-customizations.
#
#  steamos-customizations is free software; you can redistribute it and/or
#  modify it under the terms of the GNU Lesser General Public License as
#  published by the Free Software Foundation; either version 2.1 of the License,
#  or (at your option) any later version.

set -e
set -o pipefail
set -u

usage() {
    cat <<EOF
Usage: ${0##*/} [-o fs-options] DEVICE MOUNTPOINT
       ${0##*/} -u MOUNTPOINT

Mount all the SteamOS filesystems on MOUNTPOINT using the DEVICE partitions.

Options:
 -o, --options <list>    comma-separated list of mount options
 -u                      umount
 -h, --help              display this help

Options for disk:
 partset=<self|other|A|B|dev>
                         explicitly specifies partset
 noesp                   no mount /esp
 noefi                   no mount /efi
 novar                   no mount /var (implies nooverlay and noboot)
 nohome                  no mount /home (implies nooffload)
 nooffload               no bind-mount offloaded directories
 nooverlay               no mount overlayed /etc
 noboot                  no bind-mount /boot
EOF
}

partset="${partset:-other}"
while [[ "$#" -ne 0 ]]
do
    if [[ "$1" =~ ^(-h|--help)$ ]]
    then
        usage
        exit
    elif [[ "$1" =~ ^(-u)$ ]]
    then
        unmount=1
    elif [[ "$1" =~ ^(-o) ]]
    then
        if [[ "$1" == "-o" ]]
        then
            shift
            opt="$1"
        elif [[ "$1" =~ ^-o= ]]
        then
            opt="${1/-o=/}"
        else
            opt="${1/-o/}"
        fi

        IFS=, read -a opts <<<"$opt"
        for opt in "${opts[@]}"
        do
            if [[ "${opt%%=*}" = "$opt" ]]
            then
                opt+="=1"
            fi
            eval "$(echo "$opt")"
        done
    elif [[ "${dev:-}" ]] || ( [[ -n "${unmount:-}" ]] && [[ "${mnt:-}" ]] )
    then
        usage
        echo "$1: Too many arguments" >&2
        exit 1
    elif [[ ! "${mnt:-}" ]]
    then
        mnt="$1"
    else
        dev="$mnt"
        mnt="$1"
    fi
    shift
done

if [[ ! "${mnt:-}" ]]
then
    usage
    exit 1
fi

# Unmount all partitions
if [[ "${unmount:-}" ]]
then
    exec umount -R "$mnt"
fi

# Mount all partitions
if [[ ! "${dev:-}" ]]
then
    usage
    exit 1
fi

# Get the list of partitions
case "${partset:-other}" in
A|B|dev)
    PARTITIONS=("efi-$partset" "rootfs-$partset" "var-$partset")
    ;;
*)
    if [[ ! -d "/dev/disk/by-partsets/$partset" ]]
    then
        echo "$partset: No such partset" >&2
        exit 1
    fi

    mapfile -t PARTITIONS < <(blkid -s PARTLABEL -o value "/dev/disk/by-partsets/$partset"/*)
    ;;
esac
PARTITIONS+=("esp" "home")

# Get the devices
mapfile -t devs < <(sfdisk -o "device,name" -l "$dev" | sed -n '/Device/,/^$/{//d;p}')
declare -A devices
for dev in "${devs[@]}"
do
    read -r -a device < <(echo "$dev")
    if [[ ${#device[@]} -lt 2 ]]
    then
        continue
    fi

    # check if the device is a SteamOS partition using the GPT partition label:
    for part in "${PARTITIONS[@]}"
    do
        if [[ "$part" == "${device[1]}" ]]
        then
            devices[${device[1]}]="${device[0]}"
            break
        fi
    done
done

for dev in "${!devices[@]}"
do
    case "$dev" in
    esp)
        esp="${devices[$dev]}"
        ;;
    efi-*)
        efi="${devices[$dev]}"
        ;;
    rootfs-*)
        rootfs="${devices[$dev]}"
        ;;
    var-*)
        var="${devices[$dev]}"
        ;;
    home)
        home="${devices[$dev]}"
        ;;
    esac
done

if [[ ! "${esp:-}" ]]
then
    # Get the first EFI System Partition
    mapfile -t esps < <(sfdisk -o "device,uuid,type" -l "$dev" | sed -n '/Device/,/^$/{//d;/EFI System$/p}')
    for dev in "${esps[@]}"
    do
        read -r -a device < <(echo "$dev")
        if [[ ${#device[@]} -lt 2 ]]
        then
            continue
        fi

        esp="${device[0]}"
        break
    done
fi

if [[ ! "${noesp:-}" ]] && [[ ! "${esp:-}" ]]
then
    echo "esp: No such device" >&2
    exit 1
elif [[ ! "${noefi:-}" ]] && [[ ! "${efi:-}" ]]
then
    echo "efi: No such device" >&2
    exit 1
elif [[ ! "${rootfs:-}" ]]
then
    echo "rootfs: No such device" >&2
    exit 1
elif [[ ! "${novar:-}" ]] && [[ ! "${var:-}" ]]
then
    echo "var: No such device" >&2
    exit 1
elif [[ ! "${nohome:-}" ]] && [[ ! "${home:-}" ]]
then
    echo "home: No such device" >&2
    exit 1
fi

# Mount partset
mount "$rootfs" "$mnt"
trap 'umount -R "$mnt"' 0
if [[ ! "${nohome:-}" ]]
then
    mount "$home" "$mnt/home"
fi
if [[ ! "${novar:-}" ]]
then
    mount "$var" "$mnt/var"
fi
if [[ ! "${noefi:-}" ]]
then
    mount "$efi" "$mnt/efi"
fi
if [[ ! "${noesp:-}" ]]
then
    mount "$esp" "$mnt/esp"
fi

# Mount offload
if [[ ! "${nohome:-}" ]] && [[ ! "${nooverlay:-}" ]]
then
    for i in /opt /root /srv /usr/lib/debug /usr/local
    do
        mount --bind "$mnt/home/.steamos/offload$i" "$mnt$i"
    done
    if [[ ! "${novar:-}" ]]
    then
        for i in /var/cache/pacman /var/lib/docker /var/lib/flatpak /var/lib/systemd/coredump /var/log /var/tmp
        do
            mount --bind "$mnt/home/.steamos/offload$i" "$mnt$i"
        done
    fi
fi

# Mount overlay
if [[ ! "${novar:-}" ]] && [[ ! "${nooverlay:-}" ]]
then
    mount -t overlay -o "lowerdir=$mnt/etc,upperdir=$mnt/var/lib/overlays/etc/upper,workdir=$mnt/var/lib/overlays/etc/work" none "$mnt/etc"
fi

# Mount boot
if [[ ! "${novar:-}" ]] && [[ ! "${noboot:-}" ]]
then
    mount --bind "$mnt/var/boot" "$mnt/boot"
fi
trap - 0