#!/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=@version@

shopt -s extglob

[[ -r @libdir@/util.sh ]] && source @libdir@/util.sh
[[ -r @libdir@/util-msg.sh ]] && source @libdir@/util-msg.sh
[[ -r @libdir@/util-mount.sh ]] && source @libdir@/util-mount.sh
[[ -r @libdir@/util-fstab.sh ]] && source @libdir@/util-fstab.sh

if [ $EUID -ne 0 ]; then
    echo -e "\n${0##*/} must be run with root privileges !\n"
    exit 1
fi

mountpoint=/mnt/repchroot

if [ -d $mountpoint ]; then
    old_IFS=$IFS
    IFS=$'\n'
    for i in $(mount | grep "$mountpoint" | tac | awk '{print $3}')
    do
        umount $mountpoint 2>/dev/null
    done
    IFS=$old_IFS
else
    mkdir -p $mountpoint 2>/dev/null
fi

curetc=$(df /etc | sed -n '/^\//p')
curetc=${curetc%% *}
list=()
nbpart=0

# Search for partitions containing /etc
for i in $(ls /dev/[hs]d[a-z][1-9]*)
do
    [ $i = "$curetc" ] && continue
    mount $i $mountpoint 2>/dev/null
    if [ $? -eq 0 ]; then
        if [ -d $mountpoint/etc ]; then
            list[$nbpart]=$i
            ((nbpart++))
        fi
    fi
    # -l below necesary, don't know why !?!?!?
    umount -l $mountpoint 2>/dev/null
done

# Exit if no other linux system available
if [ $nbpart -eq 0 ]; then
    echo -e "\nNo linux system found !\n"
    sleep 5
    exit 1
fi

if [ $nbpart != 1 ]; then
    echo -e "\nList of found systems"
    echo -e "====================="
    for((i=0; i < $nbpart; i++))
    do
        v=${list[$i]}
        l=$(e2label $v)
        [ ! -z $l ] && l='('$l')'
        echo "$i) $v $l"
    done

    # Choice of the system to chroot
    echo -en "\nPlease enter your choice [0-$((nbpart-1))] : "
    while read n
    do
        if [[ $n = +([0-9]) ]]; then
            [ $n -lt $nbpart ] && break
        fi
        echo -en "\nPlease enter your choice [0-$((nbpart-1))] : "
    done
else
    n=0
fi

echo ${list[n]}

# mount /
mount ${list[n]} $mountpoint

# mount /boot (if exists)
#cat $mountpoint/etc/fstab
indboot=false
boot=$(grep -s '^[^#].*[      ]/boot[         ]' /$mountpoint/etc/fstab)
if [ $? -eq 0 ]; then
    indboot=true
    comm=$(echo $boot | awk '{print "mount -t " $3 " " $1}')
    comm=${comm}" $mountpoint/boot"
    $comm
fi

# mount /home (if exists)
indhome=false
home=$(grep -s '^[^#].*[      ]/home[         ]' /$mountpoint/etc/fstab)
if [ $? -eq 0 ]; then
    indhome=true
    comm=$(echo $home | awk '{print "mount -t " $3 " " $1}')
    comm=${comm}" $mountpoint/home"
    $comm
fi

# activate swap (if exists and not already activated)
indswap=$(swapon -s)
if [ -z "$indswap" ]; then
    swap=$(grep -s '^[^#].*[      ]swap[         ]' /$mountpoint/etc/fstab)
    if [ $? -eq 0 ]; then
        comm=$(echo $swap | awk '{print "swapon " $1}')
        echo $comm
        $comm
    fi
fi

chroot_api_mount "$mountpoint"
chroot_mount /etc/resolv.conf "$mountpoint/etc/resolv.conf" --bind

# mount proc, sys, dev and chroot
# mount -B /proc    $mountpoint/proc
# mount -B /dev     $mountpoint/dev
# mount -B /sys     $mountpoint/sys
# mount -B /dev/pts $mountpoint/dev/pts
# mount -B /tmp     $mountpoint/tmp
# # mount /run if it exists
# [ -d $mountpoint/run ] && mount -B /run $mountpoint/run
# cp /etc/resolv.conf $mountpoint/etc/resolv.conf
# read the architecture of the target
elf=$(file $mountpoint/usr/bin/file)
elf=${elf#*ELF *}
elf=${elf%%-*}
if [ "$elf" == 32 ]; then
    arch=i686
else
    arch=x86_64
    if [ $(uname -m) == i686 ]; then
        echo "Error : impossible to chroot from a 32 to a 64 system"
        sleep 5
        exit 1
    fi
fi

setarch $arch chroot $mountpoint /bin/bash
#[ -d $mountpoint/run ] && umount -f $mountpoint/run
#umount -f $mountpoint/{tmp,dev/pts,sys,dev,proc}
[ $indhome = true ] && umount $mountpoint/home
[ $indboot = true ] && umount $mountpoint/boot
umount $mountpoint
rmdir $mountpoint
exit 0