#!/bin/sh
#----------------------------------------------------------------------------
# /etc/init.d/mtab - initial boot script
#
# Creation   :  2015-06-20 hbfl
# Last Update:  $Id$
#
# Copyright (c) 2015-@@YEAR@@ the eisfair team, team(at)eisfair(dot)org
#
# 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; either version 2 of the License, or
# (at your option) any later version.
#----------------------------------------------------------------------------

# ---------------------------------------------------------------------------
# Update the mount program's mtab file after
# all local filesystems have been mounted.
# ---------------------------------------------------------------------------

lsb=false

if ${lsb}
then
    # read init-functions
    . /lib/lsb/init-functions
else
    # read functions
    . /etc/init.d/functions
fi

# ---------------------------------------------------------------------------
# usage
# ---------------------------------------------------------------------------
usage()
{
cat <<EOF

 Usage:
 ${0}
                -q, --quiet      suppress all normal output
                [start]
EOF
}

# ---------------------------------------------------------------------------
# start
# ---------------------------------------------------------------------------
start()
{
    # look in an easy way to where root is mounted from
    ROOTFS=$( /usr/bin/awk '/^[^#]/ && / \/ / {print $1}' /etc/fstab )

    if /usr/bin/grep -q "${ROOTFS}" /proc/self/mounts
    then
        # /etc/mtab -> symlink to /proc/self/mounts
        mtab=true

        if ! /usr/bin/readlink /etc/mtab | /usr/bin/grep -wq 'proc/self/mounts'
        then
            call_dir=$( pwd )
            cd /etc
            /usr/bin/rm -f mtab
            /usr/bin/ln -s ../proc/self/mounts mtab
            cd ${call_dir}
        fi

    fi

    if ! ${mtab:-false}
    then  
        if /usr/bin/grep -q '/dev/root' /proc/self/mounts
        then
            # /etc/mtab -> regular file
            mtab=true
            mtab_file=true   
            _old_rootfs='/dev/root'
        fi
    fi

    if ! ${mtab:-false}
    then
        _root_device=$( /usr/bin/cat /proc/cmdline | /usr/bin/sed 's/^.*root=\(.*\) .*$/\1/' )

        if /usr/bin/grep -q "${_root_device}" /proc/self/mounts
        then
            # /etc/mtab -> regular file
            mtab=true
            mtab_file=true
            _old_rootfs="${_root_device}"
        fi
   fi


    if ${mtab_file:-false}
    then
        # remove the old file
        /usr/bin/rm -f /etc/mtab

        # create /etc/mtab
        /usr/bin/awk '$1 != "rootfs" {print}' /proc/self/mounts |
            /usr/bin/sed "s%${_old_rootfs}%${ROOTFS}%" > /etc/mtab
    fi

    # Remove stale backups
    /usr/bin/rm -f /etc/mtab~ /etc/mtab~~
}

# ---------------------------------------------------------------------------
# main
# ---------------------------------------------------------------------------
main()
{
    while [ ${#} -gt 0 ]
    do
        case "${1}" in
        -q|--quiet)
            _quiet=true
            shift
            ;;
        *)
            _action=${1}
            shift
            ;;
        esac
    done

    case "${_action}" in
    start)
        start
        ;;
    *)
        usage
        exit 1
        ;;
    esac

    exit 0
}

# ---------------------------------------------------------------------------
# call function main
# ---------------------------------------------------------------------------
main "${@}"

# ---------------------------------------------------------------------------
# end
# ---------------------------------------------------------------------------