#!/bin/bash
# Copyright 2011-2016 Mir Calculate. http://www.calculate-linux.org
#
#  Licensed under the Apache License, Version 2.0 (the "License");
#  you may not use this file except in compliance with the License.
#  You may obtain a copy of the License at
#
#      http://www.apache.org/licenses/LICENSE-2.0
#
#  Unless required by applicable law or agreed to in writing, software
#  distributed under the License is distributed on an "AS IS" BASIS,
#  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
#  See the License for the specific language governing permissions and
#  limitations under the License.

# first param - autologin user
XUSER=${1:-guest}
# number of virtual console
TTYNUM=${2:-7}
# number of virtual console
DISPLAYNUM=${3:-\:0}
MAINLOOP=1

# write pid for init.d/xdm (detect X for this xautologin)
echo $BASHPID >/var/run/bash.pid

# function for kill X server by TERM,INT,QUIT signals
killXserver()
{
    KILLXPID=$XPID
    XPID=
    MAINLOOP=
    # kill X by TERM
    [[ -d /proc/$KILLXPID ]] && kill $KILLXPID &>/dev/null
    # wait 5 sec
    for i in {0..5}
    do
        [[ -d /proc/$KILLXPID ]] || break
        sleep 1
    done
    WAITRELOGIN=
    # kill X by -KILL
    [[ -d /proc/$KILLXPID ]] && kill -KILL $KILLXPID &>/dev/null
}

# function for waiting X server
waitX() {
    displaynum=${1#:}
    usingvt="using VT number"
    errorX="no screens found"
    successX="evdev"
    logfile=/var/log/Xorg.${displaynum}.log
    for i in 0.1 0.2 0.5 1
    do
        sleep $i
        if [[ -f $logfile ]]
        then
            for x in 0.5 1 2 4
            do
                grep -q "$errorX" $logfile && return 1
                grep -q "$successX" $logfile && return 0
                sleep $x
            done
            return 1
        fi
    done
    return 1
}

trap killXserver SIGTERM SIGINT SIGQUIT

# rerun x session for XUSER while not shutdown and bash not receivce TERM
HOMEDIR=`getent passwd $XUSER | awk -F: '{ print( $6 ); }'`
[[ -d $HOMEDIR ]] || mkdir $HOMEDIR
# export display num
export DISPLAY=${DISPLAYNUM}
export XAUTHORITY=$HOMEDIR/.Xauthority

WAITRELOGIN=7
while id $XUSER &>/dev/null && 
       [[ -n $MAINLOOP ]] &&
       [[ "$(rc-status -r)" != "shutdown" ]]
do
    # disable relogin by fourth param
    if [[ "$4" == "off" ]];then
        MAINLOOP=
    fi
    # prepare user xauthority
    mcookie | sed -e "s/^/add ${DISPLAYNUM} . /" | xauth -f $XAUTHORITY -q
    chown $XUSER. $XAUTHORITY
    chmod 600 $XAUTHORITY
    # perform user profile setting up
    X ${DISPLAYNUM} -auth $XAUTHORITY vt${TTYNUM} -noreset &
    XPID=$!
    if waitX ${DISPLAYNUM}
    then
        env USER=${XUSER} /usr/share/calculate/xdm/xdm --login || break
        # write pam enviroment for pam_ck_connector
        cat >/home/${XUSER}/.pam_environment <<EOF
CKCON_DISPLAY_DEVICE=
CKCON_X11_DISPLAY_DEVICE=/dev/tty${TTYNUM}
CKCON_X11_DISPLAY=${DISPLAYNUM}
EOF
        # registry user in utmp and wtmp
        sessreg -a -l ${DISPLAYNUM} ${XUSER}
        # run x session for user XUSER in background
        su - ${XUSER} -c 'source /etc/profile
# replace xinit for startx
xinit()
{
    # if file is script run it throught bash
    if file $1 | grep -1 "POSIX shell script"
    then
        /bin/bash $*
    else
        $*
    fi
}
# run script start xsession
source /usr/bin/startx' &
        # wait for right work trap SIGTERM
        XSESSIONPID=$!
        while [[ -d /proc/$XSESSIONPID ]] &&
            [[ "$(rc-status -r)" != "shutdown" ]]
        do
            sleep 1
        done
        # remove user from utmp and wtmp
        sessreg -d -l ${DISPLAYNUM} ${XUSER}
        # perform logout scripts for user
        if [[ -n $WAITRELOGIN ]]
        then
            sleep $WAITRELOGIN
        fi
        env USER=${XUSER} /usr/share/calculate/xdm/xdm --logout
    fi
    [[ -n $XPID ]] && kill $XPID
    wait $XPID
done

exit 0
