#!/bin/dash

# Unlocks SIM K3765-Z broadband modem.
#    Copyright (C) 2011  Gero Treuner
#
#    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 3 of the License, or
#    (at your option) any later version.
#
#    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.
#
#    See <http://www.gnu.org/licenses/>



# Attention:
# - Check permissions of this script, so that your PIN is not revealed.
# - Replace the string DEVICE_SERIAL with the serial number of your
#   device, which is checked before operation.
# - Replace the string DEVICE_PIN with your PIN, or you may risk to
#   exceed the SIM retry counter and require to enter the PUK!

# Permanent lock prevention:
# The script stores a sane result in the file $VARRUNDIR/accepted .
# It continues operation until this file is removed. The reason is to
# prevent further trying, otherwise after 3 failed attempts the SIM
# could lock permanently and require a PUK. To initially start
# operation call this script with the "-force" option.



VARRUNDIR=/var/run/k3765-z_unlock
PATH=/usr/bin:/bin:/usr/sbin
TTY=/dev/ttyUSB1
DEVICE_SERIAL=<YourSerialNumber>
DEVICE_PIN=<YourPIN>
DEBUG=false



if ! test -d $VARRUNDIR
then
	echo "The required directory $VARRUNDIR does not exist. Exiting."
	exit 1
fi



# Delete enabling file on start for permanent lock prevention

if test -f $VARRUNDIR/accepted
then
	rm -f $VARRUNDIR/accepted
	if test -f $VARRUNDIR/accepted
	then
		if test "$1" = "-force"
		then
			echo "Could not delete control file $VARRUNDIR/accepted. Ignore..."
		else
			echo "Could not delete control file $VARRUNDIR/accepted. Exiting."
			exit 2
		fi
	fi
else
	if ! test "$1" = "-force"
	then
			echo "Control file $VARRUNDIR/accepted does not exist.\nRisk of locking device permanently (until PUK is provided). Consider to use the -force option.\nExiting."
			exit 3
	fi
fi



# Check existence of device

if test -z "$DEVNAME"
then
	DEVNAME=$TTY
fi

if ! test -c "$DEVNAME"
then
	echo "File $DEVNAME does not exist or is not of type \"character special\". Exiting."
	exit 4
fi



# Chat with broadband modem

if test "$DEBUG" = true -o "$1" = "-force"
then
	CHATOPTIONS=-v
fi

chat $CHATOPTIONS -t5 <$DEVNAME >$DEVNAME \
ABORT ERROR \
ABORT '+CPIN: READY' \
ABORT '+CPIN: SIM PUK' \
OK-AT-OK-AT-OK-AT-OK-AT-OK-AT-OK AT+CGSN \
$DEVICE_SERIAL AT+CPIN? \
'+CPIN: SIM PIN' AT+CPIN=${DEVICE_PIN} \
OK



# Save result

RESULT=$?

if test "$RESULT" = 0
then
	echo "PIN accepted." >$VARRUNDIR/accepted
else
	if test "$RESULT" = "5"
	then
		echo "Already unlocked." >$VARRUNDIR/accepted
	else
		exit 5
	fi
fi