#!/bin/bash

# Filepath: /usr/local/bin/usbdrive.sh

# Script to automount usb drive
# This script should be executed from a udev rule.
# Run directly with: bash /usr/local/bin/usbdrive.sh

# Copyright 2015 Per Stenebo
# Created 2015-01-27 by Per Stenebo

# Updated 2015-01-28: Dev and testing on a Raspberry Pi B+ with Raspbian.

#-----------------------------------------------------------------------
# Configuration
#-----------------------------------------------------------------------
# Check command path: which mount
mountpath=/bin/mount

# Array of device files to try, in given order:
devicefiles=( 
	/dev/sda1
	/dev/sda2
	/dev/sdb1
	/dev/sdb2
	/dev/sdc1
	/dev/sdc2
	)

mountpoint=/media/usbdrive


#-----------------------------------------------------------------------
# Check that this script is only running in one instance
#-----------------------------------------------------------------------
# Build absolute path to process lock file, like /tmp/usbdrive.pid
lockfile=/tmp/$(basename $0 | sed 's/\.sh//g').pid;

# Check if lock file exist
if [ -f $lockfile ]; then
	
	# Fetch PID from file
	read filepid < $lockfile
	
	# Check if PID is alive
	if [ ! -z "$filepid" ] && [ -d /proc/$filepid ]; then
		
		# Debug
		logger "${0}: PID $filepid seems alive, I kill myself now"
		
		# Terminate
		exit 1;
	fi
fi

# Write current PID to file
echo $$ > $lockfile

# Debug
logger "${0}:64 started | ACTION: ${ACTION} | param 1: [${1}] | param 2: [${2}]"


# Allow device to get ready
sleep 3

#-----------------------------------------------------------------------
# Prepare mount
#-----------------------------------------------------------------------
# Check mount point
if [ ! -d "${mountpoint}" ]; then
	
	# Create mount point
	mkdir -p ${mountpoint}
	
	logger "${0}: ${mountpoint} created"
	
elif [ $(mount | grep -c ${mountpoint}) -ne 0 ]; then
	logger "${0}: ERROR: ${mountpoint} already mounted"
	mountpoint=''
fi

# Set device file
deviceFound=0

# Loop configured device files
for devicefile in ${devicefiles[@]}; do
	
	# Check device file
	if [ -b "${devicefile}" ] && [ $(mount | grep -c ${devicefile}) -eq 0 ]; then
		# We found available unmounted device
		deviceFound=1
		break
	fi
done

#-----------------------------------------------------------------------
# Mount
#-----------------------------------------------------------------------
deviceMounted=0

if [ -z ${mountpoint} ]; then
	: # Pass
	
elif [ ${deviceFound} -eq 0 ]; then
	logger "${0}: ERROR: device file not found"
	
else
	
	# /bin/mount /dev/sda1 /media/usbdrive
	${mountpath} ${devicefile} ${mountpoint}
	
	if [ $(mount | grep -c ${mountpoint}) -eq 1 ]; then
		logger "${0}: ${devicefile} mounted on ${mountpoint}"
		deviceMounted=1
	else
		logger "${0}: ERROR: Failed to mount ${devicefile} on ${mountpoint}"
	fi
fi

#-----------------------------------------------------------------------
# Do other actions
#-----------------------------------------------------------------------
if [ ${deviceMounted} -eq 1 ]; then
	logger "${0}: We can do som stuff with ${mountpoint}"
fi


#-----------------------------------------------------------------------
# Unmount
#-----------------------------------------------------------------------
if [ ${deviceMounted} -eq 1 ]; then
	
	umount ${mountpoint}
	
	if [ $(mount | grep -c ${mountpoint}) -eq 0 ]; then
		logger "${0}: ${devicefile} unmounted from ${mountpoint}"
		deviceMounted=1
	else
		logger "${0}: ERROR: Failed to unmount ${devicefile} from ${mountpoint}"
	fi
fi

#-----------------------------------------------------------------------
# Finish
#-----------------------------------------------------------------------
exit 0