====== slcan unter Linux ======
Mithilfe von //udev// soll die Funktion realisiert werden, dass sobald der UsbTuCan angesteckt wird, dieser auch als socketcan Device attached wird und beim abstecken automatisch wieder entfernt wird.


===== udev Regeln =====
<code>
maxi@duplo:~/code/can-utils$ cat /etc/udev/rules.d/90-usb2can.rules 
ACTION=="add", SUBSYSTEM=="tty", ATTRS{idVendor}=="4c54", ATTRS{idProduct}=="5543", RUN+="/usr/local/bin/slcan-udev"
ACTION=="remove", SUBSYSTEM=="tty", ENV{ID_VENDOR_ID}=="4c54", ENV{ID_MODEL_ID}=="5543", RUN+="/usr/local/bin/slcan-udev"

</code>

===== Shellscript für udev =====
<code>
maxi@duplo:~/code/can-utils$ cat /usr/local/bin/slcan-udev
#!/bin/bash
# script to automatically configure slcan through udev
# (c) Maximilian Pachl, m@ximilian.info
# 2015-10-10


# -----------------------------------------------------
# configuration
# -----------------------------------------------------

LOG_FILE="/tmp/slcan.log"
PID_PREFIX="/var/run/slcan"


# -----------------------------------------------------
# helper functions
# -----------------------------------------------------

log()
{
	echo "[$(date)] $1" >> $LOG_FILE;
}

get_tty()
{
	echo $DEVNAME | awk -F "/" '{print $NF}'
}


# -----------------------------------------------------
# udev action handler
# -----------------------------------------------------

add()
{
	TTY=$(get_tty)
	log "new slcan compatible device $TTY found"

	# attch tty to a slcan device
	INTERFACE=$(slcan_attach -s8 -o $DEVNAME | awk 'NF>1{print $NF}')

	# start the slcan userspace daemon
	slcand $TTY $INTERFACE
	echo $(pgrep -f "slcand $TTY $INTERFACE") > $PID_PREFIX-$TTY

	# bring interface up
	ifconfig $INTERFACE up
	log "succesfully configured $TTY as $INTERFACE"
}

remove()
{
	TTY=$(get_tty)
	log "slcan device $(get_tty) removed"
	PID=$(cat "$PID_PREFIX-$TTY")
	kill $PID
	rm $PID_PREFIX-$TTY
	log "successfully removed $TTY, stopped $PID"
}


# -----------------------------------------------------
# main
# -----------------------------------------------------

# check if all environment variables are supplied
if [ -z "$DEVNAME" ]; then
	log "no DEVNAME name supplied"
        exit 1
fi

if [ -z "$ACTION" ]; then
	log "no ACTION supplied"
        exit 1
fi


# process the action issued by udev
case "$ACTION" in
	add)	add;;
	remove)	remove;;
esac
</code>