klog

#!/bin/bash
#
USAGE="usage: klog [make (ovs <ovs dir>|alone) (verbose|silent), start <path>, stop]"
#
# Description
#
# `klog make`, defaulting to `alone` and `silent`, builds a standalone module.
# For openvswitch support, type `klog make ovs <ovs dir>`.
# 
# <ovs dir> points to the ovs directory.
#
# The last argument of `klog make` is always either `verbose` or `silent`. 
#
# Once either module is compiled, load it with `klog start`. 
#
# If compiled with openvswitch, start with
# `klog start <ovs dir>/datapath/linux`, i.e. the path to the module.
#
# Unload it with
# `klog stop`.
#
# In summary:
#
# a) For a stand-alone version,
#
# $ sudo klog make
# $ sudo klog start
#
# b) For a version compatible with openvswitch 1.2.1 (cf. homework at 
#    github),
#
# $ sudo klog make ovs $HOME/homework/openvswitch.git
# $ sudo klog start $HOME/homework/openvswitch.git/datapath/linux
#
VERBOSE=false

klog_perror () {

	[ -z "$1" ] && echo "error" || echo "$@"
	exit 1
}

klog_conf_log () {
	
	[ ! -e "debug.h" ] && klog_perror "debug.h not found"
	
	if [ \( "$1" != "silent" \) -a \( "$1" != "verbose" \) ]; then
		return 1
	fi

	# edit debug.h
	rm -f debug.tmp
	next=false
	tf="debug.tmp"
	while read line; do

		if $next; then
			if [ "$1" == "silent" ]; then
				echo "#undef HWDB_VERBOSE"  >> $tf
			else
				echo "#define HWDB_VERBOSE" >> $tf
			fi
			next=false
		else
			echo "$line" >> $tf
		fi
		[ "$line" = "/*klog:var:log*/" ] && next=false
	
	done < debug.h
	[ ! -f $tf ] && return 1
	mv $tf debug.h
	return 0
}

klog_have_ovs () {
	
	[ ! -e "klogger.h" ] && klog_perror "klogger.h not found"

	# edit klogger.h
	rm -f klogger.tmp
	next=false
	tf="klogger.tmp"
	while read line; do

		if $next; then
			if ! $1; then
				echo "#undef OVS_HWDB"  >> $tf
			else
				echo "#define OVS_HWDB" >> $tf
			fi
			next=false
		else
			echo "$line" >> $tf
		fi
		[ "$line" = "/*klog:var:ovs*/" ] && next=true
		
	done < klogger.h
	[ ! -f $tf ] && return 1 
	mv $tf klogger.h
	return 0
}

klog_conf_ovs () {

	OVS=$1

	actions=$OVS/datapath/actions.c
	modules=$OVS/datapath/linux/Modules.mk

	[ ! -e "$actions" ] && klog_perror "$actions not found"
	[ ! -e "$modules" ] && klog_perror "$modules not found"
	
	t=`pwd`
	
	diff $t/patches/actions.c $actions &>/dev/null
	if [ $? -eq 1 ]; then
		cp $actions ${actions}.orig
		$VERBOSE && echo "$actions => ${actions}.orig"
		cp $t/patches/actions.c $actions
		$VERBOSE && echo "$t/patches/actions.c => $actions"
	fi
	
	diff $t/patches/Modules.mk $modules &>/dev/null
	if [ $? -eq 1 ]; then 
		cp $modules ${modules}.orig
		$VERBOSE && echo "$modules => ${modules}.orig"
		cp $t/patches/Modules.mk $modules
		$VERBOSE && echo "$t/patches/Modules.mk => $modules"
	fi
	
	# cp files
	cp klogger.* hashtable.* hwdbflow.* khwdb.h debug.h \
$OVS/datapath/linux/
	# make
	cd $OVS/datapath/
	make
	cd $t
}

[ $# -eq 0 ] && klog_perror $USAGE
$VERBOSE && echo "[args] $@"

action="$1"
case "$action" in
"make")
[ $# -eq 1 ] && klog_perror $USAGE
shift 1
$VERBOSE && echo "[args] $@"
[ $# -lt 2 ] && klog_perror $USAGE
# There is at least a second argument
if [ "$1" == "alone" ]; then
	make clean
	klog_have_ovs false
	klog_conf_log "$2" || klog_perror $USAGE
	make
	exit $? # done
elif [ "$1" == "ovs" ]; then
	shift 1
	$VERBOSE && echo "[args] $@"
	[ $# -ne 2 ] && klog_perror $USAGE
	# Next argument is a directory
	[ ! -d "$1" ] && klog_perror $USAGE
	make clean
	klog_have_ovs true
	klog_conf_log "$2" || klog_perror $USAGE
	klog_conf_ovs "$1"
	exit $? # done
else
	plog_error $USAGE
fi
;;
"start")
DIR=
MOD="klogger"
[ $# -eq 2 ] && DIR=$2
if [ -n $DIR ]; then
	[ ! -d $DIR ] && klog_perror "$DIR not found"
	MOD="$DIR/klogger_mod"
fi
/sbin/insmod $MOD.ko || klog_perror "failed to load $DIR/$MOD.ko"
# retrieve major number
major=$(awk "\$2==\"hwdb\" {print \$1}" /proc/devices)
$VERBOSE && echo "hwdb's major number $major"
# remove stale nodes
rm -f /dev/hwdb[0-3]
# klogger has four devices
mknod /dev/hwdb0 c $major 0
mknod /dev/hwdb1 c $major 1
mknod /dev/hwdb2 c $major 2
mknod /dev/hwdb3 c $major 3
ln -sf hwdb0 /dev/hwdb
if grep -q '^staff:' /etc/group; then
	group="staff"
else
	group="wheel"
fi
chgrp $group /dev/hwdb[0-3] 
chmod 667 /dev/hwdb[0-3] # or 664
exit 0
;;
"stop")
MOD="klogger"
/sbin/lsmod | grep klogger_mod &>/dev/null
[ $? -eq 0 ] && MOD="klogger_mod"
/sbin/rmmod $MOD 2>/dev/null || klog_perror "$MOD not loaded"
rm -f /dev/hwdb /dev/hwdb[0-3]
exit 0
;;
*)
klog_perror $USAGE
;;
esac

exit 1