#!/bin/bash
# $Id$

udev_version()
{
	local version=0

	if [[ -x /sbin/udev ]]
	then
		version=$(/sbin/udev -V)
	elif [[ -x /sbin/udevd ]]
	then
		version=$(/sbin/udevd --version)
	elif [[ -x /lib/udev/udevd ]]
	then
		version=$(/lib/udev/udevd --version)
	elif [[ -x /usr/lib/systemd/systemd-udevd ]]
	then
		version=$(/usr/lib/systemd/systemd-udevd --version)
	fi

	# We need it without a leading '0', else bash do the wrong thing
	version=${version##0}
	# Older udev's will print nothing
	[[ -z ${version} ]] && version=0

	echo "${version}"
}

populate_udev()
{
	local opts

	# populate /dev with devices already found by the kernel
	rc_print "  Populating /dev with existing devices through uevents ..."
	if [[ ${RC_COLDPLUG} = yes ]]
	then
		udevadm trigger
	else
		# do not run any init-scripts
		udevadm control --property=do_not_run_plug_service=1

		udevadm trigger --type=subsystems --action=add
		udevadm trigger --type=devices --action=add
	fi
	evaluate_retval

	# unset this variable
	udevadm control --property=do_not_run_plug_service=

	return 0
}

seed_dev()
{
	# seed /dev with some things that we know we need
	rc_print "  Seeding /dev with needed nodes ..."
	(
		[ ! -c /dev/console ] && mknod -m 600 /dev/console c 5 1
		[ ! -c /dev/tty1 ] && mknod -m 620 /dev/tty1 c 4 1
		[ ! -c /dev/tty ] && mknod -m 666 /dev/tty c 5 0
		[ ! -c /dev/null ] && mknod -m 666 /dev/null c 1 3

		# create kmsg too, so udev can add its start-message to dmesg
		[ -c /dev/kmsg ] || mknod -m 660 /dev/kmsg c 1 11

		# create problematic directories
		mkdir -p /dev/pts /dev/shm
	)
	evaluate_retval
}

# main function
start_devicemanager()
{
	local udev_prefix=""
	local udev_daemon=""

	# get the right daemon and prefix for newer udev/systemd-udev installations
	if [ -x /sbin/udevd ]
	then
		udev_daemon="/sbin/udevd"
		udev_prefix=""
	elif [ -x /lib/udev/udevd ]
	then
		udev_daemon="/lib/udev/udevd"
		udev_prefix=""
	elif [ -x /usr/lib/systemd/systemd-udevd ]
	then
		udev_daemon="/usr/lib/systemd/systemd-udevd"
		udev_prefix="/usr"
	fi

	# check if /dev/console exists outside tmpfs
	[ -c /dev/console ] ; need_redirect=$?

	# create a ramdisk for populating udev
	if [[ -z $(grep '[[:space:]]/dev[[:space:]]' /proc/self/mountinfo) ]]
	then
		rc_print "Mounting udev at /dev ..."
		# many video drivers needed exec access
		fstype=ramfs
		# tmpfs was suggested by Greg Kroah-Hartman
		kernel_supports_fs tmpfs && fstype=tmpfs
		# mount devtmpfs if supported 
		kernel_supports_fs devtmpfs && fstype=devtmpfs
		mount -n -t ${fstype} dev /dev -o exec,nosuid,mode=0755,size=10M
		evaluate_retval
	fi

	# if a device tarball exists load it but only if it is activated in the config
	rc_print "Configurating system to use udev ..."
	if [[ ${RC_DEVICE_TARBALL} = yes ]]
	then
		if [[ -f ${udev_prefix}/lib/udev/state/devices.tar.bz2 ]]
		then
			rc_print "  Populating /dev with saved device nodes ..."
			tar -jxpf ${udev_prefix}/lib/udev/state/devices.tar.bz2 -C /dev
			evaluate_retval
		fi
	fi

	# other needed device nodes with udev
	seed_dev

	if [ -e /proc/sys/kernel/hotplug ]
	then
		rc_print "  Using netlink for hotplug events ..."
		echo "" > /proc/sys/kernel/hotplug
		evaluate_retval
	else
		rc_print ${COLYELLOW}"  Kernel was not compiled with hotplug support !"
		print_status failure
	fi

	# load unix domain sockets if built as module
	if [ -e /proc/modules ]
	then
		modprobe -q unix 2>/dev/null
	fi

	rc_print "  Starting udevd daemon ..."
	if [ ${need_redirect} -eq 1 ]
	then
		# we need to open fds 0 1 2
		start-stop-daemon --start --exec "${udev_daemon}" -- --daemon </dev/console >/dev/console 2>/dev/console
	else
		start-stop-daemon --start --exec "${udev_daemon}" -- --daemon
	fi
	evaluate_retval

	# write root_link rule
	if [ -x ${udev_prefix}/lib/udev/write_root_link_rule ]
	then
		${udev_prefix}/lib/udev/write_root_link_rule
	fi

	# populate udev device nodes
	populate_udev

	# create nodes that udev can't
	rc_print "  Finializing udev configuration ..."
	[[ -x /sbin/dmsetup ]] && /sbin/dmsetup mknodes &>/dev/null
	[[ -x /sbin/lvm ]] && /sbin/lvm vgscan -P --mknodes --ignorelockingfailure &>/dev/null
	[[ -x /sbin/evms_activate ]] && /sbin/evms_activate -q &>/dev/null
	print_status success

	# same thing as /dev/.devfsd
	touch /dev/.udev
}

stop_devicemanager()
{
	local udev_daemon=""

	# get the right daemon and prefix for newer udev/systemd-udev installations
	if [ -x /sbin/udevd ]
	then
		udev_daemon="/sbin/udevd"
	elif [ -x /lib/udev/udevd ]
	then
		udev_daemon="/lib/udev/udevd"
	elif [ -x /usr/lib/systemd/systemd-udevd ]
	then
		udev_daemon="/usr/lib/systemd/systemd-udevd"
	fi

	rc_print "Stopping udevd daemon ..."
	start-stop-daemon --stop --exec "${udev_daemon}"
	evaluate_retval
}