#!/bin/sh
#
# Display driver helper
#
# Copyright (c) 2010, 2011 Anssi Hannula <anssi.hannula@iki.fi>
#
# - Load drivers for specified modaliases, skipping disabled display drivers
#   that would cause conflicts (KMS vs. vesa, KMS vs. proprietary).
# - Get information about enabled driver modules
# - Check that the loaded modules are correct
#
# Note that drivers not known by this script are handled normally, i.e.
# loaded automatically as udev normally would've.
#
# Licensed under terms of GPLv2 or later.
#
# When updating, check:
# - the variables below
# - check_driver function
# - check_dkms_status function
#

# DEBUG_DISPLAY_DRIVER_HELPER=yes

if [ -n "$DEBUG_DISPLAY_DRIVER_HELPER" ]; then
	echo "$(date) $*" >> /dev/ddh_debug
	exec 2>>/dev/ddh_debug
	set -x
fi

export LC_ALL=C

KMS_DRIVERS="i915 radeon nouveau"
# module names at run-time (hence nvidia instead of nvidia*):
KNOWN_MODULES="i915|radeon|nouveau|fglrx|nvidia"

XORG_i915="intel"
CONFLICTS_i915=""

XORG_nouveau="nouveau"
CONFLICTS_nouveau="nv nvidia"

XORG_radeon="ati radeon"
CONFLICTS_radeon="fglrx"

# Note: no /usr
# See end of script for descriptions of global variables.
check_driver() {
	local name="$1"
	case "$name" in
	i915)
		# implicitely loaded by X.org
		check_xorg $name 0 || return 1
		IS_KMS=1
		;;
	radeon)
		# implicitely loaded by X.org
		check_xorg $name 0 || return 1
		# Do not load if the proprietary driver is temporarily disabled
		# on a PowerXpress system.
		# TODO: this check could be omitted if radeon was explicitely
		# specified in xorg.conf - but that is only known by check_xorg.
		check_gl /etc/fglrx/pxpress-free.ld.so.conf && return 1
		IS_KMS=1
		# radeon needs to be loaded before X server
		NEEDS_LOAD_NOW=1
		;;
	nouveau)
		# these KMS drivers require an explicit directive in xorg.conf
		check_xorg $name 1 || return 1
		IS_KMS=1
		;;
	fglrx)
		check_xorg fglrx 1 || return 1
		check_dkms fglrx || return 1
		;;
	nvidia)
		# manually installed driver or a call from check_loaded()
		UNSURE=1
		check_xorg nvidia 1 || return 1
		;;
	nvidiafb)
		# this is only reached if nvidiafb is manually unblacklisted
		return 2
		;;
	nvidia*)
		[ "$name" = "nvidia_current" ] && name=nvidia-current
		# there are multiple co-installable driver versions, so check
		# the active alternative as well
		check_gl /etc/$name/ld.so.conf || return 1
		check_xorg nvidia 1 || return 1
		check_dkms $name || return 1
		;;
	*)
		# unknown, will be loaded only if no known drivers were found
		return 2
		;;
	esac
	return 0
}

# Return success if there is no new pending DKMS build (needed to disallow
# speedboot on very early boot).
# Previously failed build or a missing module is counted as no pending build.
# Note: no /usr
check_dkms_status() {
	[ -e /etc/alternatives/gl_conf ] || return 0
	# return fast for non-DKMS
	check_gl /etc/ld.so.conf.d/GL/standard.conf && return 0

	local active="$(ls -l /etc/alternatives/gl_conf | awk '{ print $NF }')"

	local modname=

	case $active in
	/etc/nvidia*/ld.so.conf)
		modname="nvidia${active#*nvidia}"
		modname="${modname%/*}"
		;;
	/etc/ld.so.conf.d/GL/ati.conf)
		modname="fglrx"
		;;
	*)
		# Unknown DKMS-looking driver,
		# allow speedboot.
		return 0
		;;
	esac
	check_dkms "$modname" 1
}

# Check if all loaded kernel modules have correct xorg.conf
check_loaded() {
	for module in $(grep -oE "^($KNOWN_MODULES) " /proc/modules); do
		# try to unload the driver in case it is not in use before bailing
		check_driver "$module" || rmmod "$module" &>/dev/null || return 1
	done
	return 0
}

# Check that specified DKMS driver is not queued for build for the current
# kernel. Used to check if we 1) should disable speedboot for this boot
# (--check-dkms-status), and 2) if should should load the currently
# existing driver (--load). Doing otherwise might cause us to load a wrong old
# version of the driver that had been installed using e.g. binary DKMS
# packages.
# Note: no /usr
check_dkms() {
	local driver="$1"
	local force="$2"

	# If called from DKMS itself or we are not in rc.sysinit anymore,
	# there are no pending builds.
	if [ -z "$force" ]; then
		[ "$DKMS_AUTOLOAD_MODULE" = "$driver" ] && return 0
		[ -z "$STARTUP" ] && [ ! -f "/dev/.in_sysinit" ] && return 0
	fi

	local found=
	local uname_r="$(uname -r)"

	for dir in /var/lib/dkms/$driver/*; do
		[ -e "$dir" ] || return 0 # no module, no build; or no /var
		[ -L "$dir" ] && continue # not a module version
		found=1 # module version found
		[ -e "$dir/$uname_r" ] && return 0
		[ -e "/var/lib/dkms-binary/$driver/$(basename "$dir")/$uname_r" ] && return 0

		if [ -e "$dir/build/make.log" ]; then
			# Build has failed for some kernel, check if it is this one.
			# If so, there is no point in returning 1.
			grep -q "^DKMS make\.log.* $uname_r " && return 0
		fi
	done

	# if module versions were found but none were built for this kernel, return 1
	[ -n "$found" ] && return 1 || return 0
}

# Note: no /usr
check_gl() {
	local alt_inode="$(stat -L -c%i $1 2>/dev/null)"
	[ -n "$alt_inode" ] || return 1
	[ -n "$GL_INODE" ] || GL_INODE="$(stat -L -c%i /etc/alternatives/gl_conf 2>/dev/null)"
	[ "$alt_inode" = "$GL_INODE" ] || return 1
	return 0
}

# Note: no /usr
get_xorg_drivers() {
	if [ -z "$XORG_DRIVERS" ]; then
		XORG_DRIVERS="$(cat /etc/X11/xorg.conf /etc/X11/xorg.conf.d/*.conf 2>/dev/null |
			awk -F'"' -vORS=' ' -vIGNORECASE=1 '
			/^[[:space:]]+*section[[:space:]]+"device"/	{ device=1 }
			/endsection/					{ device=0 }
			/^[[:space:]]*driver[[:space:]]*".*"/		{ if (device) drivers[$2]=$2 }
			END						{ for (driver in drivers) print driver }
			')"
		[ -n "$XORG_DRIVERS" ] || XORG_DRIVERS="-"
	fi
}

# Note: no /usr
# parameter 1: KMS module or xorg driver
# parameter 2: 1 - check if the driver is explicitely enabled
#              0 - check only for conflicts
check_xorg() {
	local driver="$1"
	local explicit_only="$2"

	eval local xorg_drivers=\"\$XORG_$driver\"
	[ -n "$xorg_drivers" ] || xorg_drivers="$driver"
	eval local conflicts=\"\$CONFLICTS_$driver\"

	get_xorg_drivers

	conflict_found=
	for enabled_driver in $XORG_DRIVERS; do
		for xorg_driver in $xorg_drivers; do
			[ "$enabled_driver" = "$xorg_driver" ] && return 0
		done

		# if the X.org driver can be loaded implicitely, check that
		# there are no conflicting drivers that override the driver
		if [ "$explicit_only" = "0" -a -z "$conflict_found" ]; then
			for conflict in vesa $conflicts; do
				if [ "$enabled_driver" = "$conflict" ]; then
				       conflict_found=1
				       continue 2
				       # continue loop to check for an explicit load
				fi
			done
		fi
	done

	# in case of a conflict, do not load the module
	[ -n "$conflict_found" ] && return 1

	# no driver is selected - don't load if explicit_only is 1
	[ "$explicit_only" = "1" ] && return 1

	# implicit load allowed; only load if there is evidence that this is
	# not a live cd or similar with automatic configuration occurring later
	# in the boot process (which might configure a driver conflicting with
	# the implicit driver, e.g. a proprietary one)
	# TODO: Could this be replaced with a more robust check?
	[ -e "/etc/X11/xorg.conf" ] || [ -e "/etc/sysconfig/harddrake2/kernels" ] ||
		[ -e "/etc/sysconfig/harddrake2/xorg" ] || [ -e "/boot/grub/menu.lst" ]
}

# Load the driver for the specified modalias, if configured.
# Note: no /usr
load_driver() {
	local modalias="$1"
	local modulename
	local load_default=1

	for modulename in $(/sbin/modprobe -Rq "$modalias"); do
		check_driver "$modulename"
		case $? in
		1)	# a driver which needs handling by this script matches
			# the modalias, but was not configured - do not run
			# the generic modprobe if no other drivers are
			# configured either
			load_default=
			continue
			;;
		2)	continue
			;;
		esac

		if [ -n "$IS_KMS" ]; then
			grep -q "^$modulename " /proc/modules && return 0
			echo "$modulename" > /dev/.late_kms 2>/dev/null
			# If NEEDS_LOAD_NOW is not set and plymouth is running,
			# skip loading the driver to avoid quitting plymouth.
			# The driver will be loaded later by X server itself.
			[ -z "$NEEDS_LOAD_NOW" ] && /bin/plymouth --ping 2>/dev/null && return 0
			/bin/plymouth quit 2>/dev/null
		fi
		/sbin/modprobe -b "$modulename" && return 0
	done

	# no specially handled modules were loaded, so load all modules normally
	# unless $load_default was set above
	[ -z "$load_default" ] || /sbin/modprobe -b "$modalias"
}

is_kms_allowed() {
	for driver in $KMS_DRIVERS; do
		# Check all drivers for conflicts only.
		check_xorg $driver 0 || return 1
	done
	return 0
}

get_initrd_kms_drivers() {
	local initrd="$1"

	local kms_drivers="$(echo "$KMS_DRIVERS" | tr " " "|")"
	zcat "$initrd" | cpio -t --quiet | sed -nr "s,.*/($kms_drivers)\.ko.*$,\1,p"
}

get_active_kms_drivers() {
	local kms_drivers=
	for device in $(grep -l 0x03 /sys/bus/pci/devices/0000\:0*/class); do
		[ -e "$device" ] || continue
		device="$(dirname $device)"
		[ -f "$device/modalias" ] || continue
		modalias="$(cat "$device/modalias")"
		for modulename in $(/sbin/modprobe -Rq "$modalias"); do
			IS_KMS=
			check_driver "$modulename" || continue
			[ -n "$IS_KMS" ] && echo $modulename
		done
	done
}

usage() {
	cat <<EOF
Usage: $0 action [arguments]

Known actions:

  --load MODALIAS
        Load drivers matching MODALIAS, checking that they are enabled and
        configured.

  --load-dkms-autoload MODNAME MODALIAS
        Same as --load, but assume MODNAME is built and correct so that
        checking dkms status is unnecessary.

  --is-disabled MODNAME
        Checks whether the driver corresponding to MODNAME is disabled (e.g.
        a conflicting driver is configured, etc.). Unknown MODNAMEs are
        considered not disabled.

  --is-enabled-kms MODNAME
        Checks whether the driver corresponding to MODNAME is enabled and
        MODNAME is a known KMS module. Note that drivers may be enabled even
        if there is no such hardware. This just checks that there are
        no conflicting drivers in use etc.

  --is-kms-allowed
        Checks whether it is ok to load KMS drivers in initrd. This returns
        a failure when a conflicting driver is set up (vesa or a proprietary
        one).

  --get-all-kms-drivers
        Get a list of the known KMS drivers.

  --get-active-kms-drivers
        Get a list of the known KMS drivers which are enabled and the hardware
        is present.

  --get-initrd-kms-drivers INITRD
        Get a list of the known KMS drivers in initrd INITRD.

  --check-dkms-status
        Checks if there are no pending DKMS builds for the currently enabled
        drivers.

  --check-loaded
        Checks that there are no disabled drivers loaded.

  --check-speedboot
        Does --check-dkms-status and --check-loaded.

  --check-loaded-strict
        As --check-loaded, and consider ambiguous cases (e.g. nvidia where
        we can't detect if the loaded driver has the correct version) as
        failure.
EOF
}

# clear global variables

# cache for check_gl()
GL_INODE=

# cache for check_xorg()
XORG_DRIVERS=

# The driver is a KMS enabled driver. This will cause the script to quit
# plymouth when a driver is loaded by --load and NEEDS_LOAD_NOW below is set.
# This is done as plymouth is still attached to the default framebuffer (the
# issues caused by not doing this don't seem to be fatal, though, but the
# display may be lost completely until plymouth eventually stops).
# There is no option in plymouth to "reload" a driver, it expects any KMS
# driver to be loaded be before starting it.
IS_KMS=

# This KMS driver needs to be loaded before X server starts, so load it now
# even if we have to shut down plymouth (see above).
NEEDS_LOAD_NOW=

# dkms module that was built when calling from DKMS
DKMS_AUTOLOAD_MODULE=

# Set by check_loaded() when it can't be sure that the correct driver is loaded
# (e.g. in case of the multiple proprietary nvidia drivers which all identify as
# "nvidia" in loaded modules list).
UNSURE=

case "$1" in
--load)
	load_driver "$2"
	;;
--load-dkms-autoload)
	DKMS_AUTOLOAD_MODULE="$2"
	load_driver "$3"
	;;
--is-disabled)
	check_driver "$2"
	[ $? -eq 1 ]
	# unknown (2) are not considered disabled :)
	;;
--is-enabled-kms)
	check_driver "$2" && [ -n "$IS_KMS" ]
	;;
--is-kms-allowed)
	is_kms_allowed
	;;
--check-dkms-status)
	check_dkms_status
	;;
--get-all-kms-drivers)
	echo $KMS_DRIVERS
	;;
--get-active-kms-drivers)
	get_active_kms_drivers
	;;
--get-initrd-kms-drivers)
	get_initrd_kms_drivers "$2"
	;;
--check-loaded)
	check_loaded
	;;
--check-loaded-strict)
	check_loaded && [ -z "$UNSURE" ]
	;;
--check-speedboot)
	check_dkms_status && check_loaded
	;;
*)
	usage
	;;
esac