#!/bin/sh

##########################################################
#File: mkdumprd2
#Author: Neil Horman <nhorman@redhat.com>
#Copyright 2009 Red Hat, Inc.
#Summary: A vastly simplified infrastructure for creating
#         initramfs files for use with kdump
#########################################################



########################################################
#Global Variables
########################################################
#BASE_DIR is the parent of both TEMP_DIR and STAGE_DIR
BASE_DIR=""

#TEMP_DIR is the directory where any temp files that we
#         create during the build process go, that we
#         do not want to wind up in our initramfs
TEMP_DIR=""

#STAGE_DIR is the directory we create to do all our
#          initramfs creation in
STAGE_DIR=""

#IMG_FILE is the file that is our initramfs after cpio
IMG_FILE=""

########################################################
#Cleanup functions so that we can get out easily and 
#sanely when something goes wrong
########################################################
finish_and_exit()
{
	local EXIT_CODE=$1
	local EXIT_MSG=$2

	if [ -n "$EXIT_MSG" ]
	then
		echo $EXIT_MSG
	fi
	exit $EXIT_CODE
}



#########################################################
#Clean up our various temporary files
#And exit
########################################################
cleanup_and_exit()
{
	EXIT_CODE=$1

	if [ -d $BASE_DIR ]
	then
		rm -rf $BASE_DIR
	fi

	if [ -f $IMG_FILE ]
	then
		rm -f $IMG_FILE
	fi
	
	finish_and_exit $EXIT_CODE $2 
}

#########################################################
# Setup appropriate environment things
#########################################################
setup_env()
{
	PATH=$PATH:/etc/kdump-adv-conf/kdump_build_helpers
}


#########################################################
# Handle sigint so we clean up well
#########################################################
handle_sigint()
{
	cleanup_and_exit 2 "Caught Sigint"
}


#########################################################
#Trap sigint so we can clean up
#########################################################
setup_traps()
{
	trap handle_sigint 2
}

#########################################################
#This creates the directory hierarchy that use to
#start creating a new initramfs
#########################################################
create_new_initramfs_dir()
{
	local TMPDIR=`mktemp -d`
	if [ ! -d $TMPDIR ]
	then
		return 1 
	fi

	mkdir $TMPDIR/stage
	mkdir $TMPDIR/temp

	BASE_DIR=$TMPDIR
	STAGE_DIR=$TMPDIR/stage
	TEMP_DIR=$TMPDIR/temp

	return 0
}


#########################################################
#Helper functions for stage_initramfs
#########################################################
create_initramfs_dirs()
{
	mkdir -p $STAGE_DIR/lib || return 1
	mkdir -p $STAGE_DIR/lib64 || return 1
	mkdir -p $STAGE_DIR/bin || return 1
	mkdir -p $STAGE_DIR/etc || return 1
	mkdir -p $STAGE_DIR/dev || return 1
	mkdir -p $STAGE_DIR/proc || return 1
	mkdir -p $STAGE_DIR/sys || return 1
	mkdir -p $STAGE_DIR/tmp || return 1
	mkdir -p $STAGE_DIR/sysroot || return 1
	mkdir -p $STAGE_DIR/modules || return 1
	mkdir -p $STAGE_DIR/usr/share/udhcpc || return 1
	mkdir -p $STAGE_DIR/var/run || return 1
	mkdir -p $STAGE_DIR/etc/network/if-pre-up.d || return 1
	mkdir -p $STAGE_DIR/etc/network/if-up.d || return 1
	mkdir -p $STAGE_DIR/etc/network/if-pre-down.d || return 1
	mkdir -p $STAGE_DIR/etc/network/if-down.d || return 1
	mkdir -p $STAGE_DIR/etc/network/if-post-down.d || return 1
	$(cd $STAGE_DIR; ln -s bin sbin)
}

load_dependent_libs()
{
	local BIN=$1
	ldd $BIN | grep -q "not a dynamic executable"
	if [ $? == 0 ]
	then
		#There are no dependencies, we're done
		return
	fi

	ldd $BIN | grep -q "statically linked"
	if [ $? == 0 ]
	then
		#There are no dependencies, we're done
		return
	fi

	for LIB in `ldd $BIN | awk '/\// {if ($2 == "=>") { print $3} else {print $1}}'`
	do
		load_dependent_libs $LIB
		if [ ! -f $STAGE_DIR/$LIB ]
		then
			install --mode=755 $LIB $STAGE_DIR/$LIB
		fi
	done
	return
}

install_with_deps()
{
	local BIN=$1
	local MODE=$2

	install --mode=$MODE $BIN $STAGE_DIR/bin
	load_dependent_libs $BIN 
}	

populate_std_files()
{
	# We of course need busybox
	install_with_deps /sbin/busybox 755

	# And we need to link all the apps busybox provides in
	for i in `/sbin/busybox | 
		awk 'BEGIN {found=0} /.*/ { if (found) print $0 } /Currently/ {found=1}' | 
		sed -e's/,//g' -e's/busybox//g'`
	do
		ln -s busybox $STAGE_DIR/sbin/$i
	done

	# We always get kpartx, dmsetup, lvm and mdadm
	for i in /sbin/lvm /sbin/kpartx /sbin/mdadm /sbin/dmsetup
	do
		install_with_deps $i 755
	done

	# We also want to suck in all the runtime scripts 
	# that make life easier inside the initramfs
	# These don't need deps, because they're all msh scripts
	for i in `ls /etc/kdump-adv-conf/kdump_build_helpers/`
	do
		if [ -f $i ]
		then
			install --mode=755 $i $STAGE_DIR/bin
		fi
	done

}

#########################################################
#This function is the recepie for populating our initramfs
#with the basic included functions/scripts, loading the 
#manifest files, copying in the init script, and doing
#site specific post processing
#########################################################
prep_std_initramfs()
{
	#start by creating the directories we need
	create_initramfs_dirs

	#copy in the standard included files 
	populate_std_files
}


##########################################################
#This function validates each line in the manifest file to 
#ensure that we sanitize the input
#Args are:
#1 - file type
#2 - File source
#3 - destination path
#4 - optional arguments
##########################################################
validate_manifest_line()
{

	case "$1" in
	reg|ren)
		# Regular file, make sure that the file exists
		if [ ! -f $2 ]
		then
			return 1
		fi
		;;
	gen)
		# Generated file, make sure that the script
		# exists and is executable
		TEST_BIN=$(which $2)
		if [ ! -x $TEST_BIN ]
		then
			return 1
		fi
		;;
	exec)
		# exec files have no output, they simply
		# provide a means by which to manipulate the
		# the initramfs.  Just make sure the file exists
		TEST_BIN=$(which $2)
		if [ ! -x $TEST_BIN ]
		then
			return 1
		fi
		;;
	*)
		echo $1 | grep -q "^#"
		if [ $? -eq 0 ]
		then
			# its a comment
			continue
		fi
		# Unknown manifest type, fail
		return 1
		;;
	esac

	return 0
}

##########################################################
#This function reads in our manifest file and moves all 
#the specified contents to their respective destinations
#the manifest file has the following format
#
#{type} {source arg} {dest path}
#
#see the kexec-adv-manifest man page for details
##########################################################
populate_from_manifest()
{
	local type
	local sarg
	local dpath
	local opts
	local ddir

	while read type sarg dpath opts
	do
		validate_manifest_line $type $sarg $dpath $opts
		if [ $? != 0 ]
		then
			cleanup_and_exit 1 "$sarg: Invalid line in manifest"
		fi

		case "$type" in
		reg|ren)
			# Just do a raw copy from the source path
			# to the dest path
			if [ "$type" == "reg" ]
			then
				ddir=$STAGE_DIR/$dpath
			else
				ddir=$(dirname $STAGE_DIR/$dpath)
			fi
			mkdir -p $ddir
			cp $sarg $STAGE_DIR/$dpath	
			;;
		gen)
			# Generated file: run the sarg with the provided opts
			# Assume that the binary will output the generated file
			# to stdout
			ddir=$(dirname $STAGE_DIR/$dpath)
			mkdir -p $ddir
			$sarg $opts > $STAGE_DIR/$dpath
			if [ $? != 0 ]
			then
				cleanup_and_exit 1 "$sarg: Non-zero exit"
			fi
			;;
		exec)
			# Just run $sarg as program, passing $BASE_DIR as the
			# first argument, and $opts next.  This lets us
			# manipulate the intiramfs without having to add
			# anything to the file
			$sarg $BASE_DIR $opts
			if [ $? != 0 ]
			then
				cleanup_and_exit 1 "$sarg: Non-zero exit"
			fi

		esac
	done < /etc/kdump-adv-conf/manifest
}


##########################################################
# This function takes our stage directory, and makes an 
# image file out of it
##########################################################
create_initramfs_image()
{
	IMG_FILE=$(mktemp $TEMP_DIR/initrd.img.XXXXXX)
	(cd $STAGE_DIR; find . | cpio --quiet -c -o) > $IMG_FILE
	if [ $? != 0 ]
	then
		cleanup_and_exit 1 " Could not create initramfs"
	fi

	# Get running kernel version to name the initramfs with
	target=$(uname -r)
	gzip -9 -c $IMG_FILE > ./initrd-$target.img
}


##########################################################
#Start the actual code here
##########################################################

# Get our passed in options

#setup working env
setup_env
setup_traps

# Create a new staging area
create_new_initramfs_dir
if [ $? != 0 ]
then
	cleanup_and_exit 1 "Unable to stage a new initramfs area"
fi

# Do staging
prep_std_initramfs

# Pull in the user supplied manifest
populate_from_manifest

# Do image file creation
create_initramfs_image

# Cleanup
cleanup_and_exit 0 ""