#!/bin/sh
#
# altboot provides a simple bootmenu before init is beeing run.
# There are two default menu entries: "Normal boot" and "Single user mode"
# New menu entries can be created be putting files into /etc/altboot-menu.
#

test -e /etc/altboot.func && . /etc/altboot.func || die "ERROR: /etc/altboot.func not found. Check your installation!"

CURRENT_ENV="`set`"
VERSION="0.0.4"

# Set some defaults in case altboot.cfg is missing
REAL_INIT="/sbin/init.sysvinit"

# Read default runlevel from inittab
INIT_RUNLEVEL="`cat /etc/inittab | sed -n "/^id\:/s/id\:\([0-9]\)\:.*$/\1/p"`"
test -z "$INIT_RUNLEVEL" && INIT_RUNLEVEL=5

case "`uname -r`" in
2.6*)	ALTBOOT_CFG_FILE="/etc/altboot-2.6.cfg";;
2.4*)	ALTBOOT_CFG_FILE="/etc/altboot-2.4.cfg";;
*)	echo "Warning: Unknown kernel [`uname -r`], using kernel 2.6 configuration!"
	ALTBOOT_CFG_FILE="/etc/altboot-2.6.cfg";;
esac

test -e "$ALTBOOT_CFG_FILE" && . "$ALTBOOT_CFG_FILE" || echo "WARNING: No $ALTBOOT_CFG_FILE found! Check your installation of Altboot!" > /dev/tty1

C_RED="\033[31m"
C_BLUE="\033[34m"
C_WHITE="\033[37m"
C_RESET="\033[0m"

die() {
	echo "ERROR: $1" >/dev/tty0
	#exec $SH_SHELL </dev/tty0 >/dev/tty0 2>&1
	
	echo -e "\nPress <ENTER> to launch the altboot menu"
	read junk
	exec /sbin/init.altboot -force</dev/tty0 >/dev/tty0 2>&1
}


# This function prints the boot-menu
# $1: Directory containing the scripts for the menu-items
show_menu() {
	test -z "$1" && die "DEBUG: Parameter 1 is empty in show_menu"
	echo "" 
	echo -e "altboot v$VERSION\n" 

	cnt=0
	m_entry=""
	if test -d $1
	then
		# Build "m_entry" for scripts in /etc/altboot-menu
		cd $1
		for file in `ls -1`
		do	
			if ! test -d "$1/$file"
			then			
				M_TITLE="`$1/$file title`"
				if ! test -z "$M_TITLE"
				then
					let cnt=$cnt+1
					# Keep a list of existing "modules" together with an index number
					# This sure is ugly, but Busybox sh doesn't do arrays....
					m_entry="`echo -e "$m_entry\n$cnt:$file\n"`"
					echo -e "\t\t[$cnt] $M_TITLE"					
				fi
				M_TITLE=""
			fi
		done

		# Display directories below /etc/altboot-menu as menu-item
		# and add all scripts inside the directory to m_entry
		for dir in `ls -1`
		do	
			if test -d "$1/$dir"
			then			
				M_TITLE="`basename "$1/$dir"`"
				if ! test -z "$M_TITLE"
				then
					let cnt=$cnt+1
					# Keep a list of existing "modules" together with an index number
					# This sure is ugly, but Busybox sh doesn't do arrays....
					m_entry="`echo -e "$m_entry\n$cnt:$dir:DIR\n"`"
					echo -e "\t\t[$cnt] $M_TITLE"					
					
					OLD_PWD="$PWD"
					cd "$1/$dir"
					for file in `ls -1`
					do	
						if ! test -d "$1/$dir/$file"
						then			
							M_TITLE="`$1/$dir/$file title`"
							if ! test -z "$M_TITLE"
							then
								let cnt=$cnt+1
								# Keep a list of existing "modules" together with an index number
								# This sure is ugly, but Busybox sh doesn't do arrays....
								m_entry="`echo -e "$m_entry\n$cnt:$dir/$file\n"`"
								#echo -e "\t\t[$cnt] $M_TITLE"					
							fi
							M_TITLE=""
						fi
					done
					cd "$OLD_PWD"

				fi
				M_TITLE=""
			fi
		done
		
		
		echo ""
	else
		echo "WARNING: $1 not found"
	fi
	
}

# This function is used to display the content of directories below
# /etc/altboot-menu as menu-items
show_sub_menu() {
	dirname="`basename "$1"`"
		
	d_entries="`echo "$m_entry"|grep "$dirname/"`"
	
#	echo "[$d_entries]"
	
	echo -e "\naltboot v$VERSION: $dirname menu\n" 
	
	
	for d_entry in $d_entries
	do
		d_entry_number="`echo "$d_entry"| sed -n "s/\(.*\)\:\(.*\)/\1/p"`"
		d_entry_file="`echo "$d_entry"| sed -n "s/\(.*\)\:\(.*\)/\2/p"`"
		d_entry_title="`$d_entry_file title`"
		
#		echo "number: [$d_entry_number]"
#		echo "file: [$d_entry_file]"
#		echo "title: [$d_entry_title]"
		
		echo -e "\t\t[$d_entry_number] $d_entry_title"
	done
		
	echo ""
	
}

# Shows the timer and sets $launch_altboot to yes if a keypress was detected
run_timer() {
	if test "$TIMEOUT" != 0
	then
			
		mount -t proc proc /proc >/dev/null 2>&1
		
		case "`uname -r`" in
		2.4*)	key_ints="`cat /proc/interrupts | grep keyboard | awk '{print $2}'`";;
		2.6*)	key_ints="`cat /proc/interrupts | grep Spitzkbd`";;	
		esac		
	
		stty -echo
		echo -en "\n\nPlease press any key to launch altboot." > /dev/tty1
		
		test -z "$TIMEOUT" && TIMEOUT="3"

		cnt=0
		while test "$cnt" != "$TIMEOUT"
		do		
			sleep 1
			case "`uname -r`" in
			2.4*)	key_ints_now="`cat /proc/interrupts | grep keyboard | awk '{print $2}'`";;
			2.6*)	key_ints_now="`cat /proc/interrupts | grep Spitzkbd`";;	
			esac		
			
			if test "$key_ints_now" != "$key_ints" 
			then				
				launch_altboot=yes				
				stty echo
				break
			fi
			echo -n "." >/dev/tty1
			let cnt=$cnt+1
		done
	else
		launch_altboot=yes
	fi
} 

# This function launches the selected menu item / script
# $1: Directory containing the scripts for the menu-items
launch_selection() {
	test -z "$1" && die "Parameter 1 of launch_selection is empty!"
	
	case "$junk" in
	*)	file="`echo "$m_entry"| sed -n "/$junk\:/s/^.*\:\(.*\)/\1/p"`"
		
		# The selected menu-item points to a directory
		if test "$file" = DIR
		then
			dir="`echo "$m_entry"| sed -n "/$junk\:/s/^.*\:\(.*\)\:\(.*\)/\1/p"`"
			show_sub_menu /etc/altboot-menu/$dir >/dev/tty0
			wait_for_input >/dev/tty0			
			launch_selection /etc/altboot-menu >/dev/tty0						
		fi
		
		if test "$file" = MAIN
		then
			show_sub_menu /etc/altboot-menu >/dev/tty0
			wait_for_input >/dev/tty0			
			launch_selection /etc/altboot-menu >/dev/tty0						
		fi	
		
		#echo "[$file]"
				
		. $1/$file run "$file" >/dev/tty0	
		die "WARNING: Using failsafe shell" >/dev/tty0			
		
		;;	
	esac
}


wait_for_input() {
	while true
	do
		
		
		# Do _not_ change the next few lines!
		# 	
		# This is required to work around an annoying busybox bug.
		# Every key you press while this script runs will be
		# picked up by the next "read $junk".	
		# So the next read would pick up the "any" key the user pressed
		# above to launch the altboot menu.		
				
 		
		# This filters an "<ENTER>" from the user as "any key"
		( while :; do read x< /dev/tty0 2>&1; done; ) > /dev/null 2>&1 &
		sleep 1; kill $!
				
		

		echo -n "Please choose one of the above [$last_selection]: " </dev/tty0 > /dev/tty0 2>&1
		read junk< /dev/tty0 2>&1
		
		# This filters other chars the user may have used
		junk="`echo "$junk" |  sed -n "s/.*\([0-9]\)/\1/p"`"
		
		if test "$junk" -lt "$cnt" -o "$junk" -eq "$cnt" 
		then
			if test ! -z "$junk"
			then
				# Don't remount rw if the drive is already mounted rw
				# Only helpful for testing / debugging
				if test "`mount|sed -n "/\/dev\/root/s/.*(\(.*\))/\1/p"`" != "rw"
				then
					
					mount -o remount,rw / >/dev/null 2>&1
					echo "$junk" > /etc/altboot.conf
					mount -o remount,ro / >/dev/null 2>&1	
				else
					echo "$junk" > /etc/altboot.conf
				fi
			else
				junk="$last_selection"
				break
			fi
			break
		fi
	done
}

# * * * * * * This is the main function * * * * * *

if test "`runlevel`" != "unknown" -a "$1" != "-force"
then
	echo "altboot: Using real init [$REAL_INIT] [$*] *" >/dev/tty1
	exec $REAL_INIT $*
	exit 0
else	
	# Boot original init if altboot is turned off
	if test "$ENABLE_ALTBOOT" != "yes" 
	then	
		echo "altboot: Using real init [$REAL_INIT] **" >/dev/tty1
		exec $REAL_INIT $INIT_RUNLEVEL
		exit 0
	fi

	# Execute scripts in /etc/altboot.rc before doing anything else.
	# Required in special situations, like booting spitz
	RC_FILES=`ls /etc/altboot.rc | grep \.sh$`

	for file in $RC_FILES
	do
		 . /etc/altboot.rc/$file >/dev/tty1 2>&1 || echo "/etc/altboot.rc/$file failed!"
	done
		
	# Make sure altboots master password is set
	set_password >/dev/tty0 
	
	test "$ASK_PW_ON_BOOT" = "yes" && verify_master_pw >/dev/tty0 


	# When started with -force, always print the menu
	echo "$*" | grep -q -- "-force" && TIMEOUT=0

	
	# This timeout works by reading /proc/interrupts to see if the keyboard interrupt
	# increases while the timer is running. A TIMEOUT of 0 will always launch altboot.	
	run_timer >/dev/tty1 2>&1

		
	echo "" >/dev/tty0
	
	
	if test "$launch_altboot" != yes
	then
		# last_selection is the previously selected menu item by the user
		last_selection="`cat /etc/altboot.conf`" >/dev/null 2>&1
		test -z "$last_selection" && last_selection="1"	
		
		echo "Booting last selection: [$last_selection]" >/dev/tty0
		
		# Set up the wanna-be array of available menu entries and their numbers
		show_menu /etc/altboot-menu >/dev/null
		junk="$last_selection"
		launch_selection /etc/altboot-menu >/dev/tty0

	fi
	# Anything after this point will never be reached if $launch_altboot != yes
	
	# Show the altboot menu
	show_menu /etc/altboot-menu >/dev/tty0

	# Load last selection for use as default if <ENTER> is pressed at the prompt
	last_selection="`cat /etc/altboot.conf`" >/dev/null 2>&1
	test -z "$last_selection" && last_selection="1"	

	# Ask the user which menu-item to use
	wait_for_input >/dev/tty0 
	
	# This should _never_ happen.
	if test -z "$junk"
	then
		echo "WARNING: Trying failsafe mode" >/dev/tty0
		mount -o remount,rw / >/dev/tty0 2>&1
		echo "Dumping environment to /altboot.env"
		echo "$CURRENT_ENV" > /altboot.env
		mount -o remount,ro / >/dev/tty0 2>&1
		junk=1
	fi

	launch_selection /etc/altboot-menu >/dev/tty0	
	
	# Uhoh, something went terribly wrong if we reach this point!
	die "WARNING: Failsafe fall-through activated. Spawning emergency shell"	

fi