#! /bin/sh
#
# This script is used to configure the linux kernel.
#
# It was inspired by the challenge in the original Configure script
# to ``do something better'', combined with the actual need to ``do
# something better'' because the old configure script wasn't flexible
# enough.
#
# Please send comments / questions / bug fixes to raymondc@microsoft.com.
#
#              ***** IMPORTANT COMPATIBILITY NOTE ****
# If configuration changes are made which might adversely effect 
# Menuconfig or xconfig, please notify the respective authors so that 
# those utilities can be updated in parallel.
#
# Menuconfig:  <roadcapw@titus.org>
# xconfig:     <apenwarr@foxnet.net>  <eric@aib.com>
#              ****************************************
#
# Each line in the config file is a command.
#
# 050793 - use IFS='@' to get around a bug in a pre-version of bash-1.13
# with an empty IFS.
#
# 030995 (storner@osiris.ping.dk) - added support for tri-state answers,
# for selecting modules to compile.
#
# 180995 Bernhard Kaindl (bkaindl@ping.at) - added dummy functions for
# use with a config.in modified for make menuconfig.
#
# 301195 (boldt@math.ucsb.edu) - added help text support
#
# 281295 Paul Gortmaker - make tri_state functions collapse to boolean
# if module support is not enabled.
#
# 010296 Aaron Ucko (ucko@vax1.rockhurst.edu) - fix int and hex to accept
# arbitrary ranges
#
# 150296 Dick Streefland (dicks@tasking.nl) - report new configuration
# items and ask for a value even when doing a "make oldconfig"
#
# 200396 Tom Dyas (tdyas@eden.rutgers.edu) - when the module option is
# chosen for an item, define the macro <option_name>_MODULE
#
# 090397 Axel Boldt (boldt@math.ucsb.edu) - avoid ? and + in regular 
# expressions for GNU expr since version 1.15 and up use \? and \+.

# 040697 Larry Augustin (lma@varesearch.com) - integer expr test
# fails with GNU expr 1.12. Re-write to work with new and old expr.

#
# Make sure we're really running bash.
#
# I would really have preferred to write this script in a language with
# better string handling, but alas, bash is the only scripting language
# that I can be reasonable sure everybody has on their linux machine.
#
[ -z "$BASH" ] && { echo "Configure requires bash" 1>&2; exit 1; }

# Disable filename globbing once and for all.
# Enable function cacheing.
set -f -h

#
# Dummy functions for use with a config.in modified for menuconf
#
function mainmenu_option () {
	:
}
function mainmenu_name () {
	:
}
function endmenu () {
	:
}

#
# help prints the corresponding help text from Configure.help to stdout
#
#       help variable
#
function help () {
  if [ -f Documentation/Configure.help ]
  then
     #first escape regexp special characters in the argument:
     var=$(echo "$1"|sed 's/[][\/.^$*]/\\&/g')
     #now pick out the right help text:
     text=$(sed -n "/^$var[ 	]*\$/,\${
			/^$var[ 	]*\$/b
			/^#.*/b
			/^[ 	]*\$/q
			p
		    }" Documentation/Configure.help)
     if [ -z "$text" ]
     then
	  echo; echo "  Sorry, no help available for this option yet.";echo
     else
	  (echo; echo "$text"; echo) | ${PAGER:-more}
     fi
  else
     echo;
     echo "  Can't access the file Documentation/Configure.help which"
     echo "  should contain the help texts."
     echo
  fi
}


#
# readln reads a line into $ans.
#
#	readln prompt default oldval
#
function readln () {
	if [ "$DEFAULT" = "-d" -a -n "$3" ]; then
		echo "$1"
		ans=$2
	else
		echo -n "$1"
		[ -z "$3" ] && echo -n "(NEW) "
		IFS='@' read ans </dev/tty || exit 1
		[ -z "$ans" ] && ans=$2
	fi
}

#
# comment does some pretty-printing
#
#	comment 'xxx'
# 
function comment () {
	echo "*"; echo "* $1" ; echo "*"
	(echo "" ; echo "#"; echo "# $1" ; echo "#") >>$CONFIG
	(echo "" ; echo "/*"; echo " * $1" ; echo " */") >>$CONFIG_H
}

#
# define_bool sets the value of a boolean argument
#
#	define_bool define value
#
function define_bool () {
	case "$2" in
	 "y")
		echo "$1=y" >>$CONFIG
		echo "#define $1 1" >>$CONFIG_H
		;;

	 "m")
		echo "$1=m" >>$CONFIG
		echo "#undef  $1" >>$CONFIG_H
		echo "#define $1_MODULE 1" >>$CONFIG_H
		;;

	 "n")
		echo "# $1 is not set" >>$CONFIG
		echo "#undef  $1" >>$CONFIG_H
		;;
	esac
	eval "$1=$2"
}

#
# bool processes a boolean argument
#
#	bool question define
#
function bool () {
	old=$(eval echo "\${$2}")
	def=${old:-'n'}
	case "$def" in
	 "y" | "m") defprompt="Y/n/?"
	      def="y"
	      ;;
	 "n") defprompt="N/y/?"
	      ;;
	esac
	while :; do
	  readln "$1 ($2) [$defprompt] " "$def" "$old"
	  case "$ans" in
	    [yY] | [yY]es ) define_bool "$2" "y"
			    break;;
	    [nN] | [nN]o )  define_bool "$2" "n"
			    break;;
	    * )             help "$2"
			    ;;
	  esac
	done
}

#
# tristate processes a tristate argument
#
#	tristate question define
#
function tristate () {
	if [ "$CONFIG_MODULES" != "y" ]; then
	  bool "$1" "$2"
	else 
	  old=$(eval echo "\${$2}")
	  def=${old:-'n'}
	  case "$def" in
	   "y") defprompt="Y/m/n/?"
		;;
	   "m") defprompt="M/n/y/?"
		;;
	   "n") defprompt="N/y/m/?"
		;;
	  esac
	  while :; do
	    readln "$1 ($2) [$defprompt] " "$def" "$old"
	    case "$ans" in
	      [yY] | [yY]es ) define_bool "$2" "y"
			      break ;;
	      [nN] | [nN]o )  define_bool "$2" "n"
			      break ;;
	      [mM] )          define_bool "$2" "m"
			      break ;;
	      * )             help "$2"
			      ;;
	    esac
	  done
	fi
}

#
# dep_tristate processes a tristate argument that depends upon
# another option.  If the option we depend upon is a module,
# then the only allowable options are M or N.  If Y, then
# this is a normal tristate.  This is used in cases where modules
# are nested, and one module requires the presence of something
# else in the kernel.
#
#	tristate question define default
#
function dep_tristate () {
	old=$(eval echo "\${$2}")
	def=${old:-'n'}
	if [ "$3" = "n" ]; then
		define_bool "$2" "n"
	elif [ "$3" = "y" ]; then
		tristate "$1" "$2"
	else
	   if [ "$CONFIG_MODULES" = "y" ]; then
		case "$def" in
		 "y" | "m") defprompt="M/n/?"
		      def="m"
		      ;;
		 "n") defprompt="N/m/?"
		      ;;
		esac
		while :; do
		  readln "$1 ($2) [$defprompt] " "$def" "$old"
		  case "$ans" in
		      [nN] | [nN]o )  define_bool "$2" "n"
				      break ;;
		      [mM] )          define_bool "$2" "m"
				      break ;;
		      [yY] | [yY]es ) echo 
   echo "  This answer is not allowed, because it is not consistent with"
   echo "  your other choices."
   echo "  This driver depends on another one which you chose to compile"
   echo "  as a module. This means that you can either compile this one"
   echo "  as a module as well (with M) or leave it out altogether (N)."
				      echo
				      ;;
		      * )             help "$2"
				      ;;
		  esac
		done
	   fi
	fi
}

#
# define_int sets the value of a integer argument
#
#	define_int define value
#
function define_int () {
	echo "$1=$2" >>$CONFIG
	echo "#define $1 ($2)" >>$CONFIG_H
	eval "$1=$2"
}

#
# int processes an integer argument
#
#	int question define default
# GNU expr changed handling of ?.  In older versions you need ?,
# in newer you need \?
OLD_EXPR=`expr "0" : '0\?'`
if [ $OLD_EXPR -eq 1 ]; then
    INT_EXPR='0$\|-\?[1-9][0-9]*$'
else
    INT_EXPR='0$\|-?[1-9][0-9]*$'
fi
function int () {
	old=$(eval echo "\${$2}")
	def=${old:-$3}
	while :; do
	  readln "$1 ($2) [$def] " "$def" "$old"
	  if expr "$ans" : $INT_EXPR > /dev/null; then
	    define_int "$2" "$ans"
	    break
	  else
	    help "$2"
	  fi
	done
}
#
# define_hex sets the value of a hexadecimal argument
#
#	define_hex define value
#
function define_hex () {
	echo "$1=$2" >>$CONFIG
	echo "#define $1 0x${2#*[x,X]}" >>$CONFIG_H
	eval "$1=$2"
}

#
# hex processes an hexadecimal argument
#
#	hex question define default
#
function hex () {
	old=$(eval echo "\${$2}")
	def=${old:-$3}
	def=${def#*[x,X]}
	while :; do
	  readln "$1 ($2) [$def] " "$def" "$old"
	  ans=${ans#*[x,X]}
	  if expr "$ans" : '[0-9a-fA-F][0-9a-fA-F]*$' > /dev/null; then
	    define_hex "$2" "$ans"
	    break
	  else
	    help "$2"
	  fi
	done
}

#
# choice processes a choice list (1-out-of-n)
#
#	choice question choice-list default
#
# The choice list has a syntax of:
#	NAME WHITESPACE VALUE { WHITESPACE NAME WHITESPACE VALUE }
# The user may enter any unique prefix of one of the NAMEs and
# choice will define VALUE as if it were a boolean option.
# VALUE must be in all uppercase.  Normally, VALUE is of the
# form CONFIG_<something>.  Thus, if the user selects <something>,
# the CPP symbol CONFIG_<something> will be defined and the
# shell variable CONFIG_<something> will be set to "y".
#
function choice () {
	question="$1"
	choices="$2"
	old=
	def=$3

	# determine default answer:
	names=""
	set -- $choices
	firstvar=$2
	while [ -n "$2" ]; do
		if [ -n "$names" ]; then
			names="$names, $1"
		else
			names="$1"
		fi
		if [ "$(eval echo \"\${$2}\")" = "y" ]; then
			old=$1
			def=$1
		fi
		shift; shift
	done

	val=""
	while [ -z "$val" ]; do
		ambg=n
		readln "$question ($names) [$def] " "$def" "$old"
		ans=$(echo $ans | tr a-z A-Z)
		set -- $choices
		while [ -n "$1" ]; do
			name=$(echo $1 | tr a-z A-Z)
			case "$name" in
				"$ans"* )
					if [ "$name" = "$ans" ]; then
						val="$2"
						break	# stop on exact match
					fi
					if [ -n "$val" ]; then
						echo;echo \
		"  Sorry, \"$ans\" is ambiguous; please enter a longer string."
						echo
						val=""
						ambg=y
						break
					else
						val="$2"
					fi;;
			esac
			shift; shift
		done
		if [ "$val" = "" -a "$ambg" = "n" ]; then
			help "$firstvar"
		fi
	done
	set -- $choices
	while [ -n "$2" ]; do
		if [ "$2" = "$val" ]; then
			echo "  defined $val"
			define_bool "$2" "y"
		else
			define_bool "$2" "n"
		fi
		shift; shift
	done
}

CONFIG=.tmpconfig
CONFIG_H=.tmpconfig.h
trap "rm -f $CONFIG $CONFIG_H ; exit 1" 1 2

#
# Make sure we start out with a clean slate.
#
echo "#" > $CONFIG
echo "# Automatically generated make config: don't edit" >> $CONFIG
echo "#" >> $CONFIG

echo "/*" > $CONFIG_H
echo " * Automatically generated C config: don't edit" >> $CONFIG_H
echo " */" >> $CONFIG_H
echo "#define AUTOCONF_INCLUDED" >> $CONFIG_H

DEFAULT=""
if [ "$1" = "-d" ] ; then
	DEFAULT="-d"
	shift
fi

CONFIG_IN=./config.in
if [ "$1" != "" ] ; then
	CONFIG_IN=$1
fi

DEFAULTS=arch/$ARCH/defconfig
if [ -f .config ]; then
  DEFAULTS=.config
fi

if [ -f $DEFAULTS ]; then
  echo "#"
  echo "# Using defaults found in" $DEFAULTS
  echo "#"
  . $DEFAULTS
  sed -e 's/# \(.*\) is not.*/\1=n/' < $DEFAULTS > .tmp.conf.$$
  . .tmp.conf.$$
  rm .tmp.conf.$$
else
  echo "#"
  echo "# No defaults found"
  echo "#"
fi

. $CONFIG_IN

rm -f .config.old
if [ -f .config ]; then
	mv .config .config.old
fi
mv .tmpconfig .config
mv .tmpconfig.h include/linux/autoconf.h

echo
echo "The linux kernel is now hopefully configured for your setup."
echo "Check the top-level Makefile for additional configuration,"
echo "and do a 'make dep ; make clean' if you want to be sure all"
echo "the files are correctly re-made"
echo

exit 0