scripts/kconfig/streamline_config.pl - linux - Git at Google

 #!/usr/bin/env perl
 # SPDX-License-Identifier: GPL-2.0
 #
 # Copyright 2005-2009 - Steven Rostedt
 #
 #  It's simple enough to figure out how this works.
 #  If not, then you can ask me at stripconfig@goodmis.org
 #
 # What it does?
 #
 #   If you have installed a Linux kernel from a distribution
 #   that turns on way too many modules than you need, and
 #   you only want the modules you use, then this program
 #   is perfect for you.
 #
 #   It gives you the ability to turn off all the modules that are
 #   not loaded on your system.
 #
 # Howto:
 #
 #  1. Boot up the kernel that you want to stream line the config on.
 #  2. Change directory to the directory holding the source of the
 #       kernel that you just booted.
 #  3. Copy the configuration file to this directory as .config
 #  4. Have all your devices that you need modules for connected and
 #      operational (make sure that their corresponding modules are loaded)
 #  5. Run this script redirecting the output to some other file
 #       like config_strip.
 #  6. Back up your old config (if you want too).
 #  7. copy the config_strip file to .config
 #  8. Run "make oldconfig"
 #
 #  Now your kernel is ready to be built with only the modules that
 #  are loaded.
 #
 # Here's what I did with my Debian distribution.
 #
 #    cd /usr/src/linux-2.6.10
 #    cp /boot/config-2.6.10-1-686-smp .config
 #    ~/bin/streamline_config > config_strip
 #    mv .config config_sav
 #    mv config_strip .config
 #    make oldconfig
 #
 use warnings;
 use strict;
 use Getopt::Long;

 # set the environment variable LOCALMODCONFIG_DEBUG to get
 # debug output.
 my $debugprint = 0;
 $debugprint = 1 if (defined($ENV{LOCALMODCONFIG_DEBUG}));

 sub dprint {
     return if (!$debugprint);
     print STDERR @_;
 }

 my $uname = `uname -r`;
 chomp $uname;

 my @searchconfigs = (
 	{
 	    "file" => ".config",
 	    "exec" => "cat",
 	},
 	{
 	    "file" => "/proc/config.gz",
 	    "exec" => "zcat",
 	},
 	{
 	    "file" => "/boot/config-$uname",
 	    "exec" => "cat",
 	},
 	{
 	    "file" => "/boot/vmlinuz-$uname",
 	    "exec" => "scripts/extract-ikconfig",
 	    "test" => "scripts/extract-ikconfig",
 	},
 	{
 	    "file" => "vmlinux",
 	    "exec" => "scripts/extract-ikconfig",
 	    "test" => "scripts/extract-ikconfig",
 	},
 	{
 	    "file" => "/lib/modules/$uname/kernel/kernel/configs.ko",
 	    "exec" => "scripts/extract-ikconfig",
 	    "test" => "scripts/extract-ikconfig",
 	},
 	{
 	    "file" => "kernel/configs.ko",
 	    "exec" => "scripts/extract-ikconfig",
 	    "test" => "scripts/extract-ikconfig",
 	},
 	{
 	    "file" => "kernel/configs.o",
 	    "exec" => "scripts/extract-ikconfig",
 	    "test" => "scripts/extract-ikconfig",
 	},
 );

 sub read_config {
     foreach my $conf (@searchconfigs) {
 	my $file = $conf->{"file"};

 	next if ( ! -f "$file");

 	if (defined($conf->{"test"})) {
 	    `$conf->{"test"} $conf->{"file"} 2>/dev/null`;
 	    next if ($?);
 	}

 	my $exec = $conf->{"exec"};

 	print STDERR "using config: '$file'\n";

 	open(my $infile, '-|', "$exec $file") || die "Failed to run $exec $file";
 	my @x = <$infile>;
 	close $infile;
 	return @x;
     }
     die "No config file found";
 }

 my @config_file = read_config;

 # Parse options
 my $localmodconfig = 0;
 my $localyesconfig = 0;

 GetOptions("localmodconfig" => \$localmodconfig,
 	   "localyesconfig" => \$localyesconfig);

 # Get the build source and top level Kconfig file (passed in)
 my $ksource = ($ARGV[0] ? $ARGV[0] : '.');
 my $kconfig = $ARGV[1];
 my $lsmod_file = $ENV{'LSMOD'};

 my @makefiles = `find $ksource -name Makefile -or -name Kbuild 2>/dev/null`;
 chomp @makefiles;

 my %depends;
 my %selects;
 my %prompts;
 my %objects;
 my %config2kfile;
 my $var;
 my $iflevel = 0;
 my @ifdeps;

 # prevent recursion
 my %read_kconfigs;

 sub read_kconfig {
     my ($kconfig) = @_;

     my $state = "NONE";
     my $config;

     my $cont = 0;
     my $line;

     my $source = "$ksource/$kconfig";
     my $last_source = "";

     # Check for any environment variables used
     while ($source =~ /\$\((\w+)\)/ && $last_source ne $source) {
 	my $env = $1;
 	$last_source = $source;
 	$source =~ s/\$\($env\)/$ENV{$env}/;
     }

     open(my $kinfile, '<', $source) || die "Can't open $kconfig";
     while (<$kinfile>) {
 	chomp;

 	# Make sure that lines ending with \ continue
 	if ($cont) {
 	    $_ = $line . " " . $_;
 	}

 	if (s/\\$//) {
 	    $cont = 1;
 	    $line = $_;
 	    next;
 	}

 	$cont = 0;

 	# collect any Kconfig sources
 	if (/^source\s+"?([^"]+)/) {
 	    my $kconfig = $1;
 	    # prevent reading twice.
 	    if (!defined($read_kconfigs{$kconfig})) {
 		$read_kconfigs{$kconfig} = 1;
 		read_kconfig($kconfig);
 	    }
 	    next;
 	}

 	# configs found
 	if (/^\s*(menu)?config\s+(\S+)\s*$/) {
 	    $state = "NEW";
 	    $config = $2;
 	    $config2kfile{"CONFIG_$config"} = $kconfig;

 	    # Add depends for 'if' nesting
 	    for (my $i = 0; $i < $iflevel; $i++) {
 		if ($i) {
 		    $depends{$config} .= " " . $ifdeps[$i];
 		} else {
 		    $depends{$config} = $ifdeps[$i];
 		}
 		$state = "DEP";
 	    }

 	# collect the depends for the config
 	} elsif ($state eq "NEW" && /^\s*depends\s+on\s+(.*)$/) {
 	    $state = "DEP";
 	    $depends{$config} = $1;
 	} elsif ($state eq "DEP" && /^\s*depends\s+on\s+(.*)$/) {
 	    $depends{$config} .= " " . $1;
 	} elsif ($state eq "DEP" && /^\s*def(_(bool|tristate)|ault)\s+(\S.*)$/) {
 	    my $dep = $3;
 	    if ($dep !~ /^\s*(y|m|n)\s*$/) {
 		$dep =~ s/.*\sif\s+//;
 		$depends{$config} .= " " . $dep;
 		dprint "Added default depends $dep to $config\n";
 	    }

 	# Get the configs that select this config
 	} elsif ($state ne "NONE" && /^\s*select\s+(\S+)/) {
 	    my $conf = $1;
 	    if (defined($selects{$conf})) {
 		$selects{$conf} .= " " . $config;
 	    } else {
 		$selects{$conf} = $config;
 	    }

 	# configs without prompts must be selected
 	} elsif ($state ne "NONE" && /^\s*(tristate\s+\S|prompt\b)/) {
 	    # note if the config has a prompt
 	    $prompts{$config} = 1;

 	# Check for if statements
 	} elsif (/^if\s+(.*\S)\s*$/) {
 	    my $deps = $1;
 	    # remove beginning and ending non text
 	    $deps =~ s/^[^a-zA-Z0-9_]*//;
 	    $deps =~ s/[^a-zA-Z0-9_]*$//;

 	    my @deps = split /[^a-zA-Z0-9_]+/, $deps;

 	    $ifdeps[$iflevel++] = join ':', @deps;

 	} elsif (/^endif/) {

 	    $iflevel-- if ($iflevel);

 	# stop on "help" and keywords that end a menu entry
 	} elsif (/^\s*(---)?help(---)?\s*$/ || /^(comment|choice|menu)\b/) {
 	    $state = "NONE";
 	}
     }
     close($kinfile);
 }

 if ($kconfig) {
     read_kconfig($kconfig);
 }

 # Makefiles can use variables to define their dependencies
 sub convert_vars {
     my ($line, %vars) = @_;

     my $process = "";

     while ($line =~ s/^(.*?)(\$\((.*?)\))//) {
 	my $start = $1;
 	my $variable = $2;
 	my $var = $3;

 	if (defined($vars{$var})) {
 	    $process .= $start . $vars{$var};
 	} else {
 	    $process .= $start . $variable;
 	}
     }

     $process .= $line;

     return $process;
 }

 # Read all Makefiles to map the configs to the objects
 foreach my $makefile (@makefiles) {

     my $line = "";
     my %make_vars;

     open(my $infile, '<', $makefile) || die "Can't open $makefile";
     while (<$infile>) {
 	# if this line ends with a backslash, continue
 	chomp;
 	if (/^(.*)\\$/) {
 	    $line .= $1;
 	    next;
 	}

 	$line .= $_;
 	$_ = $line;
 	$line = "";

 	my $objs;

 	# Convert variables in a line (could define configs)
 	$_ = convert_vars($_, %make_vars);

 	# collect objects after obj-$(CONFIG_FOO_BAR)
 	if (/obj-\$\((CONFIG_[^\)]*)\)\s*[+:]?=\s*(.*)/) {
 	    $var = $1;
 	    $objs = $2;

 	# check if variables are set
 	} elsif (/^\s*(\S+)\s*[:]?=\s*(.*\S)/) {
 	    $make_vars{$1} = $2;
 	}
 	if (defined($objs)) {
 	    foreach my $obj (split /\s+/,$objs) {
 		$obj =~ s/-/_/g;
 		if ($obj =~ /(.*)\.o$/) {
 		    # Objects may be enabled by more than one config.
 		    # Store configs in an array.
 		    my @arr;

 		    if (defined($objects{$1})) {
 			@arr = @{$objects{$1}};
 		    }

 		    $arr[$#arr+1] = $var;

 		    # The objects have a hash mapping to a reference
 		    # of an array of configs.
 		    $objects{$1} = \@arr;
 		}
 	    }
 	}
     }
     close($infile);
 }

 my %modules;
 my $linfile;

 if (defined($lsmod_file)) {
     if ( ! -f $lsmod_file) {
 	if ( -f $ENV{'objtree'}."/".$lsmod_file) {
 	    $lsmod_file = $ENV{'objtree'}."/".$lsmod_file;
 	} else {
 		die "$lsmod_file not found";
 	}
     }

     my $otype = ( -x $lsmod_file) ? '-|' : '<';
     open($linfile, $otype, $lsmod_file);

 } else {

     # see what modules are loaded on this system
     my $lsmod;

     foreach my $dir ( ("/sbin", "/bin", "/usr/sbin", "/usr/bin") ) {
 	if ( -x "$dir/lsmod" ) {
 	    $lsmod = "$dir/lsmod";
 	    last;
 	}
     }
     if (!defined($lsmod)) {
 	# try just the path
 	$lsmod = "lsmod";
     }

     open($linfile, '-|', $lsmod) || die "Can not call lsmod with $lsmod";
 }

 while (<$linfile>) {
 	next if (/^Module/);  # Skip the first line.
 	if (/^(\S+)/) {
 		$modules{$1} = 1;
 	}
 }
 close ($linfile);

 # add to the configs hash all configs that are needed to enable
 # a loaded module. This is a direct obj-${CONFIG_FOO} += bar.o
 # where we know we need bar.o so we add FOO to the list.
 my %configs;
 foreach my $module (keys(%modules)) {
     if (defined($objects{$module})) {
 	my @arr = @{$objects{$module}};
 	foreach my $conf (@arr) {
 	    $configs{$conf} = $module;
 	    dprint "$conf added by direct ($module)\n";
 	    if ($debugprint) {
 		my $c=$conf;
 		$c =~ s/^CONFIG_//;
 		if (defined($depends{$c})) {
 		    dprint " deps = $depends{$c}\n";
 		} else {
 		    dprint " no deps\n";
 		}
 	    }
 	}
     } else {
 	# Most likely, someone has a custom (binary?) module loaded.
 	print STDERR "$module config not found!!\n";
     }
 }

 # Read the current config, and see what is enabled. We want to
 # ignore configs that we would not enable anyway.

 my %orig_configs;
 my $valid = "A-Za-z_0-9";

 foreach my $line (@config_file) {
     $_ = $line;

     if (/(CONFIG_[$valid]*)=(m|y)/) {
 	$orig_configs{$1} = $2;
     }
 }

 my $repeat = 1;

 my $depconfig;

 #
 # Note, we do not care about operands (like: &&, ||, !) we want to add any
 # config that is in the depend list of another config. This script does
 # not enable configs that are not already enabled. If we come across a
 # config A that depends on !B, we can still add B to the list of depends
 # to keep on. If A was on in the original config, B would not have been
 # and B would not be turned on by this script.
 #
 sub parse_config_depends
 {
     my ($p) = @_;

     while ($p =~ /[$valid]/) {

 	if ($p =~ /^[^$valid]*([$valid]+)/) {
 	    my $conf = "CONFIG_" . $1;

 	    $p =~ s/^[^$valid]*[$valid]+//;

 	    # We only need to process if the depend config is a module
 	    if (!defined($orig_configs{$conf}) || $orig_configs{$conf} eq "y") {
 		next;
 	    }

 	    if (!defined($configs{$conf})) {
 		# We must make sure that this config has its
 		# dependencies met.
 		$repeat = 1; # do again
 		dprint "$conf selected by depend $depconfig\n";
 		$configs{$conf} = 1;
 	    }
 	} else {
 	    die "this should never happen";
 	}
     }
 }

 # Select is treated a bit differently than depends. We call this
 # when a config has no prompt and requires another config to be
 # selected. We use to just select all configs that selected this
 # config, but found that that can balloon into enabling hundreds
 # of configs that we do not care about.
 #
 # The idea is we look at all the configs that select it. If one
 # is already in our list of configs to enable, then there's nothing
 # else to do. If there isn't, we pick the first config that was
 # enabled in the original config and use that.
 sub parse_config_selects
 {
     my ($config, $p) = @_;

     my $next_config;

     while ($p =~ /[$valid]/) {

 	if ($p =~ /^[^$valid]*([$valid]+)/) {
 	    my $conf = "CONFIG_" . $1;

 	    $p =~ s/^[^$valid]*[$valid]+//;

 	    # Make sure that this config exists in the current .config file
 	    if (!defined($orig_configs{$conf})) {
 		dprint "$conf not set for $config select\n";
 		next;
 	    }

 	    # Check if something other than a module selects this config
 	    if (defined($orig_configs{$conf}) && $orig_configs{$conf} ne "m") {
 		dprint "$conf (non module) selects config, we are good\n";
 		# we are good with this
 		return;
 	    }
 	    if (defined($configs{$conf})) {
 		dprint "$conf selects $config so we are good\n";
 		# A set config selects this config, we are good
 		return;
 	    }
 	    # Set this config to be selected
 	    if (!defined($next_config)) {
 		$next_config = $conf;
 	    }
 	} else {
 	    die "this should never happen";
 	}
     }

     # If no possible config selected this, then something happened.
     if (!defined($next_config)) {
 	print STDERR "WARNING: $config is required, but nothing in the\n";
 	print STDERR "  current config selects it.\n";
 	return;
     }

     # If we are here, then we found no config that is set and
     # selects this config. Repeat.
     $repeat = 1;
     # Make this config need to be selected
     $configs{$next_config} = 1;
     dprint "$next_config selected by select $config\n";
 }

 my %process_selects;

 # loop through all configs, select their dependencies.
 sub loop_depend {
     $repeat = 1;

     while ($repeat) {
 	$repeat = 0;

       forloop:
 	foreach my $config (keys %configs) {

 	    # If this config is not a module, we do not need to process it
 	    if (defined($orig_configs{$config}) && $orig_configs{$config} ne "m") {
 		next forloop;
 	    }

 	    $config =~ s/^CONFIG_//;
 	    $depconfig = $config;

 	    if (defined($depends{$config})) {
 		# This config has dependencies. Make sure they are also included
 		parse_config_depends $depends{$config};
 	    }

 	    # If the config has no prompt, then we need to check if a config
 	    # that is enabled selected it. Or if we need to enable one.
 	    if (!defined($prompts{$config}) && defined($selects{$config})) {
 		$process_selects{$config} = 1;
 	    }
 	}
     }
 }

 sub loop_select {

     foreach my $config (keys %process_selects) {
 	$config =~ s/^CONFIG_//;

 	dprint "Process select $config\n";

 	# config has no prompt and must be selected.
 	parse_config_selects $config, $selects{$config};
     }
 }

 while ($repeat) {
     # Get the first set of configs and their dependencies.
     loop_depend;

     $repeat = 0;

     # Now we need to see if we have to check selects;
     loop_select;
 }

 my %setconfigs;
 my @preserved_kconfigs;
 if (defined($ENV{'LMC_KEEP'})) {
 	@preserved_kconfigs = split(/:/,$ENV{LMC_KEEP});
 }

 sub in_preserved_kconfigs {
     my $kconfig = $config2kfile{$_[0]};
     if (!defined($kconfig)) {
 	return 0;
     }
     foreach my $excl (@preserved_kconfigs) {
 	if($kconfig =~ /^$excl/) {
 	    return 1;
 	}
     }
     return 0;
 }

 # Finally, read the .config file and turn off any module enabled that
 # we could not find a reason to keep enabled.
 foreach my $line (@config_file) {
     $_ = $line;

     if (/CONFIG_IKCONFIG/) {
 	if (/# CONFIG_IKCONFIG is not set/) {
 	    # enable IKCONFIG at least as a module
 	    print "CONFIG_IKCONFIG=m\n";
 	    # don't ask about PROC
 	    print "# CONFIG_IKCONFIG_PROC is not set\n";
 	} else {
 	    print;
 	}
 	next;
     }

     if (/CONFIG_MODULE_SIG_KEY="(.+)"/) {
 	my $orig_cert = $1;
 	my $default_cert = "certs/signing_key.pem";

 	# Check that the logic in this script still matches the one in Kconfig
 	if (!defined($depends{"MODULE_SIG_KEY"}) ||
 	    $depends{"MODULE_SIG_KEY"} !~ /"\Q$default_cert\E"/) {
 	    print STDERR "WARNING: MODULE_SIG_KEY assertion failure, ",
 		"update needed to ", __FILE__, " line ", __LINE__, "\n";
 	    print;
 	} elsif ($orig_cert ne $default_cert && ! -f $orig_cert) {
 	    print STDERR "Module signature verification enabled but ",
 		"module signing key \"$orig_cert\" not found. Resetting ",
 		"signing key to default value.\n";
 	    print "CONFIG_MODULE_SIG_KEY=\"$default_cert\"\n";
 	} else {
 	    print;
 	}
 	next;
     }

     if (/CONFIG_SYSTEM_TRUSTED_KEYS="(.+)"/) {
 	my $orig_keys = $1;

 	if (! -f $orig_keys) {
 	    print STDERR "System keyring enabled but keys \"$orig_keys\" ",
 		"not found. Resetting keys to default value.\n";
 	    print "CONFIG_SYSTEM_TRUSTED_KEYS=\"\"\n";
 	} else {
 	    print;
 	}
 	next;
     }

     if (/^(CONFIG.*)=(m|y)/) {
 	if (in_preserved_kconfigs($1)) {
 	    dprint "Preserve config $1";
 	    print;
 	    next;
 	}
 	if (defined($configs{$1})) {
 	    if ($localyesconfig) {
 		$setconfigs{$1} = 'y';
 		print "$1=y\n";
 		next;
 	    } else {
 		$setconfigs{$1} = $2;
 	    }
 	} elsif ($2 eq "m") {
 	    print "# $1 is not set\n";
 	    next;
 	}
     }
     print;
 }

 # Integrity check, make sure all modules that we want enabled do
 # indeed have their configs set.
 loop:
 foreach my $module (keys(%modules)) {
     if (defined($objects{$module})) {
 	my @arr = @{$objects{$module}};
 	foreach my $conf (@arr) {
 	    if (defined($setconfigs{$conf})) {
 		next loop;
 	    }
 	}
 	print STDERR "module $module did not have configs";
 	foreach my $conf (@arr) {
 	    print STDERR " " , $conf;
 	}
 	print STDERR "\n";
     }
 }

 # vim: softtabstop=4
	#!/usr/bin/env perl
	# SPDX-License-Identifier: GPL-2.0
	#
	# Copyright 2005-2009 - Steven Rostedt
	#
	# It's simple enough to figure out how this works.
	# If not, then you can ask me at stripconfig@goodmis.org
	#
	# What it does?
	#
	# If you have installed a Linux kernel from a distribution
	# that turns on way too many modules than you need, and
	# you only want the modules you use, then this program
	# is perfect for you.
	#
	# It gives you the ability to turn off all the modules that are
	# not loaded on your system.
	#
	# Howto:
	#
	# 1. Boot up the kernel that you want to stream line the config on.
	# 2. Change directory to the directory holding the source of the
	# kernel that you just booted.
	# 3. Copy the configuration file to this directory as .config
	# 4. Have all your devices that you need modules for connected and
	# operational (make sure that their corresponding modules are loaded)
	# 5. Run this script redirecting the output to some other file
	# like config_strip.
	# 6. Back up your old config (if you want too).
	# 7. copy the config_strip file to .config
	# 8. Run "make oldconfig"
	#
	# Now your kernel is ready to be built with only the modules that
	# are loaded.
	#
	# Here's what I did with my Debian distribution.
	#
	# cd /usr/src/linux-2.6.10
	# cp /boot/config-2.6.10-1-686-smp .config
	# ~/bin/streamline_config > config_strip
	# mv .config config_sav
	# mv config_strip .config
	# make oldconfig
	#
	use warnings;
	use strict;
	use Getopt::Long;

	# set the environment variable LOCALMODCONFIG_DEBUG to get
	# debug output.
	my $debugprint = 0;
	$debugprint = 1 if (defined($ENV{LOCALMODCONFIG_DEBUG}));

	sub dprint {
	return if (!$debugprint);
	print STDERR @_;
	}

	my $uname = `uname -r`;
	chomp $uname;

	my @searchconfigs = (
	{
	"file" => ".config",
	"exec" => "cat",
	},
	{
	"file" => "/proc/config.gz",
	"exec" => "zcat",
	},
	{
	"file" => "/boot/config-$uname",
	"exec" => "cat",
	},
	{
	"file" => "/boot/vmlinuz-$uname",
	"exec" => "scripts/extract-ikconfig",
	"test" => "scripts/extract-ikconfig",
	},
	{
	"file" => "vmlinux",
	"exec" => "scripts/extract-ikconfig",
	"test" => "scripts/extract-ikconfig",
	},
	{
	"file" => "/lib/modules/$uname/kernel/kernel/configs.ko",
	"exec" => "scripts/extract-ikconfig",
	"test" => "scripts/extract-ikconfig",
	},
	{
	"file" => "kernel/configs.ko",
	"exec" => "scripts/extract-ikconfig",
	"test" => "scripts/extract-ikconfig",
	},
	{
	"file" => "kernel/configs.o",
	"exec" => "scripts/extract-ikconfig",
	"test" => "scripts/extract-ikconfig",
	},
	);

	sub read_config {
	foreach my $conf (@searchconfigs) {
	my $file = $conf->{"file"};

	next if ( ! -f "$file");

	if (defined($conf->{"test"})) {
	`$conf->{"test"} $conf->{"file"} 2>/dev/null`;
	next if ($?);
	}

	my $exec = $conf->{"exec"};

	print STDERR "using config: '$file'\n";

	open(my $infile, '-\|', "$exec $file") \|\| die "Failed to run $exec $file";
	my @x = <$infile>;
	close $infile;
	return @x;
	}
	die "No config file found";
	}

	my @config_file = read_config;

	# Parse options
	my $localmodconfig = 0;
	my $localyesconfig = 0;

	GetOptions("localmodconfig" => \$localmodconfig,
	"localyesconfig" => \$localyesconfig);

	# Get the build source and top level Kconfig file (passed in)
	my $ksource = ($ARGV[0] ? $ARGV[0] : '.');
	my $kconfig = $ARGV[1];
	my $lsmod_file = $ENV{'LSMOD'};

	my @makefiles = `find $ksource -name Makefile -or -name Kbuild 2>/dev/null`;
	chomp @makefiles;

	my %depends;
	my %selects;
	my %prompts;
	my %objects;
	my %config2kfile;
	my $var;
	my $iflevel = 0;
	my @ifdeps;

	# prevent recursion
	my %read_kconfigs;

	sub read_kconfig {
	my ($kconfig) = @_;

	my $state = "NONE";
	my $config;

	my $cont = 0;
	my $line;

	my $source = "$ksource/$kconfig";
	my $last_source = "";

	# Check for any environment variables used
	while ($source =~ /\$\((\w+)\)/ && $last_source ne $source) {
	my $env = $1;
	$last_source = $source;
	$source =~ s/\$\($env\)/$ENV{$env}/;
	}

	open(my $kinfile, '<', $source) \|\| die "Can't open $kconfig";
	while (<$kinfile>) {
	chomp;

	# Make sure that lines ending with \ continue
	if ($cont) {
	$_ = $line . " " . $_;
	}

	if (s/\\$//) {
	$cont = 1;
	$line = $_;
	next;
	}

	$cont = 0;

	# collect any Kconfig sources
	if (/^source\s+"?([^"]+)/) {
	my $kconfig = $1;
	# prevent reading twice.
	if (!defined($read_kconfigs{$kconfig})) {
	$read_kconfigs{$kconfig} = 1;
	read_kconfig($kconfig);
	}
	next;
	}

	# configs found
	if (/^\s(menu)?config\s+(\S+)\s$/) {
	$state = "NEW";
	$config = $2;
	$config2kfile{"CONFIG_$config"} = $kconfig;

	# Add depends for 'if' nesting
	for (my $i = 0; $i < $iflevel; $i++) {
	if ($i) {
	$depends{$config} .= " " . $ifdeps[$i];
	} else {
	$depends{$config} = $ifdeps[$i];
	}
	$state = "DEP";
	}

	# collect the depends for the config
	} elsif ($state eq "NEW" && /^\sdepends\s+on\s+(.)$/) {
	$state = "DEP";
	$depends{$config} = $1;
	} elsif ($state eq "DEP" && /^\sdepends\s+on\s+(.)$/) {
	$depends{$config} .= " " . $1;
	} elsif ($state eq "DEP" && /^\sdef(_(bool\|tristate)\|ault)\s+(\S.)$/) {
	my $dep = $3;
	if ($dep !~ /^\s(y\|m\|n)\s$/) {
	$dep =~ s/.*\sif\s+//;
	$depends{$config} .= " " . $dep;
	dprint "Added default depends $dep to $config\n";
	}

	# Get the configs that select this config
	} elsif ($state ne "NONE" && /^\s*select\s+(\S+)/) {
	my $conf = $1;
	if (defined($selects{$conf})) {
	$selects{$conf} .= " " . $config;
	} else {
	$selects{$conf} = $config;
	}

	# configs without prompts must be selected
	} elsif ($state ne "NONE" && /^\s*(tristate\s+\S\|prompt\b)/) {
	# note if the config has a prompt
	$prompts{$config} = 1;

	# Check for if statements
	} elsif (/^if\s+(.\S)\s$/) {
	my $deps = $1;
	# remove beginning and ending non text
	$deps =~ s/^[^a-zA-Z0-9_]*//;
	$deps =~ s/[^a-zA-Z0-9_]*$//;

	my @deps = split /[^a-zA-Z0-9_]+/, $deps;

	$ifdeps[$iflevel++] = join ':', @deps;

	} elsif (/^endif/) {

	$iflevel-- if ($iflevel);

	# stop on "help" and keywords that end a menu entry
	} elsif (/^\s(---)?help(---)?\s$/ \|\| /^(comment\|choice\|menu)\b/) {
	$state = "NONE";
	}
	}
	close($kinfile);
	}

	if ($kconfig) {
	read_kconfig($kconfig);
	}

	# Makefiles can use variables to define their dependencies
	sub convert_vars {
	my ($line, %vars) = @_;

	my $process = "";

	while ($line =~ s/^(.?)(\$\((.?)\))//) {
	my $start = $1;
	my $variable = $2;
	my $var = $3;

	if (defined($vars{$var})) {
	$process .= $start . $vars{$var};
	} else {
	$process .= $start . $variable;
	}
	}

	$process .= $line;

	return $process;
	}

	# Read all Makefiles to map the configs to the objects
	foreach my $makefile (@makefiles) {

	my $line = "";
	my %make_vars;

	open(my $infile, '<', $makefile) \|\| die "Can't open $makefile";
	while (<$infile>) {
	# if this line ends with a backslash, continue
	chomp;
	if (/^(.*)\\$/) {
	$line .= $1;
	next;
	}

	$line .= $_;
	$_ = $line;
	$line = "";

	my $objs;

	# Convert variables in a line (could define configs)
	$_ = convert_vars($_, %make_vars);

	# collect objects after obj-$(CONFIG_FOO_BAR)
	if (/obj-\$\((CONFIG_[^\)])\)\s[+:]?=\s(.)/) {
	$var = $1;
	$objs = $2;

	# check if variables are set
	} elsif (/^\s(\S+)\s[:]?=\s(.\S)/) {
	$make_vars{$1} = $2;
	}
	if (defined($objs)) {
	foreach my $obj (split /\s+/,$objs) {
	$obj =~ s/-/_/g;
	if ($obj =~ /(.*)\.o$/) {
	# Objects may be enabled by more than one config.
	# Store configs in an array.
	my @arr;

	if (defined($objects{$1})) {
	@arr = @{$objects{$1}};
	}

	$arr[$#arr+1] = $var;

	# The objects have a hash mapping to a reference
	# of an array of configs.
	$objects{$1} = \@arr;
	}
	}
	}
	}
	close($infile);
	}

	my %modules;
	my $linfile;

	if (defined($lsmod_file)) {
	if ( ! -f $lsmod_file) {
	if ( -f $ENV{'objtree'}."/".$lsmod_file) {
	$lsmod_file = $ENV{'objtree'}."/".$lsmod_file;
	} else {
	die "$lsmod_file not found";
	}
	}

	my $otype = ( -x $lsmod_file) ? '-\|' : '<';
	open($linfile, $otype, $lsmod_file);

	} else {

	# see what modules are loaded on this system
	my $lsmod;

	foreach my $dir ( ("/sbin", "/bin", "/usr/sbin", "/usr/bin") ) {
	if ( -x "$dir/lsmod" ) {
	$lsmod = "$dir/lsmod";
	last;
	}
	}
	if (!defined($lsmod)) {
	# try just the path
	$lsmod = "lsmod";
	}

	open($linfile, '-\|', $lsmod) \|\| die "Can not call lsmod with $lsmod";
	}

	while (<$linfile>) {
	next if (/^Module/); # Skip the first line.
	if (/^(\S+)/) {
	$modules{$1} = 1;
	}
	}
	close ($linfile);

	# add to the configs hash all configs that are needed to enable
	# a loaded module. This is a direct obj-${CONFIG_FOO} += bar.o
	# where we know we need bar.o so we add FOO to the list.
	my %configs;
	foreach my $module (keys(%modules)) {
	if (defined($objects{$module})) {
	my @arr = @{$objects{$module}};
	foreach my $conf (@arr) {
	$configs{$conf} = $module;
	dprint "$conf added by direct ($module)\n";
	if ($debugprint) {
	my $c=$conf;
	$c =~ s/^CONFIG_//;
	if (defined($depends{$c})) {
	dprint " deps = $depends{$c}\n";
	} else {
	dprint " no deps\n";
	}
	}
	}
	} else {
	# Most likely, someone has a custom (binary?) module loaded.
	print STDERR "$module config not found!!\n";
	}
	}

	# Read the current config, and see what is enabled. We want to
	# ignore configs that we would not enable anyway.

	my %orig_configs;
	my $valid = "A-Za-z_0-9";

	foreach my $line (@config_file) {
	$_ = $line;

	if (/(CONFIG_[$valid]*)=(m\|y)/) {
	$orig_configs{$1} = $2;
	}
	}

	my $repeat = 1;

	my $depconfig;

	#
	# Note, we do not care about operands (like: &&, \|\|, !) we want to add any
	# config that is in the depend list of another config. This script does
	# not enable configs that are not already enabled. If we come across a
	# config A that depends on !B, we can still add B to the list of depends
	# to keep on. If A was on in the original config, B would not have been
	# and B would not be turned on by this script.
	#
	sub parse_config_depends
	{
	my ($p) = @_;

	while ($p =~ /[$valid]/) {

	if ($p =~ /^[^$valid]*([$valid]+)/) {
	my $conf = "CONFIG_" . $1;

	$p =~ s/^[^$valid]*[$valid]+//;

	# We only need to process if the depend config is a module
	if (!defined($orig_configs{$conf}) \|\| $orig_configs{$conf} eq "y") {
	next;
	}

	if (!defined($configs{$conf})) {
	# We must make sure that this config has its
	# dependencies met.
	$repeat = 1; # do again
	dprint "$conf selected by depend $depconfig\n";
	$configs{$conf} = 1;
	}
	} else {
	die "this should never happen";
	}
	}
	}

	# Select is treated a bit differently than depends. We call this
	# when a config has no prompt and requires another config to be
	# selected. We use to just select all configs that selected this
	# config, but found that that can balloon into enabling hundreds
	# of configs that we do not care about.
	#
	# The idea is we look at all the configs that select it. If one
	# is already in our list of configs to enable, then there's nothing
	# else to do. If there isn't, we pick the first config that was
	# enabled in the original config and use that.
	sub parse_config_selects
	{
	my ($config, $p) = @_;

	my $next_config;

	while ($p =~ /[$valid]/) {

	if ($p =~ /^[^$valid]*([$valid]+)/) {
	my $conf = "CONFIG_" . $1;

	$p =~ s/^[^$valid]*[$valid]+//;

	# Make sure that this config exists in the current .config file
	if (!defined($orig_configs{$conf})) {
	dprint "$conf not set for $config select\n";
	next;
	}

	# Check if something other than a module selects this config
	if (defined($orig_configs{$conf}) && $orig_configs{$conf} ne "m") {
	dprint "$conf (non module) selects config, we are good\n";
	# we are good with this
	return;
	}
	if (defined($configs{$conf})) {
	dprint "$conf selects $config so we are good\n";
	# A set config selects this config, we are good
	return;
	}
	# Set this config to be selected
	if (!defined($next_config)) {
	$next_config = $conf;
	}
	} else {
	die "this should never happen";
	}
	}

	# If no possible config selected this, then something happened.
	if (!defined($next_config)) {
	print STDERR "WARNING: $config is required, but nothing in the\n";
	print STDERR " current config selects it.\n";
	return;
	}

	# If we are here, then we found no config that is set and
	# selects this config. Repeat.
	$repeat = 1;
	# Make this config need to be selected
	$configs{$next_config} = 1;
	dprint "$next_config selected by select $config\n";
	}

	my %process_selects;

	# loop through all configs, select their dependencies.
	sub loop_depend {
	$repeat = 1;

	while ($repeat) {
	$repeat = 0;

	forloop:
	foreach my $config (keys %configs) {

	# If this config is not a module, we do not need to process it
	if (defined($orig_configs{$config}) && $orig_configs{$config} ne "m") {
	next forloop;
	}

	$config =~ s/^CONFIG_//;
	$depconfig = $config;

	if (defined($depends{$config})) {
	# This config has dependencies. Make sure they are also included
	parse_config_depends $depends{$config};
	}

	# If the config has no prompt, then we need to check if a config
	# that is enabled selected it. Or if we need to enable one.
	if (!defined($prompts{$config}) && defined($selects{$config})) {
	$process_selects{$config} = 1;
	}
	}
	}
	}

	sub loop_select {

	foreach my $config (keys %process_selects) {
	$config =~ s/^CONFIG_//;

	dprint "Process select $config\n";

	# config has no prompt and must be selected.
	parse_config_selects $config, $selects{$config};
	}
	}

	while ($repeat) {
	# Get the first set of configs and their dependencies.
	loop_depend;

	$repeat = 0;

	# Now we need to see if we have to check selects;
	loop_select;
	}

	my %setconfigs;
	my @preserved_kconfigs;
	if (defined($ENV{'LMC_KEEP'})) {
	@preserved_kconfigs = split(/:/,$ENV{LMC_KEEP});
	}

	sub in_preserved_kconfigs {
	my $kconfig = $config2kfile{$_[0]};
	if (!defined($kconfig)) {
	return 0;
	}
	foreach my $excl (@preserved_kconfigs) {
	if($kconfig =~ /^$excl/) {
	return 1;
	}
	}
	return 0;
	}

	# Finally, read the .config file and turn off any module enabled that
	# we could not find a reason to keep enabled.
	foreach my $line (@config_file) {
	$_ = $line;

	if (/CONFIG_IKCONFIG/) {
	if (/# CONFIG_IKCONFIG is not set/) {
	# enable IKCONFIG at least as a module
	print "CONFIG_IKCONFIG=m\n";
	# don't ask about PROC
	print "# CONFIG_IKCONFIG_PROC is not set\n";
	} else {
	print;
	}
	next;
	}

	if (/CONFIG_MODULE_SIG_KEY="(.+)"/) {
	my $orig_cert = $1;
	my $default_cert = "certs/signing_key.pem";

	# Check that the logic in this script still matches the one in Kconfig
	if (!defined($depends{"MODULE_SIG_KEY"}) \|\|
	$depends{"MODULE_SIG_KEY"} !~ /"\Q$default_cert\E"/) {
	print STDERR "WARNING: MODULE_SIG_KEY assertion failure, ",
	"update needed to ", __FILE__, " line ", __LINE__, "\n";
	print;
	} elsif ($orig_cert ne $default_cert && ! -f $orig_cert) {
	print STDERR "Module signature verification enabled but ",
	"module signing key \"$orig_cert\" not found. Resetting ",
	"signing key to default value.\n";
	print "CONFIG_MODULE_SIG_KEY=\"$default_cert\"\n";
	} else {
	print;
	}
	next;
	}

	if (/CONFIG_SYSTEM_TRUSTED_KEYS="(.+)"/) {
	my $orig_keys = $1;

	if (! -f $orig_keys) {
	print STDERR "System keyring enabled but keys \"$orig_keys\" ",
	"not found. Resetting keys to default value.\n";
	print "CONFIG_SYSTEM_TRUSTED_KEYS=\"\"\n";
	} else {
	print;
	}
	next;
	}

	if (/^(CONFIG.*)=(m\|y)/) {
	if (in_preserved_kconfigs($1)) {
	dprint "Preserve config $1";
	print;
	next;
	}
	if (defined($configs{$1})) {
	if ($localyesconfig) {
	$setconfigs{$1} = 'y';
	print "$1=y\n";
	next;
	} else {
	$setconfigs{$1} = $2;
	}
	} elsif ($2 eq "m") {
	print "# $1 is not set\n";
	next;
	}
	}
	print;
	}

	# Integrity check, make sure all modules that we want enabled do
	# indeed have their configs set.
	loop:
	foreach my $module (keys(%modules)) {
	if (defined($objects{$module})) {
	my @arr = @{$objects{$module}};
	foreach my $conf (@arr) {
	if (defined($setconfigs{$conf})) {
	next loop;
	}
	}
	print STDERR "module $module did not have configs";
	foreach my $conf (@arr) {
	print STDERR " " , $conf;
	}
	print STDERR "\n";
	}
	}

	# vim: softtabstop=4