#!/usr/bin/perl -w
#
# Copywrite 2005-2009 - Steven Rostedt
# Licensed under the terms of the GNU GPL License version 2
#
# 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 configuraton 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
#
my $config = ".config";
my $linuxpath = ".";
my $uname = `uname -r`;
chomp $uname;
my @searchconfigs = (
{
"file" => "/proc/config.gz",
"exec" => "zcat",
},
{
"file" => "/boot/vmlinuz-$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",
},
{
"file" => ".config",
"exec" => "cat",
},
);
sub find_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(CIN, "$exec $file |") || die "Failed to run $exec $file";
return;
}
die "No config file found";
}
find_config;
my @makefiles = `find $linuxpath -name Makefile`;
my %depends;
my %selects;
my %prompts;
my %objects;
my $var;
my $cont = 0;
# Get the top level Kconfig file (passed in)
my $kconfig = $ARGV[0];
# prevent recursion
my %read_kconfigs;
sub read_kconfig {
my ($kconfig) = @_;
my $state = "NONE";
my $config;
my @kconfigs;
open(KIN, $kconfig) || die "Can't open $kconfig";
while (<KIN>) {
chomp;
# collect any Kconfig sources
if (/^source\s*"(.*)"/) {
$kconfigs[$#kconfigs+1] = $1;
}
# configs found
if (/^\s*config\s+(\S+)\s*$/) {
$state = "NEW";
$config = $1;
# collect the depends for the config
} elsif ($state eq "NEW" && /^\s*depends\s+on\s+(.*)$/) {
$state = "DEP";
$depends{$config} = $1;
} elsif ($state eq "DEP" && /^\s*depends\s+on\s+(.*)$/) {
$depends{$config} .= " " . $1;
# Get the configs that select this config
} elsif ($state ne "NONE" && /^\s*select\s+(\S+)/) {
if (defined($selects{$1})) {
$selects{$1} .= " " . $config;
} else {
$selects{$1} = $config;
}
# configs without prompts must be selected
} elsif ($state ne "NONE" && /^\s*tristate\s\S/) {
# note if the config has a prompt
$prompt{$config} = 1;
# stop on "help"
} elsif (/^\s*help\s*$/) {
$state = "NONE";
}
}
close(KIN);
# read in any configs that were found.
foreach $kconfig (@kconfigs) {
if (!defined($read_kconfigs{$kconfig})) {
$read_kconfigs{$kconfig} = 1;
read_kconfig($kconfig);
}
}
}
if ($kconfig) {
read_kconfig($kconfig);
}
# Read all Makefiles to map the configs to the objects
foreach my $makefile (@makefiles) {
chomp $makefile;
open(MIN,$makefile) || die "Can't open $makefile";
while (<MIN>) {
my $objs;
# is this a line after a line with a backslash?
if ($cont && /(\S.*)$/) {
$objs = $1;
}
$cont = 0;
# collect objects after obj-$(CONFIG_FOO_BAR)
if (/obj-\$\((CONFIG_[^\)]*)\)\s*[+:]?=\s*(.*)/) {
$var = $1;
$objs = $2;
}
if (defined($objs)) {
# test if the line ends with a backslash
if ($objs =~ m,(.*)\\$,) {
$objs = $1;
$cont = 1;
}
foreach my $obj (split /\s+/,$objs) {
$obj =~ s/-/_/g;
if ($obj =~ /(.*)\.o$/) {
# Objects may bes enabled by more than one config.
# Store configs in an array.
my @arr;
if (defined($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(MIN);
}
my %modules;
# see what modules are loaded on this system
open(LIN,"/sbin/lsmod|") || die "Cant lsmod";
while (<LIN>) {
next if (/^Module/); # Skip the first line.
if (/^(\S+)/) {
$modules{$1} = 1;
}
}
close (LIN);
# add to the configs hash all configs that are needed to enable
# a loaded module.
my %configs;
foreach my $module (keys(%modules)) {
if (defined($objects{$module})) {
@arr = @{$objects{$module}};
foreach my $conf (@arr) {
$configs{$conf} = $module;
}
} else {
# Most likely, someone has a custom (binary?) module loaded.
print STDERR "$module config not found!!\n";
}
}
my $valid = "A-Za-z_0-9";
my $repeat = 1;
#
# Note, we do not care about operands (like: &&, ||, !) we want to add any
# config that is in the depend list of another config. This script does
# not enable configs that are not already enabled. If we come across a
# config A that depends on !B, we can still add B to the list of depends
# to keep on. If A was on in the original config, B would not have been
# and B would not be turned on by this script.
#
sub parse_config_dep_select
{
my ($p) = @_;
while ($p =~ /[$valid]/) {
if ($p =~ /^[^$valid]*([$valid]+)/) {
my $conf = "CONFIG_" . $1;
$p =~ s/^[^$valid]*[$valid]+//;
if (!defined($configs{$conf})) {
# We must make sure that this config has its
# dependencies met.
$repeat = 1; # do again
$configs{$conf} = 1;
}
} else {
die "this should never happen";
}
}
}
while ($repeat) {
$repeat = 0;
foreach my $config (keys %configs) {
$config =~ s/^CONFIG_//;
if (defined($depends{$config})) {
# This config has dependencies. Make sure they are also included
parse_config_dep_select $depends{$config};
}
if (defined($prompt{$config}) || !defined($selects{$config})) {
next;
}
# config has no prompt and must be selected.
parse_config_dep_select $selects{$config};
}
}
my %setconfigs;
# Finally, read the .config file and turn off any module enabled that
# we could not find a reason to keep enabled.
while(<CIN>) {
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.*)=(m|y)/) {
if (defined($configs{$1})) {
$setconfigs{$1} = $2;
} elsif ($2 eq "m") {
print "# $1 is not set\n";
next;
}
}
print;
}
close(CIN);
# 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";
}
}
