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#!/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 [email protected]
#
# 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
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