2 # SPDX-License-Identifier: GPL-2.0
4 # Copyright 2005-2009 - Steven Rostedt
6 # It's simple enough to figure out how this works.
7 # If not, then you can ask me at stripconfig@goodmis.org
11 # If you have installed a Linux kernel from a distribution
12 # that turns on way too many modules than you need, and
13 # you only want the modules you use, then this program
16 # It gives you the ability to turn off all the modules that are
17 # not loaded on your system.
21 # 1. Boot up the kernel that you want to stream line the config on.
22 # 2. Change directory to the directory holding the source of the
23 # kernel that you just booted.
24 # 3. Copy the configuraton file to this directory as .config
25 # 4. Have all your devices that you need modules for connected and
26 # operational (make sure that their corresponding modules are loaded)
27 # 5. Run this script redirecting the output to some other file
29 # 6. Back up your old config (if you want too).
30 # 7. copy the config_strip file to .config
31 # 8. Run "make oldconfig"
33 # Now your kernel is ready to be built with only the modules that
36 # Here's what I did with my Debian distribution.
38 # cd /usr/src/linux-2.6.10
39 # cp /boot/config-2.6.10-1-686-smp .config
40 # ~/bin/streamline_config > config_strip
41 # mv .config config_sav
42 # mv config_strip .config
49 # set the environment variable LOCALMODCONFIG_DEBUG to get
52 $debugprint = 1 if (defined($ENV{LOCALMODCONFIG_DEBUG
}));
55 return if (!$debugprint);
59 my $uname = `uname -r`;
68 "file" => "/proc/config.gz",
72 "file" => "/boot/config-$uname",
76 "file" => "/boot/vmlinuz-$uname",
77 "exec" => "scripts/extract-ikconfig",
78 "test" => "scripts/extract-ikconfig",
82 "exec" => "scripts/extract-ikconfig",
83 "test" => "scripts/extract-ikconfig",
86 "file" => "/lib/modules/$uname/kernel/kernel/configs.ko",
87 "exec" => "scripts/extract-ikconfig",
88 "test" => "scripts/extract-ikconfig",
91 "file" => "kernel/configs.ko",
92 "exec" => "scripts/extract-ikconfig",
93 "test" => "scripts/extract-ikconfig",
96 "file" => "kernel/configs.o",
97 "exec" => "scripts/extract-ikconfig",
98 "test" => "scripts/extract-ikconfig",
103 foreach my $conf (@searchconfigs) {
104 my $file = $conf->{"file"};
106 next if ( ! -f
"$file");
108 if (defined($conf->{"test"})) {
109 `$conf->{"test"} $conf->{"file"} 2>/dev/null`;
113 my $exec = $conf->{"exec"};
115 print STDERR
"using config: '$file'\n";
117 open(my $infile, '-|', "$exec $file") || die "Failed to run $exec $file";
122 die "No config file found";
125 my @config_file = read_config
;
128 my $localmodconfig = 0;
129 my $localyesconfig = 0;
131 GetOptions
("localmodconfig" => \
$localmodconfig,
132 "localyesconfig" => \
$localyesconfig);
134 # Get the build source and top level Kconfig file (passed in)
135 my $ksource = ($ARGV[0] ?
$ARGV[0] : '.');
136 my $kconfig = $ARGV[1];
137 my $lsmod_file = $ENV{'LSMOD'};
139 my @makefiles = `find $ksource -name Makefile -or -name Kbuild 2>/dev/null`;
162 my $source = "$ksource/$kconfig";
163 my $last_source = "";
165 # Check for any environment variables used
166 while ($source =~ /\$\((\w+)\)/ && $last_source ne $source) {
168 $last_source = $source;
169 $source =~ s/\$\($env\)/$ENV{$env}/;
172 open(my $kinfile, '<', $source) || die "Can't open $kconfig";
176 # Make sure that lines ending with \ continue
178 $_ = $line . " " . $_;
189 # collect any Kconfig sources
190 if (/^source\s+"?([^"]+)/) {
192 # prevent reading twice.
193 if (!defined($read_kconfigs{$kconfig})) {
194 $read_kconfigs{$kconfig} = 1;
195 read_kconfig
($kconfig);
201 if (/^\s*(menu)?config\s+(\S+)\s*$/) {
205 # Add depends for 'if' nesting
206 for (my $i = 0; $i < $iflevel; $i++) {
208 $depends{$config} .= " " . $ifdeps[$i];
210 $depends{$config} = $ifdeps[$i];
215 # collect the depends for the config
216 } elsif ($state eq "NEW" && /^\s*depends\s+on\s+(.*)$/) {
218 $depends{$config} = $1;
219 } elsif ($state eq "DEP" && /^\s*depends\s+on\s+(.*)$/) {
220 $depends{$config} .= " " . $1;
221 } elsif ($state eq "DEP" && /^\s*def(_(bool|tristate)|ault)\s+(\S.*)$/) {
223 if ($dep !~ /^\s*(y|m|n)\s*$/) {
224 $dep =~ s/.*\sif\s+//;
225 $depends{$config} .= " " . $dep;
226 dprint
"Added default depends $dep to $config\n";
229 # Get the configs that select this config
230 } elsif ($state ne "NONE" && /^\s*select\s+(\S+)/) {
232 if (defined($selects{$conf})) {
233 $selects{$conf} .= " " . $config;
235 $selects{$conf} = $config;
238 # configs without prompts must be selected
239 } elsif ($state ne "NONE" && /^\s*(tristate\s+\S|prompt\b)/) {
240 # note if the config has a prompt
241 $prompts{$config} = 1;
243 # Check for if statements
244 } elsif (/^if\s+(.*\S)\s*$/) {
246 # remove beginning and ending non text
247 $deps =~ s/^[^a-zA-Z0-9_]*//;
248 $deps =~ s/[^a-zA-Z0-9_]*$//;
250 my @deps = split /[^a-zA-Z0-9_]+/, $deps;
252 $ifdeps[$iflevel++] = join ':', @deps;
256 $iflevel-- if ($iflevel);
258 # stop on "help" and keywords that end a menu entry
259 } elsif (/^\s*(---)?help(---)?\s*$/ || /^(comment|choice|menu)\b/) {
267 read_kconfig
($kconfig);
270 # Makefiles can use variables to define their dependencies
272 my ($line, %vars) = @_;
276 while ($line =~ s/^(.*?)(\$\((.*?)\))//) {
281 if (defined($vars{$var})) {
282 $process .= $start . $vars{$var};
284 $process .= $start . $variable;
293 # Read all Makefiles to map the configs to the objects
294 foreach my $makefile (@makefiles) {
299 open(my $infile, '<', $makefile) || die "Can't open $makefile";
301 # if this line ends with a backslash, continue
314 # Convert variables in a line (could define configs)
315 $_ = convert_vars
($_, %make_vars);
317 # collect objects after obj-$(CONFIG_FOO_BAR)
318 if (/obj-\$\((CONFIG_[^\)]*)\)\s*[+:]?=\s*(.*)/) {
322 # check if variables are set
323 } elsif (/^\s*(\S+)\s*[:]?=\s*(.*\S)/) {
326 if (defined($objs)) {
327 foreach my $obj (split /\s+/,$objs) {
329 if ($obj =~ /(.*)\.o$/) {
330 # Objects may be enabled by more than one config.
331 # Store configs in an array.
334 if (defined($objects{$1})) {
335 @arr = @
{$objects{$1}};
338 $arr[$#arr+1] = $var;
340 # The objects have a hash mapping to a reference
341 # of an array of configs.
342 $objects{$1} = \
@arr;
353 if (defined($lsmod_file)) {
354 if ( ! -f
$lsmod_file) {
355 if ( -f
$ENV{'objtree'}."/".$lsmod_file) {
356 $lsmod_file = $ENV{'objtree'}."/".$lsmod_file;
358 die "$lsmod_file not found";
362 my $otype = ( -x
$lsmod_file) ?
'-|' : '<';
363 open($linfile, $otype, $lsmod_file);
367 # see what modules are loaded on this system
370 foreach my $dir ( ("/sbin", "/bin", "/usr/sbin", "/usr/bin") ) {
371 if ( -x
"$dir/lsmod" ) {
372 $lsmod = "$dir/lsmod";
376 if (!defined($lsmod)) {
381 open($linfile, '-|', $lsmod) || die "Can not call lsmod with $lsmod";
385 next if (/^Module/); # Skip the first line.
392 # add to the configs hash all configs that are needed to enable
393 # a loaded module. This is a direct obj-${CONFIG_FOO} += bar.o
394 # where we know we need bar.o so we add FOO to the list.
396 foreach my $module (keys(%modules)) {
397 if (defined($objects{$module})) {
398 my @arr = @
{$objects{$module}};
399 foreach my $conf (@arr) {
400 $configs{$conf} = $module;
401 dprint
"$conf added by direct ($module)\n";
405 if (defined($depends{$c})) {
406 dprint
" deps = $depends{$c}\n";
413 # Most likely, someone has a custom (binary?) module loaded.
414 print STDERR
"$module config not found!!\n";
418 # Read the current config, and see what is enabled. We want to
419 # ignore configs that we would not enable anyway.
422 my $valid = "A-Za-z_0-9";
424 foreach my $line (@config_file) {
427 if (/(CONFIG_[$valid]*)=(m|y)/) {
428 $orig_configs{$1} = $2;
437 # Note, we do not care about operands (like: &&, ||, !) we want to add any
438 # config that is in the depend list of another config. This script does
439 # not enable configs that are not already enabled. If we come across a
440 # config A that depends on !B, we can still add B to the list of depends
441 # to keep on. If A was on in the original config, B would not have been
442 # and B would not be turned on by this script.
444 sub parse_config_depends
448 while ($p =~ /[$valid]/) {
450 if ($p =~ /^[^$valid]*([$valid]+)/) {
451 my $conf = "CONFIG_" . $1;
453 $p =~ s/^[^$valid]*[$valid]+//;
455 # We only need to process if the depend config is a module
456 if (!defined($orig_configs{$conf}) || $orig_configs{$conf} eq "y") {
460 if (!defined($configs{$conf})) {
461 # We must make sure that this config has its
463 $repeat = 1; # do again
464 dprint
"$conf selected by depend $depconfig\n";
468 die "this should never happen";
473 # Select is treated a bit differently than depends. We call this
474 # when a config has no prompt and requires another config to be
475 # selected. We use to just select all configs that selected this
476 # config, but found that that can balloon into enabling hundreds
477 # of configs that we do not care about.
479 # The idea is we look at all the configs that select it. If one
480 # is already in our list of configs to enable, then there's nothing
481 # else to do. If there isn't, we pick the first config that was
482 # enabled in the orignal config and use that.
483 sub parse_config_selects
485 my ($config, $p) = @_;
489 while ($p =~ /[$valid]/) {
491 if ($p =~ /^[^$valid]*([$valid]+)/) {
492 my $conf = "CONFIG_" . $1;
494 $p =~ s/^[^$valid]*[$valid]+//;
496 # Make sure that this config exists in the current .config file
497 if (!defined($orig_configs{$conf})) {
498 dprint
"$conf not set for $config select\n";
502 # Check if something other than a module selects this config
503 if (defined($orig_configs{$conf}) && $orig_configs{$conf} ne "m") {
504 dprint
"$conf (non module) selects config, we are good\n";
505 # we are good with this
508 if (defined($configs{$conf})) {
509 dprint
"$conf selects $config so we are good\n";
510 # A set config selects this config, we are good
513 # Set this config to be selected
514 if (!defined($next_config)) {
515 $next_config = $conf;
518 die "this should never happen";
522 # If no possible config selected this, then something happened.
523 if (!defined($next_config)) {
524 print STDERR
"WARNING: $config is required, but nothing in the\n";
525 print STDERR
" current config selects it.\n";
529 # If we are here, then we found no config that is set and
530 # selects this config. Repeat.
532 # Make this config need to be selected
533 $configs{$next_config} = 1;
534 dprint
"$next_config selected by select $config\n";
539 # loop through all configs, select their dependencies.
547 foreach my $config (keys %configs) {
549 # If this config is not a module, we do not need to process it
550 if (defined($orig_configs{$config}) && $orig_configs{$config} ne "m") {
554 $config =~ s/^CONFIG_//;
555 $depconfig = $config;
557 if (defined($depends{$config})) {
558 # This config has dependencies. Make sure they are also included
559 parse_config_depends
$depends{$config};
562 # If the config has no prompt, then we need to check if a config
563 # that is enabled selected it. Or if we need to enable one.
564 if (!defined($prompts{$config}) && defined($selects{$config})) {
565 $process_selects{$config} = 1;
573 foreach my $config (keys %process_selects) {
574 $config =~ s/^CONFIG_//;
576 dprint
"Process select $config\n";
578 # config has no prompt and must be selected.
579 parse_config_selects
$config, $selects{$config};
584 # Get the first set of configs and their dependencies.
589 # Now we need to see if we have to check selects;
595 # Finally, read the .config file and turn off any module enabled that
596 # we could not find a reason to keep enabled.
597 foreach my $line (@config_file) {
600 if (/CONFIG_IKCONFIG/) {
601 if (/# CONFIG_IKCONFIG is not set/) {
602 # enable IKCONFIG at least as a module
603 print "CONFIG_IKCONFIG=m\n";
604 # don't ask about PROC
605 print "# CONFIG_IKCONFIG_PROC is not set\n";
612 if (/CONFIG_MODULE_SIG_KEY="(.+)"/) {
614 my $default_cert = "certs/signing_key.pem";
616 # Check that the logic in this script still matches the one in Kconfig
617 if (!defined($depends{"MODULE_SIG_KEY"}) ||
618 $depends{"MODULE_SIG_KEY"} !~ /"\Q$default_cert\E"/) {
619 print STDERR
"WARNING: MODULE_SIG_KEY assertion failure, ",
620 "update needed to ", __FILE__
, " line ", __LINE__
, "\n";
622 } elsif ($orig_cert ne $default_cert && ! -f
$orig_cert) {
623 print STDERR
"Module signature verification enabled but ",
624 "module signing key \"$orig_cert\" not found. Resetting ",
625 "signing key to default value.\n";
626 print "CONFIG_MODULE_SIG_KEY=\"$default_cert\"\n";
633 if (/CONFIG_SYSTEM_TRUSTED_KEYS="(.+)"/) {
636 if (! -f
$orig_keys) {
637 print STDERR
"System keyring enabled but keys \"$orig_keys\" ",
638 "not found. Resetting keys to default value.\n";
639 print "CONFIG_SYSTEM_TRUSTED_KEYS=\"\"\n";
646 if (/^(CONFIG.*)=(m|y)/) {
647 if (defined($configs{$1})) {
648 if ($localyesconfig) {
649 $setconfigs{$1} = 'y';
653 $setconfigs{$1} = $2;
655 } elsif ($2 eq "m") {
656 print "# $1 is not set\n";
663 # Integrity check, make sure all modules that we want enabled do
664 # indeed have their configs set.
666 foreach my $module (keys(%modules)) {
667 if (defined($objects{$module})) {
668 my @arr = @
{$objects{$module}};
669 foreach my $conf (@arr) {
670 if (defined($setconfigs{$conf})) {
674 print STDERR
"module $module did not have configs";
675 foreach my $conf (@arr) {
676 print STDERR
" " , $conf;