1#!/usr/bin/env perl 2# SPDX-License-Identifier: GPL-2.0 3# 4# Copyright 2005-2009 - Steven Rostedt 5# 6# It's simple enough to figure out how this works. 7# If not, then you can ask me at stripconfig@goodmis.org 8# 9# What it does? 10# 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 14# is perfect for you. 15# 16# It gives you the ability to turn off all the modules that are 17# not loaded on your system. 18# 19# Howto: 20# 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 configuration 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 28# like config_strip. 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" 32# 33# Now your kernel is ready to be built with only the modules that 34# are loaded. 35# 36# Here's what I did with my Debian distribution. 37# 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 43# make oldconfig 44# 45use warnings; 46use strict; 47use Getopt::Long; 48 49# set the environment variable LOCALMODCONFIG_DEBUG to get 50# debug output. 51my $debugprint = 0; 52$debugprint = 1 if (defined($ENV{LOCALMODCONFIG_DEBUG})); 53 54sub dprint { 55 return if (!$debugprint); 56 print STDERR @_; 57} 58 59my $uname = `uname -r`; 60chomp $uname; 61 62my @searchconfigs = ( 63 { 64 "file" => ".config", 65 "exec" => "cat", 66 }, 67 { 68 "file" => "/proc/config.gz", 69 "exec" => "zcat", 70 }, 71 { 72 "file" => "/boot/config-$uname", 73 "exec" => "cat", 74 }, 75 { 76 "file" => "/boot/vmlinuz-$uname", 77 "exec" => "scripts/extract-ikconfig", 78 "test" => "scripts/extract-ikconfig", 79 }, 80 { 81 "file" => "vmlinux", 82 "exec" => "scripts/extract-ikconfig", 83 "test" => "scripts/extract-ikconfig", 84 }, 85 { 86 "file" => "/lib/modules/$uname/kernel/kernel/configs.ko", 87 "exec" => "scripts/extract-ikconfig", 88 "test" => "scripts/extract-ikconfig", 89 }, 90 { 91 "file" => "kernel/configs.ko", 92 "exec" => "scripts/extract-ikconfig", 93 "test" => "scripts/extract-ikconfig", 94 }, 95 { 96 "file" => "kernel/configs.o", 97 "exec" => "scripts/extract-ikconfig", 98 "test" => "scripts/extract-ikconfig", 99 }, 100); 101 102sub read_config { 103 foreach my $conf (@searchconfigs) { 104 my $file = $conf->{"file"}; 105 106 next if ( ! -f "$file"); 107 108 if (defined($conf->{"test"})) { 109 `$conf->{"test"} $conf->{"file"} 2>/dev/null`; 110 next if ($?); 111 } 112 113 my $exec = $conf->{"exec"}; 114 115 print STDERR "using config: '$file'\n"; 116 117 open(my $infile, '-|', "$exec $file") || die "Failed to run $exec $file"; 118 my @x = <$infile>; 119 close $infile; 120 return @x; 121 } 122 die "No config file found"; 123} 124 125my @config_file = read_config; 126 127# Parse options 128my $localmodconfig = 0; 129my $localyesconfig = 0; 130 131GetOptions("localmodconfig" => \$localmodconfig, 132 "localyesconfig" => \$localyesconfig); 133 134# Get the build source and top level Kconfig file (passed in) 135my $ksource = ($ARGV[0] ? $ARGV[0] : '.'); 136my $kconfig = $ARGV[1]; 137my $lsmod_file = $ENV{'LSMOD'}; 138 139my @makefiles = `find $ksource -name Makefile -or -name Kbuild 2>/dev/null`; 140chomp @makefiles; 141 142my %depends; 143my %selects; 144my %prompts; 145my %objects; 146my %config2kfile; 147my $var; 148my $iflevel = 0; 149my @ifdeps; 150 151# prevent recursion 152my %read_kconfigs; 153 154sub read_kconfig { 155 my ($kconfig) = @_; 156 157 my $state = "NONE"; 158 my $config; 159 160 my $cont = 0; 161 my $line; 162 163 my $source = "$ksource/$kconfig"; 164 my $last_source = ""; 165 166 # Check for any environment variables used 167 while ($source =~ /\$\((\w+)\)/ && $last_source ne $source) { 168 my $env = $1; 169 $last_source = $source; 170 $source =~ s/\$\($env\)/$ENV{$env}/; 171 } 172 173 open(my $kinfile, '<', $source) || die "Can't open $kconfig"; 174 while (<$kinfile>) { 175 chomp; 176 177 # Make sure that lines ending with \ continue 178 if ($cont) { 179 $_ = $line . " " . $_; 180 } 181 182 if (s/\\$//) { 183 $cont = 1; 184 $line = $_; 185 next; 186 } 187 188 $cont = 0; 189 190 # collect any Kconfig sources 191 if (/^source\s+"?([^"]+)/) { 192 my $kconfig = $1; 193 # prevent reading twice. 194 if (!defined($read_kconfigs{$kconfig})) { 195 $read_kconfigs{$kconfig} = 1; 196 read_kconfig($kconfig); 197 } 198 next; 199 } 200 201 # configs found 202 if (/^\s*(menu)?config\s+(\S+)\s*$/) { 203 $state = "NEW"; 204 $config = $2; 205 $config2kfile{"CONFIG_$config"} = $kconfig; 206 207 # Add depends for 'if' nesting 208 for (my $i = 0; $i < $iflevel; $i++) { 209 if ($i) { 210 $depends{$config} .= " " . $ifdeps[$i]; 211 } else { 212 $depends{$config} = $ifdeps[$i]; 213 } 214 $state = "DEP"; 215 } 216 217 # collect the depends for the config 218 } elsif ($state eq "NEW" && /^\s*depends\s+on\s+(.*)$/) { 219 $state = "DEP"; 220 $depends{$config} = $1; 221 } elsif ($state eq "DEP" && /^\s*depends\s+on\s+(.*)$/) { 222 $depends{$config} .= " " . $1; 223 } elsif ($state eq "DEP" && /^\s*def(_(bool|tristate)|ault)\s+(\S.*)$/) { 224 my $dep = $3; 225 if ($dep !~ /^\s*(y|m|n)\s*$/) { 226 $dep =~ s/.*\sif\s+//; 227 $depends{$config} .= " " . $dep; 228 dprint "Added default depends $dep to $config\n"; 229 } 230 231 # Get the configs that select this config 232 } elsif ($state ne "NONE" && /^\s*select\s+(\S+)/) { 233 my $conf = $1; 234 if (defined($selects{$conf})) { 235 $selects{$conf} .= " " . $config; 236 } else { 237 $selects{$conf} = $config; 238 } 239 240 # configs without prompts must be selected 241 } elsif ($state ne "NONE" && /^\s*(tristate\s+\S|prompt\b)/) { 242 # note if the config has a prompt 243 $prompts{$config} = 1; 244 245 # Check for if statements 246 } elsif (/^if\s+(.*\S)\s*$/) { 247 my $deps = $1; 248 # remove beginning and ending non text 249 $deps =~ s/^[^a-zA-Z0-9_]*//; 250 $deps =~ s/[^a-zA-Z0-9_]*$//; 251 252 my @deps = split /[^a-zA-Z0-9_]+/, $deps; 253 254 $ifdeps[$iflevel++] = join ':', @deps; 255 256 } elsif (/^endif/) { 257 258 $iflevel-- if ($iflevel); 259 260 # stop on "help" and keywords that end a menu entry 261 } elsif (/^\s*(---)?help(---)?\s*$/ || /^(comment|choice|menu)\b/) { 262 $state = "NONE"; 263 } 264 } 265 close($kinfile); 266} 267 268if ($kconfig) { 269 read_kconfig($kconfig); 270} 271 272# Makefiles can use variables to define their dependencies 273sub convert_vars { 274 my ($line, %vars) = @_; 275 276 my $process = ""; 277 278 while ($line =~ s/^(.*?)(\$\((.*?)\))//) { 279 my $start = $1; 280 my $variable = $2; 281 my $var = $3; 282 283 if (defined($vars{$var})) { 284 $process .= $start . $vars{$var}; 285 } else { 286 $process .= $start . $variable; 287 } 288 } 289 290 $process .= $line; 291 292 return $process; 293} 294 295# Read all Makefiles to map the configs to the objects 296foreach my $makefile (@makefiles) { 297 298 my $line = ""; 299 my %make_vars; 300 301 open(my $infile, '<', $makefile) || die "Can't open $makefile"; 302 while (<$infile>) { 303 # if this line ends with a backslash, continue 304 chomp; 305 if (/^(.*)\\$/) { 306 $line .= $1; 307 next; 308 } 309 310 $line .= $_; 311 $_ = $line; 312 $line = ""; 313 314 my $objs; 315 316 # Convert variables in a line (could define configs) 317 $_ = convert_vars($_, %make_vars); 318 319 # collect objects after obj-$(CONFIG_FOO_BAR) 320 if (/obj-\$\((CONFIG_[^\)]*)\)\s*[+:]?=\s*(.*)/) { 321 $var = $1; 322 $objs = $2; 323 324 # check if variables are set 325 } elsif (/^\s*(\S+)\s*[:]?=\s*(.*\S)/) { 326 $make_vars{$1} = $2; 327 } 328 if (defined($objs)) { 329 foreach my $obj (split /\s+/,$objs) { 330 $obj =~ s/-/_/g; 331 if ($obj =~ /(.*)\.o$/) { 332 # Objects may be enabled by more than one config. 333 # Store configs in an array. 334 my @arr; 335 336 if (defined($objects{$1})) { 337 @arr = @{$objects{$1}}; 338 } 339 340 $arr[$#arr+1] = $var; 341 342 # The objects have a hash mapping to a reference 343 # of an array of configs. 344 $objects{$1} = \@arr; 345 } 346 } 347 } 348 } 349 close($infile); 350} 351 352my %modules; 353my $linfile; 354 355if (defined($lsmod_file)) { 356 if ( ! -f $lsmod_file) { 357 if ( -f $ENV{'objtree'}."/".$lsmod_file) { 358 $lsmod_file = $ENV{'objtree'}."/".$lsmod_file; 359 } else { 360 die "$lsmod_file not found"; 361 } 362 } 363 364 my $otype = ( -x $lsmod_file) ? '-|' : '<'; 365 open($linfile, $otype, $lsmod_file); 366 367} else { 368 369 # see what modules are loaded on this system 370 my $lsmod; 371 372 foreach my $dir ( ("/sbin", "/bin", "/usr/sbin", "/usr/bin") ) { 373 if ( -x "$dir/lsmod" ) { 374 $lsmod = "$dir/lsmod"; 375 last; 376 } 377 } 378 if (!defined($lsmod)) { 379 # try just the path 380 $lsmod = "lsmod"; 381 } 382 383 open($linfile, '-|', $lsmod) || die "Can not call lsmod with $lsmod"; 384} 385 386while (<$linfile>) { 387 next if (/^Module/); # Skip the first line. 388 if (/^(\S+)/) { 389 $modules{$1} = 1; 390 } 391} 392close ($linfile); 393 394# add to the configs hash all configs that are needed to enable 395# a loaded module. This is a direct obj-${CONFIG_FOO} += bar.o 396# where we know we need bar.o so we add FOO to the list. 397my %configs; 398foreach my $module (keys(%modules)) { 399 if (defined($objects{$module})) { 400 my @arr = @{$objects{$module}}; 401 foreach my $conf (@arr) { 402 $configs{$conf} = $module; 403 dprint "$conf added by direct ($module)\n"; 404 if ($debugprint) { 405 my $c=$conf; 406 $c =~ s/^CONFIG_//; 407 if (defined($depends{$c})) { 408 dprint " deps = $depends{$c}\n"; 409 } else { 410 dprint " no deps\n"; 411 } 412 } 413 } 414 } else { 415 # Most likely, someone has a custom (binary?) module loaded. 416 print STDERR "$module config not found!!\n"; 417 } 418} 419 420# Read the current config, and see what is enabled. We want to 421# ignore configs that we would not enable anyway. 422 423my %orig_configs; 424my $valid = "A-Za-z_0-9"; 425 426foreach my $line (@config_file) { 427 $_ = $line; 428 429 if (/(CONFIG_[$valid]*)=(m|y)/) { 430 $orig_configs{$1} = $2; 431 } 432} 433 434my $repeat = 1; 435 436my $depconfig; 437 438# 439# Note, we do not care about operands (like: &&, ||, !) we want to add any 440# config that is in the depend list of another config. This script does 441# not enable configs that are not already enabled. If we come across a 442# config A that depends on !B, we can still add B to the list of depends 443# to keep on. If A was on in the original config, B would not have been 444# and B would not be turned on by this script. 445# 446sub parse_config_depends 447{ 448 my ($p) = @_; 449 450 while ($p =~ /[$valid]/) { 451 452 if ($p =~ /^[^$valid]*([$valid]+)/) { 453 my $conf = "CONFIG_" . $1; 454 455 $p =~ s/^[^$valid]*[$valid]+//; 456 457 # We only need to process if the depend config is a module 458 if (!defined($orig_configs{$conf}) || $orig_configs{$conf} eq "y") { 459 next; 460 } 461 462 if (!defined($configs{$conf})) { 463 # We must make sure that this config has its 464 # dependencies met. 465 $repeat = 1; # do again 466 dprint "$conf selected by depend $depconfig\n"; 467 $configs{$conf} = 1; 468 } 469 } else { 470 die "this should never happen"; 471 } 472 } 473} 474 475# Select is treated a bit differently than depends. We call this 476# when a config has no prompt and requires another config to be 477# selected. We use to just select all configs that selected this 478# config, but found that that can balloon into enabling hundreds 479# of configs that we do not care about. 480# 481# The idea is we look at all the configs that select it. If one 482# is already in our list of configs to enable, then there's nothing 483# else to do. If there isn't, we pick the first config that was 484# enabled in the original config and use that. 485sub parse_config_selects 486{ 487 my ($config, $p) = @_; 488 489 my $next_config; 490 491 while ($p =~ /[$valid]/) { 492 493 if ($p =~ /^[^$valid]*([$valid]+)/) { 494 my $conf = "CONFIG_" . $1; 495 496 $p =~ s/^[^$valid]*[$valid]+//; 497 498 # Make sure that this config exists in the current .config file 499 if (!defined($orig_configs{$conf})) { 500 dprint "$conf not set for $config select\n"; 501 next; 502 } 503 504 # Check if something other than a module selects this config 505 if (defined($orig_configs{$conf}) && $orig_configs{$conf} ne "m") { 506 dprint "$conf (non module) selects config, we are good\n"; 507 # we are good with this 508 return; 509 } 510 if (defined($configs{$conf})) { 511 dprint "$conf selects $config so we are good\n"; 512 # A set config selects this config, we are good 513 return; 514 } 515 # Set this config to be selected 516 if (!defined($next_config)) { 517 $next_config = $conf; 518 } 519 } else { 520 die "this should never happen"; 521 } 522 } 523 524 # If no possible config selected this, then something happened. 525 if (!defined($next_config)) { 526 print STDERR "WARNING: $config is required, but nothing in the\n"; 527 print STDERR " current config selects it.\n"; 528 return; 529 } 530 531 # If we are here, then we found no config that is set and 532 # selects this config. Repeat. 533 $repeat = 1; 534 # Make this config need to be selected 535 $configs{$next_config} = 1; 536 dprint "$next_config selected by select $config\n"; 537} 538 539my %process_selects; 540 541# loop through all configs, select their dependencies. 542sub loop_depend { 543 $repeat = 1; 544 545 while ($repeat) { 546 $repeat = 0; 547 548 forloop: 549 foreach my $config (keys %configs) { 550 551 # If this config is not a module, we do not need to process it 552 if (defined($orig_configs{$config}) && $orig_configs{$config} ne "m") { 553 next forloop; 554 } 555 556 $config =~ s/^CONFIG_//; 557 $depconfig = $config; 558 559 if (defined($depends{$config})) { 560 # This config has dependencies. Make sure they are also included 561 parse_config_depends $depends{$config}; 562 } 563 564 # If the config has no prompt, then we need to check if a config 565 # that is enabled selected it. Or if we need to enable one. 566 if (!defined($prompts{$config}) && defined($selects{$config})) { 567 $process_selects{$config} = 1; 568 } 569 } 570 } 571} 572 573sub loop_select { 574 575 foreach my $config (keys %process_selects) { 576 $config =~ s/^CONFIG_//; 577 578 dprint "Process select $config\n"; 579 580 # config has no prompt and must be selected. 581 parse_config_selects $config, $selects{$config}; 582 } 583} 584 585while ($repeat) { 586 # Get the first set of configs and their dependencies. 587 loop_depend; 588 589 $repeat = 0; 590 591 # Now we need to see if we have to check selects; 592 loop_select; 593} 594 595my %setconfigs; 596my @preserved_kconfigs; 597if (defined($ENV{'LMC_KEEP'})) { 598 @preserved_kconfigs = split(/:/,$ENV{LMC_KEEP}); 599} 600 601sub in_preserved_kconfigs { 602 my $kconfig = $config2kfile{$_[0]}; 603 if (!defined($kconfig)) { 604 return 0; 605 } 606 foreach my $excl (@preserved_kconfigs) { 607 if($kconfig =~ /^$excl/) { 608 return 1; 609 } 610 } 611 return 0; 612} 613 614# Finally, read the .config file and turn off any module enabled that 615# we could not find a reason to keep enabled. 616foreach my $line (@config_file) { 617 $_ = $line; 618 619 if (/CONFIG_IKCONFIG/) { 620 if (/# CONFIG_IKCONFIG is not set/) { 621 # enable IKCONFIG at least as a module 622 print "CONFIG_IKCONFIG=m\n"; 623 # don't ask about PROC 624 print "# CONFIG_IKCONFIG_PROC is not set\n"; 625 } else { 626 print; 627 } 628 next; 629 } 630 631 if (/CONFIG_MODULE_SIG_KEY="(.+)"/) { 632 my $orig_cert = $1; 633 my $default_cert = "certs/signing_key.pem"; 634 635 # Check that the logic in this script still matches the one in Kconfig 636 if (!defined($depends{"MODULE_SIG_KEY"}) || 637 $depends{"MODULE_SIG_KEY"} !~ /"\Q$default_cert\E"/) { 638 print STDERR "WARNING: MODULE_SIG_KEY assertion failure, ", 639 "update needed to ", __FILE__, " line ", __LINE__, "\n"; 640 print; 641 } elsif ($orig_cert ne $default_cert && ! -f $orig_cert) { 642 print STDERR "Module signature verification enabled but ", 643 "module signing key \"$orig_cert\" not found. Resetting ", 644 "signing key to default value.\n"; 645 print "CONFIG_MODULE_SIG_KEY=\"$default_cert\"\n"; 646 } else { 647 print; 648 } 649 next; 650 } 651 652 if (/CONFIG_SYSTEM_TRUSTED_KEYS="(.+)"/) { 653 my $orig_keys = $1; 654 655 if (! -f $orig_keys) { 656 print STDERR "System keyring enabled but keys \"$orig_keys\" ", 657 "not found. Resetting keys to default value.\n"; 658 print "CONFIG_SYSTEM_TRUSTED_KEYS=\"\"\n"; 659 } else { 660 print; 661 } 662 next; 663 } 664 665 if (/^(CONFIG.*)=(m|y)/) { 666 if (in_preserved_kconfigs($1)) { 667 dprint "Preserve config $1"; 668 print; 669 next; 670 } 671 if (defined($configs{$1})) { 672 if ($localyesconfig) { 673 $setconfigs{$1} = 'y'; 674 print "$1=y\n"; 675 next; 676 } else { 677 $setconfigs{$1} = $2; 678 } 679 } elsif ($2 eq "m") { 680 print "# $1 is not set\n"; 681 next; 682 } 683 } 684 print; 685} 686 687# Integrity check, make sure all modules that we want enabled do 688# indeed have their configs set. 689loop: 690foreach my $module (keys(%modules)) { 691 if (defined($objects{$module})) { 692 my @arr = @{$objects{$module}}; 693 foreach my $conf (@arr) { 694 if (defined($setconfigs{$conf})) { 695 next loop; 696 } 697 } 698 print STDERR "module $module did not have configs"; 699 foreach my $conf (@arr) { 700 print STDERR " " , $conf; 701 } 702 print STDERR "\n"; 703 } 704} 705