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 %defaults; 148my %types; 149my $var; 150my $iflevel = 0; 151my @ifdeps; 152 153# prevent recursion 154my %read_kconfigs; 155 156sub read_kconfig { 157 my ($kconfig) = @_; 158 159 my $state = "NONE"; 160 my $config; 161 162 my $cont = 0; 163 my $line; 164 165 my $source = "$ksource/$kconfig"; 166 my $last_source = ""; 167 168 # Check for any environment variables used 169 while ($source =~ /\$\((\w+)\)/ && $last_source ne $source) { 170 my $env = $1; 171 $last_source = $source; 172 $source =~ s/\$\($env\)/$ENV{$env}/; 173 } 174 175 open(my $kinfile, '<', $source) || die "Can't open $source"; 176 while (<$kinfile>) { 177 chomp; 178 179 # Make sure that lines ending with \ continue 180 if ($cont) { 181 $_ = $line . " " . $_; 182 } 183 184 if (s/\\$//) { 185 $cont = 1; 186 $line = $_; 187 next; 188 } 189 190 $cont = 0; 191 192 # collect any Kconfig sources 193 if (/^source\s+"?([^"]+)/) { 194 my $kconfig = $1; 195 # prevent reading twice. 196 if (!defined($read_kconfigs{$kconfig})) { 197 $read_kconfigs{$kconfig} = 1; 198 read_kconfig($kconfig); 199 } 200 next; 201 } 202 203 # configs found 204 if (/^\s*(menu)?config\s+(\S+)\s*$/) { 205 $state = "NEW"; 206 $config = $2; 207 $config2kfile{"CONFIG_$config"} = $kconfig; 208 209 # Add depends for 'if' nesting 210 for (my $i = 0; $i < $iflevel; $i++) { 211 if ($i) { 212 $depends{$config} .= " " . $ifdeps[$i]; 213 } else { 214 $depends{$config} = $ifdeps[$i]; 215 } 216 $state = "DEP"; 217 } 218 219 # collect the depends for the config 220 } elsif ($state eq "NEW" && /^\s*depends\s+on\s+(.*)$/) { 221 $state = "DEP"; 222 $depends{$config} = $1; 223 } elsif ($state eq "DEP" && /^\s*depends\s+on\s+(.*)$/) { 224 $depends{$config} .= " " . $1; 225 } elsif ($state ne "NONE" && /^\s*def(_(bool|tristate)|ault)\s+(\S.*)$/) { 226 my $dep = $3; 227 $defaults{$config} = 1; 228 $types{$config} = $2 if (defined($2)); 229 if ($dep !~ /^\s*(y|m|n)\s*$/) { 230 $dep =~ s/.*\sif\s+//; 231 $depends{$config} .= " " . $dep; 232 dprint "Added default depends $dep to $config\n"; 233 } 234 235 # Get the configs that select this config 236 } elsif ($state ne "NONE" && /^\s*select\s+(\S+)/) { 237 my $conf = $1; 238 if (defined($selects{$conf})) { 239 $selects{$conf} .= " " . $config; 240 } else { 241 $selects{$conf} = $config; 242 } 243 244 # configs without prompts must be selected 245 } elsif ($state ne "NONE" && /^\s*(bool|boolean)(\s+\S.*)?$/) { 246 $types{$config} = "bool"; 247 $prompts{$config} = 1 if (defined($2)); 248 } elsif ($state ne "NONE" && /^\s*tristate(\s+\S.*)?$/) { 249 $types{$config} = "tristate"; 250 $prompts{$config} = 1 if (defined($1)); 251 } elsif ($state ne "NONE" && /^\s*prompt\b/) { 252 # note if the config has a prompt 253 $prompts{$config} = 1; 254 255 # Check for if statements 256 } elsif (/^if\s+(.*\S)\s*$/) { 257 my $deps = $1; 258 # remove beginning and ending non text 259 $deps =~ s/^[^a-zA-Z0-9_]*//; 260 $deps =~ s/[^a-zA-Z0-9_]*$//; 261 262 my @deps = split /[^a-zA-Z0-9_]+/, $deps; 263 264 $ifdeps[$iflevel++] = join ':', @deps; 265 266 } elsif (/^endif/) { 267 268 $iflevel-- if ($iflevel); 269 270 # stop on "help" and keywords that end a menu entry 271 } elsif (/^\s*(---)?help(---)?\s*$/ || /^(comment|choice|menu)\b/) { 272 $state = "NONE"; 273 } 274 } 275 close($kinfile); 276} 277 278if ($kconfig) { 279 read_kconfig($kconfig); 280} 281 282# Makefiles can use variables to define their dependencies 283sub convert_vars { 284 my ($line, %vars) = @_; 285 286 my $process = ""; 287 288 while ($line =~ s/^(.*?)(\$\((.*?)\))//) { 289 my $start = $1; 290 my $variable = $2; 291 my $var = $3; 292 293 if (defined($vars{$var})) { 294 $process .= $start . $vars{$var}; 295 } else { 296 $process .= $start . $variable; 297 } 298 } 299 300 $process .= $line; 301 302 return $process; 303} 304 305# Read all Makefiles to map the configs to the objects 306foreach my $makefile (@makefiles) { 307 308 my $line = ""; 309 my %make_vars; 310 311 open(my $infile, '<', $makefile) || die "Can't open $makefile"; 312 while (<$infile>) { 313 # if this line ends with a backslash, continue 314 chomp; 315 if (/^(.*)\\$/) { 316 $line .= $1; 317 next; 318 } 319 320 $line .= $_; 321 $_ = $line; 322 $line = ""; 323 324 my $objs; 325 326 # Convert variables in a line (could define configs) 327 $_ = convert_vars($_, %make_vars); 328 329 # collect objects after obj-$(CONFIG_FOO_BAR) 330 if (/obj-\$[({](CONFIG_[^})]*)[)}]\s*[+:]?=\s*(.*)/) { 331 $var = $1; 332 $objs = $2; 333 334 # check if variables are set 335 } elsif (/^\s*(\S+)\s*[:]?=\s*(.*\S)/) { 336 $make_vars{$1} = $2; 337 } 338 if (defined($objs)) { 339 foreach my $obj (split /\s+/,$objs) { 340 $obj =~ s/-/_/g; 341 if ($obj =~ /(.*)\.o$/) { 342 # Objects may be enabled by more than one config. 343 # Store configs in an array. 344 my @arr; 345 346 if (defined($objects{$1})) { 347 @arr = @{$objects{$1}}; 348 } 349 350 $arr[$#arr+1] = $var; 351 352 # The objects have a hash mapping to a reference 353 # of an array of configs. 354 $objects{$1} = \@arr; 355 } 356 } 357 } 358 } 359 close($infile); 360} 361 362my %modules; 363my $linfile; 364 365if (defined($lsmod_file)) { 366 if ( ! -f $lsmod_file) { 367 if ( -f $ENV{'objtree'}."/".$lsmod_file) { 368 $lsmod_file = $ENV{'objtree'}."/".$lsmod_file; 369 } else { 370 die "$lsmod_file not found"; 371 } 372 } 373 374 my $otype = ( -x $lsmod_file) ? '-|' : '<'; 375 open($linfile, $otype, $lsmod_file); 376 377} else { 378 379 # see what modules are loaded on this system 380 my $lsmod; 381 382 foreach my $dir ( ("/sbin", "/bin", "/usr/sbin", "/usr/bin") ) { 383 if ( -x "$dir/lsmod" ) { 384 $lsmod = "$dir/lsmod"; 385 last; 386 } 387 } 388 if (!defined($lsmod)) { 389 # try just the path 390 $lsmod = "lsmod"; 391 } 392 393 open($linfile, '-|', $lsmod) || die "Can not call lsmod with $lsmod"; 394} 395 396while (<$linfile>) { 397 next if (/^Module/); # Skip the first line. 398 if (/^(\S+)/) { 399 $modules{$1} = 1; 400 } 401} 402close ($linfile); 403 404# add to the configs hash all configs that are needed to enable 405# a loaded module. This is a direct obj-${CONFIG_FOO} += bar.o 406# where we know we need bar.o so we add FOO to the list. 407my %configs; 408foreach my $module (keys(%modules)) { 409 if (defined($objects{$module})) { 410 my @arr = @{$objects{$module}}; 411 foreach my $conf (@arr) { 412 $configs{$conf} = $module; 413 dprint "$conf added by direct ($module)\n"; 414 if ($debugprint) { 415 my $c=$conf; 416 $c =~ s/^CONFIG_//; 417 if (defined($depends{$c})) { 418 dprint " deps = $depends{$c}\n"; 419 } else { 420 dprint " no deps\n"; 421 } 422 } 423 } 424 } else { 425 # Most likely, someone has a custom (binary?) module loaded. 426 print STDERR "$module config not found!\n"; 427 } 428} 429 430# Read the current config, and see what is enabled. We want to 431# ignore configs that we would not enable anyway. 432 433my %orig_configs; 434my $valid = "A-Za-z_0-9"; 435 436foreach my $line (@config_file) { 437 $_ = $line; 438 439 if (/(CONFIG_[$valid]*)=(m|y)/) { 440 $orig_configs{$1} = $2; 441 } 442} 443 444my $repeat = 1; 445 446my $depconfig; 447 448# 449# Note, we do not care about operands (like: &&, ||, !) we want to add any 450# config that is in the depend list of another config. This script does 451# not enable configs that are not already enabled. If we come across a 452# config A that depends on !B, we can still add B to the list of depends 453# to keep on. If A was on in the original config, B would not have been 454# and B would not be turned on by this script. 455# 456sub parse_config_depends 457{ 458 my ($p) = @_; 459 460 while ($p =~ /[$valid]/) { 461 462 if ($p =~ /^[^$valid]*([$valid]+)/) { 463 my $conf = "CONFIG_" . $1; 464 465 $p =~ s/^[^$valid]*[$valid]+//; 466 467 # We only need to process if the depend config is a module 468 if (!defined($orig_configs{$conf}) || $orig_configs{$conf} eq "y") { 469 next; 470 } 471 472 if (!defined($configs{$conf})) { 473 # We must make sure that this config has its 474 # dependencies met. 475 $repeat = 1; # do again 476 dprint "$conf selected by depend $depconfig\n"; 477 $configs{$conf} = 1; 478 } 479 } else { 480 die "this should never happen"; 481 } 482 } 483} 484 485# Select is treated a bit differently than depends. We call this 486# when a config has no prompt and requires another config to be 487# selected. We use to just select all configs that selected this 488# config, but found that that can balloon into enabling hundreds 489# of configs that we do not care about. 490# 491# The idea is we look at all the configs that select it. If one 492# is already in our list of configs to enable, then there's nothing 493# else to do. If there isn't, we pick the first config that was 494# enabled in the original config and use that. 495sub parse_config_selects 496{ 497 my ($config, $p) = @_; 498 499 my $next_config; 500 501 while ($p =~ /[$valid]/) { 502 503 if ($p =~ /^[^$valid]*([$valid]+)/) { 504 my $conf = "CONFIG_" . $1; 505 506 $p =~ s/^[^$valid]*[$valid]+//; 507 508 # Make sure that this config exists in the current .config file 509 if (!defined($orig_configs{$conf})) { 510 dprint "$conf not set for $config select\n"; 511 next; 512 } 513 514 # Check if something other than a module selects this config 515 if (defined($orig_configs{$conf}) && $orig_configs{$conf} ne "m") { 516 dprint "$conf (non module) selects $config, we are good\n"; 517 # we are good with this 518 return; 519 } 520 if (defined($configs{$conf})) { 521 dprint "$conf selects $config so we are good\n"; 522 # A set config selects this config, we are good 523 return; 524 } 525 # Set this config to be selected 526 if (!defined($next_config)) { 527 $next_config = $conf; 528 } 529 } else { 530 die "this should never happen"; 531 } 532 } 533 534 # If no possible config selected this, then something happened. 535 if (!defined($next_config)) { 536 537 # Some config options have no prompt, and nothing selects them, but 538 # they stay turned on once the final checks for the configs 539 # are done. These configs have a default option, so turn off the 540 # warnings for configs with default options. 541 if (!defined($defaults{$config})) { 542 print STDERR "WARNING: $config is required, but nothing in the\n"; 543 print STDERR " current config selects it.\n"; 544 } 545 546 return; 547 } 548 549 # If we are here, then we found no config that is set and 550 # selects this config. Repeat. 551 $repeat = 1; 552 # Make this config need to be selected 553 $configs{$next_config} = 1; 554 dprint "$next_config selected by select $config\n"; 555} 556 557my %process_selects; 558 559# loop through all configs, select their dependencies. 560sub loop_depend { 561 $repeat = 1; 562 563 while ($repeat) { 564 $repeat = 0; 565 566 forloop: 567 foreach my $config (keys %configs) { 568 569 # If this config is not a module, we do not need to process it 570 if (defined($orig_configs{$config}) && $orig_configs{$config} ne "m") { 571 next forloop; 572 } 573 574 $config =~ s/^CONFIG_//; 575 $depconfig = $config; 576 577 if (defined($depends{$config})) { 578 # This config has dependencies. Make sure they are also included 579 parse_config_depends $depends{$config}; 580 } 581 582 # If the config has no prompt, then we need to check if a config 583 # that is enabled selected it. Or if we need to enable one. 584 if (!defined($prompts{$config}) && defined($selects{$config})) { 585 $process_selects{$config} = 1; 586 } 587 } 588 } 589} 590 591sub loop_select { 592 593 foreach my $config (keys %process_selects) { 594 $config =~ s/^CONFIG_//; 595 596 dprint "Process select $config\n"; 597 598 # config has no prompt and must be selected. 599 parse_config_selects $config, $selects{$config}; 600 } 601} 602 603while ($repeat) { 604 # Get the first set of configs and their dependencies. 605 loop_depend; 606 607 $repeat = 0; 608 609 # Now we need to see if we have to check selects; 610 loop_select; 611} 612 613my %setconfigs; 614my @preserved_kconfigs; 615if (defined($ENV{'LMC_KEEP'})) { 616 @preserved_kconfigs = split(/:/,$ENV{LMC_KEEP}); 617} 618 619sub in_preserved_kconfigs { 620 my $kconfig = $config2kfile{$_[0]}; 621 if (!defined($kconfig)) { 622 return 0; 623 } 624 foreach my $excl (@preserved_kconfigs) { 625 if($kconfig =~ /^$excl/) { 626 return 1; 627 } 628 } 629 return 0; 630} 631 632# Finally, read the .config file and turn off any module enabled that 633# we could not find a reason to keep enabled. 634foreach my $line (@config_file) { 635 $_ = $line; 636 637 if (/CONFIG_IKCONFIG/) { 638 if (/# CONFIG_IKCONFIG is not set/) { 639 # enable IKCONFIG at least as a module 640 print "CONFIG_IKCONFIG=m\n"; 641 # don't ask about PROC 642 print "# CONFIG_IKCONFIG_PROC is not set\n"; 643 } else { 644 print; 645 } 646 next; 647 } 648 649 if (/CONFIG_MODULE_SIG_KEY="(.+)"/) { 650 my $orig_cert = $1; 651 my $default_cert = "certs/signing_key.pem"; 652 653 # Check that the logic in this script still matches the one in Kconfig 654 if (!defined($depends{"MODULE_SIG_KEY"}) || 655 $depends{"MODULE_SIG_KEY"} !~ /"\Q$default_cert\E"/) { 656 print STDERR "WARNING: MODULE_SIG_KEY assertion failure, ", 657 "update needed to ", __FILE__, " line ", __LINE__, "\n"; 658 print; 659 } elsif ($orig_cert ne $default_cert && ! -f $orig_cert) { 660 print STDERR "Module signature verification enabled but ", 661 "module signing key \"$orig_cert\" not found. Resetting ", 662 "signing key to default value.\n"; 663 print "CONFIG_MODULE_SIG_KEY=\"$default_cert\"\n"; 664 } else { 665 print; 666 } 667 next; 668 } 669 670 if (/CONFIG_SYSTEM_TRUSTED_KEYS="(.+)"/) { 671 my $orig_keys = $1; 672 673 if (! -f $orig_keys) { 674 print STDERR "System keyring enabled but keys \"$orig_keys\" ", 675 "not found. Resetting keys to default value.\n"; 676 print "CONFIG_SYSTEM_TRUSTED_KEYS=\"\"\n"; 677 } else { 678 print; 679 } 680 next; 681 } 682 683 if (/^(CONFIG.*)=(m|y)/) { 684 if (in_preserved_kconfigs($1)) { 685 dprint "Preserve config $1"; 686 print; 687 next; 688 } 689 if (defined($configs{$1})) { 690 if ($localyesconfig) { 691 $setconfigs{$1} = 'y'; 692 print "$1=y\n"; 693 next; 694 } else { 695 $setconfigs{$1} = $2; 696 } 697 } elsif ($2 eq "m") { 698 print "# $1 is not set\n"; 699 next; 700 } 701 } 702 print; 703} 704 705# Integrity check, make sure all modules that we want enabled do 706# indeed have their configs set. 707loop: 708foreach my $module (keys(%modules)) { 709 if (defined($objects{$module})) { 710 my @arr = @{$objects{$module}}; 711 foreach my $conf (@arr) { 712 if (defined($setconfigs{$conf})) { 713 next loop; 714 } 715 } 716 print STDERR "module $module did not have configs"; 717 foreach my $conf (@arr) { 718 my $c = $conf; 719 $c =~ s/^CONFIG_//; 720 if (!$localyesconfig && defined($types{$c}) && $types{$c} eq "bool") { 721 print STDERR " $conf (boolean, not supported with =m)"; 722 } elsif (defined($types{$c})) { 723 print STDERR " $conf ($types{$c})"; 724 } else { 725 print STDERR " " , $conf; 726 } 727 } 728 print STDERR "\n"; 729 } 730} 731 732# vim: softtabstop=4 733