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