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 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 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 $var; 147my $iflevel = 0; 148my @ifdeps; 149 150# prevent recursion 151my %read_kconfigs; 152 153sub read_kconfig { 154 my ($kconfig) = @_; 155 156 my $state = "NONE"; 157 my $config; 158 159 my $cont = 0; 160 my $line; 161 162 my $source = "$ksource/$kconfig"; 163 my $last_source = ""; 164 165 # Check for any environment variables used 166 while ($source =~ /\$\((\w+)\)/ && $last_source ne $source) { 167 my $env = $1; 168 $last_source = $source; 169 $source =~ s/\$\($env\)/$ENV{$env}/; 170 } 171 172 open(my $kinfile, '<', $source) || die "Can't open $kconfig"; 173 while (<$kinfile>) { 174 chomp; 175 176 # Make sure that lines ending with \ continue 177 if ($cont) { 178 $_ = $line . " " . $_; 179 } 180 181 if (s/\\$//) { 182 $cont = 1; 183 $line = $_; 184 next; 185 } 186 187 $cont = 0; 188 189 # collect any Kconfig sources 190 if (/^source\s+"?([^"]+)/) { 191 my $kconfig = $1; 192 # prevent reading twice. 193 if (!defined($read_kconfigs{$kconfig})) { 194 $read_kconfigs{$kconfig} = 1; 195 read_kconfig($kconfig); 196 } 197 next; 198 } 199 200 # configs found 201 if (/^\s*(menu)?config\s+(\S+)\s*$/) { 202 $state = "NEW"; 203 $config = $2; 204 205 # Add depends for 'if' nesting 206 for (my $i = 0; $i < $iflevel; $i++) { 207 if ($i) { 208 $depends{$config} .= " " . $ifdeps[$i]; 209 } else { 210 $depends{$config} = $ifdeps[$i]; 211 } 212 $state = "DEP"; 213 } 214 215 # collect the depends for the config 216 } elsif ($state eq "NEW" && /^\s*depends\s+on\s+(.*)$/) { 217 $state = "DEP"; 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.*)$/) { 222 my $dep = $3; 223 if ($dep !~ /^\s*(y|m|n)\s*$/) { 224 $dep =~ s/.*\sif\s+//; 225 $depends{$config} .= " " . $dep; 226 dprint "Added default depends $dep to $config\n"; 227 } 228 229 # Get the configs that select this config 230 } elsif ($state ne "NONE" && /^\s*select\s+(\S+)/) { 231 my $conf = $1; 232 if (defined($selects{$conf})) { 233 $selects{$conf} .= " " . $config; 234 } else { 235 $selects{$conf} = $config; 236 } 237 238 # configs without prompts must be selected 239 } elsif ($state ne "NONE" && /^\s*(tristate\s+\S|prompt\b)/) { 240 # note if the config has a prompt 241 $prompts{$config} = 1; 242 243 # Check for if statements 244 } elsif (/^if\s+(.*\S)\s*$/) { 245 my $deps = $1; 246 # remove beginning and ending non text 247 $deps =~ s/^[^a-zA-Z0-9_]*//; 248 $deps =~ s/[^a-zA-Z0-9_]*$//; 249 250 my @deps = split /[^a-zA-Z0-9_]+/, $deps; 251 252 $ifdeps[$iflevel++] = join ':', @deps; 253 254 } elsif (/^endif/) { 255 256 $iflevel-- if ($iflevel); 257 258 # stop on "help" and keywords that end a menu entry 259 } elsif (/^\s*(---)?help(---)?\s*$/ || /^(comment|choice|menu)\b/) { 260 $state = "NONE"; 261 } 262 } 263 close($kinfile); 264} 265 266if ($kconfig) { 267 read_kconfig($kconfig); 268} 269 270# Makefiles can use variables to define their dependencies 271sub convert_vars { 272 my ($line, %vars) = @_; 273 274 my $process = ""; 275 276 while ($line =~ s/^(.*?)(\$\((.*?)\))//) { 277 my $start = $1; 278 my $variable = $2; 279 my $var = $3; 280 281 if (defined($vars{$var})) { 282 $process .= $start . $vars{$var}; 283 } else { 284 $process .= $start . $variable; 285 } 286 } 287 288 $process .= $line; 289 290 return $process; 291} 292 293# Read all Makefiles to map the configs to the objects 294foreach my $makefile (@makefiles) { 295 296 my $line = ""; 297 my %make_vars; 298 299 open(my $infile, '<', $makefile) || die "Can't open $makefile"; 300 while (<$infile>) { 301 # if this line ends with a backslash, continue 302 chomp; 303 if (/^(.*)\\$/) { 304 $line .= $1; 305 next; 306 } 307 308 $line .= $_; 309 $_ = $line; 310 $line = ""; 311 312 my $objs; 313 314 # Convert variables in a line (could define configs) 315 $_ = convert_vars($_, %make_vars); 316 317 # collect objects after obj-$(CONFIG_FOO_BAR) 318 if (/obj-\$\((CONFIG_[^\)]*)\)\s*[+:]?=\s*(.*)/) { 319 $var = $1; 320 $objs = $2; 321 322 # check if variables are set 323 } elsif (/^\s*(\S+)\s*[:]?=\s*(.*\S)/) { 324 $make_vars{$1} = $2; 325 } 326 if (defined($objs)) { 327 foreach my $obj (split /\s+/,$objs) { 328 $obj =~ s/-/_/g; 329 if ($obj =~ /(.*)\.o$/) { 330 # Objects may be enabled by more than one config. 331 # Store configs in an array. 332 my @arr; 333 334 if (defined($objects{$1})) { 335 @arr = @{$objects{$1}}; 336 } 337 338 $arr[$#arr+1] = $var; 339 340 # The objects have a hash mapping to a reference 341 # of an array of configs. 342 $objects{$1} = \@arr; 343 } 344 } 345 } 346 } 347 close($infile); 348} 349 350my %modules; 351my $linfile; 352 353if (defined($lsmod_file)) { 354 if ( ! -f $lsmod_file) { 355 if ( -f $ENV{'objtree'}."/".$lsmod_file) { 356 $lsmod_file = $ENV{'objtree'}."/".$lsmod_file; 357 } else { 358 die "$lsmod_file not found"; 359 } 360 } 361 362 my $otype = ( -x $lsmod_file) ? '-|' : '<'; 363 open($linfile, $otype, $lsmod_file); 364 365} else { 366 367 # see what modules are loaded on this system 368 my $lsmod; 369 370 foreach my $dir ( ("/sbin", "/bin", "/usr/sbin", "/usr/bin") ) { 371 if ( -x "$dir/lsmod" ) { 372 $lsmod = "$dir/lsmod"; 373 last; 374 } 375 } 376 if (!defined($lsmod)) { 377 # try just the path 378 $lsmod = "lsmod"; 379 } 380 381 open($linfile, '-|', $lsmod) || die "Can not call lsmod with $lsmod"; 382} 383 384while (<$linfile>) { 385 next if (/^Module/); # Skip the first line. 386 if (/^(\S+)/) { 387 $modules{$1} = 1; 388 } 389} 390close ($linfile); 391 392# 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. 395my %configs; 396foreach 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 ($module)\n"; 402 if ($debugprint) { 403 my $c=$conf; 404 $c =~ s/^CONFIG_//; 405 if (defined($depends{$c})) { 406 dprint " deps = $depends{$c}\n"; 407 } else { 408 dprint " no deps\n"; 409 } 410 } 411 } 412 } else { 413 # Most likely, someone has a custom (binary?) module loaded. 414 print STDERR "$module config not found!!\n"; 415 } 416} 417 418# Read the current config, and see what is enabled. We want to 419# ignore configs that we would not enable anyway. 420 421my %orig_configs; 422my $valid = "A-Za-z_0-9"; 423 424foreach my $line (@config_file) { 425 $_ = $line; 426 427 if (/(CONFIG_[$valid]*)=(m|y)/) { 428 $orig_configs{$1} = $2; 429 } 430} 431 432my $repeat = 1; 433 434my $depconfig; 435 436# 437# Note, we do not care about operands (like: &&, ||, !) we want to add any 438# config that is in the depend list of another config. This script does 439# not enable configs that are not already enabled. If we come across a 440# config A that depends on !B, we can still add B to the list of depends 441# to keep on. If A was on in the original config, B would not have been 442# and B would not be turned on by this script. 443# 444sub parse_config_depends 445{ 446 my ($p) = @_; 447 448 while ($p =~ /[$valid]/) { 449 450 if ($p =~ /^[^$valid]*([$valid]+)/) { 451 my $conf = "CONFIG_" . $1; 452 453 $p =~ s/^[^$valid]*[$valid]+//; 454 455 # We only need to process if the depend config is a module 456 if (!defined($orig_configs{$conf}) || $orig_configs{$conf} eq "y") { 457 next; 458 } 459 460 if (!defined($configs{$conf})) { 461 # We must make sure that this config has its 462 # dependencies met. 463 $repeat = 1; # do again 464 dprint "$conf selected by depend $depconfig\n"; 465 $configs{$conf} = 1; 466 } 467 } else { 468 die "this should never happen"; 469 } 470 } 471} 472 473# 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. 478# 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. 483sub parse_config_selects 484{ 485 my ($config, $p) = @_; 486 487 my $next_config; 488 489 while ($p =~ /[$valid]/) { 490 491 if ($p =~ /^[^$valid]*([$valid]+)/) { 492 my $conf = "CONFIG_" . $1; 493 494 $p =~ s/^[^$valid]*[$valid]+//; 495 496 # Make sure that this config exists in the current .config file 497 if (!defined($orig_configs{$conf})) { 498 dprint "$conf not set for $config select\n"; 499 next; 500 } 501 502 # Check if something other than a module selects this config 503 if (defined($orig_configs{$conf}) && $orig_configs{$conf} ne "m") { 504 dprint "$conf (non module) selects config, we are good\n"; 505 # we are good with this 506 return; 507 } 508 if (defined($configs{$conf})) { 509 dprint "$conf selects $config so we are good\n"; 510 # A set config selects this config, we are good 511 return; 512 } 513 # Set this config to be selected 514 if (!defined($next_config)) { 515 $next_config = $conf; 516 } 517 } else { 518 die "this should never happen"; 519 } 520 } 521 522 # If no possible config selected this, then something happened. 523 if (!defined($next_config)) { 524 print STDERR "WARNING: $config is required, but nothing in the\n"; 525 print STDERR " current config selects it.\n"; 526 return; 527 } 528 529 # If we are here, then we found no config that is set and 530 # selects this config. Repeat. 531 $repeat = 1; 532 # Make this config need to be selected 533 $configs{$next_config} = 1; 534 dprint "$next_config selected by select $config\n"; 535} 536 537my %process_selects; 538 539# loop through all configs, select their dependencies. 540sub loop_depend { 541 $repeat = 1; 542 543 while ($repeat) { 544 $repeat = 0; 545 546 forloop: 547 foreach my $config (keys %configs) { 548 549 # If this config is not a module, we do not need to process it 550 if (defined($orig_configs{$config}) && $orig_configs{$config} ne "m") { 551 next forloop; 552 } 553 554 $config =~ s/^CONFIG_//; 555 $depconfig = $config; 556 557 if (defined($depends{$config})) { 558 # This config has dependencies. Make sure they are also included 559 parse_config_depends $depends{$config}; 560 } 561 562 # 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; 566 } 567 } 568 } 569} 570 571sub loop_select { 572 573 foreach my $config (keys %process_selects) { 574 $config =~ s/^CONFIG_//; 575 576 dprint "Process select $config\n"; 577 578 # config has no prompt and must be selected. 579 parse_config_selects $config, $selects{$config}; 580 } 581} 582 583while ($repeat) { 584 # Get the first set of configs and their dependencies. 585 loop_depend; 586 587 $repeat = 0; 588 589 # Now we need to see if we have to check selects; 590 loop_select; 591} 592 593my %setconfigs; 594 595# Finally, read the .config file and turn off any module enabled that 596# we could not find a reason to keep enabled. 597foreach my $line (@config_file) { 598 $_ = $line; 599 600 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"; 606 } else { 607 print; 608 } 609 next; 610 } 611 612 if (/CONFIG_MODULE_SIG_KEY="(.+)"/) { 613 my $orig_cert = $1; 614 my $default_cert = "certs/signing_key.pem"; 615 616 # Check that the logic in this script still matches the one in Kconfig 617 if (!defined($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"; 621 print; 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"; 627 } else { 628 print; 629 } 630 next; 631 } 632 633 if (/CONFIG_SYSTEM_TRUSTED_KEYS="(.+)"/) { 634 my $orig_keys = $1; 635 636 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"; 640 } else { 641 print; 642 } 643 next; 644 } 645 646 if (/^(CONFIG.*)=(m|y)/) { 647 if (defined($configs{$1})) { 648 if ($localyesconfig) { 649 $setconfigs{$1} = 'y'; 650 print "$1=y\n"; 651 next; 652 } else { 653 $setconfigs{$1} = $2; 654 } 655 } elsif ($2 eq "m") { 656 print "# $1 is not set\n"; 657 next; 658 } 659 } 660 print; 661} 662 663# Integrity check, make sure all modules that we want enabled do 664# indeed have their configs set. 665loop: 666foreach my $module (keys(%modules)) { 667 if (defined($objects{$module})) { 668 my @arr = @{$objects{$module}}; 669 foreach my $conf (@arr) { 670 if (defined($setconfigs{$conf})) { 671 next loop; 672 } 673 } 674 print STDERR "module $module did not have configs"; 675 foreach my $conf (@arr) { 676 print STDERR " " , $conf; 677 } 678 print STDERR "\n"; 679 } 680} 681