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