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 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} .= " " . $1; 222 223 # Get the configs that select this config 224 } elsif ($state ne "NONE" && /^\s*select\s+(\S+)/) { 225 my $conf = $1; 226 if (defined($selects{$conf})) { 227 $selects{$conf} .= " " . $config; 228 } else { 229 $selects{$conf} = $config; 230 } 231 232 # configs without prompts must be selected 233 } elsif ($state ne "NONE" && /^\s*tristate\s\S/) { 234 # note if the config has a prompt 235 $prompts{$config} = 1; 236 237 # Check for if statements 238 } elsif (/^if\s+(.*\S)\s*$/) { 239 my $deps = $1; 240 # remove beginning and ending non text 241 $deps =~ s/^[^a-zA-Z0-9_]*//; 242 $deps =~ s/[^a-zA-Z0-9_]*$//; 243 244 my @deps = split /[^a-zA-Z0-9_]+/, $deps; 245 246 $ifdeps[$iflevel++] = join ':', @deps; 247 248 } elsif (/^endif/) { 249 250 $iflevel-- if ($iflevel); 251 252 # stop on "help" 253 } elsif (/^\s*help\s*$/) { 254 $state = "NONE"; 255 } 256 } 257 close($kinfile); 258} 259 260if ($kconfig) { 261 read_kconfig($kconfig); 262} 263 264# Makefiles can use variables to define their dependencies 265sub convert_vars { 266 my ($line, %vars) = @_; 267 268 my $process = ""; 269 270 while ($line =~ s/^(.*?)(\$\((.*?)\))//) { 271 my $start = $1; 272 my $variable = $2; 273 my $var = $3; 274 275 if (defined($vars{$var})) { 276 $process .= $start . $vars{$var}; 277 } else { 278 $process .= $start . $variable; 279 } 280 } 281 282 $process .= $line; 283 284 return $process; 285} 286 287# Read all Makefiles to map the configs to the objects 288foreach my $makefile (@makefiles) { 289 290 my $line = ""; 291 my %make_vars; 292 293 open(my $infile, '<', $makefile) || die "Can't open $makefile"; 294 while (<$infile>) { 295 # if this line ends with a backslash, continue 296 chomp; 297 if (/^(.*)\\$/) { 298 $line .= $1; 299 next; 300 } 301 302 $line .= $_; 303 $_ = $line; 304 $line = ""; 305 306 my $objs; 307 308 # Convert variables in a line (could define configs) 309 $_ = convert_vars($_, %make_vars); 310 311 # collect objects after obj-$(CONFIG_FOO_BAR) 312 if (/obj-\$\((CONFIG_[^\)]*)\)\s*[+:]?=\s*(.*)/) { 313 $var = $1; 314 $objs = $2; 315 316 # check if variables are set 317 } elsif (/^\s*(\S+)\s*[:]?=\s*(.*\S)/) { 318 $make_vars{$1} = $2; 319 } 320 if (defined($objs)) { 321 foreach my $obj (split /\s+/,$objs) { 322 $obj =~ s/-/_/g; 323 if ($obj =~ /(.*)\.o$/) { 324 # Objects may be enabled by more than one config. 325 # Store configs in an array. 326 my @arr; 327 328 if (defined($objects{$1})) { 329 @arr = @{$objects{$1}}; 330 } 331 332 $arr[$#arr+1] = $var; 333 334 # The objects have a hash mapping to a reference 335 # of an array of configs. 336 $objects{$1} = \@arr; 337 } 338 } 339 } 340 } 341 close($infile); 342} 343 344my %modules; 345my $linfile; 346 347if (defined($lsmod_file)) { 348 if ( ! -f $lsmod_file) { 349 if ( -f $ENV{'objtree'}."/".$lsmod_file) { 350 $lsmod_file = $ENV{'objtree'}."/".$lsmod_file; 351 } else { 352 die "$lsmod_file not found"; 353 } 354 } 355 356 my $otype = ( -x $lsmod_file) ? '-|' : '<'; 357 open($linfile, $otype, $lsmod_file); 358 359} else { 360 361 # see what modules are loaded on this system 362 my $lsmod; 363 364 foreach my $dir ( ("/sbin", "/bin", "/usr/sbin", "/usr/bin") ) { 365 if ( -x "$dir/lsmod" ) { 366 $lsmod = "$dir/lsmod"; 367 last; 368 } 369} 370 if (!defined($lsmod)) { 371 # try just the path 372 $lsmod = "lsmod"; 373 } 374 375 open($linfile, '-|', $lsmod) || die "Can not call lsmod with $lsmod"; 376} 377 378while (<$linfile>) { 379 next if (/^Module/); # Skip the first line. 380 if (/^(\S+)/) { 381 $modules{$1} = 1; 382 } 383} 384close ($linfile); 385 386# add to the configs hash all configs that are needed to enable 387# a loaded module. This is a direct obj-${CONFIG_FOO} += bar.o 388# where we know we need bar.o so we add FOO to the list. 389my %configs; 390foreach my $module (keys(%modules)) { 391 if (defined($objects{$module})) { 392 my @arr = @{$objects{$module}}; 393 foreach my $conf (@arr) { 394 $configs{$conf} = $module; 395 dprint "$conf added by direct ($module)\n"; 396 if ($debugprint) { 397 my $c=$conf; 398 $c =~ s/^CONFIG_//; 399 if (defined($depends{$c})) { 400 dprint " deps = $depends{$c}\n"; 401 } else { 402 dprint " no deps\n"; 403 } 404 } 405 } 406 } else { 407 # Most likely, someone has a custom (binary?) module loaded. 408 print STDERR "$module config not found!!\n"; 409 } 410} 411 412# Read the current config, and see what is enabled. We want to 413# ignore configs that we would not enable anyway. 414 415my %orig_configs; 416my $valid = "A-Za-z_0-9"; 417 418foreach my $line (@config_file) { 419 $_ = $line; 420 421 if (/(CONFIG_[$valid]*)=(m|y)/) { 422 $orig_configs{$1} = $2; 423 } 424} 425 426my $repeat = 1; 427 428my $depconfig; 429 430# 431# Note, we do not care about operands (like: &&, ||, !) we want to add any 432# config that is in the depend list of another config. This script does 433# not enable configs that are not already enabled. If we come across a 434# config A that depends on !B, we can still add B to the list of depends 435# to keep on. If A was on in the original config, B would not have been 436# and B would not be turned on by this script. 437# 438sub parse_config_depends 439{ 440 my ($p) = @_; 441 442 while ($p =~ /[$valid]/) { 443 444 if ($p =~ /^[^$valid]*([$valid]+)/) { 445 my $conf = "CONFIG_" . $1; 446 447 $p =~ s/^[^$valid]*[$valid]+//; 448 449 # We only need to process if the depend config is a module 450 if (!defined($orig_configs{$conf}) || !$orig_configs{conf} eq "m") { 451 next; 452 } 453 454 if (!defined($configs{$conf})) { 455 # We must make sure that this config has its 456 # dependencies met. 457 $repeat = 1; # do again 458 dprint "$conf selected by depend $depconfig\n"; 459 $configs{$conf} = 1; 460 } 461 } else { 462 die "this should never happen"; 463 } 464 } 465} 466 467# Select is treated a bit differently than depends. We call this 468# when a config has no prompt and requires another config to be 469# selected. We use to just select all configs that selected this 470# config, but found that that can balloon into enabling hundreds 471# of configs that we do not care about. 472# 473# The idea is we look at all the configs that select it. If one 474# is already in our list of configs to enable, then there's nothing 475# else to do. If there isn't, we pick the first config that was 476# enabled in the orignal config and use that. 477sub parse_config_selects 478{ 479 my ($config, $p) = @_; 480 481 my $next_config; 482 483 while ($p =~ /[$valid]/) { 484 485 if ($p =~ /^[^$valid]*([$valid]+)/) { 486 my $conf = "CONFIG_" . $1; 487 488 $p =~ s/^[^$valid]*[$valid]+//; 489 490 # Make sure that this config exists in the current .config file 491 if (!defined($orig_configs{$conf})) { 492 dprint "$conf not set for $config select\n"; 493 next; 494 } 495 496 # Check if something other than a module selects this config 497 if (defined($orig_configs{$conf}) && $orig_configs{$conf} ne "m") { 498 dprint "$conf (non module) selects config, we are good\n"; 499 # we are good with this 500 return; 501 } 502 if (defined($configs{$conf})) { 503 dprint "$conf selects $config so we are good\n"; 504 # A set config selects this config, we are good 505 return; 506 } 507 # Set this config to be selected 508 if (!defined($next_config)) { 509 $next_config = $conf; 510 } 511 } else { 512 die "this should never happen"; 513 } 514 } 515 516 # If no possible config selected this, then something happened. 517 if (!defined($next_config)) { 518 print STDERR "WARNING: $config is required, but nothing in the\n"; 519 print STDERR " current config selects it.\n"; 520 return; 521 } 522 523 # If we are here, then we found no config that is set and 524 # selects this config. Repeat. 525 $repeat = 1; 526 # Make this config need to be selected 527 $configs{$next_config} = 1; 528 dprint "$next_config selected by select $config\n"; 529} 530 531my %process_selects; 532 533# loop through all configs, select their dependencies. 534sub loop_depend { 535 $repeat = 1; 536 537 while ($repeat) { 538 $repeat = 0; 539 540 forloop: 541 foreach my $config (keys %configs) { 542 543 # If this config is not a module, we do not need to process it 544 if (defined($orig_configs{$config}) && $orig_configs{$config} ne "m") { 545 next forloop; 546 } 547 548 $config =~ s/^CONFIG_//; 549 $depconfig = $config; 550 551 if (defined($depends{$config})) { 552 # This config has dependencies. Make sure they are also included 553 parse_config_depends $depends{$config}; 554 } 555 556 # If the config has no prompt, then we need to check if a config 557 # that is enabled selected it. Or if we need to enable one. 558 if (!defined($prompts{$config}) && defined($selects{$config})) { 559 $process_selects{$config} = 1; 560 } 561 } 562 } 563} 564 565sub loop_select { 566 567 foreach my $config (keys %process_selects) { 568 $config =~ s/^CONFIG_//; 569 570 dprint "Process select $config\n"; 571 572 # config has no prompt and must be selected. 573 parse_config_selects $config, $selects{$config}; 574 } 575} 576 577while ($repeat) { 578 # Get the first set of configs and their dependencies. 579 loop_depend; 580 581 $repeat = 0; 582 583 # Now we need to see if we have to check selects; 584 loop_select; 585} 586 587my %setconfigs; 588 589# Finally, read the .config file and turn off any module enabled that 590# we could not find a reason to keep enabled. 591foreach my $line (@config_file) { 592 $_ = $line; 593 594 if (/CONFIG_IKCONFIG/) { 595 if (/# CONFIG_IKCONFIG is not set/) { 596 # enable IKCONFIG at least as a module 597 print "CONFIG_IKCONFIG=m\n"; 598 # don't ask about PROC 599 print "# CONFIG_IKCONFIG_PROC is not set\n"; 600 } else { 601 print; 602 } 603 next; 604 } 605 606 if (/^(CONFIG.*)=(m|y)/) { 607 if (defined($configs{$1})) { 608 if ($localyesconfig) { 609 $setconfigs{$1} = 'y'; 610 print "$1=y\n"; 611 next; 612 } else { 613 $setconfigs{$1} = $2; 614 } 615 } elsif ($2 eq "m") { 616 print "# $1 is not set\n"; 617 next; 618 } 619 } 620 print; 621} 622 623# Integrity check, make sure all modules that we want enabled do 624# indeed have their configs set. 625loop: 626foreach my $module (keys(%modules)) { 627 if (defined($objects{$module})) { 628 my @arr = @{$objects{$module}}; 629 foreach my $conf (@arr) { 630 if (defined($setconfigs{$conf})) { 631 next loop; 632 } 633 } 634 print STDERR "module $module did not have configs"; 635 foreach my $conf (@arr) { 636 print STDERR " " , $conf; 637 } 638 print STDERR "\n"; 639 } 640} 641