1#!/usr/bin/perl -w 2# 3# Copywrite 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# 45my $config = ".config"; 46 47my $uname = `uname -r`; 48chomp $uname; 49 50my @searchconfigs = ( 51 { 52 "file" => ".config", 53 "exec" => "cat", 54 }, 55 { 56 "file" => "/proc/config.gz", 57 "exec" => "zcat", 58 }, 59 { 60 "file" => "/boot/config-$uname", 61 "exec" => "cat", 62 }, 63 { 64 "file" => "/boot/vmlinuz-$uname", 65 "exec" => "scripts/extract-ikconfig", 66 "test" => "scripts/extract-ikconfig", 67 }, 68 { 69 "file" => "vmlinux", 70 "exec" => "scripts/extract-ikconfig", 71 "test" => "scripts/extract-ikconfig", 72 }, 73 { 74 "file" => "/lib/modules/$uname/kernel/kernel/configs.ko", 75 "exec" => "scripts/extract-ikconfig", 76 "test" => "scripts/extract-ikconfig", 77 }, 78 { 79 "file" => "kernel/configs.ko", 80 "exec" => "scripts/extract-ikconfig", 81 "test" => "scripts/extract-ikconfig", 82 }, 83 { 84 "file" => "kernel/configs.o", 85 "exec" => "scripts/extract-ikconfig", 86 "test" => "scripts/extract-ikconfig", 87 }, 88); 89 90sub find_config { 91 foreach my $conf (@searchconfigs) { 92 my $file = $conf->{"file"}; 93 94 next if ( ! -f "$file"); 95 96 if (defined($conf->{"test"})) { 97 `$conf->{"test"} $conf->{"file"} 2>/dev/null`; 98 next if ($?); 99 } 100 101 my $exec = $conf->{"exec"}; 102 103 print STDERR "using config: '$file'\n"; 104 105 open(CIN, "$exec $file |") || die "Failed to run $exec $file"; 106 return; 107 } 108 die "No config file found"; 109} 110 111find_config; 112 113# Get the build source and top level Kconfig file (passed in) 114my $ksource = $ARGV[0]; 115my $kconfig = $ARGV[1]; 116 117my @makefiles = `find $ksource -name Makefile`; 118my %depends; 119my %selects; 120my %prompts; 121my %objects; 122my $var; 123my $cont = 0; 124 125# prevent recursion 126my %read_kconfigs; 127 128sub read_kconfig { 129 my ($kconfig) = @_; 130 131 my $state = "NONE"; 132 my $config; 133 my @kconfigs; 134 135 open(KIN, "$ksource/$kconfig") || die "Can't open $kconfig"; 136 while (<KIN>) { 137 chomp; 138 139 # collect any Kconfig sources 140 if (/^source\s*"(.*)"/) { 141 $kconfigs[$#kconfigs+1] = $1; 142 } 143 144 # configs found 145 if (/^\s*config\s+(\S+)\s*$/) { 146 $state = "NEW"; 147 $config = $1; 148 149 # collect the depends for the config 150 } elsif ($state eq "NEW" && /^\s*depends\s+on\s+(.*)$/) { 151 $state = "DEP"; 152 $depends{$config} = $1; 153 } elsif ($state eq "DEP" && /^\s*depends\s+on\s+(.*)$/) { 154 $depends{$config} .= " " . $1; 155 156 # Get the configs that select this config 157 } elsif ($state ne "NONE" && /^\s*select\s+(\S+)/) { 158 if (defined($selects{$1})) { 159 $selects{$1} .= " " . $config; 160 } else { 161 $selects{$1} = $config; 162 } 163 164 # configs without prompts must be selected 165 } elsif ($state ne "NONE" && /^\s*tristate\s\S/) { 166 # note if the config has a prompt 167 $prompt{$config} = 1; 168 169 # stop on "help" 170 } elsif (/^\s*help\s*$/) { 171 $state = "NONE"; 172 } 173 } 174 close(KIN); 175 176 # read in any configs that were found. 177 foreach $kconfig (@kconfigs) { 178 if (!defined($read_kconfigs{$kconfig})) { 179 $read_kconfigs{$kconfig} = 1; 180 read_kconfig($kconfig); 181 } 182 } 183} 184 185if ($kconfig) { 186 read_kconfig($kconfig); 187} 188 189# Read all Makefiles to map the configs to the objects 190foreach my $makefile (@makefiles) { 191 chomp $makefile; 192 193 open(MIN,$makefile) || die "Can't open $makefile"; 194 while (<MIN>) { 195 my $objs; 196 197 # is this a line after a line with a backslash? 198 if ($cont && /(\S.*)$/) { 199 $objs = $1; 200 } 201 $cont = 0; 202 203 # collect objects after obj-$(CONFIG_FOO_BAR) 204 if (/obj-\$\((CONFIG_[^\)]*)\)\s*[+:]?=\s*(.*)/) { 205 $var = $1; 206 $objs = $2; 207 } 208 if (defined($objs)) { 209 # test if the line ends with a backslash 210 if ($objs =~ m,(.*)\\$,) { 211 $objs = $1; 212 $cont = 1; 213 } 214 215 foreach my $obj (split /\s+/,$objs) { 216 $obj =~ s/-/_/g; 217 if ($obj =~ /(.*)\.o$/) { 218 # Objects may bes enabled by more than one config. 219 # Store configs in an array. 220 my @arr; 221 222 if (defined($objects{$1})) { 223 @arr = @{$objects{$1}}; 224 } 225 226 $arr[$#arr+1] = $var; 227 228 # The objects have a hash mapping to a reference 229 # of an array of configs. 230 $objects{$1} = \@arr; 231 } 232 } 233 } 234 } 235 close(MIN); 236} 237 238my %modules; 239 240# see what modules are loaded on this system 241open(LIN,"/sbin/lsmod|") || die "Cant lsmod"; 242while (<LIN>) { 243 next if (/^Module/); # Skip the first line. 244 if (/^(\S+)/) { 245 $modules{$1} = 1; 246 } 247} 248close (LIN); 249 250# add to the configs hash all configs that are needed to enable 251# a loaded module. 252my %configs; 253foreach my $module (keys(%modules)) { 254 if (defined($objects{$module})) { 255 @arr = @{$objects{$module}}; 256 foreach my $conf (@arr) { 257 $configs{$conf} = $module; 258 } 259 } else { 260 # Most likely, someone has a custom (binary?) module loaded. 261 print STDERR "$module config not found!!\n"; 262 } 263} 264 265my $valid = "A-Za-z_0-9"; 266my $repeat = 1; 267 268# 269# Note, we do not care about operands (like: &&, ||, !) we want to add any 270# config that is in the depend list of another config. This script does 271# not enable configs that are not already enabled. If we come across a 272# config A that depends on !B, we can still add B to the list of depends 273# to keep on. If A was on in the original config, B would not have been 274# and B would not be turned on by this script. 275# 276sub parse_config_dep_select 277{ 278 my ($p) = @_; 279 280 while ($p =~ /[$valid]/) { 281 282 if ($p =~ /^[^$valid]*([$valid]+)/) { 283 my $conf = "CONFIG_" . $1; 284 285 $p =~ s/^[^$valid]*[$valid]+//; 286 287 if (!defined($configs{$conf})) { 288 # We must make sure that this config has its 289 # dependencies met. 290 $repeat = 1; # do again 291 $configs{$conf} = 1; 292 } 293 } else { 294 die "this should never happen"; 295 } 296 } 297} 298 299while ($repeat) { 300 $repeat = 0; 301 302 foreach my $config (keys %configs) { 303 $config =~ s/^CONFIG_//; 304 305 if (defined($depends{$config})) { 306 # This config has dependencies. Make sure they are also included 307 parse_config_dep_select $depends{$config}; 308 } 309 310 if (defined($prompt{$config}) || !defined($selects{$config})) { 311 next; 312 } 313 314 # config has no prompt and must be selected. 315 parse_config_dep_select $selects{$config}; 316 } 317} 318 319my %setconfigs; 320 321# Finally, read the .config file and turn off any module enabled that 322# we could not find a reason to keep enabled. 323while(<CIN>) { 324 325 if (/CONFIG_IKCONFIG/) { 326 if (/# CONFIG_IKCONFIG is not set/) { 327 # enable IKCONFIG at least as a module 328 print "CONFIG_IKCONFIG=m\n"; 329 # don't ask about PROC 330 print "# CONFIG_IKCONFIG_PROC is not set\n"; 331 } else { 332 print; 333 } 334 next; 335 } 336 337 if (/^(CONFIG.*)=(m|y)/) { 338 if (defined($configs{$1})) { 339 $setconfigs{$1} = $2; 340 } elsif ($2 eq "m") { 341 print "# $1 is not set\n"; 342 next; 343 } 344 } 345 print; 346} 347close(CIN); 348 349# Integrity check, make sure all modules that we want enabled do 350# indeed have their configs set. 351loop: 352foreach my $module (keys(%modules)) { 353 if (defined($objects{$module})) { 354 my @arr = @{$objects{$module}}; 355 foreach my $conf (@arr) { 356 if (defined($setconfigs{$conf})) { 357 next loop; 358 } 359 } 360 print STDERR "module $module did not have configs"; 361 foreach my $conf (@arr) { 362 print STDERR " " , $conf; 363 } 364 print STDERR "\n"; 365 } 366} 367