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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