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} .= " " . $1;
222	} elsif ($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