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    my @kconfigs;
160
161    my $cont = 0;
162    my $line;
163
164    my $source = "$ksource/$kconfig";
165    my $last_source = "";
166
167    # Check for any environment variables used
168    while ($source =~ /\$(\w+)/ && $last_source ne $source) {
169	my $env = $1;
170	$last_source = $source;
171	$source =~ s/\$$env/$ENV{$env}/;
172    }
173
174    open(my $kinfile, '<', $source) || die "Can't open $kconfig";
175    while (<$kinfile>) {
176	chomp;
177
178	# Make sure that lines ending with \ continue
179	if ($cont) {
180	    $_ = $line . " " . $_;
181	}
182
183	if (s/\\$//) {
184	    $cont = 1;
185	    $line = $_;
186	    next;
187	}
188
189	$cont = 0;
190
191	# collect any Kconfig sources
192	if (/^source\s*"(.*)"/) {
193	    $kconfigs[$#kconfigs+1] = $1;
194	}
195
196	# configs found
197	if (/^\s*(menu)?config\s+(\S+)\s*$/) {
198	    $state = "NEW";
199	    $config = $2;
200
201	    # Add depends for 'if' nesting
202	    for (my $i = 0; $i < $iflevel; $i++) {
203		if ($i) {
204		    $depends{$config} .= " " . $ifdeps[$i];
205		} else {
206		    $depends{$config} = $ifdeps[$i];
207		}
208		$state = "DEP";
209	    }
210
211	# collect the depends for the config
212	} elsif ($state eq "NEW" && /^\s*depends\s+on\s+(.*)$/) {
213	    $state = "DEP";
214	    $depends{$config} = $1;
215	} elsif ($state eq "DEP" && /^\s*depends\s+on\s+(.*)$/) {
216	    $depends{$config} .= " " . $1;
217
218	# Get the configs that select this config
219	} elsif ($state ne "NONE" && /^\s*select\s+(\S+)/) {
220	    my $conf = $1;
221	    if (defined($selects{$conf})) {
222		$selects{$conf} .= " " . $config;
223	    } else {
224		$selects{$conf} = $config;
225	    }
226
227	# configs without prompts must be selected
228	} elsif ($state ne "NONE" && /^\s*tristate\s\S/) {
229	    # note if the config has a prompt
230	    $prompts{$config} = 1;
231
232	# Check for if statements
233	} elsif (/^if\s+(.*\S)\s*$/) {
234	    my $deps = $1;
235	    # remove beginning and ending non text
236	    $deps =~ s/^[^a-zA-Z0-9_]*//;
237	    $deps =~ s/[^a-zA-Z0-9_]*$//;
238
239	    my @deps = split /[^a-zA-Z0-9_]+/, $deps;
240
241	    $ifdeps[$iflevel++] = join ':', @deps;
242
243	} elsif (/^endif/) {
244
245	    $iflevel-- if ($iflevel);
246
247	# stop on "help"
248	} elsif (/^\s*help\s*$/) {
249	    $state = "NONE";
250	}
251    }
252    close($kinfile);
253
254    # read in any configs that were found.
255    foreach my $kconfig (@kconfigs) {
256	if (!defined($read_kconfigs{$kconfig})) {
257	    $read_kconfigs{$kconfig} = 1;
258	    read_kconfig($kconfig);
259	}
260    }
261}
262
263if ($kconfig) {
264    read_kconfig($kconfig);
265}
266
267# Makefiles can use variables to define their dependencies
268sub convert_vars {
269    my ($line, %vars) = @_;
270
271    my $process = "";
272
273    while ($line =~ s/^(.*?)(\$\((.*?)\))//) {
274	my $start = $1;
275	my $variable = $2;
276	my $var = $3;
277
278	if (defined($vars{$var})) {
279	    $process .= $start . $vars{$var};
280	} else {
281	    $process .= $start . $variable;
282	}
283    }
284
285    $process .= $line;
286
287    return $process;
288}
289
290# Read all Makefiles to map the configs to the objects
291foreach my $makefile (@makefiles) {
292
293    my $line = "";
294    my %make_vars;
295
296    open(my $infile, '<', $makefile) || die "Can't open $makefile";
297    while (<$infile>) {
298	# if this line ends with a backslash, continue
299	chomp;
300	if (/^(.*)\\$/) {
301	    $line .= $1;
302	    next;
303	}
304
305	$line .= $_;
306	$_ = $line;
307	$line = "";
308
309	my $objs;
310
311	# Convert variables in a line (could define configs)
312	$_ = convert_vars($_, %make_vars);
313
314	# collect objects after obj-$(CONFIG_FOO_BAR)
315	if (/obj-\$\((CONFIG_[^\)]*)\)\s*[+:]?=\s*(.*)/) {
316	    $var = $1;
317	    $objs = $2;
318
319	# check if variables are set
320	} elsif (/^\s*(\S+)\s*[:]?=\s*(.*\S)/) {
321	    $make_vars{$1} = $2;
322	}
323	if (defined($objs)) {
324	    foreach my $obj (split /\s+/,$objs) {
325		$obj =~ s/-/_/g;
326		if ($obj =~ /(.*)\.o$/) {
327		    # Objects may be enabled by more than one config.
328		    # Store configs in an array.
329		    my @arr;
330
331		    if (defined($objects{$1})) {
332			@arr = @{$objects{$1}};
333		    }
334
335		    $arr[$#arr+1] = $var;
336
337		    # The objects have a hash mapping to a reference
338		    # of an array of configs.
339		    $objects{$1} = \@arr;
340		}
341	    }
342	}
343    }
344    close($infile);
345}
346
347my %modules;
348my $linfile;
349
350if (defined($lsmod_file)) {
351    if ( ! -f $lsmod_file) {
352	if ( -f $ENV{'objtree'}."/".$lsmod_file) {
353	    $lsmod_file = $ENV{'objtree'}."/".$lsmod_file;
354	} else {
355		die "$lsmod_file not found";
356	}
357    }
358
359    my $otype = ( -x $lsmod_file) ? '-|' : '<';
360    open($linfile, $otype, $lsmod_file);
361
362} else {
363
364    # see what modules are loaded on this system
365    my $lsmod;
366
367    foreach my $dir ( ("/sbin", "/bin", "/usr/sbin", "/usr/bin") ) {
368	if ( -x "$dir/lsmod" ) {
369	    $lsmod = "$dir/lsmod";
370	    last;
371	}
372}
373    if (!defined($lsmod)) {
374	# try just the path
375	$lsmod = "lsmod";
376    }
377
378    open($linfile, '-|', $lsmod) || die "Can not call lsmod with $lsmod";
379}
380
381while (<$linfile>) {
382	next if (/^Module/);  # Skip the first line.
383	if (/^(\S+)/) {
384		$modules{$1} = 1;
385	}
386}
387close ($linfile);
388
389# add to the configs hash all configs that are needed to enable
390# a loaded module. This is a direct obj-${CONFIG_FOO} += bar.o
391# where we know we need bar.o so we add FOO to the list.
392my %configs;
393foreach my $module (keys(%modules)) {
394    if (defined($objects{$module})) {
395	my @arr = @{$objects{$module}};
396	foreach my $conf (@arr) {
397	    $configs{$conf} = $module;
398	    dprint "$conf added by direct ($module)\n";
399	}
400    } else {
401	# Most likely, someone has a custom (binary?) module loaded.
402	print STDERR "$module config not found!!\n";
403    }
404}
405
406# Read the current config, and see what is enabled. We want to
407# ignore configs that we would not enable anyway.
408
409my %orig_configs;
410my $valid = "A-Za-z_0-9";
411
412foreach my $line (@config_file) {
413    $_ = $line;
414
415    if (/(CONFIG_[$valid]*)=(m|y)/) {
416	$orig_configs{$1} = $2;
417    }
418}
419
420my $repeat = 1;
421
422my $depconfig;
423
424#
425# Note, we do not care about operands (like: &&, ||, !) we want to add any
426# config that is in the depend list of another config. This script does
427# not enable configs that are not already enabled. If we come across a
428# config A that depends on !B, we can still add B to the list of depends
429# to keep on. If A was on in the original config, B would not have been
430# and B would not be turned on by this script.
431#
432sub parse_config_depends
433{
434    my ($p) = @_;
435
436    while ($p =~ /[$valid]/) {
437
438	if ($p =~ /^[^$valid]*([$valid]+)/) {
439	    my $conf = "CONFIG_" . $1;
440
441	    $p =~ s/^[^$valid]*[$valid]+//;
442
443	    # We only need to process if the depend config is a module
444	    if (!defined($orig_configs{$conf}) || !$orig_configs{conf} eq "m") {
445		next;
446	    }
447
448	    if (!defined($configs{$conf})) {
449		# We must make sure that this config has its
450		# dependencies met.
451		$repeat = 1; # do again
452		dprint "$conf selected by depend $depconfig\n";
453		$configs{$conf} = 1;
454	    }
455	} else {
456	    die "this should never happen";
457	}
458    }
459}
460
461# Select is treated a bit differently than depends. We call this
462# when a config has no prompt and requires another config to be
463# selected. We use to just select all configs that selected this
464# config, but found that that can balloon into enabling hundreds
465# of configs that we do not care about.
466#
467# The idea is we look at all the configs that select it. If one
468# is already in our list of configs to enable, then there's nothing
469# else to do. If there isn't, we pick the first config that was
470# enabled in the orignal config and use that.
471sub parse_config_selects
472{
473    my ($config, $p) = @_;
474
475    my $next_config;
476
477    while ($p =~ /[$valid]/) {
478
479	if ($p =~ /^[^$valid]*([$valid]+)/) {
480	    my $conf = "CONFIG_" . $1;
481
482	    $p =~ s/^[^$valid]*[$valid]+//;
483
484	    # Make sure that this config exists in the current .config file
485	    if (!defined($orig_configs{$conf})) {
486		dprint "$conf not set for $config select\n";
487		next;
488	    }
489
490	    # Check if something other than a module selects this config
491	    if (defined($orig_configs{$conf}) && $orig_configs{$conf} ne "m") {
492		dprint "$conf (non module) selects config, we are good\n";
493		# we are good with this
494		return;
495	    }
496	    if (defined($configs{$conf})) {
497		dprint "$conf selects $config so we are good\n";
498		# A set config selects this config, we are good
499		return;
500	    }
501	    # Set this config to be selected
502	    if (!defined($next_config)) {
503		$next_config = $conf;
504	    }
505	} else {
506	    die "this should never happen";
507	}
508    }
509
510    # If no possible config selected this, then something happened.
511    if (!defined($next_config)) {
512	print STDERR "WARNING: $config is required, but nothing in the\n";
513	print STDERR "  current config selects it.\n";
514	return;
515    }
516
517    # If we are here, then we found no config that is set and
518    # selects this config. Repeat.
519    $repeat = 1;
520    # Make this config need to be selected
521    $configs{$next_config} = 1;
522    dprint "$next_config selected by select $config\n";
523}
524
525my %process_selects;
526
527# loop through all configs, select their dependencies.
528sub loop_depend {
529    $repeat = 1;
530
531    while ($repeat) {
532	$repeat = 0;
533
534      forloop:
535	foreach my $config (keys %configs) {
536
537	    # If this config is not a module, we do not need to process it
538	    if (defined($orig_configs{$config}) && $orig_configs{$config} ne "m") {
539		next forloop;
540	    }
541
542	    $config =~ s/^CONFIG_//;
543	    $depconfig = $config;
544
545	    if (defined($depends{$config})) {
546		# This config has dependencies. Make sure they are also included
547		parse_config_depends $depends{$config};
548	    }
549
550	    # If the config has no prompt, then we need to check if a config
551	    # that is enabled selected it. Or if we need to enable one.
552	    if (!defined($prompts{$config}) && defined($selects{$config})) {
553		$process_selects{$config} = 1;
554	    }
555	}
556    }
557}
558
559sub loop_select {
560
561    foreach my $config (keys %process_selects) {
562	$config =~ s/^CONFIG_//;
563
564	dprint "Process select $config\n";
565
566	# config has no prompt and must be selected.
567	parse_config_selects $config, $selects{$config};
568    }
569}
570
571while ($repeat) {
572    # Get the first set of configs and their dependencies.
573    loop_depend;
574
575    $repeat = 0;
576
577    # Now we need to see if we have to check selects;
578    loop_select;
579}
580
581my %setconfigs;
582
583# Finally, read the .config file and turn off any module enabled that
584# we could not find a reason to keep enabled.
585foreach my $line (@config_file) {
586    $_ = $line;
587
588    if (/CONFIG_IKCONFIG/) {
589	if (/# CONFIG_IKCONFIG is not set/) {
590	    # enable IKCONFIG at least as a module
591	    print "CONFIG_IKCONFIG=m\n";
592	    # don't ask about PROC
593	    print "# CONFIG_IKCONFIG_PROC is not set\n";
594	} else {
595	    print;
596	}
597	next;
598    }
599
600    if (/^(CONFIG.*)=(m|y)/) {
601	if (defined($configs{$1})) {
602	    if ($localyesconfig) {
603	        $setconfigs{$1} = 'y';
604		print "$1=y\n";
605		next;
606	    } else {
607	        $setconfigs{$1} = $2;
608	    }
609	} elsif ($2 eq "m") {
610	    print "# $1 is not set\n";
611	    next;
612	}
613    }
614    print;
615}
616
617# Integrity check, make sure all modules that we want enabled do
618# indeed have their configs set.
619loop:
620foreach my $module (keys(%modules)) {
621    if (defined($objects{$module})) {
622	my @arr = @{$objects{$module}};
623	foreach my $conf (@arr) {
624	    if (defined($setconfigs{$conf})) {
625		next loop;
626	    }
627	}
628	print STDERR "module $module did not have configs";
629	foreach my $conf (@arr) {
630	    print STDERR " " , $conf;
631	}
632	print STDERR "\n";
633    }
634}
635