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 find_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(CIN, "$exec $file |") || die "Failed to run $exec $file";
119	return;
120    }
121    die "No config file found";
122}
123
124find_config;
125
126# Read in the entire config file into config_file
127my @config_file = <CIN>;
128close CIN;
129
130# Parse options
131my $localmodconfig = 0;
132my $localyesconfig = 0;
133
134GetOptions("localmodconfig" => \$localmodconfig,
135	   "localyesconfig" => \$localyesconfig);
136
137# Get the build source and top level Kconfig file (passed in)
138my $ksource = $ARGV[0];
139my $kconfig = $ARGV[1];
140my $lsmod_file = $ENV{'LSMOD'};
141
142my @makefiles = `find $ksource -name Makefile 2>/dev/null`;
143chomp @makefiles;
144
145my %depends;
146my %selects;
147my %prompts;
148my %objects;
149my $var;
150my $iflevel = 0;
151my @ifdeps;
152
153# prevent recursion
154my %read_kconfigs;
155
156sub read_kconfig {
157    my ($kconfig) = @_;
158
159    my $state = "NONE";
160    my $config;
161    my @kconfigs;
162
163    my $cont = 0;
164    my $line;
165
166    my $source = "$ksource/$kconfig";
167    my $last_source = "";
168
169    # Check for any environment variables used
170    while ($source =~ /\$(\w+)/ && $last_source ne $source) {
171	my $env = $1;
172	$last_source = $source;
173	$source =~ s/\$$env/$ENV{$env}/;
174    }
175
176    open(KIN, "$source") || die "Can't open $kconfig";
177    while (<KIN>) {
178	chomp;
179
180	# Make sure that lines ending with \ continue
181	if ($cont) {
182	    $_ = $line . " " . $_;
183	}
184
185	if (s/\\$//) {
186	    $cont = 1;
187	    $line = $_;
188	    next;
189	}
190
191	$cont = 0;
192
193	# collect any Kconfig sources
194	if (/^source\s*"(.*)"/) {
195	    $kconfigs[$#kconfigs+1] = $1;
196	}
197
198	# configs found
199	if (/^\s*(menu)?config\s+(\S+)\s*$/) {
200	    $state = "NEW";
201	    $config = $2;
202
203	    # Add depends for 'if' nesting
204	    for (my $i = 0; $i < $iflevel; $i++) {
205		if ($i) {
206		    $depends{$config} .= " " . $ifdeps[$i];
207		} else {
208		    $depends{$config} = $ifdeps[$i];
209		}
210		$state = "DEP";
211	    }
212
213	# collect the depends for the config
214	} elsif ($state eq "NEW" && /^\s*depends\s+on\s+(.*)$/) {
215	    $state = "DEP";
216	    $depends{$config} = $1;
217	} elsif ($state eq "DEP" && /^\s*depends\s+on\s+(.*)$/) {
218	    $depends{$config} .= " " . $1;
219
220	# Get the configs that select this config
221	} elsif ($state ne "NONE" && /^\s*select\s+(\S+)/) {
222	    my $conf = $1;
223	    if (defined($selects{$conf})) {
224		$selects{$conf} .= " " . $config;
225	    } else {
226		$selects{$conf} = $config;
227	    }
228
229	# configs without prompts must be selected
230	} elsif ($state ne "NONE" && /^\s*tristate\s\S/) {
231	    # note if the config has a prompt
232	    $prompts{$config} = 1;
233
234	# Check for if statements
235	} elsif (/^if\s+(.*\S)\s*$/) {
236	    my $deps = $1;
237	    # remove beginning and ending non text
238	    $deps =~ s/^[^a-zA-Z0-9_]*//;
239	    $deps =~ s/[^a-zA-Z0-9_]*$//;
240
241	    my @deps = split /[^a-zA-Z0-9_]+/, $deps;
242
243	    $ifdeps[$iflevel++] = join ':', @deps;
244
245	} elsif (/^endif/) {
246
247	    $iflevel-- if ($iflevel);
248
249	# stop on "help"
250	} elsif (/^\s*help\s*$/) {
251	    $state = "NONE";
252	}
253    }
254    close(KIN);
255
256    # read in any configs that were found.
257    foreach $kconfig (@kconfigs) {
258	if (!defined($read_kconfigs{$kconfig})) {
259	    $read_kconfigs{$kconfig} = 1;
260	    read_kconfig($kconfig);
261	}
262    }
263}
264
265if ($kconfig) {
266    read_kconfig($kconfig);
267}
268
269# Makefiles can use variables to define their dependencies
270sub convert_vars {
271    my ($line, %vars) = @_;
272
273    my $process = "";
274
275    while ($line =~ s/^(.*?)(\$\((.*?)\))//) {
276	my $start = $1;
277	my $variable = $2;
278	my $var = $3;
279
280	if (defined($vars{$var})) {
281	    $process .= $start . $vars{$var};
282	} else {
283	    $process .= $start . $variable;
284	}
285    }
286
287    $process .= $line;
288
289    return $process;
290}
291
292# Read all Makefiles to map the configs to the objects
293foreach my $makefile (@makefiles) {
294
295    my $line = "";
296    my %make_vars;
297
298    open(MIN,$makefile) || die "Can't open $makefile";
299    while (<MIN>) {
300	# if this line ends with a backslash, continue
301	chomp;
302	if (/^(.*)\\$/) {
303	    $line .= $1;
304	    next;
305	}
306
307	$line .= $_;
308	$_ = $line;
309	$line = "";
310
311	my $objs;
312
313	# Convert variables in a line (could define configs)
314	$_ = convert_vars($_, %make_vars);
315
316	# collect objects after obj-$(CONFIG_FOO_BAR)
317	if (/obj-\$\((CONFIG_[^\)]*)\)\s*[+:]?=\s*(.*)/) {
318	    $var = $1;
319	    $objs = $2;
320
321	# check if variables are set
322	} elsif (/^\s*(\S+)\s*[:]?=\s*(.*\S)/) {
323	    $make_vars{$1} = $2;
324	}
325	if (defined($objs)) {
326	    foreach my $obj (split /\s+/,$objs) {
327		$obj =~ s/-/_/g;
328		if ($obj =~ /(.*)\.o$/) {
329		    # Objects may be enabled by more than one config.
330		    # Store configs in an array.
331		    my @arr;
332
333		    if (defined($objects{$1})) {
334			@arr = @{$objects{$1}};
335		    }
336
337		    $arr[$#arr+1] = $var;
338
339		    # The objects have a hash mapping to a reference
340		    # of an array of configs.
341		    $objects{$1} = \@arr;
342		}
343	    }
344	}
345    }
346    close(MIN);
347}
348
349my %modules;
350
351if (defined($lsmod_file)) {
352    if ( ! -f $lsmod_file) {
353	if ( -f $ENV{'objtree'}."/".$lsmod_file) {
354	    $lsmod_file = $ENV{'objtree'}."/".$lsmod_file;
355	} else {
356		die "$lsmod_file not found";
357	}
358    }
359    if ( -x $lsmod_file) {
360	# the file is executable, run it
361	open(LIN, "$lsmod_file|");
362    } else {
363	# Just read the contents
364	open(LIN, "$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	$lsmod = "lsmod";
380    }
381
382    open(LIN,"$lsmod|") || die "Can not call lsmod with $lsmod";
383}
384
385while (<LIN>) {
386	next if (/^Module/);  # Skip the first line.
387	if (/^(\S+)/) {
388		$modules{$1} = 1;
389	}
390}
391close (LIN);
392
393# add to the configs hash all configs that are needed to enable
394# a loaded module. This is a direct obj-${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 ($module)\n";
403	}
404    } else {
405	# Most likely, someone has a custom (binary?) module loaded.
406	print STDERR "$module config not found!!\n";
407    }
408}
409
410# Read the current config, and see what is enabled. We want to
411# ignore configs that we would not enable anyway.
412
413my %orig_configs;
414my $valid = "A-Za-z_0-9";
415
416foreach my $line (@config_file) {
417    $_ = $line;
418
419    if (/(CONFIG_[$valid]*)=(m|y)/) {
420	$orig_configs{$1} = $2;
421    }
422}
423
424my $repeat = 1;
425
426my $depconfig;
427
428#
429# Note, we do not care about operands (like: &&, ||, !) we want to add any
430# config that is in the depend list of another config. This script does
431# not enable configs that are not already enabled. If we come across a
432# config A that depends on !B, we can still add B to the list of depends
433# to keep on. If A was on in the original config, B would not have been
434# and B would not be turned on by this script.
435#
436sub parse_config_depends
437{
438    my ($p) = @_;
439
440    while ($p =~ /[$valid]/) {
441
442	if ($p =~ /^[^$valid]*([$valid]+)/) {
443	    my $conf = "CONFIG_" . $1;
444
445	    $p =~ s/^[^$valid]*[$valid]+//;
446
447	    # We only need to process if the depend config is a module
448	    if (!defined($orig_configs{$conf}) || !$orig_configs{conf} eq "m") {
449		next;
450	    }
451
452	    if (!defined($configs{$conf})) {
453		# We must make sure that this config has its
454		# dependencies met.
455		$repeat = 1; # do again
456		dprint "$conf selected by depend $depconfig\n";
457		$configs{$conf} = 1;
458	    }
459	} else {
460	    die "this should never happen";
461	}
462    }
463}
464
465# Select is treated a bit differently than depends. We call this
466# when a config has no prompt and requires another config to be
467# selected. We use to just select all configs that selected this
468# config, but found that that can balloon into enabling hundreds
469# of configs that we do not care about.
470#
471# The idea is we look at all the configs that select it. If one
472# is already in our list of configs to enable, then there's nothing
473# else to do. If there isn't, we pick the first config that was
474# enabled in the orignal config and use that.
475sub parse_config_selects
476{
477    my ($config, $p) = @_;
478
479    my $next_config;
480
481    while ($p =~ /[$valid]/) {
482
483	if ($p =~ /^[^$valid]*([$valid]+)/) {
484	    my $conf = "CONFIG_" . $1;
485
486	    $p =~ s/^[^$valid]*[$valid]+//;
487
488	    # Make sure that this config exists in the current .config file
489	    if (!defined($orig_configs{$conf})) {
490		dprint "$conf not set for $config select\n";
491		next;
492	    }
493
494	    # Check if something other than a module selects this config
495	    if (defined($orig_configs{$conf}) && $orig_configs{$conf} ne "m") {
496		dprint "$conf (non module) selects config, we are good\n";
497		# we are good with this
498		return;
499	    }
500	    if (defined($configs{$conf})) {
501		dprint "$conf selects $config so we are good\n";
502		# A set config selects this config, we are good
503		return;
504	    }
505	    # Set this config to be selected
506	    if (!defined($next_config)) {
507		$next_config = $conf;
508	    }
509	} else {
510	    die "this should never happen";
511	}
512    }
513
514    # If no possible config selected this, then something happened.
515    if (!defined($next_config)) {
516	print STDERR "WARNING: $config is required, but nothing in the\n";
517	print STDERR "  current config selects it.\n";
518	return;
519    }
520
521    # If we are here, then we found no config that is set and
522    # selects this config. Repeat.
523    $repeat = 1;
524    # Make this config need to be selected
525    $configs{$next_config} = 1;
526    dprint "$next_config selected by select $config\n";
527}
528
529my %process_selects;
530
531# loop through all configs, select their dependencies.
532sub loop_depend {
533    $repeat = 1;
534
535    while ($repeat) {
536	$repeat = 0;
537
538      forloop:
539	foreach my $config (keys %configs) {
540
541	    # If this config is not a module, we do not need to process it
542	    if (defined($orig_configs{$config}) && $orig_configs{$config} ne "m") {
543		next forloop;
544	    }
545
546	    $config =~ s/^CONFIG_//;
547	    $depconfig = $config;
548
549	    if (defined($depends{$config})) {
550		# This config has dependencies. Make sure they are also included
551		parse_config_depends $depends{$config};
552	    }
553
554	    # If the config has no prompt, then we need to check if a config
555	    # that is enabled selected it. Or if we need to enable one.
556	    if (!defined($prompts{$config}) && defined($selects{$config})) {
557		$process_selects{$config} = 1;
558	    }
559	}
560    }
561}
562
563sub loop_select {
564
565    foreach my $config (keys %process_selects) {
566	$config =~ s/^CONFIG_//;
567
568	dprint "Process select $config\n";
569
570	# config has no prompt and must be selected.
571	parse_config_selects $config, $selects{$config};
572    }
573}
574
575while ($repeat) {
576    # Get the first set of configs and their dependencies.
577    loop_depend;
578
579    $repeat = 0;
580
581    # Now we need to see if we have to check selects;
582    loop_select;
583}
584
585my %setconfigs;
586
587# Finally, read the .config file and turn off any module enabled that
588# we could not find a reason to keep enabled.
589foreach my $line (@config_file) {
590    $_ = $line;
591
592    if (/CONFIG_IKCONFIG/) {
593	if (/# CONFIG_IKCONFIG is not set/) {
594	    # enable IKCONFIG at least as a module
595	    print "CONFIG_IKCONFIG=m\n";
596	    # don't ask about PROC
597	    print "# CONFIG_IKCONFIG_PROC is not set\n";
598	} else {
599	    print;
600	}
601	next;
602    }
603
604    if (/^(CONFIG.*)=(m|y)/) {
605	if (defined($configs{$1})) {
606	    if ($localyesconfig) {
607	        $setconfigs{$1} = 'y';
608	    } else {
609	        $setconfigs{$1} = $2;
610	    }
611	} elsif ($2 eq "m") {
612	    print "# $1 is not set\n";
613	    next;
614	}
615    }
616    print;
617}
618
619# Integrity check, make sure all modules that we want enabled do
620# indeed have their configs set.
621loop:
622foreach my $module (keys(%modules)) {
623    if (defined($objects{$module})) {
624	my @arr = @{$objects{$module}};
625	foreach my $conf (@arr) {
626	    if (defined($setconfigs{$conf})) {
627		next loop;
628	    }
629	}
630	print STDERR "module $module did not have configs";
631	foreach my $conf (@arr) {
632	    print STDERR " " , $conf;
633	}
634	print STDERR "\n";
635    }
636}
637