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;
46
47my $config = ".config";
48
49my $uname = `uname -r`;
50chomp $uname;
51
52my @searchconfigs = (
53	{
54	    "file" => ".config",
55	    "exec" => "cat",
56	},
57	{
58	    "file" => "/proc/config.gz",
59	    "exec" => "zcat",
60	},
61	{
62	    "file" => "/boot/config-$uname",
63	    "exec" => "cat",
64	},
65	{
66	    "file" => "/boot/vmlinuz-$uname",
67	    "exec" => "scripts/extract-ikconfig",
68	    "test" => "scripts/extract-ikconfig",
69	},
70	{
71	    "file" => "vmlinux",
72	    "exec" => "scripts/extract-ikconfig",
73	    "test" => "scripts/extract-ikconfig",
74	},
75	{
76	    "file" => "/lib/modules/$uname/kernel/kernel/configs.ko",
77	    "exec" => "scripts/extract-ikconfig",
78	    "test" => "scripts/extract-ikconfig",
79	},
80	{
81	    "file" => "kernel/configs.ko",
82	    "exec" => "scripts/extract-ikconfig",
83	    "test" => "scripts/extract-ikconfig",
84	},
85	{
86	    "file" => "kernel/configs.o",
87	    "exec" => "scripts/extract-ikconfig",
88	    "test" => "scripts/extract-ikconfig",
89	},
90);
91
92sub find_config {
93    foreach my $conf (@searchconfigs) {
94	my $file = $conf->{"file"};
95
96	next if ( ! -f "$file");
97
98	if (defined($conf->{"test"})) {
99	    `$conf->{"test"} $conf->{"file"} 2>/dev/null`;
100	    next if ($?);
101	}
102
103	my $exec = $conf->{"exec"};
104
105	print STDERR "using config: '$file'\n";
106
107	open(CIN, "$exec $file |") || die "Failed to run $exec $file";
108	return;
109    }
110    die "No config file found";
111}
112
113find_config;
114
115# Get the build source and top level Kconfig file (passed in)
116my $ksource = $ARGV[0];
117my $kconfig = $ARGV[1];
118my $lsmod_file = $ARGV[2];
119
120my @makefiles = `find $ksource -name Makefile 2>/dev/null`;
121chomp @makefiles;
122
123my %depends;
124my %selects;
125my %prompts;
126my %objects;
127my $var;
128my $iflevel = 0;
129my @ifdeps;
130
131# prevent recursion
132my %read_kconfigs;
133
134sub read_kconfig {
135    my ($kconfig) = @_;
136
137    my $state = "NONE";
138    my $config;
139    my @kconfigs;
140
141    my $cont = 0;
142    my $line;
143
144    my $source = "$ksource/$kconfig";
145    my $last_source = "";
146
147    # Check for any environment variables used
148    while ($source =~ /\$(\w+)/ && $last_source ne $source) {
149	my $env = $1;
150	$last_source = $source;
151	$source =~ s/\$$env/$ENV{$env}/;
152    }
153
154    open(KIN, "$source") || die "Can't open $kconfig";
155    while (<KIN>) {
156	chomp;
157
158	# Make sure that lines ending with \ continue
159	if ($cont) {
160	    $_ = $line . " " . $_;
161	}
162
163	if (s/\\$//) {
164	    $cont = 1;
165	    $line = $_;
166	    next;
167	}
168
169	$cont = 0;
170
171	# collect any Kconfig sources
172	if (/^source\s*"(.*)"/) {
173	    $kconfigs[$#kconfigs+1] = $1;
174	}
175
176	# configs found
177	if (/^\s*(menu)?config\s+(\S+)\s*$/) {
178	    $state = "NEW";
179	    $config = $2;
180
181	    for (my $i = 0; $i < $iflevel; $i++) {
182		if ($i) {
183		    $depends{$config} .= " " . $ifdeps[$i];
184		} else {
185		    $depends{$config} = $ifdeps[$i];
186		}
187		$state = "DEP";
188	    }
189
190	# collect the depends for the config
191	} elsif ($state eq "NEW" && /^\s*depends\s+on\s+(.*)$/) {
192	    $state = "DEP";
193	    $depends{$config} = $1;
194	} elsif ($state eq "DEP" && /^\s*depends\s+on\s+(.*)$/) {
195	    $depends{$config} .= " " . $1;
196
197	# Get the configs that select this config
198	} elsif ($state ne "NONE" && /^\s*select\s+(\S+)/) {
199	    if (defined($selects{$1})) {
200		$selects{$1} .= " " . $config;
201	    } else {
202		$selects{$1} = $config;
203	    }
204
205	# configs without prompts must be selected
206	} elsif ($state ne "NONE" && /^\s*tristate\s\S/) {
207	    # note if the config has a prompt
208	    $prompts{$config} = 1;
209
210	# Check for if statements
211	} elsif (/^if\s+(.*\S)\s*$/) {
212	    my $deps = $1;
213	    # remove beginning and ending non text
214	    $deps =~ s/^[^a-zA-Z0-9_]*//;
215	    $deps =~ s/[^a-zA-Z0-9_]*$//;
216
217	    my @deps = split /[^a-zA-Z0-9_]+/, $deps;
218
219	    $ifdeps[$iflevel++] = join ':', @deps;
220
221	} elsif (/^endif/) {
222
223	    $iflevel-- if ($iflevel);
224
225	# stop on "help"
226	} elsif (/^\s*help\s*$/) {
227	    $state = "NONE";
228	}
229    }
230    close(KIN);
231
232    # read in any configs that were found.
233    foreach $kconfig (@kconfigs) {
234	if (!defined($read_kconfigs{$kconfig})) {
235	    $read_kconfigs{$kconfig} = 1;
236	    read_kconfig($kconfig);
237	}
238    }
239}
240
241if ($kconfig) {
242    read_kconfig($kconfig);
243}
244
245sub convert_vars {
246    my ($line, %vars) = @_;
247
248    my $process = "";
249
250    while ($line =~ s/^(.*?)(\$\((.*?)\))//) {
251	my $start = $1;
252	my $variable = $2;
253	my $var = $3;
254
255	if (defined($vars{$var})) {
256	    $process .= $start . $vars{$var};
257	} else {
258	    $process .= $start . $variable;
259	}
260    }
261
262    $process .= $line;
263
264    return $process;
265}
266
267# Read all Makefiles to map the configs to the objects
268foreach my $makefile (@makefiles) {
269
270    my $line = "";
271    my %make_vars;
272
273    open(MIN,$makefile) || die "Can't open $makefile";
274    while (<MIN>) {
275	# if this line ends with a backslash, continue
276	chomp;
277	if (/^(.*)\\$/) {
278	    $line .= $1;
279	    next;
280	}
281
282	$line .= $_;
283	$_ = $line;
284	$line = "";
285
286	my $objs;
287
288	$_ = convert_vars($_, %make_vars);
289
290	# collect objects after obj-$(CONFIG_FOO_BAR)
291	if (/obj-\$\((CONFIG_[^\)]*)\)\s*[+:]?=\s*(.*)/) {
292	    $var = $1;
293	    $objs = $2;
294
295	# check if variables are set
296	} elsif (/^\s*(\S+)\s*[:]?=\s*(.*\S)/) {
297	    $make_vars{$1} = $2;
298	}
299	if (defined($objs)) {
300	    foreach my $obj (split /\s+/,$objs) {
301		$obj =~ s/-/_/g;
302		if ($obj =~ /(.*)\.o$/) {
303		    # Objects may be enabled by more than one config.
304		    # Store configs in an array.
305		    my @arr;
306
307		    if (defined($objects{$1})) {
308			@arr = @{$objects{$1}};
309		    }
310
311		    $arr[$#arr+1] = $var;
312
313		    # The objects have a hash mapping to a reference
314		    # of an array of configs.
315		    $objects{$1} = \@arr;
316		}
317	    }
318	}
319    }
320    close(MIN);
321}
322
323my %modules;
324
325if (defined($lsmod_file)) {
326    if ( ! -f $lsmod_file) {
327	die "$lsmod_file not found";
328    }
329    if ( -x $lsmod_file) {
330	# the file is executable, run it
331	open(LIN, "$lsmod_file|");
332    } else {
333	# Just read the contents
334	open(LIN, "$lsmod_file");
335    }
336} else {
337
338    # see what modules are loaded on this system
339    my $lsmod;
340
341    foreach my $dir ( ("/sbin", "/bin", "/usr/sbin", "/usr/bin") ) {
342	if ( -x "$dir/lsmod" ) {
343	    $lsmod = "$dir/lsmod";
344	    last;
345	}
346}
347    if (!defined($lsmod)) {
348	# try just the path
349	$lsmod = "lsmod";
350    }
351
352    open(LIN,"$lsmod|") || die "Can not call lsmod with $lsmod";
353}
354
355while (<LIN>) {
356	next if (/^Module/);  # Skip the first line.
357	if (/^(\S+)/) {
358		$modules{$1} = 1;
359	}
360}
361close (LIN);
362
363# add to the configs hash all configs that are needed to enable
364# a loaded module.
365my %configs;
366foreach my $module (keys(%modules)) {
367    if (defined($objects{$module})) {
368	my @arr = @{$objects{$module}};
369	foreach my $conf (@arr) {
370	    $configs{$conf} = $module;
371	}
372    } else {
373	# Most likely, someone has a custom (binary?) module loaded.
374	print STDERR "$module config not found!!\n";
375    }
376}
377
378my $valid = "A-Za-z_0-9";
379my $repeat = 1;
380
381#
382# Note, we do not care about operands (like: &&, ||, !) we want to add any
383# config that is in the depend list of another config. This script does
384# not enable configs that are not already enabled. If we come across a
385# config A that depends on !B, we can still add B to the list of depends
386# to keep on. If A was on in the original config, B would not have been
387# and B would not be turned on by this script.
388#
389sub parse_config_dep_select
390{
391    my ($p) = @_;
392
393    while ($p =~ /[$valid]/) {
394
395	if ($p =~ /^[^$valid]*([$valid]+)/) {
396	    my $conf = "CONFIG_" . $1;
397
398	    $p =~ s/^[^$valid]*[$valid]+//;
399
400	    if (!defined($configs{$conf})) {
401		# We must make sure that this config has its
402		# dependencies met.
403		$repeat = 1; # do again
404		$configs{$conf} = 1;
405	    }
406	} else {
407	    die "this should never happen";
408	}
409    }
410}
411
412while ($repeat) {
413    $repeat = 0;
414
415    foreach my $config (keys %configs) {
416	$config =~ s/^CONFIG_//;
417
418	if (defined($depends{$config})) {
419	    # This config has dependencies. Make sure they are also included
420	    parse_config_dep_select $depends{$config};
421	}
422
423	if (defined($prompts{$config}) || !defined($selects{$config})) {
424	    next;
425	}
426
427	# config has no prompt and must be selected.
428	parse_config_dep_select $selects{$config};
429    }
430}
431
432my %setconfigs;
433
434# Finally, read the .config file and turn off any module enabled that
435# we could not find a reason to keep enabled.
436while(<CIN>) {
437
438    if (/CONFIG_IKCONFIG/) {
439	if (/# CONFIG_IKCONFIG is not set/) {
440	    # enable IKCONFIG at least as a module
441	    print "CONFIG_IKCONFIG=m\n";
442	    # don't ask about PROC
443	    print "# CONFIG_IKCONFIG_PROC is not set\n";
444	} else {
445	    print;
446	}
447	next;
448    }
449
450    if (/^(CONFIG.*)=(m|y)/) {
451	if (defined($configs{$1})) {
452	    $setconfigs{$1} = $2;
453	} elsif ($2 eq "m") {
454	    print "# $1 is not set\n";
455	    next;
456	}
457    }
458    print;
459}
460close(CIN);
461
462# Integrity check, make sure all modules that we want enabled do
463# indeed have their configs set.
464loop:
465foreach my $module (keys(%modules)) {
466    if (defined($objects{$module})) {
467	my @arr = @{$objects{$module}};
468	foreach my $conf (@arr) {
469	    if (defined($setconfigs{$conf})) {
470		next loop;
471	    }
472	}
473	print STDERR "module $module did not have configs";
474	foreach my $conf (@arr) {
475	    print STDERR " " , $conf;
476	}
477	print STDERR "\n";
478    }
479}
480