pyrox.dev
1# This script runs `make config' to generate a Linux kernel
2# configuration file. For each question (i.e. kernel configuration
3# option), unless an override is provided, it answers "m" if possible,
4# and otherwise uses the default answer (as determined by the default
5# config for the architecture). Overrides are read from the file
6# $KERNEL_CONFIG, which on each line contains an option name and an
7# answer, e.g. "EXT2_FS_POSIX_ACL y". The script warns about ignored
8# options in $KERNEL_CONFIG, and barfs if `make config' selects
9# another answer for an option than the one provided in
10# $KERNEL_CONFIG.
11
12use strict;
13use IPC::Open2;
14use Cwd;
15
16# exported via nix
17my $debug = $ENV{'DEBUG'};
18my $autoModules = $ENV{'AUTO_MODULES'};
19my $preferBuiltin = $ENV{'PREFER_BUILTIN'};
20my $ignoreConfigErrors = $ENV{'ignoreConfigErrors'};
21my $buildRoot = $ENV{'BUILD_ROOT'};
22$SIG{PIPE} = 'IGNORE';
23
24# Read the answers.
25my %answers;
26my %requiredAnswers;
27open ANSWERS, "<$ENV{KERNEL_CONFIG}" or die "Could not open answer file";
28while (<ANSWERS>) {
29 chomp;
30 s/#.*//;
31 if (/^\s*([A-Za-z0-9_]+)(\?)?\s+(\S+)\s*$/) {
32 $answers{$1} = $3;
33 $requiredAnswers{$1} = !(defined $2);
34 } elsif (!/^\s*$/) {
35 die "invalid config line: $_";
36 }
37}
38close ANSWERS;
39
40sub runConfig {
41
42 # Run `make config'.
43 my $pid = open2(\*IN, \*OUT, "make -C $ENV{SRC} O=$buildRoot config SHELL=bash ARCH=$ENV{ARCH}");
44
45 # Parse the output, look for questions and then send an
46 # appropriate answer.
47 my $line = ""; my $s;
48 my %choices = ();
49
50 my ($prevQuestion, $prevName);
51
52 while (!eof IN) {
53 read IN, $s, 1 or next;
54 $line .= $s;
55
56 #print STDERR "LINE: $line\n";
57
58 if ($s eq "\n") {
59 print STDERR "GOT: $line" if $debug;
60
61 # Remember choice alternatives ("> 1. bla (FOO)" or " 2. bla (BAR) (NEW)").
62 if ($line =~ /^\s*>?\s*(\d+)\.\s+.*?\(([A-Za-z0-9_]+)\)(?:\s+\(NEW\))?\s*$/) {
63 $choices{$2} = $1;
64 }
65
66 $line = "";
67 }
68
69 elsif ($line =~ /###$/) {
70 # The config program is waiting for an answer.
71
72 # Is this a regular question? ("bla bla (OPTION_NAME) [Y/n/m/...] ")
73 if ($line =~ /(.*) \(([A-Za-z0-9_]+)\) \[(.*)\].*###$/) {
74 my $question = $1; my $name = $2; my $alts = $3;
75 my $answer = "";
76 # Build everything as a module if possible.
77 $answer = "m" if $autoModules && $alts =~ /\/m/ && !($preferBuiltin && $alts =~ /Y/);
78 $answer = $answers{$name} if defined $answers{$name};
79 print STDERR "QUESTION: $question, NAME: $name, ALTS: $alts, ANSWER: $answer\n" if $debug;
80 print OUT "$answer\n";
81 die "repeated question: $question" if $prevQuestion && $prevQuestion eq $question && $name eq $prevName;
82 $prevQuestion = $question;
83 $prevName = $name;
84 }
85
86 # Is this a choice? ("choice[1-N]: ")
87 elsif ($line =~ /choice\[(.*)\]: ###$/) {
88 my $answer = "";
89 foreach my $name (keys %choices) {
90 $answer = $choices{$name} if ($answers{$name} || "") eq "y";
91 }
92 print STDERR "CHOICE: $1, ANSWER: $answer\n" if $debug;
93 print OUT "$answer\n" if $1 =~ /-/;
94 }
95
96 # Some questions lack the option name ("bla bla [Y/n/m/...] ").
97 elsif ($line =~ /(.*) \[(.*)\] ###$/) {
98 print OUT "\n";
99 }
100
101 else {
102 warn "don't know how to answer this question: $line\n";
103 print OUT "\n";
104 }
105
106 $line = "";
107 %choices = ();
108 }
109 }
110
111 close IN;
112 waitpid $pid, 0;
113}
114
115# Run `make config' several times to converge on the desired result.
116# (Some options may only become available after other options are
117# set in a previous run.)
118runConfig;
119runConfig;
120
121# Read the final .config file and check that our answers are in
122# there. `make config' often overrides answers if later questions
123# cause options to be selected.
124my %config;
125open CONFIG, "<$buildRoot/.config" or die "Could not read .config";
126while (<CONFIG>) {
127 chomp;
128 if (/^CONFIG_([A-Za-z0-9_]+)="(.*)"$/) {
129 # String options have double quotes, e.g. 'CONFIG_NLS_DEFAULT="utf8"' and allow escaping.
130 ($config{$1} = $2) =~ s/\\([\\"])/$1/g;
131 } elsif (/^CONFIG_([A-Za-z0-9_]+)=(.*)$/) {
132 $config{$1} = $2;
133 } elsif (/^# CONFIG_([A-Za-z0-9_]+) is not set$/) {
134 $config{$1} = "n";
135 }
136}
137close CONFIG;
138
139foreach my $name (sort (keys %answers)) {
140 my $f = $requiredAnswers{$name} && $ignoreConfigErrors ne "1"
141 ? sub { die "error: " . $_[0]; } : sub { warn "warning: " . $_[0]; };
142 &$f("unused option: $name\n") unless defined $config{$name};
143 &$f("option not set correctly: $name (wanted '$answers{$name}', got '$config{$name}')\n")
144 if $config{$name} && $config{$name} ne $answers{$name};
145}