1 files changed, 145 insertions, 0 deletions
diff --git a/nixpkgs/pkgs/os-specific/linux/kernel/generate-config.pl b/nixpkgs/pkgs/os-specific/linux/kernel/generate-config.pl
new file mode 100644
index 000000000000..f886fcfdc358
--- /dev/null
+++ b/nixpkgs/pkgs/os-specific/linux/kernel/generate-config.pl
@@ -0,0 +1,145 @@
+# This script runs `make config' to generate a Linux kernel
+# configuration file.  For each question (i.e. kernel configuration
+# option), unless an override is provided, it answers "m" if possible,
+# and otherwise uses the default answer (as determined by the default
+# config for the architecture).  Overrides are read from the file
+# $KERNEL_CONFIG, which on each line contains an option name and an
+# answer, e.g. "EXT2_FS_POSIX_ACL y".  The script warns about ignored
+# options in $KERNEL_CONFIG, and barfs if `make config' selects
+# another answer for an option than the one provided in
+# $KERNEL_CONFIG.
+
+use strict;
+use IPC::Open2;
+use Cwd;
+
+# exported via nix
+my $debug = $ENV{'DEBUG'};
+my $autoModules = $ENV{'AUTO_MODULES'};
+my $preferBuiltin = $ENV{'PREFER_BUILTIN'};
+my $ignoreConfigErrors = $ENV{'ignoreConfigErrors'};
+my $buildRoot = $ENV{'BUILD_ROOT'};
+$SIG{PIPE} = 'IGNORE';
+
+# Read the answers.
+my %answers;
+my %requiredAnswers;
+open ANSWERS, "<$ENV{KERNEL_CONFIG}" or die "Could not open answer file";
+while (<ANSWERS>) {
+    chomp;
+    s/#.*//;
+    if (/^\s*([A-Za-z0-9_]+)(\?)?\s+(\S+)\s*$/) {
+        $answers{$1} = $3;
+        $requiredAnswers{$1} = !(defined $2);
+    } elsif (!/^\s*$/) {
+        die "invalid config line: $_";
+    }
+}
+close ANSWERS;
+
+sub runConfig {
+
+    # Run `make config'.
+    my $pid = open2(\*IN, \*OUT, "make -C $ENV{SRC} O=$buildRoot config SHELL=bash ARCH=$ENV{ARCH}");
+
+    # Parse the output, look for questions and then send an
+    # appropriate answer.
+    my $line = ""; my $s;
+    my %choices = ();
+
+    my ($prevQuestion, $prevName);
+
+    while (!eof IN) {
+        read IN, $s, 1 or next;
+        $line .= $s;
+
+        #print STDERR "LINE: $line\n";
+
+        if ($s eq "\n") {
+            print STDERR "GOT: $line" if $debug;
+
+            # Remember choice alternatives ("> 1. bla (FOO)" or " 2. bla (BAR) (NEW)").
+            if ($line =~ /^\s*>?\s*(\d+)\.\s+.*?\(([A-Za-z0-9_]+)\)(?:\s+\(NEW\))?\s*$/) {
+                $choices{$2} = $1;
+            }
+
+            $line = "";
+        }
+
+        elsif ($line =~ /###$/) {
+            # The config program is waiting for an answer.
+
+            # Is this a regular question? ("bla bla (OPTION_NAME) [Y/n/m/...] ")
+            if ($line =~ /(.*) \(([A-Za-z0-9_]+)\) \[(.*)\].*###$/) {
+                my $question = $1; my $name = $2; my $alts = $3;
+                my $answer = "";
+                # Build everything as a module if possible.
+                $answer = "m" if $autoModules && $alts =~ /\/m/ && !($preferBuiltin && $alts =~ /Y/);
+                $answer = $answers{$name} if defined $answers{$name};
+                print STDERR "QUESTION: $question, NAME: $name, ALTS: $alts, ANSWER: $answer\n" if $debug;
+                print OUT "$answer\n";
+                die "repeated question: $question" if $prevQuestion && $prevQuestion eq $question && $name eq $prevName;
+                $prevQuestion = $question;
+                $prevName = $name;
+            }
+
+            # Is this a choice? ("choice[1-N]: ")
+            elsif ($line =~ /choice\[(.*)\]: ###$/) {
+                my $answer = "";
+                foreach my $name (keys %choices) {
+                    $answer = $choices{$name} if ($answers{$name} || "") eq "y";
+                }
+                print STDERR "CHOICE: $1, ANSWER: $answer\n" if $debug;
+                print OUT "$answer\n" if $1 =~ /-/;
+            }
+
+            # Some questions lack the option name ("bla bla [Y/n/m/...] ").
+            elsif ($line =~ /(.*) \[(.*)\] ###$/) {
+                print OUT "\n";
+            }
+
+            else {
+                warn "don't know how to answer this question: $line\n";
+                print OUT "\n";
+            }
+
+            $line = "";
+            %choices = ();
+        }
+    }
+
+    close IN;
+    waitpid $pid, 0;
+}
+
+# Run `make config' several times to converge on the desired result.
+# (Some options may only become available after other options are
+# set in a previous run.)
+runConfig;
+runConfig;
+
+# Read the final .config file and check that our answers are in
+# there.  `make config' often overrides answers if later questions
+# cause options to be selected.
+my %config;
+open CONFIG, "<$buildRoot/.config" or die "Could not read .config";
+while (<CONFIG>) {
+    chomp;
+    if (/^CONFIG_([A-Za-z0-9_]+)="(.*)"$/) {
+        # String options have double quotes, e.g. 'CONFIG_NLS_DEFAULT="utf8"' and allow escaping.
+        ($config{$1} = $2) =~ s/\\([\\"])/$1/g;
+    } elsif (/^CONFIG_([A-Za-z0-9_]+)=(.*)$/) {
+        $config{$1} = $2;
+    } elsif (/^# CONFIG_([A-Za-z0-9_]+) is not set$/) {
+        $config{$1} = "n";
+    }
+}
+close CONFIG;
+
+foreach my $name (sort (keys %answers)) {
+    my $f = $requiredAnswers{$name} && $ignoreConfigErrors ne "1"
+        ? sub { die "error: " . $_[0]; } : sub { warn "warning: " . $_[0]; };
+    &$f("unused option: $name\n") unless defined $config{$name};
+    &$f("option not set correctly: $name (wanted '$answers{$name}', got '$config{$name}')\n")
+        if $config{$name} && $config{$name} ne $answers{$name};
+}