New code to read kernel config in make_kconfig.pl

From: Trent Piepho <xyzzy@speakeasy.org>

New code to read the Kernel's (or v4l-dvb's) '.config' file.  This
replaces the code that used to read the config.h/autoconf.h file.  In
2.6.18 the autoconf.h file no longer mentions options set to 'n' at all,
while .config has a comment line for each disabled option.  Reading
.config is easier and gives us a list of the disabled options.

Restructure the code for reading '.version' too.

Signed-off-by: Trent Piepho <xyzzy@speakeasy.org>

1 files changed, 36 insertions, 51 deletions

diff --git a/v4l/scripts/make_kconfig.pl b/v4l/scripts/make_kconfig.pl
index 950e620d4..066df6a0e 100755
--- a/v4l/scripts/make_kconfig.pl
+++ b/v4l/scripts/make_kconfig.pl
@@ -14,58 +14,34 @@ my $version, $level, $sublevel, $kernver;
 my $kernel=shift;
 my $force_kconfig=shift;
 
-#my $debug=1;
-
-#!/usr/bin/perl
-use FileHandle;
+my $debug=0;
 
 ###########################################################
-# Checks config.h and autoconf.h for current kernel defines
+# Read a .config file (first argument) and put the resulting options in a
+# hash which is returned.  This subroutine should be called in a hash
+# context or it will not be very useful.
 sub process_config ($)
 {
 	my $filename = shift;
+	my %conf;
 	my $in = new FileHandle;
 
-	open $in,"$kernel/include/$filename" or die "File not found: $kernel/include/$filename";
+	open $in, $filename or die "File not found: $filename";
 	while (<$in>) {
-		if (m/\#define\s+CONFIG_([^ ]*)_ON_SMP\s+(.*)\n/) {
-			my $key=$1;
-			my $value=$2;
-			printf "defined $key as $value\n" if $debug;
-			if ( $value == 1 ) {
-				$value='y';
-			}
-			$kernopts{$key}=$value;
+		if (/^CONFIG_(\w+)\s*=\s*(\S.*?)\s*$/) {
+			$conf{$1} = $2;
 			next;
 		}
-		if (m/\#define\s+CONFIG_([^ ]*)_MODULE\s+(.*)\n/) {
-			my $key=$1;
-			my $value=$2;
-			printf "defined $key as $value\n" if $debug;
-			if ( $value == 1 ) {
-				$value='m';
-			}
-			$kernopts{$key}=$value;
+		if (/^# CONFIG_(\w+) is not set$/) {
+			$conf{$1} = 'n';
 			next;
 		}
-		if (m/\#define\s+CONFIG_([^ ]*)\s+(.*)\n/) {
-			my $key=$1;
-			my $value=$2;
-			printf "defined $key as $value\n" if $debug;
-			if ( $value == 1 ) {
-				$value='y';
-			}
-			$kernopts{$key}=$value;
-			next;
-		}
-		if (m/\#undef\s+CONFIG_([^ ]*)\n/) {
-			printf "undefined $1\n" if $debug;
-			$kernopts{$1}='n';
-			next;
+		unless (/^#|$/) {
+			print "Confused by this line in $filename:\n$_";
 		}
 	}
-
 	close $in;
+	return %conf;
 }
 
 sub add_bool($)
@@ -301,12 +277,12 @@ EOF
 	close $in;
 }
 
-sub parse_versions ()
+sub parse_versions()
 {
 	my $in = new FileHandle;
 	my $ver;
 
-	open $in,"versions.txt" or die "File not found: versions.txt";
+	open $in, "versions.txt" or die "File not found: versions.txt";
 	while (<$in>) {
 		if (/\[(\d+\.\d+\.\d+)\]/) {
 			$ver = $1;
@@ -318,6 +294,21 @@ sub parse_versions ()
 	close $in;
 }
 
+# Read in the .version file to get the kernel version
+sub get_version()
+{
+	open IN, '<.version' or die 'File not found: .version';
+	while (<IN>) {
+		if (/KERNELRELEASE\s*[:]*[=]+\s*(\d+)\.(\d+)\.(\d+)/) {
+			$version=$1;
+			$level=$2;
+			$sublevel=$3;
+			return $kernver="$version.$level.$sublevel";
+		}
+	}
+	close IN;
+}
+
 # Like ver1 <=> ver2, but understands X.Y.Z version strings
 sub cmp_ver($$)
 {
@@ -333,20 +324,14 @@ sub cmp_ver($$)
 	return $v1_sublevel <=> $v2_sublevel;
 }
 
-process_config("linux/autoconf.h");
+# Get kernel's config settings
+%kernopts = process_config("$kernel/.config");
 
-parse_versions;
+# Get minimum kernel version for our variables
+parse_versions();
 
-open IN,".version" or die "File not found: .version";
-while (<IN>) {
-	if (m/KERNELRELEASE\s*[:]*[=]+\s*(\d+)\.(\d+)\.(\d+)/) {
-		$version=$1;
-		$level=$2;
-		$sublevel=$3;
-		$kernver="$version.$level.$sublevel";
-	}
-}
-close IN;
+# Get kernel version
+get_version();
 
 print "Preparing to compile for kernel version $kernver\n";