#! /usr/bin/perl -w
# 
# $Id$
# Check and possibly rebuild lufs kernel module for the current kernel.
# Copyright (C) 2003 Jan Kratochvil <project-captive@jankratochvil.net>
# 
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; exactly version 2 of June 1991 is required
# 
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
# 
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA


use strict;
use Carp qw(cluck confess);
use Getopt::Long;
# Do not use any non-core Perl modules here.
# Be perl-5.0 compatible (is it needed if we require Linux kernel >= 2.4 ?)


my $basedir='@datadir@/lufs';
my $vardir='@localstatedir@/lib/lufs';
$basedir=~s#\$\Q{prefix}\E#'@prefix@';#ge;
$vardir=~s#\$\Q{prefix}\E#'@prefix@';#ge;
$vardir="" if $vardir=~/^@/;
sub srcdir { my($uname_r)=@_; $basedir."/".($uname_r lt "2.5" ? "2.4" : "2.5"); }
my $modbindir=$basedir."/modbin";
my @sources=qw(proc.c inode.c dir.c file.c symlink.c);
my $tmp_dir="prepmod-tmp-dir";

my $quiet;
my $kernel;
my $prebuild;
use vars qw($kernel_gcc_args);
$kernel_gcc_args="";

my $lufsmnt_bin;
if ($0 eq "lufsmnt" || $0=~m#/lufsmnt$#) {
	$quiet=1;
	$lufsmnt_bin='@bindir@/lufsmnt-bin';
	$lufsmnt_bin=~s#\$\Q{exec_prefix}\E#'@exec_prefix@';#ge;
	$lufsmnt_bin=~s#\$\Q{prefix}\E#'@prefix@';#ge;
	}
else {
	die if !GetOptions(
			"q|quiet",\$quiet,
			  "kernel",\$kernel,	# it must contain "include" subdir
			  "modbindir=s",\$modbindir,
			  "basedir=s",\$basedir,
			  "prebuild",\&prebuild,
			  "kernel-gcc-args=s",\$kernel_gcc_args,
			);
	}


sub _readfile
{
my($filename,$optional)=@_;

	local $/=undef();
	local *F;
	open F,$filename or do { cluck "Open \"$filename\": $!" if !$optional; return ""; };
	my $r=<F>;
	close F or cluck "Close \"$filename\": $!";
	return $r;
}

sub _writefile
{
my($filename,@content)=@_;

	local *F;
	open F,($filename=~/^[|]/ ? "" : ">").$filename or confess "rewrite \"$filename\": $!";
	print F @content;
	close F or confess "close \"$filename\": $!";	# Do not &cluck as it may be pipe result
}

sub _system
{
my(@args)=@_;

	print STDERR "+ ".join(" ",@args)."\n" if !$quiet;
	return system @args;
}

sub _pass
{
my($load)=@_;

	my $modproberc;
	if ($load) {
		do { ($modproberc=_system $_) and cluck "$_ failed - ignoring"; }
				for ("/sbin/depmod -aq","/sbin/modprobe lufs");
		}
	exit ($modproberc ? 1 : 0) if !$lufsmnt_bin;
	do { exec $lufsmnt_bin,@ARGV; };
	confess "Failed to exec '$lufsmnt_bin': $!";
}


my $filesystems=_readfile "/proc/filesystems";	# 'lufs' may be built-in
_pass if $filesystems=~/\blufs$/m;
my $modules=_readfile "/proc/modules";	# 'lufs' may be already loaded
_pass if $modules=~/^lufs\b/m;
_pass if !_system "/sbin/modprobe lufs 2>/dev/null";

my $proc_version=_readfile "/proc/version";
my $uname_r=($proc_version=~/^Linux version (\S+)/)[0] || _readfile "uname -r|";
chomp $uname_r;
confess "Failed to detect kernel version" if !$uname_r;
my $uname_r_base=($uname_r=~/^([^-]+)/)[0];
print STDERR "Running kernel version: $uname_r (base version $uname_r_base)\n" if !$quiet;

my $moduledir="/lib/modules/$uname_r/kernel/fs/lufs";
print STDERR "Destination module directory: $moduledir\n" if !$quiet;

do { $kernel||=$_ if -d $_; } for ("/lib/modules/$uname_r/build");
do { $kernel||=$_ if -d $_; } for ("/usr/src/kernel-headers-$uname_r");
do { $kernel||=$_ if -d $_; } for ("/usr/src/linux-$uname_r");
do { $kernel||=$_ if -d $_; } for ("/usr/src/linux-$uname_r_base");
do { $kernel||=$_ if -d $_; } for ("/usr/src/linux");
if (!$kernel) {
	print STDERR "Failed to find kernel headers for $uname_r\n" if !$kernel && !$quiet;
	}
else {
	# We need /usr/include/lufs/* for standard package compilation.
	# There is no sense to make separate 'devel' package.
	for ("$vardir/lufs.o") {
		next if !$vardir;
		# Create the 'lufs.o' in our /var/lib directory and only link it
		# to prevent using obsolete modules after upgrading 'lufs' package.
		# depmod(1) will take the larget symlink name - we must create directory for  it.
		if (build($kernel,$uname_r,$_)) {
			do { cluck "Failed to symlink $_"; next; }
					if _system "/bin/rm -rf $moduledir; /bin/mkdir -p $moduledir; /bin/ln -s $_ $moduledir/lufs.o";
			_pass 1;
			}
		}
	}

local $_;
for (<$modbindir/*-$uname_r*/*.o>,<$modbindir/*-${uname_r_base}*/*.o>,<$modbindir/*/*.o>) {
	next if _system "/sbin/rmmod lufs 2>/dev/null; /sbin/insmod -o lufs -p $_ 2>/dev/null";
	do { cluck "Failed to symlink $_"; next; }
			if _system "/bin/rm -rf $moduledir; /bin/mkdir -p $moduledir; /bin/ln -s $_ $moduledir/lufs.o";
	_pass 1;
	}
confess "lufs module not loaded: Try running $basedir/prepmod to see more.";


sub build
{
my($kernel,$uname_r,$destmodule)=@_;

	print STDERR "Using kernel sources: $kernel\n" if !$quiet;
	confess "Kernel sources $kernel do not contain 'include' subdirectory" if ! -d $kernel."/include";

	my $kdebug="";
	do { $kdebug=$_ if !/^@/; } for ('@KDEBUG_FLAGS@');
	my $cmdline="/usr/bin/gcc"
			.($quiet ? " 2>/dev/null" : "")
			." -Wall -Wstrict-prototypes -Wno-trigraphs"
			." -O2 -fno-strict-aliasing -fno-common -fomit-frame-pointer -pipe -mpreferred-stack-boundary=2"
			#." -march=i586"
			." -D__KERNEL__ -DMODULE -DLINUX -DKBUILD_MODNAME=lufs"
			." ".$kdebug
			." ".$kernel_gcc_args
			." -I$kernel/include"
			." -I$kernel/include/asm-i386/mach-default";	# gcc should not care if this 2.5 dir does not exist

	my $config=_readfile "$kernel/.config","optional";
	my $autoconf=_readfile "$kernel/include/linux/autoconf.h","optional";
	$cmdline.=" -DMODVERSIONS -include $kernel/include/linux/modversions.h"
			if 0
					|| $config=~/^CONFIG_MODVERSIONS=y\b/m
					|| $autoconf=~/^#define CONFIG_MODVERSIONS\b/m
					|| (!$config && !$autoconf);	# assume modversions if not known

	my @objects=map({ my $o=$_; $o=~s/[.]c$/.o/; $o; } @sources);
	return !_system "set -e; /bin/mkdir -p `dirname $destmodule`; /bin/rm -f $destmodule;"
			.(!$vardir ? "" : " cd $vardir;")
			." $cmdline -c ".join(" ",map({ srcdir($uname_r)."/".$_; } @sources)).";"
			." /usr/bin/ld -r -o $destmodule ".join(" ",@objects).";"
			." /bin/rm -f ".join(" ",@objects);
}


sub prebuild_kernel
{
my($dir,$vendor,$uname_r)=@_;

	confess "Unrecognized vendor for dir: $dir" if !$vendor;
	confess "Unrecognized uname_r for dir: $dir" if !$uname_r;
	confess "Failed to build $dir" if !build $dir,$uname_r,$modbindir."/lufs-$vendor-$uname_r.o";
}


sub prebuild_rpm
{
my($rpm)=@_;

	my $vendor=_readfile "rpm 2>/dev/null --qf '%{VENDOR}' -qp '$rpm' |";
	$vendor=~s/,.*//;
	$vendor=~tr/ //d;
	my $uname_r;
	$uname_r||=($rpm=~m#/kernel-source-([^-]+-[^-]+)[.][^.]+[.]rpm$#)[0];
	my $uname_r_base=($uname_r=~/^([^-]+)/)[0];
	_system "/bin/rm -rf $tmp_dir; /bin/mkdir $tmp_dir; set -e;"
			# Here we will extract even some false 'include's but we filter dirs just for speed/space.
			." /usr/bin/rpm2cpio '$rpm' | (cd $tmp_dir; /bin/cpio -id --quiet ./usr/src/linux*/{.config,include/*})"
			and confess "Extraction of: $rpm";
	my $dir;
	do { $dir||=$_ if -d $_; } for ($tmp_dir."/usr/src/linux-$uname_r");
	do { $dir||=$_ if -d $_; } for ($tmp_dir."/usr/src/linux-$uname_r_base");	# older RedHat kernels
	$dir or confess "Kernel source tree not found in: $rpm";
	_writefile "| patch $dir/include/linux/rhconfig.h",<<'RHCONFIG_H_NOBOOT_EOF';
--- ./include/linux/rhconfig.h-orig	Thu Aug 21 14:50:16 2003
+++ ./include/linux/rhconfig.h	Thu Aug 21 14:59:22 2003
@@ -10,7 +10,7 @@
  * /boot/kernel.h - initscripts should create it for us
  */
 
-#include "/boot/kernel.h"
+/* lufs: #include "/boot/kernel.h" */
 
 #if defined(__BOOT_KERNEL_SMP) && (__BOOT_KERNEL_SMP == 1)
 #define __module__smp
RHCONFIG_H_NOBOOT_EOF
	for my $smp ("","smp") {
		my @archs=qw(i386 i586 i686 athlon);
		for my $arch (@archs) {
			my %boot=(
					"__BOOT_KERNEL_SMP"=>$smp,
					map({ ("__MODULE_KERNEL_$_"=>($arch eq $_)); } @archs),
					"__BOOT_KERNEL_BOOT"=>0,
					"__BOOT_KERNEL_BOOTSMP"=>0,
					"__BOOT_KERNEL_ENTERPRISE"=>0,
					"__BOOT_KERNEL_BIGMEM"=>0,
					"__BOOT_KERNEL_DEBUG"=>0,
					);
			local $kernel_gcc_args=join(" ",map({ " -D$_=".($boot{$_} ? 1 : 0); } keys(%boot)))
					." -march=$arch"
					." ".$kernel_gcc_args;
			prebuild_kernel $dir,$vendor,$uname_r.$smp.".".$arch;
			}
		}
	_system "/bin/rm -rf $tmp_dir" and confess "Deletion of: $tmp_dir";
}

sub prebuild_dir
{
my($dir)=@_;

	my $vendor;
	chomp (my $debian=_readfile "/etc/debian_version","optional");
	$debian=~tr#/#_#;
	$vendor="Debian".$debian if $debian && $dir=~m#^/usr/src/#;
	my $uname_r;
	$uname_r||=($dir=~m#/kernel-headers-([^/]+)/*$#)[0];
	$uname_r||=($dir=~m#/linux-([^/]+)/*$#)[0];
	$uname_r||=($dir=~m#^/lib/modules/([^/]+)/build/*$#)[0];
	prebuild_kernel $dir,$vendor,$uname_r;
}

sub prebuild
{
	$vardir=undef();	# we may not yet have /var/lib/lufs
	for (@ARGV) {
		do { prebuild_rpm $_; next; } if /[.]rpm$/;
		do { prebuild_dir $_; next; } if -d $_;
		confess "Unrecognized kernel: $_";
		}
	exit 0;
}