#!/usr/bin/perl

use strict;

$ENV{'PATH'} = "/bin:/usr/bin:/sbin:/usr/sbin";

$| = 1;

if ($0 ne '/.build/extractbuild') {
  my $builddir = $ENV{'BUILD_DIR'} || '/usr/lib/build';
  my $xen;
  my $xenswap;
  while (@ARGV) {
    if ($ARGV[0] eq '--xen') {
      shift @ARGV;
      $xen = shift @ARGV;
      next;
    }
    if ($ARGV[0] eq '--xenswap') {
      shift @ARGV;
      $xenswap = shift @ARGV;
      next;
    }
    last
  }
  die("please specify a root image\n") unless defined $xen;
  die("please specify a swap image\n") unless defined $xenswap;
  my $xenname = $xen;
  $xenname =~ s/\/root$//;
  $xenname =~ s/.*\///;
  my $xmroot = "disk=file:$xen,hda1,w";
  $xmroot = "disk=phy:$xen,hda1,w" if $xen =~ /^\/dev\//;
  my $xmswap= "disk=file:$xenswap,hda2,w";
  $xmswap= "disk=phy:$xen,hda2,w" if $xenswap =~ /^\/dev\//;
  syscall(135, 0);	# switch back to PER_LINUX to make xm work
  system('xm', 'create', '-c', "$builddir/xen.conf", "name=build:$xenname", $xmroot, $xmswap, "extra=init=/.build/extractbuild panic=1 console=ttyS0") && die("xm call failed: $?\n");
  exit(0);
}

sub ls {
  local *D;
  opendir(D, $_[0]) || return ();
  my @r = grep {$_ ne '.' && $_ ne '..'} readdir(D);
  closedir D;
  return @r;
}

open(F, '</.build/build.data') || die("/.build/build.data: $!\n");
my (%vars, $var, $val);
my $l = '';
while (<F>) {
  chomp;
  $l .= $_;
  my $q = $l =~ tr/\'/\'/;
  if ($q < 2 || ($q - 2) % 3 != 0) {
    $l .= "\n";
    next;
  }
  if ($l =~ /^([a-zA-Z0-9]*)=\'(.*)\'$/s) {
    $var = $1;
    $val = $2;
    $val =~ s/\'\\\'\'/\'/gs;
    $vars{$var} = $val;
  }
  $l = '';
}
close F;

my $xenswap = $vars{'XENSWAP'};
die("need XENSWAP for swapout operation\n") unless $xenswap;
system("umount -l /dev 2>/dev/null");
die("$xenswap: $!\n") unless -e $xenswap;
open(S, '>', $xenswap) || die("$xenswap: $!\n");

my $specfile = $vars{'SPECFILE'};
die("no specfile/dscfile\n") unless $specfile;
my $topdir = '/usr/src/packages';
my $psuf = 'deb';
my @dirs = ($topdir);
if ($specfile =~ /\.spec$/) {
  $topdir = `rpm --eval '%_topdir'`;
  chomp $topdir;
  die("rpm returned no topdir\n") unless $topdir;
  die("rpm returned bad topdir\n") unless -d $topdir;
  @dirs = map {"$topdir/RPMS/$_"} ls("$topdir/RPMS");
  unshift @dirs, "$topdir/SRPMS";
  $psuf = 'rpm';
}
my @packs;
for my $dir (@dirs) {
  push @packs, map {"$dir/$_"} grep {/$psuf$/} ls($dir);
}
#unshift @packs, '/.build.log';

my $cpio = '';
for my $pack (@packs) {
  print "$pack\n";
  my @s = stat($pack);
  my $n = $pack;
  $n =~ s/.*\///;
  $n = 'logfile' if $n eq '.build.log';
  die("$pack: $!\n") unless @s;
  $cpio .= "07070100000000000081a4000000000000000000000001";
  $cpio .= sprintf("%08x%08x", $s[9], $s[7]);
  $cpio .= "00000000000000000000000000000000";
  $cpio .= sprintf("%08x", length($n) + 1);
  $cpio .= "00000000";
  $cpio .= "$n\0";
  $cpio .= substr("\0\0\0\0", (length($cpio) & 3)) if length($cpio) & 3;
  open(F, '<', $pack) || die("$pack: $!\n");
  my $l = $s[7];
  while ($l) {
    my $ll = sysread(F, $cpio, $l > 8192 ? 8192 : $l, length($cpio));
    die("$pack: $!\n") unless $ll;
    die if $ll > $l;
    $l -= $ll;
    while (length($cpio) > 4096) {
      (syswrite(S, $cpio, 4096) || 0) == 4096 || die("swap write: $!\n");
      $cpio = substr($cpio, 4096);
    }
  }
  $cpio .= substr("\0\0\0\0", (length($cpio) & 3)) if length($cpio) & 3;
}
$cpio .= "07070100000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000b00000000TRAILER!!!\0\0\0\0";
$cpio .= "\0" x (4096 - length($cpio) % 4096) if length($cpio) % 4096;
while (length($cpio)) {
  (syswrite(S, $cpio, 4096) || 0) == 4096 || die("swap write: $!\n");
  $cpio = substr($cpio, 4096);
}
exec('halt -f');