#! /usr/bin/perl
# 
use strict;
use warnings;
use Cwd 'abs_path';

# Debconf may not be around here.
my $have_debconf = 0;
my $capb;

eval {require Debconf::Client::ConfModule;};
if ( ! $@ )
{
  $have_debconf++;
  import Debconf::Client::ConfModule ':all';
  version('2.0');
  $capb=capb("backup");
}

$|=1;
# Predefined values:
my $version           = "3.16.0-4-powerpc-smp";
my $link_in_boot      = "";
my $kimage            = "vmlinux";
my $postrm_hook       = '';       #Normally we do not
my $package_name    = "linux-image-$version";

#known variables
my $image_dest      = "/";
my $realimageloc    = "/boot/";
my $CONF_LOC        = '/etc/kernel-img.conf';

chdir('/')           or die "could not chdir to /:$!\n";


if (-r "$CONF_LOC" && -f "$CONF_LOC"  ) {
  if (open(CONF, "$CONF_LOC")) {
    while (<CONF>) {
      chomp;
      s/\#.*$//g;
      next if /^\s*$/;

      $link_in_boot    = "" if /link_in_boot\s*=\s*(no|false|0)\s*$/i;

      $link_in_boot    = "Yes" if /link_in_boot\s*=\s*(yes|true|1)\s*$/i;

      $image_dest      = "$1"  if /image_dest\s*=\s*(\S+)/i;
      $postrm_hook     = "$1"  if /postrm_hook\s*=\s*(\S+)/i;
    }
    close CONF;
  }
}

if ($link_in_boot) {
  $image_dest = $realimageloc;
}

$image_dest = "$image_dest/";
$image_dest =~ s|/+$|/|o;

# The destdir may be gone by now.
if (-d "$image_dest") {
  chdir("$image_dest") or die "could not chdir to $image_dest:$!\n";
}


######################################################################
######################################################################
############
######################################################################
######################################################################
sub remove_sym_link {
  my $bad_image = $_[0];

  warn "Removing symbolic link $bad_image \n";
  warn "You may need to re-run your boot loader\n";
  # Remove the dangling link
  unlink "$bad_image";
}

######################################################################
######################################################################
############
######################################################################
######################################################################
sub CanonicalizePath {
  my $path = join '/', @_;
  my @work = split '/', $path;
  my @out;
  my $is_absolute;

  if (@work && $work[0] eq "") { $is_absolute = 1; shift @work; }

  while (@work) {
    my $seg = shift @work;
    if ($seg eq "." || $seg eq "") {
    } elsif ($seg eq "..") {
      if (@out && $out[-1] ne "..") {
        pop @out;
      } else {
        # Leading "..", or "../..", etc.
        push @out, $seg;
      }
    } else {
      push @out, $seg;
    }
  }

  unshift @out, "" if $is_absolute;
  return join('/', @out);
}

######################################################################
######################################################################
############
######################################################################
######################################################################
# This removes dangling symlinks. What do we do about hard links? Surely a 
# something with the nane $image_dest . "$kimage" ought not to be left behind? 
sub image_magic {
  my $kimage = $_[0];
  my $image_dest = $_[1];

  if (-l "$kimage") {
    # There is a symbolic link
    my $force_move = 0;
    my $vmlinuz_target = readlink "$kimage";
    my $real_target = '';
    $real_target = abs_path($vmlinuz_target) if defined ($vmlinuz_target);
    if (!defined($vmlinuz_target) || ! -f "$real_target") {
      # what, a dangling symlink?
      warn "The link "  . $image_dest . "$kimage is a damaged link\n";
      # Remove the dangling link
      &remove_sym_link("$kimage");
    }
    else {
      my $canonical_target = CanonicalizePath("$vmlinuz_target");
      if (! -e $canonical_target) {
	warn "The link "  . $image_dest . "$kimage is a dangling link\n";
	&remove_sym_link("$kimage");
      }
    }
  }
}

# set the env var stem
$ENV{'STEM'} = "linux";

sub exec_script {
  my $type   = shift;
  my $script = shift;
  print STDERR "Running $type hook script $script.\n";
  system ("$script $version $realimageloc$kimage-$version") &&
    print STDERR "User $type hook script [$script] ";
  if ($?) {
    if ($? == -1) {
      print STDERR "failed to execute: $!\n";
    }
    elsif ($? & 127) {
      printf STDERR "died with signal %d, %s coredump\n",
        ($? & 127),  ($? & 128) ? 'with' : 'without';
    }
    else {
      printf STDERR "exited with value %d\n", $? >> 8;
    }
  }
}
sub run_hook {
  my $type   = shift;
  my $script = shift;
  if ($script =~ m,^/,) {
    # Full path provided for the hook script
    if (-x "$script") {
      &exec_script($type,$script);
    }
    else {
      warn "The provided $type hook script [$script] could not be run.\n";
    }
  }
  else {
    # Look for it in a safe path
    for my $path ('/bin', '/sbin', '/usr/bin', '/usr/sbin') {
      if (-x "$path/$script") {
        &exec_script($type, "$path/$script");
        return 0;
      }
    }
    # No luck
    print STDERR "Could not find $type hook script [$script].\n";
    warn "Looked in: '/bin', '/sbin', '/usr/bin', '/usr/sbin'\n";
  }
}

my $options;
for (@ARGV) {
	s,','\\'',g;
	$options .= " '$_'";
}
$ENV{'DEB_MAINT_PARAMS'}="$options";

## Run user hook script here, if any
if ($postrm_hook) {
  &run_hook("postrm", $postrm_hook);
}
if (-d "/etc/kernel/postrm.d") {
  system ("run-parts --report --exit-on-error --arg=$version " .
          "--arg=$realimageloc$kimage-$version " .
          "/etc/kernel/postrm.d") &&
            die "Failed to process /etc/kernel/postrm.d";
}
if (-d "/etc/kernel/postrm.d/$version") {
  system ("run-parts --report --exit-on-error --arg=$version " .
          "--arg=$realimageloc$kimage-$version " .
          "/etc/kernel/postrm.d/$version") &&
            die "Failed to process /etc/kernel/postrm.d/$version";
}

# purge initramfs and related
if ($ARGV[0] !~ /upgrade/) {
  if (-f $realimageloc . "initrd.img-$version") {
    unlink $realimageloc . "initrd.img-$version";
  }
  if (-f $realimageloc . "initrd.img-$version.bak") {
    unlink $realimageloc . "initrd.img-$version.bak";
  }
  if (-f "/var/lib/initramfs-tools/$version") {
    unlink "/var/lib/initramfs-tools/$version";
  }
  # check and remove damaged and dangling symlinks
  image_magic($kimage,          $image_dest);
  image_magic($kimage . ".old", $image_dest);
  image_magic("initrd.img",     $image_dest);
  image_magic("initrd.img.old", $image_dest);
}


# Ignore all invocations except when called on to purge.
exit 0 unless $ARGV[0] =~ /purge/;

my $ret = purge();

my @files_to_remove = qw{
                         modules.dep modules.isapnpmap modules.pcimap
                         modules.usbmap modules.parportmap
                         modules.generic_string modules.ieee1394map
                         modules.ieee1394map modules.pnpbiosmap
                         modules.alias modules.ccwmap modules.inputmap
                         modules.symbols modules.ofmap
                         modules.seriomap modules.*.bin
			 modules.softdep modules.devname
                       };

foreach my $extra_file (@files_to_remove) {
  for (glob("/lib/modules/$version/$extra_file")) {
    unlink;
  }
}

if (-d "/lib/modules/$version" ) {
  system ("rmdir", "/lib/modules/$version");
}

exit 0;

__END__