#! /usr/bin/perl
#                              -*- Mode: Cperl -*-
# image.postrm ---
# Author           : Manoj Srivastava ( srivasta@glaurung.green-gryphon.com )
# Created On       : Sat May 15 11:05:13 1999
# Created On Node  : glaurung.green-gryphon.com
# Last Modified By : Manoj Srivastava
# Last Modified On : Mon Apr 13 14:25:49 2009
# Last Machine Used: anzu.internal.golden-gryphon.com
# Update Count     : 59
# Status           : Unknown, Use with caution!
# HISTORY          :
# Description      :
#
#     $Id: image.postrm,v 1.31 2003/10/07 16:24:20 srivasta Exp $
#

#
#use strict; #for debugging
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');
  $capb = capb("backup");
} ## end if ( !$@ )

$| = 1;

# Predefined values:
my $version           = "=V";
my $move_image        = '';     # target machine defined
my $kimage            = "=K";   # Should be empty, mostly
my $image_dir         = "=D";   # where the image is located
my $clobber_modules   = '';     # target machine defined
my $initrd            = "=I";   # initrd kernel
my $warn_initrd       = 'YES';  # Normally we do
my $postinst_hook     = '';     #Normally we do not
my $postrm_hook       = '';     #Normally we do not
my $preinst_hook      = '';     #Normally we do not
my $prerm_hook        = '';     #Normally we do not
my $ignore_depmod_err = '';     # normally we do not
my $relink_build_link = 'YES';  # There is no harm in checking the link
my $force_build_link  = '';     # we shall not create a dangling link
my $arch              = "=A";   #  should be same as dpkg --print-architecture
my $kernel_arch       = "=B";
my $package_name       = "=ST-image-$version";
my $kernel_pkg_version = "=KPV";

#known variables
my $image_dest     = "/";
my $realimageloc   = "/$image_dir/";
my $have_conffile  = "";
my $CONF_LOC       = '/etc/kernel-img.conf';
my $silent_modules = '';
my $warn_reboot = 'Yes';        # Warn that we are installing a version of
                                # the kernel we are running

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

# remove multiple leading slashes; make sure there is at least one.
$realimageloc =~ s|^/*|/|o;
$realimageloc =~ s|/+|/|o;

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

      $move_image      = "" if m/^\s*move_image\s*=\s*(no|false|0)\s*$/i;
      $clobber_modules = '' if m/^\s*clobber_modules\s*=\s*(no|false|0)\s*$/i;
      $silent_modules  = '' if m/^\s*silent_modules\s*=\s*(no|false|0)\s*$/i;
      $warn_reboot     = '' if m/^\s*warn_reboot\s*=\s*(no|false|0)\s*$/i;
      $ignore_depmod_err = ''
        if m/^\s*ignore_depmod_err\s*=\s*(no|false|0)\s*$/i;
      $relink_src_link = '' if m/^\s*relink_src_link\s*=\s*(no|false|0)\s*$/i;
      $relink_build_link = ''
        if m/^\s*relink_build_link\s*=\s*(no|false|0)\s*$/i;
      $force_build_link = ''
        if m/^\s*force_build_link\s*=\s*(no|false|0)\s*$/i;

      $move_image = "Yes" if m/^\s*move_image\s*=\s*(yes|true|1)\s*$/i;
      $clobber_modules = "Yes"
        if m/^\s*clobber_modules\s*=\s*(yes|true|1)\s*$/i;
      $silent_modules = 'Yes'
        if m/^\s*silent_modules\s*=\s*(yes|true|1)\s*$/i;
      $warn_reboot = 'Yes' if m/^\s*warn_reboot\s*=\s*(yes|true|1)\s*$/i;
      $ignore_depmod_err = 'Yes'
        if m/^\s*ignore_depmod_err\s*=\s*(yes|true|1)\s*$/i;
      $relink_src_link = 'Yes'
        if m/^\s*relink_src_link\s*=\s*(yes|true|1)\s*$/i;
      $relink_build_link = 'Yes'
        if m/^\s*relink_build_link\s*=\s*(yes|true|1)\s*$/i;
      $force_build_link = 'Yes'
        if m/^\s*force_build_link\s*=\s*(yes|true|1)\s*$/i;

      $image_dest    = "$1" if m/^\s*image_dest\s*=\s*(\S+)/i;
      $postinst_hook = "$1" if m/^\s*postinst_hook\s*=\s*(\S+)/i;
      $postrm_hook   = "$1" if m/^\s*postrm_hook\s*=\s*(\S+)/i;
      $preinst_hook  = "$1" if m/^\s*preinst_hook\s*=\s*(\S+)/i;
      $prerm_hook    = "$1" if m/^\s*prerm_hook\s*=\s*(\S+)/i;
      $mkimage       = "$1" if m/^\s*mkimage\s*=\s*(.+)$/i;
      $ramdisk       = "$1" if m/^\s*ramdisk\s*=\s*(.+)$/i;
    } ## end while (<CONF>)
    close CONF;
    $have_conffile = "Yes";
  } ## end if ( open( CONF, "$CONF_LOC"...))
} ## end if ( -r "$CONF_LOC" &&...)

$image_dest = "$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";
}

# Paranoid check to make sure that the correct value is put in there
if ( !$kimage ) { $kimage = "vmlinuz" }    # Hmm. empty
elsif ( $kimage =~ m/^b?zImage$/o ) {
  $kimage = "vmlinuz";
}                                          # these produce vmlinuz
elsif ( $kimage =~ m/^[iI]mage$/o ) { my $nop = $kimage; }
elsif ( $kimage =~ m/^vmlinux$/o )  { my $nop = $kimage; }
elsif ( $kimage =~ m/^xen[0u]-linux$/o ) {
  $package_name = "${kimage}-$version";
}
else { $kimage = "vmlinuz" }               # default

$ENV{KERNEL_ARCH} = $kernel_arch if $kernel_arch;

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

  warn "Removing symbolic link $bad_image \n";

  # Remove the dangling link
  unlink "$bad_image";
} ## end sub remove_sym_link

######################################################################
######################################################################
############
######################################################################
######################################################################
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;
      }
    } ## end elsif ( $seg eq ".." )
    else {
      push @out, $seg;
    }
  } ## end while (@work)

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

######################################################################
######################################################################
############
######################################################################
######################################################################
# 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("$kimage");
    } ## end if ( !defined($vmlinuz_target...))
    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("$kimage");
      }
    } ## end else [ if ( !defined($vmlinuz_target...))]
  } ## end if ( -l "$kimage" )
} ## end sub image_magic

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

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", $? >> 8;
    }
  } ## end if ($?)
} ## end sub exec_script

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";
    }
  } ## end if ( $script =~ m,^/, )
  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;
      }
    } ## end for my $path ( '/bin', ...)

    # No luck
    print STDERR "Could not find $type hook script [$script].\n";
    warn "Looked in: '/bin', '/sbin', '/usr/bin', '/usr/sbin'\n";
  } ## end else [ if ( $script =~ m,^/, )]
} ## end sub run_hook

# Set up the env variable containing our arguments
my $out;
for (@ARGV) {
  s,','\\'',g;
  $out .= " '$_'";
}
$ENV{'DEB_MAINT_PARAMS'}       = "$out";
$ENV{'KERNEL_PACKAGE_VERSION'} = "$kernel_pkg_version";

if ( !$initrd ) {
  $ENV{INITRD} = 'No';
}
## Run user hook script here, if any
if ( -d "/etc/kernel/postrm.d" ) {
  warn "Examining /etc/kernel/postrm.d .\n";
  system( "run-parts --verbose --exit-on-error --arg=$version "
      . "--arg=$realimageloc$kimage-$version "
      . "/etc/kernel/postrm.d" )
    && die "Failed to process /etc/kernel/postrm.d";
} ## end if ( -d "/etc/kernel/postrm.d")
if ( -d "/etc/kernel/postrm.d/$version" ) {
  warn "Examining /etc/kernel/postrm.d/$version .\n";
  system( "run-parts --verbose --exit-on-error --arg=$version "
      . "--arg=$realimageloc$kimage-$version "
      . "/etc/kernel/postrm.d/$version" )
    && die "Failed to process /etc/kernel/postrm.d/$version";
} ## end if ( -d "/etc/kernel/postrm.d/$version")

if ($postrm_hook) {
  &run_hook( "postrm", $postrm_hook );
}

# check and remove damaged and dangling symlinks
if ( $ARGV[0] !~ /upgrade/ ) {
  image_magic( $kimage,          $image_dest );
  image_magic( $kimage . ".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 build source modules.ofmap
  modules.seriomap
};

foreach my $extra_file (@files_to_remove) {
  if ( -f "/lib/modules/$version/$extra_file" ) {
    unlink "/lib/modules/$version/$extra_file";
  }
}

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

exit 0;

__END__
