[util] Add Option::ROM library and rewrite disrom.pl to use it.

The Option::ROM module provides an easy way to read and edit fields
within option ROM headers.

1 files changed, 459 insertions, 0 deletions

diff --git a/src/util/Option/ROM.pm b/src/util/Option/ROM.pm
new file mode 100644
index 00000000..f5c33f8a
--- /dev/null
+++ b/src/util/Option/ROM.pm
@@ -0,0 +1,459 @@
+package Option::ROM;
+
+# Copyright (C) 2008 Michael Brown <mbrown@fensystems.co.uk>.
+#
+# 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; either version 2 of the
+# License, or any later version.
+#
+# 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., 675 Mass Ave, Cambridge, MA 02139, USA.
+
+=head1 NAME
+
+Option::ROM - Option ROM manipulation
+
+=head1 SYNOPSIS
+
+    use Option::ROM;
+
+    # Load a ROM image
+    my $rom = new Option::ROM;
+    $rom->load ( "rtl8139.rom" );
+
+    # Modify the PCI device ID
+    $rom->pci_header->{device_id} = 0x1234;
+    $rom->fix_checksum();
+
+    # Write ROM image out to a new file
+    $rom->save ( "rtl8139-modified.rom" );
+
+=head1 DESCRIPTION
+
+C<Option::ROM> provides a mechanism for manipulating Option ROM
+images.
+
+=head1 METHODS
+
+=cut
+
+##############################################################################
+#
+# Option::ROM::Fields
+#
+##############################################################################
+
+package Option::ROM::Fields;
+
+use strict;
+use warnings;
+use Carp;
+use bytes;
+
+sub TIEHASH {
+  my $class = shift;
+  my $self = shift;
+
+  bless $self, $class;
+  return $self;
+}
+
+sub FETCH {
+  my $self = shift;
+  my $key = shift;
+
+  return undef unless $self->EXISTS ( $key );
+  my $raw = substr ( ${$self->{data}},
+		     ( $self->{offset} + $self->{fields}->{$key}->{offset} ),
+		     $self->{fields}->{$key}->{length} );
+  return unpack ( $self->{fields}->{$key}->{pack}, $raw );
+}
+
+sub STORE {
+  my $self = shift;
+  my $key = shift;
+  my $value = shift;
+
+  croak "Nonexistent field \"$key\"" unless $self->EXISTS ( $key );
+  my $raw = pack ( $self->{fields}->{$key}->{pack}, $value );
+  substr ( ${$self->{data}},
+	   ( $self->{offset} + $self->{fields}->{$key}->{offset} ),
+	   $self->{fields}->{$key}->{length} ) = $raw;
+}
+
+sub DELETE {
+  my $self = shift;
+  my $key = shift;
+
+  $self->STORE ( $key, 0 );
+}
+
+sub CLEAR {
+  my $self = shift;
+
+  foreach my $key ( keys %{$self->{fields}} ) {
+    $self->DELETE ( $key );
+  }
+}
+
+sub EXISTS {
+  my $self = shift;
+  my $key = shift;
+
+  return ( exists $self->{fields}->{$key} &&
+	   ( ( $self->{fields}->{$key}->{offset} +
+	       $self->{fields}->{$key}->{length} ) <= $self->{length} ) );
+}
+
+sub FIRSTKEY {
+  my $self = shift;
+
+  keys %{$self->{fields}};
+  return each %{$self->{fields}};
+}
+
+sub NEXTKEY {
+  my $self = shift;
+  my $lastkey = shift;
+
+  return each %{$self->{fields}};
+}
+
+sub SCALAR {
+  my $self = shift;
+
+  return 1;
+}
+
+sub UNTIE {
+  my $self = shift;
+}
+
+sub DESTROY {
+  my $self = shift;
+}
+
+sub checksum {
+  my $self = shift;
+
+  my $raw = substr ( ${$self->{data}}, $self->{offset}, $self->{length} );
+  return unpack ( "%8C*", $raw );
+}
+
+##############################################################################
+#
+# Option::ROM
+#
+##############################################################################
+
+package Option::ROM;
+
+use strict;
+use warnings;
+use Carp;
+use bytes;
+use Exporter 'import';
+
+use constant ROM_SIGNATURE => 0xaa55;
+use constant PCI_SIGNATURE => 'PCIR';
+use constant PNP_SIGNATURE => '$PnP';
+
+our @EXPORT_OK = qw ( ROM_SIGNATURE PCI_SIGNATURE PNP_SIGNATURE );
+our %EXPORT_TAGS = ( all => [ @EXPORT_OK ] );
+
+=pod
+
+=item C<< new () >>
+
+Construct a new C<Option::ROM> object.
+
+=cut
+
+sub new {
+  my $class = shift;
+
+  my $hash = {};
+  tie %$hash, "Option::ROM::Fields", {
+    data => undef,
+    offset => 0x00,
+    length => 0x20,
+    fields => {
+      signature =>	{ offset => 0x00, length => 0x02, pack => "S" },
+      length =>		{ offset => 0x02, length => 0x01, pack => "C" },
+      checksum =>	{ offset => 0x06, length => 0x01, pack => "C" },
+      undi_header =>	{ offset => 0x16, length => 0x02, pack => "S" },
+      pci_header =>	{ offset => 0x18, length => 0x02, pack => "S" },
+      pnp_header =>	{ offset => 0x1a, length => 0x02, pack => "S" },
+    },
+  };
+  bless $hash, $class;
+  return $hash;
+}
+
+=pod
+
+=item C<< load ( $filename ) >>
+
+Load option ROM contents from the file C<$filename>.
+
+=cut
+
+sub load {
+  my $hash = shift;
+  my $self = tied(%$hash);
+  my $filename = shift;
+
+  $self->{filename} = $filename;
+
+  open my $fh, "<$filename"
+      or croak "Cannot open $filename for reading: $!";
+  read $fh, my $data, ( 128 * 1024 ); # 128kB is theoretical max size
+  $self->{data} = \$data;
+  close $fh;
+}
+
+=pod
+
+=item C<< save ( [ $filename ] ) >>
+
+Write the ROM data back out to the file C<$filename>.  If C<$filename>
+is omitted, the file used in the call to C<load()> will be used.
+
+=cut
+
+sub save {
+  my $hash = shift;
+  my $self = tied(%$hash);
+  my $filename = shift;
+
+  $filename ||= $self->{filename};
+
+  open my $fh, ">$filename"
+      or croak "Cannot open $filename for writing: $!";
+  print $fh ${$self->{data}};
+  close $fh;
+}
+
+=pod
+
+=item C<< length () >>
+
+Length of option ROM data.  This is the length of the file, not the
+length from the ROM header length field.
+
+=cut
+
+sub length {
+  my $hash = shift;
+  my $self = tied(%$hash);
+
+  return length ${$self->{data}};
+}
+
+=pod
+
+=item C<< pci_header () >>
+
+Return a C<Option::ROM::PCI> object representing the ROM's PCI header,
+if present.
+
+=cut
+
+sub pci_header {
+  my $hash = shift;
+  my $self = tied(%$hash);
+
+  my $offset = $hash->{pci_header};
+  return undef unless $offset != 0;
+
+  return Option::ROM::PCI->new ( $self->{data}, $offset );
+}
+
+=pod
+
+=item C<< pnp_header () >>
+
+Return a C<Option::ROM::PnP> object representing the ROM's PnP header,
+if present.
+
+=cut
+
+sub pnp_header {
+  my $hash = shift;
+  my $self = tied(%$hash);
+
+  my $offset = $hash->{pnp_header};
+  return undef unless $offset != 0;
+
+  return Option::ROM::PnP->new ( $self->{data}, $offset );
+}
+
+=pod
+
+=item C<< checksum () >>
+
+Calculate the byte checksum of the ROM.
+
+=cut
+
+sub checksum {
+  my $hash = shift;
+  my $self = tied(%$hash);
+
+  return unpack ( "%8C*", ${$self->{data}} );
+}
+
+=pod
+
+=item C<< fix_checksum () >>
+
+Fix the byte checksum of the ROM.
+
+=cut
+
+sub fix_checksum {
+  my $hash = shift;
+  my $self = tied(%$hash);
+
+  $hash->{checksum} = ( ( $hash->{checksum} - $hash->checksum() ) & 0xff );
+}
+
+##############################################################################
+#
+# Option::ROM::PCI
+#
+##############################################################################
+
+package Option::ROM::PCI;
+
+use strict;
+use warnings;
+use Carp;
+use bytes;
+
+sub new {
+  my $class = shift;
+  my $data = shift;
+  my $offset = shift;
+
+  my $hash = {};
+  tie %$hash, "Option::ROM::Fields", {
+    data => $data,
+    offset => $offset,
+    length => 0x0c,
+    fields => {
+      signature =>	{ offset => 0x00, length => 0x04, pack => "a4" },
+      vendor_id =>	{ offset => 0x04, length => 0x02, pack => "S" },
+      device_id =>	{ offset => 0x06, length => 0x02, pack => "S" },
+      device_list =>	{ offset => 0x08, length => 0x02, pack => "S" },
+      struct_length =>	{ offset => 0x0a, length => 0x02, pack => "S" },
+      struct_revision =>{ offset => 0x0c, length => 0x01, pack => "C" },
+      base_class => 	{ offset => 0x0d, length => 0x01, pack => "C" },
+      sub_class => 	{ offset => 0x0e, length => 0x01, pack => "C" },
+      prog_intf => 	{ offset => 0x0f, length => 0x01, pack => "C" },
+      image_length =>	{ offset => 0x10, length => 0x02, pack => "S" },
+      revision =>	{ offset => 0x12, length => 0x02, pack => "S" },
+      code_type => 	{ offset => 0x14, length => 0x01, pack => "C" },
+      last_image => 	{ offset => 0x15, length => 0x01, pack => "C" },
+      runtime_length =>	{ offset => 0x16, length => 0x02, pack => "S" },
+      conf_header =>	{ offset => 0x18, length => 0x02, pack => "S" },
+      clp_entry =>	{ offset => 0x1a, length => 0x02, pack => "S" },
+    },
+  };
+  bless $hash, $class;
+
+  # Retrieve true length of structure
+  my $self = tied ( %$hash );
+  $self->{length} = $hash->{struct_length};
+
+  return $hash;  
+}
+
+##############################################################################
+#
+# Option::ROM::PnP
+#
+##############################################################################
+
+package Option::ROM::PnP;
+
+use strict;
+use warnings;
+use Carp;
+use bytes;
+
+sub new {
+  my $class = shift;
+  my $data = shift;
+  my $offset = shift;
+
+  my $hash = {};
+  tie %$hash, "Option::ROM::Fields", {
+    data => $data,
+    offset => $offset,
+    length => 0x06,
+    fields => {
+      signature =>	{ offset => 0x00, length => 0x04, pack => "a4" },
+      struct_revision =>{ offset => 0x04, length => 0x01, pack => "C" },
+      struct_length =>	{ offset => 0x05, length => 0x01, pack => "C" },
+      checksum =>	{ offset => 0x09, length => 0x01, pack => "C" },
+      manufacturer =>	{ offset => 0x0e, length => 0x02, pack => "S" },
+      product =>	{ offset => 0x10, length => 0x02, pack => "S" },
+      bcv =>		{ offset => 0x16, length => 0x02, pack => "S" },
+      bdv =>		{ offset => 0x18, length => 0x02, pack => "S" },
+      bev =>		{ offset => 0x1a, length => 0x02, pack => "S" },
+    },
+  };
+  bless $hash, $class;
+
+  # Retrieve true length of structure
+  my $self = tied ( %$hash );
+  $self->{length} = ( $hash->{struct_length} * 16 );
+
+  return $hash;  
+}
+
+sub checksum {
+  my $hash = shift;
+  my $self = tied(%$hash);
+
+  return $self->checksum();
+}
+
+sub fix_checksum {
+  my $hash = shift;
+  my $self = tied(%$hash);
+
+  $hash->{checksum} = ( ( $hash->{checksum} - $hash->checksum() ) & 0xff );
+}
+
+sub manufacturer {
+  my $hash = shift;
+  my $self = tied(%$hash);
+
+  my $manufacturer = $hash->{manufacturer};
+  return undef unless $manufacturer;
+
+  my $raw = substr ( ${$self->{data}}, $manufacturer );
+  return unpack ( "Z*", $raw );
+}
+
+sub product {
+  my $hash = shift;
+  my $self = tied(%$hash);
+
+  my $product = $hash->{product};
+  return undef unless $product;
+
+  my $raw = substr ( ${$self->{data}}, $product );
+  return unpack ( "Z*", $raw );
+}
+
+1;