[process] Include process name in debug messages
[ipxe.git] / src / util / swapdevids.pl
1 #!/usr/bin/perl -w
2 #
3 # Program to reverse the device identifier IDs in the PCIR and PnP
4 # structures in a ROM for old non-compliant BIOSes
5 #
6 # GPL, Ken Yap 2001
7 #
8
9 use bytes;
10
11 use IO::Seekable;
12
13 sub swaplocs ($$$)
14 {
15 my ($dataref, $loc1, $loc2) = @_;
16 my ($t);
17
18 $t = substr($$dataref, $loc1, 1);
19 substr($$dataref, $loc1, 1) = substr($$dataref, $loc2, 1);
20 substr($$dataref, $loc2, 1) = $t;
21 }
22
23 sub printdevids ($$)
24 {
25 my ($dataref, $loc) = @_;
26
27 return (sprintf "%02x %02x %02x", unpack('C3', substr($$dataref, $loc, 3)));
28 }
29
30 $#ARGV >= 0 or die "Usage: $0 romimage\n";
31 $file = $ARGV[0];
32 open(F, "+<$file") or die "$file: $!\n";
33 binmode(F);
34 # Handle up to 64kB ROM images
35 $len = read(F, $data, 64*1024);
36 defined($len) or die "$file: $!\n";
37 substr($data, 0, 2) eq "\x55\xAA" or die "$file: Not a boot ROM image\n";
38 ($pci, $pnp) = unpack('v2', substr($data, 0x18, 4));
39 ($pci < $len and $pnp < $len) or die "$file: Not a PCI PnP ROM image\n";
40 (substr($data, $pci, 4) eq 'PCIR' and substr($data, $pnp, 4) eq '$PnP')
41 or die "$file: No PCI and PNP structures, not a PCI PNP ROM image\n";
42 &swaplocs(\$data, $pci+13, $pci+15);
43 &swaplocs(\$data, $pnp+18, $pnp+20);
44 seek(F, 0, SEEK_SET) or die "$file: Cannot seek to beginning\n";
45 print F $data;
46 close(F);
47 print "PCI devids now: ", &printdevids(\$data, $pci+13), "\n";
48 print "PnP devids now: ", &printdevids(\$data, $pnp+18), "\n";
49 exit(0);