mkinitrd-magellan/isolinux/checksumiso.pl

#!/usr/bin/perl
#
# Construct a checksum for isolinux*.bin, compatible
# with an mkisofs boot-info-table
#

use bytes;
use integer;

($file) = @ARGV;

open(FILE, '+<', $file) or die "$0: cannot open $file: $!\n";
binmode FILE;

@fstat = stat(FILE) or die "$0: stat $file: $!\n";
if (!$fstat[7]) {
    die "$0: $file: cannot query length\n";
}

# Pad file to a multiple of 2048 bytes
$frac = $fstat[7] % 2048;
if ($frac) {
    seek(FILE,$fstat[7],0)
	or die "$0: $file: cannot seek to end\n";
    print FILE "\0" x (2048-$frac);
}

# Checksum the file post header
if ( !seek(FILE,64,0) ) {
    die "$0: $file: cannot seek past header\n";
}

$csum  = 0;
$bytes = 64;
while ( ($n = read(FILE, $dw, 4)) > 0 ) {
    $dw .= "\0\0\0\0";		# Pad to at least 32 bits
    ($v) = unpack("V", $dw);
    $csum  = ($csum + $v) & 0xffffffff;
    $bytes += $n;
}

# Update header
if ( !seek(FILE,16,0) ) {
    die "$0: $file: cannot seek to header\n";
}

print FILE pack("VV", $bytes, $csum);

close(FILE);

exit 0;
1	niro	532	#!/usr/bin/perl
2			#
3			# Construct a checksum for isolinux*.bin, compatible
4			# with an mkisofs boot-info-table
5			#
6
7			use bytes;
8			use integer;
9
10			($file) = @ARGV;
11
12	niro	1133	open(FILE, '+<', $file) or die "$0: cannot open $file: $!\n";
13	niro	532	binmode FILE;
14
15	niro	1133	@fstat = stat(FILE) or die "$0: stat $file: $!\n";
16			if (!$fstat[7]) {
17			die "$0: $file: cannot query length\n";
18			}
19
20			# Pad file to a multiple of 2048 bytes
21			$frac = $fstat[7] % 2048;
22			if ($frac) {
23			seek(FILE,$fstat[7],0)
24			or die "$0: $file: cannot seek to end\n";
25			print FILE "\0" x (2048-$frac);
26			}
27
28			# Checksum the file post header
29	niro	532	if ( !seek(FILE,64,0) ) {
30	niro	1133	die "$0: $file: cannot seek past header\n";
31	niro	532	}
32
33			$csum = 0;
34			$bytes = 64;
35			while ( ($n = read(FILE, $dw, 4)) > 0 ) {
36			$dw .= "\0\0\0\0"; # Pad to at least 32 bits
37			($v) = unpack("V", $dw);
38			$csum = ($csum + $v) & 0xffffffff;
39			$bytes += $n;
40			}
41
42	niro	1133	# Update header
43	niro	532	if ( !seek(FILE,16,0) ) {
44	niro	1133	die "$0: $file: cannot seek to header\n";
45	niro	532	}
46
47			print FILE pack("VV", $bytes, $csum);
48
49			close(FILE);
50
51			exit 0;