37 lines
634 B
Perl
Executable File
37 lines
634 B
Perl
Executable File
#!/usr/bin/perl
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#
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# Construct a checksum for isolinux*.bin, compatible
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# with an mkisofs boot-info-table
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#
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use bytes;
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use integer;
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($file) = @ARGV;
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open(FILE, '+<', $file) or die "$0: Cannot open $file: $!\n";
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binmode FILE;
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if ( !seek(FILE,64,0) ) {
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die "$0: Cannot seek past header\n";
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}
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$csum = 0;
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$bytes = 64;
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while ( ($n = read(FILE, $dw, 4)) > 0 ) {
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$dw .= "\0\0\0\0"; # Pad to at least 32 bits
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($v) = unpack("V", $dw);
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$csum = ($csum + $v) & 0xffffffff;
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$bytes += $n;
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}
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if ( !seek(FILE,16,0) ) {
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die "$0: Cannot seek to header\n";
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}
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print FILE pack("VV", $bytes, $csum);
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close(FILE);
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exit 0;
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