Fix two separate El Torito bugs. - #183
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1. The OpenBSD ISO apparently uses 0xdf instead of 0x00 for padding, which means our earlier heuristic for determining the end of the El Torito section (used for FreeBSD) didn't work there. Now we instead make sure that the number of sections equals the number we were told at the beginning, ignoring the padding. That makes it work for both, even in the absence of a proper terminator. 2. Running "genisoimage -no-boot" created an ISO that we couldn't parse because it added in 0x00 in the list, and 0x00 was being handled up-front so could never be hit later. 0x0 is unfortunately ambiguous; it means both non-bootable entry and terminator simultaneously, so we have to use context to figure out which one we should do. If the last section header still needs an entry, and the record has non-zero content, we treat it as a non-bootable entry. Otherwise we treat it as the terminator. Signed-off-by: Chris Lalancette <clalancette@gmail.com>
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The OpenBSD ISO apparently uses 0xdf instead of 0x00 for padding, which means our earlier heuristic for determining the end of the El Torito section (used for FreeBSD) didn't work there. Now we instead make sure that the number of sections equals the number we were told at the beginning, ignoring the padding. That makes it work for both, even in the absence of a proper terminator.
Running "genisoimage -no-boot" created an ISO that we couldn't parse because it added in 0x00 in the list, and 0x00 was being handled up-front so could never be hit later. 0x0 is unfortunately ambiguous; it means both non-bootable entry and terminator simultaneously, so we have to use context to figure out which one we should do. If the last section header still needs an entry, and the record has non-zero content, we treat it as a non-bootable entry. Otherwise we treat it as the terminator.
This fixes #180