zip64 compatibility problems (original) (raw)

Martin Buchholz martinrb at google.com
Tue Jan 15 21:46:49 UTC 2013

Hi zip64 team!

It's always a problem creating zip files using new zip spec features, since older zip implementations will fail to read those files.

I see the jdk8 fix to allow the launcher to read zip64 files

changeset: 5812:f1838d040cc7 user: ksrini date: 2012-09-05 11:38 -0700 7194005: (launcher) needs to be enhanced for 64-bit jar file handling Reviewed-by: darcy, sherman

but that has not been backported to jdk7, which seems like a serious problem to me.

More generally, most zip implementations, including in the jdk, worked just fine with >64k entries, since the entry count field was generally just treated as a hint. The change to use zip64 when there are >64k entries makes zip files less portable in practice for the next few years. It would have been better to default to writing non-zip64 zip files in such cases.

Note that zip 3.0 does write zip64 files for >64k entries, but also provides a flag -fz- to change the default.

I'd like to see a backport of 7194005 and am also aware of some other issues with our ugly friend parse_manifest.c.

You changed calls to open to do this:

if ((fd = open(jarfile, O_RDONLY

#ifdef O_LARGEFILE | O_LARGEFILE /* large file mode on solaris / #endif #ifdef O_BINARY | O_BINARY / use binary mode on windows */ #endif )) == -1)

But this is not done consistently - there are 2 other calls to open in the same file that didn't get the LARGEFILE treatment. Why isn't there a JLI_Open?

Comments?

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