RFR: 8328995: launcher can't open jar files where the offset of the manifest is >4GB [v4]

[Jiangli Zhou]

On Fri, 29 Mar 2024 17:38:47 GMT, Liam Miller-Cushon <cushon at openjdk.org> wrote:

>> This change fixes a zip64 bug in the launcher that is prevent it from reading the manifest of jars where the 'relative offset of local header' field in the central directory entry is >4GB. As described in APPNOTE.TXT 4.5.3, the offset is too large to be stored in the central directory it is stored in a 'Zip64 Extended Information Extra Field'.
>
> Liam Miller-Cushon has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Maximum Zip64 extra field length is 32

src/java.base/share/native/libjli/parse_manifest.c line 506:

> 504:               jlong offset = 0;
> 505:               while (offset < cenext) {
> 506:                 short headerId = ZIPEXT_HDR(base + offset);

This block of code is very similar to the corresponding part (reading the ZIP64 extension extra fields) in `validate_lochdr`. Perhaps also refractor to a common helper function?

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PR Review Comment: https://git.openjdk.org/jdk/pull/18479#discussion_r1544754724