RFR: 5041655: (ch) FileLock: negative param and overflow issues [v3]

[Alan Bateman]

On Tue, 8 Feb 2022 20:09:10 GMT, Brian Burkhalter <bpb at openjdk.org> wrote:

> Note that because of this code in the Unix `FileDispatcherImpl.c` setting `size` to `MAX_VALUE - position` is not quite the same as what is there now:
> 
> ```
>     fl.l_whence = SEEK_SET;
>     if (size == (jlong)java_lang_Long_MAX_VALUE) {
>         fl.l_len = (off64_t)0;
>     } else {
>         fl.l_len = (off64_t)size;
>     }
> ```

There should be no impact here. If someone calls fc.lock() then it's the equivalent of fc.lock(0, MAX_VALUE, false). The FileLock will be created with size=MAX_VALUE. The code above will just map it to 0 for the call to fcntl.

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PR: https://git.openjdk.java.net/jdk/pull/7254