RFR: 8271003: hs_err improvement: handle CLASSPATH env setting longer than O_BUFLEN [v2]

[David Holmes]

On Tue, 3 Aug 2021 16:14:57 GMT, Calvin Cheung <ccheung at openjdk.org> wrote:

>> Please review this small enhancement for addressing the problem of the CLASSPATH env variable setting being truncated in a hs err log.
>> 
>> For printing a char string, it doesn't need to go through `do_vsnprintf()` which does the truncation based on the input buffer length. The change is local to the code path pertaining to hs err log.
>> 
>> Testing:
>> 
>> - [x] tiers 1, 2 (including the new test)
>
> Calvin Cheung has updated the pull request incrementally with one additional commit since the last revision:
> 
>   @tstuefe comments

Looks good.

One comment request.

Thanks,
David

src/hotspot/share/runtime/os.cpp line 992:

> 990:         st->print("%s", env_list[i]);
> 991:         st->print("=");
> 992:         st->print("%s", envvar);

I suggest adding a comment like:
// Use separate cr() printing to avoid unnecessary buffer operations that might cause truncation

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Marked as reviewed by dholmes (Reviewer).

PR: https://git.openjdk.java.net/jdk/pull/4947