RFR: 8291067: macOS should use O_CLOEXEC instead of FD_CLOEXEC [v2]

[Thomas Stuefe]

On Wed, 28 Sep 2022 17:21:53 GMT, Gerard Ziemski <gziemski at openjdk.org> wrote:

>> O_CLOEXEC is also available on macOS (__DARWIN_C_LEVEL >= 200809L), so use it same as on linux.
>
> Gerard Ziemski has updated the pull request incrementally with two additional commits since the last revision:
> 
>  - add test to verify that open(O_CLOEXEC) implies FD_CLOEXEC on macOS
>  - assume O_CLOEXEC on macOS

Some small remarks inline, otherwise this looks ok

src/hotspot/os/bsd/os_bsd.cpp line 2214:

> 2212:   // O_CLOEXEC is preferable to using FD_CLOEXEC on an open file descriptor
> 2213:   // because it saves a system call and removes a small window where the flag
> 2214:   // is unset.

I'm not even sure this comment is useful. Your code is clear and obvious. Discussing an alternate route may be confusing if people don't know the history if this code.

src/hotspot/os/bsd/os_bsd.cpp line 2215:

> 2213:   // because it saves a system call and removes a small window where the flag
> 2214:   // is unset.
> 2215:   int fd = ::open(path, oflag|O_CLOEXEC, mode);

Style nit: should there be spaces between |?

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PR: https://git.openjdk.org/jdk/pull/9663