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Date: Tue, 19 May 2015 23:54:37 +1000
Subject: Re: fork/exec & close file descriptors
From: Chris Angelico <rosuav@gmail.com>
Cc: Python <python-list@python.org>
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On Tue, May 19, 2015 at 11:44 PM, Skip Montanaro
<skip.montanaro@gmail.com> wrote:
>
> On Tue, May 19, 2015 at 8:33 AM, Chris Angelico <rosuav@gmail.com> wrote:
>>
>> What Python version are you targeting? Are you aware of PEP 446?
>
>
> Yeah, I'm still on 2.7, and am aware of PEP 446. Note that many of the file
> descriptors will not have been created by my Python code. They will have
> been created by underlying C/C++ libraries, so I can't guarantee which flags
> were set on file open.
>
> I'm going to continue to pursue solutions which won't require a restart for
> now, but would like to have a sane restart option in my back pocket should
> it become necessary.

Fair enough. What you MAY be able to do is preempt it by going through
your FDs and setting them all CLOEXEC, but it won't make a lot of
difference compared to just going through them all and closing them
between fork and exec.

On Linux (and possibly some other Unixes), /proc/self/fd may be of
use. Enumerating files in that should tell you about your open files.
How useful that is I don't know, though.

ChrisA