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Re: fork/exec & close file descriptors

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Marko Rauhamaa <marko@pacujo.net> writes:

> Alain Ketterlin <alain@universite-de-strasbourg.fr.invalid>:
>
>> Marko Rauhamaa <marko@pacujo.net> writes:
>>> First, if close() fails, what's a poor program to do?
>>
>> Warn the user? Not assume everything went well? It all depends on the
>> application, and what the file descriptor represents.
>
> The problem here is in the system call contract, which is broken.
> There's no fix. The man page admonition is just hand-waving without
> constructive advice.
>
>>> Try again?
>> Could be a good idea on NFS or other kind of mounts.
>
> Maybe close() will fail for ever.

Your program has to deal with this, something is going wrong, it can't
just close and go on.

>> I can't imagine why one would like to mass-close an arbitrary set of
>> file descriptors,
>
> That's standard practice before execking a file. [...]

>> and I think APIs like os.closerange() are toxic and an appeal to
>> sloppy programming.
>
> And you recommend what instead?

Keeping them around and closing the ones you own, plus doing whatever is
necessary to have libraires (loggers, database connectors, etc.) finish
properly. And not taking the risk of messing with descriptors your
program is not responsible of.

-- Alain.

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Re: fork/exec & close file descriptors Skip Montanaro <skip.montanaro@gmail.com> - 2015-06-02 08:58 -0500
  Re: fork/exec & close file descriptors Marko Rauhamaa <marko@pacujo.net> - 2015-06-02 18:28 +0300
    Re: fork/exec & close file descriptors Skip Montanaro <skip.montanaro@gmail.com> - 2015-06-02 10:42 -0500
      Re: fork/exec & close file descriptors Marko Rauhamaa <marko@pacujo.net> - 2015-06-02 19:24 +0300
        Re: fork/exec & close file descriptors Jon Ribbens <jon+usenet@unequivocal.co.uk> - 2015-06-02 16:37 +0000
    Re: fork/exec & close file descriptors MrJean1 <MrJean1@gmail.com> - 2015-06-12 13:43 -0700
  Re: fork/exec & close file descriptors Alain Ketterlin <alain@universite-de-strasbourg.fr.invalid> - 2015-06-02 17:59 +0200
    Re: fork/exec & close file descriptors Marko Rauhamaa <marko@pacujo.net> - 2015-06-02 23:05 +0300
      Re: fork/exec & close file descriptors Alain Ketterlin <alain@universite-de-strasbourg.fr.invalid> - 2015-06-02 23:06 +0200
        Re: fork/exec & close file descriptors Marko Rauhamaa <marko@pacujo.net> - 2015-06-03 01:24 +0300
          Re: fork/exec & close file descriptors Alain Ketterlin <alain@universite-de-strasbourg.fr.invalid> - 2015-06-03 09:21 +0200
            Re: fork/exec & close file descriptors Marko Rauhamaa <marko@pacujo.net> - 2015-06-03 10:41 +0300
              Re: fork/exec & close file descriptors alister <alister.nospam.ware@ntlworld.com> - 2015-06-03 09:38 +0000
                Re: fork/exec & close file descriptors Steven D'Aprano <steve@pearwood.info> - 2015-06-03 22:07 +1000
                Re: fork/exec & close file descriptors alister <alister.nospam.ware@ntlworld.com> - 2015-06-03 12:18 +0000
                Re: fork/exec & close file descriptors Marko Rauhamaa <marko@pacujo.net> - 2015-06-03 15:27 +0300
                Re: fork/exec & close file descriptors alister <alister.nospam.ware@ntlworld.com> - 2015-06-03 13:05 +0000
                Re: fork/exec & close file descriptors Marko Rauhamaa <marko@pacujo.net> - 2015-06-03 17:49 +0300
                Re: fork/exec & close file descriptors Marko Rauhamaa <marko@pacujo.net> - 2015-06-03 15:25 +0300
                Re: fork/exec & close file descriptors random832@fastmail.us - 2015-06-03 08:54 -0400
                Re: fork/exec & close file descriptors Marko Rauhamaa <marko@pacujo.net> - 2015-06-03 16:08 +0300
                Re: fork/exec & close file descriptors random832@fastmail.us - 2015-06-03 09:21 -0400
                Re: fork/exec & close file descriptors Chris Angelico <rosuav@gmail.com> - 2015-06-03 23:32 +1000
                Re: fork/exec & close file descriptors Marko Rauhamaa <marko@pacujo.net> - 2015-06-03 16:33 +0300
                Re: fork/exec & close file descriptors Marko Rauhamaa <marko@pacujo.net> - 2015-06-03 17:43 +0300
                Re: fork/exec & close file descriptors random832@fastmail.us - 2015-06-03 16:08 -0400
                Re: fork/exec & close file descriptors Marko Rauhamaa <marko@pacujo.net> - 2015-06-04 00:09 +0300
                Re: fork/exec & close file descriptors random832@fastmail.us - 2015-06-03 16:07 -0400
                Re: fork/exec & close file descriptors Chris Angelico <rosuav@gmail.com> - 2015-06-04 07:54 +1000
        Re: fork/exec & close file descriptors Chris Angelico <rosuav@gmail.com> - 2015-06-03 09:54 +1000
          Re: fork/exec & close file descriptors Alain Ketterlin <alain@universite-de-strasbourg.fr.invalid> - 2015-06-03 09:11 +0200
            Re: fork/exec & close file descriptors random832@fastmail.us - 2015-06-03 08:21 -0400
              Re: fork/exec & close file descriptors Alain Ketterlin <alain@universite-de-strasbourg.fr.invalid> - 2015-06-03 15:16 +0200
        Re: fork/exec & close file descriptors Skip Montanaro <skip.montanaro@gmail.com> - 2015-06-02 20:21 -0500

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