[Python-Dev] PEP 446: Open issues/questions (original) (raw)

Antoine Pitrou solipsis at pitrou.net
Mon Jul 29 23:49:49 CEST 2013

On Mon, 29 Jul 2013 23:42:36 +0200 Victor Stinner <victor.stinner at gmail.com> wrote:

>> So perhaps only the original standard streams should be left >> inheritable? I plan to only change functions creating (and replacing) new file descriptors. Existing file descriptors (like 0, 1, 2) are unchanged.

You can create fds 0, 1 and 2 if they were closed before.

> Having stdin/stdout/stderr cloexec (e.g. after a dup() to redirect to > a log file, a socket...) will likely break a lot of code, e.g. code > using os.system(), or code calling exec manually (and I'm sure there's > a bunch of it).

I propose to add just one special case os.dup2(fd, fd2): if fd2 < 3, fd2 is set to inheritable (otherwise, fd2 is set to non-inheritable). os.dup2() is commonly used to replace stdin, stdout and stderr between fork and exec. The http.server (cgi server) and pty modules use dup2() for example

Mmh. Doing it only in dup2() sounds like too much special casing for me. I would prefer adding a new explicit parameter: os.dup2(fd, fd2, inheritable=False)

(as a bonus, it can be implemented using dup3() under (GNU/)Linux)

Regards

Antoine.

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