New submission from Alexey Izbyshev <izbys...@ispras.ru>:
Demonstration:
$ cat test.py
import os
import subprocess
import sys
fd = os.dup(sys.stdout.fileno())
subprocess.call([sys.executable, '-c',
'import sys;'
'print("Hello stdout");'
'print("Hello fd", file=open(int(sys.argv[1]), "w"))',
str(fd)],
stdout=fd,
pass_fds=[fd])
$ python3 test.py
Hello stdout
Traceback (most recent call last):
File "<string>", line 1, in <module>
OSError: [Errno 9] Bad file descriptor
I see two issues here:
1. The fact that file descriptors specified for redirection are closed (even
with close_fds=False) unless in range [0, 2] is not documented and not tested.
If I change the corresponding code in _posixsubprocess.c to close them only if
they are ends of pipes created by subprocess itself, all tests still pass.
Also, shells behave differently: e.g., in command 'echo 3>&1' fd 3 is
duplicated but not closed in the child, so subprocess behavior may be not what
people expect.
2. pass_fds interaction with (1) should be fixed and documented. We may either
raise ValueError if pass_fds contains a redirected fd or don't close such a
redirected fd.
Please provide your thoughts.
----------
components: Library (Lib)
files: test.py
messages: 307962
nosy: gregory.p.smith, izbyshev, pitrou, vstinner
priority: normal
severity: normal
status: open
title: subprocess closes redirected fds even if they are in pass_fds
type: behavior
versions: Python 3.6, Python 3.7
Added file: https://bugs.python.org/file47329/test.py
_______________________________________
Python tracker <rep...@bugs.python.org>
<https://bugs.python.org/issue32270>
_______________________________________
_______________________________________________
Python-bugs-list mailing list
Unsubscribe:
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
