[New-bugs-announce] [issue21058] tempfile.NamedTemporaryFile leaks file descriptor when fdopen fails

[tholzer]

New submission from tholzer:

The NamedTemporaryFile inside the standard tempfile library leaks an open file descriptor when fdopen fails.

Test case:

# ulimit -SHn 50
# python test1.py

from tempfile import NamedTemporaryFile

while 1:
    try:
        NamedTemporaryFile(mode='x')
    except ValueError as ex:
        pass

Output:

Traceback (most recent call last):
  File "./a2.py", line 7, in <module>
  File "/usr/lib/python2.7/tempfile.py", line 454, in NamedTemporaryFile
  File "/usr/lib/python2.7/tempfile.py", line 235, in _mkstemp_inner
OSError: [Errno 24] Too many open files: '/tmp/tmpI0MIEW'
Error in sys.excepthook:
Traceback (most recent call last):
  File "/usr/lib/python2.7/dist-packages/apport_python_hook.py", line 66, in apport_excepthook
ImportError: No module named fileutils

Original exception was:
Traceback (most recent call last):
  File "./a2.py", line 7, in <module>
  File "/usr/lib/python2.7/tempfile.py", line 454, in NamedTemporaryFile
  File "/usr/lib/python2.7/tempfile.py", line 235, in _mkstemp_inner
OSError: [Errno 24] Too many open files: '/tmp/tmpI0MIEW'

Patch:

@@ -452,7 +452,11 @@
         flags |= _os.O_TEMPORARY
 
     (fd, name) = _mkstemp_inner(dir, prefix, suffix, flags)
-    file = _os.fdopen(fd, mode, bufsize)
+    try:
+        file = _os.fdopen(fd, mode, bufsize)
+    except Exception as ex:
+        _os.close(fd)
+        raise
     return _TemporaryFileWrapper(file, name, delete)
 
 if _os.name != 'posix' or _os.sys.platform == 'cygwin':

----------
components: Library (Lib)
messages: 214778
nosy: tholzer
priority: normal
severity: normal
status: open
title: tempfile.NamedTemporaryFile leaks file descriptor when fdopen fails
type: resource usage
versions: Python 2.7

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Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue21058>
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