[Python-checkins] cpython: Issue #21515: tempfile.TemporaryFile now uses os.O_TMPFILE flag is available

Thu Jun 5 14:29:34 CEST 2014

http://hg.python.org/cpython/rev/4b51a992cb70
changeset: 91033:4b51a992cb70
user: Victor Stinner <victor.stinner at gmail.com>
date: Thu Jun 05 14:27:45 2014 +0200
summary:
 Issue #21515: tempfile.TemporaryFile now uses os.O_TMPFILE flag is available
files:
 Doc/library/tempfile.rst | 7 +++++++
 Lib/tempfile.py | 26 ++++++++++++++++++++++++++
 Misc/NEWS | 2 ++
 3 files changed, 35 insertions(+), 0 deletions(-)

diff --git a/Doc/library/tempfile.rst b/Doc/library/tempfile.rst
--- a/Doc/library/tempfile.rst
+++ b/Doc/library/tempfile.rst
@@ -54,6 +54,13 @@
 underlying true file object. This file-like object can be used in a
 :keyword:`with` statement, just like a normal file.
 
+ The :py:data:`os.O_TMPFILE` flag is used if it is available and works
+ (Linux-specific, require Linux kernel 3.11 or later).
+
+ .. versionchanged:: 3.5
+
+ The :py:data:`os.O_TMPFILE` flag is now used if available.
+
 
 .. function:: NamedTemporaryFile(mode='w+b', buffering=None, encoding=None, newline=None, suffix='', prefix='tmp', dir=None, delete=True)
 
diff --git a/Lib/tempfile.py b/Lib/tempfile.py
--- a/Lib/tempfile.py
+++ b/Lib/tempfile.py
@@ -473,6 +473,11 @@
 TemporaryFile = NamedTemporaryFile
 
 else:
+ # Is the O_TMPFILE flag available and does it work?
+ # The flag is set to False if os.open(dir, os.O_TMPFILE) raises an
+ # IsADirectoryError exception
+ _O_TMPFILE_WORKS = hasattr(_os, 'O_TMPFILE')
+
 def TemporaryFile(mode='w+b', buffering=-1, encoding=None,
 newline=None, suffix="", prefix=template,
 dir=None):
@@ -488,11 +493,32 @@
 Returns an object with a file-like interface. The file has no
 name, and will cease to exist when it is closed.
 """
+ global _O_TMPFILE_WORKS
 
 if dir is None:
 dir = gettempdir()
 
 flags = _bin_openflags
+ if _O_TMPFILE_WORKS:
+ try:
+ flags2 = (flags | _os.O_TMPFILE) & ~_os.O_CREAT
+ fd = _os.open(dir, flags2, 0o600)
+ except IsADirectoryError:
+ # Linux kernel older than 3.11 ignores O_TMPFILE flag.
+ # Set flag to None to not try again.
+ _O_TMPFILE_WORKS = False
+ except OSError:
+ # The filesystem of the directory does not support O_TMPFILE.
+ # For example, OSError(95, 'Operation not supported').
+ pass
+ else:
+ try:
+ return _io.open(fd, mode, buffering=buffering,
+ newline=newline, encoding=encoding)
+ except:
+ _os.close(fd)
+ raise
+ # Fallback to _mkstemp_inner().
 
 (fd, name) = _mkstemp_inner(dir, prefix, suffix, flags)
 try:
diff --git a/Misc/NEWS b/Misc/NEWS
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -88,6 +88,8 @@
 Library
 -------
 
+- Issue #21515: tempfile.TemporaryFile now uses os.O_TMPFILE flag is available.
+
 - Issue #21618: The subprocess module could fail to close open fds that were
 inherited by the calling process and already higher than POSIX resource
 limits would otherwise allow. On systems with a functioning /proc/self/fd
-- 
Repository URL: http://hg.python.org/cpython
