pythongh-136156: Allow using linkat() with TemporaryFile

vstinner · vstinner · commit 97c3d25e3049 · 2025-07-04T12:54:18.000+02:00
tempfile.TemporaryFile() no longer uses os.O_EXCL with os.O_TMPFILE,
so it's possible to use linkat() on the file descriptor.
diff --git a/Lib/tempfile.py b/Lib/tempfile.py
@@ -656,7 +656,7 @@ def TemporaryFile(mode='w+b', buffering=-1, encoding=None,
             fd = None
             def opener(*args):
                 nonlocal fd
-                flags2 = (flags | _os.O_TMPFILE) & ~_os.O_CREAT
+                flags2 = (flags | _os.O_TMPFILE) & ~_os.O_CREAT & ~_os.O_EXCL
                 fd = _os.open(dir, flags2, 0o600)
                 return fd
             try:
diff --git a/Misc/NEWS.d/next/Library/2025-07-04-12-53-02.gh-issue-136156.OYlXoz.rst b/Misc/NEWS.d/next/Library/2025-07-04-12-53-02.gh-issue-136156.OYlXoz.rst
@@ -0,0 +1,3 @@
+:func:`tempfile.TemporaryFile` no longer uses :data:`os.O_EXCL` with
+:data:`os.O_TMPFILE`, so it's possible to use ``linkat()`` on the file
+descriptor. Patch by Victor Stinner.

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,3 @@`
	`1`	+:func:`tempfile.TemporaryFile` no longer uses :data:`os.O_EXCL` with
	`2`	+:data:`os.O_TMPFILE`, so it's possible to use ``linkat()`` on the file
	`3`	`+descriptor. Patch by Victor Stinner.`