bpo-26836: Add os.memfd_create() (#13567)

* bpo-26836: Add os.memfd_create()

* Use the glibc wrapper for memfd_create()

Co-Authored-By: Christian Heimes <christian@python.org>

* Fix deletions caused by autoreconf.

* Use MFD_CLOEXEC as the default value for *flags*.

* Add memset_s to configure.ac.

* Revert memset_s changes.

* Apply the requested changes.

* Tweak the docs.

1 files changed, 38 insertions, 0 deletions

diff --git a/Doc/library/os.rst b/Doc/library/os.rst
index 6df2b49..b53fd71 100644
--- a/Doc/library/os.rst
+++ b/Doc/library/os.rst
@@ -2982,6 +2982,44 @@ features:
       Added support for :class:`bytes` paths.
 
 
+.. function:: memfd_create(name[, flags=os.MFD_CLOEXEC])
+
+   Create an anonymous file and return a file descriptor that refers to it.
+   *flags* must be one of the ``os.MFD_*`` constants available on the system
+   (or a bitwise ORed combination of them).  By default, the new file
+   descriptor is :ref:`non-inheritable <fd_inheritance>`.
+
+   .. availability:: Linux 3.17 or newer with glibc 2.27 or newer.
+
+   .. versionadded:: 3.8
+
+
+.. data:: MFD_CLOEXEC
+          MFD_ALLOW_SEALING
+          MFD_HUGETLB
+          MFD_HUGE_SHIFT
+          MFD_HUGE_MASK
+          MFD_HUGE_64KB
+          MFD_HUGE_512KB
+          MFD_HUGE_1MB
+          MFD_HUGE_2MB
+          MFD_HUGE_8MB
+          MFD_HUGE_16MB
+          MFD_HUGE_32MB
+          MFD_HUGE_256MB
+          MFD_HUGE_512MB
+          MFD_HUGE_1GB
+          MFD_HUGE_2GB
+          MFD_HUGE_16GB
+
+   These flags can be passed to :func:`memfd_create`.
+
+   .. availability:: Linux 3.17 or newer with glibc 2.27 or newer.  The
+      ``MFD_HUGE*`` flags are only available since Linux 4.14.
+
+   .. versionadded:: 3.8
+
+
 Linux extended attributes
 ~~~~~~~~~~~~~~~~~~~~~~~~~