[PATCH RFC] Add support for linux memfd_create syscall

[David Herrmann <dh dot herrmann at gmail dot com>]

The memfd_create() syscall was released with linux-3.17. It's a linux-only
syscall and returns a shmem file-descriptor backed by anonymous memory
in a kernel-internal shmem mount.
---
 ChangeLog                             |  7 +++++++
 NEWS                                  |  2 ++
 sysdeps/unix/sysv/linux/Makefile      |  2 +-
 sysdeps/unix/sysv/linux/Versions      |  3 +++
 sysdeps/unix/sysv/linux/sys/memfd.h   | 32 ++++++++++++++++++++++++++++++++
 sysdeps/unix/sysv/linux/syscalls.list |  2 ++
 6 files changed, 47 insertions(+), 1 deletion(-)
 create mode 100644 sysdeps/unix/sysv/linux/sys/memfd.h

diff --git a/ChangeLog b/ChangeLog
index 6c6d9d8..e11c875 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2014-10-17  David Herrmann  <dh.herrmann@gmail.com>
+
+	* sysdeps/unix/sysv/linux/Makefile: add sys/memfd.h
+	* sysdeps/unix/sysv/linux/Versions: export memfd_create
+	* sysdeps/unix/sysv/linux/syscalls.list: add entry for memfd_create
+	* sysdeps/unix/sysv/linux/sys/memfd.h: new file
+
 2014-10-16  Roland McGrath  <roland@hack.frob.com>
 
 	* sysdeps/arm/soft-fp/sfp-machine.h: Filed moved ...
diff --git a/NEWS b/NEWS
index 987f306..b6af068 100644
--- a/NEWS
+++ b/NEWS
@@ -7,6 +7,8 @@ using `glibc' in the "product" field.
 
 Version 2.21
 
+* New Linux interfaces: memfd_create
+
 * The following bugs are resolved with this release:
 
   6652, 12926, 14171, 17266, 17363, 17370, 17371, 17411, 17460.
diff --git a/sysdeps/unix/sysv/linux/Makefile b/sysdeps/unix/sysv/linux/Makefile
index 9ad6d22..850ef9b 100644
--- a/sysdeps/unix/sysv/linux/Makefile
+++ b/sysdeps/unix/sysv/linux/Makefile
@@ -43,7 +43,7 @@ sysdep_headers += sys/mount.h sys/acct.h sys/sysctl.h \
 		  sys/timerfd.h sys/fanotify.h bits/eventfd.h bits/inotify.h \
 		  bits/signalfd.h bits/timerfd.h bits/epoll.h \
 		  bits/socket_type.h bits/syscall.h bits/sysctl.h \
-		  bits/mman-linux.h
+		  bits/mman-linux.h sys/memfd.h
 
 tests += tst-clone tst-fanotify
 
diff --git a/sysdeps/unix/sysv/linux/Versions b/sysdeps/unix/sysv/linux/Versions
index 16bb281..15c04b5 100644
--- a/sysdeps/unix/sysv/linux/Versions
+++ b/sysdeps/unix/sysv/linux/Versions
@@ -166,6 +166,9 @@ libc {
   GLIBC_2.15 {
     process_vm_readv; process_vm_writev;
   }
+  GLIBC_2.21 {
+    memfd_create;
+  }
   GLIBC_PRIVATE {
     # functions used in other libraries
     __syscall_rt_sigqueueinfo;
diff --git a/sysdeps/unix/sysv/linux/sys/memfd.h b/sysdeps/unix/sysv/linux/sys/memfd.h
new file mode 100644
index 0000000..3f10df4
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/sys/memfd.h
@@ -0,0 +1,32 @@
+/* Copyright (C) 2010-2014 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#ifndef	_SYS_MEMFD_H
+#define	_SYS_MEMFD_H	1
+
+#include <stdint.h>
+#include <linux/memfd.h>
+
+__BEGIN_DECLS
+
+/* Create and initialize an anonymous memory object.  */
+extern int memfd_create (const char *__name, unsigned int __flags)
+  __THROW;
+
+__END_DECLS
+
+#endif /* sys/memfd.h */
diff --git a/sysdeps/unix/sysv/linux/syscalls.list b/sysdeps/unix/sysv/linux/syscalls.list
index a0b8de8..f881f37 100644
--- a/sysdeps/unix/sysv/linux/syscalls.list
+++ b/sysdeps/unix/sysv/linux/syscalls.list
@@ -123,3 +123,5 @@ setns		EXTRA	setns		i:ii	setns
 
 process_vm_readv EXTRA	process_vm_readv i:ipipii process_vm_readv
 process_vm_writev EXTRA	process_vm_writev i:ipipii process_vm_writev
+
+memfd_create	EXTRA	memfd_create	i:si	memfd_create
-- 
2.1.2