mirrors/pulseaudio
1
0
Fork 0
mirror of https://gitlab.freedesktop.org/pulseaudio/pulseaudio.git synced 2025-11-13 13:29:58 -05:00
Code Issues Projects Releases Packages Wiki Activity Actions

pulsecore: Introduce memfd support

Browse source 
Memfd is a simple memory sharing mechanism, added by the systemd/kdbus
developers, to share pages between processes in an anonymous, no global
registry needed, no mount-point required, relatively secure, manner.

This patch introduces the necessary building blocks for using memfd
shared memory transfers in PulseAudio.

Memfd support shall also help us in laying out the necessary (but not
yet sufficient) groundwork for application sandboxing, protecting PA
from its clients, and protecting clients data from each other.

We plan to exclusively use memfds, instead of POSIX SHM, on the way
forward.

Signed-off-by: Ahmed S. Darwish <darwish.07@gmail.com>
This commit is contained in:
Ahmed S. Darwish 2016-03-13 01:04:18 +02:00 • committed by David Henningsson
parent 1c3a2bcaf1
commit 73e86b1cb1
5 changed files with 231 additions and 66 deletions
Download patch file Download diff file Expand all files Collapse all files

68
src/pulsecore/memfd-wrappers.h Normal file
View file

@ -0,0 +1,68 @@
#ifndef foopulsememfdwrappershfoo
#define foopulsememfdwrappershfoo
/***
This file is part of PulseAudio.
Copyright 2016 Ahmed S. Darwish <darwish.07@gmail.com>
PulseAudio 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.
PulseAudio 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 PulseAudio; if not, see <http://www.gnu.org/licenses/>.
***/
#ifdef HAVE_MEMFD
#include <sys/syscall.h>
#include <fcntl.h>
/*
* No glibc wrappers exist for memfd_create(2), so provide our own.
*
* Also define memfd fcntl sealing macros. While they are already
* defined in the kernel header file <linux/fcntl.h>, that file as
* a whole conflicts with the original glibc header <fnctl.h>.
*/
static inline int memfd_create(const char *name, unsigned int flags) {
return syscall(SYS_memfd_create, name, flags);
}
/* memfd_create(2) flags */
#ifndef MFD_CLOEXEC
#define MFD_CLOEXEC 0x0001U
#endif
#ifndef MFD_ALLOW_SEALING
#define MFD_ALLOW_SEALING 0x0002U
#endif
/* fcntl() seals-related flags */
#ifndef F_LINUX_SPECIFIC_BASE
#define F_LINUX_SPECIFIC_BASE 1024
#endif
#ifndef F_ADD_SEALS
#define F_ADD_SEALS (F_LINUX_SPECIFIC_BASE + 9)
#define F_GET_SEALS (F_LINUX_SPECIFIC_BASE + 10)
#define F_SEAL_SEAL 0x0001 /* prevent further seals from being set */
#define F_SEAL_SHRINK 0x0002 /* prevent file from shrinking */
#define F_SEAL_GROW 0x0004 /* prevent file from growing */
#define F_SEAL_WRITE 0x0008 /* prevent writes */
#endif
#endif /* HAVE_MEMFD */
#endif