pulseaudio/src/pulsecore/memfd-wrappers.h

#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/>.
***/

#if defined(HAVE_MEMFD) && !defined(HAVE_MEMFD_CREATE)

#include <sys/syscall.h>
#include <fcntl.h>

/*
 * Before glibc version 2.27 there was no wrapper for memfd_create(2),
 * so we have to 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 && !HAVE_MEMFD_CREATE */

#endif