Implement memfd_create() fallback if not available in system libc.
memfd_create() is still not included in glibc today, atlhough it's been
available since Linux 3.17 in Oct 2014.
memfd has numerous advantages over traditional shm/mmap for ipc memory
sharing with fd handler, which we are going to make use of for
vhost-user logging memory in following patches.
Signed-off-by: Marc-André Lureau <marcandre.lur...@redhat.com>
---
include/qemu/osdep.h | 59 ++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 59 insertions(+)
diff --git a/include/qemu/osdep.h b/include/qemu/osdep.h
index 3247364..adc138b 100644
--- a/include/qemu/osdep.h
+++ b/include/qemu/osdep.h
@@ -6,6 +6,7 @@
#include <stddef.h>
#include <stdbool.h>
#include <stdint.h>
+#include <unistd.h>
#include <sys/types.h>
#ifdef __OpenBSD__
#include <sys/signal.h>
@@ -20,6 +21,64 @@
#include <sys/time.h>
+#ifdef CONFIG_LINUX
+
+#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
+
+#ifndef MFD_ALLOW_SEALING
+#define MFD_ALLOW_SEALING 0x0002U
+#endif
+
+#ifndef MFD_CLOEXEC
+#define MFD_CLOEXEC 0x0001U
+#endif
+
+#ifndef __NR_memfd_create
+# if defined __x86_64__
+# define __NR_memfd_create 319
+# elif defined __arm__
+# define __NR_memfd_create 385
+# elif defined __aarch64__
+# define __NR_memfd_create 279
+# elif defined _MIPS_SIM
+# if _MIPS_SIM == _MIPS_SIM_ABI32
+# define __NR_memfd_create 4354
+# endif
+# if _MIPS_SIM == _MIPS_SIM_NABI32
+# define __NR_memfd_create 6318
+# endif
+# if _MIPS_SIM == _MIPS_SIM_ABI64
+# define __NR_memfd_create 5314
+# endif
+# elif defined __i386__
+# define __NR_memfd_create 356
+# else
+# warning "__NR_memfd_create unknown for your architecture"
+# define __NR_memfd_create 0xffffffff
+# endif
+#endif
+
+#ifndef CONFIG_MEMFD
+static inline int memfd_create(const char *name, unsigned int flags)
+{
+ return syscall(__NR_memfd_create, name, flags);
+}
+#endif
+
+#endif /* LINUX */
+
#if defined(CONFIG_SOLARIS) && CONFIG_SOLARIS_VERSION < 10
/* [u]int_fast*_t not in <sys/int_types.h> */
typedef unsigned char uint_fast8_t;
--
2.4.3
