[PATCH 3/7] Use O_TMPFILE if available

[Keith Packard]

Signed-off-by: Keith Packard <keithp at keithp.com>
---
 src/xshmfence.c    | 14 ++++++++++----
 src/xshmfenceint.h |  2 ++
 2 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/src/xshmfence.c b/src/xshmfence.c
index ecf2f4a..ed2b4c4 100644
--- a/src/xshmfence.c
+++ b/src/xshmfence.c
@@ -97,7 +97,6 @@ xshmfence_reset(struct xshmfence *f)
 	__sync_bool_compare_and_swap(&f->v, 1, 0);
 }
 
-
 /**
  * xshmfence_alloc_shm:
  *
@@ -111,12 +110,19 @@ int
 xshmfence_alloc_shm(void)
 {
 	char	template[] = SHMDIR "/shmfd-XXXXXX";
-	int	fd = mkstemp(template);
+	int	fd;
 
+#ifdef O_TMPFILE
+	fd = open(SHMDIR, O_TMPFILE|O_RDWR|O_CLOEXEC|O_EXCL, 0666);
 	if (fd < 0)
+#endif
+        {
+            fd = mkstemp(template);
+            if (fd < 0)
 		return fd;
-	unlink(template);
-	ftruncate(fd, sizeof (int32_t));
+            unlink(template);
+        }
+	ftruncate(fd, sizeof (struct xshmfence));
 	return fd;
 }
 
diff --git a/src/xshmfenceint.h b/src/xshmfenceint.h
index e7b8b2a..66862d0 100644
--- a/src/xshmfenceint.h
+++ b/src/xshmfenceint.h
@@ -32,6 +32,8 @@
 #include <unistd.h>
 #include <sys/syscall.h>
 #include <sys/mman.h>
+#include <sys/stat.h>
+#include <fcntl.h>
 #include <errno.h>
 #include <values.h>
 #include "xshmfence.h"
-- 
1.8.4.2