shmfd example: use O_TMPFILE. Create multiple segments

Signed-off-by: Keith Packard <keithp@keithp.com>

1 files changed, 55 insertions, 5 deletions

diff --git a/shmfd.c b/shmfd.c
index 45b9067..2094efa 100644
--- a/shmfd.c
+++ b/shmfd.c
@@ -27,17 +27,43 @@
 #include <xcb/shm.h>
 #include <xcb/xcb_aux.h>
 #include <unistd.h>
+#include <fcntl.h>
+
+#define __O_TMPFILE    020000000
+#define O_TMPFILE (__O_TMPFILE | O_DIRECTORY)
 
 int
-make_shm(int size, void **addrp)
+shm_tmpfile(void)
 {
-	void	*addr;
+	int	fd;
+	int	flags;
 	char	template[] = "/run/shm/shmfd-XXXXXX";
-	int	fd = mkstemp(template);
-
-	if (fd < 0)
+#ifdef O_TMPFILE
+	fd = open("/run/shm", O_TMPFILE|O_RDWR|O_CLOEXEC|O_EXCL, 0666);
+	if (fd >= 0) {
+		printf ("Using O_TMPFILE\n");
 		return fd;
+	}
+	printf ("Not using O_TMPFILE\n");
+	perror("O_TMPFILE");
+#endif
+	fd = mkstemp(template);
+	if (fd < 0)
+		return -1;
 	unlink(template);
+	if (fcntl(fd, F_GETFD, &flags) >= 0) {
+		flags |= FD_CLOEXEC;
+		(void) fcntl(fd, F_SETFD, &flags);
+	}
+	return fd;
+}
+
+int
+make_shm(int size, void **addrp)
+{
+	void	*addr;
+	int	fd = shm_tmpfile();
+
 	ftruncate(fd, size);
 	addr = mmap (NULL, size, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
 	if (addr == MAP_FAILED) {
@@ -78,16 +104,21 @@ main (int argc, char **argv)
 	xcb_screen_t		*screen;
 	int			fd;
 	int			segment_fd;
+	int			segment_fd_2;
 	void			*addr;
 	void			*server_addr;
+	void			*server_addr_2;
 	xcb_shm_seg_t		shm_seg;
 	xcb_shm_seg_t		shm_server_seg;
+	xcb_shm_seg_t		shm_server_seg_2;
 	xcb_gc_t		gc;
 	xcb_window_t		window;
 	xcb_generic_event_t	*event;
 	xcb_generic_error_t	*error;
 	xcb_shm_create_segment_cookie_t	shm_create_segment_cookie;
+	xcb_shm_create_segment_cookie_t	shm_create_segment_cookie_2;
 	xcb_shm_create_segment_reply_t	*shm_create_segment_reply;
+	xcb_shm_create_segment_reply_t	*shm_create_segment_reply_2;
 	xcb_generic_error_t		*shm_create_segment_error;
 	int			*shm_create_segment_fds;
 	uint32_t		window_mask;
@@ -113,6 +144,13 @@ main (int argc, char **argv)
 							   (shm_server_seg = xcb_generate_id(c)),
 							   size,
 							   1);
+	shm_create_segment_cookie_2 = xcb_shm_create_segment(c,
+							   (shm_server_seg_2 = xcb_generate_id(c)),
+							   size,
+							   1);
+	shm_create_segment_reply_2 = xcb_shm_create_segment_reply (c,
+								 shm_create_segment_cookie_2,
+								 &shm_create_segment_error);
 	shm_create_segment_reply = xcb_shm_create_segment_reply (c,
 								 shm_create_segment_cookie,
 								 &shm_create_segment_error);
@@ -128,6 +166,18 @@ main (int argc, char **argv)
 	else
 		server_addr = NULL;
 
+	if (shm_create_segment_reply_2) {
+		shm_create_segment_fds = xcb_shm_create_segment_reply_fds(c,
+									  shm_create_segment_reply_2);
+		segment_fd_2 = shm_create_segment_fds[0];
+
+		server_addr_2 = mmap(NULL, size, PROT_READ|PROT_WRITE, MAP_SHARED, segment_fd_2, 0);
+		free(shm_create_segment_reply_2);
+//		paint(server_addr_2, WIDTH, HEIGHT, 1);
+	}
+	else
+		server_addr_2 = NULL;
+
 	window_mask = XCB_CW_BACK_PIXEL|XCB_CW_EVENT_MASK;
 	window_values[0] = 0xffffff;
 	window_values[1] = XCB_EVENT_MASK_EXPOSURE|XCB_EVENT_MASK_KEY_PRESS;