backend: use fcntl(F_DUPFD_CLOEXEC) instead of dup

This makes sure the CLOEXEC flag is set on the dup'ed FD.

1 files changed, 5 insertions, 5 deletions

diff --git a/backend/x11/backend.c b/backend/x11/backend.c
index 9482f86d..48f1aaee 100644
--- a/backend/x11/backend.c
+++ b/backend/x11/backend.c
@@ -1,6 +1,6 @@
-#define _POSIX_C_SOURCE 200112L
-
+#define _POSIX_C_SOURCE 200809L
 #include <assert.h>
+#include <fcntl.h>
 #include <limits.h>
 #include <stdbool.h>
 #include <stdio.h>
@@ -490,9 +490,9 @@ struct wlr_backend *wlr_x11_backend_create(struct wl_display *display,
 		return false;
 	}
 
-	drm_fd = dup(drm_fd);
-	if (fd < 0) {
-		wlr_log_errno(WLR_ERROR, "dup failed");
+	drm_fd = fcntl(drm_fd, F_DUPFD_CLOEXEC, 0);
+	if (drm_fd < 0) {
+		wlr_log_errno(WLR_ERROR, "fcntl(F_DUPFD_CLOEXEC) failed");
 		return false;
 	}