1 files changed, 30 insertions, 0 deletions
diff --git a/libsandbox/pre_check_openat.c b/libsandbox/pre_check_openat.c
new file mode 100644
index 0000000..99c03eb
--- /dev/null
+++ b/libsandbox/pre_check_openat.c
@@ -0,0 +1,30 @@
+/*
+ * open*() pre-check.
+ *
+ * Copyright 1999-2012 Gentoo Foundation
+ * Licensed under the GPL-2
+ */
+
+#include "headers.h"
+#include "sbutil.h"
+#include "libsandbox.h"
+#include "wrappers.h"
+
+bool sb_openat_pre_check(const char *func, const char *pathname, int dirfd, int flags)
+{
+	/* If we're not trying to create, fail normally if file does not stat */
+	if (flags & O_CREAT)
+		return true;
+
+	save_errno();
+
+	/* Doesn't exist -> skip permission checks */
+	if (sb_exists(dirfd, pathname, (flags & O_NOFOLLOW) ? AT_SYMLINK_NOFOLLOW : 0) == -1) {
+		sb_debug_dyn("EARLY FAIL: %s(%s): %s\n", func, pathname, strerror(errno));
+		return false;
+	}
+
+	restore_errno();
+
+	return true;
+}