add configure check and shim for landlock

First move towards landlock support (#3).  The shim is needed until
libc provides the proper wrappers for the landlock APIs; I hope it
doesn't take too long, but landlock was merged back in May and are
still missing.

1 files changed, 30 insertions, 0 deletions

diff --git a/have/landlock.c b/have/landlock.c
new file mode 100644
index 0000000..8be29bd
--- /dev/null
+++ b/have/landlock.c
@@ -0,0 +1,30 @@
+/*
+ * Copyright (c) 2021 Omar Polo <op@omarpolo.com>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include "../landlock_shim.h"
+
+int
+main(void)
+{
+	int rfd;
+	struct landlock_ruleset_attr rsattr = {
+		.handled_access_fs =	LANDLOCK_ACCESS_FS_READ_FILE |
+					LANDLOCK_ACCESS_FS_READ_DIR
+	};
+
+	rfd = landlock_create_ruleset(&rsattr, sizeof(rsattr), 0);
+	return rfd == -1;
+}