[PATCH 2/2] selftests: landlock: skip all tests without landlock syscall

[Andre Przywara <andre.przywara@arm.com>]

"landlock" is a relatively new syscall, and most defconfigs do not enable
it (yet). On systems without this syscall available, the selftests fail
at the moment, instead of being skipped.

Check the availability of the landlock system call before executing each
test, and skip the rest of the tests if we get an ENOSYS back.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
---
 tools/testing/selftests/landlock/base_test.c | 27 ++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/tools/testing/selftests/landlock/base_test.c b/tools/testing/selftests/landlock/base_test.c
index 1e3b6de57e80e..c539cec775fba 100644
--- a/tools/testing/selftests/landlock/base_test.c
+++ b/tools/testing/selftests/landlock/base_test.c
@@ -21,12 +21,20 @@
 #define O_PATH 010000000
 #endif
 
+static bool has_syscall(void)
+{
+	return landlock_create_ruleset(NULL, 0, 0) == -1 && errno != ENOSYS;
+}
+
 TEST(inconsistent_attr)
 {
 	const long page_size = sysconf(_SC_PAGESIZE);
 	char *const buf = malloc(page_size + 1);
 	struct landlock_ruleset_attr *const ruleset_attr = (void *)buf;
 
+	if (!has_syscall())
+		SKIP(return, "landlock syscall not available");
+
 	ASSERT_NE(NULL, buf);
 
 	/* Checks copy_from_user(). */
@@ -75,6 +83,10 @@ TEST(abi_version)
 	const struct landlock_ruleset_attr ruleset_attr = {
 		.handled_access_fs = LANDLOCK_ACCESS_FS_READ_FILE,
 	};
+
+	if (!has_syscall())
+		SKIP(return, "landlock syscall not available");
+
 	ASSERT_NE(0, landlock_create_ruleset(NULL, 0,
 					     LANDLOCK_CREATE_RULESET_VERSION));
 
@@ -107,6 +119,9 @@ TEST(create_ruleset_checks_ordering)
 		.handled_access_fs = LANDLOCK_ACCESS_FS_READ_FILE,
 	};
 
+	if (!has_syscall())
+		SKIP(return, "landlock syscall not available");
+
 	/* Checks priority for invalid flags. */
 	ASSERT_EQ(-1, landlock_create_ruleset(NULL, 0, invalid_flag));
 	ASSERT_EQ(EINVAL, errno);
@@ -153,6 +168,9 @@ TEST(add_rule_checks_ordering)
 	const int ruleset_fd =
 		landlock_create_ruleset(&ruleset_attr, sizeof(ruleset_attr), 0);
 
+	if (!has_syscall())
+		SKIP(return, "landlock syscall not available");
+
 	ASSERT_LE(0, ruleset_fd);
 
 	/* Checks invalid flags. */
@@ -200,6 +218,9 @@ TEST(restrict_self_checks_ordering)
 	const int ruleset_fd =
 		landlock_create_ruleset(&ruleset_attr, sizeof(ruleset_attr), 0);
 
+	if (!has_syscall())
+		SKIP(return, "landlock syscall not available");
+
 	ASSERT_LE(0, ruleset_fd);
 	path_beneath_attr.parent_fd =
 		open("/tmp", O_PATH | O_NOFOLLOW | O_DIRECTORY | O_CLOEXEC);
@@ -240,6 +261,9 @@ TEST(ruleset_fd_io)
 	int ruleset_fd;
 	char buf;
 
+	if (!has_syscall())
+		SKIP(return, "landlock syscall not available");
+
 	drop_caps(_metadata);
 	ruleset_fd =
 		landlock_create_ruleset(&ruleset_attr, sizeof(ruleset_attr), 0);
@@ -267,6 +291,9 @@ TEST(ruleset_fd_transfer)
 	pid_t child;
 	int status;
 
+	if (!has_syscall())
+		SKIP(return, "landlock syscall not available");
+
 	drop_caps(_metadata);
 
 	/* Creates a test ruleset with a simple rule. */
-- 
2.25.1