bpf: Exercise syscall operations for inode and sk storage

Use the check_syscall_operations added for task_local_storage to
exercise syscall operations for other local storage maps:

* Check the absence of an element for the given fd.
* Create a new element, retrieve and compare its value.
* Delete the element and check again for absence.
Signed-off-by: KP Singh <kpsingh@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20201106103747.2780972-10-kpsingh@chromium.org

tools/testing/selftests/bpf/prog_tests/test_local_storage.c

@@ -157,7 +157,7 @@ static bool check_syscall_operations(int map_fd, int obj_fd)
 void test_test_local_storage(void)
 {
 	char tmp_exec_path[PATH_MAX] = "/tmp/copy_of_rmXXXXXX";
-	int err, serv_sk = -1, task_fd = -1;
+	int err, serv_sk = -1, task_fd = -1, rm_fd = -1;
 	struct local_storage *skel = NULL;
 
 	skel = local_storage__open_and_load();
@@ -181,6 +181,15 @@ void test_test_local_storage(void)
 	if (CHECK(err < 0, "copy_rm", "err %d errno %d\n", err, errno))
 		goto close_prog;
 
+	rm_fd = open(tmp_exec_path, O_RDONLY);
+	if (CHECK(rm_fd < 0, "open", "failed to open %s err:%d, errno:%d",
+		  tmp_exec_path, rm_fd, errno))
+		goto close_prog;
+
+	if (!check_syscall_operations(bpf_map__fd(skel->maps.inode_storage_map),
+				      rm_fd))
+		goto close_prog;
+
 	/* Sets skel->bss->monitored_pid to the pid of the forked child
 	 * forks a child process that executes tmp_exec_path and tries to
 	 * unlink its executable. This operation should be denied by the loaded
@@ -209,11 +218,15 @@ void test_test_local_storage(void)
 	CHECK(skel->data->sk_storage_result != 0, "sk_storage_result",
 	      "sk_local_storage not set\n");
 
-	close(serv_sk);
+	if (!check_syscall_operations(bpf_map__fd(skel->maps.sk_storage_map),
+				      serv_sk))
+		goto close_prog;
 
 close_prog_unlink:
 	unlink(tmp_exec_path);
 close_prog:
+	close(serv_sk);
+	close(rm_fd);
 	close(task_fd);
 	local_storage__destroy(skel);
 }