[PATCH v2 2/2] selftests: liveupdate: Add tests for LIVEUPDATE_SESSION_FREEZE

[Pasha Tatashin]

Provide luo_session_freeze() in the liveupdate test library and add unit
tests in liveupdate.c covering the LIVEUPDATE_SESSION_FREEZE ioctl. The
tests verify that non-zero reserved bits are rejected with -EINVAL, an
outgoing session with preserved files can be frozen early, freezing an
already frozen session returns -EBUSY, and attempting to preserve an
additional file descriptor into a frozen session fails with -EBUSY.

Also freeze the test session early in luo_kexec_simple.c to exercise
LIVEUPDATE_SESSION_FREEZE across a kexec reboot, and verify that
attempting to freeze a retrieved incoming session returns -EINVAL.

Signed-off-by: Pasha Tatashin <pasha.tatashin@xxxxxxxxxx>
---
 .../liveupdate/lib/include/libliveupdate.h    |  1 +
 .../selftests/liveupdate/lib/lu_utils.c       | 10 ++++
 .../testing/selftests/liveupdate/liveupdate.c | 49 +++++++++++++++++++
 .../selftests/liveupdate/luo_kexec_simple.c   |  8 +++
 4 files changed, 68 insertions(+)

diff --git a/tools/testing/selftests/liveupdate/lib/include/libliveupdate.h b/tools/testing/selftests/liveupdate/lib/include/libliveupdate.h
index fa07fed08364..15a7db3a6b3e 100644
--- a/tools/testing/selftests/liveupdate/lib/include/libliveupdate.h
+++ b/tools/testing/selftests/liveupdate/lib/include/libliveupdate.h
@@ -26,6 +26,7 @@ int luo_create_session(int luo_fd, const char *name);
 int luo_retrieve_session(int luo_fd, const char *name);
 int luo_session_finish(int session_fd);
 int luo_get_session_name(int session_fd, char *name, size_t name_len);
+int luo_session_freeze(int session_fd);
 
 int luo_ensure_nofile_limit(long min_limit);
 int luo_session_preserve_fd(int session_fd, int fd, __u64 token);
diff --git a/tools/testing/selftests/liveupdate/lib/lu_utils.c b/tools/testing/selftests/liveupdate/lib/lu_utils.c
index 74d41115c281..6315746ff08f 100644
--- a/tools/testing/selftests/liveupdate/lib/lu_utils.c
+++ b/tools/testing/selftests/liveupdate/lib/lu_utils.c
@@ -198,6 +198,16 @@ int luo_session_finish(int session_fd)
 	return 0;
 }
 
+int luo_session_freeze(int session_fd)
+{
+	struct liveupdate_session_freeze arg = { .size = sizeof(arg) };
+
+	if (ioctl(session_fd, LIVEUPDATE_SESSION_FREEZE, &arg) < 0)
+		return -errno;
+
+	return 0;
+}
+
 void create_state_file(int luo_fd, const char *session_name, int token,
 		       int next_stage)
 {
diff --git a/tools/testing/selftests/liveupdate/liveupdate.c b/tools/testing/selftests/liveupdate/liveupdate.c
index 2dedd5fc2534..74004e4276f5 100644
--- a/tools/testing/selftests/liveupdate/liveupdate.c
+++ b/tools/testing/selftests/liveupdate/liveupdate.c
@@ -530,4 +530,53 @@ TEST_F(liveupdate_device, preserve_many_files)
 	ASSERT_EQ(close(session_fd), 0);
 }
 
+/*
+ * Test Case: Session Freeze
+ *
+ * Verifies that an outgoing session can be frozen early via
+ * LIVEUPDATE_SESSION_FREEZE, rejects non-zero reserved bits with -EINVAL,
+ * that subsequent freeze attempts return -EBUSY, and that attempting to
+ * preserve an additional file descriptor into a frozen session fails with
+ * -EBUSY.
+ */
+TEST_F(liveupdate_device, session_freeze)
+{
+	struct liveupdate_session_freeze bad_arg = {
+		.size = sizeof(bad_arg),
+		.reserved = 1,
+	};
+	int session_fd, mem_fd1, mem_fd2;
+
+	self->fd1 = open(LIVEUPDATE_DEV, O_RDWR);
+	if (self->fd1 < 0 && errno == ENOENT)
+		SKIP(return, "%s does not exist", LIVEUPDATE_DEV);
+	ASSERT_GE(self->fd1, 0);
+
+	session_fd = luo_create_session(self->fd1, "session-freeze-test");
+	ASSERT_GE(session_fd, 0);
+
+	mem_fd1 = memfd_create("freeze-memfd-1", 0);
+	ASSERT_GE(mem_fd1, 0);
+	ASSERT_EQ(luo_session_preserve_fd(session_fd, mem_fd1, 0x1111), 0);
+
+	/* Non-zero reserved field must fail with -EINVAL */
+	EXPECT_EQ(ioctl(session_fd, LIVEUPDATE_SESSION_FREEZE, &bad_arg), -1);
+	EXPECT_EQ(errno, EINVAL);
+
+	/* Freeze the session early */
+	ASSERT_EQ(luo_session_freeze(session_fd), 0);
+
+	/* Subsequent freeze attempt on an already frozen session must fail with -EBUSY */
+	EXPECT_EQ(luo_session_freeze(session_fd), -EBUSY);
+
+	/* Preserving a file after freeze must fail with -EBUSY */
+	mem_fd2 = memfd_create("freeze-memfd-2", 0);
+	ASSERT_GE(mem_fd2, 0);
+	EXPECT_EQ(luo_session_preserve_fd(session_fd, mem_fd2, 0x2222), -EBUSY);
+
+	ASSERT_EQ(close(session_fd), 0);
+	ASSERT_EQ(close(mem_fd1), 0);
+	ASSERT_EQ(close(mem_fd2), 0);
+}
+
 TEST_HARNESS_MAIN
diff --git a/tools/testing/selftests/liveupdate/luo_kexec_simple.c b/tools/testing/selftests/liveupdate/luo_kexec_simple.c
index 786ac93b9ae3..9bc8dab2e074 100644
--- a/tools/testing/selftests/liveupdate/luo_kexec_simple.c
+++ b/tools/testing/selftests/liveupdate/luo_kexec_simple.c
@@ -40,6 +40,11 @@ static void run_stage_1(int luo_fd)
 			  TEST_MEMFD_TOKEN);
 	}
 
+	ksft_print_msg("[STAGE 1] Freezing session '%s' early...\n",
+		       TEST_SESSION_NAME);
+	if (luo_session_freeze(session_fd) < 0)
+		fail_exit("luo_session_freeze for '%s'", TEST_SESSION_NAME);
+
 	close(luo_fd);
 	daemonize_and_wait();
 }
@@ -60,6 +65,9 @@ static void run_stage_2(int luo_fd, int state_session_fd)
 	if (session_fd < 0)
 		fail_exit("luo_retrieve_session for '%s'", TEST_SESSION_NAME);
 
+	if (luo_session_freeze(session_fd) != -EINVAL)
+		fail_exit("luo_session_freeze on incoming session did not return -EINVAL");
+
 	ksft_print_msg("[STAGE 2] Restoring and verifying memfd (token %#x)...\n",
 		       TEST_MEMFD_TOKEN);
 	mfd = restore_and_verify_memfd(session_fd, TEST_MEMFD_TOKEN,
-- 
2.56.0.212.g129ede20d9-goog