[PATCH v3 4/5] selftests/resctrl: Cleanup properly when an error occurs in CAT test

[Shaopeng Tan <tan.shaopeng@xxxxxxxxxxxxxx>]

After creating a child process with fork() in CAT test, if there is
an error occurs or such as a SIGINT signal is received, the parent
process will be terminated immediately, but the child process will not
be killed and also umount_resctrlfs() will not be called.

Add a signal handler like other tests to kill child process, umount
resctrlfs, cleanup result files, etc. when an error occurs.

Signed-off-by: Shaopeng Tan <tan.shaopeng@xxxxxxxxxxxxxx>
---
 tools/testing/selftests/resctrl/cat_test.c | 28 +++++++++++++++-------
 1 file changed, 19 insertions(+), 9 deletions(-)

diff --git a/tools/testing/selftests/resctrl/cat_test.c b/tools/testing/selftests/resctrl/cat_test.c
index 6a8306b0a109..5f81817f4366 100644
--- a/tools/testing/selftests/resctrl/cat_test.c
+++ b/tools/testing/selftests/resctrl/cat_test.c
@@ -98,12 +98,21 @@ void cat_test_cleanup(void)
 	remove(RESULT_FILE_NAME2);
 }
 
+static void ctrl_handler(int signo)
+{
+	kill(bm_pid, SIGKILL);
+	umount_resctrlfs();
+	tests_cleanup();
+	ksft_print_msg("Ending\n\n");
+
+	exit(EXIT_SUCCESS);
+}
+
 int cat_perf_miss_val(int cpu_no, int n, char *cache_type)
 {
 	unsigned long l_mask, l_mask_1;
 	int ret, pipefd[2], sibling_cpu_no;
 	char pipe_message;
-	pid_t bm_pid;
 
 	cache_size = 0;
 
@@ -181,17 +190,19 @@ int cat_perf_miss_val(int cpu_no, int n, char *cache_type)
 		strcpy(param.filename, RESULT_FILE_NAME1);
 		param.num_of_runs = 0;
 		param.cpu_no = sibling_cpu_no;
+	} else {
+		/* set up ctrl-c handler */
+		if (signal(SIGINT, ctrl_handler) == SIG_ERR ||
+		    signal(SIGHUP, ctrl_handler) == SIG_ERR ||
+		    signal(SIGTERM, ctrl_handler) == SIG_ERR)
+			printf("Failed to catch SIGNAL!\n");
 	}
 
 	remove(param.filename);
 
 	ret = cat_val(&param);
-	if (ret)
-		return ret;
-
-	ret = check_results(&param);
-	if (ret)
-		return ret;
+	if (ret == 0)
+		ret = check_results(&param);
 
 	if (bm_pid == 0) {
 		/* Tell parent that child is ready */
@@ -201,7 +212,6 @@ int cat_perf_miss_val(int cpu_no, int n, char *cache_type)
 		    sizeof(pipe_message)) {
 			close(pipefd[1]);
 			perror("# failed signaling parent process");
-			return errno;
 		}
 
 		close(pipefd[1]);
@@ -226,5 +236,5 @@ int cat_perf_miss_val(int cpu_no, int n, char *cache_type)
 	if (bm_pid)
 		umount_resctrlfs();
 
-	return 0;
+	return ret;
 }
-- 
2.27.0