freeze: add freeze_thaw test

Change-Id: I31db80b89adca9ac354a96ad21073b269d8a0e24

test/freeze_thaw/cmd/fork.c

@@ -0,0 +1,54 @@
+/* fork.c COPYRIGHT FUJITSU LIMITED 2019 */
+#include <stdio.h>
+#include <unistd.h>
+#include <errno.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <stdlib.h>
+
+static void waitChildren(void)
+{
+	for (;;) {
+		int status = 0;
+		pid_t pid = wait(&status);
+
+		if (pid == -1) {
+			const char msg[] = "wait fail\n";
+
+			if (errno == ECHILD) {
+				return;
+			} else if (errno == EINTR) {
+				continue;
+			}
+			write(STDERR_FILENO, msg, sizeof(msg));
+			_exit(-1);
+		}
+	}
+}
+
+int main(int argc, char **argv)
+{
+	int ret = 0;
+	int nr_fork;
+	int i;
+
+	if (argc < 2) {
+		printf("usage: %s <nr_fork>\n", argv[0]);
+		return 1;
+	}
+	nr_fork = atoi(argv[1]);
+
+	for (i = 0; i < nr_fork; i++) {
+		pid_t pid = fork();
+
+		if (pid < 0) {
+			perror("fork");
+			ret = -1;
+			break;
+		} else if (pid == 0) {
+			exit(0);
+		}
+	}
+	waitChildren();
+	return ret;
+}