Add itimer-related syscall tests

regression/apps/itimer/setitimer.c

@@ -0,0 +1,91 @@
+// SPDX-License-Identifier: MPL-2.0
+
+#include <stdio.h>
+#include <sys/time.h>
+#include <signal.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <time.h>
+#include <string.h>
+
+volatile sig_atomic_t counter = 0;
+
+void timer_handler(int signum)
+{
+	counter++;
+}
+
+int main()
+{
+	struct itimerval timer;
+	struct sigaction sa;
+	int target_count = 3;
+	struct timespec start_time, end_time;
+
+	memset(&sa, 0, sizeof(sa));
+	sa.sa_handler = &timer_handler;
+	sa.sa_flags = SA_RESTART;
+	sigaction(SIGALRM, &sa, NULL);
+
+	// Set the interval to 1.
+	timer.it_value.tv_sec = 1;
+	timer.it_value.tv_usec = 0;
+	timer.it_interval.tv_sec = 1;
+	timer.it_interval.tv_usec = 0;
+
+	// Start timer.
+	if (setitimer(ITIMER_REAL, &timer, NULL) == -1) {
+		perror("Error calling setitimer()");
+		return EXIT_FAILURE;
+	}
+
+	if (clock_gettime(CLOCK_REALTIME, &start_time) == -1) {
+		perror("Error calling clock_gettime()");
+		return EXIT_FAILURE;
+	}
+
+	while (counter < target_count) {
+		struct itimerval timer_state;
+		if (getitimer(ITIMER_REAL, &timer_state) == -1) {
+			perror("Error calling getitimer()");
+			return EXIT_FAILURE;
+		}
+
+		if (timer_state.it_interval.tv_sec == 1 &&
+		    timer_state.it_value.tv_sec == 0) {
+			sleep(1);
+		} else {
+			perror("Error record time in the timer");
+			return EXIT_FAILURE;
+		}
+	}
+
+	timer.it_value.tv_sec = 0;
+	timer.it_value.tv_usec = 0;
+	timer.it_interval.tv_sec = 0;
+	timer.it_interval.tv_usec = 0;
+	// Stop timer.
+	if (setitimer(ITIMER_REAL, &timer, NULL) == -1) {
+		perror("Error calling setitimer()");
+		return EXIT_FAILURE;
+	}
+
+	if (clock_gettime(CLOCK_REALTIME, &end_time) == -1) {
+		perror("Error calling clock_gettime()");
+		return EXIT_FAILURE;
+	}
+
+	int elapsed_time = (int)(end_time.tv_sec - start_time.tv_sec);
+
+	printf("Timer was set to go off every second for a total of %d times.\n",
+	       target_count);
+	printf("Elapsed time: %d seconds.\n", elapsed_time);
+
+	if (elapsed_time == target_count) {
+		printf("The actual elapsed time matches the expected time.\n");
+	} else {
+		printf("There is a discrepancy between actual and expected time.\n");
+	}
+
+	return EXIT_SUCCESS;
+}