Update MentOs code to the latest development version.

programs/tests/t_itimer.c

@@ -0,0 +1,62 @@
+///                MentOS, The Mentoring Operating system project
+/// @file t_itimer.c
+/// @brief
+/// @copyright (c) 2014-2021 This file is distributed under the MIT License.
+/// See LICENSE.md for details.
+
+#include <sys/unistd.h>
+#include <signal.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <strerror.h>
+#include <sys/wait.h>
+#include <time.h>
+
+void alarm_handler(int sig)
+{
+    printf("handler(%d) : Starting handler.\n", sig);
+    if (sig == SIGALRM) {
+
+        itimerval val = { 0 };
+        getitimer(ITIMER_REAL, &val);
+        printf("(sec: %d, usec: %d)\n", val.it_interval.tv_sec, val.it_interval.tv_usec);
+
+        static int counter = 0;
+        counter += 1;
+
+        printf("handler(%d) : Correct signal x%d\n", sig, counter);
+        if (counter == 4)
+        {
+            itimerval interval = { 0 }, prev = { 0 };
+            interval.it_interval.tv_sec = 0;
+
+            setitimer(ITIMER_REAL, &interval, &prev);
+            printf("prev: (sec: %d, usec: %d)", prev.it_interval.tv_sec, prev.it_interval.tv_usec);
+
+            exit(0);
+        }
+
+    } else {
+        printf("handler(%d) : Wrong signal.\n", sig);
+    }
+    printf("handler(%d) : Ending handler.\n", sig);
+}
+
+int main(int argc, char *argv[])
+{
+    sigaction_t action;
+    memset(&action, 0, sizeof(action));
+    action.sa_handler = alarm_handler;
+    if (sigaction(SIGALRM, &action, NULL) == -1) {
+        printf("Failed to set signal handler (%s).\n", SIGALRM, strerror(errno));
+        return 1;
+    }
+
+    itimerval interval = { 0 };
+    interval.it_interval.tv_sec = 4;
+    setitimer(ITIMER_REAL, &interval, NULL);
+
+    while(1) { }
+    return 0;
+}