Question 2.2

server_4.c

+#include <iostream>
+#include <csignal>
+#include <cstdlib>
+#include <unistd.h>
+#include <cstring>
+#include <sys/wait.h>
+
+volatile bool running = true;
+int pipefd[2]; // File descriptors for pipe
+
+void print_in_exit() {
+    std::cout << "Message during exit" << std::endl;
+}
+
+void handle_signal(int signal_number) {
+    std::cout << "Received signal: " << signal_number << std::endl;
+    std::cout << "Stopping the program" << std::endl;
+    running = false;
+}
+
+void print_process_info(const char* process_type) {
+    std::cout << process_type << " | id: " << getpid() << std::endl;
+    std::cout << process_type << " | father id: " << getppid() << std::endl;
+    std::cout << process_type << " | groupd id: " << getpgrp() << std::endl;
+}
+
+int main(){
+    std::cout << "started" << std::endl;
+
+    if (atexit(print_in_exit) != 0) {
+        perror("Fail in exit");
+        exit(EXIT_FAILURE);
+    }
+
+    struct sigaction sa;
+    sa.sa_handler = handle_signal;
+    sa.sa_flags = 0;
+    sigemptyset(&sa.sa_mask);
+
+    if (sigaction(SIGINT, &sa, nullptr) == -1) {
+        perror("Fail in exit");
+        exit(EXIT_FAILURE);
+    }
+
+    if (sigaction(SIGTERM, &sa, nullptr) == -1) {
+        perror("Fail in exit");
+        exit(EXIT_FAILURE);
+    }
+
+    // Create the pipe
+    if (pipe(pipefd) == -1) {
+        perror("Pipe failed");
+        exit(EXIT_FAILURE);
+    }
+
+    pid_t pid = fork();
+    if (pid == 0) {
+        close(pipefd[1]);
+
+        int number;
+        while (running) {
+
+            ssize_t bytes_read = read(pipefd[0], &number, sizeof(number));
+            if (bytes_read > 0) {
+                std::cout << "Child received: " << number << std::endl;
+            }
+            sleep(1);
+        }
+
+        close(pipefd[0]);
+    } else {
+        close(pipefd[0]);
+
+        int number = 0;
+        while (running) {
+            print_process_info("Parent");
+
+            write(pipefd[1], &number, sizeof(number));
+            number++;
+
+            sleep(1);
+            int status;
+            pid_t result = waitpid(pid, &status, WNOHANG);
+            if (result == pid) {
+                std::cout << "Child stopped, father stopping" << std::endl;
+                running = false;
+            }
+        }
+
+        close(pipefd[1]);
+    }
+
+    std::cout << "finished" << std::endl;
+
+    return EXIT_SUCCESS;
+}
+/*
+with ctr+c
+Child received: 45
+Parent | id: 2934
+Parent | father id: 2610
+Parent | groupd id: 2934
+Child received: 46
+^CReceived signal: 2
+Stopping the program
+Received signal: 2
+Stopping the program
+finished
+Message during exit
+finished
+Message during exit
+
+whil kill parent
+Parent | id: 3396
+Parent | father id: 2610
+Parent | groupd id: 3396
+Child received: 10
+Parent | id: 3396
+Parent | father id: 2610
+Parent | groupd id: 3396
+Child received: 11
+Received signal: 15
+Stopping the program
+finished
+Message during exit
+
+with kill child
+Child received: 41
+Parent | id: 3644
+Parent | father id: 2610
+Parent | groupd id: 3644
+Child received: 42
+Received signal: 15
+Stopping the program
+finished
+Message during exit
+Child stopped, father stopping
+finished
+Message during exit
+
+*/
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