Implement graceful shutdown

firewall-server/server.c

@@ -1,5 +1,33 @@
 #include <stdio.h>
 #include "sockets.c"
+#include <pthread.h>
+#include <signal.h>
+
+int sd;
+
+int run_server(const char **port_str) {
+    if (open_socket("127.0.0.1", *port_str, &sd) != 0) {
+        return 1;
+    }
+
+    if (accept_loop(sd) != 0) {
+        return 1;
+    }
+
+    return 0;
+}
+
+void sigint_handler(int) {
+    fprintf(stderr, "Gracefully shutting down...\n");
+
+    if (shutdown(sd, 2) != 0) {
+        perror("warning: global shutdown connection failed");
+    }
+
+    if (close(sd) != 0) {
+        perror("warning: global close connection failed");
+    }
+}
 
 int main (int argc, char **argv) {
     if (argc < 2) {
@@ -8,14 +36,21 @@ int main (int argc, char **argv) {
     }
     char *port_str = argv[1];
 
-    int sd;
-    if (open_socket("127.0.0.1", port_str, &sd) != 0) {
+    pthread_t thread_id;
+    pthread_create(
+            &thread_id,
+            NULL,
+            (void *) &run_server,
+            &port_str
+    );
+
+    signal(SIGINT, &sigint_handler);
+
+    int res, status;
+    if ((status = pthread_join(thread_id, (void *) &res)) != 0) {
+        fprintf(stderr, "join worker thread: %s\n", strerror(status));
         return 1;
     }
 
-    if (accept_loop(sd) != 0) {
-        return 1;
-    }
-    
-    return 0;
+    return res;
 }

firewall-server/sockets.c

@@ -8,6 +8,8 @@
 #include <stdio.h>
 #include <string.h>
 #include <unistd.h>
+#include <stdlib.h>
+#include <errno.h>
 
 int open_socket(const char *ip, const char *port, int *res_sd) {
     // get address info
@@ -68,6 +70,10 @@ int accept_loop(int sd) {
     while (1) {
         int new_sd = accept(sd, NULL, NULL);
         if (new_sd == -1) {
+            if (errno == EINVAL) {
+                // This is us shutting down and closing the socket (I hope)
+                return 0;
+            }
             perror("failed to accept new connection");
             return 1;
         }