ADD: server with single connection, random fixes

.gitignore

@@ -1 +1,2 @@
 server
+server_sc

Makefile

@@ -6,5 +6,8 @@ default: server
 server: server.cpp
 	$(CC) $(CFLAGS) -o server server.cpp
 
+server_sc: server_single_connect.cpp
+	$(CC) $(CFLAGS) -o server_sc server_single_connect.cpp
+
 clean:
-	rm -f server
+	rm -f server server_sc

README.md

@@ -0,0 +1,23 @@
+# Build
+
+Build the server
+
+~~~bash
+$ make server
+~~~
+
+Build the server that accepts only a single connection at a time
+
+~~~bash
+$ make server_sc
+~~~
+
+# Connecting to the server
+
+~~~bash
+$ php client.php Hi
+~~~
+
+# References
+- http://www.binarytides.com/php-socket-programming-tutorial/
+- https://github.com/zappala/socket-programming-examples-c

server.cpp

@@ -28,10 +28,8 @@ int main(int argc, char **argv)
 {
   struct sockaddr_un server_addr, client_addr;
   socklen_t clientlen = sizeof(client_addr);
-  int client, buflen, nread, initCommResult;
+  int client, buflen, nread;
   char *buf;
-  char c;
-  int reuse = 1;
 
   puts("Hell World");
 
@@ -52,13 +50,6 @@ int main(int argc, char **argv)
     exit(-1);
   }
 
-  // set socket to immediately reuse port when the application closes
-  reuse = 1;
-  if (setsockopt(server, SOL_SOCKET, SO_REUSEADDR, &reuse, sizeof(reuse)) < 0) {
-    perror("setsockopt");
-    exit(-1);
-  }
-
   // call bind to associate the socket with our local address and
   // port
   if (bind(server, (const struct sockaddr *)&server_addr, sizeof(server_addr)) < 0) {
@@ -96,5 +87,7 @@ int main(int argc, char **argv)
 
   close(server);
 
-  return 0;
+  unlink(SOCKET_FILENAME);
+
+return 0;
 }

server_single_connect.cpp

@@ -0,0 +1,109 @@
+#include <arpa/inet.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <unistd.h>
+#include <signal.h>
+
+using namespace std;
+
+#define SOCKET_FILENAME "/tmp/server.sock"
+
+int server;
+
+void bind_listen_socket(int &server, sockaddr_un &server_addr)
+{
+  // create socket
+  server = socket(PF_UNIX, SOCK_STREAM, 0);
+  if (!server) {
+    perror("socket");
+    exit(-1);
+  }
+
+  // call bind to associate the socket with our local address and
+  // port
+  if (bind(server, (const struct sockaddr *)&server_addr, sizeof(server_addr)) < 0) {
+    perror("bind");
+    exit(-1);
+  }
+
+  // convert the socket to listen for incoming connections
+  if (listen(server, 0) < 0) {
+    perror("listen");
+    exit(-1);
+  }
+
+  puts("Listening to connection...");
+
+}
+
+void signal_callback_handler(int signum)
+{
+  // close server
+  close(server);
+  // remove the socket file
+  unlink(SOCKET_FILENAME);
+  // signal handled
+  exit(0);
+}
+
+int main(int argc, char **argv)
+{
+  struct sockaddr_un server_addr, client_addr;
+  socklen_t clientlen = sizeof(client_addr);
+  int client, buflen, nread;
+  char *buf;
+
+  puts("Hell World");
+
+  // listen to SIGINT, SIGTERM, and SIGKILL
+  signal(SIGINT, signal_callback_handler);
+  signal(SIGTERM, signal_callback_handler);
+  signal(SIGKILL, signal_callback_handler);
+
+  // setup socket address structure
+  memset(&server_addr, 0, sizeof(server_addr));
+  server_addr.sun_family = AF_UNIX;
+  strcpy(server_addr.sun_path, SOCKET_FILENAME);
+
+  // bind and listen on the socket file
+  bind_listen_socket(server, server_addr);
+
+  // allocate buffer
+  buflen = 1024;
+  buf = new char[buflen+1];
+
+  // loop to handle all requests
+  while (1) {
+    unsigned int client = accept(server, (struct sockaddr *)&client_addr, &clientlen);
+
+    // got a request, close the socket
+    close(server);
+    unlink(SOCKET_FILENAME);
+
+    // read a request
+    memset(buf, 0, buflen);
+    nread = recv(client, buf, buflen, 0);
+
+    printf("\nClient says: %s\n\n", buf);
+
+    // echo back to the client
+    send(client, buf, nread, 0);
+
+    close(client);
+
+    sleep(2);
+
+    // re-bind and listen on the socket
+    bind_listen_socket(server, server_addr);
+  }
+
+  close(server);
+
+  unlink(SOCKET_FILENAME);
+
+  return 0;
+}