Server with poll()

SinghCoder · SinghCoder · commit bbd2aa2ef4bd · 2020-04-07T20:33:34.000+05:30
diff --git a/Exercises/Exercise5/poll_n_server.c b/Exercises/Exercise5/poll_n_server.c
@@ -0,0 +1,96 @@
+#include "poll_n_server.h"
+#include <stdio.h>
+#include <stdlib.h>
+#include "poll.h"
+#include <sys/socket.h>
+#include <netinet/in.h>
+
+
+int main(int argc, char *argv[])
+{
+    if(argc < 2){
+        printf("Usage: %s N\n", argv[0]);
+        exit(EXIT_FAILURE);
+    }
+
+    int num_of_clients = atoi(argv[1]); 
+
+    struct sockaddr_in client_addr, server_addr;
+
+    int listen_sockfd, conn_sockfd, client_sockfd;
+
+    struct pollfd poll_fds[num_of_clients + 1]; // 1 for listen_sockfd
+
+    int curr_cli_count = 0;
+
+    for(int i = 0; i < num_of_clients; i++){
+        poll_fds[i].fd = -1;
+        poll_fds[i].events = POLLIN;
+    }
+
+    poll_fds[num_of_clients].fd = listen_sockfd;
+    poll_fds[num_of_clients].events = POLLIN;
+
+    listen_sockfd = socket(AF_INET, SOCK_STREAM, 0);
+    bzero(&server_addr, sizeof(struct sockaddr_in));
+
+    server_addr.sin_family = AF_INET;
+    server_addr.sin_port = htons(SERVER_PORT);
+    server_addr.sin_addr.s_addr = inet_addr("127.0.0.1");
+
+    bind(listen_sockfd, (struct sockaddr *)&server_addr, sizeof(server_addr));
+    listen(listen_sockfd, MAX_QUEUE_SIZE);
+
+    int poll_status;
+    int num_ready = 0;
+
+    for( ; ; ){
+        poll_status = poll(poll_fds, num_of_clients, TIMEOUT_MS);
+
+        if(poll_status == -1){
+            perror("poll");
+            exit(EXIT_FAILURE);
+        }
+
+        if(poll_status == 0){
+            printf("Timeout occured\n");
+            return 0;
+        }
+
+        num_ready = poll_status;
+
+        if(poll_fds[num_of_clients].revents & POLLIN)  // listening socket is readable
+            conn_sockfd = accept(listen_sockfd, (struct sockaddr *)&client_addr, sizeof(client_addr));
+        
+        int i;
+
+        for(i = 0; i < num_of_clients; i++){
+            if(poll_fds[i].fd == -1){
+                poll_fds[i].fd = conn_sockfd;
+                break;
+            }
+        }
+
+        if(i == num_of_clients){
+            printf("Number of clients exceeded %d\n", num_of_clients);
+            exit(EXIT_FAILURE);
+        }
+
+        if(--num_ready <= 0){
+            continue;   // no more readable clients
+        }
+
+        for(i = 0; i < num_of_clients; i++){
+            if(poll_fds[i].revents & POLLIN){
+                // send data to all other clients
+                for(int j = 0; j < num_of_clients; j++){
+                    if(j != i){
+                        // send(poll_fds[i].fd,)
+                    }
+                }
+            }
+        }
+    }
+
+    return 0;
+}
diff --git a/Exercises/Exercise5/poll_n_server.h b/Exercises/Exercise5/poll_n_server.h
@@ -0,0 +1,8 @@
+#ifndef POLL_N_SERVER_H
+#define POLL_N_SERVER_H
+
+#define SERVER_PORT 5000
+#define MAX_QUEUE_SIZE 100
+#define TIMEOUT_MS 5000
+
+#endif
