Suppose, I have a connected
socket after writing this code..
if ((sd = accept(socket_d, (struct sockaddr *)&client_addr, &alen)) < 0)
{
perror("accept failed\n");
exit(1);
}
How can I know at the server side that
client has exited.
My whole program actually does the following..
Accepts a connection from
client
Starts a new thread that reads messages from that particular
client and then broadcast this message to all the connected clients.
If you want to see the whole code... In this whole code. I am also struggling with one more problem that whenever I kill a
client with Ctrl+C, my server terminates abruptly.. It would be nice if anyone could suggest what the problem is..
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <signal.h>
#include <errno.h>
#include <pthread.h>
/*CONSTANTS*/
#define DEFAULT_PORT 10000
#define LISTEN_QUEUE_LIMIT 6
#define TOTAL_CLIENTS 10
#define CHAR_BUFFER 256
/*GLOBAL VARIABLE*/
int current_client = 0;
int connected_clients[TOTAL_CLIENTS];
extern int errno;
void *client_handler(void * socket_d);
int main(int argc, char *argv[])
{
struct sockaddr_in server_addr;/* structure to hold server's address*/
int socket_d; /* listening
socket descriptor */
int port; /* protocol port number */
int option_value; /* needed for setsockopt */
pthread_t tid[TOTAL_CLIENTS];
port = (argc > 1)?atoi(argv[1]):DEFAULT_PORT;
/*
Socket Server address structure */
memset((char *)&server_addr, 0, sizeof(server_addr));
server_addr.sin_family = AF_INET; /* set family to Internet */
server_addr.sin_addr.s_addr = INADDR_ANY; /* set the local IP address */
server_addr.sin_port = htons((u_short)port); /* Set port */
/* Create
socket */
if ( (socket_d = socket(PF_INET, SOCK_STREAM, 0)) < 0) {
fprintf(stderr, "
socket creation failed\n");
exit(1);
}
/* Make listening
socket's port reusable */
if (setsockopt(socket_d, SOL_SOCKET, SO_REUSEADDR, (char *)&option_value,
sizeof(option_value)) < 0) {
fprintf(stderr, "setsockopt failure\n");
exit(1);
}
/* Bind a local address to the
socket */
if (bind(socket_d, (struct sockaddr *)&server_addr, sizeof(server_addr)) < 0) {
fprintf(stderr, "bind failed\n");
exit(1);
}
/* Specify size of request queue */
if (listen(socket_d, LISTEN_QUEUE_LIMIT) < 0) {
fprintf(stderr, "listen failed\n");
exit(1);
}
memset(connected_clients,0,sizeof(int)*TOTAL_CLIENTS);
for (;;)
{
struct sockaddr_in client_addr; /* structure to hold
client's address*/
int alen = sizeof(client_addr); /* length of address */
int sd; /* connected
socket descriptor */
if ((sd = accept(socket_d, (struct sockaddr *)&client_addr, &alen)) < 0)
{
perror("accept failed\n");
exit(1);
}
else printf("\n I got a connection from (%s , %d)\n",inet_ntoa(client_addr.sin_addr),ntohs(client_addr.sin_port));
if (pthread_create(&tid[current_client],NULL,(void *)client_handler,(void *)sd) != 0)
{
perror("pthread_create error");
continue;
}
connected_clients[current_client]=sd;
current_client++; /*Incrementing
Client number*/
}
return 0;
}
void *client_handler(void *connected_socket)
{
int sd;
sd = (int)connected_socket;
for ( ; ; )
{
ssize_t n;
char buffer[CHAR_BUFFER];
for ( ; ; )
{
if (n = read(sd, buffer, sizeof(char)*CHAR_BUFFER) == -1)
{
perror("Error reading from
client");
pthread_exit(1);
}
int i=0;
for (i=0;i<current_client;i++)
{
if (write(connected_clients[i],buffer,sizeof(char)*CHAR_BUFFER) == -1)
perror("Error sending messages to a
client while multicasting");
}
}
}
}
My
client side is this (Maye be irrelevant while answering my question)
#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
#include <string.h>
#include <stdlib.h>
void error(char *msg)
{
perror(msg);
exit(0);
}
void *listen_for_message(void * fd)
{
int sockfd = (int)fd;
int n;
char buffer[256];
bzero(buffer,256);
printf("YOUR MESSAGE: ");
fflush(stdout);
while (1)
{
n = read(sockfd,buffer,256);
if (n < 0)
error("ERROR reading from
socket");
if (n == 0) pthread_exit(1);
printf("\nMESSAGE BROADCAST: %sYOUR MESSAGE: ",buffer);
fflush(stdout);
}
}
int main(int argc, char *argv[])
{
int sockfd, portno, n;
struct sockaddr_in serv_addr;
struct hostent *server;
pthread_t read_message;
char buffer[256];
if (argc < 3) {
fprintf(stderr,"usage %s hostname port\n", argv[0]);
exit(0);
}
portno = atoi(argv[2]);
sockfd = socket(AF_INET, SOCK_STREAM, 0);
if (sockfd < 0)
error("ERROR opening
socket");
server = gethostbyname(argv[1]);
if (server == NULL) {
fprintf(stderr,"ERROR, no such host\n");
exit(0);
}
bzero((char *) &serv_addr, sizeof(serv_addr));
serv_addr.sin_family = AF_INET;
bcopy((char *)server->h_addr,
(char *)&serv_addr.sin_addr.s_addr,
server->h_length);
serv_addr.sin_port = htons(portno);
if (connect(sockfd,&serv_addr,sizeof(serv_addr)) < 0)
error("ERROR connecting");
bzero(buffer,256);
if (pthread_create(&read_message,NULL,(void *)listen_for_message,(void *)sockfd) !=0 )
{
perror("error creating thread");
}
while (1)
{
fgets(buffer,255,stdin);
n = write(sockfd,buffer,256);
if (n < 0)
error("ERROR writing to
socket");
bzero(buffer,256);
}
return 0;
}
