Thread: select server help

I took out all the junk and fixed it. I was the slopy write function. We had and still have massive power outage all over the east coast after that hurricane. My part of Jersey just got power back but no cable. I hope that anyone else on this forum/board that's also from the tri-state is OK.

Here's the working server. Only thing is the server handles connections seperately. So it wont echo one message to all. Now that I have it working that's the next step. I'm putting this up for a basis for other people trying to get a select server working.

Code:

 #include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <netdb.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>

int main(int argc, char *argv[]) {
fd_set master;
fd_set read_fds;

struct sockaddr_in serv_addr, cli_addr;
struct hostent *server;
int fdmax, i;
FD_ZERO(&master);
FD_ZERO(&read_fds);

	 if(argc < 3) {
	 printf("USAGE: %s + IP Address + Port No.\n", argv[0]);
	 exit(EXIT_FAILURE);
	 }

int sockfd = socket(AF_INET, SOCK_STREAM, 0);
	if(sockfd < 0) {
	printf("SOCKET(-1) error --> %s.\n", strerror(errno));
	exit(EXIT_FAILURE);
	}

int yes = 1;
int sockopt = setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(int));
	if(sockopt == -1) {
	printf("SETSOCKOPT(-1) error --> %s.\n", strerror(errno));
	exit(EXIT_FAILURE);
	}

server = gethostbyname(argv[1]); 
	if(server == NULL) {
	printf("GETHOSTBYNAME(NULL) error --> %s.\n", strerror(errno));
	exit(EXIT_FAILURE);
	}

int portno = atoi(argv[2]);
	if(portno < 0) {
	printf("ATOI(-1) error --> %s.\n", strerror(errno));
	exit(EXIT_FAILURE);
	}

	if(portno == 0) {
	printf("ATOI(0) - DEBUG MSG --> %s.\n", strerror(errno));
	}

serv_addr.sin_family = AF_INET;
serv_addr.sin_addr.s_addr = htonl(INADDR_ANY);
//memcpy(&serv_addr.sin_addr.s_addr, server->h_addr, server->h_length);
serv_addr.sin_port = htons(portno);
memset(&(serv_addr.sin_zero), '\0', 8);

//Bind() returns zero upon success.
int binder = bind(sockfd, (struct sockaddr *)&serv_addr, sizeof(serv_addr));
	if(binder < 0) {
	printf("BIND(-1) error --> %s.\n", strerror(errno));
	exit(EXIT_FAILURE);
	}

int listener = listen(sockfd, 10);
	if(listener < 0) {
	printf("Listen(-1) error --> %s.\n", strerror(errno));
	exit(EXIT_FAILURE);
	}
		//Listen() return zero upon success.
		else {
		printf("Listening for incoming connections.\n");
		}

FD_SET(sockfd, &master);
fdmax = sockfd; 

for( ; ; ) {
read_fds = master;
char buffer[4096];

int selector = select(fdmax+1, &read_fds, NULL, NULL, NULL);
	if(selector < 0) {
	printf("SELECT(-1) error --> %s.\n", strerror(errno));
	exit(EXIT_FAILURE);
	}

 for(i = 0; i <= fdmax; i++) {
	if(FD_ISSET(i, &read_fds)) {

	  if(i == sockfd) {
	  socklen_t clilen;
	  clilen = sizeof(cli_addr);

	  int newsockfd = accept(sockfd, (struct sockaddr *)&cli_addr, &clilen);
	    if(newsockfd < 0) {
	    printf("Accept(-1) error --> %s.\n", strerror(errno));
	    exit(EXIT_FAILURE);
	    }

	    if(newsockfd == 0) {
	    printf("ACCEPT(0) - DEBUG MSG --> %s.\n", strerror(errno));
	    }
	        
	    	else {
	    	  FD_SET(newsockfd, &master); 
	    	  if(newsockfd > fdmax) {
	    	  fdmax = newsockfd;
	    	  }
	
	    	printf("%s: New connection from %s on socket %d\n", argv[0], inet_ntoa(cli_addr.sin_addr), newsockfd);
	    	}
	  }
	
	  	else {
	  	ssize_t bytes_read = recv(i, buffer, sizeof(buffer), 0);
	  	if(bytes_read <= 0) {

	  	  if(bytes_read < 0) {
	  	  printf("RECV(-1) error --> %s.\n", strerror(errno));
	  	  exit(EXIT_FAILURE);
	  	  }

	  	  if(bytes_read == 0) {
	  	  printf("%s: socket %d hung up\n", argv[0], i);
	  	  FD_CLR(i, &master);
	  	  close(i);
	  	  }

	  	}

	  		else if(bytes_read) {
	  		printf("Recieve was successful.\n");
	  		ssize_t bytes_written = write(i, buffer, strlen(buffer));
	  		  if(bytes_written < 0) {
	  		  printf("WRITE(-1) error ---> %s.\n", strerror(errno));
	  		  }

	  		  if(bytes_written == 0) {
	  		  printf("Nothing was written.\n");
	  		  }

	  		  if(bytes_written) {
	  		  printf("Write was successful.\n");
                          memset(buffer, '\0', strlen(buffer));
	  		  }

	  		}

	  	}
	}
 }
}

return 0;
}