/* server2.c -- request-reply demo
 Compilation on cs:
 gcc -Wall -o server2 server2.c -lnsl -lsocket -lresolv
 */

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

#define BMAX 100
#define BACKLOG 5     // how many pending connections queue will hold

#define MESS "Hello, world!\015\012"

int main(int argc, char *argv[])
{
  int sockfd, new_fd;  // listen on sock_fd, new connection on new_fd
  struct sockaddr_in my_addr;    // my address information
  struct sockaddr_in their_addr; // connector's address information
  int sin_size, count, i, numbytes;
  int port = 5555;		// default port
  char yes='1';
  char buf[BMAX+1];

  if (argc > 1)
	  port = atoi(argv[1]);

  /* get & set up socket */
  if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) == -1) {
	  perror("socket");
	  exit(1);
  }

  if (setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(int)) == -1) {
	  perror("setsockopt");
	  exit(1);
  }

  /* construct local address struct */
  my_addr.sin_family = AF_INET;			// host byte order
  my_addr.sin_port = htons(port);		// short, network byte order
  my_addr.sin_addr.s_addr = INADDR_ANY;	// automatically fill with my IP
  memset(&(my_addr.sin_zero), '\0', 8);	// zero the rest of the struct

  /* bind to the port */
  if (bind(sockfd, (struct sockaddr *)&my_addr, sizeof(struct sockaddr)) == -1) {
	  perror("bind");
	  exit(1);
  }

  /* open port for connections */
  if (listen(sockfd, BACKLOG) == -1) {
	  perror("listen");
	  exit(1);
  }

  while(1) {  // main accept() loop
	  sin_size = sizeof(struct sockaddr_in);

	  /* accept new connection */
	  if ((new_fd = accept(sockfd, (struct sockaddr *)&their_addr, &sin_size)) == -1) {
		  perror("accept");
		  continue;
	  }
	  printf("server: got connection from %s\n",inet_ntoa(their_addr.sin_addr));

	  /* receive request */
	  if ((numbytes=recv(new_fd, buf, BMAX, 0)) == -1) {
		  perror("recv");
		  exit(1);
	  }
	  buf[numbytes] = '\0';	/* terminate string */

	  count = atoi(buf);		/* convert to int */

	  /* send count messages (lines) */
	  printf("%d\n", count);
	  for (i = 0; i < count; i++) {
		  if (send(new_fd, MESS, strlen(MESS), 0) == -1) {
			  /* you should also check for incomplete sends */
			  perror("send");
			  break;
		  }
	  }
	  close(new_fd);	/* close socket of one connection */
  }

  return 0;
}