/* tcp.slave.c SJ */
/* gcc -Wall -o tcp.slave tcp.slave.c -lnsl -lsocket -lresolv
*/

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

void sendall(int sock, char *buf);
void receiveandprintall(int sock);
int waitconnect(int port);

int main(int argc, char **argv)
{
  int j;
  int numbytes, count;

  char buf[1000];
  char mesg2[100];
  char hname[100];

  struct sockaddr_in remote_addr, my_addr;
  int sock, newsock;
  int sin_size;
  char yes='1';
  
  if ((sock = socket(AF_INET, SOCK_STREAM, 0)) == -1) {
	  perror("socket");
	  exit(1);
  }

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

  if (gethostname(hname, 99) == -1) {
	  perror("gethostname");
	  strcpy(hname, "???");
  }

  my_addr.sin_family = AF_INET;    // host byte order
  my_addr.sin_port = htons(atoi(argv[1]));  // 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(sock, (struct sockaddr *)&my_addr, sizeof(struct sockaddr)) == -1) {                perror("bind");
	  exit(1);
  }

  /* open port for connections */
  if (listen(sock, 2) == -1) {
	  perror("listen");
	  exit(1);
  }

  while(1) {
	  sin_size = sizeof(struct sockaddr_in);

	  /* accept new connection */
	  if ((newsock = accept(sock, (struct sockaddr *)&remote_addr, &sin_size)) == -1) {
		  perror("accept");
		  continue;
	  }

	  printf("got connection from %s\n",inet_ntoa(remote_addr.sin_addr));
	  if ((numbytes=recv(newsock, buf, 999, 0)) == -1) {
		  perror("recv");
		  close(newsock);
		  continue;
	  }
	  buf[numbytes] = '\0';   /* terminate string */

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

	  puts(buf);

	  if (count < 1) {
		  close(newsock);
		  break;
	  }

	  sprintf(mesg2, "Hello from %s(pid=%d)\n", hname, getpid());
	  for (j = 0; j < count; j++) {
		  sendall(newsock, mesg2);
	  }

	  close(newsock);
  }

  close(sock);

  exit(0);

}


void sendall(int sock, char *buf)
{
  int len, bs;
  len = strlen(buf);
  while (len > 0) {
	  bs = send(sock, buf, len, 0);
	  if (bs == -1) {
		  perror("send");
		  return;
	  } else if (bs == 0) {
		  printf("Connection closed prematurely\n");
		  return;
	  }

	  len -= bs;
  }
} /* sendall() */

void receiveandprintall(int sock)
{
  int numbytes;
  char buf[1000];

  while ((numbytes = recv(sock, buf, 1000-1, 0))) {
	  if (numbytes == -1) {
		  perror("recv");
		  exit(1);
	  }
	  buf[numbytes] = '\0';   /* terminate string */
	  fputs(buf, stdout);
  }

  close(sock);
}

/* returns socket */
int waitconnect(int port)
{
  struct sockaddr_in remote_addr, my_addr;
  int sock, newsock;
  int sin_size;
  
  if ((sock = socket(AF_INET, SOCK_STREAM, 0)) == -1) {
	  perror("socket");
	  exit(1);
  }
  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(sock, (struct sockaddr *)&my_addr, sizeof(struct sockaddr)) == -1) {                perror("bind");
	  exit(1);
  }

  /* open port for connections */
  if (listen(sock, 2) == -1) {
	  perror("listen");
	  exit(1);
  }

  sin_size = sizeof(struct sockaddr_in);

  /* accept new connection */
  if ((newsock = accept(sock, (struct sockaddr *)&remote_addr, &sin_size)) == -1) {
	  perror("accept");
  }

  /* stop listening */
  close(sock);

  return newsock;
}