/* tcp.master.c SJ */
/* gcc -Wall -o tcp.master tcp.master.c -lnsl -lsocket -lresolv */
/* usage: tcp.master hostname:port hostname:port ... */


#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 makeconnect(char *addr, int port);

int main(int argc, char **argv)
{
  int socks[100], sock;
  int slaves = 0;
  char **param, *colon;
  int i, k;

  char mesg1[100];

  param = argv+1;
  while (*param) {
	  if (colon = strchr(*param, ':')) {
		  *colon = '\0';
		  sock = makeconnect(*param, atoi(colon+1));
		  if (sock != -1)
			  socks[slaves++] = sock;
	  }
	  param++;
  }

  printf("got %d slaves\n", slaves);

  /* send request to each slave */

  for (i = 0; i < slaves; i++) {
	  k = rand()%5 + 1;
	  sprintf(mesg1, "%d\n", k);
	  sendall(socks[i], mesg1);
  }

  /* receive from all slaves */
  for (i = 0; i < slaves; i++) 
	  receiveandprintall(socks[i]);

  return 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 makeconnect(char *addr, int port)
{
  struct sockaddr_in slave_addr;
  int sock;
  struct hostent *host;

  host=gethostbyname(addr);
  if (!host) {
	  herror("gethostbyname");
	  return -1;
  }
  
  if ((sock = socket(AF_INET, SOCK_STREAM, 0)) == -1) {
	  perror("socket");
	  return -1;
  }
  slave_addr.sin_family = AF_INET;    // host byte order
  slave_addr.sin_port = htons(port);  // short, network byte order
  slave_addr.sin_addr = *(struct in_addr*)(host->h_addr); // copy address
  memset(&(slave_addr.sin_zero), '\0', 8);  // zero the rest of the struct

  if (connect(sock, (struct sockaddr *)&slave_addr,
			  sizeof(struct sockaddr)) == -1) {
	  perror("connect");
	  return -1;
  }

  return sock;
}