CS473 - Computer Networks

Displaying exercises/e4/solution/say.c

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <time.h>

#define BUFSIZE	4096

#define K	1024

/*
 #define UNIX_PATH_MAX    108

 struct sockaddr_un {
   sa_family_t sun_family;		// AF_UNIX
   char sun_path[UNIX_PATH_MAX];	// pathname
 };
*/

int main(int argc, char *argv[])
{
  struct sockaddr_un name;
  char *sock_path = "/tmp/listen";
  char buf[K];
  int r;

  if (argc > 1) sock_path = argv[1];

  if (access(sock_path, W_OK) != 0) {
    printf("Unable to find socket file %s\n", sock_path);
    exit(0);
  }

  /* Create socket, initially un-connected. */
  int sock = socket(AF_UNIX, SOCK_DGRAM, 0);
  if (sock < 0) {
    perror("socket");
    exit(1);
  }

  /* Define name (filesystem socket file) to send to: */
  name.sun_family = AF_UNIX;
  strcpy(name.sun_path, sock_path);

  printf("Type Ctrl-D to quit:\n");
  while((r = read(STDIN_FILENO, buf, K)) > 0) {
    if (sendto(sock, buf, r, 0, (struct sockaddr *)&name,
	sizeof(struct sockaddr_un)) < 0) {
      perror("sendto");
      exit(1);
    }
  }
  close(sock);
  return 0;
}