Server in the connection-oriented service

The following server program for the connection-oriented service is described in detail in section "Connection-oriented client/server model". The server sets up a transport connection to a client and then passes a protocol file to this client. The connection is shut down using the orderly connection shutdown of the transport interface. The client in the connection-oriented service described in the previous section can communicate with the server described here.

#include <xti.h>
#include <stropts.h>
#include <fcntl.h>
#include <stdio.h>
#include <netinet/in.h>
#include <sys/socket.h>
#define FILENAME "/etc/services"
#define DISCONNECT -1
#define SRV_ADDR 0x7F000001
#define SRV_PORT 8888
int conn_fd;  /* Connection setup */
main()
{
   int listen_fd;  /* Monitor transport endpoint */
   struct t_bind *bind;
   struct t_call *call;
   struct sockaddr_in *sin;
   if ((listen_fd = t_open("/dev/tcp", O_RDWR, NULL)) < 0) {
      t_error("t_open() failed for listen_fd");
      exit(1);
   }
   if ((bind = (struct t_bind *)t_alloc(listen_fd,T_BIND, T_ALL)) == NULL) {
      t_error("t_alloc() of the t_bind structure failed");
      exit(2);
   }
   bind->qlen = 1;
   bind->addr.len=sizeof(struct sockaddr_in);
   sin = (struct sockaddr_in *)bind->addr.buf;
   sin->sin_family=AF_INET;
   sin->sin_port=htons(SRV_PORT);
   sin->sin_addr.s_addr=htonl(SRV_ADDR);
   if (t_bind(listen_fd, bind, bind) < 0) {
      t_error("t_bind() for listen_fd failed");
      exit(3);
   }
   if ((call = (struct t_call *)t_alloc(listen_fd,T_CALL, T_ALL)) == NULL) {
      t_error("t_alloc() of t_call structure failed");
      exit(5);
   }
   for(;;) {
      if (t_listen(listen_fd, call) < 0) {
         t_error("t_listen() for listen_fd failed");
         exit(6);
      }
      if ((conn_fd = accept_call(listen_fd, call)) != DISCONNECT) 
         run_server(listen_fd);
   }
}
accept_call(listen_fd, call)
int listen_fd;
struct t_call *call;
{
   int resfd;
   struct t_call *refuse_call;
   if ((resfd = t_open("/dev/tcp", O_RDWR, NULL)) < 0) {
      t_error("t_open() for responding fd failed");
      exit(7);
   }
   while (t_accept(listen_fd, resfd, call) < 0) {
      if (t_errno == TLOOK) {
         if (t_look(listen_fd) == T_DISCONNECT) { /* Connection abort */
              if (t_rcvdis(listen_fd, NULL) < 0) {
                 t_error("t_rcvdis() failed for listen_fd");
                 exit(9);
              }
              if (t_close(resfd) < 0) {
                 t_error("t_close failed for responding fd");
                 exit(10);
              } 
              /* Terminate call and wait for further call */
              return(DISCONNECT);
         } else { /* New T_LISTEN; delete event */
              if ((refuse_call = 
                 (struct t_call*)t_alloc(listen_fd,T_CALL,0)) == NULL) {
                 t_error("t_alloc() for refuse_call failed");
                 exit(11);
              }
              if (t_listen(listen_fd, refuse_call) < 0) {
                 t_error("t_listen() for refuse_call failed");
                 exit(12);
              }
              if (t_snddis(listen_fd, refuse_call) < 0) {
                 t_error("t_snddis() for refuse_call failed");
                 exit(13);
              }
              if (t_free((char *)refuse_call, T_CALL) < 0) {
                 t_error("t_free() for refuse_call failed");
                 exit(14);
              }
         }
      } else {
         t_error("t_accept() failed");
         exit(15);
      }
   }
   return(resfd);
}
run_server(listen_fd)
int listen_fd;
{
   int nbytes;
   FILE *logfp; /* File pointer to log file */
   char buf[1024];
   switch (fork()) {
   case -1:
      perror("fork failed");
      exit(20);
      break;
   default: /* Parent process */
      /* Close conn_fd and remain active as monitor again */
      if (t_close(conn_fd) < 0) {
         t_error("t_close() for conn_fd failed");
         exit(21);
      }
      return;
   case 0:  /* Child */
      /* Close listen_fd and execute service */
      if (t_close(listen_fd) < 0) {
         t_error("t_close() for listen_fd failed");
         exit(22);
      }
      if ((logfp = fopen(FILENAME, "r")) == NULL) {
         perror("Log file cannot be opened");
         exit(23);
      }
      if (t_look(conn_fd) != 0) { /* Was there an interruption? */
         fprintf(stderr, "t_look: unexpected event\n");
         exit(25);
      }
      while ((nbytes = fread(buf, 1, 1024, logfp)) > 0)
         if (t_snd(conn_fd, buf, nbytes, 0) < 0) {
            t_error("t_snd() failed");
            exit(26);
         }
      if (t_sndrel(conn_fd) < 0) {
         t_error("t_sndrel() failed");
         exit(27);
      }
      while(t_look(conn_fd) == 0) {
         sleep(1);
      }
      if(t_look(conn_fd) == T_DISCONNECT) {
         fprintf(stderr, "Connection aborted\n");
         exit(12);
      }
      exit(0);
   }
}