4.3BSD - /usr/src/old/talk/ctl_transact.c

   1: /*
   2:  * Copyright (c) 1983 Regents of the University of California.
   3:  * All rights reserved.  The Berkeley software License Agreement
   4:  * specifies the terms and conditions for redistribution.
   5:  */
   6: 
   7: #ifndef lint
   8: static char sccsid[] = "@(#)ctl_transact.c	5.1 (Berkeley) 6/6/85";
   9: #endif not lint
  10: 
  11: #include "talk_ctl.h"
  12: #include <sys/time.h>
  13: 
  14: #define CTL_WAIT 2  /* time to wait for a response, in seconds */
  15: 
  16: /*
  17:  * SOCKDGRAM is unreliable, so we must repeat messages if we have
  18:  * not recieved an acknowledgement within a reasonable amount
  19:  * of time
  20:  */
  21: ctl_transact(target, msg, type, response)
  22:     struct in_addr target;
  23:     CTL_MSG msg;
  24:     int type;
  25:     CTL_RESPONSE *response;
  26: {
  27:     struct sockaddr junk;
  28:     int read_mask;
  29:     int ctl_mask;
  30:     int nready;
  31:     int cc;
  32:     int junk_size;
  33:     struct timeval wait;
  34: 
  35:     msg.type = type;
  36:     daemon_addr.sin_addr = target;
  37:     daemon_addr.sin_port = daemon_port;
  38:     ctl_mask = 1 << ctl_sockt;
  39: 
  40:     /*
  41: 	 * keep sending the message until a response of the right
  42: 	 * type is obtained
  43: 	 */
  44:     do {
  45:         wait.tv_sec = CTL_WAIT;
  46:         wait.tv_usec = 0;
  47: 
  48:         /* keep sending the message until a response is obtained */
  49:         do {
  50:             cc = sendto(ctl_sockt, (char *)&msg, sizeof(CTL_MSG), 0,
  51:                 &daemon_addr, sizeof(daemon_addr));
  52:             if (cc != sizeof(CTL_MSG)) {
  53:                 if (errno == EINTR)
  54:                     continue;
  55:                 p_error("Error on write to talk daemon");
  56:             }
  57:             read_mask = ctl_mask;
  58:             if ((nready = select(32, &read_mask, 0, 0, &wait)) < 0) {
  59:                 if (errno == EINTR)
  60:                     continue;
  61:                 p_error("Error waiting for daemon response");
  62:             }
  63:         } while (nready == 0);
  64:         /* keep reading while there are queued messages
  65: 		   (this is not necessary, it just saves extra
  66: 		   request/acknowledgements being sent)
  67: 		 */
  68:         do {
  69:             junk_size = sizeof(junk);
  70:             cc = recvfrom(ctl_sockt, (char *)response,
  71:                 sizeof (CTL_RESPONSE), 0, &junk, &junk_size);
  72:             if (cc < 0) {
  73:                 if (errno == EINTR)
  74:                     continue;
  75:                 p_error("Error on read from talk daemon");
  76:             }
  77:             read_mask = ctl_mask;
  78:             /* an immediate poll */
  79:             timerclear(&wait);
  80:             nready = select(32, &read_mask, 0, 0, &wait);
  81:         } while (nready > 0 && response->type != type);
  82:     } while (response->type != type);
  83: }

Defined functions

Defined variables

Defined macros