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[unix-history] / usr / src / usr.bin / talk / ctl_transact.c

#ifndef lint
static char sccsid[] = "@(#)ctl_transact.c      1.2 (Berkeley) %G%";
#endif

#include "talk_ctl.h"
#include <sys/time.h>

#define CTL_WAIT 2      /* time to wait for a response, in seconds */

/*
* SOCKDGRAM is unreliable, so we must repeat messages if we have
* not recieved an acknowledgement within a reasonable amount
* of time
*/
ctl_transact(target, msg, type, response)
       struct in_addr target;
       CTL_MSG msg;
       int type;
       CTL_RESPONSE *response;
{
       struct sockaddr junk;
       int read_mask;
       int ctl_mask;
       int nready;
       int cc;
       int junk_size;
       struct timeval wait;

       wait.tv_sec = CTL_WAIT;
       wait.tv_usec = 0;
       msg.type = type;
       daemon_addr.sin_addr = target;
       daemon_addr.sin_port = daemon_port;
       ctl_mask = 1 << ctl_sockt;

       /*
        * keep sending the message until a response of the right
        * type is obtained
        */
       do {
               /* keep sending the message until a response is obtained */
               do {
                       cc = sendto(ctl_sockt, (char *)&msg, sizeof(CTL_MSG), 0,
                               &daemon_addr, sizeof(daemon_addr));
                       if (cc != sizeof(CTL_MSG)) {
                               if (errno == EINTR)
                                       continue;
                               p_error("Error on write to talk daemon");
                       }
                       read_mask = ctl_mask;
                       nready = select(32, &read_mask, 0, 0, &wait);
                       while (nready < 0) {
                               if (errno == EINTR)
                                       continue;
                               p_error("Error waiting for daemon response");
                       }
               } while (nready == 0);
               /* keep reading while there are queued messages 
                  (this is not necessary, it just saves extra
                  request/acknowledgements being sent)
                */
               do {
                       junk_size = sizeof(junk);
                       cc = recvfrom(ctl_sockt, (char *)response,
                           sizeof (CTL_RESPONSE), 0, &junk, &junk_size);
                       if (cc < 0) {
                               if (errno == EINTR)
                                       continue;
                               p_error("Error on read from talk daemon");
                       }
                       read_mask = ctl_mask;
                       /* an immediate poll */
                       timerclear(&wait);
                       nready = select(32, &read_mask, 0, 0, &wait);
               } while (nready > 0 && response->type != type);
       } while (response->type != type);
}