ctl_transact.c revision 90868 
1/*
2 * Copyright (c) 1983, 1993
3 *	The Regents of the University of California.  All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 * 3. All advertising materials mentioning features or use of this software
14 *    must display the following acknowledgement:
15 *	This product includes software developed by the University of
16 *	California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 *    may be used to endorse or promote products derived from this software
19 *    without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 */
33
34#include <sys/cdefs.h>
35
36__FBSDID("$FreeBSD: head/usr.bin/talk/ctl_transact.c 90868 2002-02-18 20:35:27Z mike $");
37
38#ifndef lint
39static const char sccsid[] = "@(#)ctl_transact.c	8.1 (Berkeley) 6/6/93";
40#endif
41
42#include <arpa/inet.h>
43
44#include <errno.h>
45#include <string.h>
46
47#include "talk.h"
48#include "talk_ctl.h"
49
50#define CTL_WAIT 2	/* time to wait for a response, in seconds */
51
52/*
53 * SOCKDGRAM is unreliable, so we must repeat messages if we have
54 * not recieved an acknowledgement within a reasonable amount
55 * of time
56 */
57void
58ctl_transact(target, lmsg, type, rp)
59	struct in_addr target;
60	CTL_MSG lmsg;
61	int type;
62	CTL_RESPONSE *rp;
63{
64	fd_set read_mask, ctl_mask;
65	int nready = 0, cc;
66	struct timeval wait;
67
68	lmsg.type = type;
69	daemon_addr.sin_addr = target;
70	daemon_addr.sin_port = daemon_port;
71	FD_ZERO(&ctl_mask);
72	FD_SET(ctl_sockt, &ctl_mask);
73
74	/*
75	 * Keep sending the message until a response of
76	 * the proper type is obtained.
77	 */
78	do {
79		wait.tv_sec = CTL_WAIT;
80		wait.tv_usec = 0;
81		/* resend message until a response is obtained */
82		do {
83			cc = sendto(ctl_sockt, (char *)&lmsg, sizeof (lmsg), 0,
84			    (struct sockaddr *)&daemon_addr,
85			    sizeof (daemon_addr));
86			if (cc != sizeof (lmsg)) {
87				if (errno == EINTR)
88					continue;
89				p_error("Error on write to talk daemon");
90			}
91			read_mask = ctl_mask;
92			nready = select(32, &read_mask, 0, 0, &wait);
93			if (nready < 0) {
94				if (errno == EINTR)
95					continue;
96				p_error("Error waiting for daemon response");
97			}
98		} while (nready == 0);
99		/*
100		 * Keep reading while there are queued messages
101		 * (this is not necessary, it just saves extra
102		 * request/acknowledgements being sent)
103		 */
104		do {
105			cc = recv(ctl_sockt, (char *)rp, sizeof (*rp), 0);
106			if (cc < 0) {
107				if (errno == EINTR)
108					continue;
109				p_error("Error on read from talk daemon");
110			}
111			read_mask = ctl_mask;
112			/* an immediate poll */
113			timerclear(&wait);
114			nready = select(32, &read_mask, 0, 0, &wait);
115		} while (nready > 0 && (rp->vers != TALK_VERSION ||
116		    rp->type != type));
117	} while (rp->vers != TALK_VERSION || rp->type != type);
118	rp->id_num = ntohl(rp->id_num);
119	rp->addr.sa_family = ntohs(rp->addr.sa_family);
120}
121