ctl_transact.c revision 178642 
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 178642 2008-04-28 21:08:42Z delphij $");
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(struct in_addr target, CTL_MSG lmsg, int type, CTL_RESPONSE *rp)
59{
60	fd_set read_mask, ctl_mask;
61	int nready = 0, cc;
62	struct timeval wait;
63
64	lmsg.type = type;
65	daemon_addr.sin_addr = target;
66	daemon_addr.sin_port = daemon_port;
67	FD_ZERO(&ctl_mask);
68	FD_SET(ctl_sockt, &ctl_mask);
69
70	/*
71	 * Keep sending the message until a response of
72	 * the proper type is obtained.
73	 */
74	do {
75		wait.tv_sec = CTL_WAIT;
76		wait.tv_usec = 0;
77		/* resend message until a response is obtained */
78		do {
79			cc = sendto(ctl_sockt, (char *)&lmsg, sizeof (lmsg), 0,
80			    (struct sockaddr *)&daemon_addr,
81			    sizeof (daemon_addr));
82			if (cc != sizeof (lmsg)) {
83				if (errno == EINTR)
84					continue;
85				p_error("Error on write to talk daemon");
86			}
87			read_mask = ctl_mask;
88			nready = select(32, &read_mask, 0, 0, &wait);
89			if (nready < 0) {
90				if (errno == EINTR)
91					continue;
92				p_error("Error waiting for daemon response");
93			}
94		} while (nready == 0);
95		/*
96		 * Keep reading while there are queued messages
97		 * (this is not necessary, it just saves extra
98		 * request/acknowledgements being sent)
99		 */
100		do {
101			cc = recv(ctl_sockt, (char *)rp, sizeof (*rp), 0);
102			if (cc < 0) {
103				if (errno == EINTR)
104					continue;
105				p_error("Error on read from talk daemon");
106			}
107			read_mask = ctl_mask;
108			/* an immediate poll */
109			timerclear(&wait);
110			nready = select(32, &read_mask, 0, 0, &wait);
111		} while (nready > 0 && (rp->vers != TALK_VERSION ||
112		    rp->type != type));
113	} while (rp->vers != TALK_VERSION || rp->type != type);
114	rp->id_num = ntohl(rp->id_num);
115	rp->addr.sa_family = ntohs(rp->addr.sa_family);
116}
117