xref: /freebsd/usr.bin/talk/ctl_transact.c (revision 42249ef2)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1983, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. Neither the name of the University nor the names of its contributors
16  *    may be used to endorse or promote products derived from this software
17  *    without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  */
31 
32 #include <sys/cdefs.h>
33 
34 __FBSDID("$FreeBSD$");
35 
36 #ifndef lint
37 static const char sccsid[] = "@(#)ctl_transact.c	8.1 (Berkeley) 6/6/93";
38 #endif
39 
40 #include <arpa/inet.h>
41 
42 #include <errno.h>
43 #include <poll.h>
44 
45 #include "talk.h"
46 #include "talk_ctl.h"
47 
48 #define CTL_WAIT 2	/* time to wait for a response, in seconds */
49 
50 /*
51  * SOCKDGRAM is unreliable, so we must repeat messages if we have
52  * not received an acknowledgement within a reasonable amount
53  * of time
54  */
55 void
56 ctl_transact(struct in_addr target, CTL_MSG lmsg, int type, CTL_RESPONSE *rp)
57 {
58 	struct pollfd pfd[1];
59 	int nready = 0, cc;
60 
61 	lmsg.type = type;
62 	daemon_addr.sin_addr = target;
63 	daemon_addr.sin_port = daemon_port;
64 	pfd[0].fd = ctl_sockt;
65 	pfd[0].events = POLLIN;
66 
67 	/*
68 	 * Keep sending the message until a response of
69 	 * the proper type is obtained.
70 	 */
71 	do {
72 		/* resend message until a response is obtained */
73 		do {
74 			cc = sendto(ctl_sockt, (char *)&lmsg, sizeof (lmsg), 0,
75 			    (struct sockaddr *)&daemon_addr,
76 			    sizeof (daemon_addr));
77 			if (cc != sizeof (lmsg)) {
78 				if (errno == EINTR)
79 					continue;
80 				p_error("Error on write to talk daemon");
81 			}
82 			nready = poll(pfd, 1, CTL_WAIT * 1000);
83 			if (nready < 0) {
84 				if (errno == EINTR)
85 					continue;
86 				p_error("Error waiting for daemon response");
87 			}
88 		} while (nready == 0);
89 		/*
90 		 * Keep reading while there are queued messages
91 		 * (this is not necessary, it just saves extra
92 		 * request/acknowledgements being sent)
93 		 */
94 		do {
95 			cc = recv(ctl_sockt, (char *)rp, sizeof (*rp), 0);
96 			if (cc < 0) {
97 				if (errno == EINTR)
98 					continue;
99 				p_error("Error on read from talk daemon");
100 			}
101 			nready = poll(pfd, 1, 0);
102 		} while (nready > 0 && (rp->vers != TALK_VERSION ||
103 		    rp->type != type));
104 	} while (rp->vers != TALK_VERSION || rp->type != type);
105 	rp->id_num = ntohl(rp->id_num);
106 	rp->addr.sa_family = ntohs(rp->addr.sa_family);
107 }
108