xref: /freebsd/usr.bin/talk/ctl_transact.c (revision af6a5351a1fdb1130f18be6c782c4d48916eb971)
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. Neither the name of the University nor the names of its contributors
14  *    may be used to endorse or promote products derived from this software
15  *    without specific prior written permission.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  */
29 
30 #include <sys/cdefs.h>
31 
32 __FBSDID("$FreeBSD$");
33 
34 #ifndef lint
35 static const char sccsid[] = "@(#)ctl_transact.c	8.1 (Berkeley) 6/6/93";
36 #endif
37 
38 #include <arpa/inet.h>
39 
40 #include <errno.h>
41 #include <poll.h>
42 
43 #include "talk.h"
44 #include "talk_ctl.h"
45 
46 #define CTL_WAIT 2	/* time to wait for a response, in seconds */
47 
48 /*
49  * SOCKDGRAM is unreliable, so we must repeat messages if we have
50  * not received an acknowledgement within a reasonable amount
51  * of time
52  */
53 void
54 ctl_transact(struct in_addr target, CTL_MSG lmsg, int type, CTL_RESPONSE *rp)
55 {
56 	struct pollfd pfd[1];
57 	int nready = 0, cc;
58 
59 	lmsg.type = type;
60 	daemon_addr.sin_addr = target;
61 	daemon_addr.sin_port = daemon_port;
62 	pfd[0].fd = ctl_sockt;
63 	pfd[0].events = POLLIN;
64 
65 	/*
66 	 * Keep sending the message until a response of
67 	 * the proper type is obtained.
68 	 */
69 	do {
70 		/* resend message until a response is obtained */
71 		do {
72 			cc = sendto(ctl_sockt, (char *)&lmsg, sizeof (lmsg), 0,
73 			    (struct sockaddr *)&daemon_addr,
74 			    sizeof (daemon_addr));
75 			if (cc != sizeof (lmsg)) {
76 				if (errno == EINTR)
77 					continue;
78 				p_error("Error on write to talk daemon");
79 			}
80 			nready = poll(pfd, 1, CTL_WAIT * 1000);
81 			if (nready < 0) {
82 				if (errno == EINTR)
83 					continue;
84 				p_error("Error waiting for daemon response");
85 			}
86 		} while (nready == 0);
87 		/*
88 		 * Keep reading while there are queued messages
89 		 * (this is not necessary, it just saves extra
90 		 * request/acknowledgements being sent)
91 		 */
92 		do {
93 			cc = recv(ctl_sockt, (char *)rp, sizeof (*rp), 0);
94 			if (cc < 0) {
95 				if (errno == EINTR)
96 					continue;
97 				p_error("Error on read from talk daemon");
98 			}
99 			nready = poll(pfd, 1, 0);
100 		} while (nready > 0 && (rp->vers != TALK_VERSION ||
101 		    rp->type != type));
102 	} while (rp->vers != TALK_VERSION || rp->type != type);
103 	rp->id_num = ntohl(rp->id_num);
104 	rp->addr.sa_family = ntohs(rp->addr.sa_family);
105 }
106