xref: /freebsd/usr.bin/talk/ctl_transact.c (revision 830940567b49bb0c08dfaed40418999e76616909)
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("$FreeBSD$");
37 
38 #ifndef lint
39 static 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  */
57 void
58 ctl_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