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talkd.c revision 1.4 
      1 /*
      2  * Copyright (c) 1983 Regents of the University of California.
      3  * 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 #ifndef lint
     35 char copyright[] =
     36 "@(#) Copyright (c) 1983 Regents of the University of California.\n\
     37  All rights reserved.\n";
     38 #endif /* not lint */
     39 
     40 #ifndef lint
     41 /*static char sccsid[] = "from: @(#)talkd.c	5.8 (Berkeley) 2/26/91";*/
     42 static char rcsid[] = "$Id: talkd.c,v 1.4 1997/01/29 10:30:14 explorer Exp $";
     43 #endif /* not lint */
     44 
     45 /*
     46  * The top level of the daemon, the format is heavily borrowed
     47  * from rwhod.c. Basically: find out who and where you are;
     48  * disconnect all descriptors and ttys, and then endless
     49  * loop on waiting for and processing requests
     50  */
     51 #include <sys/types.h>
     52 #include <sys/socket.h>
     53 #include <sys/param.h>
     54 
     55 #include <protocols/talkd.h>
     56 #include <signal.h>
     57 #include <syslog.h>
     58 #include <time.h>
     59 #include <errno.h>
     60 #include <unistd.h>
     61 #include <stdio.h>
     62 #include <stdlib.h>
     63 #include <string.h>
     64 #include <paths.h>
     65 
     66 CTL_MSG		request;
     67 CTL_RESPONSE	response;
     68 
     69 int	sockt;
     70 int	debug = 0;
     71 void	timeout();
     72 long	lastmsgtime;
     73 
     74 char	hostname[MAXHOSTNAMELEN + 1];
     75 
     76 #define TIMEOUT 30
     77 #define MAXIDLE 120
     78 
     79 main(argc, argv)
     80 	int argc;
     81 	char *argv[];
     82 {
     83 	register CTL_MSG *mp = &request;
     84 	int cc;
     85 
     86 	if (getuid()) {
     87 		fprintf(stderr, "%s: getuid: not super-user", argv[0]);
     88 		exit(1);
     89 	}
     90 	openlog("talkd", LOG_PID, LOG_DAEMON);
     91 	if (gethostname(hostname, sizeof (hostname) - 1) < 0) {
     92 		syslog(LOG_ERR, "gethostname: %m");
     93 		_exit(1);
     94 	}
     95 	hostname[MAXHOSTNAMELEN] = 0;  /* ensure null termination */
     96 	if (chdir(_PATH_DEV) < 0) {
     97 		syslog(LOG_ERR, "chdir: %s: %m", _PATH_DEV);
     98 		_exit(1);
     99 	}
    100 	if (argc > 1 && strcmp(argv[1], "-d") == 0)
    101 		debug = 1;
    102 	signal(SIGALRM, timeout);
    103 	alarm(TIMEOUT);
    104 	for (;;) {
    105 		extern int errno;
    106 
    107 		cc = recv(0, (char *)mp, sizeof (*mp), 0);
    108 		if (cc != sizeof (*mp)) {
    109 			if (cc < 0 && errno != EINTR)
    110 				syslog(LOG_WARNING, "recv: %m");
    111 			continue;
    112 		}
    113 		lastmsgtime = time(0);
    114 		process_request(mp, &response);
    115 		/* can block here, is this what I want? */
    116 		cc = sendto(sockt, (char *)&response,
    117 		    sizeof (response), 0, (struct sockaddr *)&mp->ctl_addr,
    118 		    sizeof (mp->ctl_addr));
    119 		if (cc != sizeof (response))
    120 			syslog(LOG_WARNING, "sendto: %m");
    121 	}
    122 }
    123 
    124 void
    125 timeout()
    126 {
    127 
    128 	if (time(0) - lastmsgtime >= MAXIDLE)
    129 		_exit(0);
    130 	alarm(TIMEOUT);
    131 }
    132