libexec/talkd/talkd.c

   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  * @(#) Copyright (c) 1983, 1993 The Regents of the University of California.  All rights reserved.
  34  * @(#)talkd.c  8.1 (Berkeley) 6/4/93
  35  * $FreeBSD: src/libexec/talkd/talkd.c,v 1.11.2.1 2001/10/18 12:30:42 des Exp $
  36  * $DragonFly: src/libexec/talkd/talkd.c,v 1.3 2003/11/14 03:54:31 dillon Exp $
  37  */
  38
  39 /*
  40  * The top level of the daemon, the format is heavily borrowed
  41  * from rwhod.c. Basically: find out who and where you are;
  42  * disconnect all descriptors and ttys, and then endless
  43  * loop on waiting for and processing requests
  44  */
  45 #include <sys/types.h>
  46 #include <sys/socket.h>
  47 #include <sys/param.h>
  48 #include <protocols/talkd.h>
  49 #include <err.h>
  50 #include <errno.h>
  51 #include <paths.h>
  52 #include <signal.h>
  53 #include <stdio.h>
  54 #include <stdlib.h>
  55 #include <string.h>
  56 #include <syslog.h>
  57 #include <time.h>
  58 #include <unistd.h>
  59
  60 CTL_MSG         request;
  61 CTL_RESPONSE    response;
  62
  63 int     sockt;
  64 int     debug = 0;
  65 long    lastmsgtime;
  66
  67 char    hostname[MAXHOSTNAMELEN];
  68
  69 #define TIMEOUT 30
  70 #define MAXIDLE 120
  71
  72 void process_request (CTL_MSG *, CTL_RESPONSE *);
  73 void timeout();
  74
  75 int
  76 main(argc, argv)
  77         int argc;
  78         char *argv[];
  79 {
  80         register CTL_MSG *mp = &request;
  81         int cc;
  82
  83 #ifdef NOTDEF
  84         /*
  85          * removed so ntalkd can run in tty sandbox
  86          */
  87         if (getuid())
  88                 errx(1, "getuid: not super-user");
  89 #endif
  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[sizeof(hostname) - 1] = '\0';
  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                 cc = recv(0, (char *)mp, sizeof (*mp), 0);
 106                 if (cc != sizeof (*mp)) {
 107                         if (cc < 0 && errno != EINTR)
 108                                 syslog(LOG_WARNING, "recv: %m");
 109                         continue;
 110                 }
 111                 lastmsgtime = time(0);
 112                 process_request(mp, &response);
 113                 /* can block here, is this what I want? */
 114                 mp->ctl_addr.sa_family = htons(mp->ctl_addr.sa_family);
 115                 cc = sendto(sockt, (char *)&response,
 116                     sizeof (response), 0, (struct sockaddr *)&mp->ctl_addr,
 117                     sizeof (mp->ctl_addr));
 118                 if (cc != sizeof (response))
 119                         syslog(LOG_WARNING, "sendto: %m");
 120         }
 121 }
 122
 123 void
 124 timeout()
 125 {
 126         int save_errno = errno;
 127
 128         if (time(0) - lastmsgtime >= MAXIDLE)
 129                 _exit(0);
 130         alarm(TIMEOUT);
 131         errno = save_errno;
 132 }