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  */
  37
  38 /*
  39  * The top level of the daemon, the format is heavily borrowed
  40  * from rwhod.c. Basically: find out who and where you are;
  41  * disconnect all descriptors and ttys, and then endless
  42  * loop on waiting for and processing requests
  43  */
  44 #include <sys/types.h>
  45 #include <sys/socket.h>
  46 #include <sys/param.h>
  47 #include <protocols/talkd.h>
  48 #include <err.h>
  49 #include <errno.h>
  50 #include <paths.h>
  51 #include <signal.h>
  52 #include <stdio.h>
  53 #include <stdlib.h>
  54 #include <string.h>
  55 #include <syslog.h>
  56 #include <time.h>
  57 #include <unistd.h>
  58
  59 #include "extern.h"
  60
  61 CTL_MSG         request;
  62 CTL_RESPONSE    response;
  63
  64 int     sockt;
  65 int     debug = 0;
  66 long    lastmsgtime;
  67
  68 char    hostname[MAXHOSTNAMELEN];
  69
  70 #define TIMEOUT 30
  71 #define MAXIDLE 120
  72
  73 int
  74 main(int argc, char *argv[])
  75 {
  76         CTL_MSG *mp = &request;
  77         int cc;
  78
  79 #ifdef NOTDEF
  80         /*
  81          * removed so ntalkd can run in tty sandbox
  82          */
  83         if (getuid())
  84                 errx(1, "getuid: not super-user");
  85 #endif
  86         openlog("talkd", LOG_PID, LOG_DAEMON);
  87         if (gethostname(hostname, sizeof(hostname) - 1) < 0) {
  88                 syslog(LOG_ERR, "gethostname: %m");
  89                 _exit(1);
  90         }
  91         hostname[sizeof(hostname) - 1] = '\0';
  92         if (chdir(_PATH_DEV) < 0) {
  93                 syslog(LOG_ERR, "chdir: %s: %m", _PATH_DEV);
  94                 _exit(1);
  95         }
  96         if (argc > 1 && strcmp(argv[1], "-d") == 0)
  97                 debug = 1;
  98         signal(SIGALRM, timeout);
  99         alarm(TIMEOUT);
 100         for (;;) {
 101                 cc = recv(0, (char *)mp, sizeof (*mp), 0);
 102                 if (cc != sizeof (*mp)) {
 103                         if (cc < 0 && errno != EINTR)
 104                                 syslog(LOG_WARNING, "recv: %m");
 105                         continue;
 106                 }
 107                 lastmsgtime = time(0);
 108                 process_request(mp, &response);
 109                 /* can block here, is this what I want? */
 110                 mp->ctl_addr.sa_family = htons(mp->ctl_addr.sa_family);
 111                 cc = sendto(sockt, (char *)&response,
 112                     sizeof (response), 0, (struct sockaddr *)&mp->ctl_addr,
 113                     sizeof (mp->ctl_addr));
 114                 if (cc != sizeof (response))
 115                         syslog(LOG_WARNING, "sendto: %m");
 116         }
 117 }
 118
 119 void
 120 timeout(int sig __unused)
 121 {
 122         int save_errno = errno;
 123
 124         if (time(0) - lastmsgtime >= MAXIDLE)
 125                 _exit(0);
 126         alarm(TIMEOUT);
 127         errno = save_errno;
 128 }