usr.bin/talk/get_names.c

   1 /*      $NetBSD: get_names.c,v 1.13 2007/01/08 17:10:59 christos Exp $  */
   2
   3 /*
   4  * Copyright (c) 1983, 1993
   5  *      The Regents of the University of California.  All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  * 3. Neither the name of the University nor the names of its contributors
  16  *    may be used to endorse or promote products derived from this software
  17  *    without specific prior written permission.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  29  * SUCH DAMAGE.
  30  */
  31
  32 #include <sys/cdefs.h>
  33 #ifndef lint
  34 #if 0
  35 static char sccsid[] = "@(#)get_names.c 8.1 (Berkeley) 6/6/93";
  36 #endif
  37 __RCSID("$NetBSD: get_names.c,v 1.13 2007/01/08 17:10:59 christos Exp $");
  38 #endif /* not lint */
  39
  40 #include "talk.h"
  41 #include <err.h>
  42 #include <sys/param.h>
  43 #include <pwd.h>
  44 #include <stdlib.h>
  45 #include <unistd.h>
  46 #include <util.h>
  47
  48 extern  CTL_MSG msg;
  49
  50 /*
  51  * Determine the local and remote user, tty, and machines
  52  */
  53 void
  54 get_names(argc, argv)
  55         int argc;
  56         char *argv[];
  57 {
  58         char hostname[MAXHOSTNAMELEN + 1];
  59         const char *his_name, *my_name;
  60         const char *my_machine_name, *his_machine_name;
  61         const char *his_tty;
  62         char *cp;
  63         char *names;
  64
  65         if (argc < 2 ) {
  66                 printf("usage: talk user [ttyname]\n");
  67                 exit(1);
  68         }
  69         if (!isatty(0)) {
  70                 printf("Standard input must be a tty, not a pipe or a file\n");
  71                 exit(1);
  72         }
  73         if ((my_name = getlogin()) == NULL) {
  74                 struct passwd *pw;
  75
  76                 if ((pw = getpwuid(getuid())) == NULL) {
  77                         printf("You don't exist. Go away.\n");
  78                         exit(1);
  79                 }
  80                 my_name = pw->pw_name;
  81         }
  82         if ((cp = getenv("TALKHOST")) != NULL)
  83                 (void)estrlcpy(hostname, cp, sizeof(hostname));
  84         else {
  85                 if (gethostname(hostname, sizeof(hostname)) == -1)
  86                         err(EXIT_FAILURE, "gethostname");
  87                 hostname[sizeof(hostname) - 1] = '\0';
  88         }
  89         my_machine_name = hostname;
  90         /* check for, and strip out, the machine name of the target */
  91         names = strdup(argv[1]);
  92         for (cp = names; *cp && !strchr("@:!.", *cp); cp++)
  93                 ;
  94         if (*cp == '\0') {
  95                 /* this is a local to local talk */
  96                 his_name = names;
  97                 his_machine_name = my_machine_name;
  98         } else {
  99                 if (*cp++ == '@') {
 100                         /* user@host */
 101                         his_name = names;
 102                         his_machine_name = cp;
 103                 } else {
 104                         /* host.user or host!user or host:user */
 105                         his_name = cp;
 106                         his_machine_name = names;
 107                 }
 108                 *--cp = '\0';
 109         }
 110         if (argc > 2)
 111                 his_tty = argv[2];      /* tty name is arg 2 */
 112         else
 113                 his_tty = "";
 114         get_addrs(my_machine_name, his_machine_name);
 115         /*
 116          * Initialize the message template.
 117          */
 118         msg.vers = TALK_VERSION;
 119         msg.addr.sa_family = htons(AF_INET);
 120         msg.ctl_addr.sa_family = htons(AF_INET);
 121         msg.id_num = htonl(0);
 122         strncpy(msg.l_name, my_name, NAME_SIZE);
 123         msg.l_name[NAME_SIZE - 1] = '\0';
 124         strncpy(msg.r_name, his_name, NAME_SIZE);
 125         msg.r_name[NAME_SIZE - 1] = '\0';
 126         strncpy(msg.r_tty, his_tty, TTY_SIZE);
 127         msg.r_tty[TTY_SIZE - 1] = '\0';
 128         free(names);
 129 }