usr.bin/talk/get_names.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. Neither the name of the University nor the names of its contributors
  14  *    may be used to endorse or promote products derived from this software
  15  *    without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  *
  29  * @(#)get_names.c      8.1 (Berkeley) 6/6/93
  30  * $FreeBSD: src/usr.bin/talk/get_names.c,v 1.6.2.1 2001/07/30 10:31:29 dd Exp $
  31  */
  32
  33 #include <err.h>
  34 #include <pwd.h>
  35 #include <stdlib.h>
  36 #include <string.h>
  37 #include <sys/param.h>
  38 #include "talk.h"
  39
  40 extern  CTL_MSG msg;
  41
  42 static void
  43 usage(void)
  44 {
  45         fprintf(stderr, "usage: talk person [ttyname]\n");
  46         exit(1);
  47 }
  48
  49 /*
  50  * Determine the local and remote user, tty, and machines
  51  */
  52 void
  53 get_names(int argc, char **argv)
  54 {
  55         char hostname[MAXHOSTNAMELEN];
  56         char *his_name, *my_name;
  57         char *my_machine_name, *his_machine_name;
  58         const char *his_tty;
  59         char *cp;
  60
  61         if (argc < 2 )
  62                 usage();
  63         if (!isatty(0))
  64                 errx(1, "standard input must be a tty, not a pipe or a file");
  65         if ((my_name = getlogin()) == NULL) {
  66                 struct passwd *pw;
  67
  68                 if ((pw = getpwuid(getuid())) == NULL)
  69                         errx(1, "you don't exist. Go away");
  70                 my_name = pw->pw_name;
  71         }
  72         gethostname(hostname, sizeof (hostname));
  73         my_machine_name = hostname;
  74         /* check for, and strip out, the machine name of the target */
  75         for (cp = argv[1]; *cp && !strchr("@:!", *cp); cp++)
  76                 ;
  77         if (*cp == '\0') {
  78                 /* this is a local to local talk */
  79                 his_name = argv[1];
  80                 his_machine_name = my_machine_name;
  81         } else {
  82                 if (*cp++ == '@') {
  83                         /* user@host */
  84                         his_name = argv[1];
  85                         his_machine_name = cp;
  86                 } else {
  87                         /* host!user or host:user */
  88                         his_name = cp;
  89                         his_machine_name = argv[1];
  90                 }
  91                 *--cp = '\0';
  92         }
  93         if (argc > 2)
  94                 his_tty = argv[2];      /* tty name is arg 2 */
  95         else
  96                 his_tty = "";
  97         get_addrs(my_machine_name, his_machine_name);
  98         /*
  99          * Initialize the message template.
 100          */
 101         msg.vers = TALK_VERSION;
 102         msg.addr.sa_family = htons(AF_INET);
 103         msg.ctl_addr.sa_family = htons(AF_INET);
 104         msg.id_num = htonl(0);
 105         strncpy(msg.l_name, my_name, NAME_SIZE);
 106         msg.l_name[NAME_SIZE - 1] = '\0';
 107         strncpy(msg.r_name, his_name, NAME_SIZE);
 108         msg.r_name[NAME_SIZE - 1] = '\0';
 109         strncpy(msg.r_tty, his_tty, TTY_SIZE);
 110         msg.r_tty[TTY_SIZE - 1] = '\0';
 111 }