Ultrix-3.1/src/ucb/talk/get_names.c

/**********************************************************************
 *   Copyright (c) Digital Equipment Corporation 1984, 1985, 1986.    *
 *   All Rights Reserved. 					      *
 *   Reference "/usr/src/COPYRIGHT" for applicable restrictions.      *
 **********************************************************************/

static char *Sccsid = "@(#)get_names.c	3.0	(ULTRIX-11)	4/22/86";

#include "talk.h"
#include "ctl.h"

char *getlogin(), *ttyname(), *rindex();

extern CTL_MSG msg;

/*
 * Determine the local and remote user, tty, and machines
 */

struct hostent *gethostbyname();

get_names(argc, argv)
int argc;
char *argv[];
{
    char hostname[HOST_NAME_LENGTH];
    char *his_name;
    char *my_name;
    char *my_machine_name;
    char *his_machine_name;
    char *my_tty;
    char *his_tty;
    char *ptr;
    int name_length;

    if (argc < 2 ) {
	printf("Usage:  talk user [ttyname]\n");
	exit(-1);
    }
    if ( !isatty(0) ) {
	printf("Standard input must be a tty, not a pipe or a file\n");
	exit(-1);
    }

    my_name = getlogin();
    if (my_name == NULL) {
	printf("You don't exist. Go away.\n");
	exit(-1);
    }

    /*
     * See if we have networking in the kernel.  The listen()
     * call should always fail, and by looking at errno we'll
     * know whether or not we have networking.  EINVAL indicates
     * no networking, EBADF means we do.
     */

    if (listen(-1,0) < 0) {
#include <errno.h>
	if (errno != EINVAL)
	    ;		/* HaveNetwork = TRUE; */
	else {
	    printf("Sorry, talk requires kernel network support.\n");
	    exit(-1);
	}
    }

    name_length = HOST_NAME_LENGTH;
    gethostname(hostname, &name_length);
    my_machine_name = hostname;

    my_tty = rindex(ttyname(0), '/') + 1;

	/* check for, and strip out, the machine name 
	    of the target */

    for (ptr = argv[1]; *ptr != '\0' &&
			 *ptr != '@' &&
			 *ptr != ':' &&
			 *ptr != '!' &&
			 *ptr != '.'     ; ptr++) {
    }

    if (*ptr == '\0') {

	    /* this is a local to local talk */

	his_name = argv[1];
	his_machine_name = my_machine_name;

    } else {

	if (*ptr == '@') {
		/* user@host */
	    his_name = argv[1];
	    his_machine_name = ptr + 1;
	} else {
		/* host.user or host!user or host:user */
	    his_name = ptr + 1;
	    his_machine_name = argv[1];
	}
	*ptr = '\0';
    }


    if (argc > 2) {
	his_tty = argv[2];	/* tty name is arg 2 */
    } else {
	his_tty = (char *) 0;
    }

    get_addrs(my_machine_name, his_machine_name);

	/* Load these useful values into the standard message header */

    msg.id_num = 0;

    strncpy(msg.l_name, my_name, NAME_SIZE);
    msg.l_name[NAME_SIZE - 1] = '\0';

    strncpy(msg.r_name, his_name, NAME_SIZE);
    msg.r_name[NAME_SIZE - 1] = '\0';

    if (his_tty)
	    strncpy(msg.r_tty, his_tty, TTY_SIZE);
    else
	    msg.r_tty[0] = '\0';
    msg.r_tty[TTY_SIZE - 1] = '\0';
}