usr.bin/tset/term.c

/*-
 * Copyright (c) 1991 The Regents of the University of California.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by the University of
 *      California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#ifndef lint
static char sccsid[] = "@(#)term.c      5.5 (Berkeley) 5/11/92";
#endif /* not lint */

#include <sys/types.h>
#include <errno.h>
#include <ttyent.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "extern.h"

char    tbuf[1024];                     /* Termcap entry. */

char    *askuser __P((char *));
char    *ttys __P((char *));

/*
 * Figure out what kind of terminal we're dealing with, and then read in
 * its termcap entry.
 */
char *
get_termcap_entry(userarg, tcapbufp)
        char *userarg, **tcapbufp;
{
        struct ttyent *t;
        int rval;
        char *p, *ttype, *ttypath;

        if (userarg) {
                ttype = userarg;
                goto found;
        }

        /* Try the environment. */
        if (ttype = getenv("TERM"))
                goto map;

        /* Try ttyname(3); check for dialup or other mapping. */
        if (ttypath = ttyname(STDERR_FILENO)) {
                if (p = rindex(ttypath, '/'))
                        ++p;
                else
                        p = ttypath;
                if ((t = getttynam(p))) {
                        ttype = t->ty_type;
                        goto map;
                }
        }

        /* If still undefined, use "unknown". */
        ttype = "unknown";

map:    ttype = mapped(ttype);

        /*
         * If not a path, remove TERMCAP from the environment so we get a
         * real entry from /etc/termcap.  This prevents us from being fooled
         * by out of date stuff in the environment.
         */
found:  if ((p = getenv("TERMCAP")) != NULL && *p != '/')
                unsetenv("TERMCAP");

        /*
         * ttype now contains a pointer to the type of the terminal.
         * If the first character is '?', ask the user.
         */
        if (ttype[0] == '?')
                if (ttype[1] != '\0')
                        ttype = askuser(ttype + 1);
                else
                        ttype = askuser(NULL);

        /* Find the termcap entry.  If it doesn't exist, ask the user. */
        while ((rval = tgetent(tbuf, ttype)) == 0) {
                (void)fprintf(stderr,
                    "tset: terminal type %s is unknown\n", ttype);
                ttype = askuser(NULL);
        }
        if (rval == -1)
                err("termcap: %s", strerror(errno ? errno : ENOENT));
        *tcapbufp = tbuf;
        return (ttype);
}

/* Prompt the user for a terminal type. */
char *
askuser(dflt)
        char *dflt;
{
        static char answer[256];
        char *p;

        /* We can get recalled; if so, don't continue uselessly. */
        if (feof(stdin) || ferror(stdin)) {
                (void)fprintf(stderr, "\n");
                exit(1);
        }
        for (;;) {
                if (dflt)
                        (void)fprintf(stderr, "Terminal type? [%s] ", dflt);
                else
                        (void)fprintf(stderr, "Terminal type? ");
                (void)fflush(stderr);

                if (fgets(answer, sizeof(answer), stdin) == NULL) {
                        if (dflt == NULL) {
                                (void)fprintf(stderr, "\n");
                                exit(1);
                        }
                        return (dflt);
                }

                if (p = index(answer, '\n'))
                        *p = '\0';
                if (answer[0])
                        return (answer);
                if (dflt != NULL)
                        return (dflt);
        }
}