term.c revision 1591 
1/*-
2 * Copyright (c) 1991, 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
34#ifndef lint
35static char sccsid[] = "@(#)term.c	8.1 (Berkeley) 6/9/93";
36#endif /* not lint */
37
38#include <sys/types.h>
39#include <errno.h>
40#include <ttyent.h>
41#include <unistd.h>
42#include <stdio.h>
43#include <stdlib.h>
44#include <string.h>
45#include "extern.h"
46
47char    tbuf[1024];      		/* Termcap entry. */
48
49char	*askuser __P((char *));
50char	*ttys __P((char *));
51
52/*
53 * Figure out what kind of terminal we're dealing with, and then read in
54 * its termcap entry.
55 */
56char *
57get_termcap_entry(userarg, tcapbufp)
58	char *userarg, **tcapbufp;
59{
60	struct ttyent *t;
61	int rval;
62	char *p, *ttype, *ttypath;
63
64	if (userarg) {
65		ttype = userarg;
66		goto found;
67	}
68
69	/* Try the environment. */
70	if (ttype = getenv("TERM"))
71		goto map;
72
73	/* Try ttyname(3); check for dialup or other mapping. */
74	if (ttypath = ttyname(STDERR_FILENO)) {
75		if (p = rindex(ttypath, '/'))
76			++p;
77		else
78			p = ttypath;
79		if ((t = getttynam(p))) {
80			ttype = t->ty_type;
81			goto map;
82		}
83	}
84
85	/* If still undefined, use "unknown". */
86	ttype = "unknown";
87
88map:	ttype = mapped(ttype);
89
90	/*
91	 * If not a path, remove TERMCAP from the environment so we get a
92	 * real entry from /etc/termcap.  This prevents us from being fooled
93	 * by out of date stuff in the environment.
94	 */
95found:	if ((p = getenv("TERMCAP")) != NULL && *p != '/')
96		unsetenv("TERMCAP");
97
98	/*
99	 * ttype now contains a pointer to the type of the terminal.
100	 * If the first character is '?', ask the user.
101	 */
102	if (ttype[0] == '?')
103		if (ttype[1] != '\0')
104			ttype = askuser(ttype + 1);
105		else
106			ttype = askuser(NULL);
107
108	/* Find the termcap entry.  If it doesn't exist, ask the user. */
109	while ((rval = tgetent(tbuf, ttype)) == 0) {
110		(void)fprintf(stderr,
111		    "tset: terminal type %s is unknown\n", ttype);
112		ttype = askuser(NULL);
113	}
114	if (rval == -1)
115		err("termcap: %s", strerror(errno ? errno : ENOENT));
116	*tcapbufp = tbuf;
117	return (ttype);
118}
119
120/* Prompt the user for a terminal type. */
121char *
122askuser(dflt)
123	char *dflt;
124{
125	static char answer[256];
126	char *p;
127
128	/* We can get recalled; if so, don't continue uselessly. */
129	if (feof(stdin) || ferror(stdin)) {
130		(void)fprintf(stderr, "\n");
131		exit(1);
132	}
133	for (;;) {
134		if (dflt)
135			(void)fprintf(stderr, "Terminal type? [%s] ", dflt);
136		else
137			(void)fprintf(stderr, "Terminal type? ");
138		(void)fflush(stderr);
139
140		if (fgets(answer, sizeof(answer), stdin) == NULL) {
141			if (dflt == NULL) {
142				(void)fprintf(stderr, "\n");
143				exit(1);
144			}
145			return (dflt);
146		}
147
148		if (p = index(answer, '\n'))
149			*p = '\0';
150		if (answer[0])
151			return (answer);
152		if (dflt != NULL)
153			return (dflt);
154	}
155}
156