1/*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1991, 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
34__FBSDID("$FreeBSD$");
35
36#ifndef lint
37static const char sccsid[] = "@(#)term.c	8.1 (Berkeley) 6/9/93";
38#endif
39
40#include <sys/types.h>
41#include <err.h>
42#include <errno.h>
43#include <stdio.h>
44#include <stdlib.h>
45#include <string.h>
46#include <termcap.h>
47#include <unistd.h>
48#include <ttyent.h>
49#include "extern.h"
50
51static char tbuf[1024];		/* Termcap entry. */
52
53const char *askuser(const char *);
54char	*ttys(char *);
55
56/*
57 * Figure out what kind of terminal we're dealing with, and then read in
58 * its termcap entry.
59 */
60const char *
61get_termcap_entry(char *userarg, char **tcapbufp)
62{
63	struct ttyent *t;
64	int rval;
65	char *p, *ttypath;
66	const char *ttype;
67
68	if (userarg) {
69		ttype = userarg;
70		goto found;
71	}
72
73	/* Try the environment. */
74	if ((ttype = getenv("TERM")))
75		goto map;
76
77	/* Try ttyname(3); check for dialup or other mapping. */
78	if ((ttypath = ttyname(STDERR_FILENO))) {
79		if ((p = strrchr(ttypath, '/')))
80			++p;
81		else
82			p = ttypath;
83		if ((t = getttynam(p))) {
84			ttype = t->ty_type;
85			goto map;
86		}
87	}
88
89	/* If still undefined, use "unknown". */
90	ttype = "unknown";
91
92map:	ttype = mapped(ttype);
93
94	/*
95	 * If not a path, remove TERMCAP from the environment so we get a
96	 * real entry from /etc/termcap.  This prevents us from being fooled
97	 * by out of date stuff in the environment.
98	 */
99found:	if ((p = getenv("TERMCAP")) != NULL && *p != '/')
100		unsetenv("TERMCAP");
101
102	/*
103	 * ttype now contains a pointer to the type of the terminal.
104	 * If the first character is '?', ask the user.
105	 */
106	if (ttype[0] == '?') {
107		if (ttype[1] != '\0')
108			ttype = askuser(ttype + 1);
109		else
110			ttype = askuser(NULL);
111	}
112
113	/* Find the termcap entry.  If it doesn't exist, ask the user. */
114	while ((rval = tgetent(tbuf, ttype)) == 0) {
115		warnx("terminal type %s is unknown", ttype);
116		ttype = askuser(NULL);
117	}
118	if (rval == -1)
119		errx(1, "termcap: %s", strerror(errno ? errno : ENOENT));
120	*tcapbufp = tbuf;
121	return (ttype);
122}
123
124/* Prompt the user for a terminal type. */
125const char *
126askuser(const char *dflt)
127{
128	static char answer[256];
129	char *p;
130
131	/* We can get recalled; if so, don't continue uselessly. */
132	if (feof(stdin) || ferror(stdin)) {
133		(void)fprintf(stderr, "\n");
134		exit(1);
135	}
136	for (;;) {
137		if (dflt)
138			(void)fprintf(stderr, "Terminal type? [%s] ", dflt);
139		else
140			(void)fprintf(stderr, "Terminal type? ");
141		(void)fflush(stderr);
142
143		if (fgets(answer, sizeof(answer), stdin) == NULL) {
144			if (dflt == NULL) {
145				(void)fprintf(stderr, "\n");
146				exit(1);
147			}
148			return (dflt);
149		}
150
151		if ((p = strchr(answer, '\n')))
152			*p = '\0';
153		if (answer[0])
154			return (answer);
155		if (dflt != NULL)
156			return (dflt);
157	}
158}
159