1/*	$FreeBSD$	*/
2/*	$KAME: advcap.c,v 1.11 2003/05/19 09:46:50 keiichi Exp $	*/
3
4/*-
5 * SPDX-License-Identifier: BSD-3-Clause
6 *
7 * Copyright (c) 1983 The Regents of the University of California.
8 * All rights reserved.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 *    notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 *    notice, this list of conditions and the following disclaimer in the
17 *    documentation and/or other materials provided with the distribution.
18 * 3. Neither the name of the University nor the names of its contributors
19 *    may be used to endorse or promote products derived from this software
20 *    without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 */
34
35/*
36 * remcap - routines for dealing with the remote host data base
37 *
38 * derived from termcap
39 */
40#include <sys/types.h>
41#include <sys/uio.h>
42#include <unistd.h>
43#include <fcntl.h>
44#include <ctype.h>
45#include <stdlib.h>
46#include <stdio.h>
47#include <syslog.h>
48#include <errno.h>
49#include <string.h>
50#include "pathnames.h"
51
52#ifndef BUFSIZ
53#define	BUFSIZ		1024
54#endif
55#define MAXHOP		32		/* max number of tc= indirections */
56
57#define	tgetent		agetent
58#define	tnchktc		anchktc
59#define	tnamatch	anamatch
60#define	tgetnum		agetnum
61#define	tgetflag	agetflag
62#define	tgetstr		agetstr
63
64#if 0
65#define V_TERMCAP	"REMOTE"
66#define V_TERM		"HOST"
67#endif
68
69/*
70 * termcap - routines for dealing with the terminal capability data base
71 *
72 * BUG:		Should use a "last" pointer in tbuf, so that searching
73 *		for capabilities alphabetically would not be a n**2/2
74 *		process when large numbers of capabilities are given.
75 * Note:	If we add a last pointer now we will screw up the
76 *		tc capability. We really should compile termcap.
77 *
78 * Essentially all the work here is scanning and decoding escapes
79 * in string capabilities.  We don't use stdio because the editor
80 * doesn't, and because living w/o it is not hard.
81 */
82
83static	char *tbuf;
84static	int hopcount;	/* detect infinite loops in termcap, init 0 */
85
86extern const char *conffile;
87
88int tgetent(char *, char *);
89int getent(char *, char *, const char *);
90int tnchktc(void);
91int tnamatch(char *);
92static char *tskip(char *);
93int64_t tgetnum(char *);
94int tgetflag(char *);
95char *tgetstr(char *, char **);
96static char *tdecode(char *, char **);
97
98/*
99 * Get an entry for terminal name in buffer bp,
100 * from the termcap file.  Parse is very rudimentary;
101 * we just notice escaped newlines.
102 */
103int
104tgetent(char *bp, char *name)
105{
106	return (getent(bp, name, conffile));
107}
108
109int
110getent(char *bp, char *name, const char *cfile)
111{
112	int c;
113	int i = 0, cnt = 0;
114	char ibuf[BUFSIZ];
115	char *cp;
116	int tf;
117
118	tbuf = bp;
119	tf = 0;
120	/*
121	 * TERMCAP can have one of two things in it. It can be the
122	 * name of a file to use instead of /etc/termcap. In this
123	 * case it better start with a "/". Or it can be an entry to
124	 * use so we don't have to read the file. In this case it
125	 * has to already have the newlines crunched out.
126	 */
127	if (cfile && *cfile)
128		tf = open(cfile, O_RDONLY);
129
130	if (tf < 0) {
131		syslog(LOG_INFO,
132		       "<%s> open: %s", __func__, strerror(errno));
133		return (-2);
134	}
135	for (;;) {
136		cp = bp;
137		for (;;) {
138			if (i == cnt) {
139				cnt = read(tf, ibuf, BUFSIZ);
140				if (cnt <= 0) {
141					close(tf);
142					return (0);
143				}
144				i = 0;
145			}
146			c = ibuf[i++];
147			if (c == '\n') {
148				if (cp > bp && cp[-1] == '\\') {
149					cp--;
150					continue;
151				}
152				break;
153			}
154			if (cp >= bp + BUFSIZ - 1) {
155				write(STDERR_FILENO, "Remcap entry too long\n",
156				    22);
157				break;
158			} else
159				*cp++ = c;
160		}
161		*cp = 0;
162
163		/*
164		 * The real work for the match.
165		 */
166		if (tnamatch(name)) {
167			close(tf);
168			return (tnchktc());
169		}
170	}
171}
172
173/*
174 * tnchktc: check the last entry, see if it's tc=xxx. If so,
175 * recursively find xxx and append that entry (minus the names)
176 * to take the place of the tc=xxx entry. This allows termcap
177 * entries to say "like an HP2621 but doesn't turn on the labels".
178 * Note that this works because of the left to right scan.
179 */
180int
181tnchktc(void)
182{
183	char *p, *q;
184	char tcname[16];	/* name of similar terminal */
185	char tcbuf[BUFSIZ];
186	char *holdtbuf = tbuf;
187	int l;
188
189	p = tbuf + strlen(tbuf) - 2;	/* before the last colon */
190	while (*--p != ':')
191		if (p < tbuf) {
192			write(STDERR_FILENO, "Bad remcap entry\n", 18);
193			return (0);
194		}
195	p++;
196	/* p now points to beginning of last field */
197	if (p[0] != 't' || p[1] != 'c')
198		return (1);
199	strlcpy(tcname, p + 3, sizeof tcname);
200	q = tcname;
201	while (*q && *q != ':')
202		q++;
203	*q = 0;
204	if (++hopcount > MAXHOP) {
205		write(STDERR_FILENO, "Infinite tc= loop\n", 18);
206		return (0);
207	}
208	if (getent(tcbuf, tcname, conffile) != 1) {
209		return (0);
210	}
211	for (q = tcbuf; *q++ != ':'; )
212		;
213	l = p - holdtbuf + strlen(q);
214	if (l > BUFSIZ) {
215		write(STDERR_FILENO, "Remcap entry too long\n", 23);
216		q[BUFSIZ - (p-holdtbuf)] = 0;
217	}
218	strcpy(p, q);
219	tbuf = holdtbuf;
220	return (1);
221}
222
223/*
224 * Tnamatch deals with name matching.  The first field of the termcap
225 * entry is a sequence of names separated by |'s, so we compare
226 * against each such name.  The normal : terminator after the last
227 * name (before the first field) stops us.
228 */
229int
230tnamatch(char *np)
231{
232	char *Np, *Bp;
233
234	Bp = tbuf;
235	if (*Bp == '#')
236		return (0);
237	for (;;) {
238		for (Np = np; *Np && *Bp == *Np; Bp++, Np++)
239			continue;
240		if (*Np == 0 && (*Bp == '|' || *Bp == ':' || *Bp == 0))
241			return (1);
242		while (*Bp && *Bp != ':' && *Bp != '|')
243			Bp++;
244		if (*Bp == 0 || *Bp == ':')
245			return (0);
246		Bp++;
247	}
248}
249
250/*
251 * Skip to the next field.  Notice that this is very dumb, not
252 * knowing about \: escapes or any such.  If necessary, :'s can be put
253 * into the termcap file in octal.
254 */
255static char *
256tskip(char *bp)
257{
258	int dquote;
259
260	dquote = 0;
261	while (*bp) {
262		switch (*bp) {
263		case ':':
264			if (!dquote)
265				goto breakbreak;
266			else
267				bp++;
268			break;
269		case '\\':
270			bp++;
271			if (isdigit(*bp)) {
272				while (isdigit(*bp++))
273					;
274			} else
275				bp++;
276		case '"':
277			dquote = (dquote ? 1 : 0);
278			bp++;
279			break;
280		default:
281			bp++;
282			break;
283		}
284	}
285breakbreak:
286	if (*bp == ':')
287		bp++;
288	return (bp);
289}
290
291/*
292 * Return the (numeric) option id.
293 * Numeric options look like
294 *	li#80
295 * i.e. the option string is separated from the numeric value by
296 * a # character.  If the option is not found we return -1.
297 * Note that we handle octal numbers beginning with 0.
298 */
299int64_t
300tgetnum(char *id)
301{
302	int64_t i;
303	int base;
304	char *bp = tbuf;
305
306	for (;;) {
307		bp = tskip(bp);
308		if (*bp == 0)
309			return (-1);
310		if (strncmp(bp, id, strlen(id)) != 0)
311			continue;
312		bp += strlen(id);
313		if (*bp == '@')
314			return (-1);
315		if (*bp != '#')
316			continue;
317		bp++;
318		base = 10;
319		if (*bp == '0')
320			base = 8;
321		i = 0;
322		while (isdigit(*bp))
323			i *= base, i += *bp++ - '0';
324		return (i);
325	}
326}
327
328/*
329 * Handle a flag option.
330 * Flag options are given "naked", i.e. followed by a : or the end
331 * of the buffer.  Return 1 if we find the option, or 0 if it is
332 * not given.
333 */
334int
335tgetflag(char *id)
336{
337	char *bp = tbuf;
338
339	for (;;) {
340		bp = tskip(bp);
341		if (!*bp)
342			return (0);
343		if (strncmp(bp, id, strlen(id)) == 0) {
344			bp += strlen(id);
345			if (!*bp || *bp == ':')
346				return (1);
347			else if (*bp == '@')
348				return (0);
349		}
350	}
351}
352
353/*
354 * Get a string valued option.
355 * These are given as
356 *	cl=^Z
357 * Much decoding is done on the strings, and the strings are
358 * placed in area, which is a ref parameter which is updated.
359 * No checking on area overflow.
360 */
361char *
362tgetstr(char *id, char **area)
363{
364	char *bp = tbuf;
365
366	for (;;) {
367		bp = tskip(bp);
368		if (!*bp)
369			return (0);
370		if (strncmp(bp, id, strlen(id)) != 0)
371			continue;
372		bp += strlen(id);
373		if (*bp == '@')
374			return (0);
375		if (*bp != '=')
376			continue;
377		bp++;
378		return (tdecode(bp, area));
379	}
380}
381
382/*
383 * Tdecode does the grung work to decode the
384 * string capability escapes.
385 */
386static char *
387tdecode(char *str, char **area)
388{
389	char *cp;
390	int c;
391	const char *dp;
392	int i;
393	char term;
394
395	term = ':';
396	cp = *area;
397again:
398	if (*str == '"') {
399		term = '"';
400		str++;
401	}
402	while ((c = *str++) && c != term) {
403		switch (c) {
404
405		case '^':
406			c = *str++ & 037;
407			break;
408
409		case '\\':
410			dp = "E\033^^\\\\::n\nr\rt\tb\bf\f\"\"";
411			c = *str++;
412nextc:
413			if (*dp++ == c) {
414				c = *dp++;
415				break;
416			}
417			dp++;
418			if (*dp)
419				goto nextc;
420			if (isdigit(c)) {
421				c -= '0', i = 2;
422				do
423					c <<= 3, c |= *str++ - '0';
424				while (--i && isdigit(*str));
425			}
426			break;
427		}
428		*cp++ = c;
429	}
430	if (c == term && term != ':') {
431		term = ':';
432		goto again;
433	}
434	*cp++ = 0;
435	str = *area;
436	*area = cp;
437	return (str);
438}
439