1/*	$KAME: advcap.c,v 1.11 2003/05/19 09:46:50 keiichi Exp $	*/
2
3/*-
4 * SPDX-License-Identifier: BSD-3-Clause
5 *
6 * Copyright (c) 1983 The Regents of the University of California.
7 * All rights reserved.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 *    notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 *    notice, this list of conditions and the following disclaimer in the
16 *    documentation and/or other materials provided with the distribution.
17 * 3. 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/*
35 * remcap - routines for dealing with the remote host data base
36 *
37 * derived from termcap
38 */
39#include <sys/types.h>
40#include <sys/uio.h>
41#include <unistd.h>
42#include <fcntl.h>
43#include <ctype.h>
44#include <stdlib.h>
45#include <stdio.h>
46#include <syslog.h>
47#include <errno.h>
48#include <string.h>
49#include "pathnames.h"
50
51#ifndef BUFSIZ
52#define	BUFSIZ		1024
53#endif
54#define MAXHOP		32		/* max number of tc= indirections */
55
56#define	tgetent		agetent
57#define	tnchktc		anchktc
58#define	tnamatch	anamatch
59#define	tgetnum		agetnum
60#define	tgetflag	agetflag
61#define	tgetstr		agetstr
62
63#if 0
64#define V_TERMCAP	"REMOTE"
65#define V_TERM		"HOST"
66#endif
67
68/*
69 * termcap - routines for dealing with the terminal capability data base
70 *
71 * BUG:		Should use a "last" pointer in tbuf, so that searching
72 *		for capabilities alphabetically would not be a n**2/2
73 *		process when large numbers of capabilities are given.
74 * Note:	If we add a last pointer now we will screw up the
75 *		tc capability. We really should compile termcap.
76 *
77 * Essentially all the work here is scanning and decoding escapes
78 * in string capabilities.  We don't use stdio because the editor
79 * doesn't, and because living w/o it is not hard.
80 */
81
82static	char *tbuf;
83static	int hopcount;	/* detect infinite loops in termcap, init 0 */
84
85extern const char *conffile;
86
87int tgetent(char *, char *);
88int getent(char *, char *, const char *);
89int tnchktc(void);
90int tnamatch(char *);
91static char *tskip(char *);
92int64_t tgetnum(char *);
93int tgetflag(char *);
94char *tgetstr(char *, char **);
95static char *tdecode(char *, char **);
96
97/*
98 * Get an entry for terminal name in buffer bp,
99 * from the termcap file.  Parse is very rudimentary;
100 * we just notice escaped newlines.
101 */
102int
103tgetent(char *bp, char *name)
104{
105	return (getent(bp, name, conffile));
106}
107
108int
109getent(char *bp, char *name, const char *cfile)
110{
111	int c;
112	int i = 0, cnt = 0;
113	char ibuf[BUFSIZ];
114	char *cp;
115	int tf;
116
117	tbuf = bp;
118	tf = 0;
119	/*
120	 * TERMCAP can have one of two things in it. It can be the
121	 * name of a file to use instead of /etc/termcap. In this
122	 * case it better start with a "/". Or it can be an entry to
123	 * use so we don't have to read the file. In this case it
124	 * has to already have the newlines crunched out.
125	 */
126	if (cfile && *cfile)
127		tf = open(cfile, O_RDONLY);
128
129	if (tf < 0) {
130		syslog(LOG_INFO,
131		       "<%s> open: %s", __func__, strerror(errno));
132		return (-2);
133	}
134	for (;;) {
135		cp = bp;
136		for (;;) {
137			if (i == cnt) {
138				cnt = read(tf, ibuf, BUFSIZ);
139				if (cnt <= 0) {
140					close(tf);
141					return (0);
142				}
143				i = 0;
144			}
145			c = ibuf[i++];
146			if (c == '\n') {
147				if (cp > bp && cp[-1] == '\\') {
148					cp--;
149					continue;
150				}
151				break;
152			}
153			if (cp >= bp + BUFSIZ - 1) {
154				write(STDERR_FILENO, "Remcap entry too long\n",
155				    22);
156				break;
157			} else
158				*cp++ = c;
159		}
160		*cp = 0;
161
162		/*
163		 * The real work for the match.
164		 */
165		if (tnamatch(name)) {
166			close(tf);
167			return (tnchktc());
168		}
169	}
170}
171
172/*
173 * tnchktc: check the last entry, see if it's tc=xxx. If so,
174 * recursively find xxx and append that entry (minus the names)
175 * to take the place of the tc=xxx entry. This allows termcap
176 * entries to say "like an HP2621 but doesn't turn on the labels".
177 * Note that this works because of the left to right scan.
178 */
179int
180tnchktc(void)
181{
182	char *p, *q;
183	char tcname[16];	/* name of similar terminal */
184	char tcbuf[BUFSIZ];
185	char *holdtbuf = tbuf;
186	int l;
187
188	p = tbuf + strlen(tbuf) - 2;	/* before the last colon */
189	while (*--p != ':')
190		if (p < tbuf) {
191			write(STDERR_FILENO, "Bad remcap entry\n", 18);
192			return (0);
193		}
194	p++;
195	/* p now points to beginning of last field */
196	if (p[0] != 't' || p[1] != 'c')
197		return (1);
198	strlcpy(tcname, p + 3, sizeof tcname);
199	q = tcname;
200	while (*q && *q != ':')
201		q++;
202	*q = 0;
203	if (++hopcount > MAXHOP) {
204		write(STDERR_FILENO, "Infinite tc= loop\n", 18);
205		return (0);
206	}
207	if (getent(tcbuf, tcname, conffile) != 1) {
208		return (0);
209	}
210	for (q = tcbuf; *q++ != ':'; )
211		;
212	l = p - holdtbuf + strlen(q);
213	if (l > BUFSIZ) {
214		write(STDERR_FILENO, "Remcap entry too long\n", 23);
215		q[BUFSIZ - (p-holdtbuf)] = 0;
216	}
217	strcpy(p, q);
218	tbuf = holdtbuf;
219	return (1);
220}
221
222/*
223 * Tnamatch deals with name matching.  The first field of the termcap
224 * entry is a sequence of names separated by |'s, so we compare
225 * against each such name.  The normal : terminator after the last
226 * name (before the first field) stops us.
227 */
228int
229tnamatch(char *np)
230{
231	char *Np, *Bp;
232
233	Bp = tbuf;
234	if (*Bp == '#')
235		return (0);
236	for (;;) {
237		for (Np = np; *Np && *Bp == *Np; Bp++, Np++)
238			continue;
239		if (*Np == 0 && (*Bp == '|' || *Bp == ':' || *Bp == 0))
240			return (1);
241		while (*Bp && *Bp != ':' && *Bp != '|')
242			Bp++;
243		if (*Bp == 0 || *Bp == ':')
244			return (0);
245		Bp++;
246	}
247}
248
249/*
250 * Skip to the next field.  Notice that this is very dumb, not
251 * knowing about \: escapes or any such.  If necessary, :'s can be put
252 * into the termcap file in octal.
253 */
254static char *
255tskip(char *bp)
256{
257	int dquote;
258
259	dquote = 0;
260	while (*bp) {
261		switch (*bp) {
262		case ':':
263			if (!dquote)
264				goto breakbreak;
265			else
266				bp++;
267			break;
268		case '\\':
269			bp++;
270			if (isdigit(*bp)) {
271				while (isdigit(*bp++))
272					;
273			} else
274				bp++;
275		case '"':
276			dquote = (dquote ? 1 : 0);
277			bp++;
278			break;
279		default:
280			bp++;
281			break;
282		}
283	}
284breakbreak:
285	if (*bp == ':')
286		bp++;
287	return (bp);
288}
289
290/*
291 * Return the (numeric) option id.
292 * Numeric options look like
293 *	li#80
294 * i.e. the option string is separated from the numeric value by
295 * a # character.  If the option is not found we return -1.
296 * Note that we handle octal numbers beginning with 0.
297 */
298int64_t
299tgetnum(char *id)
300{
301	int64_t i;
302	int base;
303	char *bp = tbuf;
304
305	for (;;) {
306		bp = tskip(bp);
307		if (*bp == 0)
308			return (-1);
309		if (strncmp(bp, id, strlen(id)) != 0)
310			continue;
311		bp += strlen(id);
312		if (*bp == '@')
313			return (-1);
314		if (*bp != '#')
315			continue;
316		bp++;
317		base = 10;
318		if (*bp == '0')
319			base = 8;
320		i = 0;
321		while (isdigit(*bp))
322			i *= base, i += *bp++ - '0';
323		return (i);
324	}
325}
326
327/*
328 * Handle a flag option.
329 * Flag options are given "naked", i.e. followed by a : or the end
330 * of the buffer.  Return 1 if we find the option, or 0 if it is
331 * not given.
332 */
333int
334tgetflag(char *id)
335{
336	char *bp = tbuf;
337
338	for (;;) {
339		bp = tskip(bp);
340		if (!*bp)
341			return (0);
342		if (strncmp(bp, id, strlen(id)) == 0) {
343			bp += strlen(id);
344			if (!*bp || *bp == ':')
345				return (1);
346			else if (*bp == '@')
347				return (0);
348		}
349	}
350}
351
352/*
353 * Get a string valued option.
354 * These are given as
355 *	cl=^Z
356 * Much decoding is done on the strings, and the strings are
357 * placed in area, which is a ref parameter which is updated.
358 * No checking on area overflow.
359 */
360char *
361tgetstr(char *id, char **area)
362{
363	char *bp = tbuf;
364
365	for (;;) {
366		bp = tskip(bp);
367		if (!*bp)
368			return (0);
369		if (strncmp(bp, id, strlen(id)) != 0)
370			continue;
371		bp += strlen(id);
372		if (*bp == '@')
373			return (0);
374		if (*bp != '=')
375			continue;
376		bp++;
377		return (tdecode(bp, area));
378	}
379}
380
381/*
382 * Tdecode does the grung work to decode the
383 * string capability escapes.
384 */
385static char *
386tdecode(char *str, char **area)
387{
388	char *cp;
389	int c;
390	const char *dp;
391	int i;
392	char term;
393
394	term = ':';
395	cp = *area;
396again:
397	if (*str == '"') {
398		term = '"';
399		str++;
400	}
401	while ((c = *str++) && c != term) {
402		switch (c) {
403
404		case '^':
405			c = *str++ & 037;
406			break;
407
408		case '\\':
409			dp = "E\033^^\\\\::n\nr\rt\tb\bf\f\"\"";
410			c = *str++;
411nextc:
412			if (*dp++ == c) {
413				c = *dp++;
414				break;
415			}
416			dp++;
417			if (*dp)
418				goto nextc;
419			if (isdigit(c)) {
420				c -= '0', i = 2;
421				do
422					c <<= 3, c |= *str++ - '0';
423				while (--i && isdigit(*str));
424			}
425			break;
426		}
427		*cp++ = c;
428	}
429	if (c == term && term != ':') {
430		term = ':';
431		goto again;
432	}
433	*cp++ = 0;
434	str = *area;
435	*area = cp;
436	return (str);
437}
438