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      1 /*	$NetBSD: advcap.c,v 1.19 2021/03/23 18:16:53 christos Exp $	*/
      2 /*	$KAME: advcap.c,v 1.11 2003/05/19 09:46:50 keiichi Exp $	*/
      3 
      4 /*
      5  * Copyright (c) 1983 The Regents of the University of California.
      6  * All rights reserved.
      7  *
      8  * Redistribution and use in source and binary forms, with or without
      9  * modification, are permitted provided that the following conditions
     10  * are met:
     11  * 1. Redistributions of source code must retain the above copyright
     12  *    notice, this list of conditions and the following disclaimer.
     13  * 2. Redistributions in binary form must reproduce the above copyright
     14  *    notice, this list of conditions and the following disclaimer in the
     15  *    documentation and/or other materials provided with the distribution.
     16  * 3. Neither the name of the University nor the names of its contributors
     17  *    may be used to endorse or promote products derived from this software
     18  *    without specific prior written permission.
     19  *
     20  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     30  * SUCH DAMAGE.
     31  */
     32 
     33 /*
     34  * remcap - routines for dealing with the remote host data base
     35  *
     36  * derived from termcap
     37  */
     38 #include <sys/types.h>
     39 #include <sys/uio.h>
     40 #include <unistd.h>
     41 #include <fcntl.h>
     42 #include <ctype.h>
     43 #include <stdlib.h>
     44 #include <stdio.h>
     45 #include <syslog.h>
     46 #include <errno.h>
     47 #include <string.h>
     48 #include "pathnames.h"
     49 #include "prog_ops.h"
     50 
     51 #include "logit.h"
     52 
     53 #ifndef __UNCONST
     54 #define __UNCONST(a)		((void *)(unsigned long)(const void *)(a))
     55 #endif
     56 
     57 #ifndef BUFSIZ
     58 #define	BUFSIZ		1024
     59 #endif
     60 #define MAXHOP		32		/* max number of tc= indirections */
     61 
     62 #define	tgetent		agetent
     63 #define	tnchktc		anchktc
     64 #define	tnamatch	anamatch
     65 #define	tgetnum		agetnum
     66 #define	tgetflag	agetflag
     67 #define	tgetstr		agetstr
     68 
     69 #if 0
     70 #define V_TERMCAP	"REMOTE"
     71 #define V_TERM		"HOST"
     72 #endif
     73 
     74 char	*RM;
     75 
     76 /*
     77  * termcap - routines for dealing with the terminal capability data base
     78  *
     79  * BUG:		Should use a "last" pointer in tbuf, so that searching
     80  *		for capabilities alphabetically would not be a n**2/2
     81  *		process when large numbers of capabilities are given.
     82  * Note:	If we add a last pointer now we will screw up the
     83  *		tc capability. We really should compile termcap.
     84  *
     85  * Essentially all the work here is scanning and decoding escapes
     86  * in string capabilities.  We don't use stdio because the editor
     87  * doesn't, and because living w/o it is not hard.
     88  */
     89 
     90 static	char *tbuf;
     91 static	int hopcount;	/* detect infinite loops in termcap, init 0 */
     92 
     93 static	char *remotefile;
     94 
     95 extern char *conffile;
     96 
     97 int tgetent(char *, char *);
     98 int getent(char *, char *, char *);
     99 int tnchktc(void);
    100 int tnamatch(char *);
    101 static char *tskip(char *);
    102 int64_t tgetnum(char *);
    103 int tgetflag(char *);
    104 char *tgetstr(char *, char **);
    105 static char *tdecode(char *, char **);
    106 
    107 /*
    108  * Get an entry for terminal name in buffer bp,
    109  * from the termcap file.  Parse is very rudimentary;
    110  * we just notice escaped newlines.
    111  */
    112 int
    113 tgetent(char *bp, char *name)
    114 {
    115 	char *cp;
    116 
    117 	remotefile = cp = conffile ? conffile : __UNCONST(_PATH_RTADVDCONF);
    118 	return (getent(bp, name, cp));
    119 }
    120 
    121 int
    122 getent(char *bp, char *name, char *cp)
    123 {
    124 	int c;
    125 	int i = 0, cnt = 0;
    126 	char ibuf[BUFSIZ];
    127 	int tf;
    128 
    129 	tbuf = bp;
    130 	tf = 0;
    131 	/*
    132 	 * TERMCAP can have one of two things in it. It can be the
    133 	 * name of a file to use instead of /etc/termcap. In this
    134 	 * case it better start with a "/". Or it can be an entry to
    135 	 * use so we don't have to read the file. In this case it
    136 	 * has to already have the newlines crunched out.
    137 	 */
    138 	if (cp && *cp) {
    139 		tf = open(RM = cp, O_RDONLY);
    140 	}
    141 	if (tf < 0) {
    142 		logit(LOG_INFO, "%s: open `%s': %m", __func__, cp);
    143 		return (-2);
    144 	}
    145 	for (;;) {
    146 		cp = bp;
    147 		for (;;) {
    148 			if (i == cnt) {
    149 				cnt = read(tf, ibuf, BUFSIZ);
    150 				if (cnt <= 0) {
    151 					close(tf);
    152 					return (0);
    153 				}
    154 				i = 0;
    155 			}
    156 			c = ibuf[i++];
    157 			if (c == '\n') {
    158 				if (cp > bp && cp[-1] == '\\') {
    159 					cp--;
    160 					continue;
    161 				}
    162 				break;
    163 			}
    164 			if (cp >= bp + BUFSIZ) {
    165 				prog_write(2,"Remcap entry too long\n", 23);
    166 				break;
    167 			} else
    168 				*cp++ = c;
    169 		}
    170 		*cp = 0;
    171 
    172 		/*
    173 		 * The real work for the match.
    174 		 */
    175 		if (tnamatch(name)) {
    176 			close(tf);
    177 			return (tnchktc());
    178 		}
    179 	}
    180 }
    181 
    182 /*
    183  * tnchktc: check the last entry, see if it's tc=xxx. If so,
    184  * recursively find xxx and append that entry (minus the names)
    185  * to take the place of the tc=xxx entry. This allows termcap
    186  * entries to say "like an HP2621 but doesn't turn on the labels".
    187  * Note that this works because of the left to right scan.
    188  */
    189 int
    190 tnchktc(void)
    191 {
    192 	char *p, *q;
    193 	char tcname[16];	/* name of similar terminal */
    194 	char tcbuf[BUFSIZ];
    195 	char *holdtbuf = tbuf;
    196 	int l;
    197 
    198 	p = tbuf + strlen(tbuf) - 2;	/* before the last colon */
    199 	while (*--p != ':')
    200 		if (p < tbuf) {
    201 			prog_write(2, "Bad remcap entry\n", 18);
    202 			return (0);
    203 		}
    204 	p++;
    205 	/* p now points to beginning of last field */
    206 	if (p[0] != 't' || p[1] != 'c')
    207 		return (1);
    208 	strlcpy(tcname, p + 3, sizeof tcname);
    209 	q = tcname;
    210 	while (*q && *q != ':')
    211 		q++;
    212 	*q = 0;
    213 	if (++hopcount > MAXHOP) {
    214 		prog_write(2, "Infinite tc= loop\n", 18);
    215 		return (0);
    216 	}
    217 	if (getent(tcbuf, tcname, remotefile) != 1) {
    218 		return (0);
    219 	}
    220 	for (q = tcbuf; *q++ != ':'; )
    221 		;
    222 	l = p - holdtbuf + strlen(q);
    223 	if (l > BUFSIZ) {
    224 		prog_write(2, "Remcap entry too long\n", 23);
    225 		q[BUFSIZ - (p-holdtbuf)] = 0;
    226 	}
    227 	strcpy(p, q);
    228 	tbuf = holdtbuf;
    229 	return (1);
    230 }
    231 
    232 /*
    233  * Tnamatch deals with name matching.  The first field of the termcap
    234  * entry is a sequence of names separated by |'s, so we compare
    235  * against each such name.  The normal : terminator after the last
    236  * name (before the first field) stops us.
    237  */
    238 int
    239 tnamatch(char *np)
    240 {
    241 	char *Np, *Bp;
    242 
    243 	Bp = tbuf;
    244 	if (*Bp == '#')
    245 		return (0);
    246 	for (;;) {
    247 		for (Np = np; *Np && *Bp == *Np; Bp++, Np++)
    248 			continue;
    249 		if (*Np == 0 && (*Bp == '|' || *Bp == ':' || *Bp == 0))
    250 			return (1);
    251 		while (*Bp && *Bp != ':' && *Bp != '|')
    252 			Bp++;
    253 		if (*Bp == 0 || *Bp == ':')
    254 			return (0);
    255 		Bp++;
    256 	}
    257 }
    258 
    259 /*
    260  * Skip to the next field.  Notice that this is very dumb, not
    261  * knowing about \: escapes or any such.  If necessary, :'s can be put
    262  * into the termcap file in octal.
    263  */
    264 static char *
    265 tskip(char *bp)
    266 {
    267 	int dquote;
    268 
    269 	dquote = 0;
    270 	while (*bp) {
    271 		switch (*bp) {
    272 		case ':':
    273 			if (!dquote)
    274 				goto breakbreak;
    275 			else
    276 				bp++;
    277 			break;
    278 		case '\\':
    279 			bp++;
    280 			if (isdigit((unsigned char)*bp)) {
    281 				while (isdigit((unsigned char)*bp++))
    282 					;
    283 			} else
    284 				bp++;
    285 			/* FALLTHROUGH */
    286 		case '"':
    287 			dquote = (dquote ? 0 : 1);
    288 			bp++;
    289 			break;
    290 		default:
    291 			bp++;
    292 			break;
    293 		}
    294 	}
    295 breakbreak:
    296 	if (*bp == ':')
    297 		bp++;
    298 	return (bp);
    299 }
    300 
    301 /*
    302  * Return the (numeric) option id.
    303  * Numeric options look like
    304  *	li#80
    305  * i.e. the option string is separated from the numeric value by
    306  * a # character.  If the option is not found we return -1.
    307  * Note that we handle octal numbers beginning with 0.
    308  */
    309 int64_t
    310 tgetnum(char *id)
    311 {
    312 	int64_t i;
    313 	int base;
    314 	char *bp = tbuf;
    315 
    316 	for (;;) {
    317 		bp = tskip(bp);
    318 		if (*bp == 0)
    319 			return (-1);
    320 		if (strncmp(bp, id, strlen(id)) != 0)
    321 			continue;
    322 		bp += strlen(id);
    323 		if (*bp == '@')
    324 			return (-1);
    325 		if (*bp != '#')
    326 			continue;
    327 		bp++;
    328 		base = 10;
    329 		if (*bp == '0')
    330 			base = 8;
    331 		i = 0;
    332 		while (isdigit((unsigned char)*bp))
    333 			i *= base, i += *bp++ - '0';
    334 		return (i);
    335 	}
    336 }
    337 
    338 /*
    339  * Handle a flag option.
    340  * Flag options are given "naked", i.e. followed by a : or the end
    341  * of the buffer.  Return 1 if we find the option, or 0 if it is
    342  * not given.
    343  */
    344 int
    345 tgetflag(char *id)
    346 {
    347 	char *bp = tbuf;
    348 
    349 	for (;;) {
    350 		bp = tskip(bp);
    351 		if (!*bp)
    352 			return (0);
    353 		if (strncmp(bp, id, strlen(id)) == 0) {
    354 			bp += strlen(id);
    355 			if (!*bp || *bp == ':')
    356 				return (1);
    357 			else if (*bp == '@')
    358 				return (0);
    359 		}
    360 	}
    361 }
    362 
    363 /*
    364  * Get a string valued option.
    365  * These are given as
    366  *	cl=^Z
    367  * Much decoding is done on the strings, and the strings are
    368  * placed in area, which is a ref parameter which is updated.
    369  * No checking on area overflow.
    370  */
    371 char *
    372 tgetstr(char *id, char **area)
    373 {
    374 	char *bp = tbuf;
    375 
    376 	for (;;) {
    377 		bp = tskip(bp);
    378 		if (!*bp)
    379 			return (0);
    380 		if (strncmp(bp, id, strlen(id)) != 0)
    381 			continue;
    382 		bp += strlen(id);
    383 		if (*bp == '@')
    384 			return (0);
    385 		if (*bp != '=')
    386 			continue;
    387 		bp++;
    388 		return (tdecode(bp, area));
    389 	}
    390 }
    391 
    392 /*
    393  * Tdecode does the grung work to decode the
    394  * string capability escapes.
    395  */
    396 static char *
    397 tdecode(char *str, char **area)
    398 {
    399 	char *cp;
    400 	int c;
    401 	const char *dps = "E\033^^\\\\::n\nr\rt\tb\bf\f\"\"", *dp;
    402 	int i;
    403 	char term;
    404 
    405 	term = ':';
    406 	cp = *area;
    407 again:
    408 	if (*str == '"') {
    409 		term = '"';
    410 		str++;
    411 	}
    412 	while ((c = *str++) && c != term) {
    413 		switch (c) {
    414 
    415 		case '^':
    416 			c = *str++ & 037;
    417 			break;
    418 
    419 		case '\\':
    420 			dp = dps;
    421 			c = *str++;
    422 nextc:
    423 			if (*dp++ == c) {
    424 				c = *dp++;
    425 				break;
    426 			}
    427 			dp++;
    428 			if (*dp)
    429 				goto nextc;
    430 			if (isdigit((unsigned char)c)) {
    431 				c -= '0', i = 2;
    432 				do
    433 					c <<= 3, c |= *str++ - '0';
    434 				while (--i && isdigit((unsigned char)*str));
    435 			}
    436 			break;
    437 		}
    438 		*cp++ = c;
    439 	}
    440 	if (c == term && term != ':') {
    441 		term = ':';
    442 		goto again;
    443 	}
    444 	*cp++ = 0;
    445 	str = *area;
    446 	*area = cp;
    447 	return (str);
    448 }
    449