usr.sbin/rtadvd/advcap.c

   1 /*      $NetBSD: advcap.c,v 1.15 2015/06/05 15:41:59 roy 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
  50 #ifndef __UNCONST
  51 #define __UNCONST(a)            ((void *)(unsigned long)(const void *)(a))
  52 #endif
  53
  54 #ifndef BUFSIZ
  55 #define BUFSIZ          1024
  56 #endif
  57 #define MAXHOP          32              /* max number of tc= indirections */
  58
  59 #define tgetent         agetent
  60 #define tnchktc         anchktc
  61 #define tnamatch        anamatch
  62 #define tgetnum         agetnum
  63 #define tgetflag        agetflag
  64 #define tgetstr         agetstr
  65
  66 #if 0
  67 #define V_TERMCAP       "REMOTE"
  68 #define V_TERM          "HOST"
  69 #endif
  70
  71 char    *RM;
  72
  73 /*
  74  * termcap - routines for dealing with the terminal capability data base
  75  *
  76  * BUG:         Should use a "last" pointer in tbuf, so that searching
  77  *              for capabilities alphabetically would not be a n**2/2
  78  *              process when large numbers of capabilities are given.
  79  * Note:        If we add a last pointer now we will screw up the
  80  *              tc capability. We really should compile termcap.
  81  *
  82  * Essentially all the work here is scanning and decoding escapes
  83  * in string capabilities.  We don't use stdio because the editor
  84  * doesn't, and because living w/o it is not hard.
  85  */
  86
  87 static  char *tbuf;
  88 static  int hopcount;   /* detect infinite loops in termcap, init 0 */
  89
  90 static  char *remotefile;
  91
  92 extern char *conffile;
  93
  94 int tgetent(char *, char *);
  95 int getent(char *, char *, char *);
  96 int tnchktc(void);
  97 int tnamatch(char *);
  98 static char *tskip(char *);
  99 int64_t tgetnum(char *);
 100 int tgetflag(char *);
 101 char *tgetstr(char *, char **);
 102 static char *tdecode(char *, char **);
 103
 104 /*
 105  * Get an entry for terminal name in buffer bp,
 106  * from the termcap file.  Parse is very rudimentary;
 107  * we just notice escaped newlines.
 108  */
 109 int
 110 tgetent(char *bp, char *name)
 111 {
 112         char *cp;
 113
 114         remotefile = cp = conffile ? conffile : __UNCONST(_PATH_RTADVDCONF);
 115         return (getent(bp, name, cp));
 116 }
 117
 118 int
 119 getent(char *bp, char *name, char *cp)
 120 {
 121         int c;
 122         int i = 0, cnt = 0;
 123         char ibuf[BUFSIZ];
 124         int tf;
 125
 126         tbuf = bp;
 127         tf = 0;
 128         /*
 129          * TERMCAP can have one of two things in it. It can be the
 130          * name of a file to use instead of /etc/termcap. In this
 131          * case it better start with a "/". Or it can be an entry to
 132          * use so we don't have to read the file. In this case it
 133          * has to already have the newlines crunched out.
 134          */
 135         if (cp && *cp) {
 136                 tf = open(RM = cp, O_RDONLY);
 137         }
 138         if (tf < 0) {
 139                 syslog(LOG_INFO, "<%s> open: %m", __func__);
 140                 return (-2);
 141         }
 142         for (;;) {
 143                 cp = bp;
 144                 for (;;) {
 145                         if (i == cnt) {
 146                                 cnt = read(tf, ibuf, BUFSIZ);
 147                                 if (cnt <= 0) {
 148                                         close(tf);
 149                                         return (0);
 150                                 }
 151                                 i = 0;
 152                         }
 153                         c = ibuf[i++];
 154                         if (c == '\n') {
 155                                 if (cp > bp && cp[-1] == '\\') {
 156                                         cp--;
 157                                         continue;
 158                                 }
 159                                 break;
 160                         }
 161                         if (cp >= bp + BUFSIZ) {
 162                                 write(2,"Remcap entry too long\n", 23);
 163                                 break;
 164                         } else
 165                                 *cp++ = c;
 166                 }
 167                 *cp = 0;
 168
 169                 /*
 170                  * The real work for the match.
 171                  */
 172                 if (tnamatch(name)) {
 173                         close(tf);
 174                         return (tnchktc());
 175                 }
 176         }
 177 }
 178
 179 /*
 180  * tnchktc: check the last entry, see if it's tc=xxx. If so,
 181  * recursively find xxx and append that entry (minus the names)
 182  * to take the place of the tc=xxx entry. This allows termcap
 183  * entries to say "like an HP2621 but doesn't turn on the labels".
 184  * Note that this works because of the left to right scan.
 185  */
 186 int
 187 tnchktc(void)
 188 {
 189         char *p, *q;
 190         char tcname[16];        /* name of similar terminal */
 191         char tcbuf[BUFSIZ];
 192         char *holdtbuf = tbuf;
 193         int l;
 194
 195         p = tbuf + strlen(tbuf) - 2;    /* before the last colon */
 196         while (*--p != ':')
 197                 if (p < tbuf) {
 198                         write(2, "Bad remcap entry\n", 18);
 199                         return (0);
 200                 }
 201         p++;
 202         /* p now points to beginning of last field */
 203         if (p[0] != 't' || p[1] != 'c')
 204                 return (1);
 205         strlcpy(tcname, p + 3, sizeof tcname);
 206         q = tcname;
 207         while (*q && *q != ':')
 208                 q++;
 209         *q = 0;
 210         if (++hopcount > MAXHOP) {
 211                 write(2, "Infinite tc= loop\n", 18);
 212                 return (0);
 213         }
 214         if (getent(tcbuf, tcname, remotefile) != 1) {
 215                 return (0);
 216         }
 217         for (q = tcbuf; *q++ != ':'; )
 218                 ;
 219         l = p - holdtbuf + strlen(q);
 220         if (l > BUFSIZ) {
 221                 write(2, "Remcap entry too long\n", 23);
 222                 q[BUFSIZ - (p-holdtbuf)] = 0;
 223         }
 224         strcpy(p, q);
 225         tbuf = holdtbuf;
 226         return (1);
 227 }
 228
 229 /*
 230  * Tnamatch deals with name matching.  The first field of the termcap
 231  * entry is a sequence of names separated by |'s, so we compare
 232  * against each such name.  The normal : terminator after the last
 233  * name (before the first field) stops us.
 234  */
 235 int
 236 tnamatch(char *np)
 237 {
 238         char *Np, *Bp;
 239
 240         Bp = tbuf;
 241         if (*Bp == '#')
 242                 return (0);
 243         for (;;) {
 244                 for (Np = np; *Np && *Bp == *Np; Bp++, Np++)
 245                         continue;
 246                 if (*Np == 0 && (*Bp == '|' || *Bp == ':' || *Bp == 0))
 247                         return (1);
 248                 while (*Bp && *Bp != ':' && *Bp != '|')
 249                         Bp++;
 250                 if (*Bp == 0 || *Bp == ':')
 251                         return (0);
 252                 Bp++;
 253         }
 254 }
 255
 256 /*
 257  * Skip to the next field.  Notice that this is very dumb, not
 258  * knowing about \: escapes or any such.  If necessary, :'s can be put
 259  * into the termcap file in octal.
 260  */
 261 static char *
 262 tskip(char *bp)
 263 {
 264         int dquote;
 265
 266         dquote = 0;
 267         while (*bp) {
 268                 switch (*bp) {
 269                 case ':':
 270                         if (!dquote)
 271                                 goto breakbreak;
 272                         else
 273                                 bp++;
 274                         break;
 275                 case '\\':
 276                         bp++;
 277                         if (isdigit((unsigned char)*bp)) {
 278                                 while (isdigit((unsigned char)*bp++))
 279                                         ;
 280                         } else
 281                                 bp++;
 282                 case '"':
 283                         dquote = (dquote ? 0 : 1);
 284                         bp++;
 285                         break;
 286                 default:
 287                         bp++;
 288                         break;
 289                 }
 290         }
 291 breakbreak:
 292         if (*bp == ':')
 293                 bp++;
 294         return (bp);
 295 }
 296
 297 /*
 298  * Return the (numeric) option id.
 299  * Numeric options look like
 300  *      li#80
 301  * i.e. the option string is separated from the numeric value by
 302  * a # character.  If the option is not found we return -1.
 303  * Note that we handle octal numbers beginning with 0.
 304  */
 305 int64_t
 306 tgetnum(char *id)
 307 {
 308         int64_t i;
 309         int base;
 310         char *bp = tbuf;
 311
 312         for (;;) {
 313                 bp = tskip(bp);
 314                 if (*bp == 0)
 315                         return (-1);
 316                 if (strncmp(bp, id, strlen(id)) != 0)
 317                         continue;
 318                 bp += strlen(id);
 319                 if (*bp == '@')
 320                         return (-1);
 321                 if (*bp != '#')
 322                         continue;
 323                 bp++;
 324                 base = 10;
 325                 if (*bp == '0')
 326                         base = 8;
 327                 i = 0;
 328                 while (isdigit((unsigned char)*bp))
 329                         i *= base, i += *bp++ - '0';
 330                 return (i);
 331         }
 332 }
 333
 334 /*
 335  * Handle a flag option.
 336  * Flag options are given "naked", i.e. followed by a : or the end
 337  * of the buffer.  Return 1 if we find the option, or 0 if it is
 338  * not given.
 339  */
 340 int
 341 tgetflag(char *id)
 342 {
 343         char *bp = tbuf;
 344
 345         for (;;) {
 346                 bp = tskip(bp);
 347                 if (!*bp)
 348                         return (0);
 349                 if (strncmp(bp, id, strlen(id)) == 0) {
 350                         bp += strlen(id);
 351                         if (!*bp || *bp == ':')
 352                                 return (1);
 353                         else if (*bp == '@')
 354                                 return (0);
 355                 }
 356         }
 357 }
 358
 359 /*
 360  * Get a string valued option.
 361  * These are given as
 362  *      cl=^Z
 363  * Much decoding is done on the strings, and the strings are
 364  * placed in area, which is a ref parameter which is updated.
 365  * No checking on area overflow.
 366  */
 367 char *
 368 tgetstr(char *id, char **area)
 369 {
 370         char *bp = tbuf;
 371
 372         for (;;) {
 373                 bp = tskip(bp);
 374                 if (!*bp)
 375                         return (0);
 376                 if (strncmp(bp, id, strlen(id)) != 0)
 377                         continue;
 378                 bp += strlen(id);
 379                 if (*bp == '@')
 380                         return (0);
 381                 if (*bp != '=')
 382                         continue;
 383                 bp++;
 384                 return (tdecode(bp, area));
 385         }
 386 }
 387
 388 /*
 389  * Tdecode does the grung work to decode the
 390  * string capability escapes.
 391  */
 392 static char *
 393 tdecode(char *str, char **area)
 394 {
 395         char *cp;
 396         int c;
 397         const char *dps = "E\033^^\\\\::n\nr\rt\tb\bf\f\"\"", *dp;
 398         int i;
 399         char term;
 400
 401         term = ':';
 402         cp = *area;
 403 again:
 404         if (*str == '"') {
 405                 term = '"';
 406                 str++;
 407         }
 408         while ((c = *str++) && c != term) {
 409                 switch (c) {
 410
 411                 case '^':
 412                         c = *str++ & 037;
 413                         break;
 414
 415                 case '\\':
 416                         dp = dps;
 417                         c = *str++;
 418 nextc:
 419                         if (*dp++ == c) {
 420                                 c = *dp++;
 421                                 break;
 422                         }
 423                         dp++;
 424                         if (*dp)
 425                                 goto nextc;
 426                         if (isdigit((unsigned char)c)) {
 427                                 c -= '0', i = 2;
 428                                 do
 429                                         c <<= 3, c |= *str++ - '0';
 430                                 while (--i && isdigit((unsigned char)*str));
 431                         }
 432                         break;
 433                 }
 434                 *cp++ = c;
 435         }
 436         if (c == term && term != ':') {
 437                 term = ':';
 438                 goto again;
 439         }
 440         *cp++ = 0;
 441         str = *area;
 442         *area = cp;
 443         return (str);
 444 }