usr.sbin/rtadvd/advcap.c

   1 /*      $FreeBSD: stable/10/usr.sbin/rtadvd/advcap.c 222824 2011-06-07 15:40:17Z hrs $  */
   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 BUFSIZ
  51 #define BUFSIZ          1024
  52 #endif
  53 #define MAXHOP          32              /* max number of tc= indirections */
  54
  55 #define tgetent         agetent
  56 #define tnchktc         anchktc
  57 #define tnamatch        anamatch
  58 #define tgetnum         agetnum
  59 #define tgetflag        agetflag
  60 #define tgetstr         agetstr
  61
  62 #if 0
  63 #define V_TERMCAP       "REMOTE"
  64 #define V_TERM          "HOST"
  65 #endif
  66
  67 /*
  68  * termcap - routines for dealing with the terminal capability data base
  69  *
  70  * BUG:         Should use a "last" pointer in tbuf, so that searching
  71  *              for capabilities alphabetically would not be a n**2/2
  72  *              process when large numbers of capabilities are given.
  73  * Note:        If we add a last pointer now we will screw up the
  74  *              tc capability. We really should compile termcap.
  75  *
  76  * Essentially all the work here is scanning and decoding escapes
  77  * in string capabilities.  We don't use stdio because the editor
  78  * doesn't, and because living w/o it is not hard.
  79  */
  80
  81 static  char *tbuf;
  82 static  int hopcount;   /* detect infinite loops in termcap, init 0 */
  83
  84 extern const char *conffile;
  85
  86 int tgetent(char *, char *);
  87 int getent(char *, char *, const char *);
  88 int tnchktc(void);
  89 int tnamatch(char *);
  90 static char *tskip(char *);
  91 int64_t tgetnum(char *);
  92 int tgetflag(char *);
  93 char *tgetstr(char *, char **);
  94 static char *tdecode(char *, char **);
  95
  96 /*
  97  * Get an entry for terminal name in buffer bp,
  98  * from the termcap file.  Parse is very rudimentary;
  99  * we just notice escaped newlines.
 100  */
 101 int
 102 tgetent(char *bp, char *name)
 103 {
 104         return (getent(bp, name, conffile));
 105 }
 106
 107 int
 108 getent(char *bp, char *name, const char *cfile)
 109 {
 110         int c;
 111         int i = 0, cnt = 0;
 112         char ibuf[BUFSIZ];
 113         char *cp;
 114         int tf;
 115
 116         tbuf = bp;
 117         tf = 0;
 118         /*
 119          * TERMCAP can have one of two things in it. It can be the
 120          * name of a file to use instead of /etc/termcap. In this
 121          * case it better start with a "/". Or it can be an entry to
 122          * use so we don't have to read the file. In this case it
 123          * has to already have the newlines crunched out.
 124          */
 125         if (cfile && *cfile)
 126                 tf = open(cfile, O_RDONLY);
 127
 128         if (tf < 0) {
 129                 syslog(LOG_INFO,
 130                        "<%s> open: %s", __func__, strerror(errno));
 131                 return (-2);
 132         }
 133         for (;;) {
 134                 cp = bp;
 135                 for (;;) {
 136                         if (i == cnt) {
 137                                 cnt = read(tf, ibuf, BUFSIZ);
 138                                 if (cnt <= 0) {
 139                                         close(tf);
 140                                         return (0);
 141                                 }
 142                                 i = 0;
 143                         }
 144                         c = ibuf[i++];
 145                         if (c == '\n') {
 146                                 if (cp > bp && cp[-1] == '\\') {
 147                                         cp--;
 148                                         continue;
 149                                 }
 150                                 break;
 151                         }
 152                         if (cp >= bp + BUFSIZ) {
 153                                 write(STDERR_FILENO, "Remcap entry too long\n",
 154                                       23);
 155                                 break;
 156                         } else
 157                                 *cp++ = c;
 158                 }
 159                 *cp = 0;
 160
 161                 /*
 162                  * The real work for the match.
 163                  */
 164                 if (tnamatch(name)) {
 165                         close(tf);
 166                         return (tnchktc());
 167                 }
 168         }
 169 }
 170
 171 /*
 172  * tnchktc: check the last entry, see if it's tc=xxx. If so,
 173  * recursively find xxx and append that entry (minus the names)
 174  * to take the place of the tc=xxx entry. This allows termcap
 175  * entries to say "like an HP2621 but doesn't turn on the labels".
 176  * Note that this works because of the left to right scan.
 177  */
 178 int
 179 tnchktc(void)
 180 {
 181         char *p, *q;
 182         char tcname[16];        /* name of similar terminal */
 183         char tcbuf[BUFSIZ];
 184         char *holdtbuf = tbuf;
 185         int l;
 186
 187         p = tbuf + strlen(tbuf) - 2;    /* before the last colon */
 188         while (*--p != ':')
 189                 if (p < tbuf) {
 190                         write(STDERR_FILENO, "Bad remcap entry\n", 18);
 191                         return (0);
 192                 }
 193         p++;
 194         /* p now points to beginning of last field */
 195         if (p[0] != 't' || p[1] != 'c')
 196                 return (1);
 197         strlcpy(tcname, p + 3, sizeof tcname);
 198         q = tcname;
 199         while (*q && *q != ':')
 200                 q++;
 201         *q = 0;
 202         if (++hopcount > MAXHOP) {
 203                 write(STDERR_FILENO, "Infinite tc= loop\n", 18);
 204                 return (0);
 205         }
 206         if (getent(tcbuf, tcname, conffile) != 1) {
 207                 return (0);
 208         }
 209         for (q = tcbuf; *q++ != ':'; )
 210                 ;
 211         l = p - holdtbuf + strlen(q);
 212         if (l > BUFSIZ) {
 213                 write(STDERR_FILENO, "Remcap entry too long\n", 23);
 214                 q[BUFSIZ - (p-holdtbuf)] = 0;
 215         }
 216         strcpy(p, q);
 217         tbuf = holdtbuf;
 218         return (1);
 219 }
 220
 221 /*
 222  * Tnamatch deals with name matching.  The first field of the termcap
 223  * entry is a sequence of names separated by |'s, so we compare
 224  * against each such name.  The normal : terminator after the last
 225  * name (before the first field) stops us.
 226  */
 227 int
 228 tnamatch(char *np)
 229 {
 230         char *Np, *Bp;
 231
 232         Bp = tbuf;
 233         if (*Bp == '#')
 234                 return (0);
 235         for (;;) {
 236                 for (Np = np; *Np && *Bp == *Np; Bp++, Np++)
 237                         continue;
 238                 if (*Np == 0 && (*Bp == '|' || *Bp == ':' || *Bp == 0))
 239                         return (1);
 240                 while (*Bp && *Bp != ':' && *Bp != '|')
 241                         Bp++;
 242                 if (*Bp == 0 || *Bp == ':')
 243                         return (0);
 244                 Bp++;
 245         }
 246 }
 247
 248 /*
 249  * Skip to the next field.  Notice that this is very dumb, not
 250  * knowing about \: escapes or any such.  If necessary, :'s can be put
 251  * into the termcap file in octal.
 252  */
 253 static char *
 254 tskip(char *bp)
 255 {
 256         int dquote;
 257
 258         dquote = 0;
 259         while (*bp) {
 260                 switch (*bp) {
 261                 case ':':
 262                         if (!dquote)
 263                                 goto breakbreak;
 264                         else
 265                                 bp++;
 266                         break;
 267                 case '\\':
 268                         bp++;
 269                         if (isdigit(*bp)) {
 270                                 while (isdigit(*bp++))
 271                                         ;
 272                         } else
 273                                 bp++;
 274                 case '"':
 275                         dquote = (dquote ? 1 : 0);
 276                         bp++;
 277                         break;
 278                 default:
 279                         bp++;
 280                         break;
 281                 }
 282         }
 283 breakbreak:
 284         if (*bp == ':')
 285                 bp++;
 286         return (bp);
 287 }
 288
 289 /*
 290  * Return the (numeric) option id.
 291  * Numeric options look like
 292  *      li#80
 293  * i.e. the option string is separated from the numeric value by
 294  * a # character.  If the option is not found we return -1.
 295  * Note that we handle octal numbers beginning with 0.
 296  */
 297 int64_t
 298 tgetnum(char *id)
 299 {
 300         int64_t i;
 301         int base;
 302         char *bp = tbuf;
 303
 304         for (;;) {
 305                 bp = tskip(bp);
 306                 if (*bp == 0)
 307                         return (-1);
 308                 if (strncmp(bp, id, strlen(id)) != 0)
 309                         continue;
 310                 bp += strlen(id);
 311                 if (*bp == '@')
 312                         return (-1);
 313                 if (*bp != '#')
 314                         continue;
 315                 bp++;
 316                 base = 10;
 317                 if (*bp == '0')
 318                         base = 8;
 319                 i = 0;
 320                 while (isdigit(*bp))
 321                         i *= base, i += *bp++ - '0';
 322                 return (i);
 323         }
 324 }
 325
 326 /*
 327  * Handle a flag option.
 328  * Flag options are given "naked", i.e. followed by a : or the end
 329  * of the buffer.  Return 1 if we find the option, or 0 if it is
 330  * not given.
 331  */
 332 int
 333 tgetflag(char *id)
 334 {
 335         char *bp = tbuf;
 336
 337         for (;;) {
 338                 bp = tskip(bp);
 339                 if (!*bp)
 340                         return (0);
 341                 if (strncmp(bp, id, strlen(id)) == 0) {
 342                         bp += strlen(id);
 343                         if (!*bp || *bp == ':')
 344                                 return (1);
 345                         else if (*bp == '@')
 346                                 return (0);
 347                 }
 348         }
 349 }
 350
 351 /*
 352  * Get a string valued option.
 353  * These are given as
 354  *      cl=^Z
 355  * Much decoding is done on the strings, and the strings are
 356  * placed in area, which is a ref parameter which is updated.
 357  * No checking on area overflow.
 358  */
 359 char *
 360 tgetstr(char *id, char **area)
 361 {
 362         char *bp = tbuf;
 363
 364         for (;;) {
 365                 bp = tskip(bp);
 366                 if (!*bp)
 367                         return (0);
 368                 if (strncmp(bp, id, strlen(id)) != 0)
 369                         continue;
 370                 bp += strlen(id);
 371                 if (*bp == '@')
 372                         return (0);
 373                 if (*bp != '=')
 374                         continue;
 375                 bp++;
 376                 return (tdecode(bp, area));
 377         }
 378 }
 379
 380 /*
 381  * Tdecode does the grung work to decode the
 382  * string capability escapes.
 383  */
 384 static char *
 385 tdecode(char *str, char **area)
 386 {
 387         char *cp;
 388         int c;
 389         const char *dp;
 390         int i;
 391         char term;
 392
 393         term = ':';
 394         cp = *area;
 395 again:
 396         if (*str == '"') {
 397                 term = '"';
 398                 str++;
 399         }
 400         while ((c = *str++) && c != term) {
 401                 switch (c) {
 402
 403                 case '^':
 404                         c = *str++ & 037;
 405                         break;
 406
 407                 case '\\':
 408                         dp = "E\033^^\\\\::n\nr\rt\tb\bf\f\"\"";
 409                         c = *str++;
 410 nextc:
 411                         if (*dp++ == c) {
 412                                 c = *dp++;
 413                                 break;
 414                         }
 415                         dp++;
 416                         if (*dp)
 417                                 goto nextc;
 418                         if (isdigit(c)) {
 419                                 c -= '0', i = 2;
 420                                 do
 421                                         c <<= 3, c |= *str++ - '0';
 422                                 while (--i && isdigit(*str));
 423                         }
 424                         break;
 425                 }
 426                 *cp++ = c;
 427         }
 428         if (c == term && term != ':') {
 429                 term = ':';
 430                 goto again;
 431         }
 432         *cp++ = 0;
 433         str = *area;
 434         *area = cp;
 435         return (str);
 436 }