sbin/dhclient/conflex.c

   1 /*      $OpenBSD: src/sbin/dhclient/conflex.c,v 1.14 2011/12/10 17:36:40 krw Exp $      */
   2
   3 /* Lexical scanner for dhclient config file... */
   4
   5 /*
   6  * Copyright (c) 1995, 1996, 1997 The Internet Software Consortium.
   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  *
  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 Internet Software Consortium nor the names
  19  *    of its contributors may be used to endorse or promote products derived
  20  *    from this software without specific prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE INTERNET SOFTWARE CONSORTIUM AND
  23  * CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
  24  * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
  25  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  26  * DISCLAIMED.  IN NO EVENT SHALL THE INTERNET SOFTWARE CONSORTIUM OR
  27  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  28  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  29  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
  30  * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  31  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  32  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  33  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  34  * SUCH DAMAGE.
  35  *
  36  * This software has been written for the Internet Software Consortium
  37  * by Ted Lemon <mellon@fugue.com> in cooperation with Vixie
  38  * Enterprises.  To learn more about the Internet Software Consortium,
  39  * see ``http://www.vix.com/isc''.  To learn more about Vixie
  40  * Enterprises, see ``http://www.vix.com''.
  41  */
  42
  43 #include <ctype.h>
  44
  45 #include "dhcpd.h"
  46 #include "dhctoken.h"
  47
  48 int lexline;
  49 int lexchar;
  50 char *token_line;
  51 char *prev_line;
  52 char *cur_line;
  53 char *tlname;
  54
  55 static char line1[81];
  56 static char line2[81];
  57 static uint lpos;
  58 static int line;
  59 static int tlpos;
  60 static int tline;
  61 static int token;
  62 static int ugflag;
  63 static char *tval;
  64 static char tokbuf[1500];
  65
  66 static int get_char(FILE *);
  67 static int get_token(FILE *);
  68 static void skip_to_eol(FILE *);
  69 static int read_string(FILE *);
  70 static int read_number(int, FILE *);
  71 static int read_num_or_name(int, FILE *);
  72 int kw_cmp(const void *, const void *);
  73 static int intern(char *, int);
  74
  75 void
  76 new_parse(char *name)
  77 {
  78         /*
  79          * Initialize all parsing state, as we are starting to parse a
  80          * new file, 'name'.
  81          */
  82
  83         bzero(line1, sizeof(line1));
  84         bzero(line2, sizeof(line2));
  85         bzero(tokbuf, sizeof(tokbuf));
  86
  87         lpos = line = 1;
  88         tlpos = tline = token = ugflag = 0;
  89         tval = NULL;
  90
  91         lexline = lexchar = 0;
  92         cur_line = line1;
  93         prev_line = line2;
  94         token_line = cur_line;
  95         tlname = name;
  96
  97         warnings_occurred = 0;
  98 }
  99
 100 static int
 101 get_char(FILE *cfile)
 102 {
 103         int c = getc(cfile);
 104         if (!ugflag) {
 105                 if (c == '\n') {
 106                         if (cur_line == line1) {
 107                                 cur_line = line2;
 108                                 prev_line = line1;
 109                         } else {
 110                                 cur_line = line2;
 111                                 prev_line = line1;
 112                         }
 113                         line++;
 114                         lpos = 1;
 115                         cur_line[0] = 0;
 116                 } else if (c != EOF) {
 117                         if (lpos < sizeof(line1)) {
 118                                 cur_line[lpos - 1] = c;
 119                                 cur_line[lpos] = 0;
 120                         }
 121                         lpos++;
 122                 }
 123         } else
 124                 ugflag = 0;
 125         return (c);
 126 }
 127
 128 static int
 129 get_token(FILE *cfile)
 130 {
 131         int             c, ttok;
 132         static char     tb[2];
 133         int             l, p;
 134
 135         do {
 136                 l = line;
 137                 p = lpos;
 138
 139                 c = get_char(cfile);
 140
 141                 if (isascii(c) && isspace(c))
 142                         continue;
 143                 if (c == '#') {
 144                         skip_to_eol(cfile);
 145                         continue;
 146                 }
 147                 if (c == '"') {
 148                         lexline = l;
 149                         lexchar = p;
 150                         ttok = read_string(cfile);
 151                         break;
 152                 }
 153                 if ((isascii(c) && isdigit(c)) || c == '-') {
 154                         lexline = l;
 155                         lexchar = p;
 156                         ttok = read_number(c, cfile);
 157                         break;
 158                 } else if (isascii(c) && isalpha(c)) {
 159                         lexline = l;
 160                         lexchar = p;
 161                         ttok = read_num_or_name(c, cfile);
 162                         break;
 163                 } else {
 164                         lexline = l;
 165                         lexchar = p;
 166                         tb[0] = c;
 167                         tb[1] = 0;
 168                         tval = tb;
 169                         ttok = c;
 170                         break;
 171                 }
 172         } while (1);
 173         return (ttok);
 174 }
 175
 176 int
 177 next_token(char **rval, FILE *cfile)
 178 {
 179         int     rv;
 180
 181         if (token) {
 182                 if (lexline != tline)
 183                         token_line = cur_line;
 184                 lexchar = tlpos;
 185                 lexline = tline;
 186                 rv = token;
 187                 token = 0;
 188         } else {
 189                 rv = get_token(cfile);
 190                 token_line = cur_line;
 191         }
 192         if (rval)
 193                 *rval = tval;
 194
 195         return (rv);
 196 }
 197
 198 int
 199 peek_token(char **rval, FILE *cfile)
 200 {
 201         int     x;
 202
 203         if (!token) {
 204                 tlpos = lexchar;
 205                 tline = lexline;
 206                 token = get_token(cfile);
 207                 if (lexline != tline)
 208                         token_line = prev_line;
 209                 x = lexchar;
 210                 lexchar = tlpos;
 211                 tlpos = x;
 212                 x = lexline;
 213                 lexline = tline;
 214                 tline = x;
 215         }
 216         if (rval)
 217                 *rval = tval;
 218
 219         return (token);
 220 }
 221
 222 static void
 223 skip_to_eol(FILE *cfile)
 224 {
 225         int     c;
 226
 227         do {
 228                 c = get_char(cfile);
 229                 if (c == EOF)
 230                         return;
 231                 if (c == '\n')
 232                         return;
 233         } while (1);
 234 }
 235
 236 static int
 237 read_string(FILE *cfile)
 238 {
 239         uint    i;
 240         int     c, bs = 0;
 241
 242         for (i = 0; i < sizeof(tokbuf); i++) {
 243                 c = get_char(cfile);
 244                 if (c == EOF) {
 245                         parse_warn("eof in string constant");
 246                         break;
 247                 }
 248                 if (bs) {
 249                         bs = 0;
 250                         tokbuf[i] = c;
 251                 } else if (c == '\\')
 252                         bs = 1;
 253                 else if (c == '"')
 254                         break;
 255                 else
 256                         tokbuf[i] = c;
 257         }
 258         /*
 259          * Normally, I'd feel guilty about this, but we're talking about
 260          * strings that'll fit in a DHCP packet here...
 261          */
 262         if (i == sizeof(tokbuf)) {
 263                 parse_warn("string constant larger than internal buffer");
 264                 i--;
 265         }
 266         tokbuf[i] = 0;
 267         tval = tokbuf;
 268         return (TOK_STRING);
 269 }
 270
 271 static int
 272 read_number(int c, FILE *cfile)
 273 {
 274         uint    i = 0;
 275         int     seenx = 0, token = TOK_NUMBER;
 276
 277         tokbuf[i++] = c;
 278         for (; i < sizeof(tokbuf); i++) {
 279                 c = get_char(cfile);
 280                 if (!seenx && c == 'x')
 281                         seenx = 1;
 282                 else if (!isascii(c) || !isxdigit(c)) {
 283                         ungetc(c, cfile);
 284                         ugflag = 1;
 285                         break;
 286                 }
 287                 tokbuf[i] = c;
 288         }
 289         if (i == sizeof(tokbuf)) {
 290                 parse_warn("numeric token larger than internal buffer");
 291                 i--;
 292         }
 293         tokbuf[i] = 0;
 294         tval = tokbuf;
 295
 296         return (token);
 297 }
 298
 299 static int
 300 read_num_or_name(int c, FILE *cfile)
 301 {
 302         uint    i = 0;
 303         int     rv = TOK_NUMBER_OR_NAME;
 304
 305         tokbuf[i++] = c;
 306         for (; i < sizeof(tokbuf); i++) {
 307                 c = get_char(cfile);
 308                 if (!isascii(c) || (c != '-' && c != '_' && !isalnum(c))) {
 309                         ungetc(c, cfile);
 310                         ugflag = 1;
 311                         break;
 312                 }
 313                 if (!isxdigit(c))
 314                         rv = TOK_NAME;
 315                 tokbuf[i] = c;
 316         }
 317         if (i == sizeof(tokbuf)) {
 318                 parse_warn("token larger than internal buffer");
 319                 i--;
 320         }
 321         tokbuf[i] = 0;
 322         tval = tokbuf;
 323
 324         return (intern(tval, rv));
 325 }
 326
 327 static const struct keywords {
 328         const char      *k_name;
 329         int             k_val;
 330 } keywords[] = {
 331         { "alias",                              TOK_ALIAS },
 332         { "append",                             TOK_APPEND },
 333         { "backoff-cutoff",                     TOK_BACKOFF_CUTOFF },
 334         { "bootp",                              TOK_BOOTP },
 335         { "default",                            TOK_DEFAULT },
 336         { "deny",                               TOK_DENY },
 337         { "ethernet",                           TOK_ETHERNET },
 338         { "expire",                             TOK_EXPIRE },
 339         { "fddi",                               TOK_FDDI },
 340         { "filename",                           TOK_FILENAME },
 341         { "fixed-address",                      TOK_FIXED_ADDR },
 342         { "hardware",                           TOK_HARDWARE },
 343         { "initial-interval",                   TOK_INITIAL_INTERVAL },
 344         { "interface",                          TOK_INTERFACE },
 345         { "lease",                              TOK_LEASE },
 346         { "link-timeout",                       TOK_LINK_TIMEOUT },
 347         { "media",                              TOK_MEDIA },
 348         { "medium",                             TOK_MEDIUM },
 349         { "option",                             TOK_OPTION },
 350         { "prepend",                            TOK_PREPEND },
 351         { "rebind",                             TOK_REBIND },
 352         { "reboot",                             TOK_REBOOT },
 353         { "reject",                             TOK_REJECT },
 354         { "renew",                              TOK_RENEW },
 355         { "request",                            TOK_REQUEST },
 356         { "require",                            TOK_REQUIRE },
 357         { "retry",                              TOK_RETRY },
 358         { "script",                             TOK_SCRIPT },
 359         { "select-timeout",                     TOK_SELECT_TIMEOUT },
 360         { "send",                               TOK_SEND },
 361         { "server-name",                        TOK_SERVER_NAME },
 362         { "supersede",                          TOK_SUPERSEDE },
 363         { "timeout",                            TOK_TIMEOUT },
 364         { "token-ring",                         TOK_TOKEN_RING }
 365 };
 366
 367 int
 368 kw_cmp(const void *k, const void *e)
 369 {
 370         return (strcasecmp(k, ((const struct keywords *)e)->k_name));
 371 }
 372
 373 static int
 374 intern(char *atom, int dfv)
 375 {
 376         const struct keywords *p;
 377
 378         p = bsearch(atom, keywords, sizeof(keywords)/sizeof(keywords[0]),
 379             sizeof(keywords[0]), kw_cmp);
 380         if (p)
 381                 return (p->k_val);
 382         return (dfv);
 383 }