1 /* $NetBSD: unvis.c,v 1.45 2022/04/19 20:32:15 rillig Exp $ */ 2 3 /*- 4 * Copyright (c) 1989, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. Neither the name of the University nor the names of its contributors 16 * may be used to endorse or promote products derived from this software 17 * without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 */ 31 32 #include <sys/cdefs.h> 33 #if defined(LIBC_SCCS) && !defined(lint) 34 #if 0 35 static char sccsid[] = "@(#)unvis.c 8.1 (Berkeley) 6/4/93"; 36 #else 37 __RCSID("$NetBSD: unvis.c,v 1.45 2022/04/19 20:32:15 rillig Exp $"); 38 #endif 39 #endif /* LIBC_SCCS and not lint */ 40 41 #include "namespace.h" 42 #include <sys/types.h> 43 44 #include <assert.h> 45 #include <ctype.h> 46 #include <stdint.h> 47 #include <stdio.h> 48 #include <errno.h> 49 #include <vis.h> 50 51 #define _DIAGASSERT(x) assert(x) 52 53 /* 54 * Return the number of elements in a statically-allocated array, 55 * __x. 56 */ 57 #define __arraycount(__x) (sizeof(__x) / sizeof(__x[0])) 58 59 #ifdef __weak_alias 60 __weak_alias(strnunvisx,_strnunvisx) 61 #endif 62 63 #if !HAVE_VIS 64 /* 65 * decode driven by state machine 66 */ 67 #define S_GROUND 0 /* haven't seen escape char */ 68 #define S_START 1 /* start decoding special sequence */ 69 #define S_META 2 /* metachar started (M) */ 70 #define S_META1 3 /* metachar more, regular char (-) */ 71 #define S_CTRL 4 /* control char started (^) */ 72 #define S_OCTAL2 5 /* octal digit 2 */ 73 #define S_OCTAL3 6 /* octal digit 3 */ 74 #define S_HEX 7 /* mandatory hex digit */ 75 #define S_HEX1 8 /* http hex digit */ 76 #define S_HEX2 9 /* http hex digit 2 */ 77 #define S_MIME1 10 /* mime hex digit 1 */ 78 #define S_MIME2 11 /* mime hex digit 2 */ 79 #define S_EATCRNL 12 /* mime eating CRNL */ 80 #define S_AMP 13 /* seen & */ 81 #define S_NUMBER 14 /* collecting number */ 82 #define S_STRING 15 /* collecting string */ 83 84 #define isoctal(c) (((u_char)(c)) >= '0' && ((u_char)(c)) <= '7') 85 #define xtod(c) (isdigit(c) ? (c - '0') : ((tolower(c) - 'a') + 10)) 86 #define XTOD(c) (isdigit(c) ? (c - '0') : ((c - 'A') + 10)) 87 88 /* 89 * RFC 1866 90 */ 91 static const struct nv { 92 char name[7]; 93 uint8_t value; 94 } nv[] = { 95 { "AElig", 198 }, /* capital AE diphthong (ligature) */ 96 { "Aacute", 193 }, /* capital A, acute accent */ 97 { "Acirc", 194 }, /* capital A, circumflex accent */ 98 { "Agrave", 192 }, /* capital A, grave accent */ 99 { "Aring", 197 }, /* capital A, ring */ 100 { "Atilde", 195 }, /* capital A, tilde */ 101 { "Auml", 196 }, /* capital A, dieresis or umlaut mark */ 102 { "Ccedil", 199 }, /* capital C, cedilla */ 103 { "ETH", 208 }, /* capital Eth, Icelandic */ 104 { "Eacute", 201 }, /* capital E, acute accent */ 105 { "Ecirc", 202 }, /* capital E, circumflex accent */ 106 { "Egrave", 200 }, /* capital E, grave accent */ 107 { "Euml", 203 }, /* capital E, dieresis or umlaut mark */ 108 { "Iacute", 205 }, /* capital I, acute accent */ 109 { "Icirc", 206 }, /* capital I, circumflex accent */ 110 { "Igrave", 204 }, /* capital I, grave accent */ 111 { "Iuml", 207 }, /* capital I, dieresis or umlaut mark */ 112 { "Ntilde", 209 }, /* capital N, tilde */ 113 { "Oacute", 211 }, /* capital O, acute accent */ 114 { "Ocirc", 212 }, /* capital O, circumflex accent */ 115 { "Ograve", 210 }, /* capital O, grave accent */ 116 { "Oslash", 216 }, /* capital O, slash */ 117 { "Otilde", 213 }, /* capital O, tilde */ 118 { "Ouml", 214 }, /* capital O, dieresis or umlaut mark */ 119 { "THORN", 222 }, /* capital THORN, Icelandic */ 120 { "Uacute", 218 }, /* capital U, acute accent */ 121 { "Ucirc", 219 }, /* capital U, circumflex accent */ 122 { "Ugrave", 217 }, /* capital U, grave accent */ 123 { "Uuml", 220 }, /* capital U, dieresis or umlaut mark */ 124 { "Yacute", 221 }, /* capital Y, acute accent */ 125 { "aacute", 225 }, /* small a, acute accent */ 126 { "acirc", 226 }, /* small a, circumflex accent */ 127 { "acute", 180 }, /* acute accent */ 128 { "aelig", 230 }, /* small ae diphthong (ligature) */ 129 { "agrave", 224 }, /* small a, grave accent */ 130 { "amp", 38 }, /* ampersand */ 131 { "aring", 229 }, /* small a, ring */ 132 { "atilde", 227 }, /* small a, tilde */ 133 { "auml", 228 }, /* small a, dieresis or umlaut mark */ 134 { "brvbar", 166 }, /* broken (vertical) bar */ 135 { "ccedil", 231 }, /* small c, cedilla */ 136 { "cedil", 184 }, /* cedilla */ 137 { "cent", 162 }, /* cent sign */ 138 { "copy", 169 }, /* copyright sign */ 139 { "curren", 164 }, /* general currency sign */ 140 { "deg", 176 }, /* degree sign */ 141 { "divide", 247 }, /* divide sign */ 142 { "eacute", 233 }, /* small e, acute accent */ 143 { "ecirc", 234 }, /* small e, circumflex accent */ 144 { "egrave", 232 }, /* small e, grave accent */ 145 { "eth", 240 }, /* small eth, Icelandic */ 146 { "euml", 235 }, /* small e, dieresis or umlaut mark */ 147 { "frac12", 189 }, /* fraction one-half */ 148 { "frac14", 188 }, /* fraction one-quarter */ 149 { "frac34", 190 }, /* fraction three-quarters */ 150 { "gt", 62 }, /* greater than */ 151 { "iacute", 237 }, /* small i, acute accent */ 152 { "icirc", 238 }, /* small i, circumflex accent */ 153 { "iexcl", 161 }, /* inverted exclamation mark */ 154 { "igrave", 236 }, /* small i, grave accent */ 155 { "iquest", 191 }, /* inverted question mark */ 156 { "iuml", 239 }, /* small i, dieresis or umlaut mark */ 157 { "laquo", 171 }, /* angle quotation mark, left */ 158 { "lt", 60 }, /* less than */ 159 { "macr", 175 }, /* macron */ 160 { "micro", 181 }, /* micro sign */ 161 { "middot", 183 }, /* middle dot */ 162 { "nbsp", 160 }, /* no-break space */ 163 { "not", 172 }, /* not sign */ 164 { "ntilde", 241 }, /* small n, tilde */ 165 { "oacute", 243 }, /* small o, acute accent */ 166 { "ocirc", 244 }, /* small o, circumflex accent */ 167 { "ograve", 242 }, /* small o, grave accent */ 168 { "ordf", 170 }, /* ordinal indicator, feminine */ 169 { "ordm", 186 }, /* ordinal indicator, masculine */ 170 { "oslash", 248 }, /* small o, slash */ 171 { "otilde", 245 }, /* small o, tilde */ 172 { "ouml", 246 }, /* small o, dieresis or umlaut mark */ 173 { "para", 182 }, /* pilcrow (paragraph sign) */ 174 { "plusmn", 177 }, /* plus-or-minus sign */ 175 { "pound", 163 }, /* pound sterling sign */ 176 { "quot", 34 }, /* double quote */ 177 { "raquo", 187 }, /* angle quotation mark, right */ 178 { "reg", 174 }, /* registered sign */ 179 { "sect", 167 }, /* section sign */ 180 { "shy", 173 }, /* soft hyphen */ 181 { "sup1", 185 }, /* superscript one */ 182 { "sup2", 178 }, /* superscript two */ 183 { "sup3", 179 }, /* superscript three */ 184 { "szlig", 223 }, /* small sharp s, German (sz ligature) */ 185 { "thorn", 254 }, /* small thorn, Icelandic */ 186 { "times", 215 }, /* multiply sign */ 187 { "uacute", 250 }, /* small u, acute accent */ 188 { "ucirc", 251 }, /* small u, circumflex accent */ 189 { "ugrave", 249 }, /* small u, grave accent */ 190 { "uml", 168 }, /* umlaut (dieresis) */ 191 { "uuml", 252 }, /* small u, dieresis or umlaut mark */ 192 { "yacute", 253 }, /* small y, acute accent */ 193 { "yen", 165 }, /* yen sign */ 194 { "yuml", 255 }, /* small y, dieresis or umlaut mark */ 195 }; 196 197 /* 198 * unvis - decode characters previously encoded by vis 199 */ 200 int 201 unvis(char *cp, int c, int *astate, int flag) 202 { 203 unsigned char uc = (unsigned char)c; 204 unsigned char st, ia, is, lc; 205 206 /* 207 * Bottom 8 bits of astate hold the state machine state. 208 * Top 8 bits hold the current character in the http 1866 nv string decoding 209 */ 210 #define GS(a) ((a) & 0xff) 211 #define SS(a, b) (((uint32_t)(a) << 24) | (b)) 212 #define GI(a) ((uint32_t)(a) >> 24) 213 214 _DIAGASSERT(cp != NULL); 215 _DIAGASSERT(astate != NULL); 216 st = GS(*astate); 217 218 if (flag & UNVIS_END) { 219 switch (st) { 220 case S_OCTAL2: 221 case S_OCTAL3: 222 case S_HEX2: 223 *astate = SS(0, S_GROUND); 224 return UNVIS_VALID; 225 case S_GROUND: 226 return UNVIS_NOCHAR; 227 default: 228 return UNVIS_SYNBAD; 229 } 230 } 231 232 switch (st) { 233 234 case S_GROUND: 235 *cp = 0; 236 if ((flag & VIS_NOESCAPE) == 0 && c == '\\') { 237 *astate = SS(0, S_START); 238 return UNVIS_NOCHAR; 239 } 240 if ((flag & VIS_HTTP1808) && c == '%') { 241 *astate = SS(0, S_HEX1); 242 return UNVIS_NOCHAR; 243 } 244 if ((flag & VIS_HTTP1866) && c == '&') { 245 *astate = SS(0, S_AMP); 246 return UNVIS_NOCHAR; 247 } 248 if ((flag & VIS_MIMESTYLE) && c == '=') { 249 *astate = SS(0, S_MIME1); 250 return UNVIS_NOCHAR; 251 } 252 *cp = c; 253 return UNVIS_VALID; 254 255 case S_START: 256 switch(c) { 257 case '\\': 258 *cp = c; 259 *astate = SS(0, S_GROUND); 260 return UNVIS_VALID; 261 case '0': case '1': case '2': case '3': 262 case '4': case '5': case '6': case '7': 263 *cp = (c - '0'); 264 *astate = SS(0, S_OCTAL2); 265 return UNVIS_NOCHAR; 266 case 'M': 267 *cp = (char)0200; 268 *astate = SS(0, S_META); 269 return UNVIS_NOCHAR; 270 case '^': 271 *astate = SS(0, S_CTRL); 272 return UNVIS_NOCHAR; 273 case 'n': 274 *cp = '\n'; 275 *astate = SS(0, S_GROUND); 276 return UNVIS_VALID; 277 case 'r': 278 *cp = '\r'; 279 *astate = SS(0, S_GROUND); 280 return UNVIS_VALID; 281 case 'b': 282 *cp = '\b'; 283 *astate = SS(0, S_GROUND); 284 return UNVIS_VALID; 285 case 'a': 286 *cp = '\007'; 287 *astate = SS(0, S_GROUND); 288 return UNVIS_VALID; 289 case 'v': 290 *cp = '\v'; 291 *astate = SS(0, S_GROUND); 292 return UNVIS_VALID; 293 case 't': 294 *cp = '\t'; 295 *astate = SS(0, S_GROUND); 296 return UNVIS_VALID; 297 case 'f': 298 *cp = '\f'; 299 *astate = SS(0, S_GROUND); 300 return UNVIS_VALID; 301 case 's': 302 *cp = ' '; 303 *astate = SS(0, S_GROUND); 304 return UNVIS_VALID; 305 case 'E': 306 *cp = '\033'; 307 *astate = SS(0, S_GROUND); 308 return UNVIS_VALID; 309 case 'x': 310 *astate = SS(0, S_HEX); 311 return UNVIS_NOCHAR; 312 case '\n': 313 /* 314 * hidden newline 315 */ 316 *astate = SS(0, S_GROUND); 317 return UNVIS_NOCHAR; 318 case '$': 319 /* 320 * hidden marker 321 */ 322 *astate = SS(0, S_GROUND); 323 return UNVIS_NOCHAR; 324 default: 325 if (isgraph(c)) { 326 *cp = c; 327 *astate = SS(0, S_GROUND); 328 return UNVIS_VALID; 329 } 330 } 331 goto bad; 332 333 case S_META: 334 if (c == '-') 335 *astate = SS(0, S_META1); 336 else if (c == '^') 337 *astate = SS(0, S_CTRL); 338 else 339 goto bad; 340 return UNVIS_NOCHAR; 341 342 case S_META1: 343 *astate = SS(0, S_GROUND); 344 *cp |= c; 345 return UNVIS_VALID; 346 347 case S_CTRL: 348 if (c == '?') 349 *cp |= 0177; 350 else 351 *cp |= c & 037; 352 *astate = SS(0, S_GROUND); 353 return UNVIS_VALID; 354 355 case S_OCTAL2: /* second possible octal digit */ 356 if (isoctal(uc)) { 357 /* 358 * yes - and maybe a third 359 */ 360 *cp = (*cp << 3) + (c - '0'); 361 *astate = SS(0, S_OCTAL3); 362 return UNVIS_NOCHAR; 363 } 364 /* 365 * no - done with current sequence, push back passed char 366 */ 367 *astate = SS(0, S_GROUND); 368 return UNVIS_VALIDPUSH; 369 370 case S_OCTAL3: /* third possible octal digit */ 371 *astate = SS(0, S_GROUND); 372 if (isoctal(uc)) { 373 *cp = (*cp << 3) + (c - '0'); 374 return UNVIS_VALID; 375 } 376 /* 377 * we were done, push back passed char 378 */ 379 return UNVIS_VALIDPUSH; 380 381 case S_HEX: 382 if (!isxdigit(uc)) 383 goto bad; 384 /*FALLTHROUGH*/ 385 case S_HEX1: 386 if (isxdigit(uc)) { 387 *cp = xtod(uc); 388 *astate = SS(0, S_HEX2); 389 return UNVIS_NOCHAR; 390 } 391 /* 392 * no - done with current sequence, push back passed char 393 */ 394 *astate = SS(0, S_GROUND); 395 return UNVIS_VALIDPUSH; 396 397 case S_HEX2: 398 *astate = S_GROUND; 399 if (isxdigit(uc)) { 400 *cp = xtod(uc) | (*cp << 4); 401 return UNVIS_VALID; 402 } 403 return UNVIS_VALIDPUSH; 404 405 case S_MIME1: 406 if (uc == '\n' || uc == '\r') { 407 *astate = SS(0, S_EATCRNL); 408 return UNVIS_NOCHAR; 409 } 410 if (isxdigit(uc) && (isdigit(uc) || isupper(uc))) { 411 *cp = XTOD(uc); 412 *astate = SS(0, S_MIME2); 413 return UNVIS_NOCHAR; 414 } 415 goto bad; 416 417 case S_MIME2: 418 if (isxdigit(uc) && (isdigit(uc) || isupper(uc))) { 419 *astate = SS(0, S_GROUND); 420 *cp = XTOD(uc) | (*cp << 4); 421 return UNVIS_VALID; 422 } 423 goto bad; 424 425 case S_EATCRNL: 426 switch (uc) { 427 case '\r': 428 case '\n': 429 return UNVIS_NOCHAR; 430 case '=': 431 *astate = SS(0, S_MIME1); 432 return UNVIS_NOCHAR; 433 default: 434 *cp = uc; 435 *astate = SS(0, S_GROUND); 436 return UNVIS_VALID; 437 } 438 439 case S_AMP: 440 *cp = 0; 441 if (uc == '#') { 442 *astate = SS(0, S_NUMBER); 443 return UNVIS_NOCHAR; 444 } 445 *astate = SS(0, S_STRING); 446 /*FALLTHROUGH*/ 447 448 case S_STRING: 449 ia = *cp; /* index in the array */ 450 is = GI(*astate); /* index in the string */ 451 lc = is == 0 ? 0 : nv[ia].name[is - 1]; /* last character */ 452 453 if (uc == ';') 454 uc = '\0'; 455 456 for (; ia < __arraycount(nv); ia++) { 457 if (is != 0 && nv[ia].name[is - 1] != lc) 458 goto bad; 459 if (nv[ia].name[is] == uc) 460 break; 461 } 462 463 if (ia == __arraycount(nv)) 464 goto bad; 465 466 if (uc != 0) { 467 *cp = ia; 468 *astate = SS(is + 1, S_STRING); 469 return UNVIS_NOCHAR; 470 } 471 472 *cp = nv[ia].value; 473 *astate = SS(0, S_GROUND); 474 return UNVIS_VALID; 475 476 case S_NUMBER: 477 if (uc == ';') 478 return UNVIS_VALID; 479 if (!isdigit(uc)) 480 goto bad; 481 *cp += (*cp * 10) + uc - '0'; 482 return UNVIS_NOCHAR; 483 484 default: 485 bad: 486 /* 487 * decoder in unknown state - (probably uninitialized) 488 */ 489 *astate = SS(0, S_GROUND); 490 return UNVIS_SYNBAD; 491 } 492 } 493 494 /* 495 * strnunvisx - decode src into dst 496 * 497 * Number of chars decoded into dst is returned, -1 on error. 498 * Dst is null terminated. 499 */ 500 501 int 502 strnunvisx(char *dst, size_t dlen, const char *src, int flag) 503 { 504 char c; 505 char t = '\0', *start = dst; 506 int state = 0; 507 508 _DIAGASSERT(src != NULL); 509 _DIAGASSERT(dst != NULL); 510 #define CHECKSPACE() \ 511 do { \ 512 if (dlen-- == 0) { \ 513 errno = ENOSPC; \ 514 return -1; \ 515 } \ 516 } while (0) 517 518 while ((c = *src++) != '\0') { 519 again: 520 switch (unvis(&t, c, &state, flag)) { 521 case UNVIS_VALID: 522 CHECKSPACE(); 523 *dst++ = t; 524 break; 525 case UNVIS_VALIDPUSH: 526 CHECKSPACE(); 527 *dst++ = t; 528 goto again; 529 case 0: 530 case UNVIS_NOCHAR: 531 break; 532 case UNVIS_SYNBAD: 533 errno = EINVAL; 534 return -1; 535 default: 536 _DIAGASSERT(/*CONSTCOND*/0); 537 errno = EINVAL; 538 return -1; 539 } 540 } 541 if (unvis(&t, c, &state, UNVIS_END) == UNVIS_VALID) { 542 CHECKSPACE(); 543 *dst++ = t; 544 } 545 CHECKSPACE(); 546 *dst = '\0'; 547 return (int)(dst - start); 548 } 549 550 int 551 strunvisx(char *dst, const char *src, int flag) 552 { 553 return strnunvisx(dst, (size_t)~0, src, flag); 554 } 555 556 int 557 strunvis(char *dst, const char *src) 558 { 559 return strnunvisx(dst, (size_t)~0, src, 0); 560 } 561 562 int 563 strnunvis(char *dst, size_t dlen, const char *src) 564 { 565 return strnunvisx(dst, dlen, src, 0); 566 } 567 #endif 568