1 /* $NetBSD: ascmagic.c,v 1.1.1.1 2009/05/08 16:35:06 christos Exp $ */ 2 3 /* 4 * Copyright (c) Ian F. Darwin 1986-1995. 5 * Software written by Ian F. Darwin and others; 6 * maintained 1995-present by Christos Zoulas and others. 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 immediately at the beginning of the file, without modification, 13 * this list of conditions, and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR 22 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28 * SUCH DAMAGE. 29 */ 30 /* 31 * ASCII magic -- file types that we know based on keywords 32 * that can appear anywhere in the file. 33 * 34 * Extensively modified by Eric Fischer <enf@pobox.com> in July, 2000, 35 * to handle character codes other than ASCII on a unified basis. 36 */ 37 38 #include "file.h" 39 40 #ifndef lint 41 #if 0 42 FILE_RCSID("@(#)$File: ascmagic.c,v 1.75 2009/02/03 20:27:51 christos Exp $") 43 #else 44 __RCSID("$NetBSD: ascmagic.c,v 1.1.1.1 2009/05/08 16:35:06 christos Exp $"); 45 #endif 46 #endif /* lint */ 47 48 #include "magic.h" 49 #include <string.h> 50 #include <memory.h> 51 #include <ctype.h> 52 #include <stdlib.h> 53 #ifdef HAVE_UNISTD_H 54 #include <unistd.h> 55 #endif 56 #include "names.h" 57 58 #define MAXLINELEN 300 /* longest sane line length */ 59 #define ISSPC(x) ((x) == ' ' || (x) == '\t' || (x) == '\r' || (x) == '\n' \ 60 || (x) == 0x85 || (x) == '\f') 61 62 private int ascmatch(const unsigned char *, const unichar *, size_t); 63 private unsigned char *encode_utf8(unsigned char *, size_t, unichar *, size_t); 64 private size_t trim_nuls(const unsigned char *, size_t); 65 66 /* 67 * Undo the NUL-termination kindly provided by process() 68 * but leave at least one byte to look at 69 */ 70 private size_t 71 trim_nuls(const unsigned char *buf, size_t nbytes) 72 { 73 while (nbytes > 1 && buf[nbytes - 1] == '\0') 74 nbytes--; 75 76 return nbytes; 77 } 78 79 protected int 80 file_ascmagic(struct magic_set *ms, const unsigned char *buf, size_t nbytes) 81 { 82 unichar *ubuf = NULL; 83 size_t ulen; 84 int rv = 1; 85 86 const char *code = NULL; 87 const char *code_mime = NULL; 88 const char *type = NULL; 89 90 if (ms->flags & MAGIC_APPLE) 91 return 0; 92 93 nbytes = trim_nuls(buf, nbytes); 94 95 /* If file doesn't look like any sort of text, give up. */ 96 if (file_encoding(ms, buf, nbytes, &ubuf, &ulen, &code, &code_mime, 97 &type) == 0) { 98 rv = 0; 99 goto done; 100 } 101 102 rv = file_ascmagic_with_encoding(ms, buf, nbytes, ubuf, ulen, code, 103 type); 104 105 done: 106 if (ubuf) 107 free(ubuf); 108 109 return rv; 110 } 111 112 protected int 113 file_ascmagic_with_encoding(struct magic_set *ms, const unsigned char *buf, 114 size_t nbytes, unichar *ubuf, size_t ulen, const char *code, 115 const char *type) 116 { 117 unsigned char *utf8_buf = NULL, *utf8_end; 118 size_t mlen, i; 119 const struct names *p; 120 int rv = -1; 121 int mime = ms->flags & MAGIC_MIME; 122 123 const char *subtype = NULL; 124 const char *subtype_mime = NULL; 125 126 int has_escapes = 0; 127 int has_backspace = 0; 128 int seen_cr = 0; 129 130 int n_crlf = 0; 131 int n_lf = 0; 132 int n_cr = 0; 133 int n_nel = 0; 134 135 size_t last_line_end = (size_t)-1; 136 int has_long_lines = 0; 137 138 if (ms->flags & MAGIC_APPLE) 139 return 0; 140 141 nbytes = trim_nuls(buf, nbytes); 142 143 /* If we have fewer than 2 bytes, give up. */ 144 if (nbytes <= 1) { 145 rv = 0; 146 goto done; 147 } 148 149 /* Convert ubuf to UTF-8 and try text soft magic */ 150 /* malloc size is a conservative overestimate; could be 151 improved, or at least realloced after conversion. */ 152 mlen = ulen * 6; 153 if ((utf8_buf = CAST(unsigned char *, malloc(mlen))) == NULL) { 154 file_oomem(ms, mlen); 155 goto done; 156 } 157 if ((utf8_end = encode_utf8(utf8_buf, mlen, ubuf, ulen)) == NULL) 158 goto done; 159 if ((rv = file_softmagic(ms, utf8_buf, (size_t)(utf8_end - utf8_buf), 160 TEXTTEST)) != 0) 161 goto done; 162 else 163 rv = -1; 164 165 /* look for tokens from names.h - this is expensive! */ 166 if ((ms->flags & MAGIC_NO_CHECK_TOKENS) != 0) 167 goto subtype_identified; 168 169 i = 0; 170 while (i < ulen) { 171 size_t end; 172 173 /* skip past any leading space */ 174 while (i < ulen && ISSPC(ubuf[i])) 175 i++; 176 if (i >= ulen) 177 break; 178 179 /* find the next whitespace */ 180 for (end = i + 1; end < nbytes; end++) 181 if (ISSPC(ubuf[end])) 182 break; 183 184 /* compare the word thus isolated against the token list */ 185 for (p = names; p < names + NNAMES; p++) { 186 if (ascmatch((const unsigned char *)p->name, ubuf + i, 187 end - i)) { 188 subtype = types[p->type].human; 189 subtype_mime = types[p->type].mime; 190 goto subtype_identified; 191 } 192 } 193 194 i = end; 195 } 196 197 subtype_identified: 198 199 /* Now try to discover other details about the file. */ 200 for (i = 0; i < ulen; i++) { 201 if (ubuf[i] == '\n') { 202 if (seen_cr) 203 n_crlf++; 204 else 205 n_lf++; 206 last_line_end = i; 207 } else if (seen_cr) 208 n_cr++; 209 210 seen_cr = (ubuf[i] == '\r'); 211 if (seen_cr) 212 last_line_end = i; 213 214 if (ubuf[i] == 0x85) { /* X3.64/ECMA-43 "next line" character */ 215 n_nel++; 216 last_line_end = i; 217 } 218 219 /* If this line is _longer_ than MAXLINELEN, remember it. */ 220 if (i > last_line_end + MAXLINELEN) 221 has_long_lines = 1; 222 223 if (ubuf[i] == '\033') 224 has_escapes = 1; 225 if (ubuf[i] == '\b') 226 has_backspace = 1; 227 } 228 229 /* Beware, if the data has been truncated, the final CR could have 230 been followed by a LF. If we have HOWMANY bytes, it indicates 231 that the data might have been truncated, probably even before 232 this function was called. */ 233 if (seen_cr && nbytes < HOWMANY) 234 n_cr++; 235 236 if (strcmp(type, "binary") == 0) { 237 rv = 0; 238 goto done; 239 } 240 if (mime) { 241 if ((mime & MAGIC_MIME_TYPE) != 0) { 242 if (subtype_mime) { 243 if (file_printf(ms, "%s", subtype_mime) == -1) 244 goto done; 245 } else { 246 if (file_printf(ms, "text/plain") == -1) 247 goto done; 248 } 249 } 250 } else { 251 if (file_printf(ms, "%s", code) == -1) 252 goto done; 253 254 if (subtype) { 255 if (file_printf(ms, " %s", subtype) == -1) 256 goto done; 257 } 258 259 if (file_printf(ms, " %s", type) == -1) 260 goto done; 261 262 if (has_long_lines) 263 if (file_printf(ms, ", with very long lines") == -1) 264 goto done; 265 266 /* 267 * Only report line terminators if we find one other than LF, 268 * or if we find none at all. 269 */ 270 if ((n_crlf == 0 && n_cr == 0 && n_nel == 0 && n_lf == 0) || 271 (n_crlf != 0 || n_cr != 0 || n_nel != 0)) { 272 if (file_printf(ms, ", with") == -1) 273 goto done; 274 275 if (n_crlf == 0 && n_cr == 0 && n_nel == 0 && n_lf == 0) { 276 if (file_printf(ms, " no") == -1) 277 goto done; 278 } else { 279 if (n_crlf) { 280 if (file_printf(ms, " CRLF") == -1) 281 goto done; 282 if (n_cr || n_lf || n_nel) 283 if (file_printf(ms, ",") == -1) 284 goto done; 285 } 286 if (n_cr) { 287 if (file_printf(ms, " CR") == -1) 288 goto done; 289 if (n_lf || n_nel) 290 if (file_printf(ms, ",") == -1) 291 goto done; 292 } 293 if (n_lf) { 294 if (file_printf(ms, " LF") == -1) 295 goto done; 296 if (n_nel) 297 if (file_printf(ms, ",") == -1) 298 goto done; 299 } 300 if (n_nel) 301 if (file_printf(ms, " NEL") == -1) 302 goto done; 303 } 304 305 if (file_printf(ms, " line terminators") == -1) 306 goto done; 307 } 308 309 if (has_escapes) 310 if (file_printf(ms, ", with escape sequences") == -1) 311 goto done; 312 if (has_backspace) 313 if (file_printf(ms, ", with overstriking") == -1) 314 goto done; 315 } 316 rv = 1; 317 done: 318 if (utf8_buf) 319 free(utf8_buf); 320 321 return rv; 322 } 323 324 private int 325 ascmatch(const unsigned char *s, const unichar *us, size_t ulen) 326 { 327 size_t i; 328 329 for (i = 0; i < ulen; i++) { 330 if (s[i] != us[i]) 331 return 0; 332 } 333 334 if (s[i]) 335 return 0; 336 else 337 return 1; 338 } 339 340 /* 341 * Encode Unicode string as UTF-8, returning pointer to character 342 * after end of string, or NULL if an invalid character is found. 343 */ 344 private unsigned char * 345 encode_utf8(unsigned char *buf, size_t len, unichar *ubuf, size_t ulen) 346 { 347 size_t i; 348 unsigned char *end = buf + len; 349 350 for (i = 0; i < ulen; i++) { 351 if (ubuf[i] <= 0x7f) { 352 if (end - buf < 1) 353 return NULL; 354 *buf++ = (unsigned char)ubuf[i]; 355 } else if (ubuf[i] <= 0x7ff) { 356 if (end - buf < 2) 357 return NULL; 358 *buf++ = (unsigned char)((ubuf[i] >> 6) + 0xc0); 359 *buf++ = (unsigned char)((ubuf[i] & 0x3f) + 0x80); 360 } else if (ubuf[i] <= 0xffff) { 361 if (end - buf < 3) 362 return NULL; 363 *buf++ = (unsigned char)((ubuf[i] >> 12) + 0xe0); 364 *buf++ = (unsigned char)(((ubuf[i] >> 6) & 0x3f) + 0x80); 365 *buf++ = (unsigned char)((ubuf[i] & 0x3f) + 0x80); 366 } else if (ubuf[i] <= 0x1fffff) { 367 if (end - buf < 4) 368 return NULL; 369 *buf++ = (unsigned char)((ubuf[i] >> 18) + 0xf0); 370 *buf++ = (unsigned char)(((ubuf[i] >> 12) & 0x3f) + 0x80); 371 *buf++ = (unsigned char)(((ubuf[i] >> 6) & 0x3f) + 0x80); 372 *buf++ = (unsigned char)((ubuf[i] & 0x3f) + 0x80); 373 } else if (ubuf[i] <= 0x3ffffff) { 374 if (end - buf < 5) 375 return NULL; 376 *buf++ = (unsigned char)((ubuf[i] >> 24) + 0xf8); 377 *buf++ = (unsigned char)(((ubuf[i] >> 18) & 0x3f) + 0x80); 378 *buf++ = (unsigned char)(((ubuf[i] >> 12) & 0x3f) + 0x80); 379 *buf++ = (unsigned char)(((ubuf[i] >> 6) & 0x3f) + 0x80); 380 *buf++ = (unsigned char)((ubuf[i] & 0x3f) + 0x80); 381 } else if (ubuf[i] <= 0x7fffffff) { 382 if (end - buf < 6) 383 return NULL; 384 *buf++ = (unsigned char)((ubuf[i] >> 30) + 0xfc); 385 *buf++ = (unsigned char)(((ubuf[i] >> 24) & 0x3f) + 0x80); 386 *buf++ = (unsigned char)(((ubuf[i] >> 18) & 0x3f) + 0x80); 387 *buf++ = (unsigned char)(((ubuf[i] >> 12) & 0x3f) + 0x80); 388 *buf++ = (unsigned char)(((ubuf[i] >> 6) & 0x3f) + 0x80); 389 *buf++ = (unsigned char)((ubuf[i] & 0x3f) + 0x80); 390 } else /* Invalid character */ 391 return NULL; 392 } 393 394 return buf; 395 } 396