1 /* 2 * Copyright (c) Ian F. Darwin 1986-1995. 3 * Software written by Ian F. Darwin and others; 4 * maintained 1995-present by Christos Zoulas and others. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice immediately at the beginning of the file, without modification, 11 * 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 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR 20 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 /* 29 * ASCII magic -- file types that we know based on keywords 30 * that can appear anywhere in the file. 31 * 32 * Extensively modified by Eric Fischer <enf@pobox.com> in July, 2000, 33 * to handle character codes other than ASCII on a unified basis. 34 */ 35 36 #include "file.h" 37 38 #ifndef lint 39 FILE_RCSID("@(#)$File: ascmagic.c,v 1.75 2009/02/03 20:27:51 christos Exp $") 40 #endif /* lint */ 41 42 #include "magic.h" 43 #include <string.h> 44 #include <memory.h> 45 #include <ctype.h> 46 #include <stdlib.h> 47 #ifdef HAVE_UNISTD_H 48 #include <unistd.h> 49 #endif 50 #include "names.h" 51 52 #define MAXLINELEN 300 /* longest sane line length */ 53 #define ISSPC(x) ((x) == ' ' || (x) == '\t' || (x) == '\r' || (x) == '\n' \ 54 || (x) == 0x85 || (x) == '\f') 55 56 private int ascmatch(const unsigned char *, const unichar *, size_t); 57 private unsigned char *encode_utf8(unsigned char *, size_t, unichar *, size_t); 58 private size_t trim_nuls(const unsigned char *, size_t); 59 60 /* 61 * Undo the NUL-termination kindly provided by process() 62 * but leave at least one byte to look at 63 */ 64 private size_t 65 trim_nuls(const unsigned char *buf, size_t nbytes) 66 { 67 while (nbytes > 1 && buf[nbytes - 1] == '\0') 68 nbytes--; 69 70 return nbytes; 71 } 72 73 protected int 74 file_ascmagic(struct magic_set *ms, const unsigned char *buf, size_t nbytes) 75 { 76 unichar *ubuf = NULL; 77 size_t ulen; 78 int rv = 1; 79 80 const char *code = NULL; 81 const char *code_mime = NULL; 82 const char *type = NULL; 83 84 if (ms->flags & MAGIC_APPLE) 85 return 0; 86 87 nbytes = trim_nuls(buf, nbytes); 88 89 /* If file doesn't look like any sort of text, give up. */ 90 if (file_encoding(ms, buf, nbytes, &ubuf, &ulen, &code, &code_mime, 91 &type) == 0) { 92 rv = 0; 93 goto done; 94 } 95 96 rv = file_ascmagic_with_encoding(ms, buf, nbytes, ubuf, ulen, code, 97 type); 98 99 done: 100 if (ubuf) 101 free(ubuf); 102 103 return rv; 104 } 105 106 protected int 107 file_ascmagic_with_encoding(struct magic_set *ms, const unsigned char *buf, 108 size_t nbytes, unichar *ubuf, size_t ulen, const char *code, 109 const char *type) 110 { 111 unsigned char *utf8_buf = NULL, *utf8_end; 112 size_t mlen, i; 113 const struct names *p; 114 int rv = -1; 115 int mime = ms->flags & MAGIC_MIME; 116 117 const char *subtype = NULL; 118 const char *subtype_mime = NULL; 119 120 int has_escapes = 0; 121 int has_backspace = 0; 122 int seen_cr = 0; 123 124 int n_crlf = 0; 125 int n_lf = 0; 126 int n_cr = 0; 127 int n_nel = 0; 128 129 size_t last_line_end = (size_t)-1; 130 int has_long_lines = 0; 131 132 if (ms->flags & MAGIC_APPLE) 133 return 0; 134 135 nbytes = trim_nuls(buf, nbytes); 136 137 /* If we have fewer than 2 bytes, give up. */ 138 if (nbytes <= 1) { 139 rv = 0; 140 goto done; 141 } 142 143 /* Convert ubuf to UTF-8 and try text soft magic */ 144 /* malloc size is a conservative overestimate; could be 145 improved, or at least realloced after conversion. */ 146 mlen = ulen * 6; 147 if ((utf8_buf = CAST(unsigned char *, malloc(mlen))) == NULL) { 148 file_oomem(ms, mlen); 149 goto done; 150 } 151 if ((utf8_end = encode_utf8(utf8_buf, mlen, ubuf, ulen)) == NULL) 152 goto done; 153 if ((rv = file_softmagic(ms, utf8_buf, (size_t)(utf8_end - utf8_buf), 154 TEXTTEST)) != 0) 155 goto done; 156 else 157 rv = -1; 158 159 /* look for tokens from names.h - this is expensive! */ 160 if ((ms->flags & MAGIC_NO_CHECK_TOKENS) != 0) 161 goto subtype_identified; 162 163 i = 0; 164 while (i < ulen) { 165 size_t end; 166 167 /* skip past any leading space */ 168 while (i < ulen && ISSPC(ubuf[i])) 169 i++; 170 if (i >= ulen) 171 break; 172 173 /* find the next whitespace */ 174 for (end = i + 1; end < nbytes; end++) 175 if (ISSPC(ubuf[end])) 176 break; 177 178 /* compare the word thus isolated against the token list */ 179 for (p = names; p < names + NNAMES; p++) { 180 if (ascmatch((const unsigned char *)p->name, ubuf + i, 181 end - i)) { 182 subtype = types[p->type].human; 183 subtype_mime = types[p->type].mime; 184 goto subtype_identified; 185 } 186 } 187 188 i = end; 189 } 190 191 subtype_identified: 192 193 /* Now try to discover other details about the file. */ 194 for (i = 0; i < ulen; i++) { 195 if (ubuf[i] == '\n') { 196 if (seen_cr) 197 n_crlf++; 198 else 199 n_lf++; 200 last_line_end = i; 201 } else if (seen_cr) 202 n_cr++; 203 204 seen_cr = (ubuf[i] == '\r'); 205 if (seen_cr) 206 last_line_end = i; 207 208 if (ubuf[i] == 0x85) { /* X3.64/ECMA-43 "next line" character */ 209 n_nel++; 210 last_line_end = i; 211 } 212 213 /* If this line is _longer_ than MAXLINELEN, remember it. */ 214 if (i > last_line_end + MAXLINELEN) 215 has_long_lines = 1; 216 217 if (ubuf[i] == '\033') 218 has_escapes = 1; 219 if (ubuf[i] == '\b') 220 has_backspace = 1; 221 } 222 223 /* Beware, if the data has been truncated, the final CR could have 224 been followed by a LF. If we have HOWMANY bytes, it indicates 225 that the data might have been truncated, probably even before 226 this function was called. */ 227 if (seen_cr && nbytes < HOWMANY) 228 n_cr++; 229 230 if (strcmp(type, "binary") == 0) { 231 rv = 0; 232 goto done; 233 } 234 if (mime) { 235 if ((mime & MAGIC_MIME_TYPE) != 0) { 236 if (subtype_mime) { 237 if (file_printf(ms, "%s", subtype_mime) == -1) 238 goto done; 239 } else { 240 if (file_printf(ms, "text/plain") == -1) 241 goto done; 242 } 243 } 244 } else { 245 if (file_printf(ms, "%s", code) == -1) 246 goto done; 247 248 if (subtype) { 249 if (file_printf(ms, " %s", subtype) == -1) 250 goto done; 251 } 252 253 if (file_printf(ms, " %s", type) == -1) 254 goto done; 255 256 if (has_long_lines) 257 if (file_printf(ms, ", with very long lines") == -1) 258 goto done; 259 260 /* 261 * Only report line terminators if we find one other than LF, 262 * or if we find none at all. 263 */ 264 if ((n_crlf == 0 && n_cr == 0 && n_nel == 0 && n_lf == 0) || 265 (n_crlf != 0 || n_cr != 0 || n_nel != 0)) { 266 if (file_printf(ms, ", with") == -1) 267 goto done; 268 269 if (n_crlf == 0 && n_cr == 0 && n_nel == 0 && n_lf == 0) { 270 if (file_printf(ms, " no") == -1) 271 goto done; 272 } else { 273 if (n_crlf) { 274 if (file_printf(ms, " CRLF") == -1) 275 goto done; 276 if (n_cr || n_lf || n_nel) 277 if (file_printf(ms, ",") == -1) 278 goto done; 279 } 280 if (n_cr) { 281 if (file_printf(ms, " CR") == -1) 282 goto done; 283 if (n_lf || n_nel) 284 if (file_printf(ms, ",") == -1) 285 goto done; 286 } 287 if (n_lf) { 288 if (file_printf(ms, " LF") == -1) 289 goto done; 290 if (n_nel) 291 if (file_printf(ms, ",") == -1) 292 goto done; 293 } 294 if (n_nel) 295 if (file_printf(ms, " NEL") == -1) 296 goto done; 297 } 298 299 if (file_printf(ms, " line terminators") == -1) 300 goto done; 301 } 302 303 if (has_escapes) 304 if (file_printf(ms, ", with escape sequences") == -1) 305 goto done; 306 if (has_backspace) 307 if (file_printf(ms, ", with overstriking") == -1) 308 goto done; 309 } 310 rv = 1; 311 done: 312 if (utf8_buf) 313 free(utf8_buf); 314 315 return rv; 316 } 317 318 private int 319 ascmatch(const unsigned char *s, const unichar *us, size_t ulen) 320 { 321 size_t i; 322 323 for (i = 0; i < ulen; i++) { 324 if (s[i] != us[i]) 325 return 0; 326 } 327 328 if (s[i]) 329 return 0; 330 else 331 return 1; 332 } 333 334 /* 335 * Encode Unicode string as UTF-8, returning pointer to character 336 * after end of string, or NULL if an invalid character is found. 337 */ 338 private unsigned char * 339 encode_utf8(unsigned char *buf, size_t len, unichar *ubuf, size_t ulen) 340 { 341 size_t i; 342 unsigned char *end = buf + len; 343 344 for (i = 0; i < ulen; i++) { 345 if (ubuf[i] <= 0x7f) { 346 if (end - buf < 1) 347 return NULL; 348 *buf++ = (unsigned char)ubuf[i]; 349 } else if (ubuf[i] <= 0x7ff) { 350 if (end - buf < 2) 351 return NULL; 352 *buf++ = (unsigned char)((ubuf[i] >> 6) + 0xc0); 353 *buf++ = (unsigned char)((ubuf[i] & 0x3f) + 0x80); 354 } else if (ubuf[i] <= 0xffff) { 355 if (end - buf < 3) 356 return NULL; 357 *buf++ = (unsigned char)((ubuf[i] >> 12) + 0xe0); 358 *buf++ = (unsigned char)(((ubuf[i] >> 6) & 0x3f) + 0x80); 359 *buf++ = (unsigned char)((ubuf[i] & 0x3f) + 0x80); 360 } else if (ubuf[i] <= 0x1fffff) { 361 if (end - buf < 4) 362 return NULL; 363 *buf++ = (unsigned char)((ubuf[i] >> 18) + 0xf0); 364 *buf++ = (unsigned char)(((ubuf[i] >> 12) & 0x3f) + 0x80); 365 *buf++ = (unsigned char)(((ubuf[i] >> 6) & 0x3f) + 0x80); 366 *buf++ = (unsigned char)((ubuf[i] & 0x3f) + 0x80); 367 } else if (ubuf[i] <= 0x3ffffff) { 368 if (end - buf < 5) 369 return NULL; 370 *buf++ = (unsigned char)((ubuf[i] >> 24) + 0xf8); 371 *buf++ = (unsigned char)(((ubuf[i] >> 18) & 0x3f) + 0x80); 372 *buf++ = (unsigned char)(((ubuf[i] >> 12) & 0x3f) + 0x80); 373 *buf++ = (unsigned char)(((ubuf[i] >> 6) & 0x3f) + 0x80); 374 *buf++ = (unsigned char)((ubuf[i] & 0x3f) + 0x80); 375 } else if (ubuf[i] <= 0x7fffffff) { 376 if (end - buf < 6) 377 return NULL; 378 *buf++ = (unsigned char)((ubuf[i] >> 30) + 0xfc); 379 *buf++ = (unsigned char)(((ubuf[i] >> 24) & 0x3f) + 0x80); 380 *buf++ = (unsigned char)(((ubuf[i] >> 18) & 0x3f) + 0x80); 381 *buf++ = (unsigned char)(((ubuf[i] >> 12) & 0x3f) + 0x80); 382 *buf++ = (unsigned char)(((ubuf[i] >> 6) & 0x3f) + 0x80); 383 *buf++ = (unsigned char)((ubuf[i] & 0x3f) + 0x80); 384 } else /* Invalid character */ 385 return NULL; 386 } 387 388 return buf; 389 } 390