1 /* $NetBSD: ascmagic.c,v 1.1.1.16 2023/08/18 18:36:49 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 -- try to detect text encoding. 32 * 33 * Extensively modified by Eric Fischer <enf (at) pobox.com> in July, 2000, 34 * to handle character codes other than ASCII on a unified basis. 35 */ 36 37 #include "file.h" 38 39 #ifndef lint 40 #if 0 41 FILE_RCSID("@(#)$File: ascmagic.c,v 1.116 2023/05/21 16:08:50 christos Exp $") 42 #else 43 __RCSID("$NetBSD: ascmagic.c,v 1.1.1.16 2023/08/18 18:36:49 christos Exp $"); 44 #endif 45 #endif /* lint */ 46 47 #include "magic.h" 48 #include <string.h> 49 #include <ctype.h> 50 #include <stdlib.h> 51 #ifdef HAVE_UNISTD_H 52 #include <unistd.h> 53 #endif 54 55 #define MAXLINELEN 300 /* longest sane line length */ 56 #define ISSPC(x) ((x) == ' ' || (x) == '\t' || (x) == '\r' || (x) == '\n' \ 57 || (x) == 0x85 || (x) == '\f') 58 59 file_private unsigned char *encode_utf8(unsigned char *, size_t, file_unichar_t *, 60 size_t); 61 file_private size_t trim_nuls(const unsigned char *, size_t); 62 63 /* 64 * Undo the NUL-termination kindly provided by process() 65 * but leave at least one byte to look at 66 */ 67 file_private size_t 68 trim_nuls(const unsigned char *buf, size_t nbytes) 69 { 70 while (nbytes > 1 && buf[nbytes - 1] == '\0') 71 nbytes--; 72 73 return nbytes; 74 } 75 76 file_protected int 77 file_ascmagic(struct magic_set *ms, const struct buffer *b, int text) 78 { 79 file_unichar_t *ubuf = NULL; 80 size_t ulen = 0; 81 int rv = 1; 82 struct buffer bb; 83 84 const char *code = NULL; 85 const char *code_mime = NULL; 86 const char *type = NULL; 87 88 bb = *b; 89 bb.flen = trim_nuls(CAST(const unsigned char *, b->fbuf), b->flen); 90 /* 91 * Avoid trimming at an odd byte if the original buffer was evenly 92 * sized; this avoids losing the last character on UTF-16 LE text 93 */ 94 if ((bb.flen & 1) && !(b->flen & 1)) 95 bb.flen++; 96 97 /* If file doesn't look like any sort of text, give up. */ 98 if (file_encoding(ms, &bb, &ubuf, &ulen, &code, &code_mime, 99 &type) == 0) 100 rv = 0; 101 else 102 rv = file_ascmagic_with_encoding(ms, &bb, 103 ubuf, ulen, code, type, text); 104 105 free(ubuf); 106 107 return rv; 108 } 109 110 file_protected int 111 file_ascmagic_with_encoding(struct magic_set *ms, const struct buffer *b, 112 file_unichar_t *ubuf, size_t ulen, const char *code, const char *type, 113 int text) 114 { 115 struct buffer bb; 116 const unsigned char *buf = CAST(const unsigned char *, b->fbuf); 117 size_t nbytes = b->flen; 118 unsigned char *utf8_buf = NULL, *utf8_end; 119 size_t mlen, i, len; 120 int rv = -1; 121 int mime = ms->flags & MAGIC_MIME; 122 int need_separator = 0; 123 124 const char *subtype = NULL; 125 126 int has_escapes = 0; 127 int has_backspace = 0; 128 int seen_cr = 0; 129 130 size_t n_crlf = 0; 131 size_t n_lf = 0; 132 size_t n_cr = 0; 133 size_t n_nel = 0; 134 int executable = 0; 135 136 size_t last_line_end = CAST(size_t, -1); 137 size_t has_long_lines = 0; 138 139 nbytes = trim_nuls(buf, nbytes); 140 141 /* If we have fewer than 2 bytes, give up. */ 142 if (nbytes <= 1) { 143 rv = 0; 144 goto done; 145 } 146 147 if (ulen > 0 && (ms->flags & MAGIC_NO_CHECK_SOFT) == 0) { 148 /* Convert ubuf to UTF-8 and try text soft magic */ 149 /* malloc size is a conservative overestimate; could be 150 improved, or at least realloced after conversion. */ 151 mlen = ulen * 6; 152 if ((utf8_buf = CAST(unsigned char *, malloc(mlen))) == NULL) { 153 file_oomem(ms, mlen); 154 goto done; 155 } 156 if ((utf8_end = encode_utf8(utf8_buf, mlen, ubuf, ulen)) 157 == NULL) { 158 rv = 0; 159 goto done; 160 } 161 buffer_init(&bb, b->fd, &b->st, utf8_buf, 162 CAST(size_t, utf8_end - utf8_buf)); 163 164 if ((rv = file_softmagic(ms, &bb, NULL, NULL, 165 TEXTTEST, text)) == 0) 166 rv = -1; 167 else 168 need_separator = 1; 169 buffer_fini(&bb); 170 if ((ms->flags & (MAGIC_APPLE|MAGIC_EXTENSION))) { 171 rv = rv == -1 ? 0 : 1; 172 goto done; 173 } 174 } 175 176 if ((ms->flags & (MAGIC_APPLE|MAGIC_EXTENSION))) { 177 rv = 0; 178 goto done; 179 } 180 181 /* Now try to discover other details about the file. */ 182 for (i = 0; i < ulen; i++) { 183 if (ubuf[i] == '\n') { 184 if (seen_cr) 185 n_crlf++; 186 else 187 n_lf++; 188 last_line_end = i; 189 } else if (seen_cr) 190 n_cr++; 191 192 seen_cr = (ubuf[i] == '\r'); 193 if (seen_cr) 194 last_line_end = i; 195 196 if (ubuf[i] == 0x85) { /* X3.64/ECMA-43 "next line" character */ 197 n_nel++; 198 last_line_end = i; 199 } 200 201 /* If this line is _longer_ than MAXLINELEN, remember it. */ 202 if (i > last_line_end + MAXLINELEN) { 203 size_t ll = i - last_line_end; 204 if (ll > has_long_lines) 205 has_long_lines = ll; 206 } 207 208 if (ubuf[i] == '\033') 209 has_escapes = 1; 210 if (ubuf[i] == '\b') 211 has_backspace = 1; 212 } 213 214 if (strcmp(type, "binary") == 0) { 215 rv = 0; 216 goto done; 217 } 218 len = file_printedlen(ms); 219 if (mime) { 220 if ((mime & MAGIC_MIME_TYPE) != 0) { 221 if (len) { 222 /* 223 * Softmagic printed something, we 224 * are either done, or we need a separator 225 */ 226 if ((ms->flags & MAGIC_CONTINUE) == 0) { 227 rv = 1; 228 goto done; 229 } 230 if (need_separator && file_separator(ms) == -1) 231 goto done; 232 } 233 if (file_printf(ms, "text/plain") == -1) 234 goto done; 235 } 236 } else { 237 if (len) { 238 switch (file_replace(ms, " text$", ", ")) { 239 case 0: 240 switch (file_replace(ms, " text executable$", 241 ", ")) { 242 case 0: 243 if (file_printf(ms, ", ") == -1) 244 goto done; 245 break; 246 case -1: 247 goto done; 248 default: 249 executable = 1; 250 break; 251 } 252 break; 253 case -1: 254 goto done; 255 default: 256 break; 257 } 258 } 259 260 if (file_printf(ms, "%s", code) == -1) 261 goto done; 262 263 if (subtype) { 264 if (file_printf(ms, " %s", subtype) == -1) 265 goto done; 266 } 267 268 if (file_printf(ms, " %s", type) == -1) 269 goto done; 270 271 if (executable) 272 if (file_printf(ms, " executable") == -1) 273 goto done; 274 275 if (has_long_lines) 276 if (file_printf(ms, ", with very long lines (%" 277 SIZE_T_FORMAT "u)", has_long_lines) == -1) 278 goto done; 279 280 /* 281 * Only report line terminators if we find one other than LF, 282 * or if we find none at all. 283 */ 284 if ((n_crlf == 0 && n_cr == 0 && n_nel == 0 && n_lf == 0) || 285 (n_crlf != 0 || n_cr != 0 || n_nel != 0)) { 286 if (file_printf(ms, ", with") == -1) 287 goto done; 288 289 if (n_crlf == 0 && n_cr == 0 && 290 n_nel == 0 && n_lf == 0) { 291 if (file_printf(ms, " no") == -1) 292 goto done; 293 } else { 294 if (n_crlf) { 295 if (file_printf(ms, " CRLF") == -1) 296 goto done; 297 if (n_cr || n_lf || n_nel) 298 if (file_printf(ms, ",") == -1) 299 goto done; 300 } 301 if (n_cr) { 302 if (file_printf(ms, " CR") == -1) 303 goto done; 304 if (n_lf || n_nel) 305 if (file_printf(ms, ",") == -1) 306 goto done; 307 } 308 if (n_lf) { 309 if (file_printf(ms, " LF") == -1) 310 goto done; 311 if (n_nel) 312 if (file_printf(ms, ",") == -1) 313 goto done; 314 } 315 if (n_nel) 316 if (file_printf(ms, " NEL") == -1) 317 goto done; 318 } 319 320 if (file_printf(ms, " line terminators") == -1) 321 goto done; 322 } 323 324 if (has_escapes) 325 if (file_printf(ms, ", with escape sequences") == -1) 326 goto done; 327 if (has_backspace) 328 if (file_printf(ms, ", with overstriking") == -1) 329 goto done; 330 } 331 rv = 1; 332 done: 333 free(utf8_buf); 334 335 return rv; 336 } 337 338 /* 339 * Encode Unicode string as UTF-8, returning pointer to character 340 * after end of string, or NULL if an invalid character is found. 341 */ 342 file_private unsigned char * 343 encode_utf8(unsigned char *buf, size_t len, file_unichar_t *ubuf, size_t ulen) 344 { 345 size_t i; 346 unsigned char *end = buf + len; 347 348 for (i = 0; i < ulen; i++) { 349 if (ubuf[i] <= 0x7f) { 350 if (end - buf < 1) 351 return NULL; 352 *buf++ = CAST(unsigned char, ubuf[i]); 353 continue; 354 } 355 if (ubuf[i] <= 0x7ff) { 356 if (end - buf < 2) 357 return NULL; 358 *buf++ = CAST(unsigned char, (ubuf[i] >> 6) + 0xc0); 359 goto out1; 360 } 361 if (ubuf[i] <= 0xffff) { 362 if (end - buf < 3) 363 return NULL; 364 *buf++ = CAST(unsigned char, (ubuf[i] >> 12) + 0xe0); 365 goto out2; 366 } 367 if (ubuf[i] <= 0x1fffff) { 368 if (end - buf < 4) 369 return NULL; 370 *buf++ = CAST(unsigned char, (ubuf[i] >> 18) + 0xf0); 371 goto out3; 372 } 373 if (ubuf[i] <= 0x3ffffff) { 374 if (end - buf < 5) 375 return NULL; 376 *buf++ = CAST(unsigned char, (ubuf[i] >> 24) + 0xf8); 377 goto out4; 378 } 379 if (ubuf[i] <= 0x7fffffff) { 380 if (end - buf < 6) 381 return NULL; 382 *buf++ = CAST(unsigned char, (ubuf[i] >> 30) + 0xfc); 383 goto out5; 384 } 385 /* Invalid character */ 386 return NULL; 387 out5: *buf++ = CAST(unsigned char, ((ubuf[i] >> 24) & 0x3f) + 0x80); 388 out4: *buf++ = CAST(unsigned char, ((ubuf[i] >> 18) & 0x3f) + 0x80); 389 out3: *buf++ = CAST(unsigned char, ((ubuf[i] >> 12) & 0x3f) + 0x80); 390 out2: *buf++ = CAST(unsigned char, ((ubuf[i] >> 6) & 0x3f) + 0x80); 391 out1: *buf++ = CAST(unsigned char, ((ubuf[i] >> 0) & 0x3f) + 0x80); 392 } 393 394 return buf; 395 } 396
Indexes created Tue Feb 24 01:34:59 UTC 2026