1 /* 2 * Copyright (c) Christos Zoulas 2003. 3 * All Rights Reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice immediately at the beginning of the file, without modification, 10 * this list of conditions, and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR 19 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25 * SUCH DAMAGE. 26 */ 27 28 #ifdef WIN32 29 #include <windows.h> 30 #include <shlwapi.h> 31 #endif 32 33 #include "file.h" 34 35 #ifndef lint 36 FILE_RCSID("@(#)$File: magic.c,v 1.72 2011/03/20 20:36:52 christos Exp $") 37 #endif /* lint */ 38 39 #include "magic.h" 40 41 #include <stdlib.h> 42 #include <unistd.h> 43 #include <string.h> 44 #ifdef QUICK 45 #include <sys/mman.h> 46 #endif 47 #ifdef HAVE_LIMITS_H 48 #include <limits.h> /* for PIPE_BUF */ 49 #endif 50 51 #if defined(HAVE_UTIMES) 52 # include <sys/time.h> 53 #elif defined(HAVE_UTIME) 54 # if defined(HAVE_SYS_UTIME_H) 55 # include <sys/utime.h> 56 # elif defined(HAVE_UTIME_H) 57 # include <utime.h> 58 # endif 59 #endif 60 61 #ifdef HAVE_UNISTD_H 62 #include <unistd.h> /* for read() */ 63 #endif 64 65 #include "patchlevel.h" 66 67 #ifndef PIPE_BUF 68 /* Get the PIPE_BUF from pathconf */ 69 #ifdef _PC_PIPE_BUF 70 #define PIPE_BUF pathconf(".", _PC_PIPE_BUF) 71 #else 72 #define PIPE_BUF 512 73 #endif 74 #endif 75 76 private void free_mlist(struct mlist *); 77 private void close_and_restore(const struct magic_set *, const char *, int, 78 const struct stat *); 79 private int unreadable_info(struct magic_set *, mode_t, const char *); 80 private const char* get_default_magic(void); 81 #ifndef COMPILE_ONLY 82 private const char *file_or_fd(struct magic_set *, const char *, int); 83 #endif 84 85 #ifndef STDIN_FILENO 86 #define STDIN_FILENO 0 87 #endif 88 89 #ifdef WIN32 90 BOOL WINAPI DllMain(HINSTANCE hinstDLL, 91 DWORD fdwReason __attribute__((__unused__)), 92 LPVOID lpvReserved __attribute__((__unused__))); 93 94 CHAR dllpath[MAX_PATH + 1] = { 0 }; 95 96 BOOL WINAPI DllMain(HINSTANCE hinstDLL, 97 DWORD fdwReason __attribute__((__unused__)), 98 LPVOID lpvReserved __attribute__((__unused__))) 99 { 100 if (dllpath[0] == 0 && 101 GetModuleFileNameA(hinstDLL, dllpath, MAX_PATH) != 0) 102 PathRemoveFileSpecA(dllpath); 103 return TRUE; 104 } 105 #endif 106 107 private const char * 108 get_default_magic(void) 109 { 110 static const char hmagic[] = "/.magic/magic.mgc"; 111 static char *default_magic; 112 char *home, *hmagicpath; 113 114 #ifndef WIN32 115 struct stat st; 116 117 if (default_magic) { 118 free(default_magic); 119 default_magic = NULL; 120 } 121 if ((home = getenv("HOME")) == NULL) 122 return MAGIC; 123 124 if (asprintf(&hmagicpath, "%s/.magic", home) < 0) 125 return MAGIC; 126 if (stat(hmagicpath, &st) == -1) 127 goto out; 128 if (S_ISDIR(st.st_mode)) { 129 free(hmagicpath); 130 if (asprintf(&hmagicpath, "%s/%s", home, hmagic) < 0) 131 return MAGIC; 132 if (access(hmagicpath, R_OK) == -1) 133 goto out; 134 } 135 136 if (asprintf(&default_magic, "%s:%s", hmagicpath, MAGIC) < 0) 137 goto out; 138 free(hmagicpath); 139 return default_magic; 140 out: 141 default_magic = NULL; 142 free(hmagicpath); 143 return MAGIC; 144 #else 145 char *hmagicp = hmagicpath; 146 char *tmppath = NULL; 147 148 #define APPENDPATH() \ 149 do { \ 150 if (tmppath && access(tmppath, R_OK) != -1) { \ 151 if (hmagicpath == NULL) { \ 152 hmagicpath = tmppath; \ 153 tmppath = NULL; \ 154 } else { \ 155 free(tmppath); \ 156 if (asprintf(&hmagicp, "%s%c%s", hmagicpath, \ 157 PATHSEP, tmppath) >= 0) { \ 158 free(hmagicpath); \ 159 hmagicpath = hmagicp; \ 160 } \ 161 } \ 162 } while (/*CONSTCOND*/0) 163 164 if (default_magic) { 165 free(default_magic); 166 default_magic = NULL; 167 } 168 169 /* First, try to get user-specific magic file */ 170 if ((home = getenv("LOCALAPPDATA")) == NULL) { 171 if ((home = getenv("USERPROFILE")) != NULL) 172 if (asprintf(&tmppath, 173 "%s/Local Settings/Application Data%s", home, 174 hmagic) < 0) 175 tmppath = NULL; 176 } else { 177 if (asprintf(&tmppath, "%s%s", home, hmagic) < 0) 178 tmppath = NULL; 179 } 180 181 APPENDPATH(); 182 183 /* Second, try to get a magic file from Common Files */ 184 if ((home = getenv("COMMONPROGRAMFILES")) != NULL) { 185 if (asprintf(&tmppath, "%s%s", home, hmagic) >= 0) 186 APPENDPATH(); 187 } 188 189 190 /* Third, try to get magic file relative to dll location */ 191 if (dllpath[0] != 0) { 192 if (strlen(dllpath) > 3 && 193 stricmp(&dllpath[strlen(dllpath) - 3], "bin") == 0) { 194 if (asprintf(&tmppath, 195 "%s/../share/misc/magic.mgc", dllpath) >= 0) 196 APPENDPATH(); 197 } else { 198 if (asprintf(&tmppath, 199 "%s/share/misc/magic.mgc", dllpath) >= 0) 200 APPENDPATH(); 201 else if (asprintf(&tmppath, 202 "%s/magic.mgc", dllpath) >= 0) 203 APPENDPATH(); 204 } 205 } 206 207 /* Don't put MAGIC constant - it likely points to a file within MSys 208 tree */ 209 default_magic = hmagicpath; 210 return default_magic; 211 #endif 212 } 213 214 public const char * 215 magic_getpath(const char *magicfile, int action) 216 { 217 if (magicfile != NULL) 218 return magicfile; 219 220 magicfile = getenv("MAGIC"); 221 if (magicfile != NULL) 222 return magicfile; 223 224 return action == FILE_LOAD ? get_default_magic() : MAGIC; 225 } 226 227 public struct magic_set * 228 magic_open(int flags) 229 { 230 struct magic_set *ms; 231 size_t len; 232 233 if ((ms = CAST(struct magic_set *, calloc((size_t)1, 234 sizeof(struct magic_set)))) == NULL) 235 return NULL; 236 237 if (magic_setflags(ms, flags) == -1) { 238 errno = EINVAL; 239 goto free; 240 } 241 242 ms->o.buf = ms->o.pbuf = NULL; 243 len = (ms->c.len = 10) * sizeof(*ms->c.li); 244 245 if ((ms->c.li = CAST(struct level_info *, malloc(len))) == NULL) 246 goto free; 247 248 ms->event_flags = 0; 249 ms->error = -1; 250 ms->mlist = NULL; 251 ms->file = "unknown"; 252 ms->line = 0; 253 return ms; 254 free: 255 free(ms); 256 return NULL; 257 } 258 259 private void 260 free_mlist(struct mlist *mlist) 261 { 262 struct mlist *ml; 263 264 if (mlist == NULL) 265 return; 266 267 for (ml = mlist->next; ml != mlist;) { 268 struct mlist *next = ml->next; 269 struct magic *mg = ml->magic; 270 file_delmagic(mg, ml->mapped, ml->nmagic); 271 free(ml); 272 ml = next; 273 } 274 free(ml); 275 } 276 277 private int 278 unreadable_info(struct magic_set *ms, mode_t md, const char *file) 279 { 280 /* We cannot open it, but we were able to stat it. */ 281 if (access(file, W_OK) == 0) 282 if (file_printf(ms, "writable, ") == -1) 283 return -1; 284 if (access(file, X_OK) == 0) 285 if (file_printf(ms, "executable, ") == -1) 286 return -1; 287 if (S_ISREG(md)) 288 if (file_printf(ms, "regular file, ") == -1) 289 return -1; 290 if (file_printf(ms, "no read permission") == -1) 291 return -1; 292 return 0; 293 } 294 295 public void 296 magic_close(struct magic_set *ms) 297 { 298 free_mlist(ms->mlist); 299 free(ms->o.pbuf); 300 free(ms->o.buf); 301 free(ms->c.li); 302 free(ms); 303 } 304 305 /* 306 * load a magic file 307 */ 308 public int 309 magic_load(struct magic_set *ms, const char *magicfile) 310 { 311 struct mlist *ml = file_apprentice(ms, magicfile, FILE_LOAD); 312 if (ml) { 313 free_mlist(ms->mlist); 314 ms->mlist = ml; 315 return 0; 316 } 317 return -1; 318 } 319 320 public int 321 magic_compile(struct magic_set *ms, const char *magicfile) 322 { 323 struct mlist *ml = file_apprentice(ms, magicfile, FILE_COMPILE); 324 free_mlist(ml); 325 return ml ? 0 : -1; 326 } 327 328 public int 329 magic_check(struct magic_set *ms, const char *magicfile) 330 { 331 struct mlist *ml = file_apprentice(ms, magicfile, FILE_CHECK); 332 free_mlist(ml); 333 return ml ? 0 : -1; 334 } 335 336 public int 337 magic_list(struct magic_set *ms, const char *magicfile) 338 { 339 struct mlist *ml = file_apprentice(ms, magicfile, FILE_LIST); 340 free_mlist(ml); 341 return ml ? 0 : -1; 342 } 343 344 private void 345 close_and_restore(const struct magic_set *ms, const char *name, int fd, 346 const struct stat *sb) 347 { 348 if (fd == STDIN_FILENO) 349 return; 350 (void) close(fd); 351 352 if ((ms->flags & MAGIC_PRESERVE_ATIME) != 0) { 353 /* 354 * Try to restore access, modification times if read it. 355 * This is really *bad* because it will modify the status 356 * time of the file... And of course this will affect 357 * backup programs 358 */ 359 #ifdef HAVE_UTIMES 360 struct timeval utsbuf[2]; 361 (void)memset(utsbuf, 0, sizeof(utsbuf)); 362 utsbuf[0].tv_sec = sb->st_atime; 363 utsbuf[1].tv_sec = sb->st_mtime; 364 365 (void) utimes(name, utsbuf); /* don't care if loses */ 366 #elif defined(HAVE_UTIME_H) || defined(HAVE_SYS_UTIME_H) 367 struct utimbuf utbuf; 368 369 (void)memset(&utbuf, 0, sizeof(utbuf)); 370 utbuf.actime = sb->st_atime; 371 utbuf.modtime = sb->st_mtime; 372 (void) utime(name, &utbuf); /* don't care if loses */ 373 #endif 374 } 375 } 376 377 #ifndef COMPILE_ONLY 378 379 /* 380 * find type of descriptor 381 */ 382 public const char * 383 magic_descriptor(struct magic_set *ms, int fd) 384 { 385 return file_or_fd(ms, NULL, fd); 386 } 387 388 /* 389 * find type of named file 390 */ 391 public const char * 392 magic_file(struct magic_set *ms, const char *inname) 393 { 394 return file_or_fd(ms, inname, STDIN_FILENO); 395 } 396 397 private const char * 398 file_or_fd(struct magic_set *ms, const char *inname, int fd) 399 { 400 int rv = -1; 401 unsigned char *buf; 402 struct stat sb; 403 ssize_t nbytes = 0; /* number of bytes read from a datafile */ 404 int ispipe = 0; 405 406 /* 407 * one extra for terminating '\0', and 408 * some overlapping space for matches near EOF 409 */ 410 #define SLOP (1 + sizeof(union VALUETYPE)) 411 if ((buf = CAST(unsigned char *, malloc(HOWMANY + SLOP))) == NULL) 412 return NULL; 413 414 if (file_reset(ms) == -1) 415 goto done; 416 417 switch (file_fsmagic(ms, inname, &sb)) { 418 case -1: /* error */ 419 goto done; 420 case 0: /* nothing found */ 421 break; 422 default: /* matched it and printed type */ 423 rv = 0; 424 goto done; 425 } 426 427 if (inname == NULL) { 428 if (fstat(fd, &sb) == 0 && S_ISFIFO(sb.st_mode)) 429 ispipe = 1; 430 } else { 431 int flags = O_RDONLY|O_BINARY; 432 433 if (stat(inname, &sb) == 0 && S_ISFIFO(sb.st_mode)) { 434 #ifdef O_NONBLOCK 435 flags |= O_NONBLOCK; 436 #endif 437 ispipe = 1; 438 } 439 440 errno = 0; 441 if ((fd = open(inname, flags)) < 0) { 442 if (unreadable_info(ms, sb.st_mode, inname) == -1) 443 goto done; 444 rv = 0; 445 goto done; 446 } 447 #ifdef O_NONBLOCK 448 if ((flags = fcntl(fd, F_GETFL)) != -1) { 449 flags &= ~O_NONBLOCK; 450 (void)fcntl(fd, F_SETFL, flags); 451 } 452 #endif 453 } 454 455 /* 456 * try looking at the first HOWMANY bytes 457 */ 458 if (ispipe) { 459 ssize_t r = 0; 460 461 while ((r = sread(fd, (void *)&buf[nbytes], 462 (size_t)(HOWMANY - nbytes), 1)) > 0) { 463 nbytes += r; 464 if (r < PIPE_BUF) break; 465 } 466 467 if (nbytes == 0) { 468 /* We can not read it, but we were able to stat it. */ 469 if (unreadable_info(ms, sb.st_mode, inname) == -1) 470 goto done; 471 rv = 0; 472 goto done; 473 } 474 475 } else { 476 if ((nbytes = read(fd, (char *)buf, HOWMANY)) == -1) { 477 file_error(ms, errno, "cannot read `%s'", inname); 478 goto done; 479 } 480 } 481 482 (void)memset(buf + nbytes, 0, SLOP); /* NUL terminate */ 483 if (file_buffer(ms, fd, inname, buf, (size_t)nbytes) == -1) 484 goto done; 485 rv = 0; 486 done: 487 free(buf); 488 close_and_restore(ms, inname, fd, &sb); 489 return rv == 0 ? file_getbuffer(ms) : NULL; 490 } 491 492 493 public const char * 494 magic_buffer(struct magic_set *ms, const void *buf, size_t nb) 495 { 496 if (file_reset(ms) == -1) 497 return NULL; 498 /* 499 * The main work is done here! 500 * We have the file name and/or the data buffer to be identified. 501 */ 502 if (file_buffer(ms, -1, NULL, buf, nb) == -1) { 503 return NULL; 504 } 505 return file_getbuffer(ms); 506 } 507 #endif 508 509 public const char * 510 magic_error(struct magic_set *ms) 511 { 512 return (ms->event_flags & EVENT_HAD_ERR) ? ms->o.buf : NULL; 513 } 514 515 public int 516 magic_errno(struct magic_set *ms) 517 { 518 return (ms->event_flags & EVENT_HAD_ERR) ? ms->error : 0; 519 } 520 521 public int 522 magic_setflags(struct magic_set *ms, int flags) 523 { 524 #if !defined(HAVE_UTIME) && !defined(HAVE_UTIMES) 525 if (flags & MAGIC_PRESERVE_ATIME) 526 return -1; 527 #endif 528 ms->flags = flags; 529 return 0; 530 } 531