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 1.69 2010/09/20 14:14:49 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[2 * MAXPATHLEN + 2]; 112 char *home; 113 char hmagicpath[MAXPATHLEN + 1] = { 0 }; 114 115 #ifndef WIN32 116 if ((home = getenv("HOME")) == NULL) 117 return MAGIC; 118 119 (void)snprintf(hmagicpath, sizeof(hmagicpath), "%s%s", home, hmagic); 120 121 if (access(hmagicpath, R_OK) == -1) 122 return MAGIC; 123 124 (void)snprintf(default_magic, sizeof(default_magic), "%s:%s", 125 hmagicpath, MAGIC); 126 #else 127 char *hmagicp = hmagicpath; 128 char tmppath[MAXPATHLEN + 1] = { 0 }; 129 char *hmagicend = &hmagicpath[sizeof(hmagicpath) - 1]; 130 static const char pathsep[] = { PATHSEP, '\0' }; 131 132 #define APPENDPATH() \ 133 if (access(tmppath, R_OK) != -1) 134 hmagicp += snprintf(hmagicp, hmagicend - hmagicp, \ 135 "%s%s", hmagicp == hmagicpath ? "" : pathsep, tmppath) 136 /* First, try to get user-specific magic file */ 137 if ((home = getenv("LOCALAPPDATA")) == NULL) { 138 if ((home = getenv("USERPROFILE")) != NULL) 139 (void)snprintf(tmppath, sizeof(tmppath), 140 "%s/Local Settings/Application Data%s", home, 141 hmagic); 142 } else { 143 (void)snprintf(tmppath, sizeof(tmppath), "%s%s", 144 home, hmagic); 145 } 146 if (tmppath[0] != '\0') { 147 APPENDPATH(); 148 } 149 150 /* Second, try to get a magic file from Common Files */ 151 if ((home = getenv("COMMONPROGRAMFILES")) != NULL) { 152 (void)snprintf(tmppath, sizeof(tmppath), "%s%s", home, hmagic); 153 APPENDPATH(); 154 } 155 156 157 /* Third, try to get magic file relative to dll location */ 158 if (dllpath[0] != 0) { 159 if (strlen(dllpath) > 3 && 160 stricmp(&dllpath[strlen(dllpath) - 3], "bin") == 0) { 161 (void)snprintf(tmppath, sizeof(tmppath), 162 "%s/../share/misc/magic.mgc", dllpath); 163 APPENDPATH(); 164 } else { 165 (void)snprintf(tmppath, sizeof(tmppath), 166 "%s/share/misc/magic.mgc", dllpath); 167 APPENDPATH() 168 else { 169 (void)snprintf(tmppath, sizeof(tmppath), 170 "%s/magic.mgc", dllpath); 171 APPENDPATH(); 172 } 173 } 174 } 175 176 /* Don't put MAGIC constant - it likely points to a file within MSys 177 tree */ 178 (void)strlcpy(default_magic, hmagicpath, sizeof(default_magic)); 179 #endif 180 181 return default_magic; 182 } 183 184 public const char * 185 magic_getpath(const char *magicfile, int action) 186 { 187 if (magicfile != NULL) 188 return magicfile; 189 190 magicfile = getenv("MAGIC"); 191 if (magicfile != NULL) 192 return magicfile; 193 194 return action == FILE_LOAD ? get_default_magic() : MAGIC; 195 } 196 197 public struct magic_set * 198 magic_open(int flags) 199 { 200 struct magic_set *ms; 201 size_t len; 202 203 if ((ms = CAST(struct magic_set *, calloc((size_t)1, 204 sizeof(struct magic_set)))) == NULL) 205 return NULL; 206 207 if (magic_setflags(ms, flags) == -1) { 208 errno = EINVAL; 209 goto free; 210 } 211 212 ms->o.buf = ms->o.pbuf = NULL; 213 len = (ms->c.len = 10) * sizeof(*ms->c.li); 214 215 if ((ms->c.li = CAST(struct level_info *, malloc(len))) == NULL) 216 goto free; 217 218 ms->event_flags = 0; 219 ms->error = -1; 220 ms->mlist = NULL; 221 ms->file = "unknown"; 222 ms->line = 0; 223 return ms; 224 free: 225 free(ms); 226 return NULL; 227 } 228 229 private void 230 free_mlist(struct mlist *mlist) 231 { 232 struct mlist *ml; 233 234 if (mlist == NULL) 235 return; 236 237 for (ml = mlist->next; ml != mlist;) { 238 struct mlist *next = ml->next; 239 struct magic *mg = ml->magic; 240 file_delmagic(mg, ml->mapped, ml->nmagic); 241 free(ml); 242 ml = next; 243 } 244 free(ml); 245 } 246 247 private int 248 unreadable_info(struct magic_set *ms, mode_t md, const char *file) 249 { 250 /* We cannot open it, but we were able to stat it. */ 251 if (access(file, W_OK) == 0) 252 if (file_printf(ms, "writable, ") == -1) 253 return -1; 254 if (access(file, X_OK) == 0) 255 if (file_printf(ms, "executable, ") == -1) 256 return -1; 257 if (S_ISREG(md)) 258 if (file_printf(ms, "regular file, ") == -1) 259 return -1; 260 if (file_printf(ms, "no read permission") == -1) 261 return -1; 262 return 0; 263 } 264 265 public void 266 magic_close(struct magic_set *ms) 267 { 268 free_mlist(ms->mlist); 269 free(ms->o.pbuf); 270 free(ms->o.buf); 271 free(ms->c.li); 272 free(ms); 273 } 274 275 /* 276 * load a magic file 277 */ 278 public int 279 magic_load(struct magic_set *ms, const char *magicfile) 280 { 281 struct mlist *ml = file_apprentice(ms, magicfile, FILE_LOAD); 282 if (ml) { 283 free_mlist(ms->mlist); 284 ms->mlist = ml; 285 return 0; 286 } 287 return -1; 288 } 289 290 public int 291 magic_compile(struct magic_set *ms, const char *magicfile) 292 { 293 struct mlist *ml = file_apprentice(ms, magicfile, FILE_COMPILE); 294 free_mlist(ml); 295 return ml ? 0 : -1; 296 } 297 298 public int 299 magic_check(struct magic_set *ms, const char *magicfile) 300 { 301 struct mlist *ml = file_apprentice(ms, magicfile, FILE_CHECK); 302 free_mlist(ml); 303 return ml ? 0 : -1; 304 } 305 306 public int 307 magic_list(struct magic_set *ms, const char *magicfile) 308 { 309 struct mlist *ml = file_apprentice(ms, magicfile, FILE_LIST); 310 free_mlist(ml); 311 return ml ? 0 : -1; 312 } 313 314 private void 315 close_and_restore(const struct magic_set *ms, const char *name, int fd, 316 const struct stat *sb) 317 { 318 if (fd == STDIN_FILENO) 319 return; 320 (void) close(fd); 321 322 if ((ms->flags & MAGIC_PRESERVE_ATIME) != 0) { 323 /* 324 * Try to restore access, modification times if read it. 325 * This is really *bad* because it will modify the status 326 * time of the file... And of course this will affect 327 * backup programs 328 */ 329 #ifdef HAVE_UTIMES 330 struct timeval utsbuf[2]; 331 (void)memset(utsbuf, 0, sizeof(utsbuf)); 332 utsbuf[0].tv_sec = sb->st_atime; 333 utsbuf[1].tv_sec = sb->st_mtime; 334 335 (void) utimes(name, utsbuf); /* don't care if loses */ 336 #elif defined(HAVE_UTIME_H) || defined(HAVE_SYS_UTIME_H) 337 struct utimbuf utbuf; 338 339 (void)memset(&utbuf, 0, sizeof(utbuf)); 340 utbuf.actime = sb->st_atime; 341 utbuf.modtime = sb->st_mtime; 342 (void) utime(name, &utbuf); /* don't care if loses */ 343 #endif 344 } 345 } 346 347 #ifndef COMPILE_ONLY 348 349 /* 350 * find type of descriptor 351 */ 352 public const char * 353 magic_descriptor(struct magic_set *ms, int fd) 354 { 355 return file_or_fd(ms, NULL, fd); 356 } 357 358 /* 359 * find type of named file 360 */ 361 public const char * 362 magic_file(struct magic_set *ms, const char *inname) 363 { 364 return file_or_fd(ms, inname, STDIN_FILENO); 365 } 366 367 private const char * 368 file_or_fd(struct magic_set *ms, const char *inname, int fd) 369 { 370 int rv = -1; 371 unsigned char *buf; 372 struct stat sb; 373 ssize_t nbytes = 0; /* number of bytes read from a datafile */ 374 int ispipe = 0; 375 376 /* 377 * one extra for terminating '\0', and 378 * some overlapping space for matches near EOF 379 */ 380 #define SLOP (1 + sizeof(union VALUETYPE)) 381 if ((buf = CAST(unsigned char *, malloc(HOWMANY + SLOP))) == NULL) 382 return NULL; 383 384 if (file_reset(ms) == -1) 385 goto done; 386 387 switch (file_fsmagic(ms, inname, &sb)) { 388 case -1: /* error */ 389 goto done; 390 case 0: /* nothing found */ 391 break; 392 default: /* matched it and printed type */ 393 rv = 0; 394 goto done; 395 } 396 397 if (inname == NULL) { 398 if (fstat(fd, &sb) == 0 && S_ISFIFO(sb.st_mode)) 399 ispipe = 1; 400 } else { 401 int flags = O_RDONLY|O_BINARY; 402 403 if (stat(inname, &sb) == 0 && S_ISFIFO(sb.st_mode)) { 404 #ifdef O_NONBLOCK 405 flags |= O_NONBLOCK; 406 #endif 407 ispipe = 1; 408 } 409 410 errno = 0; 411 if ((fd = open(inname, flags)) < 0) { 412 if (unreadable_info(ms, sb.st_mode, inname) == -1) 413 goto done; 414 rv = 0; 415 goto done; 416 } 417 #ifdef O_NONBLOCK 418 if ((flags = fcntl(fd, F_GETFL)) != -1) { 419 flags &= ~O_NONBLOCK; 420 (void)fcntl(fd, F_SETFL, flags); 421 } 422 #endif 423 } 424 425 /* 426 * try looking at the first HOWMANY bytes 427 */ 428 if (ispipe) { 429 ssize_t r = 0; 430 431 while ((r = sread(fd, (void *)&buf[nbytes], 432 (size_t)(HOWMANY - nbytes), 1)) > 0) { 433 nbytes += r; 434 if (r < PIPE_BUF) break; 435 } 436 437 if (nbytes == 0) { 438 /* We can not read it, but we were able to stat it. */ 439 if (unreadable_info(ms, sb.st_mode, inname) == -1) 440 goto done; 441 rv = 0; 442 goto done; 443 } 444 445 } else { 446 if ((nbytes = read(fd, (char *)buf, HOWMANY)) == -1) { 447 file_error(ms, errno, "cannot read `%s'", inname); 448 goto done; 449 } 450 } 451 452 (void)memset(buf + nbytes, 0, SLOP); /* NUL terminate */ 453 if (file_buffer(ms, fd, inname, buf, (size_t)nbytes) == -1) 454 goto done; 455 rv = 0; 456 done: 457 free(buf); 458 close_and_restore(ms, inname, fd, &sb); 459 return rv == 0 ? file_getbuffer(ms) : NULL; 460 } 461 462 463 public const char * 464 magic_buffer(struct magic_set *ms, const void *buf, size_t nb) 465 { 466 if (file_reset(ms) == -1) 467 return NULL; 468 /* 469 * The main work is done here! 470 * We have the file name and/or the data buffer to be identified. 471 */ 472 if (file_buffer(ms, -1, NULL, buf, nb) == -1) { 473 return NULL; 474 } 475 return file_getbuffer(ms); 476 } 477 #endif 478 479 public const char * 480 magic_error(struct magic_set *ms) 481 { 482 return (ms->event_flags & EVENT_HAD_ERR) ? ms->o.buf : NULL; 483 } 484 485 public int 486 magic_errno(struct magic_set *ms) 487 { 488 return (ms->event_flags & EVENT_HAD_ERR) ? ms->error : 0; 489 } 490 491 public int 492 magic_setflags(struct magic_set *ms, int flags) 493 { 494 #if !defined(HAVE_UTIME) && !defined(HAVE_UTIMES) 495 if (flags & MAGIC_PRESERVE_ATIME) 496 return -1; 497 #endif 498 ms->flags = flags; 499 return 0; 500 } 501