external/bsd/file/dist/src/magic.c

   1 /*      $NetBSD: magic.c,v 1.10 2015/01/02 21:15:32 christos Exp $      */
   2
   3 /*
   4  * Copyright (c) Christos Zoulas 2003.
   5  * All Rights Reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice immediately at the beginning of the file, without modification,
  12  *    this list of conditions, and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
  21  * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  */
  29
  30 #ifdef WIN32
  31 #include <windows.h>
  32 #include <shlwapi.h>
  33 #endif
  34
  35 #include "file.h"
  36
  37 #ifndef lint
  38 #if 0
  39 FILE_RCSID("@(#)$File: magic.c,v 1.91 2014/12/16 23:18:40 christos Exp $")
  40 #else
  41 __RCSID("$NetBSD: magic.c,v 1.10 2015/01/02 21:15:32 christos Exp $");
  42 #endif
  43 #endif  /* lint */
  44
  45 #include "magic.h"
  46
  47 #include <stdlib.h>
  48 #include <unistd.h>
  49 #include <string.h>
  50 #ifdef QUICK
  51 #include <sys/mman.h>
  52 #endif
  53 #ifdef HAVE_LIMITS_H
  54 #include <limits.h>     /* for PIPE_BUF */
  55 #endif
  56
  57 #if defined(HAVE_UTIMES)
  58 # include <sys/time.h>
  59 #elif defined(HAVE_UTIME)
  60 # if defined(HAVE_SYS_UTIME_H)
  61 #  include <sys/utime.h>
  62 # elif defined(HAVE_UTIME_H)
  63 #  include <utime.h>
  64 # endif
  65 #endif
  66
  67 #ifdef HAVE_UNISTD_H
  68 #include <unistd.h>     /* for read() */
  69 #endif
  70
  71 #ifndef PIPE_BUF
  72 /* Get the PIPE_BUF from pathconf */
  73 #ifdef _PC_PIPE_BUF
  74 #define PIPE_BUF pathconf(".", _PC_PIPE_BUF)
  75 #else
  76 #define PIPE_BUF 512
  77 #endif
  78 #endif
  79
  80 private void close_and_restore(const struct magic_set *, const char *, int,
  81     const struct stat *);
  82 private int unreadable_info(struct magic_set *, mode_t, const char *);
  83 private const char* get_default_magic(void);
  84 #ifndef COMPILE_ONLY
  85 private const char *file_or_fd(struct magic_set *, const char *, int);
  86 #endif
  87
  88 #ifndef STDIN_FILENO
  89 #define STDIN_FILENO    0
  90 #endif
  91
  92 private const char *
  93 get_default_magic(void)
  94 {
  95         static const char hmagic[] = "/.magic/magic.mgc";
  96         static char *default_magic;
  97         char *home, *hmagicpath;
  98
  99 #ifndef WIN32
 100         struct stat st;
 101
 102         if (default_magic) {
 103                 free(default_magic);
 104                 default_magic = NULL;
 105         }
 106         if ((home = getenv("HOME")) == NULL)
 107                 return MAGIC;
 108
 109         if (asprintf(&hmagicpath, "%s/.magic.mgc", home) < 0)
 110                 return MAGIC;
 111         if (stat(hmagicpath, &st) == -1) {
 112                 free(hmagicpath);
 113                 if (asprintf(&hmagicpath, "%s/.magic", home) < 0)
 114                         return MAGIC;
 115                 if (stat(hmagicpath, &st) == -1)
 116                         goto out;
 117                 if (S_ISDIR(st.st_mode)) {
 118                         free(hmagicpath);
 119                         if (asprintf(&hmagicpath, "%s/%s", home, hmagic) < 0)
 120                                 return MAGIC;
 121                         if (access(hmagicpath, R_OK) == -1)
 122                                 goto out;
 123                 }
 124         }
 125
 126         if (asprintf(&default_magic, "%s:%s", hmagicpath, MAGIC) < 0)
 127                 goto out;
 128         free(hmagicpath);
 129         return default_magic;
 130 out:
 131         default_magic = NULL;
 132         free(hmagicpath);
 133         return MAGIC;
 134 #else
 135         char *hmagicp;
 136         char *tmppath = NULL;
 137         LPTSTR dllpath;
 138         hmagicpath = NULL;
 139
 140 #define APPENDPATH() \
 141         do { \
 142                 if (tmppath && access(tmppath, R_OK) != -1) { \
 143                         if (hmagicpath == NULL) \
 144                                 hmagicpath = tmppath; \
 145                         else { \
 146                                 if (asprintf(&hmagicp, "%s%c%s", hmagicpath, \
 147                                     PATHSEP, tmppath) >= 0) { \
 148                                         free(hmagicpath); \
 149                                         hmagicpath = hmagicp; \
 150                                 } \
 151                                 free(tmppath); \
 152                         } \
 153                         tmppath = NULL; \
 154                 } \
 155         } while (/*CONSTCOND*/0)
 156
 157         if (default_magic) {
 158                 free(default_magic);
 159                 default_magic = NULL;
 160         }
 161
 162         /* First, try to get user-specific magic file */
 163         if ((home = getenv("LOCALAPPDATA")) == NULL) {
 164                 if ((home = getenv("USERPROFILE")) != NULL)
 165                         if (asprintf(&tmppath,
 166                             "%s/Local Settings/Application Data%s", home,
 167                             hmagic) < 0)
 168                                 tmppath = NULL;
 169         } else {
 170                 if (asprintf(&tmppath, "%s%s", home, hmagic) < 0)
 171                         tmppath = NULL;
 172         }
 173
 174         APPENDPATH();
 175
 176         /* Second, try to get a magic file from Common Files */
 177         if ((home = getenv("COMMONPROGRAMFILES")) != NULL) {
 178                 if (asprintf(&tmppath, "%s%s", home, hmagic) >= 0)
 179                         APPENDPATH();
 180         }
 181
 182         /* Third, try to get magic file relative to dll location */
 183         dllpath = malloc(sizeof(*dllpath) * (MAX_PATH + 1));
 184         dllpath[MAX_PATH] = 0;  /* just in case long path gets truncated and not null terminated */
 185         if (GetModuleFileNameA(NULL, dllpath, MAX_PATH)){
 186                 PathRemoveFileSpecA(dllpath);
 187                 if (strlen(dllpath) > 3 &&
 188                     stricmp(&dllpath[strlen(dllpath) - 3], "bin") == 0) {
 189                         if (asprintf(&tmppath,
 190                             "%s/../share/misc/magic.mgc", dllpath) >= 0)
 191                                 APPENDPATH();
 192                 } else {
 193                         if (asprintf(&tmppath,
 194                             "%s/share/misc/magic.mgc", dllpath) >= 0)
 195                                 APPENDPATH();
 196                         else if (asprintf(&tmppath,
 197                             "%s/magic.mgc", dllpath) >= 0)
 198                                 APPENDPATH();
 199                 }
 200         }
 201
 202         /* Don't put MAGIC constant - it likely points to a file within MSys
 203         tree */
 204         default_magic = hmagicpath;
 205         return default_magic;
 206 #endif
 207 }
 208
 209 public const char *
 210 magic_getpath(const char *magicfile, int action)
 211 {
 212         if (magicfile != NULL)
 213                 return magicfile;
 214
 215         magicfile = getenv("MAGIC");
 216         if (magicfile != NULL)
 217                 return magicfile;
 218
 219         return action == FILE_LOAD ? get_default_magic() : MAGIC;
 220 }
 221
 222 public struct magic_set *
 223 magic_open(int flags)
 224 {
 225         return file_ms_alloc(flags);
 226 }
 227
 228 private int
 229 unreadable_info(struct magic_set *ms, mode_t md, const char *file)
 230 {
 231         if (file) {
 232                 /* We cannot open it, but we were able to stat it. */
 233                 if (access(file, W_OK) == 0)
 234                         if (file_printf(ms, "writable, ") == -1)
 235                                 return -1;
 236                 if (access(file, X_OK) == 0)
 237                         if (file_printf(ms, "executable, ") == -1)
 238                                 return -1;
 239         }
 240         if (S_ISREG(md))
 241                 if (file_printf(ms, "regular file, ") == -1)
 242                         return -1;
 243         if (file_printf(ms, "no read permission") == -1)
 244                 return -1;
 245         return 0;
 246 }
 247
 248 public void
 249 magic_close(struct magic_set *ms)
 250 {
 251         if (ms == NULL)
 252                 return;
 253         file_ms_free(ms);
 254 }
 255
 256 /*
 257  * load a magic file
 258  */
 259 public int
 260 magic_load(struct magic_set *ms, const char *magicfile)
 261 {
 262         if (ms == NULL)
 263                 return -1;
 264         return file_apprentice(ms, magicfile, FILE_LOAD);
 265 }
 266
 267 #ifndef COMPILE_ONLY
 268 /*
 269  * Install a set of compiled magic buffers.
 270  */
 271 public int
 272 magic_load_buffers(struct magic_set *ms, void **bufs, size_t *sizes,
 273     size_t nbufs)
 274 {
 275         if (ms == NULL)
 276                 return -1;
 277         return buffer_apprentice(ms, (struct magic **)bufs, sizes, nbufs);
 278 }
 279 #endif
 280
 281 public int
 282 magic_compile(struct magic_set *ms, const char *magicfile)
 283 {
 284         if (ms == NULL)
 285                 return -1;
 286         return file_apprentice(ms, magicfile, FILE_COMPILE);
 287 }
 288
 289 public int
 290 magic_check(struct magic_set *ms, const char *magicfile)
 291 {
 292         if (ms == NULL)
 293                 return -1;
 294         return file_apprentice(ms, magicfile, FILE_CHECK);
 295 }
 296
 297 public int
 298 magic_list(struct magic_set *ms, const char *magicfile)
 299 {
 300         if (ms == NULL)
 301                 return -1;
 302         return file_apprentice(ms, magicfile, FILE_LIST);
 303 }
 304
 305 private void
 306 close_and_restore(const struct magic_set *ms, const char *name, int fd,
 307     const struct stat *sb)
 308 {
 309         if (fd == STDIN_FILENO || name == NULL)
 310                 return;
 311         (void) close(fd);
 312
 313         if ((ms->flags & MAGIC_PRESERVE_ATIME) != 0) {
 314                 /*
 315                  * Try to restore access, modification times if read it.
 316                  * This is really *bad* because it will modify the status
 317                  * time of the file... And of course this will affect
 318                  * backup programs
 319                  */
 320 #ifdef HAVE_UTIMES
 321                 struct timeval  utsbuf[2];
 322                 (void)memset(utsbuf, 0, sizeof(utsbuf));
 323                 utsbuf[0].tv_sec = sb->st_atime;
 324                 utsbuf[1].tv_sec = sb->st_mtime;
 325
 326                 (void) utimes(name, utsbuf); /* don't care if loses */
 327 #elif defined(HAVE_UTIME_H) || defined(HAVE_SYS_UTIME_H)
 328                 struct utimbuf  utbuf;
 329
 330                 (void)memset(&utbuf, 0, sizeof(utbuf));
 331                 utbuf.actime = sb->st_atime;
 332                 utbuf.modtime = sb->st_mtime;
 333                 (void) utime(name, &utbuf); /* don't care if loses */
 334 #endif
 335         }
 336 }
 337
 338 #ifndef COMPILE_ONLY
 339
 340 /*
 341  * find type of descriptor
 342  */
 343 public const char *
 344 magic_descriptor(struct magic_set *ms, int fd)
 345 {
 346         if (ms == NULL)
 347                 return NULL;
 348         return file_or_fd(ms, NULL, fd);
 349 }
 350
 351 /*
 352  * find type of named file
 353  */
 354 public const char *
 355 magic_file(struct magic_set *ms, const char *inname)
 356 {
 357         if (ms == NULL)
 358                 return NULL;
 359         return file_or_fd(ms, inname, STDIN_FILENO);
 360 }
 361
 362 private const char *
 363 file_or_fd(struct magic_set *ms, const char *inname, int fd)
 364 {
 365         int     rv = -1;
 366         unsigned char *buf;
 367         struct stat     sb;
 368         ssize_t nbytes = 0;     /* number of bytes read from a datafile */
 369         int     ispipe = 0;
 370         off_t   pos = (off_t)-1;
 371
 372         if (file_reset(ms) == -1)
 373                 goto out;
 374
 375         /*
 376          * one extra for terminating '\0', and
 377          * some overlapping space for matches near EOF
 378          */
 379 #define SLOP (1 + sizeof(union VALUETYPE))
 380         if ((buf = CAST(unsigned char *, malloc(HOWMANY + SLOP))) == NULL)
 381                 return NULL;
 382
 383         switch (file_fsmagic(ms, inname, &sb)) {
 384         case -1:                /* error */
 385                 goto done;
 386         case 0:                 /* nothing found */
 387                 break;
 388         default:                /* matched it and printed type */
 389                 rv = 0;
 390                 goto done;
 391         }
 392
 393 #ifdef WIN32
 394         /* Place stdin in binary mode, so EOF (Ctrl+Z) doesn't stop early. */
 395         if (fd == STDIN_FILENO)
 396                 _setmode(STDIN_FILENO, O_BINARY);
 397 #endif
 398
 399         if (inname == NULL) {
 400                 if (fstat(fd, &sb) == 0 && S_ISFIFO(sb.st_mode))
 401                         ispipe = 1;
 402                 else
 403                         pos = lseek(fd, (off_t)0, SEEK_CUR);
 404         } else {
 405                 int flags = O_RDONLY|O_BINARY;
 406                 int okstat = stat(inname, &sb) == 0;
 407
 408                 if (okstat && S_ISFIFO(sb.st_mode)) {
 409 #ifdef O_NONBLOCK
 410                         flags |= O_NONBLOCK;
 411 #endif
 412                         ispipe = 1;
 413                 }
 414
 415                 errno = 0;
 416                 if ((fd = open(inname, flags)) < 0) {
 417 #ifdef WIN32
 418                         /*
 419                          * Can't stat, can't open.  It may have been opened in
 420                          * fsmagic, so if the user doesn't have read permission,
 421                          * allow it to say so; otherwise an error was probably
 422                          * displayed in fsmagic.
 423                          */
 424                         if (!okstat && errno == EACCES) {
 425                                 sb.st_mode = S_IFBLK;
 426                                 okstat = 1;
 427                         }
 428 #endif
 429                         if (okstat &&
 430                             unreadable_info(ms, sb.st_mode, inname) == -1)
 431                                 goto done;
 432                         rv = 0;
 433                         goto done;
 434                 }
 435 #ifdef O_NONBLOCK
 436                 if ((flags = fcntl(fd, F_GETFL)) != -1) {
 437                         flags &= ~O_NONBLOCK;
 438                         (void)fcntl(fd, F_SETFL, flags);
 439                 }
 440 #endif
 441         }
 442
 443         /*
 444          * try looking at the first HOWMANY bytes
 445          */
 446         if (ispipe) {
 447                 ssize_t r = 0;
 448
 449                 while ((r = sread(fd, (void *)&buf[nbytes],
 450                     (size_t)(HOWMANY - nbytes), 1)) > 0) {
 451                         nbytes += r;
 452                         if (r < PIPE_BUF) break;
 453                 }
 454
 455                 if (nbytes == 0) {
 456                         /* We can not read it, but we were able to stat it. */
 457                         if (unreadable_info(ms, sb.st_mode, inname) == -1)
 458                                 goto done;
 459                         rv = 0;
 460                         goto done;
 461                 }
 462
 463         } else {
 464                 /* Windows refuses to read from a big console buffer. */
 465                 size_t howmany =
 466 #if defined(WIN32) && HOWMANY > 8 * 1024
 467                                 _isatty(fd) ? 8 * 1024 :
 468 #endif
 469                                 HOWMANY;
 470                 if ((nbytes = read(fd, (char *)buf, howmany)) == -1) {
 471                         if (inname == NULL && fd != STDIN_FILENO)
 472                                 file_error(ms, errno, "cannot read fd %d", fd);
 473                         else
 474                                 file_error(ms, errno, "cannot read `%s'",
 475                                     inname == NULL ? "/dev/stdin" : inname);
 476                         goto done;
 477                 }
 478         }
 479
 480         (void)memset(buf + nbytes, 0, SLOP); /* NUL terminate */
 481         if (file_buffer(ms, fd, inname, buf, (size_t)nbytes) == -1)
 482                 goto done;
 483         rv = 0;
 484 done:
 485         free(buf);
 486         if (pos != (off_t)-1)
 487                 (void)lseek(fd, pos, SEEK_SET);
 488         close_and_restore(ms, inname, fd, &sb);
 489 out:
 490         return rv == 0 ? file_getbuffer(ms) : NULL;
 491 }
 492
 493
 494 public const char *
 495 magic_buffer(struct magic_set *ms, const void *buf, size_t nb)
 496 {
 497         if (ms == NULL)
 498                 return NULL;
 499         if (file_reset(ms) == -1)
 500                 return NULL;
 501         /*
 502          * The main work is done here!
 503          * We have the file name and/or the data buffer to be identified.
 504          */
 505         if (file_buffer(ms, -1, NULL, buf, nb) == -1) {
 506                 return NULL;
 507         }
 508         return file_getbuffer(ms);
 509 }
 510 #endif
 511
 512 public const char *
 513 magic_error(struct magic_set *ms)
 514 {
 515         if (ms == NULL)
 516                 return "Magic database is not open";
 517         return (ms->event_flags & EVENT_HAD_ERR) ? ms->o.buf : NULL;
 518 }
 519
 520 public int
 521 magic_errno(struct magic_set *ms)
 522 {
 523         if (ms == NULL)
 524                 return EINVAL;
 525         return (ms->event_flags & EVENT_HAD_ERR) ? ms->error : 0;
 526 }
 527
 528 public int
 529 magic_setflags(struct magic_set *ms, int flags)
 530 {
 531         if (ms == NULL)
 532                 return -1;
 533 #if !defined(HAVE_UTIME) && !defined(HAVE_UTIMES)
 534         if (flags & MAGIC_PRESERVE_ATIME)
 535                 return -1;
 536 #endif
 537         ms->flags = flags;
 538         return 0;
 539 }
 540
 541 public int
 542 magic_version(void)
 543 {
 544         return MAGIC_VERSION;
 545 }
 546
 547 public int
 548 magic_setparam(struct magic_set *ms, int param, const void *val)
 549 {
 550         switch (param) {
 551         case MAGIC_PARAM_INDIR_MAX:
 552                 ms->indir_max = (uint16_t)*(const size_t *)val;
 553                 return 0;
 554         case MAGIC_PARAM_NAME_MAX:
 555                 ms->name_max = (uint16_t)*(const size_t *)val;
 556                 return 0;
 557         case MAGIC_PARAM_ELF_PHNUM_MAX:
 558                 ms->elf_phnum_max = (uint16_t)*(const size_t *)val;
 559                 return 0;
 560         case MAGIC_PARAM_ELF_SHNUM_MAX:
 561                 ms->elf_shnum_max = (uint16_t)*(const size_t *)val;
 562                 return 0;
 563         case MAGIC_PARAM_ELF_NOTES_MAX:
 564                 ms->elf_notes_max = (uint16_t)*(const size_t *)val;
 565                 return 0;
 566         default:
 567                 errno = EINVAL;
 568                 return -1;
 569         }
 570 }
 571
 572 public int
 573 magic_getparam(struct magic_set *ms, int param, void *val)
 574 {
 575         switch (param) {
 576         case MAGIC_PARAM_INDIR_MAX:
 577                 *(size_t *)val = ms->indir_max;
 578                 return 0;
 579         case MAGIC_PARAM_NAME_MAX:
 580                 *(size_t *)val = ms->name_max;
 581                 return 0;
 582         case MAGIC_PARAM_ELF_PHNUM_MAX:
 583                 *(size_t *)val = ms->elf_phnum_max;
 584                 return 0;
 585         case MAGIC_PARAM_ELF_SHNUM_MAX:
 586                 *(size_t *)val = ms->elf_shnum_max;
 587                 return 0;
 588         case MAGIC_PARAM_ELF_NOTES_MAX:
 589                 *(size_t *)val = ms->elf_notes_max;
 590                 return 0;
 591         default:
 592                 errno = EINVAL;
 593                 return -1;
 594         }
 595 }