contrib/file/src/fsmagic.c

   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  * fsmagic - magic based on filesystem info - directory, special files, etc.
  30  */
  31
  32 #include "file.h"
  33
  34 #ifndef lint
  35 FILE_RCSID("@(#)$File: fsmagic.c,v 1.81 2019/07/16 13:30:32 christos Exp $")
  36 #endif  /* lint */
  37
  38 #include "magic.h"
  39 #include <string.h>
  40 #ifdef HAVE_UNISTD_H
  41 #include <unistd.h>
  42 #endif
  43 #include <stdlib.h>
  44 /* Since major is a function on SVR4, we cannot use `ifndef major'.  */
  45 #ifdef MAJOR_IN_MKDEV
  46 # include <sys/mkdev.h>
  47 # define HAVE_MAJOR
  48 #endif
  49 #ifdef HAVE_SYS_SYSMACROS_H
  50 # include <sys/sysmacros.h>
  51 #endif
  52 #ifdef MAJOR_IN_SYSMACROS
  53 # define HAVE_MAJOR
  54 #endif
  55 #if defined(major) && !defined(HAVE_MAJOR)
  56 /* Might be defined in sys/types.h.  */
  57 # define HAVE_MAJOR
  58 #endif
  59 #ifdef WIN32
  60 # define WIN32_LEAN_AND_MEAN
  61 # include <windows.h>
  62 #endif
  63
  64 #ifndef HAVE_MAJOR
  65 # define major(dev)  (((dev) >> 8) & 0xff)
  66 # define minor(dev)  ((dev) & 0xff)
  67 #endif
  68 #undef HAVE_MAJOR
  69 #ifdef  S_IFLNK
  70 private int
  71 bad_link(struct magic_set *ms, int err, char *buf)
  72 {
  73         int mime = ms->flags & MAGIC_MIME;
  74         if ((mime & MAGIC_MIME_TYPE) &&
  75             file_printf(ms, "inode/symlink")
  76             == -1)
  77                 return -1;
  78         else if (!mime) {
  79                 if (ms->flags & MAGIC_ERROR) {
  80                         file_error(ms, err,
  81                                    "broken symbolic link to %s", buf);
  82                         return -1;
  83                 }
  84                 if (file_printf(ms, "broken symbolic link to %s", buf) == -1)
  85                         return -1;
  86         }
  87         return 1;
  88 }
  89 #endif
  90 private int
  91 handle_mime(struct magic_set *ms, int mime, const char *str)
  92 {
  93         if ((mime & MAGIC_MIME_TYPE)) {
  94                 if (file_printf(ms, "inode/%s", str) == -1)
  95                         return -1;
  96                 if ((mime & MAGIC_MIME_ENCODING) && file_printf(ms,
  97                     "; charset=") == -1)
  98                         return -1;
  99         }
 100         if ((mime & MAGIC_MIME_ENCODING) && file_printf(ms, "binary") == -1)
 101                 return -1;
 102         return 0;
 103 }
 104
 105 protected int
 106 file_fsmagic(struct magic_set *ms, const char *fn, struct stat *sb)
 107 {
 108         int ret, did = 0;
 109         int mime = ms->flags & MAGIC_MIME;
 110         int silent = ms->flags & (MAGIC_APPLE|MAGIC_EXTENSION);
 111 #ifdef  S_IFLNK
 112         char buf[BUFSIZ+4];
 113         ssize_t nch;
 114         struct stat tstatbuf;
 115 #endif
 116
 117         if (fn == NULL)
 118                 return 0;
 119
 120 #define COMMA   (did++ ? ", " : "")
 121         /*
 122          * Fstat is cheaper but fails for files you don't have read perms on.
 123          * On 4.2BSD and similar systems, use lstat() to identify symlinks.
 124          */
 125 #ifdef  S_IFLNK
 126         if ((ms->flags & MAGIC_SYMLINK) == 0)
 127                 ret = lstat(fn, sb);
 128         else
 129 #endif
 130         ret = stat(fn, sb);     /* don't merge into if; see "ret =" above */
 131
 132 #ifdef WIN32
 133         {
 134                 HANDLE hFile = CreateFile((LPCSTR)fn, 0, FILE_SHARE_DELETE |
 135                     FILE_SHARE_READ | FILE_SHARE_WRITE, NULL, OPEN_EXISTING, 0,
 136                     NULL);
 137                 if (hFile != INVALID_HANDLE_VALUE) {
 138                         /*
 139                          * Stat failed, but we can still open it - assume it's
 140                          * a block device, if nothing else.
 141                          */
 142                         if (ret) {
 143                                 sb->st_mode = S_IFBLK;
 144                                 ret = 0;
 145                         }
 146                         switch (GetFileType(hFile)) {
 147                         case FILE_TYPE_CHAR:
 148                                 sb->st_mode |= S_IFCHR;
 149                                 sb->st_mode &= ~S_IFREG;
 150                                 break;
 151                         case FILE_TYPE_PIPE:
 152                                 sb->st_mode |= S_IFIFO;
 153                                 sb->st_mode &= ~S_IFREG;
 154                                 break;
 155                         }
 156                         CloseHandle(hFile);
 157                 }
 158         }
 159 #endif
 160
 161         if (ret) {
 162                 if (ms->flags & MAGIC_ERROR) {
 163                         file_error(ms, errno, "cannot stat `%s'", fn);
 164                         return -1;
 165                 }
 166                 if (file_printf(ms, "cannot open `%s' (%s)",
 167                     fn, strerror(errno)) == -1)
 168                         return -1;
 169                 return 0;
 170         }
 171
 172         ret = 1;
 173         if (!mime && !silent) {
 174 #ifdef S_ISUID
 175                 if (sb->st_mode & S_ISUID)
 176                         if (file_printf(ms, "%ssetuid", COMMA) == -1)
 177                                 return -1;
 178 #endif
 179 #ifdef S_ISGID
 180                 if (sb->st_mode & S_ISGID)
 181                         if (file_printf(ms, "%ssetgid", COMMA) == -1)
 182                                 return -1;
 183 #endif
 184 #ifdef S_ISVTX
 185                 if (sb->st_mode & S_ISVTX)
 186                         if (file_printf(ms, "%ssticky", COMMA) == -1)
 187                                 return -1;
 188 #endif
 189         }
 190
 191         switch (sb->st_mode & S_IFMT) {
 192         case S_IFDIR:
 193                 if (mime) {
 194                         if (handle_mime(ms, mime, "directory") == -1)
 195                                 return -1;
 196                 } else if (silent) {
 197                 } else if (file_printf(ms, "%sdirectory", COMMA) == -1)
 198                         return -1;
 199                 break;
 200 #ifdef S_IFCHR
 201         case S_IFCHR:
 202                 /*
 203                  * If -s has been specified, treat character special files
 204                  * like ordinary files.  Otherwise, just report that they
 205                  * are block special files and go on to the next file.
 206                  */
 207                 if ((ms->flags & MAGIC_DEVICES) != 0) {
 208                         ret = 0;
 209                         break;
 210                 }
 211                 if (mime) {
 212                         if (handle_mime(ms, mime, "chardevice") == -1)
 213                                 return -1;
 214                 } else if (silent) {
 215                 } else {
 216 #ifdef HAVE_STRUCT_STAT_ST_RDEV
 217 # ifdef dv_unit
 218                         if (file_printf(ms, "%scharacter special (%d/%d/%d)",
 219                             COMMA, major(sb->st_rdev), dv_unit(sb->st_rdev),
 220                                         dv_subunit(sb->st_rdev)) == -1)
 221                                 return -1;
 222 # else
 223                         if (file_printf(ms, "%scharacter special (%ld/%ld)",
 224                             COMMA, (long)major(sb->st_rdev),
 225                             (long)minor(sb->st_rdev)) == -1)
 226                                 return -1;
 227 # endif
 228 #else
 229                         if (file_printf(ms, "%scharacter special", COMMA) == -1)
 230                                 return -1;
 231 #endif
 232                 }
 233                 break;
 234 #endif
 235 #ifdef S_IFBLK
 236         case S_IFBLK:
 237                 /*
 238                  * If -s has been specified, treat block special files
 239                  * like ordinary files.  Otherwise, just report that they
 240                  * are block special files and go on to the next file.
 241                  */
 242                 if ((ms->flags & MAGIC_DEVICES) != 0) {
 243                         ret = 0;
 244                         break;
 245                 }
 246                 if (mime) {
 247                         if (handle_mime(ms, mime, "blockdevice") == -1)
 248                                 return -1;
 249                 } else if (silent) {
 250                 } else {
 251 #ifdef HAVE_STRUCT_STAT_ST_RDEV
 252 # ifdef dv_unit
 253                         if (file_printf(ms, "%sblock special (%d/%d/%d)",
 254                             COMMA, major(sb->st_rdev), dv_unit(sb->st_rdev),
 255                             dv_subunit(sb->st_rdev)) == -1)
 256                                 return -1;
 257 # else
 258                         if (file_printf(ms, "%sblock special (%ld/%ld)",
 259                             COMMA, (long)major(sb->st_rdev),
 260                             (long)minor(sb->st_rdev)) == -1)
 261                                 return -1;
 262 # endif
 263 #else
 264                         if (file_printf(ms, "%sblock special", COMMA) == -1)
 265                                 return -1;
 266 #endif
 267                 }
 268                 break;
 269 #endif
 270         /* TODO add code to handle V7 MUX and Blit MUX files */
 271 #ifdef  S_IFIFO
 272         case S_IFIFO:
 273                 if((ms->flags & MAGIC_DEVICES) != 0)
 274                         break;
 275                 if (mime) {
 276                         if (handle_mime(ms, mime, "fifo") == -1)
 277                                 return -1;
 278                 } else if (silent) {
 279                 } else if (file_printf(ms, "%sfifo (named pipe)", COMMA) == -1)
 280                         return -1;
 281                 break;
 282 #endif
 283 #ifdef  S_IFDOOR
 284         case S_IFDOOR:
 285                 if (mime) {
 286                         if (handle_mime(ms, mime, "door") == -1)
 287                                 return -1;
 288                 } else if (silent) {
 289                 } else if (file_printf(ms, "%sdoor", COMMA) == -1)
 290                         return -1;
 291                 break;
 292 #endif
 293 #ifdef  S_IFLNK
 294         case S_IFLNK:
 295                 if ((nch = readlink(fn, buf, BUFSIZ-1)) <= 0) {
 296                         if (ms->flags & MAGIC_ERROR) {
 297                             file_error(ms, errno, "unreadable symlink `%s'",
 298                                 fn);
 299                             return -1;
 300                         }
 301                         if (mime) {
 302                                 if (handle_mime(ms, mime, "symlink") == -1)
 303                                         return -1;
 304                         } else if (silent) {
 305                         } else if (file_printf(ms,
 306                             "%sunreadable symlink `%s' (%s)", COMMA, fn,
 307                             strerror(errno)) == -1)
 308                                 return -1;
 309                         break;
 310                 }
 311                 buf[nch] = '\0';        /* readlink(2) does not do this */
 312
 313                 /* If broken symlink, say so and quit early. */
 314 #ifdef __linux__
 315                 /*
 316                  * linux procfs/devfs makes symlinks like pipe:[3515864880]
 317                  * that we can't stat their readlink output, so stat the
 318                  * original filename instead.
 319                  */
 320                 if (stat(fn, &tstatbuf) < 0)
 321                         return bad_link(ms, errno, buf);
 322 #else
 323                 if (*buf == '/') {
 324                         if (stat(buf, &tstatbuf) < 0)
 325                                 return bad_link(ms, errno, buf);
 326                 } else {
 327                         char *tmp;
 328                         char buf2[BUFSIZ+BUFSIZ+4];
 329
 330                         if ((tmp = strrchr(fn,  '/')) == NULL) {
 331                                 tmp = buf; /* in current directory anyway */
 332                         } else {
 333                                 if (tmp - fn + 1 > BUFSIZ) {
 334                                         if (ms->flags & MAGIC_ERROR) {
 335                                                 file_error(ms, 0,
 336                                                     "path too long: `%s'", buf);
 337                                                 return -1;
 338                                         }
 339                                         if (mime) {
 340                                                 if (handle_mime(ms, mime,
 341                                                     "x-path-too-long") == -1)
 342                                                         return -1;
 343                                         } else if (silent) {
 344                                         } else if (file_printf(ms,
 345                                             "%spath too long: `%s'", COMMA,
 346                                             fn) == -1)
 347                                                 return -1;
 348                                         break;
 349                                 }
 350                                 /* take dir part */
 351                                 (void)strlcpy(buf2, fn, sizeof buf2);
 352                                 buf2[tmp - fn + 1] = '\0';
 353                                 /* plus (rel) link */
 354                                 (void)strlcat(buf2, buf, sizeof buf2);
 355                                 tmp = buf2;
 356                         }
 357                         if (stat(tmp, &tstatbuf) < 0)
 358                                 return bad_link(ms, errno, buf);
 359                 }
 360 #endif
 361
 362                 /* Otherwise, handle it. */
 363                 if ((ms->flags & MAGIC_SYMLINK) != 0) {
 364                         const char *p;
 365                         ms->flags &= MAGIC_SYMLINK;
 366                         p = magic_file(ms, buf);
 367                         ms->flags |= MAGIC_SYMLINK;
 368                         if (p == NULL)
 369                                 return -1;
 370                 } else { /* just print what it points to */
 371                         if (mime) {
 372                                 if (handle_mime(ms, mime, "symlink") == -1)
 373                                         return -1;
 374                         } else if (silent) {
 375                         } else if (file_printf(ms, "%ssymbolic link to %s",
 376                             COMMA, buf) == -1)
 377                                 return -1;
 378                 }
 379                 break;
 380 #endif
 381 #ifdef  S_IFSOCK
 382 #ifndef __COHERENT__
 383         case S_IFSOCK:
 384                 if (mime) {
 385                         if (handle_mime(ms, mime, "socket") == -1)
 386                                 return -1;
 387                 } else if (silent) {
 388                 } else if (file_printf(ms, "%ssocket", COMMA) == -1)
 389                         return -1;
 390                 break;
 391 #endif
 392 #endif
 393         case S_IFREG:
 394                 /*
 395                  * regular file, check next possibility
 396                  *
 397                  * If stat() tells us the file has zero length, report here that
 398                  * the file is empty, so we can skip all the work of opening and
 399                  * reading the file.
 400                  * But if the -s option has been given, we skip this
 401                  * optimization, since on some systems, stat() reports zero
 402                  * size for raw disk partitions. (If the block special device
 403                  * really has zero length, the fact that it is empty will be
 404                  * detected and reported correctly when we read the file.)
 405                  */
 406                 if ((ms->flags & MAGIC_DEVICES) == 0 && sb->st_size == 0) {
 407                         if (mime) {
 408                                 if (handle_mime(ms, mime, "x-empty") == -1)
 409                                         return -1;
 410                         } else if (silent) {
 411                         } else if (file_printf(ms, "%sempty", COMMA) == -1)
 412                                 return -1;
 413                         break;
 414                 }
 415                 ret = 0;
 416                 break;
 417
 418         default:
 419                 file_error(ms, 0, "invalid mode 0%o", sb->st_mode);
 420                 return -1;
 421                 /*NOTREACHED*/
 422         }
 423
 424         if (!silent && !mime && did && ret == 0) {
 425             if (file_printf(ms, " ") == -1)
 426                     return -1;
 427         }
 428         /*
 429          * If we were looking for extensions or apple (silent) it is not our
 430          * job to print here, so don't count this as a match.
 431          */
 432         if (ret == 1 && silent)
 433                 return 0;
 434         return ret;
 435 }