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 1.77 2017/05/24 19:17:50 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 MAJOR_IN_SYSMACROS
  50 # include <sys/sysmacros.h>
  51 # define HAVE_MAJOR
  52 #endif
  53 #ifdef major                    /* Might be defined in sys/types.h.  */
  54 # define HAVE_MAJOR
  55 #endif
  56 #ifdef WIN32
  57 # define WIN32_LEAN_AND_MEAN
  58 # include <windows.h>
  59 #endif
  60
  61 #ifndef HAVE_MAJOR
  62 # define major(dev)  (((dev) >> 8) & 0xff)
  63 # define minor(dev)  ((dev) & 0xff)
  64 #endif
  65 #undef HAVE_MAJOR
  66 #ifdef  S_IFLNK
  67 private int
  68 bad_link(struct magic_set *ms, int err, char *buf)
  69 {
  70         int mime = ms->flags & MAGIC_MIME;
  71         if ((mime & MAGIC_MIME_TYPE) &&
  72             file_printf(ms, "inode/symlink")
  73             == -1)
  74                 return -1;
  75         else if (!mime) {
  76                 if (ms->flags & MAGIC_ERROR) {
  77                         file_error(ms, err,
  78                                    "broken symbolic link to %s", buf);
  79                         return -1;
  80                 }
  81                 if (file_printf(ms, "broken symbolic link to %s", buf) == -1)
  82                         return -1;
  83         }
  84         return 1;
  85 }
  86 #endif
  87 private int
  88 handle_mime(struct magic_set *ms, int mime, const char *str)
  89 {
  90         if ((mime & MAGIC_MIME_TYPE)) {
  91                 if (file_printf(ms, "inode/%s", str) == -1)
  92                         return -1;
  93                 if ((mime & MAGIC_MIME_ENCODING) && file_printf(ms,
  94                     "; charset=") == -1)
  95                         return -1;
  96         }
  97         if ((mime & MAGIC_MIME_ENCODING) && file_printf(ms, "binary") == -1)
  98                 return -1;
  99         return 0;
 100 }
 101
 102 protected int
 103 file_fsmagic(struct magic_set *ms, const char *fn, struct stat *sb)
 104 {
 105         int ret, did = 0;
 106         int mime = ms->flags & MAGIC_MIME;
 107         int silent = ms->flags & (MAGIC_APPLE|MAGIC_EXTENSION);
 108 #ifdef  S_IFLNK
 109         char buf[BUFSIZ+4];
 110         ssize_t nch;
 111         struct stat tstatbuf;
 112 #endif
 113
 114         if (fn == NULL)
 115                 return 0;
 116
 117 #define COMMA   (did++ ? ", " : "")
 118         /*
 119          * Fstat is cheaper but fails for files you don't have read perms on.
 120          * On 4.2BSD and similar systems, use lstat() to identify symlinks.
 121          */
 122 #ifdef  S_IFLNK
 123         if ((ms->flags & MAGIC_SYMLINK) == 0)
 124                 ret = lstat(fn, sb);
 125         else
 126 #endif
 127         ret = stat(fn, sb);     /* don't merge into if; see "ret =" above */
 128
 129 #ifdef WIN32
 130         {
 131                 HANDLE hFile = CreateFile((LPCSTR)fn, 0, FILE_SHARE_DELETE |
 132                     FILE_SHARE_READ | FILE_SHARE_WRITE, NULL, OPEN_EXISTING, 0,
 133                     NULL);
 134                 if (hFile != INVALID_HANDLE_VALUE) {
 135                         /*
 136                          * Stat failed, but we can still open it - assume it's
 137                          * a block device, if nothing else.
 138                          */
 139                         if (ret) {
 140                                 sb->st_mode = S_IFBLK;
 141                                 ret = 0;
 142                         }
 143                         switch (GetFileType(hFile)) {
 144                         case FILE_TYPE_CHAR:
 145                                 sb->st_mode |= S_IFCHR;
 146                                 sb->st_mode &= ~S_IFREG;
 147                                 break;
 148                         case FILE_TYPE_PIPE:
 149                                 sb->st_mode |= S_IFIFO;
 150                                 sb->st_mode &= ~S_IFREG;
 151                                 break;
 152                         }
 153                         CloseHandle(hFile);
 154                 }
 155         }
 156 #endif
 157
 158         if (ret) {
 159                 if (ms->flags & MAGIC_ERROR) {
 160                         file_error(ms, errno, "cannot stat `%s'", fn);
 161                         return -1;
 162                 }
 163                 if (file_printf(ms, "cannot open `%s' (%s)",
 164                     fn, strerror(errno)) == -1)
 165                         return -1;
 166                 return 0;
 167         }
 168
 169         ret = 1;
 170         if (!mime && !silent) {
 171 #ifdef S_ISUID
 172                 if (sb->st_mode & S_ISUID)
 173                         if (file_printf(ms, "%ssetuid", COMMA) == -1)
 174                                 return -1;
 175 #endif
 176 #ifdef S_ISGID
 177                 if (sb->st_mode & S_ISGID)
 178                         if (file_printf(ms, "%ssetgid", COMMA) == -1)
 179                                 return -1;
 180 #endif
 181 #ifdef S_ISVTX
 182                 if (sb->st_mode & S_ISVTX)
 183                         if (file_printf(ms, "%ssticky", COMMA) == -1)
 184                                 return -1;
 185 #endif
 186         }
 187
 188         switch (sb->st_mode & S_IFMT) {
 189         case S_IFDIR:
 190                 if (mime) {
 191                         if (handle_mime(ms, mime, "directory") == -1)
 192                                 return -1;
 193                 } else if (silent) {
 194                 } else if (file_printf(ms, "%sdirectory", COMMA) == -1)
 195                         return -1;
 196                 break;
 197 #ifdef S_IFCHR
 198         case S_IFCHR:
 199                 /*
 200                  * If -s has been specified, treat character special files
 201                  * like ordinary files.  Otherwise, just report that they
 202                  * are block special files and go on to the next file.
 203                  */
 204                 if ((ms->flags & MAGIC_DEVICES) != 0) {
 205                         ret = 0;
 206                         break;
 207                 }
 208                 if (mime) {
 209                         if (handle_mime(ms, mime, "chardevice") == -1)
 210                                 return -1;
 211                 } else if (silent) {
 212                 } else {
 213 #ifdef HAVE_STRUCT_STAT_ST_RDEV
 214 # ifdef dv_unit
 215                         if (file_printf(ms, "%scharacter special (%d/%d/%d)",
 216                             COMMA, major(sb->st_rdev), dv_unit(sb->st_rdev),
 217                                         dv_subunit(sb->st_rdev)) == -1)
 218                                 return -1;
 219 # else
 220                         if (file_printf(ms, "%scharacter special (%ld/%ld)",
 221                             COMMA, (long)major(sb->st_rdev),
 222                             (long)minor(sb->st_rdev)) == -1)
 223                                 return -1;
 224 # endif
 225 #else
 226                         if (file_printf(ms, "%scharacter special", COMMA) == -1)
 227                                 return -1;
 228 #endif
 229                 }
 230                 break;
 231 #endif
 232 #ifdef S_IFBLK
 233         case S_IFBLK:
 234                 /*
 235                  * If -s has been specified, treat block special files
 236                  * like ordinary files.  Otherwise, just report that they
 237                  * are block special files and go on to the next file.
 238                  */
 239                 if ((ms->flags & MAGIC_DEVICES) != 0) {
 240                         ret = 0;
 241                         break;
 242                 }
 243                 if (mime) {
 244                         if (handle_mime(ms, mime, "blockdevice") == -1)
 245                                 return -1;
 246                 } else if (silent) {
 247                 } else {
 248 #ifdef HAVE_STRUCT_STAT_ST_RDEV
 249 # ifdef dv_unit
 250                         if (file_printf(ms, "%sblock special (%d/%d/%d)",
 251                             COMMA, major(sb->st_rdev), dv_unit(sb->st_rdev),
 252                             dv_subunit(sb->st_rdev)) == -1)
 253                                 return -1;
 254 # else
 255                         if (file_printf(ms, "%sblock special (%ld/%ld)",
 256                             COMMA, (long)major(sb->st_rdev),
 257                             (long)minor(sb->st_rdev)) == -1)
 258                                 return -1;
 259 # endif
 260 #else
 261                         if (file_printf(ms, "%sblock special", COMMA) == -1)
 262                                 return -1;
 263 #endif
 264                 }
 265                 break;
 266 #endif
 267         /* TODO add code to handle V7 MUX and Blit MUX files */
 268 #ifdef  S_IFIFO
 269         case S_IFIFO:
 270                 if((ms->flags & MAGIC_DEVICES) != 0)
 271                         break;
 272                 if (mime) {
 273                         if (handle_mime(ms, mime, "fifo") == -1)
 274                                 return -1;
 275                 } else if (silent) {
 276                 } else if (file_printf(ms, "%sfifo (named pipe)", COMMA) == -1)
 277                         return -1;
 278                 break;
 279 #endif
 280 #ifdef  S_IFDOOR
 281         case S_IFDOOR:
 282                 if (mime) {
 283                         if (handle_mime(ms, mime, "door") == -1)
 284                                 return -1;
 285                 } else if (silent) {
 286                 } else if (file_printf(ms, "%sdoor", COMMA) == -1)
 287                         return -1;
 288                 break;
 289 #endif
 290 #ifdef  S_IFLNK
 291         case S_IFLNK:
 292                 if ((nch = readlink(fn, buf, BUFSIZ-1)) <= 0) {
 293                         if (ms->flags & MAGIC_ERROR) {
 294                             file_error(ms, errno, "unreadable symlink `%s'",
 295                                 fn);
 296                             return -1;
 297                         }
 298                         if (mime) {
 299                                 if (handle_mime(ms, mime, "symlink") == -1)
 300                                         return -1;
 301                         } else if (silent) {
 302                         } else if (file_printf(ms,
 303                             "%sunreadable symlink `%s' (%s)", COMMA, fn,
 304                             strerror(errno)) == -1)
 305                                 return -1;
 306                         break;
 307                 }
 308                 buf[nch] = '\0';        /* readlink(2) does not do this */
 309
 310                 /* If broken symlink, say so and quit early. */
 311                 if (*buf == '/') {
 312                         if (stat(buf, &tstatbuf) < 0)
 313                                 return bad_link(ms, errno, buf);
 314                 } else {
 315                         char *tmp;
 316                         char buf2[BUFSIZ+BUFSIZ+4];
 317
 318                         if ((tmp = strrchr(fn,  '/')) == NULL) {
 319                                 tmp = buf; /* in current directory anyway */
 320                         } else {
 321                                 if (tmp - fn + 1 > BUFSIZ) {
 322                                         if (ms->flags & MAGIC_ERROR) {
 323                                                 file_error(ms, 0,
 324                                                     "path too long: `%s'", buf);
 325                                                 return -1;
 326                                         }
 327                                         if (mime) {
 328                                                 if (handle_mime(ms, mime,
 329                                                     "x-path-too-long") == -1)
 330                                                         return -1;
 331                                         } else if (silent) {
 332                                         } else if (file_printf(ms,
 333                                             "%spath too long: `%s'", COMMA,
 334                                             fn) == -1)
 335                                                 return -1;
 336                                         break;
 337                                 }
 338                                 /* take dir part */
 339                                 (void)strlcpy(buf2, fn, sizeof buf2);
 340                                 buf2[tmp - fn + 1] = '\0';
 341                                 /* plus (rel) link */
 342                                 (void)strlcat(buf2, buf, sizeof buf2);
 343                                 tmp = buf2;
 344                         }
 345                         if (stat(tmp, &tstatbuf) < 0)
 346                                 return bad_link(ms, errno, buf);
 347                 }
 348
 349                 /* Otherwise, handle it. */
 350                 if ((ms->flags & MAGIC_SYMLINK) != 0) {
 351                         const char *p;
 352                         ms->flags &= MAGIC_SYMLINK;
 353                         p = magic_file(ms, buf);
 354                         ms->flags |= MAGIC_SYMLINK;
 355                         if (p == NULL)
 356                                 return -1;
 357                 } else { /* just print what it points to */
 358                         if (mime) {
 359                                 if (handle_mime(ms, mime, "symlink") == -1)
 360                                         return -1;
 361                         } else if (silent) {
 362                         } else if (file_printf(ms, "%ssymbolic link to %s",
 363                             COMMA, buf) == -1)
 364                                 return -1;
 365                 }
 366                 break;
 367 #endif
 368 #ifdef  S_IFSOCK
 369 #ifndef __COHERENT__
 370         case S_IFSOCK:
 371                 if (mime) {
 372                         if (handle_mime(ms, mime, "socket") == -1)
 373                                 return -1;
 374                 } else if (silent) {
 375                 } else if (file_printf(ms, "%ssocket", COMMA) == -1)
 376                         return -1;
 377                 break;
 378 #endif
 379 #endif
 380         case S_IFREG:
 381                 /*
 382                  * regular file, check next possibility
 383                  *
 384                  * If stat() tells us the file has zero length, report here that
 385                  * the file is empty, so we can skip all the work of opening and
 386                  * reading the file.
 387                  * But if the -s option has been given, we skip this
 388                  * optimization, since on some systems, stat() reports zero
 389                  * size for raw disk partitions. (If the block special device
 390                  * really has zero length, the fact that it is empty will be
 391                  * detected and reported correctly when we read the file.)
 392                  */
 393                 if ((ms->flags & MAGIC_DEVICES) == 0 && sb->st_size == 0) {
 394                         if (mime) {
 395                                 if (handle_mime(ms, mime, "x-empty") == -1)
 396                                         return -1;
 397                         } else if (silent) {
 398                         } else if (file_printf(ms, "%sempty", COMMA) == -1)
 399                                 return -1;
 400                         break;
 401                 }
 402                 ret = 0;
 403                 break;
 404
 405         default:
 406                 file_error(ms, 0, "invalid mode 0%o", sb->st_mode);
 407                 return -1;
 408                 /*NOTREACHED*/
 409         }
 410
 411         if (!silent && !mime && did && ret == 0) {
 412             if (file_printf(ms, " ") == -1)
 413                     return -1;
 414         }
 415         return ret;
 416 }