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 1.75 2014/12/04 15:56:46 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 #ifdef  S_IFLNK
 108         char buf[BUFSIZ+4];
 109         ssize_t nch;
 110         struct stat tstatbuf;
 111 #endif
 112
 113         if (ms->flags & MAGIC_APPLE)
 114                 return 0;
 115         if (fn == NULL)
 116                 return 0;
 117
 118 #define COMMA   (did++ ? ", " : "")
 119         /*
 120          * Fstat is cheaper but fails for files you don't have read perms on.
 121          * On 4.2BSD and similar systems, use lstat() to identify symlinks.
 122          */
 123 #ifdef  S_IFLNK
 124         if ((ms->flags & MAGIC_SYMLINK) == 0)
 125                 ret = lstat(fn, sb);
 126         else
 127 #endif
 128         ret = stat(fn, sb);     /* don't merge into if; see "ret =" above */
 129
 130 #ifdef WIN32
 131         {
 132                 HANDLE hFile = CreateFile((LPCSTR)fn, 0, FILE_SHARE_DELETE |
 133                     FILE_SHARE_READ | FILE_SHARE_WRITE, NULL, OPEN_EXISTING, 0,
 134                     NULL);
 135                 if (hFile != INVALID_HANDLE_VALUE) {
 136                         /*
 137                          * Stat failed, but we can still open it - assume it's
 138                          * a block device, if nothing else.
 139                          */
 140                         if (ret) {
 141                                 sb->st_mode = S_IFBLK;
 142                                 ret = 0;
 143                         }
 144                         switch (GetFileType(hFile)) {
 145                         case FILE_TYPE_CHAR:
 146                                 sb->st_mode |= S_IFCHR;
 147                                 sb->st_mode &= ~S_IFREG;
 148                                 break;
 149                         case FILE_TYPE_PIPE:
 150                                 sb->st_mode |= S_IFIFO;
 151                                 sb->st_mode &= ~S_IFREG;
 152                                 break;
 153                         }
 154                         CloseHandle(hFile);
 155                 }
 156         }
 157 #endif
 158
 159         if (ret) {
 160                 if (ms->flags & MAGIC_ERROR) {
 161                         file_error(ms, errno, "cannot stat `%s'", fn);
 162                         return -1;
 163                 }
 164                 if (file_printf(ms, "cannot open `%s' (%s)",
 165                     fn, strerror(errno)) == -1)
 166                         return -1;
 167                 return 0;
 168         }
 169
 170         ret = 1;
 171         if (!mime) {
 172 #ifdef S_ISUID
 173                 if (sb->st_mode & S_ISUID)
 174                         if (file_printf(ms, "%ssetuid", COMMA) == -1)
 175                                 return -1;
 176 #endif
 177 #ifdef S_ISGID
 178                 if (sb->st_mode & S_ISGID)
 179                         if (file_printf(ms, "%ssetgid", COMMA) == -1)
 180                                 return -1;
 181 #endif
 182 #ifdef S_ISVTX
 183                 if (sb->st_mode & S_ISVTX)
 184                         if (file_printf(ms, "%ssticky", COMMA) == -1)
 185                                 return -1;
 186 #endif
 187         }
 188
 189         switch (sb->st_mode & S_IFMT) {
 190         case S_IFDIR:
 191                 if (mime) {
 192                         if (handle_mime(ms, mime, "directory") == -1)
 193                                 return -1;
 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 {
 212 #ifdef HAVE_STRUCT_STAT_ST_RDEV
 213 # ifdef dv_unit
 214                         if (file_printf(ms, "%scharacter special (%d/%d/%d)",
 215                             COMMA, major(sb->st_rdev), dv_unit(sb->st_rdev),
 216                                         dv_subunit(sb->st_rdev)) == -1)
 217                                 return -1;
 218 # else
 219                         if (file_printf(ms, "%scharacter special (%ld/%ld)",
 220                             COMMA, (long)major(sb->st_rdev),
 221                             (long)minor(sb->st_rdev)) == -1)
 222                                 return -1;
 223 # endif
 224 #else
 225                         if (file_printf(ms, "%scharacter special", COMMA) == -1)
 226                                 return -1;
 227 #endif
 228                 }
 229                 break;
 230 #endif
 231 #ifdef S_IFBLK
 232         case S_IFBLK:
 233                 /*
 234                  * If -s has been specified, treat block special files
 235                  * like ordinary files.  Otherwise, just report that they
 236                  * are block special files and go on to the next file.
 237                  */
 238                 if ((ms->flags & MAGIC_DEVICES) != 0) {
 239                         ret = 0;
 240                         break;
 241                 }
 242                 if (mime) {
 243                         if (handle_mime(ms, mime, "blockdevice") == -1)
 244                                 return -1;
 245                 } else {
 246 #ifdef HAVE_STRUCT_STAT_ST_RDEV
 247 # ifdef dv_unit
 248                         if (file_printf(ms, "%sblock special (%d/%d/%d)",
 249                             COMMA, major(sb->st_rdev), dv_unit(sb->st_rdev),
 250                             dv_subunit(sb->st_rdev)) == -1)
 251                                 return -1;
 252 # else
 253                         if (file_printf(ms, "%sblock special (%ld/%ld)",
 254                             COMMA, (long)major(sb->st_rdev),
 255                             (long)minor(sb->st_rdev)) == -1)
 256                                 return -1;
 257 # endif
 258 #else
 259                         if (file_printf(ms, "%sblock special", COMMA) == -1)
 260                                 return -1;
 261 #endif
 262                 }
 263                 break;
 264 #endif
 265         /* TODO add code to handle V7 MUX and Blit MUX files */
 266 #ifdef  S_IFIFO
 267         case S_IFIFO:
 268                 if((ms->flags & MAGIC_DEVICES) != 0)
 269                         break;
 270                 if (mime) {
 271                         if (handle_mime(ms, mime, "fifo") == -1)
 272                                 return -1;
 273                 } else if (file_printf(ms, "%sfifo (named pipe)", COMMA) == -1)
 274                         return -1;
 275                 break;
 276 #endif
 277 #ifdef  S_IFDOOR
 278         case S_IFDOOR:
 279                 if (mime) {
 280                         if (handle_mime(ms, mime, "door") == -1)
 281                                 return -1;
 282                 } else if (file_printf(ms, "%sdoor", COMMA) == -1)
 283                         return -1;
 284                 break;
 285 #endif
 286 #ifdef  S_IFLNK
 287         case S_IFLNK:
 288                 if ((nch = readlink(fn, buf, BUFSIZ-1)) <= 0) {
 289                         if (ms->flags & MAGIC_ERROR) {
 290                             file_error(ms, errno, "unreadable symlink `%s'",
 291                                 fn);
 292                             return -1;
 293                         }
 294                         if (mime) {
 295                                 if (handle_mime(ms, mime, "symlink") == -1)
 296                                         return -1;
 297                         } else if (file_printf(ms,
 298                             "%sunreadable symlink `%s' (%s)", COMMA, fn,
 299                             strerror(errno)) == -1)
 300                                 return -1;
 301                         break;
 302                 }
 303                 buf[nch] = '\0';        /* readlink(2) does not do this */
 304
 305                 /* If broken symlink, say so and quit early. */
 306                 if (*buf == '/') {
 307                         if (stat(buf, &tstatbuf) < 0)
 308                                 return bad_link(ms, errno, buf);
 309                 } else {
 310                         char *tmp;
 311                         char buf2[BUFSIZ+BUFSIZ+4];
 312
 313                         if ((tmp = strrchr(fn,  '/')) == NULL) {
 314                                 tmp = buf; /* in current directory anyway */
 315                         } else {
 316                                 if (tmp - fn + 1 > BUFSIZ) {
 317                                         if (ms->flags & MAGIC_ERROR) {
 318                                                 file_error(ms, 0,
 319                                                     "path too long: `%s'", buf);
 320                                                 return -1;
 321                                         }
 322                                         if (mime) {
 323                                                 if (handle_mime(ms, mime,
 324                                                     "x-path-too-long") == -1)
 325                                                         return -1;
 326                                         } else if (file_printf(ms,
 327                                             "%spath too long: `%s'", COMMA,
 328                                             fn) == -1)
 329                                                 return -1;
 330                                         break;
 331                                 }
 332                                 /* take dir part */
 333                                 (void)strlcpy(buf2, fn, sizeof buf2);
 334                                 buf2[tmp - fn + 1] = '\0';
 335                                 /* plus (rel) link */
 336                                 (void)strlcat(buf2, buf, sizeof buf2);
 337                                 tmp = buf2;
 338                         }
 339                         if (stat(tmp, &tstatbuf) < 0)
 340                                 return bad_link(ms, errno, buf);
 341                 }
 342
 343                 /* Otherwise, handle it. */
 344                 if ((ms->flags & MAGIC_SYMLINK) != 0) {
 345                         const char *p;
 346                         ms->flags &= MAGIC_SYMLINK;
 347                         p = magic_file(ms, buf);
 348                         ms->flags |= MAGIC_SYMLINK;
 349                         if (p == NULL)
 350                                 return -1;
 351                 } else { /* just print what it points to */
 352                         if (mime) {
 353                                 if (handle_mime(ms, mime, "symlink") == -1)
 354                                         return -1;
 355                         } else if (file_printf(ms, "%ssymbolic link to %s",
 356                             COMMA, buf) == -1)
 357                                 return -1;
 358                 }
 359                 break;
 360 #endif
 361 #ifdef  S_IFSOCK
 362 #ifndef __COHERENT__
 363         case S_IFSOCK:
 364                 if (mime) {
 365                         if (handle_mime(ms, mime, "socket") == -1)
 366                                 return -1;
 367                 } else if (file_printf(ms, "%ssocket", COMMA) == -1)
 368                         return -1;
 369                 break;
 370 #endif
 371 #endif
 372         case S_IFREG:
 373                 /*
 374                  * regular file, check next possibility
 375                  *
 376                  * If stat() tells us the file has zero length, report here that
 377                  * the file is empty, so we can skip all the work of opening and
 378                  * reading the file.
 379                  * But if the -s option has been given, we skip this
 380                  * optimization, since on some systems, stat() reports zero
 381                  * size for raw disk partitions. (If the block special device
 382                  * really has zero length, the fact that it is empty will be
 383                  * detected and reported correctly when we read the file.)
 384                  */
 385                 if ((ms->flags & MAGIC_DEVICES) == 0 && sb->st_size == 0) {
 386                         if (mime) {
 387                                 if (handle_mime(ms, mime, "x-empty") == -1)
 388                                         return -1;
 389                         } else if (file_printf(ms, "%sempty", COMMA) == -1)
 390                                 return -1;
 391                         break;
 392                 }
 393                 ret = 0;
 394                 break;
 395
 396         default:
 397                 file_error(ms, 0, "invalid mode 0%o", sb->st_mode);
 398                 return -1;
 399                 /*NOTREACHED*/
 400         }
 401
 402         if (!mime && did && ret == 0) {
 403             if (file_printf(ms, " ") == -1)
 404                     return -1;
 405         }
 406         return ret;
 407 }