fsmagic.c 8.1 KB

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  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. #include "file.h"
  32. #include "magic.h"
  33. #include <string.h>
  34. #ifdef HAVE_UNISTD_H
  35. #include <unistd.h>
  36. #endif
  37. #include <stdlib.h>
  38. #include <sys/stat.h>
  39. /* Since major is a function on SVR4, we cannot use `ifndef major'. */
  40. #ifdef MAJOR_IN_MKDEV
  41. # include <sys/mkdev.h>
  42. # define HAVE_MAJOR
  43. #endif
  44. #ifdef MAJOR_IN_SYSMACROS
  45. # include <sys/sysmacros.h>
  46. # define HAVE_MAJOR
  47. #endif
  48. #ifdef major /* Might be defined in sys/types.h. */
  49. # define HAVE_MAJOR
  50. #endif
  51. #ifndef HAVE_MAJOR
  52. # define major(dev) (((dev) >> 8) & 0xff)
  53. # define minor(dev) ((dev) & 0xff)
  54. #endif
  55. #undef HAVE_MAJOR
  56. #ifndef lint
  57. FILE_RCSID("@(#)$Id: fsmagic.c,v 1.45 2004/11/13 10:19:48 christos Exp $")
  58. #endif /* lint */
  59. protected int
  60. file_fsmagic(struct magic_set *ms, const char *fn, struct stat *sb)
  61. {
  62. int ret = 0;
  63. #ifdef S_IFLNK
  64. char buf[BUFSIZ+4];
  65. int nch;
  66. struct stat tstatbuf;
  67. #endif
  68. if (fn == NULL)
  69. return 0;
  70. /*
  71. * Fstat is cheaper but fails for files you don't have read perms on.
  72. * On 4.2BSD and similar systems, use lstat() to identify symlinks.
  73. */
  74. #ifdef S_IFLNK
  75. if ((ms->flags & MAGIC_SYMLINK) == 0)
  76. ret = lstat(fn, sb);
  77. else
  78. #endif
  79. ret = stat(fn, sb); /* don't merge into if; see "ret =" above */
  80. if (ret) {
  81. if (ms->flags & MAGIC_ERROR) {
  82. file_error(ms, errno, "cannot stat `%s'", fn);
  83. return -1;
  84. }
  85. if (file_printf(ms, "cannot open `%s' (%s)",
  86. fn, strerror(errno)) == -1)
  87. return -1;
  88. ms->haderr++;
  89. return -1;
  90. }
  91. if ((ms->flags & MAGIC_MIME) != 0) {
  92. if ((sb->st_mode & S_IFMT) != S_IFREG) {
  93. if (file_printf(ms, "application/x-not-regular-file")
  94. == -1)
  95. return -1;
  96. return 1;
  97. }
  98. }
  99. else {
  100. #ifdef S_ISUID
  101. if (sb->st_mode & S_ISUID)
  102. if (file_printf(ms, "setuid ") == -1)
  103. return -1;
  104. #endif
  105. #ifdef S_ISGID
  106. if (sb->st_mode & S_ISGID)
  107. if (file_printf(ms, "setgid ") == -1)
  108. return -1;
  109. #endif
  110. #ifdef S_ISVTX
  111. if (sb->st_mode & S_ISVTX)
  112. if (file_printf(ms, "sticky ") == -1)
  113. return -1;
  114. #endif
  115. }
  116. switch (sb->st_mode & S_IFMT) {
  117. case S_IFDIR:
  118. if (file_printf(ms, "directory") == -1)
  119. return -1;
  120. return 1;
  121. #ifdef S_IFCHR
  122. case S_IFCHR:
  123. /*
  124. * If -s has been specified, treat character special files
  125. * like ordinary files. Otherwise, just report that they
  126. * are block special files and go on to the next file.
  127. */
  128. if ((ms->flags & MAGIC_DEVICES) != 0)
  129. break;
  130. #ifdef HAVE_ST_RDEV
  131. # ifdef dv_unit
  132. if (file_printf(ms, "character special (%d/%d/%d)",
  133. major(sb->st_rdev), dv_unit(sb->st_rdev),
  134. dv_subunit(sb->st_rdev)) == -1)
  135. return -1;
  136. # else
  137. if (file_printf(ms, "character special (%ld/%ld)",
  138. (long) major(sb->st_rdev), (long) minor(sb->st_rdev)) == -1)
  139. return -1;
  140. # endif
  141. #else
  142. if (file_printf(ms, "character special") == -1)
  143. return -1;
  144. #endif
  145. return 1;
  146. #endif
  147. #ifdef S_IFBLK
  148. case S_IFBLK:
  149. /*
  150. * If -s has been specified, treat block special files
  151. * like ordinary files. Otherwise, just report that they
  152. * are block special files and go on to the next file.
  153. */
  154. if ((ms->flags & MAGIC_DEVICES) != 0)
  155. break;
  156. #ifdef HAVE_ST_RDEV
  157. # ifdef dv_unit
  158. if (file_printf(ms, "block special (%d/%d/%d)",
  159. major(sb->st_rdev), dv_unit(sb->st_rdev),
  160. dv_subunit(sb->st_rdev)) == -1)
  161. return -1;
  162. # else
  163. if (file_printf(ms, "block special (%ld/%ld)",
  164. (long)major(sb->st_rdev), (long)minor(sb->st_rdev)) == -1)
  165. return -1;
  166. # endif
  167. #else
  168. if (file_printf(ms, "block special") == -1)
  169. return -1;
  170. #endif
  171. return 1;
  172. #endif
  173. /* TODO add code to handle V7 MUX and Blit MUX files */
  174. #ifdef S_IFIFO
  175. case S_IFIFO:
  176. if (file_printf(ms, "fifo (named pipe)") == -1)
  177. return -1;
  178. return 1;
  179. #endif
  180. #ifdef S_IFDOOR
  181. case S_IFDOOR:
  182. if (file_printf(ms, "door") == -1)
  183. return -1;
  184. return 1;
  185. #endif
  186. #ifdef S_IFLNK
  187. case S_IFLNK:
  188. if ((nch = readlink(fn, buf, BUFSIZ-1)) <= 0) {
  189. if (ms->flags & MAGIC_ERROR) {
  190. file_error(ms, errno, "unreadable symlink `%s'",
  191. fn);
  192. return -1;
  193. }
  194. if (file_printf(ms,
  195. "unreadable symlink `%s' (%s)", fn,
  196. strerror(errno)) == -1)
  197. return -1;
  198. return 1;
  199. }
  200. buf[nch] = '\0'; /* readlink(2) forgets this */
  201. /* If broken symlink, say so and quit early. */
  202. if (*buf == '/') {
  203. if (stat(buf, &tstatbuf) < 0) {
  204. if (ms->flags & MAGIC_ERROR) {
  205. file_error(ms, errno,
  206. "broken symbolic link to `%s'", buf);
  207. return -1;
  208. }
  209. if (file_printf(ms, "broken symbolic link to `%s'",
  210. buf) == -1)
  211. return -1;
  212. return 1;
  213. }
  214. }
  215. else {
  216. char *tmp;
  217. char buf2[BUFSIZ+BUFSIZ+4];
  218. if ((tmp = strrchr(fn, '/')) == NULL) {
  219. tmp = buf; /* in current directory anyway */
  220. } else {
  221. if (tmp - fn + 1 > BUFSIZ) {
  222. if (ms->flags & MAGIC_ERROR) {
  223. file_error(ms, 0,
  224. "path too long: `%s'", buf);
  225. return -1;
  226. }
  227. if (file_printf(ms,
  228. "path too long: `%s'", fn) == -1)
  229. return -1;
  230. return 1;
  231. }
  232. (void)strcpy(buf2, fn); /* take dir part */
  233. buf2[tmp - fn + 1] = '\0';
  234. (void)strcat(buf2, buf); /* plus (rel) link */
  235. tmp = buf2;
  236. }
  237. if (stat(tmp, &tstatbuf) < 0) {
  238. if (ms->flags & MAGIC_ERROR) {
  239. file_error(ms, errno,
  240. "broken symbolic link to `%s'",
  241. buf);
  242. return -1;
  243. }
  244. if (file_printf(ms,
  245. "broken symbolic link to `%s'", buf) == -1)
  246. return -1;
  247. return 1;
  248. }
  249. }
  250. /* Otherwise, handle it. */
  251. if ((ms->flags & MAGIC_SYMLINK) != 0) {
  252. const char *p;
  253. ms->flags &= MAGIC_SYMLINK;
  254. p = magic_file(ms, buf);
  255. ms->flags |= MAGIC_SYMLINK;
  256. return p != NULL ? 1 : -1;
  257. } else { /* just print what it points to */
  258. if (file_printf(ms, "symbolic link to `%s'",
  259. buf) == -1)
  260. return -1;
  261. }
  262. return 1;
  263. #endif
  264. #ifdef S_IFSOCK
  265. #ifndef __COHERENT__
  266. case S_IFSOCK:
  267. if (file_printf(ms, "socket") == -1)
  268. return -1;
  269. return 1;
  270. #endif
  271. #endif
  272. case S_IFREG:
  273. break;
  274. default:
  275. file_error(ms, 0, "invalid mode 0%o", sb->st_mode);
  276. return -1;
  277. /*NOTREACHED*/
  278. }
  279. /*
  280. * regular file, check next possibility
  281. *
  282. * If stat() tells us the file has zero length, report here that
  283. * the file is empty, so we can skip all the work of opening and
  284. * reading the file.
  285. * But if the -s option has been given, we skip this optimization,
  286. * since on some systems, stat() reports zero size for raw disk
  287. * partitions. (If the block special device really has zero length,
  288. * the fact that it is empty will be detected and reported correctly
  289. * when we read the file.)
  290. */
  291. if ((ms->flags & MAGIC_DEVICES) == 0 && sb->st_size == 0) {
  292. if (file_printf(ms, (ms->flags & MAGIC_MIME) ?
  293. "application/x-empty" : "empty") == -1)
  294. return -1;
  295. return 1;
  296. }
  297. return 0;
  298. }