fsmagic.c 10 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. #ifndef lint
  33. FILE_RCSID("@(#)$File: fsmagic.c,v 1.76 2015/04/09 20:01:41 christos Exp $")
  34. #endif /* lint */
  35. #include "magic.h"
  36. #include <string.h>
  37. #ifdef HAVE_UNISTD_H
  38. #include <unistd.h>
  39. #endif
  40. #include <stdlib.h>
  41. /* Since major is a function on SVR4, we cannot use `ifndef major'. */
  42. #ifdef MAJOR_IN_MKDEV
  43. # include <sys/mkdev.h>
  44. # define HAVE_MAJOR
  45. #endif
  46. #ifdef MAJOR_IN_SYSMACROS
  47. # include <sys/sysmacros.h>
  48. # define HAVE_MAJOR
  49. #endif
  50. #ifdef major /* Might be defined in sys/types.h. */
  51. # define HAVE_MAJOR
  52. #endif
  53. #ifdef WIN32
  54. # define WIN32_LEAN_AND_MEAN
  55. # include <windows.h>
  56. #endif
  57. #ifndef HAVE_MAJOR
  58. # define major(dev) (((dev) >> 8) & 0xff)
  59. # define minor(dev) ((dev) & 0xff)
  60. #endif
  61. #undef HAVE_MAJOR
  62. #ifdef S_IFLNK
  63. private int
  64. bad_link(struct magic_set *ms, int err, char *buf)
  65. {
  66. int mime = ms->flags & MAGIC_MIME;
  67. if ((mime & MAGIC_MIME_TYPE) &&
  68. file_printf(ms, "inode/symlink")
  69. == -1)
  70. return -1;
  71. else if (!mime) {
  72. if (ms->flags & MAGIC_ERROR) {
  73. file_error(ms, err,
  74. "broken symbolic link to %s", buf);
  75. return -1;
  76. }
  77. if (file_printf(ms, "broken symbolic link to %s", buf) == -1)
  78. return -1;
  79. }
  80. return 1;
  81. }
  82. #endif
  83. private int
  84. handle_mime(struct magic_set *ms, int mime, const char *str)
  85. {
  86. if ((mime & MAGIC_MIME_TYPE)) {
  87. if (file_printf(ms, "inode/%s", str) == -1)
  88. return -1;
  89. if ((mime & MAGIC_MIME_ENCODING) && file_printf(ms,
  90. "; charset=") == -1)
  91. return -1;
  92. }
  93. if ((mime & MAGIC_MIME_ENCODING) && file_printf(ms, "binary") == -1)
  94. return -1;
  95. return 0;
  96. }
  97. protected int
  98. file_fsmagic(struct magic_set *ms, const char *fn, struct stat *sb)
  99. {
  100. int ret, did = 0;
  101. int mime = ms->flags & MAGIC_MIME;
  102. #ifdef S_IFLNK
  103. char buf[BUFSIZ+4];
  104. ssize_t nch;
  105. struct stat tstatbuf;
  106. #endif
  107. if (ms->flags & (MAGIC_APPLE|MAGIC_EXTENSION))
  108. return 0;
  109. if (fn == NULL)
  110. return 0;
  111. #define COMMA (did++ ? ", " : "")
  112. /*
  113. * Fstat is cheaper but fails for files you don't have read perms on.
  114. * On 4.2BSD and similar systems, use lstat() to identify symlinks.
  115. */
  116. #ifdef S_IFLNK
  117. if ((ms->flags & MAGIC_SYMLINK) == 0)
  118. ret = lstat(fn, sb);
  119. else
  120. #endif
  121. ret = stat(fn, sb); /* don't merge into if; see "ret =" above */
  122. #ifdef WIN32
  123. {
  124. HANDLE hFile = CreateFile((LPCSTR)fn, 0, FILE_SHARE_DELETE |
  125. FILE_SHARE_READ | FILE_SHARE_WRITE, NULL, OPEN_EXISTING, 0,
  126. NULL);
  127. if (hFile != INVALID_HANDLE_VALUE) {
  128. /*
  129. * Stat failed, but we can still open it - assume it's
  130. * a block device, if nothing else.
  131. */
  132. if (ret) {
  133. sb->st_mode = S_IFBLK;
  134. ret = 0;
  135. }
  136. switch (GetFileType(hFile)) {
  137. case FILE_TYPE_CHAR:
  138. sb->st_mode |= S_IFCHR;
  139. sb->st_mode &= ~S_IFREG;
  140. break;
  141. case FILE_TYPE_PIPE:
  142. sb->st_mode |= S_IFIFO;
  143. sb->st_mode &= ~S_IFREG;
  144. break;
  145. }
  146. CloseHandle(hFile);
  147. }
  148. }
  149. #endif
  150. if (ret) {
  151. if (ms->flags & MAGIC_ERROR) {
  152. file_error(ms, errno, "cannot stat `%s'", fn);
  153. return -1;
  154. }
  155. if (file_printf(ms, "cannot open `%s' (%s)",
  156. fn, strerror(errno)) == -1)
  157. return -1;
  158. return 0;
  159. }
  160. ret = 1;
  161. if (!mime) {
  162. #ifdef S_ISUID
  163. if (sb->st_mode & S_ISUID)
  164. if (file_printf(ms, "%ssetuid", COMMA) == -1)
  165. return -1;
  166. #endif
  167. #ifdef S_ISGID
  168. if (sb->st_mode & S_ISGID)
  169. if (file_printf(ms, "%ssetgid", COMMA) == -1)
  170. return -1;
  171. #endif
  172. #ifdef S_ISVTX
  173. if (sb->st_mode & S_ISVTX)
  174. if (file_printf(ms, "%ssticky", COMMA) == -1)
  175. return -1;
  176. #endif
  177. }
  178. switch (sb->st_mode & S_IFMT) {
  179. case S_IFDIR:
  180. if (mime) {
  181. if (handle_mime(ms, mime, "directory") == -1)
  182. return -1;
  183. } else if (file_printf(ms, "%sdirectory", COMMA) == -1)
  184. return -1;
  185. break;
  186. #ifdef S_IFCHR
  187. case S_IFCHR:
  188. /*
  189. * If -s has been specified, treat character special files
  190. * like ordinary files. Otherwise, just report that they
  191. * are block special files and go on to the next file.
  192. */
  193. if ((ms->flags & MAGIC_DEVICES) != 0) {
  194. ret = 0;
  195. break;
  196. }
  197. if (mime) {
  198. if (handle_mime(ms, mime, "chardevice") == -1)
  199. return -1;
  200. } else {
  201. #ifdef HAVE_STRUCT_STAT_ST_RDEV
  202. # ifdef dv_unit
  203. if (file_printf(ms, "%scharacter special (%d/%d/%d)",
  204. COMMA, major(sb->st_rdev), dv_unit(sb->st_rdev),
  205. dv_subunit(sb->st_rdev)) == -1)
  206. return -1;
  207. # else
  208. if (file_printf(ms, "%scharacter special (%ld/%ld)",
  209. COMMA, (long)major(sb->st_rdev),
  210. (long)minor(sb->st_rdev)) == -1)
  211. return -1;
  212. # endif
  213. #else
  214. if (file_printf(ms, "%scharacter special", COMMA) == -1)
  215. return -1;
  216. #endif
  217. }
  218. break;
  219. #endif
  220. #ifdef S_IFBLK
  221. case S_IFBLK:
  222. /*
  223. * If -s has been specified, treat block special files
  224. * like ordinary files. Otherwise, just report that they
  225. * are block special files and go on to the next file.
  226. */
  227. if ((ms->flags & MAGIC_DEVICES) != 0) {
  228. ret = 0;
  229. break;
  230. }
  231. if (mime) {
  232. if (handle_mime(ms, mime, "blockdevice") == -1)
  233. return -1;
  234. } else {
  235. #ifdef HAVE_STRUCT_STAT_ST_RDEV
  236. # ifdef dv_unit
  237. if (file_printf(ms, "%sblock special (%d/%d/%d)",
  238. COMMA, major(sb->st_rdev), dv_unit(sb->st_rdev),
  239. dv_subunit(sb->st_rdev)) == -1)
  240. return -1;
  241. # else
  242. if (file_printf(ms, "%sblock special (%ld/%ld)",
  243. COMMA, (long)major(sb->st_rdev),
  244. (long)minor(sb->st_rdev)) == -1)
  245. return -1;
  246. # endif
  247. #else
  248. if (file_printf(ms, "%sblock special", COMMA) == -1)
  249. return -1;
  250. #endif
  251. }
  252. break;
  253. #endif
  254. /* TODO add code to handle V7 MUX and Blit MUX files */
  255. #ifdef S_IFIFO
  256. case S_IFIFO:
  257. if((ms->flags & MAGIC_DEVICES) != 0)
  258. break;
  259. if (mime) {
  260. if (handle_mime(ms, mime, "fifo") == -1)
  261. return -1;
  262. } else if (file_printf(ms, "%sfifo (named pipe)", COMMA) == -1)
  263. return -1;
  264. break;
  265. #endif
  266. #ifdef S_IFDOOR
  267. case S_IFDOOR:
  268. if (mime) {
  269. if (handle_mime(ms, mime, "door") == -1)
  270. return -1;
  271. } else if (file_printf(ms, "%sdoor", COMMA) == -1)
  272. return -1;
  273. break;
  274. #endif
  275. #ifdef S_IFLNK
  276. case S_IFLNK:
  277. if ((nch = readlink(fn, buf, BUFSIZ-1)) <= 0) {
  278. if (ms->flags & MAGIC_ERROR) {
  279. file_error(ms, errno, "unreadable symlink `%s'",
  280. fn);
  281. return -1;
  282. }
  283. if (mime) {
  284. if (handle_mime(ms, mime, "symlink") == -1)
  285. return -1;
  286. } else if (file_printf(ms,
  287. "%sunreadable symlink `%s' (%s)", COMMA, fn,
  288. strerror(errno)) == -1)
  289. return -1;
  290. break;
  291. }
  292. buf[nch] = '\0'; /* readlink(2) does not do this */
  293. /* If broken symlink, say so and quit early. */
  294. if (*buf == '/') {
  295. if (stat(buf, &tstatbuf) < 0)
  296. return bad_link(ms, errno, buf);
  297. } else {
  298. char *tmp;
  299. char buf2[BUFSIZ+BUFSIZ+4];
  300. if ((tmp = strrchr(fn, '/')) == NULL) {
  301. tmp = buf; /* in current directory anyway */
  302. } else {
  303. if (tmp - fn + 1 > BUFSIZ) {
  304. if (ms->flags & MAGIC_ERROR) {
  305. file_error(ms, 0,
  306. "path too long: `%s'", buf);
  307. return -1;
  308. }
  309. if (mime) {
  310. if (handle_mime(ms, mime,
  311. "x-path-too-long") == -1)
  312. return -1;
  313. } else if (file_printf(ms,
  314. "%spath too long: `%s'", COMMA,
  315. fn) == -1)
  316. return -1;
  317. break;
  318. }
  319. /* take dir part */
  320. (void)strlcpy(buf2, fn, sizeof buf2);
  321. buf2[tmp - fn + 1] = '\0';
  322. /* plus (rel) link */
  323. (void)strlcat(buf2, buf, sizeof buf2);
  324. tmp = buf2;
  325. }
  326. if (stat(tmp, &tstatbuf) < 0)
  327. return bad_link(ms, errno, buf);
  328. }
  329. /* Otherwise, handle it. */
  330. if ((ms->flags & MAGIC_SYMLINK) != 0) {
  331. const char *p;
  332. ms->flags &= MAGIC_SYMLINK;
  333. p = magic_file(ms, buf);
  334. ms->flags |= MAGIC_SYMLINK;
  335. if (p == NULL)
  336. return -1;
  337. } else { /* just print what it points to */
  338. if (mime) {
  339. if (handle_mime(ms, mime, "symlink") == -1)
  340. return -1;
  341. } else if (file_printf(ms, "%ssymbolic link to %s",
  342. COMMA, buf) == -1)
  343. return -1;
  344. }
  345. break;
  346. #endif
  347. #ifdef S_IFSOCK
  348. #ifndef __COHERENT__
  349. case S_IFSOCK:
  350. if (mime) {
  351. if (handle_mime(ms, mime, "socket") == -1)
  352. return -1;
  353. } else if (file_printf(ms, "%ssocket", COMMA) == -1)
  354. return -1;
  355. break;
  356. #endif
  357. #endif
  358. case S_IFREG:
  359. /*
  360. * regular file, check next possibility
  361. *
  362. * If stat() tells us the file has zero length, report here that
  363. * the file is empty, so we can skip all the work of opening and
  364. * reading the file.
  365. * But if the -s option has been given, we skip this
  366. * optimization, since on some systems, stat() reports zero
  367. * size for raw disk partitions. (If the block special device
  368. * really has zero length, the fact that it is empty will be
  369. * detected and reported correctly when we read the file.)
  370. */
  371. if ((ms->flags & MAGIC_DEVICES) == 0 && sb->st_size == 0) {
  372. if (mime) {
  373. if (handle_mime(ms, mime, "x-empty") == -1)
  374. return -1;
  375. } else if (file_printf(ms, "%sempty", COMMA) == -1)
  376. return -1;
  377. break;
  378. }
  379. ret = 0;
  380. break;
  381. default:
  382. file_error(ms, 0, "invalid mode 0%o", sb->st_mode);
  383. return -1;
  384. /*NOTREACHED*/
  385. }
  386. if (!mime && did && ret == 0) {
  387. if (file_printf(ms, " ") == -1)
  388. return -1;
  389. }
  390. return ret;
  391. }