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. return 1;
  89. }
  90. if ((ms->flags & MAGIC_MIME) != 0) {
  91. if ((sb->st_mode & S_IFMT) != S_IFREG) {
  92. if (file_printf(ms, "application/x-not-regular-file")
  93. == -1)
  94. return -1;
  95. return 1;
  96. }
  97. }
  98. else {
  99. #ifdef S_ISUID
  100. if (sb->st_mode & S_ISUID)
  101. if (file_printf(ms, "setuid ") == -1)
  102. return -1;
  103. #endif
  104. #ifdef S_ISGID
  105. if (sb->st_mode & S_ISGID)
  106. if (file_printf(ms, "setgid ") == -1)
  107. return -1;
  108. #endif
  109. #ifdef S_ISVTX
  110. if (sb->st_mode & S_ISVTX)
  111. if (file_printf(ms, "sticky ") == -1)
  112. return -1;
  113. #endif
  114. }
  115. switch (sb->st_mode & S_IFMT) {
  116. case S_IFDIR:
  117. if (file_printf(ms, "directory") == -1)
  118. return -1;
  119. return 1;
  120. #ifdef S_IFCHR
  121. case S_IFCHR:
  122. /*
  123. * If -s has been specified, treat character special files
  124. * like ordinary files. Otherwise, just report that they
  125. * are block special files and go on to the next file.
  126. */
  127. if ((ms->flags & MAGIC_DEVICES) != 0)
  128. break;
  129. #ifdef HAVE_ST_RDEV
  130. # ifdef dv_unit
  131. if (file_printf(ms, "character special (%d/%d/%d)",
  132. major(sb->st_rdev), dv_unit(sb->st_rdev),
  133. dv_subunit(sb->st_rdev)) == -1)
  134. return -1;
  135. # else
  136. if (file_printf(ms, "character special (%ld/%ld)",
  137. (long) major(sb->st_rdev), (long) minor(sb->st_rdev)) == -1)
  138. return -1;
  139. # endif
  140. #else
  141. if (file_printf(ms, "character special") == -1)
  142. return -1;
  143. #endif
  144. return 1;
  145. #endif
  146. #ifdef S_IFBLK
  147. case S_IFBLK:
  148. /*
  149. * If -s has been specified, treat block special files
  150. * like ordinary files. Otherwise, just report that they
  151. * are block special files and go on to the next file.
  152. */
  153. if ((ms->flags & MAGIC_DEVICES) != 0)
  154. break;
  155. #ifdef HAVE_ST_RDEV
  156. # ifdef dv_unit
  157. if (file_printf(ms, "block special (%d/%d/%d)",
  158. major(sb->st_rdev), dv_unit(sb->st_rdev),
  159. dv_subunit(sb->st_rdev)) == -1)
  160. return -1;
  161. # else
  162. if (file_printf(ms, "block special (%ld/%ld)",
  163. (long)major(sb->st_rdev), (long)minor(sb->st_rdev)) == -1)
  164. return -1;
  165. # endif
  166. #else
  167. if (file_printf(ms, "block special") == -1)
  168. return -1;
  169. #endif
  170. return 1;
  171. #endif
  172. /* TODO add code to handle V7 MUX and Blit MUX files */
  173. #ifdef S_IFIFO
  174. case S_IFIFO:
  175. if (file_printf(ms, "fifo (named pipe)") == -1)
  176. return -1;
  177. return 1;
  178. #endif
  179. #ifdef S_IFDOOR
  180. case S_IFDOOR:
  181. if (file_printf(ms, "door") == -1)
  182. return -1;
  183. return 1;
  184. #endif
  185. #ifdef S_IFLNK
  186. case S_IFLNK:
  187. if ((nch = readlink(fn, buf, BUFSIZ-1)) <= 0) {
  188. if (ms->flags & MAGIC_ERROR) {
  189. file_error(ms, errno, "unreadable symlink `%s'",
  190. fn);
  191. return -1;
  192. }
  193. if (file_printf(ms,
  194. "unreadable symlink `%s' (%s)", fn,
  195. strerror(errno)) == -1)
  196. return -1;
  197. return 1;
  198. }
  199. buf[nch] = '\0'; /* readlink(2) forgets this */
  200. /* If broken symlink, say so and quit early. */
  201. if (*buf == '/') {
  202. if (stat(buf, &tstatbuf) < 0) {
  203. if (ms->flags & MAGIC_ERROR) {
  204. file_error(ms, errno,
  205. "broken symbolic link to `%s'", buf);
  206. return -1;
  207. }
  208. if (file_printf(ms, "broken symbolic link to `%s'",
  209. buf) == -1)
  210. return -1;
  211. return 1;
  212. }
  213. }
  214. else {
  215. char *tmp;
  216. char buf2[BUFSIZ+BUFSIZ+4];
  217. if ((tmp = strrchr(fn, '/')) == NULL) {
  218. tmp = buf; /* in current directory anyway */
  219. } else {
  220. if (tmp - fn + 1 > BUFSIZ) {
  221. if (ms->flags & MAGIC_ERROR) {
  222. file_error(ms, 0,
  223. "path too long: `%s'", buf);
  224. return -1;
  225. }
  226. if (file_printf(ms,
  227. "path too long: `%s'", fn) == -1)
  228. return -1;
  229. return 1;
  230. }
  231. (void)strcpy(buf2, fn); /* take dir part */
  232. buf2[tmp - fn + 1] = '\0';
  233. (void)strcat(buf2, buf); /* plus (rel) link */
  234. tmp = buf2;
  235. }
  236. if (stat(tmp, &tstatbuf) < 0) {
  237. if (ms->flags & MAGIC_ERROR) {
  238. file_error(ms, errno,
  239. "broken symbolic link to `%s'",
  240. buf);
  241. return -1;
  242. }
  243. if (file_printf(ms,
  244. "broken symbolic link to `%s'", buf) == -1)
  245. return -1;
  246. return 1;
  247. }
  248. }
  249. /* Otherwise, handle it. */
  250. if ((ms->flags & MAGIC_SYMLINK) != 0) {
  251. const char *p;
  252. ms->flags &= MAGIC_SYMLINK;
  253. p = magic_file(ms, buf);
  254. ms->flags |= MAGIC_SYMLINK;
  255. return p != NULL ? 1 : -1;
  256. } else { /* just print what it points to */
  257. if (file_printf(ms, "symbolic link to `%s'",
  258. buf) == -1)
  259. return -1;
  260. }
  261. return 1;
  262. #endif
  263. #ifdef S_IFSOCK
  264. #ifndef __COHERENT__
  265. case S_IFSOCK:
  266. if (file_printf(ms, "socket") == -1)
  267. return -1;
  268. return 1;
  269. #endif
  270. #endif
  271. case S_IFREG:
  272. break;
  273. default:
  274. file_error(ms, 0, "invalid mode 0%o", sb->st_mode);
  275. return -1;
  276. /*NOTREACHED*/
  277. }
  278. /*
  279. * regular file, check next possibility
  280. *
  281. * If stat() tells us the file has zero length, report here that
  282. * the file is empty, so we can skip all the work of opening and
  283. * reading the file.
  284. * But if the -s option has been given, we skip this optimization,
  285. * since on some systems, stat() reports zero size for raw disk
  286. * partitions. (If the block special device really has zero length,
  287. * the fact that it is empty will be detected and reported correctly
  288. * when we read the file.)
  289. */
  290. if ((ms->flags & MAGIC_DEVICES) == 0 && sb->st_size == 0) {
  291. if (file_printf(ms, (ms->flags & MAGIC_MIME) ?
  292. "application/x-empty" : "empty") == -1)
  293. return -1;
  294. return 1;
  295. }
  296. return 0;
  297. }