1 /* $NetBSD: fsmagic.c,v 1.11 2015/01/02 21:15:32 christos Exp $ */
2
3 /*
4 * Copyright (c) Ian F. Darwin 1986-1995.
5 * Software written by Ian F. Darwin and others;
6 * maintained 1995-present by Christos Zoulas and others.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice immediately at the beginning of the file, without modification,
13 * this list of conditions, and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
22 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * SUCH DAMAGE.
29 */
30 /*
31 * fsmagic - magic based on filesystem info - directory, special files, etc.
32 */
33
34 #include "file.h"
35
36 #ifndef lint
37 #if 0
38 FILE_RCSID("@(#)$File: fsmagic.c,v 1.75 2014/12/04 15:56:46 christos Exp $")
39 #else
40 __RCSID("$NetBSD: fsmagic.c,v 1.11 2015/01/02 21:15:32 christos Exp $");
41 #endif
42 #endif /* lint */
43
44 #include "magic.h"
45 #include <string.h>
46 #ifdef HAVE_UNISTD_H
47 #include <unistd.h>
48 #endif
49 #include <stdlib.h>
50 /* Since major is a function on SVR4, we cannot use `ifndef major'. */
51 #ifdef MAJOR_IN_MKDEV
52 # include <sys/mkdev.h>
53 # define HAVE_MAJOR
54 #endif
55 #ifdef MAJOR_IN_SYSMACROS
56 # include <sys/sysmacros.h>
57 # define HAVE_MAJOR
58 #endif
59 #ifdef major /* Might be defined in sys/types.h. */
60 # define HAVE_MAJOR
61 #endif
62 #ifdef WIN32
63 # define WIN32_LEAN_AND_MEAN
64 # include <windows.h>
65 #endif
66
67 #ifndef HAVE_MAJOR
68 # define major(dev) (((dev) >> 8) & 0xff)
69 # define minor(dev) ((dev) & 0xff)
70 #endif
71 #undef HAVE_MAJOR
72 #ifdef S_IFLNK
73 private int
bad_link(struct magic_set * ms,int err,char * buf)74 bad_link(struct magic_set *ms, int err, char *buf)
75 {
76 int mime = ms->flags & MAGIC_MIME;
77 if ((mime & MAGIC_MIME_TYPE) &&
78 file_printf(ms, "inode/symlink")
79 == -1)
80 return -1;
81 else if (!mime) {
82 if (ms->flags & MAGIC_ERROR) {
83 file_error(ms, err,
84 "broken symbolic link to %s", buf);
85 return -1;
86 }
87 if (file_printf(ms, "broken symbolic link to %s", buf) == -1)
88 return -1;
89 }
90 return 1;
91 }
92 #endif
93 private int
handle_mime(struct magic_set * ms,int mime,const char * str)94 handle_mime(struct magic_set *ms, int mime, const char *str)
95 {
96 if ((mime & MAGIC_MIME_TYPE)) {
97 if (file_printf(ms, "inode/%s", str) == -1)
98 return -1;
99 if ((mime & MAGIC_MIME_ENCODING) && file_printf(ms,
100 "; charset=") == -1)
101 return -1;
102 }
103 if ((mime & MAGIC_MIME_ENCODING) && file_printf(ms, "binary") == -1)
104 return -1;
105 return 0;
106 }
107
108 protected int
file_fsmagic(struct magic_set * ms,const char * fn,struct stat * sb)109 file_fsmagic(struct magic_set *ms, const char *fn, struct stat *sb)
110 {
111 int ret, did = 0;
112 int mime = ms->flags & MAGIC_MIME;
113 #ifdef S_IFLNK
114 char buf[BUFSIZ+4];
115 ssize_t nch;
116 struct stat tstatbuf;
117 #endif
118
119 if (ms->flags & MAGIC_APPLE)
120 return 0;
121 if (fn == NULL)
122 return 0;
123
124 #define COMMA (did++ ? ", " : "")
125 /*
126 * Fstat is cheaper but fails for files you don't have read perms on.
127 * On 4.2BSD and similar systems, use lstat() to identify symlinks.
128 */
129 #ifdef S_IFLNK
130 if ((ms->flags & MAGIC_SYMLINK) == 0)
131 ret = lstat(fn, sb);
132 else
133 #endif
134 ret = stat(fn, sb); /* don't merge into if; see "ret =" above */
135
136 #ifdef WIN32
137 {
138 HANDLE hFile = CreateFile((LPCSTR)fn, 0, FILE_SHARE_DELETE |
139 FILE_SHARE_READ | FILE_SHARE_WRITE, NULL, OPEN_EXISTING, 0,
140 NULL);
141 if (hFile != INVALID_HANDLE_VALUE) {
142 /*
143 * Stat failed, but we can still open it - assume it's
144 * a block device, if nothing else.
145 */
146 if (ret) {
147 sb->st_mode = S_IFBLK;
148 ret = 0;
149 }
150 switch (GetFileType(hFile)) {
151 case FILE_TYPE_CHAR:
152 sb->st_mode |= S_IFCHR;
153 sb->st_mode &= ~S_IFREG;
154 break;
155 case FILE_TYPE_PIPE:
156 sb->st_mode |= S_IFIFO;
157 sb->st_mode &= ~S_IFREG;
158 break;
159 }
160 CloseHandle(hFile);
161 }
162 }
163 #endif
164
165 if (ret) {
166 if (ms->flags & MAGIC_ERROR) {
167 file_error(ms, errno, "cannot stat `%s'", fn);
168 return -1;
169 }
170 if (file_printf(ms, "cannot open `%s' (%s)",
171 fn, strerror(errno)) == -1)
172 return -1;
173 return 0;
174 }
175
176 ret = 1;
177 if (!mime) {
178 #ifdef S_ISUID
179 if (sb->st_mode & S_ISUID)
180 if (file_printf(ms, "%ssetuid", COMMA) == -1)
181 return -1;
182 #endif
183 #ifdef S_ISGID
184 if (sb->st_mode & S_ISGID)
185 if (file_printf(ms, "%ssetgid", COMMA) == -1)
186 return -1;
187 #endif
188 #ifdef S_ISVTX
189 if (sb->st_mode & S_ISVTX)
190 if (file_printf(ms, "%ssticky", COMMA) == -1)
191 return -1;
192 #endif
193 }
194
195 switch (sb->st_mode & S_IFMT) {
196 case S_IFDIR:
197 if (mime) {
198 if (handle_mime(ms, mime, "directory") == -1)
199 return -1;
200 } else if (file_printf(ms, "%sdirectory", COMMA) == -1)
201 return -1;
202 break;
203 #ifdef S_IFCHR
204 case S_IFCHR:
205 /*
206 * If -s has been specified, treat character special files
207 * like ordinary files. Otherwise, just report that they
208 * are block special files and go on to the next file.
209 */
210 if ((ms->flags & MAGIC_DEVICES) != 0) {
211 ret = 0;
212 break;
213 }
214 if (mime) {
215 if (handle_mime(ms, mime, "chardevice") == -1)
216 return -1;
217 } else {
218 #ifdef HAVE_STRUCT_STAT_ST_RDEV
219 # ifdef dv_unit
220 if (file_printf(ms, "%scharacter special (%d/%d/%d)",
221 COMMA, major(sb->st_rdev), dv_unit(sb->st_rdev),
222 dv_subunit(sb->st_rdev)) == -1)
223 return -1;
224 # else
225 if (file_printf(ms, "%scharacter special (%ld/%ld)",
226 COMMA, (long)major(sb->st_rdev),
227 (long)minor(sb->st_rdev)) == -1)
228 return -1;
229 # endif
230 #else
231 if (file_printf(ms, "%scharacter special", COMMA) == -1)
232 return -1;
233 #endif
234 }
235 break;
236 #endif
237 #ifdef S_IFBLK
238 case S_IFBLK:
239 /*
240 * If -s has been specified, treat block special files
241 * like ordinary files. Otherwise, just report that they
242 * are block special files and go on to the next file.
243 */
244 if ((ms->flags & MAGIC_DEVICES) != 0) {
245 ret = 0;
246 break;
247 }
248 if (mime) {
249 if (handle_mime(ms, mime, "blockdevice") == -1)
250 return -1;
251 } else {
252 #ifdef HAVE_STRUCT_STAT_ST_RDEV
253 # ifdef dv_unit
254 if (file_printf(ms, "%sblock special (%d/%d/%d)",
255 COMMA, major(sb->st_rdev), dv_unit(sb->st_rdev),
256 dv_subunit(sb->st_rdev)) == -1)
257 return -1;
258 # else
259 if (file_printf(ms, "%sblock special (%ld/%ld)",
260 COMMA, (long)major(sb->st_rdev),
261 (long)minor(sb->st_rdev)) == -1)
262 return -1;
263 # endif
264 #else
265 if (file_printf(ms, "%sblock special", COMMA) == -1)
266 return -1;
267 #endif
268 }
269 break;
270 #endif
271 /* TODO add code to handle V7 MUX and Blit MUX files */
272 #ifdef S_IFIFO
273 case S_IFIFO:
274 if((ms->flags & MAGIC_DEVICES) != 0)
275 break;
276 if (mime) {
277 if (handle_mime(ms, mime, "fifo") == -1)
278 return -1;
279 } else if (file_printf(ms, "%sfifo (named pipe)", COMMA) == -1)
280 return -1;
281 break;
282 #endif
283 #ifdef S_IFDOOR
284 case S_IFDOOR:
285 if (mime) {
286 if (handle_mime(ms, mime, "door") == -1)
287 return -1;
288 } else if (file_printf(ms, "%sdoor", COMMA) == -1)
289 return -1;
290 break;
291 #endif
292 #ifdef S_IFLNK
293 case S_IFLNK:
294 if ((nch = readlink(fn, buf, BUFSIZ-1)) <= 0) {
295 if (ms->flags & MAGIC_ERROR) {
296 file_error(ms, errno, "unreadable symlink `%s'",
297 fn);
298 return -1;
299 }
300 if (mime) {
301 if (handle_mime(ms, mime, "symlink") == -1)
302 return -1;
303 } else if (file_printf(ms,
304 "%sunreadable symlink `%s' (%s)", COMMA, fn,
305 strerror(errno)) == -1)
306 return -1;
307 break;
308 }
309 buf[nch] = '\0'; /* readlink(2) does not do this */
310
311 /* If broken symlink, say so and quit early. */
312 if (*buf == '/') {
313 if (stat(buf, &tstatbuf) < 0)
314 return bad_link(ms, errno, buf);
315 } else {
316 char *tmp;
317 char buf2[BUFSIZ+BUFSIZ+4];
318
319 if ((tmp = strrchr(fn, '/')) == NULL) {
320 tmp = buf; /* in current directory anyway */
321 } else {
322 if (tmp - fn + 1 > BUFSIZ) {
323 if (ms->flags & MAGIC_ERROR) {
324 file_error(ms, 0,
325 "path too long: `%s'", buf);
326 return -1;
327 }
328 if (mime) {
329 if (handle_mime(ms, mime,
330 "x-path-too-long") == -1)
331 return -1;
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 (file_printf(ms, "%ssymbolic link to %s",
362 COMMA, buf) == -1)
363 return -1;
364 }
365 break;
366 #endif
367 #ifdef S_IFSOCK
368 #ifndef __COHERENT__
369 case S_IFSOCK:
370 if (mime) {
371 if (handle_mime(ms, mime, "socket") == -1)
372 return -1;
373 } else if (file_printf(ms, "%ssocket", COMMA) == -1)
374 return -1;
375 break;
376 #endif
377 #endif
378 case S_IFREG:
379 /*
380 * regular file, check next possibility
381 *
382 * If stat() tells us the file has zero length, report here that
383 * the file is empty, so we can skip all the work of opening and
384 * reading the file.
385 * But if the -s option has been given, we skip this
386 * optimization, since on some systems, stat() reports zero
387 * size for raw disk partitions. (If the block special device
388 * really has zero length, the fact that it is empty will be
389 * detected and reported correctly when we read the file.)
390 */
391 if ((ms->flags & MAGIC_DEVICES) == 0 && sb->st_size == 0) {
392 if (mime) {
393 if (handle_mime(ms, mime, "x-empty") == -1)
394 return -1;
395 } else if (file_printf(ms, "%sempty", COMMA) == -1)
396 return -1;
397 break;
398 }
399 ret = 0;
400 break;
401
402 default:
403 file_error(ms, 0, "invalid mode 0%o", sb->st_mode);
404 return -1;
405 /*NOTREACHED*/
406 }
407
408 if (!mime && did && ret == 0) {
409 if (file_printf(ms, " ") == -1)
410 return -1;
411 }
412 return ret;
413 }
414