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 1.82 2022/04/11 18:14:41 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 HAVE_SYS_SYSMACROS_H
50 # include <sys/sysmacros.h>
51 #endif
52 #ifdef MAJOR_IN_SYSMACROS
53 # define HAVE_MAJOR
54 #endif
55 #if defined(major) && !defined(HAVE_MAJOR)
56 /* Might be defined in sys/types.h. */
57 # define HAVE_MAJOR
58 #endif
59 #ifdef WIN32
60 # define WIN32_LEAN_AND_MEAN
61 # include <windows.h>
62 #endif
63
64 #ifndef HAVE_MAJOR
65 # define major(dev) (((dev) >> 8) & 0xff)
66 # define minor(dev) ((dev) & 0xff)
67 #endif
68 #undef HAVE_MAJOR
69 #ifdef S_IFLNK
70 private int
bad_link(struct magic_set * ms,int err,char * buf)71 bad_link(struct magic_set *ms, int err, char *buf)
72 {
73 int mime = ms->flags & MAGIC_MIME;
74 if ((mime & MAGIC_MIME_TYPE) &&
75 file_printf(ms, "inode/symlink")
76 == -1)
77 return -1;
78 else if (!mime) {
79 if (ms->flags & MAGIC_ERROR) {
80 file_error(ms, err,
81 "broken symbolic link to %s", buf);
82 return -1;
83 }
84 if (file_printf(ms, "broken symbolic link to %s", buf) == -1)
85 return -1;
86 }
87 return 1;
88 }
89 #endif
90 private int
handle_mime(struct magic_set * ms,int mime,const char * str)91 handle_mime(struct magic_set *ms, int mime, const char *str)
92 {
93 if ((mime & MAGIC_MIME_TYPE)) {
94 if (file_printf(ms, "inode/%s", str) == -1)
95 return -1;
96 if ((mime & MAGIC_MIME_ENCODING) && file_printf(ms,
97 "; charset=") == -1)
98 return -1;
99 }
100 if ((mime & MAGIC_MIME_ENCODING) && file_printf(ms, "binary") == -1)
101 return -1;
102 return 0;
103 }
104
105 protected int
file_fsmagic(struct magic_set * ms,const char * fn,struct stat * sb)106 file_fsmagic(struct magic_set *ms, const char *fn, struct stat *sb)
107 {
108 int ret, did = 0;
109 int mime = ms->flags & MAGIC_MIME;
110 int silent = ms->flags & (MAGIC_APPLE|MAGIC_EXTENSION);
111 #ifdef S_IFLNK
112 char buf[BUFSIZ+4];
113 ssize_t nch;
114 struct stat tstatbuf;
115 #endif
116
117 if (fn == NULL)
118 return 0;
119
120 #define COMMA (did++ ? ", " : "")
121 /*
122 * Fstat is cheaper but fails for files you don't have read perms on.
123 * On 4.2BSD and similar systems, use lstat() to identify symlinks.
124 */
125 #ifdef S_IFLNK
126 if ((ms->flags & MAGIC_SYMLINK) == 0)
127 ret = lstat(fn, sb);
128 else
129 #endif
130 ret = stat(fn, sb); /* don't merge into if; see "ret =" above */
131
132 #ifdef WIN32
133 {
134 HANDLE hFile = CreateFile((LPCSTR)fn, 0, FILE_SHARE_DELETE |
135 FILE_SHARE_READ | FILE_SHARE_WRITE, NULL, OPEN_EXISTING, 0,
136 NULL);
137 if (hFile != INVALID_HANDLE_VALUE) {
138 /*
139 * Stat failed, but we can still open it - assume it's
140 * a block device, if nothing else.
141 */
142 if (ret) {
143 sb->st_mode = S_IFBLK;
144 ret = 0;
145 }
146 switch (GetFileType(hFile)) {
147 case FILE_TYPE_CHAR:
148 sb->st_mode |= S_IFCHR;
149 sb->st_mode &= ~S_IFREG;
150 break;
151 case FILE_TYPE_PIPE:
152 sb->st_mode |= S_IFIFO;
153 sb->st_mode &= ~S_IFREG;
154 break;
155 }
156 CloseHandle(hFile);
157 }
158 }
159 #endif
160
161 if (ret) {
162 if (ms->flags & MAGIC_ERROR) {
163 file_error(ms, errno, "cannot stat `%s'", fn);
164 return -1;
165 }
166 if (file_printf(ms, "cannot open `%s' (%s)",
167 fn, strerror(errno)) == -1)
168 return -1;
169 return 0;
170 }
171
172 ret = 1;
173 if (!mime && !silent) {
174 #ifdef S_ISUID
175 if (sb->st_mode & S_ISUID)
176 if (file_printf(ms, "%ssetuid", COMMA) == -1)
177 return -1;
178 #endif
179 #ifdef S_ISGID
180 if (sb->st_mode & S_ISGID)
181 if (file_printf(ms, "%ssetgid", COMMA) == -1)
182 return -1;
183 #endif
184 #ifdef S_ISVTX
185 if (sb->st_mode & S_ISVTX)
186 if (file_printf(ms, "%ssticky", COMMA) == -1)
187 return -1;
188 #endif
189 }
190
191 switch (sb->st_mode & S_IFMT) {
192 case S_IFDIR:
193 if (mime) {
194 if (handle_mime(ms, mime, "directory") == -1)
195 return -1;
196 } else if (silent) {
197 } else if (file_printf(ms, "%sdirectory", COMMA) == -1)
198 return -1;
199 break;
200 #ifdef S_IFCHR
201 case S_IFCHR:
202 /*
203 * If -s has been specified, treat character special files
204 * like ordinary files. Otherwise, just report that they
205 * are block special files and go on to the next file.
206 */
207 if ((ms->flags & MAGIC_DEVICES) != 0) {
208 ret = 0;
209 break;
210 }
211 if (mime) {
212 if (handle_mime(ms, mime, "chardevice") == -1)
213 return -1;
214 } else if (silent) {
215 } else {
216 #ifdef HAVE_STRUCT_STAT_ST_RDEV
217 # ifdef dv_unit
218 if (file_printf(ms, "%scharacter special (%d/%d/%d)",
219 COMMA, major(sb->st_rdev), dv_unit(sb->st_rdev),
220 dv_subunit(sb->st_rdev)) == -1)
221 return -1;
222 # else
223 if (file_printf(ms, "%scharacter special (%ld/%ld)",
224 COMMA, (long)major(sb->st_rdev),
225 (long)minor(sb->st_rdev)) == -1)
226 return -1;
227 # endif
228 #else
229 if (file_printf(ms, "%scharacter special", COMMA) == -1)
230 return -1;
231 #endif
232 }
233 break;
234 #endif
235 #ifdef S_IFBLK
236 case S_IFBLK:
237 /*
238 * If -s has been specified, treat block special files
239 * like ordinary files. Otherwise, just report that they
240 * are block special files and go on to the next file.
241 */
242 if ((ms->flags & MAGIC_DEVICES) != 0) {
243 ret = 0;
244 break;
245 }
246 if (mime) {
247 if (handle_mime(ms, mime, "blockdevice") == -1)
248 return -1;
249 } else if (silent) {
250 } else {
251 #ifdef HAVE_STRUCT_STAT_ST_RDEV
252 # ifdef dv_unit
253 if (file_printf(ms, "%sblock special (%d/%d/%d)",
254 COMMA, major(sb->st_rdev), dv_unit(sb->st_rdev),
255 dv_subunit(sb->st_rdev)) == -1)
256 return -1;
257 # else
258 if (file_printf(ms, "%sblock special (%ld/%ld)",
259 COMMA, (long)major(sb->st_rdev),
260 (long)minor(sb->st_rdev)) == -1)
261 return -1;
262 # endif
263 #else
264 if (file_printf(ms, "%sblock special", COMMA) == -1)
265 return -1;
266 #endif
267 }
268 break;
269 #endif
270 /* TODO add code to handle V7 MUX and Blit MUX files */
271 #ifdef S_IFIFO
272 case S_IFIFO:
273 if((ms->flags & MAGIC_DEVICES) != 0)
274 break;
275 if (mime) {
276 if (handle_mime(ms, mime, "fifo") == -1)
277 return -1;
278 } else if (silent) {
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 (silent) {
289 } else if (file_printf(ms, "%sdoor", COMMA) == -1)
290 return -1;
291 break;
292 #endif
293 #ifdef S_IFLNK
294 case S_IFLNK:
295 if ((nch = readlink(fn, buf, BUFSIZ-1)) <= 0) {
296 if (ms->flags & MAGIC_ERROR) {
297 file_error(ms, errno, "unreadable symlink `%s'",
298 fn);
299 return -1;
300 }
301 if (mime) {
302 if (handle_mime(ms, mime, "symlink") == -1)
303 return -1;
304 } else if (silent) {
305 } else if (file_printf(ms,
306 "%sunreadable symlink `%s' (%s)", COMMA, fn,
307 strerror(errno)) == -1)
308 return -1;
309 break;
310 }
311 buf[nch] = '\0'; /* readlink(2) does not do this */
312
313 /* If broken symlink, say so and quit early. */
314 #ifdef __linux__
315 /*
316 * linux procfs/devfs makes symlinks like pipe:[3515864880]
317 * that we can't stat their readlink output, so stat the
318 * original filename instead.
319 */
320 if (stat(fn, &tstatbuf) < 0)
321 return bad_link(ms, errno, buf);
322 #else
323 if (*buf == '/') {
324 if (stat(buf, &tstatbuf) < 0)
325 return bad_link(ms, errno, buf);
326 } else {
327 char *tmp;
328 char buf2[BUFSIZ+BUFSIZ+4];
329
330 if ((tmp = CCAST(char *, strrchr(fn, '/'))) == NULL) {
331 tmp = buf; /* in current directory anyway */
332 } else {
333 if (tmp - fn + 1 > BUFSIZ) {
334 if (ms->flags & MAGIC_ERROR) {
335 file_error(ms, 0,
336 "path too long: `%s'", buf);
337 return -1;
338 }
339 if (mime) {
340 if (handle_mime(ms, mime,
341 "x-path-too-long") == -1)
342 return -1;
343 } else if (silent) {
344 } else if (file_printf(ms,
345 "%spath too long: `%s'", COMMA,
346 fn) == -1)
347 return -1;
348 break;
349 }
350 /* take dir part */
351 (void)strlcpy(buf2, fn, sizeof buf2);
352 buf2[tmp - fn + 1] = '\0';
353 /* plus (rel) link */
354 (void)strlcat(buf2, buf, sizeof buf2);
355 tmp = buf2;
356 }
357 if (stat(tmp, &tstatbuf) < 0)
358 return bad_link(ms, errno, buf);
359 }
360 #endif
361
362 /* Otherwise, handle it. */
363 if ((ms->flags & MAGIC_SYMLINK) != 0) {
364 const char *p;
365 ms->flags &= MAGIC_SYMLINK;
366 p = magic_file(ms, buf);
367 ms->flags |= MAGIC_SYMLINK;
368 if (p == NULL)
369 return -1;
370 } else { /* just print what it points to */
371 if (mime) {
372 if (handle_mime(ms, mime, "symlink") == -1)
373 return -1;
374 } else if (silent) {
375 } else if (file_printf(ms, "%ssymbolic link to %s",
376 COMMA, buf) == -1)
377 return -1;
378 }
379 break;
380 #endif
381 #ifdef S_IFSOCK
382 #ifndef __COHERENT__
383 case S_IFSOCK:
384 if (mime) {
385 if (handle_mime(ms, mime, "socket") == -1)
386 return -1;
387 } else if (silent) {
388 } else if (file_printf(ms, "%ssocket", COMMA) == -1)
389 return -1;
390 break;
391 #endif
392 #endif
393 case S_IFREG:
394 /*
395 * regular file, check next possibility
396 *
397 * If stat() tells us the file has zero length, report here that
398 * the file is empty, so we can skip all the work of opening and
399 * reading the file.
400 * But if the -s option has been given, we skip this
401 * optimization, since on some systems, stat() reports zero
402 * size for raw disk partitions. (If the block special device
403 * really has zero length, the fact that it is empty will be
404 * detected and reported correctly when we read the file.)
405 */
406 if ((ms->flags & MAGIC_DEVICES) == 0 && sb->st_size == 0) {
407 if (mime) {
408 if (handle_mime(ms, mime, "x-empty") == -1)
409 return -1;
410 } else if (silent) {
411 } else if (file_printf(ms, "%sempty", COMMA) == -1)
412 return -1;
413 break;
414 }
415 ret = 0;
416 break;
417
418 default:
419 file_error(ms, 0, "invalid mode 0%o", sb->st_mode);
420 return -1;
421 /*NOTREACHED*/
422 }
423
424 if (!silent && !mime && did && ret == 0) {
425 if (file_printf(ms, " ") == -1)
426 return -1;
427 }
428 /*
429 * If we were looking for extensions or apple (silent) it is not our
430 * job to print here, so don't count this as a match.
431 */
432 if (ret == 1 && silent)
433 return 0;
434 return ret;
435 }
436