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
35FILE_RCSID("@(#)$File: fsmagic.c,v 1.60 2009/05/08 17:41:59 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 MAJOR_IN_SYSMACROS
50# include <sys/sysmacros.h>
51# define HAVE_MAJOR
52#endif
53#ifdef major			/* Might be defined in sys/types.h.  */
54# define HAVE_MAJOR
55#endif
56
57#ifndef HAVE_MAJOR
58# define major(dev)  (((dev) >> 8) & 0xff)
59# define minor(dev)  ((dev) & 0xff)
60#endif
61#undef HAVE_MAJOR
62
63private int
64bad_link(struct magic_set *ms, int err, char *buf)
65{
66	const char *errfmt;
67	int mime = ms->flags & MAGIC_MIME;
68	if ((mime & MAGIC_MIME_TYPE) &&
69	    file_printf(ms, "application/x-symlink")
70	    == -1)
71		return -1;
72	else if (!mime) {
73		if (err == ELOOP)
74			errfmt = "symbolic link in a loop";
75		else
76			errfmt = "broken symbolic link to %s";
77		if (ms->flags & MAGIC_ERROR) {
78			file_error(ms, err, errfmt, buf);
79			return -1;
80		}
81		if (file_printf(ms, errfmt, buf) == -1)
82			return -1;
83	}
84	return 1;
85}
86
87private int
88handle_mime(struct magic_set *ms, int mime, const char *str)
89{
90	if ((mime & MAGIC_MIME_TYPE)) {
91		if (file_printf(ms, "application/%s", str) == -1)
92			return -1;
93		if ((mime & MAGIC_MIME_ENCODING) && file_printf(ms,
94		    "; charset=") == -1)
95			return -1;
96	}
97	if ((mime & MAGIC_MIME_ENCODING) && file_printf(ms, "binary") == -1)
98		return -1;
99	return 0;
100}
101
102protected int
103file_fsmagic(struct magic_set *ms, const char *fn, struct stat *sb)
104{
105	int ret = 0;
106	int mime = ms->flags & MAGIC_MIME;
107#ifdef	S_IFLNK
108	char buf[BUFSIZ+4];
109	ssize_t nch;
110	struct stat tstatbuf;
111#endif
112
113	if (ms->flags & MAGIC_APPLE)
114		return 0;
115	if (fn == NULL)
116		return 0;
117
118	/*
119	 * Fstat is cheaper but fails for files you don't have read perms on.
120	 * On 4.2BSD and similar systems, use lstat() to identify symlinks.
121	 */
122#ifdef	S_IFLNK
123	if ((ms->flags & MAGIC_SYMLINK) == 0)
124		ret = lstat(fn, sb);
125	else
126#endif
127	ret = stat(fn, sb);	/* don't merge into if; see "ret =" above */
128
129#ifdef	S_IFLNK
130	/* POSIX says pretend symlinks to nonexistant files
131	 have the -h option */
132	if (ret && (ms->flags & MAGIC_SYMLINK) != 0) {
133		ret = lstat(fn, sb);
134	}
135#endif
136
137	if (ret) {
138		if (ms->flags & MAGIC_ERROR) {
139			file_error(ms, errno, "cannot stat `%s'", fn);
140			return -1;
141		}
142		if (file_printf(ms, "cannot open `%s' (%s)",
143		    fn, strerror(errno)) == -1)
144			return -1;
145		return 1;
146	}
147
148	if (!mime) {
149#ifdef S_ISUID
150		if (sb->st_mode & S_ISUID)
151			if (file_printf(ms, "setuid ") == -1)
152				return -1;
153#endif
154#ifdef S_ISGID
155		if (sb->st_mode & S_ISGID)
156			if (file_printf(ms, "setgid ") == -1)
157				return -1;
158#endif
159#ifdef S_ISVTX
160		if (sb->st_mode & S_ISVTX)
161			if (file_printf(ms, "sticky ") == -1)
162				return -1;
163#endif
164	}
165
166	switch (sb->st_mode & S_IFMT) {
167	case S_IFDIR:
168		if (mime) {
169			if (handle_mime(ms, mime, "x-directory") == -1)
170				return -1;
171		} else if (file_printf(ms, "directory") == -1)
172			return -1;
173		return 1;
174#ifdef S_IFCHR
175	case S_IFCHR:
176		/*
177		 * If -s has been specified, treat character special files
178		 * like ordinary files.  Otherwise, just report that they
179		 * are block special files and go on to the next file.
180		 */
181		if ((ms->flags & MAGIC_DEVICES) != 0)
182			break;
183		if (mime) {
184			if (handle_mime(ms, mime, "x-character-device") == -1)
185				return -1;
186		} else {
187#ifdef HAVE_STAT_ST_RDEV
188# ifdef dv_unit
189			if (file_printf(ms, "character special (%d/%d/%d)",
190			    major(sb->st_rdev), dv_unit(sb->st_rdev),
191					dv_subunit(sb->st_rdev)) == -1)
192				return -1;
193# else
194			if (file_printf(ms, "character special (%ld/%ld)",
195			    (long)major(sb->st_rdev), (long)minor(sb->st_rdev))
196			    == -1)
197				return -1;
198# endif
199#else
200			if (file_printf(ms, "character special") == -1)
201				return -1;
202#endif
203		}
204		return 1;
205#endif
206#ifdef S_IFBLK
207	case S_IFBLK:
208		/*
209		 * If -s has been specified, treat block special files
210		 * like ordinary files.  Otherwise, just report that they
211		 * are block special files and go on to the next file.
212		 */
213		if ((ms->flags & MAGIC_DEVICES) != 0)
214			break;
215		if (mime) {
216			if (handle_mime(ms, mime, "x-block-device") == -1)
217				return -1;
218		} else {
219#ifdef HAVE_STAT_ST_RDEV
220# ifdef dv_unit
221			if (file_printf(ms, "block special (%d/%d/%d)",
222					major(sb->st_rdev), dv_unit(sb->st_rdev),
223					dv_subunit(sb->st_rdev)) == -1)
224				return -1;
225# else
226			if (file_printf(ms, "block special (%ld/%ld)",
227					(long)major(sb->st_rdev), (long)minor(sb->st_rdev)) == -1)
228				return -1;
229# endif
230#else
231			if (file_printf(ms, "block special") == -1)
232				return -1;
233#endif
234		}
235		return 1;
236#endif
237	/* TODO add code to handle V7 MUX and Blit MUX files */
238#ifdef	S_IFIFO
239	case S_IFIFO:
240		if((ms->flags & MAGIC_DEVICES) != 0)
241			break;
242		if (mime) {
243			if (handle_mime(ms, mime, "x-fifo") == -1)
244				return -1;
245		} else if (file_printf(ms, "fifo (named pipe)") == -1)
246			return -1;
247		return 1;
248#endif
249#ifdef	S_IFDOOR
250	case S_IFDOOR:
251		if (mime) {
252			if (handle_mime(ms, mime, "x-door") == -1)
253				return -1;
254		} else if (file_printf(ms, "door") == -1)
255			return -1;
256		return 1;
257#endif
258#ifdef	S_IFLNK
259	case S_IFLNK:
260		if ((nch = readlink(fn, buf, BUFSIZ-1)) <= 0) {
261			if (ms->flags & MAGIC_ERROR) {
262			    file_error(ms, errno, "unreadable symlink `%s'",
263				fn);
264			    return -1;
265			}
266			if (mime) {
267				if (handle_mime(ms, mime, "x-symlink") == -1)
268					return -1;
269			} else if (file_printf(ms,
270			    "unreadable symlink `%s' (%s)", fn,
271			    strerror(errno)) == -1)
272				return -1;
273			return 1;
274		}
275		buf[nch] = '\0';	/* readlink(2) does not do this */
276
277		/* If broken symlink, say so and quit early. */
278		if (*buf == '/') {
279			if (stat(buf, &tstatbuf) < 0)
280				return bad_link(ms, errno, buf);
281		} else {
282			char *tmp;
283			char buf2[BUFSIZ+BUFSIZ+4];
284
285			if ((tmp = strrchr(fn,  '/')) == NULL) {
286				tmp = buf; /* in current directory anyway */
287			} else {
288				if (tmp - fn + 1 > BUFSIZ) {
289					if (ms->flags & MAGIC_ERROR) {
290						file_error(ms, 0,
291						    "path too long: `%s'", buf);
292						return -1;
293					}
294					if (mime) {
295						if (handle_mime(ms, mime,
296						    "x-path-too-long") == -1)
297							return -1;
298					} else if (file_printf(ms,
299					    "path too long: `%s'", fn) == -1)
300						return -1;
301					return 1;
302				}
303				/* take dir part */
304				(void)strlcpy(buf2, fn, sizeof buf2);
305				buf2[tmp - fn + 1] = '\0';
306				/* plus (rel) link */
307				(void)strlcat(buf2, buf, sizeof buf2);
308				tmp = buf2;
309			}
310			if (stat(tmp, &tstatbuf) < 0)
311				return bad_link(ms, errno, buf);
312		}
313
314		/* Otherwise, handle it. */
315		if ((ms->flags & MAGIC_SYMLINK) != 0) {
316			const char *p;
317			ms->flags &= MAGIC_SYMLINK;
318			p = magic_file(ms, buf);
319			ms->flags |= MAGIC_SYMLINK;
320			return p != NULL ? 1 : -1;
321		} else { /* just print what it points to */
322			if (mime) {
323				if (handle_mime(ms, mime, "x-symlink") == -1)
324					return -1;
325			} else if (file_printf(ms, "symbolic link to %s",
326			    buf) == -1)
327				return -1;
328		}
329		return 1;
330#endif
331#ifdef	S_IFSOCK
332#ifndef __COHERENT__
333	case S_IFSOCK:
334		if (mime) {
335			if (handle_mime(ms, mime, "x-socket") == -1)
336				return -1;
337		} else if (file_printf(ms, "socket") == -1)
338			return -1;
339		return 1;
340#endif
341#endif
342	case S_IFREG:
343		if (ms->flags & MAGIC_REGULAR) {
344			if (file_printf(ms, "regular file") == -1)
345				return -1;
346			return 1;
347		}
348		break;
349	default:
350		file_error(ms, 0, "invalid mode 0%o", sb->st_mode);
351		return -1;
352		/*NOTREACHED*/
353	}
354
355	/*
356	 * regular file, check next possibility
357	 *
358	 * If stat() tells us the file has zero length, report here that
359	 * the file is empty, so we can skip all the work of opening and
360	 * reading the file.
361	 * But if the -s option has been given, we skip this optimization,
362	 * since on some systems, stat() reports zero size for raw disk
363	 * partitions.  (If the block special device really has zero length,
364	 * the fact that it is empty will be detected and reported correctly
365	 * when we read the file.)
366	 */
367	if ((ms->flags & MAGIC_DEVICES) == 0 && sb->st_size == 0) {
368		if (mime) {
369			if (handle_mime(ms, mime, "x-empty") == -1)
370				return -1;
371		} else if (file_printf(ms, "empty") == -1)
372			return -1;
373		return 1;
374	}
375	return 0;
376}
377