xref: /freebsd/lib/libc/gen/fstab.c (revision da0878836b6c67409cb0280c86c68dbc4d28cc2f)
1 /*
2  * Copyright (c) 1980, 1988, 1993
3  *	The Regents of the University of California.  All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 4. Neither the name of the University nor the names of its contributors
14  *    may be used to endorse or promote products derived from this software
15  *    without specific prior written permission.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  */
29 
30 #if defined(LIBC_SCCS) && !defined(lint)
31 static char sccsid[] = "@(#)fstab.c	8.1 (Berkeley) 6/4/93";
32 #endif /* LIBC_SCCS and not lint */
33 #include <sys/cdefs.h>
34 __FBSDID("$FreeBSD$");
35 
36 #include "namespace.h"
37 #include <sys/param.h>
38 #include <sys/mount.h>
39 #include <sys/stat.h>
40 
41 #include <errno.h>
42 #include <fcntl.h>
43 #include <fstab.h>
44 #include <paths.h>
45 #include <stdio.h>
46 #include <stdlib.h>
47 #include <string.h>
48 #include <unistd.h>
49 #include <vis.h>
50 #include "un-namespace.h"
51 
52 static FILE *_fs_fp;
53 static struct fstab _fs_fstab;
54 static int LineNo = 0;
55 static char *path_fstab;
56 static char fstab_path[PATH_MAX];
57 static int fsp_set = 0;
58 
59 static void error(int);
60 static void fixfsfile(void);
61 static int fstabscan(void);
62 
63 void
64 setfstab(const char *file)
65 {
66 
67 	if (file == NULL) {
68 		path_fstab = _PATH_FSTAB;
69 	} else {
70 		strncpy(fstab_path, file, PATH_MAX);
71 		fstab_path[PATH_MAX - 1] = '\0';
72 		path_fstab = fstab_path;
73 	}
74 	fsp_set = 1;
75 
76 	return;
77 }
78 
79 const char *
80 getfstab(void)
81 {
82 
83 	if (fsp_set)
84 		return (path_fstab);
85 	else
86 		return (_PATH_FSTAB);
87 }
88 
89 static void
90 fixfsfile(void)
91 {
92 	static char buf[sizeof(_PATH_DEV) + MNAMELEN];
93 	struct stat sb;
94 	struct statfs sf;
95 
96 	if (_fs_fstab.fs_file != NULL && strcmp(_fs_fstab.fs_file, "/") != 0)
97 		return;
98 	if (statfs("/", &sf) != 0)
99 		return;
100 	if (sf.f_mntfromname[0] == '/')
101 		buf[0] = '\0';
102 	else
103 		strcpy(buf, _PATH_DEV);
104 	strcat(buf, sf.f_mntfromname);
105 	if (stat(buf, &sb) != 0 ||
106 	    (!S_ISBLK(sb.st_mode) && !S_ISCHR(sb.st_mode)))
107 		return;
108 	_fs_fstab.fs_spec = buf;
109 }
110 
111 static int
112 fstabscan(void)
113 {
114 	char *cp, *p;
115 #define	MAXLINELENGTH	1024
116 	static char line[MAXLINELENGTH];
117 	char subline[MAXLINELENGTH];
118 	int typexx;
119 
120 	for (;;) {
121 
122 		if (!(p = fgets(line, sizeof(line), _fs_fp)))
123 			return (0);
124 /* OLD_STYLE_FSTAB */
125 		++LineNo;
126 		if (*line == '#' || *line == '\n')
127 			continue;
128 		if (!strpbrk(p, " \t")) {
129 			_fs_fstab.fs_spec = strsep(&p, ":\n");
130 			_fs_fstab.fs_file = strsep(&p, ":\n");
131 			fixfsfile();
132 			_fs_fstab.fs_type = strsep(&p, ":\n");
133 			if (_fs_fstab.fs_type) {
134 				if (!strcmp(_fs_fstab.fs_type, FSTAB_XX))
135 					continue;
136 				_fs_fstab.fs_mntops = _fs_fstab.fs_type;
137 				_fs_fstab.fs_vfstype =
138 				    strcmp(_fs_fstab.fs_type, FSTAB_SW) ?
139 				    "ufs" : "swap";
140 				if ((cp = strsep(&p, ":\n")) != NULL) {
141 					_fs_fstab.fs_freq = atoi(cp);
142 					if ((cp = strsep(&p, ":\n")) != NULL) {
143 						_fs_fstab.fs_passno = atoi(cp);
144 						return (1);
145 					}
146 				}
147 			}
148 			goto bad;
149 		}
150 /* OLD_STYLE_FSTAB */
151 		while ((cp = strsep(&p, " \t\n")) != NULL && *cp == '\0')
152 			;
153 		if (strunvis(cp, cp) < 0)
154 			goto bad;
155 		_fs_fstab.fs_spec = cp;
156 		if (!_fs_fstab.fs_spec || *_fs_fstab.fs_spec == '#')
157 			continue;
158 		while ((cp = strsep(&p, " \t\n")) != NULL && *cp == '\0')
159 			;
160 		if (strunvis(cp, cp) < 0)
161 			goto bad;
162 		_fs_fstab.fs_file = cp;
163 		fixfsfile();
164 		while ((cp = strsep(&p, " \t\n")) != NULL && *cp == '\0')
165 			;
166 		_fs_fstab.fs_vfstype = cp;
167 		while ((cp = strsep(&p, " \t\n")) != NULL && *cp == '\0')
168 			;
169 		_fs_fstab.fs_mntops = cp;
170 		if (_fs_fstab.fs_mntops == NULL)
171 			goto bad;
172 		_fs_fstab.fs_freq = 0;
173 		_fs_fstab.fs_passno = 0;
174 		while ((cp = strsep(&p, " \t\n")) != NULL && *cp == '\0')
175 			;
176 		if (cp != NULL) {
177 			_fs_fstab.fs_freq = atoi(cp);
178 			while ((cp = strsep(&p, " \t\n")) != NULL && *cp == '\0')
179 				;
180 			if (cp != NULL)
181 				_fs_fstab.fs_passno = atoi(cp);
182 		}
183 		strcpy(subline, _fs_fstab.fs_mntops);
184 		p = subline;
185 		for (typexx = 0, cp = strsep(&p, ","); cp;
186 		     cp = strsep(&p, ",")) {
187 			if (strlen(cp) != 2)
188 				continue;
189 			if (!strcmp(cp, FSTAB_RW)) {
190 				_fs_fstab.fs_type = FSTAB_RW;
191 				break;
192 			}
193 			if (!strcmp(cp, FSTAB_RQ)) {
194 				_fs_fstab.fs_type = FSTAB_RQ;
195 				break;
196 			}
197 			if (!strcmp(cp, FSTAB_RO)) {
198 				_fs_fstab.fs_type = FSTAB_RO;
199 				break;
200 			}
201 			if (!strcmp(cp, FSTAB_SW)) {
202 				_fs_fstab.fs_type = FSTAB_SW;
203 				break;
204 			}
205 			if (!strcmp(cp, FSTAB_XX)) {
206 				_fs_fstab.fs_type = FSTAB_XX;
207 				typexx++;
208 				break;
209 			}
210 		}
211 		if (typexx)
212 			continue;
213 		if (cp != NULL)
214 			return (1);
215 
216 bad:		/* no way to distinguish between EOF and syntax error */
217 		error(EFTYPE);
218 	}
219 	/* NOTREACHED */
220 }
221 
222 struct fstab *
223 getfsent(void)
224 {
225 
226 	if ((!_fs_fp && !setfsent()) || !fstabscan())
227 		return (NULL);
228 	return (&_fs_fstab);
229 }
230 
231 struct fstab *
232 getfsspec(const char *name)
233 {
234 
235 	if (setfsent())
236 		while (fstabscan())
237 			if (!strcmp(_fs_fstab.fs_spec, name))
238 				return (&_fs_fstab);
239 	return (NULL);
240 }
241 
242 struct fstab *
243 getfsfile(const char *name)
244 {
245 
246 	if (setfsent())
247 		while (fstabscan())
248 			if (!strcmp(_fs_fstab.fs_file, name))
249 				return (&_fs_fstab);
250 	return (NULL);
251 }
252 
253 int
254 setfsent(void)
255 {
256 	int fd;
257 
258 	if (_fs_fp) {
259 		rewind(_fs_fp);
260 		LineNo = 0;
261 		return (1);
262 	}
263 	if (fsp_set == 0) {
264 		if (issetugid())
265 			setfstab(NULL);
266 		else
267 			setfstab(getenv("PATH_FSTAB"));
268 	}
269 	fd = _open(path_fstab, O_RDONLY | O_CLOEXEC);
270 	if (fd == -1) {
271 		error(errno);
272 		return (0);
273 	}
274 	_fs_fp = fdopen(fd, "r");
275 	if (_fs_fp  != NULL) {
276 		LineNo = 0;
277 		return (1);
278 	}
279 	error(errno);
280 	_close(fd);
281 	return (0);
282 }
283 
284 void
285 endfsent(void)
286 {
287 
288 	if (_fs_fp) {
289 		(void)fclose(_fs_fp);
290 		_fs_fp = NULL;
291 	}
292 
293 	fsp_set = 0;
294 }
295 
296 static void
297 error(int err)
298 {
299 	char *p;
300 	char num[30];
301 
302 	(void)_write(STDERR_FILENO, "fstab: ", 7);
303 	(void)_write(STDERR_FILENO, path_fstab, strlen(path_fstab));
304 	(void)_write(STDERR_FILENO, ":", 1);
305 	sprintf(num, "%d: ", LineNo);
306 	(void)_write(STDERR_FILENO, num, strlen(num));
307 	p = strerror(err);
308 	(void)_write(STDERR_FILENO, p, strlen(p));
309 	(void)_write(STDERR_FILENO, "\n", 1);
310 }
311