xref: /freebsd/lib/libc/gen/fstab.c (revision 8ddb146abcdf061be9f2c0db7e391697dafad85c)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1980, 1988, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, 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  * 3. Neither the name of the University nor the names of its contributors
16  *    may be used to endorse or promote products derived from this software
17  *    without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  */
31 
32 #include <sys/cdefs.h>
33 __SCCSID("@(#)fstab.c	8.1 (Berkeley) 6/4/93");
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 <fstab.h>
43 #include <paths.h>
44 #include <stdio.h>
45 #include <stdlib.h>
46 #include <string.h>
47 #include <unistd.h>
48 #include <vis.h>
49 #include "un-namespace.h"
50 
51 static FILE *_fs_fp;
52 static struct fstab _fs_fstab;
53 static int LineNo = 0;
54 static char *path_fstab;
55 static char fstab_path[PATH_MAX];
56 static int fsp_set = 0;
57 
58 static void error(int);
59 static void fixfsfile(void);
60 static int fstabscan(void);
61 
62 void
63 setfstab(const char *file)
64 {
65 
66 	if (file == NULL) {
67 		path_fstab = _PATH_FSTAB;
68 	} else {
69 		strncpy(fstab_path, file, PATH_MAX);
70 		fstab_path[PATH_MAX - 1] = '\0';
71 		path_fstab = fstab_path;
72 	}
73 	fsp_set = 1;
74 
75 	return;
76 }
77 
78 const char *
79 getfstab(void)
80 {
81 
82 	if (fsp_set)
83 		return (path_fstab);
84 	else
85 		return (_PATH_FSTAB);
86 }
87 
88 static void
89 fixfsfile(void)
90 {
91 	static char buf[sizeof(_PATH_DEV) + MNAMELEN];
92 	struct stat sb;
93 	struct statfs sf;
94 
95 	if (_fs_fstab.fs_file != NULL && strcmp(_fs_fstab.fs_file, "/") != 0)
96 		return;
97 	if (statfs("/", &sf) != 0)
98 		return;
99 	if (sf.f_mntfromname[0] == '/')
100 		buf[0] = '\0';
101 	else
102 		strcpy(buf, _PATH_DEV);
103 	strcat(buf, sf.f_mntfromname);
104 	if (stat(buf, &sb) != 0 ||
105 	    (!S_ISBLK(sb.st_mode) && !S_ISCHR(sb.st_mode)))
106 		return;
107 	_fs_fstab.fs_spec = buf;
108 }
109 
110 static int
111 fstabscan(void)
112 {
113 	char *cp, *p;
114 #define	MAXLINELENGTH	1024
115 	static char line[MAXLINELENGTH];
116 	char subline[MAXLINELENGTH];
117 	int typexx;
118 
119 	for (;;) {
120 
121 		if (!(p = fgets(line, sizeof(line), _fs_fp)))
122 			return (0);
123 /* OLD_STYLE_FSTAB */
124 		++LineNo;
125 		if (*line == '#' || *line == '\n')
126 			continue;
127 		if (!strpbrk(p, " \t")) {
128 			_fs_fstab.fs_spec = strsep(&p, ":\n");
129 			_fs_fstab.fs_file = strsep(&p, ":\n");
130 			fixfsfile();
131 			_fs_fstab.fs_type = strsep(&p, ":\n");
132 			if (_fs_fstab.fs_type) {
133 				if (!strcmp(_fs_fstab.fs_type, FSTAB_XX))
134 					continue;
135 				_fs_fstab.fs_mntops = _fs_fstab.fs_type;
136 				_fs_fstab.fs_vfstype =
137 				    strcmp(_fs_fstab.fs_type, FSTAB_SW) ?
138 				    "ufs" : "swap";
139 				if ((cp = strsep(&p, ":\n")) != NULL) {
140 					_fs_fstab.fs_freq = atoi(cp);
141 					if ((cp = strsep(&p, ":\n")) != NULL) {
142 						_fs_fstab.fs_passno = atoi(cp);
143 						return (1);
144 					}
145 				}
146 			}
147 			goto bad;
148 		}
149 /* OLD_STYLE_FSTAB */
150 		while ((cp = strsep(&p, " \t\n")) != NULL && *cp == '\0')
151 			;
152 		_fs_fstab.fs_spec = cp;
153 		if (_fs_fstab.fs_spec == NULL || *_fs_fstab.fs_spec == '#')
154 			continue;
155 		if (strunvis(_fs_fstab.fs_spec, _fs_fstab.fs_spec) < 0)
156 			goto bad;
157 		while ((cp = strsep(&p, " \t\n")) != NULL && *cp == '\0')
158 			;
159 		_fs_fstab.fs_file = cp;
160 		if (_fs_fstab.fs_file == NULL)
161 			goto bad;
162 		if (strunvis(_fs_fstab.fs_file, _fs_fstab.fs_file) < 0)
163 			goto bad;
164 		fixfsfile();
165 		while ((cp = strsep(&p, " \t\n")) != NULL && *cp == '\0')
166 			;
167 		_fs_fstab.fs_vfstype = cp;
168 		while ((cp = strsep(&p, " \t\n")) != NULL && *cp == '\0')
169 			;
170 		_fs_fstab.fs_mntops = cp;
171 		if (_fs_fstab.fs_mntops == NULL)
172 			goto bad;
173 		_fs_fstab.fs_freq = 0;
174 		_fs_fstab.fs_passno = 0;
175 		while ((cp = strsep(&p, " \t\n")) != NULL && *cp == '\0')
176 			;
177 		if (cp != NULL) {
178 			_fs_fstab.fs_freq = atoi(cp);
179 			while ((cp = strsep(&p, " \t\n")) != NULL && *cp == '\0')
180 				;
181 			if (cp != NULL)
182 				_fs_fstab.fs_passno = atoi(cp);
183 		}
184 		(void)strlcpy(subline, _fs_fstab.fs_mntops, sizeof(subline));
185 		p = subline;
186 		for (typexx = 0, cp = strsep(&p, ","); cp;
187 		     cp = strsep(&p, ",")) {
188 			if (strlen(cp) != 2)
189 				continue;
190 			if (!strcmp(cp, FSTAB_RW)) {
191 				_fs_fstab.fs_type = FSTAB_RW;
192 				break;
193 			}
194 			if (!strcmp(cp, FSTAB_RQ)) {
195 				_fs_fstab.fs_type = FSTAB_RQ;
196 				break;
197 			}
198 			if (!strcmp(cp, FSTAB_RO)) {
199 				_fs_fstab.fs_type = FSTAB_RO;
200 				break;
201 			}
202 			if (!strcmp(cp, FSTAB_SW)) {
203 				_fs_fstab.fs_type = FSTAB_SW;
204 				break;
205 			}
206 			if (!strcmp(cp, FSTAB_XX)) {
207 				_fs_fstab.fs_type = FSTAB_XX;
208 				typexx++;
209 				break;
210 			}
211 		}
212 		if (typexx)
213 			continue;
214 		if (cp != NULL)
215 			return (1);
216 
217 bad:		/* no way to distinguish between EOF and syntax error */
218 		error(EFTYPE);
219 	}
220 	/* NOTREACHED */
221 }
222 
223 struct fstab *
224 getfsent(void)
225 {
226 
227 	if ((!_fs_fp && !setfsent()) || !fstabscan())
228 		return (NULL);
229 	return (&_fs_fstab);
230 }
231 
232 struct fstab *
233 getfsspec(const char *name)
234 {
235 
236 	if (setfsent())
237 		while (fstabscan())
238 			if (!strcmp(_fs_fstab.fs_spec, name))
239 				return (&_fs_fstab);
240 	return (NULL);
241 }
242 
243 struct fstab *
244 getfsfile(const char *name)
245 {
246 
247 	if (setfsent())
248 		while (fstabscan())
249 			if (!strcmp(_fs_fstab.fs_file, name))
250 				return (&_fs_fstab);
251 	return (NULL);
252 }
253 
254 int
255 setfsent(void)
256 {
257 	if (_fs_fp) {
258 		rewind(_fs_fp);
259 		LineNo = 0;
260 		return (1);
261 	}
262 	if (fsp_set == 0) {
263 		if (issetugid())
264 			setfstab(NULL);
265 		else
266 			setfstab(getenv("PATH_FSTAB"));
267 	}
268 	if ((_fs_fp = fopen(path_fstab, "re")) != NULL) {
269 		LineNo = 0;
270 		return (1);
271 	}
272 	error(errno);
273 	return (0);
274 }
275 
276 void
277 endfsent(void)
278 {
279 
280 	if (_fs_fp) {
281 		(void)fclose(_fs_fp);
282 		_fs_fp = NULL;
283 	}
284 
285 	fsp_set = 0;
286 }
287 
288 static void
289 error(int err)
290 {
291 	char *p;
292 	char num[30];
293 
294 	(void)_write(STDERR_FILENO, "fstab: ", 7);
295 	(void)_write(STDERR_FILENO, path_fstab, strlen(path_fstab));
296 	(void)_write(STDERR_FILENO, ":", 1);
297 	sprintf(num, "%d: ", LineNo);
298 	(void)_write(STDERR_FILENO, num, strlen(num));
299 	p = strerror(err);
300 	(void)_write(STDERR_FILENO, p, strlen(p));
301 	(void)_write(STDERR_FILENO, "\n", 1);
302 }
303