xref: /freebsd/lib/libc/gen/fstab.c (revision 74fe6c29fb7eef3418d7919dcd41dc1a04a982a1)
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 #if defined(LIBC_SCCS) && !defined(lint)
33 static char sccsid[] = "@(#)fstab.c	8.1 (Berkeley) 6/4/93";
34 #endif /* LIBC_SCCS and not lint */
35 #include <sys/cdefs.h>
36 __FBSDID("$FreeBSD$");
37 
38 #include "namespace.h"
39 #include <sys/param.h>
40 #include <sys/mount.h>
41 #include <sys/stat.h>
42 
43 #include <errno.h>
44 #include <fstab.h>
45 #include <paths.h>
46 #include <stdio.h>
47 #include <stdlib.h>
48 #include <string.h>
49 #include <unistd.h>
50 #include <vis.h>
51 #include "un-namespace.h"
52 
53 static FILE *_fs_fp;
54 static struct fstab _fs_fstab;
55 static int LineNo = 0;
56 static char *path_fstab;
57 static char fstab_path[PATH_MAX];
58 static int fsp_set = 0;
59 
60 static void error(int);
61 static void fixfsfile(void);
62 static int fstabscan(void);
63 
64 void
65 setfstab(const char *file)
66 {
67 
68 	if (file == NULL) {
69 		path_fstab = _PATH_FSTAB;
70 	} else {
71 		strncpy(fstab_path, file, PATH_MAX);
72 		fstab_path[PATH_MAX - 1] = '\0';
73 		path_fstab = fstab_path;
74 	}
75 	fsp_set = 1;
76 
77 	return;
78 }
79 
80 const char *
81 getfstab(void)
82 {
83 
84 	if (fsp_set)
85 		return (path_fstab);
86 	else
87 		return (_PATH_FSTAB);
88 }
89 
90 static void
91 fixfsfile(void)
92 {
93 	static char buf[sizeof(_PATH_DEV) + MNAMELEN];
94 	struct stat sb;
95 	struct statfs sf;
96 
97 	if (_fs_fstab.fs_file != NULL && strcmp(_fs_fstab.fs_file, "/") != 0)
98 		return;
99 	if (statfs("/", &sf) != 0)
100 		return;
101 	if (sf.f_mntfromname[0] == '/')
102 		buf[0] = '\0';
103 	else
104 		strcpy(buf, _PATH_DEV);
105 	strcat(buf, sf.f_mntfromname);
106 	if (stat(buf, &sb) != 0 ||
107 	    (!S_ISBLK(sb.st_mode) && !S_ISCHR(sb.st_mode)))
108 		return;
109 	_fs_fstab.fs_spec = buf;
110 }
111 
112 static int
113 fstabscan(void)
114 {
115 	char *cp, *p;
116 #define	MAXLINELENGTH	1024
117 	static char line[MAXLINELENGTH];
118 	char subline[MAXLINELENGTH];
119 	int typexx;
120 
121 	for (;;) {
122 
123 		if (!(p = fgets(line, sizeof(line), _fs_fp)))
124 			return (0);
125 /* OLD_STYLE_FSTAB */
126 		++LineNo;
127 		if (*line == '#' || *line == '\n')
128 			continue;
129 		if (!strpbrk(p, " \t")) {
130 			_fs_fstab.fs_spec = strsep(&p, ":\n");
131 			_fs_fstab.fs_file = strsep(&p, ":\n");
132 			fixfsfile();
133 			_fs_fstab.fs_type = strsep(&p, ":\n");
134 			if (_fs_fstab.fs_type) {
135 				if (!strcmp(_fs_fstab.fs_type, FSTAB_XX))
136 					continue;
137 				_fs_fstab.fs_mntops = _fs_fstab.fs_type;
138 				_fs_fstab.fs_vfstype =
139 				    strcmp(_fs_fstab.fs_type, FSTAB_SW) ?
140 				    "ufs" : "swap";
141 				if ((cp = strsep(&p, ":\n")) != NULL) {
142 					_fs_fstab.fs_freq = atoi(cp);
143 					if ((cp = strsep(&p, ":\n")) != NULL) {
144 						_fs_fstab.fs_passno = atoi(cp);
145 						return (1);
146 					}
147 				}
148 			}
149 			goto bad;
150 		}
151 /* OLD_STYLE_FSTAB */
152 		while ((cp = strsep(&p, " \t\n")) != NULL && *cp == '\0')
153 			;
154 		_fs_fstab.fs_spec = cp;
155 		if (_fs_fstab.fs_spec == NULL || *_fs_fstab.fs_spec == '#')
156 			continue;
157 		if (strunvis(_fs_fstab.fs_spec, _fs_fstab.fs_spec) < 0)
158 			goto bad;
159 		while ((cp = strsep(&p, " \t\n")) != NULL && *cp == '\0')
160 			;
161 		_fs_fstab.fs_file = cp;
162 		if (_fs_fstab.fs_file == NULL)
163 			goto bad;
164 		if (strunvis(_fs_fstab.fs_file, _fs_fstab.fs_file) < 0)
165 			goto bad;
166 		fixfsfile();
167 		while ((cp = strsep(&p, " \t\n")) != NULL && *cp == '\0')
168 			;
169 		_fs_fstab.fs_vfstype = cp;
170 		while ((cp = strsep(&p, " \t\n")) != NULL && *cp == '\0')
171 			;
172 		_fs_fstab.fs_mntops = cp;
173 		if (_fs_fstab.fs_mntops == NULL)
174 			goto bad;
175 		_fs_fstab.fs_freq = 0;
176 		_fs_fstab.fs_passno = 0;
177 		while ((cp = strsep(&p, " \t\n")) != NULL && *cp == '\0')
178 			;
179 		if (cp != NULL) {
180 			_fs_fstab.fs_freq = atoi(cp);
181 			while ((cp = strsep(&p, " \t\n")) != NULL && *cp == '\0')
182 				;
183 			if (cp != NULL)
184 				_fs_fstab.fs_passno = atoi(cp);
185 		}
186 		(void)strlcpy(subline, _fs_fstab.fs_mntops, sizeof(subline));
187 		p = subline;
188 		for (typexx = 0, cp = strsep(&p, ","); cp;
189 		     cp = strsep(&p, ",")) {
190 			if (strlen(cp) != 2)
191 				continue;
192 			if (!strcmp(cp, FSTAB_RW)) {
193 				_fs_fstab.fs_type = FSTAB_RW;
194 				break;
195 			}
196 			if (!strcmp(cp, FSTAB_RQ)) {
197 				_fs_fstab.fs_type = FSTAB_RQ;
198 				break;
199 			}
200 			if (!strcmp(cp, FSTAB_RO)) {
201 				_fs_fstab.fs_type = FSTAB_RO;
202 				break;
203 			}
204 			if (!strcmp(cp, FSTAB_SW)) {
205 				_fs_fstab.fs_type = FSTAB_SW;
206 				break;
207 			}
208 			if (!strcmp(cp, FSTAB_XX)) {
209 				_fs_fstab.fs_type = FSTAB_XX;
210 				typexx++;
211 				break;
212 			}
213 		}
214 		if (typexx)
215 			continue;
216 		if (cp != NULL)
217 			return (1);
218 
219 bad:		/* no way to distinguish between EOF and syntax error */
220 		error(EFTYPE);
221 	}
222 	/* NOTREACHED */
223 }
224 
225 struct fstab *
226 getfsent(void)
227 {
228 
229 	if ((!_fs_fp && !setfsent()) || !fstabscan())
230 		return (NULL);
231 	return (&_fs_fstab);
232 }
233 
234 struct fstab *
235 getfsspec(const char *name)
236 {
237 
238 	if (setfsent())
239 		while (fstabscan())
240 			if (!strcmp(_fs_fstab.fs_spec, name))
241 				return (&_fs_fstab);
242 	return (NULL);
243 }
244 
245 struct fstab *
246 getfsfile(const char *name)
247 {
248 
249 	if (setfsent())
250 		while (fstabscan())
251 			if (!strcmp(_fs_fstab.fs_file, name))
252 				return (&_fs_fstab);
253 	return (NULL);
254 }
255 
256 int
257 setfsent(void)
258 {
259 	if (_fs_fp) {
260 		rewind(_fs_fp);
261 		LineNo = 0;
262 		return (1);
263 	}
264 	if (fsp_set == 0) {
265 		if (issetugid())
266 			setfstab(NULL);
267 		else
268 			setfstab(getenv("PATH_FSTAB"));
269 	}
270 	if ((_fs_fp = fopen(path_fstab, "re")) != NULL) {
271 		LineNo = 0;
272 		return (1);
273 	}
274 	error(errno);
275 	return (0);
276 }
277 
278 void
279 endfsent(void)
280 {
281 
282 	if (_fs_fp) {
283 		(void)fclose(_fs_fp);
284 		_fs_fp = NULL;
285 	}
286 
287 	fsp_set = 0;
288 }
289 
290 static void
291 error(int err)
292 {
293 	char *p;
294 	char num[30];
295 
296 	(void)_write(STDERR_FILENO, "fstab: ", 7);
297 	(void)_write(STDERR_FILENO, path_fstab, strlen(path_fstab));
298 	(void)_write(STDERR_FILENO, ":", 1);
299 	sprintf(num, "%d: ", LineNo);
300 	(void)_write(STDERR_FILENO, num, strlen(num));
301 	p = strerror(err);
302 	(void)_write(STDERR_FILENO, p, strlen(p));
303 	(void)_write(STDERR_FILENO, "\n", 1);
304 }
305