xref: /freebsd/sbin/mount/getmntopts.c (revision a2f733abcff64628b7771a47089628b7327a88bd)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1994
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 0
33 #endif
34 #include <sys/cdefs.h>
35 #include <sys/param.h>
36 #include <sys/mount.h>
37 #include <sys/stat.h>
38 #include <sys/uio.h>
39 
40 #include <err.h>
41 #include <errno.h>
42 #include <paths.h>
43 #include <stdarg.h>
44 #include <stdio.h>
45 #include <stdlib.h>
46 #include <string.h>
47 
48 #include "mntopts.h"
49 
50 int getmnt_silent = 0;
51 
52 void
53 getmntopts(const char *options, const struct mntopt *m0, int *flagp,
54 	int *altflagp)
55 {
56 	const struct mntopt *m;
57 	int negative, len;
58 	char *opt, *optbuf, *p;
59 	int *thisflagp;
60 
61 	/* Copy option string, since it is about to be torn asunder... */
62 	if ((optbuf = strdup(options)) == NULL)
63 		err(1, NULL);
64 
65 	for (opt = optbuf; (opt = strtok(opt, ",")) != NULL; opt = NULL) {
66 		/* Check for "no" prefix. */
67 		if (opt[0] == 'n' && opt[1] == 'o') {
68 			negative = 1;
69 			opt += 2;
70 		} else
71 			negative = 0;
72 
73 		/*
74 		 * for options with assignments in them (ie. quotas)
75 		 * ignore the assignment as it's handled elsewhere
76 		 */
77 		p = strchr(opt, '=');
78 		if (p != NULL)
79 			 *++p = '\0';
80 
81 		/* Scan option table. */
82 		for (m = m0; m->m_option != NULL; ++m) {
83 			len = strlen(m->m_option);
84 			if (strncasecmp(opt, m->m_option, len) == 0)
85 				if (opt[len] == '\0' || opt[len] == '=')
86 					break;
87 		}
88 
89 		/* Save flag, or fail if option is not recognized. */
90 		if (m->m_option) {
91 			thisflagp = m->m_altloc ? altflagp : flagp;
92 			if (negative == m->m_inverse)
93 				*thisflagp |= m->m_flag;
94 			else
95 				*thisflagp &= ~m->m_flag;
96 		} else if (!getmnt_silent) {
97 			errx(1, "-o %s: option not supported", opt);
98 		}
99 	}
100 
101 	free(optbuf);
102 }
103 
104 void
105 rmslashes(char *rrpin, char *rrpout)
106 {
107 	char *rrpoutstart;
108 
109 	*rrpout = *rrpin;
110 	for (rrpoutstart = rrpout; *rrpin != '\0'; *rrpout++ = *rrpin++) {
111 
112 		/* skip all double slashes */
113 		while (*rrpin == '/' && *(rrpin + 1) == '/')
114 			 rrpin++;
115 	}
116 
117 	/* remove trailing slash if necessary */
118 	if (rrpout - rrpoutstart > 1 && *(rrpout - 1) == '/')
119 		*(rrpout - 1) = '\0';
120 	else
121 		*rrpout = '\0';
122 }
123 
124 int
125 checkpath(const char *path, char *resolved)
126 {
127 	struct stat sb;
128 
129 	if (realpath(path, resolved) == NULL || stat(resolved, &sb) != 0)
130 		return (1);
131 	if (!S_ISDIR(sb.st_mode)) {
132 		errno = ENOTDIR;
133 		return (1);
134 	}
135 	return (0);
136 }
137 
138 int
139 checkpath_allow_file(const char *path, char *resolved)
140 {
141 	struct stat sb;
142 
143 	if (realpath(path, resolved) == NULL || stat(resolved, &sb) != 0)
144 		return (1);
145 	if (!S_ISDIR(sb.st_mode) && !S_ISREG(sb.st_mode)) {
146 		errno = ENOTDIR;
147 		return (1);
148 	}
149 	return (0);
150 }
151 
152 /*
153  * Get the mount point information for name. Name may be mount point name
154  * or device name (with or without /dev/ preprended).
155  */
156 struct statfs *
157 getmntpoint(const char *name)
158 {
159 	struct stat devstat, mntdevstat;
160 	char device[sizeof(_PATH_DEV) - 1 + MNAMELEN];
161 	char *ddevname;
162 	struct statfs *mntbuf, *statfsp;
163 	int i, mntsize, isdev;
164 	u_long len;
165 
166 	if (stat(name, &devstat) != 0)
167 		return (NULL);
168 	if (S_ISCHR(devstat.st_mode) || S_ISBLK(devstat.st_mode))
169 		isdev = 1;
170 	else
171 		isdev = 0;
172 	mntsize = getmntinfo(&mntbuf, MNT_NOWAIT);
173 	for (i = 0; i < mntsize; i++) {
174 		statfsp = &mntbuf[i];
175 		if (isdev == 0) {
176 			if (strcmp(name, statfsp->f_mntonname))
177 				continue;
178 			return (statfsp);
179 		}
180 		ddevname = statfsp->f_mntfromname;
181 		if (*ddevname != '/') {
182 			if ((len = strlen(_PATH_DEV) + strlen(ddevname) + 1) >
183 			    sizeof(statfsp->f_mntfromname) ||
184 			    len > sizeof(device))
185 				continue;
186 			strncpy(device, _PATH_DEV, len);
187 			strncat(device, ddevname, len);
188 			if (stat(device, &mntdevstat) == 0)
189 				strncpy(statfsp->f_mntfromname, device, len);
190 		}
191 		if (stat(ddevname, &mntdevstat) == 0 &&
192 		    mntdevstat.st_rdev == devstat.st_rdev)
193 			return (statfsp);
194 	}
195 	return (NULL);
196 }
197 
198 /*
199  * If possible reload a mounted filesystem.
200  * When prtmsg != NULL print a warning if a reload is attempted, but fails.
201  * Return 0 on success, 1 on failure.
202  */
203 int
204 chkdoreload(struct statfs *mntp,
205 	void (*prtmsg)(const char *, ...) __printflike(1,2))
206 {
207 	struct iovec *iov;
208 	int iovlen, error;
209 	char errmsg[255];
210 
211 	/*
212 	 * If the filesystem is not mounted it does not need to be reloaded.
213 	 * If it is mounted for writing, then it could not have been opened
214 	 * for writing by a utility, so does not need to be reloaded.
215 	 */
216 	if (mntp == NULL || (mntp->f_flags & MNT_RDONLY) == 0)
217 		return (0);
218 
219 	/*
220 	 * We modified a mounted file system.  Do a mount update on
221 	 * it so we can continue using it as safely as possible.
222 	 */
223 	iov = NULL;
224 	iovlen = 0;
225 	errmsg[0] = '\0';
226 	build_iovec(&iov, &iovlen, "fstype", __DECONST(void *, "ffs"), 4);
227 	build_iovec(&iov, &iovlen, "from", mntp->f_mntfromname, (size_t)-1);
228 	build_iovec(&iov, &iovlen, "fspath", mntp->f_mntonname, (size_t)-1);
229 	build_iovec(&iov, &iovlen, "errmsg", errmsg, sizeof(errmsg));
230 	build_iovec(&iov, &iovlen, "update", NULL, 0);
231 	build_iovec(&iov, &iovlen, "reload", NULL, 0);
232 	/*
233 	 * XX: We need the following line until we clean up
234 	 * nmount parsing of root mounts and NFS root mounts.
235 	 */
236 	build_iovec(&iov, &iovlen, "ro", NULL, 0);
237 	error = nmount(iov, iovlen, mntp->f_flags);
238 	free_iovec(&iov, &iovlen);
239 	if (error == 0)
240 		return (0);
241 	if (prtmsg != NULL)
242 		prtmsg("mount reload of '%s' failed: %s %s\n\n",
243 		    mntp->f_mntonname, strerror(errno), errmsg);
244 	return (1);
245 }
246 
247 void
248 build_iovec(struct iovec **iov, int *iovlen, const char *name, void *val,
249 	    size_t len)
250 {
251 	int i;
252 
253 	if (*iovlen < 0)
254 		return;
255 	i = *iovlen;
256 	*iov = realloc(*iov, sizeof **iov * (i + 2));
257 	if (*iov == NULL) {
258 		*iovlen = -1;
259 		return;
260 	}
261 	(*iov)[i].iov_base = strdup(name);
262 	(*iov)[i].iov_len = strlen(name) + 1;
263 	i++;
264 	(*iov)[i].iov_base = val;
265 	if (len == (size_t)-1) {
266 		if (val != NULL)
267 			len = strlen(val) + 1;
268 		else
269 			len = 0;
270 	}
271 	(*iov)[i].iov_len = (int)len;
272 	*iovlen = ++i;
273 }
274 
275 /*
276  * This function is needed for compatibility with parameters
277  * which used to use the mount_argf() command for the old mount() syscall.
278  */
279 void
280 build_iovec_argf(struct iovec **iov, int *iovlen, const char *name,
281     const char *fmt, ...)
282 {
283 	va_list ap;
284 	char val[255] = { 0 };
285 
286 	va_start(ap, fmt);
287 	vsnprintf(val, sizeof(val), fmt, ap);
288 	va_end(ap);
289 	build_iovec(iov, iovlen, name, strdup(val), (size_t)-1);
290 }
291 
292 /*
293  * Free the iovec and reset to NULL with zero length.  Useful for calling
294  * nmount in a loop.
295  */
296 void
297 free_iovec(struct iovec **iov, int *iovlen)
298 {
299 	int i;
300 
301 	for (i = 0; i < *iovlen; i += 2)
302 		free((*iov)[i].iov_base);
303 	free(*iov);
304 }
305