xref: /freebsd/sbin/mount/getmntopts.c (revision 1d386b48a555f61cb7325543adbbb5c3f3407a66)
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 #ifndef lint
34 static char sccsid[] = "@(#)getmntopts.c	8.3 (Berkeley) 3/29/95";
35 #endif /* not lint */
36 #endif
37 #include <sys/cdefs.h>
38 #include <sys/param.h>
39 #include <sys/mount.h>
40 #include <sys/stat.h>
41 #include <sys/uio.h>
42 
43 #include <err.h>
44 #include <errno.h>
45 #include <paths.h>
46 #include <stdarg.h>
47 #include <stdio.h>
48 #include <stdlib.h>
49 #include <string.h>
50 
51 #include "mntopts.h"
52 
53 int getmnt_silent = 0;
54 
55 void
56 getmntopts(const char *options, const struct mntopt *m0, int *flagp,
57 	int *altflagp)
58 {
59 	const struct mntopt *m;
60 	int negative, len;
61 	char *opt, *optbuf, *p;
62 	int *thisflagp;
63 
64 	/* Copy option string, since it is about to be torn asunder... */
65 	if ((optbuf = strdup(options)) == NULL)
66 		err(1, NULL);
67 
68 	for (opt = optbuf; (opt = strtok(opt, ",")) != NULL; opt = NULL) {
69 		/* Check for "no" prefix. */
70 		if (opt[0] == 'n' && opt[1] == 'o') {
71 			negative = 1;
72 			opt += 2;
73 		} else
74 			negative = 0;
75 
76 		/*
77 		 * for options with assignments in them (ie. quotas)
78 		 * ignore the assignment as it's handled elsewhere
79 		 */
80 		p = strchr(opt, '=');
81 		if (p != NULL)
82 			 *++p = '\0';
83 
84 		/* Scan option table. */
85 		for (m = m0; m->m_option != NULL; ++m) {
86 			len = strlen(m->m_option);
87 			if (strncasecmp(opt, m->m_option, len) == 0)
88 				if (opt[len] == '\0' || opt[len] == '=')
89 					break;
90 		}
91 
92 		/* Save flag, or fail if option is not recognized. */
93 		if (m->m_option) {
94 			thisflagp = m->m_altloc ? altflagp : flagp;
95 			if (negative == m->m_inverse)
96 				*thisflagp |= m->m_flag;
97 			else
98 				*thisflagp &= ~m->m_flag;
99 		} else if (!getmnt_silent) {
100 			errx(1, "-o %s: option not supported", opt);
101 		}
102 	}
103 
104 	free(optbuf);
105 }
106 
107 void
108 rmslashes(char *rrpin, char *rrpout)
109 {
110 	char *rrpoutstart;
111 
112 	*rrpout = *rrpin;
113 	for (rrpoutstart = rrpout; *rrpin != '\0'; *rrpout++ = *rrpin++) {
114 
115 		/* skip all double slashes */
116 		while (*rrpin == '/' && *(rrpin + 1) == '/')
117 			 rrpin++;
118 	}
119 
120 	/* remove trailing slash if necessary */
121 	if (rrpout - rrpoutstart > 1 && *(rrpout - 1) == '/')
122 		*(rrpout - 1) = '\0';
123 	else
124 		*rrpout = '\0';
125 }
126 
127 int
128 checkpath(const char *path, char *resolved)
129 {
130 	struct stat sb;
131 
132 	if (realpath(path, resolved) == NULL || stat(resolved, &sb) != 0)
133 		return (1);
134 	if (!S_ISDIR(sb.st_mode)) {
135 		errno = ENOTDIR;
136 		return (1);
137 	}
138 	return (0);
139 }
140 
141 int
142 checkpath_allow_file(const char *path, char *resolved)
143 {
144 	struct stat sb;
145 
146 	if (realpath(path, resolved) == NULL || stat(resolved, &sb) != 0)
147 		return (1);
148 	if (!S_ISDIR(sb.st_mode) && !S_ISREG(sb.st_mode)) {
149 		errno = ENOTDIR;
150 		return (1);
151 	}
152 	return (0);
153 }
154 
155 /*
156  * Get the mount point information for name. Name may be mount point name
157  * or device name (with or without /dev/ preprended).
158  */
159 struct statfs *
160 getmntpoint(const char *name)
161 {
162 	struct stat devstat, mntdevstat;
163 	char device[sizeof(_PATH_DEV) - 1 + MNAMELEN];
164 	char *ddevname;
165 	struct statfs *mntbuf, *statfsp;
166 	int i, mntsize, isdev;
167 	u_long len;
168 
169 	if (stat(name, &devstat) != 0)
170 		return (NULL);
171 	if (S_ISCHR(devstat.st_mode) || S_ISBLK(devstat.st_mode))
172 		isdev = 1;
173 	else
174 		isdev = 0;
175 	mntsize = getmntinfo(&mntbuf, MNT_NOWAIT);
176 	for (i = 0; i < mntsize; i++) {
177 		statfsp = &mntbuf[i];
178 		if (isdev == 0) {
179 			if (strcmp(name, statfsp->f_mntonname))
180 				continue;
181 			return (statfsp);
182 		}
183 		ddevname = statfsp->f_mntfromname;
184 		if (*ddevname != '/') {
185 			if ((len = strlen(_PATH_DEV) + strlen(ddevname) + 1) >
186 			    sizeof(statfsp->f_mntfromname) ||
187 			    len > sizeof(device))
188 				continue;
189 			strncpy(device, _PATH_DEV, len);
190 			strncat(device, ddevname, len);
191 			if (stat(device, &mntdevstat) == 0)
192 				strncpy(statfsp->f_mntfromname, device, len);
193 		}
194 		if (stat(ddevname, &mntdevstat) == 0 &&
195 		    mntdevstat.st_rdev == devstat.st_rdev)
196 			return (statfsp);
197 	}
198 	return (NULL);
199 }
200 
201 /*
202  * If possible reload a mounted filesystem.
203  * When prtmsg != NULL print a warning if a reload is attempted, but fails.
204  * Return 0 on success, 1 on failure.
205  */
206 int
207 chkdoreload(struct statfs *mntp,
208 	void (*prtmsg)(const char *, ...) __printflike(1,2))
209 {
210 	struct iovec *iov;
211 	int iovlen, error;
212 	char errmsg[255];
213 
214 	/*
215 	 * If the filesystem is not mounted it does not need to be reloaded.
216 	 * If it is mounted for writing, then it could not have been opened
217 	 * for writing by a utility, so does not need to be reloaded.
218 	 */
219 	if (mntp == NULL || (mntp->f_flags & MNT_RDONLY) == 0)
220 		return (0);
221 
222 	/*
223 	 * We modified a mounted file system.  Do a mount update on
224 	 * it so we can continue using it as safely as possible.
225 	 */
226 	iov = NULL;
227 	iovlen = 0;
228 	errmsg[0] = '\0';
229 	build_iovec(&iov, &iovlen, "fstype", __DECONST(void *, "ffs"), 4);
230 	build_iovec(&iov, &iovlen, "from", mntp->f_mntfromname, (size_t)-1);
231 	build_iovec(&iov, &iovlen, "fspath", mntp->f_mntonname, (size_t)-1);
232 	build_iovec(&iov, &iovlen, "errmsg", errmsg, sizeof(errmsg));
233 	build_iovec(&iov, &iovlen, "update", NULL, 0);
234 	build_iovec(&iov, &iovlen, "reload", NULL, 0);
235 	/*
236 	 * XX: We need the following line until we clean up
237 	 * nmount parsing of root mounts and NFS root mounts.
238 	 */
239 	build_iovec(&iov, &iovlen, "ro", NULL, 0);
240 	error = nmount(iov, iovlen, mntp->f_flags);
241 	free_iovec(&iov, &iovlen);
242 	if (error == 0)
243 		return (0);
244 	if (prtmsg != NULL)
245 		prtmsg("mount reload of '%s' failed: %s %s\n\n",
246 		    mntp->f_mntonname, strerror(errno), errmsg);
247 	return (1);
248 }
249 
250 void
251 build_iovec(struct iovec **iov, int *iovlen, const char *name, void *val,
252 	    size_t len)
253 {
254 	int i;
255 
256 	if (*iovlen < 0)
257 		return;
258 	i = *iovlen;
259 	*iov = realloc(*iov, sizeof **iov * (i + 2));
260 	if (*iov == NULL) {
261 		*iovlen = -1;
262 		return;
263 	}
264 	(*iov)[i].iov_base = strdup(name);
265 	(*iov)[i].iov_len = strlen(name) + 1;
266 	i++;
267 	(*iov)[i].iov_base = val;
268 	if (len == (size_t)-1) {
269 		if (val != NULL)
270 			len = strlen(val) + 1;
271 		else
272 			len = 0;
273 	}
274 	(*iov)[i].iov_len = (int)len;
275 	*iovlen = ++i;
276 }
277 
278 /*
279  * This function is needed for compatibility with parameters
280  * which used to use the mount_argf() command for the old mount() syscall.
281  */
282 void
283 build_iovec_argf(struct iovec **iov, int *iovlen, const char *name,
284     const char *fmt, ...)
285 {
286 	va_list ap;
287 	char val[255] = { 0 };
288 
289 	va_start(ap, fmt);
290 	vsnprintf(val, sizeof(val), fmt, ap);
291 	va_end(ap);
292 	build_iovec(iov, iovlen, name, strdup(val), (size_t)-1);
293 }
294 
295 /*
296  * Free the iovec and reset to NULL with zero length.  Useful for calling
297  * nmount in a loop.
298  */
299 void
300 free_iovec(struct iovec **iov, int *iovlen)
301 {
302 	int i;
303 
304 	for (i = 0; i < *iovlen; i += 2)
305 		free((*iov)[i].iov_base);
306 	free(*iov);
307 }
308