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