xref: /freebsd/lib/libbe/be_access.c (revision 7fdf597e96a02165cfe22ff357b857d5fa15ed8a)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
3  *
4  * Copyright (c) 2017 Kyle J. Kneitinger <kyle@kneit.in>
5  * Copyright (c) 2018 Kyle Evans <kevans@FreeBSD.org>
6  * Copyright (c) 2019 Wes Maag <wes@jwmaag.org>
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  */
29 
30 #include <sys/cdefs.h>
31 #include <sys/mntent.h>
32 
33 #include "be.h"
34 #include "be_impl.h"
35 
36 struct be_mountcheck_info {
37 	const char *path;
38 	char *name;
39 };
40 
41 struct be_mount_info {
42 	libbe_handle_t *lbh;
43 	const char *be;
44 	const char *mountpoint;
45 	int mntflags;
46 	int deepmount;
47 	int depth;
48 };
49 
50 static int
51 be_mountcheck_cb(zfs_handle_t *zfs_hdl, void *data)
52 {
53 	struct be_mountcheck_info *info;
54 	char *mountpoint;
55 
56 	if (data == NULL)
57 		return (1);
58 	info = (struct be_mountcheck_info *)data;
59 	if (!zfs_is_mounted(zfs_hdl, &mountpoint))
60 		return (0);
61 	if (strcmp(mountpoint, info->path) == 0) {
62 		info->name = strdup(zfs_get_name(zfs_hdl));
63 		free(mountpoint);
64 		return (1);
65 	}
66 	free(mountpoint);
67 	return (0);
68 }
69 
70 /*
71  * Called from be_mount, uses the given zfs_handle and attempts to
72  * mount it at the passed mountpoint. If the deepmount flag is set, continue
73  * calling the function for each child dataset.
74  */
75 static int
76 be_mount_iter(zfs_handle_t *zfs_hdl, void *data)
77 {
78 	int err;
79 	char *mountpoint;
80 	char tmp[BE_MAXPATHLEN], zfs_mnt[BE_MAXPATHLEN];
81 	struct be_mount_info *info;
82 
83 	info = (struct be_mount_info *)data;
84 
85 	if (zfs_is_mounted(zfs_hdl, &mountpoint)) {
86 		free(mountpoint);
87 		return (0);
88 	}
89 
90 	/*
91 	 * canmount and mountpoint are both ignored for the BE dataset, because
92 	 * the rest of the system (kernel and loader) will effectively do the
93 	 * same.
94 	 */
95 	if (info->depth == 0) {
96 		snprintf(tmp, BE_MAXPATHLEN, "%s", info->mountpoint);
97 	} else {
98 		if (zfs_prop_get_int(zfs_hdl, ZFS_PROP_CANMOUNT) ==
99 		    ZFS_CANMOUNT_OFF)
100 			return (0);
101 
102 		if (zfs_prop_get(zfs_hdl, ZFS_PROP_MOUNTPOINT, zfs_mnt,
103 		    BE_MAXPATHLEN, NULL, NULL, 0, 1))
104 			return (1);
105 
106 		/*
107 		 * We've encountered mountpoint=none at some intermediate
108 		 * dataset (e.g. zroot/var) that will have children that may
109 		 * need to be mounted.  Skip mounting it, but iterate through
110 		 * the children.
111 		 */
112 		if (strcmp("none", zfs_mnt) == 0)
113 			goto skipmount;
114 
115 		mountpoint = be_mountpoint_augmented(info->lbh, zfs_mnt);
116 		snprintf(tmp, BE_MAXPATHLEN, "%s%s", info->mountpoint,
117 		    mountpoint);
118 	}
119 
120 	if ((err = zfs_mount_at(zfs_hdl, NULL, info->mntflags, tmp)) != 0) {
121 		switch (errno) {
122 		case ENAMETOOLONG:
123 			return (set_error(info->lbh, BE_ERR_PATHLEN));
124 		case ELOOP:
125 		case ENOENT:
126 		case ENOTDIR:
127 			return (set_error(info->lbh, BE_ERR_BADPATH));
128 		case EPERM:
129 			return (set_error(info->lbh, BE_ERR_PERMS));
130 		case EBUSY:
131 			return (set_error(info->lbh, BE_ERR_PATHBUSY));
132 		default:
133 			return (set_error(info->lbh, BE_ERR_UNKNOWN));
134 		}
135 	}
136 
137 	if (!info->deepmount)
138 		return (0);
139 
140 skipmount:
141 	++info->depth;
142 	err = zfs_iter_filesystems(zfs_hdl, be_mount_iter, info);
143 	--info->depth;
144 	return (err);
145 }
146 
147 
148 static int
149 be_umount_iter(zfs_handle_t *zfs_hdl, void *data)
150 {
151 
152 	int err;
153 	char *mountpoint;
154 	struct be_mount_info *info;
155 
156 	info = (struct be_mount_info *)data;
157 
158 	++info->depth;
159 	if((err = zfs_iter_filesystems(zfs_hdl, be_umount_iter, info)) != 0) {
160 		return (err);
161 	}
162 	--info->depth;
163 
164 	if (!zfs_is_mounted(zfs_hdl, &mountpoint)) {
165 		return (0);
166 	}
167 	free(mountpoint);
168 
169 	if (zfs_unmount(zfs_hdl, NULL, info->mntflags) != 0) {
170 		switch (errno) {
171 		case ENAMETOOLONG:
172 			return (set_error(info->lbh, BE_ERR_PATHLEN));
173 		case ELOOP:
174 		case ENOENT:
175 		case ENOTDIR:
176 			return (set_error(info->lbh, BE_ERR_BADPATH));
177 		case EPERM:
178 			return (set_error(info->lbh, BE_ERR_PERMS));
179 		case EBUSY:
180 			return (set_error(info->lbh, BE_ERR_PATHBUSY));
181 		default:
182 			return (set_error(info->lbh, BE_ERR_UNKNOWN));
183 		}
184 	}
185 	return (0);
186 }
187 
188 /*
189  * usage
190  */
191 int
192 be_mounted_at(libbe_handle_t *lbh, const char *path, nvlist_t *details)
193 {
194 	char be[BE_MAXPATHLEN];
195 	zfs_handle_t *root_hdl;
196 	struct be_mountcheck_info info;
197 	prop_data_t propinfo;
198 
199 	bzero(&be, BE_MAXPATHLEN);
200 	if ((root_hdl = zfs_open(lbh->lzh, lbh->root,
201 	    ZFS_TYPE_FILESYSTEM)) == NULL)
202 		return (BE_ERR_ZFSOPEN);
203 
204 	info.path = path;
205 	info.name = NULL;
206 	zfs_iter_filesystems(root_hdl, be_mountcheck_cb, &info);
207 	zfs_close(root_hdl);
208 
209 	if (info.name != NULL) {
210 		if (details != NULL) {
211 			if ((root_hdl = zfs_open(lbh->lzh, info.name,
212 			    ZFS_TYPE_FILESYSTEM)) == NULL) {
213 				free(info.name);
214 				return (BE_ERR_ZFSOPEN);
215 			}
216 
217 			propinfo.lbh = lbh;
218 			propinfo.list = details;
219 			propinfo.single_object = false;
220 			propinfo.bootonce = NULL;
221 			prop_list_builder_cb(root_hdl, &propinfo);
222 			zfs_close(root_hdl);
223 		}
224 		free(info.name);
225 		return (0);
226 	}
227 	return (1);
228 }
229 
230 /*
231  * usage
232  */
233 int
234 be_mount(libbe_handle_t *lbh, const char *bootenv, const char *mountpoint,
235     int flags, char *result_loc)
236 {
237 	char be[BE_MAXPATHLEN];
238 	char mnt_temp[BE_MAXPATHLEN];
239 	int mntflags, mntdeep;
240 	int err;
241 	struct be_mount_info info;
242 	zfs_handle_t *zhdl;
243 
244 	if ((err = be_root_concat(lbh, bootenv, be)) != 0)
245 		return (set_error(lbh, err));
246 
247 	if ((err = be_exists(lbh, bootenv)) != 0)
248 		return (set_error(lbh, err));
249 
250 	if (is_mounted(lbh->lzh, be, NULL))
251 		return (set_error(lbh, BE_ERR_MOUNTED));
252 
253 	mntdeep = (flags & BE_MNT_DEEP) ? 1 : 0;
254 	mntflags = (flags & BE_MNT_FORCE) ? MNT_FORCE : 0;
255 
256 	/* Create mountpoint if it is not specified */
257 	if (mountpoint == NULL) {
258 		strlcpy(mnt_temp, "/tmp/be_mount.XXXX", sizeof(mnt_temp));
259 		if (mkdtemp(mnt_temp) == NULL)
260 			return (set_error(lbh, BE_ERR_IO));
261 	}
262 
263 	if ((zhdl = zfs_open(lbh->lzh, be, ZFS_TYPE_FILESYSTEM)) == NULL)
264 		return (set_error(lbh, BE_ERR_ZFSOPEN));
265 
266 	info.lbh = lbh;
267 	info.be = be;
268 	info.mountpoint = (mountpoint == NULL) ? mnt_temp : mountpoint;
269 	info.mntflags = mntflags;
270 	info.deepmount = mntdeep;
271 	info.depth = 0;
272 
273 	if((err = be_mount_iter(zhdl, &info) != 0)) {
274 		zfs_close(zhdl);
275 		return (err);
276 	}
277 	zfs_close(zhdl);
278 
279 	if (result_loc != NULL)
280 		strlcpy(result_loc, mountpoint == NULL ? mnt_temp : mountpoint,
281 		    BE_MAXPATHLEN);
282 
283 	return (BE_ERR_SUCCESS);
284 }
285 
286 /*
287  * usage
288  */
289 int
290 be_unmount(libbe_handle_t *lbh, const char *bootenv, int flags)
291 {
292 	int err;
293 	char be[BE_MAXPATHLEN];
294 	zfs_handle_t *root_hdl;
295 	struct be_mount_info info;
296 
297 	if ((err = be_root_concat(lbh, bootenv, be)) != 0)
298 		return (set_error(lbh, err));
299 
300 	if ((root_hdl = zfs_open(lbh->lzh, be, ZFS_TYPE_FILESYSTEM)) == NULL)
301 		return (set_error(lbh, BE_ERR_ZFSOPEN));
302 
303 	info.lbh = lbh;
304 	info.be = be;
305 	info.mountpoint = NULL;
306 	info.mntflags = (flags & BE_MNT_FORCE) ? MS_FORCE : 0;
307 	info.depth = 0;
308 
309 	if ((err = be_umount_iter(root_hdl, &info)) != 0) {
310 		zfs_close(root_hdl);
311 		return (err);
312 	}
313 
314 	zfs_close(root_hdl);
315 	return (BE_ERR_SUCCESS);
316 }
317 
318 /*
319  * This function will blow away the input buffer as needed if we're discovered
320  * to be looking at a root-mount.  If the mountpoint is naturally beyond the
321  * root, however, the buffer may be left intact and a pointer to the section
322  * past altroot will be returned instead for the caller's perusal.
323  */
324 char *
325 be_mountpoint_augmented(libbe_handle_t *lbh, char *mountpoint)
326 {
327 
328 	if (lbh->altroot_len == 0)
329 		return (mountpoint);
330 	if (mountpoint == NULL || *mountpoint == '\0')
331 		return (mountpoint);
332 
333 	if (mountpoint[lbh->altroot_len] == '\0') {
334 		*(mountpoint + 1) = '\0';
335 		return (mountpoint);
336 	} else
337 		return (mountpoint + lbh->altroot_len);
338 }
339