be_access.c revision 357001 
1/*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
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 * All rights reserved.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 *    notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 *    notice, this list of conditions and the following disclaimer in the
16 *    documentation and/or other materials provided with the distribution.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * SUCH DAMAGE.
29 */
30
31#include <sys/cdefs.h>
32__FBSDID("$FreeBSD: stable/11/lib/libbe/be_access.c 357001 2020-01-22 22:51:55Z kevans $");
33
34#include <sys/mntent.h>
35
36#include "be.h"
37#include "be_impl.h"
38
39struct be_mountcheck_info {
40	const char *path;
41	char *name;
42};
43
44struct be_mount_info {
45	libbe_handle_t *lbh;
46	const char *be;
47	const char *mountpoint;
48	int mntflags;
49	int deepmount;
50	int depth;
51};
52
53static int
54be_mountcheck_cb(zfs_handle_t *zfs_hdl, void *data)
55{
56	struct be_mountcheck_info *info;
57	char *mountpoint;
58
59	if (data == NULL)
60		return (1);
61	info = (struct be_mountcheck_info *)data;
62	if (!zfs_is_mounted(zfs_hdl, &mountpoint))
63		return (0);
64	if (strcmp(mountpoint, info->path) == 0) {
65		info->name = strdup(zfs_get_name(zfs_hdl));
66		free(mountpoint);
67		return (1);
68	}
69	free(mountpoint);
70	return (0);
71}
72
73/*
74 * Called from be_mount, uses the given zfs_handle and attempts to
75 * mount it at the passed mountpoint. If the deepmount flag is set, continue
76 * calling the function for each child dataset.
77 */
78static int
79be_mount_iter(zfs_handle_t *zfs_hdl, void *data)
80{
81	int err;
82	char *mountpoint;
83	char tmp[BE_MAXPATHLEN], zfs_mnt[BE_MAXPATHLEN];
84	struct be_mount_info *info;
85
86	info = (struct be_mount_info *)data;
87
88	if (zfs_is_mounted(zfs_hdl, &mountpoint)) {
89		free(mountpoint);
90		return (0);
91	}
92
93	/*
94	 * canmount and mountpoint are both ignored for the BE dataset, because
95	 * the rest of the system (kernel and loader) will effectively do the
96	 * same.
97	 */
98	if (info->depth == 0) {
99		snprintf(tmp, BE_MAXPATHLEN, "%s", info->mountpoint);
100	} else {
101		if (zfs_prop_get_int(zfs_hdl, ZFS_PROP_CANMOUNT) ==
102		    ZFS_CANMOUNT_OFF)
103			return (0);
104
105		if (zfs_prop_get(zfs_hdl, ZFS_PROP_MOUNTPOINT, zfs_mnt,
106		    BE_MAXPATHLEN, NULL, NULL, 0, 1))
107			return (1);
108
109		/*
110		 * We've encountered mountpoint=none at some intermediate
111		 * dataset (e.g. zroot/var) that will have children that may
112		 * need to be mounted.  Skip mounting it, but iterate through
113		 * the children.
114		 */
115		if (strcmp("none", zfs_mnt) == 0)
116			goto skipmount;
117
118		mountpoint = be_mountpoint_augmented(info->lbh, zfs_mnt);
119		snprintf(tmp, BE_MAXPATHLEN, "%s%s", info->mountpoint,
120		    mountpoint);
121	}
122
123	if ((err = zfs_mount_at(zfs_hdl, NULL, info->mntflags, tmp)) != 0) {
124		switch (errno) {
125		case ENAMETOOLONG:
126			return (set_error(info->lbh, BE_ERR_PATHLEN));
127		case ELOOP:
128		case ENOENT:
129		case ENOTDIR:
130			return (set_error(info->lbh, BE_ERR_BADPATH));
131		case EPERM:
132			return (set_error(info->lbh, BE_ERR_PERMS));
133		case EBUSY:
134			return (set_error(info->lbh, BE_ERR_PATHBUSY));
135		default:
136			return (set_error(info->lbh, BE_ERR_UNKNOWN));
137		}
138	}
139
140	if (!info->deepmount)
141		return (0);
142
143skipmount:
144	++info->depth;
145	err = zfs_iter_filesystems(zfs_hdl, be_mount_iter, info);
146	--info->depth;
147	return (err);
148}
149
150
151static int
152be_umount_iter(zfs_handle_t *zfs_hdl, void *data)
153{
154
155	int err;
156	char *mountpoint;
157	struct be_mount_info *info;
158
159	info = (struct be_mount_info *)data;
160
161	++info->depth;
162	if((err = zfs_iter_filesystems(zfs_hdl, be_umount_iter, info)) != 0) {
163		return (err);
164	}
165	--info->depth;
166
167	if (!zfs_is_mounted(zfs_hdl, &mountpoint)) {
168		return (0);
169	}
170	free(mountpoint);
171
172	if (zfs_unmount(zfs_hdl, NULL, info->mntflags) != 0) {
173		switch (errno) {
174		case ENAMETOOLONG:
175			return (set_error(info->lbh, BE_ERR_PATHLEN));
176		case ELOOP:
177		case ENOENT:
178		case ENOTDIR:
179			return (set_error(info->lbh, BE_ERR_BADPATH));
180		case EPERM:
181			return (set_error(info->lbh, BE_ERR_PERMS));
182		case EBUSY:
183			return (set_error(info->lbh, BE_ERR_PATHBUSY));
184		default:
185			return (set_error(info->lbh, BE_ERR_UNKNOWN));
186		}
187	}
188	return (0);
189}
190
191/*
192 * usage
193 */
194int
195be_mounted_at(libbe_handle_t *lbh, const char *path, nvlist_t *details)
196{
197	char be[BE_MAXPATHLEN];
198	zfs_handle_t *root_hdl;
199	struct be_mountcheck_info info;
200	prop_data_t propinfo;
201
202	bzero(&be, BE_MAXPATHLEN);
203	if ((root_hdl = zfs_open(lbh->lzh, lbh->root,
204	    ZFS_TYPE_FILESYSTEM)) == NULL)
205		return (BE_ERR_ZFSOPEN);
206
207	info.path = path;
208	info.name = NULL;
209	zfs_iter_filesystems(root_hdl, be_mountcheck_cb, &info);
210	zfs_close(root_hdl);
211
212	if (info.name != NULL) {
213		if (details != NULL) {
214			if ((root_hdl = zfs_open(lbh->lzh, lbh->root,
215			    ZFS_TYPE_FILESYSTEM)) == NULL) {
216				free(info.name);
217				return (BE_ERR_ZFSOPEN);
218			}
219
220			propinfo.lbh = lbh;
221			propinfo.list = details;
222			propinfo.single_object = false;
223			prop_list_builder_cb(root_hdl, &propinfo);
224			zfs_close(root_hdl);
225		}
226		free(info.name);
227		return (0);
228	}
229	return (1);
230}
231
232/*
233 * usage
234 */
235int
236be_mount(libbe_handle_t *lbh, char *bootenv, char *mountpoint, int flags,
237    char *result_loc)
238{
239	char be[BE_MAXPATHLEN];
240	char mnt_temp[BE_MAXPATHLEN];
241	int mntflags, mntdeep;
242	int err;
243	struct be_mount_info info;
244	zfs_handle_t *zhdl;
245
246	if ((err = be_root_concat(lbh, bootenv, be)) != 0)
247		return (set_error(lbh, err));
248
249	if ((err = be_exists(lbh, bootenv)) != 0)
250		return (set_error(lbh, err));
251
252	if (is_mounted(lbh->lzh, be, NULL))
253		return (set_error(lbh, BE_ERR_MOUNTED));
254
255	mntdeep = (flags & BE_MNT_DEEP) ? 1 : 0;
256	mntflags = (flags & BE_MNT_FORCE) ? MNT_FORCE : 0;
257
258	/* Create mountpoint if it is not specified */
259	if (mountpoint == NULL) {
260		strlcpy(mnt_temp, "/tmp/be_mount.XXXX", sizeof(mnt_temp));
261		if (mkdtemp(mnt_temp) == NULL)
262			return (set_error(lbh, BE_ERR_IO));
263	}
264
265	if ((zhdl = zfs_open(lbh->lzh, be, ZFS_TYPE_FILESYSTEM)) == NULL)
266		return (set_error(lbh, BE_ERR_ZFSOPEN));
267
268	info.lbh = lbh;
269	info.be = be;
270	info.mountpoint = (mountpoint == NULL) ? mnt_temp : mountpoint;
271	info.mntflags = mntflags;
272	info.deepmount = mntdeep;
273	info.depth = 0;
274
275	if((err = be_mount_iter(zhdl, &info) != 0)) {
276		zfs_close(zhdl);
277		return (err);
278	}
279	zfs_close(zhdl);
280
281	if (result_loc != NULL)
282		strlcpy(result_loc, mountpoint == NULL ? mnt_temp : mountpoint,
283		    BE_MAXPATHLEN);
284
285	return (BE_ERR_SUCCESS);
286}
287
288/*
289 * usage
290 */
291int
292be_unmount(libbe_handle_t *lbh, char *bootenv, int flags)
293{
294	int err;
295	char be[BE_MAXPATHLEN];
296	zfs_handle_t *root_hdl;
297	struct be_mount_info info;
298
299	if ((err = be_root_concat(lbh, bootenv, be)) != 0)
300		return (set_error(lbh, err));
301
302	if ((root_hdl = zfs_open(lbh->lzh, be, ZFS_TYPE_FILESYSTEM)) == NULL)
303		return (set_error(lbh, BE_ERR_ZFSOPEN));
304
305	info.lbh = lbh;
306	info.be = be;
307	info.mountpoint = NULL;
308	info.mntflags = (flags & BE_MNT_FORCE) ? MS_FORCE : 0;
309	info.depth = 0;
310
311	if ((err = be_umount_iter(root_hdl, &info)) != 0) {
312		zfs_close(root_hdl);
313		return (err);
314	}
315
316	zfs_close(root_hdl);
317	return (BE_ERR_SUCCESS);
318}
319
320/*
321 * This function will blow away the input buffer as needed if we're discovered
322 * to be looking at a root-mount.  If the mountpoint is naturally beyond the
323 * root, however, the buffer may be left intact and a pointer to the section
324 * past altroot will be returned instead for the caller's perusal.
325 */
326char *
327be_mountpoint_augmented(libbe_handle_t *lbh, char *mountpoint)
328{
329
330	if (lbh->altroot_len == 0)
331		return (mountpoint);
332	if (mountpoint == NULL || *mountpoint == '\0')
333		return (mountpoint);
334
335	if (mountpoint[lbh->altroot_len] == '\0') {
336		*(mountpoint + 1) = '\0';
337		return (mountpoint);
338	} else
339		return (mountpoint + lbh->altroot_len);
340}
341