be_access.c revision 348133 
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 348133 2019-05-22 23:34:41Z kevans $");
33
34#include "be.h"
35#include "be_impl.h"
36
37struct be_mountcheck_info {
38	const char *path;
39	char *name;
40};
41
42struct be_mount_info {
43	libbe_handle_t *lbh;
44	const char *be;
45	const char *mountpoint;
46	int mntflags;
47	int deepmount;
48	int depth;
49};
50
51static int
52be_mountcheck_cb(zfs_handle_t *zfs_hdl, void *data)
53{
54	struct be_mountcheck_info *info;
55	char *mountpoint;
56
57	if (data == NULL)
58		return (1);
59	info = (struct be_mountcheck_info *)data;
60	if (!zfs_is_mounted(zfs_hdl, &mountpoint))
61		return (0);
62	if (strcmp(mountpoint, info->path) == 0) {
63		info->name = strdup(zfs_get_name(zfs_hdl));
64		free(mountpoint);
65		return (1);
66	}
67	free(mountpoint);
68	return (0);
69}
70
71/*
72 * Called from be_mount, uses the given zfs_handle and attempts to
73 * mount it at the passed mountpoint. If the deepmount flag is set, continue
74 * calling the function for each child dataset.
75 */
76static int
77be_mount_iter(zfs_handle_t *zfs_hdl, void *data)
78{
79	int err;
80	char *mountpoint;
81	char tmp[BE_MAXPATHLEN], zfs_mnt[BE_MAXPATHLEN];
82	struct be_mount_info *info;
83	char opt;
84
85	info = (struct be_mount_info *)data;
86
87	if (zfs_is_mounted(zfs_hdl, &mountpoint)) {
88		free(mountpoint);
89		return (0);
90	}
91
92	if (zfs_prop_get_int(zfs_hdl, ZFS_PROP_CANMOUNT) == ZFS_CANMOUNT_OFF)
93		return (0);
94
95	if (zfs_prop_get(zfs_hdl, ZFS_PROP_MOUNTPOINT, zfs_mnt, BE_MAXPATHLEN,
96	    NULL, NULL, 0, 1))
97		return (1);
98
99	if (strcmp("none", zfs_mnt) == 0) {
100		/*
101		 * mountpoint=none; we'll mount it at info->mountpoint assuming
102		 * we're at the root.  If we're not at the root, we're likely
103		 * at some intermediate dataset (e.g. zroot/var) that will have
104		 * children that may need to be mounted.
105		 */
106		if (info->depth > 0)
107			goto skipmount;
108
109		snprintf(tmp, BE_MAXPATHLEN, "%s", info->mountpoint);
110	} else {
111		mountpoint = be_mountpoint_augmented(info->lbh, zfs_mnt);
112		snprintf(tmp, BE_MAXPATHLEN, "%s%s", info->mountpoint,
113		    mountpoint);
114	}
115
116	opt = '\0';
117	if ((err = zmount(zfs_get_name(zfs_hdl), tmp, info->mntflags,
118	    __DECONST(char *, MNTTYPE_ZFS), NULL, 0, &opt, 1)) != 0) {
119		switch (errno) {
120		case ENAMETOOLONG:
121			return (set_error(info->lbh, BE_ERR_PATHLEN));
122		case ELOOP:
123		case ENOENT:
124		case ENOTDIR:
125			return (set_error(info->lbh, BE_ERR_BADPATH));
126		case EPERM:
127			return (set_error(info->lbh, BE_ERR_PERMS));
128		case EBUSY:
129			return (set_error(info->lbh, BE_ERR_PATHBUSY));
130		default:
131			return (set_error(info->lbh, BE_ERR_UNKNOWN));
132		}
133	}
134
135	if (!info->deepmount)
136		return (0);
137
138skipmount:
139	++info->depth;
140	err = zfs_iter_filesystems(zfs_hdl, be_mount_iter, info);
141	--info->depth;
142	return (err);
143}
144
145
146static int
147be_umount_iter(zfs_handle_t *zfs_hdl, void *data)
148{
149
150	int err;
151	char *mountpoint;
152	struct be_mount_info *info;
153
154	info = (struct be_mount_info *)data;
155
156	++info->depth;
157	if((err = zfs_iter_filesystems(zfs_hdl, be_umount_iter, info)) != 0) {
158		return (err);
159	}
160	--info->depth;
161
162	if (!zfs_is_mounted(zfs_hdl, &mountpoint)) {
163		return (0);
164	}
165	free(mountpoint);
166
167	if (zfs_unmount(zfs_hdl, NULL, info->mntflags) != 0) {
168		switch (errno) {
169		case ENAMETOOLONG:
170			return (set_error(info->lbh, BE_ERR_PATHLEN));
171		case ELOOP:
172		case ENOENT:
173		case ENOTDIR:
174			return (set_error(info->lbh, BE_ERR_BADPATH));
175		case EPERM:
176			return (set_error(info->lbh, BE_ERR_PERMS));
177		case EBUSY:
178			return (set_error(info->lbh, BE_ERR_PATHBUSY));
179		default:
180			return (set_error(info->lbh, BE_ERR_UNKNOWN));
181		}
182	}
183	return (0);
184}
185
186/*
187 * usage
188 */
189int
190be_mounted_at(libbe_handle_t *lbh, const char *path, nvlist_t *details)
191{
192	char be[BE_MAXPATHLEN];
193	zfs_handle_t *root_hdl;
194	struct be_mountcheck_info info;
195	prop_data_t propinfo;
196
197	bzero(&be, BE_MAXPATHLEN);
198	if ((root_hdl = zfs_open(lbh->lzh, lbh->root,
199	    ZFS_TYPE_FILESYSTEM)) == NULL)
200		return (BE_ERR_ZFSOPEN);
201
202	info.path = path;
203	info.name = NULL;
204	zfs_iter_filesystems(root_hdl, be_mountcheck_cb, &info);
205	zfs_close(root_hdl);
206
207	if (info.name != NULL) {
208		if (details != NULL) {
209			if ((root_hdl = zfs_open(lbh->lzh, lbh->root,
210			    ZFS_TYPE_FILESYSTEM)) == NULL) {
211				free(info.name);
212				return (BE_ERR_ZFSOPEN);
213			}
214
215			propinfo.lbh = lbh;
216			propinfo.list = details;
217			propinfo.single_object = false;
218			prop_list_builder_cb(root_hdl, &propinfo);
219			zfs_close(root_hdl);
220		}
221		free(info.name);
222		return (0);
223	}
224	return (1);
225}
226
227/*
228 * usage
229 */
230int
231be_mount(libbe_handle_t *lbh, char *bootenv, char *mountpoint, int flags,
232    char *result_loc)
233{
234	char be[BE_MAXPATHLEN];
235	char mnt_temp[BE_MAXPATHLEN];
236	int mntflags, mntdeep;
237	int err;
238	struct be_mount_info info;
239	zfs_handle_t *zhdl;
240
241	if ((err = be_root_concat(lbh, bootenv, be)) != 0)
242		return (set_error(lbh, err));
243
244	if ((err = be_exists(lbh, bootenv)) != 0)
245		return (set_error(lbh, err));
246
247	if (is_mounted(lbh->lzh, be, NULL))
248		return (set_error(lbh, BE_ERR_MOUNTED));
249
250	mntdeep = (flags & BE_MNT_DEEP) ? 1 : 0;
251	mntflags = (flags & BE_MNT_FORCE) ? MNT_FORCE : 0;
252
253	/* Create mountpoint if it is not specified */
254	if (mountpoint == NULL) {
255		strlcpy(mnt_temp, "/tmp/be_mount.XXXX", sizeof(mnt_temp));
256		if (mkdtemp(mnt_temp) == NULL)
257			return (set_error(lbh, BE_ERR_IO));
258	}
259
260	if ((zhdl = zfs_open(lbh->lzh, be, ZFS_TYPE_FILESYSTEM)) == NULL)
261		return (set_error(lbh, BE_ERR_ZFSOPEN));
262
263	info.lbh = lbh;
264	info.be = be;
265	info.mountpoint = (mountpoint == NULL) ? mnt_temp : mountpoint;
266	info.mntflags = mntflags;
267	info.deepmount = mntdeep;
268	info.depth = 0;
269
270	if((err = be_mount_iter(zhdl, &info) != 0)) {
271		zfs_close(zhdl);
272		return (err);
273	}
274	zfs_close(zhdl);
275
276	if (result_loc != NULL)
277		strlcpy(result_loc, mountpoint == NULL ? mnt_temp : mountpoint,
278		    BE_MAXPATHLEN);
279
280	return (BE_ERR_SUCCESS);
281}
282
283/*
284 * usage
285 */
286int
287be_unmount(libbe_handle_t *lbh, char *bootenv, int flags)
288{
289	int err;
290	char be[BE_MAXPATHLEN];
291	zfs_handle_t *root_hdl;
292	struct be_mount_info info;
293
294	if ((err = be_root_concat(lbh, bootenv, be)) != 0)
295		return (set_error(lbh, err));
296
297	if ((root_hdl = zfs_open(lbh->lzh, be, ZFS_TYPE_FILESYSTEM)) == NULL)
298		return (set_error(lbh, BE_ERR_ZFSOPEN));
299
300	info.lbh = lbh;
301	info.be = be;
302	info.mountpoint = NULL;
303	info.mntflags = (flags & BE_MNT_FORCE) ? MS_FORCE : 0;
304	info.depth = 0;
305
306	if ((err = be_umount_iter(root_hdl, &info)) != 0) {
307		zfs_close(root_hdl);
308		return (err);
309	}
310
311	zfs_close(root_hdl);
312	return (BE_ERR_SUCCESS);
313}
314
315/*
316 * This function will blow away the input buffer as needed if we're discovered
317 * to be looking at a root-mount.  If the mountpoint is naturally beyond the
318 * root, however, the buffer may be left intact and a pointer to the section
319 * past altroot will be returned instead for the caller's perusal.
320 */
321char *
322be_mountpoint_augmented(libbe_handle_t *lbh, char *mountpoint)
323{
324
325	if (lbh->altroot_len == 0)
326		return (mountpoint);
327	if (mountpoint == NULL || *mountpoint == '\0')
328		return (mountpoint);
329
330	if (mountpoint[lbh->altroot_len] == '\0') {
331		*(mountpoint + 1) = '\0';
332		return (mountpoint);
333	} else
334		return (mountpoint + lbh->altroot_len);
335}
336