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 *
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__FBSDID("$FreeBSD: stable/11/lib/libbe/be_access.c 357667 2020-02-07 21:57:27Z kevans $");
32
33#include <sys/mntent.h>
34
35#include "be.h"
36#include "be_impl.h"
37
38struct be_mountcheck_info {
39	const char *path;
40	char *name;
41};
42
43struct be_mount_info {
44	libbe_handle_t *lbh;
45	const char *be;
46	const char *mountpoint;
47	int mntflags;
48	int deepmount;
49	int depth;
50};
51
52static int
53be_mountcheck_cb(zfs_handle_t *zfs_hdl, void *data)
54{
55	struct be_mountcheck_info *info;
56	char *mountpoint;
57
58	if (data == NULL)
59		return (1);
60	info = (struct be_mountcheck_info *)data;
61	if (!zfs_is_mounted(zfs_hdl, &mountpoint))
62		return (0);
63	if (strcmp(mountpoint, info->path) == 0) {
64		info->name = strdup(zfs_get_name(zfs_hdl));
65		free(mountpoint);
66		return (1);
67	}
68	free(mountpoint);
69	return (0);
70}
71
72/*
73 * Called from be_mount, uses the given zfs_handle and attempts to
74 * mount it at the passed mountpoint. If the deepmount flag is set, continue
75 * calling the function for each child dataset.
76 */
77static int
78be_mount_iter(zfs_handle_t *zfs_hdl, void *data)
79{
80	int err;
81	char *mountpoint;
82	char tmp[BE_MAXPATHLEN], zfs_mnt[BE_MAXPATHLEN];
83	struct be_mount_info *info;
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	/*
93	 * canmount and mountpoint are both ignored for the BE dataset, because
94	 * the rest of the system (kernel and loader) will effectively do the
95	 * same.
96	 */
97	if (info->depth == 0) {
98		snprintf(tmp, BE_MAXPATHLEN, "%s", info->mountpoint);
99	} else {
100		if (zfs_prop_get_int(zfs_hdl, ZFS_PROP_CANMOUNT) ==
101		    ZFS_CANMOUNT_OFF)
102			return (0);
103
104		if (zfs_prop_get(zfs_hdl, ZFS_PROP_MOUNTPOINT, zfs_mnt,
105		    BE_MAXPATHLEN, NULL, NULL, 0, 1))
106			return (1);
107
108		/*
109		 * We've encountered mountpoint=none at some intermediate
110		 * dataset (e.g. zroot/var) that will have children that may
111		 * need to be mounted.  Skip mounting it, but iterate through
112		 * the children.
113		 */
114		if (strcmp("none", zfs_mnt) == 0)
115			goto skipmount;
116
117		mountpoint = be_mountpoint_augmented(info->lbh, zfs_mnt);
118		snprintf(tmp, BE_MAXPATHLEN, "%s%s", info->mountpoint,
119		    mountpoint);
120	}
121
122	if ((err = zfs_mount_at(zfs_hdl, NULL, info->mntflags, tmp)) != 0) {
123		switch (errno) {
124		case ENAMETOOLONG:
125			return (set_error(info->lbh, BE_ERR_PATHLEN));
126		case ELOOP:
127		case ENOENT:
128		case ENOTDIR:
129			return (set_error(info->lbh, BE_ERR_BADPATH));
130		case EPERM:
131			return (set_error(info->lbh, BE_ERR_PERMS));
132		case EBUSY:
133			return (set_error(info->lbh, BE_ERR_PATHBUSY));
134		default:
135			return (set_error(info->lbh, BE_ERR_UNKNOWN));
136		}
137	}
138
139	if (!info->deepmount)
140		return (0);
141
142skipmount:
143	++info->depth;
144	err = zfs_iter_filesystems(zfs_hdl, be_mount_iter, info);
145	--info->depth;
146	return (err);
147}
148
149
150static int
151be_umount_iter(zfs_handle_t *zfs_hdl, void *data)
152{
153
154	int err;
155	char *mountpoint;
156	struct be_mount_info *info;
157
158	info = (struct be_mount_info *)data;
159
160	++info->depth;
161	if((err = zfs_iter_filesystems(zfs_hdl, be_umount_iter, info)) != 0) {
162		return (err);
163	}
164	--info->depth;
165
166	if (!zfs_is_mounted(zfs_hdl, &mountpoint)) {
167		return (0);
168	}
169	free(mountpoint);
170
171	if (zfs_unmount(zfs_hdl, NULL, info->mntflags) != 0) {
172		switch (errno) {
173		case ENAMETOOLONG:
174			return (set_error(info->lbh, BE_ERR_PATHLEN));
175		case ELOOP:
176		case ENOENT:
177		case ENOTDIR:
178			return (set_error(info->lbh, BE_ERR_BADPATH));
179		case EPERM:
180			return (set_error(info->lbh, BE_ERR_PERMS));
181		case EBUSY:
182			return (set_error(info->lbh, BE_ERR_PATHBUSY));
183		default:
184			return (set_error(info->lbh, BE_ERR_UNKNOWN));
185		}
186	}
187	return (0);
188}
189
190/*
191 * usage
192 */
193int
194be_mounted_at(libbe_handle_t *lbh, const char *path, nvlist_t *details)
195{
196	char be[BE_MAXPATHLEN];
197	zfs_handle_t *root_hdl;
198	struct be_mountcheck_info info;
199	prop_data_t propinfo;
200
201	bzero(&be, BE_MAXPATHLEN);
202	if ((root_hdl = zfs_open(lbh->lzh, lbh->root,
203	    ZFS_TYPE_FILESYSTEM)) == NULL)
204		return (BE_ERR_ZFSOPEN);
205
206	info.path = path;
207	info.name = NULL;
208	zfs_iter_filesystems(root_hdl, be_mountcheck_cb, &info);
209	zfs_close(root_hdl);
210
211	if (info.name != NULL) {
212		if (details != NULL) {
213			if ((root_hdl = zfs_open(lbh->lzh, lbh->root,
214			    ZFS_TYPE_FILESYSTEM)) == NULL) {
215				free(info.name);
216				return (BE_ERR_ZFSOPEN);
217			}
218
219			propinfo.lbh = lbh;
220			propinfo.list = details;
221			propinfo.single_object = false;
222			prop_list_builder_cb(root_hdl, &propinfo);
223			zfs_close(root_hdl);
224		}
225		free(info.name);
226		return (0);
227	}
228	return (1);
229}
230
231/*
232 * usage
233 */
234int
235be_mount(libbe_handle_t *lbh, char *bootenv, char *mountpoint, int flags,
236    char *result_loc)
237{
238	char be[BE_MAXPATHLEN];
239	char mnt_temp[BE_MAXPATHLEN];
240	int mntflags, mntdeep;
241	int err;
242	struct be_mount_info info;
243	zfs_handle_t *zhdl;
244
245	if ((err = be_root_concat(lbh, bootenv, be)) != 0)
246		return (set_error(lbh, err));
247
248	if ((err = be_exists(lbh, bootenv)) != 0)
249		return (set_error(lbh, err));
250
251	if (is_mounted(lbh->lzh, be, NULL))
252		return (set_error(lbh, BE_ERR_MOUNTED));
253
254	mntdeep = (flags & BE_MNT_DEEP) ? 1 : 0;
255	mntflags = (flags & BE_MNT_FORCE) ? MNT_FORCE : 0;
256
257	/* Create mountpoint if it is not specified */
258	if (mountpoint == NULL) {
259		strlcpy(mnt_temp, "/tmp/be_mount.XXXX", sizeof(mnt_temp));
260		if (mkdtemp(mnt_temp) == NULL)
261			return (set_error(lbh, BE_ERR_IO));
262	}
263
264	if ((zhdl = zfs_open(lbh->lzh, be, ZFS_TYPE_FILESYSTEM)) == NULL)
265		return (set_error(lbh, BE_ERR_ZFSOPEN));
266
267	info.lbh = lbh;
268	info.be = be;
269	info.mountpoint = (mountpoint == NULL) ? mnt_temp : mountpoint;
270	info.mntflags = mntflags;
271	info.deepmount = mntdeep;
272	info.depth = 0;
273
274	if((err = be_mount_iter(zhdl, &info) != 0)) {
275		zfs_close(zhdl);
276		return (err);
277	}
278	zfs_close(zhdl);
279
280	if (result_loc != NULL)
281		strlcpy(result_loc, mountpoint == NULL ? mnt_temp : mountpoint,
282		    BE_MAXPATHLEN);
283
284	return (BE_ERR_SUCCESS);
285}
286
287/*
288 * usage
289 */
290int
291be_unmount(libbe_handle_t *lbh, char *bootenv, int flags)
292{
293	int err;
294	char be[BE_MAXPATHLEN];
295	zfs_handle_t *root_hdl;
296	struct be_mount_info info;
297
298	if ((err = be_root_concat(lbh, bootenv, be)) != 0)
299		return (set_error(lbh, err));
300
301	if ((root_hdl = zfs_open(lbh->lzh, be, ZFS_TYPE_FILESYSTEM)) == NULL)
302		return (set_error(lbh, BE_ERR_ZFSOPEN));
303
304	info.lbh = lbh;
305	info.be = be;
306	info.mountpoint = NULL;
307	info.mntflags = (flags & BE_MNT_FORCE) ? MS_FORCE : 0;
308	info.depth = 0;
309
310	if ((err = be_umount_iter(root_hdl, &info)) != 0) {
311		zfs_close(root_hdl);
312		return (err);
313	}
314
315	zfs_close(root_hdl);
316	return (BE_ERR_SUCCESS);
317}
318
319/*
320 * This function will blow away the input buffer as needed if we're discovered
321 * to be looking at a root-mount.  If the mountpoint is naturally beyond the
322 * root, however, the buffer may be left intact and a pointer to the section
323 * past altroot will be returned instead for the caller's perusal.
324 */
325char *
326be_mountpoint_augmented(libbe_handle_t *lbh, char *mountpoint)
327{
328
329	if (lbh->altroot_len == 0)
330		return (mountpoint);
331	if (mountpoint == NULL || *mountpoint == '\0')
332		return (mountpoint);
333
334	if (mountpoint[lbh->altroot_len] == '\0') {
335		*(mountpoint + 1) = '\0';
336		return (mountpoint);
337	} else
338		return (mountpoint + lbh->altroot_len);
339}
340