be_access.c revision 346429 
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 346429 2019-04-20 04:16:51Z 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};
49
50static int
51be_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 */
75static int
76be_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	if (zfs_prop_get_int(zfs_hdl, ZFS_PROP_CANMOUNT) == ZFS_CANMOUNT_OFF)
91		return (0);
92
93	if (zfs_prop_get(zfs_hdl, ZFS_PROP_MOUNTPOINT, zfs_mnt, BE_MAXPATHLEN,
94	    NULL, NULL, 0, 1))
95		return (1);
96
97	if (strcmp("none", zfs_mnt) != 0) {
98		char opt = '\0';
99
100		mountpoint = be_mountpoint_augmented(info->lbh, zfs_mnt);
101
102		snprintf(tmp, BE_MAXPATHLEN, "%s%s", info->mountpoint,
103		    mountpoint);
104
105		if ((err = zmount(zfs_get_name(zfs_hdl), tmp, info->mntflags,
106		 __DECONST(char *, MNTTYPE_ZFS), NULL, 0, &opt, 1)) != 0) {
107			switch (errno) {
108			case ENAMETOOLONG:
109				return (set_error(info->lbh, BE_ERR_PATHLEN));
110			case ELOOP:
111			case ENOENT:
112			case ENOTDIR:
113				return (set_error(info->lbh, BE_ERR_BADPATH));
114			case EPERM:
115				return (set_error(info->lbh, BE_ERR_PERMS));
116			case EBUSY:
117				return (set_error(info->lbh, BE_ERR_PATHBUSY));
118			default:
119				return (set_error(info->lbh, BE_ERR_UNKNOWN));
120			}
121		}
122	}
123
124	if (!info->deepmount)
125		return (0);
126
127	return (zfs_iter_filesystems(zfs_hdl, be_mount_iter, info));
128}
129
130
131static int
132be_umount_iter(zfs_handle_t *zfs_hdl, void *data)
133{
134
135	int err;
136	char *mountpoint;
137	struct be_mount_info *info;
138
139	info = (struct be_mount_info *)data;
140
141	if((err = zfs_iter_filesystems(zfs_hdl, be_umount_iter, info)) != 0) {
142		return (err);
143	}
144
145	if (!zfs_is_mounted(zfs_hdl, &mountpoint)) {
146		return (0);
147	}
148	free(mountpoint);
149
150	if (zfs_unmount(zfs_hdl, NULL, info->mntflags) != 0) {
151		switch (errno) {
152		case ENAMETOOLONG:
153			return (set_error(info->lbh, BE_ERR_PATHLEN));
154		case ELOOP:
155		case ENOENT:
156		case ENOTDIR:
157			return (set_error(info->lbh, BE_ERR_BADPATH));
158		case EPERM:
159			return (set_error(info->lbh, BE_ERR_PERMS));
160		case EBUSY:
161			return (set_error(info->lbh, BE_ERR_PATHBUSY));
162		default:
163			return (set_error(info->lbh, BE_ERR_UNKNOWN));
164		}
165	}
166	return (0);
167}
168
169/*
170 * usage
171 */
172int
173be_mounted_at(libbe_handle_t *lbh, const char *path, nvlist_t *details)
174{
175	char be[BE_MAXPATHLEN];
176	zfs_handle_t *root_hdl;
177	struct be_mountcheck_info info;
178	prop_data_t propinfo;
179
180	bzero(&be, BE_MAXPATHLEN);
181	if ((root_hdl = zfs_open(lbh->lzh, lbh->root,
182	    ZFS_TYPE_FILESYSTEM)) == NULL)
183		return (BE_ERR_ZFSOPEN);
184
185	info.path = path;
186	info.name = NULL;
187	zfs_iter_filesystems(root_hdl, be_mountcheck_cb, &info);
188	zfs_close(root_hdl);
189
190	if (info.name != NULL) {
191		if (details != NULL) {
192			if ((root_hdl = zfs_open(lbh->lzh, lbh->root,
193			    ZFS_TYPE_FILESYSTEM)) == NULL) {
194				free(info.name);
195				return (BE_ERR_ZFSOPEN);
196			}
197
198			propinfo.lbh = lbh;
199			propinfo.list = details;
200			propinfo.single_object = false;
201			prop_list_builder_cb(root_hdl, &propinfo);
202			zfs_close(root_hdl);
203		}
204		free(info.name);
205		return (0);
206	}
207	return (1);
208}
209
210/*
211 * usage
212 */
213int
214be_mount(libbe_handle_t *lbh, char *bootenv, char *mountpoint, int flags,
215    char *result_loc)
216{
217	char be[BE_MAXPATHLEN];
218	char mnt_temp[BE_MAXPATHLEN];
219	int mntflags, mntdeep;
220	int err;
221	struct be_mount_info info;
222	zfs_handle_t *zhdl;
223
224	if ((err = be_root_concat(lbh, bootenv, be)) != 0)
225		return (set_error(lbh, err));
226
227	if ((err = be_exists(lbh, bootenv)) != 0)
228		return (set_error(lbh, err));
229
230	if (is_mounted(lbh->lzh, be, NULL))
231		return (set_error(lbh, BE_ERR_MOUNTED));
232
233	mntdeep = (flags & BE_MNT_DEEP) ? 1 : 0;
234	mntflags = (flags & BE_MNT_FORCE) ? MNT_FORCE : 0;
235
236	/* Create mountpoint if it is not specified */
237	if (mountpoint == NULL) {
238		strlcpy(mnt_temp, "/tmp/be_mount.XXXX", sizeof(mnt_temp));
239		if (mkdtemp(mnt_temp) == NULL)
240			return (set_error(lbh, BE_ERR_IO));
241	}
242
243	if ((zhdl = zfs_open(lbh->lzh, be, ZFS_TYPE_FILESYSTEM)) == NULL)
244		return (set_error(lbh, BE_ERR_ZFSOPEN));
245
246	info.lbh = lbh;
247	info.be = be;
248	info.mountpoint = (mountpoint == NULL) ? mnt_temp : mountpoint;
249	info.mntflags = mntflags;
250	info.deepmount = mntdeep;
251
252	if((err = be_mount_iter(zhdl, &info) != 0)) {
253		zfs_close(zhdl);
254		return (err);
255	}
256	zfs_close(zhdl);
257
258	if (result_loc != NULL)
259		strlcpy(result_loc, mountpoint == NULL ? mnt_temp : mountpoint,
260		    BE_MAXPATHLEN);
261
262	return (BE_ERR_SUCCESS);
263}
264
265/*
266 * usage
267 */
268int
269be_unmount(libbe_handle_t *lbh, char *bootenv, int flags)
270{
271	int err;
272	char be[BE_MAXPATHLEN];
273	zfs_handle_t *root_hdl;
274	struct be_mount_info info;
275
276	if ((err = be_root_concat(lbh, bootenv, be)) != 0)
277		return (set_error(lbh, err));
278
279	if ((root_hdl = zfs_open(lbh->lzh, be, ZFS_TYPE_FILESYSTEM)) == NULL)
280		return (set_error(lbh, BE_ERR_ZFSOPEN));
281
282	info.lbh = lbh;
283	info.be = be;
284	info.mountpoint = NULL;
285	info.mntflags = (flags & BE_MNT_FORCE) ? MS_FORCE : 0;
286
287	if ((err = be_umount_iter(root_hdl, &info)) != 0) {
288		zfs_close(root_hdl);
289		return (err);
290	}
291
292	zfs_close(root_hdl);
293	return (BE_ERR_SUCCESS);
294}
295
296/*
297 * This function will blow away the input buffer as needed if we're discovered
298 * to be looking at a root-mount.  If the mountpoint is naturally beyond the
299 * root, however, the buffer may be left intact and a pointer to the section
300 * past altroot will be returned instead for the caller's perusal.
301 */
302char *
303be_mountpoint_augmented(libbe_handle_t *lbh, char *mountpoint)
304{
305
306	if (lbh->altroot_len == 0)
307		return (mountpoint);
308	if (mountpoint == NULL || *mountpoint == '\0')
309		return (mountpoint);
310
311	if (mountpoint[lbh->altroot_len] == '\0') {
312		*(mountpoint + 1) = '\0';
313		return (mountpoint);
314	} else
315		return (mountpoint + lbh->altroot_len);
316}
317