1 // SPDX-License-Identifier: CDDL-1.0
2 /*
3 * CDDL HEADER START
4 *
5 * The contents of this file are subject to the terms of the
6 * Common Development and Distribution License (the "License").
7 * You may not use this file except in compliance with the License.
8 *
9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10 * or https://opensource.org/licenses/CDDL-1.0.
11 * See the License for the specific language governing permissions
12 * and limitations under the License.
13 *
14 * When distributing Covered Code, include this CDDL HEADER in each
15 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16 * If applicable, add the following below this CDDL HEADER, with the
17 * fields enclosed by brackets "[]" replaced with your own identifying
18 * information: Portions Copyright [yyyy] [name of copyright owner]
19 *
20 * CDDL HEADER END
21 */
22
23 /*
24 * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
25 * Copyright (c) 2011 Lawrence Livermore National Security, LLC.
26 */
27
28 #include <libintl.h>
29 #include <unistd.h>
30 #include <sys/file.h>
31 #include <sys/mount.h>
32 #include <sys/mntent.h>
33 #include <sys/stat.h>
34 #include <libzfs.h>
35 #include <libzutil.h>
36 #include <locale.h>
37 #include <getopt.h>
38 #include <fcntl.h>
39 #include <errno.h>
40
41 #define ZS_COMMENT 0x00000000 /* comment */
42 #define ZS_ZFSUTIL 0x00000001 /* caller is zfs(8) */
43
44 libzfs_handle_t *g_zfs;
45
46 /*
47 * Opportunistically convert a target string into a pool name. If the
48 * string does not represent a block device with a valid zfs label
49 * then it is passed through without modification.
50 */
51 static void
parse_dataset(const char * target,char ** dataset)52 parse_dataset(const char *target, char **dataset)
53 {
54 /*
55 * Prior to util-linux 2.36.2, if a file or directory in the
56 * current working directory was named 'dataset' then mount(8)
57 * would prepend the current working directory to the dataset.
58 * Check for it and strip the prepended path when it is added.
59 */
60 char cwd[PATH_MAX];
61 if (getcwd(cwd, PATH_MAX) == NULL) {
62 perror("getcwd");
63 return;
64 }
65 int len = strlen(cwd);
66 if (strncmp(cwd, target, len) == 0)
67 target += len;
68
69 /* Assume pool/dataset is more likely */
70 strlcpy(*dataset, target, PATH_MAX);
71
72 int fd = open(target, O_RDONLY | O_CLOEXEC);
73 if (fd < 0)
74 return;
75
76 nvlist_t *cfg = NULL;
77 if (zpool_read_label(fd, &cfg, NULL) == 0) {
78 const char *nm = NULL;
79 if (!nvlist_lookup_string(cfg, ZPOOL_CONFIG_POOL_NAME, &nm))
80 strlcpy(*dataset, nm, PATH_MAX);
81 nvlist_free(cfg);
82 }
83
84 if (close(fd))
85 perror("close");
86 }
87
88 /*
89 * Update the mtab_* code to use the libmount library when it is commonly
90 * available otherwise fallback to legacy mode. The mount(8) utility will
91 * manage the lock file for us to prevent racing updates to /etc/mtab.
92 */
93 static int
mtab_is_writeable(void)94 mtab_is_writeable(void)
95 {
96 struct stat st;
97 int error, fd;
98
99 error = lstat("/etc/mtab", &st);
100 if (error || S_ISLNK(st.st_mode))
101 return (0);
102
103 fd = open("/etc/mtab", O_RDWR | O_CREAT, 0644);
104 if (fd < 0)
105 return (0);
106
107 close(fd);
108 return (1);
109 }
110
111 static int
mtab_update(const char * dataset,const char * mntpoint,const char * type,const char * mntopts)112 mtab_update(const char *dataset, const char *mntpoint, const char *type,
113 const char *mntopts)
114 {
115 struct mntent mnt;
116 FILE *fp;
117 int error;
118
119 mnt.mnt_fsname = (char *)dataset;
120 mnt.mnt_dir = (char *)mntpoint;
121 mnt.mnt_type = (char *)type;
122 mnt.mnt_opts = (char *)(mntopts ?: "");
123 mnt.mnt_freq = 0;
124 mnt.mnt_passno = 0;
125
126 fp = setmntent("/etc/mtab", "a+e");
127 if (!fp) {
128 (void) fprintf(stderr, gettext(
129 "filesystem '%s' was mounted, but /etc/mtab "
130 "could not be opened due to error: %s\n"),
131 dataset, strerror(errno));
132 return (MOUNT_FILEIO);
133 }
134
135 error = addmntent(fp, &mnt);
136 if (error) {
137 (void) fprintf(stderr, gettext(
138 "filesystem '%s' was mounted, but /etc/mtab "
139 "could not be updated due to error: %s\n"),
140 dataset, strerror(errno));
141 return (MOUNT_FILEIO);
142 }
143
144 (void) endmntent(fp);
145
146 return (MOUNT_SUCCESS);
147 }
148
149 int
main(int argc,char ** argv)150 main(int argc, char **argv)
151 {
152 zfs_handle_t *zhp;
153 char prop[ZFS_MAXPROPLEN];
154 uint64_t zfs_version = 0;
155 char mntopts[MNT_LINE_MAX] = { '\0' };
156 char badopt[MNT_LINE_MAX] = { '\0' };
157 char mtabopt[MNT_LINE_MAX] = { '\0' };
158 char mntpoint[PATH_MAX];
159 char dataset[PATH_MAX], *pdataset = dataset;
160 unsigned long mntflags = 0, zfsflags = 0, remount = 0;
161 int sloppy = 0, fake = 0, verbose = 0, nomtab = 0, zfsutil = 0;
162 int error, c;
163
164 (void) setlocale(LC_ALL, "");
165 (void) setlocale(LC_NUMERIC, "C");
166 (void) textdomain(TEXT_DOMAIN);
167
168 opterr = 0;
169
170 /* check options */
171 while ((c = getopt_long(argc, argv, "sfnvo:h?", 0, 0)) != -1) {
172 switch (c) {
173 case 's':
174 sloppy = 1;
175 break;
176 case 'f':
177 fake = 1;
178 break;
179 case 'n':
180 nomtab = 1;
181 break;
182 case 'v':
183 verbose++;
184 break;
185 case 'o':
186 (void) strlcpy(mntopts, optarg, sizeof (mntopts));
187 break;
188 case 'h':
189 case '?':
190 if (optopt)
191 (void) fprintf(stderr,
192 gettext("Invalid option '%c'\n"), optopt);
193 (void) fprintf(stderr, gettext("Usage: mount.zfs "
194 "[-sfnvh] [-o options] <dataset> <mountpoint>\n"));
195 return (MOUNT_USAGE);
196 }
197 }
198
199 argc -= optind;
200 argv += optind;
201
202 /* check that we only have two arguments */
203 if (argc != 2) {
204 if (argc == 0)
205 (void) fprintf(stderr, gettext("missing dataset "
206 "argument\n"));
207 else if (argc == 1)
208 (void) fprintf(stderr,
209 gettext("missing mountpoint argument\n"));
210 else
211 (void) fprintf(stderr, gettext("too many arguments\n"));
212 (void) fprintf(stderr, "usage: mount <dataset> <mountpoint>\n");
213 return (MOUNT_USAGE);
214 }
215
216 parse_dataset(argv[0], &pdataset);
217
218 /* canonicalize the mount point */
219 if (realpath(argv[1], mntpoint) == NULL) {
220 (void) fprintf(stderr, gettext("filesystem '%s' cannot be "
221 "mounted at '%s' due to canonicalization error: %s\n"),
222 dataset, argv[1], strerror(errno));
223 return (MOUNT_SYSERR);
224 }
225
226 /* validate mount options and set mntflags */
227 error = zfs_parse_mount_options(mntopts, &mntflags, &zfsflags, sloppy,
228 badopt, mtabopt);
229 if (error) {
230 switch (error) {
231 case ENOMEM:
232 (void) fprintf(stderr, gettext("filesystem '%s' "
233 "cannot be mounted due to a memory allocation "
234 "failure.\n"), dataset);
235 return (MOUNT_SYSERR);
236 case ENOENT:
237 (void) fprintf(stderr, gettext("filesystem '%s' "
238 "cannot be mounted due to invalid option "
239 "'%s'.\n"), dataset, badopt);
240 (void) fprintf(stderr, gettext("Use the '-s' option "
241 "to ignore the bad mount option.\n"));
242 return (MOUNT_USAGE);
243 default:
244 (void) fprintf(stderr, gettext("filesystem '%s' "
245 "cannot be mounted due to internal error %d.\n"),
246 dataset, error);
247 return (MOUNT_SOFTWARE);
248 }
249 }
250
251 if (mntflags & MS_REMOUNT) {
252 nomtab = 1;
253 remount = 1;
254 }
255
256 if (zfsflags & ZS_ZFSUTIL)
257 zfsutil = 1;
258
259 if ((g_zfs = libzfs_init()) == NULL) {
260 (void) fprintf(stderr, "%s\n", libzfs_error_init(errno));
261 return (MOUNT_SYSERR);
262 }
263
264 /* try to open the dataset to access the mount point */
265 if ((zhp = zfs_open(g_zfs, dataset,
266 ZFS_TYPE_FILESYSTEM | ZFS_TYPE_SNAPSHOT)) == NULL) {
267 (void) fprintf(stderr, gettext("filesystem '%s' cannot be "
268 "mounted, unable to open the dataset\n"), dataset);
269 libzfs_fini(g_zfs);
270 return (MOUNT_USAGE);
271 }
272
273 if (sloppy || libzfs_envvar_is_set("ZFS_MOUNT_HELPER")) {
274 zfs_adjust_mount_options(zhp, mntpoint, mntopts, mtabopt);
275 }
276
277 /* treat all snapshots as legacy mount points */
278 if (zfs_get_type(zhp) == ZFS_TYPE_SNAPSHOT)
279 (void) strlcpy(prop, ZFS_MOUNTPOINT_LEGACY, ZFS_MAXPROPLEN);
280 else
281 (void) zfs_prop_get(zhp, ZFS_PROP_MOUNTPOINT, prop,
282 sizeof (prop), NULL, NULL, 0, B_FALSE);
283
284 /*
285 * Fetch the max supported zfs version in case we get ENOTSUP
286 * back from the mount command, since we need the zfs handle
287 * to do so.
288 */
289 zfs_version = zfs_prop_get_int(zhp, ZFS_PROP_VERSION);
290 if (zfs_version == 0) {
291 fprintf(stderr, gettext("unable to fetch "
292 "ZFS version for filesystem '%s'\n"), dataset);
293 zfs_close(zhp);
294 libzfs_fini(g_zfs);
295 return (MOUNT_SYSERR);
296 }
297
298 /*
299 * Legacy mount points may only be mounted using 'mount', never using
300 * 'zfs mount'. However, since 'zfs mount' actually invokes 'mount'
301 * we differentiate the two cases using the 'zfsutil' mount option.
302 * This mount option should only be supplied by the 'zfs mount' util.
303 *
304 * The only exception to the above rule is '-o remount' which is
305 * always allowed for non-legacy datasets. This is done because when
306 * using zfs as your root file system both rc.sysinit/umountroot and
307 * systemd depend on 'mount -o remount <mountpoint>' to work.
308 */
309 if (zfsutil && (strcmp(prop, ZFS_MOUNTPOINT_LEGACY) == 0)) {
310 (void) fprintf(stderr, gettext(
311 "filesystem '%s' cannot be mounted using 'zfs mount'.\n"
312 "Use 'zfs set mountpoint=%s' or 'mount -t zfs %s %s'.\n"
313 "See zfs(8) for more information.\n"),
314 dataset, mntpoint, dataset, mntpoint);
315 zfs_close(zhp);
316 libzfs_fini(g_zfs);
317 return (MOUNT_USAGE);
318 }
319
320 if (!zfsutil && !(remount || fake) &&
321 strcmp(prop, ZFS_MOUNTPOINT_LEGACY)) {
322 (void) fprintf(stderr, gettext(
323 "filesystem '%s' cannot be mounted using 'mount'.\n"
324 "Use 'zfs set mountpoint=%s' or 'zfs mount %s'.\n"
325 "See zfs(8) for more information.\n"),
326 dataset, "legacy", dataset);
327 zfs_close(zhp);
328 libzfs_fini(g_zfs);
329 return (MOUNT_USAGE);
330 }
331
332 if (verbose)
333 (void) fprintf(stdout, gettext("mount.zfs:\n"
334 " dataset: \"%s\"\n mountpoint: \"%s\"\n"
335 " mountflags: 0x%lx\n zfsflags: 0x%lx\n"
336 " mountopts: \"%s\"\n mtabopts: \"%s\"\n"),
337 dataset, mntpoint, mntflags, zfsflags, mntopts, mtabopt);
338
339 if (!fake) {
340 if (!remount && !sloppy &&
341 !libzfs_envvar_is_set("ZFS_MOUNT_HELPER")) {
342 error = zfs_mount_at(zhp, mntopts, mntflags, mntpoint);
343 if (error) {
344 (void) fprintf(stderr, "zfs_mount_at() failed: "
345 "%s", libzfs_error_description(g_zfs));
346 zfs_close(zhp);
347 libzfs_fini(g_zfs);
348 return (MOUNT_SYSERR);
349 }
350 } else {
351 error = mount(dataset, mntpoint, MNTTYPE_ZFS,
352 mntflags, mntopts);
353 }
354 }
355
356 zfs_close(zhp);
357 libzfs_fini(g_zfs);
358
359 if (error) {
360 switch (errno) {
361 case ENOENT:
362 (void) fprintf(stderr, gettext("mount point "
363 "'%s' does not exist\n"), mntpoint);
364 return (MOUNT_SYSERR);
365 case EBUSY:
366 (void) fprintf(stderr, gettext("filesystem "
367 "'%s' is already mounted\n"), dataset);
368 return (MOUNT_BUSY);
369 case ENOTSUP:
370 if (zfs_version > ZPL_VERSION) {
371 (void) fprintf(stderr,
372 gettext("filesystem '%s' (v%d) is not "
373 "supported by this implementation of "
374 "ZFS (max v%d).\n"), dataset,
375 (int)zfs_version, (int)ZPL_VERSION);
376 } else {
377 (void) fprintf(stderr,
378 gettext("filesystem '%s' mount "
379 "failed for unknown reason.\n"), dataset);
380 }
381 return (MOUNT_SYSERR);
382 #ifdef MS_MANDLOCK
383 case EPERM:
384 if (mntflags & MS_MANDLOCK) {
385 (void) fprintf(stderr, gettext("filesystem "
386 "'%s' has the 'nbmand=on' property set, "
387 "this mount\noption may be disabled in "
388 "your kernel. Use 'zfs set nbmand=off'\n"
389 "to disable this option and try to "
390 "mount the filesystem again.\n"), dataset);
391 return (MOUNT_SYSERR);
392 }
393 #endif
394 zfs_fallthrough;
395 default:
396 (void) fprintf(stderr, gettext("filesystem "
397 "'%s' can not be mounted: %s\n"), dataset,
398 strerror(errno));
399 return (MOUNT_USAGE);
400 }
401 }
402
403 if (!nomtab && mtab_is_writeable()) {
404 error = mtab_update(dataset, mntpoint, MNTTYPE_ZFS, mtabopt);
405 if (error)
406 return (error);
407 }
408
409 return (MOUNT_SUCCESS);
410 }
411