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