freebsd-nq/cmd/mount_zfs/mount_zfs.c

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/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2011 Lawrence Livermore National Security, LLC.
*/
#include <libintl.h>
#include <unistd.h>
#include <sys/file.h>
#include <sys/mount.h>
#include <sys/stat.h>
#include <libzfs.h>
#include <locale.h>
#ifdef HAVE_LIBSELINUX
#include <selinux/selinux.h>
#endif /* HAVE_LIBSELINUX */
libzfs_handle_t *g_zfs;
typedef struct option_map {
const char *name;
unsigned long mntmask;
unsigned long zfsmask;
} option_map_t;
static const option_map_t option_map[] = {
/* Canonicalized filesystem independent options from mount(8) */
{ MNTOPT_NOAUTO, MS_COMMENT, ZS_COMMENT },
{ MNTOPT_DEFAULTS, MS_COMMENT, ZS_COMMENT },
{ MNTOPT_NODEVICES, MS_NODEV, ZS_COMMENT },
{ MNTOPT_DIRSYNC, MS_DIRSYNC, ZS_COMMENT },
{ MNTOPT_NOEXEC, MS_NOEXEC, ZS_COMMENT },
{ MNTOPT_GROUP, MS_GROUP, ZS_COMMENT },
{ MNTOPT_NETDEV, MS_COMMENT, ZS_COMMENT },
{ MNTOPT_NOFAIL, MS_COMMENT, ZS_COMMENT },
{ MNTOPT_NOSUID, MS_NOSUID, ZS_COMMENT },
{ MNTOPT_OWNER, MS_OWNER, ZS_COMMENT },
{ MNTOPT_REMOUNT, MS_REMOUNT, ZS_COMMENT },
{ MNTOPT_RO, MS_RDONLY, ZS_COMMENT },
{ MNTOPT_RW, MS_COMMENT, ZS_COMMENT },
{ MNTOPT_SYNC, MS_SYNCHRONOUS, ZS_COMMENT },
{ MNTOPT_USER, MS_USERS, ZS_COMMENT },
{ MNTOPT_USERS, MS_USERS, ZS_COMMENT },
#ifdef MS_NOATIME
{ MNTOPT_NOATIME, MS_NOATIME, ZS_COMMENT },
#endif
#ifdef MS_NODIRATIME
{ MNTOPT_NODIRATIME, MS_NODIRATIME, ZS_COMMENT },
#endif
#ifdef MS_RELATIME
{ MNTOPT_RELATIME, MS_RELATIME, ZS_COMMENT },
#endif
#ifdef MS_STRICTATIME
{ MNTOPT_DFRATIME, MS_STRICTATIME, ZS_COMMENT },
#endif
{ MNTOPT_CONTEXT, MS_COMMENT, ZS_NOCONTEXT },
{ MNTOPT_NOCONTEXT, MS_COMMENT, ZS_NOCONTEXT },
{ MNTOPT_FSCONTEXT, MS_COMMENT, ZS_NOCONTEXT },
{ MNTOPT_DEFCONTEXT, MS_COMMENT, ZS_NOCONTEXT },
{ MNTOPT_ROOTCONTEXT, MS_COMMENT, ZS_NOCONTEXT },
#ifdef MS_I_VERSION
{ MNTOPT_IVERSION, MS_I_VERSION, ZS_COMMENT },
#endif
#ifdef MS_MANDLOCK
{ MNTOPT_NBMAND, MS_MANDLOCK, ZS_COMMENT },
#endif
/* Valid options not found in mount(8) */
{ MNTOPT_BIND, MS_BIND, ZS_COMMENT },
#ifdef MS_REC
{ MNTOPT_RBIND, MS_BIND|MS_REC, ZS_COMMENT },
#endif
{ MNTOPT_COMMENT, MS_COMMENT, ZS_COMMENT },
#ifdef MS_NOSUB
{ MNTOPT_NOSUB, MS_NOSUB, ZS_COMMENT },
#endif
#ifdef MS_SILENT
{ MNTOPT_QUIET, MS_SILENT, ZS_COMMENT },
#endif
/* Custom zfs options */
Linux compat 2.6.39: mount_nodev() The .get_sb callback has been replaced by a .mount callback in the file_system_type structure. When using the new interface the caller must now use the mount_nodev() helper. Unfortunately, the new interface no longer passes the vfsmount down to the zfs layers. This poses a problem for the existing implementation because we currently save this pointer in the super block for latter use. It provides our only entry point in to the namespace layer for manipulating certain mount options. This needed to be done originally to allow commands like 'zfs set atime=off tank' to work properly. It also allowed me to keep more of the original Solaris code unmodified. Under Solaris there is a 1-to-1 mapping between a mount point and a file system so this is a fairly natural thing to do. However, under Linux they many be multiple entries in the namespace which reference the same filesystem. Thus keeping a back reference from the filesystem to the namespace is complicated. Rather than introduce some ugly hack to get the vfsmount and continue as before. I'm leveraging this API change to update the ZFS code to do things in a more natural way for Linux. This has the upside that is resolves the compatibility issue for the long term and fixes several other minor bugs which have been reported. This commit updates the code to remove this vfsmount back reference entirely. All modifications to filesystem mount options are now passed in to the kernel via a '-o remount'. This is the expected Linux mechanism and allows the namespace to properly handle any options which apply to it before passing them on to the file system itself. Aside from fixing the compatibility issue, removing the vfsmount has had the benefit of simplifying the code. This change which fairly involved has turned out nicely. Closes #246 Closes #217 Closes #187 Closes #248 Closes #231
2011-05-19 18:44:07 +00:00
{ MNTOPT_XATTR, MS_COMMENT, ZS_COMMENT },
{ MNTOPT_NOXATTR, MS_COMMENT, ZS_COMMENT },
{ MNTOPT_ZFSUTIL, MS_COMMENT, ZS_ZFSUTIL },
{ NULL, 0, 0 } };
/*
* Break the mount option in to a name/value pair. The name is
* validated against the option map and mount flags set accordingly.
*/
static int
parse_option(char *mntopt, unsigned long *mntflags,
unsigned long *zfsflags, int sloppy)
{
const option_map_t *opt;
char *ptr, *name, *value = NULL;
int error = 0;
name = strdup(mntopt);
if (name == NULL)
return (ENOMEM);
for (ptr = name; ptr && *ptr; ptr++) {
if (*ptr == '=') {
*ptr = '\0';
value = ptr+1;
VERIFY3P(value, !=, NULL);
break;
}
}
for (opt = option_map; opt->name != NULL; opt++) {
if (strncmp(name, opt->name, strlen(name)) == 0) {
*mntflags |= opt->mntmask;
*zfsflags |= opt->zfsmask;
error = 0;
goto out;
}
}
if (!sloppy)
error = ENOENT;
out:
/* If required further process on the value may be done here */
free(name);
return (error);
}
/*
* Translate the mount option string in to MS_* mount flags for the
* kernel vfs. When sloppy is non-zero unknown options will be ignored
* otherwise they are considered fatal are copied in to badopt.
*/
static int
parse_options(char *mntopts, unsigned long *mntflags, unsigned long *zfsflags,
int sloppy, char *badopt, char *mtabopt)
{
int error = 0, quote = 0, flag = 0, count = 0;
char *ptr, *opt, *opts;
opts = strdup(mntopts);
if (opts == NULL)
return (ENOMEM);
*mntflags = 0;
opt = NULL;
/*
* Scan through all mount options which must be comma delimited.
* We must be careful to notice regions which are double quoted
* and skip commas in these regions. Each option is then checked
* to determine if it is a known option.
*/
for (ptr = opts; ptr && !flag; ptr++) {
if (opt == NULL)
opt = ptr;
if (*ptr == '"')
quote = !quote;
if (quote)
continue;
if (*ptr == '\0')
flag = 1;
if ((*ptr == ',') || (*ptr == '\0')) {
*ptr = '\0';
error = parse_option(opt, mntflags, zfsflags, sloppy);
if (error) {
strcpy(badopt, opt);
goto out;
}
if (!(*mntflags & MS_REMOUNT) &&
!(*zfsflags & ZS_ZFSUTIL)) {
if (count > 0)
strlcat(mtabopt, ",", MNT_LINE_MAX);
strlcat(mtabopt, opt, MNT_LINE_MAX);
count++;
}
opt = NULL;
}
}
out:
free(opts);
return (error);
}
/*
* Return the pool/dataset to mount given the name passed to mount. This
* is expected to be of the form pool/dataset, however may also refer to
* a block device if that device contains a valid zfs label.
*/
static char *
parse_dataset(char *dataset)
{
char cwd[PATH_MAX];
struct stat64 statbuf;
int error;
int len;
/*
* We expect a pool/dataset to be provided, however if we're
* given a device which is a member of a zpool we attempt to
* extract the pool name stored in the label. Given the pool
* name we can mount the root dataset.
*/
error = stat64(dataset, &statbuf);
if (error == 0) {
nvlist_t *config;
char *name;
int fd;
fd = open(dataset, O_RDONLY);
if (fd < 0)
goto out;
error = zpool_read_label(fd, &config);
(void) close(fd);
if (error)
goto out;
error = nvlist_lookup_string(config,
ZPOOL_CONFIG_POOL_NAME, &name);
if (error == 0)
dataset = strdup(name);
nvlist_free(config);
return (dataset);
}
out:
/*
* If a file or directory in your current working directory is
* named 'dataset' then mount(8) will prepend your current working
* directory to the dataset. There is no way to prevent this
* behavior so we simply check for it and strip the prepended
* patch when it is added.
*/
if (getcwd(cwd, PATH_MAX) == NULL)
return (dataset);
len = strlen(cwd);
/* Do not add one when cwd already ends in a trailing '/' */
if (!strncmp(cwd, dataset, len))
return (dataset + len + (cwd[len-1] != '/'));
return (dataset);
}
/*
* Update the mtab_* code to use the libmount library when it is commonly
* available otherwise fallback to legacy mode. The mount(8) utility will
* manage the lock file for us to prevent racing updates to /etc/mtab.
*/
static int
mtab_is_writeable(void)
{
struct stat st;
int error, fd;
error = lstat(MNTTAB, &st);
if (error || S_ISLNK(st.st_mode))
return (0);
fd = open(MNTTAB, O_RDWR | O_CREAT, 0644);
if (fd < 0)
return (0);
close(fd);
return (1);
}
static int
mtab_update(char *dataset, char *mntpoint, char *type, char *mntopts)
{
struct mntent mnt;
FILE *fp;
int error;
mnt.mnt_fsname = dataset;
mnt.mnt_dir = mntpoint;
mnt.mnt_type = type;
mnt.mnt_opts = mntopts ? mntopts : "";
mnt.mnt_freq = 0;
mnt.mnt_passno = 0;
fp = setmntent(MNTTAB, "a+");
if (!fp) {
(void) fprintf(stderr, gettext(
"filesystem '%s' was mounted, but %s "
"could not be opened due to error %d\n"),
dataset, MNTTAB, errno);
return (MOUNT_FILEIO);
}
error = addmntent(fp, &mnt);
if (error) {
(void) fprintf(stderr, gettext(
"filesystem '%s' was mounted, but %s "
"could not be updated due to error %d\n"),
dataset, MNTTAB, errno);
return (MOUNT_FILEIO);
}
(void) endmntent(fp);
return (MOUNT_SUCCESS);
}
int
main(int argc, char **argv)
{
zfs_handle_t *zhp;
char legacy[ZFS_MAXPROPLEN];
char mntopts[MNT_LINE_MAX] = { '\0' };
char badopt[MNT_LINE_MAX] = { '\0' };
char mtabopt[MNT_LINE_MAX] = { '\0' };
char mntpoint[PATH_MAX];
char *dataset;
unsigned long mntflags = 0, zfsflags = 0, remount = 0;
int sloppy = 0, fake = 0, verbose = 0, nomtab = 0, zfsutil = 0;
int error, c;
(void) setlocale(LC_ALL, "");
(void) textdomain(TEXT_DOMAIN);
opterr = 0;
/* check options */
while ((c = getopt(argc, argv, "sfnvo:h?")) != -1) {
switch (c) {
case 's':
sloppy = 1;
break;
case 'f':
fake = 1;
break;
case 'n':
nomtab = 1;
break;
case 'v':
verbose++;
break;
case 'o':
(void) strlcpy(mntopts, optarg, sizeof (mntopts));
break;
case 'h':
case '?':
(void) fprintf(stderr, gettext("Invalid option '%c'\n"),
optopt);
(void) fprintf(stderr, gettext("Usage: mount.zfs "
"[-sfnv] [-o options] <dataset> <mountpoint>\n"));
return (MOUNT_USAGE);
}
}
argc -= optind;
argv += optind;
/* check that we only have two arguments */
if (argc != 2) {
if (argc == 0)
(void) fprintf(stderr, gettext("missing dataset "
"argument\n"));
else if (argc == 1)
(void) fprintf(stderr,
gettext("missing mountpoint argument\n"));
else
(void) fprintf(stderr, gettext("too many arguments\n"));
(void) fprintf(stderr, "usage: mount <dataset> <mountpoint>\n");
return (MOUNT_USAGE);
}
dataset = parse_dataset(argv[0]);
/* canonicalize the mount point */
if (realpath(argv[1], mntpoint) == NULL) {
(void) fprintf(stderr, gettext("filesystem '%s' cannot be "
"mounted at '%s' due to canonicalization error %d.\n"),
dataset, argv[1], errno);
return (MOUNT_SYSERR);
}
/* validate mount options and set mntflags */
error = parse_options(mntopts, &mntflags, &zfsflags, sloppy,
badopt, mtabopt);
if (error) {
switch (error) {
case ENOMEM:
(void) fprintf(stderr, gettext("filesystem '%s' "
"cannot be mounted due to a memory allocation "
"failure.\n"), dataset);
return (MOUNT_SYSERR);
case ENOENT:
(void) fprintf(stderr, gettext("filesystem '%s' "
"cannot be mounted of due invalid option "
"'%s'.\n"), dataset, badopt);
(void) fprintf(stderr, gettext("Use the '-s' option "
"to ignore the bad mount option.\n"));
return (MOUNT_USAGE);
default:
(void) fprintf(stderr, gettext("filesystem '%s' "
"cannot be mounted due to internal error %d.\n"),
dataset, error);
return (MOUNT_SOFTWARE);
}
}
#ifdef HAVE_LIBSELINUX
/*
* Automatically add the default zfs context when selinux is enabled
* and the caller has not specified their own context. This must be
* done until zfs is added to the default selinux policy configuration
* as a known filesystem type which supports xattrs.
*/
if (is_selinux_enabled() && !(zfsflags & ZS_NOCONTEXT)) {
(void) strlcat(mntopts, ",context=\"system_u:"
"object_r:file_t:s0\"", sizeof (mntopts));
(void) strlcat(mtabopt, ",context=\"system_u:"
"object_r:file_t:s0\"", sizeof (mtabopt));
}
#endif /* HAVE_LIBSELINUX */
if (verbose)
(void) fprintf(stdout, gettext("mount.zfs:\n"
" dataset: \"%s\"\n mountpoint: \"%s\"\n"
" mountflags: 0x%lx\n zfsflags: 0x%lx\n"
" mountopts: \"%s\"\n mtabopts: \"%s\"\n"),
dataset, mntpoint, mntflags, zfsflags, mntopts, mtabopt);
if (mntflags & MS_REMOUNT) {
nomtab = 1;
remount = 1;
}
if (zfsflags & ZS_ZFSUTIL)
zfsutil = 1;
if ((g_zfs = libzfs_init()) == NULL)
return (MOUNT_SYSERR);
/* try to open the dataset to access the mount point */
if ((zhp = zfs_open(g_zfs, dataset,
ZFS_TYPE_FILESYSTEM | ZFS_TYPE_SNAPSHOT)) == NULL) {
(void) fprintf(stderr, gettext("filesystem '%s' cannot be "
"mounted, unable to open the dataset\n"), dataset);
libzfs_fini(g_zfs);
return (MOUNT_USAGE);
}
/* treat all snapshots as legacy mount points */
if (zfs_get_type(zhp) == ZFS_TYPE_SNAPSHOT)
(void) strlcpy(legacy, ZFS_MOUNTPOINT_LEGACY, ZFS_MAXPROPLEN);
else
(void) zfs_prop_get(zhp, ZFS_PROP_MOUNTPOINT, legacy,
sizeof (legacy), NULL, NULL, 0, B_FALSE);
zfs_close(zhp);
libzfs_fini(g_zfs);
/*
* Legacy mount points may only be mounted using 'mount', never using
* 'zfs mount'. However, since 'zfs mount' actually invokes 'mount'
* we differentiate the two cases using the 'zfsutil' mount option.
* This mount option should only be supplied by the 'zfs mount' util.
*
* The only exception to the above rule is '-o remount' which is
* always allowed for non-legacy datasets. This is done because when
* using zfs as your root file system both rc.sysinit/umountroot and
* systemd depend on 'mount -o remount <mountpoint>' to work.
*/
if (zfsutil && !strcmp(legacy, ZFS_MOUNTPOINT_LEGACY)) {
(void) fprintf(stderr, gettext(
"filesystem '%s' cannot be mounted using 'zfs mount'.\n"
"Use 'zfs set mountpoint=%s' or 'mount -t zfs %s %s'.\n"
"See zfs(8) for more information.\n"),
dataset, mntpoint, dataset, mntpoint);
return (MOUNT_USAGE);
}
if (!zfsutil && !(remount || fake) &&
strcmp(legacy, ZFS_MOUNTPOINT_LEGACY)) {
(void) fprintf(stderr, gettext(
"filesystem '%s' cannot be mounted using 'mount'.\n"
"Use 'zfs set mountpoint=%s' or 'zfs mount %s'.\n"
"See zfs(8) for more information.\n"),
dataset, "legacy", dataset);
return (MOUNT_USAGE);
}
if (!fake) {
error = mount(dataset, mntpoint, MNTTYPE_ZFS,
mntflags, mntopts);
if (error) {
switch (errno) {
case ENOENT:
(void) fprintf(stderr, gettext("mount point "
"'%s' does not exist\n"), mntpoint);
return (MOUNT_SYSERR);
case EBUSY:
(void) fprintf(stderr, gettext("filesystem "
"'%s' is already mounted\n"), dataset);
return (MOUNT_SYSERR);
default:
(void) fprintf(stderr, gettext("filesystem "
"'%s' can not be mounted due to error "
"%d\n"), dataset, errno);
return (MOUNT_USAGE);
}
}
}
if (!nomtab && mtab_is_writeable()) {
error = mtab_update(dataset, mntpoint, MNTTYPE_ZFS, mtabopt);
if (error)
return (error);
}
return (MOUNT_SUCCESS);
}