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zfs/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>
#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 */
{ 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;
break;
}
}
for (opt = option_map; opt->name != NULL; opt++) {
if (strncmp(name, opt->name, strlen(name)) == 0) {
*mntflags |= opt->mntmask;
*zfsflags |= opt->zfsmask;
/* MS_USERS implies default user options */
if (opt->mntmask & (MS_USERS))
*mntflags |= (MS_NOEXEC|MS_NOSUID|MS_NODEV);
/* MS_OWNER|MS_GROUP imply default owner options */
if (opt->mntmask & (MS_OWNER | MS_GROUP))
*mntflags |= (MS_NOSUID|MS_NODEV);
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);
}
/*
* If a file or directory in your current working directory is named
* 'dataset' then mount(8) will prepend your current working directory
* to dataset. The is no way to prevent this behavior so we simply
* check for it and strip the prepended patch when it is added.
*/
static char *
parse_dataset(char *dataset)
{
char cwd[PATH_MAX];
int len;
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 = stat(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 *dataset, *mntpoint;
unsigned long mntflags = 0, zfsflags = 0, remount_ro = 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]);
mntpoint = argv[1];
/* 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;
if ((mntflags & MS_REMOUNT) && (mntflags & MS_RDONLY))
remount_ro = 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)) == NULL) {
(void) fprintf(stderr, gettext("filesystem '%s' cannot be "
"mounted, unable to open the dataset\n"), dataset);
libzfs_fini(g_zfs);
return (MOUNT_USAGE);
}
(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,ro'. This is
* always allowed for non-legacy datasets for rc.sysinit/umountroot
* to safely remount the root filesystem and flush its cache.
*/
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 && strcmp(legacy, ZFS_MOUNTPOINT_LEGACY) && !remount_ro) {
(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 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);
}
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