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da29fe63f0
mirror_zfs/cmd/mount_zfs/mount_zfs.c
Ned Bass da29fe63f0 Don't leak mount flags into kernel 
When calling mount(), care must be taken to avoid passing in flags
that are used only by the user space utilities.  Otherwise we may
stomp on flags that are reserved for other purposes in the kernel.

In particular, openSUSE 12.3 kernels have added a new MS_RICHACL
super-block flag whose value conflicts with our MS_COMMENT flag. This
causes incorrect behavior such as the umask being ignored.  The
MS_COMMENT flag essentially serves as a placeholder in the option_map
data structure of zfs_mount.c, but its value is never used. Therefore
we can avoid the conflict by defining it to 0.

The MS_USERS, MS_OWNER, and MS_GROUP flags also conflict with reserved
flags in the kernel. While this is not known to have caused any
problems, it is nevertheless incorrect.  For the purposes of the
mount.zfs helper, the "users", "owner", and "group" options just serve
as hints to set additional implied options.  Therefore we now define
their associated mount flags in terms of the options that they imply
rather than giving them unique values.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #1457
2013-06-18 15:30:08 -07:00

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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 */
{ 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);
}
/*
* 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 = 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);
}
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