[mirror_zfs.git] / lib / libzfs / os / linux / libzfs_mount_os.c

/*
 * 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 2015 Nexenta Systems, Inc.  All rights reserved.
 * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
 * Copyright (c) 2014, 2020 by Delphix. All rights reserved.
 * Copyright 2016 Igor Kozhukhov <ikozhukhov@gmail.com>
 * Copyright 2017 RackTop Systems.
 * Copyright (c) 2018 Datto Inc.
 * Copyright 2018 OmniOS Community Edition (OmniOSce) Association.
 */

#include <dirent.h>
#include <dlfcn.h>
#include <errno.h>
#include <fcntl.h>
#include <libgen.h>
#include <libintl.h>
#include <stdio.h>
#include <stdlib.h>
#include <strings.h>
#include <unistd.h>
#include <zone.h>
#include <sys/mntent.h>
#include <sys/mount.h>
#include <sys/stat.h>
#include <sys/vfs.h>
#include <sys/dsl_crypt.h>
#include <libzfs.h>

#include "libzfs_impl.h"
#include <thread_pool.h>

#define	ZS_COMMENT	0x00000000	/* comment */
#define	ZS_ZFSUTIL	0x00000001	/* caller is zfs(8) */

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_DEVICES,	MS_COMMENT,	ZS_COMMENT	},
	{ MNTOPT_DIRSYNC,	MS_DIRSYNC,	ZS_COMMENT	},
	{ MNTOPT_NOEXEC,	MS_NOEXEC,	ZS_COMMENT	},
	{ MNTOPT_EXEC,		MS_COMMENT,	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_SUID,		MS_COMMENT,	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	},
	/* acl flags passed with util-linux-2.24 mount command */
	{ MNTOPT_ACL,		MS_POSIXACL,	ZS_COMMENT	},
	{ MNTOPT_NOACL,		MS_COMMENT,	ZS_COMMENT	},
	{ MNTOPT_POSIXACL,	MS_POSIXACL,	ZS_COMMENT	},
#ifdef MS_NOATIME
	{ MNTOPT_NOATIME,	MS_NOATIME,	ZS_COMMENT	},
	{ MNTOPT_ATIME,		MS_COMMENT,	ZS_COMMENT	},
#endif
#ifdef MS_NODIRATIME
	{ MNTOPT_NODIRATIME,	MS_NODIRATIME,	ZS_COMMENT	},
	{ MNTOPT_DIRATIME,	MS_COMMENT,	ZS_COMMENT	},
#endif
#ifdef MS_RELATIME
	{ MNTOPT_RELATIME,	MS_RELATIME,	ZS_COMMENT	},
	{ MNTOPT_NORELATIME,	MS_COMMENT,	ZS_COMMENT	},
#endif
#ifdef MS_STRICTATIME
	{ MNTOPT_STRICTATIME,	MS_STRICTATIME,	ZS_COMMENT	},
	{ MNTOPT_NOSTRICTATIME,	MS_COMMENT,	ZS_COMMENT	},
#endif
#ifdef MS_LAZYTIME
	{ MNTOPT_LAZYTIME,	MS_LAZYTIME,	ZS_COMMENT	},
#endif
	{ MNTOPT_CONTEXT,	MS_COMMENT,	ZS_COMMENT	},
	{ MNTOPT_FSCONTEXT,	MS_COMMENT,	ZS_COMMENT	},
	{ MNTOPT_DEFCONTEXT,	MS_COMMENT,	ZS_COMMENT	},
	{ MNTOPT_ROOTCONTEXT,	MS_COMMENT,	ZS_COMMENT	},
#ifdef MS_I_VERSION
	{ MNTOPT_IVERSION,	MS_I_VERSION,	ZS_COMMENT	},
#endif
#ifdef MS_MANDLOCK
	{ MNTOPT_NBMAND,	MS_MANDLOCK,	ZS_COMMENT	},
	{ MNTOPT_NONBMAND,	MS_COMMENT,	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.
 */
int
zfs_parse_mount_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) &&
			    mtabopt != NULL) {
				if (count > 0)
					strlcat(mtabopt, ",", MNT_LINE_MAX);

				strlcat(mtabopt, opt, MNT_LINE_MAX);
				count++;
			}

			opt = NULL;
		}
	}

out:
	free(opts);
	return (error);
}

static void
append_mntopt(const char *name, const char *val, char *mntopts,
    char *mtabopt, boolean_t quote)
{
	char tmp[MNT_LINE_MAX];

	snprintf(tmp, MNT_LINE_MAX, quote ? ",%s=\"%s\"" : ",%s=%s", name, val);

	if (mntopts)
		strlcat(mntopts, tmp, MNT_LINE_MAX);

	if (mtabopt)
		strlcat(mtabopt, tmp, MNT_LINE_MAX);
}

static void
zfs_selinux_setcontext(zfs_handle_t *zhp, zfs_prop_t zpt, const char *name,
    char *mntopts, char *mtabopt)
{
	char context[ZFS_MAXPROPLEN];

	if (zfs_prop_get(zhp, zpt, context, sizeof (context),
	    NULL, NULL, 0, B_FALSE) == 0) {
		if (strcmp(context, "none") != 0)
			append_mntopt(name, context, mntopts, mtabopt, B_TRUE);
	}
}

void
zfs_adjust_mount_options(zfs_handle_t *zhp, const char *mntpoint,
    char *mntopts, char *mtabopt)
{
	char prop[ZFS_MAXPROPLEN];

	/*
	 * Checks to see if the ZFS_PROP_SELINUX_CONTEXT exists
	 * if it does, create a tmp variable in case it's needed
	 * checks to see if the selinux context is set to the default
	 * if it is, allow the setting of the other context properties
	 * this is needed because the 'context' property overrides others
	 * if it is not the default, set the 'context' property
	 */
	if (zfs_prop_get(zhp, ZFS_PROP_SELINUX_CONTEXT, prop, sizeof (prop),
	    NULL, NULL, 0, B_FALSE) == 0) {
		if (strcmp(prop, "none") == 0) {
			zfs_selinux_setcontext(zhp, ZFS_PROP_SELINUX_FSCONTEXT,
			    MNTOPT_FSCONTEXT, mntopts, mtabopt);
			zfs_selinux_setcontext(zhp, ZFS_PROP_SELINUX_DEFCONTEXT,
			    MNTOPT_DEFCONTEXT, mntopts, mtabopt);
			zfs_selinux_setcontext(zhp,
			    ZFS_PROP_SELINUX_ROOTCONTEXT, MNTOPT_ROOTCONTEXT,
			    mntopts, mtabopt);
		} else {
			append_mntopt(MNTOPT_CONTEXT, prop,
			    mntopts, mtabopt, B_TRUE);
		}
	}

	/* A hint used to determine an auto-mounted snapshot mount point */
	append_mntopt(MNTOPT_MNTPOINT, mntpoint, mntopts, NULL, B_FALSE);
}

/*
 * By default the filesystem by preparing the mount options (i.e. parsing
 * some flags from the "opts" parameter into the "flags" parameter) and then
 * directly calling the system call mount(2). We don't need the mount utility
 * or update /etc/mtab, because this is a symlink on all modern systems.
 *
 * If the environment variable ZFS_MOUNT_HELPER is set, we fall back to the
 * previous behavior:
 * The filesystem is mounted by invoking the system mount utility rather
 * than by the system call mount(2).  This ensures that the /etc/mtab
 * file is correctly locked for the update.  Performing our own locking
 * and /etc/mtab update requires making an unsafe assumption about how
 * the mount utility performs its locking.  Unfortunately, this also means
 * in the case of a mount failure we do not have the exact errno.  We must
 * make due with return value from the mount process.
 */
int
do_mount(zfs_handle_t *zhp, const char *mntpt, char *opts, int flags)
{
	const char *src = zfs_get_name(zhp);
	int error = 0;

	if (!libzfs_envvar_is_set("ZFS_MOUNT_HELPER")) {
		char badopt[MNT_LINE_MAX] = {0};
		unsigned long mntflags = flags, zfsflags;
		char myopts[MNT_LINE_MAX] = {0};

		if (zfs_parse_mount_options(opts, &mntflags,
		    &zfsflags, 0, badopt, NULL)) {
			return (EINVAL);
		}
		strlcat(myopts, opts, MNT_LINE_MAX);
		zfs_adjust_mount_options(zhp, mntpt, myopts, NULL);
		if (mount(src, mntpt, MNTTYPE_ZFS, mntflags, myopts)) {
			return (errno);
		}
	} else {
		char *argv[9] = {
		    "/bin/mount",
		    "--no-canonicalize",
		    "-t", MNTTYPE_ZFS,
		    "-o", opts,
		    (char *)src,
		    (char *)mntpt,
		    (char *)NULL };

		/* Return only the most critical mount error */
		error = libzfs_run_process(argv[0], argv,
		    STDOUT_VERBOSE|STDERR_VERBOSE);
		if (error) {
			if (error & MOUNT_FILEIO) {
				error = EIO;
			} else if (error & MOUNT_USER) {
				error = EINTR;
			} else if (error & MOUNT_SOFTWARE) {
				error = EPIPE;
			} else if (error & MOUNT_BUSY) {
				error = EBUSY;
			} else if (error & MOUNT_SYSERR) {
				error = EAGAIN;
			} else if (error & MOUNT_USAGE) {
				error = EINVAL;
			} else
				error = ENXIO; /* Generic error */
		}
	}

	return (error);
}

int
do_unmount(const char *mntpt, int flags)
{
	if (!libzfs_envvar_is_set("ZFS_MOUNT_HELPER")) {
		return (umount2(mntpt, flags));
	}

	char force_opt[] = "-f";
	char lazy_opt[] = "-l";
	char *argv[7] = {
	    "/bin/umount",
	    "-t", MNTTYPE_ZFS,
	    NULL, NULL, NULL, NULL };
	int rc, count = 3;

	if (flags & MS_FORCE) {
		argv[count] = force_opt;
		count++;
	}

	if (flags & MS_DETACH) {
		argv[count] = lazy_opt;
		count++;
	}

	argv[count] = (char *)mntpt;
	rc = libzfs_run_process(argv[0], argv, STDOUT_VERBOSE|STDERR_VERBOSE);

	return (rc ? EINVAL : 0);
}

int
zfs_mount_delegation_check(void)
{
	return ((geteuid() != 0) ? EACCES : 0);
}
Commit	Line	Data
73cdcc63 MM	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 http://www.opensolaris.org/os/licensing.
	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 2015 Nexenta Systems, Inc. All rights reserved.
	24	* Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
c15d36c6	25	* Copyright (c) 2014, 2020 by Delphix. All rights reserved.
73cdcc63 MM	26	* Copyright 2016 Igor Kozhukhov <ikozhukhov@gmail.com>
	27	* Copyright 2017 RackTop Systems.
	28	* Copyright (c) 2018 Datto Inc.
	29	* Copyright 2018 OmniOS Community Edition (OmniOSce) Association.
	30	*/
	31
	32	#include <dirent.h>
	33	#include <dlfcn.h>
	34	#include <errno.h>
	35	#include <fcntl.h>
	36	#include <libgen.h>
	37	#include <libintl.h>
	38	#include <stdio.h>
	39	#include <stdlib.h>
	40	#include <strings.h>
	41	#include <unistd.h>
	42	#include <zone.h>
	43	#include <sys/mntent.h>
	44	#include <sys/mount.h>
	45	#include <sys/stat.h>
	46	#include <sys/vfs.h>
	47	#include <sys/dsl_crypt.h>
	48	#include <libzfs.h>
	49
	50	#include "libzfs_impl.h"
	51	#include <thread_pool.h>
	52
501a1511 FD	53	#define ZS_COMMENT 0x00000000 /* comment */
	54	#define ZS_ZFSUTIL 0x00000001 /* caller is zfs(8) */
	55
	56	typedef struct option_map {
	57	const char *name;
	58	unsigned long mntmask;
	59	unsigned long zfsmask;
	60	} option_map_t;
	61
	62	static const option_map_t option_map[] = {
	63	/* Canonicalized filesystem independent options from mount(8) */
	64	{ MNTOPT_NOAUTO, MS_COMMENT, ZS_COMMENT },
	65	{ MNTOPT_DEFAULTS, MS_COMMENT, ZS_COMMENT },
	66	{ MNTOPT_NODEVICES, MS_NODEV, ZS_COMMENT },
	67	{ MNTOPT_DEVICES, MS_COMMENT, ZS_COMMENT },
	68	{ MNTOPT_DIRSYNC, MS_DIRSYNC, ZS_COMMENT },
	69	{ MNTOPT_NOEXEC, MS_NOEXEC, ZS_COMMENT },
	70	{ MNTOPT_EXEC, MS_COMMENT, ZS_COMMENT },
	71	{ MNTOPT_GROUP, MS_GROUP, ZS_COMMENT },
	72	{ MNTOPT_NETDEV, MS_COMMENT, ZS_COMMENT },
	73	{ MNTOPT_NOFAIL, MS_COMMENT, ZS_COMMENT },
	74	{ MNTOPT_NOSUID, MS_NOSUID, ZS_COMMENT },
	75	{ MNTOPT_SUID, MS_COMMENT, ZS_COMMENT },
	76	{ MNTOPT_OWNER, MS_OWNER, ZS_COMMENT },
	77	{ MNTOPT_REMOUNT, MS_REMOUNT, ZS_COMMENT },
	78	{ MNTOPT_RO, MS_RDONLY, ZS_COMMENT },
	79	{ MNTOPT_RW, MS_COMMENT, ZS_COMMENT },
	80	{ MNTOPT_SYNC, MS_SYNCHRONOUS, ZS_COMMENT },
	81	{ MNTOPT_USER, MS_USERS, ZS_COMMENT },
	82	{ MNTOPT_USERS, MS_USERS, ZS_COMMENT },
	83	/* acl flags passed with util-linux-2.24 mount command */
	84	{ MNTOPT_ACL, MS_POSIXACL, ZS_COMMENT },
	85	{ MNTOPT_NOACL, MS_COMMENT, ZS_COMMENT },
	86	{ MNTOPT_POSIXACL, MS_POSIXACL, ZS_COMMENT },
	87	#ifdef MS_NOATIME
	88	{ MNTOPT_NOATIME, MS_NOATIME, ZS_COMMENT },
	89	{ MNTOPT_ATIME, MS_COMMENT, ZS_COMMENT },
	90	#endif
	91	#ifdef MS_NODIRATIME
	92	{ MNTOPT_NODIRATIME, MS_NODIRATIME, ZS_COMMENT },
	93	{ MNTOPT_DIRATIME, MS_COMMENT, ZS_COMMENT },
	94	#endif
	95	#ifdef MS_RELATIME
	96	{ MNTOPT_RELATIME, MS_RELATIME, ZS_COMMENT },
	97	{ MNTOPT_NORELATIME, MS_COMMENT, ZS_COMMENT },
	98	#endif
	99	#ifdef MS_STRICTATIME
	100	{ MNTOPT_STRICTATIME, MS_STRICTATIME, ZS_COMMENT },
	101	{ MNTOPT_NOSTRICTATIME, MS_COMMENT, ZS_COMMENT },
	102	#endif
	103	#ifdef MS_LAZYTIME
	104	{ MNTOPT_LAZYTIME, MS_LAZYTIME, ZS_COMMENT },
	105	#endif
	106	{ MNTOPT_CONTEXT, MS_COMMENT, ZS_COMMENT },
	107	{ MNTOPT_FSCONTEXT, MS_COMMENT, ZS_COMMENT },
	108	{ MNTOPT_DEFCONTEXT, MS_COMMENT, ZS_COMMENT },
	109	{ MNTOPT_ROOTCONTEXT, MS_COMMENT, ZS_COMMENT },
	110	#ifdef MS_I_VERSION
	111	{ MNTOPT_IVERSION, MS_I_VERSION, ZS_COMMENT },
	112	#endif
	113	#ifdef MS_MANDLOCK
	114	{ MNTOPT_NBMAND, MS_MANDLOCK, ZS_COMMENT },
	115	{ MNTOPT_NONBMAND, MS_COMMENT, ZS_COMMENT },
	116	#endif
117	/* Valid options not found in mount(8) */
118	{ MNTOPT_BIND, MS_BIND, ZS_COMMENT },
119	#ifdef MS_REC
120	{ MNTOPT_RBIND, MS_BIND\|MS_REC, ZS_COMMENT },
121	#endif
122	{ MNTOPT_COMMENT, MS_COMMENT, ZS_COMMENT },
123	#ifdef MS_NOSUB
124	{ MNTOPT_NOSUB, MS_NOSUB, ZS_COMMENT },
125	#endif
126	#ifdef MS_SILENT
127	{ MNTOPT_QUIET, MS_SILENT, ZS_COMMENT },
128	#endif
129	/* Custom zfs options */
130	{ MNTOPT_XATTR, MS_COMMENT, ZS_COMMENT },
131	{ MNTOPT_NOXATTR, MS_COMMENT, ZS_COMMENT },
132	{ MNTOPT_ZFSUTIL, MS_COMMENT, ZS_ZFSUTIL },
133	{ NULL, 0, 0 } };
134
73cdcc63	135	/*
501a1511 FD	136	* Break the mount option in to a name/value pair. The name is
	137	* validated against the option map and mount flags set accordingly.
	138	*/
	139	static int
	140	parse_option(char mntopt, unsigned long mntflags,
	141	unsigned long *zfsflags, int sloppy)
	142	{
	143	const option_map_t *opt;
	144	char ptr, name, *value = NULL;
	145	int error = 0;
	146
	147	name = strdup(mntopt);
	148	if (name == NULL)
	149	return (ENOMEM);
	150
	151	for (ptr = name; ptr && *ptr; ptr++) {
	152	if (*ptr == '=') {
	153	*ptr = '\0';
	154	value = ptr+1;
	155	VERIFY3P(value, !=, NULL);
	156	break;
	157	}
	158	}
	159
	160	for (opt = option_map; opt->name != NULL; opt++) {
	161	if (strncmp(name, opt->name, strlen(name)) == 0) {
	162	*mntflags \|= opt->mntmask;
	163	*zfsflags \|= opt->zfsmask;
	164	error = 0;
	165	goto out;
	166	}
	167	}
	168
	169	if (!sloppy)
	170	error = ENOENT;
	171	out:
	172	/* If required further process on the value may be done here */
	173	free(name);
	174	return (error);
	175	}
	176
	177	/*
	178	* Translate the mount option string in to MS_* mount flags for the
	179	* kernel vfs. When sloppy is non-zero unknown options will be ignored
	180	* otherwise they are considered fatal are copied in to badopt.
	181	*/
	182	int
	183	zfs_parse_mount_options(char mntopts, unsigned long mntflags,
	184	unsigned long zfsflags, int sloppy, char badopt, char *mtabopt)
	185	{
	186	int error = 0, quote = 0, flag = 0, count = 0;
	187	char ptr, opt, *opts;
	188
	189	opts = strdup(mntopts);
	190	if (opts == NULL)
	191	return (ENOMEM);
	192
	193	*mntflags = 0;
	194	opt = NULL;
	195
	196	/*
	197	* Scan through all mount options which must be comma delimited.
	198	* We must be careful to notice regions which are double quoted
	199	* and skip commas in these regions. Each option is then checked
200	* to determine if it is a known option.
201	*/
202	for (ptr = opts; ptr && !flag; ptr++) {
203	if (opt == NULL)
204	opt = ptr;
205
206	if (*ptr == '"')
207	quote = !quote;
208
209	if (quote)
210	continue;
211
212	if (*ptr == '\0')
213	flag = 1;
214
215	if ((ptr == ',') \|\| (ptr == '\0')) {
216	*ptr = '\0';
217
218	error = parse_option(opt, mntflags, zfsflags, sloppy);
219	if (error) {
220	strcpy(badopt, opt);
221	goto out;
222
223	}
224
225	if (!(*mntflags & MS_REMOUNT) &&
226	!(*zfsflags & ZS_ZFSUTIL) &&
227	mtabopt != NULL) {
228	if (count > 0)
229	strlcat(mtabopt, ",", MNT_LINE_MAX);
230
231	strlcat(mtabopt, opt, MNT_LINE_MAX);
232	count++;
233	}
234
235	opt = NULL;
236	}
237	}
238
239	out:
240	free(opts);
241	return (error);
242	}
243
244	static void
245	append_mntopt(const char name, const char val, char *mntopts,
246	char *mtabopt, boolean_t quote)
247	{
248	char tmp[MNT_LINE_MAX];
249
250	snprintf(tmp, MNT_LINE_MAX, quote ? ",%s=\"%s\"" : ",%s=%s", name, val);
251
252	if (mntopts)
253	strlcat(mntopts, tmp, MNT_LINE_MAX);
254
255	if (mtabopt)
256	strlcat(mtabopt, tmp, MNT_LINE_MAX);
257	}
258
259	static void
260	zfs_selinux_setcontext(zfs_handle_t zhp, zfs_prop_t zpt, const char name,
261	char mntopts, char mtabopt)
262	{
263	char context[ZFS_MAXPROPLEN];
264
265	if (zfs_prop_get(zhp, zpt, context, sizeof (context),
266	NULL, NULL, 0, B_FALSE) == 0) {
267	if (strcmp(context, "none") != 0)
268	append_mntopt(name, context, mntopts, mtabopt, B_TRUE);
269	}
270	}
271
272	void
273	zfs_adjust_mount_options(zfs_handle_t zhp, const char mntpoint,
274	char mntopts, char mtabopt)
275	{
276	char prop[ZFS_MAXPROPLEN];
277
278	/*
279	* Checks to see if the ZFS_PROP_SELINUX_CONTEXT exists
280	* if it does, create a tmp variable in case it's needed
281	* checks to see if the selinux context is set to the default
282	* if it is, allow the setting of the other context properties
283	* this is needed because the 'context' property overrides others
284	* if it is not the default, set the 'context' property
285	*/
286	if (zfs_prop_get(zhp, ZFS_PROP_SELINUX_CONTEXT, prop, sizeof (prop),
287	NULL, NULL, 0, B_FALSE) == 0) {
288	if (strcmp(prop, "none") == 0) {
289	zfs_selinux_setcontext(zhp, ZFS_PROP_SELINUX_FSCONTEXT,
290	MNTOPT_FSCONTEXT, mntopts, mtabopt);
291	zfs_selinux_setcontext(zhp, ZFS_PROP_SELINUX_DEFCONTEXT,
292	MNTOPT_DEFCONTEXT, mntopts, mtabopt);
293	zfs_selinux_setcontext(zhp,
294	ZFS_PROP_SELINUX_ROOTCONTEXT, MNTOPT_ROOTCONTEXT,
295	mntopts, mtabopt);
296	} else {
297	append_mntopt(MNTOPT_CONTEXT, prop,
298	mntopts, mtabopt, B_TRUE);
299	}
300	}
301
302	/* A hint used to determine an auto-mounted snapshot mount point */
303	append_mntopt(MNTOPT_MNTPOINT, mntpoint, mntopts, NULL, B_FALSE);
304	}
305
306	/*
307	* By default the filesystem by preparing the mount options (i.e. parsing
308	* some flags from the "opts" parameter into the "flags" parameter) and then
309	* directly calling the system call mount(2). We don't need the mount utility
310	* or update /etc/mtab, because this is a symlink on all modern systems.
311	*
312	* If the environment variable ZFS_MOUNT_HELPER is set, we fall back to the
313	* previous behavior:
73cdcc63 MM	314	* The filesystem is mounted by invoking the system mount utility rather
	315	* than by the system call mount(2). This ensures that the /etc/mtab
	316	* file is correctly locked for the update. Performing our own locking
	317	* and /etc/mtab update requires making an unsafe assumption about how
	318	* the mount utility performs its locking. Unfortunately, this also means
	319	* in the case of a mount failure we do not have the exact errno. We must
	320	* make due with return value from the mount process.
73cdcc63 MM	321	*/
73cdcc63 MM	322	int
501a1511	323	do_mount(zfs_handle_t zhp, const char mntpt, char *opts, int flags)
73cdcc63	324	{
501a1511 FD	325	const char *src = zfs_get_name(zhp);
501a1511 FD	326	int error = 0;
73cdcc63	327
501a1511 FD	328	if (!libzfs_envvar_is_set("ZFS_MOUNT_HELPER")) {
	329	char badopt[MNT_LINE_MAX] = {0};
	330	unsigned long mntflags = flags, zfsflags;
	331	char myopts[MNT_LINE_MAX] = {0};
73cdcc63	332
501a1511 FD	333	if (zfs_parse_mount_options(opts, &mntflags,
	334	&zfsflags, 0, badopt, NULL)) {
	335	return (EINVAL);
	336	}
	337	strlcat(myopts, opts, MNT_LINE_MAX);
	338	zfs_adjust_mount_options(zhp, mntpt, myopts, NULL);
217f4837 RM	339	if (mount(src, mntpt, MNTTYPE_ZFS, mntflags, myopts)) {
	340	return (errno);
	341	}
501a1511 FD	342	} else {
	343	char *argv[9] = {
	344	"/bin/mount",
	345	"--no-canonicalize",
	346	"-t", MNTTYPE_ZFS,
	347	"-o", opts,
	348	(char *)src,
	349	(char *)mntpt,
	350	(char *)NULL };
	351
	352	/* Return only the most critical mount error */
	353	error = libzfs_run_process(argv[0], argv,
	354	STDOUT_VERBOSE\|STDERR_VERBOSE);
	355	if (error) {
	356	if (error & MOUNT_FILEIO) {
	357	error = EIO;
	358	} else if (error & MOUNT_USER) {
	359	error = EINTR;
	360	} else if (error & MOUNT_SOFTWARE) {
	361	error = EPIPE;
	362	} else if (error & MOUNT_BUSY) {
	363	error = EBUSY;
	364	} else if (error & MOUNT_SYSERR) {
	365	error = EAGAIN;
	366	} else if (error & MOUNT_USAGE) {
	367	error = EINVAL;
	368	} else
	369	error = ENXIO; /* Generic error */
	370	}
73cdcc63 MM	371	}
73cdcc63 MM	372
501a1511	373	return (error);
73cdcc63 MM	374	}
	375
	376	int
	377	do_unmount(const char *mntpt, int flags)
	378	{
501a1511 FD	379	if (!libzfs_envvar_is_set("ZFS_MOUNT_HELPER")) {
	380	return (umount2(mntpt, flags));
	381	}
	382
73cdcc63 MM	383	char force_opt[] = "-f";
	384	char lazy_opt[] = "-l";
	385	char *argv[7] = {
	386	"/bin/umount",
	387	"-t", MNTTYPE_ZFS,
	388	NULL, NULL, NULL, NULL };
	389	int rc, count = 3;
	390
	391	if (flags & MS_FORCE) {
	392	argv[count] = force_opt;
	393	count++;
	394	}
	395
	396	if (flags & MS_DETACH) {
	397	argv[count] = lazy_opt;
	398	count++;
	399	}
	400
	401	argv[count] = (char *)mntpt;
	402	rc = libzfs_run_process(argv[0], argv, STDOUT_VERBOSE\|STDERR_VERBOSE);
	403
	404	return (rc ? EINVAL : 0);
	405	}
	406
	407	int
4bc72196	408	zfs_mount_delegation_check(void)
73cdcc63	409	{
4bc72196	410	return ((geteuid() != 0) ? EACCES : 0);
73cdcc63	411	}