Merge commit '720b16875295d57e0e6a4e0ec32db4d47412f896'

[unleashed.git] / usr / src / lib / libshare / common / libshare_zfs.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 (c) 2006, 2010, Oracle and/or its affiliates. All rights reserved.
 */
/*
 * Copyright 2012 Nexenta Systems, Inc.  All rights reserved.
 * Copyright (c) 2012, 2016 by Delphix. All rights reserved.
 * Copyright 2017 RackTop Systems.
 */

#include <stdio.h>
#include <libzfs.h>
#include <string.h>
#include <strings.h>
#include <errno.h>
#include <libshare.h>
#include "libshare_impl.h"
#include <libintl.h>
#include <sys/mnttab.h>
#include <sys/mntent.h>
#include <assert.h>

extern sa_share_t _sa_add_share(sa_group_t, char *, int, int *, uint64_t);
extern sa_group_t _sa_create_zfs_group(sa_group_t, char *);
extern char *sa_fstype(char *);
extern void set_node_attr(void *, char *, char *);
extern int sa_is_share(void *);
extern void sa_update_sharetab_ts(sa_handle_t);

/*
 * File system specific code for ZFS. The original code was stolen
 * from the "zfs" command and modified to better suit this library's
 * usage.
 */

typedef struct get_all_cbdata {
        zfs_handle_t    **cb_handles;
        size_t          cb_alloc;
        size_t          cb_used;
        uint_t          cb_types;
} get_all_cbdata_t;

/*
 * sa_zfs_init(impl_handle)
 *
 * Initialize an access handle into libzfs.  The handle needs to stay
 * around until sa_zfs_fini() in order to maintain the cache of
 * mounts.
 */

int
sa_zfs_init(sa_handle_impl_t impl_handle)
{
        impl_handle->zfs_libhandle = libzfs_init();
        if (impl_handle->zfs_libhandle != NULL) {
                libzfs_print_on_error(impl_handle->zfs_libhandle, B_TRUE);
                return (B_TRUE);
        }
        return (B_FALSE);
}

/*
 * sa_zfs_fini(impl_handle)
 *
 * cleanup data structures and the libzfs handle used for accessing
 * zfs file share info.
 */

void
sa_zfs_fini(sa_handle_impl_t impl_handle)
{
        if (impl_handle->zfs_libhandle != NULL) {
                if (impl_handle->zfs_list != NULL) {
                        zfs_handle_t **zhp = impl_handle->zfs_list;
                        size_t i;

                        /*
                         * Contents of zfs_list need to be freed so we
                         * don't lose ZFS handles.
                         */
                        for (i = 0; i < impl_handle->zfs_list_count; i++) {
                                zfs_close(zhp[i]);
                        }
                        free(impl_handle->zfs_list);
                        impl_handle->zfs_list = NULL;
                        impl_handle->zfs_list_count = 0;
                }

                libzfs_fini(impl_handle->zfs_libhandle);
                impl_handle->zfs_libhandle = NULL;
        }
}

/*
 * get_one_filesystem(zfs_handle_t, data)
 *
 * an iterator function called while iterating through the ZFS
 * root. It accumulates into an array of file system handles that can
 * be used to derive info about those file systems.
 *
 * Note that as this function is called, we close all zhp handles that
 * are not going to be places into the cp_handles list. We don't want
 * to close the ones we are keeping, but all others would be leaked if
 * not closed here.
 */

static int
get_one_filesystem(zfs_handle_t *zhp, void *data)
{
        get_all_cbdata_t *cbp = data;
        zfs_type_t type = zfs_get_type(zhp);

        /*
         * Interate over any nested datasets.
         */
        if (type == ZFS_TYPE_FILESYSTEM &&
            zfs_iter_filesystems(zhp, get_one_filesystem, data) != 0) {
                zfs_close(zhp);
                return (1);
        }

        /*
         * Skip any datasets whose type does not match.
         */
        if ((type & cbp->cb_types) == 0) {
                zfs_close(zhp);
                return (0);
        }

        if (cbp->cb_alloc == cbp->cb_used) {
                zfs_handle_t **handles;

                if (cbp->cb_alloc == 0)
                        cbp->cb_alloc = 64;
                else
                        cbp->cb_alloc *= 2;

                handles = (zfs_handle_t **)calloc(1,
                    cbp->cb_alloc * sizeof (void *));

                if (handles == NULL) {
                        zfs_close(zhp);
                        return (0);
                }
                if (cbp->cb_handles) {
                        bcopy(cbp->cb_handles, handles,
                            cbp->cb_used * sizeof (void *));
                        free(cbp->cb_handles);
                }

                cbp->cb_handles = handles;
        }

        cbp->cb_handles[cbp->cb_used++] = zhp;

        return (0);
}

/*
 * get_all_filesystems(zfs_handle_t ***fslist, size_t *count)
 *
 * iterate through all ZFS file systems starting at the root. Returns
 * a count and an array of handle pointers. Allocating is only done
 * once. The caller does not need to free since it will be done at
 * sa_zfs_fini() time.
 */

static void
get_all_filesystems(sa_handle_impl_t impl_handle,
    zfs_handle_t ***fslist, size_t *count)
{
        get_all_cbdata_t cb = { 0 };
        cb.cb_types = ZFS_TYPE_FILESYSTEM;

        if (impl_handle->zfs_list != NULL) {
                *fslist = impl_handle->zfs_list;
                *count = impl_handle->zfs_list_count;
                return;
        }

        (void) zfs_iter_root(impl_handle->zfs_libhandle,
            get_one_filesystem, &cb);

        impl_handle->zfs_list = *fslist = cb.cb_handles;
        impl_handle->zfs_list_count = *count = cb.cb_used;
}

/*
 * mountpoint_compare(a, b)
 *
 * compares the mountpoint on two zfs file systems handles.
 * returns values following strcmp() model.
 */

static int
mountpoint_compare(const void *a, const void *b)
{
        zfs_handle_t **za = (zfs_handle_t **)a;
        zfs_handle_t **zb = (zfs_handle_t **)b;
        char mounta[MAXPATHLEN];
        char mountb[MAXPATHLEN];

        verify(zfs_prop_get(*za, ZFS_PROP_MOUNTPOINT, mounta,
            sizeof (mounta), NULL, NULL, 0, B_FALSE) == 0);
        verify(zfs_prop_get(*zb, ZFS_PROP_MOUNTPOINT, mountb,
            sizeof (mountb), NULL, NULL, 0, B_FALSE) == 0);

        return (strcmp(mounta, mountb));
}

/*
 * return legacy mountpoint.  Caller provides space for mountpoint and
 * dataset.
 */
int
get_legacy_mountpoint(const char *path, char *dataset, size_t dlen,
    char *mountpoint, size_t mlen)
{
        FILE *fp;
        struct mnttab entry;

        if ((fp = fopen(MNTTAB, "r")) == NULL) {
                return (1);
        }

        while (getmntent(fp, &entry) == 0) {

                if (entry.mnt_fstype == NULL ||
                    strcmp(entry.mnt_fstype, MNTTYPE_ZFS) != 0)
                        continue;

                if (strcmp(entry.mnt_mountp, path) == 0) {
                        if (mlen > 0)
                                (void) strlcpy(mountpoint, entry.mnt_mountp,
                                    mlen);
                        if (dlen > 0)
                                (void) strlcpy(dataset, entry.mnt_special,
                                    dlen);
                        break;
                }
        }
        (void) fclose(fp);
        return (1);
}


/*
 * Verifies that a specific zfs filesystem handle meets the criteria necessary
 * to be used by libshare operations. See get_zfs_dataset.
 */
static char *
verify_zfs_handle(zfs_handle_t *hdl, const char *path, boolean_t search_mnttab)
{
        char mountpoint[ZFS_MAXPROPLEN];
        char canmount[ZFS_MAXPROPLEN] = { 0 };
        /* must have a mountpoint */
        if (zfs_prop_get(hdl, ZFS_PROP_MOUNTPOINT, mountpoint,
            sizeof (mountpoint), NULL, NULL, 0, B_FALSE) != 0) {
                /* no mountpoint */
                return (NULL);
        }

        /* mountpoint must be a path */
        if (strcmp(mountpoint, ZFS_MOUNTPOINT_NONE) == 0 ||
            strcmp(mountpoint, ZFS_MOUNTPOINT_LEGACY) == 0) {
                /*
                 * Search mmttab for mountpoint and get dataset.
                 */

                if (search_mnttab == B_TRUE &&
                    get_legacy_mountpoint(path, mountpoint,
                    sizeof (mountpoint), NULL, 0) == 0) {
                        return (strdup(mountpoint));
                }
                return (NULL);
        }

        /* canmount must be set */
        if (zfs_prop_get(hdl, ZFS_PROP_CANMOUNT, canmount,
            sizeof (canmount), NULL, NULL, 0, B_FALSE) != 0 ||
            strcmp(canmount, "off") == 0)
                return (NULL);

        /*
         * have a mountable handle but want to skip those marked none
         * and legacy
         */
        if (strcmp(mountpoint, path) == 0) {
                return (strdup((char *)zfs_get_name(hdl)));
        }

        return (NULL);
}

/*
 * get_zfs_dataset(impl_handle, path)
 *
 * get the name of the ZFS dataset the path is equivalent to.  The
 * dataset name is used for get/set of ZFS properties since libzfs
 * requires a dataset to do a zfs_open().
 */

static char *
get_zfs_dataset(sa_handle_impl_t impl_handle, char *path,
    boolean_t search_mnttab)
{
        size_t i, count = 0;
        zfs_handle_t **zlist;
        char *cutpath;
        zfs_handle_t *handle_from_path;
        char *ret = NULL;

        /*
         * First we optimistically assume that the mount path for the filesystem
         * is the same as the name of the filesystem (minus some number of
         * leading slashes). If this is true, then zfs_open should properly open
         * the filesystem. We duplicate the error checking done later in the
         * function for consistency. If anything fails, we resort to the
         * (extremely slow) search of all the filesystems.
         */
        cutpath = path + strspn(path, "/");

        assert(impl_handle->zfs_libhandle != NULL);
        libzfs_print_on_error(impl_handle->zfs_libhandle, B_FALSE);
        handle_from_path = zfs_open(impl_handle->zfs_libhandle, cutpath,
            ZFS_TYPE_FILESYSTEM);
        libzfs_print_on_error(impl_handle->zfs_libhandle, B_TRUE);
        if (handle_from_path != NULL) {
                ret = verify_zfs_handle(handle_from_path, path, search_mnttab);
                zfs_close(handle_from_path);
                if (ret != NULL) {
                        return (ret);
                }
        }
        /*
         * Couldn't find a filesystem optimistically, check all the handles we
         * can.
         */
        get_all_filesystems(impl_handle, &zlist, &count);
        for (i = 0; i < count; i++) {
                assert(zlist[i]);
                if ((ret = verify_zfs_handle(zlist[i], path,
                    search_mnttab)) != NULL)
                        return (ret);
        }

        /* Couldn't find a matching dataset */
        return (NULL);
}

/*
 * get_zfs_property(dataset, property)
 *
 * Get the file system property specified from the ZFS dataset.
 */

static char *
get_zfs_property(char *dataset, zfs_prop_t property)
{
        zfs_handle_t *handle = NULL;
        char shareopts[ZFS_MAXPROPLEN];
        libzfs_handle_t *libhandle;

        libhandle = libzfs_init();
        if (libhandle != NULL) {
                handle = zfs_open(libhandle, dataset, ZFS_TYPE_FILESYSTEM);
                if (handle != NULL) {
                        if (zfs_prop_get(handle, property, shareopts,
                            sizeof (shareopts), NULL, NULL, 0,
                            B_FALSE) == 0) {
                                zfs_close(handle);
                                libzfs_fini(libhandle);
                                return (strdup(shareopts));
                        }
                        zfs_close(handle);
                }
                libzfs_fini(libhandle);
        }
        return (NULL);
}

/*
 * sa_zfs_is_shared(handle, path)
 *
 * Check to see if the ZFS path provided has the sharenfs option set
 * or not.
 */

int
sa_zfs_is_shared(sa_handle_t sahandle, char *path)
{
        int ret = 0;
        char *dataset;
        zfs_handle_t *handle = NULL;
        char shareopts[ZFS_MAXPROPLEN];
        libzfs_handle_t *libhandle;

        dataset = get_zfs_dataset((sa_handle_t)sahandle, path, B_FALSE);
        if (dataset != NULL) {
                libhandle = libzfs_init();
                if (libhandle != NULL) {
                        handle = zfs_open(libhandle, dataset,
                            ZFS_TYPE_FILESYSTEM);
                        if (handle != NULL) {
                                if (zfs_prop_get(handle, ZFS_PROP_SHARENFS,
                                    shareopts, sizeof (shareopts), NULL, NULL,
                                    0, B_FALSE) == 0 &&
                                    strcmp(shareopts, "off") != 0) {
                                        ret = 1; /* it is shared */
                                }
                                zfs_close(handle);
                        }
                        libzfs_fini(libhandle);
                }
                free(dataset);
        }
        return (ret);
}

/*
 * find_or_create_group(handle, groupname, proto, *err)
 *
 * While walking the ZFS tree, we need to add shares to a defined
 * group. If the group doesn't exist, create it first, making sure it
 * is marked as a ZFS group.
 *
 * Note that all ZFS shares are in a subgroup of the top level group
 * called "zfs".
 */

static sa_group_t
find_or_create_group(sa_handle_t handle, char *groupname, char *proto, int *err)
{
        sa_group_t group;
        sa_optionset_t optionset;
        int ret = SA_OK;

        /*
         * we check to see if the "zfs" group exists. Since this
         * should be the top level group, we don't want the
         * parent. This is to make sure the zfs group has been created
         * and to created if it hasn't been.
         */
        group = sa_get_group(handle, groupname);
        if (group == NULL) {
                group = sa_create_group(handle, groupname, &ret);

                /* make sure this is flagged as a ZFS group */
                if (group != NULL)
                        ret = sa_set_group_attr(group, "zfs", "true");
        }
        if (group != NULL) {
                if (proto != NULL) {
                        optionset = sa_get_optionset(group, proto);
                        if (optionset == NULL)
                                optionset = sa_create_optionset(group, proto);
                }
        }
        if (err != NULL)
                *err = ret;
        return (group);
}

/*
 * find_or_create_zfs_subgroup(groupname, optstring, *err)
 *
 * ZFS shares will be in a subgroup of the "zfs" master group.  This
 * function looks to see if the groupname exists and returns it if it
 * does or else creates a new one with the specified name and returns
 * that.  The "zfs" group will exist before we get here, but we make
 * sure just in case.
 *
 * err must be a valid pointer.
 */

static sa_group_t
find_or_create_zfs_subgroup(sa_handle_t handle, char *groupname, char *proto,
    char *optstring, int *err)
{
        sa_group_t group = NULL;
        sa_group_t zfs;
        char *name;
        char *options;

        /* start with the top-level "zfs" group */
        zfs = sa_get_group(handle, "zfs");
        *err = SA_OK;
        if (zfs != NULL) {
                for (group = sa_get_sub_group(zfs); group != NULL;
                    group = sa_get_next_group(group)) {
                        name = sa_get_group_attr(group, "name");
                        if (name != NULL && strcmp(name, groupname) == 0) {
                                /* have the group so break out of here */
                                sa_free_attr_string(name);
                                break;
                        }
                        if (name != NULL)
                                sa_free_attr_string(name);
                }

                if (group == NULL) {
                        /*
                         * Need to create the sub-group since it doesn't exist
                         */
                        group = _sa_create_zfs_group(zfs, groupname);
                        if (group == NULL) {
                                *err = SA_NO_MEMORY;
                                return (NULL);
                        }
                        set_node_attr(group, "zfs", "true");
                }
                if (strcmp(optstring, "on") == 0)
                        optstring = "rw";
                options = strdup(optstring);
                if (options != NULL) {
                        *err = sa_parse_legacy_options(group, options,
                            proto);
                        /* If no optionset, add one. */
                        if (sa_get_optionset(group, proto) == NULL)
                                (void) sa_create_optionset(group, proto);

                        /*
                         * Do not forget to update an optionset of
                         * the parent group so that it contains
                         * all protocols its subgroups have.
                         */
                        if (sa_get_optionset(zfs, proto) == NULL)
                                (void) sa_create_optionset(zfs, proto);

                        free(options);
                } else {
                        *err = SA_NO_MEMORY;
                }
        }
        return (group);
}

/*
 * zfs_construct_resource(share, name, base, dataset)
 *
 * Add a resource to the share using name as a template. If name ==
 * NULL, then construct a name based on the dataset value.
 * name.
 */
static void
zfs_construct_resource(sa_share_t share, char *dataset)
{
        char buff[SA_MAX_RESOURCE_NAME + 1];
        int ret = SA_OK;

        (void) snprintf(buff, SA_MAX_RESOURCE_NAME, "%s", dataset);
        sa_fix_resource_name(buff);
        (void) sa_add_resource(share, buff, SA_SHARE_TRANSIENT, &ret);
}

/*
 * zfs_inherited(handle, source, sourcestr)
 *
 * handle case of inherited share{nfs,smb}. Pulled out of sa_get_zfs_shares
 * for readability.
 */
static int
zfs_inherited(sa_handle_t handle, sa_share_t share, char *sourcestr,
    char *shareopts, char *mountpoint, char *proto, char *dataset)
{
        int doshopt = 0;
        int err = SA_OK;
        sa_group_t group;
        sa_resource_t resource;
        uint64_t features;

        /*
         * Need to find the "real" parent sub-group. It may not be
         * mounted, but it was identified in the "sourcestr"
         * variable. The real parent not mounted can occur if
         * "canmount=off and sharenfs=on".
         */
        group = find_or_create_zfs_subgroup(handle, sourcestr, proto,
            shareopts, &doshopt);
        if (group != NULL) {
                /*
                 * We may need the first share for resource
                 * prototype. We only care about it if it has a
                 * resource that sets a prefix value.
                 */
                if (share == NULL)
                        share = _sa_add_share(group, mountpoint,
                            SA_SHARE_TRANSIENT, &err,
                            (uint64_t)SA_FEATURE_NONE);
                /*
                 * some options may only be on shares. If the opt
                 * string contains one of those, we put it just on the
                 * share.
                 */
                if (share != NULL && doshopt == SA_PROP_SHARE_ONLY) {
                        char *options;
                        options = strdup(shareopts);
                        if (options != NULL) {
                                set_node_attr(share, "dataset", dataset);
                                err = sa_parse_legacy_options(share, options,
                                    proto);
                                set_node_attr(share, "dataset", NULL);
                                free(options);
                        }
                        if (sa_get_optionset(group, proto) == NULL)
                                (void) sa_create_optionset(group, proto);
                }
                features = sa_proto_get_featureset(proto);
                if (share != NULL && features & SA_FEATURE_RESOURCE) {
                        /*
                         * We have a share and the protocol requires
                         * that at least one resource exist (probably
                         * SMB). We need to make sure that there is at
                         * least one.
                         */
                        resource = sa_get_share_resource(share, NULL);
                        if (resource == NULL) {
                                zfs_construct_resource(share, dataset);
                        }
                }
        } else {
                err = SA_NO_MEMORY;
        }
        return (err);
}

/*
 * zfs_notinherited(group, share, mountpoint, shareopts, proto, dataset,
 *     grouperr)
 *
 * handle case where this is the top of a sub-group in ZFS. Pulled out
 * of sa_get_zfs_shares for readability. We need the grouperr from the
 * creation of the subgroup to know whether to add the public
 * property, etc. to the specific share.
 */
static int
zfs_notinherited(sa_group_t group, sa_share_t share, char *mountpoint,
    char *shareopts, char *proto, char *dataset, int grouperr)
{
        int err = SA_OK;
        sa_resource_t resource;
        uint64_t features;

        set_node_attr(group, "zfs", "true");
        if (share == NULL)
                share = _sa_add_share(group, mountpoint, SA_SHARE_TRANSIENT,
                    &err, (uint64_t)SA_FEATURE_NONE);

        if (err != SA_OK)
                return (err);

        if (strcmp(shareopts, "on") == 0)
                shareopts = "";
        if (shareopts != NULL) {
                char *options;
                if (grouperr == SA_PROP_SHARE_ONLY) {
                        /*
                         * Some properties may only be on shares, but
                         * due to the ZFS sub-groups being artificial,
                         * we sometimes get this and have to deal with
                         * it. We do it by attempting to put it on the
                         * share.
                         */
                        options = strdup(shareopts);
                        if (options != NULL) {
                                err = sa_parse_legacy_options(share,
                                    options, proto);
                                free(options);
                        }
                }
                /* Unmark the share's changed state */
                set_node_attr(share, "changed", NULL);
        }
        features = sa_proto_get_featureset(proto);
        if (share != NULL && features & SA_FEATURE_RESOURCE) {
                /*
                 * We have a share and the protocol requires that at
                 * least one resource exist (probably SMB). We need to
                 * make sure that there is at least one.
                 */
                resource = sa_get_share_resource(share, NULL);
                if (resource == NULL) {
                        zfs_construct_resource(share, dataset);
                }
        }
        return (err);
}

/*
 * zfs_grp_error(err)
 *
 * Print group create error, but only once. If err is 0 do the
 * print else don't.
 */

static void
zfs_grp_error(int err)
{
        if (err == 0) {
                /* only print error once */
                (void) fprintf(stderr, dgettext(TEXT_DOMAIN,
                    "Cannot create ZFS subgroup during initialization:"
                    " %s\n"), sa_errorstr(SA_SYSTEM_ERR));
        }
}

/*
 * zfs_process_share(handle, share, mountpoint, proto, source,
 *     shareopts, sourcestr)
 *
 * Creates the subgroup, if necessary and adds shares, resources
 * and properties.
 */
int
sa_zfs_process_share(sa_handle_t handle, sa_group_t group, sa_share_t share,
    char *mountpoint, char *proto, zprop_source_t source, char *shareopts,
    char *sourcestr, char *dataset)
{
        int err = SA_OK;

        if (source & ZPROP_SRC_INHERITED) {
                err = zfs_inherited(handle, share, sourcestr, shareopts,
                    mountpoint, proto, dataset);
        } else {
                group = find_or_create_zfs_subgroup(handle, dataset, proto,
                    shareopts, &err);
                if (group == NULL) {
                        static boolean_t reported_error = B_FALSE;
                        /*
                         * There is a problem, but we can't do
                         * anything about it at this point so we issue
                         * a warning and move on.
                         */
                        zfs_grp_error(reported_error);
                        reported_error = B_TRUE;
                }
                set_node_attr(group, "zfs", "true");
                /*
                 * Add share with local opts via zfs_notinherited.
                 */
                err = zfs_notinherited(group, share, mountpoint, shareopts,
                    proto, dataset, err);
        }
        return (err);
}

/*
 * Walk the mnttab for all zfs mounts and determine which are
 * shared. Find or create the appropriate group/sub-group to contain
 * the shares.
 *
 * All shares are in a sub-group that will hold the properties. This
 * allows representing the inherited property model.
 *
 * One area of complication is if "sharenfs" is set at one level of
 * the directory tree and "sharesmb" is set at a different level, the
 * a sub-group must be formed at the lower level for both
 * protocols. That is the nature of the problem in CR 6667349.
 */
static int
sa_get_zfs_share_common(sa_handle_t handle, zfs_handle_t *fs_handle, char *path,
    sa_group_t zfsgroup)
{
        boolean_t smb, nfs;
        boolean_t smb_inherited, nfs_inherited;
        char nfsshareopts[ZFS_MAXPROPLEN];
        char smbshareopts[ZFS_MAXPROPLEN];
        char nfssourcestr[ZFS_MAXPROPLEN];
        char smbsourcestr[ZFS_MAXPROPLEN];
        char mountpoint[ZFS_MAXPROPLEN];
        int err = SA_OK;
        zprop_source_t source;
        sa_share_t share;
        char *dataset;

        source = ZPROP_SRC_ALL;
        /* If no mountpoint, skip. */
        if (zfs_prop_get(fs_handle, ZFS_PROP_MOUNTPOINT,
            mountpoint, sizeof (mountpoint), NULL, NULL, 0,
            B_FALSE) != 0)
                return (SA_SYSTEM_ERR);

        if (path != NULL)
                (void) strncpy(path, mountpoint, sizeof (mountpoint));
        /*
         * zfs_get_name value must not be freed. It is just a
         * pointer to a value in the handle.
         */
        if ((dataset = (char *)zfs_get_name(fs_handle)) == NULL)
                return (SA_SYSTEM_ERR);

        /*
         * only deal with "mounted" file systems since
         * unmounted file systems can't actually be shared.
         */

        if (!zfs_is_mounted(fs_handle, NULL))
                return (SA_SYSTEM_ERR);

        nfs = nfs_inherited = B_FALSE;

        if (zfs_prop_get(fs_handle, ZFS_PROP_SHARENFS, nfsshareopts,
            sizeof (nfsshareopts), &source, nfssourcestr,
            ZFS_MAXPROPLEN, B_FALSE) == 0 &&
            strcmp(nfsshareopts, "off") != 0) {
                if (source & ZPROP_SRC_INHERITED)
                        nfs_inherited = B_TRUE;
                else
                        nfs = B_TRUE;
        }

        smb = smb_inherited = B_FALSE;
        if (zfs_prop_get(fs_handle, ZFS_PROP_SHARESMB, smbshareopts,
            sizeof (smbshareopts), &source, smbsourcestr,
            ZFS_MAXPROPLEN, B_FALSE) == 0 &&
            strcmp(smbshareopts, "off") != 0) {
                if (source & ZPROP_SRC_INHERITED)
                        smb_inherited = B_TRUE;
                else
                        smb = B_TRUE;
        }

        /*
         * If the mountpoint is already shared, it must be a
         * non-ZFS share. We want to remove the share from its
         * parent group and reshare it under ZFS.
         */
        share = sa_find_share(handle, mountpoint);
        if (share != NULL &&
            (nfs || smb || nfs_inherited || smb_inherited)) {
                err = sa_remove_share(share);
                share = NULL;
        }

        /*
         * At this point, we have the information needed to
         * determine what to do with the share.
         *
         * If smb or nfs is set, we have a new sub-group.
         * If smb_inherit and/or nfs_inherit is set, then
         * place on an existing sub-group. If both are set,
         * the existing sub-group is the closest up the tree.
         */
        if (nfs || smb) {
                /*
                 * Non-inherited is the straightforward
                 * case. sa_zfs_process_share handles it
                 * directly. Make sure that if the "other"
                 * protocol is inherited, that we treat it as
                 * non-inherited as well.
                 */
                if (nfs || nfs_inherited) {
                        err = sa_zfs_process_share(handle, zfsgroup,
                            share, mountpoint, "nfs",
                            0, nfsshareopts,
                            nfssourcestr, dataset);
                        share = sa_find_share(handle, mountpoint);
                }
                if (smb || smb_inherited) {
                        err = sa_zfs_process_share(handle, zfsgroup,
                            share, mountpoint, "smb",
                            0, smbshareopts,
                            smbsourcestr, dataset);
                }
        } else if (nfs_inherited || smb_inherited) {
                char *grpdataset;
                /*
                 * If we only have inherited groups, it is
                 * important to find the closer of the two if
                 * the protocols are set at different
                 * levels. The closest sub-group is the one we
                 * want to work with.
                 */
                if (nfs_inherited && smb_inherited) {
                        if (strcmp(nfssourcestr, smbsourcestr) <= 0)
                                grpdataset = nfssourcestr;
                        else
                                grpdataset = smbsourcestr;
                } else if (nfs_inherited) {
                        grpdataset = nfssourcestr;
                } else if (smb_inherited) {
                        grpdataset = smbsourcestr;
                }
                if (nfs_inherited) {
                        err = sa_zfs_process_share(handle, zfsgroup,
                            share, mountpoint, "nfs",
                            ZPROP_SRC_INHERITED, nfsshareopts,
                            grpdataset, dataset);
                        share = sa_find_share(handle, mountpoint);
                }
                if (smb_inherited) {
                        err = sa_zfs_process_share(handle, zfsgroup,
                            share, mountpoint, "smb",
                            ZPROP_SRC_INHERITED, smbshareopts,
                            grpdataset, dataset);
                }
        }
        return (err);
}

/*
 * Handles preparing generic objects such as the libzfs handle and group for
 * sa_get_one_zfs_share, sa_get_zfs_share_for_name, and sa_get_zfs_shares.
 */
static int
prep_zfs_handle_and_group(sa_handle_t handle, char *groupname,
    libzfs_handle_t **zfs_libhandle, sa_group_t *zfsgroup, int *err)
{
        /*
         * If we can't access libzfs, don't bother doing anything.
         */
        *zfs_libhandle = ((sa_handle_impl_t)handle)->zfs_libhandle;
        if (*zfs_libhandle == NULL)
                return (SA_SYSTEM_ERR);

        *zfsgroup = find_or_create_group(handle, groupname, NULL, err);
        return (SA_OK);
}

/*
 * The O.G. zfs share preparation function. This initializes all zfs shares for
 * use with libshare.
 */
int
sa_get_zfs_shares(sa_handle_t handle, char *groupname)
{
        sa_group_t zfsgroup;
        zfs_handle_t **zlist;
        size_t count = 0;
        libzfs_handle_t *zfs_libhandle;
        int err;

        if ((err = prep_zfs_handle_and_group(handle, groupname, &zfs_libhandle,
            &zfsgroup, &err)) != SA_OK) {
                return (err);
        }
        /* Not an error, this could be a legacy condition */
        if (zfsgroup == NULL)
                return (SA_OK);

        /*
         * need to walk the mounted ZFS pools and datasets to
         * find shares that are possible.
         */
        get_all_filesystems((sa_handle_impl_t)handle, &zlist, &count);
        qsort(zlist, count, sizeof (void *), mountpoint_compare);

        for (int i = 0; i < count; i++) {
                err = sa_get_zfs_share_common(handle, zlist[i], NULL, zfsgroup);
        }
        /*
         * Don't need to free the "zlist" variable since it is only a
         * pointer to a cached value that will be freed when
         * sa_fini() is called.
         */
        return (err);
}

/*
 * Initializes only the handles specified in the sharearg for use with libshare.
 * This is used as a performance optimization relative to sa_get_zfs_shares.
 */
int
sa_get_one_zfs_share(sa_handle_t handle, char *groupname,
    sa_init_selective_arg_t *sharearg, char ***paths, size_t *paths_len)
{
        sa_group_t zfsgroup;
        libzfs_handle_t *zfs_libhandle;
        int err;

        if ((err = prep_zfs_handle_and_group(handle, groupname, &zfs_libhandle,
            &zfsgroup, &err)) != SA_OK) {
                return (err);
        }
        /* Not an error, this could be a legacy condition */
        if (zfsgroup == NULL)
                return (SA_OK);

        *paths_len = sharearg->zhandle_len;
        *paths = calloc(*paths_len, sizeof (char *));
        for (int i = 0; i < sharearg->zhandle_len; ++i) {
                zfs_handle_t *fs_handle =
                    ((zfs_handle_t **)(sharearg->zhandle_arr))[i];
                if (fs_handle == NULL) {
                        /* Free non-null elements of the paths array */
                        for (int free_idx = 0; free_idx < *paths_len;
                            ++free_idx) {
                                if ((*paths)[free_idx] != NULL)
                                        free((*paths)[free_idx]);
                        }
                        free(*paths);
                        *paths = NULL;
                        *paths_len = 0;
                        return (SA_SYSTEM_ERR);
                }
                (*paths)[i] = malloc(sizeof (char) * ZFS_MAXPROPLEN);
                err |= sa_get_zfs_share_common(handle, fs_handle, (*paths)[i],
                    zfsgroup);
        }

        return (err);
}

/*
 * Initializes only the share with the specified sharename for use with
 * libshare.
 */
int
sa_get_zfs_share_for_name(sa_handle_t handle, char *groupname,
    const char *sharename, char *outpath)
{
        sa_group_t zfsgroup;
        libzfs_handle_t *zfs_libhandle;
        int err;

        if ((err = prep_zfs_handle_and_group(handle, groupname, &zfs_libhandle,
            &zfsgroup, &err)) != SA_OK) {
                return (err);
        }
        /* Not an error, this could be a legacy condition */
        if (zfsgroup == NULL)
                return (SA_OK);

        zfs_handle_t *fs_handle = zfs_open(zfs_libhandle,
            sharename + strspn(sharename, "/"), ZFS_TYPE_DATASET);
        if (fs_handle == NULL)
                return (SA_SYSTEM_ERR);

        err = sa_get_zfs_share_common(handle, fs_handle, outpath, zfsgroup);
        zfs_close(fs_handle);
        return (err);
}



#define COMMAND         "/usr/sbin/zfs"

/*
 * sa_zfs_set_sharenfs(group, path, on)
 *
 * Update the "sharenfs" property on the path. If on is true, then set
 * to the properties on the group or "on" if no properties are
 * defined. Set to "off" if on is false.
 */

int
sa_zfs_set_sharenfs(sa_group_t group, char *path, int on)
{
        int ret = SA_NOT_IMPLEMENTED;
        char *command;

        command = malloc(ZFS_MAXPROPLEN * 2);
        if (command != NULL) {
                char *opts = NULL;
                char *dataset = NULL;
                FILE *pfile;
                sa_handle_impl_t impl_handle;
                /* for now, NFS is always available for "zfs" */
                if (on) {
                        opts = sa_proto_legacy_format("nfs", group, 1);
                        if (opts != NULL && strlen(opts) == 0) {
                                free(opts);
                                opts = strdup("on");
                        }
                }

                impl_handle = (sa_handle_impl_t)sa_find_group_handle(group);
                assert(impl_handle != NULL);
                if (impl_handle != NULL)
                        dataset = get_zfs_dataset(impl_handle, path, B_FALSE);
                else
                        ret = SA_SYSTEM_ERR;

                if (dataset != NULL) {
                        (void) snprintf(command, ZFS_MAXPROPLEN * 2,
                            "%s set sharenfs=\"%s\" %s", COMMAND,
                            opts != NULL ? opts : "off", dataset);
                        pfile = popen(command, "r");
                        if (pfile != NULL) {
                                ret = pclose(pfile);
                                if (ret != 0)
                                        ret = SA_SYSTEM_ERR;
                        }
                }
                free(opts);
                free(dataset);
                free(command);
        }
        return (ret);
}

/*
 * add_resources(share, opt)
 *
 * Add resource properties to those in "opt".  Resources are prefixed
 * with name=resourcename.
 */
static char *
add_resources(sa_share_t share, char *opt)
{
        char *newopt = NULL;
        char *propstr;
        sa_resource_t resource;

        newopt = strdup(opt);
        if (newopt == NULL)
                return (newopt);

        for (resource = sa_get_share_resource(share, NULL);
            resource != NULL;
            resource = sa_get_next_resource(resource)) {
                char *name;
                size_t size;

                name = sa_get_resource_attr(resource, "name");
                if (name == NULL) {
                        free(newopt);
                        return (NULL);
                }
                size = strlen(name) + strlen(opt) + sizeof ("name=") + 1;
                newopt = calloc(1, size);
                if (newopt != NULL)
                        (void) snprintf(newopt, size, "%s,name=%s", opt, name);
                sa_free_attr_string(name);
                free(opt);
                opt = newopt;
                propstr = sa_proto_legacy_format("smb", resource, 0);
                if (propstr == NULL) {
                        free(opt);
                        return (NULL);
                }
                size = strlen(propstr) + strlen(opt) + 2;
                newopt = calloc(1, size);
                if (newopt != NULL)
                        (void) snprintf(newopt, size, "%s,%s", opt, propstr);
                free(opt);
                opt = newopt;
        }
        return (opt);
}

/*
 * sa_zfs_set_sharesmb(group, path, on)
 *
 * Update the "sharesmb" property on the path. If on is true, then set
 * to the properties on the group or "on" if no properties are
 * defined. Set to "off" if on is false.
 */

int
sa_zfs_set_sharesmb(sa_group_t group, char *path, int on)
{
        int ret = SA_NOT_IMPLEMENTED;
        char *command;
        sa_share_t share;

        /* In case SMB not enabled */
        if (sa_get_optionset(group, "smb") == NULL)
                return (SA_NOT_SUPPORTED);

        command = malloc(ZFS_MAXPROPLEN * 2);
        if (command != NULL) {
                char *opts = NULL;
                char *dataset = NULL;
                FILE *pfile;
                sa_handle_impl_t impl_handle;

                if (on) {
                        char *newopt;

                        share = sa_get_share(group, NULL);
                        opts = sa_proto_legacy_format("smb", share, 1);
                        if (opts != NULL && strlen(opts) == 0) {
                                free(opts);
                                opts = strdup("on");
                        }
                        newopt = add_resources(opts, share);
                        free(opts);
                        opts = newopt;
                }

                impl_handle = (sa_handle_impl_t)sa_find_group_handle(group);
                assert(impl_handle != NULL);
                if (impl_handle != NULL)
                        dataset = get_zfs_dataset(impl_handle, path, B_FALSE);
                else
                        ret = SA_SYSTEM_ERR;

                if (dataset != NULL) {
                        (void) snprintf(command, ZFS_MAXPROPLEN * 2,
                            "echo %s set sharesmb=\"%s\" %s", COMMAND,
                            opts != NULL ? opts : "off", dataset);
                        pfile = popen(command, "r");
                        if (pfile != NULL) {
                                ret = pclose(pfile);
                                if (ret != 0)
                                        ret = SA_SYSTEM_ERR;
                        }
                }
                free(opts);
                free(dataset);
                free(command);
        }
        return (ret);
}

/*
 * sa_zfs_update(group)
 *
 * call back to ZFS to update the share if necessary.
 * Don't do it if it isn't a real change.
 */
int
sa_zfs_update(sa_group_t group)
{
        sa_optionset_t protopt;
        sa_group_t parent;
        char *command;
        char *optstring;
        int ret = SA_OK;
        int doupdate = 0;
        FILE *pfile;

        if (sa_is_share(group))
                parent = sa_get_parent_group(group);
        else
                parent = group;

        if (parent != NULL) {
                command = malloc(ZFS_MAXPROPLEN * 2);
                if (command == NULL)
                        return (SA_NO_MEMORY);

                *command = '\0';
                for (protopt = sa_get_optionset(parent, NULL); protopt != NULL;
                    protopt = sa_get_next_optionset(protopt)) {

                        char *proto = sa_get_optionset_attr(protopt, "type");
                        char *path;
                        char *dataset = NULL;
                        char *zfsopts = NULL;

                        if (sa_is_share(group)) {
                                path = sa_get_share_attr((sa_share_t)group,
                                    "path");
                                if (path != NULL) {
                                        sa_handle_impl_t impl_handle;

                                        impl_handle = sa_find_group_handle(
                                            group);
                                        if (impl_handle != NULL)
                                                dataset = get_zfs_dataset(
                                                    impl_handle, path, B_FALSE);
                                        else
                                                ret = SA_SYSTEM_ERR;

                                        sa_free_attr_string(path);
                                }
                        } else {
                                dataset = sa_get_group_attr(group, "name");
                        }
                        /* update only when there is an optstring found */
                        doupdate = 0;
                        if (proto != NULL && dataset != NULL) {
                                optstring = sa_proto_legacy_format(proto,
                                    group, 1);
                                zfsopts = get_zfs_property(dataset,
                                    ZFS_PROP_SHARENFS);

                                if (optstring != NULL && zfsopts != NULL) {
                                        if (strcmp(optstring, zfsopts) != 0)
                                                doupdate++;
                                }
                                if (doupdate) {
                                        if (optstring != NULL &&
                                            strlen(optstring) > 0) {
                                                (void) snprintf(command,
                                                    ZFS_MAXPROPLEN * 2,
                                                    "%s set share%s=%s %s",
                                                    COMMAND, proto,
                                                    optstring, dataset);
                                        } else {
                                                (void) snprintf(command,
                                                    ZFS_MAXPROPLEN * 2,
                                                    "%s set share%s=on %s",
                                                    COMMAND, proto,
                                                    dataset);
                                        }
                                        pfile = popen(command, "r");
                                        if (pfile != NULL)
                                                ret = pclose(pfile);
                                        switch (ret) {
                                        default:
                                        case 1:
                                                ret = SA_SYSTEM_ERR;
                                                break;
                                        case 2:
                                                ret = SA_SYNTAX_ERR;
                                                break;
                                        case 0:
                                                break;
                                        }
                                }
                                free(optstring);
                                free(zfsopts);
                        }
                        if (proto != NULL)
                                sa_free_attr_string(proto);
                        free(dataset);
                }
                free(command);
        }
        return (ret);
}

/*
 * sa_group_is_zfs(group)
 *
 * Given the group, determine if the zfs attribute is set.
 */

int
sa_group_is_zfs(sa_group_t group)
{
        char *zfs;
        int ret = 0;

        zfs = sa_get_group_attr(group, "zfs");
        if (zfs != NULL) {
                ret = 1;
                sa_free_attr_string(zfs);
        }
        return (ret);
}

/*
 * sa_path_is_zfs(path)
 *
 * Check to see if the file system path represents is of type "zfs".
 */

int
sa_path_is_zfs(char *path)
{
        char *fstype;
        int ret = 0;

        fstype = sa_fstype(path);
        if (fstype != NULL && strcmp(fstype, "zfs") == 0)
                ret = 1;
        if (fstype != NULL)
                sa_free_fstype(fstype);
        return (ret);
}

int
sa_sharetab_fill_zfs(sa_share_t share, share_t *sh, char *proto)
{
        char *path;

        /* Make sure path is valid */

        path = sa_get_share_attr(share, "path");
        if (path != NULL) {
                (void) memset(sh, 0, sizeof (sh));
                (void) sa_fillshare(share, proto, sh);
                sa_free_attr_string(path);
                return (0);
        } else
                return (1);
}

#define SMAX(i, j)      \
        if ((j) > (i)) { \
                (i) = (j); \
        }

int
sa_share_zfs(sa_share_t share, sa_resource_t resource, char *path, share_t *sh,
    void *exportdata, zfs_share_op_t operation)
{
        libzfs_handle_t *libhandle;
        sa_group_t group;
        sa_handle_t sahandle;
        char *dataset;
        int err = EINVAL;
        int i, j;
        char newpath[MAXPATHLEN];
        char *pathp;

        /*
         * First find the dataset name
         */
        if ((group = sa_get_parent_group(share)) == NULL)  {
                return (EINVAL);
        }
        if ((sahandle = sa_find_group_handle(group)) == NULL) {
                return (EINVAL);
        }

        /*
         * If get_zfs_dataset fails, see if it is a subdirectory
         */

        pathp = path;
        while ((dataset = get_zfs_dataset(sahandle, pathp, B_TRUE)) == NULL) {
                char *p;

                if (pathp == path) {
                        (void) strlcpy(newpath, path, sizeof (newpath));
                        pathp = newpath;
                }

                /*
                 * Make sure only one leading '/' This condition came
                 * about when using HAStoragePlus which insisted on
                 * putting an extra leading '/' in the ZFS path
                 * name. The problem is fixed in other areas, but this
                 * will catch any other ways that a double slash might
                 * get introduced.
                 */
                while (*pathp == '/' && *(pathp + 1) == '/')
                        pathp++;

                /*
                 * chop off part of path, but if we are at root then
                 * make sure path is a /
                 */
                if ((strlen(pathp) > 1) && (p = strrchr(pathp, '/'))) {
                        if (pathp == p) {
                                *(p + 1) = '\0';  /* skip over /, root case */
                        } else {
                                *p = '\0';
                        }
                } else {
                        return (EINVAL);
                }
        }

        libhandle = libzfs_init();
        if (libhandle != NULL) {
                char *resource_name;

                i = (sh->sh_path ? strlen(sh->sh_path) : 0);
                sh->sh_size = i;

                j = (sh->sh_res ? strlen(sh->sh_res) : 0);
                sh->sh_size += j;
                SMAX(i, j);

                j = (sh->sh_fstype ? strlen(sh->sh_fstype) : 0);
                sh->sh_size += j;
                SMAX(i, j);

                j = (sh->sh_opts ? strlen(sh->sh_opts) : 0);
                sh->sh_size += j;
                SMAX(i, j);

                j = (sh->sh_descr ? strlen(sh->sh_descr) : 0);
                sh->sh_size += j;
                SMAX(i, j);

                resource_name = sa_get_resource_attr(resource, "name");

                err = zfs_deleg_share_nfs(libhandle, dataset, path,
                    resource_name, exportdata, sh, i, operation);
                if (err == SA_OK)
                        sa_update_sharetab_ts(sahandle);
                else
                        err = errno;
                if (resource_name)
                        sa_free_attr_string(resource_name);

                libzfs_fini(libhandle);
        }
        free(dataset);
        return (err);
}

/*
 * sa_get_zfs_handle(handle)
 *
 * Given an sa_handle_t, return the libzfs_handle_t *. This is only
 * used internally by libzfs. Needed in order to avoid including
 * libshare_impl.h in libzfs.
 */

libzfs_handle_t *
sa_get_zfs_handle(sa_handle_t handle)
{
        sa_handle_impl_t implhandle = (sa_handle_impl_t)handle;

        return (implhandle->zfs_libhandle);
}

/*
 * sa_get_zfs_info(libzfs, path, mountpoint, dataset)
 *
 * Find the ZFS dataset and mountpoint for a given path
 */
int
sa_zfs_get_info(libzfs_handle_t *libzfs, char *path, char *mountpointp,
    char *datasetp)
{
        get_all_cbdata_t cb = { 0 };
        int i;
        char mountpoint[ZFS_MAXPROPLEN];
        char dataset[ZFS_MAXPROPLEN];
        char canmount[ZFS_MAXPROPLEN];
        char *dp;
        int count;
        int ret = 0;

        cb.cb_types = ZFS_TYPE_FILESYSTEM;

        if (libzfs == NULL)
                return (0);

        (void) zfs_iter_root(libzfs, get_one_filesystem, &cb);
        count = cb.cb_used;

        qsort(cb.cb_handles, count, sizeof (void *), mountpoint_compare);
        for (i = 0; i < count; i++) {
                /* must have a mountpoint */
                if (zfs_prop_get(cb.cb_handles[i], ZFS_PROP_MOUNTPOINT,
                    mountpoint, sizeof (mountpoint),
                    NULL, NULL, 0, B_FALSE) != 0) {
                        /* no mountpoint */
                        continue;
                }

                /* mountpoint must be a path */
                if (strcmp(mountpoint, ZFS_MOUNTPOINT_NONE) == 0 ||
                    strcmp(mountpoint, ZFS_MOUNTPOINT_LEGACY) == 0) {
                        /*
                         * Search mmttab for mountpoint
                         */

                        if (get_legacy_mountpoint(path, dataset,
                            ZFS_MAXPROPLEN, mountpoint,
                            ZFS_MAXPROPLEN) == 0) {
                                ret = 1;
                                break;
                        }
                        continue;
                }

                /* canmount must be set */
                canmount[0] = '\0';
                if (zfs_prop_get(cb.cb_handles[i], ZFS_PROP_CANMOUNT, canmount,
                    sizeof (canmount), NULL, NULL, 0, B_FALSE) != 0 ||
                    strcmp(canmount, "off") == 0)
                        continue;

                /*
                 * have a mountable handle but want to skip those marked none
                 * and legacy
                 */
                if (strcmp(mountpoint, path) == 0) {
                        dp = (char *)zfs_get_name(cb.cb_handles[i]);
                        if (dp != NULL) {
                                if (datasetp != NULL)
                                        (void) strcpy(datasetp, dp);
                                if (mountpointp != NULL)
                                        (void) strcpy(mountpointp, mountpoint);
                                ret = 1;
                        }
                        break;
                }

        }

        return (ret);
}

/*
 * This method builds values for "sharesmb" property from the
 * nvlist argument. The values are returned in sharesmb_val variable.
 */
static int
sa_zfs_sprintf_new_prop(nvlist_t *nvl, char *sharesmb_val)
{
        char cur_val[MAXPATHLEN];
        char *name, *val;
        nvpair_t *cur;
        int err = 0;

        cur = nvlist_next_nvpair(nvl, NULL);
        while (cur != NULL) {
                name = nvpair_name(cur);
                err = nvpair_value_string(cur, &val);
                if ((err != 0) || (name == NULL) || (val == NULL))
                        return (-1);

                (void) snprintf(cur_val, MAXPATHLEN, "%s=%s,", name, val);
                (void) strlcat(sharesmb_val, cur_val, MAXPATHLEN);

                cur = nvlist_next_nvpair(nvl, cur);
        }

        return (0);
}

/*
 * This method builds values for "sharesmb" property from values
 * already existing on the share. The properties set via sa_zfs_sprint_new_prop
 * method are passed in sharesmb_val. If a existing property is already
 * set via sa_zfs_sprint_new_prop method, then they are not appended
 * to the sharesmb_val string. The returned sharesmb_val string is a combination
 * of new and existing values for 'sharesmb' property.
 */
static int
sa_zfs_sprintf_existing_prop(zfs_handle_t *handle, char *sharesmb_val)
{
        char shareopts[ZFS_MAXPROPLEN], cur_val[MAXPATHLEN];
        char *token, *last, *value;

        if (zfs_prop_get(handle, ZFS_PROP_SHARESMB, shareopts,
            sizeof (shareopts), NULL, NULL, 0, B_FALSE) != 0)
                return (-1);

        if (strstr(shareopts, "=") == NULL)
                return (0);

        for (token = strtok_r(shareopts, ",", &last); token != NULL;
            token = strtok_r(NULL, ",", &last)) {
                value = strchr(token, '=');
                if (value == NULL)
                        return (-1);
                *value++ = '\0';

                (void) snprintf(cur_val, MAXPATHLEN, "%s=", token);
                if (strstr(sharesmb_val, cur_val) == NULL) {
                        (void) strlcat(cur_val, value, MAXPATHLEN);
                        (void) strlcat(cur_val, ",", MAXPATHLEN);
                        (void) strlcat(sharesmb_val, cur_val, MAXPATHLEN);
                }
        }

        return (0);
}

/*
 * Sets the share properties on a ZFS share. For now, this method sets only
 * the "sharesmb" property.
 *
 * This method includes building a comma seperated name-value string to be
 * set on the "sharesmb" property of a ZFS share. This name-value string is
 * build in 2 steps:
 *    - New property values given as name-value pair are set first.
 *    - Existing optionset properties, which are not part of the new properties
 *      passed in step 1, are appended to the newly set properties.
 */
int
sa_zfs_setprop(sa_handle_t handle, char *path, nvlist_t *nvl)
{
        zfs_handle_t *z_fs;
        libzfs_handle_t *z_lib;
        char sharesmb_val[MAXPATHLEN];
        char *dataset, *lastcomma;

        if (nvlist_empty(nvl))
                return (0);

        if ((handle == NULL) || (path == NULL))
                return (-1);

        if ((dataset = get_zfs_dataset(handle, path, B_FALSE)) == NULL)
                return (-1);

        if ((z_lib = libzfs_init()) == NULL) {
                free(dataset);
                return (-1);
        }

        z_fs = zfs_open(z_lib, dataset, ZFS_TYPE_DATASET);
        if (z_fs == NULL) {
                free(dataset);
                libzfs_fini(z_lib);
                return (-1);
        }

        bzero(sharesmb_val, MAXPATHLEN);
        if (sa_zfs_sprintf_new_prop(nvl, sharesmb_val) != 0) {
                free(dataset);
                zfs_close(z_fs);
                libzfs_fini(z_lib);
                return (-1);
        }

        if (sa_zfs_sprintf_existing_prop(z_fs, sharesmb_val) != 0) {
                free(dataset);
                zfs_close(z_fs);
                libzfs_fini(z_lib);
                return (-1);
        }

        lastcomma = strrchr(sharesmb_val, ',');
        if ((lastcomma != NULL) && (lastcomma[1] == '\0'))
                *lastcomma = '\0';

        (void) zfs_prop_set(z_fs, zfs_prop_to_name(ZFS_PROP_SHARESMB),
            sharesmb_val);
        free(dataset);
        zfs_close(z_fs);
        libzfs_fini(z_lib);

        return (0);
}