/*
 * 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) 2007, 2010, Oracle and/or its affiliates. All rights reserved.
 * Copyright 2020 Tintri by DDN, Inc. All rights reserved.
 * Copyright 2025 RackTop Systems, Inc.
 */

#include <sys/zfs_context.h>
#include <sys/dmu.h>
#include <sys/avl.h>
#include <sys/zap.h>
#include <sys/refcount.h>
#include <sys/nvpair.h>
#ifdef _KERNEL
#include <sys/kidmap.h>
#include <sys/sid.h>
#include <sys/zfs_vfsops.h>
#include <sys/zfs_znode.h>
#endif
#include <sys/zfs_fuid.h>

/*
 * FUID Domain table(s).
 *
 * The FUID table is stored as a packed nvlist of an array
 * of nvlists which contain an index, domain string and offset
 *
 * During file system initialization the nvlist(s) are read and
 * two AVL trees are created.  One tree is keyed by the index number
 * and the other by the domain string.  Nodes are never removed from
 * trees, but new entries may be added.  If a new entry is added then
 * the zfsvfs->z_fuid_dirty flag is set to true and the caller will then
 * be responsible for calling zfs_fuid_sync() to sync the changes to disk.
 *
 */

#define FUID_IDX        "fuid_idx"
#define FUID_DOMAIN     "fuid_domain"
#define FUID_OFFSET     "fuid_offset"
#define FUID_NVP_ARRAY  "fuid_nvlist"

typedef struct fuid_domain {
        avl_node_t      f_domnode;
        avl_node_t      f_idxnode;
        ksiddomain_t    *f_ksid;
        uint64_t        f_idx;
} fuid_domain_t;

static char *nulldomain = "";

/*
 * Compare two indexes.
 */
static int
idx_compare(const void *arg1, const void *arg2)
{
        const fuid_domain_t *node1 = (const fuid_domain_t *)arg1;
        const fuid_domain_t *node2 = (const fuid_domain_t *)arg2;

        return (TREE_CMP(node1->f_idx, node2->f_idx));
}

/*
 * Compare two domain strings.
 */
static int
domain_compare(const void *arg1, const void *arg2)
{
        const fuid_domain_t *node1 = (const fuid_domain_t *)arg1;
        const fuid_domain_t *node2 = (const fuid_domain_t *)arg2;
        int val;

        val = strcmp(node1->f_ksid->kd_name, node2->f_ksid->kd_name);

        return (TREE_ISIGN(val));
}

void
zfs_fuid_avl_tree_create(avl_tree_t *idx_tree, avl_tree_t *domain_tree)
{
        avl_create(idx_tree, idx_compare,
            sizeof (fuid_domain_t), offsetof(fuid_domain_t, f_idxnode));
        avl_create(domain_tree, domain_compare,
            sizeof (fuid_domain_t), offsetof(fuid_domain_t, f_domnode));
}

/*
 * load initial fuid domain and idx trees.  This function is used by
 * both the kernel and zdb.
 */
uint64_t
zfs_fuid_table_load(objset_t *os, uint64_t fuid_obj, avl_tree_t *idx_tree,
    avl_tree_t *domain_tree)
{
        dmu_buf_t *db;
        uint64_t fuid_size;

        ASSERT(fuid_obj != 0);
        VERIFY(0 == dmu_bonus_hold(os, fuid_obj,
            FTAG, &db));
        fuid_size = *(uint64_t *)db->db_data;
        dmu_buf_rele(db, FTAG);

        if (fuid_size)  {
                nvlist_t **fuidnvp;
                nvlist_t *nvp = NULL;
                uint_t count;
                char *packed;
                int i;

                packed = kmem_alloc(fuid_size, KM_SLEEP);
                VERIFY(dmu_read(os, fuid_obj, 0,
                    fuid_size, packed, DMU_READ_PREFETCH) == 0);
                VERIFY(nvlist_unpack(packed, fuid_size,
                    &nvp, 0) == 0);
                VERIFY(nvlist_lookup_nvlist_array(nvp, FUID_NVP_ARRAY,
                    &fuidnvp, &count) == 0);

                for (i = 0; i != count; i++) {
                        fuid_domain_t *domnode;
                        char *domain;
                        uint64_t idx;

                        VERIFY(nvlist_lookup_string(fuidnvp[i], FUID_DOMAIN,
                            &domain) == 0);
                        VERIFY(nvlist_lookup_uint64(fuidnvp[i], FUID_IDX,
                            &idx) == 0);

                        domnode = kmem_alloc(sizeof (fuid_domain_t), KM_SLEEP);

                        domnode->f_idx = idx;
                        domnode->f_ksid = ksid_lookupdomain(domain);
                        avl_add(idx_tree, domnode);
                        avl_add(domain_tree, domnode);
                }
                nvlist_free(nvp);
                kmem_free(packed, fuid_size);
        }
        return (fuid_size);
}

void
zfs_fuid_table_destroy(avl_tree_t *idx_tree, avl_tree_t *domain_tree)
{
        fuid_domain_t *domnode;
        void *cookie;

        cookie = NULL;
        while (domnode = avl_destroy_nodes(domain_tree, &cookie))
                ksiddomain_rele(domnode->f_ksid);

        avl_destroy(domain_tree);
        cookie = NULL;
        while (domnode = avl_destroy_nodes(idx_tree, &cookie))
                kmem_free(domnode, sizeof (fuid_domain_t));
        avl_destroy(idx_tree);
}

char *
zfs_fuid_idx_domain(avl_tree_t *idx_tree, uint32_t idx)
{
        fuid_domain_t searchnode, *findnode;
        avl_index_t loc;

        searchnode.f_idx = idx;

        findnode = avl_find(idx_tree, &searchnode, &loc);

        return (findnode ? findnode->f_ksid->kd_name : nulldomain);
}

#ifdef _KERNEL
/*
 * Load the fuid table(s) into memory.
 */
static void
zfs_fuid_init(zfsvfs_t *zfsvfs)
{
        rw_enter(&zfsvfs->z_fuid_lock, RW_WRITER);

        if (zfsvfs->z_fuid_loaded) {
                rw_exit(&zfsvfs->z_fuid_lock);
                return;
        }

        zfs_fuid_avl_tree_create(&zfsvfs->z_fuid_idx, &zfsvfs->z_fuid_domain);

        (void) zap_lookup(zfsvfs->z_os, MASTER_NODE_OBJ,
            ZFS_FUID_TABLES, 8, 1, &zfsvfs->z_fuid_obj);
        if (zfsvfs->z_fuid_obj != 0) {
                zfsvfs->z_fuid_size = zfs_fuid_table_load(zfsvfs->z_os,
                    zfsvfs->z_fuid_obj, &zfsvfs->z_fuid_idx,
                    &zfsvfs->z_fuid_domain);
        }

        zfsvfs->z_fuid_loaded = B_TRUE;
        rw_exit(&zfsvfs->z_fuid_lock);
}

/*
 * sync out AVL trees to persistent storage.
 */
void
zfs_fuid_sync(zfsvfs_t *zfsvfs, dmu_tx_t *tx)
{
        nvlist_t *nvp;
        nvlist_t **fuids;
        size_t nvsize = 0;
        char *packed;
        dmu_buf_t *db;
        fuid_domain_t *domnode;
        int numnodes;
        int i;

        if (!zfsvfs->z_fuid_dirty) {
                return;
        }

        rw_enter(&zfsvfs->z_fuid_lock, RW_WRITER);

        /*
         * First see if table needs to be created?
         */
        if (zfsvfs->z_fuid_obj == 0) {
                zfsvfs->z_fuid_obj = dmu_object_alloc(zfsvfs->z_os,
                    DMU_OT_FUID, 1 << 14, DMU_OT_FUID_SIZE,
                    sizeof (uint64_t), tx);
                VERIFY(zap_add(zfsvfs->z_os, MASTER_NODE_OBJ,
                    ZFS_FUID_TABLES, sizeof (uint64_t), 1,
                    &zfsvfs->z_fuid_obj, tx) == 0);
        }

        VERIFY(nvlist_alloc(&nvp, NV_UNIQUE_NAME, KM_SLEEP) == 0);

        numnodes = avl_numnodes(&zfsvfs->z_fuid_idx);
        fuids = kmem_alloc(numnodes * sizeof (void *), KM_SLEEP);
        for (i = 0, domnode = avl_first(&zfsvfs->z_fuid_domain); domnode; i++,
            domnode = AVL_NEXT(&zfsvfs->z_fuid_domain, domnode)) {
                VERIFY(nvlist_alloc(&fuids[i], NV_UNIQUE_NAME, KM_SLEEP) == 0);
                VERIFY(nvlist_add_uint64(fuids[i], FUID_IDX,
                    domnode->f_idx) == 0);
                VERIFY(nvlist_add_uint64(fuids[i], FUID_OFFSET, 0) == 0);
                VERIFY(nvlist_add_string(fuids[i], FUID_DOMAIN,
                    domnode->f_ksid->kd_name) == 0);
        }
        VERIFY(nvlist_add_nvlist_array(nvp, FUID_NVP_ARRAY,
            fuids, numnodes) == 0);
        for (i = 0; i != numnodes; i++)
                nvlist_free(fuids[i]);
        kmem_free(fuids, numnodes * sizeof (void *));
        VERIFY(nvlist_size(nvp, &nvsize, NV_ENCODE_XDR) == 0);
        packed = kmem_alloc(nvsize, KM_SLEEP);
        VERIFY(nvlist_pack(nvp, &packed, &nvsize,
            NV_ENCODE_XDR, KM_SLEEP) == 0);
        nvlist_free(nvp);
        zfsvfs->z_fuid_size = nvsize;
        dmu_write(zfsvfs->z_os, zfsvfs->z_fuid_obj, 0,
            zfsvfs->z_fuid_size, packed, tx);
        kmem_free(packed, zfsvfs->z_fuid_size);
        VERIFY(0 == dmu_bonus_hold(zfsvfs->z_os, zfsvfs->z_fuid_obj,
            FTAG, &db));
        dmu_buf_will_dirty(db, tx);
        *(uint64_t *)db->db_data = zfsvfs->z_fuid_size;
        dmu_buf_rele(db, FTAG);

        zfsvfs->z_fuid_dirty = B_FALSE;
        rw_exit(&zfsvfs->z_fuid_lock);
}

/*
 * Query domain table for a given domain.
 *
 * If domain isn't found and addok is set, it is added to AVL trees and
 * the zfsvfs->z_fuid_dirty flag will be set to TRUE.  It will then be
 * necessary for the caller or another thread to detect the dirty table
 * and sync out the changes.
 */
int
zfs_fuid_find_by_domain(zfsvfs_t *zfsvfs, const char *domain,
    char **retdomain, boolean_t addok)
{
        fuid_domain_t searchnode, *findnode;
        avl_index_t loc;
        krw_t rw = RW_READER;

        /*
         * If the dummy "nobody" domain then return an index of 0
         * to cause the created FUID to be a standard POSIX id
         * for the user nobody.
         */
        if (domain[0] == '\0') {
                if (retdomain)
                        *retdomain = nulldomain;
                return (0);
        }

        searchnode.f_ksid = ksid_lookupdomain(domain);
        if (retdomain)
                *retdomain = searchnode.f_ksid->kd_name;
        if (!zfsvfs->z_fuid_loaded)
                zfs_fuid_init(zfsvfs);

retry:
        rw_enter(&zfsvfs->z_fuid_lock, rw);
        findnode = avl_find(&zfsvfs->z_fuid_domain, &searchnode, &loc);

        if (findnode) {
                rw_exit(&zfsvfs->z_fuid_lock);
                ksiddomain_rele(searchnode.f_ksid);
                return (findnode->f_idx);
        } else if (addok) {
                fuid_domain_t *domnode;
                uint64_t retidx;

                if (rw == RW_READER && !rw_tryupgrade(&zfsvfs->z_fuid_lock)) {
                        rw_exit(&zfsvfs->z_fuid_lock);
                        rw = RW_WRITER;
                        goto retry;
                }

                domnode = kmem_alloc(sizeof (fuid_domain_t), KM_SLEEP);
                domnode->f_ksid = searchnode.f_ksid;

                retidx = domnode->f_idx = avl_numnodes(&zfsvfs->z_fuid_idx) + 1;

                avl_add(&zfsvfs->z_fuid_domain, domnode);
                avl_add(&zfsvfs->z_fuid_idx, domnode);
                zfsvfs->z_fuid_dirty = B_TRUE;
                rw_exit(&zfsvfs->z_fuid_lock);
                return (retidx);
        } else {
                rw_exit(&zfsvfs->z_fuid_lock);
                return (-1);
        }
}

/*
 * Query domain table by index, returning domain string
 *
 * Returns a pointer from an avl node of the domain string.
 *
 */
const char *
zfs_fuid_find_by_idx(zfsvfs_t *zfsvfs, uint32_t idx)
{
        char *domain;

        if (idx == 0 || !zfsvfs->z_use_fuids)
                return (NULL);

        if (!zfsvfs->z_fuid_loaded)
                zfs_fuid_init(zfsvfs);

        rw_enter(&zfsvfs->z_fuid_lock, RW_READER);

        if (zfsvfs->z_fuid_obj || zfsvfs->z_fuid_dirty)
                domain = zfs_fuid_idx_domain(&zfsvfs->z_fuid_idx, idx);
        else
                domain = nulldomain;
        rw_exit(&zfsvfs->z_fuid_lock);

        ASSERT(domain);
        return (domain);
}

void
zfs_fuid_map_ids(znode_t *zp, cred_t *cr, uid_t *uidp, uid_t *gidp)
{
        *uidp = zfs_fuid_map_id(zp->z_zfsvfs, zp->z_uid, cr, ZFS_OWNER);
        *gidp = zfs_fuid_map_id(zp->z_zfsvfs, zp->z_gid, cr, ZFS_GROUP);
}

uid_t
zfs_fuid_map_id(zfsvfs_t *zfsvfs, uint64_t fuid,
    cred_t *cr, zfs_fuid_type_t type)
{
        uint32_t index = FUID_INDEX(fuid);
        const char *domain;
        uid_t id;

        if (index == 0)
                return (fuid);

        domain = zfs_fuid_find_by_idx(zfsvfs, index);
        ASSERT(domain != NULL);

        if (type == ZFS_OWNER || type == ZFS_ACE_USER) {
                (void) kidmap_getuidbysid(crgetzone(cr), domain,
                    FUID_RID(fuid), &id);
        } else {
                (void) kidmap_getgidbysid(crgetzone(cr), domain,
                    FUID_RID(fuid), &id);
        }
        return (id);
}

/*
 * Add a FUID node to the list of fuid's being created for this
 * ACL
 *
 * If ACL has multiple domains, then keep only one copy of each unique
 * domain.
 */
void
zfs_fuid_node_add(zfs_fuid_info_t **fuidpp, const char *domain, uint32_t rid,
    uint64_t idx, uint64_t id, zfs_fuid_type_t type)
{
        zfs_fuid_t *fuid;
        zfs_fuid_domain_t *fuid_domain;
        zfs_fuid_info_t *fuidp;
        uint64_t fuididx;
        boolean_t found = B_FALSE;

        if (*fuidpp == NULL)
                *fuidpp = zfs_fuid_info_alloc();

        fuidp = *fuidpp;
        /*
         * First find fuid domain index in linked list
         *
         * If one isn't found then create an entry.
         */

        for (fuididx = 1, fuid_domain = list_head(&fuidp->z_domains);
            fuid_domain; fuid_domain = list_next(&fuidp->z_domains,
            fuid_domain), fuididx++) {
                if (idx == fuid_domain->z_domidx) {
                        found = B_TRUE;
                        break;
                }
        }

        if (!found) {
                fuid_domain = kmem_alloc(sizeof (zfs_fuid_domain_t), KM_SLEEP);
                fuid_domain->z_domain = domain;
                fuid_domain->z_domidx = idx;
                list_insert_tail(&fuidp->z_domains, fuid_domain);
                fuidp->z_domain_str_sz += strlen(domain) + 1;
                fuidp->z_domain_cnt++;
        }

        if (type == ZFS_ACE_USER || type == ZFS_ACE_GROUP) {

                /*
                 * Now allocate fuid entry and add it on the end of the list
                 */

                fuid = kmem_alloc(sizeof (zfs_fuid_t), KM_SLEEP);
                fuid->z_id = id;
                fuid->z_domidx = idx;
                fuid->z_logfuid = FUID_ENCODE(fuididx, rid);

                list_insert_tail(&fuidp->z_fuids, fuid);
                fuidp->z_fuid_cnt++;
        } else {
                if (type == ZFS_OWNER)
                        fuidp->z_fuid_owner = FUID_ENCODE(fuididx, rid);
                else
                        fuidp->z_fuid_group = FUID_ENCODE(fuididx, rid);
        }
}

/*
 * Create a file system FUID, based on information in the users cred
 *
 * If cred contains KSID_OWNER then it should be used to determine
 * the uid otherwise cred's uid will be used. By default cred's gid
 * is used unless it's an ephemeral ID in which case KSID_GROUP will
 * be used if it exists.
 */
uint64_t
zfs_fuid_create_cred(zfsvfs_t *zfsvfs, zfs_fuid_type_t type,
    cred_t *cr, zfs_fuid_info_t **fuidp)
{
        uint64_t        idx;
        ksid_t          *ksid;
        uint32_t        rid;
        char            *kdomain;
        const char      *domain;
        uid_t           id;

        VERIFY(type == ZFS_OWNER || type == ZFS_GROUP);

        ksid = crgetsid(cr, (type == ZFS_OWNER) ? KSID_OWNER : KSID_GROUP);

        if (!zfsvfs->z_use_fuids || (ksid == NULL)) {
                id = (type == ZFS_OWNER) ? crgetuid(cr) : crgetgid(cr);

                if (IS_EPHEMERAL(id))
                        return ((type == ZFS_OWNER) ? UID_NOBODY : GID_NOBODY);

                return ((uint64_t)id);
        }

        /*
         * ksid is present and FUID is supported
         */
        id = (type == ZFS_OWNER) ? ksid_getid(ksid) : crgetgid(cr);

        if (!IS_EPHEMERAL(id))
                return ((uint64_t)id);

        if (type == ZFS_GROUP)
                id = ksid_getid(ksid);

        rid = ksid_getrid(ksid);
        domain = ksid_getdomain(ksid);

        idx = zfs_fuid_find_by_domain(zfsvfs, domain, &kdomain, B_TRUE);

        zfs_fuid_node_add(fuidp, kdomain, rid, idx, id, type);

        return (FUID_ENCODE(idx, rid));
}

/*
 * Create a file system FUID for an ACL ace
 * or a chown/chgrp of the file.
 * This is similar to zfs_fuid_create_cred, except that
 * we can't find the domain + rid information in the
 * cred.  Instead we have to query Winchester for the
 * domain and rid.
 *
 * During replay operations the domain+rid information is
 * found in the zfs_fuid_info_t that the replay code has
 * attached to the zfsvfs of the file system.
 */
uint64_t
zfs_fuid_create(zfsvfs_t *zfsvfs, uint64_t id, cred_t *cr,
    zfs_fuid_type_t type, zfs_fuid_info_t **fuidpp)
{
        const char *domain;
        char *kdomain;
        uint32_t fuid_idx = FUID_INDEX(id);
        uint32_t rid;
        idmap_stat status;
        uint64_t idx = 0;
        zfs_fuid_t *zfuid = NULL;
        zfs_fuid_info_t *fuidp = NULL;

        /*
         * If POSIX ID, or entry is already a FUID then
         * just return the id
         *
         * We may also be handed an already FUID'ized id via
         * chmod.
         */

        if (!zfsvfs->z_use_fuids || !IS_EPHEMERAL(id) || fuid_idx != 0)
                return (id);

        if (zfsvfs->z_replay) {
                fuidp = zfsvfs->z_fuid_replay;

                /*
                 * If we are passed an ephemeral id, but no
                 * fuid_info was logged then return NOBODY.
                 * This is most likely a result of idmap service
                 * not being available.
                 */
                if (fuidp == NULL)
                        return (UID_NOBODY);

                VERIFY3U(type, >=, ZFS_OWNER);
                VERIFY3U(type, <=, ZFS_ACE_GROUP);

                switch (type) {
                case ZFS_ACE_USER:
                case ZFS_ACE_GROUP:
                        zfuid = list_head(&fuidp->z_fuids);
                        rid = FUID_RID(zfuid->z_logfuid);
                        idx = FUID_INDEX(zfuid->z_logfuid);
                        break;
                case ZFS_OWNER:
                        rid = FUID_RID(fuidp->z_fuid_owner);
                        idx = FUID_INDEX(fuidp->z_fuid_owner);
                        break;
                case ZFS_GROUP:
                        rid = FUID_RID(fuidp->z_fuid_group);
                        idx = FUID_INDEX(fuidp->z_fuid_group);
                        break;
                };
                domain = fuidp->z_domain_table[idx - 1];
        } else {
                if (type == ZFS_OWNER || type == ZFS_ACE_USER)
                        status = kidmap_getsidbyuid(crgetzone(cr), id,
                            &domain, &rid);
                else
                        status = kidmap_getsidbygid(crgetzone(cr), id,
                            &domain, &rid);

                if (status != 0) {
                        /*
                         * When returning nobody we will need to
                         * make a dummy fuid table entry for logging
                         * purposes.
                         */
                        rid = UID_NOBODY;
                        domain = nulldomain;
                }
        }

        idx = zfs_fuid_find_by_domain(zfsvfs, domain, &kdomain, B_TRUE);

        if (!zfsvfs->z_replay)
                zfs_fuid_node_add(fuidpp, kdomain,
                    rid, idx, id, type);
        else if (zfuid != NULL) {
                list_remove(&fuidp->z_fuids, zfuid);
                kmem_free(zfuid, sizeof (zfs_fuid_t));
        }
        return (FUID_ENCODE(idx, rid));
}

void
zfs_fuid_destroy(zfsvfs_t *zfsvfs)
{
        rw_enter(&zfsvfs->z_fuid_lock, RW_WRITER);
        if (!zfsvfs->z_fuid_loaded) {
                rw_exit(&zfsvfs->z_fuid_lock);
                return;
        }
        zfs_fuid_table_destroy(&zfsvfs->z_fuid_idx, &zfsvfs->z_fuid_domain);
        rw_exit(&zfsvfs->z_fuid_lock);
}

/*
 * Allocate zfs_fuid_info for tracking FUIDs created during
 * zfs_mknode, VOP_SETATTR() or VOP_SETSECATTR()
 */
zfs_fuid_info_t *
zfs_fuid_info_alloc(void)
{
        zfs_fuid_info_t *fuidp;

        fuidp = kmem_zalloc(sizeof (zfs_fuid_info_t), KM_SLEEP);
        list_create(&fuidp->z_domains, sizeof (zfs_fuid_domain_t),
            offsetof(zfs_fuid_domain_t, z_next));
        list_create(&fuidp->z_fuids, sizeof (zfs_fuid_t),
            offsetof(zfs_fuid_t, z_next));
        return (fuidp);
}

/*
 * Release all memory associated with zfs_fuid_info_t
 */
void
zfs_fuid_info_free(zfs_fuid_info_t *fuidp)
{
        zfs_fuid_t *zfuid;
        zfs_fuid_domain_t *zdomain;

        while ((zfuid = list_head(&fuidp->z_fuids)) != NULL) {
                list_remove(&fuidp->z_fuids, zfuid);
                kmem_free(zfuid, sizeof (zfs_fuid_t));
        }

        if (fuidp->z_domain_table != NULL)
                kmem_free(fuidp->z_domain_table,
                    (sizeof (char **)) * fuidp->z_domain_cnt);

        while ((zdomain = list_head(&fuidp->z_domains)) != NULL) {
                list_remove(&fuidp->z_domains, zdomain);
                kmem_free(zdomain, sizeof (zfs_fuid_domain_t));
        }

        kmem_free(fuidp, sizeof (zfs_fuid_info_t));
}

/*
 * Alternative to: getattr(...); va.va_uid == getcruid(cr)
 * Avoids calling idmap when the cred has a ksid.
 */
boolean_t
zfs_fuid_is_cruser(zfsvfs_t *zfsvfs, uint64_t fuid, cred_t *cr)
{
        ksid_t          *ksid;
        const char      *domain;
        uint32_t        idx = FUID_INDEX(fuid);
        uint32_t        rid = FUID_RID(fuid);
        uid_t           uid = (uid_t)-1;

        if (idx == 0) {
                /* The fuid is a plain uid.  Easy. */
                return (rid == crgetuid(cr));
        }

        /* The fuid has a domain part. */
        domain = zfs_fuid_find_by_idx(zfsvfs, idx);
        ASSERT(domain != NULL);

        /*
         * If we have a ksid, we can avoid an idmap up-call.
         */
        ksid = crgetsid(cr, KSID_USER);
        if (ksid != NULL) {
                const char *ksdom = ksid_getdomain(ksid);
                ASSERT(ksdom != NULL);
                return (rid == ksid->ks_rid &&
                    strcmp(domain, ksdom) == 0);
        }

        /*
         * No ksid, so we have to idmap.
         * The checks for -1 and 0x80000000 appear to be paranoia.
         * Those should never be set in cr_uid.
         */
        (void) kidmap_getuidbysid(crgetzone(cr), domain, rid, &uid);
        if (uid == (uid_t)-1 || uid == IDMAP_WK_CREATOR_OWNER_UID)
                return (B_FALSE);
        return (uid == crgetuid(cr));
}

/*
 * Check to see if user ID is in the list of SIDs in CR.
 */
boolean_t
zfs_user_in_cred(zfsvfs_t *zfsvfs, uint64_t id, cred_t *cr)
{
        ksid_t          *ksid = crgetsid(cr, KSID_USER);
        ksidlist_t      *ksidlist = crgetsidlist(cr);

        /* Check for match with cred->cr_uid */
        if (zfs_fuid_is_cruser(zfsvfs, id, cr))
                return (B_TRUE);

        /* Check for any match in the ksidlist */
        if (ksid && ksidlist) {
                uint32_t        idx = FUID_INDEX(id);
                uint32_t        rid = FUID_RID(id);
                const char      *domain;

                if (idx == 0) {
                        /*
                         * The ID passed in has idx zero, which means
                         * it's just a Unix UID.  That can never match
                         * anything in ksid_vec[] because those all
                         * have ksid->ks_id set to a Group ID.
                         */
                        return (B_FALSE);
                }

                domain = zfs_fuid_find_by_idx(zfsvfs, idx);
                ASSERT(domain != NULL);

                if (strcmp(domain, IDMAP_WK_CREATOR_SID_AUTHORITY) == 0)
                        return (B_FALSE);

                if (ksidlist_has_sid(ksidlist, domain, rid))
                        return (B_TRUE);
        }
        return (B_FALSE);
}

/*
 * Check to see if id is a groupmember.  If cred
 * has ksid info then sidlist is checked first
 * and if still not found then POSIX groups are checked
 *
 * Will use a straight FUID compare when possible.
 */
boolean_t
zfs_groupmember(zfsvfs_t *zfsvfs, uint64_t id, cred_t *cr)
{
        ksid_t          *ksid = crgetsid(cr, KSID_GROUP);
        ksidlist_t      *ksidlist = crgetsidlist(cr);
        uid_t           gid;
        uint32_t        idx = FUID_INDEX(id);
        uint32_t        rid = FUID_RID(id);

        if (ksid != NULL && id != IDMAP_WK_CREATOR_GROUP_GID) {
                const char      *domain = NULL;
                int ngroups;

                if (idx != 0) {
                        domain = zfs_fuid_find_by_idx(zfsvfs, idx);
                        ASSERT(domain != NULL);

                        if (strcmp(domain,
                            IDMAP_WK_CREATOR_SID_AUTHORITY) == 0)
                                return (B_FALSE);

                        if (strcmp(ksid_getdomain(ksid), domain) == 0 &&
                            rid == ksid_getrid(ksid))
                                return (B_TRUE);

                        if (ksidlist != NULL &&
                            ksidlist_has_sid(ksidlist, domain, rid))
                                return (B_TRUE);
                } else {
                        if (ksid_getid(ksid) == rid)
                                return (B_TRUE);

                        if (ksidlist != NULL &&
                            ksidlist_has_pid(ksidlist, rid))
                                return (B_TRUE);
                }

                /* If there are no useful subgroups, skip the idmap lookup */
                gid = crgetgid(cr);
                ngroups = crgetngroups(cr);
                if (ksid_getid(ksid) == gid &&
                    (ngroups == 0 ||
                    (ngroups == 1 && crgetgroups(cr)[0] == gid)))
                        return (B_FALSE);
        }

        /*
         * Not found in ksidlist, check posix groups
         */
        gid = zfs_fuid_map_id(zfsvfs, id, cr, ZFS_GROUP);
        return (groupmember(gid, cr));
}

void
zfs_fuid_txhold(zfsvfs_t *zfsvfs, dmu_tx_t *tx)
{
        if (zfsvfs->z_fuid_obj == 0) {
                dmu_tx_hold_bonus(tx, DMU_NEW_OBJECT);
                dmu_tx_hold_write(tx, DMU_NEW_OBJECT, 0,
                    FUID_SIZE_ESTIMATE(zfsvfs));
                dmu_tx_hold_zap(tx, MASTER_NODE_OBJ, FALSE, NULL);
        } else {
                dmu_tx_hold_bonus(tx, zfsvfs->z_fuid_obj);
                dmu_tx_hold_write(tx, zfsvfs->z_fuid_obj, 0,
                    FUID_SIZE_ESTIMATE(zfsvfs));
        }
}
#endif