/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
 * Copyright (c) 2012, 2017 by Delphix. All rights reserved.
 * Copyright 2015 RackTop Systems.
 * Copyright 2017 Nexenta Systems, Inc.
 */

/*
 * Pool import support functions.
 *
 * To import a pool, we rely on reading the configuration information from the
 * ZFS label of each device.  If we successfully read the label, then we
 * organize the configuration information in the following hierarchy:
 *
 *      pool guid -> toplevel vdev guid -> label txg
 *
 * Duplicate entries matching this same tuple will be discarded.  Once we have
 * examined every device, we pick the best label txg config for each toplevel
 * vdev.  We then arrange these toplevel vdevs into a complete pool config, and
 * update any paths that have changed.  Finally, we attempt to import the pool
 * using our derived config, and record the results.
 */

#include <ctype.h>
#include <devid.h>
#include <dirent.h>
#include <errno.h>
#include <libintl.h>
#include <stddef.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/vtoc.h>
#include <sys/dktp/fdisk.h>
#include <sys/efi_partition.h>
#include <thread_pool.h>

#include <sys/vdev_impl.h>
#include <libzutil.h>
#include <sys/arc_impl.h>

#include "libzfs.h"
#include "libzfs_impl.h"

/*
 * Returns true if the named pool matches the given GUID.
 */
static int
pool_active(libzfs_handle_t *hdl, const char *name, uint64_t guid,
    boolean_t *isactive)
{
        zpool_handle_t *zhp;
        uint64_t theguid;

        if (zpool_open_silent(hdl, name, &zhp) != 0)
                return (-1);

        if (zhp == NULL) {
                *isactive = B_FALSE;
                return (0);
        }

        verify(nvlist_lookup_uint64(zhp->zpool_config, ZPOOL_CONFIG_POOL_GUID,
            &theguid) == 0);

        zpool_close(zhp);

        *isactive = (theguid == guid);
        return (0);
}

static nvlist_t *
refresh_config(libzfs_handle_t *hdl, nvlist_t *config)
{
        nvlist_t *nvl;
        zfs_cmd_t zc = {"\0"};
        int err, dstbuf_size;

        if (zcmd_write_conf_nvlist(hdl, &zc, config) != 0)
                return (NULL);

        dstbuf_size = MAX(CONFIG_BUF_MINSIZE, zc.zc_nvlist_conf_size * 4);

        if (zcmd_alloc_dst_nvlist(hdl, &zc, dstbuf_size) != 0) {
                zcmd_free_nvlists(&zc);
                return (NULL);
        }

        while ((err = zfs_ioctl(hdl, ZFS_IOC_POOL_TRYIMPORT,
            &zc)) != 0 && errno == ENOMEM) {
                if (zcmd_expand_dst_nvlist(hdl, &zc) != 0) {
                        zcmd_free_nvlists(&zc);
                        return (NULL);
                }
        }

        if (err) {
                zcmd_free_nvlists(&zc);
                return (NULL);
        }

        if (zcmd_read_dst_nvlist(hdl, &zc, &nvl) != 0) {
                zcmd_free_nvlists(&zc);
                return (NULL);
        }

        zcmd_free_nvlists(&zc);
        return (nvl);
}

static nvlist_t *
refresh_config_libzfs(void *handle, nvlist_t *tryconfig)
{
        return (refresh_config((libzfs_handle_t *)handle, tryconfig));
}

static int
pool_active_libzfs(void *handle, const char *name, uint64_t guid,
    boolean_t *isactive)
{
        return (pool_active((libzfs_handle_t *)handle, name, guid, isactive));
}

const pool_config_ops_t libzfs_config_ops = {
        .pco_refresh_config = refresh_config_libzfs,
        .pco_pool_active = pool_active_libzfs,
};

/*
 * Return the offset of the given label.
 */
static uint64_t
label_offset(uint64_t size, int l)
{
        ASSERT(P2PHASE_TYPED(size, sizeof (vdev_label_t), uint64_t) == 0);
        return (l * sizeof (vdev_label_t) + (l < VDEV_LABELS / 2 ?
            0 : size - VDEV_LABELS * sizeof (vdev_label_t)));
}

/*
 * Given a file descriptor, clear (zero) the label information.
 */
int
zpool_clear_label(int fd)
{
        struct stat64 statbuf;
        int l;
        vdev_label_t *label;
        uint64_t size;
        boolean_t labels_cleared = B_FALSE, clear_l2arc_header = B_FALSE,
            header_cleared = B_FALSE;

        if (fstat64(fd, &statbuf) == -1)
                return (0);

        size = P2ALIGN_TYPED(statbuf.st_size, sizeof (vdev_label_t), uint64_t);

        if ((label = calloc(sizeof (vdev_label_t), 1)) == NULL)
                return (-1);

        for (l = 0; l < VDEV_LABELS; l++) {
                uint64_t state, guid, l2cache;
                nvlist_t *config;

                if (pread64(fd, label, sizeof (vdev_label_t),
                    label_offset(size, l)) != sizeof (vdev_label_t)) {
                        continue;
                }

                if (nvlist_unpack(label->vl_vdev_phys.vp_nvlist,
                    sizeof (label->vl_vdev_phys.vp_nvlist), &config, 0) != 0) {
                        continue;
                }

                /* Skip labels which do not have a valid guid. */
                if (nvlist_lookup_uint64(config, ZPOOL_CONFIG_GUID,
                    &guid) != 0 || guid == 0) {
                        nvlist_free(config);
                        continue;
                }

                /* Skip labels which are not in a known valid state. */
                if (nvlist_lookup_uint64(config, ZPOOL_CONFIG_POOL_STATE,
                    &state) != 0 || state > POOL_STATE_L2CACHE) {
                        nvlist_free(config);
                        continue;
                }

                /* If the device is a cache device clear the header. */
                if (!clear_l2arc_header) {
                        if (nvlist_lookup_uint64(config,
                            ZPOOL_CONFIG_POOL_STATE, &l2cache) == 0 &&
                            l2cache == POOL_STATE_L2CACHE) {
                                clear_l2arc_header = B_TRUE;
                        }
                }

                nvlist_free(config);

                /*
                 * A valid label was found, overwrite this label's nvlist
                 * and uberblocks with zeros on disk.  This is done to prevent
                 * system utilities, like blkid, from incorrectly detecting a
                 * partial label.  The leading pad space is left untouched.
                 */
                memset(label, 0, sizeof (vdev_label_t));
                size_t label_size = sizeof (vdev_label_t) - (2 * VDEV_PAD_SIZE);

                if (pwrite64(fd, label, label_size, label_offset(size, l) +
                    (2 * VDEV_PAD_SIZE)) == label_size)
                        labels_cleared = B_TRUE;
        }

        if (clear_l2arc_header) {
                _Static_assert(sizeof (*label) >= sizeof (l2arc_dev_hdr_phys_t),
                    "label < l2arc_dev_hdr_phys_t");
                memset(label, 0, sizeof (l2arc_dev_hdr_phys_t));
                if (pwrite64(fd, label, sizeof (l2arc_dev_hdr_phys_t),
                    VDEV_LABEL_START_SIZE) == sizeof (l2arc_dev_hdr_phys_t))
                        header_cleared = B_TRUE;
        }

        free(label);

        if (!labels_cleared || (clear_l2arc_header && !header_cleared))
                return (-1);

        return (0);
}

boolean_t
find_guid(nvlist_t *nv, uint64_t guid)
{
        uint64_t tmp;
        nvlist_t **child;
        uint_t c, children;

        verify(nvlist_lookup_uint64(nv, ZPOOL_CONFIG_GUID, &tmp) == 0);
        if (tmp == guid)
                return (B_TRUE);

        if (nvlist_lookup_nvlist_array(nv, ZPOOL_CONFIG_CHILDREN,
            &child, &children) == 0) {
                for (c = 0; c < children; c++)
                        if (find_guid(child[c], guid))
                                return (B_TRUE);
        }

        return (B_FALSE);
}

typedef struct aux_cbdata {
        const char      *cb_type;
        uint64_t        cb_guid;
        zpool_handle_t  *cb_zhp;
} aux_cbdata_t;

static int
find_aux(zpool_handle_t *zhp, void *data)
{
        aux_cbdata_t *cbp = data;
        nvlist_t **list;
        uint_t i, count;
        uint64_t guid;
        nvlist_t *nvroot;

        verify(nvlist_lookup_nvlist(zhp->zpool_config, ZPOOL_CONFIG_VDEV_TREE,
            &nvroot) == 0);

        if (nvlist_lookup_nvlist_array(nvroot, cbp->cb_type,
            &list, &count) == 0) {
                for (i = 0; i < count; i++) {
                        verify(nvlist_lookup_uint64(list[i],
                            ZPOOL_CONFIG_GUID, &guid) == 0);
                        if (guid == cbp->cb_guid) {
                                cbp->cb_zhp = zhp;
                                return (1);
                        }
                }
        }

        zpool_close(zhp);
        return (0);
}

/*
 * Determines if the pool is in use.  If so, it returns true and the state of
 * the pool as well as the name of the pool.  Both strings are allocated and
 * must be freed by the caller.
 */
int
zpool_in_use(libzfs_handle_t *hdl, int fd, pool_state_t *state, char **namestr,
    boolean_t *inuse)
{
        nvlist_t *config;
        char *name;
        boolean_t ret;
        uint64_t guid, vdev_guid;
        zpool_handle_t *zhp;
        nvlist_t *pool_config;
        uint64_t stateval, isspare;
        aux_cbdata_t cb = { 0 };
        boolean_t isactive;

        *inuse = B_FALSE;

        if (zpool_read_label(fd, &config, NULL) != 0 && errno == ENOMEM) {
                (void) no_memory(hdl);
                return (-1);
        }

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

        verify(nvlist_lookup_uint64(config, ZPOOL_CONFIG_POOL_STATE,
            &stateval) == 0);
        verify(nvlist_lookup_uint64(config, ZPOOL_CONFIG_GUID,
            &vdev_guid) == 0);

        if (stateval != POOL_STATE_SPARE && stateval != POOL_STATE_L2CACHE) {
                verify(nvlist_lookup_string(config, ZPOOL_CONFIG_POOL_NAME,
                    &name) == 0);
                verify(nvlist_lookup_uint64(config, ZPOOL_CONFIG_POOL_GUID,
                    &guid) == 0);
        }

        switch (stateval) {
        case POOL_STATE_EXPORTED:
                /*
                 * A pool with an exported state may in fact be imported
                 * read-only, so check the in-core state to see if it's
                 * active and imported read-only.  If it is, set
                 * its state to active.
                 */
                if (pool_active(hdl, name, guid, &isactive) == 0 && isactive &&
                    (zhp = zpool_open_canfail(hdl, name)) != NULL) {
                        if (zpool_get_prop_int(zhp, ZPOOL_PROP_READONLY, NULL))
                                stateval = POOL_STATE_ACTIVE;

                        /*
                         * All we needed the zpool handle for is the
                         * readonly prop check.
                         */
                        zpool_close(zhp);
                }

                ret = B_TRUE;
                break;

        case POOL_STATE_ACTIVE:
                /*
                 * For an active pool, we have to determine if it's really part
                 * of a currently active pool (in which case the pool will exist
                 * and the guid will be the same), or whether it's part of an
                 * active pool that was disconnected without being explicitly
                 * exported.
                 */
                if (pool_active(hdl, name, guid, &isactive) != 0) {
                        nvlist_free(config);
                        return (-1);
                }

                if (isactive) {
                        /*
                         * Because the device may have been removed while
                         * offlined, we only report it as active if the vdev is
                         * still present in the config.  Otherwise, pretend like
                         * it's not in use.
                         */
                        if ((zhp = zpool_open_canfail(hdl, name)) != NULL &&
                            (pool_config = zpool_get_config(zhp, NULL))
                            != NULL) {
                                nvlist_t *nvroot;

                                verify(nvlist_lookup_nvlist(pool_config,
                                    ZPOOL_CONFIG_VDEV_TREE, &nvroot) == 0);
                                ret = find_guid(nvroot, vdev_guid);
                        } else {
                                ret = B_FALSE;
                        }

                        /*
                         * If this is an active spare within another pool, we
                         * treat it like an unused hot spare.  This allows the
                         * user to create a pool with a hot spare that currently
                         * in use within another pool.  Since we return B_TRUE,
                         * libdiskmgt will continue to prevent generic consumers
                         * from using the device.
                         */
                        if (ret && nvlist_lookup_uint64(config,
                            ZPOOL_CONFIG_IS_SPARE, &isspare) == 0 && isspare)
                                stateval = POOL_STATE_SPARE;

                        if (zhp != NULL)
                                zpool_close(zhp);
                } else {
                        stateval = POOL_STATE_POTENTIALLY_ACTIVE;
                        ret = B_TRUE;
                }
                break;

        case POOL_STATE_SPARE:
                /*
                 * For a hot spare, it can be either definitively in use, or
                 * potentially active.  To determine if it's in use, we iterate
                 * over all pools in the system and search for one with a spare
                 * with a matching guid.
                 *
                 * Due to the shared nature of spares, we don't actually report
                 * the potentially active case as in use.  This means the user
                 * can freely create pools on the hot spares of exported pools,
                 * but to do otherwise makes the resulting code complicated, and
                 * we end up having to deal with this case anyway.
                 */
                cb.cb_zhp = NULL;
                cb.cb_guid = vdev_guid;
                cb.cb_type = ZPOOL_CONFIG_SPARES;
                if (zpool_iter(hdl, find_aux, &cb) == 1) {
                        name = (char *)zpool_get_name(cb.cb_zhp);
                        ret = B_TRUE;
                } else {
                        ret = B_FALSE;
                }
                break;

        case POOL_STATE_L2CACHE:

                /*
                 * Check if any pool is currently using this l2cache device.
                 */
                cb.cb_zhp = NULL;
                cb.cb_guid = vdev_guid;
                cb.cb_type = ZPOOL_CONFIG_L2CACHE;
                if (zpool_iter(hdl, find_aux, &cb) == 1) {
                        name = (char *)zpool_get_name(cb.cb_zhp);
                        ret = B_TRUE;
                } else {
                        ret = B_FALSE;
                }
                break;

        default:
                ret = B_FALSE;
        }


        if (ret) {
                if ((*namestr = zfs_strdup(hdl, name)) == NULL) {
                        if (cb.cb_zhp)
                                zpool_close(cb.cb_zhp);
                        nvlist_free(config);
                        return (-1);
                }
                *state = (pool_state_t)stateval;
        }

        if (cb.cb_zhp)
                zpool_close(cb.cb_zhp);

        nvlist_free(config);
        *inuse = ret;
        return (0);
}