/*
 * 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 (c) 2011, 2015 by Delphix. All rights reserved.
 * Copyright (c) 2014 Integros [integros.com]
 * Copyright 2017 Joyent, Inc.
 */

#include <sys/spa.h>
#include <sys/spa_impl.h>
#include <sys/zap.h>
#include <sys/dsl_synctask.h>
#include <sys/dmu_tx.h>
#include <sys/dmu_objset.h>
#include <sys/dsl_dataset.h>
#include <sys/dsl_dir.h>
#include <sys/utsname.h>
#include <sys/cmn_err.h>
#include <sys/sunddi.h>
#include <sys/cred.h>
#include "zfs_comutil.h"
#ifdef _KERNEL
#include <sys/zone.h>
#endif

/*
 * Routines to manage the on-disk history log.
 *
 * The history log is stored as a dmu object containing
 * <packed record length, record nvlist> tuples.
 *
 * Where "record nvlist" is a nvlist containing uint64_ts and strings, and
 * "packed record length" is the packed length of the "record nvlist" stored
 * as a little endian uint64_t.
 *
 * The log is implemented as a ring buffer, though the original creation
 * of the pool ('zpool create') is never overwritten.
 *
 * The history log is tracked as object 'spa_t::spa_history'.  The bonus buffer
 * of 'spa_history' stores the offsets for logging/retrieving history as
 * 'spa_history_phys_t'.  'sh_pool_create_len' is the ending offset in bytes of
 * where the 'zpool create' record is stored.  This allows us to never
 * overwrite the original creation of the pool.  'sh_phys_max_off' is the
 * physical ending offset in bytes of the log.  This tells you the length of
 * the buffer. 'sh_eof' is the logical EOF (in bytes).  Whenever a record
 * is added, 'sh_eof' is incremented by the the size of the record.
 * 'sh_eof' is never decremented.  'sh_bof' is the logical BOF (in bytes).
 * This is where the consumer should start reading from after reading in
 * the 'zpool create' portion of the log.
 *
 * 'sh_records_lost' keeps track of how many records have been overwritten
 * and permanently lost.
 */

/* convert a logical offset to physical */
static uint64_t
spa_history_log_to_phys(uint64_t log_off, spa_history_phys_t *shpp)
{
        uint64_t phys_len;

        phys_len = shpp->sh_phys_max_off - shpp->sh_pool_create_len;
        return ((log_off - shpp->sh_pool_create_len) % phys_len
            + shpp->sh_pool_create_len);
}

void
spa_history_create_obj(spa_t *spa, dmu_tx_t *tx)
{
        dmu_buf_t *dbp;
        spa_history_phys_t *shpp;
        objset_t *mos = spa->spa_meta_objset;

        ASSERT(spa->spa_history == 0);
        spa->spa_history = dmu_object_alloc(mos, DMU_OT_SPA_HISTORY,
            SPA_OLD_MAXBLOCKSIZE, DMU_OT_SPA_HISTORY_OFFSETS,
            sizeof (spa_history_phys_t), tx);

        VERIFY(zap_add(mos, DMU_POOL_DIRECTORY_OBJECT,
            DMU_POOL_HISTORY, sizeof (uint64_t), 1,
            &spa->spa_history, tx) == 0);

        VERIFY(0 == dmu_bonus_hold(mos, spa->spa_history, FTAG, &dbp));
        ASSERT(dbp->db_size >= sizeof (spa_history_phys_t));

        shpp = dbp->db_data;
        dmu_buf_will_dirty(dbp, tx);

        /*
         * Figure out maximum size of history log.  We set it at
         * 0.1% of pool size, with a max of 1G and min of 128KB.
         */
        shpp->sh_phys_max_off =
            metaslab_class_get_dspace(spa_normal_class(spa)) / 1000;
        shpp->sh_phys_max_off = MIN(shpp->sh_phys_max_off, 1<<30);
        shpp->sh_phys_max_off = MAX(shpp->sh_phys_max_off, 128<<10);

        dmu_buf_rele(dbp, FTAG);
}

/*
 * Change 'sh_bof' to the beginning of the next record.
 */
static int
spa_history_advance_bof(spa_t *spa, spa_history_phys_t *shpp)
{
        objset_t *mos = spa->spa_meta_objset;
        uint64_t firstread, reclen, phys_bof;
        char buf[sizeof (reclen)];
        int err;

        phys_bof = spa_history_log_to_phys(shpp->sh_bof, shpp);
        firstread = MIN(sizeof (reclen), shpp->sh_phys_max_off - phys_bof);

        if ((err = dmu_read(mos, spa->spa_history, phys_bof, firstread,
            buf, DMU_READ_PREFETCH)) != 0)
                return (err);
        if (firstread != sizeof (reclen)) {
                if ((err = dmu_read(mos, spa->spa_history,
                    shpp->sh_pool_create_len, sizeof (reclen) - firstread,
                    buf + firstread, DMU_READ_PREFETCH)) != 0)
                        return (err);
        }

        reclen = LE_64(*((uint64_t *)buf));
        shpp->sh_bof += reclen + sizeof (reclen);
        shpp->sh_records_lost++;
        return (0);
}

static int
spa_history_write(spa_t *spa, void *buf, uint64_t len, spa_history_phys_t *shpp,
    dmu_tx_t *tx)
{
        uint64_t firstwrite, phys_eof;
        objset_t *mos = spa->spa_meta_objset;
        int err;

        ASSERT(MUTEX_HELD(&spa->spa_history_lock));

        /* see if we need to reset logical BOF */
        while (shpp->sh_phys_max_off - shpp->sh_pool_create_len -
            (shpp->sh_eof - shpp->sh_bof) <= len) {
                if ((err = spa_history_advance_bof(spa, shpp)) != 0) {
                        return (err);
                }
        }

        phys_eof = spa_history_log_to_phys(shpp->sh_eof, shpp);
        firstwrite = MIN(len, shpp->sh_phys_max_off - phys_eof);
        shpp->sh_eof += len;
        dmu_write(mos, spa->spa_history, phys_eof, firstwrite, buf, tx);

        len -= firstwrite;
        if (len > 0) {
                /* write out the rest at the beginning of physical file */
                dmu_write(mos, spa->spa_history, shpp->sh_pool_create_len,
                    len, (char *)buf + firstwrite, tx);
        }

        return (0);
}

static char *
spa_history_zone(void)
{
#ifdef _KERNEL
        if (INGLOBALZONE(curproc))
                return (NULL);
        return (curproc->p_zone->zone_name);
#else
        return (NULL);
#endif
}

/*
 * Post a history sysevent.
 *
 * The nvlist_t* passed into this function will be transformed into a new
 * nvlist where:
 *
 * 1. Nested nvlists will be flattened to a single level
 * 2. Keys will have their names normalized (to remove any problematic
 * characters, such as whitespace)
 *
 * The nvlist_t passed into this function will duplicated and should be freed
 * by caller.
 *
 */
static void
spa_history_log_notify(spa_t *spa, nvlist_t *nvl)
{
        nvlist_t *hist_nvl = fnvlist_alloc();
        uint64_t uint64;
        char *string;

        if (nvlist_lookup_string(nvl, ZPOOL_HIST_CMD, &string) == 0)
                fnvlist_add_string(hist_nvl, ZFS_EV_HIST_CMD, string);

        if (nvlist_lookup_string(nvl, ZPOOL_HIST_INT_NAME, &string) == 0)
                fnvlist_add_string(hist_nvl, ZFS_EV_HIST_INT_NAME, string);

        if (nvlist_lookup_string(nvl, ZPOOL_HIST_ZONE, &string) == 0)
                fnvlist_add_string(hist_nvl, ZFS_EV_HIST_ZONE, string);

        if (nvlist_lookup_string(nvl, ZPOOL_HIST_HOST, &string) == 0)
                fnvlist_add_string(hist_nvl, ZFS_EV_HIST_HOST, string);

        if (nvlist_lookup_string(nvl, ZPOOL_HIST_DSNAME, &string) == 0)
                fnvlist_add_string(hist_nvl, ZFS_EV_HIST_DSNAME, string);

        if (nvlist_lookup_string(nvl, ZPOOL_HIST_INT_STR, &string) == 0)
                fnvlist_add_string(hist_nvl, ZFS_EV_HIST_INT_STR, string);

        if (nvlist_lookup_string(nvl, ZPOOL_HIST_IOCTL, &string) == 0)
                fnvlist_add_string(hist_nvl, ZFS_EV_HIST_IOCTL, string);

        if (nvlist_lookup_string(nvl, ZPOOL_HIST_INT_NAME, &string) == 0)
                fnvlist_add_string(hist_nvl, ZFS_EV_HIST_INT_NAME, string);

        if (nvlist_lookup_uint64(nvl, ZPOOL_HIST_DSID, &uint64) == 0)
                fnvlist_add_uint64(hist_nvl, ZFS_EV_HIST_DSID, uint64);

        if (nvlist_lookup_uint64(nvl, ZPOOL_HIST_TXG, &uint64) == 0)
                fnvlist_add_uint64(hist_nvl, ZFS_EV_HIST_TXG, uint64);

        if (nvlist_lookup_uint64(nvl, ZPOOL_HIST_TIME, &uint64) == 0)
                fnvlist_add_uint64(hist_nvl, ZFS_EV_HIST_TIME, uint64);

        if (nvlist_lookup_uint64(nvl, ZPOOL_HIST_WHO, &uint64) == 0)
                fnvlist_add_uint64(hist_nvl, ZFS_EV_HIST_WHO, uint64);

        if (nvlist_lookup_uint64(nvl, ZPOOL_HIST_INT_EVENT, &uint64) == 0)
                fnvlist_add_uint64(hist_nvl, ZFS_EV_HIST_INT_EVENT, uint64);

        spa_event_notify(spa, NULL, hist_nvl, ESC_ZFS_HISTORY_EVENT);

        nvlist_free(hist_nvl);
}

/*
 * Write out a history event.
 */
/*ARGSUSED*/
static void
spa_history_log_sync(void *arg, dmu_tx_t *tx)
{
        nvlist_t        *nvl = arg;
        spa_t           *spa = dmu_tx_pool(tx)->dp_spa;
        objset_t        *mos = spa->spa_meta_objset;
        dmu_buf_t       *dbp;
        spa_history_phys_t *shpp;
        size_t          reclen;
        uint64_t        le_len;
        char            *record_packed = NULL;
        int             ret;

        /*
         * If we have an older pool that doesn't have a command
         * history object, create it now.
         */
        mutex_enter(&spa->spa_history_lock);
        if (!spa->spa_history)
                spa_history_create_obj(spa, tx);
        mutex_exit(&spa->spa_history_lock);

        /*
         * Get the offset of where we need to write via the bonus buffer.
         * Update the offset when the write completes.
         */
        VERIFY0(dmu_bonus_hold(mos, spa->spa_history, FTAG, &dbp));
        shpp = dbp->db_data;

        dmu_buf_will_dirty(dbp, tx);

#ifdef ZFS_DEBUG
        {
                dmu_object_info_t doi;
                dmu_object_info_from_db(dbp, &doi);
                ASSERT3U(doi.doi_bonus_type, ==, DMU_OT_SPA_HISTORY_OFFSETS);
        }
#endif

        fnvlist_add_uint64(nvl, ZPOOL_HIST_TIME, gethrestime_sec());
#ifdef _KERNEL
        fnvlist_add_string(nvl, ZPOOL_HIST_HOST, utsname.nodename);
#endif
        if (nvlist_exists(nvl, ZPOOL_HIST_CMD)) {
                zfs_dbgmsg("command: %s",
                    fnvlist_lookup_string(nvl, ZPOOL_HIST_CMD));
        } else if (nvlist_exists(nvl, ZPOOL_HIST_INT_NAME)) {
                if (nvlist_exists(nvl, ZPOOL_HIST_DSNAME)) {
                        zfs_dbgmsg("txg %lld %s %s (id %llu) %s",
                            fnvlist_lookup_uint64(nvl, ZPOOL_HIST_TXG),
                            fnvlist_lookup_string(nvl, ZPOOL_HIST_INT_NAME),
                            fnvlist_lookup_string(nvl, ZPOOL_HIST_DSNAME),
                            fnvlist_lookup_uint64(nvl, ZPOOL_HIST_DSID),
                            fnvlist_lookup_string(nvl, ZPOOL_HIST_INT_STR));
                } else {
                        zfs_dbgmsg("txg %lld %s %s",
                            fnvlist_lookup_uint64(nvl, ZPOOL_HIST_TXG),
                            fnvlist_lookup_string(nvl, ZPOOL_HIST_INT_NAME),
                            fnvlist_lookup_string(nvl, ZPOOL_HIST_INT_STR));
                }
                /*
                 * The history sysevent is posted only for internal history
                 * messages to show what has happened, not how it happened. For
                 * example, the following command:
                 *
                 * # zfs destroy -r tank/foo
                 *
                 * will result in one sysevent posted per dataset that is
                 * destroyed as a result of the command - which could be more
                 * than one event in total.  By contrast, if the sysevent was
                 * posted as a result of the ZPOOL_HIST_CMD key being present
                 * it would result in only one sysevent being posted with the
                 * full command line arguments, requiring the consumer to know
                 * how to parse and understand zfs(8) command invocations.
                 */
                spa_history_log_notify(spa, nvl);
        } else if (nvlist_exists(nvl, ZPOOL_HIST_IOCTL)) {
                zfs_dbgmsg("ioctl %s",
                    fnvlist_lookup_string(nvl, ZPOOL_HIST_IOCTL));
        }

        record_packed = fnvlist_pack(nvl, &reclen);

        mutex_enter(&spa->spa_history_lock);

        /* write out the packed length as little endian */
        le_len = LE_64((uint64_t)reclen);
        ret = spa_history_write(spa, &le_len, sizeof (le_len), shpp, tx);
        if (!ret)
                ret = spa_history_write(spa, record_packed, reclen, shpp, tx);

        /* The first command is the create, which we keep forever */
        if (ret == 0 && shpp->sh_pool_create_len == 0 &&
            nvlist_exists(nvl, ZPOOL_HIST_CMD)) {
                shpp->sh_pool_create_len = shpp->sh_bof = shpp->sh_eof;
        }

        mutex_exit(&spa->spa_history_lock);
        fnvlist_pack_free(record_packed, reclen);
        dmu_buf_rele(dbp, FTAG);
        fnvlist_free(nvl);
}

/*
 * Write out a history event.
 */
int
spa_history_log(spa_t *spa, const char *msg)
{
        int err;
        nvlist_t *nvl = fnvlist_alloc();

        fnvlist_add_string(nvl, ZPOOL_HIST_CMD, msg);
        err = spa_history_log_nvl(spa, nvl);
        fnvlist_free(nvl);
        return (err);
}

int
spa_history_log_nvl(spa_t *spa, nvlist_t *nvl)
{
        int err = 0;
        dmu_tx_t *tx;
        nvlist_t *nvarg, *in_nvl = NULL;

        if (spa_version(spa) < SPA_VERSION_ZPOOL_HISTORY || !spa_writeable(spa))
                return (SET_ERROR(EINVAL));

        err = nvlist_lookup_nvlist(nvl, ZPOOL_HIST_INPUT_NVL, &in_nvl);
        if (err == 0) {
                (void) nvlist_remove_all(in_nvl, ZPOOL_HIDDEN_ARGS);
        }

        tx = dmu_tx_create_dd(spa_get_dsl(spa)->dp_mos_dir);
        err = dmu_tx_assign(tx, TXG_WAIT);
        if (err) {
                dmu_tx_abort(tx);
                return (err);
        }

        nvarg = fnvlist_dup(nvl);
        if (spa_history_zone() != NULL) {
                fnvlist_add_string(nvarg, ZPOOL_HIST_ZONE,
                    spa_history_zone());
        }
        fnvlist_add_uint64(nvarg, ZPOOL_HIST_WHO, crgetruid(CRED()));

        /* Kick this off asynchronously; errors are ignored. */
        dsl_sync_task_nowait(spa_get_dsl(spa), spa_history_log_sync,
            nvarg, 0, ZFS_SPACE_CHECK_NONE, tx);
        dmu_tx_commit(tx);

        /* spa_history_log_sync will free nvl */
        return (err);

}

/*
 * Read out the command history.
 */
int
spa_history_get(spa_t *spa, uint64_t *offp, uint64_t *len, char *buf)
{
        objset_t *mos = spa->spa_meta_objset;
        dmu_buf_t *dbp;
        uint64_t read_len, phys_read_off, phys_eof;
        uint64_t leftover = 0;
        spa_history_phys_t *shpp;
        int err;

        /*
         * If the command history doesn't exist (older pool),
         * that's ok, just return ENOENT.
         */
        if (!spa->spa_history)
                return (SET_ERROR(ENOENT));

        /*
         * The history is logged asynchronously, so when they request
         * the first chunk of history, make sure everything has been
         * synced to disk so that we get it.
         */
        if (*offp == 0 && spa_writeable(spa))
                txg_wait_synced(spa_get_dsl(spa), 0);

        if ((err = dmu_bonus_hold(mos, spa->spa_history, FTAG, &dbp)) != 0)
                return (err);
        shpp = dbp->db_data;

#ifdef ZFS_DEBUG
        {
                dmu_object_info_t doi;
                dmu_object_info_from_db(dbp, &doi);
                ASSERT3U(doi.doi_bonus_type, ==, DMU_OT_SPA_HISTORY_OFFSETS);
        }
#endif

        mutex_enter(&spa->spa_history_lock);
        phys_eof = spa_history_log_to_phys(shpp->sh_eof, shpp);

        if (*offp < shpp->sh_pool_create_len) {
                /* read in just the zpool create history */
                phys_read_off = *offp;
                read_len = MIN(*len, shpp->sh_pool_create_len -
                    phys_read_off);
        } else {
                /*
                 * Need to reset passed in offset to BOF if the passed in
                 * offset has since been overwritten.
                 */
                *offp = MAX(*offp, shpp->sh_bof);
                phys_read_off = spa_history_log_to_phys(*offp, shpp);

                /*
                 * Read up to the minimum of what the user passed down or
                 * the EOF (physical or logical).  If we hit physical EOF,
                 * use 'leftover' to read from the physical BOF.
                 */
                if (phys_read_off <= phys_eof) {
                        read_len = MIN(*len, phys_eof - phys_read_off);
                } else {
                        read_len = MIN(*len,
                            shpp->sh_phys_max_off - phys_read_off);
                        if (phys_read_off + *len > shpp->sh_phys_max_off) {
                                leftover = MIN(*len - read_len,
                                    phys_eof - shpp->sh_pool_create_len);
                        }
                }
        }

        /* offset for consumer to use next */
        *offp += read_len + leftover;

        /* tell the consumer how much you actually read */
        *len = read_len + leftover;

        if (read_len == 0) {
                mutex_exit(&spa->spa_history_lock);
                dmu_buf_rele(dbp, FTAG);
                return (0);
        }

        err = dmu_read(mos, spa->spa_history, phys_read_off, read_len, buf,
            DMU_READ_PREFETCH);
        if (leftover && err == 0) {
                err = dmu_read(mos, spa->spa_history, shpp->sh_pool_create_len,
                    leftover, buf + read_len, DMU_READ_PREFETCH);
        }
        mutex_exit(&spa->spa_history_lock);

        dmu_buf_rele(dbp, FTAG);
        return (err);
}

/*
 * The nvlist will be consumed by this call.
 */
static void
log_internal(nvlist_t *nvl, const char *operation, spa_t *spa,
    dmu_tx_t *tx, const char *fmt, va_list adx)
{
        char *msg;

        /*
         * If this is part of creating a pool, not everything is
         * initialized yet, so don't bother logging the internal events.
         * Likewise if the pool is not writeable.
         */
        if (tx->tx_txg == TXG_INITIAL || !spa_writeable(spa)) {
                fnvlist_free(nvl);
                return;
        }

        msg = kmem_alloc(vsnprintf(NULL, 0, fmt, adx) + 1, KM_SLEEP);
        (void) vsprintf(msg, fmt, adx);
        fnvlist_add_string(nvl, ZPOOL_HIST_INT_STR, msg);
        strfree(msg);

        fnvlist_add_string(nvl, ZPOOL_HIST_INT_NAME, operation);
        fnvlist_add_uint64(nvl, ZPOOL_HIST_TXG, tx->tx_txg);

        if (dmu_tx_is_syncing(tx)) {
                spa_history_log_sync(nvl, tx);
        } else {
                dsl_sync_task_nowait(spa_get_dsl(spa),
                    spa_history_log_sync, nvl, 0, ZFS_SPACE_CHECK_NONE, tx);
        }
        /* spa_history_log_sync() will free nvl */
}

void
spa_history_log_internal(spa_t *spa, const char *operation,
    dmu_tx_t *tx, const char *fmt, ...)
{
        dmu_tx_t *htx = tx;
        va_list adx;

        /* create a tx if we didn't get one */
        if (tx == NULL) {
                htx = dmu_tx_create_dd(spa_get_dsl(spa)->dp_mos_dir);
                if (dmu_tx_assign(htx, TXG_WAIT) != 0) {
                        dmu_tx_abort(htx);
                        return;
                }
        }

        va_start(adx, fmt);
        log_internal(fnvlist_alloc(), operation, spa, htx, fmt, adx);
        va_end(adx);

        /* if we didn't get a tx from the caller, commit the one we made */
        if (tx == NULL)
                dmu_tx_commit(htx);
}

void
spa_history_log_internal_ds(dsl_dataset_t *ds, const char *operation,
    dmu_tx_t *tx, const char *fmt, ...)
{
        va_list adx;
        char namebuf[ZFS_MAX_DATASET_NAME_LEN];
        nvlist_t *nvl = fnvlist_alloc();

        ASSERT(tx != NULL);

        dsl_dataset_name(ds, namebuf);
        fnvlist_add_string(nvl, ZPOOL_HIST_DSNAME, namebuf);
        fnvlist_add_uint64(nvl, ZPOOL_HIST_DSID, ds->ds_object);

        va_start(adx, fmt);
        log_internal(nvl, operation, dsl_dataset_get_spa(ds), tx, fmt, adx);
        va_end(adx);
}

void
spa_history_log_internal_dd(dsl_dir_t *dd, const char *operation,
    dmu_tx_t *tx, const char *fmt, ...)
{
        va_list adx;
        char namebuf[ZFS_MAX_DATASET_NAME_LEN];
        nvlist_t *nvl = fnvlist_alloc();

        ASSERT(tx != NULL);

        dsl_dir_name(dd, namebuf);
        fnvlist_add_string(nvl, ZPOOL_HIST_DSNAME, namebuf);
        fnvlist_add_uint64(nvl, ZPOOL_HIST_DSID,
            dsl_dir_phys(dd)->dd_head_dataset_obj);

        va_start(adx, fmt);
        log_internal(nvl, operation, dd->dd_pool->dp_spa, tx, fmt, adx);
        va_end(adx);
}

void
spa_history_log_version(spa_t *spa, const char *operation)
{
        spa_history_log_internal(spa, operation, NULL,
            "pool version %llu; software version %llu/%llu; uts %s %s %s %s",
            (u_longlong_t)spa_version(spa), SPA_VERSION, ZPL_VERSION,
            utsname.nodename, utsname.release, utsname.version,
            utsname.machine);
}