/*
 * 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) 2011, 2015 by Delphix. All rights reserved.
 * Copyright (c) 2013 Steven Hartland. All rights reserved.
 */

/*
 * zhack is a debugging tool that can write changes to ZFS pool using libzpool
 * for testing purposes. Altering pools with zhack is unsupported and may
 * result in corrupted pools.
 */

#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <sys/zfs_context.h>
#include <sys/spa.h>
#include <sys/spa_impl.h>
#include <sys/dmu.h>
#include <sys/zap.h>
#include <sys/zfs_znode.h>
#include <sys/dsl_synctask.h>
#include <sys/vdev.h>
#include <sys/fs/zfs.h>
#include <sys/dmu_objset.h>
#include <sys/dsl_pool.h>
#include <sys/zio_checksum.h>
#include <sys/zio_compress.h>
#include <sys/zfeature.h>
#include <sys/dmu_tx.h>
#undef verify
#include <libzutil.h>

extern boolean_t zfeature_checks_disable;

const char cmdname[] = "zhack";
static importargs_t g_importargs;
static char *g_pool;
static boolean_t g_readonly;

static void
usage(void)
{
        (void) fprintf(stderr,
            "Usage: %s [-c cachefile] [-d dir] <subcommand> <args> ...\n"
            "where <subcommand> <args> is one of the following:\n"
            "\n", cmdname);

        (void) fprintf(stderr,
            "    feature stat <pool>\n"
            "        print information about enabled features\n"
            "    feature enable [-d desc] <pool> <feature>\n"
            "        add a new enabled feature to the pool\n"
            "        -d <desc> sets the feature's description\n"
            "    feature ref [-md] <pool> <feature>\n"
            "        change the refcount on the given feature\n"
            "        -d decrease instead of increase the refcount\n"
            "        -m add the feature to the label if increasing refcount\n"
            "\n"
            "    <feature> : should be a feature guid\n");
        exit(1);
}


static void
fatal(spa_t *spa, void *tag, const char *fmt, ...)
{
        va_list ap;

        if (spa != NULL) {
                spa_close(spa, tag);
                (void) spa_export(g_pool, NULL, B_TRUE, B_FALSE);
        }

        va_start(ap, fmt);
        (void) fprintf(stderr, "%s: ", cmdname);
        (void) vfprintf(stderr, fmt, ap);
        va_end(ap);
        (void) fprintf(stderr, "\n");

        exit(1);
}

/* ARGSUSED */
static int
space_delta_cb(dmu_object_type_t bonustype, void *data,
    uint64_t *userp, uint64_t *groupp, uint64_t *projectp)
{
        /*
         * Is it a valid type of object to track?
         */
        if (bonustype != DMU_OT_ZNODE && bonustype != DMU_OT_SA)
                return (ENOENT);
        (void) fprintf(stderr, "modifying object that needs user accounting");
        abort();
        /* NOTREACHED */
}

/*
 * Target is the dataset whose pool we want to open.
 */
static void
zhack_import(char *target, boolean_t readonly)
{
        nvlist_t *config;
        nvlist_t *props;
        int error;

        kernel_init(readonly ? FREAD : (FREAD | FWRITE));

        dmu_objset_register_type(DMU_OST_ZFS, space_delta_cb);

        g_readonly = readonly;
        g_importargs.can_be_active = readonly;
        g_pool = strdup(target);

        error = zpool_find_config(NULL, target, &config, &g_importargs,
            &libzpool_config_ops);
        if (error)
                fatal(NULL, FTAG, "cannot import '%s'", target);

        props = NULL;
        if (readonly) {
                VERIFY(nvlist_alloc(&props, NV_UNIQUE_NAME, 0) == 0);
                VERIFY(nvlist_add_uint64(props,
                    zpool_prop_to_name(ZPOOL_PROP_READONLY), 1) == 0);
        }

        zfeature_checks_disable = B_TRUE;
        error = spa_import(target, config, props,
            (readonly ?  ZFS_IMPORT_SKIP_MMP : ZFS_IMPORT_NORMAL));
        zfeature_checks_disable = B_FALSE;
        if (error == EEXIST)
                error = 0;

        if (error)
                fatal(NULL, FTAG, "can't import '%s': %s", target,
                    strerror(error));
}

static void
zhack_spa_open(char *target, boolean_t readonly, void *tag, spa_t **spa)
{
        int err;

        zhack_import(target, readonly);

        zfeature_checks_disable = B_TRUE;
        err = spa_open(target, spa, tag);
        zfeature_checks_disable = B_FALSE;

        if (err != 0)
                fatal(*spa, FTAG, "cannot open '%s': %s", target,
                    strerror(err));
        if (spa_version(*spa) < SPA_VERSION_FEATURES) {
                fatal(*spa, FTAG, "'%s' has version %d, features not enabled",
                    target, (int)spa_version(*spa));
        }
}

static void
dump_obj(objset_t *os, uint64_t obj, const char *name)
{
        zap_cursor_t zc;
        zap_attribute_t za;

        (void) printf("%s_obj:\n", name);

        for (zap_cursor_init(&zc, os, obj);
            zap_cursor_retrieve(&zc, &za) == 0;
            zap_cursor_advance(&zc)) {
                if (za.za_integer_length == 8) {
                        ASSERT(za.za_num_integers == 1);
                        (void) printf("\t%s = %llu\n",
                            za.za_name, (u_longlong_t)za.za_first_integer);
                } else {
                        ASSERT(za.za_integer_length == 1);
                        char val[1024];
                        VERIFY(zap_lookup(os, obj, za.za_name,
                            1, sizeof (val), val) == 0);
                        (void) printf("\t%s = %s\n", za.za_name, val);
                }
        }
        zap_cursor_fini(&zc);
}

static void
dump_mos(spa_t *spa)
{
        nvlist_t *nv = spa->spa_label_features;

        (void) printf("label config:\n");
        for (nvpair_t *pair = nvlist_next_nvpair(nv, NULL);
            pair != NULL;
            pair = nvlist_next_nvpair(nv, pair)) {
                (void) printf("\t%s\n", nvpair_name(pair));
        }
}

static void
zhack_do_feature_stat(int argc, char **argv)
{
        spa_t *spa;
        objset_t *os;
        char *target;

        argc--;
        argv++;

        if (argc < 1) {
                (void) fprintf(stderr, "error: missing pool name\n");
                usage();
        }
        target = argv[0];

        zhack_spa_open(target, B_TRUE, FTAG, &spa);
        os = spa->spa_meta_objset;

        dump_obj(os, spa->spa_feat_for_read_obj, "for_read");
        dump_obj(os, spa->spa_feat_for_write_obj, "for_write");
        dump_obj(os, spa->spa_feat_desc_obj, "descriptions");
        if (spa_feature_is_active(spa, SPA_FEATURE_ENABLED_TXG)) {
                dump_obj(os, spa->spa_feat_enabled_txg_obj, "enabled_txg");
        }
        dump_mos(spa);

        spa_close(spa, FTAG);
}

static void
zhack_feature_enable_sync(void *arg, dmu_tx_t *tx)
{
        spa_t *spa = dmu_tx_pool(tx)->dp_spa;
        zfeature_info_t *feature = arg;

        feature_enable_sync(spa, feature, tx);

        spa_history_log_internal(spa, "zhack enable feature", tx,
            "guid=%s flags=%x",
            feature->fi_guid, feature->fi_flags);
}

static void
zhack_do_feature_enable(int argc, char **argv)
{
        int c;
        char *desc, *target;
        spa_t *spa;
        objset_t *mos;
        zfeature_info_t feature;
        spa_feature_t nodeps[] = { SPA_FEATURE_NONE };

        /*
         * Features are not added to the pool's label until their refcounts
         * are incremented, so fi_mos can just be left as false for now.
         */
        desc = NULL;
        feature.fi_uname = "zhack";
        feature.fi_flags = 0;
        feature.fi_depends = nodeps;
        feature.fi_feature = SPA_FEATURE_NONE;

        optind = 1;
        while ((c = getopt(argc, argv, "rmd:")) != -1) {
                switch (c) {
                case 'r':
                        feature.fi_flags |= ZFEATURE_FLAG_READONLY_COMPAT;
                        break;
                case 'd':
                        desc = strdup(optarg);
                        break;
                default:
                        usage();
                        break;
                }
        }

        if (desc == NULL)
                desc = strdup("zhack injected");
        feature.fi_desc = desc;

        argc -= optind;
        argv += optind;

        if (argc < 2) {
                (void) fprintf(stderr, "error: missing feature or pool name\n");
                usage();
        }
        target = argv[0];
        feature.fi_guid = argv[1];

        if (!zfeature_is_valid_guid(feature.fi_guid))
                fatal(NULL, FTAG, "invalid feature guid: %s", feature.fi_guid);

        zhack_spa_open(target, B_FALSE, FTAG, &spa);
        mos = spa->spa_meta_objset;

        if (zfeature_is_supported(feature.fi_guid))
                fatal(spa, FTAG, "'%s' is a real feature, will not enable");
        if (0 == zap_contains(mos, spa->spa_feat_desc_obj, feature.fi_guid))
                fatal(spa, FTAG, "feature already enabled: %s",
                    feature.fi_guid);

        VERIFY0(dsl_sync_task(spa_name(spa), NULL,
            zhack_feature_enable_sync, &feature, 5, ZFS_SPACE_CHECK_NORMAL));

        spa_close(spa, FTAG);

        free(desc);
}

static void
feature_incr_sync(void *arg, dmu_tx_t *tx)
{
        spa_t *spa = dmu_tx_pool(tx)->dp_spa;
        zfeature_info_t *feature = arg;
        uint64_t refcount;

        VERIFY0(feature_get_refcount_from_disk(spa, feature, &refcount));
        feature_sync(spa, feature, refcount + 1, tx);
        spa_history_log_internal(spa, "zhack feature incr", tx,
            "guid=%s", feature->fi_guid);
}

static void
feature_decr_sync(void *arg, dmu_tx_t *tx)
{
        spa_t *spa = dmu_tx_pool(tx)->dp_spa;
        zfeature_info_t *feature = arg;
        uint64_t refcount;

        VERIFY0(feature_get_refcount_from_disk(spa, feature, &refcount));
        feature_sync(spa, feature, refcount - 1, tx);
        spa_history_log_internal(spa, "zhack feature decr", tx,
            "guid=%s", feature->fi_guid);
}

static void
zhack_do_feature_ref(int argc, char **argv)
{
        int c;
        char *target;
        boolean_t decr = B_FALSE;
        spa_t *spa;
        objset_t *mos;
        zfeature_info_t feature;
        spa_feature_t nodeps[] = { SPA_FEATURE_NONE };

        /*
         * fi_desc does not matter here because it was written to disk
         * when the feature was enabled, but we need to properly set the
         * feature for read or write based on the information we read off
         * disk later.
         */
        feature.fi_uname = "zhack";
        feature.fi_flags = 0;
        feature.fi_desc = NULL;
        feature.fi_depends = nodeps;
        feature.fi_feature = SPA_FEATURE_NONE;

        optind = 1;
        while ((c = getopt(argc, argv, "md")) != -1) {
                switch (c) {
                case 'm':
                        feature.fi_flags |= ZFEATURE_FLAG_MOS;
                        break;
                case 'd':
                        decr = B_TRUE;
                        break;
                default:
                        usage();
                        break;
                }
        }
        argc -= optind;
        argv += optind;

        if (argc < 2) {
                (void) fprintf(stderr, "error: missing feature or pool name\n");
                usage();
        }
        target = argv[0];
        feature.fi_guid = argv[1];

        if (!zfeature_is_valid_guid(feature.fi_guid))
                fatal(NULL, FTAG, "invalid feature guid: %s", feature.fi_guid);

        zhack_spa_open(target, B_FALSE, FTAG, &spa);
        mos = spa->spa_meta_objset;

        if (zfeature_is_supported(feature.fi_guid)) {
                fatal(spa, FTAG,
                    "'%s' is a real feature, will not change refcount");
        }

        if (0 == zap_contains(mos, spa->spa_feat_for_read_obj,
            feature.fi_guid)) {
                feature.fi_flags &= ~ZFEATURE_FLAG_READONLY_COMPAT;
        } else if (0 == zap_contains(mos, spa->spa_feat_for_write_obj,
            feature.fi_guid)) {
                feature.fi_flags |= ZFEATURE_FLAG_READONLY_COMPAT;
        } else {
                fatal(spa, FTAG, "feature is not enabled: %s", feature.fi_guid);
        }

        if (decr) {
                uint64_t count;
                if (feature_get_refcount_from_disk(spa, &feature,
                    &count) == 0 && count != 0) {
                        fatal(spa, FTAG, "feature refcount already 0: %s",
                            feature.fi_guid);
                }
        }

        VERIFY0(dsl_sync_task(spa_name(spa), NULL,
            decr ? feature_decr_sync : feature_incr_sync, &feature,
            5, ZFS_SPACE_CHECK_NORMAL));

        spa_close(spa, FTAG);
}

static int
zhack_do_feature(int argc, char **argv)
{
        char *subcommand;

        argc--;
        argv++;
        if (argc == 0) {
                (void) fprintf(stderr,
                    "error: no feature operation specified\n");
                usage();
        }

        subcommand = argv[0];
        if (strcmp(subcommand, "stat") == 0) {
                zhack_do_feature_stat(argc, argv);
        } else if (strcmp(subcommand, "enable") == 0) {
                zhack_do_feature_enable(argc, argv);
        } else if (strcmp(subcommand, "ref") == 0) {
                zhack_do_feature_ref(argc, argv);
        } else {
                (void) fprintf(stderr, "error: unknown subcommand: %s\n",
                    subcommand);
                usage();
        }

        return (0);
}

#define MAX_NUM_PATHS 1024

int
main(int argc, char **argv)
{
        extern void zfs_prop_init(void);

        char *path[MAX_NUM_PATHS];
        const char *subcommand;
        int rv = 0;
        int c;

        g_importargs.path = path;

        dprintf_setup(&argc, argv);
        zfs_prop_init();

        while ((c = getopt(argc, argv, "c:d:")) != -1) {
                switch (c) {
                case 'c':
                        g_importargs.cachefile = optarg;
                        break;
                case 'd':
                        assert(g_importargs.paths < MAX_NUM_PATHS);
                        g_importargs.path[g_importargs.paths++] = optarg;
                        break;
                default:
                        usage();
                        break;
                }
        }

        argc -= optind;
        argv += optind;
        optind = 1;

        if (argc == 0) {
                (void) fprintf(stderr, "error: no command specified\n");
                usage();
        }

        subcommand = argv[0];

        if (strcmp(subcommand, "feature") == 0) {
                rv = zhack_do_feature(argc, argv);
        } else {
                (void) fprintf(stderr, "error: unknown subcommand: %s\n",
                    subcommand);
                usage();
        }

        if (!g_readonly && spa_export(g_pool, NULL, B_TRUE, B_FALSE) != 0) {
                fatal(NULL, FTAG, "pool export failed; "
                    "changes may not be committed to disk\n");
        }

        kernel_fini();

        return (rv);
}