cmd/zhack/zhack.c

	zhack.c revision 7fdd916c474ea52896c671bbe7b56ba34a1ca132
/*
 * 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) 2013 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 ZFS_MAXNAMELEN
#undef verify
#include <libzfs.h>

extern boolean_t zfeature_checks_disable;

const char cmdname[] = "zhack";
libzfs_handle_t *g_zfs;
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)
{
    /*
     * 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
import_pool(const char *target, boolean_t readonly)
{
    nvlist_t *config;
    nvlist_t *pools;
    int error;
    char *sepp;
    spa_t *spa;
    nvpair_t *elem;
    nvlist_t *props;
    const char *name;

    kernel_init(readonly ? FREAD : (FREAD | FWRITE));
    g_zfs = libzfs_init();
    ASSERT(g_zfs != NULL);

    dmu_objset_register_type(DMU_OST_ZFS, space_delta_cb);

    g_readonly = readonly;

    /*
     * If we only want readonly access, it's OK if we find
     * a potentially-active (ie, imported into the kernel) pool from the
     * default cachefile.
     */
    if (readonly && spa_open(target, &spa, FTAG) == 0) {
        spa_close(spa, FTAG);
        return;
    }

    g_importargs.unique = B_TRUE;
    g_importargs.can_be_active = readonly;
    g_pool = strdup(target);
    if ((sepp = strpbrk(g_pool, "/@")) != NULL)
        *sepp = '\0';
    g_importargs.poolname = g_pool;
    pools = zpool_search_import(g_zfs, &g_importargs);

    if (nvlist_empty(pools)) {
        if (!g_importargs.can_be_active) {
            g_importargs.can_be_active = B_TRUE;
            if (zpool_search_import(g_zfs, &g_importargs) != NULL ||
                spa_open(target, &spa, FTAG) == 0) {
                fatal(spa, FTAG, "cannot import '%s': pool is "
                    "active; run " "\"zpool export %s\" "
                    "first\n", g_pool, g_pool);
            }
        }

        fatal(NULL, FTAG, "cannot import '%s': no such pool "
            "available\n", g_pool);
    }

    elem = nvlist_next_nvpair(pools, NULL);
    name = nvpair_name(elem);
    verify(nvpair_value_nvlist(elem, &config) == 0);

    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(name, config, props, ZFS_IMPORT_NORMAL);
    zfeature_checks_disable = B_FALSE;
    if (error == EEXIST)
        error = 0;

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

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

    import_pool(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");
    dump_mos(spa);

    spa_close(spa, FTAG);
}

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

    spa_feature_enable(spa, feature, tx);
    spa_history_log_internal(spa, "zhack enable feature", tx,
        "guid=%s can_readonly=%u",
        feature->fi_guid, feature->fi_can_readonly);
}

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

    /*
     * 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_mos = B_FALSE;
    feature.fi_can_readonly = B_FALSE;
    feature.fi_depends = nodeps;

    optind = 1;
    while ((c = getopt(argc, argv, "rmd:")) != -1) {
        switch (c) {
        case 'r':
            feature.fi_can_readonly = B_TRUE;
            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 (0 == zfeature_lookup_guid(feature.fi_guid, NULL))
        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,
        feature_enable_sync, &feature, 5));

    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;

    spa_feature_incr(spa, feature, 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;

    spa_feature_decr(spa, feature, 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)
{
    char c;
    char *target;
    boolean_t decr = B_FALSE;
    spa_t *spa;
    objset_t *mos;
    zfeature_info_t feature;
    zfeature_info_t *nodeps[] = { NULL };

    /*
     * 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_mos = B_FALSE;
    feature.fi_desc = NULL;
    feature.fi_depends = nodeps;

    optind = 1;
    while ((c = getopt(argc, argv, "md")) != -1) {
        switch (c) {
        case 'm':
            feature.fi_mos = B_TRUE;
            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 (0 == zfeature_lookup_guid(feature.fi_guid, NULL))
        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_can_readonly = B_FALSE;
    } else if (0 == zap_contains(mos, spa->spa_feat_for_write_obj,
        feature.fi_guid)) {
        feature.fi_can_readonly = B_TRUE;
    } else {
        fatal(spa, FTAG, "feature is not enabled: %s", feature.fi_guid);
    }

    if (decr && !spa_feature_is_active(spa, &feature))
        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));

    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;
    char 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");
    }

    libzfs_fini(g_zfs);
    kernel_fini();

    return (rv);
}