/*
 * CDDL HEADER START
 *
 * This file and its contents are supplied under the terms of the
 * Common Development and Distribution License ("CDDL"), version 1.0.
 * You may only use this file in accordance with the terms of version
 * 1.0 of the CDDL.
 *
 * A full copy of the text of the CDDL should have accompanied this
 * source.  A copy of the CDDL is also available via the Internet at
 * http://www.illumos.org/license/CDDL.
 *
 * CDDL HEADER END
 */

/*
 * Copyright (c) 2016, 2017 by Delphix. All rights reserved.
 * Copyright 2020 Joyent, Inc.
 */

#include "lua.h"
#include "lauxlib.h"

#include <sys/zcp.h>
#include <sys/zcp_set.h>
#include <sys/zcp_change_key.h>
#include <sys/dsl_crypt.h>
#include <sys/dsl_dir.h>
#include <sys/dsl_pool.h>
#include <sys/dsl_prop.h>
#include <sys/dsl_synctask.h>
#include <sys/dsl_dataset.h>
#include <sys/dsl_bookmark.h>
#include <sys/dsl_destroy.h>
#include <sys/dmu_objset.h>
#include <sys/zfs_znode.h>
#include <sys/zfeature.h>
#include <sys/metaslab.h>

#define DST_AVG_BLKSHIFT 14

typedef struct zcp_inherit_prop_arg {
        lua_State               *zipa_state;
        const char              *zipa_prop;
        dsl_props_set_arg_t     zipa_dpsa;
} zcp_inherit_prop_arg_t;

typedef int (zcp_synctask_func_t)(lua_State *, boolean_t, nvlist_t *);
typedef struct zcp_synctask_info {
        const char *name;
        zcp_synctask_func_t *func;
        const zcp_arg_t pargs[4];
        const zcp_arg_t kwargs[2];
        zfs_space_check_t space_check;
        int blocks_modified;
} zcp_synctask_info_t;

/*
 * Generic synctask interface for channel program syncfuncs.
 *
 * To perform some action in syncing context, we'd generally call
 * dsl_sync_task(), but since the Lua script is already running inside a
 * synctask we need to leave out some actions (such as acquiring the config
 * rwlock and performing space checks).
 *
 * If 'sync' is false, executes a dry run and returns the error code.
 *
 * If we are not running in syncing context and we are not doing a dry run
 * (meaning we are running a zfs.sync function in open-context) then we
 * return a Lua error.
 *
 * This function also handles common fatal error cases for channel program
 * library functions. If a fatal error occurs, err_dsname will be the dataset
 * name reported in error messages, if supplied.
 */
static int
zcp_sync_task(lua_State *state, dsl_checkfunc_t *checkfunc,
    dsl_syncfunc_t *syncfunc, void *arg, boolean_t sync, const char *err_dsname)
{
        int err;
        zcp_run_info_t *ri = zcp_run_info(state);

        err = checkfunc(arg, ri->zri_tx);
        if (!sync)
                return (err);

        if (!ri->zri_sync) {
                return (luaL_error(state, "running functions from the zfs.sync "
                    "submodule requires passing sync=TRUE to "
                    "lzc_channel_program() (i.e. do not specify the \"-n\" "
                    "command line argument)"));
        }

        if (err == 0) {
                syncfunc(arg, ri->zri_tx);
        } else if (err == EIO) {
                if (err_dsname != NULL) {
                        return (luaL_error(state,
                            "I/O error while accessing dataset '%s'",
                            err_dsname));
                } else {
                        return (luaL_error(state,
                            "I/O error while accessing dataset."));
                }
        }

        return (err);
}


static int zcp_synctask_destroy(lua_State *, boolean_t, nvlist_t *);
static zcp_synctask_info_t zcp_synctask_destroy_info = {
        .name = "destroy",
        .func = zcp_synctask_destroy,
        .pargs = {
            {.za_name = "filesystem | snapshot", .za_lua_type = LUA_TSTRING},
            {NULL, 0}
        },
        .kwargs = {
            {.za_name = "defer", .za_lua_type = LUA_TBOOLEAN},
            {NULL, 0}
        },
        .space_check = ZFS_SPACE_CHECK_DESTROY,
        .blocks_modified = 0
};

/* ARGSUSED */
static int
zcp_synctask_destroy(lua_State *state, boolean_t sync, nvlist_t *err_details)
{
        int err;
        const char *dsname = lua_tostring(state, 1);

        boolean_t issnap = (strchr(dsname, '@') != NULL);

        if (!issnap && !lua_isnil(state, 2)) {
                return (luaL_error(state,
                    "'deferred' kwarg only supported for snapshots: %s",
                    dsname));
        }

        if (issnap) {
                dsl_destroy_snapshot_arg_t ddsa = { 0 };
                ddsa.ddsa_name = dsname;
                if (!lua_isnil(state, 2)) {
                        ddsa.ddsa_defer = lua_toboolean(state, 2);
                } else {
                        ddsa.ddsa_defer = B_FALSE;
                }

                err = zcp_sync_task(state, dsl_destroy_snapshot_check,
                    dsl_destroy_snapshot_sync, &ddsa, sync, dsname);
        } else {
                dsl_destroy_head_arg_t ddha = { 0 };
                ddha.ddha_name = dsname;

                err = zcp_sync_task(state, dsl_destroy_head_check,
                    dsl_destroy_head_sync, &ddha, sync, dsname);
        }

        return (err);
}

static int zcp_synctask_promote(lua_State *, boolean_t, nvlist_t *);
static zcp_synctask_info_t zcp_synctask_promote_info = {
        .name = "promote",
        .func = zcp_synctask_promote,
        .pargs = {
            {.za_name = "clone", .za_lua_type = LUA_TSTRING},
            {NULL, 0}
        },
        .kwargs = {
            {NULL, 0}
        },
        .space_check = ZFS_SPACE_CHECK_RESERVED,
        .blocks_modified = 3
};

static int
zcp_synctask_promote(lua_State *state, boolean_t sync, nvlist_t *err_details)
{
        int err;
        dsl_dataset_promote_arg_t ddpa = { 0 };
        const char *dsname = lua_tostring(state, 1);
        zcp_run_info_t *ri = zcp_run_info(state);

        ddpa.ddpa_clonename = dsname;
        ddpa.err_ds = err_details;
        ddpa.cr = ri->zri_cred;

        /*
         * If there was a snapshot name conflict, then err_ds will be filled
         * with a list of conflicting snapshot names.
         */
        err = zcp_sync_task(state, dsl_dataset_promote_check,
            dsl_dataset_promote_sync, &ddpa, sync, dsname);

        return (err);
}

static int zcp_synctask_rollback(lua_State *, boolean_t, nvlist_t *err_details);
static zcp_synctask_info_t zcp_synctask_rollback_info = {
        .name = "rollback",
        .func = zcp_synctask_rollback,
        .space_check = ZFS_SPACE_CHECK_RESERVED,
        .blocks_modified = 1,
        .pargs = {
            {.za_name = "filesystem", .za_lua_type = LUA_TSTRING},
            {NULL, 0}
        },
        .kwargs = {
            {NULL, 0}
        }
};

static int
zcp_synctask_rollback(lua_State *state, boolean_t sync, nvlist_t *err_details)
{
        int err;
        const char *dsname = lua_tostring(state, 1);
        dsl_dataset_rollback_arg_t ddra = { 0 };

        ddra.ddra_fsname = dsname;
        ddra.ddra_result = err_details;

        err = zcp_sync_task(state, dsl_dataset_rollback_check,
            dsl_dataset_rollback_sync, &ddra, sync, dsname);

        return (err);
}

static int zcp_synctask_snapshot(lua_State *, boolean_t, nvlist_t *);
static zcp_synctask_info_t zcp_synctask_snapshot_info = {
        .name = "snapshot",
        .func = zcp_synctask_snapshot,
        .pargs = {
            {.za_name = "filesystem@snapname | volume@snapname",
            .za_lua_type = LUA_TSTRING},
            {NULL, 0}
        },
        .kwargs = {
            {NULL, 0}
        },
        .space_check = ZFS_SPACE_CHECK_NORMAL,
        .blocks_modified = 3
};

/* ARGSUSED */
static int
zcp_synctask_snapshot(lua_State *state, boolean_t sync, nvlist_t *err_details)
{
        int err;
        dsl_dataset_snapshot_arg_t ddsa = { 0 };
        const char *dsname = lua_tostring(state, 1);
        zcp_run_info_t *ri = zcp_run_info(state);

        /*
         * On old pools, the ZIL must not be active when a snapshot is created,
         * but we can't suspend the ZIL because we're already in syncing
         * context.
         */
        if (spa_version(ri->zri_pool->dp_spa) < SPA_VERSION_FAST_SNAP) {
                return (ENOTSUP);
        }

        /*
         * We only allow for a single snapshot rather than a list, so the
         * error list output is unnecessary.
         */
        ddsa.ddsa_errors = NULL;
        ddsa.ddsa_props = NULL;
        ddsa.ddsa_cr = ri->zri_cred;
        ddsa.ddsa_snaps = fnvlist_alloc();
        fnvlist_add_boolean(ddsa.ddsa_snaps, dsname);

        zcp_cleanup_handler_t *zch = zcp_register_cleanup(state,
            (zcp_cleanup_t *)&fnvlist_free, ddsa.ddsa_snaps);

        err = zcp_sync_task(state, dsl_dataset_snapshot_check,
            dsl_dataset_snapshot_sync, &ddsa, sync, dsname);

        zcp_deregister_cleanup(state, zch);
        fnvlist_free(ddsa.ddsa_snaps);

        return (err);
}

static int zcp_synctask_inherit_prop(lua_State *, boolean_t,
    nvlist_t *err_details);
static zcp_synctask_info_t zcp_synctask_inherit_prop_info = {
        .name = "inherit",
        .func = zcp_synctask_inherit_prop,
        .space_check = ZFS_SPACE_CHECK_RESERVED,
        .blocks_modified = 2, /* 2 * numprops */
        .pargs = {
                { .za_name = "dataset", .za_lua_type = LUA_TSTRING },
                { .za_name = "property", .za_lua_type = LUA_TSTRING },
                { NULL, 0 }
        },
        .kwargs = {
                { NULL, 0 }
        },
};

static int
zcp_synctask_inherit_prop_check(void *arg, dmu_tx_t *tx)
{
        zcp_inherit_prop_arg_t *args = arg;
        zfs_prop_t prop = zfs_name_to_prop(args->zipa_prop);

        if (prop == ZPROP_INVAL) {
                if (zfs_prop_user(args->zipa_prop))
                        return (0);

                return (EINVAL);
        }

        if (zfs_prop_readonly(prop))
                return (EINVAL);

        if (!zfs_prop_inheritable(prop))
                return (EINVAL);

        return (dsl_props_set_check(&args->zipa_dpsa, tx));
}

static void
zcp_synctask_inherit_prop_sync(void *arg, dmu_tx_t *tx)
{
        zcp_inherit_prop_arg_t *args = arg;
        dsl_props_set_arg_t *dpsa = &args->zipa_dpsa;

        dsl_props_set_sync(dpsa, tx);
}

static int
zcp_synctask_inherit_prop(lua_State *state, boolean_t sync,
    nvlist_t *err_details)
{
        int err;
        zcp_inherit_prop_arg_t zipa = { 0 };
        dsl_props_set_arg_t *dpsa = &zipa.zipa_dpsa;

        const char *dsname = lua_tostring(state, 1);
        const char *prop = lua_tostring(state, 2);

        zipa.zipa_state = state;
        zipa.zipa_prop = prop;
        dpsa->dpsa_dsname = dsname;
        dpsa->dpsa_source = ZPROP_SRC_INHERITED;
        dpsa->dpsa_props = fnvlist_alloc();
        fnvlist_add_boolean(dpsa->dpsa_props, prop);

        zcp_cleanup_handler_t *zch = zcp_register_cleanup(state,
            (zcp_cleanup_t *)&fnvlist_free, dpsa->dpsa_props);

        err = zcp_sync_task(state, zcp_synctask_inherit_prop_check,
            zcp_synctask_inherit_prop_sync, &zipa, sync, dsname);

        zcp_deregister_cleanup(state, zch);
        fnvlist_free(dpsa->dpsa_props);

        return (err);
}

static int zcp_synctask_set_prop(lua_State *, boolean_t, nvlist_t *err_details);
static zcp_synctask_info_t zcp_synctask_set_prop_info = {
        .name = "set_prop",
        .func = zcp_synctask_set_prop,
        .space_check = ZFS_SPACE_CHECK_RESERVED,
        .blocks_modified = 2,
        .pargs = {
                { .za_name = "dataset", .za_lua_type = LUA_TSTRING},
                { .za_name = "property", .za_lua_type =  LUA_TSTRING},
                { .za_name = "value", .za_lua_type =  LUA_TSTRING},
                { NULL, 0 }
        },
        .kwargs = {
                { NULL, 0 }
        }
};

static int
zcp_synctask_set_prop(lua_State *state, boolean_t sync, nvlist_t *err_details)
{
        int err;
        zcp_set_prop_arg_t args = { 0 };

        const char *dsname = lua_tostring(state, 1);
        const char *prop = lua_tostring(state, 2);
        const char *val = lua_tostring(state, 3);

        args.state = state;
        args.dsname = dsname;
        args.prop = prop;
        args.val = val;

        err = zcp_sync_task(state, zcp_set_prop_check, zcp_set_prop_sync,
            &args, sync, dsname);

        return (err);
}

static int zcp_synctask_change_key(lua_State *, boolean_t, nvlist_t *);
static zcp_synctask_info_t zcp_synctask_change_key_info = {
        .name = "change_key",
        .func = zcp_synctask_change_key,
        .pargs = {
                { .za_name = "dataset", .za_lua_type = LUA_TSTRING },
                { .za_name = "key", .za_lua_type = LUA_TSTRING },
                { .za_name = "format", .za_lua_type = LUA_TSTRING },
                { NULL, 0 },
        },
        .kwargs = {
                { NULL, 0 }
        },
        .space_check = ZFS_SPACE_CHECK_RESERVED,
        /*
         * This is the same value that is used when zfs change-key is run.
         * See spa_keystore_change_key() in dsl_crypt.c
         */
        .blocks_modified = 15
};

static int
zcp_synctask_change_key(lua_State *state, boolean_t sync, nvlist_t *err_details)
{
        int err;
        spa_keystore_change_key_args_t skcka = { 0 };
        dsl_crypto_params_t *dcp = NULL;
        const char *dsname;
        const char *key;
        const char *format;
        size_t keylen;
        uint64_t keyformat;

        dsname = lua_tostring(state, 1);

        /*
         * The key may be raw key, which could contain NUL within it.
         * Use lua_tolstring() instead of lua_tostring() to obtain the length.
         */
        key = lua_tolstring(state, 2, &keylen);

        format = lua_tostring(state, 3);

        if (zfs_prop_string_to_index(ZFS_PROP_KEYFORMAT, format,
            &keyformat) != 0)
                return (SET_ERROR(EINVAL));

        err = zcp_synctask_change_key_create_params(key, keylen, keyformat,
            &dcp);
        if (err != 0)
                goto done;

        skcka.skcka_dsname = dsname;
        skcka.skcka_cp = dcp;

        zcp_cleanup_handler_t *zch = zcp_register_cleanup(state,
            (zcp_cleanup_t *)&zcp_synctask_change_key_cleanup, &skcka);

        err = zcp_sync_task(state, zcp_synctask_change_key_check,
            zcp_synctask_change_key_sync, &skcka, sync, dsname);

        zcp_deregister_cleanup(state, zch);

done:
        dsl_crypto_params_free(dcp, (err != 0 || !sync) ? B_TRUE : B_FALSE);
        return (err);
}

static int
zcp_synctask_wrapper(lua_State *state)
{
        int err;
        zcp_cleanup_handler_t *zch;
        int num_ret = 1;
        nvlist_t *err_details = fnvlist_alloc();

        /*
         * Make sure err_details is properly freed, even if a fatal error is
         * thrown during the synctask.
         */
        zch = zcp_register_cleanup(state,
            (zcp_cleanup_t *)&fnvlist_free, err_details);

        zcp_synctask_info_t *info = lua_touserdata(state, lua_upvalueindex(1));
        boolean_t sync = lua_toboolean(state, lua_upvalueindex(2));

        zcp_run_info_t *ri = zcp_run_info(state);
        dsl_pool_t *dp = ri->zri_pool;

        /* MOS space is triple-dittoed, so we multiply by 3. */
        uint64_t funcspace = (info->blocks_modified << DST_AVG_BLKSHIFT) * 3;

        zcp_parse_args(state, info->name, info->pargs, info->kwargs);

        err = 0;
        if (info->space_check != ZFS_SPACE_CHECK_NONE) {
                uint64_t quota = dsl_pool_unreserved_space(dp,
                    info->space_check);
                uint64_t used = dsl_dir_phys(dp->dp_root_dir)->dd_used_bytes +
                    ri->zri_space_used;

                if (used + funcspace > quota) {
                        err = SET_ERROR(ENOSPC);
                }
        }

        if (err == 0) {
                err = info->func(state, sync, err_details);
        }

        if (err == 0) {
                ri->zri_space_used += funcspace;
        }

        lua_pushnumber(state, (lua_Number)err);
        if (fnvlist_num_pairs(err_details) > 0) {
                (void) zcp_nvlist_to_lua(state, err_details, NULL, 0);
                num_ret++;
        }

        zcp_deregister_cleanup(state, zch);
        fnvlist_free(err_details);

        return (num_ret);
}

int
zcp_load_synctask_lib(lua_State *state, boolean_t sync)
{
        int i;
        zcp_synctask_info_t *zcp_synctask_funcs[] = {
                &zcp_synctask_destroy_info,
                &zcp_synctask_promote_info,
                &zcp_synctask_rollback_info,
                &zcp_synctask_snapshot_info,
                &zcp_synctask_inherit_prop_info,
                &zcp_synctask_set_prop_info,
                &zcp_synctask_change_key_info,
                NULL
        };

        lua_newtable(state);

        for (i = 0; zcp_synctask_funcs[i] != NULL; i++) {
                zcp_synctask_info_t *info = zcp_synctask_funcs[i];
                lua_pushlightuserdata(state, info);
                lua_pushboolean(state, sync);
                lua_pushcclosure(state, &zcp_synctask_wrapper, 2);
                lua_setfield(state, -2, info->name);
                info++;
        }

        return (1);
}