tdb: allow reads after prepare commit

[Samba/aatanasov.git] / source3 / registry / reg_api.c

/*
 *  Unix SMB/CIFS implementation.
 *  Virtual Windows Registry Layer
 *  Copyright (C) Volker Lendecke 2006
 *  Copyright (C) Michael Adam 2007-2008
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, see <http://www.gnu.org/licenses/>.
 */

/* Attempt to wrap the existing API in a more winreg.idl-like way */

/*
 * Here is a list of winreg.idl functions and corresponding implementations
 * provided here:
 *
 * 0x00         winreg_OpenHKCR
 * 0x01         winreg_OpenHKCU
 * 0x02         winreg_OpenHKLM
 * 0x03         winreg_OpenHKPD
 * 0x04         winreg_OpenHKU
 * 0x05         winreg_CloseKey
 * 0x06         winreg_CreateKey                        reg_createkey
 * 0x07         winreg_DeleteKey                        reg_deletekey
 * 0x08         winreg_DeleteValue                      reg_deletevalue
 * 0x09         winreg_EnumKey                          reg_enumkey
 * 0x0a         winreg_EnumValue                        reg_enumvalue
 * 0x0b         winreg_FlushKey
 * 0x0c         winreg_GetKeySecurity                   reg_getkeysecurity
 * 0x0d         winreg_LoadKey
 * 0x0e         winreg_NotifyChangeKeyValue
 * 0x0f         winreg_OpenKey                          reg_openkey
 * 0x10         winreg_QueryInfoKey                     reg_queryinfokey
 * 0x11         winreg_QueryValue                       reg_queryvalue
 * 0x12         winreg_ReplaceKey
 * 0x13         winreg_RestoreKey                       reg_restorekey
 * 0x14         winreg_SaveKey                          reg_savekey
 * 0x15         winreg_SetKeySecurity                   reg_setkeysecurity
 * 0x16         winreg_SetValue                         reg_setvalue
 * 0x17         winreg_UnLoadKey
 * 0x18         winreg_InitiateSystemShutdown
 * 0x19         winreg_AbortSystemShutdown
 * 0x1a         winreg_GetVersion                       reg_getversion
 * 0x1b         winreg_OpenHKCC
 * 0x1c         winreg_OpenHKDD
 * 0x1d         winreg_QueryMultipleValues
 * 0x1e         winreg_InitiateSystemShutdownEx
 * 0x1f         winreg_SaveKeyEx
 * 0x20         winreg_OpenHKPT
 * 0x21         winreg_OpenHKPN
 * 0x22         winreg_QueryMultipleValues2
 *
 */

#include "includes.h"
#include "regfio.h"

#undef DBGC_CLASS
#define DBGC_CLASS DBGC_REGISTRY


/**********************************************************************
 * Helper functions
 **********************************************************************/

static WERROR fill_value_cache(struct registry_key *key)
{
        if (key->values != NULL) {
                if (!reg_values_need_update(key->key, key->values)) {
                        return WERR_OK;
                }
        }

        if (!(key->values = TALLOC_ZERO_P(key, struct regval_ctr))) {
                return WERR_NOMEM;
        }
        if (fetch_reg_values(key->key, key->values) == -1) {
                TALLOC_FREE(key->values);
                return WERR_BADFILE;
        }

        return WERR_OK;
}

static WERROR fill_subkey_cache(struct registry_key *key)
{
        WERROR werr;

        if (key->subkeys != NULL) {
                if (!reg_subkeys_need_update(key->key, key->subkeys)) {
                        return WERR_OK;
                }
        }

        werr = regsubkey_ctr_init(key, &(key->subkeys));
        W_ERROR_NOT_OK_RETURN(werr);

        if (fetch_reg_keys(key->key, key->subkeys) == -1) {
                TALLOC_FREE(key->subkeys);
                return WERR_NO_MORE_ITEMS;
        }

        return WERR_OK;
}

static int regkey_destructor(struct registry_key_handle *key)
{
        return regdb_close();
}

static WERROR regkey_open_onelevel(TALLOC_CTX *mem_ctx, 
                                   struct registry_key *parent,
                                   const char *name,
                                   const struct nt_user_token *token,
                                   uint32 access_desired,
                                   struct registry_key **pregkey)
{
        WERROR          result = WERR_OK;
        struct registry_key *regkey;
        struct registry_key_handle *key;
        struct regsubkey_ctr    *subkeys = NULL;

        DEBUG(7,("regkey_open_onelevel: name = [%s]\n", name));

        SMB_ASSERT(strchr(name, '\\') == NULL);

        if (!(regkey = TALLOC_ZERO_P(mem_ctx, struct registry_key)) ||
            !(regkey->token = dup_nt_token(regkey, token)) ||
            !(regkey->key = TALLOC_ZERO_P(regkey, struct registry_key_handle)))
        {
                result = WERR_NOMEM;
                goto done;
        }

        if ( !(W_ERROR_IS_OK(result = regdb_open())) ) {
                goto done;
        }

        key = regkey->key;
        talloc_set_destructor(key, regkey_destructor);
                
        /* initialization */
        
        key->type = REG_KEY_GENERIC;

        if (name[0] == '\0') {
                /*
                 * Open a copy of the parent key
                 */
                if (!parent) {
                        result = WERR_BADFILE;
                        goto done;
                }
                key->name = talloc_strdup(key, parent->key->name);
        }
        else {
                /*
                 * Normal subkey open
                 */
                key->name = talloc_asprintf(key, "%s%s%s",
                                            parent ? parent->key->name : "",
                                            parent ? "\\": "",
                                            name);
        }

        if (key->name == NULL) {
                result = WERR_NOMEM;
                goto done;
        }

        /* Tag this as a Performance Counter Key */

        if( StrnCaseCmp(key->name, KEY_HKPD, strlen(KEY_HKPD)) == 0 )
                key->type = REG_KEY_HKPD;
        
        /* Look up the table of registry I/O operations */

        if ( !(key->ops = reghook_cache_find( key->name )) ) {
                DEBUG(0,("reg_open_onelevel: Failed to assign "
                         "registry_ops to [%s]\n", key->name ));
                result = WERR_BADFILE;
                goto done;
        }

        /* check if the path really exists; failed is indicated by -1 */
        /* if the subkey count failed, bail out */

        result = regsubkey_ctr_init(key, &subkeys);
        if (!W_ERROR_IS_OK(result)) {
                goto done;
        }

        if ( fetch_reg_keys( key, subkeys ) == -1 )  {
                result = WERR_BADFILE;
                goto done;
        }

        TALLOC_FREE( subkeys );

        if ( !regkey_access_check( key, access_desired, &key->access_granted,
                                   token ) ) {
                result = WERR_ACCESS_DENIED;
                goto done;
        }

        *pregkey = regkey;
        result = WERR_OK;
        
done:
        if ( !W_ERROR_IS_OK(result) ) {
                TALLOC_FREE(regkey);
        }

        return result;
}

WERROR reg_openhive(TALLOC_CTX *mem_ctx, const char *hive,
                    uint32 desired_access,
                    const struct nt_user_token *token,
                    struct registry_key **pkey)
{
        SMB_ASSERT(hive != NULL);
        SMB_ASSERT(hive[0] != '\0');
        SMB_ASSERT(strchr(hive, '\\') == NULL);

        return regkey_open_onelevel(mem_ctx, NULL, hive, token, desired_access,
                                    pkey);
}


/**********************************************************************
 * The API functions
 **********************************************************************/

WERROR reg_openkey(TALLOC_CTX *mem_ctx, struct registry_key *parent,
                   const char *name, uint32 desired_access,
                   struct registry_key **pkey)
{
        struct registry_key *direct_parent = parent;
        WERROR err;
        char *p, *path, *to_free;
        size_t len;

        if (!(path = SMB_STRDUP(name))) {
                return WERR_NOMEM;
        }
        to_free = path;

        len = strlen(path);

        if ((len > 0) && (path[len-1] == '\\')) {
                path[len-1] = '\0';
        }

        while ((p = strchr(path, '\\')) != NULL) {
                char *name_component;
                struct registry_key *tmp;

                if (!(name_component = SMB_STRNDUP(path, (p - path)))) {
                        err = WERR_NOMEM;
                        goto error;
                }

                err = regkey_open_onelevel(mem_ctx, direct_parent,
                                           name_component, parent->token,
                                           KEY_ENUMERATE_SUB_KEYS, &tmp);
                SAFE_FREE(name_component);

                if (!W_ERROR_IS_OK(err)) {
                        goto error;
                }
                if (direct_parent != parent) {
                        TALLOC_FREE(direct_parent);
                }

                direct_parent = tmp;
                path = p+1;
        }

        err = regkey_open_onelevel(mem_ctx, direct_parent, path, parent->token,
                                   desired_access, pkey);
 error:
        if (direct_parent != parent) {
                TALLOC_FREE(direct_parent);
        }
        SAFE_FREE(to_free);
        return err;
}

WERROR reg_enumkey(TALLOC_CTX *mem_ctx, struct registry_key *key,
                   uint32 idx, char **name, NTTIME *last_write_time)
{
        WERROR err;

        if (!(key->key->access_granted & KEY_ENUMERATE_SUB_KEYS)) {
                return WERR_ACCESS_DENIED;
        }

        if (!W_ERROR_IS_OK(err = fill_subkey_cache(key))) {
                return err;
        }

        if (idx >= regsubkey_ctr_numkeys(key->subkeys)) {
                return WERR_NO_MORE_ITEMS;
        }

        if (!(*name = talloc_strdup(mem_ctx,
                        regsubkey_ctr_specific_key(key->subkeys, idx))))
        {
                return WERR_NOMEM;
        }

        if (last_write_time) {
                *last_write_time = 0;
        }

        return WERR_OK;
}

WERROR reg_enumvalue(TALLOC_CTX *mem_ctx, struct registry_key *key,
                     uint32 idx, char **pname, struct registry_value **pval)
{
        struct registry_value *val;
        WERROR err;

        if (!(key->key->access_granted & KEY_QUERY_VALUE)) {
                return WERR_ACCESS_DENIED;
        }

        if (!(W_ERROR_IS_OK(err = fill_value_cache(key)))) {
                return err;
        }

        if (idx >= key->values->num_values) {
                return WERR_NO_MORE_ITEMS;
        }

        err = registry_pull_value(mem_ctx, &val,
                                  key->values->values[idx]->type,
                                  key->values->values[idx]->data_p,
                                  key->values->values[idx]->size,
                                  key->values->values[idx]->size);
        if (!W_ERROR_IS_OK(err)) {
                return err;
        }

        if (pname
            && !(*pname = talloc_strdup(
                         mem_ctx, key->values->values[idx]->valuename))) {
                SAFE_FREE(val);
                return WERR_NOMEM;
        }

        *pval = val;
        return WERR_OK;
}

WERROR reg_queryvalue(TALLOC_CTX *mem_ctx, struct registry_key *key,
                      const char *name, struct registry_value **pval)
{
        WERROR err;
        uint32 i;

        if (!(key->key->access_granted & KEY_QUERY_VALUE)) {
                return WERR_ACCESS_DENIED;
        }

        if (!(W_ERROR_IS_OK(err = fill_value_cache(key)))) {
                return err;
        }

        for (i=0; i<key->values->num_values; i++) {
                if (strequal(key->values->values[i]->valuename, name)) {
                        return reg_enumvalue(mem_ctx, key, i, NULL, pval);
                }
        }

        return WERR_BADFILE;
}

WERROR reg_queryinfokey(struct registry_key *key, uint32_t *num_subkeys,
                        uint32_t *max_subkeylen, uint32_t *max_subkeysize, 
                        uint32_t *num_values, uint32_t *max_valnamelen, 
                        uint32_t *max_valbufsize, uint32_t *secdescsize,
                        NTTIME *last_changed_time)
{
        uint32 i, max_size;
        size_t max_len;
        TALLOC_CTX *mem_ctx;
        WERROR err;
        struct security_descriptor *secdesc;

        if (!(key->key->access_granted & KEY_QUERY_VALUE)) {
                return WERR_ACCESS_DENIED;
        }

        if (!W_ERROR_IS_OK(fill_subkey_cache(key)) ||
            !W_ERROR_IS_OK(fill_value_cache(key))) {
                return WERR_BADFILE;
        }

        max_len = 0;
        for (i=0; i< regsubkey_ctr_numkeys(key->subkeys); i++) {
                max_len = MAX(max_len,
                        strlen(regsubkey_ctr_specific_key(key->subkeys, i)));
        }

        *num_subkeys = regsubkey_ctr_numkeys(key->subkeys);
        *max_subkeylen = max_len;
        *max_subkeysize = 0;    /* Class length? */

        max_len = 0;
        max_size = 0;
        for (i=0; i<key->values->num_values; i++) {
                max_len = MAX(max_len,
                              strlen(key->values->values[i]->valuename));
                max_size = MAX(max_size, key->values->values[i]->size);
        }

        *num_values = key->values->num_values;
        *max_valnamelen = max_len;
        *max_valbufsize = max_size;

        if (!(mem_ctx = talloc_new(key))) {
                return WERR_NOMEM;
        }

        err = regkey_get_secdesc(mem_ctx, key->key, &secdesc);
        if (!W_ERROR_IS_OK(err)) {
                TALLOC_FREE(mem_ctx);
                return err;
        }

        *secdescsize = ndr_size_security_descriptor(secdesc, NULL, 0);
        TALLOC_FREE(mem_ctx);

        *last_changed_time = 0;

        return WERR_OK;
}

WERROR reg_createkey(TALLOC_CTX *ctx, struct registry_key *parent,
                     const char *subkeypath, uint32 desired_access,
                     struct registry_key **pkey,
                     enum winreg_CreateAction *paction)
{
        struct registry_key *key = parent;
        struct registry_key *create_parent;
        TALLOC_CTX *mem_ctx;
        char *path, *end;
        WERROR err;

        /*
         * We must refuse to handle subkey-paths containing
         * a '/' character because at a lower level, after
         * normalization, '/' is treated as a key separator
         * just like '\\'.
         */
        if (strchr(subkeypath, '/') != NULL) {
                return WERR_INVALID_PARAM;
        }

        if (!(mem_ctx = talloc_new(ctx))) return WERR_NOMEM;

        if (!(path = talloc_strdup(mem_ctx, subkeypath))) {
                err = WERR_NOMEM;
                goto done;
        }

        while ((end = strchr(path, '\\')) != NULL) {
                struct registry_key *tmp;
                enum winreg_CreateAction action;

                *end = '\0';

                err = reg_createkey(mem_ctx, key, path,
                                    KEY_ENUMERATE_SUB_KEYS, &tmp, &action);
                if (!W_ERROR_IS_OK(err)) {
                        goto done;
                }

                if (key != parent) {
                        TALLOC_FREE(key);
                }

                key = tmp;
                path = end+1;
        }

        /*
         * At this point, "path" contains the one-element subkey of "key". We
         * can try to open it.
         */

        err = reg_openkey(ctx, key, path, desired_access, pkey);
        if (W_ERROR_IS_OK(err)) {
                if (paction != NULL) {
                        *paction = REG_OPENED_EXISTING_KEY;
                }
                goto done;
        }

        if (!W_ERROR_EQUAL(err, WERR_BADFILE)) {
                /*
                 * Something but "notfound" has happened, so bail out
                 */
                goto done;
        }

        /*
         * We have to make a copy of the current key, as we opened it only
         * with ENUM_SUBKEY access.
         */

        err = reg_openkey(mem_ctx, key, "", KEY_CREATE_SUB_KEY,
                          &create_parent);
        if (!W_ERROR_IS_OK(err)) {
                goto done;
        }

        /*
         * Actually create the subkey
         */

        err = fill_subkey_cache(create_parent);
        if (!W_ERROR_IS_OK(err)) goto done;

        err = create_reg_subkey(key->key, path);
        W_ERROR_NOT_OK_GOTO_DONE(err);

        /*
         * Now open the newly created key
         */

        err = reg_openkey(ctx, create_parent, path, desired_access, pkey);
        if (W_ERROR_IS_OK(err) && (paction != NULL)) {
                *paction = REG_CREATED_NEW_KEY;
        }

 done:
        TALLOC_FREE(mem_ctx);
        return err;
}

WERROR reg_deletekey(struct registry_key *parent, const char *path)
{
        WERROR err;
        char *name, *end;
        struct registry_key *tmp_key, *key;
        TALLOC_CTX *mem_ctx = talloc_stackframe();

        name = talloc_strdup(mem_ctx, path);
        if (name == NULL) {
                err = WERR_NOMEM;
                goto done;
        }

        /* check if the key has subkeys */
        err = reg_openkey(mem_ctx, parent, name, REG_KEY_READ, &key);
        W_ERROR_NOT_OK_GOTO_DONE(err);

        err = fill_subkey_cache(key);
        W_ERROR_NOT_OK_GOTO_DONE(err);

        if (regsubkey_ctr_numkeys(key->subkeys) > 0) {
                err = WERR_ACCESS_DENIED;
                goto done;
        }

        /* no subkeys - proceed with delete */
        end = strrchr(name, '\\');
        if (end != NULL) {
                *end = '\0';

                err = reg_openkey(mem_ctx, parent, name,
                                  KEY_CREATE_SUB_KEY, &tmp_key);
                W_ERROR_NOT_OK_GOTO_DONE(err);

                parent = tmp_key;
                name = end+1;
        }

        if (name[0] == '\0') {
                err = WERR_INVALID_PARAM;
                goto done;
        }

        err = delete_reg_subkey(parent->key, name);

done:
        TALLOC_FREE(mem_ctx);
        return err;
}

WERROR reg_setvalue(struct registry_key *key, const char *name,
                    const struct registry_value *val)
{
        WERROR err;
        DATA_BLOB value_data;
        int res;

        if (!(key->key->access_granted & KEY_SET_VALUE)) {
                return WERR_ACCESS_DENIED;
        }

        if (!W_ERROR_IS_OK(err = fill_value_cache(key))) {
                return err;
        }

        err = registry_push_value(key, val, &value_data);
        if (!W_ERROR_IS_OK(err)) {
                return err;
        }

        res = regval_ctr_addvalue(key->values, name, val->type,
                                  (char *)value_data.data, value_data.length);
        TALLOC_FREE(value_data.data);

        if (res == 0) {
                TALLOC_FREE(key->values);
                return WERR_NOMEM;
        }

        if (!store_reg_values(key->key, key->values)) {
                TALLOC_FREE(key->values);
                return WERR_REG_IO_FAILURE;
        }

        return WERR_OK;
}

static WERROR reg_value_exists(struct registry_key *key, const char *name)
{
        int i;

        for (i=0; i<key->values->num_values; i++) {
                if (strequal(key->values->values[i]->valuename, name)) {
                        return WERR_OK;
                }
        }

        return WERR_BADFILE;
}

WERROR reg_deletevalue(struct registry_key *key, const char *name)
{
        WERROR err;

        if (!(key->key->access_granted & KEY_SET_VALUE)) {
                return WERR_ACCESS_DENIED;
        }

        if (!W_ERROR_IS_OK(err = fill_value_cache(key))) {
                return err;
        }

        err = reg_value_exists(key, name);
        if (!W_ERROR_IS_OK(err)) {
                return err;
        }

        regval_ctr_delvalue(key->values, name);

        if (!store_reg_values(key->key, key->values)) {
                TALLOC_FREE(key->values);
                return WERR_REG_IO_FAILURE;
        }

        return WERR_OK;
}

WERROR reg_getkeysecurity(TALLOC_CTX *mem_ctx, struct registry_key *key,
                          struct security_descriptor **psecdesc)
{
        return regkey_get_secdesc(mem_ctx, key->key, psecdesc);
}

WERROR reg_setkeysecurity(struct registry_key *key,
                          struct security_descriptor *psecdesc)
{
        return regkey_set_secdesc(key->key, psecdesc);
}

WERROR reg_getversion(uint32_t *version)
{
        if (version == NULL) {
                return WERR_INVALID_PARAM;
        }

        *version = 0x00000005; /* Windows 2000 registry API version */
        return WERR_OK;
}

/*******************************************************************
 Note: topkeypat is the *full* path that this *key will be
 loaded into (including the name of the key)
 ********************************************************************/

static WERROR reg_load_tree(REGF_FILE *regfile, const char *topkeypath,
                            REGF_NK_REC *key)
{
        REGF_NK_REC *subkey;
        struct registry_key_handle registry_key;
        struct regval_ctr *values;
        struct regsubkey_ctr *subkeys;
        int i;
        char *path = NULL;
        WERROR result = WERR_OK;

        /* initialize the struct registry_key_handle structure */

        registry_key.ops = reghook_cache_find(topkeypath);
        if (!registry_key.ops) {
                DEBUG(0, ("reg_load_tree: Failed to assign registry_ops "
                          "to [%s]\n", topkeypath));
                return WERR_BADFILE;
        }

        registry_key.name = talloc_strdup(regfile->mem_ctx, topkeypath);
        if (!registry_key.name) {
                DEBUG(0, ("reg_load_tree: Talloc failed for reg_key.name!\n"));
                return WERR_NOMEM;
        }

        /* now start parsing the values and subkeys */

        result = regsubkey_ctr_init(regfile->mem_ctx, &subkeys);
        W_ERROR_NOT_OK_RETURN(result);

        values = TALLOC_ZERO_P(subkeys, struct regval_ctr);
        if (values == NULL) {
                return WERR_NOMEM;
        }

        /* copy values into the struct regval_ctr */

        for (i=0; i<key->num_values; i++) {
                regval_ctr_addvalue(values, key->values[i].valuename,
                                    key->values[i].type,
                                    (char*)key->values[i].data,
                                    (key->values[i].data_size & ~VK_DATA_IN_OFFSET));
        }

        /* copy subkeys into the struct regsubkey_ctr */

        key->subkey_index = 0;
        while ((subkey = regfio_fetch_subkey( regfile, key ))) {
                result = regsubkey_ctr_addkey(subkeys, subkey->keyname);
                if (!W_ERROR_IS_OK(result)) {
                        TALLOC_FREE(subkeys);
                        return result;
                }
        }

        /* write this key and values out */

        if (!store_reg_values(&registry_key, values)
            || !store_reg_keys(&registry_key, subkeys))
        {
                DEBUG(0,("reg_load_tree: Failed to load %s!\n", topkeypath));
                result = WERR_REG_IO_FAILURE;
        }

        TALLOC_FREE(subkeys);

        if (!W_ERROR_IS_OK(result)) {
                return result;
        }

        /* now continue to load each subkey registry tree */

        key->subkey_index = 0;
        while ((subkey = regfio_fetch_subkey(regfile, key))) {
                path = talloc_asprintf(regfile->mem_ctx,
                                       "%s\\%s",
                                       topkeypath,
                                       subkey->keyname);
                if (path == NULL) {
                        return WERR_NOMEM;
                }
                result = reg_load_tree(regfile, path, subkey);
                if (!W_ERROR_IS_OK(result)) {
                        break;
                }
        }

        return result;
}

/*******************************************************************
 ********************************************************************/

static WERROR restore_registry_key(struct registry_key_handle *krecord,
                                   const char *fname)
{
        REGF_FILE *regfile;
        REGF_NK_REC *rootkey;
        WERROR result;

        /* open the registry file....fail if the file already exists */

        regfile = regfio_open(fname, (O_RDONLY), 0);
        if (regfile == NULL) {
                DEBUG(0, ("restore_registry_key: failed to open \"%s\" (%s)\n",
                          fname, strerror(errno)));
                return ntstatus_to_werror(map_nt_error_from_unix(errno));
        }

        /* get the rootkey from the regf file and then load the tree
           via recursive calls */

        if (!(rootkey = regfio_rootkey(regfile))) {
                regfio_close(regfile);
                return WERR_REG_FILE_INVALID;
        }

        result = reg_load_tree(regfile, krecord->name, rootkey);

        /* cleanup */

        regfio_close(regfile);

        return result;
}

WERROR reg_restorekey(struct registry_key *key, const char *fname)
{
        return restore_registry_key(key->key, fname);
}

/********************************************************************
********************************************************************/

static WERROR reg_write_tree(REGF_FILE *regfile, const char *keypath,
                             REGF_NK_REC *parent)
{
        REGF_NK_REC *key;
        struct regval_ctr *values;
        struct regsubkey_ctr *subkeys;
        int i, num_subkeys;
        char *key_tmp = NULL;
        char *keyname, *parentpath;
        char *subkeypath = NULL;
        char *subkeyname;
        struct registry_key_handle registry_key;
        WERROR result = WERR_OK;
        SEC_DESC *sec_desc = NULL;

        if (!regfile) {
                return WERR_GENERAL_FAILURE;
        }

        if (!keypath) {
                return WERR_OBJECT_PATH_INVALID;
        }

        /* split up the registry key path */

        key_tmp = talloc_strdup(regfile->mem_ctx, keypath);
        if (!key_tmp) {
                return WERR_NOMEM;
        }
        if (!reg_split_key(key_tmp, &parentpath, &keyname)) {
                return WERR_OBJECT_PATH_INVALID;
        }

        if (!keyname) {
                keyname = parentpath;
        }

        /* we need a registry_key_handle object here to enumerate subkeys and values */

        ZERO_STRUCT(registry_key);

        registry_key.name = talloc_strdup(regfile->mem_ctx, keypath);
        if (registry_key.name == NULL) {
                return WERR_NOMEM;
        }

        registry_key.ops = reghook_cache_find(registry_key.name);
        if (registry_key.ops == NULL) {
                return WERR_BADFILE;
        }

        /* lookup the values and subkeys */

        result = regsubkey_ctr_init(regfile->mem_ctx, &subkeys);
        W_ERROR_NOT_OK_RETURN(result);

        values = TALLOC_ZERO_P(subkeys, struct regval_ctr);
        if (values == NULL) {
                return WERR_NOMEM;
        }

        fetch_reg_keys(&registry_key, subkeys);
        fetch_reg_values(&registry_key, values);

        result = regkey_get_secdesc(regfile->mem_ctx, &registry_key, &sec_desc);
        if (!W_ERROR_IS_OK(result)) {
                goto done;
        }

        /* write out this key */

        key = regfio_write_key(regfile, keyname, values, subkeys, sec_desc,
                               parent);
        if (key == NULL) {
                result = WERR_CAN_NOT_COMPLETE;
                goto done;
        }

        /* write each one of the subkeys out */

        num_subkeys = regsubkey_ctr_numkeys(subkeys);
        for (i=0; i<num_subkeys; i++) {
                subkeyname = regsubkey_ctr_specific_key(subkeys, i);
                subkeypath = talloc_asprintf(regfile->mem_ctx, "%s\\%s",
                                             keypath, subkeyname);
                if (subkeypath == NULL) {
                        result = WERR_NOMEM;
                        goto done;
                }
                result = reg_write_tree(regfile, subkeypath, key);
                if (!W_ERROR_IS_OK(result))
                        goto done;
        }

        DEBUG(6, ("reg_write_tree: wrote key [%s]\n", keypath));

done:
        TALLOC_FREE(subkeys);
        TALLOC_FREE(registry_key.name);

        return result;
}

static WERROR backup_registry_key(struct registry_key_handle *krecord,
                                  const char *fname)
{
        REGF_FILE *regfile;
        WERROR result;

        /* open the registry file....fail if the file already exists */

        regfile = regfio_open(fname, (O_RDWR|O_CREAT|O_EXCL),
                              (S_IREAD|S_IWRITE));
        if (regfile == NULL) {
                DEBUG(0,("backup_registry_key: failed to open \"%s\" (%s)\n",
                         fname, strerror(errno) ));
                return ntstatus_to_werror(map_nt_error_from_unix(errno));
        }

        /* write the registry tree to the file  */

        result = reg_write_tree(regfile, krecord->name, NULL);

        /* cleanup */

        regfio_close(regfile);

        return result;
}

WERROR reg_savekey(struct registry_key *key, const char *fname)
{
        return backup_registry_key(key->key, fname);
}

/**********************************************************************
 * Higher level utility functions
 **********************************************************************/

WERROR reg_deleteallvalues(struct registry_key *key)
{
        WERROR err;
        int i;

        if (!(key->key->access_granted & KEY_SET_VALUE)) {
                return WERR_ACCESS_DENIED;
        }

        if (!W_ERROR_IS_OK(err = fill_value_cache(key))) {
                return err;
        }

        for (i=0; i<key->values->num_values; i++) {
                regval_ctr_delvalue(key->values, key->values->values[i]->valuename);
        }

        if (!store_reg_values(key->key, key->values)) {
                TALLOC_FREE(key->values);
                return WERR_REG_IO_FAILURE;
        }

        return WERR_OK;
}

/*
 * Utility function to open a complete registry path including the hive prefix.
 */

WERROR reg_open_path(TALLOC_CTX *mem_ctx, const char *orig_path,
                     uint32 desired_access, const struct nt_user_token *token,
                     struct registry_key **pkey)
{
        struct registry_key *hive, *key;
        char *path, *p;
        WERROR err;

        if (!(path = SMB_STRDUP(orig_path))) {
                return WERR_NOMEM;
        }

        p = strchr(path, '\\');

        if ((p == NULL) || (p[1] == '\0')) {
                /*
                 * No key behind the hive, just return the hive
                 */

                err = reg_openhive(mem_ctx, path, desired_access, token,
                                   &hive);
                if (!W_ERROR_IS_OK(err)) {
                        SAFE_FREE(path);
                        return err;
                }
                SAFE_FREE(path);
                *pkey = hive;
                return WERR_OK;
        }

        *p = '\0';

        err = reg_openhive(mem_ctx, path, KEY_ENUMERATE_SUB_KEYS, token,
                           &hive);
        if (!W_ERROR_IS_OK(err)) {
                SAFE_FREE(path);
                return err;
        }

        err = reg_openkey(mem_ctx, hive, p+1, desired_access, &key);

        TALLOC_FREE(hive);
        SAFE_FREE(path);

        if (!W_ERROR_IS_OK(err)) {
                return err;
        }

        *pkey = key;
        return WERR_OK;
}

/*
 * Utility function to delete a registry key with all its subkeys.
 * Note that reg_deletekey returns ACCESS_DENIED when called on a
 * key that has subkeys.
 */
static WERROR reg_deletekey_recursive_internal(TALLOC_CTX *ctx,
                                               struct registry_key *parent,
                                               const char *path,
                                               bool del_key)
{
        TALLOC_CTX *mem_ctx = NULL;
        WERROR werr = WERR_OK;
        struct registry_key *key;
        char *subkey_name = NULL;
        uint32 i;

        mem_ctx = talloc_new(ctx);
        if (mem_ctx == NULL) {
                werr = WERR_NOMEM;
                goto done;
        }

        /* recurse through subkeys first */
        werr = reg_openkey(mem_ctx, parent, path, REG_KEY_ALL, &key);
        if (!W_ERROR_IS_OK(werr)) {
                goto done;
        }

        werr = fill_subkey_cache(key);
        W_ERROR_NOT_OK_GOTO_DONE(werr);

        /*
         * loop from top to bottom for perfomance:
         * this way, we need to rehash the regsubkey containers less
         */
        for (i = regsubkey_ctr_numkeys(key->subkeys) ; i > 0; i--) {
                subkey_name = regsubkey_ctr_specific_key(key->subkeys, i-1);
                werr = reg_deletekey_recursive_internal(mem_ctx, key,
                                        subkey_name,
                                        true);
                W_ERROR_NOT_OK_GOTO_DONE(werr);
        }

        if (del_key) {
                /* now delete the actual key */
                werr = reg_deletekey(parent, path);
        }

done:
        TALLOC_FREE(mem_ctx);
        return werr;
}

static WERROR reg_deletekey_recursive_trans(TALLOC_CTX *ctx,
                                            struct registry_key *parent,
                                            const char *path,
                                            bool del_key)
{
        WERROR werr;

        werr = regdb_transaction_start();
        if (!W_ERROR_IS_OK(werr)) {
                DEBUG(0, ("reg_deletekey_recursive_trans: "
                          "error starting transaction: %s\n",
                          win_errstr(werr)));
                return werr;
        }

        werr = reg_deletekey_recursive_internal(ctx, parent, path, del_key);

        if (!W_ERROR_IS_OK(werr)) {
                DEBUG(1, (__location__ " failed to delete key '%s' from key "
                          "'%s': %s\n", path, parent->key->name,
                          win_errstr(werr)));
                werr = regdb_transaction_cancel();
                if (!W_ERROR_IS_OK(werr)) {
                        DEBUG(0, ("reg_deletekey_recursive_trans: "
                                  "error cancelling transaction: %s\n",
                                  win_errstr(werr)));
                }
        } else {
                werr = regdb_transaction_commit();
                if (!W_ERROR_IS_OK(werr)) {
                        DEBUG(0, ("reg_deletekey_recursive_trans: "
                                  "error committing transaction: %s\n",
                                  win_errstr(werr)));
                }
        }

        return werr;
}

WERROR reg_deletekey_recursive(TALLOC_CTX *ctx,
                               struct registry_key *parent,
                               const char *path)
{
        return reg_deletekey_recursive_trans(ctx, parent, path, true);
}

WERROR reg_deletesubkeys_recursive(TALLOC_CTX *ctx,
                                   struct registry_key *parent,
                                   const char *path)
{
        return reg_deletekey_recursive_trans(ctx, parent, path, false);
}

#if 0
/* these two functions are unused. */

/**
 * Utility function to create a registry key without opening the hive
 * before. Assumes the hive already exists.
 */

WERROR reg_create_path(TALLOC_CTX *mem_ctx, const char *orig_path,
                       uint32 desired_access,
                       const struct nt_user_token *token,
                       enum winreg_CreateAction *paction,
                       struct registry_key **pkey)
{
        struct registry_key *hive;
        char *path, *p;
        WERROR err;

        if (!(path = SMB_STRDUP(orig_path))) {
                return WERR_NOMEM;
        }

        p = strchr(path, '\\');

        if ((p == NULL) || (p[1] == '\0')) {
                /*
                 * No key behind the hive, just return the hive
                 */

                err = reg_openhive(mem_ctx, path, desired_access, token,
                                   &hive);
                if (!W_ERROR_IS_OK(err)) {
                        SAFE_FREE(path);
                        return err;
                }
                SAFE_FREE(path);
                *pkey = hive;
                *paction = REG_OPENED_EXISTING_KEY;
                return WERR_OK;
        }

        *p = '\0';

        err = reg_openhive(mem_ctx, path,
                           (strchr(p+1, '\\') != NULL) ?
                           KEY_ENUMERATE_SUB_KEYS : KEY_CREATE_SUB_KEY,
                           token, &hive);
        if (!W_ERROR_IS_OK(err)) {
                SAFE_FREE(path);
                return err;
        }

        err = reg_createkey(mem_ctx, hive, p+1, desired_access, pkey, paction);
        SAFE_FREE(path);
        TALLOC_FREE(hive);
        return err;
}

/*
 * Utility function to create a registry key without opening the hive
 * before. Will not delete a hive.
 */

WERROR reg_delete_path(const struct nt_user_token *token,
                       const char *orig_path)
{
        struct registry_key *hive;
        char *path, *p;
        WERROR err;

        if (!(path = SMB_STRDUP(orig_path))) {
                return WERR_NOMEM;
        }

        p = strchr(path, '\\');

        if ((p == NULL) || (p[1] == '\0')) {
                SAFE_FREE(path);
                return WERR_INVALID_PARAM;
        }

        *p = '\0';

        err = reg_openhive(NULL, path,
                           (strchr(p+1, '\\') != NULL) ?
                           KEY_ENUMERATE_SUB_KEYS : KEY_CREATE_SUB_KEY,
                           token, &hive);
        if (!W_ERROR_IS_OK(err)) {
                SAFE_FREE(path);
                return err;
        }

        err = reg_deletekey(hive, p+1);
        SAFE_FREE(path);
        TALLOC_FREE(hive);
        return err;
}
#endif /* #if 0 */