/*

 * Copyright 2019-2021 The OpenSSL Project Authors. All Rights Reserved.

 *

 * Licensed under the Apache License 2.0 (the "License").  You may not use

 * this file except in compliance with the License.  You can obtain a copy

 * in the file LICENSE in the source distribution or at

 * https://www.openssl.org/source/license.html

 */

#include <stddef.h>

#include <openssl/core.h>

#include "internal/cryptlib.h"

#include "internal/core.h"

#include "internal/property.h"

#include "internal/provider.h"

struct construct_data_st {

    OSSL_LIB_CTX *libctx;

    OSSL_METHOD_STORE *store;

    int operation_id;

    int force_store;

    OSSL_METHOD_CONSTRUCT_METHOD *mcm;

    void *mcm_data;

};

static int is_temporary_method_store(int no_store, void *cbdata)

{

    struct construct_data_st *data = cbdata;

    return no_store && !data->force_store;

}

static int ossl_method_construct_reserve_store(int no_store, void *cbdata)

{

    struct construct_data_st *data = cbdata;

    if (is_temporary_method_store(no_store, data) && data->store == NULL) {

        /*

         * If we have been told not to store the method "permanently", we

         * ask for a temporary store, and store the method there.

         * The owner of |data->mcm| is completely responsible for managing

         * that temporary store.

         */

        if ((data->store = data->mcm->get_tmp_store(data->mcm_data)) == NULL)

            return 0;

    }

    return data->mcm->lock_store(data->store, data->mcm_data);

}

static int ossl_method_construct_unreserve_store(void *cbdata)

{

    struct construct_data_st *data = cbdata;

    return data->mcm->unlock_store(data->store, data->mcm_data);

}

static int ossl_method_construct_precondition(OSSL_PROVIDER *provider,

                                              int operation_id, int no_store,

                                              void *cbdata, int *result)

{

    if (!ossl_assert(result != NULL)) {

        ERR_raise(ERR_LIB_CRYPTO, ERR_R_PASSED_NULL_PARAMETER);

        return 0;

    }

    /* Assume that no bits are set */

    *result = 0;

    /* No flag bits for temporary stores */

    if (!is_temporary_method_store(no_store, cbdata)

        && !ossl_provider_test_operation_bit(provider, operation_id, result))

        return 0;

    /*

     * The result we get tells if methods have already been constructed.

     * However, we want to tell whether construction should happen (true)

     * or not (false), which is the opposite of what we got.

     */

    *result = !*result;

    return 1;

}

static int ossl_method_construct_postcondition(OSSL_PROVIDER *provider,

                                               int operation_id, int no_store,

                                               void *cbdata, int *result)

{

    if (!ossl_assert(result != NULL)) {

        ERR_raise(ERR_LIB_CRYPTO, ERR_R_PASSED_NULL_PARAMETER);

        return 0;

    }

    *result = 1;

    /* No flag bits for temporary stores */

    return is_temporary_method_store(no_store, cbdata)

        || ossl_provider_set_operation_bit(provider, operation_id);

}

static void ossl_method_construct_this(OSSL_PROVIDER *provider,

                                       const OSSL_ALGORITHM *algo,

                                       int no_store, void *cbdata)

{

    struct construct_data_st *data = cbdata;

    void *method = NULL;

    if ((method = data->mcm->construct(algo, provider, data->mcm_data))

        == NULL)

        return;

    /*

     * Note regarding putting the method in stores:

     *

     * we don't need to care if it actually got in or not here.

     * If it didn't get in, it will simply not be available when

     * ossl_method_construct() tries to get it from the store.

     *

     * It is *expected* that the put function increments the refcnt

     * of the passed method.

     */

    data->mcm->put(no_store ? data->store : NULL, method, provider, algo->algorithm_names,

                   algo->property_definition, data->mcm_data);

    /* refcnt-- because we're dropping the reference */

    data->mcm->destruct(method, data->mcm_data);

}

void *ossl_method_construct(OSSL_LIB_CTX *libctx, int operation_id,

                            OSSL_PROVIDER **provider_rw, int force_store,

                            OSSL_METHOD_CONSTRUCT_METHOD *mcm, void *mcm_data)

{

    void *method = NULL;

    OSSL_PROVIDER *provider = provider_rw != NULL ? *provider_rw : NULL;

    struct construct_data_st cbdata;

    /*

     * We might be tempted to try to look into the method store without

     * constructing to see if we can find our method there already.

     * Unfortunately that does not work well if the query contains

     * optional properties as newly loaded providers can match them better.

     * We trust that ossl_method_construct_precondition() and

     * ossl_method_construct_postcondition() make sure that the

     * ossl_algorithm_do_all() does very little when methods from

     * a provider have already been constructed.

     */

    cbdata.store = NULL;

    cbdata.force_store = force_store;

    cbdata.mcm = mcm;

    cbdata.mcm_data = mcm_data;

    ossl_algorithm_do_all(libctx, operation_id, provider,

                          ossl_method_construct_precondition,

                          ossl_method_construct_reserve_store,

                          ossl_method_construct_this,

                          ossl_method_construct_unreserve_store,

                          ossl_method_construct_postcondition,

                          &cbdata);

    /* If there is a temporary store, try there first */

    if (cbdata.store != NULL)

        method = mcm->get(cbdata.store, (const OSSL_PROVIDER **)provider_rw,

                          mcm_data);

    /* If no method was found yet, try the global store */

    if (method == NULL)

        method = mcm->get(NULL, (const OSSL_PROVIDER **)provider_rw, mcm_data);

    return method;

}