/* crypto/engine/eng_list.c */

/*

 * Written by Geoff Thorpe (geoff@geoffthorpe.net) for the OpenSSL project

 * 2000.

 */

/* ====================================================================

 * Copyright (c) 1999-2001 The OpenSSL Project.  All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 *

 * 1. Redistributions of source code must retain the above copyright

 *    notice, this list of conditions and the following disclaimer.

 *

 * 2. Redistributions in binary form must reproduce the above copyright

 *    notice, this list of conditions and the following disclaimer in

 *    the documentation and/or other materials provided with the

 *    distribution.

 *

 * 3. All advertising materials mentioning features or use of this

 *    software must display the following acknowledgment:

 *    "This product includes software developed by the OpenSSL Project

 *    for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"

 *

 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to

 *    endorse or promote products derived from this software without

 *    prior written permission. For written permission, please contact

 *    licensing@OpenSSL.org.

 *

 * 5. Products derived from this software may not be called "OpenSSL"

 *    nor may "OpenSSL" appear in their names without prior written

 *    permission of the OpenSSL Project.

 *

 * 6. Redistributions of any form whatsoever must retain the following

 *    acknowledgment:

 *    "This product includes software developed by the OpenSSL Project

 *    for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"

 *

 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY

 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR

 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR

 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,

 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT

 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;

 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)

 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,

 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)

 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED

 * OF THE POSSIBILITY OF SUCH DAMAGE.

 * ====================================================================

 *

 * This product includes cryptographic software written by Eric Young

 * (eay@cryptsoft.com).  This product includes software written by Tim

 * Hudson (tjh@cryptsoft.com).

 *

 */

/* ====================================================================

 * Copyright 2002 Sun Microsystems, Inc. ALL RIGHTS RESERVED.

 * ECDH support in OpenSSL originally developed by

 * SUN MICROSYSTEMS, INC., and contributed to the OpenSSL project.

 */

#include "eng_int.h"

/*

 * The linked-list of pointers to engine types. engine_list_head incorporates

 * an implicit structural reference but engine_list_tail does not - the

 * latter is a computational niceity and only points to something that is

 * already pointed to by its predecessor in the list (or engine_list_head

 * itself). In the same way, the use of the "prev" pointer in each ENGINE is

 * to save excessive list iteration, it doesn't correspond to an extra

 * structural reference. Hence, engine_list_head, and each non-null "next"

 * pointer account for the list itself assuming exactly 1 structural

 * reference on each list member.

 */

static ENGINE *engine_list_head = NULL;

static ENGINE *engine_list_tail = NULL;

/*

 * This cleanup function is only needed internally. If it should be called,

 * we register it with the "ENGINE_cleanup()" stack to be called during

 * cleanup.

 */

static void engine_list_cleanup(void)

{

    ENGINE *iterator = engine_list_head;

    while (iterator != NULL) {

        ENGINE_remove(iterator);

        iterator = engine_list_head;

    }

    return;

}

/*

 * These static functions starting with a lower case "engine_" always take

 * place when CRYPTO_LOCK_ENGINE has been locked up.

 */

static int engine_list_add(ENGINE *e)

{

    int conflict = 0;

    ENGINE *iterator = NULL;

    if (e == NULL) {

        ENGINEerr(ENGINE_F_ENGINE_LIST_ADD, ERR_R_PASSED_NULL_PARAMETER);

        return 0;

    }

    iterator = engine_list_head;

    while (iterator && !conflict) {

        conflict = (strcmp(iterator->id, e->id) == 0);

        iterator = iterator->next;

    }

    if (conflict) {

        ENGINEerr(ENGINE_F_ENGINE_LIST_ADD, ENGINE_R_CONFLICTING_ENGINE_ID);

        return 0;

    }

    if (engine_list_head == NULL) {

        /* We are adding to an empty list. */

        if (engine_list_tail) {

            ENGINEerr(ENGINE_F_ENGINE_LIST_ADD, ENGINE_R_INTERNAL_LIST_ERROR);

            return 0;

        }

        engine_list_head = e;

        e->prev = NULL;

        /*

         * The first time the list allocates, we should register the cleanup.

         */

        engine_cleanup_add_last(engine_list_cleanup);

    } else {

        /* We are adding to the tail of an existing list. */

        if ((engine_list_tail == NULL) || (engine_list_tail->next != NULL)) {

            ENGINEerr(ENGINE_F_ENGINE_LIST_ADD, ENGINE_R_INTERNAL_LIST_ERROR);

            return 0;

        }

        engine_list_tail->next = e;

        e->prev = engine_list_tail;

    }

    /*

     * Having the engine in the list assumes a structural reference.

     */

    e->struct_ref++;

    engine_ref_debug(e, 0, 1)

        /* However it came to be, e is the last item in the list. */

        engine_list_tail = e;

    e->next = NULL;

    return 1;

}

static int engine_list_remove(ENGINE *e)

{

    ENGINE *iterator;

    if (e == NULL) {

        ENGINEerr(ENGINE_F_ENGINE_LIST_REMOVE, ERR_R_PASSED_NULL_PARAMETER);

        return 0;

    }

    /* We need to check that e is in our linked list! */

    iterator = engine_list_head;

    while (iterator && (iterator != e))

        iterator = iterator->next;

    if (iterator == NULL) {

        ENGINEerr(ENGINE_F_ENGINE_LIST_REMOVE,

                  ENGINE_R_ENGINE_IS_NOT_IN_LIST);

        return 0;

    }

    /* un-link e from the chain. */

    if (e->next)

        e->next->prev = e->prev;

    if (e->prev)

        e->prev->next = e->next;

    /* Correct our head/tail if necessary. */

    if (engine_list_head == e)

        engine_list_head = e->next;

    if (engine_list_tail == e)

        engine_list_tail = e->prev;

    engine_free_util(e, 0);

    return 1;

}

/* Get the first/last "ENGINE" type available. */

ENGINE *ENGINE_get_first(void)

{

    ENGINE *ret;

    CRYPTO_w_lock(CRYPTO_LOCK_ENGINE);

    ret = engine_list_head;

    if (ret) {

        ret->struct_ref++;

        engine_ref_debug(ret, 0, 1)

    }

    CRYPTO_w_unlock(CRYPTO_LOCK_ENGINE);

    return ret;

}

ENGINE *ENGINE_get_last(void)

{

    ENGINE *ret;

    CRYPTO_w_lock(CRYPTO_LOCK_ENGINE);

    ret = engine_list_tail;

    if (ret) {

        ret->struct_ref++;

        engine_ref_debug(ret, 0, 1)

    }

    CRYPTO_w_unlock(CRYPTO_LOCK_ENGINE);

    return ret;

}

/* Iterate to the next/previous "ENGINE" type (NULL = end of the list). */

ENGINE *ENGINE_get_next(ENGINE *e)

{

    ENGINE *ret = NULL;

    if (e == NULL) {

        ENGINEerr(ENGINE_F_ENGINE_GET_NEXT, ERR_R_PASSED_NULL_PARAMETER);

        return 0;

    }

    CRYPTO_w_lock(CRYPTO_LOCK_ENGINE);

    ret = e->next;

    if (ret) {

        /* Return a valid structural refernce to the next ENGINE */

        ret->struct_ref++;

        engine_ref_debug(ret, 0, 1)

    }

    CRYPTO_w_unlock(CRYPTO_LOCK_ENGINE);

    /* Release the structural reference to the previous ENGINE */

    ENGINE_free(e);

    return ret;

}

ENGINE *ENGINE_get_prev(ENGINE *e)

{

    ENGINE *ret = NULL;

    if (e == NULL) {

        ENGINEerr(ENGINE_F_ENGINE_GET_PREV, ERR_R_PASSED_NULL_PARAMETER);

        return 0;

    }

    CRYPTO_w_lock(CRYPTO_LOCK_ENGINE);

    ret = e->prev;

    if (ret) {

        /* Return a valid structural reference to the next ENGINE */

        ret->struct_ref++;

        engine_ref_debug(ret, 0, 1)

    }

    CRYPTO_w_unlock(CRYPTO_LOCK_ENGINE);

    /* Release the structural reference to the previous ENGINE */

    ENGINE_free(e);

    return ret;

}

/* Add another "ENGINE" type into the list. */

int ENGINE_add(ENGINE *e)

{

    int to_return = 1;

    if (e == NULL) {

        ENGINEerr(ENGINE_F_ENGINE_ADD, ERR_R_PASSED_NULL_PARAMETER);

        return 0;

    }

    if ((e->id == NULL) || (e->name == NULL)) {

        ENGINEerr(ENGINE_F_ENGINE_ADD, ENGINE_R_ID_OR_NAME_MISSING);

        return 0;

    }

    CRYPTO_w_lock(CRYPTO_LOCK_ENGINE);

    if (!engine_list_add(e)) {

        ENGINEerr(ENGINE_F_ENGINE_ADD, ENGINE_R_INTERNAL_LIST_ERROR);

        to_return = 0;

    }

    CRYPTO_w_unlock(CRYPTO_LOCK_ENGINE);

    return to_return;

}

/* Remove an existing "ENGINE" type from the array. */

int ENGINE_remove(ENGINE *e)

{

    int to_return = 1;

    if (e == NULL) {

        ENGINEerr(ENGINE_F_ENGINE_REMOVE, ERR_R_PASSED_NULL_PARAMETER);

        return 0;

    }

    CRYPTO_w_lock(CRYPTO_LOCK_ENGINE);

    if (!engine_list_remove(e)) {

        ENGINEerr(ENGINE_F_ENGINE_REMOVE, ENGINE_R_INTERNAL_LIST_ERROR);

        to_return = 0;

    }

    CRYPTO_w_unlock(CRYPTO_LOCK_ENGINE);

    return to_return;

}

static void engine_cpy(ENGINE *dest, const ENGINE *src)

{

    dest->id = src->id;

    dest->name = src->name;

#ifndef OPENSSL_NO_RSA

    dest->rsa_meth = src->rsa_meth;

#endif

#ifndef OPENSSL_NO_DSA

    dest->dsa_meth = src->dsa_meth;

#endif

#ifndef OPENSSL_NO_DH

    dest->dh_meth = src->dh_meth;

#endif

#ifndef OPENSSL_NO_ECDH

    dest->ecdh_meth = src->ecdh_meth;

#endif

#ifndef OPENSSL_NO_ECDSA

    dest->ecdsa_meth = src->ecdsa_meth;

#endif

    dest->rand_meth = src->rand_meth;

    dest->store_meth = src->store_meth;

    dest->ciphers = src->ciphers;

    dest->digests = src->digests;

    dest->pkey_meths = src->pkey_meths;

    dest->destroy = src->destroy;

    dest->init = src->init;

    dest->finish = src->finish;

    dest->ctrl = src->ctrl;

    dest->load_privkey = src->load_privkey;

    dest->load_pubkey = src->load_pubkey;

    dest->cmd_defns = src->cmd_defns;

    dest->flags = src->flags;

}

ENGINE *ENGINE_by_id(const char *id)

{

    ENGINE *iterator;

    char *load_dir = NULL;

    if (id == NULL) {

        ENGINEerr(ENGINE_F_ENGINE_BY_ID, ERR_R_PASSED_NULL_PARAMETER);

        return NULL;

    }

    CRYPTO_w_lock(CRYPTO_LOCK_ENGINE);

    iterator = engine_list_head;

    while (iterator && (strcmp(id, iterator->id) != 0))

        iterator = iterator->next;

    if (iterator) {

        /*

         * We need to return a structural reference. If this is an ENGINE

         * type that returns copies, make a duplicate - otherwise increment

         * the existing ENGINE's reference count.

         */

        if (iterator->flags & ENGINE_FLAGS_BY_ID_COPY) {

            ENGINE *cp = ENGINE_new();

            if (!cp)

                iterator = NULL;

            else {

                engine_cpy(cp, iterator);

                iterator = cp;

            }

        } else {

            iterator->struct_ref++;

            engine_ref_debug(iterator, 0, 1)

        }

    }

    CRYPTO_w_unlock(CRYPTO_LOCK_ENGINE);

#if 0

    if (iterator == NULL) {

        ENGINEerr(ENGINE_F_ENGINE_BY_ID, ENGINE_R_NO_SUCH_ENGINE);

        ERR_add_error_data(2, "id=", id);

    }

    return iterator;

#else

    /* EEK! Experimental code starts */

    if (iterator)

        return iterator;

    /*

     * Prevent infinite recusrion if we're looking for the dynamic engine.

     */

    if (strcmp(id, "dynamic")) {

# ifdef OPENSSL_SYS_VMS

        if ((load_dir = getenv("OPENSSL_ENGINES")) == 0)

            load_dir = "SSLROOT:[ENGINES]";

# else

        if ((load_dir = getenv("OPENSSL_ENGINES")) == 0)

            load_dir = ENGINESDIR;

# endif

        iterator = ENGINE_by_id("dynamic");

        if (!iterator || !ENGINE_ctrl_cmd_string(iterator, "ID", id, 0) ||

            !ENGINE_ctrl_cmd_string(iterator, "DIR_LOAD", "2", 0) ||

            !ENGINE_ctrl_cmd_string(iterator, "DIR_ADD",

                                    load_dir, 0) ||

            !ENGINE_ctrl_cmd_string(iterator, "LIST_ADD", "1", 0) ||

            !ENGINE_ctrl_cmd_string(iterator, "LOAD", NULL, 0))

            goto notfound;

        return iterator;

    }

 notfound:

    ENGINE_free(iterator);

    ENGINEerr(ENGINE_F_ENGINE_BY_ID, ENGINE_R_NO_SUCH_ENGINE);

    ERR_add_error_data(2, "id=", id);

    return NULL;

    /* EEK! Experimental code ends */

#endif

}

int ENGINE_up_ref(ENGINE *e)

{

    if (e == NULL) {

        ENGINEerr(ENGINE_F_ENGINE_UP_REF, ERR_R_PASSED_NULL_PARAMETER);

        return 0;

    }

    CRYPTO_add(&e->struct_ref, 1, CRYPTO_LOCK_ENGINE);

    return 1;

}