crypto/engine/eng_list.c - third_party/openssl - Git at Google

 /* 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).
  *
  */

 #include <openssl/crypto.h>
 #include "cryptlib.h"
 #include "eng_int.h"
 #include <openssl/engine.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;
 /* A boolean switch, used to ensure we only initialise once. This
  * is needed because the engine list may genuinely become empty during
  * use (so we can't use engine_list_head as an indicator for example. */
 static int engine_list_flag = 0;
 static int ENGINE_free_util(ENGINE *e, int locked);

 /* 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;
 		}
 	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;
 	}

 /* This check always takes place with CRYPTO_LOCK_ENGINE locked up
  * so we're synchronised, but we can't call anything that tries to
  * lock it again! :-) NB: For convenience (and code-clarity) we
  * don't output errors for failures of the engine_list_add function
  * as it will generate errors itself. */
 static int engine_internal_check(void)
 	{
 	int toret = 1;
 	ENGINE *def_engine1, *def_engine2;
 	if(engine_list_flag)
 		return 1;
 	/* This is our first time up, we need to populate the list
 	 * with our statically compiled-in engines. */
 	def_engine1 = ENGINE_openssl();
 	def_engine2 = ENGINE_dynamic();
 	if(!engine_list_add(def_engine1) ||
 			!engine_list_add(def_engine2))
 		toret = 0;
 	else
 		engine_list_flag = 1;
 	ENGINE_free_util(def_engine1, 0);
 	ENGINE_free_util(def_engine2, 0);
 	return 1;
 	}

 /* Get the first/last "ENGINE" type available. */
 ENGINE *ENGINE_get_first(void)
 	{
 	ENGINE *ret = NULL;

 	CRYPTO_r_lock(CRYPTO_LOCK_ENGINE);
 	if(engine_internal_check())
 		{
 		ret = engine_list_head;
 		if(ret)
 			{
 			ret->struct_ref++;
 			engine_ref_debug(ret, 0, 1)
 			}
 		}
 	CRYPTO_r_unlock(CRYPTO_LOCK_ENGINE);
 	return ret;
 	}
 ENGINE *ENGINE_get_last(void)
 	{
 	ENGINE *ret = NULL;

 	CRYPTO_r_lock(CRYPTO_LOCK_ENGINE);
 	if(engine_internal_check())
 		{
 		ret = engine_list_tail;
 		if(ret)
 			{
 			ret->struct_ref++;
 			engine_ref_debug(ret, 0, 1)
 			}
 		}
 	CRYPTO_r_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_r_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_r_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_r_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_r_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);
 		}
 	CRYPTO_w_lock(CRYPTO_LOCK_ENGINE);
 	if(!engine_internal_check() || !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_internal_check() || !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;
 	}

 ENGINE *ENGINE_by_id(const char *id)
 	{
 	ENGINE *iterator = NULL, *cp = NULL;
 	if(id == NULL)
 		{
 		ENGINEerr(ENGINE_F_ENGINE_BY_ID,
 			ERR_R_PASSED_NULL_PARAMETER);
 		return NULL;
 		}
 	CRYPTO_r_lock(CRYPTO_LOCK_ENGINE);
 	if(!engine_internal_check())
 		ENGINEerr(ENGINE_F_ENGINE_BY_ID,
 			ENGINE_R_INTERNAL_LIST_ERROR);
 	else
 		{
 		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
 			 * a "dynamic" ENGINE type, make a duplicate - otherwise
 			 * increment the existing ENGINE's reference count. */
 			if(iterator->flags & ENGINE_FLAGS_BY_ID_COPY)
 				{
 				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_r_unlock(CRYPTO_LOCK_ENGINE);
 	if(iterator == NULL)
 		ENGINEerr(ENGINE_F_ENGINE_BY_ID,
 			ENGINE_R_NO_SUCH_ENGINE);
 	return iterator;
 	}

 ENGINE *ENGINE_new(void)
 	{
 	ENGINE *ret;

 	ret = (ENGINE *)OPENSSL_malloc(sizeof(ENGINE));
 	if(ret == NULL)
 		{
 		ENGINEerr(ENGINE_F_ENGINE_NEW, ERR_R_MALLOC_FAILURE);
 		return NULL;
 		}
 	memset(ret, 0, sizeof(ENGINE));
 	ret->struct_ref = 1;
 	engine_ref_debug(ret, 0, 1)
 	CRYPTO_new_ex_data(CRYPTO_EX_INDEX_ENGINE, ret, &ret->ex_data);
 	return ret;
 	}

 static int ENGINE_free_util(ENGINE *e, int locked)
 	{
 	int i;

 	if(e == NULL)
 		{
 		ENGINEerr(ENGINE_F_ENGINE_FREE,
 			ERR_R_PASSED_NULL_PARAMETER);
 		return 0;
 		}
 	if(locked)
 		i = CRYPTO_add(&e->struct_ref,-1,CRYPTO_LOCK_ENGINE);
 	else
 		i = --e->struct_ref;
 	engine_ref_debug(e, 0, -1)
 	if (i > 0) return 1;
 #ifdef REF_CHECK
 	if (i < 0)
 		{
 		fprintf(stderr,"ENGINE_free, bad structural reference count\n");
 		abort();
 		}
 #endif
 	/* Give the ENGINE a chance to do any structural cleanup corresponding
 	 * to allocation it did in its constructor (eg. unload error strings) */
 	if(e->destroy)
 		e->destroy(e);
 	sk_ENGINE_EVP_CIPHER_pop_free(e->ciphers,ENGINE_free_engine_cipher);
 	CRYPTO_free_ex_data(CRYPTO_EX_INDEX_ENGINE, e, &e->ex_data);
 	OPENSSL_free(e);
 	return 1;
 	}

 int ENGINE_free(ENGINE *e)
 	{
 	return ENGINE_free_util(e, 1);
 	}

 int ENGINE_get_ex_new_index(long argl, void *argp, CRYPTO_EX_new *new_func,
 		CRYPTO_EX_dup *dup_func, CRYPTO_EX_free *free_func)
 	{
 	return CRYPTO_get_ex_new_index(CRYPTO_EX_INDEX_ENGINE, argl, argp,
 			new_func, dup_func, free_func);
 	}

 int ENGINE_set_ex_data(ENGINE *e, int idx, void *arg)
 	{
 	return(CRYPTO_set_ex_data(&e->ex_data, idx, arg));
 	}

 void *ENGINE_get_ex_data(const ENGINE *e, int idx)
 	{
 	return(CRYPTO_get_ex_data(&e->ex_data, idx));
 	}

 void ENGINE_cleanup(void)
 	{
 	ENGINE *iterator = engine_list_head;

 	while(iterator != NULL)
 		{
 		ENGINE_remove(iterator);
 		iterator = engine_list_head;
 		}
 	engine_list_flag = 0;
 	/* Also unset any "default" ENGINEs that may have been set up (a default
 	 * constitutes a functional reference on an ENGINE and there's one for
 	 * each algorithm). */
 	ENGINE_clear_defaults();
 	return;
 	}

 int ENGINE_set_id(ENGINE *e, const char *id)
 	{
 	if(id == NULL)
 		{
 		ENGINEerr(ENGINE_F_ENGINE_SET_ID,
 			ERR_R_PASSED_NULL_PARAMETER);
 		return 0;
 		}
 	e->id = id;
 	return 1;
 	}

 int ENGINE_set_name(ENGINE *e, const char *name)
 	{
 	if(name == NULL)
 		{
 		ENGINEerr(ENGINE_F_ENGINE_SET_NAME,
 			ERR_R_PASSED_NULL_PARAMETER);
 		return 0;
 		}
 	e->name = name;
 	return 1;
 	}

 int ENGINE_set_RSA(ENGINE *e, const RSA_METHOD *rsa_meth)
 	{
 #ifndef OPENSSL_NO_RSA
 	e->rsa_meth = rsa_meth;
 	return 1;
 #else
 	return 0;
 #endif
 	}

 int ENGINE_set_DSA(ENGINE *e, const DSA_METHOD *dsa_meth)
 	{
 #ifndef OPENSSL_NO_DSA
 	e->dsa_meth = dsa_meth;
 	return 1;
 #else
 	return 0;
 #endif
 	}

 int ENGINE_set_DH(ENGINE *e, const DH_METHOD *dh_meth)
 	{
 #ifndef OPENSSL_NO_DH
 	e->dh_meth = dh_meth;
 	return 1;
 #else
 	return 0;
 #endif
 	}

 int ENGINE_set_RAND(ENGINE *e, const RAND_METHOD *rand_meth)
 	{
 	e->rand_meth = rand_meth;
 	return 1;
 	}

 int ENGINE_set_BN_mod_exp(ENGINE *e, BN_MOD_EXP bn_mod_exp)
 	{
 	e->bn_mod_exp = bn_mod_exp;
 	return 1;
 	}

 int ENGINE_set_BN_mod_exp_crt(ENGINE *e, BN_MOD_EXP_CRT bn_mod_exp_crt)
 	{
 	e->bn_mod_exp_crt = bn_mod_exp_crt;
 	return 1;
 	}

 int ENGINE_set_destroy_function(ENGINE *e, ENGINE_GEN_INT_FUNC_PTR destroy_f)
 	{
 	e->destroy = destroy_f;
 	return 1;
 	}

 int ENGINE_set_init_function(ENGINE *e, ENGINE_GEN_INT_FUNC_PTR init_f)
 	{
 	e->init = init_f;
 	return 1;
 	}

 int ENGINE_set_finish_function(ENGINE *e, ENGINE_GEN_INT_FUNC_PTR finish_f)
 	{
 	e->finish = finish_f;
 	return 1;
 	}

 int ENGINE_set_ctrl_function(ENGINE *e, ENGINE_CTRL_FUNC_PTR ctrl_f)
 	{
 	e->ctrl = ctrl_f;
 	return 1;
 	}

 int ENGINE_set_load_privkey_function(ENGINE *e, ENGINE_LOAD_KEY_PTR loadpriv_f)
 	{
 	e->load_privkey = loadpriv_f;
 	return 1;
 	}

 int ENGINE_set_load_pubkey_function(ENGINE *e, ENGINE_LOAD_KEY_PTR loadpub_f)
 	{
 	e->load_pubkey = loadpub_f;
 	return 1;
 	}

 int ENGINE_set_flags(ENGINE *e, int flags)
 	{
 	e->flags = flags;
 	return 1;
 	}

 int ENGINE_set_cmd_defns(ENGINE *e, const ENGINE_CMD_DEFN *defns)
 	{
 	e->cmd_defns = defns;
 	return 1;
 	}

 int ENGINE_cpy(ENGINE *dest, const ENGINE *src)
 	{
 	if(ENGINE_set_id(dest, ENGINE_get_id(src)) &&
 			ENGINE_set_name(dest, ENGINE_get_name(src)) &&
 #ifndef OPENSSL_NO_RSA
 			ENGINE_set_RSA(dest, ENGINE_get_RSA(src)) &&
 #endif
 #ifndef OPENSSL_NO_DSA
 			ENGINE_set_DSA(dest, ENGINE_get_DSA(src)) &&
 #endif
 #ifndef OPENSSL_NO_DH
 			ENGINE_set_DH(dest, ENGINE_get_DH(src)) &&
 #endif
 			ENGINE_set_RAND(dest, ENGINE_get_RAND(src)) &&
 			ENGINE_set_BN_mod_exp(dest,
 					ENGINE_get_BN_mod_exp(src)) &&
 			ENGINE_set_BN_mod_exp_crt(dest,
 					ENGINE_get_BN_mod_exp_crt(src)) &&
 			ENGINE_set_init_function(dest,
 					ENGINE_get_init_function(src)) &&
 			ENGINE_set_finish_function(dest,
 					ENGINE_get_finish_function(src)) &&
 			ENGINE_set_ctrl_function(dest,
 					ENGINE_get_ctrl_function(src)) &&
 			ENGINE_set_load_privkey_function(dest,
 					ENGINE_get_load_privkey_function(src)) &&
 			ENGINE_set_load_pubkey_function(dest,
 					ENGINE_get_load_pubkey_function(src)) &&
 			ENGINE_set_flags(dest, ENGINE_get_flags(src)) &&
 			ENGINE_set_cmd_defns(dest, ENGINE_get_cmd_defns(src)))
 		return 1;
 	return 0;
 	}

 const char *ENGINE_get_id(const ENGINE *e)
 	{
 	return e->id;
 	}

 const char *ENGINE_get_name(const ENGINE *e)
 	{
 	return e->name;
 	}

 const RSA_METHOD *ENGINE_get_RSA(const ENGINE *e)
 	{
 	return e->rsa_meth;
 	}

 const DSA_METHOD *ENGINE_get_DSA(const ENGINE *e)
 	{
 	return e->dsa_meth;
 	}

 const DH_METHOD *ENGINE_get_DH(const ENGINE *e)
 	{
 	return e->dh_meth;
 	}

 const RAND_METHOD *ENGINE_get_RAND(const ENGINE *e)
 	{
 	return e->rand_meth;
 	}

 BN_MOD_EXP ENGINE_get_BN_mod_exp(const ENGINE *e)
 	{
 	return e->bn_mod_exp;
 	}

 BN_MOD_EXP_CRT ENGINE_get_BN_mod_exp_crt(const ENGINE *e)
 	{
 	return e->bn_mod_exp_crt;
 	}

 ENGINE_GEN_INT_FUNC_PTR ENGINE_get_destroy_function(const ENGINE *e)
 	{
 	return e->destroy;
 	}

 ENGINE_GEN_INT_FUNC_PTR ENGINE_get_init_function(const ENGINE *e)
 	{
 	return e->init;
 	}

 ENGINE_GEN_INT_FUNC_PTR ENGINE_get_finish_function(const ENGINE *e)
 	{
 	return e->finish;
 	}

 ENGINE_CTRL_FUNC_PTR ENGINE_get_ctrl_function(const ENGINE *e)
 	{
 	return e->ctrl;
 	}

 ENGINE_LOAD_KEY_PTR ENGINE_get_load_privkey_function(const ENGINE *e)
 	{
 	return e->load_privkey;
 	}

 ENGINE_LOAD_KEY_PTR ENGINE_get_load_pubkey_function(const ENGINE *e)
 	{
 	return e->load_pubkey;
 	}

 int ENGINE_get_flags(const ENGINE *e)
 	{
 	return e->flags;
 	}

 const ENGINE_CMD_DEFN *ENGINE_get_cmd_defns(const ENGINE *e)
 	{
 	return e->cmd_defns;
 	}
	/* 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).
	*
	*/

	#include <openssl/crypto.h>
	#include "cryptlib.h"
	#include "eng_int.h"
	#include <openssl/engine.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;
	/* A boolean switch, used to ensure we only initialise once. This
	* is needed because the engine list may genuinely become empty during
	* use (so we can't use engine_list_head as an indicator for example. */
	static int engine_list_flag = 0;
	static int ENGINE_free_util(ENGINE *e, int locked);

	/* 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;
	}
	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;
	}

	/* This check always takes place with CRYPTO_LOCK_ENGINE locked up
	* so we're synchronised, but we can't call anything that tries to
	* lock it again! :-) NB: For convenience (and code-clarity) we
	* don't output errors for failures of the engine_list_add function
	* as it will generate errors itself. */
	static int engine_internal_check(void)
	{
	int toret = 1;
	ENGINE def_engine1, def_engine2;
	if(engine_list_flag)
	return 1;
	/* This is our first time up, we need to populate the list
	* with our statically compiled-in engines. */
	def_engine1 = ENGINE_openssl();
	def_engine2 = ENGINE_dynamic();
	if(!engine_list_add(def_engine1) \|\|
	!engine_list_add(def_engine2))
	toret = 0;
	else
	engine_list_flag = 1;
	ENGINE_free_util(def_engine1, 0);
	ENGINE_free_util(def_engine2, 0);
	return 1;
	}

	/* Get the first/last "ENGINE" type available. */
	ENGINE *ENGINE_get_first(void)
	{
	ENGINE *ret = NULL;

	CRYPTO_r_lock(CRYPTO_LOCK_ENGINE);
	if(engine_internal_check())
	{
	ret = engine_list_head;
	if(ret)
	{
	ret->struct_ref++;
	engine_ref_debug(ret, 0, 1)
	}
	}
	CRYPTO_r_unlock(CRYPTO_LOCK_ENGINE);
	return ret;
	}
	ENGINE *ENGINE_get_last(void)
	{
	ENGINE *ret = NULL;

	CRYPTO_r_lock(CRYPTO_LOCK_ENGINE);
	if(engine_internal_check())
	{
	ret = engine_list_tail;
	if(ret)
	{
	ret->struct_ref++;
	engine_ref_debug(ret, 0, 1)
	}
	}
	CRYPTO_r_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_r_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_r_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_r_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_r_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);
	}
	CRYPTO_w_lock(CRYPTO_LOCK_ENGINE);
	if(!engine_internal_check() \|\| !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_internal_check() \|\| !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;
	}

	ENGINE ENGINE_by_id(const char id)
	{
	ENGINE iterator = NULL, cp = NULL;
	if(id == NULL)
	{
	ENGINEerr(ENGINE_F_ENGINE_BY_ID,
	ERR_R_PASSED_NULL_PARAMETER);
	return NULL;
	}
	CRYPTO_r_lock(CRYPTO_LOCK_ENGINE);
	if(!engine_internal_check())
	ENGINEerr(ENGINE_F_ENGINE_BY_ID,
	ENGINE_R_INTERNAL_LIST_ERROR);
	else
	{
	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
	* a "dynamic" ENGINE type, make a duplicate - otherwise
	* increment the existing ENGINE's reference count. */
	if(iterator->flags & ENGINE_FLAGS_BY_ID_COPY)
	{
	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_r_unlock(CRYPTO_LOCK_ENGINE);
	if(iterator == NULL)
	ENGINEerr(ENGINE_F_ENGINE_BY_ID,
	ENGINE_R_NO_SUCH_ENGINE);
	return iterator;
	}

	ENGINE *ENGINE_new(void)
	{
	ENGINE *ret;

	ret = (ENGINE *)OPENSSL_malloc(sizeof(ENGINE));
	if(ret == NULL)
	{
	ENGINEerr(ENGINE_F_ENGINE_NEW, ERR_R_MALLOC_FAILURE);
	return NULL;
	}
	memset(ret, 0, sizeof(ENGINE));
	ret->struct_ref = 1;
	engine_ref_debug(ret, 0, 1)
	CRYPTO_new_ex_data(CRYPTO_EX_INDEX_ENGINE, ret, &ret->ex_data);
	return ret;
	}

	static int ENGINE_free_util(ENGINE *e, int locked)
	{
	int i;

	if(e == NULL)
	{
	ENGINEerr(ENGINE_F_ENGINE_FREE,
	ERR_R_PASSED_NULL_PARAMETER);
	return 0;
	}
	if(locked)
	i = CRYPTO_add(&e->struct_ref,-1,CRYPTO_LOCK_ENGINE);
	else
	i = --e->struct_ref;
	engine_ref_debug(e, 0, -1)
	if (i > 0) return 1;
	#ifdef REF_CHECK
	if (i < 0)
	{
	fprintf(stderr,"ENGINE_free, bad structural reference count\n");
	abort();
	}
	#endif
	/* Give the ENGINE a chance to do any structural cleanup corresponding
	* to allocation it did in its constructor (eg. unload error strings) */
	if(e->destroy)
	e->destroy(e);
	sk_ENGINE_EVP_CIPHER_pop_free(e->ciphers,ENGINE_free_engine_cipher);
	CRYPTO_free_ex_data(CRYPTO_EX_INDEX_ENGINE, e, &e->ex_data);
	OPENSSL_free(e);
	return 1;
	}

	int ENGINE_free(ENGINE *e)
	{
	return ENGINE_free_util(e, 1);
	}

	int ENGINE_get_ex_new_index(long argl, void argp, CRYPTO_EX_new new_func,
	CRYPTO_EX_dup dup_func, CRYPTO_EX_free free_func)
	{
	return CRYPTO_get_ex_new_index(CRYPTO_EX_INDEX_ENGINE, argl, argp,
	new_func, dup_func, free_func);
	}

	int ENGINE_set_ex_data(ENGINE e, int idx, void arg)
	{
	return(CRYPTO_set_ex_data(&e->ex_data, idx, arg));
	}

	void ENGINE_get_ex_data(const ENGINE e, int idx)
	{
	return(CRYPTO_get_ex_data(&e->ex_data, idx));
	}

	void ENGINE_cleanup(void)
	{
	ENGINE *iterator = engine_list_head;

	while(iterator != NULL)
	{
	ENGINE_remove(iterator);
	iterator = engine_list_head;
	}
	engine_list_flag = 0;
	/* Also unset any "default" ENGINEs that may have been set up (a default
	* constitutes a functional reference on an ENGINE and there's one for
	* each algorithm). */
	ENGINE_clear_defaults();
	return;
	}

	int ENGINE_set_id(ENGINE e, const char id)
	{
	if(id == NULL)
	{
	ENGINEerr(ENGINE_F_ENGINE_SET_ID,
	ERR_R_PASSED_NULL_PARAMETER);
	return 0;
	}
	e->id = id;
	return 1;
	}

	int ENGINE_set_name(ENGINE e, const char name)
	{
	if(name == NULL)
	{
	ENGINEerr(ENGINE_F_ENGINE_SET_NAME,
	ERR_R_PASSED_NULL_PARAMETER);
	return 0;
	}
	e->name = name;
	return 1;
	}

	int ENGINE_set_RSA(ENGINE e, const RSA_METHOD rsa_meth)
	{
	#ifndef OPENSSL_NO_RSA
	e->rsa_meth = rsa_meth;
	return 1;
	#else
	return 0;
	#endif
	}

	int ENGINE_set_DSA(ENGINE e, const DSA_METHOD dsa_meth)
	{
	#ifndef OPENSSL_NO_DSA
	e->dsa_meth = dsa_meth;
	return 1;
	#else
	return 0;
	#endif
	}

	int ENGINE_set_DH(ENGINE e, const DH_METHOD dh_meth)
	{
	#ifndef OPENSSL_NO_DH
	e->dh_meth = dh_meth;
	return 1;
	#else
	return 0;
	#endif
	}

	int ENGINE_set_RAND(ENGINE e, const RAND_METHOD rand_meth)
	{
	e->rand_meth = rand_meth;
	return 1;
	}

	int ENGINE_set_BN_mod_exp(ENGINE *e, BN_MOD_EXP bn_mod_exp)
	{
	e->bn_mod_exp = bn_mod_exp;
	return 1;
	}

	int ENGINE_set_BN_mod_exp_crt(ENGINE *e, BN_MOD_EXP_CRT bn_mod_exp_crt)
	{
	e->bn_mod_exp_crt = bn_mod_exp_crt;
	return 1;
	}

	int ENGINE_set_destroy_function(ENGINE *e, ENGINE_GEN_INT_FUNC_PTR destroy_f)
	{
	e->destroy = destroy_f;
	return 1;
	}

	int ENGINE_set_init_function(ENGINE *e, ENGINE_GEN_INT_FUNC_PTR init_f)
	{
	e->init = init_f;
	return 1;
	}

	int ENGINE_set_finish_function(ENGINE *e, ENGINE_GEN_INT_FUNC_PTR finish_f)
	{
	e->finish = finish_f;
	return 1;
	}

	int ENGINE_set_ctrl_function(ENGINE *e, ENGINE_CTRL_FUNC_PTR ctrl_f)
	{
	e->ctrl = ctrl_f;
	return 1;
	}

	int ENGINE_set_load_privkey_function(ENGINE *e, ENGINE_LOAD_KEY_PTR loadpriv_f)
	{
	e->load_privkey = loadpriv_f;
	return 1;
	}

	int ENGINE_set_load_pubkey_function(ENGINE *e, ENGINE_LOAD_KEY_PTR loadpub_f)
	{
	e->load_pubkey = loadpub_f;
	return 1;
	}

	int ENGINE_set_flags(ENGINE *e, int flags)
	{
	e->flags = flags;
	return 1;
	}

	int ENGINE_set_cmd_defns(ENGINE e, const ENGINE_CMD_DEFN defns)
	{
	e->cmd_defns = defns;
	return 1;
	}

	int ENGINE_cpy(ENGINE dest, const ENGINE src)
	{
	if(ENGINE_set_id(dest, ENGINE_get_id(src)) &&
	ENGINE_set_name(dest, ENGINE_get_name(src)) &&
	#ifndef OPENSSL_NO_RSA
	ENGINE_set_RSA(dest, ENGINE_get_RSA(src)) &&
	#endif
	#ifndef OPENSSL_NO_DSA
	ENGINE_set_DSA(dest, ENGINE_get_DSA(src)) &&
	#endif
	#ifndef OPENSSL_NO_DH
	ENGINE_set_DH(dest, ENGINE_get_DH(src)) &&
	#endif
	ENGINE_set_RAND(dest, ENGINE_get_RAND(src)) &&
	ENGINE_set_BN_mod_exp(dest,
	ENGINE_get_BN_mod_exp(src)) &&
	ENGINE_set_BN_mod_exp_crt(dest,
	ENGINE_get_BN_mod_exp_crt(src)) &&
	ENGINE_set_init_function(dest,
	ENGINE_get_init_function(src)) &&
	ENGINE_set_finish_function(dest,
	ENGINE_get_finish_function(src)) &&
	ENGINE_set_ctrl_function(dest,
	ENGINE_get_ctrl_function(src)) &&
	ENGINE_set_load_privkey_function(dest,
	ENGINE_get_load_privkey_function(src)) &&
	ENGINE_set_load_pubkey_function(dest,
	ENGINE_get_load_pubkey_function(src)) &&
	ENGINE_set_flags(dest, ENGINE_get_flags(src)) &&
	ENGINE_set_cmd_defns(dest, ENGINE_get_cmd_defns(src)))
	return 1;
	return 0;
	}

	const char ENGINE_get_id(const ENGINE e)
	{
	return e->id;
	}

	const char ENGINE_get_name(const ENGINE e)
	{
	return e->name;
	}

	const RSA_METHOD ENGINE_get_RSA(const ENGINE e)
	{
	return e->rsa_meth;
	}

	const DSA_METHOD ENGINE_get_DSA(const ENGINE e)
	{
	return e->dsa_meth;
	}

	const DH_METHOD ENGINE_get_DH(const ENGINE e)
	{
	return e->dh_meth;
	}

	const RAND_METHOD ENGINE_get_RAND(const ENGINE e)
	{
	return e->rand_meth;
	}

	BN_MOD_EXP ENGINE_get_BN_mod_exp(const ENGINE *e)
	{
	return e->bn_mod_exp;
	}

	BN_MOD_EXP_CRT ENGINE_get_BN_mod_exp_crt(const ENGINE *e)
	{
	return e->bn_mod_exp_crt;
	}

	ENGINE_GEN_INT_FUNC_PTR ENGINE_get_destroy_function(const ENGINE *e)
	{
	return e->destroy;
	}

	ENGINE_GEN_INT_FUNC_PTR ENGINE_get_init_function(const ENGINE *e)
	{
	return e->init;
	}

	ENGINE_GEN_INT_FUNC_PTR ENGINE_get_finish_function(const ENGINE *e)
	{
	return e->finish;
	}

	ENGINE_CTRL_FUNC_PTR ENGINE_get_ctrl_function(const ENGINE *e)
	{
	return e->ctrl;
	}

	ENGINE_LOAD_KEY_PTR ENGINE_get_load_privkey_function(const ENGINE *e)
	{
	return e->load_privkey;
	}

	ENGINE_LOAD_KEY_PTR ENGINE_get_load_pubkey_function(const ENGINE *e)
	{
	return e->load_pubkey;
	}

	int ENGINE_get_flags(const ENGINE *e)
	{
	return e->flags;
	}

	const ENGINE_CMD_DEFN ENGINE_get_cmd_defns(const ENGINE e)
	{
	return e->cmd_defns;
	}