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

 /*
  * Copyright 2001-2021 The OpenSSL Project Authors. All Rights Reserved.
  * Copyright (c) 2002, Oracle and/or its affiliates. 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
  */

 /* We need to use some engine deprecated APIs */
 #define OPENSSL_SUPPRESS_DEPRECATED

 #include "eng_local.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 optimization 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;

 /*
  * The linked list of currently loaded dynamic engines.
  */
 static ENGINE *engine_dyn_list_head = NULL;
 static ENGINE *engine_dyn_list_tail = NULL;

 /*
  * This cleanup function is only needed internally. If it should be called,
  * we register it with the "engine_cleanup_int()" 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 global_engine_lock has been locked up.
  */
 static int engine_list_add(ENGINE *e)
 {
     int conflict = 0;
     ENGINE *iterator = NULL;

     if (e == NULL) {
         ERR_raise(ERR_LIB_ENGINE, 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) {
         ERR_raise(ERR_LIB_ENGINE, ENGINE_R_CONFLICTING_ENGINE_ID);
         return 0;
     }
     if (engine_list_head == NULL) {
         /* We are adding to an empty list. */
         if (engine_list_tail) {
             ERR_raise(ERR_LIB_ENGINE, 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)) {
             ERR_raise(ERR_LIB_ENGINE, 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_PRINT(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) {
         ERR_raise(ERR_LIB_ENGINE, 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) {
         ERR_raise(ERR_LIB_ENGINE, 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;
 }

 /* Add engine to dynamic engine list. */
 int engine_add_dynamic_id(ENGINE *e, ENGINE_DYNAMIC_ID dynamic_id,
                           int not_locked)
 {
     int result = 0;
     ENGINE *iterator = NULL;

     if (e == NULL)
         return 0;

     if (e->dynamic_id == NULL && dynamic_id == NULL)
         return 0;

     if (not_locked && !CRYPTO_THREAD_write_lock(global_engine_lock))
         return 0;

     if (dynamic_id != NULL) {
         iterator = engine_dyn_list_head;
         while (iterator != NULL) {
             if (iterator->dynamic_id == dynamic_id)
                 goto err;
             iterator = iterator->next;
         }
         if (e->dynamic_id != NULL)
             goto err;
         e->dynamic_id = dynamic_id;
     }

     if (engine_dyn_list_head == NULL) {
         /* We are adding to an empty list. */
         if (engine_dyn_list_tail != NULL)
             goto err;
         engine_dyn_list_head = e;
         e->prev_dyn = NULL;
     } else {
         /* We are adding to the tail of an existing list. */
         if (engine_dyn_list_tail == NULL
             || engine_dyn_list_tail->next_dyn != NULL)
             goto err;
         engine_dyn_list_tail->next_dyn = e;
         e->prev_dyn = engine_dyn_list_tail;
     }

     engine_dyn_list_tail = e;
     e->next_dyn = NULL;
     result = 1;

  err:
     if (not_locked)
         CRYPTO_THREAD_unlock(global_engine_lock);
     return result;
 }

 /* Remove engine from dynamic engine list. */
 void engine_remove_dynamic_id(ENGINE *e, int not_locked)
 {
     if (e == NULL || e->dynamic_id == NULL)
         return;

     if (not_locked && !CRYPTO_THREAD_write_lock(global_engine_lock))
         return;

     e->dynamic_id = NULL;

     /* un-link e from the chain. */
     if (e->next_dyn != NULL)
         e->next_dyn->prev_dyn = e->prev_dyn;
     if (e->prev_dyn != NULL)
         e->prev_dyn->next_dyn = e->next_dyn;
     /* Correct our head/tail if necessary. */
     if (engine_dyn_list_head == e)
         engine_dyn_list_head = e->next_dyn;
     if (engine_dyn_list_tail == e)
         engine_dyn_list_tail = e->prev_dyn;

     if (not_locked)
         CRYPTO_THREAD_unlock(global_engine_lock);
 }

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

     if (!RUN_ONCE(&engine_lock_init, do_engine_lock_init)) {
         ERR_raise(ERR_LIB_ENGINE, ERR_R_MALLOC_FAILURE);
         return NULL;
     }

     if (!CRYPTO_THREAD_write_lock(global_engine_lock))
         return NULL;
     ret = engine_list_head;
     if (ret) {
         ret->struct_ref++;
         ENGINE_REF_PRINT(ret, 0, 1);
     }
     CRYPTO_THREAD_unlock(global_engine_lock);
     return ret;
 }

 ENGINE *ENGINE_get_last(void)
 {
     ENGINE *ret;

     if (!RUN_ONCE(&engine_lock_init, do_engine_lock_init)) {
         ERR_raise(ERR_LIB_ENGINE, ERR_R_MALLOC_FAILURE);
         return NULL;
     }

     if (!CRYPTO_THREAD_write_lock(global_engine_lock))
         return NULL;
     ret = engine_list_tail;
     if (ret) {
         ret->struct_ref++;
         ENGINE_REF_PRINT(ret, 0, 1);
     }
     CRYPTO_THREAD_unlock(global_engine_lock);
     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) {
         ERR_raise(ERR_LIB_ENGINE, ERR_R_PASSED_NULL_PARAMETER);
         return NULL;
     }
     if (!CRYPTO_THREAD_write_lock(global_engine_lock))
         return NULL;
     ret = e->next;
     if (ret) {
         /* Return a valid structural reference to the next ENGINE */
         ret->struct_ref++;
         ENGINE_REF_PRINT(ret, 0, 1);
     }
     CRYPTO_THREAD_unlock(global_engine_lock);
     /* 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) {
         ERR_raise(ERR_LIB_ENGINE, ERR_R_PASSED_NULL_PARAMETER);
         return NULL;
     }
     if (!CRYPTO_THREAD_write_lock(global_engine_lock))
         return NULL;
     ret = e->prev;
     if (ret) {
         /* Return a valid structural reference to the next ENGINE */
         ret->struct_ref++;
         ENGINE_REF_PRINT(ret, 0, 1);
     }
     CRYPTO_THREAD_unlock(global_engine_lock);
     /* 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) {
         ERR_raise(ERR_LIB_ENGINE, ERR_R_PASSED_NULL_PARAMETER);
         return 0;
     }
     if ((e->id == NULL) || (e->name == NULL)) {
         ERR_raise(ERR_LIB_ENGINE, ENGINE_R_ID_OR_NAME_MISSING);
         return 0;
     }
     if (!CRYPTO_THREAD_write_lock(global_engine_lock))
         return 0;
     if (!engine_list_add(e)) {
         ERR_raise(ERR_LIB_ENGINE, ENGINE_R_INTERNAL_LIST_ERROR);
         to_return = 0;
     }
     CRYPTO_THREAD_unlock(global_engine_lock);
     return to_return;
 }

 /* Remove an existing "ENGINE" type from the array. */
 int ENGINE_remove(ENGINE *e)
 {
     int to_return = 1;
     if (e == NULL) {
         ERR_raise(ERR_LIB_ENGINE, ERR_R_PASSED_NULL_PARAMETER);
         return 0;
     }
     if (!CRYPTO_THREAD_write_lock(global_engine_lock))
         return 0;
     if (!engine_list_remove(e)) {
         ERR_raise(ERR_LIB_ENGINE, ENGINE_R_INTERNAL_LIST_ERROR);
         to_return = 0;
     }
     CRYPTO_THREAD_unlock(global_engine_lock);
     return to_return;
 }

 static void engine_cpy(ENGINE *dest, const ENGINE *src)
 {
     dest->id = src->id;
     dest->name = src->name;
     dest->rsa_meth = src->rsa_meth;
 #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_EC
     dest->ec_meth = src->ec_meth;
 #endif
     dest->rand_meth = src->rand_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;
     dest->dynamic_id = src->dynamic_id;
     engine_add_dynamic_id(dest, NULL, 0);
 }

 ENGINE *ENGINE_by_id(const char *id)
 {
     ENGINE *iterator;
     char *load_dir = NULL;
     if (id == NULL) {
         ERR_raise(ERR_LIB_ENGINE, ERR_R_PASSED_NULL_PARAMETER);
         return NULL;
     }
     ENGINE_load_builtin_engines();

     if (!RUN_ONCE(&engine_lock_init, do_engine_lock_init)) {
         ERR_raise(ERR_LIB_ENGINE, ERR_R_MALLOC_FAILURE);
         return NULL;
     }

     if (!CRYPTO_THREAD_write_lock(global_engine_lock))
         return NULL;
     iterator = engine_list_head;
     while (iterator && (strcmp(id, iterator->id) != 0))
         iterator = iterator->next;
     if (iterator != NULL) {
         /*
          * 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 == NULL)
                 iterator = NULL;
             else {
                 engine_cpy(cp, iterator);
                 iterator = cp;
             }
         } else {
             iterator->struct_ref++;
             ENGINE_REF_PRINT(iterator, 0, 1);
         }
     }
     CRYPTO_THREAD_unlock(global_engine_lock);
     if (iterator != NULL)
         return iterator;
     /*
      * Prevent infinite recursion if we're looking for the dynamic engine.
      */
     if (strcmp(id, "dynamic")) {
         if ((load_dir = ossl_safe_getenv("OPENSSL_ENGINES")) == NULL)
             load_dir = ENGINESDIR;
         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);
     ERR_raise_data(ERR_LIB_ENGINE, ENGINE_R_NO_SUCH_ENGINE, "id=%s", id);
     return NULL;
     /* EEK! Experimental code ends */
 }

 int ENGINE_up_ref(ENGINE *e)
 {
     int i;
     if (e == NULL) {
         ERR_raise(ERR_LIB_ENGINE, ERR_R_PASSED_NULL_PARAMETER);
         return 0;
     }
     CRYPTO_UP_REF(&e->struct_ref, &i, global_engine_lock);
     return 1;
 }
	/*
	* Copyright 2001-2021 The OpenSSL Project Authors. All Rights Reserved.
	* Copyright (c) 2002, Oracle and/or its affiliates. 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
	*/

	/* We need to use some engine deprecated APIs */
	#define OPENSSL_SUPPRESS_DEPRECATED

	#include "eng_local.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 optimization 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;

	/*
	* The linked list of currently loaded dynamic engines.
	*/
	static ENGINE *engine_dyn_list_head = NULL;
	static ENGINE *engine_dyn_list_tail = NULL;

	/*
	* This cleanup function is only needed internally. If it should be called,
	* we register it with the "engine_cleanup_int()" 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 global_engine_lock has been locked up.
	*/
	static int engine_list_add(ENGINE *e)
	{
	int conflict = 0;
	ENGINE *iterator = NULL;

	if (e == NULL) {
	ERR_raise(ERR_LIB_ENGINE, 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) {
	ERR_raise(ERR_LIB_ENGINE, ENGINE_R_CONFLICTING_ENGINE_ID);
	return 0;
	}
	if (engine_list_head == NULL) {
	/* We are adding to an empty list. */
	if (engine_list_tail) {
	ERR_raise(ERR_LIB_ENGINE, 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)) {
	ERR_raise(ERR_LIB_ENGINE, 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_PRINT(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) {
	ERR_raise(ERR_LIB_ENGINE, 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) {
	ERR_raise(ERR_LIB_ENGINE, 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;
	}

	/* Add engine to dynamic engine list. */
	int engine_add_dynamic_id(ENGINE *e, ENGINE_DYNAMIC_ID dynamic_id,
	int not_locked)
	{
	int result = 0;
	ENGINE *iterator = NULL;

	if (e == NULL)
	return 0;

	if (e->dynamic_id == NULL && dynamic_id == NULL)
	return 0;

	if (not_locked && !CRYPTO_THREAD_write_lock(global_engine_lock))
	return 0;

	if (dynamic_id != NULL) {
	iterator = engine_dyn_list_head;
	while (iterator != NULL) {
	if (iterator->dynamic_id == dynamic_id)
	goto err;
	iterator = iterator->next;
	}
	if (e->dynamic_id != NULL)
	goto err;
	e->dynamic_id = dynamic_id;
	}

	if (engine_dyn_list_head == NULL) {
	/* We are adding to an empty list. */
	if (engine_dyn_list_tail != NULL)
	goto err;
	engine_dyn_list_head = e;
	e->prev_dyn = NULL;
	} else {
	/* We are adding to the tail of an existing list. */
	if (engine_dyn_list_tail == NULL
	\|\| engine_dyn_list_tail->next_dyn != NULL)
	goto err;
	engine_dyn_list_tail->next_dyn = e;
	e->prev_dyn = engine_dyn_list_tail;
	}

	engine_dyn_list_tail = e;
	e->next_dyn = NULL;
	result = 1;

	err:
	if (not_locked)
	CRYPTO_THREAD_unlock(global_engine_lock);
	return result;
	}

	/* Remove engine from dynamic engine list. */
	void engine_remove_dynamic_id(ENGINE *e, int not_locked)
	{
	if (e == NULL \|\| e->dynamic_id == NULL)
	return;

	if (not_locked && !CRYPTO_THREAD_write_lock(global_engine_lock))
	return;

	e->dynamic_id = NULL;

	/* un-link e from the chain. */
	if (e->next_dyn != NULL)
	e->next_dyn->prev_dyn = e->prev_dyn;
	if (e->prev_dyn != NULL)
	e->prev_dyn->next_dyn = e->next_dyn;
	/* Correct our head/tail if necessary. */
	if (engine_dyn_list_head == e)
	engine_dyn_list_head = e->next_dyn;
	if (engine_dyn_list_tail == e)
	engine_dyn_list_tail = e->prev_dyn;

	if (not_locked)
	CRYPTO_THREAD_unlock(global_engine_lock);
	}

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

	if (!RUN_ONCE(&engine_lock_init, do_engine_lock_init)) {
	ERR_raise(ERR_LIB_ENGINE, ERR_R_MALLOC_FAILURE);
	return NULL;
	}

	if (!CRYPTO_THREAD_write_lock(global_engine_lock))
	return NULL;
	ret = engine_list_head;
	if (ret) {
	ret->struct_ref++;
	ENGINE_REF_PRINT(ret, 0, 1);
	}
	CRYPTO_THREAD_unlock(global_engine_lock);
	return ret;
	}

	ENGINE *ENGINE_get_last(void)
	{
	ENGINE *ret;

	if (!RUN_ONCE(&engine_lock_init, do_engine_lock_init)) {
	ERR_raise(ERR_LIB_ENGINE, ERR_R_MALLOC_FAILURE);
	return NULL;
	}

	if (!CRYPTO_THREAD_write_lock(global_engine_lock))
	return NULL;
	ret = engine_list_tail;
	if (ret) {
	ret->struct_ref++;
	ENGINE_REF_PRINT(ret, 0, 1);
	}
	CRYPTO_THREAD_unlock(global_engine_lock);
	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) {
	ERR_raise(ERR_LIB_ENGINE, ERR_R_PASSED_NULL_PARAMETER);
	return NULL;
	}
	if (!CRYPTO_THREAD_write_lock(global_engine_lock))
	return NULL;
	ret = e->next;
	if (ret) {
	/* Return a valid structural reference to the next ENGINE */
	ret->struct_ref++;
	ENGINE_REF_PRINT(ret, 0, 1);
	}
	CRYPTO_THREAD_unlock(global_engine_lock);
	/* 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) {
	ERR_raise(ERR_LIB_ENGINE, ERR_R_PASSED_NULL_PARAMETER);
	return NULL;
	}
	if (!CRYPTO_THREAD_write_lock(global_engine_lock))
	return NULL;
	ret = e->prev;
	if (ret) {
	/* Return a valid structural reference to the next ENGINE */
	ret->struct_ref++;
	ENGINE_REF_PRINT(ret, 0, 1);
	}
	CRYPTO_THREAD_unlock(global_engine_lock);
	/* 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) {
	ERR_raise(ERR_LIB_ENGINE, ERR_R_PASSED_NULL_PARAMETER);
	return 0;
	}
	if ((e->id == NULL) \|\| (e->name == NULL)) {
	ERR_raise(ERR_LIB_ENGINE, ENGINE_R_ID_OR_NAME_MISSING);
	return 0;
	}
	if (!CRYPTO_THREAD_write_lock(global_engine_lock))
	return 0;
	if (!engine_list_add(e)) {
	ERR_raise(ERR_LIB_ENGINE, ENGINE_R_INTERNAL_LIST_ERROR);
	to_return = 0;
	}
	CRYPTO_THREAD_unlock(global_engine_lock);
	return to_return;
	}

	/* Remove an existing "ENGINE" type from the array. */
	int ENGINE_remove(ENGINE *e)
	{
	int to_return = 1;
	if (e == NULL) {
	ERR_raise(ERR_LIB_ENGINE, ERR_R_PASSED_NULL_PARAMETER);
	return 0;
	}
	if (!CRYPTO_THREAD_write_lock(global_engine_lock))
	return 0;
	if (!engine_list_remove(e)) {
	ERR_raise(ERR_LIB_ENGINE, ENGINE_R_INTERNAL_LIST_ERROR);
	to_return = 0;
	}
	CRYPTO_THREAD_unlock(global_engine_lock);
	return to_return;
	}

	static void engine_cpy(ENGINE dest, const ENGINE src)
	{
	dest->id = src->id;
	dest->name = src->name;
	dest->rsa_meth = src->rsa_meth;
	#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_EC
	dest->ec_meth = src->ec_meth;
	#endif
	dest->rand_meth = src->rand_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;
	dest->dynamic_id = src->dynamic_id;
	engine_add_dynamic_id(dest, NULL, 0);
	}

	ENGINE ENGINE_by_id(const char id)
	{
	ENGINE *iterator;
	char *load_dir = NULL;
	if (id == NULL) {
	ERR_raise(ERR_LIB_ENGINE, ERR_R_PASSED_NULL_PARAMETER);
	return NULL;
	}
	ENGINE_load_builtin_engines();

	if (!RUN_ONCE(&engine_lock_init, do_engine_lock_init)) {
	ERR_raise(ERR_LIB_ENGINE, ERR_R_MALLOC_FAILURE);
	return NULL;
	}

	if (!CRYPTO_THREAD_write_lock(global_engine_lock))
	return NULL;
	iterator = engine_list_head;
	while (iterator && (strcmp(id, iterator->id) != 0))
	iterator = iterator->next;
	if (iterator != NULL) {
	/*
	* 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 == NULL)
	iterator = NULL;
	else {
	engine_cpy(cp, iterator);
	iterator = cp;
	}
	} else {
	iterator->struct_ref++;
	ENGINE_REF_PRINT(iterator, 0, 1);
	}
	}
	CRYPTO_THREAD_unlock(global_engine_lock);
	if (iterator != NULL)
	return iterator;
	/*
	* Prevent infinite recursion if we're looking for the dynamic engine.
	*/
	if (strcmp(id, "dynamic")) {
	if ((load_dir = ossl_safe_getenv("OPENSSL_ENGINES")) == NULL)
	load_dir = ENGINESDIR;
	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);
	ERR_raise_data(ERR_LIB_ENGINE, ENGINE_R_NO_SUCH_ENGINE, "id=%s", id);
	return NULL;
	/* EEK! Experimental code ends */
	}

	int ENGINE_up_ref(ENGINE *e)
	{
	int i;
	if (e == NULL) {
	ERR_raise(ERR_LIB_ENGINE, ERR_R_PASSED_NULL_PARAMETER);
	return 0;
	}
	CRYPTO_UP_REF(&e->struct_ref, &i, global_engine_lock);
	return 1;
	}