Depend on OPENSSL_NO_STATIC_ENGINE rather than OPENSSL_NO_DYNAMIC_ENGINE.

[openssl.git] / crypto / engine / engine.h

/* openssl/engine.h */
/* 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.
 */

#ifndef HEADER_ENGINE_H
#define HEADER_ENGINE_H

#include <openssl/opensslconf.h>
#include <openssl/ossl_typ.h>
#include <openssl/bn.h>
#ifndef OPENSSL_NO_RSA
#include <openssl/rsa.h>
#endif
#ifndef OPENSSL_NO_DSA
#include <openssl/dsa.h>
#endif
#ifndef OPENSSL_NO_DH
#include <openssl/dh.h>
#endif
#ifndef OPENSSL_NO_ECDH
#include <openssl/ecdh.h>
#endif
#ifndef OPENSSL_NO_ECDSA
#include <openssl/ecdsa.h>
#endif
#include <openssl/rand.h>
#include <openssl/ui.h>
#include <openssl/symhacks.h>
#include <openssl/err.h>

#ifdef  __cplusplus
extern "C" {
#endif

/* Fixups for missing algorithms */
#ifdef OPENSSL_NO_RSA
typedef void RSA_METHOD;
#endif
#ifdef OPENSSL_NO_DSA
typedef void DSA_METHOD;
#endif
#ifdef OPENSSL_NO_DH
typedef void DH_METHOD;
#endif
#ifdef OPENSSL_NO_ECDH
typedef void ECDH_METHOD;
#endif
#ifdef OPENSSL_NO_ECDSA
typedef void ECDSA_METHOD;
#endif

/* These flags are used to control combinations of algorithm (methods)
 * by bitwise "OR"ing. */
#define ENGINE_METHOD_RSA               (unsigned int)0x0001
#define ENGINE_METHOD_DSA               (unsigned int)0x0002
#define ENGINE_METHOD_DH                (unsigned int)0x0004
#define ENGINE_METHOD_RAND              (unsigned int)0x0008
#define ENGINE_METHOD_ECDH              (unsigned int)0x0010
#define ENGINE_METHOD_ECDSA             (unsigned int)0x0020
#define ENGINE_METHOD_CIPHERS           (unsigned int)0x0040
#define ENGINE_METHOD_DIGESTS           (unsigned int)0x0080
/* Obvious all-or-nothing cases. */
#define ENGINE_METHOD_ALL               (unsigned int)0xFFFF
#define ENGINE_METHOD_NONE              (unsigned int)0x0000

/* This(ese) flag(s) controls behaviour of the ENGINE_TABLE mechanism used
 * internally to control registration of ENGINE implementations, and can be set
 * by ENGINE_set_table_flags(). The "NOINIT" flag prevents attempts to
 * initialise registered ENGINEs if they are not already initialised. */
#define ENGINE_TABLE_FLAG_NOINIT        (unsigned int)0x0001

/* ENGINE flags that can be set by ENGINE_set_flags(). */
/* #define ENGINE_FLAGS_MALLOCED        0x0001 */ /* Not used */

/* This flag is for ENGINEs that wish to handle the various 'CMD'-related
 * control commands on their own. Without this flag, ENGINE_ctrl() handles these
 * control commands on behalf of the ENGINE using their "cmd_defns" data. */
#define ENGINE_FLAGS_MANUAL_CMD_CTRL    (int)0x0002

/* This flag is for ENGINEs who return new duplicate structures when found via
 * "ENGINE_by_id()". When an ENGINE must store state (eg. if ENGINE_ctrl()
 * commands are called in sequence as part of some stateful process like
 * key-generation setup and execution), it can set this flag - then each attempt
 * to obtain the ENGINE will result in it being copied into a new structure.
 * Normally, ENGINEs don't declare this flag so ENGINE_by_id() just increments
 * the existing ENGINE's structural reference count. */
#define ENGINE_FLAGS_BY_ID_COPY         (int)0x0004

/* ENGINEs can support their own command types, and these flags are used in
 * ENGINE_CTRL_GET_CMD_FLAGS to indicate to the caller what kind of input each
 * command expects. Currently only numeric and string input is supported. If a
 * control command supports none of the _NUMERIC, _STRING, or _NO_INPUT options,
 * then it is regarded as an "internal" control command - and not for use in
 * config setting situations. As such, they're not available to the
 * ENGINE_ctrl_cmd_string() function, only raw ENGINE_ctrl() access. Changes to
 * this list of 'command types' should be reflected carefully in
 * ENGINE_cmd_is_executable() and ENGINE_ctrl_cmd_string(). */

/* accepts a 'long' input value (3rd parameter to ENGINE_ctrl) */
#define ENGINE_CMD_FLAG_NUMERIC         (unsigned int)0x0001
/* accepts string input (cast from 'void*' to 'const char *', 4th parameter to
 * ENGINE_ctrl) */
#define ENGINE_CMD_FLAG_STRING          (unsigned int)0x0002
/* Indicates that the control command takes *no* input. Ie. the control command
 * is unparameterised. */
#define ENGINE_CMD_FLAG_NO_INPUT        (unsigned int)0x0004
/* Indicates that the control command is internal. This control command won't
 * be shown in any output, and is only usable through the ENGINE_ctrl_cmd()
 * function. */
#define ENGINE_CMD_FLAG_INTERNAL        (unsigned int)0x0008

/* NB: These 3 control commands are deprecated and should not be used. ENGINEs
 * relying on these commands should compile conditional support for
 * compatibility (eg. if these symbols are defined) but should also migrate the
 * same functionality to their own ENGINE-specific control functions that can be
 * "discovered" by calling applications. The fact these control commands
 * wouldn't be "executable" (ie. usable by text-based config) doesn't change the
 * fact that application code can find and use them without requiring per-ENGINE
 * hacking. */

/* These flags are used to tell the ctrl function what should be done.
 * All command numbers are shared between all engines, even if some don't
 * make sense to some engines.  In such a case, they do nothing but return
 * the error ENGINE_R_CTRL_COMMAND_NOT_IMPLEMENTED. */
#define ENGINE_CTRL_SET_LOGSTREAM               1
#define ENGINE_CTRL_SET_PASSWORD_CALLBACK       2
#define ENGINE_CTRL_HUP                         3 /* Close and reinitialise any
                                                     handles/connections etc. */
#define ENGINE_CTRL_SET_USER_INTERFACE          4 /* Alternative to callback */
#define ENGINE_CTRL_SET_CALLBACK_DATA           5 /* User-specific data, used
                                                     when calling the password
                                                     callback and the user
                                                     interface */

/* These control commands allow an application to deal with an arbitrary engine
 * in a dynamic way. Warn: Negative return values indicate errors FOR THESE
 * COMMANDS because zero is used to indicate 'end-of-list'. Other commands,
 * including ENGINE-specific command types, return zero for an error.
 *
 * An ENGINE can choose to implement these ctrl functions, and can internally
 * manage things however it chooses - it does so by setting the
 * ENGINE_FLAGS_MANUAL_CMD_CTRL flag (using ENGINE_set_flags()). Otherwise the
 * ENGINE_ctrl() code handles this on the ENGINE's behalf using the cmd_defns
 * data (set using ENGINE_set_cmd_defns()). This means an ENGINE's ctrl()
 * handler need only implement its own commands - the above "meta" commands will
 * be taken care of. */

/* Returns non-zero if the supplied ENGINE has a ctrl() handler. If "not", then
 * all the remaining control commands will return failure, so it is worth
 * checking this first if the caller is trying to "discover" the engine's
 * capabilities and doesn't want errors generated unnecessarily. */
#define ENGINE_CTRL_HAS_CTRL_FUNCTION           10
/* Returns a positive command number for the first command supported by the
 * engine. Returns zero if no ctrl commands are supported. */
#define ENGINE_CTRL_GET_FIRST_CMD_TYPE          11
/* The 'long' argument specifies a command implemented by the engine, and the
 * return value is the next command supported, or zero if there are no more. */
#define ENGINE_CTRL_GET_NEXT_CMD_TYPE           12
/* The 'void*' argument is a command name (cast from 'const char *'), and the
 * return value is the command that corresponds to it. */
#define ENGINE_CTRL_GET_CMD_FROM_NAME           13
/* The next two allow a command to be converted into its corresponding string
 * form. In each case, the 'long' argument supplies the command. In the NAME_LEN
 * case, the return value is the length of the command name (not counting a
 * trailing EOL). In the NAME case, the 'void*' argument must be a string buffer
 * large enough, and it will be populated with the name of the command (WITH a
 * trailing EOL). */
#define ENGINE_CTRL_GET_NAME_LEN_FROM_CMD       14
#define ENGINE_CTRL_GET_NAME_FROM_CMD           15
/* The next two are similar but give a "short description" of a command. */
#define ENGINE_CTRL_GET_DESC_LEN_FROM_CMD       16
#define ENGINE_CTRL_GET_DESC_FROM_CMD           17
/* With this command, the return value is the OR'd combination of
 * ENGINE_CMD_FLAG_*** values that indicate what kind of input a given
 * engine-specific ctrl command expects. */
#define ENGINE_CTRL_GET_CMD_FLAGS               18

/* ENGINE implementations should start the numbering of their own control
 * commands from this value. (ie. ENGINE_CMD_BASE, ENGINE_CMD_BASE + 1, etc). */
#define ENGINE_CMD_BASE         200

/* NB: These 2 nCipher "chil" control commands are deprecated, and their
 * functionality is now available through ENGINE-specific control commands
 * (exposed through the above-mentioned 'CMD'-handling). Code using these 2
 * commands should be migrated to the more general command handling before these
 * are removed. */

/* Flags specific to the nCipher "chil" engine */
#define ENGINE_CTRL_CHIL_SET_FORKCHECK          100
        /* Depending on the value of the (long)i argument, this sets or
         * unsets the SimpleForkCheck flag in the CHIL API to enable or
         * disable checking and workarounds for applications that fork().
         */
#define ENGINE_CTRL_CHIL_NO_LOCKING             101
        /* This prevents the initialisation function from providing mutex
         * callbacks to the nCipher library. */

/* If an ENGINE supports its own specific control commands and wishes the
 * framework to handle the above 'ENGINE_CMD_***'-manipulation commands on its
 * behalf, it should supply a null-terminated array of ENGINE_CMD_DEFN entries
 * to ENGINE_set_cmd_defns(). It should also implement a ctrl() handler that
 * supports the stated commands (ie. the "cmd_num" entries as described by the
 * array). NB: The array must be ordered in increasing order of cmd_num.
 * "null-terminated" means that the last ENGINE_CMD_DEFN element has cmd_num set
 * to zero and/or cmd_name set to NULL. */
typedef struct ENGINE_CMD_DEFN_st
        {
        unsigned int cmd_num; /* The command number */
        const char *cmd_name; /* The command name itself */
        const char *cmd_desc; /* A short description of the command */
        unsigned int cmd_flags; /* The input the command expects */
        } ENGINE_CMD_DEFN;

/* Generic function pointer */
typedef int (*ENGINE_GEN_FUNC_PTR)();
/* Generic function pointer taking no arguments */
typedef int (*ENGINE_GEN_INT_FUNC_PTR)(ENGINE *);
/* Specific control function pointer */
typedef int (*ENGINE_CTRL_FUNC_PTR)(ENGINE *, int, long, void *, void (*f)());
/* Generic load_key function pointer */
typedef EVP_PKEY * (*ENGINE_LOAD_KEY_PTR)(ENGINE *, const char *,
        UI_METHOD *ui_method, void *callback_data);
/* These callback types are for an ENGINE's handler for cipher and digest logic.
 * These handlers have these prototypes;
 *   int foo(ENGINE *e, const EVP_CIPHER **cipher, const int **nids, int nid);
 *   int foo(ENGINE *e, const EVP_MD **digest, const int **nids, int nid);
 * Looking at how to implement these handlers in the case of cipher support, if
 * the framework wants the EVP_CIPHER for 'nid', it will call;
 *   foo(e, &p_evp_cipher, NULL, nid);    (return zero for failure)
 * If the framework wants a list of supported 'nid's, it will call;
 *   foo(e, NULL, &p_nids, 0); (returns number of 'nids' or -1 for error)
 */
/* Returns to a pointer to the array of supported cipher 'nid's. If the second
 * parameter is non-NULL it is set to the size of the returned array. */
typedef int (*ENGINE_CIPHERS_PTR)(ENGINE *, const EVP_CIPHER **, const int **, int);
typedef int (*ENGINE_DIGESTS_PTR)(ENGINE *, const EVP_MD **, const int **, int);

/* STRUCTURE functions ... all of these functions deal with pointers to ENGINE
 * structures where the pointers have a "structural reference". This means that
 * their reference is to allowed access to the structure but it does not imply
 * that the structure is functional. To simply increment or decrement the
 * structural reference count, use ENGINE_by_id and ENGINE_free. NB: This is not
 * required when iterating using ENGINE_get_next as it will automatically
 * decrement the structural reference count of the "current" ENGINE and
 * increment the structural reference count of the ENGINE it returns (unless it
 * is NULL). */

/* Get the first/last "ENGINE" type available. */
ENGINE *ENGINE_get_first(void);
ENGINE *ENGINE_get_last(void);
/* Iterate to the next/previous "ENGINE" type (NULL = end of the list). */
ENGINE *ENGINE_get_next(ENGINE *e);
ENGINE *ENGINE_get_prev(ENGINE *e);
/* Add another "ENGINE" type into the array. */
int ENGINE_add(ENGINE *e);
/* Remove an existing "ENGINE" type from the array. */
int ENGINE_remove(ENGINE *e);
/* Retrieve an engine from the list by its unique "id" value. */
ENGINE *ENGINE_by_id(const char *id);
/* Add all the built-in engines. */
void ENGINE_load_openssl(void);
void ENGINE_load_dynamic(void);
#ifndef OPENSSL_NO_STATIC_ENGINE
void ENGINE_load_cswift(void);
void ENGINE_load_chil(void);
void ENGINE_load_atalla(void);
void ENGINE_load_nuron(void);
void ENGINE_load_ubsec(void);
void ENGINE_load_aep(void);
void ENGINE_load_sureware(void);
void ENGINE_load_4758cca(void);
#endif
void ENGINE_load_cryptodev(void);
void ENGINE_load_builtin_engines(void);

/* Get and set global flags (ENGINE_TABLE_FLAG_***) for the implementation
 * "registry" handling. */
unsigned int ENGINE_get_table_flags(void);
void ENGINE_set_table_flags(unsigned int flags);

/* Manage registration of ENGINEs per "table". For each type, there are 3
 * functions;
 *   ENGINE_register_***(e) - registers the implementation from 'e' (if it has one)
 *   ENGINE_unregister_***(e) - unregister the implementation from 'e'
 *   ENGINE_register_all_***() - call ENGINE_register_***() for each 'e' in the list
 * Cleanup is automatically registered from each table when required, so
 * ENGINE_cleanup() will reverse any "register" operations. */

int ENGINE_register_RSA(ENGINE *e);
void ENGINE_unregister_RSA(ENGINE *e);
void ENGINE_register_all_RSA(void);

int ENGINE_register_DSA(ENGINE *e);
void ENGINE_unregister_DSA(ENGINE *e);
void ENGINE_register_all_DSA(void);

int ENGINE_register_ECDH(ENGINE *e);
void ENGINE_unregister_ECDH(ENGINE *e);
void ENGINE_register_all_ECDH(void);

int ENGINE_register_ECDSA(ENGINE *e);
void ENGINE_unregister_ECDSA(ENGINE *e);
void ENGINE_register_all_ECDSA(void);

int ENGINE_register_DH(ENGINE *e);
void ENGINE_unregister_DH(ENGINE *e);
void ENGINE_register_all_DH(void);

int ENGINE_register_RAND(ENGINE *e);
void ENGINE_unregister_RAND(ENGINE *e);
void ENGINE_register_all_RAND(void);

int ENGINE_register_ciphers(ENGINE *e);
void ENGINE_unregister_ciphers(ENGINE *e);
void ENGINE_register_all_ciphers(void);

int ENGINE_register_digests(ENGINE *e);
void ENGINE_unregister_digests(ENGINE *e);
void ENGINE_register_all_digests(void);

/* These functions register all support from the above categories. Note, use of
 * these functions can result in static linkage of code your application may not
 * need. If you only need a subset of functionality, consider using more
 * selective initialisation. */
int ENGINE_register_complete(ENGINE *e);
int ENGINE_register_all_complete(void);

/* Send parametrised control commands to the engine. The possibilities to send
 * down an integer, a pointer to data or a function pointer are provided. Any of
 * the parameters may or may not be NULL, depending on the command number. In
 * actuality, this function only requires a structural (rather than functional)
 * reference to an engine, but many control commands may require the engine be
 * functional. The caller should be aware of trying commands that require an
 * operational ENGINE, and only use functional references in such situations. */
int ENGINE_ctrl(ENGINE *e, int cmd, long i, void *p, void (*f)());

/* This function tests if an ENGINE-specific command is usable as a "setting".
 * Eg. in an application's config file that gets processed through
 * ENGINE_ctrl_cmd_string(). If this returns zero, it is not available to
 * ENGINE_ctrl_cmd_string(), only ENGINE_ctrl(). */
int ENGINE_cmd_is_executable(ENGINE *e, int cmd);

/* This function works like ENGINE_ctrl() with the exception of taking a
 * command name instead of a command number, and can handle optional commands.
 * See the comment on ENGINE_ctrl_cmd_string() for an explanation on how to
 * use the cmd_name and cmd_optional. */
int ENGINE_ctrl_cmd(ENGINE *e, const char *cmd_name,
        long i, void *p, void (*f)(), int cmd_optional);

/* This function passes a command-name and argument to an ENGINE. The cmd_name
 * is converted to a command number and the control command is called using
 * 'arg' as an argument (unless the ENGINE doesn't support such a command, in
 * which case no control command is called). The command is checked for input
 * flags, and if necessary the argument will be converted to a numeric value. If
 * cmd_optional is non-zero, then if the ENGINE doesn't support the given
 * cmd_name the return value will be success anyway. This function is intended
 * for applications to use so that users (or config files) can supply
 * engine-specific config data to the ENGINE at run-time to control behaviour of
 * specific engines. As such, it shouldn't be used for calling ENGINE_ctrl()
 * functions that return data, deal with binary data, or that are otherwise
 * supposed to be used directly through ENGINE_ctrl() in application code. Any
 * "return" data from an ENGINE_ctrl() operation in this function will be lost -
 * the return value is interpreted as failure if the return value is zero,
 * success otherwise, and this function returns a boolean value as a result. In
 * other words, vendors of 'ENGINE'-enabled devices should write ENGINE
 * implementations with parameterisations that work in this scheme, so that
 * compliant ENGINE-based applications can work consistently with the same
 * configuration for the same ENGINE-enabled devices, across applications. */
int ENGINE_ctrl_cmd_string(ENGINE *e, const char *cmd_name, const char *arg,
                                int cmd_optional);

/* These functions are useful for manufacturing new ENGINE structures. They
 * don't address reference counting at all - one uses them to populate an ENGINE
 * structure with personalised implementations of things prior to using it
 * directly or adding it to the builtin ENGINE list in OpenSSL. These are also
 * here so that the ENGINE structure doesn't have to be exposed and break binary
 * compatibility! */
ENGINE *ENGINE_new(void);
int ENGINE_free(ENGINE *e);
int ENGINE_up_ref(ENGINE *e);
int ENGINE_set_id(ENGINE *e, const char *id);
int ENGINE_set_name(ENGINE *e, const char *name);
int ENGINE_set_RSA(ENGINE *e, const RSA_METHOD *rsa_meth);
int ENGINE_set_DSA(ENGINE *e, const DSA_METHOD *dsa_meth);
int ENGINE_set_ECDH(ENGINE *e, const ECDH_METHOD *ecdh_meth);
int ENGINE_set_ECDSA(ENGINE *e, const ECDSA_METHOD *ecdsa_meth);
int ENGINE_set_DH(ENGINE *e, const DH_METHOD *dh_meth);
int ENGINE_set_RAND(ENGINE *e, const RAND_METHOD *rand_meth);
int ENGINE_set_destroy_function(ENGINE *e, ENGINE_GEN_INT_FUNC_PTR destroy_f);
int ENGINE_set_init_function(ENGINE *e, ENGINE_GEN_INT_FUNC_PTR init_f);
int ENGINE_set_finish_function(ENGINE *e, ENGINE_GEN_INT_FUNC_PTR finish_f);
int ENGINE_set_ctrl_function(ENGINE *e, ENGINE_CTRL_FUNC_PTR ctrl_f);
int ENGINE_set_load_privkey_function(ENGINE *e, ENGINE_LOAD_KEY_PTR loadpriv_f);
int ENGINE_set_load_pubkey_function(ENGINE *e, ENGINE_LOAD_KEY_PTR loadpub_f);
int ENGINE_set_ciphers(ENGINE *e, ENGINE_CIPHERS_PTR f);
int ENGINE_set_digests(ENGINE *e, ENGINE_DIGESTS_PTR f);
int ENGINE_set_flags(ENGINE *e, int flags);
int ENGINE_set_cmd_defns(ENGINE *e, const ENGINE_CMD_DEFN *defns);
/* These functions (and the "get" function lower down) allow control over any
 * per-structure ENGINE data. */
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);
int ENGINE_set_ex_data(ENGINE *e, int idx, void *arg);

/* This function cleans up anything that needs it. Eg. the ENGINE_add() function
 * automatically ensures the list cleanup function is registered to be called
 * from ENGINE_cleanup(). Similarly, all ENGINE_register_*** functions ensure
 * ENGINE_cleanup() will clean up after them. */
void ENGINE_cleanup(void);

/* These return values from within the ENGINE structure. These can be useful
 * with functional references as well as structural references - it depends
 * which you obtained. Using the result for functional purposes if you only
 * obtained a structural reference may be problematic! */
const char *ENGINE_get_id(const ENGINE *e);
const char *ENGINE_get_name(const ENGINE *e);
const RSA_METHOD *ENGINE_get_RSA(const ENGINE *e);
const DSA_METHOD *ENGINE_get_DSA(const ENGINE *e);
const ECDH_METHOD *ENGINE_get_ECDH(const ENGINE *e);
const ECDSA_METHOD *ENGINE_get_ECDSA(const ENGINE *e);
const DH_METHOD *ENGINE_get_DH(const ENGINE *e);
const RAND_METHOD *ENGINE_get_RAND(const ENGINE *e);
ENGINE_GEN_INT_FUNC_PTR ENGINE_get_destroy_function(const ENGINE *e);
ENGINE_GEN_INT_FUNC_PTR ENGINE_get_init_function(const ENGINE *e);
ENGINE_GEN_INT_FUNC_PTR ENGINE_get_finish_function(const ENGINE *e);
ENGINE_CTRL_FUNC_PTR ENGINE_get_ctrl_function(const ENGINE *e);
ENGINE_LOAD_KEY_PTR ENGINE_get_load_privkey_function(const ENGINE *e);
ENGINE_LOAD_KEY_PTR ENGINE_get_load_pubkey_function(const ENGINE *e);
ENGINE_CIPHERS_PTR ENGINE_get_ciphers(const ENGINE *e);
ENGINE_DIGESTS_PTR ENGINE_get_digests(const ENGINE *e);
const EVP_CIPHER *ENGINE_get_cipher(ENGINE *e, int nid);
const EVP_MD *ENGINE_get_digest(ENGINE *e, int nid);
const ENGINE_CMD_DEFN *ENGINE_get_cmd_defns(const ENGINE *e);
int ENGINE_get_flags(const ENGINE *e);
void *ENGINE_get_ex_data(const ENGINE *e, int idx);

/* FUNCTIONAL functions. These functions deal with ENGINE structures
 * that have (or will) be initialised for use. Broadly speaking, the
 * structural functions are useful for iterating the list of available
 * engine types, creating new engine types, and other "list" operations.
 * These functions actually deal with ENGINEs that are to be used. As
 * such these functions can fail (if applicable) when particular
 * engines are unavailable - eg. if a hardware accelerator is not
 * attached or not functioning correctly. Each ENGINE has 2 reference
 * counts; structural and functional. Every time a functional reference
 * is obtained or released, a corresponding structural reference is
 * automatically obtained or released too. */

/* Initialise a engine type for use (or up its reference count if it's
 * already in use). This will fail if the engine is not currently
 * operational and cannot initialise. */
int ENGINE_init(ENGINE *e);
/* Free a functional reference to a engine type. This does not require
 * a corresponding call to ENGINE_free as it also releases a structural
 * reference. */
int ENGINE_finish(ENGINE *e);

/* The following functions handle keys that are stored in some secondary
 * location, handled by the engine.  The storage may be on a card or
 * whatever. */
EVP_PKEY *ENGINE_load_private_key(ENGINE *e, const char *key_id,
        UI_METHOD *ui_method, void *callback_data);
EVP_PKEY *ENGINE_load_public_key(ENGINE *e, const char *key_id,
        UI_METHOD *ui_method, void *callback_data);

/* This returns a pointer for the current ENGINE structure that
 * is (by default) performing any RSA operations. The value returned
 * is an incremented reference, so it should be free'd (ENGINE_finish)
 * before it is discarded. */
ENGINE *ENGINE_get_default_RSA(void);
/* Same for the other "methods" */
ENGINE *ENGINE_get_default_DSA(void);
ENGINE *ENGINE_get_default_ECDH(void);
ENGINE *ENGINE_get_default_ECDSA(void);
ENGINE *ENGINE_get_default_DH(void);
ENGINE *ENGINE_get_default_RAND(void);
/* These functions can be used to get a functional reference to perform
 * ciphering or digesting corresponding to "nid". */
ENGINE *ENGINE_get_cipher_engine(int nid);
ENGINE *ENGINE_get_digest_engine(int nid);

/* This sets a new default ENGINE structure for performing RSA
 * operations. If the result is non-zero (success) then the ENGINE
 * structure will have had its reference count up'd so the caller
 * should still free their own reference 'e'. */
int ENGINE_set_default_RSA(ENGINE *e);
int ENGINE_set_default_string(ENGINE *e, const char *list);
/* Same for the other "methods" */
int ENGINE_set_default_DSA(ENGINE *e);
int ENGINE_set_default_ECDH(ENGINE *e);
int ENGINE_set_default_ECDSA(ENGINE *e);
int ENGINE_set_default_DH(ENGINE *e);
int ENGINE_set_default_RAND(ENGINE *e);
int ENGINE_set_default_ciphers(ENGINE *e);
int ENGINE_set_default_digests(ENGINE *e);

/* The combination "set" - the flags are bitwise "OR"d from the
 * ENGINE_METHOD_*** defines above. As with the "ENGINE_register_complete()"
 * function, this function can result in unnecessary static linkage. If your
 * application requires only specific functionality, consider using more
 * selective functions. */
int ENGINE_set_default(ENGINE *e, unsigned int flags);

void ENGINE_add_conf_module(void);

/* Deprecated functions ... */
/* int ENGINE_clear_defaults(void); */

/**************************/
/* DYNAMIC ENGINE SUPPORT */
/**************************/

/* Binary/behaviour compatibility levels */
#define OSSL_DYNAMIC_VERSION            (unsigned long)0x00010200
/* Binary versions older than this are too old for us (whether we're a loader or
 * a loadee) */
#define OSSL_DYNAMIC_OLDEST             (unsigned long)0x00010200

/* When compiling an ENGINE entirely as an external shared library, loadable by
 * the "dynamic" ENGINE, these types are needed. The 'dynamic_fns' structure
 * type provides the calling application's (or library's) error functionality
 * and memory management function pointers to the loaded library. These should
 * be used/set in the loaded library code so that the loading application's
 * 'state' will be used/changed in all operations. The 'static_state' pointer
 * allows the loaded library to know if it shares the same static data as the
 * calling application (or library), and thus whether these callbacks need to be
 * set or not. */
typedef void *(*dyn_MEM_malloc_cb)(size_t);
typedef void *(*dyn_MEM_realloc_cb)(void *, size_t);
typedef void (*dyn_MEM_free_cb)(void *);
typedef struct st_dynamic_MEM_fns {
        dyn_MEM_malloc_cb                       malloc_cb;
        dyn_MEM_realloc_cb                      realloc_cb;
        dyn_MEM_free_cb                         free_cb;
        } dynamic_MEM_fns;
/* FIXME: Perhaps the memory and locking code (crypto.h) should declare and use
 * these types so we (and any other dependant code) can simplify a bit?? */
typedef void (*dyn_lock_locking_cb)(int,int,const char *,int);
typedef int (*dyn_lock_add_lock_cb)(int*,int,int,const char *,int);
typedef struct CRYPTO_dynlock_value *(*dyn_dynlock_create_cb)(
                                                const char *,int);
typedef void (*dyn_dynlock_lock_cb)(int,struct CRYPTO_dynlock_value *,
                                                const char *,int);
typedef void (*dyn_dynlock_destroy_cb)(struct CRYPTO_dynlock_value *,
                                                const char *,int);
typedef struct st_dynamic_LOCK_fns {
        dyn_lock_locking_cb                     lock_locking_cb;
        dyn_lock_add_lock_cb                    lock_add_lock_cb;
        dyn_dynlock_create_cb                   dynlock_create_cb;
        dyn_dynlock_lock_cb                     dynlock_lock_cb;
        dyn_dynlock_destroy_cb                  dynlock_destroy_cb;
        } dynamic_LOCK_fns;
/* The top-level structure */
typedef struct st_dynamic_fns {
        void                                    *static_state;
        const ERR_FNS                           *err_fns;
        const CRYPTO_EX_DATA_IMPL               *ex_data_fns;
        dynamic_MEM_fns                         mem_fns;
        dynamic_LOCK_fns                        lock_fns;
        } dynamic_fns;

/* The version checking function should be of this prototype. NB: The
 * ossl_version value passed in is the OSSL_DYNAMIC_VERSION of the loading code.
 * If this function returns zero, it indicates a (potential) version
 * incompatibility and the loaded library doesn't believe it can proceed.
 * Otherwise, the returned value is the (latest) version supported by the
 * loading library. The loader may still decide that the loaded code's version
 * is unsatisfactory and could veto the load. The function is expected to
 * be implemented with the symbol name "v_check", and a default implementation
 * can be fully instantiated with IMPLEMENT_DYNAMIC_CHECK_FN(). */
typedef unsigned long (*dynamic_v_check_fn)(unsigned long ossl_version);
#define IMPLEMENT_DYNAMIC_CHECK_FN() \
        unsigned long v_check(unsigned long v) { \
                if(v >= OSSL_DYNAMIC_OLDEST) return OSSL_DYNAMIC_VERSION; \
                return 0; }

/* This function is passed the ENGINE structure to initialise with its own
 * function and command settings. It should not adjust the structural or
 * functional reference counts. If this function returns zero, (a) the load will
 * be aborted, (b) the previous ENGINE state will be memcpy'd back onto the
 * structure, and (c) the shared library will be unloaded. So implementations
 * should do their own internal cleanup in failure circumstances otherwise they
 * could leak. The 'id' parameter, if non-NULL, represents the ENGINE id that
 * the loader is looking for. If this is NULL, the shared library can choose to
 * return failure or to initialise a 'default' ENGINE. If non-NULL, the shared
 * library must initialise only an ENGINE matching the passed 'id'. The function
 * is expected to be implemented with the symbol name "bind_engine". A standard
 * implementation can be instantiated with IMPLEMENT_DYNAMIC_BIND_FN(fn) where
 * the parameter 'fn' is a callback function that populates the ENGINE structure
 * and returns an int value (zero for failure). 'fn' should have prototype;
 *    [static] int fn(ENGINE *e, const char *id); */
typedef int (*dynamic_bind_engine)(ENGINE *e, const char *id,
                                const dynamic_fns *fns);
#define IMPLEMENT_DYNAMIC_BIND_FN(fn) \
        int bind_engine(ENGINE *e, const char *id, const dynamic_fns *fns) { \
                if(ENGINE_get_static_state() == fns->static_state) goto skip_cbs; \
                if(!CRYPTO_set_mem_functions(fns->mem_fns.malloc_cb, \
                        fns->mem_fns.realloc_cb, fns->mem_fns.free_cb)) \
                        return 0; \
                CRYPTO_set_locking_callback(fns->lock_fns.lock_locking_cb); \
                CRYPTO_set_add_lock_callback(fns->lock_fns.lock_add_lock_cb); \
                CRYPTO_set_dynlock_create_callback(fns->lock_fns.dynlock_create_cb); \
                CRYPTO_set_dynlock_lock_callback(fns->lock_fns.dynlock_lock_cb); \
                CRYPTO_set_dynlock_destroy_callback(fns->lock_fns.dynlock_destroy_cb); \
                if(!CRYPTO_set_ex_data_implementation(fns->ex_data_fns)) \
                        return 0; \
                if(!ERR_set_implementation(fns->err_fns)) return 0; \
        skip_cbs: \
                if(!fn(e,id)) return 0; \
                return 1; }

/* If the loading application (or library) and the loaded ENGINE library share
 * the same static data (eg. they're both dynamically linked to the same
 * libcrypto.so) we need a way to avoid trying to set system callbacks - this
 * would fail, and for the same reason that it's unnecessary to try. If the
 * loaded ENGINE has (or gets from through the loader) its own copy of the
 * libcrypto static data, we will need to set the callbacks. The easiest way to
 * detect this is to have a function that returns a pointer to some static data
 * and let the loading application and loaded ENGINE compare their respective
 * values. */
void *ENGINE_get_static_state(void);


/* BEGIN ERROR CODES */
/* The following lines are auto generated by the script mkerr.pl. Any changes
 * made after this point may be overwritten when the script is next run.
 */
void ERR_load_ENGINE_strings(void);

/* Error codes for the ENGINE functions. */

/* Function codes. */
#define ENGINE_F_DYNAMIC_CTRL                            180
#define ENGINE_F_DYNAMIC_GET_DATA_CTX                    181
#define ENGINE_F_DYNAMIC_LOAD                            182
#define ENGINE_F_ENGINE_ADD                              105
#define ENGINE_F_ENGINE_BY_ID                            106
#define ENGINE_F_ENGINE_CMD_IS_EXECUTABLE                170
#define ENGINE_F_ENGINE_CTRL                             142
#define ENGINE_F_ENGINE_CTRL_CMD                         178
#define ENGINE_F_ENGINE_CTRL_CMD_STRING                  171
#define ENGINE_F_ENGINE_FINISH                           107
#define ENGINE_F_ENGINE_FREE                             108
#define ENGINE_F_ENGINE_GET_CIPHER                       185
#define ENGINE_F_ENGINE_GET_DEFAULT_TYPE                 177
#define ENGINE_F_ENGINE_GET_DIGEST                       186
#define ENGINE_F_ENGINE_GET_NEXT                         115
#define ENGINE_F_ENGINE_GET_PREV                         116
#define ENGINE_F_ENGINE_INIT                             119
#define ENGINE_F_ENGINE_LIST_ADD                         120
#define ENGINE_F_ENGINE_LIST_REMOVE                      121
#define ENGINE_F_ENGINE_LOAD_PRIVATE_KEY                 150
#define ENGINE_F_ENGINE_LOAD_PUBLIC_KEY                  151
#define ENGINE_F_ENGINE_MODULE_INIT                      187
#define ENGINE_F_ENGINE_NEW                              122
#define ENGINE_F_ENGINE_REMOVE                           123
#define ENGINE_F_ENGINE_SET_DEFAULT_STRING               189
#define ENGINE_F_ENGINE_SET_DEFAULT_TYPE                 126
#define ENGINE_F_ENGINE_SET_ID                           129
#define ENGINE_F_ENGINE_SET_NAME                         130
#define ENGINE_F_ENGINE_TABLE_REGISTER                   184
#define ENGINE_F_ENGINE_UNLOAD_KEY                       152
#define ENGINE_F_ENGINE_UP_REF                           190
#define ENGINE_F_INT_CTRL_HELPER                         172
#define ENGINE_F_INT_ENGINE_CONFIGURE                    188
#define ENGINE_F_LOG_MESSAGE                             141
#define ENGINE_F_SET_DATA_CTX                            183

/* Reason codes. */
#define ENGINE_R_ALREADY_LOADED                          100
#define ENGINE_R_ARGUMENT_IS_NOT_A_NUMBER                133
#define ENGINE_R_CMD_NOT_EXECUTABLE                      134
#define ENGINE_R_COMMAND_TAKES_INPUT                     135
#define ENGINE_R_COMMAND_TAKES_NO_INPUT                  136
#define ENGINE_R_CONFLICTING_ENGINE_ID                   103
#define ENGINE_R_CTRL_COMMAND_NOT_IMPLEMENTED            119
#define ENGINE_R_DH_NOT_IMPLEMENTED                      139
#define ENGINE_R_DSA_NOT_IMPLEMENTED                     140
#define ENGINE_R_DSO_FAILURE                             104
#define ENGINE_R_DSO_NOT_FOUND                           132
#define ENGINE_R_ENGINES_SECTION_ERROR                   148
#define ENGINE_R_ENGINE_IS_NOT_IN_LIST                   105
#define ENGINE_R_ENGINE_SECTION_ERROR                    149
#define ENGINE_R_FAILED_LOADING_PRIVATE_KEY              128
#define ENGINE_R_FAILED_LOADING_PUBLIC_KEY               129
#define ENGINE_R_FINISH_FAILED                           106
#define ENGINE_R_GET_HANDLE_FAILED                       107
#define ENGINE_R_ID_OR_NAME_MISSING                      108
#define ENGINE_R_INIT_FAILED                             109
#define ENGINE_R_INTERNAL_LIST_ERROR                     110
#define ENGINE_R_INVALID_ARGUMENT                        143
#define ENGINE_R_INVALID_CMD_NAME                        137
#define ENGINE_R_INVALID_CMD_NUMBER                      138
#define ENGINE_R_INVALID_INIT_VALUE                      151
#define ENGINE_R_INVALID_STRING                          150
#define ENGINE_R_NOT_INITIALISED                         117
#define ENGINE_R_NOT_LOADED                              112
#define ENGINE_R_NO_CONTROL_FUNCTION                     120
#define ENGINE_R_NO_INDEX                                144
#define ENGINE_R_NO_LOAD_FUNCTION                        125
#define ENGINE_R_NO_REFERENCE                            130
#define ENGINE_R_NO_SUCH_ENGINE                          116
#define ENGINE_R_NO_UNLOAD_FUNCTION                      126
#define ENGINE_R_PROVIDE_PARAMETERS                      113
#define ENGINE_R_RSA_NOT_IMPLEMENTED                     141
#define ENGINE_R_UNIMPLEMENTED_CIPHER                    146
#define ENGINE_R_UNIMPLEMENTED_DIGEST                    147
#define ENGINE_R_VERSION_INCOMPATIBILITY                 145

#ifdef  __cplusplus
}
#endif
#endif