dso.h

一个支持FTP,SFTP的客户端程序

/* dso.h -*- mode:C; c-file-style: "eay" -*- */
/* Written by Geoff Thorpe ([e-mail]) for the OpenSSL
 * project 2000.
 */
/* ====================================================================
 * Copyright (c) 2000 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
 *    [e-mail].
 *
 * 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
 * ([e-mail]).  This product includes software written by Tim
 * Hudson ([e-mail]).
 *
 */

#ifndef HEADER_DSO_H
#define HEADER_DSO_H

#include <openssl/crypto.h>

#ifdef __cplusplus
extern "C" {
#endif

/* These values are used as commands to DSO_ctrl() */
#define DSO_CTRL_GET_FLAGS	1
#define DSO_CTRL_SET_FLAGS	2
#define DSO_CTRL_OR_FLAGS	3

/* By default, DSO_load() will translate the provided filename into a form
 * typical for the platform (more specifically the DSO_METHOD) using the
 * dso_name_converter function of the method. Eg. win32 will transform "blah"
 * into "blah.dll", and dlfcn will transform it into "libblah.so". The
 * behaviour can be overriden by setting the name_converter callback in the DSO
 * object (using DSO_set_name_converter()). This callback could even utilise
 * the DSO_METHOD's converter too if it only wants to override behaviour for
 * one or two possible DSO methods. However, the following flag can be set in a
 * DSO to prevent *any* native name-translation at all - eg. if the caller has
 * prompted the user for a path to a driver library so the filename should be
 * interpreted as-is. */
#define DSO_FLAG_NO_NAME_TRANSLATION		0x01
/* An extra flag to give if only the extension should be added as
 * translation.  This is obviously only of importance on Unix and
 * other operating systems where the translation also may prefix
 * the name with something, like 'lib', and ignored everywhere else.
 * This flag is also ignored if DSO_FLAG_NO_NAME_TRANSLATION is used
 * at the same time. */
#define DSO_FLAG_NAME_TRANSLATION_EXT_ONLY	0x02

/* The following flag controls the translation of symbol names to upper
 * case.  This is currently only being implemented for OpenVMS.
 */
#define DSO_FLAG_UPCASE_SYMBOL			0x10

/* This flag loads the library with public symbols.
 * Meaning: The exported symbols of this library are public
 * to all libraries loaded after this library.
 * At the moment only implemented in unix.
 */
#define DSO_FLAG_GLOBAL_SYMBOLS			0x20


typedef void (*DSO_FUNC_TYPE)(void);

typedef struct dso_st DSO;

/* The function prototype used for method functions (or caller-provided
 * callbacks) that transform filenames. They are passed a DSO structure pointer
 * (or NULL if they are to be used independantly of a DSO object) and a
 * filename to transform. They should either return NULL (if there is an error
 * condition) or a newly allocated string containing the transformed form that
 * the caller will need to free with OPENSSL_free() when done. */
typedef char* (*DSO_NAME_CONVERTER_FUNC)(DSO *, const char *);
/* The function prototype used for method functions (or caller-provided
 * callbacks) that merge two file specifications. They are passed a
 * DSO structure pointer (or NULL if they are to be used independantly of
 * a DSO object) and two file specifications to merge. They should
 * either return NULL (if there is an error condition) or a newly allocated
 * string containing the result of merging that the caller will need
 * to free with OPENSSL_free() when done.
 * Here, merging means that bits and pieces are taken from each of the
 * file specifications and added together in whatever fashion that is
 * sensible for the DSO method in question.  The only rule that really
 * applies is that if the two specification contain pieces of the same
 * type, the copy from the string string takes priority.  One could see
 * it as the first specification is the one given by the user and the
 * second being a bunch of defaults to add on if they're missing in the
 * first. */
typedef char* (*DSO_MERGER_FUNC)(DSO *, const char *, const char *);

typedef struct dso_meth_st
	{
	const char *name;
	/* Loads a shared library, NB: new DSO_METHODs must ensure that a
	 * successful load populates the loaded_filename field, and likewise a
	 * successful unload OPENSSL_frees and NULLs it out. */
	int (*dso_load)(DSO *dso);
	/* Unloads a shared library */
	int (*dso_unload)(DSO *dso);
	/* Binds a variable */
	void *(*dso_bind_var)(DSO *dso, const char *symname);
	/* Binds a function - assumes a return type of DSO_FUNC_TYPE.
	 * This should be cast to the real function prototype by the
	 * caller. Platforms that don't have compatible representations
	 * for different prototypes (this is possible within ANSI C)
	 * are highly unlikely to have shared libraries at all, let
	 * alone a DSO_METHOD implemented for them. */
	DSO_FUNC_TYPE (*dso_bind_func)(DSO *dso, const char *symname);

/* I don't think this would actually be used in any circumstances. */
#if 0
	/* Unbinds a variable */
	int (*dso_unbind_var)(DSO *dso, char *symname, void *symptr);
	/* Unbinds a function */
	int (*dso_unbind_func)(DSO *dso, char *symname, DSO_FUNC_TYPE symptr);
#endif
	/* The generic (yuck) "ctrl()" function. NB: Negative return
	 * values (rather than zero) indicate errors. */
	long (*dso_ctrl)(DSO *dso, int cmd, long larg, void *parg);
	/* The default DSO_METHOD-specific function for converting filenames to
	 * a canonical native form. */
	DSO_NAME_CONVERTER_FUNC dso_name_converter;
	/* The default DSO_METHOD-specific function for converting filenames to
	 * a canonical native form. */
	DSO_MERGER_FUNC dso_merger;

	/* [De]Initialisation handlers. */
	int (*init)(DSO *dso);
	int (*finish)(DSO *dso);
	} DSO_METHOD;

/**********************************************************************/
/* The low-level handle type used to refer to a loaded shared library */

struct dso_st
	{
	DSO_METHOD *meth;
	/* Standard dlopen uses a (void *). Win32 uses a HANDLE. VMS
	 * doesn't use anything but will need to cache the filename
	 * for use in the dso_bind handler. All in all, let each
	 * method control its own destiny. "Handles" and such go in
	 * a STACK. */