libtool/libltdl/ltdl.h

/* ltdl.h -- generic dlopen functions
   Copyright (C) 1998-2000 Free Software Foundation, Inc.
   Originally by Thomas Tanner <tanner@ffii.org>
   This file is part of GNU Libtool.

This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2 of the License, or (at your option) any later version.

As a special exception to the GNU Lesser General Public License,
if you distribute this file as part of a program or library that
is built using GNU libtool, you may include it under the same
distribution terms that you use for the rest of that program.

This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307  USA
*/

/* Only include this header file once. */
#ifndef LTDL_H
#define LTDL_H 1

#include <sys/types.h>		/* for size_t declaration */


/* --- MACROS FOR PORTABILITY --- */


/* LTDL_BEGIN_C_DECLS should be used at the beginning of your declarations,
   so that C++ compilers don't mangle their names.  Use LTDL_END_C_DECLS at
   the end of C declarations. */
#ifdef __cplusplus
# define LT_BEGIN_C_DECLS	extern "C" {
# define LT_END_C_DECLS		}
#else
# define LT_BEGIN_C_DECLS	/* empty */
# define LT_END_C_DECLS		/* empty */
#endif

LT_BEGIN_C_DECLS


/* LT_PARAMS is a macro used to wrap function prototypes, so that compilers
   that don't understand ANSI C prototypes still work, and ANSI C
   compilers can issue warnings about type mismatches.  */
#if defined (__STDC__) || defined (_AIX) || (defined (__mips) && defined (_SYSTYPE_SVR4)) || defined(WIN32) || defined(__cplusplus)
# define LT_PARAMS(protos)	protos
# define lt_ptr		void*
#else
# define LT_PARAMS(protos)	()
# define lt_ptr		char*
#endif

/* LT_STMT_START/END are used to create macros which expand to a
   a single compound statement in a portable way.  */
#if defined (__GNUC__) && !defined (__STRICT_ANSI__) && !defined (__cplusplus)
#  define LT_STMT_START        (void)(
#  define LT_STMT_END          )
#else
#  if (defined (sun) || defined (__sun__))
#    define LT_STMT_START      if (1)
#    define LT_STMT_END        else (void)0
#  else
#    define LT_STMT_START      do
#    define LT_STMT_END        while (0)
#  endif
#endif

/* LT_CONC creates a new concatenated symbol for the compiler
   in a portable way.  */
#if defined(__STDC__) || defined(__cplusplus)
#  define LT_CONC(s,t)	s##t
#else
#  define LT_CONC(s,t)	s/**/t
#endif




/* --- WINDOWS SUPPORT --- */


/* Canonicalise Windows and Cygwin recognition macros.  */
#ifdef __CYGWIN32__
#  ifndef __CYGWIN__
#    define __CYGWIN__ __CYGWIN32__
#  endif
#endif
#if defined(_WIN32) || defined(WIN32)
#  ifndef __WINDOWS__
#    ifdef _WIN32
#      define __WINDOWS__ _WIN32
#    else
#      ifdef WIN32
#        define __WINDOWS__ WIN32
#      endif
#    endif
#  endif
#endif

#ifdef __WINDOWS__
#  ifndef __CYGWIN__
/* LT_DIRSEP_CHAR is accepted *in addition* to '/' as a directory
   separator when it is set. */
#    define LT_DIRSEP_CHAR	'\\'
#    define LT_PATHSEP_CHAR	';'
#  endif
#endif
#ifndef LT_PATHSEP_CHAR
#  define LT_PATHSEP_CHAR	':'
#endif

/* DLL building support on win32 hosts;  mostly to workaround their
   ridiculous implementation of data symbol exporting. */
#ifndef LT_SCOPE
#  ifdef __WINDOWS__
#    ifdef DLL_EXPORT		/* defined by libtool (if required) */
#      define LT_SCOPE	__declspec(dllexport)
#    endif
#    ifdef LIBLTDL_DLL_IMPORT	/* define if linking with this dll */
#      define LT_SCOPE	extern __declspec(dllimport)
#    endif
#  endif
#  ifndef LT_SCOPE		/* static linking or !__WINDOWS__ */
#    define LT_SCOPE	extern
#  endif
#endif




/* --- DYNAMIC MODULE LOADING API --- */


typedef	struct lt_dlhandle *lt_dlhandle;	/* A loaded module.  */

/* Initialisation and finalisation functions for libltdl. */
extern	int	    lt_dlinit		LT_PARAMS((void));
extern	int	    lt_dlexit		LT_PARAMS((void));

/* Module search path manipultation.  */
extern	int	    lt_dladdsearchdir	LT_PARAMS((const char *search_dir));
extern	int 	    lt_dlsetsearchpath	LT_PARAMS((const char *search_path));
extern	const char *lt_dlgetsearchpath	LT_PARAMS((void));

/* Portable libltdl versions of the system dlopen() API. */
extern	lt_dlhandle lt_dlopen		LT_PARAMS((const char *filename));
extern	lt_dlhandle lt_dlopenext	LT_PARAMS((const char *filename));
extern	lt_ptr	    lt_dlsym		LT_PARAMS((lt_dlhandle handle,
						     const char *name));
extern	const char *lt_dlerror		LT_PARAMS((void));
extern	int	    lt_dlclose		LT_PARAMS((lt_dlhandle handle));

/* Pointers to memory management functions to be used by libltdl. */
LT_SCOPE  lt_ptr   (*lt_dlmalloc)	LT_PARAMS((size_t size));
LT_SCOPE  void	   (*lt_dlfree)		LT_PARAMS((lt_ptr ptr));




/* --- PRELOADED MODULE SUPPORT --- */


/* A preopened symbol. Arrays of this type comprise the exported
   symbols for a dlpreopened module. */
typedef struct {
  const char *name;
  lt_ptr      address;
} lt_dlsymlist;

extern	int	lt_dlpreload	LT_PARAMS((const lt_dlsymlist *preloaded));
extern	int	lt_dlpreload_default
				LT_PARAMS((const lt_dlsymlist *preloaded));

#define LTDL_SET_PRELOADED_SYMBOLS() 		LT_STMT_START{	\
	extern const lt_dlsymlist lt_preloaded_symbols[];		\
	lt_dlpreload_default(lt_preloaded_symbols);			\
						}LT_STMT_END




/* --- MODULE INFORMATION --- */


/* Read only information pertaining to a loaded module. */
typedef	struct {
  char	*filename;		/* file name */
  char	*name;			/* module name */
  int	ref_count;		/* number of times lt_dlopened minus
				   number of times lt_dlclosed. */
} lt_dlinfo;

extern	const lt_dlinfo	 *lt_dlgetinfo    LT_PARAMS((lt_dlhandle handle));
extern	int		  lt_dlforeach    LT_PARAMS((
				int (*func) (lt_dlhandle handle, lt_ptr data),
				lt_ptr data));




/* --- USER MODULE LOADER API --- */


typedef	struct lt_dlloader	lt_dlloader;
typedef lt_ptr			lt_user_data;
typedef lt_ptr			lt_module;

/* Function pointer types for creating user defined module loaders. */
typedef lt_module   lt_module_open	LT_PARAMS((lt_user_data loader_data,
					    const char *filename));
typedef int	    lt_module_close	LT_PARAMS((lt_user_data loader_data,
					    lt_module handle));
typedef lt_ptr	    lt_find_sym		LT_PARAMS((lt_user_data loader_data,
					    lt_module handle,
					    const char *symbol));
typedef int	    lt_dlloader_exit	LT_PARAMS((lt_user_data loader_data));

struct lt_user_dlloader {
  const char	       *sym_prefix;
  lt_module_open       *module_open;
  lt_module_close      *module_close;
  lt_find_sym	       *find_sym;
  lt_dlloader_exit     *dlloader_exit;
  lt_user_data		dlloader_data;
};

extern	lt_dlloader    *lt_dlloader_next    LT_PARAMS((lt_dlloader *place));
extern	lt_dlloader    *lt_dlloader_find    LT_PARAMS((
						const char *loader_name));
extern	const char     *lt_dlloader_name    LT_PARAMS((lt_dlloader *place));
extern	lt_user_data   *lt_dlloader_data    LT_PARAMS((lt_dlloader *place));
extern	int		lt_dlloader_add     LT_PARAMS((lt_dlloader *place,
						const struct lt_user_dlloader *dlloader,
						const char *loader_name));
extern	int		lt_dlloader_remove  LT_PARAMS((
						const char *loader_name));



/* --- ERROR MESSAGE HANDLING --- */


/* Defining error strings alongside their symbolic names in a macro in
   this way allows us to expand the macro in different contexts with
   confidence that the enumeration of symbolic names will map correctly
   onto the table of error strings.  */
#define lt_dlerror_table						\
    LT_ERROR(UNKNOWN,		    "unknown error")			\
    LT_ERROR(DLOPEN_NOT_SUPPORTED,  "dlopen support not available")	\
    LT_ERROR(INVALID_LOADER,	    "invalid loader")			\
    LT_ERROR(INIT_LOADER,	    "loader initialization failed")	\
    LT_ERROR(REMOVE_LOADER,	    "loader removal failed")		\
    LT_ERROR(FILE_NOT_FOUND,	    "file not found")			\
    LT_ERROR(DEPLIB_NOT_FOUND,      "dependency library not found")	\
    LT_ERROR(NO_SYMBOLS,	    "no symbols defined")		\
    LT_ERROR(CANNOT_OPEN,	    "can't open the module")		\
    LT_ERROR(CANNOT_CLOSE,	    "can't close the module")		\
    LT_ERROR(SYMBOL_NOT_FOUND,      "symbol not found")			\
    LT_ERROR(NO_MEMORY,		    "not enough memory")		\
    LT_ERROR(INVALID_HANDLE,	    "invalid module handle")		\
    LT_ERROR(BUFFER_OVERFLOW,	    "internal buffer overflow")		\
    LT_ERROR(INVALID_ERRORCODE,     "invalid errorcode")		\
    LT_ERROR(SHUTDOWN,		    "library already shutdown")

/* Enumerate the symbolic error names. */
enum {
#define LT_ERROR(name, diagnostic)	LT_CONC(LT_ERROR_, name),
	lt_dlerror_table
#undef LT_ERROR

	LT_ERROR_MAX
};

/* These functions are only useful from inside custom module loaders. */
extern	int	lt_dladderror	LT_PARAMS((const char *diagnostic));
extern	int	lt_dlseterror	LT_PARAMS((int errorcode));

#ifdef LT_NON_POSIX_NAMESPACE
#  define lt_ptr_t		lt_ptr
#  define lt_module_t		lt_module
#  define lt_module_open_t	lt_module_open
#  define lt_module_close_t	lt_module_close
#  define lt_find_sym_t		lt_find_sym
#  define lt_dlloader_exit_t	lt_dlloader_exit
#  define lt_dlloader_t		lt_dlloader
#  define lt_dlloader_data_t	lt_user_data
#endif

LT_END_C_DECLS

#endif /* !LTDL_H */