ltdl.h   [plain text]

/* ltdl.h -- generic dlopen functions
   Copyright (C) 1998-2000 Free Software Foundation, Inc.
   Originally by Thomas Tanner <>
   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
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., 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301  USA

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

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


/* Saves on those hard to debug '\0' typos....  */
#define LT_EOS_CHAR	'\0'

/* 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		}
# define LT_BEGIN_C_DECLS	/* empty */
# define LT_END_C_DECLS		/* empty */


/* 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*
# define LT_PARAMS(protos)	()
# define lt_ptr		char*

/* 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          )
#  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

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

/* LT_STRLEN can be used safely on NULL pointers.  */
#define LT_STRLEN(s)	(((s) && (s)[0]) ? strlen (s) : 0)

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

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

/* 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

#if defined(_MSC_VER) /* Visual Studio */
#  define R_OK 4


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

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

/* Module search path manipulation.  */
LT_SCOPE	int	    lt_dladdsearchdir	 LT_PARAMS((const char *search_dir));
LT_SCOPE	int	    lt_dlinsertsearchdir LT_PARAMS((const char *before,
						    const char *search_dir));
LT_SCOPE	int 	    lt_dlsetsearchpath	 LT_PARAMS((const char *search_path));
LT_SCOPE	const char *lt_dlgetsearchpath	 LT_PARAMS((void));
LT_SCOPE	int	    lt_dlforeachfile	 LT_PARAMS((
			const char *search_path,
			int (*func) (const char *filename, lt_ptr data),
			lt_ptr data));

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

/* Module residency management. */
LT_SCOPE	int	    lt_dlmakeresident	LT_PARAMS((lt_dlhandle handle));
LT_SCOPE	int	    lt_dlisresident	LT_PARAMS((lt_dlhandle handle));

/* --- MUTEX LOCKING --- */

typedef void	lt_dlmutex_lock		LT_PARAMS((void));
typedef void	lt_dlmutex_unlock	LT_PARAMS((void));
typedef void	lt_dlmutex_seterror	LT_PARAMS((const char *errmsg));
typedef const char *lt_dlmutex_geterror	LT_PARAMS((void));

LT_SCOPE	int	lt_dlmutex_register	LT_PARAMS((lt_dlmutex_lock *lock,
					    lt_dlmutex_unlock *unlock,
					    lt_dlmutex_seterror *seterror,
					    lt_dlmutex_geterror *geterror));

/* --- MEMORY HANDLING --- */

/* By default, the realloc function pointer is set to our internal
   realloc implementation which iself uses lt_dlmalloc and lt_dlfree.
   libltdl relies on a featureful realloc, but if you are sure yours
   has the right semantics then you can assign it directly.  Generally,
   it is safe to assign just a malloc() and a free() function.  */
LT_SCOPE  lt_ptr   (*lt_dlmalloc)	LT_PARAMS((size_t size));
LT_SCOPE  lt_ptr   (*lt_dlrealloc)	LT_PARAMS((lt_ptr ptr, size_t size));
LT_SCOPE  void	   (*lt_dlfree)		LT_PARAMS((lt_ptr ptr));


/* 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;

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

	extern const lt_dlsymlist lt_preloaded_symbols[];		\
	lt_dlpreload_default(lt_preloaded_symbols);			\


/* 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;

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

/* Associating user data with loaded modules. */
typedef unsigned lt_dlcaller_id;

LT_SCOPE	lt_dlcaller_id	lt_dlcaller_register  LT_PARAMS((void));
LT_SCOPE	lt_ptr		lt_dlcaller_set_data  LT_PARAMS((lt_dlcaller_id key,
						lt_dlhandle handle,
						lt_ptr data));
LT_SCOPE	lt_ptr		lt_dlcaller_get_data  LT_PARAMS((lt_dlcaller_id key,
						lt_dlhandle handle));


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;

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


/* 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")		\
    LT_ERROR(CLOSE_RESIDENT_MODULE, "can't close resident module")	\
    LT_ERROR(INVALID_MUTEX_ARGS,    "invalid mutex handler registration") \
    LT_ERROR(INVALID_POSITION,	    "invalid search path insert position") \
    LT_ERROR(FR_DEPLIB,		    "dep lib loading bug, please report to")

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


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


#  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 /* !LTDL_H */