lib/System/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 --- */


/* 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         }
#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) || defined(_MSC_VER)
#  define LT_CONC(s,t)  s##t
#else
#  define LT_CONC(s,t)  s/**/t
#endif

/* 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
#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


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


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


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));




/* --- 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;

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

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));



/* --- 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;
};

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));



/* --- 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")         \
    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")

/* 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. */
LT_SCOPE        int     lt_dladderror   LT_PARAMS((const char *diagnostic));
LT_SCOPE        int     lt_dlseterror   LT_PARAMS((int errorcode));




/* --- SOURCE COMPATIBILITY WITH OLD LIBLTDL --- */


#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 */