share/libtool/libltdl/ltdl.h

   1 /* ltdl.h -- generic dlopen functions
   2    Copyright (C) 1998-2000 Free Software Foundation, Inc.
   3    Originally by Thomas Tanner <tanner@ffii.org>
   4    This file is part of GNU Libtool.
   5
   6 This library is free software; you can redistribute it and/or
   7 modify it under the terms of the GNU Lesser General Public
   8 License as published by the Free Software Foundation; either
   9 version 2 of the License, or (at your option) any later version.
  10
  11 As a special exception to the GNU Lesser General Public License,
  12 if you distribute this file as part of a program or library that
  13 is built using GNU libtool, you may include it under the same
  14 distribution terms that you use for the rest of that program.
  15
  16 This library is distributed in the hope that it will be useful,
  17 but WITHOUT ANY WARRANTY; without even the implied warranty of
  18 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  19 Lesser General Public License for more details.
  20
  21 You should have received a copy of the GNU Lesser General Public
  22 License along with this library; if not, write to the Free
  23 Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  24 02111-1307  USA
  25 */
  26
  27 /* Only include this header file once. */
  28 #ifndef LTDL_H
  29 #define LTDL_H 1
  30
  31 #include <sys/types.h>          /* for size_t declaration */
  32
  33 \f
  34 /* --- MACROS FOR PORTABILITY --- */
  35
  36
  37 /* Saves on those hard to debug '\0' typos....  */
  38 #define LT_EOS_CHAR     '\0'
  39
  40 /* LTDL_BEGIN_C_DECLS should be used at the beginning of your declarations,
  41    so that C++ compilers don't mangle their names.  Use LTDL_END_C_DECLS at
  42    the end of C declarations. */
  43 #ifdef __cplusplus
  44 # define LT_BEGIN_C_DECLS       extern "C" {
  45 # define LT_END_C_DECLS         }
  46 #else
  47 # define LT_BEGIN_C_DECLS       /* empty */
  48 # define LT_END_C_DECLS         /* empty */
  49 #endif
  50
  51 LT_BEGIN_C_DECLS
  52
  53
  54 /* LT_PARAMS is a macro used to wrap function prototypes, so that compilers
  55    that don't understand ANSI C prototypes still work, and ANSI C
  56    compilers can issue warnings about type mismatches.  */
  57 #if defined (__STDC__) || defined (_AIX) || (defined (__mips) && defined (_SYSTYPE_SVR4)) || defined(WIN32) || defined(__cplusplus)
  58 # define LT_PARAMS(protos)      protos
  59 # define lt_ptr         void*
  60 #else
  61 # define LT_PARAMS(protos)      ()
  62 # define lt_ptr         char*
  63 #endif
  64
  65 /* LT_STMT_START/END are used to create macros which expand to a
  66    a single compound statement in a portable way.  */
  67 #if defined (__GNUC__) && !defined (__STRICT_ANSI__) && !defined (__cplusplus)
  68 #  define LT_STMT_START        (void)(
  69 #  define LT_STMT_END          )
  70 #else
  71 #  if (defined (sun) || defined (__sun__))
  72 #    define LT_STMT_START      if (1)
  73 #    define LT_STMT_END        else (void)0
  74 #  else
  75 #    define LT_STMT_START      do
  76 #    define LT_STMT_END        while (0)
  77 #  endif
  78 #endif
  79
  80 /* LT_CONC creates a new concatenated symbol for the compiler
  81    in a portable way.  */
  82 #if defined(__STDC__) || defined(__cplusplus)
  83 #  define LT_CONC(s,t)  s##t
  84 #else
  85 #  define LT_CONC(s,t)  s/**/t
  86 #endif
  87
  88 /* LT_STRLEN can be used safely on NULL pointers.  */
  89 #define LT_STRLEN(s)    (((s) && (s)[0]) ? strlen (s) : 0)
  90
  91
  92 \f
  93 /* --- WINDOWS SUPPORT --- */
  94
  95
  96 /* Canonicalise Windows and Cygwin recognition macros.  */
  97 #ifdef __CYGWIN32__
  98 #  ifndef __CYGWIN__
  99 #    define __CYGWIN__ __CYGWIN32__
 100 #  endif
 101 #endif
 102 #if defined(_WIN32) || defined(WIN32)
 103 #  ifndef __WINDOWS__
 104 #    ifdef _WIN32
 105 #      define __WINDOWS__ _WIN32
 106 #    else
 107 #      ifdef WIN32
 108 #        define __WINDOWS__ WIN32
 109 #      endif
 110 #    endif
 111 #  endif
 112 #endif
 113
 114 #ifdef __WINDOWS__
 115 #  ifndef __CYGWIN__
 116 /* LT_DIRSEP_CHAR is accepted *in addition* to '/' as a directory
 117    separator when it is set. */
 118 #    define LT_DIRSEP_CHAR      '\\'
 119 #    define LT_PATHSEP_CHAR     ';'
 120 #  endif
 121 #endif
 122 #ifndef LT_PATHSEP_CHAR
 123 #  define LT_PATHSEP_CHAR       ':'
 124 #endif
 125
 126 /* DLL building support on win32 hosts;  mostly to workaround their
 127    ridiculous implementation of data symbol exporting. */
 128 #ifndef LT_SCOPE
 129 #  ifdef __WINDOWS__
 130 #    ifdef DLL_EXPORT           /* defined by libtool (if required) */
 131 #      define LT_SCOPE  __declspec(dllexport)
 132 #    endif
 133 #    ifdef LIBLTDL_DLL_IMPORT   /* define if linking with this dll */
 134 #      define LT_SCOPE  extern __declspec(dllimport)
 135 #    endif
 136 #  endif
 137 #  ifndef LT_SCOPE              /* static linking or !__WINDOWS__ */
 138 #    define LT_SCOPE    extern
 139 #  endif
 140 #endif
 141
 142
 143
 144 \f
 145 /* --- DYNAMIC MODULE LOADING API --- */
 146
 147
 148 typedef struct lt_dlhandle_struct *lt_dlhandle; /* A loaded module.  */
 149
 150 /* Initialisation and finalisation functions for libltdl. */
 151 extern  int         lt_dlinit           LT_PARAMS((void));
 152 extern  int         lt_dlexit           LT_PARAMS((void));
 153
 154 /* Module search path manipulation.  */
 155 extern  int         lt_dladdsearchdir    LT_PARAMS((const char *search_dir));
 156 extern  int         lt_dlinsertsearchdir LT_PARAMS((const char *before,
 157                                                     const char *search_dir));
 158 extern  int         lt_dlsetsearchpath   LT_PARAMS((const char *search_path));
 159 extern  const char *lt_dlgetsearchpath   LT_PARAMS((void));
 160 extern  int         lt_dlforeachfile     LT_PARAMS((
 161                         const char *search_path,
 162                         int (*func) (const char *filename, lt_ptr data),
 163                         lt_ptr data));
 164
 165 /* Portable libltdl versions of the system dlopen() API. */
 166 extern  lt_dlhandle lt_dlopen           LT_PARAMS((const char *filename));
 167 extern  lt_dlhandle lt_dlopenext        LT_PARAMS((const char *filename));
 168 extern  lt_ptr      lt_dlsym            LT_PARAMS((lt_dlhandle handle,
 169                                                      const char *name));
 170 extern  const char *lt_dlerror          LT_PARAMS((void));
 171 extern  int         lt_dlclose          LT_PARAMS((lt_dlhandle handle));
 172
 173 /* Module residency management. */
 174 extern  int         lt_dlmakeresident   LT_PARAMS((lt_dlhandle handle));
 175 extern  int         lt_dlisresident     LT_PARAMS((lt_dlhandle handle));
 176
 177
 178
 179 \f
 180 /* --- MUTEX LOCKING --- */
 181
 182
 183 typedef void    lt_dlmutex_lock         LT_PARAMS((void));
 184 typedef void    lt_dlmutex_unlock       LT_PARAMS((void));
 185 typedef void    lt_dlmutex_seterror     LT_PARAMS((const char *errmsg));
 186 typedef const char *lt_dlmutex_geterror LT_PARAMS((void));
 187
 188 extern  int     lt_dlmutex_register     LT_PARAMS((lt_dlmutex_lock *lock,
 189                                             lt_dlmutex_unlock *unlock,
 190                                             lt_dlmutex_seterror *seterror,
 191                                             lt_dlmutex_geterror *geterror));
 192
 193
 194
 195 \f
 196 /* --- MEMORY HANDLING --- */
 197
 198
 199 /* By default, the realloc function pointer is set to our internal
 200    realloc implementation which iself uses lt_dlmalloc and lt_dlfree.
 201    libltdl relies on a featureful realloc, but if you are sure yours
 202    has the right semantics then you can assign it directly.  Generally,
 203    it is safe to assign just a malloc() and a free() function.  */
 204 LT_SCOPE  lt_ptr   (*lt_dlmalloc)       LT_PARAMS((size_t size));
 205 LT_SCOPE  lt_ptr   (*lt_dlrealloc)      LT_PARAMS((lt_ptr ptr, size_t size));
 206 LT_SCOPE  void     (*lt_dlfree)         LT_PARAMS((lt_ptr ptr));
 207
 208
 209
 210 \f
 211 /* --- PRELOADED MODULE SUPPORT --- */
 212
 213
 214 /* A preopened symbol. Arrays of this type comprise the exported
 215    symbols for a dlpreopened module. */
 216 typedef struct {
 217   const char *name;
 218   lt_ptr      address;
 219 } lt_dlsymlist;
 220
 221 extern  int     lt_dlpreload    LT_PARAMS((const lt_dlsymlist *preloaded));
 222 extern  int     lt_dlpreload_default
 223                                 LT_PARAMS((const lt_dlsymlist *preloaded));
 224
 225 #define LTDL_SET_PRELOADED_SYMBOLS()            LT_STMT_START{  \
 226         extern const lt_dlsymlist lt_preloaded_symbols[];               \
 227         lt_dlpreload_default(lt_preloaded_symbols);                     \
 228                                                 }LT_STMT_END
 229
 230
 231
 232 \f
 233 /* --- MODULE INFORMATION --- */
 234
 235
 236 /* Read only information pertaining to a loaded module. */
 237 typedef struct {
 238   char  *filename;              /* file name */
 239   char  *name;                  /* module name */
 240   int   ref_count;              /* number of times lt_dlopened minus
 241                                    number of times lt_dlclosed. */
 242 } lt_dlinfo;
 243
 244 extern  const lt_dlinfo *lt_dlgetinfo       LT_PARAMS((lt_dlhandle handle));
 245 extern  lt_dlhandle     lt_dlhandle_next    LT_PARAMS((lt_dlhandle place));
 246 extern  int             lt_dlforeach        LT_PARAMS((
 247                                 int (*func) (lt_dlhandle handle, lt_ptr data),
 248                                 lt_ptr data));
 249
 250 /* Associating user data with loaded modules. */
 251 typedef unsigned lt_dlcaller_id;
 252
 253 extern  lt_dlcaller_id  lt_dlcaller_register  LT_PARAMS((void));
 254 extern  lt_ptr          lt_dlcaller_set_data  LT_PARAMS((lt_dlcaller_id key,
 255                                                 lt_dlhandle handle,
 256                                                 lt_ptr data));
 257 extern  lt_ptr          lt_dlcaller_get_data  LT_PARAMS((lt_dlcaller_id key,
 258                                                 lt_dlhandle handle));
 259
 260
 261 \f
 262 /* --- USER MODULE LOADER API --- */
 263
 264
 265 typedef struct lt_dlloader      lt_dlloader;
 266 typedef lt_ptr                  lt_user_data;
 267 typedef lt_ptr                  lt_module;
 268
 269 /* Function pointer types for creating user defined module loaders. */
 270 typedef lt_module   lt_module_open      LT_PARAMS((lt_user_data loader_data,
 271                                             const char *filename));
 272 typedef int         lt_module_close     LT_PARAMS((lt_user_data loader_data,
 273                                             lt_module handle));
 274 typedef lt_ptr      lt_find_sym         LT_PARAMS((lt_user_data loader_data,
 275                                             lt_module handle,
 276                                             const char *symbol));
 277 typedef int         lt_dlloader_exit    LT_PARAMS((lt_user_data loader_data));
 278
 279 struct lt_user_dlloader {
 280   const char           *sym_prefix;
 281   lt_module_open       *module_open;
 282   lt_module_close      *module_close;
 283   lt_find_sym          *find_sym;
 284   lt_dlloader_exit     *dlloader_exit;
 285   lt_user_data          dlloader_data;
 286 };
 287
 288 extern  lt_dlloader    *lt_dlloader_next    LT_PARAMS((lt_dlloader *place));
 289 extern  lt_dlloader    *lt_dlloader_find    LT_PARAMS((
 290                                                 const char *loader_name));
 291 extern  const char     *lt_dlloader_name    LT_PARAMS((lt_dlloader *place));
 292 extern  lt_user_data   *lt_dlloader_data    LT_PARAMS((lt_dlloader *place));
 293 extern  int             lt_dlloader_add     LT_PARAMS((lt_dlloader *place,
 294                                 const struct lt_user_dlloader *dlloader,
 295                                 const char *loader_name));
 296 extern  int             lt_dlloader_remove  LT_PARAMS((
 297                                                 const char *loader_name));
 298
 299
 300 \f
 301 /* --- ERROR MESSAGE HANDLING --- */
 302
 303
 304 /* Defining error strings alongside their symbolic names in a macro in
 305    this way allows us to expand the macro in different contexts with
 306    confidence that the enumeration of symbolic names will map correctly
 307    onto the table of error strings.  */
 308 #define lt_dlerror_table                                                \
 309     LT_ERROR(UNKNOWN,               "unknown error")                    \
 310     LT_ERROR(DLOPEN_NOT_SUPPORTED,  "dlopen support not available")     \
 311     LT_ERROR(INVALID_LOADER,        "invalid loader")                   \
 312     LT_ERROR(INIT_LOADER,           "loader initialization failed")     \
 313     LT_ERROR(REMOVE_LOADER,         "loader removal failed")            \
 314     LT_ERROR(FILE_NOT_FOUND,        "file not found")                   \
 315     LT_ERROR(DEPLIB_NOT_FOUND,      "dependency library not found")     \
 316     LT_ERROR(NO_SYMBOLS,            "no symbols defined")               \
 317     LT_ERROR(CANNOT_OPEN,           "can't open the module")            \
 318     LT_ERROR(CANNOT_CLOSE,          "can't close the module")           \
 319     LT_ERROR(SYMBOL_NOT_FOUND,      "symbol not found")                 \
 320     LT_ERROR(NO_MEMORY,             "not enough memory")                \
 321     LT_ERROR(INVALID_HANDLE,        "invalid module handle")            \
 322     LT_ERROR(BUFFER_OVERFLOW,       "internal buffer overflow")         \
 323     LT_ERROR(INVALID_ERRORCODE,     "invalid errorcode")                \
 324     LT_ERROR(SHUTDOWN,              "library already shutdown")         \
 325     LT_ERROR(CLOSE_RESIDENT_MODULE, "can't close resident module")      \
 326     LT_ERROR(INVALID_MUTEX_ARGS,    "invalid mutex handler registration") \
 327     LT_ERROR(INVALID_POSITION,      "invalid search path insert position")
 328
 329 /* Enumerate the symbolic error names. */
 330 enum {
 331 #define LT_ERROR(name, diagnostic)      LT_CONC(LT_ERROR_, name),
 332         lt_dlerror_table
 333 #undef LT_ERROR
 334
 335         LT_ERROR_MAX
 336 };
 337
 338 /* These functions are only useful from inside custom module loaders. */
 339 extern  int     lt_dladderror   LT_PARAMS((const char *diagnostic));
 340 extern  int     lt_dlseterror   LT_PARAMS((int errorcode));
 341
 342
 343
 344 \f
 345 /* --- SOURCE COMPATIBILITY WITH OLD LIBLTDL --- */
 346
 347
 348 #ifdef LT_NON_POSIX_NAMESPACE
 349 #  define lt_ptr_t              lt_ptr
 350 #  define lt_module_t           lt_module
 351 #  define lt_module_open_t      lt_module_open
 352 #  define lt_module_close_t     lt_module_close
 353 #  define lt_find_sym_t         lt_find_sym
 354 #  define lt_dlloader_exit_t    lt_dlloader_exit
 355 #  define lt_dlloader_t         lt_dlloader
 356 #  define lt_dlloader_data_t    lt_user_data
 357 #endif
 358
 359 LT_END_C_DECLS
 360
 361 #endif /* !LTDL_H */