dlls/winecrt0/delay_load.c

   1 /*
   2  * Support for delayed imports
   3  *
   4  * Copyright 2005 Alexandre Julliard
   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 2.1 of the License, or (at your option) any later version.
  10  *
  11  * This library is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with this library; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
  19  */
  20
  21 #include <stdarg.h>
  22 #include "windef.h"
  23 #include "winbase.h"
  24
  25 struct ImgDelayDescr
  26 {
  27     DWORD_PTR               grAttrs;
  28     LPCSTR                  szName;
  29     HMODULE                *phmod;
  30     IMAGE_THUNK_DATA       *pIAT;
  31     const IMAGE_THUNK_DATA *pINT;
  32     const IMAGE_THUNK_DATA *pBoundIAT;
  33     const IMAGE_THUNK_DATA *pUnloadIAT;
  34     DWORD_PTR               dwTimeStamp;
  35 };
  36
  37 extern struct ImgDelayDescr __wine_spec_delay_imports[];
  38
  39 extern FARPROC WINAPI DelayLoadFailureHook( LPCSTR name, LPCSTR function );
  40
  41 FARPROC WINAPI DECLSPEC_HIDDEN __wine_spec_delay_load( unsigned int id )
  42 {
  43     struct ImgDelayDescr *descr = __wine_spec_delay_imports + HIWORD(id);
  44     WORD func = LOWORD(id);
  45     FARPROC proc;
  46
  47     if (!*descr->phmod) *descr->phmod = LoadLibraryA( descr->szName );
  48     if (!*descr->phmod ||
  49         !(proc = GetProcAddress( *descr->phmod, (LPCSTR)descr->pINT[func].u1.Function )))
  50         proc = DelayLoadFailureHook( descr->szName, (LPCSTR)descr->pINT[func].u1.Function );
  51     descr->pIAT[func].u1.Function = (ULONG_PTR)proc;
  52     return proc;
  53 }
  54
  55 #if defined(__GNUC__) && !defined(__APPLE__)  /* we can't support destructors properly on Mac OS */
  56 static void free_delay_imports(void) __attribute__((destructor));
  57 static void free_delay_imports(void)
  58 {
  59     struct ImgDelayDescr *descr;
  60     for (descr = __wine_spec_delay_imports; descr->szName; descr++)
  61         if (*descr->phmod) FreeLibrary( *descr->phmod );
  62 }
  63 #endif