Source code of Windows XP (NT5)
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/***
*crtdll.c - CRT initialization for a DLL using the MSVCRT* model of C run-time
*
* Copyright (c) 1991-2001, Microsoft Corporation. All rights reserved.
*
*Purpose:
* This module contains the initialization entry point for the C run-time
* stub in this DLL. All C run-time code is located in the C Run-Time
* Library DLL "MSVCRT*.DLL", except for a little bit of start-up code in
* the EXE, and this code in each DLL. This code is necessary to invoke
* the C++ constructors for the C++ code in this DLL.
*
* This entry point should either be specified as the DLL initialization
* entry point, or else it must be called by the DLL initialization entry
* point of the DLL with the same arguments that the entry point receives.
*
*Revision History:
* 05-19-92 SKS Initial version
* 08-01-92 SRW winxcpt.h replaced bu excpt.h which is included by oscalls.h
* 09-16-92 SKS Prepare for C8 C++ for MIPS by calling C++ constructors
* 09-29-92 SKS _CRT_DLL must be a WINAPI function!
* 04-06-93 SKS Replace _CRTAPI* with _cdecl
* 04-14-93 SKS _DllMainCRTStartup replaces _CRT_INIT
* 04-20-93 SKS Restore _CRT_INIT, must co-exist with DllMainCRTStartup
* 05-24-93 SKS Add indirect definitions of _onexit/atexit.
* 06-08-93 GJF Added __proc_attached flag.
* 06-08-93 SKS Clean up failure handling in _CRT_INIT
* 10-26-93 GJF Replaced PF with _PVFV (defined in internal.h).
* 05-02-94 GJF Add _wDllMainCRTStartup thunk.
* 05-19-94 GJF For Win32S version, only create the onexit-table and
* do the C++ constructors for the first process that
* attaches. Similarly, only execute the table entries
* when the last process detaches. Also, removed bogus
* incrementing and decrementing of __proc_attached flag
* in _DllMainCRTStartup.
* 05-27-94 GJF Replaced conditional compilation on DLL_FOR_WIN32S
* with a runtime test for Win32s.
* 06-04-94 GJF Fixed test for first process attach in Win32s.
* 06-06-94 GJF Use GlobalAlloc for Win32s.
* 06-08-94 SKS Add functn pointer _pRawDllMain, called around DllMain.
* 07-18-94 GJF Must specify GMEM_SHARE in GlobalAlloc.
* 11-08-94 SKS Free __onexitbegin (under !Win32s) to fix memory leak
* 12-13-94 GJF Made Win32s support conditional on _M_IX86.
* 12-13-94 SKS Import the value of "_adjust_fdiv" from the CRTL DLL
* 12-27-94 CFW Remove unused _wDll support.
* 01-10-95 CFW Debug CRT allocs.
* 02-22-95 JWM Spliced in PMAC code.
* 05-24-95 CFW Return value from DllInit.
* 07-24-95 CFW Change PMac onexit malloc to _malloc_crt.
* 11-15-95 BWT Win32s isn't interesting for NT.
* 05-14-96 GJF Changed how failure during process attach is handled.
* 06-27-96 GJF Purged Win32s support (removed __win32sflag). Replaced
* defined(_WIN32) with !defined(_MAC). Removed NT_BUILD.
* 02-01-99 GJF Slight change to terminator execution loop to allow
* terminators to register more terminators.
* 04-28-99 PML Wrap __declspec(allocate()) in _CRTALLOC macro.
* 05-11-99 KBF Wrap RTC support in #ifdef.
* 05-17-99 PML Remove all Macintosh support.
*
*******************************************************************************/
#ifdef CRTDLL
/*
* SPECIAL BUILD MACRO! Note that crtexe.c (and crtexew.c) is linked in with
* the client's code. It does not go into crtdll.dll! Therefore, it must be
* built under the _DLL switch (like user code) and CRTDLL must be undefined.
*/
#undef CRTDLL
#undef _DLL
#define _DLL
#include <cruntime.h>
#include <oscalls.h>
#include <internal.h>
#include <stdlib.h>
#define _DECL_DLLMAIN /* enable prototypes for DllMain and _CRT_INIT */
#include <process.h>
#include <dbgint.h>
#include <rtcapi.h>
#include <sect_attribs.h>
#ifdef _M_IX86
/*
* The local copy of the Pentium FDIV adjustment flag
* and the address of the flag in MSVCRT*.DLL.
*/
extern int _adjust_fdiv;
extern int * _imp___adjust_fdiv;
#endif
/*
* routine in DLL to do initialization (in this case, C++ constructors)
*/
extern void __cdecl _initterm(_PVFV *, _PVFV *);
/*
* pointers to initialization sections
*/
extern _CRTALLOC(".CRT$XCA") _PVFV __xc_a[];
extern _CRTALLOC(".CRT$XCZ") _PVFV __xc_z[]; /* C++ initializers */
/*
* flag set iff _CRTDLL_INIT was called with DLL_PROCESS_ATTACH
*/
static int __proc_attached = 0;
/*
* Pointers to beginning and end of the table of function pointers manipulated
* by _onexit()/atexit(). The atexit/_onexit code is shared for both EXE's and
* DLL's but different behavior is required. These values are initialized to
* 0 by default and will be set to point to a malloc-ed memory block to mark
* this module as an DLL.
*/
extern _PVFV *__onexitbegin;
extern _PVFV *__onexitend;
/*
* User routine DllMain is called on all notifications
*/
extern BOOL WINAPI DllMain(
HANDLE hDllHandle,
DWORD dwReason,
LPVOID lpreserved
) ;
/* _pRawDllMain MUST be a common variable, not extern nor initialized! */
BOOL (WINAPI *_pRawDllMain)(HANDLE, DWORD, LPVOID);
/***
*BOOL WINAPI _CRT_INIT(hDllHandle, dwReason, lpreserved) - C++ DLL
* initialization.
*BOOL WINAPI _DllMainCRTStartup(hDllHandle, dwReason, lpreserved) - C++ DLL
* initialization.
*
*Purpose:
* This is the entry point for DLL's linked with the C/C++ run-time libs.
* This routine does the C runtime initialization for a DLL linked with
* MSVCRT.LIB (whose C run-time code is thus in MSVCRT*.DLL.)
* It will call the user notification routine DllMain on all 4 types of
* DLL notifications. The return code from this routine is the return
* code from the user notification routine.
*
* On DLL_PROCESS_ATTACH, the C++ constructors for the DLL will be called.
*
* On DLL_PROCESS_DETACH, the C++ destructors and _onexit/atexit routines
* will be called.
*
*Entry:
*
*Exit:
*
*******************************************************************************/
BOOL WINAPI _CRT_INIT(
HANDLE hDllHandle,
DWORD dwReason,
LPVOID lpreserved
)
{
/*
* If this is a process detach notification, check that there has
* been a prior (successful) process attachment.
*/
if ( dwReason == DLL_PROCESS_DETACH ) {
if ( __proc_attached > 0 )
__proc_attached--;
else
/*
* no prior process attach. just return failure.
*/
return FALSE;
}
#ifdef _M_IX86
/*
* Set the local copy of the Pentium FDIV adjustment flag
*/
_adjust_fdiv = * _imp___adjust_fdiv;
#endif
/*
* do C++ constructors (initializers) specific to this DLL
*/
if ( dwReason == DLL_PROCESS_ATTACH ) {
/*
* create the onexit table.
*/
if ( (__onexitbegin = (_PVFV *)_malloc_crt(32 * sizeof(_PVFV)))
== NULL )
/*
* cannot allocate minimal required
* size. generate failure to load DLL
*/
return FALSE;
*(__onexitbegin) = (_PVFV) NULL;
__onexitend = __onexitbegin;
/*
* Run the RTC initialization code for this DLL
*/
#ifdef _RTC
_RTC_Initialize();
atexit(_RTC_Terminate);
#endif
/*
* Invoke C++ constructors
*/
_initterm(__xc_a,__xc_z);
/*
* Increment the process attached flag.
*/
__proc_attached++;
}
else if ( dwReason == DLL_PROCESS_DETACH ) {
/*
* Any basic clean-up code that goes here must be
* duplicated below in _DllMainCRTStartup for the
* case where the user's DllMain() routine fails on a
* Process Attach notification. This does not include
* calling user C++ destructors, etc.
*/
/*
* do _onexit/atexit() terminators
* (if there are any)
*
* These terminators MUST be executed in
* reverse order (LIFO)!
*
* NOTE:
* This code assumes that __onexitbegin
* points to the first valid onexit()
* entry and that __onexitend points
* past the last valid entry. If
* __onexitbegin == __onexitend, the
* table is empty and there are no
* routines to call.
*/
if (__onexitbegin) {
while ( --__onexitend >= __onexitbegin )
/*
* if current table entry is not
* NULL, call thru it.
*/
if ( *__onexitend != NULL )
(**__onexitend)();
/*
* free the block holding onexit table to
* avoid memory leaks. Also zero the ptr
* variable so that it is clearly cleaned up.
*/
_free_crt ( __onexitbegin ) ;
__onexitbegin = NULL ;
}
}
return TRUE;
}
BOOL WINAPI _DllMainCRTStartup(
HANDLE hDllHandle,
DWORD dwReason,
LPVOID lpreserved
)
{
BOOL retcode = TRUE;
/*
* If this is a process detach notification, check that there has
* been a prior process attach notification.
*/
if ( (dwReason == DLL_PROCESS_DETACH) && (__proc_attached == 0) )
return FALSE;
if ( dwReason == DLL_PROCESS_ATTACH || dwReason == DLL_THREAD_ATTACH )
{
if ( _pRawDllMain )
retcode = (*_pRawDllMain)(hDllHandle, dwReason, lpreserved);
if ( retcode )
retcode = _CRT_INIT(hDllHandle, dwReason, lpreserved);
if ( !retcode )
return FALSE;
}
retcode = DllMain(hDllHandle, dwReason, lpreserved);
if ( (dwReason == DLL_PROCESS_ATTACH) && !retcode )
/*
* The user's DllMain routine returned failure, the C runtime
* needs to be cleaned up. Do this by calling _CRT_INIT again,
* this time imitating DLL_PROCESS_DETACH. Note this will also
* clear the __proc_attached flag so the cleanup will not be
* repeated upon receiving the real process detach notification.
*/
_CRT_INIT(hDllHandle, DLL_PROCESS_DETACH, lpreserved);
if ( (dwReason == DLL_PROCESS_DETACH) ||
(dwReason == DLL_THREAD_DETACH) )
{
if ( _CRT_INIT(hDllHandle, dwReason, lpreserved) == FALSE )
retcode = FALSE ;
if ( retcode && _pRawDllMain )
retcode = (*_pRawDllMain)(hDllHandle, dwReason, lpreserved);
}
return retcode ;
}
#endif /* CRTDLL */