newlib-cygwin/winsup/mingw/dllcrt1.c

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/*
* dllcrt1.c
* This file has no copyright assigned and is placed in the Public Domain.
* This file is a part of the mingw-runtime package.
* No warranty is given; refer to the file DISCLAIMER within the package.
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*
* Initialization code for DLLs.
*
*/
#include <stdlib.h>
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#include <stdio.h>
#include <io.h>
#include <process.h>
#include <errno.h>
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#include <windows.h>
/* TLS initialization hook. */
extern const PIMAGE_TLS_CALLBACK __dyn_tls_init_callback;
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/* Unlike normal crt1, I don't initialize the FPU, because the process
* should have done that already. I also don't set the file handle modes,
* because that would be rude. */
#ifdef __GNUC__
extern void __main ();
extern void __do_global_dtors ();
#endif
typedef void (* p_atexit_fn )(void);
static p_atexit_fn* first_atexit;
static p_atexit_fn* next_atexit;
static void
__dll_exit (void);
/* This is based on the function in the Wine project's exit.c */
p_atexit_fn __dllonexit (p_atexit_fn, p_atexit_fn**, p_atexit_fn**);
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extern BOOL WINAPI DllMain (HANDLE, DWORD, LPVOID);
extern void _pei386_runtime_relocator (void);
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BOOL WINAPI
DllMainCRTStartup (HANDLE hDll, DWORD dwReason, LPVOID lpReserved)
{
BOOL bRet;
if (dwReason == DLL_PROCESS_ATTACH)
{
#ifdef DEBUG
printf ("%s: DLL_PROCESS_ATTACH (%d)\n", __FUNCTION__);
#endif
/* Initialize private atexit table for this dll.
32 is min size required by ANSI */
first_atexit = (p_atexit_fn*) malloc (32 * sizeof (p_atexit_fn));
if (first_atexit == NULL ) /* can't allocate memory */
{
errno=ENOMEM;
return FALSE;
}
*first_atexit = NULL;
next_atexit = first_atexit;
/* Initialize TLS callback. */
if (__dyn_tls_init_callback != NULL)
{
__dyn_tls_init_callback (hDll, DLL_THREAD_ATTACH, lpReserved);
}
/* Adust references to dllimported data (from other DLL's)
that have non-zero offsets. */
_pei386_runtime_relocator ();
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#ifdef __GNUC__
/* From libgcc.a, __main calls global class constructors,
__do_global_ctors, which registers __do_global_dtors
as the first entry of the private atexit table we
have just initialised */
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__main ();
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#endif
}
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/*
* Call the user-supplied DllMain subroutine.
* This has to come after initialization of atexit table and
* registration of global constructors.
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* NOTE: DllMain is optional, so libmingw32.a includes a stub
* which will be used if the user does not supply one.
*/
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bRet = DllMain (hDll, dwReason, lpReserved);
/* Handle case where DllMain returns FALSE on attachment attempt. */
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if ( (dwReason == DLL_PROCESS_ATTACH) && !bRet)
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{
#ifdef DEBUG
printf ("%s: DLL_PROCESS_ATTACH failed, cleaning up\n", __FUNCTION__);
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#endif
__dll_exit (); /* Cleanup now. This will set first_atexit to NULL so we
know we've cleaned up */
}
if (dwReason == DLL_PROCESS_DETACH)
{
#ifdef DEBUG
printf ("%s: DLL_PROCESS_DETACH (%d)\n", __FUNCTION__);
#endif
/* If not attached, return FALSE. Cleanup already done above
if failed attachment attempt. */
if (! first_atexit )
bRet = FALSE;
else
/*
* We used to call __do_global_dtors () here. This is
* no longer necessary since __do_global_dtors is now
* registered at start (last out) of private atexit table.
*/
__dll_exit ();
}
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return bRet;
}
static
void
__dll_exit(void)
/* Run LIFO terminators registered in private atexit table */
{
if ( first_atexit )
{
p_atexit_fn* __last = next_atexit - 1;
while ( __last >= first_atexit )
{
if ( *__last != NULL )
{
#ifdef DEBUG
printf ("%s: Calling exit function 0x%x from 0x%x\n",
__FUNCTION__, (unsigned)(*__last),(unsigned)__last);
#endif
(**__last) ();
}
__last--;
}
free ( first_atexit ) ;
first_atexit = NULL ;
}
/*
Make sure output buffers opened by DllMain or
atexit-registered functions are flushed before detaching,
otherwise we can have problems with redirected output.
*/
fflush (NULL);
}
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/*
* The atexit exported from msvcrt.dll causes problems in DLLs.
* Here, we override the exported version of atexit with one that passes the
* private table initialised in DllMainCRTStartup to __dllonexit.
* That means we have to hide the mscvrt.dll atexit because the
* atexit defined here gets __dllonexit from the same lib.
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*/
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int
atexit (p_atexit_fn pfn )
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{
#ifdef DEBUG
printf ("%s: registering exit function 0x%x at 0x%x\n",
__FUNCTION__, (unsigned)pfn, (unsigned)next_atexit);
#endif
return (__dllonexit (pfn, &first_atexit, &next_atexit)
== NULL ? -1 : 0 );
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}
/*
* Likewise for non-ANSI function _onexit that may be called by
* code in the dll.
*/
_onexit_t
_onexit (_onexit_t pfn )
{
#ifdef DEBUG
printf ("%s: registering exit function 0x%x at 0x%x\n",
__FUNCTION__, (unsigned)pfn, (unsigned)next_atexit);
#endif
return ((_onexit_t) __dllonexit ((p_atexit_fn)pfn, &first_atexit, &next_atexit));
}