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/* init.cc
This file is part of Cygwin.
This software is a copyrighted work licensed under the terms of the
Cygwin license. Please consult the file "CYGWIN_LICENSE" for
details. */
#include "winsup.h"
#include "cygtls.h"
#include "ntdll.h"
#include "shared_info.h"
static DWORD _my_oldfunc;
static char *search_for = (char *) cygthread::stub;
unsigned threadfunc_ix[8];
static bool dll_finished_loading;
#define OLDFUNC_OFFSET -1
static void WINAPI
threadfunc_fe (VOID *arg)
{
#ifdef __i386__
#if __GNUC_PREREQ(6,0)
#pragma GCC diagnostic ignored "-Wframe-address"
#endif
(void)__builtin_return_address(1);
#if __GNUC_PREREQ(6,0)
#pragma GCC diagnostic pop
#endif
asm volatile ("andl $-16,%%esp" ::: "%esp");
#endif
_cygtls::call ((DWORD (*) (void *, void *)) TlsGetValue (_my_oldfunc), arg);
}
/* If possible, redirect the thread entry point to a cygwin routine which
adds tls stuff to the stack. */
static void
munge_threadfunc ()
{
int i;
char **ebp = (char **) __builtin_frame_address (0);
if (!threadfunc_ix[0])
{
char **peb;
char **top = (char **) NtCurrentTeb()->Tib.StackBase;
for (peb = ebp, i = 0; peb < top && i < 7; peb++)
if (*peb == search_for)
threadfunc_ix[i++] = peb - ebp;
if (0 && !threadfunc_ix[0])
{
try_to_debug ();
return;
}
}
if (threadfunc_ix[0])
{
char *threadfunc = NULL;
NtQueryInformationThread (NtCurrentThread (),
ThreadQuerySetWin32StartAddress,
&threadfunc, sizeof threadfunc, NULL);
if (!search_for || threadfunc == search_for)
{
search_for = NULL;
for (i = 0; threadfunc_ix[i]; i++)
if (!threadfunc || ebp[threadfunc_ix[i]] == threadfunc)
ebp[threadfunc_ix[i]] = (char *) threadfunc_fe;
TlsSetValue (_my_oldfunc, threadfunc);
}
}
}
void dll_crt0_0 ();
/* Non-static fake variable so GCC doesn't second-guess if we *really*
need the alloca'd space in the DLL_PROCESS_ATTACH case below... */
void *alloca_dummy;
extern "C" BOOL WINAPI
dll_entry (HANDLE h, DWORD reason, void *static_load)
{
BOOL test_stack_marker;
switch (reason)
{
case DLL_PROCESS_ATTACH:
init_console_handler (false);
cygwin_hmodule = (HMODULE) h;
dynamically_loaded = (static_load == NULL);
/* Starting with adding the POSIX-1.2008 per-thread locale functionality,
we need an initalized _REENT area even for the functions called from
dll_crt0_0. Most importantly, we need the _REENT->_locale pointer
initialized to NULL, so subsequent calls to locale-specific functions
will always fall back to __global_locale, rather then crash due to
_REENT->_locale having an arbitrary value. */
alloca_dummy = alloca (CYGTLS_PADSIZE);
ZeroMemory (alloca_dummy, CYGTLS_PADSIZE);
memcpy (_REENT, _GLOBAL_REENT, sizeof (struct _reent));
dll_crt0_0 ();
_my_oldfunc = TlsAlloc ();
dll_finished_loading = true;
break;
case DLL_PROCESS_DETACH:
if (dynamically_loaded)
shared_destroy ();
break;
case DLL_THREAD_ATTACH:
if (dll_finished_loading)
munge_threadfunc ();
break;
case DLL_THREAD_DETACH:
if (dll_finished_loading
&& (PVOID) &_my_tls > (PVOID) &test_stack_marker
&& _my_tls.isinitialized ())
_my_tls.remove (0);
break;
}
return TRUE;
}
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