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/* cygtls.cc
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"
#define USE_SYS_TYPES_FD_SET
#include "cygtls.h"
#include <syslog.h>
#include <stdlib.h>
#include "path.h"
#include "fhandler.h"
#include "dtable.h"
#include "cygheap.h"
#include "sigproc.h"
#include "exception.h"
/* Two calls to get the stack right... */
void
_cygtls::call (DWORD (*func) (void *, void *), void *arg)
{
char buf[CYGTLS_PADSIZE];
/* Initialize this thread's ability to respond to things like
SIGSEGV or SIGFPE. */
exception protect;
_my_tls.call2 (func, arg, buf);
}
static int
dll_cmp (const void *a, const void *b)
{
return wcscasecmp ((const wchar_t *) a, *(const wchar_t **) b);
}
/* Keep sorted!
This is a list of well-known core system DLLs which contain code
started in its own thread by the system. Kernel32.dll, for instance,
contains the thread called on every Ctrl-C keypress in a console window.
The DLLs in this list are not recognized as BLODAs. */
const wchar_t *well_known_dlls[] =
{
L"advapi32.dll",
L"kernel32.dll",
L"kernelbase.dll",
L"mswsock.dll",
L"ntdll.dll",
L"ole32.dll",
L"shlwapi.dll",
L"wbemprox.dll",
L"ws2_32.dll",
};
/* Optional BLODA detection. The idea is that the function address is supposed
to be within Cygwin itself. This is also true for pthreads, since pthreads
are always calling pthread::thread_init_wrapper() in thread.cc. Therefore,
every function call to a function outside of the Cygwin DLL is potentially
a thread injected into the Cygwin process by some BLODA.
But that's too simple. Assuming the application itself calls CreateThread,
then this is a bad idea, but not really invalid. So we shouldn't print a
BLODA message if the address is within the loaded image of the application.
Also, ntdll.dll starts threads into the application which */
static void
bloda_detect (DWORD (*func) (void *, void *))
{
PIMAGE_DOS_HEADER img_start = (PIMAGE_DOS_HEADER)
GetModuleHandle (NULL);
PIMAGE_NT_HEADERS32 ntheader = (PIMAGE_NT_HEADERS32)
((PBYTE) img_start + img_start->e_lfanew);
void *img_end = (void *) ((PBYTE) img_start
+ ntheader->OptionalHeader.SizeOfImage);
if (((void *) func < (void *) cygwin_hmodule
|| (void *) func > (void *) cygheap)
&& ((void *) func < (void *) img_start || (void *) func >= img_end))
{
MEMORY_BASIC_INFORMATION mbi;
wchar_t modname[PATH_MAX];
VirtualQuery ((PVOID) func, &mbi, sizeof mbi);
GetModuleFileNameW ((HMODULE) mbi.AllocationBase, modname,
PATH_MAX);
/* Fetch basename and check against list of above system DLLs. */
const wchar_t *modbasename = wcsrchr (modname, L'\\') + 1;
if (!bsearch (modbasename, well_known_dlls,
sizeof well_known_dlls / sizeof well_known_dlls[0],
sizeof well_known_dlls[0], dll_cmp))
small_printf ("\n\nPotential BLODA detected! Thread function "
"called outside of Cygwin DLL:\n %W\n\n",
modname);
}
}
void
_cygtls::call2 (DWORD (*func) (void *, void *), void *arg, void *buf)
{
/* If func is pthread_wrapper, the final stack hasn't been set up yet.
This only happens in pthread_wrapper itself. Thus it doesn't make
sense to call init_thread or perform BLODA detection. pthread_wrapper
eventually calls init_thread by itself. */
if ((void *) func != (void *) pthread_wrapper)
{
init_thread (buf, func);
if (detect_bloda)
bloda_detect (func);
}
DWORD res = func (arg, buf);
remove (INFINITE);
/* Don't call ExitThread on the main thread since we may have been
dynamically loaded. */
if ((void *) func != (void *) dll_crt0_1
&& (void *) func != (void *) dll_dllcrt0_1)
ExitThread (res);
}
void
_cygtls::init_thread (void *x, DWORD (*func) (void *, void *))
{
if (x)
{
memset (this, 0, sizeof (*this));
_REENT_INIT_PTR (&local_clib);
stackptr = stack;
altstack.ss_flags = SS_DISABLE;
if (_GLOBAL_REENT)
{
local_clib._stdin = _GLOBAL_REENT->_stdin;
local_clib._stdout = _GLOBAL_REENT->_stdout;
local_clib._stderr = _GLOBAL_REENT->_stderr;
local_clib.__sdidinit = _GLOBAL_REENT->__sdidinit ? -1 : 0;
local_clib.__cleanup = _GLOBAL_REENT->__cleanup;
local_clib.__sglue._niobs = 3;
local_clib.__sglue._iobs = &_GLOBAL_REENT->__sf[0];
}
}
thread_id = GetCurrentThreadId ();
initialized = CYGTLS_INITIALIZED;
errno_addr = &(local_clib._errno);
locals.cw_timer = NULL;
if ((void *) func == (void *) cygthread::stub
|| (void *) func == (void *) cygthread::simplestub)
return;
cygheap->add_tls (this);
}
void
_cygtls::fixup_after_fork ()
{
if (sig)
{
pop ();
sig = 0;
}
stacklock = spinning = 0;
signal_arrived = NULL;
locals.select.sockevt = NULL;
locals.cw_timer = NULL;
wq.thread_ev = NULL;
}
#define free_local(x) \
if (locals.x) \
{ \
free (locals.x); \
locals.x = NULL; \
}
void
_cygtls::remove (DWORD wait)
{
initialized = 0;
if (exit_state >= ES_FINAL)
return;
debug_printf ("wait %u", wait);
HANDLE mutex = cygheap->remove_tls (this);
remove_wq (wait);
/* FIXME: Need some sort of atthreadexit function to allow things like
select to control this themselves. */
remove_pending_sigs ();
if (signal_arrived)
{
HANDLE h = signal_arrived;
signal_arrived = NULL;
CloseHandle (h);
}
/* Close handle and free memory used by select. */
if (locals.select.sockevt)
{
CloseHandle (locals.select.sockevt);
locals.select.sockevt = NULL;
free_local (select.ser_num);
free_local (select.w4);
}
/* Free memory used by network functions. */
free_local (ntoa_buf);
free_local (protoent_buf);
free_local (servent_buf);
free_local (hostent_buf);
/* Free temporary TLS path buffers. */
locals.pathbufs.destroy ();
/* Close timer handle. */
if (locals.cw_timer)
NtClose (locals.cw_timer);
if (mutex)
{
ReleaseMutex (mutex);
CloseHandle (mutex);
}
}
#ifdef __x86_64__
void san::leave ()
{
/* Restore tls_pathbuf counters in case of error. */
_my_tls.locals.pathbufs._counters = _cnt;
_my_tls.andreas = _clemente;
}
#endif
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