/* cygtls.cc Copyright 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014 Red Hat, Inc. 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 #include #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. */ 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