| |
| /* This code implemented by Dag.Gruneau@elsa.preseco.comm.se */ |
| /* Fast NonRecursiveMutex support by Yakov Markovitch, markovitch@iso.ru */ |
| /* Eliminated some memory leaks, gsw@agere.com */ |
| |
| #include <windows.h> |
| #include <limits.h> |
| #include <process.h> |
| |
| typedef struct NRMUTEX { |
| LONG owned ; |
| DWORD thread_id ; |
| HANDLE hevent ; |
| } NRMUTEX, *PNRMUTEX ; |
| |
| typedef PVOID WINAPI interlocked_cmp_xchg_t(PVOID *dest, PVOID exc, PVOID comperand) ; |
| |
| /* Sorry mate, but we haven't got InterlockedCompareExchange in Win95! */ |
| static PVOID WINAPI interlocked_cmp_xchg(PVOID *dest, PVOID exc, PVOID comperand) |
| { |
| static LONG spinlock = 0 ; |
| PVOID result ; |
| DWORD dwSleep = 0; |
| |
| /* Acqire spinlock (yielding control to other threads if cant aquire for the moment) */ |
| while(InterlockedExchange(&spinlock, 1)) |
| { |
| // Using Sleep(0) can cause a priority inversion. |
| // Sleep(0) only yields the processor if there's |
| // another thread of the same priority that's |
| // ready to run. If a high-priority thread is |
| // trying to acquire the lock, which is held by |
| // a low-priority thread, then the low-priority |
| // thread may never get scheduled and hence never |
| // free the lock. NT attempts to avoid priority |
| // inversions by temporarily boosting the priority |
| // of low-priority runnable threads, but the problem |
| // can still occur if there's a medium-priority |
| // thread that's always runnable. If Sleep(1) is used, |
| // then the thread unconditionally yields the CPU. We |
| // only do this for the second and subsequent even |
| // iterations, since a millisecond is a long time to wait |
| // if the thread can be scheduled in again sooner |
| // (~100,000 instructions). |
| // Avoid priority inversion: 0, 1, 0, 1,... |
| Sleep(dwSleep); |
| dwSleep = !dwSleep; |
| } |
| result = *dest ; |
| if (result == comperand) |
| *dest = exc ; |
| /* Release spinlock */ |
| spinlock = 0 ; |
| return result ; |
| } ; |
| |
| static interlocked_cmp_xchg_t *ixchg ; |
| BOOL InitializeNonRecursiveMutex(PNRMUTEX mutex) |
| { |
| if (!ixchg) |
| { |
| /* Sorely, Win95 has no InterlockedCompareExchange API (Win98 has), so we have to use emulation */ |
| HANDLE kernel = GetModuleHandle("kernel32.dll") ; |
| if (!kernel || (ixchg = (interlocked_cmp_xchg_t *)GetProcAddress(kernel, "InterlockedCompareExchange")) == NULL) |
| ixchg = interlocked_cmp_xchg ; |
| } |
| |
| mutex->owned = -1 ; /* No threads have entered NonRecursiveMutex */ |
| mutex->thread_id = 0 ; |
| mutex->hevent = CreateEvent(NULL, FALSE, FALSE, NULL) ; |
| return mutex->hevent != NULL ; /* TRUE if the mutex is created */ |
| } |
| |
| #ifdef InterlockedCompareExchange |
| #undef InterlockedCompareExchange |
| #endif |
| #define InterlockedCompareExchange(dest,exchange,comperand) (ixchg((dest), (exchange), (comperand))) |
| |
| VOID DeleteNonRecursiveMutex(PNRMUTEX mutex) |
| { |
| /* No in-use check */ |
| CloseHandle(mutex->hevent) ; |
| mutex->hevent = NULL ; /* Just in case */ |
| } |
| |
| DWORD EnterNonRecursiveMutex(PNRMUTEX mutex, BOOL wait) |
| { |
| /* Assume that the thread waits successfully */ |
| DWORD ret ; |
| |
| /* InterlockedIncrement(&mutex->owned) == 0 means that no thread currently owns the mutex */ |
| if (!wait) |
| { |
| if (InterlockedCompareExchange((PVOID *)&mutex->owned, (PVOID)0, (PVOID)-1) != (PVOID)-1) |
| return WAIT_TIMEOUT ; |
| ret = WAIT_OBJECT_0 ; |
| } |
| else |
| ret = InterlockedIncrement(&mutex->owned) ? |
| /* Some thread owns the mutex, let's wait... */ |
| WaitForSingleObject(mutex->hevent, INFINITE) : WAIT_OBJECT_0 ; |
| |
| mutex->thread_id = GetCurrentThreadId() ; /* We own it */ |
| return ret ; |
| } |
| |
| BOOL LeaveNonRecursiveMutex(PNRMUTEX mutex) |
| { |
| /* We don't own the mutex */ |
| mutex->thread_id = 0 ; |
| return |
| InterlockedDecrement(&mutex->owned) < 0 || |
| SetEvent(mutex->hevent) ; /* Other threads are waiting, wake one on them up */ |
| } |
| |
| PNRMUTEX AllocNonRecursiveMutex(void) |
| { |
| PNRMUTEX mutex = (PNRMUTEX)malloc(sizeof(NRMUTEX)) ; |
| if (mutex && !InitializeNonRecursiveMutex(mutex)) |
| { |
| free(mutex) ; |
| mutex = NULL ; |
| } |
| return mutex ; |
| } |
| |
| void FreeNonRecursiveMutex(PNRMUTEX mutex) |
| { |
| if (mutex) |
| { |
| DeleteNonRecursiveMutex(mutex) ; |
| free(mutex) ; |
| } |
| } |
| |
| long PyThread_get_thread_ident(void); |
| |
| /* |
| * Initialization of the C package, should not be needed. |
| */ |
| static void PyThread__init_thread(void) |
| { |
| } |
| |
| /* |
| * Thread support. |
| */ |
| |
| typedef struct { |
| void (*func)(void*); |
| void *arg; |
| long id; |
| HANDLE done; |
| } callobj; |
| |
| static int |
| bootstrap(void *call) |
| { |
| callobj *obj = (callobj*)call; |
| /* copy callobj since other thread might free it before we're done */ |
| void (*func)(void*) = obj->func; |
| void *arg = obj->arg; |
| |
| obj->id = PyThread_get_thread_ident(); |
| ReleaseSemaphore(obj->done, 1, NULL); |
| func(arg); |
| return 0; |
| } |
| |
| long |
| PyThread_start_new_thread(void (*func)(void *), void *arg) |
| { |
| uintptr_t rv; |
| callobj obj; |
| |
| dprintf(("%ld: PyThread_start_new_thread called\n", |
| PyThread_get_thread_ident())); |
| if (!initialized) |
| PyThread_init_thread(); |
| |
| obj.id = -1; /* guilty until proved innocent */ |
| obj.func = func; |
| obj.arg = arg; |
| obj.done = CreateSemaphore(NULL, 0, 1, NULL); |
| if (obj.done == NULL) |
| return -1; |
| |
| rv = _beginthread(bootstrap, 0, &obj); /* use default stack size */ |
| if (rv == (uintptr_t)-1) { |
| /* I've seen errno == EAGAIN here, which means "there are |
| * too many threads". |
| */ |
| dprintf(("%ld: PyThread_start_new_thread failed: %p errno %d\n", |
| PyThread_get_thread_ident(), rv, errno)); |
| obj.id = -1; |
| } |
| else { |
| dprintf(("%ld: PyThread_start_new_thread succeeded: %p\n", |
| PyThread_get_thread_ident(), rv)); |
| /* wait for thread to initialize, so we can get its id */ |
| WaitForSingleObject(obj.done, INFINITE); |
| assert(obj.id != -1); |
| } |
| CloseHandle((HANDLE)obj.done); |
| return obj.id; |
| } |
| |
| /* |
| * Return the thread Id instead of an handle. The Id is said to uniquely identify the |
| * thread in the system |
| */ |
| long PyThread_get_thread_ident(void) |
| { |
| if (!initialized) |
| PyThread_init_thread(); |
| |
| return GetCurrentThreadId(); |
| } |
| |
| static void do_PyThread_exit_thread(int no_cleanup) |
| { |
| dprintf(("%ld: PyThread_exit_thread called\n", PyThread_get_thread_ident())); |
| if (!initialized) |
| if (no_cleanup) |
| _exit(0); |
| else |
| exit(0); |
| _endthread(); |
| } |
| |
| void PyThread_exit_thread(void) |
| { |
| do_PyThread_exit_thread(0); |
| } |
| |
| void PyThread__exit_thread(void) |
| { |
| do_PyThread_exit_thread(1); |
| } |
| |
| #ifndef NO_EXIT_PROG |
| static void do_PyThread_exit_prog(int status, int no_cleanup) |
| { |
| dprintf(("PyThread_exit_prog(%d) called\n", status)); |
| if (!initialized) |
| if (no_cleanup) |
| _exit(status); |
| else |
| exit(status); |
| } |
| |
| void PyThread_exit_prog(int status) |
| { |
| do_PyThread_exit_prog(status, 0); |
| } |
| |
| void PyThread__exit_prog(int status) |
| { |
| do_PyThread_exit_prog(status, 1); |
| } |
| #endif /* NO_EXIT_PROG */ |
| |
| /* |
| * Lock support. It has too be implemented as semaphores. |
| * I [Dag] tried to implement it with mutex but I could find a way to |
| * tell whether a thread already own the lock or not. |
| */ |
| PyThread_type_lock PyThread_allocate_lock(void) |
| { |
| PNRMUTEX aLock; |
| |
| dprintf(("PyThread_allocate_lock called\n")); |
| if (!initialized) |
| PyThread_init_thread(); |
| |
| aLock = AllocNonRecursiveMutex() ; |
| |
| dprintf(("%ld: PyThread_allocate_lock() -> %p\n", PyThread_get_thread_ident(), aLock)); |
| |
| return (PyThread_type_lock) aLock; |
| } |
| |
| void PyThread_free_lock(PyThread_type_lock aLock) |
| { |
| dprintf(("%ld: PyThread_free_lock(%p) called\n", PyThread_get_thread_ident(),aLock)); |
| |
| FreeNonRecursiveMutex(aLock) ; |
| } |
| |
| /* |
| * Return 1 on success if the lock was acquired |
| * |
| * and 0 if the lock was not acquired. This means a 0 is returned |
| * if the lock has already been acquired by this thread! |
| */ |
| int PyThread_acquire_lock(PyThread_type_lock aLock, int waitflag) |
| { |
| int success ; |
| |
| dprintf(("%ld: PyThread_acquire_lock(%p, %d) called\n", PyThread_get_thread_ident(),aLock, waitflag)); |
| |
| success = aLock && EnterNonRecursiveMutex((PNRMUTEX) aLock, (waitflag ? INFINITE : 0)) == WAIT_OBJECT_0 ; |
| |
| dprintf(("%ld: PyThread_acquire_lock(%p, %d) -> %d\n", PyThread_get_thread_ident(),aLock, waitflag, success)); |
| |
| return success; |
| } |
| |
| void PyThread_release_lock(PyThread_type_lock aLock) |
| { |
| dprintf(("%ld: PyThread_release_lock(%p) called\n", PyThread_get_thread_ident(),aLock)); |
| |
| if (!(aLock && LeaveNonRecursiveMutex((PNRMUTEX) aLock))) |
| dprintf(("%ld: Could not PyThread_release_lock(%p) error: %l\n", PyThread_get_thread_ident(), aLock, GetLastError())); |
| } |