/* Thread module */

/* Interface to Sjoerd's portable C thread library */

#include "Python.h"

#include "pycore_fileutils.h" // _PyFile_Flush

#include "pycore_interp.h" // _PyInterpreterState.threads.count

#include "pycore_lock.h"

#include "pycore_modsupport.h" // _PyArg_NoKeywords()

#include "pycore_moduleobject.h" // _PyModule_GetState()

#include "pycore_object_deferred.h" // _PyObject_SetDeferredRefcount()

#include "pycore_pylifecycle.h"

#include "pycore_pystate.h" // _PyThreadState_SetCurrent()

#include "pycore_sysmodule.h" // _PySys_GetOptionalAttr()

#include "pycore_time.h" // _PyTime_FromSeconds()

#include "pycore_weakref.h" // _PyWeakref_GET_REF()

#include <stddef.h> // offsetof()

#ifdef HAVE_SIGNAL_H

# include <signal.h> // SIGINT

#endif

// ThreadError is just an alias to PyExc_RuntimeError

#define ThreadError PyExc_RuntimeError

// Forward declarations

static struct PyModuleDef thread_module;

// Module state

typedef struct {

PyTypeObject *excepthook_type;

PyTypeObject *lock_type;

PyTypeObject *rlock_type;

PyTypeObject *local_type;

PyTypeObject *local_dummy_type;

PyTypeObject *thread_handle_type;

// Linked list of handles to all non-daemon threads created by the

// threading module. We wait for these to finish at shutdown.

struct llist_node shutdown_handles;

} thread_module_state;

static inline thread_module_state*

get_thread_state(PyObject *module)

{

void *state = _PyModule_GetState(module);

assert(state != NULL);

return (thread_module_state *)state;

}

static inline thread_module_state*

get_thread_state_by_cls(PyTypeObject *cls)

{

// Use PyType_GetModuleByDef() to handle (R)Lock subclasses.

PyObject *module = PyType_GetModuleByDef(cls, &thread_module);

if (module == NULL) {

return NULL;

}

return get_thread_state(module);

}

#ifdef MS_WINDOWS

typedef HRESULT (WINAPI *PF_GET_THREAD_DESCRIPTION)(HANDLE, PCWSTR*);

typedef HRESULT (WINAPI *PF_SET_THREAD_DESCRIPTION)(HANDLE, PCWSTR);

static PF_GET_THREAD_DESCRIPTION pGetThreadDescription = NULL;

static PF_SET_THREAD_DESCRIPTION pSetThreadDescription = NULL;

#endif

/*[clinic input]

module _thread

class _thread.lock "lockobject *" "clinic_state()->lock_type"

class _thread.RLock "rlockobject *" "clinic_state()->rlock_type"

[clinic start generated code]*/

/*[clinic end generated code: output=da39a3ee5e6b4b0d input=c5a0f8c492a0c263]*/

#define clinic_state() get_thread_state_by_cls(type)

#include "clinic/_threadmodule.c.h"

#undef clinic_state

// _ThreadHandle type

// Handles state transitions according to the following diagram:

//

// NOT_STARTED -> STARTING -> RUNNING -> DONE

// | ^

// | |

// +----- error --------+

typedef enum {

THREAD_HANDLE_NOT_STARTED = 1,

THREAD_HANDLE_STARTING = 2,

THREAD_HANDLE_RUNNING = 3,

THREAD_HANDLE_DONE = 4,

} ThreadHandleState;

// A handle to wait for thread completion.

//

// This may be used to wait for threads that were spawned by the threading

// module as well as for the "main" thread of the threading module. In the

// former case an OS thread, identified by the `os_handle` field, will be

// associated with the handle. The handle "owns" this thread and ensures that

// the thread is either joined or detached after the handle is destroyed.

//

// Joining the handle is idempotent; the underlying OS thread, if any, is

// joined or detached only once. Concurrent join operations are serialized

// until it is their turn to execute or an earlier operation completes

// successfully. Once a join has completed successfully all future joins

// complete immediately.

//

// This must be separately reference counted because it may be destroyed

// in `thread_run()` after the PyThreadState has been destroyed.

typedef struct {

struct llist_node node; // linked list node (see _pythread_runtime_state)

// linked list node (see thread_module_state)

struct llist_node shutdown_node;

// The `ident`, `os_handle`, `has_os_handle`, and `state` fields are

// protected by `mutex`.

PyThread_ident_t ident;

PyThread_handle_t os_handle;

int has_os_handle;

// Holds a value from the `ThreadHandleState` enum.

int state;

PyMutex mutex;

// Set immediately before `thread_run` returns to indicate that the OS

// thread is about to exit. This is used to avoid false positives when

// detecting self-join attempts. See the comment in `ThreadHandle_join()`

// for a more detailed explanation.

PyEvent thread_is_exiting;

// Serializes calls to `join` and `set_done`.

_PyOnceFlag once;

Py_ssize_t refcount;

} ThreadHandle;

static inline int

get_thread_handle_state(ThreadHandle *handle)

{

PyMutex_Lock(&handle->mutex);

int state = handle->state;

PyMutex_Unlock(&handle->mutex);

return state;

}

static inline void

set_thread_handle_state(ThreadHandle *handle, ThreadHandleState state)

{

PyMutex_Lock(&handle->mutex);

handle->state = state;

PyMutex_Unlock(&handle->mutex);

}

static PyThread_ident_t

ThreadHandle_ident(ThreadHandle *handle)

{

PyMutex_Lock(&handle->mutex);

PyThread_ident_t ident = handle->ident;

PyMutex_Unlock(&handle->mutex);

return ident;

}

static int

ThreadHandle_get_os_handle(ThreadHandle *handle, PyThread_handle_t *os_handle)

{

PyMutex_Lock(&handle->mutex);

int has_os_handle = handle->has_os_handle;

if (has_os_handle) {

*os_handle = handle->os_handle;

}

PyMutex_Unlock(&handle->mutex);

return has_os_handle;

}

static void

add_to_shutdown_handles(thread_module_state *state, ThreadHandle *handle)

{

HEAD_LOCK(&_PyRuntime);

llist_insert_tail(&state->shutdown_handles, &handle->shutdown_node);

HEAD_UNLOCK(&_PyRuntime);

}

static void

clear_shutdown_handles(thread_module_state *state)

{

HEAD_LOCK(&_PyRuntime);

struct llist_node *node;

llist_for_each_safe(node, &state->shutdown_handles) {

llist_remove(node);

}

HEAD_UNLOCK(&_PyRuntime);

}

static void

remove_from_shutdown_handles(ThreadHandle *handle)

{

HEAD_LOCK(&_PyRuntime);

if (handle->shutdown_node.next != NULL) {

llist_remove(&handle->shutdown_node);

}

HEAD_UNLOCK(&_PyRuntime);

}

static ThreadHandle *

ThreadHandle_new(void)

{

ThreadHandle *self =

(ThreadHandle *)PyMem_RawCalloc(1, sizeof(ThreadHandle));

if (self == NULL) {

PyErr_NoMemory();

return NULL;

}

self->ident = 0;

self->os_handle = 0;

self->has_os_handle = 0;

self->thread_is_exiting = (PyEvent){0};

self->mutex = (PyMutex){_Py_UNLOCKED};

self->once = (_PyOnceFlag){0};

self->state = THREAD_HANDLE_NOT_STARTED;

self->refcount = 1;

HEAD_LOCK(&_PyRuntime);

llist_insert_tail(&_PyRuntime.threads.handles, &self->node);

HEAD_UNLOCK(&_PyRuntime);

return self;

}

static void

ThreadHandle_incref(ThreadHandle *self)

{

_Py_atomic_add_ssize(&self->refcount, 1);

}

static int

detach_thread(ThreadHandle *self)

{

if (!self->has_os_handle) {

return 0;

}

// This is typically short so no need to release the GIL

if (PyThread_detach_thread(self->os_handle)) {

fprintf(stderr, "detach_thread: failed detaching thread\n");

return -1;

}

return 0;

}

// NB: This may be called after the PyThreadState in `thread_run` has been

// deleted; it cannot call anything that relies on a valid PyThreadState

// existing.

static void

ThreadHandle_decref(ThreadHandle *self)

{

if (_Py_atomic_add_ssize(&self->refcount, -1) > 1) {

return;

}

// Remove ourself from the global list of handles

HEAD_LOCK(&_PyRuntime);

if (self->node.next != NULL) {

llist_remove(&self->node);

}

HEAD_UNLOCK(&_PyRuntime);

assert(self->shutdown_node.next == NULL);

// It's safe to access state non-atomically:

// 1. This is the destructor; nothing else holds a reference.

// 2. The refcount going to zero is a "synchronizes-with" event; all

// changes from other threads are visible.

if (self->state == THREAD_HANDLE_RUNNING && !detach_thread(self)) {

self->state = THREAD_HANDLE_DONE;

}

PyMem_RawFree(self);

}

void

_PyThread_AfterFork(struct _pythread_runtime_state *state)

{

// gh-115035: We mark ThreadHandles as not joinable early in the child's

// after-fork handler. We do this before calling any Python code to ensure

// that it happens before any ThreadHandles are deallocated, such as by a

// GC cycle.

PyThread_ident_t current = PyThread_get_thread_ident_ex();

struct llist_node *node;

llist_for_each_safe(node, &state->handles) {

ThreadHandle *handle = llist_data(node, ThreadHandle, node);

if (handle->ident == current) {

continue;

}

// Mark all threads as done. Any attempts to join or detach the

// underlying OS thread (if any) could crash. We are the only thread;

// it's safe to set this non-atomically.

handle->state = THREAD_HANDLE_DONE;

handle->once = (_PyOnceFlag){_Py_ONCE_INITIALIZED};

handle->mutex = (PyMutex){_Py_UNLOCKED};

_PyEvent_Notify(&handle->thread_is_exiting);

llist_remove(node);

remove_from_shutdown_handles(handle);

}

}

// bootstate is used to "bootstrap" new threads. Any arguments needed by

// `thread_run()`, which can only take a single argument due to platform

// limitations, are contained in bootstate.

struct bootstate {

PyThreadState *tstate;

PyObject *func;

PyObject *args;

PyObject *kwargs;

ThreadHandle *handle;

PyEvent handle_ready;

};

static void

thread_bootstate_free(struct bootstate *boot, int decref)

{

if (decref) {

Py_DECREF(boot->func);

Py_DECREF(boot->args);

Py_XDECREF(boot->kwargs);

}

ThreadHandle_decref(boot->handle);

PyMem_RawFree(boot);

}

static void

thread_run(void *boot_raw)

{

struct bootstate *boot = (struct bootstate *) boot_raw;

PyThreadState *tstate = boot->tstate;

// Wait until the handle is marked as running

PyEvent_Wait(&boot->handle_ready);

// `handle` needs to be manipulated after bootstate has been freed

ThreadHandle *handle = boot->handle;

ThreadHandle_incref(handle);

// gh-108987: If _thread.start_new_thread() is called before or while

// Python is being finalized, thread_run() can called *after*.

// _PyRuntimeState_SetFinalizing() is called. At this point, all Python

// threads must exit, except of the thread calling Py_Finalize() which

// holds the GIL and must not exit.

if (_PyThreadState_MustExit(tstate)) {

// Don't call PyThreadState_Clear() nor _PyThreadState_DeleteCurrent().

// These functions are called on tstate indirectly by Py_Finalize()

// which calls _PyInterpreterState_Clear().

//

// Py_DECREF() cannot be called because the GIL is not held: leak

// references on purpose. Python is being finalized anyway.

thread_bootstate_free(boot, 0);

goto exit;

}

_PyThreadState_Bind(tstate);

PyEval_AcquireThread(tstate);

_Py_atomic_add_ssize(&tstate->interp->threads.count, 1);

PyObject *res = PyObject_Call(boot->func, boot->args, boot->kwargs);

if (res == NULL) {

if (PyErr_ExceptionMatches(PyExc_SystemExit))

/* SystemExit is ignored silently */

PyErr_Clear();

else {

PyErr_FormatUnraisable(

"Exception ignored in thread started by %R", boot->func);

}

}

else {

Py_DECREF(res);

}

thread_bootstate_free(boot, 1);

_Py_atomic_add_ssize(&tstate->interp->threads.count, -1);

PyThreadState_Clear(tstate);

_PyThreadState_DeleteCurrent(tstate);

exit:

// Don't need to wait for this thread anymore

remove_from_shutdown_handles(handle);

_PyEvent_Notify(&handle->thread_is_exiting);

ThreadHandle_decref(handle);

// bpo-44434: Don't call explicitly PyThread_exit_thread(). On Linux with

// the glibc, pthread_exit() can abort the whole process if dlopen() fails

// to open the libgcc_s.so library (ex: EMFILE error).

return;

}

static int

force_done(void *arg)

{

ThreadHandle *handle = (ThreadHandle *)arg;

assert(get_thread_handle_state(handle) == THREAD_HANDLE_STARTING);

_PyEvent_Notify(&handle->thread_is_exiting);

set_thread_handle_state(handle, THREAD_HANDLE_DONE);

return 0;

}

static int

ThreadHandle_start(ThreadHandle *self, PyObject *func, PyObject *args,

PyObject *kwargs)

{

// Mark the handle as starting to prevent any other threads from doing so

PyMutex_Lock(&self->mutex);

if (self->state != THREAD_HANDLE_NOT_STARTED) {

PyMutex_Unlock(&self->mutex);

PyErr_SetString(ThreadError, "thread already started");

return -1;

}

self->state = THREAD_HANDLE_STARTING;

PyMutex_Unlock(&self->mutex);

// Do all the heavy lifting outside of the mutex. All other operations on

// the handle should fail since the handle is in the starting state.

// gh-109795: Use PyMem_RawMalloc() instead of PyMem_Malloc(),

// because it should be possible to call thread_bootstate_free()

// without holding the GIL.

struct bootstate *boot = PyMem_RawMalloc(sizeof(struct bootstate));

if (boot == NULL) {

PyErr_NoMemory();

goto start_failed;

}

PyInterpreterState *interp = _PyInterpreterState_GET();

boot->tstate = _PyThreadState_New(interp, _PyThreadState_WHENCE_THREADING);

if (boot->tstate == NULL) {

PyMem_RawFree(boot);

if (!PyErr_Occurred()) {

PyErr_NoMemory();

}

goto start_failed;

}

boot->func = Py_NewRef(func);

boot->args = Py_NewRef(args);

boot->kwargs = Py_XNewRef(kwargs);

boot->handle = self;

ThreadHandle_incref(self);

boot->handle_ready = (PyEvent){0};

PyThread_ident_t ident;

PyThread_handle_t os_handle;

if (PyThread_start_joinable_thread(thread_run, boot, &ident, &os_handle)) {

PyThreadState_Clear(boot->tstate);

PyThreadState_Delete(boot->tstate);

thread_bootstate_free(boot, 1);

PyErr_SetString(ThreadError, "can't start new thread");

goto start_failed;

}

// Mark the handle running

PyMutex_Lock(&self->mutex);

assert(self->state == THREAD_HANDLE_STARTING);

self->ident = ident;

self->has_os_handle = 1;

self->os_handle = os_handle;

self->state = THREAD_HANDLE_RUNNING;

PyMutex_Unlock(&self->mutex);

// Unblock the thread

_PyEvent_Notify(&boot->handle_ready);

return 0;

start_failed:

_PyOnceFlag_CallOnce(&self->once, force_done, self);

return -1;

}

static int

join_thread(void *arg)

{

ThreadHandle *handle = (ThreadHandle*)arg;

assert(get_thread_handle_state(handle) == THREAD_HANDLE_RUNNING);

PyThread_handle_t os_handle;

if (ThreadHandle_get_os_handle(handle, &os_handle)) {

int err = 0;

Py_BEGIN_ALLOW_THREADS

err = PyThread_join_thread(os_handle);

Py_END_ALLOW_THREADS

if (err) {

PyErr_SetString(ThreadError, "Failed joining thread");

return -1;

}

}

set_thread_handle_state(handle, THREAD_HANDLE_DONE);

return 0;

}

static int

check_started(ThreadHandle *self)

{

ThreadHandleState state = get_thread_handle_state(self);

if (state < THREAD_HANDLE_RUNNING) {

PyErr_SetString(ThreadError, "thread not started");

return -1;

}

return 0;

}

static int

ThreadHandle_join(ThreadHandle *self, PyTime_t timeout_ns)

{

if (check_started(self) < 0) {

return -1;

}

// We want to perform this check outside of the `_PyOnceFlag` to prevent

// deadlock in the scenario where another thread joins us and we then

// attempt to join ourselves. However, it's not safe to check thread

// identity once the handle's os thread has finished. We may end up reusing

// the identity stored in the handle and erroneously think we are

// attempting to join ourselves.

//

// To work around this, we set `thread_is_exiting` immediately before

// `thread_run` returns. We can be sure that we are not attempting to join

// ourselves if the handle's thread is about to exit.

if (!_PyEvent_IsSet(&self->thread_is_exiting)) {

if (ThreadHandle_ident(self) == PyThread_get_thread_ident_ex()) {

// PyThread_join_thread() would deadlock or error out.

PyErr_SetString(ThreadError, "Cannot join current thread");

return -1;

}

if (Py_IsFinalizing()) {

// gh-123940: On finalization, other threads are prevented from

// running Python code. They cannot finalize themselves,

// so join() would hang forever (or until timeout).

// We raise instead.

PyErr_SetString(PyExc_PythonFinalizationError,

"cannot join thread at interpreter shutdown");

return -1;

}

}

// Wait until the deadline for the thread to exit.

PyTime_t deadline = timeout_ns != -1 ? _PyDeadline_Init(timeout_ns) : 0;

int detach = 1;

while (!PyEvent_WaitTimed(&self->thread_is_exiting, timeout_ns, detach)) {

if (deadline) {

// _PyDeadline_Get will return a negative value if the deadline has

// been exceeded.

timeout_ns = Py_MAX(_PyDeadline_Get(deadline), 0);

}

if (timeout_ns) {

// Interrupted

if (Py_MakePendingCalls() < 0) {

return -1;

}

}

else {

// Timed out

return 0;

}

}

if (_PyOnceFlag_CallOnce(&self->once, join_thread, self) == -1) {

return -1;

}

assert(get_thread_handle_state(self) == THREAD_HANDLE_DONE);

return 0;

}

static int

set_done(void *arg)

{

ThreadHandle *handle = (ThreadHandle*)arg;

assert(get_thread_handle_state(handle) == THREAD_HANDLE_RUNNING);

if (detach_thread(handle) < 0) {

PyErr_SetString(ThreadError, "failed detaching handle");

return -1;

}

_PyEvent_Notify(&handle->thread_is_exiting);

set_thread_handle_state(handle, THREAD_HANDLE_DONE);

return 0;

}

static int

ThreadHandle_set_done(ThreadHandle *self)

{

if (check_started(self) < 0) {

return -1;

}

if (_PyOnceFlag_CallOnce(&self->once, set_done, self) ==

-1) {

return -1;

}

assert(get_thread_handle_state(self) == THREAD_HANDLE_DONE);

return 0;

}

// A wrapper around a ThreadHandle.

typedef struct {

PyObject_HEAD

ThreadHandle *handle;

} PyThreadHandleObject;

#define PyThreadHandleObject_CAST(op) ((PyThreadHandleObject *)(op))

static PyThreadHandleObject *

PyThreadHandleObject_new(PyTypeObject *type)

{

ThreadHandle *handle = ThreadHandle_new();

if (handle == NULL) {

return NULL;

}

PyThreadHandleObject *self =

(PyThreadHandleObject *)type->tp_alloc(type, 0);

if (self == NULL) {

ThreadHandle_decref(handle);

return NULL;

}

self->handle = handle;

return self;

}

static PyObject *

PyThreadHandleObject_tp_new(PyTypeObject *type, PyObject *args, PyObject *kwds)

{

return (PyObject *)PyThreadHandleObject_new(type);

}

static int

PyThreadHandleObject_traverse(PyObject *self, visitproc visit, void *arg)

{

Py_VISIT(Py_TYPE(self));

return 0;

}

static void

PyThreadHandleObject_dealloc(PyObject *op)

{

PyThreadHandleObject *self = PyThreadHandleObject_CAST(op);

PyObject_GC_UnTrack(self);

PyTypeObject *tp = Py_TYPE(self);

ThreadHandle_decref(self->handle);

tp->tp_free(self);

Py_DECREF(tp);

}

static PyObject *

PyThreadHandleObject_repr(PyObject *op)

{

PyThreadHandleObject *self = PyThreadHandleObject_CAST(op);

PyThread_ident_t ident = ThreadHandle_ident(self->handle);

return PyUnicode_FromFormat("<%s object: ident=%" PY_FORMAT_THREAD_IDENT_T ">",

Py_TYPE(self)->tp_name, ident);

}

static PyObject *

PyThreadHandleObject_get_ident(PyObject *op, void *Py_UNUSED(closure))

{

PyThreadHandleObject *self = PyThreadHandleObject_CAST(op);

return PyLong_FromUnsignedLongLong(ThreadHandle_ident(self->handle));

}

static PyObject *

PyThreadHandleObject_join(PyObject *op, PyObject *args)

{

PyThreadHandleObject *self = PyThreadHandleObject_CAST(op);

PyObject *timeout_obj = NULL;

if (!PyArg_ParseTuple(args, "|O?:join", &timeout_obj)) {

return NULL;

}

PyTime_t timeout_ns = -1;

if (timeout_obj != NULL) {

if (_PyTime_FromSecondsObject(&timeout_ns, timeout_obj,

_PyTime_ROUND_TIMEOUT) < 0) {

return NULL;

}

}

if (ThreadHandle_join(self->handle, timeout_ns) < 0) {

return NULL;

}

Py_RETURN_NONE;

}

static PyObject *

PyThreadHandleObject_is_done(PyObject *op, PyObject *Py_UNUSED(dummy))

{

PyThreadHandleObject *self = PyThreadHandleObject_CAST(op);

if (_PyEvent_IsSet(&self->handle->thread_is_exiting)) {

Py_RETURN_TRUE;

}

else {

Py_RETURN_FALSE;

}

}

static PyObject *

PyThreadHandleObject_set_done(PyObject *op, PyObject *Py_UNUSED(dummy))

{

PyThreadHandleObject *self = PyThreadHandleObject_CAST(op);

if (ThreadHandle_set_done(self->handle) < 0) {

return NULL;

}

Py_RETURN_NONE;

}

static PyGetSetDef ThreadHandle_getsetlist[] = {

{"ident", PyThreadHandleObject_get_ident, NULL, NULL},

{0},

};

static PyMethodDef ThreadHandle_methods[] = {

{"join", PyThreadHandleObject_join, METH_VARARGS, NULL},

{"_set_done", PyThreadHandleObject_set_done, METH_NOARGS, NULL},

{"is_done", PyThreadHandleObject_is_done, METH_NOARGS, NULL},

{0, 0}

};

static PyType_Slot ThreadHandle_Type_slots[] = {

{Py_tp_dealloc, PyThreadHandleObject_dealloc},

{Py_tp_repr, PyThreadHandleObject_repr},

{Py_tp_getset, ThreadHandle_getsetlist},

{Py_tp_traverse, PyThreadHandleObject_traverse},

{Py_tp_methods, ThreadHandle_methods},

{Py_tp_new, PyThreadHandleObject_tp_new},

{0, 0}

};

static PyType_Spec ThreadHandle_Type_spec = {

"_thread._ThreadHandle",

sizeof(PyThreadHandleObject),

0,

Py_TPFLAGS_DEFAULT | Py_TPFLAGS_IMMUTABLETYPE | Py_TPFLAGS_HAVE_GC,

ThreadHandle_Type_slots,

};

/* Lock objects */

typedef struct {

PyObject_HEAD

PyMutex lock;

} lockobject;

#define lockobject_CAST(op) ((lockobject *)(op))

static int

lock_traverse(PyObject *self, visitproc visit, void *arg)

{

Py_VISIT(Py_TYPE(self));

return 0;

}

static void

lock_dealloc(PyObject *self)

{

PyObject_GC_UnTrack(self);

PyObject_ClearWeakRefs(self);

PyTypeObject *tp = Py_TYPE(self);

tp->tp_free(self);

Py_DECREF(tp);

}

static int

lock_acquire_parse_args(PyObject *args, PyObject *kwds,

PyTime_t *timeout)

{

char *kwlist[] = {"blocking", "timeout", NULL};

int blocking = 1;

PyObject *timeout_obj = NULL;

if (!PyArg_ParseTupleAndKeywords(args, kwds, "|pO:acquire", kwlist,

&blocking, &timeout_obj))

return -1;

// XXX Use PyThread_ParseTimeoutArg().

const PyTime_t unset_timeout = _PyTime_FromSeconds(-1);

*timeout = unset_timeout;

if (timeout_obj

&& _PyTime_FromSecondsObject(timeout,

timeout_obj, _PyTime_ROUND_TIMEOUT) < 0)

return -1;

if (!blocking && *timeout != unset_timeout ) {

PyErr_SetString(PyExc_ValueError,

"can't specify a timeout for a non-blocking call");

return -1;

}

if (*timeout < 0 && *timeout != unset_timeout) {

PyErr_SetString(PyExc_ValueError,

"timeout value must be a non-negative number");

return -1;

}

if (!blocking)

*timeout = 0;

else if (*timeout != unset_timeout) {

PyTime_t microseconds;

microseconds = _PyTime_AsMicroseconds(*timeout, _PyTime_ROUND_TIMEOUT);

if (microseconds > PY_TIMEOUT_MAX) {

PyErr_SetString(PyExc_OverflowError,

"timeout value is too large");

return -1;

}

}

return 0;

}

static PyObject *

lock_PyThread_acquire_lock(PyObject *op, PyObject *args, PyObject *kwds)

{

lockobject *self = lockobject_CAST(op);

PyTime_t timeout;

if (lock_acquire_parse_args(args, kwds, &timeout) < 0) {

return NULL;

}

PyLockStatus r = _PyMutex_LockTimed(&self->lock, timeout,

_PY_LOCK_HANDLE_SIGNALS | _PY_LOCK_DETACH);

if (r == PY_LOCK_INTR) {

return NULL;

}

return PyBool_FromLong(r == PY_LOCK_ACQUIRED);

}

PyDoc_STRVAR(acquire_doc,

"acquire($self, /, blocking=True, timeout=-1)\n\

--\n\

\n\

Lock the lock. Without argument, this blocks if the lock is already\n\

locked (even by the same thread), waiting for another thread to release\n\

the lock, and return True once the lock is acquired.\n\

With an argument, this will only block if the argument is true,\n\

and the return value reflects whether the lock is acquired.\n\

The blocking operation is interruptible.");

PyDoc_STRVAR(acquire_lock_doc,

"acquire_lock($self, /, blocking=True, timeout=-1)\n\

--\n\

\n\

An obsolete synonym of acquire().");

PyDoc_STRVAR(enter_doc,

"__enter__($self, /)\n\

--\n\

\n\

Lock the lock.");

static PyObject *

lock_PyThread_release_lock(PyObject *op, PyObject *Py_UNUSED(dummy))

{

lockobject *self = lockobject_CAST(op);

/* Sanity check: the lock must be locked */

if (_PyMutex_TryUnlock(&self->lock) < 0) {

PyErr_SetString(ThreadError, "release unlocked lock");

return NULL;

}

Py_RETURN_NONE;

}

PyDoc_STRVAR(release_doc,

"release($self, /)\n\

--\n\

\n\

Release the lock, allowing another thread that is blocked waiting for\n\

the lock to acquire the lock. The lock must be in the locked state,\n\

but it needn't be locked by the same thread that unlocks it.");

PyDoc_STRVAR(release_lock_doc,

"release_lock($self, /)\n\

--\n\

\n\

An obsolete synonym of release().");

PyDoc_STRVAR(lock_exit_doc,

"__exit__($self, /, *exc_info)\n\

--\n\

\n\

Release the lock.");

static PyObject *

lock_locked_lock(PyObject *op, PyObject *Py_UNUSED(dummy))

{

lockobject *self = lockobject_CAST(op);

return PyBool_FromLong(PyMutex_IsLocked(&self->lock));

}

PyDoc_STRVAR(locked_doc,

"locked($self, /)\n\

--\n\

\n\

Return whether the lock is in the locked state.");

PyDoc_STRVAR(locked_lock_doc,

"locked_lock($self, /)\n\

--\n\

\n\

An obsolete synonym of locked().");

static PyObject *

lock_repr(PyObject *op)

{

lockobject *self = lockobject_CAST(op);

return PyUnicode_FromFormat("<%s %s object at %p>",

PyMutex_IsLocked(&self->lock) ? "locked" : "unlocked", Py_TYPE(self)->tp_name, self);

}

#ifdef HAVE_FORK

static PyObject *

lock__at_fork_reinit(PyObject *op, PyObject *Py_UNUSED(dummy))

{

lockobject *self = lockobject_CAST(op);

_PyMutex_at_fork_reinit(&self->lock);

Py_RETURN_NONE;

}

#endif /* HAVE_FORK */

/*[clinic input]

@classmethod

_thread.lock.__new__ as lock_new

[clinic start generated code]*/

static PyObject *

lock_new_impl(PyTypeObject *type)

/*[clinic end generated code: output=eab660d5a4c05c8a input=260208a4e277d250]*/

{

lockobject *self = (lockobject *)type->tp_alloc(type, 0);

if (self == NULL) {

return NULL;

}

self->lock = (PyMutex){0};

return (PyObject *)self;

}

static PyMethodDef lock_methods[] = {

{"acquire_lock", _PyCFunction_CAST(lock_PyThread_acquire_lock),

METH_VARARGS | METH_KEYWORDS, acquire_lock_doc},

{"acquire", _PyCFunction_CAST(lock_PyThread_acquire_lock),

METH_VARARGS | METH_KEYWORDS, acquire_doc},

{"release_lock", lock_PyThread_release_lock,

METH_NOARGS, release_lock_doc},

{"release", lock_PyThread_release_lock,

METH_NOARGS, release_doc},

{"locked_lock", lock_locked_lock,

METH_NOARGS, locked_lock_doc},

{"locked", lock_locked_lock,

METH_NOARGS, locked_doc},

{"__enter__", _PyCFunction_CAST(lock_PyThread_acquire_lock),

METH_VARARGS | METH_KEYWORDS, enter_doc},

{"__exit__", lock_PyThread_release_lock,

METH_VARARGS, lock_exit_doc},

#ifdef HAVE_FORK

{"_at_fork_reinit", lock__at_fork_reinit,

METH_NOARGS, NULL},

#endif

{NULL, NULL} /* sentinel */

};

PyDoc_STRVAR(lock_doc,

"lock()\n\

--\n\

\n\

A lock object is a synchronization primitive. To create a lock,\n\

call threading.Lock(). Methods are:\n\

\n\

acquire() -- lock the lock, possibly blocking until it can be obtained\n\

release() -- unlock of the lock\n\

locked() -- test whether the lock is currently locked\n\

\n\

A lock is not owned by the thread that locked it; another thread may\n\

unlock it. A thread attempting to lock a lock that it has already locked\n\

will block until another thread unlocks it. Deadlocks may ensue.");

static PyType_Slot lock_type_slots[] = {

{Py_tp_dealloc, lock_dealloc},

{Py_tp_repr, lock_repr},

{Py_tp_doc, (void *)lock_doc},

{Py_tp_methods, lock_methods},

{Py_tp_traverse, lock_traverse},

{Py_tp_new, lock_new},

{0, 0}

};