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29cbcbd73b
cpython/Python/thread_pthread.h
Jeremy Maitin-Shepard 8cc5aa47ee
gh-87135: Hang non-main threads that attempt to acquire the GIL during finalization (GH-105805) 
Instead of surprise crashes and memory corruption, we now hang threads that attempt to re-enter the Python interpreter after Python runtime finalization has started. These are typically daemon threads (our long standing mis-feature) but could also be threads spawned by extension modules that then try to call into Python. This marks the `PyThread_exit_thread` public C API as deprecated as there is no plausible safe way to accomplish that on any supported platform in the face of things like C++ code with finalizers anywhere on a thread's stack. Doing this was the least bad option.

Co-authored-by: Gregory P. Smith <greg@krypto.org>
2024-10-02 09:17:49 -07:00

991 lines
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#include "pycore_interp.h" // _PyInterpreterState.threads.stacksize
#include "pycore_pythread.h" // _POSIX_SEMAPHORES
#include "pycore_time.h" // _PyTime_FromMicrosecondsClamup()
/* Posix threads interface */
#include <stdlib.h>
#include <string.h>
#if defined(__APPLE__) || defined(HAVE_PTHREAD_DESTRUCTOR)
#define destructor xxdestructor
#endif
#ifndef HAVE_PTHREAD_STUBS
# include <pthread.h>
#endif
#if defined(__APPLE__) || defined(HAVE_PTHREAD_DESTRUCTOR)
#undef destructor
#endif
#include <signal.h>
#include <unistd.h> /* pause(), also getthrid() on OpenBSD */
#if defined(__linux__)
# include <sys/syscall.h> /* syscall(SYS_gettid) */
#elif defined(__FreeBSD__)
# include <pthread_np.h> /* pthread_getthreadid_np() */
#elif defined(__FreeBSD_kernel__)
# include <sys/syscall.h> /* syscall(SYS_thr_self) */
#elif defined(_AIX)
# include <sys/thread.h> /* thread_self() */
#elif defined(__NetBSD__)
# include <lwp.h> /* _lwp_self() */
#elif defined(__DragonFly__)
# include <sys/lwp.h> /* lwp_gettid() */
#endif
/* The POSIX spec requires that use of pthread_attr_setstacksize
be conditional on _POSIX_THREAD_ATTR_STACKSIZE being defined. */
#ifdef _POSIX_THREAD_ATTR_STACKSIZE
#ifndef THREAD_STACK_SIZE
#define THREAD_STACK_SIZE 0 /* use default stack size */
#endif
/* The default stack size for new threads on BSD is small enough that
* we'll get hard crashes instead of 'maximum recursion depth exceeded'
* exceptions.
*
* The default stack size below is the empirically determined minimal stack
* sizes where a simple recursive function doesn't cause a hard crash.
*
* For macOS the value of THREAD_STACK_SIZE is determined in configure.ac
* as it also depends on the other configure options like chosen sanitizer
* runtimes.
*/
#if defined(__FreeBSD__) && defined(THREAD_STACK_SIZE) && THREAD_STACK_SIZE == 0
#undef THREAD_STACK_SIZE
#define THREAD_STACK_SIZE 0x400000
#endif
#if defined(_AIX) && defined(THREAD_STACK_SIZE) && THREAD_STACK_SIZE == 0
#undef THREAD_STACK_SIZE
#define THREAD_STACK_SIZE 0x200000
#endif
/* bpo-38852: test_threading.test_recursion_limit() checks that 1000 recursive
Python calls (default recursion limit) doesn't crash, but raise a regular
RecursionError exception. In debug mode, Python function calls allocates
more memory on the stack, so use a stack of 8 MiB. */
#if defined(__ANDROID__) && defined(THREAD_STACK_SIZE) && THREAD_STACK_SIZE == 0
# ifdef Py_DEBUG
# undef THREAD_STACK_SIZE
# define THREAD_STACK_SIZE 0x800000
# endif
#endif
#if defined(__VXWORKS__) && defined(THREAD_STACK_SIZE) && THREAD_STACK_SIZE == 0
#undef THREAD_STACK_SIZE
#define THREAD_STACK_SIZE 0x100000
#endif
/* for safety, ensure a viable minimum stacksize */
#define THREAD_STACK_MIN 0x8000 /* 32 KiB */
#else /* !_POSIX_THREAD_ATTR_STACKSIZE */
#ifdef THREAD_STACK_SIZE
#error "THREAD_STACK_SIZE defined but _POSIX_THREAD_ATTR_STACKSIZE undefined"
#endif
#endif
/* The POSIX spec says that implementations supporting the sem_*
family of functions must indicate this by defining
_POSIX_SEMAPHORES. */
#ifdef _POSIX_SEMAPHORES
/* On FreeBSD 4.x, _POSIX_SEMAPHORES is defined empty, so
we need to add 0 to make it work there as well. */
#if (_POSIX_SEMAPHORES+0) == -1
# define HAVE_BROKEN_POSIX_SEMAPHORES
#else
# include <semaphore.h>
# include <errno.h>
#endif
#endif
/* Thread sanitizer doesn't currently support sem_clockwait */
#ifdef _Py_THREAD_SANITIZER
#undef HAVE_SEM_CLOCKWAIT
#endif
/* Whether or not to use semaphores directly rather than emulating them with
* mutexes and condition variables:
*/
#if (defined(_POSIX_SEMAPHORES) && !defined(HAVE_BROKEN_POSIX_SEMAPHORES) && \
(defined(HAVE_SEM_TIMEDWAIT) || defined(HAVE_SEM_CLOCKWAIT)))
# define USE_SEMAPHORES
#else
# undef USE_SEMAPHORES
#endif
/* On platforms that don't use standard POSIX threads pthread_sigmask()
* isn't present. DEC threads uses sigprocmask() instead as do most
* other UNIX International compliant systems that don't have the full
* pthread implementation.
*/
#if defined(HAVE_PTHREAD_SIGMASK) && !defined(HAVE_BROKEN_PTHREAD_SIGMASK)
# define SET_THREAD_SIGMASK pthread_sigmask
#else
# define SET_THREAD_SIGMASK sigprocmask
#endif
/*
* pthread_cond support
*/
#define condattr_monotonic _PyRuntime.threads._condattr_monotonic.ptr
static void
init_condattr(void)
{
#ifdef CONDATTR_MONOTONIC
# define ca _PyRuntime.threads._condattr_monotonic.val
// XXX We need to check the return code?
pthread_condattr_init(&ca);
// XXX We need to run pthread_condattr_destroy() during runtime fini.
if (pthread_condattr_setclock(&ca, CLOCK_MONOTONIC) == 0) {
condattr_monotonic = &ca; // Use monotonic clock
}
# undef ca
#endif // CONDATTR_MONOTONIC
}
int
_PyThread_cond_init(PyCOND_T *cond)
{
return pthread_cond_init(cond, condattr_monotonic);
}
void
_PyThread_cond_after(long long us, struct timespec *abs)
{
PyTime_t timeout = _PyTime_FromMicrosecondsClamp(us);
PyTime_t t;
#ifdef CONDATTR_MONOTONIC
if (condattr_monotonic) {
// silently ignore error: cannot report error to the caller
(void)PyTime_MonotonicRaw(&t);
}
else
#endif
{
// silently ignore error: cannot report error to the caller
(void)PyTime_TimeRaw(&t);
}
t = _PyTime_Add(t, timeout);
_PyTime_AsTimespec_clamp(t, abs);
}
/* A pthread mutex isn't sufficient to model the Python lock type
* because, according to Draft 5 of the docs (P1003.4a/D5), both of the
* following are undefined:
* -> a thread tries to lock a mutex it already has locked
* -> a thread tries to unlock a mutex locked by a different thread
* pthread mutexes are designed for serializing threads over short pieces
* of code anyway, so wouldn't be an appropriate implementation of
* Python's locks regardless.
*
* The pthread_lock struct implements a Python lock as a "locked?" bit
* and a <condition, mutex> pair. In general, if the bit can be acquired
* instantly, it is, else the pair is used to block the thread until the
* bit is cleared. 9 May 1994 tim@ksr.com
*/
typedef struct {
char locked; /* 0=unlocked, 1=locked */
/* a <cond, mutex> pair to handle an acquire of a locked lock */
pthread_cond_t lock_released;
pthread_mutex_t mut;
} pthread_lock;
#define CHECK_STATUS(name) if (status != 0) { perror(name); error = 1; }
#define CHECK_STATUS_PTHREAD(name) if (status != 0) { fprintf(stderr, \
"%s: %s\n", name, strerror(status)); error = 1; }
/*
* Initialization for the current runtime.
*/
static void
PyThread__init_thread(void)
{
// The library is only initialized once in the process,
// regardless of how many times the Python runtime is initialized.
static int lib_initialized = 0;
if (!lib_initialized) {
lib_initialized = 1;
#if defined(_AIX) && defined(__GNUC__)
extern void pthread_init(void);
pthread_init();
#endif
}
init_condattr();
}
/*
* Thread support.
*/
/* bpo-33015: pythread_callback struct and pythread_wrapper() cast
"void func(void *)" to "void* func(void *)": always return NULL.
PyThread_start_new_thread() uses "void func(void *)" type, whereas
pthread_create() requires a void* return value. */
typedef struct {
void (*func) (void *);
void *arg;
} pythread_callback;
static void *
pythread_wrapper(void *arg)
{
/* copy func and func_arg and free the temporary structure */
pythread_callback *callback = arg;
void (*func)(void *) = callback->func;
void *func_arg = callback->arg;
PyMem_RawFree(arg);
func(func_arg);
return NULL;
}
static int
do_start_joinable_thread(void (*func)(void *), void *arg, pthread_t* out_id)
{
pthread_t th;
int status;
#if defined(THREAD_STACK_SIZE) || defined(PTHREAD_SYSTEM_SCHED_SUPPORTED)
pthread_attr_t attrs;
#endif
#if defined(THREAD_STACK_SIZE)
size_t tss;
#endif
if (!initialized)
PyThread_init_thread();
#if defined(THREAD_STACK_SIZE) || defined(PTHREAD_SYSTEM_SCHED_SUPPORTED)
if (pthread_attr_init(&attrs) != 0)
return -1;
#endif
#if defined(THREAD_STACK_SIZE)
PyThreadState *tstate = _PyThreadState_GET();
size_t stacksize = tstate ? tstate->interp->threads.stacksize : 0;
tss = (stacksize != 0) ? stacksize : THREAD_STACK_SIZE;
if (tss != 0) {
if (pthread_attr_setstacksize(&attrs, tss) != 0) {
pthread_attr_destroy(&attrs);
return -1;
}
}
#endif
#if defined(PTHREAD_SYSTEM_SCHED_SUPPORTED)
pthread_attr_setscope(&attrs, PTHREAD_SCOPE_SYSTEM);
#endif
pythread_callback *callback = PyMem_RawMalloc(sizeof(pythread_callback));
if (callback == NULL) {
return -1;
}
callback->func = func;
callback->arg = arg;
status = pthread_create(&th,
#if defined(THREAD_STACK_SIZE) || defined(PTHREAD_SYSTEM_SCHED_SUPPORTED)
&attrs,
#else
(pthread_attr_t*)NULL,
#endif
pythread_wrapper, callback);
#if defined(THREAD_STACK_SIZE) || defined(PTHREAD_SYSTEM_SCHED_SUPPORTED)
pthread_attr_destroy(&attrs);
#endif
if (status != 0) {
PyMem_RawFree(callback);
return -1;
}
*out_id = th;
return 0;
}
int
PyThread_start_joinable_thread(void (*func)(void *), void *arg,
PyThread_ident_t* ident, PyThread_handle_t* handle) {
pthread_t th = (pthread_t) 0;
if (do_start_joinable_thread(func, arg, &th)) {
return -1;
}
*ident = (PyThread_ident_t) th;
*handle = (PyThread_handle_t) th;
assert(th == (pthread_t) *ident);
assert(th == (pthread_t) *handle);
return 0;
}
unsigned long
PyThread_start_new_thread(void (*func)(void *), void *arg)
{
pthread_t th = (pthread_t) 0;
if (do_start_joinable_thread(func, arg, &th)) {
return PYTHREAD_INVALID_THREAD_ID;
}
pthread_detach(th);
#if SIZEOF_PTHREAD_T <= SIZEOF_LONG
return (unsigned long) th;
#else
return (unsigned long) *(unsigned long *) &th;
#endif
}
int
PyThread_join_thread(PyThread_handle_t th) {
return pthread_join((pthread_t) th, NULL);
}
int
PyThread_detach_thread(PyThread_handle_t th) {
return pthread_detach((pthread_t) th);
}
/* XXX This implementation is considered (to quote Tim Peters) "inherently
hosed" because:
- It does not guarantee the promise that a non-zero integer is returned.
- The cast to unsigned long is inherently unsafe.
- It is not clear that the 'volatile' (for AIX?) are any longer necessary.
*/
PyThread_ident_t
PyThread_get_thread_ident_ex(void) {
volatile pthread_t threadid;
if (!initialized)
PyThread_init_thread();
threadid = pthread_self();
assert(threadid == (pthread_t) (PyThread_ident_t) threadid);
return (PyThread_ident_t) threadid;
}
unsigned long
PyThread_get_thread_ident(void)
{
return (unsigned long) PyThread_get_thread_ident_ex();
}
#ifdef PY_HAVE_THREAD_NATIVE_ID
unsigned long
PyThread_get_thread_native_id(void)
{
if (!initialized)
PyThread_init_thread();
#ifdef __APPLE__
uint64_t native_id;
(void) pthread_threadid_np(NULL, &native_id);
#elif defined(__linux__)
pid_t native_id;
native_id = syscall(SYS_gettid);
#elif defined(__FreeBSD__)
int native_id;
native_id = pthread_getthreadid_np();
#elif defined(__FreeBSD_kernel__)
long native_id;
syscall(SYS_thr_self, &native_id);
#elif defined(__OpenBSD__)
pid_t native_id;
native_id = getthrid();
#elif defined(_AIX)
tid_t native_id;
native_id = thread_self();
#elif defined(__NetBSD__)
lwpid_t native_id;
native_id = _lwp_self();
#elif defined(__DragonFly__)
lwpid_t native_id;
native_id = lwp_gettid();
#endif
return (unsigned long) native_id;
}
#endif
void _Py_NO_RETURN
PyThread_exit_thread(void)
{
if (!initialized)
exit(0);
#if defined(__wasi__)
/*
* wasi-threads doesn't have pthread_exit right now
* cf. https://github.com/WebAssembly/wasi-threads/issues/7
*/
abort();
#else
pthread_exit(0);
#endif
}
void _Py_NO_RETURN
PyThread_hang_thread(void)
{
while (1) {
#if defined(__wasi__)
sleep(9999999); // WASI doesn't have pause() ?!
#else
pause();
#endif
}
}
#ifdef USE_SEMAPHORES
/*
* Lock support.
*/
PyThread_type_lock
PyThread_allocate_lock(void)
{
sem_t *lock;
int status, error = 0;
if (!initialized)
PyThread_init_thread();
lock = (sem_t *)PyMem_RawMalloc(sizeof(sem_t));
if (lock) {
status = sem_init(lock,0,1);
CHECK_STATUS("sem_init");
if (error) {
PyMem_RawFree((void *)lock);
lock = NULL;
}
}
return (PyThread_type_lock)lock;
}
void
PyThread_free_lock(PyThread_type_lock lock)
{
sem_t *thelock = (sem_t *)lock;
int status, error = 0;
(void) error; /* silence unused-but-set-variable warning */
if (!thelock)
return;
status = sem_destroy(thelock);
CHECK_STATUS("sem_destroy");
PyMem_RawFree((void *)thelock);
}
/*
* As of February 2002, Cygwin thread implementations mistakenly report error
* codes in the return value of the sem_ calls (like the pthread_ functions).
* Correct implementations return -1 and put the code in errno. This supports
* either.
*/
static int
fix_status(int status)
{
return (status == -1) ? errno : status;
}
PyLockStatus
PyThread_acquire_lock_timed(PyThread_type_lock lock, PY_TIMEOUT_T microseconds,
int intr_flag)
{
PyLockStatus success;
sem_t *thelock = (sem_t *)lock;
int status, error = 0;
(void) error; /* silence unused-but-set-variable warning */
PyTime_t timeout; // relative timeout
if (microseconds >= 0) {
// bpo-41710: PyThread_acquire_lock_timed() cannot report timeout
// overflow to the caller, so clamp the timeout to
// [PyTime_MIN, PyTime_MAX].
//
// PyTime_MAX nanoseconds is around 292.3 years.
//
// _thread.Lock.acquire() and _thread.RLock.acquire() raise an
// OverflowError if microseconds is greater than PY_TIMEOUT_MAX.
timeout = _PyTime_FromMicrosecondsClamp(microseconds);
}
else {
timeout = -1;
}
#ifdef HAVE_SEM_CLOCKWAIT
struct timespec abs_timeout;
// Local scope for deadline
{
PyTime_t now;
// silently ignore error: cannot report error to the caller
(void)PyTime_MonotonicRaw(&now);
PyTime_t deadline = _PyTime_Add(now, timeout);
_PyTime_AsTimespec_clamp(deadline, &abs_timeout);
}
#else
PyTime_t deadline = 0;
if (timeout > 0 && !intr_flag) {
deadline = _PyDeadline_Init(timeout);
}
#endif
while (1) {
if (timeout > 0) {
#ifdef HAVE_SEM_CLOCKWAIT
status = fix_status(sem_clockwait(thelock, CLOCK_MONOTONIC,
&abs_timeout));
#else
PyTime_t now;
// silently ignore error: cannot report error to the caller
(void)PyTime_TimeRaw(&now);
PyTime_t abs_time = _PyTime_Add(now, timeout);
struct timespec ts;
_PyTime_AsTimespec_clamp(abs_time, &ts);
status = fix_status(sem_timedwait(thelock, &ts));
#endif
}
else if (timeout == 0) {
status = fix_status(sem_trywait(thelock));
}
else {
status = fix_status(sem_wait(thelock));
}
/* Retry if interrupted by a signal, unless the caller wants to be
notified. */
if (intr_flag || status != EINTR) {
break;
}
// sem_clockwait() uses an absolute timeout, there is no need
// to recompute the relative timeout.
#ifndef HAVE_SEM_CLOCKWAIT
if (timeout > 0) {
/* wait interrupted by a signal (EINTR): recompute the timeout */
timeout = _PyDeadline_Get(deadline);
if (timeout < 0) {
status = ETIMEDOUT;
break;
}
}
#endif
}
/* Don't check the status if we're stopping because of an interrupt. */
if (!(intr_flag && status == EINTR)) {
if (timeout > 0) {
if (status != ETIMEDOUT) {
#ifdef HAVE_SEM_CLOCKWAIT
CHECK_STATUS("sem_clockwait");
#else
CHECK_STATUS("sem_timedwait");
#endif
}
}
else if (timeout == 0) {
if (status != EAGAIN) {
CHECK_STATUS("sem_trywait");
}
}
else {
CHECK_STATUS("sem_wait");
}
}
if (status == 0) {
success = PY_LOCK_ACQUIRED;
} else if (intr_flag && status == EINTR) {
success = PY_LOCK_INTR;
} else {
success = PY_LOCK_FAILURE;
}
return success;
}
void
PyThread_release_lock(PyThread_type_lock lock)
{
sem_t *thelock = (sem_t *)lock;
int status, error = 0;
(void) error; /* silence unused-but-set-variable warning */
status = sem_post(thelock);
CHECK_STATUS("sem_post");
}
#else /* USE_SEMAPHORES */
/*
* Lock support.
*/
PyThread_type_lock
PyThread_allocate_lock(void)
{
pthread_lock *lock;
int status, error = 0;
if (!initialized)
PyThread_init_thread();
lock = (pthread_lock *) PyMem_RawCalloc(1, sizeof(pthread_lock));
if (lock) {
lock->locked = 0;
status = pthread_mutex_init(&lock->mut, NULL);
CHECK_STATUS_PTHREAD("pthread_mutex_init");
/* Mark the pthread mutex underlying a Python mutex as
pure happens-before. We can't simply mark the
Python-level mutex as a mutex because it can be
acquired and released in different threads, which
will cause errors. */
_Py_ANNOTATE_PURE_HAPPENS_BEFORE_MUTEX(&lock->mut);
status = _PyThread_cond_init(&lock->lock_released);
CHECK_STATUS_PTHREAD("pthread_cond_init");
if (error) {
PyMem_RawFree((void *)lock);
lock = 0;
}
}
return (PyThread_type_lock) lock;
}
void
PyThread_free_lock(PyThread_type_lock lock)
{
pthread_lock *thelock = (pthread_lock *)lock;
int status, error = 0;
(void) error; /* silence unused-but-set-variable warning */
/* some pthread-like implementations tie the mutex to the cond
* and must have the cond destroyed first.
*/
status = pthread_cond_destroy( &thelock->lock_released );
CHECK_STATUS_PTHREAD("pthread_cond_destroy");
status = pthread_mutex_destroy( &thelock->mut );
CHECK_STATUS_PTHREAD("pthread_mutex_destroy");
PyMem_RawFree((void *)thelock);
}
PyLockStatus
PyThread_acquire_lock_timed(PyThread_type_lock lock, PY_TIMEOUT_T microseconds,
int intr_flag)
{
PyLockStatus success = PY_LOCK_FAILURE;
pthread_lock *thelock = (pthread_lock *)lock;
int status, error = 0;
if (microseconds == 0) {
status = pthread_mutex_trylock( &thelock->mut );
if (status != EBUSY) {
CHECK_STATUS_PTHREAD("pthread_mutex_trylock[1]");
}
}
else {
status = pthread_mutex_lock( &thelock->mut );
CHECK_STATUS_PTHREAD("pthread_mutex_lock[1]");
}
if (status != 0) {
goto done;
}
if (thelock->locked == 0) {
success = PY_LOCK_ACQUIRED;
goto unlock;
}
if (microseconds == 0) {
goto unlock;
}
struct timespec abs_timeout;
if (microseconds > 0) {
_PyThread_cond_after(microseconds, &abs_timeout);
}
// Continue trying until we get the lock
// mut must be locked by me -- part of the condition protocol
while (1) {
if (microseconds > 0) {
status = pthread_cond_timedwait(&thelock->lock_released,
&thelock->mut, &abs_timeout);
if (status == 1) {
break;
}
if (status == ETIMEDOUT) {
break;
}
CHECK_STATUS_PTHREAD("pthread_cond_timedwait");
}
else {
status = pthread_cond_wait(
&thelock->lock_released,
&thelock->mut);
CHECK_STATUS_PTHREAD("pthread_cond_wait");
}
if (intr_flag && status == 0 && thelock->locked) {
// We were woken up, but didn't get the lock. We probably received
// a signal. Return PY_LOCK_INTR to allow the caller to handle
// it and retry.
success = PY_LOCK_INTR;
break;
}
if (status == 0 && !thelock->locked) {
success = PY_LOCK_ACQUIRED;
break;
}
// Wait got interrupted by a signal: retry
}
unlock:
if (success == PY_LOCK_ACQUIRED) {
thelock->locked = 1;
}
status = pthread_mutex_unlock( &thelock->mut );
CHECK_STATUS_PTHREAD("pthread_mutex_unlock[1]");
done:
if (error) {
success = PY_LOCK_FAILURE;
}
return success;
}
void
PyThread_release_lock(PyThread_type_lock lock)
{
pthread_lock *thelock = (pthread_lock *)lock;
int status, error = 0;
(void) error; /* silence unused-but-set-variable warning */
status = pthread_mutex_lock( &thelock->mut );
CHECK_STATUS_PTHREAD("pthread_mutex_lock[3]");
thelock->locked = 0;
/* wake up someone (anyone, if any) waiting on the lock */
status = pthread_cond_signal( &thelock->lock_released );
CHECK_STATUS_PTHREAD("pthread_cond_signal");
status = pthread_mutex_unlock( &thelock->mut );
CHECK_STATUS_PTHREAD("pthread_mutex_unlock[3]");
}
#endif /* USE_SEMAPHORES */
int
_PyThread_at_fork_reinit(PyThread_type_lock *lock)
{
PyThread_type_lock new_lock = PyThread_allocate_lock();
if (new_lock == NULL) {
return -1;
}
/* bpo-6721, bpo-40089: The old lock can be in an inconsistent state.
fork() can be called in the middle of an operation on the lock done by
another thread. So don't call PyThread_free_lock(*lock).
Leak memory on purpose. Don't release the memory either since the
address of a mutex is relevant. Putting two mutexes at the same address
can lead to problems. */
*lock = new_lock;
return 0;
}
int
PyThread_acquire_lock(PyThread_type_lock lock, int waitflag)
{
return PyThread_acquire_lock_timed(lock, waitflag ? -1 : 0, /*intr_flag=*/0);
}
/* set the thread stack size.
* Return 0 if size is valid, -1 if size is invalid,
* -2 if setting stack size is not supported.
*/
static int
_pythread_pthread_set_stacksize(size_t size)
{
#if defined(THREAD_STACK_SIZE)
pthread_attr_t attrs;
size_t tss_min;
int rc = 0;
#endif
/* set to default */
if (size == 0) {
_PyInterpreterState_GET()->threads.stacksize = 0;
return 0;
}
#if defined(THREAD_STACK_SIZE)
#if defined(PTHREAD_STACK_MIN)
tss_min = PTHREAD_STACK_MIN > THREAD_STACK_MIN ? PTHREAD_STACK_MIN
: THREAD_STACK_MIN;
#else
tss_min = THREAD_STACK_MIN;
#endif
if (size >= tss_min) {
/* validate stack size by setting thread attribute */
if (pthread_attr_init(&attrs) == 0) {
rc = pthread_attr_setstacksize(&attrs, size);
pthread_attr_destroy(&attrs);
if (rc == 0) {
_PyInterpreterState_GET()->threads.stacksize = size;
return 0;
}
}
}
return -1;
#else
return -2;
#endif
}
#define THREAD_SET_STACKSIZE(x) _pythread_pthread_set_stacksize(x)
/* Thread Local Storage (TLS) API
This API is DEPRECATED since Python 3.7. See PEP 539 for details.
*/
/* Issue #25658: On platforms where native TLS key is defined in a way that
cannot be safely cast to int, PyThread_create_key returns immediately a
failure status and other TLS functions all are no-ops. This indicates
clearly that the old API is not supported on platforms where it cannot be
used reliably, and that no effort will be made to add such support.
Note: PTHREAD_KEY_T_IS_COMPATIBLE_WITH_INT will be unnecessary after
removing this API.
*/
int
PyThread_create_key(void)
{
#ifdef PTHREAD_KEY_T_IS_COMPATIBLE_WITH_INT
pthread_key_t key;
int fail = pthread_key_create(&key, NULL);
if (fail)
return -1;
if (key > INT_MAX) {
/* Issue #22206: handle integer overflow */
pthread_key_delete(key);
errno = ENOMEM;
return -1;
}
return (int)key;
#else
return -1; /* never return valid key value. */
#endif
}
void
PyThread_delete_key(int key)
{
#ifdef PTHREAD_KEY_T_IS_COMPATIBLE_WITH_INT
pthread_key_delete(key);
#endif
}
void
PyThread_delete_key_value(int key)
{
#ifdef PTHREAD_KEY_T_IS_COMPATIBLE_WITH_INT
pthread_setspecific(key, NULL);
#endif
}
int
PyThread_set_key_value(int key, void *value)
{
#ifdef PTHREAD_KEY_T_IS_COMPATIBLE_WITH_INT
int fail = pthread_setspecific(key, value);
return fail ? -1 : 0;
#else
return -1;
#endif
}
void *
PyThread_get_key_value(int key)
{
#ifdef PTHREAD_KEY_T_IS_COMPATIBLE_WITH_INT
return pthread_getspecific(key);
#else
return NULL;
#endif
}
void
PyThread_ReInitTLS(void)
{
}
/* Thread Specific Storage (TSS) API
Platform-specific components of TSS API implementation.
*/
int
PyThread_tss_create(Py_tss_t *key)
{
assert(key != NULL);
/* If the key has been created, function is silently skipped. */
if (key->_is_initialized) {
return 0;
}
int fail = pthread_key_create(&(key->_key), NULL);
if (fail) {
return -1;
}
key->_is_initialized = 1;
return 0;
}
void
PyThread_tss_delete(Py_tss_t *key)
{
assert(key != NULL);
/* If the key has not been created, function is silently skipped. */
if (!key->_is_initialized) {
return;
}
pthread_key_delete(key->_key);
/* pthread has not provided the defined invalid value for the key. */
key->_is_initialized = 0;
}
int
PyThread_tss_set(Py_tss_t *key, void *value)
{
assert(key != NULL);
int fail = pthread_setspecific(key->_key, value);
return fail ? -1 : 0;
}
void *
PyThread_tss_get(Py_tss_t *key)
{
assert(key != NULL);
return pthread_getspecific(key->_key);
}
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