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cpython/Python/thread_pthread.h
Vincent Fazio 72123063dd
gh-130115: fix thread identifiers for 32-bit musl (#130391) 
CPython's pthread-based thread identifier relies on pthread_t being able
to be represented as an unsigned integer type.

This is true in most Linux libc implementations where it's defined as an
unsigned long, however musl typedefs it as a struct *.

If the pointer has the high bit set and is cast to PyThread_ident_t, the
resultant value can be sign-extended [0]. This can cause issues when
comparing against threading._MainThread's identifier. The main thread's
identifier value is retrieved via _get_main_thread_ident which is backed
by an unsigned long which truncates sign extended bits.

  >>> hex(threading.main_thread().ident)
  '0xb6f33f3c'
  >>> hex(threading.current_thread().ident)
  '0xffffffffb6f33f3c'

Work around this by conditionally compiling in some code for non-glibc
based Linux platforms that are at risk of sign-extension to return a
PyLong based on the main thread's unsigned long thread identifier if the
current thread is the main thread.

[0]: https://gcc.gnu.org/onlinedocs/gcc-14.2.0/gcc/Arrays-and-pointers-implementation.html

---------

Signed-off-by: Vincent Fazio <vfazio@gmail.com>
2025-04-04 16:31:37 +02:00

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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;
}
/* Helper to convert pthread_t to PyThread_ident_t. POSIX allows pthread_t to be
non-arithmetic, e.g., musl typedefs it as a pointer. */
static PyThread_ident_t
_pthread_t_to_ident(pthread_t value) {
// Cast through an integer type of the same size to avoid sign-extension.
#if SIZEOF_PTHREAD_T == SIZEOF_VOID_P
return (uintptr_t) value;
#elif SIZEOF_PTHREAD_T == SIZEOF_LONG
return (unsigned long) value;
#elif SIZEOF_PTHREAD_T == SIZEOF_INT
return (unsigned int) value;
#elif SIZEOF_PTHREAD_T == SIZEOF_LONG_LONG
return (unsigned long long) value;
#else
#error "Unsupported SIZEOF_PTHREAD_T value"
#endif
}
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 = _pthread_t_to_ident(th);
*handle = (PyThread_handle_t) th;
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);
return (unsigned long) _pthread_t_to_ident(th);;
}
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();
return _pthread_t_to_ident(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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