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cpython/Include/pythread.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

132 lines
4.7 KiB
C

#ifndef Py_PYTHREAD_H
#define Py_PYTHREAD_H
typedef void *PyThread_type_lock;
#ifdef __cplusplus
extern "C" {
#endif
/* Return status codes for Python lock acquisition. Chosen for maximum
* backwards compatibility, ie failure -> 0, success -> 1. */
typedef enum PyLockStatus {
PY_LOCK_FAILURE = 0,
PY_LOCK_ACQUIRED = 1,
PY_LOCK_INTR
} PyLockStatus;
PyAPI_FUNC(void) PyThread_init_thread(void);
PyAPI_FUNC(unsigned long) PyThread_start_new_thread(void (*)(void *), void *);
/* Terminates the current thread. Considered unsafe.
*
* WARNING: This function is only safe to call if all functions in the full call
* stack are written to safely allow it. Additionally, the behavior is
* platform-dependent. This function should be avoided, and is no longer called
* by Python itself. It is retained only for compatibility with existing C
* extension code.
*
* With pthreads, calls `pthread_exit` causes some libcs (glibc?) to attempt to
* unwind the stack and call C++ destructors; if a `noexcept` function is
* reached, they may terminate the process. Others (macOS) do unwinding.
*
* On Windows, calls `_endthreadex` which kills the thread without calling C++
* destructors.
*
* In either case there is a risk of invalid references remaining to data on the
* thread stack.
*/
Py_DEPRECATED(3.14) PyAPI_FUNC(void) _Py_NO_RETURN PyThread_exit_thread(void);
PyAPI_FUNC(unsigned long) PyThread_get_thread_ident(void);
#if (defined(__APPLE__) || defined(__linux__) || defined(_WIN32) \
|| defined(__FreeBSD__) || defined(__FreeBSD_kernel__) \
|| defined(__OpenBSD__) || defined(__NetBSD__) \
|| defined(__DragonFly__) || defined(_AIX))
#define PY_HAVE_THREAD_NATIVE_ID
PyAPI_FUNC(unsigned long) PyThread_get_thread_native_id(void);
#endif
PyAPI_FUNC(PyThread_type_lock) PyThread_allocate_lock(void);
PyAPI_FUNC(void) PyThread_free_lock(PyThread_type_lock);
PyAPI_FUNC(int) PyThread_acquire_lock(PyThread_type_lock, int);
#define WAIT_LOCK 1
#define NOWAIT_LOCK 0
// PY_TIMEOUT_T is the integral type used to specify timeouts when waiting
// on a lock (see PyThread_acquire_lock_timed() below).
#define PY_TIMEOUT_T long long
/* If microseconds == 0, the call is non-blocking: it returns immediately
even when the lock can't be acquired.
If microseconds > 0, the call waits up to the specified duration.
If microseconds < 0, the call waits until success (or abnormal failure)
If *microseconds* is greater than PY_TIMEOUT_MAX, clamp the timeout to
PY_TIMEOUT_MAX microseconds.
If intr_flag is true and the acquire is interrupted by a signal, then the
call will return PY_LOCK_INTR. The caller may reattempt to acquire the
lock.
*/
PyAPI_FUNC(PyLockStatus) PyThread_acquire_lock_timed(PyThread_type_lock,
PY_TIMEOUT_T microseconds,
int intr_flag);
PyAPI_FUNC(void) PyThread_release_lock(PyThread_type_lock);
PyAPI_FUNC(size_t) PyThread_get_stacksize(void);
PyAPI_FUNC(int) PyThread_set_stacksize(size_t);
#if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 >= 0x03030000
PyAPI_FUNC(PyObject*) PyThread_GetInfo(void);
#endif
/* Thread Local Storage (TLS) API
TLS API is DEPRECATED. Use Thread Specific Storage (TSS) API.
The existing TLS API has used int to represent TLS keys across all
platforms, but it is not POSIX-compliant. Therefore, the new TSS API uses
opaque data type to represent TSS keys to be compatible (see PEP 539).
*/
Py_DEPRECATED(3.7) PyAPI_FUNC(int) PyThread_create_key(void);
Py_DEPRECATED(3.7) PyAPI_FUNC(void) PyThread_delete_key(int key);
Py_DEPRECATED(3.7) PyAPI_FUNC(int) PyThread_set_key_value(int key,
void *value);
Py_DEPRECATED(3.7) PyAPI_FUNC(void *) PyThread_get_key_value(int key);
Py_DEPRECATED(3.7) PyAPI_FUNC(void) PyThread_delete_key_value(int key);
/* Cleanup after a fork */
Py_DEPRECATED(3.7) PyAPI_FUNC(void) PyThread_ReInitTLS(void);
#if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 >= 0x03070000
/* New in 3.7 */
/* Thread Specific Storage (TSS) API */
typedef struct _Py_tss_t Py_tss_t; /* opaque */
PyAPI_FUNC(Py_tss_t *) PyThread_tss_alloc(void);
PyAPI_FUNC(void) PyThread_tss_free(Py_tss_t *key);
/* The parameter key must not be NULL. */
PyAPI_FUNC(int) PyThread_tss_is_created(Py_tss_t *key);
PyAPI_FUNC(int) PyThread_tss_create(Py_tss_t *key);
PyAPI_FUNC(void) PyThread_tss_delete(Py_tss_t *key);
PyAPI_FUNC(int) PyThread_tss_set(Py_tss_t *key, void *value);
PyAPI_FUNC(void *) PyThread_tss_get(Py_tss_t *key);
#endif /* New in 3.7 */
#ifndef Py_LIMITED_API
# define Py_CPYTHON_PYTHREAD_H
# include "cpython/pythread.h"
# undef Py_CPYTHON_PYTHREAD_H
#endif
#ifdef __cplusplus
}
#endif
#endif /* !Py_PYTHREAD_H */