Refactor `_setException()` into different helpers that can be used separately:
- set_ssl_exception_from_errcode(): set an exception from an explicit SSL error code.
- raise_ssl_error(): set an exception from the last SSL error code or use a user-defined message.
- notify_ssl_error_occurred(): same as raise_ssl_error() but with a generic default message.
The PyThreadState field gains a reference count field to avoid
issues with PyThreadState being a dangling pointer to freed memory.
The refcount starts with a value of two: one reference is owned by the
interpreter's linked list of thread states and one reference is owned by
the OS thread. The reference count is decremented when the thread state
is removed from the interpreter's linked list and before the OS thread
calls `PyThread_hang_thread()`. The thread that decrements it to zero
frees the `PyThreadState` memory.
The `holds_gil` field is moved out of the `_status` bit field, to avoid
a data race where on thread calls `PyThreadState_Clear()`, modifying the
`_status` bit field while the OS thread reads `holds_gil` when
attempting to acquire the GIL.
The `PyThreadState.state` field now has `_Py_THREAD_SHUTTING_DOWN` as a
possible value. This corresponds to the `_PyThreadState_MustExit()`
check. This avoids race conditions in the free threading build when
checking `_PyThreadState_MustExit()`.
- Correctly handle `NULL` values returned by `EVP_MD_CTX_md`.
- Correctly free resources in error branches.
- Consistently suppress `_setException()` return value when needed.
- Collapse `_setException() + return NULL` into a single statement.
Move some `#include <stdbool.h>` after `#include "Python.h"` when `pyconfig.h` is not
included first and when we are in a platform-agnostic context. This is to avoid having
features defined by `stdbool.h` before those decided by `Python.h`.
Add two optional, traling elements in the AF_BLUETOOTH socket address tuple:
- l2_cid, to allow e.g raw LE ATT connections
- l2_bdaddr_type. To be able to connect L2CAP sockets to Bluetooth LE devices,
the l2_bdaddr_type must be set to BDADDR_LE_PUBLIC or BDADDR_LE_RANDOM.
The `free_work_item()` function in QSBR may call arbitrary code via
Python object destructors, which may reenter the QSBR code. Reorder
the processing of work items to be robust to reentrancy.
Also fix the TODO for the out of memory situation.
The use of PySys_GetObject() and _PySys_GetAttr(), which return a borrowed
reference, has been replaced by using one of the following functions, which
return a strong reference and distinguish a missing attribute from an error:
_PySys_GetOptionalAttr(), _PySys_GetOptionalAttrString(),
_PySys_GetRequiredAttr(), and _PySys_GetRequiredAttrString().
* Implement C recursion protection with limit pointers for Linux, MacOS and Windows
* Remove calls to PyOS_CheckStack
* Add stack protection to parser
* Make tests more robust to low stacks
* Improve error messages for stack overflow
