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https://github.com/python/cpython
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2e5d8a90aa
This matches the GIL releasing behavior of our existing `_hashopenssl` module, extending it to the HACL* built-ins. Includes adding comments to better describe the ENTER/LEAVE macros purpose and explain the lock strategy in both existing and new code.
67 lines
2.5 KiB
C
67 lines
2.5 KiB
C
/* Common code for use by all hashlib related modules. */
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/*
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* Given a PyObject* obj, fill in the Py_buffer* viewp with the result
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* of PyObject_GetBuffer. Sets an exception and issues the erraction
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* on any errors, e.g. 'return NULL' or 'goto error'.
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*/
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#define GET_BUFFER_VIEW_OR_ERROR(obj, viewp, erraction) do { \
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if (PyUnicode_Check((obj))) { \
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PyErr_SetString(PyExc_TypeError, \
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"Strings must be encoded before hashing");\
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erraction; \
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} \
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if (!PyObject_CheckBuffer((obj))) { \
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PyErr_SetString(PyExc_TypeError, \
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"object supporting the buffer API required"); \
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erraction; \
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} \
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if (PyObject_GetBuffer((obj), (viewp), PyBUF_SIMPLE) == -1) { \
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erraction; \
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} \
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if ((viewp)->ndim > 1) { \
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PyErr_SetString(PyExc_BufferError, \
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"Buffer must be single dimension"); \
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PyBuffer_Release((viewp)); \
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erraction; \
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} \
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} while(0)
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#define GET_BUFFER_VIEW_OR_ERROUT(obj, viewp) \
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GET_BUFFER_VIEW_OR_ERROR(obj, viewp, return NULL)
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/*
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* Helper code to synchronize access to the hash object when the GIL is
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* released around a CPU consuming hashlib operation. All code paths that
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* access a mutable part of obj must be enclosed in an ENTER_HASHLIB /
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* LEAVE_HASHLIB block or explicitly acquire and release the lock inside
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* a PY_BEGIN / END_ALLOW_THREADS block if they wish to release the GIL for
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* an operation.
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*
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* These only drop the GIL if the lock acquisition itself is likely to
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* block. Thus the non-blocking acquire gating the GIL release for a
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* blocking lock acquisition. The intent of these macros is to surround
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* the assumed always "fast" operations that you aren't releasing the
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* GIL around. Otherwise use code similar to what you see in hash
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* function update() methods.
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*/
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#include "pythread.h"
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#define ENTER_HASHLIB(obj) \
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if ((obj)->lock) { \
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if (!PyThread_acquire_lock((obj)->lock, 0)) { \
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Py_BEGIN_ALLOW_THREADS \
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PyThread_acquire_lock((obj)->lock, 1); \
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Py_END_ALLOW_THREADS \
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} \
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}
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#define LEAVE_HASHLIB(obj) \
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if ((obj)->lock) { \
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PyThread_release_lock((obj)->lock); \
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}
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/* TODO(gpshead): We should make this a module or class attribute
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* to allow the user to optimize based on the platform they're using. */
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#define HASHLIB_GIL_MINSIZE 2048
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