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bpo-44991: Make GIL handling more explicit in sqlite3 callbacks #27934

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Merged
merged 3 commits into from
Aug 31, 2021
Merged

bpo-44991: Make GIL handling more explicit in sqlite3 callbacks #27934

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e4f4679
Acquire GIL at the very start of callbacks; release at the very end
Aug 24, 2021
2a2152d
Add explanatory comment about mysterious PyErr_Occurred()
Aug 31, 2021
d42eb38
Address review
Aug 31, 2021
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62 changes: 27 additions & 35 deletions Modules/_sqlite/connection.c
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Original file line number Diff line number Diff line change
Expand Up @@ -626,14 +626,12 @@ set_sqlite_error(sqlite3_context *context, const char *msg)
static void
_pysqlite_func_callback(sqlite3_context *context, int argc, sqlite3_value **argv)
{
PyGILState_STATE threadstate = PyGILState_Ensure();

PyObject* args;
PyObject* py_retval = NULL;
int ok;

PyGILState_STATE threadstate;

threadstate = PyGILState_Ensure();

args = _pysqlite_build_py_params(context, argc, argv);
if (args) {
callback_context *ctx = (callback_context *)sqlite3_user_data(context);
Expand All @@ -656,15 +654,13 @@ _pysqlite_func_callback(sqlite3_context *context, int argc, sqlite3_value **argv

static void _pysqlite_step_callback(sqlite3_context *context, int argc, sqlite3_value** params)
{
PyGILState_STATE threadstate = PyGILState_Ensure();

PyObject* args;
PyObject* function_result = NULL;
PyObject** aggregate_instance;
PyObject* stepmethod = NULL;

PyGILState_STATE threadstate;

threadstate = PyGILState_Ensure();

aggregate_instance = (PyObject**)sqlite3_aggregate_context(context, sizeof(PyObject*));

if (*aggregate_instance == NULL) {
Expand Down Expand Up @@ -706,16 +702,14 @@ static void _pysqlite_step_callback(sqlite3_context *context, int argc, sqlite3_
static void
_pysqlite_final_callback(sqlite3_context *context)
{
PyGILState_STATE threadstate = PyGILState_Ensure();

PyObject* function_result;
PyObject** aggregate_instance;
_Py_IDENTIFIER(finalize);
int ok;
PyObject *exception, *value, *tb;

PyGILState_STATE threadstate;

threadstate = PyGILState_Ensure();

aggregate_instance = (PyObject**)sqlite3_aggregate_context(context, 0);
if (aggregate_instance == NULL) {
/* No rows matched the query; the step handler was never called. */
Expand Down Expand Up @@ -787,34 +781,34 @@ static void _pysqlite_drop_unused_cursor_references(pysqlite_Connection* self)
static callback_context *
create_callback_context(pysqlite_state *state, PyObject *callable)
{
PyGILState_STATE gstate = PyGILState_Ensure();
callback_context *ctx = PyMem_Malloc(sizeof(callback_context));
if (ctx != NULL) {
ctx->callable = Py_NewRef(callable);
ctx->state = state;
}
PyGILState_Release(gstate);
return ctx;
}

static void
free_callback_context(callback_context *ctx)
{
assert(ctx != NULL);
Py_DECREF(ctx->callable);
PyMem_Free(ctx);
}

static void
_destructor(void *ctx)
{
if (ctx != NULL) {
// This function may be called without the GIL held, so we need to
// ensure that we destroy 'ctx' with the GIL held.
PyGILState_STATE gstate = PyGILState_Ensure();
Py_DECREF(ctx->callable);
PyMem_Free(ctx);
free_callback_context((callback_context *)ctx);
PyGILState_Release(gstate);
}
}

static void _destructor(void* args)
{
free_callback_context((callback_context *)args);
}

/*[clinic input]
_sqlite3.Connection.create_function as pysqlite_connection_create_function

Expand Down Expand Up @@ -914,11 +908,10 @@ pysqlite_connection_create_aggregate_impl(pysqlite_Connection *self,

static int _authorizer_callback(void* user_arg, int action, const char* arg1, const char* arg2 , const char* dbname, const char* access_attempt_source)
{
PyGILState_STATE gilstate = PyGILState_Ensure();

PyObject *ret;
int rc;
PyGILState_STATE gilstate;

gilstate = PyGILState_Ensure();

ret = PyObject_CallFunction((PyObject*)user_arg, "issss", action, arg1, arg2, dbname, access_attempt_source);

Expand Down Expand Up @@ -959,11 +952,10 @@ static int _authorizer_callback(void* user_arg, int action, const char* arg1, co

static int _progress_handler(void* user_arg)
{
PyGILState_STATE gilstate = PyGILState_Ensure();

int rc;
PyObject *ret;
PyGILState_STATE gilstate;

gilstate = PyGILState_Ensure();
ret = _PyObject_CallNoArg((PyObject*)user_arg);

if (!ret) {
Expand Down Expand Up @@ -1000,18 +992,16 @@ static int _trace_callback(unsigned int type, void* user_arg, void* prepared_sta
static void _trace_callback(void* user_arg, const char* statement_string)
#endif
{
PyObject *py_statement = NULL;
PyObject *ret = NULL;

PyGILState_STATE gilstate;

#ifdef HAVE_TRACE_V2
if (type != SQLITE_TRACE_STMT) {
return 0;
}
#endif

gilstate = PyGILState_Ensure();
PyGILState_STATE gilstate = PyGILState_Ensure();

PyObject *py_statement = NULL;
PyObject *ret = NULL;
py_statement = PyUnicode_DecodeUTF8(statement_string,
strlen(statement_string), "replace");
if (py_statement) {
Expand Down Expand Up @@ -1461,14 +1451,16 @@ pysqlite_collation_callback(
int text1_length, const void* text1_data,
int text2_length, const void* text2_data)
{
PyGILState_STATE gilstate = PyGILState_Ensure();

PyObject* string1 = 0;
PyObject* string2 = 0;
PyGILState_STATE gilstate;
PyObject* retval = NULL;
long longval;
int result = 0;
gilstate = PyGILState_Ensure();

/* This callback may be executed multiple times per sqlite3_step(). Bail if
* the previous call failed */
if (PyErr_Occurred()) {
goto finally;
}
Expand Down