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pystate.c
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3188 lines (2706 loc) · 91.5 KB
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/* Thread and interpreter state structures and their interfaces */
#include "Python.h"
#include "pycore_ceval.h"
#include "pycore_code.h" // stats
#include "pycore_dtoa.h" // _dtoa_state_INIT()
#include "pycore_emscripten_trampoline.h" // _Py_EmscriptenTrampoline_Init()
#include "pycore_frame.h"
#include "pycore_initconfig.h" // _PyStatus_OK()
#include "pycore_object.h" // _PyType_InitCache()
#include "pycore_parking_lot.h" // _PyParkingLot_AfterFork()
#include "pycore_pyerrors.h" // _PyErr_Clear()
#include "pycore_pylifecycle.h" // _PyAST_Fini()
#include "pycore_pymem.h" // _PyMem_SetDefaultAllocator()
#include "pycore_pystate.h"
#include "pycore_runtime_init.h" // _PyRuntimeState_INIT
#include "pycore_sysmodule.h" // _PySys_Audit()
#include "pycore_weakref.h" // _PyWeakref_GET_REF()
/* --------------------------------------------------------------------------
CAUTION
Always use PyMem_RawMalloc() and PyMem_RawFree() directly in this file. A
number of these functions are advertised as safe to call when the GIL isn't
held, and in a debug build Python redirects (e.g.) PyMem_NEW (etc) to Python's
debugging obmalloc functions. Those aren't thread-safe (they rely on the GIL
to avoid the expense of doing their own locking).
-------------------------------------------------------------------------- */
#ifdef HAVE_DLOPEN
# ifdef HAVE_DLFCN_H
# include <dlfcn.h>
# endif
# if !HAVE_DECL_RTLD_LAZY
# define RTLD_LAZY 1
# endif
#endif
/****************************************/
/* helpers for the current thread state */
/****************************************/
// API for the current thread state is further down.
/* "current" means one of:
- bound to the current OS thread
- holds the GIL
*/
//-------------------------------------------------
// a highly efficient lookup for the current thread
//-------------------------------------------------
/*
The stored thread state is set by PyThreadState_Swap().
For each of these functions, the GIL must be held by the current thread.
*/
#ifdef HAVE_THREAD_LOCAL
_Py_thread_local PyThreadState *_Py_tss_tstate = NULL;
#endif
static inline PyThreadState *
current_fast_get(_PyRuntimeState *Py_UNUSED(runtime))
{
#ifdef HAVE_THREAD_LOCAL
return _Py_tss_tstate;
#else
// XXX Fall back to the PyThread_tss_*() API.
# error "no supported thread-local variable storage classifier"
#endif
}
static inline void
current_fast_set(_PyRuntimeState *Py_UNUSED(runtime), PyThreadState *tstate)
{
assert(tstate != NULL);
#ifdef HAVE_THREAD_LOCAL
_Py_tss_tstate = tstate;
#else
// XXX Fall back to the PyThread_tss_*() API.
# error "no supported thread-local variable storage classifier"
#endif
}
static inline void
current_fast_clear(_PyRuntimeState *Py_UNUSED(runtime))
{
#ifdef HAVE_THREAD_LOCAL
_Py_tss_tstate = NULL;
#else
// XXX Fall back to the PyThread_tss_*() API.
# error "no supported thread-local variable storage classifier"
#endif
}
#define tstate_verify_not_active(tstate) \
if (tstate == current_fast_get((tstate)->interp->runtime)) { \
_Py_FatalErrorFormat(__func__, "tstate %p is still current", tstate); \
}
PyThreadState *
_PyThreadState_GetCurrent(void)
{
return current_fast_get(&_PyRuntime);
}
//------------------------------------------------
// the thread state bound to the current OS thread
//------------------------------------------------
static inline int
tstate_tss_initialized(Py_tss_t *key)
{
return PyThread_tss_is_created(key);
}
static inline int
tstate_tss_init(Py_tss_t *key)
{
assert(!tstate_tss_initialized(key));
return PyThread_tss_create(key);
}
static inline void
tstate_tss_fini(Py_tss_t *key)
{
assert(tstate_tss_initialized(key));
PyThread_tss_delete(key);
}
static inline PyThreadState *
tstate_tss_get(Py_tss_t *key)
{
assert(tstate_tss_initialized(key));
return (PyThreadState *)PyThread_tss_get(key);
}
static inline int
tstate_tss_set(Py_tss_t *key, PyThreadState *tstate)
{
assert(tstate != NULL);
assert(tstate_tss_initialized(key));
return PyThread_tss_set(key, (void *)tstate);
}
static inline int
tstate_tss_clear(Py_tss_t *key)
{
assert(tstate_tss_initialized(key));
return PyThread_tss_set(key, (void *)NULL);
}
#ifdef HAVE_FORK
/* Reset the TSS key - called by PyOS_AfterFork_Child().
* This should not be necessary, but some - buggy - pthread implementations
* don't reset TSS upon fork(), see issue #10517.
*/
static PyStatus
tstate_tss_reinit(Py_tss_t *key)
{
if (!tstate_tss_initialized(key)) {
return _PyStatus_OK();
}
PyThreadState *tstate = tstate_tss_get(key);
tstate_tss_fini(key);
if (tstate_tss_init(key) != 0) {
return _PyStatus_NO_MEMORY();
}
/* If the thread had an associated auto thread state, reassociate it with
* the new key. */
if (tstate && tstate_tss_set(key, tstate) != 0) {
return _PyStatus_ERR("failed to re-set autoTSSkey");
}
return _PyStatus_OK();
}
#endif
/*
The stored thread state is set by bind_tstate() (AKA PyThreadState_Bind().
The GIL does no need to be held for these.
*/
#define gilstate_tss_initialized(runtime) \
tstate_tss_initialized(&(runtime)->autoTSSkey)
#define gilstate_tss_init(runtime) \
tstate_tss_init(&(runtime)->autoTSSkey)
#define gilstate_tss_fini(runtime) \
tstate_tss_fini(&(runtime)->autoTSSkey)
#define gilstate_tss_get(runtime) \
tstate_tss_get(&(runtime)->autoTSSkey)
#define _gilstate_tss_set(runtime, tstate) \
tstate_tss_set(&(runtime)->autoTSSkey, tstate)
#define _gilstate_tss_clear(runtime) \
tstate_tss_clear(&(runtime)->autoTSSkey)
#define gilstate_tss_reinit(runtime) \
tstate_tss_reinit(&(runtime)->autoTSSkey)
static inline void
gilstate_tss_set(_PyRuntimeState *runtime, PyThreadState *tstate)
{
assert(tstate != NULL && tstate->interp->runtime == runtime);
if (_gilstate_tss_set(runtime, tstate) != 0) {
Py_FatalError("failed to set current tstate (TSS)");
}
}
static inline void
gilstate_tss_clear(_PyRuntimeState *runtime)
{
if (_gilstate_tss_clear(runtime) != 0) {
Py_FatalError("failed to clear current tstate (TSS)");
}
}
#ifndef NDEBUG
static inline int tstate_is_alive(PyThreadState *tstate);
static inline int
tstate_is_bound(PyThreadState *tstate)
{
return tstate->_status.bound && !tstate->_status.unbound;
}
#endif // !NDEBUG
static void bind_gilstate_tstate(PyThreadState *);
static void unbind_gilstate_tstate(PyThreadState *);
static void
bind_tstate(PyThreadState *tstate)
{
assert(tstate != NULL);
assert(tstate_is_alive(tstate) && !tstate->_status.bound);
assert(!tstate->_status.unbound); // just in case
assert(!tstate->_status.bound_gilstate);
assert(tstate != gilstate_tss_get(tstate->interp->runtime));
assert(!tstate->_status.active);
assert(tstate->thread_id == 0);
assert(tstate->native_thread_id == 0);
// Currently we don't necessarily store the thread state
// in thread-local storage (e.g. per-interpreter).
tstate->thread_id = PyThread_get_thread_ident();
#ifdef PY_HAVE_THREAD_NATIVE_ID
tstate->native_thread_id = PyThread_get_thread_native_id();
#endif
tstate->_status.bound = 1;
}
static void
unbind_tstate(PyThreadState *tstate)
{
assert(tstate != NULL);
assert(tstate_is_bound(tstate));
#ifndef HAVE_PTHREAD_STUBS
assert(tstate->thread_id > 0);
#endif
#ifdef PY_HAVE_THREAD_NATIVE_ID
assert(tstate->native_thread_id > 0);
#endif
// We leave thread_id and native_thread_id alone
// since they can be useful for debugging.
// Check the `_status` field to know if these values
// are still valid.
// We leave tstate->_status.bound set to 1
// to indicate it was previously bound.
tstate->_status.unbound = 1;
}
/* Stick the thread state for this thread in thread specific storage.
When a thread state is created for a thread by some mechanism
other than PyGILState_Ensure(), it's important that the GILState
machinery knows about it so it doesn't try to create another
thread state for the thread.
(This is a better fix for SF bug #1010677 than the first one attempted.)
The only situation where you can legitimately have more than one
thread state for an OS level thread is when there are multiple
interpreters.
Before 3.12, the PyGILState_*() APIs didn't work with multiple
interpreters (see bpo-10915 and bpo-15751), so this function used
to set TSS only once. Thus, the first thread state created for that
given OS level thread would "win", which seemed reasonable behaviour.
*/
static void
bind_gilstate_tstate(PyThreadState *tstate)
{
assert(tstate != NULL);
assert(tstate_is_alive(tstate));
assert(tstate_is_bound(tstate));
// XXX assert(!tstate->_status.active);
assert(!tstate->_status.bound_gilstate);
_PyRuntimeState *runtime = tstate->interp->runtime;
PyThreadState *tcur = gilstate_tss_get(runtime);
assert(tstate != tcur);
if (tcur != NULL) {
tcur->_status.bound_gilstate = 0;
}
gilstate_tss_set(runtime, tstate);
tstate->_status.bound_gilstate = 1;
}
static void
unbind_gilstate_tstate(PyThreadState *tstate)
{
assert(tstate != NULL);
// XXX assert(tstate_is_alive(tstate));
assert(tstate_is_bound(tstate));
// XXX assert(!tstate->_status.active);
assert(tstate->_status.bound_gilstate);
assert(tstate == gilstate_tss_get(tstate->interp->runtime));
gilstate_tss_clear(tstate->interp->runtime);
tstate->_status.bound_gilstate = 0;
}
//----------------------------------------------
// the thread state that currently holds the GIL
//----------------------------------------------
/* This is not exported, as it is not reliable! It can only
ever be compared to the state for the *current* thread.
* If not equal, then it doesn't matter that the actual
value may change immediately after comparison, as it can't
possibly change to the current thread's state.
* If equal, then the current thread holds the lock, so the value can't
change until we yield the lock.
*/
static int
holds_gil(PyThreadState *tstate)
{
// XXX Fall back to tstate->interp->runtime->ceval.gil.last_holder
// (and tstate->interp->runtime->ceval.gil.locked).
assert(tstate != NULL);
_PyRuntimeState *runtime = tstate->interp->runtime;
/* Must be the tstate for this thread */
assert(tstate == gilstate_tss_get(runtime));
return tstate == current_fast_get(runtime);
}
/****************************/
/* the global runtime state */
/****************************/
//----------
// lifecycle
//----------
/* Suppress deprecation warning for PyBytesObject.ob_shash */
_Py_COMP_DIAG_PUSH
_Py_COMP_DIAG_IGNORE_DEPR_DECLS
/* We use "initial" if the runtime gets re-used
(e.g. Py_Finalize() followed by Py_Initialize().
Note that we initialize "initial" relative to _PyRuntime,
to ensure pre-initialized pointers point to the active
runtime state (and not "initial"). */
static const _PyRuntimeState initial = _PyRuntimeState_INIT(_PyRuntime);
_Py_COMP_DIAG_POP
#define NUMLOCKS 9
#define LOCKS_INIT(runtime) \
{ \
&(runtime)->interpreters.mutex, \
&(runtime)->xidregistry.mutex, \
&(runtime)->getargs.mutex, \
&(runtime)->unicode_state.ids.lock, \
&(runtime)->imports.extensions.mutex, \
&(runtime)->ceval.pending_mainthread.lock, \
&(runtime)->atexit.mutex, \
&(runtime)->audit_hooks.mutex, \
&(runtime)->allocators.mutex, \
}
static int
alloc_for_runtime(PyThread_type_lock locks[NUMLOCKS])
{
/* Force default allocator, since _PyRuntimeState_Fini() must
use the same allocator than this function. */
PyMemAllocatorEx old_alloc;
_PyMem_SetDefaultAllocator(PYMEM_DOMAIN_RAW, &old_alloc);
for (int i = 0; i < NUMLOCKS; i++) {
PyThread_type_lock lock = PyThread_allocate_lock();
if (lock == NULL) {
for (int j = 0; j < i; j++) {
PyThread_free_lock(locks[j]);
locks[j] = NULL;
}
break;
}
locks[i] = lock;
}
PyMem_SetAllocator(PYMEM_DOMAIN_RAW, &old_alloc);
return 0;
}
static void
init_runtime(_PyRuntimeState *runtime,
void *open_code_hook, void *open_code_userdata,
_Py_AuditHookEntry *audit_hook_head,
Py_ssize_t unicode_next_index,
PyThread_type_lock locks[NUMLOCKS])
{
assert(!runtime->preinitializing);
assert(!runtime->preinitialized);
assert(!runtime->core_initialized);
assert(!runtime->initialized);
assert(!runtime->_initialized);
runtime->open_code_hook = open_code_hook;
runtime->open_code_userdata = open_code_userdata;
runtime->audit_hooks.head = audit_hook_head;
PyPreConfig_InitPythonConfig(&runtime->preconfig);
PyThread_type_lock *lockptrs[NUMLOCKS] = LOCKS_INIT(runtime);
for (int i = 0; i < NUMLOCKS; i++) {
assert(locks[i] != NULL);
*lockptrs[i] = locks[i];
}
// Set it to the ID of the main thread of the main interpreter.
runtime->main_thread = PyThread_get_thread_ident();
runtime->unicode_state.ids.next_index = unicode_next_index;
#if defined(__EMSCRIPTEN__) && defined(PY_CALL_TRAMPOLINE)
_Py_EmscriptenTrampoline_Init(runtime);
#endif
runtime->_initialized = 1;
}
PyStatus
_PyRuntimeState_Init(_PyRuntimeState *runtime)
{
/* We preserve the hook across init, because there is
currently no public API to set it between runtime
initialization and interpreter initialization. */
void *open_code_hook = runtime->open_code_hook;
void *open_code_userdata = runtime->open_code_userdata;
_Py_AuditHookEntry *audit_hook_head = runtime->audit_hooks.head;
// bpo-42882: Preserve next_index value if Py_Initialize()/Py_Finalize()
// is called multiple times.
Py_ssize_t unicode_next_index = runtime->unicode_state.ids.next_index;
PyThread_type_lock locks[NUMLOCKS];
if (alloc_for_runtime(locks) != 0) {
return _PyStatus_NO_MEMORY();
}
if (runtime->_initialized) {
// Py_Initialize() must be running again.
// Reset to _PyRuntimeState_INIT.
memcpy(runtime, &initial, sizeof(*runtime));
assert(!runtime->_initialized);
}
if (gilstate_tss_init(runtime) != 0) {
_PyRuntimeState_Fini(runtime);
return _PyStatus_NO_MEMORY();
}
if (PyThread_tss_create(&runtime->trashTSSkey) != 0) {
_PyRuntimeState_Fini(runtime);
return _PyStatus_NO_MEMORY();
}
init_runtime(runtime, open_code_hook, open_code_userdata, audit_hook_head,
unicode_next_index, locks);
return _PyStatus_OK();
}
static void _xidregistry_clear(struct _xidregistry *);
void
_PyRuntimeState_Fini(_PyRuntimeState *runtime)
{
#ifdef Py_REF_DEBUG
/* The count is cleared by _Py_FinalizeRefTotal(). */
assert(runtime->object_state.interpreter_leaks == 0);
#endif
_xidregistry_clear(&runtime->xidregistry);
if (gilstate_tss_initialized(runtime)) {
gilstate_tss_fini(runtime);
}
if (PyThread_tss_is_created(&runtime->trashTSSkey)) {
PyThread_tss_delete(&runtime->trashTSSkey);
}
/* Force the allocator used by _PyRuntimeState_Init(). */
PyMemAllocatorEx old_alloc;
_PyMem_SetDefaultAllocator(PYMEM_DOMAIN_RAW, &old_alloc);
#define FREE_LOCK(LOCK) \
if (LOCK != NULL) { \
PyThread_free_lock(LOCK); \
LOCK = NULL; \
}
PyThread_type_lock *lockptrs[NUMLOCKS] = LOCKS_INIT(runtime);
for (int i = 0; i < NUMLOCKS; i++) {
FREE_LOCK(*lockptrs[i]);
}
#undef FREE_LOCK
PyMem_SetAllocator(PYMEM_DOMAIN_RAW, &old_alloc);
}
#ifdef HAVE_FORK
/* This function is called from PyOS_AfterFork_Child to ensure that
newly created child processes do not share locks with the parent. */
PyStatus
_PyRuntimeState_ReInitThreads(_PyRuntimeState *runtime)
{
// This was initially set in _PyRuntimeState_Init().
runtime->main_thread = PyThread_get_thread_ident();
/* Force default allocator, since _PyRuntimeState_Fini() must
use the same allocator than this function. */
PyMemAllocatorEx old_alloc;
_PyMem_SetDefaultAllocator(PYMEM_DOMAIN_RAW, &old_alloc);
PyThread_type_lock *lockptrs[NUMLOCKS] = LOCKS_INIT(runtime);
int reinit_err = 0;
for (int i = 0; i < NUMLOCKS; i++) {
reinit_err += _PyThread_at_fork_reinit(lockptrs[i]);
}
/* PyOS_AfterFork_Child(), which calls this function, later calls
_PyInterpreterState_DeleteExceptMain(), so we only need to update
the main interpreter here. */
assert(runtime->interpreters.main != NULL);
runtime->interpreters.main->xidregistry.mutex = runtime->xidregistry.mutex;
PyMem_SetAllocator(PYMEM_DOMAIN_RAW, &old_alloc);
// Clears the parking lot. Any waiting threads are dead. This must be
// called before releasing any locks that use the parking lot.
_PyParkingLot_AfterFork();
/* bpo-42540: id_mutex is freed by _PyInterpreterState_Delete, which does
* not force the default allocator. */
reinit_err += _PyThread_at_fork_reinit(&runtime->interpreters.main->id_mutex);
if (reinit_err < 0) {
return _PyStatus_ERR("Failed to reinitialize runtime locks");
}
PyStatus status = gilstate_tss_reinit(runtime);
if (_PyStatus_EXCEPTION(status)) {
return status;
}
if (PyThread_tss_is_created(&runtime->trashTSSkey)) {
PyThread_tss_delete(&runtime->trashTSSkey);
}
if (PyThread_tss_create(&runtime->trashTSSkey) != 0) {
return _PyStatus_NO_MEMORY();
}
return _PyStatus_OK();
}
#endif
/*************************************/
/* the per-interpreter runtime state */
/*************************************/
//----------
// lifecycle
//----------
/* Calling this indicates that the runtime is ready to create interpreters. */
PyStatus
_PyInterpreterState_Enable(_PyRuntimeState *runtime)
{
struct pyinterpreters *interpreters = &runtime->interpreters;
interpreters->next_id = 0;
/* Py_Finalize() calls _PyRuntimeState_Fini() which clears the mutex.
Create a new mutex if needed. */
if (interpreters->mutex == NULL) {
/* Force default allocator, since _PyRuntimeState_Fini() must
use the same allocator than this function. */
PyMemAllocatorEx old_alloc;
_PyMem_SetDefaultAllocator(PYMEM_DOMAIN_RAW, &old_alloc);
interpreters->mutex = PyThread_allocate_lock();
PyMem_SetAllocator(PYMEM_DOMAIN_RAW, &old_alloc);
if (interpreters->mutex == NULL) {
return _PyStatus_ERR("Can't initialize threads for interpreter");
}
}
return _PyStatus_OK();
}
static PyInterpreterState *
alloc_interpreter(void)
{
return PyMem_RawCalloc(1, sizeof(PyInterpreterState));
}
static void
free_interpreter(PyInterpreterState *interp)
{
// The main interpreter is statically allocated so
// should not be freed.
if (interp != &_PyRuntime._main_interpreter) {
PyMem_RawFree(interp);
}
}
/* Get the interpreter state to a minimal consistent state.
Further init happens in pylifecycle.c before it can be used.
All fields not initialized here are expected to be zeroed out,
e.g. by PyMem_RawCalloc() or memset(), or otherwise pre-initialized.
The runtime state is not manipulated. Instead it is assumed that
the interpreter is getting added to the runtime.
Note that the main interpreter was statically initialized as part
of the runtime and most state is already set properly. That leaves
a small number of fields to initialize dynamically, as well as some
that are initialized lazily.
For subinterpreters we memcpy() the main interpreter in
PyInterpreterState_New(), leaving it in the same mostly-initialized
state. The only difference is that the interpreter has some
self-referential state that is statically initializexd to the
main interpreter. We fix those fields here, in addition
to the other dynamically initialized fields.
*/
static PyStatus
init_interpreter(PyInterpreterState *interp,
_PyRuntimeState *runtime, int64_t id,
PyInterpreterState *next,
PyThread_type_lock pending_lock)
{
if (interp->_initialized) {
return _PyStatus_ERR("interpreter already initialized");
}
assert(runtime != NULL);
interp->runtime = runtime;
assert(id > 0 || (id == 0 && interp == runtime->interpreters.main));
interp->id = id;
assert(runtime->interpreters.head == interp);
assert(next != NULL || (interp == runtime->interpreters.main));
interp->next = next;
/* Initialize obmalloc, but only for subinterpreters,
since the main interpreter is initialized statically. */
if (interp != &runtime->_main_interpreter) {
poolp temp[OBMALLOC_USED_POOLS_SIZE] = \
_obmalloc_pools_INIT(interp->obmalloc.pools);
memcpy(&interp->obmalloc.pools.used, temp, sizeof(temp));
}
PyStatus status = _PyObject_InitState(interp);
if (_PyStatus_EXCEPTION(status)) {
return status;
}
_PyEval_InitState(interp, pending_lock);
_PyGC_InitState(&interp->gc);
PyConfig_InitPythonConfig(&interp->config);
_PyType_InitCache(interp);
for (int i = 0; i < _PY_MONITORING_UNGROUPED_EVENTS; i++) {
interp->monitors.tools[i] = 0;
}
for (int t = 0; t < PY_MONITORING_TOOL_IDS; t++) {
for (int e = 0; e < _PY_MONITORING_EVENTS; e++) {
interp->monitoring_callables[t][e] = NULL;
}
}
interp->sys_profile_initialized = false;
interp->sys_trace_initialized = false;
interp->optimizer = &_PyOptimizer_Default;
interp->optimizer_backedge_threshold = _PyOptimizer_Default.backedge_threshold;
interp->optimizer_resume_threshold = _PyOptimizer_Default.backedge_threshold;
interp->next_func_version = 1;
interp->executor_list_head = NULL;
if (interp != &runtime->_main_interpreter) {
/* Fix the self-referential, statically initialized fields. */
interp->dtoa = (struct _dtoa_state)_dtoa_state_INIT(interp);
}
interp->f_opcode_trace_set = false;
assert(runtime->xidregistry.mutex != NULL);
interp->xidregistry.mutex = runtime->xidregistry.mutex;
interp->_initialized = 1;
return _PyStatus_OK();
}
PyStatus
_PyInterpreterState_New(PyThreadState *tstate, PyInterpreterState **pinterp)
{
*pinterp = NULL;
// Don't get runtime from tstate since tstate can be NULL
_PyRuntimeState *runtime = &_PyRuntime;
// tstate is NULL when pycore_create_interpreter() calls
// _PyInterpreterState_New() to create the main interpreter.
if (tstate != NULL) {
if (_PySys_Audit(tstate, "cpython.PyInterpreterState_New", NULL) < 0) {
return _PyStatus_ERR("sys.audit failed");
}
}
PyThread_type_lock pending_lock = PyThread_allocate_lock();
if (pending_lock == NULL) {
return _PyStatus_NO_MEMORY();
}
/* We completely serialize creation of multiple interpreters, since
it simplifies things here and blocking concurrent calls isn't a problem.
Regardless, we must fully block subinterpreter creation until
after the main interpreter is created. */
HEAD_LOCK(runtime);
struct pyinterpreters *interpreters = &runtime->interpreters;
int64_t id = interpreters->next_id;
interpreters->next_id += 1;
// Allocate the interpreter and add it to the runtime state.
PyInterpreterState *interp;
PyStatus status;
PyInterpreterState *old_head = interpreters->head;
if (old_head == NULL) {
// We are creating the main interpreter.
assert(interpreters->main == NULL);
assert(id == 0);
interp = &runtime->_main_interpreter;
assert(interp->id == 0);
assert(interp->next == NULL);
interpreters->main = interp;
}
else {
assert(interpreters->main != NULL);
assert(id != 0);
interp = alloc_interpreter();
if (interp == NULL) {
status = _PyStatus_NO_MEMORY();
goto error;
}
// Set to _PyInterpreterState_INIT.
memcpy(interp, &initial._main_interpreter, sizeof(*interp));
if (id < 0) {
/* overflow or Py_Initialize() not called yet! */
status = _PyStatus_ERR("failed to get an interpreter ID");
goto error;
}
}
interpreters->head = interp;
status = init_interpreter(interp, runtime,
id, old_head, pending_lock);
if (_PyStatus_EXCEPTION(status)) {
goto error;
}
pending_lock = NULL;
HEAD_UNLOCK(runtime);
assert(interp != NULL);
*pinterp = interp;
return _PyStatus_OK();
error:
HEAD_UNLOCK(runtime);
if (pending_lock != NULL) {
PyThread_free_lock(pending_lock);
}
if (interp != NULL) {
free_interpreter(interp);
}
return status;
}
PyInterpreterState *
PyInterpreterState_New(void)
{
// tstate can be NULL
PyThreadState *tstate = current_fast_get(&_PyRuntime);
PyInterpreterState *interp;
PyStatus status = _PyInterpreterState_New(tstate, &interp);
if (_PyStatus_EXCEPTION(status)) {
Py_ExitStatusException(status);
}
assert(interp != NULL);
return interp;
}
static void
interpreter_clear(PyInterpreterState *interp, PyThreadState *tstate)
{
assert(interp != NULL);
assert(tstate != NULL);
_PyRuntimeState *runtime = interp->runtime;
/* XXX Conditions we need to enforce:
* the GIL must be held by the current thread
* tstate must be the "current" thread state (current_fast_get())
* tstate->interp must be interp
* for the main interpreter, tstate must be the main thread
*/
// XXX Ideally, we would not rely on any thread state in this function
// (and we would drop the "tstate" argument).
if (_PySys_Audit(tstate, "cpython.PyInterpreterState_Clear", NULL) < 0) {
_PyErr_Clear(tstate);
}
// Clear the current/main thread state last.
HEAD_LOCK(runtime);
PyThreadState *p = interp->threads.head;
HEAD_UNLOCK(runtime);
while (p != NULL) {
// See https://github.com/python/cpython/issues/102126
// Must be called without HEAD_LOCK held as it can deadlock
// if any finalizer tries to acquire that lock.
PyThreadState_Clear(p);
HEAD_LOCK(runtime);
p = p->next;
HEAD_UNLOCK(runtime);
}
if (tstate->interp == interp) {
/* We fix tstate->_status below when we for sure aren't using it
(e.g. no longer need the GIL). */
// XXX Eliminate the need to do this.
tstate->_status.cleared = 0;
}
Py_CLEAR(interp->optimizer);
interp->optimizer = &_PyOptimizer_Default;
interp->optimizer_backedge_threshold = _PyOptimizer_Default.backedge_threshold;
interp->optimizer_resume_threshold = _PyOptimizer_Default.backedge_threshold;
/* It is possible that any of the objects below have a finalizer
that runs Python code or otherwise relies on a thread state
or even the interpreter state. For now we trust that isn't
a problem.
*/
// XXX Make sure we properly deal with problematic finalizers.
Py_CLEAR(interp->audit_hooks);
// At this time, all the threads should be cleared so we don't need
// atomic operations for eval_breaker
interp->ceval.eval_breaker = 0;
for (int i = 0; i < _PY_MONITORING_UNGROUPED_EVENTS; i++) {
interp->monitors.tools[i] = 0;
}
for (int t = 0; t < PY_MONITORING_TOOL_IDS; t++) {
for (int e = 0; e < _PY_MONITORING_EVENTS; e++) {
Py_CLEAR(interp->monitoring_callables[t][e]);
}
}
interp->sys_profile_initialized = false;
interp->sys_trace_initialized = false;
for (int t = 0; t < PY_MONITORING_TOOL_IDS; t++) {
Py_CLEAR(interp->monitoring_tool_names[t]);
}
PyConfig_Clear(&interp->config);
Py_CLEAR(interp->codec_search_path);
Py_CLEAR(interp->codec_search_cache);
Py_CLEAR(interp->codec_error_registry);
assert(interp->imports.modules == NULL);
assert(interp->imports.modules_by_index == NULL);
assert(interp->imports.importlib == NULL);
assert(interp->imports.import_func == NULL);
Py_CLEAR(interp->sysdict_copy);
Py_CLEAR(interp->builtins_copy);
Py_CLEAR(interp->dict);
#ifdef HAVE_FORK
Py_CLEAR(interp->before_forkers);
Py_CLEAR(interp->after_forkers_parent);
Py_CLEAR(interp->after_forkers_child);
#endif
_PyAST_Fini(interp);
_PyWarnings_Fini(interp);
_PyAtExit_Fini(interp);
// All Python types must be destroyed before the last GC collection. Python
// types create a reference cycle to themselves in their in their
// PyTypeObject.tp_mro member (the tuple contains the type).
/* Last garbage collection on this interpreter */
_PyGC_CollectNoFail(tstate);
_PyGC_Fini(interp);
/* We don't clear sysdict and builtins until the end of this function.
Because clearing other attributes can execute arbitrary Python code
which requires sysdict and builtins. */
PyDict_Clear(interp->sysdict);
PyDict_Clear(interp->builtins);
Py_CLEAR(interp->sysdict);
Py_CLEAR(interp->builtins);
_xidregistry_clear(&interp->xidregistry);
/* The lock is owned by the runtime, so we don't free it here. */
interp->xidregistry.mutex = NULL;
if (tstate->interp == interp) {
/* We are now safe to fix tstate->_status.cleared. */
// XXX Do this (much) earlier?
tstate->_status.cleared = 1;
}
for (int i=0; i < DICT_MAX_WATCHERS; i++) {
interp->dict_state.watchers[i] = NULL;
}
for (int i=0; i < TYPE_MAX_WATCHERS; i++) {
interp->type_watchers[i] = NULL;
}
for (int i=0; i < FUNC_MAX_WATCHERS; i++) {
interp->func_watchers[i] = NULL;
}
interp->active_func_watchers = 0;
for (int i=0; i < CODE_MAX_WATCHERS; i++) {
interp->code_watchers[i] = NULL;
}
interp->active_code_watchers = 0;
interp->f_opcode_trace_set = false;
// XXX Once we have one allocator per interpreter (i.e.
// per-interpreter GC) we must ensure that all of the interpreter's
// objects have been cleaned up at the point.
}
void
PyInterpreterState_Clear(PyInterpreterState *interp)
{
// Use the current Python thread state to call audit hooks and to collect
// garbage. It can be different than the current Python thread state
// of 'interp'.
PyThreadState *current_tstate = current_fast_get(interp->runtime);
_PyImport_ClearCore(interp);
interpreter_clear(interp, current_tstate);
}
void
_PyInterpreterState_Clear(PyThreadState *tstate)
{
_PyImport_ClearCore(tstate->interp);