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cpython/Python/crossinterp.c

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/* API for managing interactions between isolated interpreters */
#include "Python.h"
#include "marshal.h" // PyMarshal_WriteObjectToString()
#include "osdefs.h" // MAXPATHLEN
#include "pycore_ceval.h" // _Py_simple_func
#include "pycore_crossinterp.h" // _PyXIData_t
#include "pycore_function.h" // _PyFunction_VerifyStateless()
#include "pycore_global_strings.h" // _Py_ID()
#include "pycore_import.h" // _PyImport_SetModule()
#include "pycore_initconfig.h" // _PyStatus_OK()
#include "pycore_namespace.h" // _PyNamespace_New()
#include "pycore_pythonrun.h" // _Py_SourceAsString()
#include "pycore_runtime.h" // _PyRuntime
#include "pycore_setobject.h" // _PySet_NextEntry()
#include "pycore_typeobject.h" // _PyStaticType_InitBuiltin()
static Py_ssize_t
_Py_GetMainfile(char *buffer, size_t maxlen)
{
// We don't expect subinterpreters to have the __main__ module's
// __name__ set, but proceed just in case.
PyThreadState *tstate = _PyThreadState_GET();
PyObject *module = _Py_GetMainModule(tstate);
if (_Py_CheckMainModule(module) < 0) {
Py_XDECREF(module);
return -1;
}
Py_ssize_t size = _PyModule_GetFilenameUTF8(module, buffer, maxlen);
Py_DECREF(module);
return size;
}
static PyObject *
runpy_run_path(const char *filename, const char *modname)
{
PyObject *run_path = PyImport_ImportModuleAttrString("runpy", "run_path");
if (run_path == NULL) {
return NULL;
}
PyObject *args = Py_BuildValue("(sOs)", filename, Py_None, modname);
if (args == NULL) {
Py_DECREF(run_path);
return NULL;
}
PyObject *ns = PyObject_Call(run_path, args, NULL);
Py_DECREF(run_path);
Py_DECREF(args);
return ns;
}
static void
set_exc_with_cause(PyObject *exctype, const char *msg)
{
PyObject *cause = PyErr_GetRaisedException();
PyErr_SetString(exctype, msg);
PyObject *exc = PyErr_GetRaisedException();
PyException_SetCause(exc, cause);
PyErr_SetRaisedException(exc);
}
/****************************/
/* module duplication utils */
/****************************/
struct sync_module_result {
PyObject *module;
PyObject *loaded;
PyObject *failed;
};
struct sync_module {
const char *filename;
char _filename[MAXPATHLEN+1];
struct sync_module_result cached;
};
static void
sync_module_clear(struct sync_module *data)
{
data->filename = NULL;
Py_CLEAR(data->cached.module);
Py_CLEAR(data->cached.loaded);
Py_CLEAR(data->cached.failed);
}
static void
sync_module_capture_exc(PyThreadState *tstate, struct sync_module *data)
{
assert(_PyErr_Occurred(tstate));
PyObject *context = data->cached.failed;
PyObject *exc = _PyErr_GetRaisedException(tstate);
_PyErr_SetRaisedException(tstate, Py_NewRef(exc));
if (context != NULL) {
PyException_SetContext(exc, context);
}
data->cached.failed = exc;
}
static int
ensure_isolated_main(PyThreadState *tstate, struct sync_module *main)
{
// Load the module from the original file (or from a cache).
// First try the local cache.
if (main->cached.failed != NULL) {
// We'll deal with this in apply_isolated_main().
assert(main->cached.module == NULL);
assert(main->cached.loaded == NULL);
return 0;
}
else if (main->cached.loaded != NULL) {
assert(main->cached.module != NULL);
return 0;
}
assert(main->cached.module == NULL);
if (main->filename == NULL) {
_PyErr_SetString(tstate, PyExc_NotImplementedError, "");
return -1;
}
// It wasn't in the local cache so we'll need to populate it.
PyObject *mod = _Py_GetMainModule(tstate);
if (_Py_CheckMainModule(mod) < 0) {
// This is probably unrecoverable, so don't bother caching the error.
assert(_PyErr_Occurred(tstate));
Py_XDECREF(mod);
return -1;
}
PyObject *loaded = NULL;
// Try the per-interpreter cache for the loaded module.
// XXX Store it in sys.modules?
PyObject *interpns = PyInterpreterState_GetDict(tstate->interp);
assert(interpns != NULL);
PyObject *key = PyUnicode_FromString("CACHED_MODULE_NS___main__");
if (key == NULL) {
// It's probably unrecoverable, so don't bother caching the error.
Py_DECREF(mod);
return -1;
}
else if (PyDict_GetItemRef(interpns, key, &loaded) < 0) {
// It's probably unrecoverable, so don't bother caching the error.
Py_DECREF(mod);
Py_DECREF(key);
return -1;
}
else if (loaded == NULL) {
// It wasn't already loaded from file.
loaded = PyModule_NewObject(&_Py_ID(__main__));
if (loaded == NULL) {
goto error;
}
PyObject *ns = _PyModule_GetDict(loaded);
// We don't want to trigger "if __name__ == '__main__':",
// so we use a bogus module name.
PyObject *loaded_ns =
runpy_run_path(main->filename, "<fake __main__>");
if (loaded_ns == NULL) {
goto error;
}
int res = PyDict_Update(ns, loaded_ns);
Py_DECREF(loaded_ns);
if (res < 0) {
goto error;
}
// Set the per-interpreter cache entry.
if (PyDict_SetItem(interpns, key, loaded) < 0) {
goto error;
}
}
Py_DECREF(key);
main->cached = (struct sync_module_result){
.module = mod,
.loaded = loaded,
};
return 0;
error:
sync_module_capture_exc(tstate, main);
Py_XDECREF(loaded);
Py_DECREF(mod);
Py_XDECREF(key);
return -1;
}
#ifndef NDEBUG
static int
main_mod_matches(PyObject *expected)
{
PyObject *mod = PyImport_GetModule(&_Py_ID(__main__));
Py_XDECREF(mod);
return mod == expected;
}
#endif
static int
apply_isolated_main(PyThreadState *tstate, struct sync_module *main)
{
assert((main->cached.loaded == NULL) == (main->cached.loaded == NULL));
if (main->cached.failed != NULL) {
// It must have failed previously.
assert(main->cached.loaded == NULL);
_PyErr_SetRaisedException(tstate, main->cached.failed);
return -1;
}
assert(main->cached.loaded != NULL);
assert(main_mod_matches(main->cached.module));
if (_PyImport_SetModule(&_Py_ID(__main__), main->cached.loaded) < 0) {
sync_module_capture_exc(tstate, main);
return -1;
}
return 0;
}
static void
restore_main(PyThreadState *tstate, struct sync_module *main)
{
assert(main->cached.failed == NULL);
assert(main->cached.module != NULL);
assert(main->cached.loaded != NULL);
PyObject *exc = _PyErr_GetRaisedException(tstate);
assert(main_mod_matches(main->cached.loaded));
int res = _PyImport_SetModule(&_Py_ID(__main__), main->cached.module);
assert(res == 0);
if (res < 0) {
PyErr_FormatUnraisable("Exception ignored while restoring __main__");
}
_PyErr_SetRaisedException(tstate, exc);
}
/**************/
/* exceptions */
/**************/
typedef struct xi_exceptions exceptions_t;
static int init_static_exctypes(exceptions_t *, PyInterpreterState *);
static void fini_static_exctypes(exceptions_t *, PyInterpreterState *);
static int init_heap_exctypes(exceptions_t *);
static void fini_heap_exctypes(exceptions_t *);
#include "crossinterp_exceptions.h"
/***************************/
/* cross-interpreter calls */
/***************************/
int
_Py_CallInInterpreter(PyInterpreterState *interp,
_Py_simple_func func, void *arg)
{
if (interp == PyInterpreterState_Get()) {
return func(arg);
}
// XXX Emit a warning if this fails?
_PyEval_AddPendingCall(interp, (_Py_pending_call_func)func, arg, 0);
return 0;
}
int
_Py_CallInInterpreterAndRawFree(PyInterpreterState *interp,
_Py_simple_func func, void *arg)
{
if (interp == PyInterpreterState_Get()) {
int res = func(arg);
PyMem_RawFree(arg);
return res;
}
// XXX Emit a warning if this fails?
_PyEval_AddPendingCall(interp, func, arg, _Py_PENDING_RAWFREE);
return 0;
}
/**************************/
/* cross-interpreter data */
/**************************/
/* registry of {type -> _PyXIData_getdata_t} */
/* For now we use a global registry of shareable classes.
An alternative would be to add a tp_* slot for a class's
_PyXIData_getdata_t. It would be simpler and more efficient. */
static void xid_lookup_init(_PyXIData_lookup_t *);
static void xid_lookup_fini(_PyXIData_lookup_t *);
struct _dlcontext;
static _PyXIData_getdata_t lookup_getdata(struct _dlcontext *, PyObject *);
#include "crossinterp_data_lookup.h"
/* lifecycle */
_PyXIData_t *
_PyXIData_New(void)
{
_PyXIData_t *xid = PyMem_RawCalloc(1, sizeof(_PyXIData_t));
if (xid == NULL) {
PyErr_NoMemory();
}
return xid;
}
void
_PyXIData_Free(_PyXIData_t *xid)
{
PyInterpreterState *interp = PyInterpreterState_Get();
_PyXIData_Clear(interp, xid);
PyMem_RawFree(xid);
}
/* defining cross-interpreter data */
static inline void
_xidata_init(_PyXIData_t *xidata)
{
// If the value is being reused
// then _xidata_clear() should have been called already.
assert(xidata->data == NULL);
assert(xidata->obj == NULL);
*xidata = (_PyXIData_t){0};
_PyXIData_INTERPID(xidata) = -1;
}
static inline void
_xidata_clear(_PyXIData_t *xidata)
{
// _PyXIData_t only has two members that need to be
// cleaned up, if set: "xidata" must be freed and "obj" must be decref'ed.
// In both cases the original (owning) interpreter must be used,
// which is the caller's responsibility to ensure.
if (xidata->data != NULL) {
if (xidata->free != NULL) {
xidata->free(xidata->data);
}
xidata->data = NULL;
}
Py_CLEAR(xidata->obj);
}
void
_PyXIData_Init(_PyXIData_t *xidata,
PyInterpreterState *interp,
void *shared, PyObject *obj,
xid_newobjfunc new_object)
{
assert(xidata != NULL);
assert(new_object != NULL);
_xidata_init(xidata);
xidata->data = shared;
if (obj != NULL) {
assert(interp != NULL);
// released in _PyXIData_Clear()
xidata->obj = Py_NewRef(obj);
}
// Ideally every object would know its owning interpreter.
// Until then, we have to rely on the caller to identify it
// (but we don't need it in all cases).
_PyXIData_INTERPID(xidata) = (interp != NULL)
? PyInterpreterState_GetID(interp)
: -1;
xidata->new_object = new_object;
}
int
_PyXIData_InitWithSize(_PyXIData_t *xidata,
PyInterpreterState *interp,
const size_t size, PyObject *obj,
xid_newobjfunc new_object)
{
assert(size > 0);
// For now we always free the shared data in the same interpreter
// where it was allocated, so the interpreter is required.
assert(interp != NULL);
_PyXIData_Init(xidata, interp, NULL, obj, new_object);
xidata->data = PyMem_RawCalloc(1, size);
if (xidata->data == NULL) {
return -1;
}
xidata->free = PyMem_RawFree;
return 0;
}
void
_PyXIData_Clear(PyInterpreterState *interp, _PyXIData_t *xidata)
{
assert(xidata != NULL);
// This must be called in the owning interpreter.
assert(interp == NULL
|| _PyXIData_INTERPID(xidata) == -1
|| _PyXIData_INTERPID(xidata) == PyInterpreterState_GetID(interp));
_xidata_clear(xidata);
}
/* getting cross-interpreter data */
static inline void
_set_xid_lookup_failure(PyThreadState *tstate, PyObject *obj, const char *msg,
PyObject *cause)
{
if (msg != NULL) {
assert(obj == NULL);
set_notshareableerror(tstate, cause, 0, msg);
}
else if (obj == NULL) {
msg = "object does not support cross-interpreter data";
set_notshareableerror(tstate, cause, 0, msg);
}
else {
msg = "%R does not support cross-interpreter data";
format_notshareableerror(tstate, cause, 0, msg, obj);
}
}
int
_PyObject_CheckXIData(PyThreadState *tstate, PyObject *obj)
{
dlcontext_t ctx;
if (get_lookup_context(tstate, &ctx) < 0) {
return -1;
}
_PyXIData_getdata_t getdata = lookup_getdata(&ctx, obj);
if (getdata.basic == NULL && getdata.fallback == NULL) {
if (!_PyErr_Occurred(tstate)) {
_set_xid_lookup_failure(tstate, obj, NULL, NULL);
}
return -1;
}
return 0;
}
static int
_check_xidata(PyThreadState *tstate, _PyXIData_t *xidata)
{
// xidata->data can be anything, including NULL, so we don't check it.
// xidata->obj may be NULL, so we don't check it.
if (_PyXIData_INTERPID(xidata) < 0) {
PyErr_SetString(PyExc_SystemError, "missing interp");
return -1;
}
if (xidata->new_object == NULL) {
PyErr_SetString(PyExc_SystemError, "missing new_object func");
return -1;
}
// xidata->free may be NULL, so we don't check it.
return 0;
}
static int
_get_xidata(PyThreadState *tstate,
PyObject *obj, xidata_fallback_t fallback, _PyXIData_t *xidata)
{
PyInterpreterState *interp = tstate->interp;
assert(xidata->data == NULL);
assert(xidata->obj == NULL);
if (xidata->data != NULL || xidata->obj != NULL) {
_PyErr_SetString(tstate, PyExc_ValueError, "xidata not cleared");
return -1;
}
// Call the "getdata" func for the object.
dlcontext_t ctx;
if (get_lookup_context(tstate, &ctx) < 0) {
return -1;
}
Py_INCREF(obj);
_PyXIData_getdata_t getdata = lookup_getdata(&ctx, obj);
if (getdata.basic == NULL && getdata.fallback == NULL) {
if (PyErr_Occurred()) {
Py_DECREF(obj);
return -1;
}
// Fall back to obj
Py_DECREF(obj);
if (!_PyErr_Occurred(tstate)) {
_set_xid_lookup_failure(tstate, obj, NULL, NULL);
}
return -1;
}
int res = getdata.basic != NULL
? getdata.basic(tstate, obj, xidata)
: getdata.fallback(tstate, obj, fallback, xidata);
Py_DECREF(obj);
if (res != 0) {
PyObject *cause = _PyErr_GetRaisedException(tstate);
assert(cause != NULL);
_set_xid_lookup_failure(tstate, obj, NULL, cause);
Py_XDECREF(cause);
return -1;
}
// Fill in the blanks and validate the result.
_PyXIData_INTERPID(xidata) = PyInterpreterState_GetID(interp);
if (_check_xidata(tstate, xidata) != 0) {
(void)_PyXIData_Release(xidata);
return -1;
}
return 0;
}
int
_PyObject_GetXIDataNoFallback(PyThreadState *tstate,
PyObject *obj, _PyXIData_t *xidata)
{
return _get_xidata(tstate, obj, _PyXIDATA_XIDATA_ONLY, xidata);
}
int
_PyObject_GetXIData(PyThreadState *tstate,
PyObject *obj, xidata_fallback_t fallback,
_PyXIData_t *xidata)
{
switch (fallback) {
case _PyXIDATA_XIDATA_ONLY:
return _get_xidata(tstate, obj, fallback, xidata);
case _PyXIDATA_FULL_FALLBACK:
if (_get_xidata(tstate, obj, fallback, xidata) == 0) {
return 0;
}
PyObject *exc = _PyErr_GetRaisedException(tstate);
if (PyFunction_Check(obj)) {
if (_PyFunction_GetXIData(tstate, obj, xidata) == 0) {
Py_DECREF(exc);
return 0;
}
_PyErr_Clear(tstate);
}
// We could try _PyMarshal_GetXIData() but we won't for now.
if (_PyPickle_GetXIData(tstate, obj, xidata) == 0) {
Py_DECREF(exc);
return 0;
}
// Raise the original exception.
_PyErr_SetRaisedException(tstate, exc);
return -1;
default:
#ifdef Py_DEBUG
Py_FatalError("unsupported xidata fallback option");
#endif
_PyErr_SetString(tstate, PyExc_SystemError,
"unsupported xidata fallback option");
return -1;
}
}
/* pickle C-API */
struct _pickle_context {
PyThreadState *tstate;
};
static PyObject *
_PyPickle_Dumps(struct _pickle_context *ctx, PyObject *obj)
{
PyObject *dumps = PyImport_ImportModuleAttrString("pickle", "dumps");
if (dumps == NULL) {
return NULL;
}
PyObject *bytes = PyObject_CallOneArg(dumps, obj);
Py_DECREF(dumps);
return bytes;
}
struct _unpickle_context {
PyThreadState *tstate;
// We only special-case the __main__ module,
// since other modules behave consistently.
struct sync_module main;
};
static void
_unpickle_context_clear(struct _unpickle_context *ctx)
{
sync_module_clear(&ctx->main);
}
static int
check_missing___main___attr(PyObject *exc)
{
assert(!PyErr_Occurred());
if (!PyErr_GivenExceptionMatches(exc, PyExc_AttributeError)) {
return 0;
}
// Get the error message.
PyObject *args = PyException_GetArgs(exc);
if (args == NULL || args == Py_None || PyObject_Size(args) < 1) {
assert(!PyErr_Occurred());
return 0;
}
PyObject *msgobj = args;
if (!PyUnicode_Check(msgobj)) {
msgobj = PySequence_GetItem(args, 0);
Py_DECREF(args);
if (msgobj == NULL) {
PyErr_Clear();
return 0;
}
}
const char *err = PyUnicode_AsUTF8(msgobj);
// Check if it's a missing __main__ attr.
int cmp = strncmp(err, "module '__main__' has no attribute '", 36);
Py_DECREF(msgobj);
return cmp == 0;
}
static PyObject *
_PyPickle_Loads(struct _unpickle_context *ctx, PyObject *pickled)
{
PyThreadState *tstate = ctx->tstate;
PyObject *exc = NULL;
PyObject *loads = PyImport_ImportModuleAttrString("pickle", "loads");
if (loads == NULL) {
return NULL;
}
// Make an initial attempt to unpickle.
PyObject *obj = PyObject_CallOneArg(loads, pickled);
if (obj != NULL) {
goto finally;
}
assert(_PyErr_Occurred(tstate));
if (ctx == NULL) {
goto finally;
}
exc = _PyErr_GetRaisedException(tstate);
if (!check_missing___main___attr(exc)) {
goto finally;
}
// Temporarily swap in a fake __main__ loaded from the original
// file and cached. Note that functions will use the cached ns
// for __globals__, // not the actual module.
if (ensure_isolated_main(tstate, &ctx->main) < 0) {
goto finally;
}
if (apply_isolated_main(tstate, &ctx->main) < 0) {
goto finally;
}
// Try to unpickle once more.
obj = PyObject_CallOneArg(loads, pickled);
restore_main(tstate, &ctx->main);
if (obj == NULL) {
goto finally;
}
Py_CLEAR(exc);
finally:
if (exc != NULL) {
if (_PyErr_Occurred(tstate)) {
sync_module_capture_exc(tstate, &ctx->main);
}
// We restore the original exception.
// It might make sense to chain it (__context__).
_PyErr_SetRaisedException(tstate, exc);
}
Py_DECREF(loads);
return obj;
}
/* pickle wrapper */
struct _pickle_xid_context {
// __main__.__file__
struct {
const char *utf8;
size_t len;
char _utf8[MAXPATHLEN+1];
} mainfile;
};
static int
_set_pickle_xid_context(PyThreadState *tstate, struct _pickle_xid_context *ctx)
{
// Set mainfile if possible.
Py_ssize_t len = _Py_GetMainfile(ctx->mainfile._utf8, MAXPATHLEN);
if (len < 0) {
// For now we ignore any exceptions.
PyErr_Clear();
}
else if (len > 0) {
ctx->mainfile.utf8 = ctx->mainfile._utf8;
ctx->mainfile.len = (size_t)len;
}
return 0;
}
struct _shared_pickle_data {
_PyBytes_data_t pickled; // Must be first if we use _PyBytes_FromXIData().
struct _pickle_xid_context ctx;
};
PyObject *
_PyPickle_LoadFromXIData(_PyXIData_t *xidata)
{
PyThreadState *tstate = _PyThreadState_GET();
struct _shared_pickle_data *shared =
(struct _shared_pickle_data *)xidata->data;
// We avoid copying the pickled data by wrapping it in a memoryview.
// The alternative is to get a bytes object using _PyBytes_FromXIData().
PyObject *pickled = PyMemoryView_FromMemory(
(char *)shared->pickled.bytes, shared->pickled.len, PyBUF_READ);
if (pickled == NULL) {
return NULL;
}
// Unpickle the object.
struct _unpickle_context ctx = {
.tstate = tstate,
.main = {
.filename = shared->ctx.mainfile.utf8,
},
};
PyObject *obj = _PyPickle_Loads(&ctx, pickled);
Py_DECREF(pickled);
_unpickle_context_clear(&ctx);
if (obj == NULL) {
PyObject *cause = _PyErr_GetRaisedException(tstate);
assert(cause != NULL);
_set_xid_lookup_failure(
tstate, NULL, "object could not be unpickled", cause);
Py_DECREF(cause);
}
return obj;
}
int
_PyPickle_GetXIData(PyThreadState *tstate, PyObject *obj, _PyXIData_t *xidata)
{
// Pickle the object.
struct _pickle_context ctx = {
.tstate = tstate,
};
PyObject *bytes = _PyPickle_Dumps(&ctx, obj);
if (bytes == NULL) {
PyObject *cause = _PyErr_GetRaisedException(tstate);
assert(cause != NULL);
_set_xid_lookup_failure(
tstate, NULL, "object could not be pickled", cause);
Py_DECREF(cause);
return -1;
}
// If we had an "unwrapper" mechnanism, we could call
// _PyObject_GetXIData() on the bytes object directly and add
// a simple unwrapper to call pickle.loads() on the bytes.
size_t size = sizeof(struct _shared_pickle_data);
struct _shared_pickle_data *shared =
(struct _shared_pickle_data *)_PyBytes_GetXIDataWrapped(
tstate, bytes, size, _PyPickle_LoadFromXIData, xidata);
Py_DECREF(bytes);
if (shared == NULL) {
return -1;
}
// If it mattered, we could skip getting __main__.__file__
// when "__main__" doesn't show up in the pickle bytes.
if (_set_pickle_xid_context(tstate, &shared->ctx) < 0) {
_xidata_clear(xidata);
return -1;
}
return 0;
}
/* marshal wrapper */
PyObject *
_PyMarshal_ReadObjectFromXIData(_PyXIData_t *xidata)
{
PyThreadState *tstate = _PyThreadState_GET();
_PyBytes_data_t *shared = (_PyBytes_data_t *)xidata->data;
PyObject *obj = PyMarshal_ReadObjectFromString(shared->bytes, shared->len);
if (obj == NULL) {
PyObject *cause = _PyErr_GetRaisedException(tstate);
assert(cause != NULL);
_set_xid_lookup_failure(
tstate, NULL, "object could not be unmarshalled", cause);
Py_DECREF(cause);
return NULL;
}
return obj;
}
int
_PyMarshal_GetXIData(PyThreadState *tstate, PyObject *obj, _PyXIData_t *xidata)
{
PyObject *bytes = PyMarshal_WriteObjectToString(obj, Py_MARSHAL_VERSION);
if (bytes == NULL) {
PyObject *cause = _PyErr_GetRaisedException(tstate);
assert(cause != NULL);
_set_xid_lookup_failure(
tstate, NULL, "object could not be marshalled", cause);
Py_DECREF(cause);
return -1;
}
size_t size = sizeof(_PyBytes_data_t);
_PyBytes_data_t *shared = _PyBytes_GetXIDataWrapped(
tstate, bytes, size, _PyMarshal_ReadObjectFromXIData, xidata);
Py_DECREF(bytes);
if (shared == NULL) {
return -1;
}
return 0;
}
/* script wrapper */
static int
verify_script(PyThreadState *tstate, PyCodeObject *co, int checked, int pure)
{
// Make sure it isn't a closure and (optionally) doesn't use globals.
PyObject *builtins = NULL;
if (pure) {
builtins = _PyEval_GetBuiltins(tstate);
assert(builtins != NULL);
}
if (checked) {
assert(_PyCode_VerifyStateless(tstate, co, NULL, NULL, builtins) == 0);
}
else if (_PyCode_VerifyStateless(tstate, co, NULL, NULL, builtins) < 0) {
return -1;
}
// Make sure it doesn't have args.
if (co->co_argcount > 0
|| co->co_posonlyargcount > 0
|| co->co_kwonlyargcount > 0
|| co->co_flags & (CO_VARARGS | CO_VARKEYWORDS))
{
_PyErr_SetString(tstate, PyExc_ValueError,
"code with args not supported");
return -1;
}
// Make sure it doesn't return anything.
if (!_PyCode_ReturnsOnlyNone(co)) {
_PyErr_SetString(tstate, PyExc_ValueError,
"code that returns a value is not a script");
return -1;
}
return 0;
}
static int
get_script_xidata(PyThreadState *tstate, PyObject *obj, int pure,
_PyXIData_t *xidata)
{
// Get the corresponding code object.
PyObject *code = NULL;
int checked = 0;
if (PyCode_Check(obj)) {
code = obj;
Py_INCREF(code);
}
else if (PyFunction_Check(obj)) {
code = PyFunction_GET_CODE(obj);
assert(code != NULL);
Py_INCREF(code);
if (pure) {
if (_PyFunction_VerifyStateless(tstate, obj) < 0) {
goto error;
}
checked = 1;
}
}
else {
const char *filename = "<script>";
int optimize = 0;
PyCompilerFlags cf = _PyCompilerFlags_INIT;
cf.cf_flags = PyCF_SOURCE_IS_UTF8;
PyObject *ref = NULL;
const char *script = _Py_SourceAsString(obj, "???", "???", &cf, &ref);
if (script == NULL) {
if (!_PyObject_SupportedAsScript(obj)) {
// We discard the raised exception.
_PyErr_Format(tstate, PyExc_TypeError,
"unsupported script %R", obj);
}
goto error;
}
#ifdef Py_GIL_DISABLED
// Don't immortalize code constants to avoid memory leaks.
((_PyThreadStateImpl *)tstate)->suppress_co_const_immortalization++;
#endif
code = Py_CompileStringExFlags(
script, filename, Py_file_input, &cf, optimize);
#ifdef Py_GIL_DISABLED
((_PyThreadStateImpl *)tstate)->suppress_co_const_immortalization--;
#endif
Py_XDECREF(ref);
if (code == NULL) {
goto error;
}
// Compiled text can't have args or any return statements,
// nor be a closure. It can use globals though.
if (!pure) {
// We don't need to check for globals either.
checked = 1;
}
}
// Make sure it's actually a script.
if (verify_script(tstate, (PyCodeObject *)code, checked, pure) < 0) {
goto error;
}
// Convert the code object.
int res = _PyCode_GetXIData(tstate, code, xidata);
Py_DECREF(code);
if (res < 0) {
return -1;
}
return 0;
error:
Py_XDECREF(code);
PyObject *cause = _PyErr_GetRaisedException(tstate);
assert(cause != NULL);
_set_xid_lookup_failure(
tstate, NULL, "object not a valid script", cause);
Py_DECREF(cause);
return -1;
}
int
_PyCode_GetScriptXIData(PyThreadState *tstate,
PyObject *obj, _PyXIData_t *xidata)
{
return get_script_xidata(tstate, obj, 0, xidata);
}
int
_PyCode_GetPureScriptXIData(PyThreadState *tstate,
PyObject *obj, _PyXIData_t *xidata)
{
return get_script_xidata(tstate, obj, 1, xidata);
}
/* using cross-interpreter data */
PyObject *
_PyXIData_NewObject(_PyXIData_t *xidata)
{
return xidata->new_object(xidata);
}
static int
_call_clear_xidata(void *data)
{
_xidata_clear((_PyXIData_t *)data);
return 0;
}
static int
_xidata_release(_PyXIData_t *xidata, int rawfree)
{
if ((xidata->data == NULL || xidata->free == NULL) && xidata->obj == NULL) {
// Nothing to release!
if (rawfree) {
PyMem_RawFree(xidata);
}
else {
xidata->data = NULL;
}
return 0;
}
// Switch to the original interpreter.
PyInterpreterState *interp = _PyInterpreterState_LookUpID(
_PyXIData_INTERPID(xidata));
if (interp == NULL) {
// The interpreter was already destroyed.
// This function shouldn't have been called.
// XXX Someone leaked some memory...
assert(PyErr_Occurred());
if (rawfree) {
PyMem_RawFree(xidata);
}
return -1;
}
// "Release" the data and/or the object.
if (rawfree) {
return _Py_CallInInterpreterAndRawFree(interp, _call_clear_xidata, xidata);
}
else {
return _Py_CallInInterpreter(interp, _call_clear_xidata, xidata);
}
}
int
_PyXIData_Release(_PyXIData_t *xidata)
{
return _xidata_release(xidata, 0);
}
int
_PyXIData_ReleaseAndRawFree(_PyXIData_t *xidata)
{
return _xidata_release(xidata, 1);
}
/*************************/
/* convenience utilities */
/*************************/
static const char *
_copy_string_obj_raw(PyObject *strobj, Py_ssize_t *p_size)
{
Py_ssize_t size = -1;
const char *str = PyUnicode_AsUTF8AndSize(strobj, &size);
if (str == NULL) {
return NULL;
}
if (size != (Py_ssize_t)strlen(str)) {
PyErr_SetString(PyExc_ValueError, "found embedded NULL character");
return NULL;
}
char *copied = PyMem_RawMalloc(size+1);
if (copied == NULL) {
PyErr_NoMemory();
return NULL;
}
strcpy(copied, str);
if (p_size != NULL) {
*p_size = size;
}
return copied;
}
static int
_convert_exc_to_TracebackException(PyObject *exc, PyObject **p_tbexc)
{
PyObject *args = NULL;
PyObject *kwargs = NULL;
PyObject *create = NULL;
// This is inspired by _PyErr_Display().
PyObject *tbexc_type = PyImport_ImportModuleAttrString(
"traceback",
"TracebackException");
if (tbexc_type == NULL) {
return -1;
}
create = PyObject_GetAttrString(tbexc_type, "from_exception");
Py_DECREF(tbexc_type);
if (create == NULL) {
return -1;
}
args = PyTuple_Pack(1, exc);
if (args == NULL) {
goto error;
}
kwargs = PyDict_New();
if (kwargs == NULL) {
goto error;
}
if (PyDict_SetItemString(kwargs, "save_exc_type", Py_False) < 0) {
goto error;
}
if (PyDict_SetItemString(kwargs, "lookup_lines", Py_False) < 0) {
goto error;
}
PyObject *tbexc = PyObject_Call(create, args, kwargs);
Py_DECREF(args);
Py_DECREF(kwargs);
Py_DECREF(create);
if (tbexc == NULL) {
goto error;
}
*p_tbexc = tbexc;
return 0;
error:
Py_XDECREF(args);
Py_XDECREF(kwargs);
Py_XDECREF(create);
return -1;
}
// We accommodate backports here.
#ifndef _Py_EMPTY_STR
# define _Py_EMPTY_STR &_Py_STR(empty)
#endif
static const char *
_format_TracebackException(PyObject *tbexc)
{
PyObject *lines = PyObject_CallMethod(tbexc, "format", NULL);
if (lines == NULL) {
return NULL;
}
assert(_Py_EMPTY_STR != NULL);
PyObject *formatted_obj = PyUnicode_Join(_Py_EMPTY_STR, lines);
Py_DECREF(lines);
if (formatted_obj == NULL) {
return NULL;
}
Py_ssize_t size = -1;
const char *formatted = _copy_string_obj_raw(formatted_obj, &size);
Py_DECREF(formatted_obj);
// We remove trailing the newline added by TracebackException.format().
assert(formatted[size-1] == '\n');
((char *)formatted)[size-1] = '\0';
return formatted;
}
static int
_release_xid_data(_PyXIData_t *xidata, int rawfree)
{
PyObject *exc = PyErr_GetRaisedException();
int res = rawfree
? _PyXIData_ReleaseAndRawFree(xidata)
: _PyXIData_Release(xidata);
if (res < 0) {
/* The owning interpreter is already destroyed. */
_PyXIData_Clear(NULL, xidata);
// XXX Emit a warning?
PyErr_Clear();
}
PyErr_SetRaisedException(exc);
return res;
}
/***********************/
/* exception snapshots */
/***********************/
static int
_excinfo_init_type_from_exception(struct _excinfo_type *info, PyObject *exc)
{
/* Note that this copies directly rather than into an intermediate
struct and does not clear on error. If we need that then we
should have a separate function to wrap this one
and do all that there. */
PyObject *strobj = NULL;
PyTypeObject *type = Py_TYPE(exc);
if (type->tp_flags & _Py_TPFLAGS_STATIC_BUILTIN) {
assert(_Py_IsImmortal((PyObject *)type));
info->builtin = type;
}
else {
// Only builtin types are preserved.
info->builtin = NULL;
}
// __name__
strobj = PyType_GetName(type);
if (strobj == NULL) {
return -1;
}
info->name = _copy_string_obj_raw(strobj, NULL);
Py_DECREF(strobj);
if (info->name == NULL) {
return -1;
}
// __qualname__
strobj = PyType_GetQualName(type);
if (strobj == NULL) {
return -1;
}
info->qualname = _copy_string_obj_raw(strobj, NULL);
Py_DECREF(strobj);
if (info->qualname == NULL) {
return -1;
}
// __module__
strobj = PyType_GetModuleName(type);
if (strobj == NULL) {
return -1;
}
info->module = _copy_string_obj_raw(strobj, NULL);
Py_DECREF(strobj);
if (info->module == NULL) {
return -1;
}
return 0;
}
static int
_excinfo_init_type_from_object(struct _excinfo_type *info, PyObject *exctype)
{
PyObject *strobj = NULL;
// __name__
strobj = PyObject_GetAttrString(exctype, "__name__");
if (strobj == NULL) {
return -1;
}
info->name = _copy_string_obj_raw(strobj, NULL);
Py_DECREF(strobj);
if (info->name == NULL) {
return -1;
}
// __qualname__
strobj = PyObject_GetAttrString(exctype, "__qualname__");
if (strobj == NULL) {
return -1;
}
info->qualname = _copy_string_obj_raw(strobj, NULL);
Py_DECREF(strobj);
if (info->qualname == NULL) {
return -1;
}
// __module__
strobj = PyObject_GetAttrString(exctype, "__module__");
if (strobj == NULL) {
return -1;
}
info->module = _copy_string_obj_raw(strobj, NULL);
Py_DECREF(strobj);
if (info->module == NULL) {
return -1;
}
return 0;
}
static void
_excinfo_clear_type(struct _excinfo_type *info)
{
if (info->builtin != NULL) {
assert(info->builtin->tp_flags & _Py_TPFLAGS_STATIC_BUILTIN);
assert(_Py_IsImmortal((PyObject *)info->builtin));
}
if (info->name != NULL) {
PyMem_RawFree((void *)info->name);
}
if (info->qualname != NULL) {
PyMem_RawFree((void *)info->qualname);
}
if (info->module != NULL) {
PyMem_RawFree((void *)info->module);
}
*info = (struct _excinfo_type){NULL};
}
static void
_excinfo_normalize_type(struct _excinfo_type *info,
const char **p_module, const char **p_qualname)
{
if (info->name == NULL) {
assert(info->builtin == NULL);
assert(info->qualname == NULL);
assert(info->module == NULL);
// This is inspired by TracebackException.format_exception_only().
*p_module = NULL;
*p_qualname = NULL;
return;
}
const char *module = info->module;
const char *qualname = info->qualname;
if (qualname == NULL) {
qualname = info->name;
}
assert(module != NULL);
if (strcmp(module, "builtins") == 0) {
module = NULL;
}
else if (strcmp(module, "__main__") == 0) {
module = NULL;
}
*p_qualname = qualname;
*p_module = module;
}
static int
excinfo_is_set(_PyXI_excinfo *info)
{
return info->type.name != NULL || info->msg != NULL;
}
static void
_PyXI_excinfo_clear(_PyXI_excinfo *info)
{
_excinfo_clear_type(&info->type);
if (info->msg != NULL) {
PyMem_RawFree((void *)info->msg);
}
if (info->errdisplay != NULL) {
PyMem_RawFree((void *)info->errdisplay);
}
*info = (_PyXI_excinfo){{NULL}};
}
PyObject *
_PyXI_excinfo_format(_PyXI_excinfo *info)
{
const char *module, *qualname;
_excinfo_normalize_type(&info->type, &module, &qualname);
if (qualname != NULL) {
if (module != NULL) {
if (info->msg != NULL) {
return PyUnicode_FromFormat("%s.%s: %s",
module, qualname, info->msg);
}
else {
return PyUnicode_FromFormat("%s.%s", module, qualname);
}
}
else {
if (info->msg != NULL) {
return PyUnicode_FromFormat("%s: %s", qualname, info->msg);
}
else {
return PyUnicode_FromString(qualname);
}
}
}
else if (info->msg != NULL) {
return PyUnicode_FromString(info->msg);
}
else {
Py_RETURN_NONE;
}
}
static const char *
_PyXI_excinfo_InitFromException(_PyXI_excinfo *info, PyObject *exc)
{
assert(exc != NULL);
if (PyErr_GivenExceptionMatches(exc, PyExc_MemoryError)) {
_PyXI_excinfo_clear(info);
return NULL;
}
const char *failure = NULL;
if (_excinfo_init_type_from_exception(&info->type, exc) < 0) {
failure = "error while initializing exception type snapshot";
goto error;
}
// Extract the exception message.
PyObject *msgobj = PyObject_Str(exc);
if (msgobj == NULL) {
failure = "error while formatting exception";
goto error;
}
info->msg = _copy_string_obj_raw(msgobj, NULL);
Py_DECREF(msgobj);
if (info->msg == NULL) {
failure = "error while copying exception message";
goto error;
}
// Pickle a traceback.TracebackException.
PyObject *tbexc = NULL;
if (_convert_exc_to_TracebackException(exc, &tbexc) < 0) {
#ifdef Py_DEBUG
PyErr_FormatUnraisable("Exception ignored while creating TracebackException");
#endif
PyErr_Clear();
}
else {
info->errdisplay = _format_TracebackException(tbexc);
Py_DECREF(tbexc);
if (info->errdisplay == NULL) {
#ifdef Py_DEBUG
PyErr_FormatUnraisable("Exception ignored while formatting TracebackException");
#endif
PyErr_Clear();
}
}
return NULL;
error:
assert(failure != NULL);
_PyXI_excinfo_clear(info);
return failure;
}
static const char *
_PyXI_excinfo_InitFromObject(_PyXI_excinfo *info, PyObject *obj)
{
const char *failure = NULL;
PyObject *exctype = PyObject_GetAttrString(obj, "type");
if (exctype == NULL) {
failure = "exception snapshot missing 'type' attribute";
goto error;
}
int res = _excinfo_init_type_from_object(&info->type, exctype);
Py_DECREF(exctype);
if (res < 0) {
failure = "error while initializing exception type snapshot";
goto error;
}
// Extract the exception message.
PyObject *msgobj = PyObject_GetAttrString(obj, "msg");
if (msgobj == NULL) {
failure = "exception snapshot missing 'msg' attribute";
goto error;
}
info->msg = _copy_string_obj_raw(msgobj, NULL);
Py_DECREF(msgobj);
if (info->msg == NULL) {
failure = "error while copying exception message";
goto error;
}
// Pickle a traceback.TracebackException.
PyObject *errdisplay = PyObject_GetAttrString(obj, "errdisplay");
if (errdisplay == NULL) {
failure = "exception snapshot missing 'errdisplay' attribute";
goto error;
}
info->errdisplay = _copy_string_obj_raw(errdisplay, NULL);
Py_DECREF(errdisplay);
if (info->errdisplay == NULL) {
failure = "error while copying exception error display";
goto error;
}
return NULL;
error:
assert(failure != NULL);
_PyXI_excinfo_clear(info);
return failure;
}
static void
_PyXI_excinfo_Apply(_PyXI_excinfo *info, PyObject *exctype)
{
PyObject *tbexc = NULL;
if (info->errdisplay != NULL) {
tbexc = PyUnicode_FromString(info->errdisplay);
if (tbexc == NULL) {
PyErr_Clear();
}
else {
PyErr_SetObject(exctype, tbexc);
Py_DECREF(tbexc);
return;
}
}
PyObject *formatted = _PyXI_excinfo_format(info);
PyErr_SetObject(exctype, formatted);
Py_DECREF(formatted);
if (tbexc != NULL) {
PyObject *exc = PyErr_GetRaisedException();
if (PyObject_SetAttrString(exc, "_errdisplay", tbexc) < 0) {
#ifdef Py_DEBUG
PyErr_FormatUnraisable("Exception ignored while "
"setting _errdisplay");
#endif
PyErr_Clear();
}
Py_DECREF(tbexc);
PyErr_SetRaisedException(exc);
}
}
static PyObject *
_PyXI_excinfo_TypeAsObject(_PyXI_excinfo *info)
{
PyObject *ns = _PyNamespace_New(NULL);
if (ns == NULL) {
return NULL;
}
int empty = 1;
if (info->type.name != NULL) {
PyObject *name = PyUnicode_FromString(info->type.name);
if (name == NULL) {
goto error;
}
int res = PyObject_SetAttrString(ns, "__name__", name);
Py_DECREF(name);
if (res < 0) {
goto error;
}
empty = 0;
}
if (info->type.qualname != NULL) {
PyObject *qualname = PyUnicode_FromString(info->type.qualname);
if (qualname == NULL) {
goto error;
}
int res = PyObject_SetAttrString(ns, "__qualname__", qualname);
Py_DECREF(qualname);
if (res < 0) {
goto error;
}
empty = 0;
}
if (info->type.module != NULL) {
PyObject *module = PyUnicode_FromString(info->type.module);
if (module == NULL) {
goto error;
}
int res = PyObject_SetAttrString(ns, "__module__", module);
Py_DECREF(module);
if (res < 0) {
goto error;
}
empty = 0;
}
if (empty) {
Py_CLEAR(ns);
}
return ns;
error:
Py_DECREF(ns);
return NULL;
}
static PyObject *
_PyXI_excinfo_AsObject(_PyXI_excinfo *info)
{
PyObject *ns = _PyNamespace_New(NULL);
if (ns == NULL) {
return NULL;
}
int res;
PyObject *type = _PyXI_excinfo_TypeAsObject(info);
if (type == NULL) {
if (PyErr_Occurred()) {
goto error;
}
type = Py_NewRef(Py_None);
}
res = PyObject_SetAttrString(ns, "type", type);
Py_DECREF(type);
if (res < 0) {
goto error;
}
PyObject *msg = info->msg != NULL
? PyUnicode_FromString(info->msg)
: Py_NewRef(Py_None);
if (msg == NULL) {
goto error;
}
res = PyObject_SetAttrString(ns, "msg", msg);
Py_DECREF(msg);
if (res < 0) {
goto error;
}
PyObject *formatted = _PyXI_excinfo_format(info);
if (formatted == NULL) {
goto error;
}
res = PyObject_SetAttrString(ns, "formatted", formatted);
Py_DECREF(formatted);
if (res < 0) {
goto error;
}
if (info->errdisplay != NULL) {
PyObject *tbexc = PyUnicode_FromString(info->errdisplay);
if (tbexc == NULL) {
PyErr_Clear();
}
else {
res = PyObject_SetAttrString(ns, "errdisplay", tbexc);
Py_DECREF(tbexc);
if (res < 0) {
goto error;
}
}
}
return ns;
error:
Py_DECREF(ns);
return NULL;
}
_PyXI_excinfo *
_PyXI_NewExcInfo(PyObject *exc)
{
assert(!PyErr_Occurred());
if (exc == NULL || exc == Py_None) {
PyErr_SetString(PyExc_ValueError, "missing exc");
return NULL;
}
_PyXI_excinfo *info = PyMem_RawCalloc(1, sizeof(_PyXI_excinfo));
if (info == NULL) {
return NULL;
}
const char *failure;
if (PyExceptionInstance_Check(exc) || PyExceptionClass_Check(exc)) {
failure = _PyXI_excinfo_InitFromException(info, exc);
}
else {
failure = _PyXI_excinfo_InitFromObject(info, exc);
}
if (failure != NULL) {
PyMem_RawFree(info);
set_exc_with_cause(PyExc_Exception, failure);
return NULL;
}
return info;
}
void
_PyXI_FreeExcInfo(_PyXI_excinfo *info)
{
_PyXI_excinfo_clear(info);
PyMem_RawFree(info);
}
PyObject *
_PyXI_FormatExcInfo(_PyXI_excinfo *info)
{
return _PyXI_excinfo_format(info);
}
PyObject *
_PyXI_ExcInfoAsObject(_PyXI_excinfo *info)
{
return _PyXI_excinfo_AsObject(info);
}
/***************************/
/* short-term data sharing */
/***************************/
/* error codes */
static int
_PyXI_ApplyErrorCode(_PyXI_errcode code, PyInterpreterState *interp)
{
PyThreadState *tstate = _PyThreadState_GET();
assert(!PyErr_Occurred());
assert(code != _PyXI_ERR_NO_ERROR);
assert(code != _PyXI_ERR_UNCAUGHT_EXCEPTION);
switch (code) {
case _PyXI_ERR_OTHER:
// XXX msg?
PyErr_SetNone(PyExc_InterpreterError);
break;
case _PyXI_ERR_NO_MEMORY:
PyErr_NoMemory();
break;
case _PyXI_ERR_ALREADY_RUNNING:
assert(interp != NULL);
_PyErr_SetInterpreterAlreadyRunning();
break;
case _PyXI_ERR_MAIN_NS_FAILURE:
PyErr_SetString(PyExc_InterpreterError,
"failed to get __main__ namespace");
break;
case _PyXI_ERR_APPLY_NS_FAILURE:
PyErr_SetString(PyExc_InterpreterError,
"failed to apply namespace to __main__");
break;
case _PyXI_ERR_PRESERVE_FAILURE:
PyErr_SetString(PyExc_InterpreterError,
"failed to preserve objects across session");
break;
case _PyXI_ERR_EXC_PROPAGATION_FAILURE:
PyErr_SetString(PyExc_InterpreterError,
"failed to transfer exception between interpreters");
break;
case _PyXI_ERR_NOT_SHAREABLE:
_set_xid_lookup_failure(tstate, NULL, NULL, NULL);
break;
default:
#ifdef Py_DEBUG
Py_FatalError("unsupported error code");
#else
PyErr_Format(PyExc_RuntimeError, "unsupported error code %d", code);
#endif
}
assert(PyErr_Occurred());
return -1;
}
/* basic failure info */
struct xi_failure {
// The kind of error to propagate.
_PyXI_errcode code;
// The propagated message.
const char *msg;
int msg_owned;
}; // _PyXI_failure
#define XI_FAILURE_INIT (_PyXI_failure){ .code = _PyXI_ERR_NO_ERROR }
static void
clear_xi_failure(_PyXI_failure *failure)
{
if (failure->msg != NULL && failure->msg_owned) {
PyMem_RawFree((void*)failure->msg);
}
*failure = XI_FAILURE_INIT;
}
static void
copy_xi_failure(_PyXI_failure *dest, _PyXI_failure *src)
{
*dest = *src;
dest->msg_owned = 0;
}
_PyXI_failure *
_PyXI_NewFailure(void)
{
_PyXI_failure *failure = PyMem_RawMalloc(sizeof(_PyXI_failure));
if (failure == NULL) {
PyErr_NoMemory();
return NULL;
}
*failure = XI_FAILURE_INIT;
return failure;
}
void
_PyXI_FreeFailure(_PyXI_failure *failure)
{
clear_xi_failure(failure);
PyMem_RawFree(failure);
}
_PyXI_errcode
_PyXI_GetFailureCode(_PyXI_failure *failure)
{
if (failure == NULL) {
return _PyXI_ERR_NO_ERROR;
}
return failure->code;
}
void
_PyXI_InitFailureUTF8(_PyXI_failure *failure,
_PyXI_errcode code, const char *msg)
{
*failure = (_PyXI_failure){
.code = code,
.msg = msg,
.msg_owned = 0,
};
}
int
_PyXI_InitFailure(_PyXI_failure *failure, _PyXI_errcode code, PyObject *obj)
{
*failure = (_PyXI_failure){
.code = code,
.msg = NULL,
.msg_owned = 0,
};
if (obj == NULL) {
return 0;
}
PyObject *msgobj = PyObject_Str(obj);
if (msgobj == NULL) {
return -1;
}
// This will leak if not paired with clear_xi_failure().
// That happens automatically in _capture_current_exception().
const char *msg = _copy_string_obj_raw(msgobj, NULL);
Py_DECREF(msgobj);
if (msg == NULL) {
return -1;
}
*failure = (_PyXI_failure){
.code = code,
.msg = msg,
.msg_owned = 1,
};
return 0;
}
/* shared exceptions */
typedef struct {
// The originating interpreter.
PyInterpreterState *interp;
// The error to propagate, if different from the uncaught exception.
_PyXI_failure *override;
_PyXI_failure _override;
// The exception information to propagate, if applicable.
// This is populated only for some error codes,
// but always for _PyXI_ERR_UNCAUGHT_EXCEPTION.
_PyXI_excinfo uncaught;
} _PyXI_error;
static void
xi_error_clear(_PyXI_error *err)
{
err->interp = NULL;
if (err->override != NULL) {
clear_xi_failure(err->override);
}
_PyXI_excinfo_clear(&err->uncaught);
}
static int
xi_error_is_set(_PyXI_error *error)
{
if (error->override != NULL) {
assert(error->override->code != _PyXI_ERR_NO_ERROR);
assert(error->override->code != _PyXI_ERR_UNCAUGHT_EXCEPTION
|| excinfo_is_set(&error->uncaught));
return 1;
}
return excinfo_is_set(&error->uncaught);
}
static int
xi_error_has_override(_PyXI_error *err)
{
if (err->override == NULL) {
return 0;
}
return (err->override->code != _PyXI_ERR_NO_ERROR
&& err->override->code != _PyXI_ERR_UNCAUGHT_EXCEPTION);
}
static PyObject *
xi_error_resolve_current_exc(PyThreadState *tstate,
_PyXI_failure *override)
{
assert(override == NULL || override->code != _PyXI_ERR_NO_ERROR);
PyObject *exc = _PyErr_GetRaisedException(tstate);
if (exc == NULL) {
assert(override == NULL
|| override->code != _PyXI_ERR_UNCAUGHT_EXCEPTION);
}
else if (override == NULL) {
// This is equivalent to _PyXI_ERR_UNCAUGHT_EXCEPTION.
}
else if (override->code == _PyXI_ERR_UNCAUGHT_EXCEPTION) {
// We want to actually capture the current exception.
}
else if (exc != NULL) {
// It might make sense to do similarly for other codes.
if (override->code == _PyXI_ERR_ALREADY_RUNNING) {
// We don't need the exception info.
Py_CLEAR(exc);
}
// ...else we want to actually capture the current exception.
}
return exc;
}
static void
xi_error_set_override(PyThreadState *tstate, _PyXI_error *err,
_PyXI_failure *override)
{
assert(err->override == NULL);
assert(override != NULL);
assert(override->code != _PyXI_ERR_NO_ERROR);
// Use xi_error_set_exc() instead of setting _PyXI_ERR_UNCAUGHT_EXCEPTION..
assert(override->code != _PyXI_ERR_UNCAUGHT_EXCEPTION);
err->override = &err->_override;
// The caller still owns override->msg.
copy_xi_failure(&err->_override, override);
err->interp = tstate->interp;
}
static void
xi_error_set_override_code(PyThreadState *tstate, _PyXI_error *err,
_PyXI_errcode code)
{
_PyXI_failure override = XI_FAILURE_INIT;
override.code = code;
xi_error_set_override(tstate, err, &override);
}
static const char *
xi_error_set_exc(PyThreadState *tstate, _PyXI_error *err, PyObject *exc)
{
assert(!_PyErr_Occurred(tstate));
assert(!xi_error_is_set(err));
assert(err->override == NULL);
assert(err->interp == NULL);
assert(exc != NULL);
const char *failure =
_PyXI_excinfo_InitFromException(&err->uncaught, exc);
if (failure != NULL) {
// We failed to initialize err->uncaught.
// XXX Print the excobj/traceback? Emit a warning?
// XXX Print the current exception/traceback?
if (_PyErr_ExceptionMatches(tstate, PyExc_MemoryError)) {
xi_error_set_override_code(tstate, err, _PyXI_ERR_NO_MEMORY);
}
else {
xi_error_set_override_code(tstate, err, _PyXI_ERR_OTHER);
}
PyErr_Clear();
}
return failure;
}
static PyObject *
_PyXI_ApplyError(_PyXI_error *error, const char *failure)
{
PyThreadState *tstate = PyThreadState_Get();
if (failure != NULL) {
xi_error_clear(error);
return NULL;
}
_PyXI_errcode code = _PyXI_ERR_UNCAUGHT_EXCEPTION;
if (error->override != NULL) {
code = error->override->code;
assert(code != _PyXI_ERR_NO_ERROR);
}
if (code == _PyXI_ERR_UNCAUGHT_EXCEPTION) {
// We will raise an exception that proxies the propagated exception.
return _PyXI_excinfo_AsObject(&error->uncaught);
}
else if (code == _PyXI_ERR_NOT_SHAREABLE) {
// Propagate the exception directly.
assert(!_PyErr_Occurred(tstate));
PyObject *cause = NULL;
if (excinfo_is_set(&error->uncaught)) {
// Maybe instead set a PyExc_ExceptionSnapshot as __cause__?
// That type doesn't exist currently
// but would look like interpreters.ExecutionFailed.
_PyXI_excinfo_Apply(&error->uncaught, PyExc_Exception);
cause = _PyErr_GetRaisedException(tstate);
}
const char *msg = error->override != NULL
? error->override->msg
: error->uncaught.msg;
_set_xid_lookup_failure(tstate, NULL, msg, cause);
Py_XDECREF(cause);
}
else {
// Raise an exception corresponding to the code.
(void)_PyXI_ApplyErrorCode(code, error->interp);
assert(error->override == NULL || error->override->msg == NULL);
if (excinfo_is_set(&error->uncaught)) {
// __context__ will be set to a proxy of the propagated exception.
// (or use PyExc_ExceptionSnapshot like _PyXI_ERR_NOT_SHAREABLE?)
PyObject *exc = _PyErr_GetRaisedException(tstate);
_PyXI_excinfo_Apply(&error->uncaught, PyExc_InterpreterError);
PyObject *exc2 = _PyErr_GetRaisedException(tstate);
PyException_SetContext(exc, exc2);
_PyErr_SetRaisedException(tstate, exc);
}
}
assert(PyErr_Occurred());
return NULL;
}
/* shared namespaces */
/* Shared namespaces are expected to have relatively short lifetimes.
This means dealloc of a shared namespace will normally happen "soon".
Namespace items hold cross-interpreter data, which must get released.
If the namespace/items are cleared in a different interpreter than
where the items' cross-interpreter data was set then that will cause
pending calls to be used to release the cross-interpreter data.
The tricky bit is that the pending calls can happen sufficiently
later that the namespace/items might already be deallocated. This is
a problem if the cross-interpreter data is allocated as part of a
namespace item. If that's the case then we must ensure the shared
namespace is only cleared/freed *after* that data has been released. */
typedef struct _sharednsitem {
const char *name;
_PyXIData_t *xidata;
// We could have a "PyXIData _data" field, so it would
// be allocated as part of the item and avoid an extra allocation.
// However, doing so adds a bunch of complexity because we must
// ensure the item isn't freed before a pending call might happen
// in a different interpreter to release the XI data.
} _PyXI_namespace_item;
#ifndef NDEBUG
static int
_sharednsitem_is_initialized(_PyXI_namespace_item *item)
{
if (item->name != NULL) {
return 1;
}
return 0;
}
#endif
static int
_sharednsitem_init(_PyXI_namespace_item *item, PyObject *key)
{
item->name = _copy_string_obj_raw(key, NULL);
if (item->name == NULL) {
assert(!_sharednsitem_is_initialized(item));
return -1;
}
item->xidata = NULL;
assert(_sharednsitem_is_initialized(item));
return 0;
}
static int
_sharednsitem_has_value(_PyXI_namespace_item *item, int64_t *p_interpid)
{
if (item->xidata == NULL) {
return 0;
}
if (p_interpid != NULL) {
*p_interpid = _PyXIData_INTERPID(item->xidata);
}
return 1;
}
static int
_sharednsitem_set_value(_PyXI_namespace_item *item, PyObject *value,
xidata_fallback_t fallback)
{
assert(_sharednsitem_is_initialized(item));
assert(item->xidata == NULL);
item->xidata = _PyXIData_New();
if (item->xidata == NULL) {
return -1;
}
PyThreadState *tstate = PyThreadState_Get();
if (_PyObject_GetXIData(tstate, value, fallback, item->xidata) < 0) {
PyMem_RawFree(item->xidata);
item->xidata = NULL;
// The caller may want to propagate PyExc_NotShareableError
// if currently switched between interpreters.
return -1;
}
return 0;
}
static void
_sharednsitem_clear_value(_PyXI_namespace_item *item)
{
_PyXIData_t *xidata = item->xidata;
if (xidata != NULL) {
item->xidata = NULL;
int rawfree = 1;
(void)_release_xid_data(xidata, rawfree);
}
}
static void
_sharednsitem_clear(_PyXI_namespace_item *item)
{
if (item->name != NULL) {
PyMem_RawFree((void *)item->name);
item->name = NULL;
}
_sharednsitem_clear_value(item);
}
static int
_sharednsitem_copy_from_ns(struct _sharednsitem *item, PyObject *ns,
xidata_fallback_t fallback)
{
assert(item->name != NULL);
assert(item->xidata == NULL);
PyObject *value = PyDict_GetItemString(ns, item->name); // borrowed
if (value == NULL) {
if (PyErr_Occurred()) {
return -1;
}
// When applied, this item will be set to the default (or fail).
return 0;
}
if (_sharednsitem_set_value(item, value, fallback) < 0) {
return -1;
}
return 0;
}
static int
_sharednsitem_apply(_PyXI_namespace_item *item, PyObject *ns, PyObject *dflt)
{
PyObject *name = PyUnicode_FromString(item->name);
if (name == NULL) {
return -1;
}
PyObject *value;
if (item->xidata != NULL) {
value = _PyXIData_NewObject(item->xidata);
if (value == NULL) {
Py_DECREF(name);
return -1;
}
}
else {
value = Py_NewRef(dflt);
}
int res = PyDict_SetItem(ns, name, value);
Py_DECREF(name);
Py_DECREF(value);
return res;
}
typedef struct {
Py_ssize_t maxitems;
Py_ssize_t numnames;
Py_ssize_t numvalues;
_PyXI_namespace_item items[1];
} _PyXI_namespace;
#ifndef NDEBUG
static int
_sharedns_check_counts(_PyXI_namespace *ns)
{
if (ns->maxitems <= 0) {
return 0;
}
if (ns->numnames < 0) {
return 0;
}
if (ns->numnames > ns->maxitems) {
return 0;
}
if (ns->numvalues < 0) {
return 0;
}
if (ns->numvalues > ns->numnames) {
return 0;
}
return 1;
}
static int
_sharedns_check_consistency(_PyXI_namespace *ns)
{
if (!_sharedns_check_counts(ns)) {
return 0;
}
Py_ssize_t i = 0;
_PyXI_namespace_item *item;
if (ns->numvalues > 0) {
item = &ns->items[0];
if (!_sharednsitem_is_initialized(item)) {
return 0;
}
int64_t interpid0 = -1;
if (!_sharednsitem_has_value(item, &interpid0)) {
return 0;
}
i += 1;
for (; i < ns->numvalues; i++) {
item = &ns->items[i];
if (!_sharednsitem_is_initialized(item)) {
return 0;
}
int64_t interpid = -1;
if (!_sharednsitem_has_value(item, &interpid)) {
return 0;
}
if (interpid != interpid0) {
return 0;
}
}
}
for (; i < ns->numnames; i++) {
item = &ns->items[i];
if (!_sharednsitem_is_initialized(item)) {
return 0;
}
if (_sharednsitem_has_value(item, NULL)) {
return 0;
}
}
for (; i < ns->maxitems; i++) {
item = &ns->items[i];
if (_sharednsitem_is_initialized(item)) {
return 0;
}
if (_sharednsitem_has_value(item, NULL)) {
return 0;
}
}
return 1;
}
#endif
static _PyXI_namespace *
_sharedns_alloc(Py_ssize_t maxitems)
{
if (maxitems < 0) {
if (!PyErr_Occurred()) {
PyErr_BadInternalCall();
}
return NULL;
}
else if (maxitems == 0) {
PyErr_SetString(PyExc_ValueError, "empty namespaces not allowed");
return NULL;
}
// Check for overflow.
size_t fixedsize = sizeof(_PyXI_namespace) - sizeof(_PyXI_namespace_item);
if ((size_t)maxitems >
((size_t)PY_SSIZE_T_MAX - fixedsize) / sizeof(_PyXI_namespace_item))
{
PyErr_NoMemory();
return NULL;
}
// Allocate the value, including items.
size_t size = fixedsize + sizeof(_PyXI_namespace_item) * maxitems;
_PyXI_namespace *ns = PyMem_RawCalloc(size, 1);
if (ns == NULL) {
PyErr_NoMemory();
return NULL;
}
ns->maxitems = maxitems;
assert(_sharedns_check_consistency(ns));
return ns;
}
static void
_sharedns_free(_PyXI_namespace *ns)
{
// If we weren't always dynamically allocating the cross-interpreter
// data in each item then we would need to use a pending call
// to call _sharedns_free(), to avoid the race between freeing
// the shared namespace and releasing the XI data.
assert(_sharedns_check_counts(ns));
Py_ssize_t i = 0;
_PyXI_namespace_item *item;
if (ns->numvalues > 0) {
// One or more items may have interpreter-specific data.
#ifndef NDEBUG
int64_t interpid = PyInterpreterState_GetID(PyInterpreterState_Get());
int64_t interpid_i;
#endif
for (; i < ns->numvalues; i++) {
item = &ns->items[i];
assert(_sharednsitem_is_initialized(item));
// While we do want to ensure consistency across items,
// technically they don't need to match the current
// interpreter. However, we keep the constraint for
// simplicity, by giving _PyXI_FreeNamespace() the exclusive
// responsibility of dealing with the owning interpreter.
assert(_sharednsitem_has_value(item, &interpid_i));
assert(interpid_i == interpid);
_sharednsitem_clear(item);
}
}
for (; i < ns->numnames; i++) {
item = &ns->items[i];
assert(_sharednsitem_is_initialized(item));
assert(!_sharednsitem_has_value(item, NULL));
_sharednsitem_clear(item);
}
#ifndef NDEBUG
for (; i < ns->maxitems; i++) {
item = &ns->items[i];
assert(!_sharednsitem_is_initialized(item));
assert(!_sharednsitem_has_value(item, NULL));
}
#endif
PyMem_RawFree(ns);
}
static _PyXI_namespace *
_create_sharedns(PyObject *names)
{
assert(names != NULL);
Py_ssize_t numnames = PyDict_CheckExact(names)
? PyDict_Size(names)
: PySequence_Size(names);
_PyXI_namespace *ns = _sharedns_alloc(numnames);
if (ns == NULL) {
return NULL;
}
_PyXI_namespace_item *items = ns->items;
// Fill in the names.
if (PyDict_CheckExact(names)) {
Py_ssize_t i = 0;
Py_ssize_t pos = 0;
PyObject *name;
while(PyDict_Next(names, &pos, &name, NULL)) {
if (_sharednsitem_init(&items[i], name) < 0) {
goto error;
}
ns->numnames += 1;
i += 1;
}
}
else if (PySequence_Check(names)) {
for (Py_ssize_t i = 0; i < numnames; i++) {
PyObject *name = PySequence_GetItem(names, i);
if (name == NULL) {
goto error;
}
int res = _sharednsitem_init(&items[i], name);
Py_DECREF(name);
if (res < 0) {
goto error;
}
ns->numnames += 1;
}
}
else {
PyErr_SetString(PyExc_NotImplementedError,
"non-sequence namespace not supported");
goto error;
}
assert(ns->numnames == ns->maxitems);
return ns;
error:
_sharedns_free(ns);
return NULL;
}
static void _propagate_not_shareable_error(PyThreadState *,
_PyXI_failure *);
static int
_fill_sharedns(_PyXI_namespace *ns, PyObject *nsobj,
xidata_fallback_t fallback, _PyXI_failure *p_err)
{
// All items are expected to be shareable.
assert(_sharedns_check_counts(ns));
assert(ns->numnames == ns->maxitems);
assert(ns->numvalues == 0);
PyThreadState *tstate = PyThreadState_Get();
for (Py_ssize_t i=0; i < ns->maxitems; i++) {
if (_sharednsitem_copy_from_ns(&ns->items[i], nsobj, fallback) < 0) {
if (p_err != NULL) {
_propagate_not_shareable_error(tstate, p_err);
}
// Clear out the ones we set so far.
for (Py_ssize_t j=0; j < i; j++) {
_sharednsitem_clear_value(&ns->items[j]);
ns->numvalues -= 1;
}
return -1;
}
ns->numvalues += 1;
}
return 0;
}
static int
_sharedns_free_pending(void *data)
{
_sharedns_free((_PyXI_namespace *)data);
return 0;
}
static void
_destroy_sharedns(_PyXI_namespace *ns)
{
assert(_sharedns_check_counts(ns));
assert(ns->numnames == ns->maxitems);
if (ns->numvalues == 0) {
_sharedns_free(ns);
return;
}
int64_t interpid0;
if (!_sharednsitem_has_value(&ns->items[0], &interpid0)) {
// This shouldn't have been possible.
// We can deal with it in _sharedns_free().
_sharedns_free(ns);
return;
}
PyInterpreterState *interp = _PyInterpreterState_LookUpID(interpid0);
if (interp == PyInterpreterState_Get()) {
_sharedns_free(ns);
return;
}
// One or more items may have interpreter-specific data.
// Currently the xidata for each value is dynamically allocated,
// so technically we don't need to worry about that.
// However, explicitly adding a pending call here is simpler.
(void)_Py_CallInInterpreter(interp, _sharedns_free_pending, ns);
}
static int
_apply_sharedns(_PyXI_namespace *ns, PyObject *nsobj, PyObject *dflt)
{
for (Py_ssize_t i=0; i < ns->maxitems; i++) {
if (_sharednsitem_apply(&ns->items[i], nsobj, dflt) != 0) {
return -1;
}
}
return 0;
}
/*********************************/
/* switched-interpreter sessions */
/*********************************/
struct xi_session {
#define SESSION_UNUSED 0
#define SESSION_ACTIVE 1
int status;
int switched;
// Once a session has been entered, this is the tstate that was
// current before the session. If it is different from cur_tstate
// then we must have switched interpreters. Either way, this will
// be the current tstate once we exit the session.
PyThreadState *prev_tstate;
// Once a session has been entered, this is the current tstate.
// It must be current when the session exits.
PyThreadState *init_tstate;
// This is true if init_tstate needs cleanup during exit.
int own_init_tstate;
// This is true if, while entering the session, init_thread took
// "ownership" of the interpreter's __main__ module. This means
// it is the only thread that is allowed to run code there.
// (Caveat: for now, users may still run exec() against the
// __main__ module's dict, though that isn't advisable.)
int running;
// This is a cached reference to the __dict__ of the entered
// interpreter's __main__ module. It is looked up when at the
// beginning of the session as a convenience.
PyObject *main_ns;
// This is a dict of objects that will be available (via sharing)
// once the session exits. Do not access this directly; use
// _PyXI_Preserve() and _PyXI_GetPreserved() instead;
PyObject *_preserved;
};
_PyXI_session *
_PyXI_NewSession(void)
{
_PyXI_session *session = PyMem_RawCalloc(1, sizeof(_PyXI_session));
if (session == NULL) {
PyErr_NoMemory();
return NULL;
}
return session;
}
void
_PyXI_FreeSession(_PyXI_session *session)
{
assert(session->status == SESSION_UNUSED);
PyMem_RawFree(session);
}
static inline int
_session_is_active(_PyXI_session *session)
{
return session->status == SESSION_ACTIVE;
}
/* enter/exit a cross-interpreter session */
static void
_enter_session(_PyXI_session *session, PyInterpreterState *interp)
{
// Set here and cleared in _exit_session().
assert(session->status == SESSION_UNUSED);
assert(!session->own_init_tstate);
assert(session->init_tstate == NULL);
assert(session->prev_tstate == NULL);
// Set elsewhere and cleared in _exit_session().
assert(!session->running);
assert(session->main_ns == NULL);
// Switch to interpreter.
PyThreadState *tstate = PyThreadState_Get();
PyThreadState *prev = tstate;
int same_interp = (interp == tstate->interp);
if (!same_interp) {
tstate = _PyThreadState_NewBound(interp, _PyThreadState_WHENCE_EXEC);
// XXX Possible GILState issues?
PyThreadState *swapped = PyThreadState_Swap(tstate);
assert(swapped == prev);
(void)swapped;
}
*session = (_PyXI_session){
.status = SESSION_ACTIVE,
.switched = !same_interp,
.init_tstate = tstate,
.prev_tstate = prev,
.own_init_tstate = !same_interp,
};
}
static void
_exit_session(_PyXI_session *session)
{
PyThreadState *tstate = session->init_tstate;
assert(tstate != NULL);
assert(PyThreadState_Get() == tstate);
assert(!_PyErr_Occurred(tstate));
// Release any of the entered interpreters resources.
Py_CLEAR(session->main_ns);
Py_CLEAR(session->_preserved);
// Ensure this thread no longer owns __main__.
if (session->running) {
_PyInterpreterState_SetNotRunningMain(tstate->interp);
assert(!_PyErr_Occurred(tstate));
session->running = 0;
}
// Switch back.
assert(session->prev_tstate != NULL);
if (session->prev_tstate != session->init_tstate) {
assert(session->own_init_tstate);
session->own_init_tstate = 0;
PyThreadState_Clear(tstate);
PyThreadState_Swap(session->prev_tstate);
PyThreadState_Delete(tstate);
}
else {
assert(!session->own_init_tstate);
}
*session = (_PyXI_session){0};
}
static void
_propagate_not_shareable_error(PyThreadState *tstate,
_PyXI_failure *override)
{
assert(override != NULL);
PyObject *exctype = get_notshareableerror_type(tstate);
if (exctype == NULL) {
PyErr_FormatUnraisable(
"Exception ignored while propagating not shareable error");
return;
}
if (PyErr_ExceptionMatches(exctype)) {
// We want to propagate the exception directly.
*override = (_PyXI_failure){
.code = _PyXI_ERR_NOT_SHAREABLE,
};
}
}
static int _ensure_main_ns(_PyXI_session *, _PyXI_failure *);
static const char * capture_session_error(_PyXI_session *, _PyXI_error *,
_PyXI_failure *);
int
_PyXI_Enter(_PyXI_session *session,
PyInterpreterState *interp, PyObject *nsupdates,
_PyXI_session_result *result)
{
#ifndef NDEBUG
PyThreadState *tstate = _PyThreadState_GET(); // Only used for asserts
#endif
// Convert the attrs for cross-interpreter use.
_PyXI_namespace *sharedns = NULL;
if (nsupdates != NULL) {
assert(PyDict_Check(nsupdates));
Py_ssize_t len = PyDict_Size(nsupdates);
if (len < 0) {
if (result != NULL) {
result->errcode = _PyXI_ERR_APPLY_NS_FAILURE;
}
return -1;
}
if (len > 0) {
sharedns = _create_sharedns(nsupdates);
if (sharedns == NULL) {
if (result != NULL) {
result->errcode = _PyXI_ERR_APPLY_NS_FAILURE;
}
return -1;
}
// For now we limit it to shareable objects.
xidata_fallback_t fallback = _PyXIDATA_XIDATA_ONLY;
_PyXI_failure _err = XI_FAILURE_INIT;
if (_fill_sharedns(sharedns, nsupdates, fallback, &_err) < 0) {
assert(_PyErr_Occurred(tstate));
if (_err.code == _PyXI_ERR_NO_ERROR) {
_err.code = _PyXI_ERR_UNCAUGHT_EXCEPTION;
}
_destroy_sharedns(sharedns);
if (result != NULL) {
assert(_err.msg == NULL);
result->errcode = _err.code;
}
return -1;
}
}
}
// Switch to the requested interpreter (if necessary).
_enter_session(session, interp);
_PyXI_failure override = XI_FAILURE_INIT;
override.code = _PyXI_ERR_UNCAUGHT_EXCEPTION;
#ifndef NDEBUG
tstate = _PyThreadState_GET();
#endif
// Ensure this thread owns __main__.
if (_PyInterpreterState_SetRunningMain(interp) < 0) {
// In the case where we didn't switch interpreters, it would
// be more efficient to leave the exception in place and return
// immediately. However, life is simpler if we don't.
override.code = _PyXI_ERR_ALREADY_RUNNING;
goto error;
}
session->running = 1;
// Apply the cross-interpreter data.
if (sharedns != NULL) {
if (_ensure_main_ns(session, &override) < 0) {
goto error;
}
if (_apply_sharedns(sharedns, session->main_ns, NULL) < 0) {
override.code = _PyXI_ERR_APPLY_NS_FAILURE;
goto error;
}
_destroy_sharedns(sharedns);
}
override.code = _PyXI_ERR_NO_ERROR;
assert(!_PyErr_Occurred(tstate));
return 0;
error:
// We want to propagate all exceptions here directly (best effort).
assert(override.code != _PyXI_ERR_NO_ERROR);
_PyXI_error err = {0};
const char *failure = capture_session_error(session, &err, &override);
// Exit the session.
_exit_session(session);
#ifndef NDEBUG
tstate = _PyThreadState_GET();
#endif
if (sharedns != NULL) {
_destroy_sharedns(sharedns);
}
// Apply the error from the other interpreter.
PyObject *excinfo = _PyXI_ApplyError(&err, failure);
xi_error_clear(&err);
if (excinfo != NULL) {
if (result != NULL) {
result->excinfo = excinfo;
}
else {
#ifdef Py_DEBUG
fprintf(stderr, "_PyXI_Enter(): uncaught exception discarded");
#endif
Py_DECREF(excinfo);
}
}
assert(_PyErr_Occurred(tstate));
return -1;
}
static int _pop_preserved(_PyXI_session *, _PyXI_namespace **, PyObject **,
_PyXI_failure *);
static int _finish_preserved(_PyXI_namespace *, PyObject **);
int
_PyXI_Exit(_PyXI_session *session, _PyXI_failure *override,
_PyXI_session_result *result)
{
PyThreadState *tstate = _PyThreadState_GET();
int res = 0;
// Capture the raised exception, if any.
_PyXI_error err = {0};
const char *failure = NULL;
if (override != NULL && override->code == _PyXI_ERR_NO_ERROR) {
assert(override->msg == NULL);
override = NULL;
}
if (_PyErr_Occurred(tstate)) {
failure = capture_session_error(session, &err, override);
}
else {
assert(override == NULL);
}
// Capture the preserved namespace.
_PyXI_namespace *preserved = NULL;
PyObject *preservedobj = NULL;
if (result != NULL) {
assert(!_PyErr_Occurred(tstate));
_PyXI_failure _override = XI_FAILURE_INIT;
if (_pop_preserved(
session, &preserved, &preservedobj, &_override) < 0)
{
assert(preserved == NULL);
assert(preservedobj == NULL);
if (xi_error_is_set(&err)) {
// XXX Chain the exception (i.e. set __context__)?
PyErr_FormatUnraisable(
"Exception ignored while capturing preserved objects");
clear_xi_failure(&_override);
}
else {
if (_override.code == _PyXI_ERR_NO_ERROR) {
_override.code = _PyXI_ERR_UNCAUGHT_EXCEPTION;
}
failure = capture_session_error(session, &err, &_override);
}
}
}
// Exit the session.
assert(!_PyErr_Occurred(tstate));
_exit_session(session);
tstate = _PyThreadState_GET();
// Restore the preserved namespace.
assert(preserved == NULL || preservedobj == NULL);
if (_finish_preserved(preserved, &preservedobj) < 0) {
assert(preservedobj == NULL);
if (xi_error_is_set(&err)) {
// XXX Chain the exception (i.e. set __context__)?
PyErr_FormatUnraisable(
"Exception ignored while capturing preserved objects");
}
else {
xi_error_set_override_code(
tstate, &err, _PyXI_ERR_PRESERVE_FAILURE);
_propagate_not_shareable_error(tstate, err.override);
}
}
if (result != NULL) {
result->preserved = preservedobj;
result->errcode = err.override != NULL
? err.override->code
: _PyXI_ERR_NO_ERROR;
}
// Apply the error from the other interpreter, if any.
if (xi_error_is_set(&err)) {
res = -1;
assert(!_PyErr_Occurred(tstate));
PyObject *excinfo = _PyXI_ApplyError(&err, failure);
if (excinfo == NULL) {
assert(_PyErr_Occurred(tstate));
if (result != NULL && !xi_error_has_override(&err)) {
_PyXI_ClearResult(result);
*result = (_PyXI_session_result){
.errcode = _PyXI_ERR_EXC_PROPAGATION_FAILURE,
};
}
}
else if (result != NULL) {
result->excinfo = excinfo;
}
else {
#ifdef Py_DEBUG
fprintf(stderr, "_PyXI_Exit(): uncaught exception discarded");
#endif
Py_DECREF(excinfo);
}
xi_error_clear(&err);
}
return res;
}
/* in an active cross-interpreter session */
static const char *
capture_session_error(_PyXI_session *session, _PyXI_error *err,
_PyXI_failure *override)
{
assert(_session_is_active(session));
assert(!xi_error_is_set(err));
PyThreadState *tstate = session->init_tstate;
// Normalize the exception override.
if (override != NULL) {
if (override->code == _PyXI_ERR_UNCAUGHT_EXCEPTION) {
assert(override->msg == NULL);
override = NULL;
}
else {
assert(override->code != _PyXI_ERR_NO_ERROR);
}
}
// Handle the exception, if any.
const char *failure = NULL;
PyObject *exc = xi_error_resolve_current_exc(tstate, override);
if (exc != NULL) {
// There is an unhandled exception we need to preserve.
failure = xi_error_set_exc(tstate, err, exc);
Py_DECREF(exc);
if (_PyErr_Occurred(tstate)) {
PyErr_FormatUnraisable(failure);
}
}
// Handle the override.
if (override != NULL && failure == NULL) {
xi_error_set_override(tstate, err, override);
}
// Finished!
assert(!_PyErr_Occurred(tstate));
return failure;
}
static int
_ensure_main_ns(_PyXI_session *session, _PyXI_failure *failure)
{
assert(_session_is_active(session));
PyThreadState *tstate = session->init_tstate;
if (session->main_ns != NULL) {
return 0;
}
// Cache __main__.__dict__.
PyObject *main_mod = _Py_GetMainModule(tstate);
if (_Py_CheckMainModule(main_mod) < 0) {
Py_XDECREF(main_mod);
if (failure != NULL) {
*failure = (_PyXI_failure){
.code = _PyXI_ERR_MAIN_NS_FAILURE,
};
}
return -1;
}
PyObject *ns = PyModule_GetDict(main_mod); // borrowed
Py_DECREF(main_mod);
if (ns == NULL) {
if (failure != NULL) {
*failure = (_PyXI_failure){
.code = _PyXI_ERR_MAIN_NS_FAILURE,
};
}
return -1;
}
session->main_ns = Py_NewRef(ns);
return 0;
}
PyObject *
_PyXI_GetMainNamespace(_PyXI_session *session, _PyXI_failure *failure)
{
if (!_session_is_active(session)) {
PyErr_SetString(PyExc_RuntimeError, "session not active");
return NULL;
}
if (_ensure_main_ns(session, failure) < 0) {
return NULL;
}
return session->main_ns;
}
static int
_pop_preserved(_PyXI_session *session,
_PyXI_namespace **p_xidata, PyObject **p_obj,
_PyXI_failure *p_failure)
{
_PyXI_failure failure = XI_FAILURE_INIT;
_PyXI_namespace *xidata = NULL;
assert(_PyThreadState_GET() == session->init_tstate); // active session
if (session->_preserved == NULL) {
*p_xidata = NULL;
*p_obj = NULL;
return 0;
}
if (session->init_tstate == session->prev_tstate) {
// We did not switch interpreters.
*p_xidata = NULL;
*p_obj = session->_preserved;
session->_preserved = NULL;
return 0;
}
*p_obj = NULL;
// We did switch interpreters.
Py_ssize_t len = PyDict_Size(session->_preserved);
if (len < 0) {
failure.code = _PyXI_ERR_PRESERVE_FAILURE;
goto error;
}
else if (len == 0) {
*p_xidata = NULL;
}
else {
_PyXI_namespace *xidata = _create_sharedns(session->_preserved);
if (xidata == NULL) {
failure.code = _PyXI_ERR_PRESERVE_FAILURE;
goto error;
}
if (_fill_sharedns(xidata, session->_preserved,
_PyXIDATA_FULL_FALLBACK, &failure) < 0)
{
if (failure.code != _PyXI_ERR_NOT_SHAREABLE) {
assert(failure.msg != NULL);
failure.code = _PyXI_ERR_PRESERVE_FAILURE;
}
goto error;
}
*p_xidata = xidata;
}
Py_CLEAR(session->_preserved);
return 0;
error:
if (p_failure != NULL) {
*p_failure = failure;
}
if (xidata != NULL) {
_destroy_sharedns(xidata);
}
return -1;
}
static int
_finish_preserved(_PyXI_namespace *xidata, PyObject **p_preserved)
{
if (xidata == NULL) {
return 0;
}
int res = -1;
if (p_preserved != NULL) {
PyObject *ns = PyDict_New();
if (ns == NULL) {
goto finally;
}
if (_apply_sharedns(xidata, ns, NULL) < 0) {
Py_CLEAR(ns);
goto finally;
}
*p_preserved = ns;
}
res = 0;
finally:
_destroy_sharedns(xidata);
return res;
}
int
_PyXI_Preserve(_PyXI_session *session, const char *name, PyObject *value,
_PyXI_failure *p_failure)
{
_PyXI_failure failure = XI_FAILURE_INIT;
if (!_session_is_active(session)) {
PyErr_SetString(PyExc_RuntimeError, "session not active");
return -1;
}
if (session->_preserved == NULL) {
session->_preserved = PyDict_New();
if (session->_preserved == NULL) {
set_exc_with_cause(PyExc_RuntimeError,
"failed to initialize preserved objects");
failure.code = _PyXI_ERR_PRESERVE_FAILURE;
goto error;
}
}
if (PyDict_SetItemString(session->_preserved, name, value) < 0) {
set_exc_with_cause(PyExc_RuntimeError, "failed to preserve object");
failure.code = _PyXI_ERR_PRESERVE_FAILURE;
goto error;
}
return 0;
error:
if (p_failure != NULL) {
*p_failure = failure;
}
return -1;
}
PyObject *
_PyXI_GetPreserved(_PyXI_session_result *result, const char *name)
{
PyObject *value = NULL;
if (result->preserved != NULL) {
(void)PyDict_GetItemStringRef(result->preserved, name, &value);
}
return value;
}
void
_PyXI_ClearResult(_PyXI_session_result *result)
{
Py_CLEAR(result->preserved);
Py_CLEAR(result->excinfo);
}
/*********************/
/* runtime lifecycle */
/*********************/
int
_Py_xi_global_state_init(_PyXI_global_state_t *state)
{
assert(state != NULL);
xid_lookup_init(&state->data_lookup);
return 0;
}
void
_Py_xi_global_state_fini(_PyXI_global_state_t *state)
{
assert(state != NULL);
xid_lookup_fini(&state->data_lookup);
}
int
_Py_xi_state_init(_PyXI_state_t *state, PyInterpreterState *interp)
{
assert(state != NULL);
assert(interp == NULL || state == _PyXI_GET_STATE(interp));
xid_lookup_init(&state->data_lookup);
// Initialize exceptions.
if (interp != NULL) {
if (init_static_exctypes(&state->exceptions, interp) < 0) {
fini_heap_exctypes(&state->exceptions);
return -1;
}
}
if (init_heap_exctypes(&state->exceptions) < 0) {
return -1;
}
return 0;
}
void
_Py_xi_state_fini(_PyXI_state_t *state, PyInterpreterState *interp)
{
assert(state != NULL);
assert(interp == NULL || state == _PyXI_GET_STATE(interp));
fini_heap_exctypes(&state->exceptions);
if (interp != NULL) {
fini_static_exctypes(&state->exceptions, interp);
}
xid_lookup_fini(&state->data_lookup);
}
PyStatus
_PyXI_Init(PyInterpreterState *interp)
{
if (_Py_IsMainInterpreter(interp)) {
_PyXI_global_state_t *global_state = _PyXI_GET_GLOBAL_STATE(interp);
if (global_state == NULL) {
PyErr_PrintEx(0);
return _PyStatus_ERR(
"failed to get global cross-interpreter state");
}
if (_Py_xi_global_state_init(global_state) < 0) {
PyErr_PrintEx(0);
return _PyStatus_ERR(
"failed to initialize global cross-interpreter state");
}
}
_PyXI_state_t *state = _PyXI_GET_STATE(interp);
if (state == NULL) {
PyErr_PrintEx(0);
return _PyStatus_ERR(
"failed to get interpreter's cross-interpreter state");
}
// The static types were already initialized in _PyXI_InitTypes(),
// so we pass in NULL here to avoid initializing them again.
if (_Py_xi_state_init(state, NULL) < 0) {
PyErr_PrintEx(0);
return _PyStatus_ERR(
"failed to initialize interpreter's cross-interpreter state");
}
return _PyStatus_OK();
}
// _PyXI_Fini() must be called before the interpreter is cleared,
// since we must clear some heap objects.
void
_PyXI_Fini(PyInterpreterState *interp)
{
_PyXI_state_t *state = _PyXI_GET_STATE(interp);
#ifndef NDEBUG
if (state == NULL) {
PyErr_PrintEx(0);
return;
}
#endif
// The static types will be finalized soon in _PyXI_FiniTypes(),
// so we pass in NULL here to avoid finalizing them right now.
_Py_xi_state_fini(state, NULL);
if (_Py_IsMainInterpreter(interp)) {
_PyXI_global_state_t *global_state = _PyXI_GET_GLOBAL_STATE(interp);
_Py_xi_global_state_fini(global_state);
}
}
PyStatus
_PyXI_InitTypes(PyInterpreterState *interp)
{
if (init_static_exctypes(&_PyXI_GET_STATE(interp)->exceptions, interp) < 0) {
PyErr_PrintEx(0);
return _PyStatus_ERR(
"failed to initialize the cross-interpreter exception types");
}
// We would initialize heap types here too but that leads to ref leaks.
// Instead, we intialize them in _PyXI_Init().
return _PyStatus_OK();
}
void
_PyXI_FiniTypes(PyInterpreterState *interp)
{
// We would finalize heap types here too but that leads to ref leaks.
// Instead, we finalize them in _PyXI_Fini().
fini_static_exctypes(&_PyXI_GET_STATE(interp)->exceptions, interp);
}
/*************/
/* other API */
/*************/
PyInterpreterState *
_PyXI_NewInterpreter(PyInterpreterConfig *config, long *maybe_whence,
PyThreadState **p_tstate, PyThreadState **p_save_tstate)
{
PyThreadState *save_tstate = PyThreadState_Swap(NULL);
assert(save_tstate != NULL);
PyThreadState *tstate;
PyStatus status = Py_NewInterpreterFromConfig(&tstate, config);
if (PyStatus_Exception(status)) {
// Since no new thread state was created, there is no exception
// to propagate; raise a fresh one after swapping back in the
// old thread state.
PyThreadState_Swap(save_tstate);
_PyErr_SetFromPyStatus(status);
PyObject *exc = PyErr_GetRaisedException();
PyErr_SetString(PyExc_InterpreterError,
"sub-interpreter creation failed");
_PyErr_ChainExceptions1(exc);
return NULL;
}
assert(tstate != NULL);
PyInterpreterState *interp = PyThreadState_GetInterpreter(tstate);
long whence = _PyInterpreterState_WHENCE_XI;
if (maybe_whence != NULL) {
whence = *maybe_whence;
}
_PyInterpreterState_SetWhence(interp, whence);
if (p_tstate != NULL) {
// We leave the new thread state as the current one.
*p_tstate = tstate;
}
else {
// Throw away the initial tstate.
PyThreadState_Clear(tstate);
PyThreadState_Swap(save_tstate);
PyThreadState_Delete(tstate);
save_tstate = NULL;
}
if (p_save_tstate != NULL) {
*p_save_tstate = save_tstate;
}
return interp;
}
void
_PyXI_EndInterpreter(PyInterpreterState *interp,
PyThreadState *tstate, PyThreadState **p_save_tstate)
{
#ifndef NDEBUG
long whence = _PyInterpreterState_GetWhence(interp);
#endif
assert(whence != _PyInterpreterState_WHENCE_RUNTIME);
if (!_PyInterpreterState_IsReady(interp)) {
assert(whence == _PyInterpreterState_WHENCE_UNKNOWN);
// PyInterpreterState_Clear() requires the GIL,
// which a not-ready does not have, so we don't clear it.
// That means there may be leaks here until clearing the
// interpreter is fixed.
PyInterpreterState_Delete(interp);
return;
}
assert(whence != _PyInterpreterState_WHENCE_UNKNOWN);
PyThreadState *save_tstate = NULL;
PyThreadState *cur_tstate = PyThreadState_GET();
if (tstate == NULL) {
if (PyThreadState_GetInterpreter(cur_tstate) == interp) {
tstate = cur_tstate;
}
else {
tstate = _PyThreadState_NewBound(interp, _PyThreadState_WHENCE_FINI);
assert(tstate != NULL);
save_tstate = PyThreadState_Swap(tstate);
}
}
else {
assert(PyThreadState_GetInterpreter(tstate) == interp);
if (tstate != cur_tstate) {
assert(PyThreadState_GetInterpreter(cur_tstate) != interp);
save_tstate = PyThreadState_Swap(tstate);
}
}
Py_EndInterpreter(tstate);
if (p_save_tstate != NULL) {
save_tstate = *p_save_tstate;
}
PyThreadState_Swap(save_tstate);
}
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