[Python-checkins] gh-81057: Move PyImport_Inittab to _PyRuntimeState (gh-99402)
ericsnowcurrently
webhook-mailer at python.org
Fri Nov 11 19:06:13 EST 2022
https://github.com/python/cpython/commit/7f3a4b967cfb1596a3fda6c34f900f8586b16700
commit: 7f3a4b967cfb1596a3fda6c34f900f8586b16700
branch: main
author: Eric Snow <ericsnowcurrently at gmail.com>
committer: ericsnowcurrently <ericsnowcurrently at gmail.com>
date: 2022-11-11T17:06:05-07:00
summary:
gh-81057: Move PyImport_Inittab to _PyRuntimeState (gh-99402)
We actually don't move PyImport_Inittab. Instead, we make a copy that we keep on _PyRuntimeState and use only that after Py_Initialize(). We also prevent folks from modifying PyImport_Inittab (the best we can) after that point.
https://github.com/python/cpython/issues/81057
files:
A Misc/NEWS.d/next/Core and Builtins/2022-11-11-14-48-17.gh-issue-81057.ik4iOv.rst
M Include/cpython/import.h
M Include/internal/pycore_import.h
M Include/internal/pycore_pylifecycle.h
M Python/import.c
M Python/pylifecycle.c
M Python/sysmodule.c
M Tools/c-analyzer/cpython/globals-to-fix.tsv
M Tools/c-analyzer/cpython/ignored.tsv
diff --git a/Include/cpython/import.h b/Include/cpython/import.h
index a69b4f34def3..a58801b47f1b 100644
--- a/Include/cpython/import.h
+++ b/Include/cpython/import.h
@@ -25,6 +25,7 @@ struct _inittab {
const char *name; /* ASCII encoded string */
PyObject* (*initfunc)(void);
};
+// This is not used after Py_Initialize() is called.
PyAPI_DATA(struct _inittab *) PyImport_Inittab;
PyAPI_FUNC(int) PyImport_ExtendInittab(struct _inittab *newtab);
diff --git a/Include/internal/pycore_import.h b/Include/internal/pycore_import.h
index 7f1240f7c9db..7e8d73be5b9a 100644
--- a/Include/internal/pycore_import.h
+++ b/Include/internal/pycore_import.h
@@ -7,6 +7,8 @@ extern "C" {
struct _import_runtime_state {
+ /* The builtin modules (defined in config.c). */
+ struct _inittab *inittab;
/* The most recent value assigned to a PyModuleDef.m_base.m_index.
This is incremented each time PyModuleDef_Init() is called,
which is just about every time an extension module is imported.
diff --git a/Include/internal/pycore_pylifecycle.h b/Include/internal/pycore_pylifecycle.h
index b4718b8ade23..85bf166d92fd 100644
--- a/Include/internal/pycore_pylifecycle.h
+++ b/Include/internal/pycore_pylifecycle.h
@@ -33,6 +33,7 @@ PyAPI_FUNC(int) _Py_IsLocaleCoercionTarget(const char *ctype_loc);
/* Various one-time initializers */
+extern PyStatus _PyImport_Init(void);
extern PyStatus _PyFaulthandler_Init(int enable);
extern int _PyTraceMalloc_Init(int enable);
extern PyObject * _PyBuiltin_Init(PyInterpreterState *interp);
diff --git a/Misc/NEWS.d/next/Core and Builtins/2022-11-11-14-48-17.gh-issue-81057.ik4iOv.rst b/Misc/NEWS.d/next/Core and Builtins/2022-11-11-14-48-17.gh-issue-81057.ik4iOv.rst
new file mode 100644
index 000000000000..7474cee0c872
--- /dev/null
+++ b/Misc/NEWS.d/next/Core and Builtins/2022-11-11-14-48-17.gh-issue-81057.ik4iOv.rst
@@ -0,0 +1,6 @@
+The docs clearly say that ``PyImport_Inittab``,
+:c:func:`PyImport_AppendInittab`, and :c:func:`PyImport_ExtendInittab`
+should not be used after :c:func:`Py_Initialize` has been called.
+We now enforce this for the two functions. Additionally, the runtime
+now uses an internal copy of ``PyImport_Inittab``,
+to guard against modification.
diff --git a/Python/import.c b/Python/import.c
index d16161381a97..daee16ec4ddd 100644
--- a/Python/import.c
+++ b/Python/import.c
@@ -30,7 +30,11 @@ static PyObject *import_add_module(PyThreadState *tstate, PyObject *name);
/* This table is defined in config.c: */
extern struct _inittab _PyImport_Inittab[];
+// This is not used after Py_Initialize() is called.
+// (See _PyRuntimeState.imports.inittab.)
struct _inittab *PyImport_Inittab = _PyImport_Inittab;
+// When we dynamically allocate a larger table for PyImport_ExtendInittab(),
+// we track the pointer here so we can deallocate it during finalization.
static struct _inittab *inittab_copy = NULL;
/*[clinic input]
@@ -218,6 +222,38 @@ _imp_release_lock_impl(PyObject *module)
Py_RETURN_NONE;
}
+PyStatus
+_PyImport_Init(void)
+{
+ if (_PyRuntime.imports.inittab != NULL) {
+ return _PyStatus_ERR("global import state already initialized");
+ }
+ PyStatus status = _PyStatus_OK();
+
+ size_t size;
+ for (size = 0; PyImport_Inittab[size].name != NULL; size++)
+ ;
+ size++;
+
+ /* Force default raw memory allocator to get a known allocator to be able
+ to release the memory in _PyImport_Fini() */
+ PyMemAllocatorEx old_alloc;
+ _PyMem_SetDefaultAllocator(PYMEM_DOMAIN_RAW, &old_alloc);
+
+ /* Make the copy. */
+ struct _inittab *copied = PyMem_RawMalloc(size * sizeof(struct _inittab));
+ if (copied == NULL) {
+ status = PyStatus_NoMemory();
+ goto done;
+ }
+ memcpy(copied, PyImport_Inittab, size * sizeof(struct _inittab));
+ _PyRuntime.imports.inittab = copied;
+
+done:
+ PyMem_SetAllocator(PYMEM_DOMAIN_RAW, &old_alloc);
+ return status;
+}
+
static inline void _extensions_cache_clear(void);
void
@@ -228,6 +264,17 @@ _PyImport_Fini(void)
PyThread_free_lock(import_lock);
import_lock = NULL;
}
+
+ /* Use the same memory allocator as _PyImport_Init(). */
+ PyMemAllocatorEx old_alloc;
+ _PyMem_SetDefaultAllocator(PYMEM_DOMAIN_RAW, &old_alloc);
+
+ /* Free memory allocated by _PyImport_Init() */
+ struct _inittab *inittab = _PyRuntime.imports.inittab;
+ _PyRuntime.imports.inittab = NULL;
+ PyMem_RawFree(inittab);
+
+ PyMem_SetAllocator(PYMEM_DOMAIN_RAW, &old_alloc);
}
void
@@ -889,9 +936,10 @@ static int
is_builtin(PyObject *name)
{
int i;
- for (i = 0; PyImport_Inittab[i].name != NULL; i++) {
- if (_PyUnicode_EqualToASCIIString(name, PyImport_Inittab[i].name)) {
- if (PyImport_Inittab[i].initfunc == NULL)
+ struct _inittab *inittab = _PyRuntime.imports.inittab;
+ for (i = 0; inittab[i].name != NULL; i++) {
+ if (_PyUnicode_EqualToASCIIString(name, inittab[i].name)) {
+ if (inittab[i].initfunc == NULL)
return -1;
else
return 1;
@@ -984,7 +1032,7 @@ create_builtin(PyThreadState *tstate, PyObject *name, PyObject *spec)
}
PyObject *modules = tstate->interp->modules;
- for (struct _inittab *p = PyImport_Inittab; p->name != NULL; p++) {
+ for (struct _inittab *p = _PyRuntime.imports.inittab; p->name != NULL; p++) {
if (_PyUnicode_EqualToASCIIString(name, p->name)) {
if (p->initfunc == NULL) {
/* Cannot re-init internal module ("sys" or "builtins") */
@@ -2592,6 +2640,10 @@ PyImport_ExtendInittab(struct _inittab *newtab)
size_t i, n;
int res = 0;
+ if (_PyRuntime.imports.inittab != NULL) {
+ Py_FatalError("PyImport_ExtendInittab() may be be called after Py_Initialize()");
+ }
+
/* Count the number of entries in both tables */
for (n = 0; newtab[n].name != NULL; n++)
;
@@ -2636,6 +2688,10 @@ PyImport_AppendInittab(const char *name, PyObject* (*initfunc)(void))
{
struct _inittab newtab[2];
+ if (_PyRuntime.imports.inittab != NULL) {
+ Py_FatalError("PyImport_AppendInittab() may be be called after Py_Initialize()");
+ }
+
memset(newtab, '\0', sizeof newtab);
newtab[0].name = name;
diff --git a/Python/pylifecycle.c b/Python/pylifecycle.c
index 39e54c11475b..44f844249b13 100644
--- a/Python/pylifecycle.c
+++ b/Python/pylifecycle.c
@@ -605,6 +605,11 @@ pycore_init_runtime(_PyRuntimeState *runtime,
return status;
}
+ status = _PyImport_Init();
+ if (_PyStatus_EXCEPTION(status)) {
+ return status;
+ }
+
status = _PyInterpreterState_Enable(runtime);
if (_PyStatus_EXCEPTION(status)) {
return status;
diff --git a/Python/sysmodule.c b/Python/sysmodule.c
index 5de684e7195b..1090b124feab 100644
--- a/Python/sysmodule.c
+++ b/Python/sysmodule.c
@@ -2252,8 +2252,9 @@ list_builtin_module_names(void)
if (list == NULL) {
return NULL;
}
- for (Py_ssize_t i = 0; PyImport_Inittab[i].name != NULL; i++) {
- PyObject *name = PyUnicode_FromString(PyImport_Inittab[i].name);
+ struct _inittab *inittab = _PyRuntime.imports.inittab;
+ for (Py_ssize_t i = 0; inittab[i].name != NULL; i++) {
+ PyObject *name = PyUnicode_FromString(inittab[i].name);
if (name == NULL) {
goto error;
}
diff --git a/Tools/c-analyzer/cpython/globals-to-fix.tsv b/Tools/c-analyzer/cpython/globals-to-fix.tsv
index 53d42b740100..ad4e0aebc6d1 100644
--- a/Tools/c-analyzer/cpython/globals-to-fix.tsv
+++ b/Tools/c-analyzer/cpython/globals-to-fix.tsv
@@ -392,8 +392,6 @@ Python/frozen.c - _PyImport_FrozenAliases -
Python/frozen.c - _PyImport_FrozenBootstrap -
Python/frozen.c - _PyImport_FrozenStdlib -
Python/frozen.c - _PyImport_FrozenTest -
-Python/import.c - inittab_copy -
-Python/import.c - PyImport_Inittab -
Python/preconfig.c - Py_FileSystemDefaultEncoding -
Python/preconfig.c - Py_HasFileSystemDefaultEncoding -
Python/preconfig.c - Py_FileSystemDefaultEncodeErrors -
diff --git a/Tools/c-analyzer/cpython/ignored.tsv b/Tools/c-analyzer/cpython/ignored.tsv
index 6be61c94d87a..e657fa77be01 100644
--- a/Tools/c-analyzer/cpython/ignored.tsv
+++ b/Tools/c-analyzer/cpython/ignored.tsv
@@ -4,6 +4,8 @@ filename funcname name reason
##################################
# mutable but known to be safe
+Python/import.c - inittab_copy -
+Python/import.c - PyImport_Inittab -
Python/pylifecycle.c - _PyRuntime -
# All uses of _PyArg_Parser are handled in c-analyzr/cpython/_analyzer.py.
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