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Revert changeset 6661a8154eb3: Issue #3329: Add new APIs to customize memory allocators 

The new API require more discussion.
This commit is contained in:
Victor Stinner 2013-06-15 03:37:01 +02:00
parent 05a647deed
commit 36f01ad9ac
6 changed files with 211 additions and 771 deletions
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121
Doc/c-api/memory.rst
View File

@ -84,46 +84,6 @@ the C library allocator as shown in the previous example, the allocated memory
for the I/O buffer escapes completely the Python memory manager.
Raw Memory Interface
====================
The following function are wrappers to system allocators: :c:func:`malloc`,
:c:func:`realloc`, :c:func:`free`. These functions are thread-safe, the
:term:`GIL <global interpreter lock>` does not need to be held to use these
functions.
The behaviour of requesting zero bytes is not defined: return *NULL* or a
distinct non-*NULL* pointer depending on the platform. Use
:c:func:`PyMem_Malloc` and :c:func:`PyMem_Realloc` to have a well defined
behaviour.
.. versionadded:: 3.4
.. c:function:: void* PyMem_RawMalloc(size_t n)
Allocates *n* bytes and returns a pointer of type :c:type:`void\*` to the
allocated memory, or *NULL* if the request fails. The memory
will not have been initialized in any way.
.. c:function:: void* PyMem_RawRealloc(void *p, size_t n)
Resizes the memory block pointed to by *p* to *n* bytes. The contents will
be unchanged to the minimum of the old and the new sizes. If *p* is *NULL*,
the call is equivalent to ``PyMem_RawMalloc(n)``. Unless *p* is *NULL*, it
must have been returned by a previous call to :c:func:`PyMem_RawMalloc` or
:c:func:`PyMem_RawRealloc`. If the request fails, :c:func:`PyMem_RawRealloc`
returns *NULL* and *p* remains a valid pointer to the previous memory area.
.. c:function:: void PyMem_RawFree(void *p)
Frees the memory block pointed to by *p*, which must have been returned by a
previous call to :c:func:`PyMem_RawMalloc` or :c:func:`PyMem_RawRealloc`.
Otherwise, or if ``PyMem_Free(p)`` has been called before, undefined
behavior occurs. If *p* is *NULL*, no operation is performed.
.. _memoryinterface:
Memory Interface
@ -131,12 +91,8 @@ Memory Interface
The following function sets, modeled after the ANSI C standard, but specifying
behavior when requesting zero bytes, are available for allocating and releasing
memory from the Python heap.
memory from the Python heap:
.. warning::
The :term:`GIL <global interpreter lock>` must be held when using these
functions.
.. c:function:: void* PyMem_Malloc(size_t n)
@ -199,81 +155,6 @@ versions and is therefore deprecated in extension modules.
:c:func:`PyMem_NEW`, :c:func:`PyMem_RESIZE`, :c:func:`PyMem_DEL`.
Customize Memory Allocators
===========================
.. versionadded:: 3.4
.. c:type:: PyMemAllocators
Structure used to describe memory allocator. This structure has
four fields:
+----------------------------------------------------------+-----------------+
| Field | Meaning |
+==========================================================+=================+
| ``void *ctx`` | user data |
+----------------------------------------------------------+-----------------+
| ``void* malloc(void *ctx, size_t size)`` | allocate memory |
+----------------------------------------------------------+-----------------+
| ``void* realloc(void *ctx, void *ptr, size_t new_size)`` | allocate memory |
| | or resize a |
| | memory block |
+----------------------------------------------------------+-----------------+
| ``void free(void *ctx, void *ptr)`` | release memory |
+----------------------------------------------------------+-----------------+
.. c:function:: void PyMem_GetRawAllocators(PyMemAllocators *allocators)
Get internal functions of :c:func:`PyMem_RawMalloc`, :c:func:`PyMem_RawRealloc`
and :c:func:`PyMem_RawFree`.
.. c:function:: void PyMem_SetRawAllocators(PyMemAllocators *allocators)
Set internal functions of :c:func:`PyMem_RawMalloc`, :c:func:`PyMem_RawRealloc`
and :c:func:`PyMem_RawFree`.
:c:func:`PyMem_SetupDebugHooks` should be called to reinstall debug hooks if
new functions do no call original functions anymore.
.. c:function:: void PyMem_GetAllocators(PyMemAllocators *allocators)
Get internal functions of :c:func:`PyMem_Malloc`, :c:func:`PyMem_Realloc`
and :c:func:`PyMem_Free`.
.. c:function:: void PyMem_SetAllocators(PyMemAllocators *allocators)
Set internal functions of :c:func:`PyMem_Malloc`, :c:func:`PyMem_Realloc`
and :c:func:`PyMem_Free`.
``malloc(ctx, 0)`` and ``realloc(ctx, ptr, 0)`` must not return *NULL*: it
would be treated as an error.
:c:func:`PyMem_SetupDebugHooks` should be called to reinstall debug hooks if
new functions do no call original functions anymore.
.. c:function:: void PyMem_SetupDebugHooks(void)
Setup hooks to detect bugs in the following Python memory allocator
functions:
- :c:func:`PyMem_RawMalloc`, :c:func:`PyMem_RawRealloc`,
:c:func:`PyMem_RawFree`
- :c:func:`PyMem_Malloc`, :c:func:`PyMem_Realloc`, :c:func:`PyMem_Free`
- :c:func:`PyObject_Malloc`, :c:func:`PyObject_Realloc`,
:c:func:`PyObject_Free`
Newly allocated memory is filled with the byte ``0xCB``, freed memory is
filled with the byte ``0xDB``. Additionnal checks:
- detect API violations, ex: :c:func:`PyObject_Free` called on a buffer
allocated by :c:func:`PyMem_Malloc`
- detect write before the start of the buffer (buffer underflow)
- detect write after the end of the buffer (buffer overflow)
The function does nothing if Python is not compiled is debug mode.
.. _memoryexamples:
Examples

71
Include/objimpl.h
View File

@ -94,9 +94,9 @@ PyObject_{New, NewVar, Del}.
the object gets initialized via PyObject_{Init, InitVar} after obtaining
the raw memory.
*/
PyAPI_FUNC(void *) PyObject_Malloc(size_t size);
PyAPI_FUNC(void *) PyObject_Realloc(void *ptr, size_t new_size);
PyAPI_FUNC(void) PyObject_Free(void *ptr);
PyAPI_FUNC(void *) PyObject_Malloc(size_t);
PyAPI_FUNC(void *) PyObject_Realloc(void *, size_t);
PyAPI_FUNC(void) PyObject_Free(void *);
/* This function returns the number of allocated memory blocks, regardless of size */
PyAPI_FUNC(Py_ssize_t) _Py_GetAllocatedBlocks(void);
@ -106,46 +106,41 @@ PyAPI_FUNC(Py_ssize_t) _Py_GetAllocatedBlocks(void);
#ifndef Py_LIMITED_API
PyAPI_FUNC(void) _PyObject_DebugMallocStats(FILE *out);
#endif /* #ifndef Py_LIMITED_API */
#endif
#ifdef PYMALLOC_DEBUG /* WITH_PYMALLOC && PYMALLOC_DEBUG */
PyAPI_FUNC(void *) _PyObject_DebugMalloc(size_t nbytes);
PyAPI_FUNC(void *) _PyObject_DebugRealloc(void *p, size_t nbytes);
PyAPI_FUNC(void) _PyObject_DebugFree(void *p);
PyAPI_FUNC(void) _PyObject_DebugDumpAddress(const void *p);
PyAPI_FUNC(void) _PyObject_DebugCheckAddress(const void *p);
PyAPI_FUNC(void *) _PyObject_DebugMallocApi(char api, size_t nbytes);
PyAPI_FUNC(void *) _PyObject_DebugReallocApi(char api, void *p, size_t nbytes);
PyAPI_FUNC(void) _PyObject_DebugFreeApi(char api, void *p);
PyAPI_FUNC(void) _PyObject_DebugCheckAddressApi(char api, const void *p);
PyAPI_FUNC(void *) _PyMem_DebugMalloc(size_t nbytes);
PyAPI_FUNC(void *) _PyMem_DebugRealloc(void *p, size_t nbytes);
PyAPI_FUNC(void) _PyMem_DebugFree(void *p);
#define PyObject_MALLOC _PyObject_DebugMalloc
#define PyObject_Malloc _PyObject_DebugMalloc
#define PyObject_REALLOC _PyObject_DebugRealloc
#define PyObject_Realloc _PyObject_DebugRealloc
#define PyObject_FREE _PyObject_DebugFree
#define PyObject_Free _PyObject_DebugFree
/* Macros */
#else /* WITH_PYMALLOC && ! PYMALLOC_DEBUG */
#define PyObject_MALLOC PyObject_Malloc
#define PyObject_REALLOC PyObject_Realloc
#define PyObject_FREE PyObject_Free
#endif
#else /* ! WITH_PYMALLOC */
#define PyObject_MALLOC PyMem_MALLOC
#define PyObject_REALLOC PyMem_REALLOC
#define PyObject_FREE PyMem_FREE
#endif /* WITH_PYMALLOC */
#define PyObject_Del PyObject_Free
#define PyObject_DEL PyObject_Free
/* Get internal functions of PyObject_Malloc(), PyObject_Realloc() and
PyObject_Free(). *ctx_p is an arbitrary user value. */
PyAPI_FUNC(void) PyObject_GetAllocators(PyMemAllocators *allocators);
/* Set internal functions of PyObject_Malloc(), PyObject_Realloc() and PyObject_Free().
ctx is an arbitrary user value.
malloc(ctx, 0) and realloc(ctx, ptr, 0) must not return NULL: it would be
treated as an error.
PyMem_SetupDebugHooks() should be called to reinstall debug hooks if new
functions do no call original functions anymore. */
PyAPI_FUNC(void) PyObject_SetAllocators(PyMemAllocators *allocators);
/* Get internal functions allocating and deallocating arenas for
PyObject_Malloc(), PyObject_Realloc() and PyObject_Free().
*ctx_p is an arbitrary user value. */
PyAPI_FUNC(void) _PyObject_GetArenaAllocators(
void **ctx_p,
void* (**malloc_p) (void *ctx, size_t size),
void (**free_p) (void *ctx, void *ptr, size_t size)
);
/* Get internal functions allocating and deallocating arenas for
PyObject_Malloc(), PyObject_Realloc() and PyObject_Free().
ctx is an arbitrary user value. */
PyAPI_FUNC(void) _PyObject_SetArenaAllocators(
void *ctx,
void* (*malloc) (void *ctx, size_t size),
void (*free) (void *ctx, void *ptr, size_t size)
);
#define PyObject_DEL PyObject_FREE
/*
* Generic object allocator interface

91
Include/pymem.h
View File

@ -11,40 +11,6 @@
extern "C" {
#endif
typedef struct {
/* user context passed as the first argument to the 3 functions */
void *ctx;
/* allocate memory */
void* (*malloc) (void *ctx, size_t size);
/* allocate memory or resize a memory buffer */
void* (*realloc) (void *ctx, void *ptr, size_t new_size);
/* release memory */
void (*free) (void *ctx, void *ptr);
} PyMemAllocators;
/* Raw memory allocators, system functions: malloc(), realloc(), free().
These functions are thread-safe, the GIL does not need to be held. */
/* Get internal functions of PyMem_RawMalloc(), PyMem_RawRealloc() and
PyMem_RawFree(). *ctx_p is an arbitrary user value. */
PyAPI_FUNC(void) PyMem_GetRawAllocators(PyMemAllocators *allocators);
/* Set internal functions of PyMem_RawMalloc(), PyMem_RawRealloc() and
PyMem_RawFree(). ctx is an arbitrary user value.
PyMem_SetupDebugHooks() should be called to reinstall debug hooks if new
functions do no call original functions anymore. */
PyAPI_FUNC(void) PyMem_SetRawAllocators(PyMemAllocators *allocators);
PyAPI_FUNC(void *) PyMem_RawMalloc(size_t size);
PyAPI_FUNC(void *) PyMem_RawRealloc(void *ptr, size_t new_size);
PyAPI_FUNC(void) PyMem_RawFree(void *ptr);
/* BEWARE:
Each interface exports both functions and macros. Extension modules should
@ -83,11 +49,21 @@ PyAPI_FUNC(void) PyMem_RawFree(void *ptr);
performed on failure (no exception is set, no warning is printed, etc).
*/
PyAPI_FUNC(void *) PyMem_Malloc(size_t size);
PyAPI_FUNC(void *) PyMem_Realloc(void *ptr, size_t new_size);
PyAPI_FUNC(void) PyMem_Free(void *ptr);
PyAPI_FUNC(void *) PyMem_Malloc(size_t);
PyAPI_FUNC(void *) PyMem_Realloc(void *, size_t);
PyAPI_FUNC(void) PyMem_Free(void *);
/* Starting from Python 1.6, the wrappers Py_{Malloc,Realloc,Free} are
no longer supported. They used to call PyErr_NoMemory() on failure. */
/* Macros. */
#ifdef PYMALLOC_DEBUG
/* Redirect all memory operations to Python's debugging allocator. */
#define PyMem_MALLOC _PyMem_DebugMalloc
#define PyMem_REALLOC _PyMem_DebugRealloc
#define PyMem_FREE _PyMem_DebugFree
#else /* ! PYMALLOC_DEBUG */
/* PyMem_MALLOC(0) means malloc(1). Some systems would return NULL
for malloc(0), which would be treated as an error. Some platforms
@ -95,9 +71,13 @@ PyAPI_FUNC(void) PyMem_Free(void *ptr);
pymalloc. To solve these problems, allocate an extra byte. */
/* Returns NULL to indicate error if a negative size or size larger than
Py_ssize_t can represent is supplied. Helps prevents security holes. */
#define PyMem_MALLOC(n) PyMem_Malloc(n)
#define PyMem_REALLOC(p, n) PyMem_Realloc(p, n)
#define PyMem_FREE(p) PyMem_Free(p)
#define PyMem_MALLOC(n) ((size_t)(n) > (size_t)PY_SSIZE_T_MAX ? NULL \
: malloc((n) ? (n) : 1))
#define PyMem_REALLOC(p, n) ((size_t)(n) > (size_t)PY_SSIZE_T_MAX ? NULL \
: realloc((p), (n) ? (n) : 1))
#define PyMem_FREE free
#endif /* PYMALLOC_DEBUG */
/*
* Type-oriented memory interface
@ -135,37 +115,6 @@ PyAPI_FUNC(void) PyMem_Free(void *ptr);
#define PyMem_Del PyMem_Free
#define PyMem_DEL PyMem_FREE
/* Get internal functions of PyMem_Malloc(), PyMem_Realloc()
and PyMem_Free() */
PyAPI_FUNC(void) PyMem_GetAllocators(PyMemAllocators *allocators);
/* Set internal functions of PyMem_Malloc(), PyMem_Realloc() and PyMem_Free().
malloc(ctx, 0) and realloc(ctx, ptr, 0) must not return NULL: it would be
treated as an error.
PyMem_SetupDebugHooks() should be called to reinstall debug hooks if new
functions do no call original functions anymore. */
PyAPI_FUNC(void) PyMem_SetAllocators(PyMemAllocators *allocators);
/* Setup hooks to detect bugs in the following Python memory allocator
functions:
- PyMem_RawMalloc(), PyMem_RawRealloc(), PyMem_RawFree()
- PyMem_Malloc(), PyMem_Realloc(), PyMem_Free()
- PyObject_Malloc(), PyObject_Realloc() and PyObject_Free()
Newly allocated memory is filled with the byte 0xCB, freed memory is filled
with the byte 0xDB. Additionnal checks:
- detect API violations, ex: PyObject_Free() called on a buffer allocated
by PyMem_Malloc()
- detect write before the start of the buffer (buffer underflow)
- detect write after the end of the buffer (buffer overflow)
The function does nothing if Python is not compiled is debug mode. */
PyAPI_FUNC(void) PyMem_SetupDebugHooks(void);
#ifdef __cplusplus
}
#endif

178
Modules/_testcapimodule.c
View File

@ -2511,176 +2511,6 @@ test_decref_doesnt_leak(PyObject *ob)
Py_RETURN_NONE;
}
static PyObject *
test_pymem_alloc0(PyObject *self)
{
void *ptr;
ptr = PyMem_Malloc(0);
if (ptr == NULL) {
PyErr_SetString(PyExc_RuntimeError, "PyMem_Malloc(0) returns NULL");
return NULL;
}
PyMem_Free(ptr);
ptr = PyObject_Malloc(0);
if (ptr == NULL) {
PyErr_SetString(PyExc_RuntimeError, "PyObject_Malloc(0) returns NULL");
return NULL;
}
PyObject_Free(ptr);
Py_RETURN_NONE;
}
typedef struct {
PyMemAllocators alloc;
size_t malloc_size;
void *realloc_ptr;
size_t realloc_new_size;
void *free_ptr;
} alloc_hook_t;
static void* hook_malloc (void* ctx, size_t size)
{
alloc_hook_t *hook = (alloc_hook_t *)ctx;
hook->malloc_size = size;
return hook->alloc.malloc(hook->alloc.ctx, size);
}
static void* hook_realloc (void* ctx, void* ptr, size_t new_size)
{
alloc_hook_t *hook = (alloc_hook_t *)ctx;
hook->realloc_ptr = ptr;
hook->realloc_new_size = new_size;
return hook->alloc.realloc(hook->alloc.ctx, ptr, new_size);
}
static void hook_free (void *ctx, void *ptr)
{
alloc_hook_t *hook = (alloc_hook_t *)ctx;
printf("HOOK\n");
hook->free_ptr = ptr;
hook->alloc.free(hook->alloc.ctx, ptr);
}
static PyObject *
test_setallocators(char api)
{
PyObject *res = NULL;
const char *error_msg;
alloc_hook_t hook;
PyMemAllocators alloc;
size_t size, size2;
void *ptr, *ptr2;
hook.malloc_size = 0;
hook.realloc_ptr = NULL;
hook.realloc_new_size = 0;
hook.free_ptr = NULL;
alloc.ctx = &hook;
alloc.malloc = &hook_malloc;
alloc.realloc = &hook_realloc;
alloc.free = &hook_free;
if (api == 'o') {
PyObject_GetAllocators(&hook.alloc);
PyObject_SetAllocators(&alloc);
}
else if (api == 'r') {
PyMem_GetRawAllocators(&hook.alloc);
PyMem_SetRawAllocators(&alloc);
}
else {
PyMem_GetAllocators(&hook.alloc);
PyMem_SetAllocators(&alloc);
}
size = 42;
if (api == 'o')
ptr = PyObject_Malloc(size);
else if (api == 'r')
ptr = PyMem_RawMalloc(size);
else
ptr = PyMem_Malloc(size);
if (ptr == NULL) {
error_msg = "malloc failed";
goto fail;
}
if (hook.malloc_size != size) {
error_msg = "malloc invalid size";
goto fail;
}
size2 = 200;
if (api == 'o')
ptr2 = PyObject_Realloc(ptr, size2);
else if (api == 'r')
ptr2 = PyMem_RawRealloc(ptr, size2);
else
ptr2 = PyMem_Realloc(ptr, size2);
if (ptr2 == NULL) {
error_msg = "realloc failed";
goto fail;
}
if (hook.realloc_ptr != ptr
|| hook.realloc_new_size != size2) {
error_msg = "realloc invalid parameters";
goto fail;
}
if (api == 'o')
PyObject_Free(ptr2);
else if (api == 'r')
PyMem_RawFree(ptr2);
else {
printf("PyMem_Free\n");
PyMem_Free(ptr2);
}
if (hook.free_ptr != ptr2) {
error_msg = "free invalid pointer";
goto fail;
}
Py_INCREF(Py_None);
res = Py_None;
goto finally;
fail:
PyErr_SetString(PyExc_RuntimeError, error_msg);
finally:
if (api == 'o')
PyObject_SetAllocators(&hook.alloc);
else if (api == 'r')
PyMem_SetRawAllocators(&hook.alloc);
else
PyMem_SetAllocators(&hook.alloc);
return res;
}
static PyObject *
test_pymem_setrawallocators(PyObject *self)
{
return test_setallocators('r');
}
static PyObject *
test_pymem_setallocators(PyObject *self)
{
return test_setallocators('m');
}
static PyObject *
test_pyobject_setallocators(PyObject *self)
{
return test_setallocators('o');
}
static PyMethodDef TestMethods[] = {
{"raise_exception", raise_exception, METH_VARARGS},
{"raise_memoryerror", (PyCFunction)raise_memoryerror, METH_NOARGS},
@ -2781,14 +2611,6 @@ static PyMethodDef TestMethods[] = {
{"pytime_object_to_time_t", test_pytime_object_to_time_t, METH_VARARGS},
{"pytime_object_to_timeval", test_pytime_object_to_timeval, METH_VARARGS},
{"pytime_object_to_timespec", test_pytime_object_to_timespec, METH_VARARGS},
{"test_pymem",
(PyCFunction)test_pymem_alloc0, METH_NOARGS},
{"test_pymem_alloc0",
(PyCFunction)test_pymem_setrawallocators, METH_NOARGS},
{"test_pymem_setallocators",
(PyCFunction)test_pymem_setallocators, METH_NOARGS},
{"test_pyobject_setallocators",
(PyCFunction)test_pyobject_setallocators, METH_NOARGS},
{NULL, NULL} /* sentinel */
};

20
Objects/object.c
View File

@ -1859,6 +1859,26 @@ PyTypeObject *_PyCapsule_hack = &PyCapsule_Type;
Py_ssize_t (*_Py_abstract_hack)(PyObject *) = PyObject_Size;
/* Python's malloc wrappers (see pymem.h) */
void *
PyMem_Malloc(size_t nbytes)
{
return PyMem_MALLOC(nbytes);
}
void *
PyMem_Realloc(void *p, size_t nbytes)
{
return PyMem_REALLOC(p, nbytes);
}
void
PyMem_Free(void *p)
{
PyMem_FREE(p);
}
void
_PyObject_DebugTypeStats(FILE *out)
{

499
Objects/obmalloc.c
View File

@ -1,327 +1,5 @@
#include "Python.h"
/* Python's malloc wrappers (see pymem.h) */
/* Forward declaration */
#ifdef PYMALLOC_DEBUG /* WITH_PYMALLOC && PYMALLOC_DEBUG */
static void* _PyMem_DebugMalloc(void *ctx, size_t size);
static void _PyMem_DebugFree(void *ctx, void *p);
static void* _PyMem_DebugRealloc(void *ctx, void *ptr, size_t size);
static void _PyObject_DebugDumpAddress(const void *p);
static void _PyMem_DebugCheckAddress(char api_id, const void *p);
#endif
#ifdef WITH_PYMALLOC
static void* _PyObject_Malloc(void *ctx, size_t size);
static void _PyObject_Free(void *ctx, void *p);
static void* _PyObject_Realloc(void *ctx, void *ptr, size_t size);
#endif
static void *
_PyMem_RawMalloc(void *ctx, size_t size)
{
return malloc(size);
}
static void *
_PyMem_RawRealloc(void *ctx, void *ptr, size_t size)
{
return realloc(ptr, size);
}
static void
_PyMem_RawFree(void *ctx, void *ptr)
{
return free(ptr);
}
static void *
_PyMem_Malloc(void *ctx, size_t size)
{
/* PyMem_Malloc(0) means malloc(1). Some systems would return NULL
for malloc(0), which would be treated as an error. Some platforms would
return a pointer with no memory behind it, which would break pymalloc.
To solve these problems, allocate an extra byte. */
if (size == 0)
size = 1;
return malloc(size);
}
static void *
_PyMem_Realloc(void *ctx, void *ptr, size_t size)
{
if (size == 0)
size = 1;
return realloc(ptr, size);
}
#ifdef ARENAS_USE_MMAP
static void *
_PyObject_ArenaMmap(void *ctx, size_t size)
{
void *ptr;
ptr = mmap(NULL, size, PROT_READ|PROT_WRITE,
MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
if (ptr == MAP_FAILED)
return NULL;
assert(ptr != NULL);
return ptr;
}
static void
_PyObject_ArenaMunmap(void *ctx, void *ptr, size_t size)
{
return munmap(ptr, size);
}
#else
static void *
_PyObject_ArenaMalloc(void *ctx, size_t size)
{
return malloc(size);
}
static void
_PyObject_ArenaFree(void *ctx, void *ptr, size_t size)
{
free(ptr);
}
#endif
#define PYRAW_FUNCS _PyMem_RawMalloc, _PyMem_RawRealloc, _PyMem_RawFree
#define PYMEM_FUNCS _PyMem_Malloc, _PyMem_Realloc, _PyMem_RawFree
#ifdef WITH_PYMALLOC
#define PYOBJECT_FUNCS _PyObject_Malloc, _PyObject_Realloc, _PyObject_Free
#else
#define PYOBJECT_FUNCS PYMEM_FUNCS
#endif
#ifdef PYMALLOC_DEBUG
typedef struct {
/* We tag each block with an API ID in order to tag API violations */
char api_id;
PyMemAllocators alloc;
} debug_alloc_api_t;
static struct {
debug_alloc_api_t raw;
debug_alloc_api_t mem;
debug_alloc_api_t obj;
} _PyMem_Debug = {
{'r', {NULL, PYRAW_FUNCS}},
{'m', {NULL, PYMEM_FUNCS}},
{'o', {NULL, PYOBJECT_FUNCS}}
};
#define PYDEBUG_FUNCS _PyMem_DebugMalloc, _PyMem_DebugRealloc, _PyMem_DebugFree
#endif
static PyMemAllocators _PyMem_Raw = {
#ifdef PYMALLOC_DEBUG
&_PyMem_Debug.raw, PYDEBUG_FUNCS
#else
NULL, PYMEM_FUNCS
#endif
};
static PyMemAllocators _PyMem = {
#ifdef PYMALLOC_DEBUG
&_PyMem_Debug.mem, PYDEBUG_FUNCS
#else
NULL, PYMEM_FUNCS
#endif
};
static PyMemAllocators _PyObject = {
#ifdef PYMALLOC_DEBUG
&_PyMem_Debug.obj, PYDEBUG_FUNCS
#else
NULL, PYOBJECT_FUNCS
#endif
};
#undef PYRAW_FUNCS
#undef PYMEM_FUNCS
#undef PYOBJECT_FUNCS
#undef PYDEBUG_FUNCS
static struct {
void *ctx;
void* (*malloc) (void*, size_t);
void (*free) (void*, void*, size_t);
} _PyObject_Arena = {NULL,
#ifdef ARENAS_USE_MMAP
_PyObject_ArenaMmap, _PyObject_ArenaMunmap
#else
_PyObject_ArenaMalloc, _PyObject_ArenaFree
#endif
};
void
PyMem_SetupDebugHooks(void)
{
#ifdef PYMALLOC_DEBUG
PyMemAllocators alloc;
alloc.malloc = _PyMem_DebugMalloc;
alloc.realloc = _PyMem_DebugRealloc;
alloc.free = _PyMem_DebugFree;
if (_PyMem_Raw.malloc != _PyMem_DebugMalloc) {
alloc.ctx = &_PyMem_Debug.raw;
PyMem_GetAllocators(&_PyMem_Debug.raw.alloc);
PyMem_SetAllocators(&alloc);
}
if (_PyMem.malloc != _PyMem_DebugMalloc) {
alloc.ctx = &_PyMem_Debug.mem;
PyMem_GetAllocators(&_PyMem_Debug.mem.alloc);
PyMem_SetAllocators(&alloc);
}
if (_PyObject.malloc != _PyMem_DebugMalloc) {
alloc.ctx = &_PyMem_Debug.obj;
PyObject_GetAllocators(&_PyMem_Debug.obj.alloc);
PyObject_SetAllocators(&alloc);
}
#endif
}
void
PyMem_GetRawAllocators(PyMemAllocators *allocators)
{
*allocators = _PyMem_Raw;
}
void
PyMem_SetRawAllocators(PyMemAllocators *allocators)
{
_PyMem_Raw = *allocators;
}
void
PyMem_GetAllocators(PyMemAllocators *allocators)
{
*allocators = _PyMem;
}
void
PyMem_SetAllocators(PyMemAllocators *allocators)
{
_PyMem = *allocators;
}
void
PyObject_GetAllocators(PyMemAllocators *allocators)
{
*allocators = _PyObject;
}
void
PyObject_SetAllocators(PyMemAllocators *allocators)
{
_PyObject = *allocators;
}
void
_PyObject_GetArenaAllocators(void **ctx_p,
void* (**malloc_p) (void *ctx, size_t size),
void (**free_p) (void *ctx, void *ptr, size_t size))
{
*malloc_p = _PyObject_Arena.malloc;
*free_p = _PyObject_Arena.free;
*ctx_p = _PyObject_Arena.ctx;
}
void
_PyObject_SetArenaAllocators(void *ctx,
void* (*malloc) (void *ctx, size_t size),
void (*free) (void *ctx, void *ptr, size_t size))
{
_PyObject_Arena.malloc = malloc;
_PyObject_Arena.free = free;
_PyObject_Arena.ctx = ctx;
}
void *
PyMem_RawMalloc(size_t size)
{
return _PyMem_Raw.malloc(_PyMem_Raw.ctx, size);
}
void*
PyMem_RawRealloc(void *ptr, size_t new_size)
{
return _PyMem_Raw.realloc(_PyMem_Raw.ctx, ptr, new_size);
}
void PyMem_RawFree(void *ptr)
{
_PyMem_Raw.free(_PyMem_Raw.ctx, ptr);
}
void *
PyMem_Malloc(size_t size)
{
/*
* Limit ourselves to PY_SSIZE_T_MAX bytes to prevent security holes.
* Most python internals blindly use a signed Py_ssize_t to track
* things without checking for overflows or negatives.
* As size_t is unsigned, checking for size < 0 is not required.
*/
if (size > (size_t)PY_SSIZE_T_MAX)
return NULL;
return _PyMem.malloc(_PyMem.ctx, size);
}
void *
PyMem_Realloc(void *ptr, size_t new_size)
{
if (new_size > (size_t)PY_SSIZE_T_MAX)
return NULL;
return _PyMem.realloc(_PyMem.ctx, ptr, new_size);
}
void
PyMem_Free(void *ptr)
{
_PyMem.free(_PyMem.ctx, ptr);
}
void *
PyObject_Malloc(size_t size)
{
/*
* Limit ourselves to PY_SSIZE_T_MAX bytes to prevent security holes.
* Most python internals blindly use a signed Py_ssize_t to track
* things without checking for overflows or negatives.
* As size_t is unsigned, checking for size < 0 is not required.
*/
if (size > (size_t)PY_SSIZE_T_MAX)
return NULL;
return _PyObject.malloc(_PyObject.ctx, size);
}
void *
PyObject_Realloc(void *ptr, size_t new_size)
{
if (new_size > (size_t)PY_SSIZE_T_MAX)
return NULL;
return _PyObject.realloc(_PyObject.ctx, ptr, new_size);
}
void
PyObject_Free(void *ptr)
{
_PyObject.free(_PyObject.ctx, ptr);
}
#ifdef WITH_PYMALLOC
#ifdef HAVE_MMAP
@ -867,6 +545,7 @@ new_arena(void)
struct arena_object* arenaobj;
uint excess; /* number of bytes above pool alignment */
void *address;
int err;
#ifdef PYMALLOC_DEBUG
if (Py_GETENV("PYTHONMALLOCSTATS"))
@ -888,12 +567,11 @@ new_arena(void)
return NULL; /* overflow */
#endif
nbytes = numarenas * sizeof(*arenas);
arenaobj = (struct arena_object *)PyMem_Realloc(arenas, nbytes);
arenaobj = (struct arena_object *)realloc(arenas, nbytes);
if (arenaobj == NULL)
return NULL;
arenas = arenaobj;
/* We might need to fix pointers that were copied. However,
* new_arena only gets called when all the pages in the
* previous arenas are full. Thus, there are *no* pointers
@ -920,8 +598,15 @@ new_arena(void)
arenaobj = unused_arena_objects;
unused_arena_objects = arenaobj->nextarena;
assert(arenaobj->address == 0);
address = _PyObject_Arena.malloc(_PyObject_Arena.ctx, ARENA_SIZE);
if (address == NULL) {
#ifdef ARENAS_USE_MMAP
address = mmap(NULL, ARENA_SIZE, PROT_READ|PROT_WRITE,
MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
err = (address == MAP_FAILED);
#else
address = malloc(ARENA_SIZE);
err = (address == 0);
#endif
if (err) {
/* The allocation failed: return NULL after putting the
* arenaobj back.
*/
@ -1084,8 +769,9 @@ int Py_ADDRESS_IN_RANGE(void *P, poolp pool) Py_NO_INLINE;
* Unless the optimizer reorders everything, being too smart...
*/
static void *
_PyObject_Malloc(void *ctx, size_t nbytes)
#undef PyObject_Malloc
void *
PyObject_Malloc(size_t nbytes)
{
block *bp;
poolp pool;
@ -1101,6 +787,17 @@ _PyObject_Malloc(void *ctx, size_t nbytes)
goto redirect;
#endif
/*
* Limit ourselves to PY_SSIZE_T_MAX bytes to prevent security holes.
* Most python internals blindly use a signed Py_ssize_t to track
* things without checking for overflows or negatives.
* As size_t is unsigned, checking for nbytes < 0 is not required.
*/
if (nbytes > PY_SSIZE_T_MAX) {
_Py_AllocatedBlocks--;
return NULL;
}
/*
* This implicitly redirects malloc(0).
*/
@ -1273,8 +970,10 @@ redirect:
* last chance to serve the request) or when the max memory limit
* has been reached.
*/
if (nbytes == 0)
nbytes = 1;
{
void *result = PyMem_Malloc(nbytes);
void *result = malloc(nbytes);
if (!result)
_Py_AllocatedBlocks--;
return result;
@ -1283,8 +982,9 @@ redirect:
/* free */
static void
_PyObject_Free(void *ctx, void *p)
#undef PyObject_Free
void
PyObject_Free(void *p)
{
poolp pool;
block *lastfree;
@ -1393,8 +1093,11 @@ _PyObject_Free(void *ctx, void *p)
unused_arena_objects = ao;
/* Free the entire arena. */
_PyObject_Arena.free(_PyObject_Arena.ctx,
(void *)ao->address, ARENA_SIZE);
#ifdef ARENAS_USE_MMAP
munmap((void *)ao->address, ARENA_SIZE);
#else
free((void *)ao->address);
#endif
ao->address = 0; /* mark unassociated */
--narenas_currently_allocated;
@ -1503,7 +1206,7 @@ _PyObject_Free(void *ctx, void *p)
redirect:
#endif
/* We didn't allocate this address. */
PyMem_Free(p);
free(p);
}
/* realloc. If p is NULL, this acts like malloc(nbytes). Else if nbytes==0,
@ -1511,8 +1214,9 @@ redirect:
* return a non-NULL result.
*/
static void *
_PyObject_Realloc(void *ctx, void *p, size_t nbytes)
#undef PyObject_Realloc
void *
PyObject_Realloc(void *p, size_t nbytes)
{
void *bp;
poolp pool;
@ -1522,7 +1226,16 @@ _PyObject_Realloc(void *ctx, void *p, size_t nbytes)
#endif
if (p == NULL)
return _PyObject_Malloc(ctx, nbytes);
return PyObject_Malloc(nbytes);
/*
* Limit ourselves to PY_SSIZE_T_MAX bytes to prevent security holes.
* Most python internals blindly use a signed Py_ssize_t to track
* things without checking for overflows or negatives.
* As size_t is unsigned, checking for nbytes < 0 is not required.
*/
if (nbytes > PY_SSIZE_T_MAX)
return NULL;
#ifdef WITH_VALGRIND
/* Treat running_on_valgrind == -1 the same as 0 */
@ -1550,10 +1263,10 @@ _PyObject_Realloc(void *ctx, void *p, size_t nbytes)
}
size = nbytes;
}
bp = _PyObject_Malloc(ctx, nbytes);
bp = PyObject_Malloc(nbytes);
if (bp != NULL) {
memcpy(bp, p, size);
_PyObject_Free(ctx, p);
PyObject_Free(p);
}
return bp;
}
@ -1571,14 +1284,14 @@ _PyObject_Realloc(void *ctx, void *p, size_t nbytes)
* at p. Instead we punt: let C continue to manage this block.
*/
if (nbytes)
return PyMem_Realloc(p, nbytes);
return realloc(p, nbytes);
/* C doesn't define the result of realloc(p, 0) (it may or may not
* return NULL then), but Python's docs promise that nbytes==0 never
* returns NULL. We don't pass 0 to realloc(), to avoid that endcase
* to begin with. Even then, we can't be sure that realloc() won't
* return NULL.
*/
bp = PyMem_Realloc(p, 1);
bp = realloc(p, 1);
return bp ? bp : p;
}
@ -1588,6 +1301,24 @@ _PyObject_Realloc(void *ctx, void *p, size_t nbytes)
/* pymalloc not enabled: Redirect the entry points to malloc. These will
* only be used by extensions that are compiled with pymalloc enabled. */
void *
PyObject_Malloc(size_t n)
{
return PyMem_MALLOC(n);
}
void *
PyObject_Realloc(void *p, size_t n)
{
return PyMem_REALLOC(p, n);
}
void
PyObject_Free(void *p)
{
PyMem_FREE(p);
}
Py_ssize_t
_Py_GetAllocatedBlocks(void)
{
@ -1613,6 +1344,10 @@ _Py_GetAllocatedBlocks(void)
#define DEADBYTE 0xDB /* dead (newly freed) memory */
#define FORBIDDENBYTE 0xFB /* untouchable bytes at each end of a block */
/* We tag each block with an API ID in order to tag API violations */
#define _PYMALLOC_MEM_ID 'm' /* the PyMem_Malloc() API */
#define _PYMALLOC_OBJ_ID 'o' /* The PyObject_Malloc() API */
static size_t serialno = 0; /* incremented on each debug {m,re}alloc */
/* serialno is always incremented via calling this routine. The point is
@ -1695,18 +1430,58 @@ p[2*S: 2*S+n]
p[2*S+n: 2*S+n+S]
Copies of FORBIDDENBYTE. Used to catch over- writes and reads.
p[2*S+n+S: 2*S+n+2*S]
A serial number, incremented by 1 on each call to _PyMem_DebugMalloc
and _PyMem_DebugRealloc.
A serial number, incremented by 1 on each call to _PyObject_DebugMalloc
and _PyObject_DebugRealloc.
This is a big-endian size_t.
If "bad memory" is detected later, the serial number gives an
excellent way to set a breakpoint on the next run, to capture the
instant at which this block was passed out.
*/
static void *
_PyMem_DebugMalloc(void *ctx, size_t nbytes)
/* debug replacements for the PyMem_* memory API */
void *
_PyMem_DebugMalloc(size_t nbytes)
{
return _PyObject_DebugMallocApi(_PYMALLOC_MEM_ID, nbytes);
}
void *
_PyMem_DebugRealloc(void *p, size_t nbytes)
{
return _PyObject_DebugReallocApi(_PYMALLOC_MEM_ID, p, nbytes);
}
void
_PyMem_DebugFree(void *p)
{
_PyObject_DebugFreeApi(_PYMALLOC_MEM_ID, p);
}
/* debug replacements for the PyObject_* memory API */
void *
_PyObject_DebugMalloc(size_t nbytes)
{
return _PyObject_DebugMallocApi(_PYMALLOC_OBJ_ID, nbytes);
}
void *
_PyObject_DebugRealloc(void *p, size_t nbytes)
{
return _PyObject_DebugReallocApi(_PYMALLOC_OBJ_ID, p, nbytes);
}
void
_PyObject_DebugFree(void *p)
{
_PyObject_DebugFreeApi(_PYMALLOC_OBJ_ID, p);
}
void
_PyObject_DebugCheckAddress(const void *p)
{
_PyObject_DebugCheckAddressApi(_PYMALLOC_OBJ_ID, p);
}
/* generic debug memory api, with an "id" to identify the API in use */
void *
_PyObject_DebugMallocApi(char id, size_t nbytes)
{
debug_alloc_api_t *api = (debug_alloc_api_t *)ctx;
uchar *p; /* base address of malloc'ed block */
uchar *tail; /* p + 2*SST + nbytes == pointer to tail pad bytes */
size_t total; /* nbytes + 4*SST */
@ -1717,13 +1492,13 @@ _PyMem_DebugMalloc(void *ctx, size_t nbytes)
/* overflow: can't represent total as a size_t */
return NULL;
p = (uchar *)api->alloc.malloc(api->alloc.ctx, total);
p = (uchar *)PyObject_Malloc(total);
if (p == NULL)
return NULL;
/* at p, write size (SST bytes), id (1 byte), pad (SST-1 bytes) */
write_size_t(p, nbytes);
p[SST] = (uchar)api->api_id;
p[SST] = (uchar)id;
memset(p + SST + 1 , FORBIDDENBYTE, SST-1);
if (nbytes > 0)
@ -1742,27 +1517,25 @@ _PyMem_DebugMalloc(void *ctx, size_t nbytes)
Then fills the original bytes with DEADBYTE.
Then calls the underlying free.
*/
static void
_PyMem_DebugFree(void *ctx, void *p)
void
_PyObject_DebugFreeApi(char api, void *p)
{
debug_alloc_api_t *api = (debug_alloc_api_t *)ctx;
uchar *q = (uchar *)p - 2*SST; /* address returned from malloc */
size_t nbytes;
if (p == NULL)
return;
_PyMem_DebugCheckAddress(api->api_id, p);
_PyObject_DebugCheckAddressApi(api, p);
nbytes = read_size_t(q);
nbytes += 4*SST;
if (nbytes > 0)
memset(q, DEADBYTE, nbytes);
api->alloc.free(api->alloc.ctx, q);
PyObject_Free(q);
}
static void *
_PyMem_DebugRealloc(void *ctx, void *p, size_t nbytes)
void *
_PyObject_DebugReallocApi(char api, void *p, size_t nbytes)
{
debug_alloc_api_t *api = (debug_alloc_api_t *)ctx;
uchar *q = (uchar *)p;
uchar *tail;
size_t total; /* nbytes + 4*SST */
@ -1770,9 +1543,9 @@ _PyMem_DebugRealloc(void *ctx, void *p, size_t nbytes)
int i;
if (p == NULL)
return _PyMem_DebugMalloc(ctx, nbytes);
return _PyObject_DebugMallocApi(api, nbytes);
_PyMem_DebugCheckAddress(api->api_id, p);
_PyObject_DebugCheckAddressApi(api, p);
bumpserialno();
original_nbytes = read_size_t(q - 2*SST);
total = nbytes + 4*SST;
@ -1789,12 +1562,12 @@ _PyMem_DebugRealloc(void *ctx, void *p, size_t nbytes)
* case we didn't get the chance to mark the old memory with DEADBYTE,
* but we live with that.
*/
q = (uchar *)api->alloc.realloc(api->alloc.ctx, q - 2*SST, total);
q = (uchar *)PyObject_Realloc(q - 2*SST, total);
if (q == NULL)
return NULL;
write_size_t(q, nbytes);
assert(q[SST] == (uchar)api->api_id);
assert(q[SST] == (uchar)api);
for (i = 1; i < SST; ++i)
assert(q[SST + i] == FORBIDDENBYTE);
q += 2*SST;
@ -1816,8 +1589,8 @@ _PyMem_DebugRealloc(void *ctx, void *p, size_t nbytes)
* and call Py_FatalError to kill the program.
* The API id, is also checked.
*/
static void
_PyMem_DebugCheckAddress(char api, const void *p)
void
_PyObject_DebugCheckAddressApi(char api, const void *p)
{
const uchar *q = (const uchar *)p;
char msgbuf[64];
@ -1869,7 +1642,7 @@ error:
}
/* Display info to stderr about the memory block at p. */
static void
void
_PyObject_DebugDumpAddress(const void *p)
{
const uchar *q = (const uchar *)p;