diff options
Diffstat (limited to 'Include/internal')
| -rw-r--r-- | Include/internal/pycore_pymem.h | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/Include/internal/pycore_pymem.h b/Include/internal/pycore_pymem.h index 1e7da87..78d457d 100644 --- a/Include/internal/pycore_pymem.h +++ b/Include/internal/pycore_pymem.h @@ -155,6 +155,31 @@ PyAPI_FUNC(int) _PyMem_SetDefaultAllocator( PyMemAllocatorDomain domain, PyMemAllocatorEx *old_alloc); +/* Heuristic checking if a pointer value is newly allocated + (uninitialized) or newly freed. The pointer is not dereferenced, only the + pointer value is checked. + + The heuristic relies on the debug hooks on Python memory allocators which + fills newly allocated memory with CLEANBYTE (0xCB) and newly freed memory + with DEADBYTE (0xDB). Detect also "untouchable bytes" marked + with FORBIDDENBYTE (0xFB). */ +static inline int _PyMem_IsPtrFreed(void *ptr) +{ + uintptr_t value = (uintptr_t)ptr; +#if SIZEOF_VOID_P == 8 + return (value == (uintptr_t)0xCBCBCBCBCBCBCBCB + || value == (uintptr_t)0xDBDBDBDBDBDBDBDB + || value == (uintptr_t)0xFBFBFBFBFBFBFBFB + ); +#elif SIZEOF_VOID_P == 4 + return (value == (uintptr_t)0xCBCBCBCB + || value == (uintptr_t)0xDBDBDBDB + || value == (uintptr_t)0xFBFBFBFB); +#else +# error "unknown pointer size" +#endif +} + #ifdef __cplusplus } #endif |