1 /* The PyMem_ family: low-level memory allocation interfaces. 2 See objimpl.h for the PyObject_ memory family. 3 */ 4 5 #ifndef Py_PYMEM_H 6 #define Py_PYMEM_H 7 8 #include "pyport.h" 9 10 #ifdef __cplusplus 11 extern "C" { 12 #endif 13 14 #ifndef Py_LIMITED_API 15 PyAPI_FUNC(void *) PyMem_RawMalloc(size_t size); 16 PyAPI_FUNC(void *) PyMem_RawCalloc(size_t nelem, size_t elsize); 17 PyAPI_FUNC(void *) PyMem_RawRealloc(void *ptr, size_t new_size); 18 PyAPI_FUNC(void) PyMem_RawFree(void *ptr); 19 20 /* Configure the Python memory allocators. Pass NULL to use default 21 allocators. */ 22 PyAPI_FUNC(int) _PyMem_SetupAllocators(const char *opt); 23 24 #ifdef WITH_PYMALLOC 25 PyAPI_FUNC(int) _PyMem_PymallocEnabled(void); 26 #endif 27 28 /* Identifier of an address space (domain) in tracemalloc */ 29 typedef unsigned int _PyTraceMalloc_domain_t; 30 31 /* Track an allocated memory block in the tracemalloc module. 32 Return 0 on success, return -1 on error (failed to allocate memory to store 33 the trace). 34 35 Return -2 if tracemalloc is disabled. 36 37 If memory block is already tracked, update the existing trace. */ 38 PyAPI_FUNC(int) _PyTraceMalloc_Track( 39 _PyTraceMalloc_domain_t domain, 40 uintptr_t ptr, 41 size_t size); 42 43 /* Untrack an allocated memory block in the tracemalloc module. 44 Do nothing if the block was not tracked. 45 46 Return -2 if tracemalloc is disabled, otherwise return 0. */ 47 PyAPI_FUNC(int) _PyTraceMalloc_Untrack( 48 _PyTraceMalloc_domain_t domain, 49 uintptr_t ptr); 50 51 /* Get the traceback where a memory block was allocated. 52 53 Return a tuple of (filename: str, lineno: int) tuples. 54 55 Return None if the tracemalloc module is disabled or if the memory block 56 is not tracked by tracemalloc. 57 58 Raise an exception and return NULL on error. */ 59 PyAPI_FUNC(PyObject*) _PyTraceMalloc_GetTraceback( 60 _PyTraceMalloc_domain_t domain, 61 uintptr_t ptr); 62 #endif /* !Py_LIMITED_API */ 63 64 65 /* BEWARE: 66 67 Each interface exports both functions and macros. Extension modules should 68 use the functions, to ensure binary compatibility across Python versions. 69 Because the Python implementation is free to change internal details, and 70 the macros may (or may not) expose details for speed, if you do use the 71 macros you must recompile your extensions with each Python release. 72 73 Never mix calls to PyMem_ with calls to the platform malloc/realloc/ 74 calloc/free. For example, on Windows different DLLs may end up using 75 different heaps, and if you use PyMem_Malloc you'll get the memory from the 76 heap used by the Python DLL; it could be a disaster if you free()'ed that 77 directly in your own extension. Using PyMem_Free instead ensures Python 78 can return the memory to the proper heap. As another example, in 79 PYMALLOC_DEBUG mode, Python wraps all calls to all PyMem_ and PyObject_ 80 memory functions in special debugging wrappers that add additional 81 debugging info to dynamic memory blocks. The system routines have no idea 82 what to do with that stuff, and the Python wrappers have no idea what to do 83 with raw blocks obtained directly by the system routines then. 84 85 The GIL must be held when using these APIs. 86 */ 87 88 /* 89 * Raw memory interface 90 * ==================== 91 */ 92 93 /* Functions 94 95 Functions supplying platform-independent semantics for malloc/realloc/ 96 free. These functions make sure that allocating 0 bytes returns a distinct 97 non-NULL pointer (whenever possible -- if we're flat out of memory, NULL 98 may be returned), even if the platform malloc and realloc don't. 99 Returned pointers must be checked for NULL explicitly. No action is 100 performed on failure (no exception is set, no warning is printed, etc). 101 */ 102 103 PyAPI_FUNC(void *) PyMem_Malloc(size_t size); 104 #if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 >= 0x03050000 105 PyAPI_FUNC(void *) PyMem_Calloc(size_t nelem, size_t elsize); 106 #endif 107 PyAPI_FUNC(void *) PyMem_Realloc(void *ptr, size_t new_size); 108 PyAPI_FUNC(void) PyMem_Free(void *ptr); 109 110 #ifndef Py_LIMITED_API 111 PyAPI_FUNC(char *) _PyMem_RawStrdup(const char *str); 112 PyAPI_FUNC(char *) _PyMem_Strdup(const char *str); 113 #endif 114 115 /* Macros. */ 116 117 /* PyMem_MALLOC(0) means malloc(1). Some systems would return NULL 118 for malloc(0), which would be treated as an error. Some platforms 119 would return a pointer with no memory behind it, which would break 120 pymalloc. To solve these problems, allocate an extra byte. */ 121 /* Returns NULL to indicate error if a negative size or size larger than 122 Py_ssize_t can represent is supplied. Helps prevents security holes. */ 123 #define PyMem_MALLOC(n) PyMem_Malloc(n) 124 #define PyMem_REALLOC(p, n) PyMem_Realloc(p, n) 125 #define PyMem_FREE(p) PyMem_Free(p) 126 127 /* 128 * Type-oriented memory interface 129 * ============================== 130 * 131 * Allocate memory for n objects of the given type. Returns a new pointer 132 * or NULL if the request was too large or memory allocation failed. Use 133 * these macros rather than doing the multiplication yourself so that proper 134 * overflow checking is always done. 135 */ 136 137 #define PyMem_New(type, n) \ 138 ( ((size_t)(n) > PY_SSIZE_T_MAX / sizeof(type)) ? NULL : \ 139 ( (type *) PyMem_Malloc((n) * sizeof(type)) ) ) 140 #define PyMem_NEW(type, n) \ 141 ( ((size_t)(n) > PY_SSIZE_T_MAX / sizeof(type)) ? NULL : \ 142 ( (type *) PyMem_MALLOC((n) * sizeof(type)) ) ) 143 144 /* 145 * The value of (p) is always clobbered by this macro regardless of success. 146 * The caller MUST check if (p) is NULL afterwards and deal with the memory 147 * error if so. This means the original value of (p) MUST be saved for the 148 * caller's memory error handler to not lose track of it. 149 */ 150 #define PyMem_Resize(p, type, n) \ 151 ( (p) = ((size_t)(n) > PY_SSIZE_T_MAX / sizeof(type)) ? NULL : \ 152 (type *) PyMem_Realloc((p), (n) * sizeof(type)) ) 153 #define PyMem_RESIZE(p, type, n) \ 154 ( (p) = ((size_t)(n) > PY_SSIZE_T_MAX / sizeof(type)) ? NULL : \ 155 (type *) PyMem_REALLOC((p), (n) * sizeof(type)) ) 156 157 /* PyMem{Del,DEL} are left over from ancient days, and shouldn't be used 158 * anymore. They're just confusing aliases for PyMem_{Free,FREE} now. 159 */ 160 #define PyMem_Del PyMem_Free 161 #define PyMem_DEL PyMem_FREE 162 163 #ifndef Py_LIMITED_API 164 typedef enum { 165 /* PyMem_RawMalloc(), PyMem_RawRealloc() and PyMem_RawFree() */ 166 PYMEM_DOMAIN_RAW, 167 168 /* PyMem_Malloc(), PyMem_Realloc() and PyMem_Free() */ 169 PYMEM_DOMAIN_MEM, 170 171 /* PyObject_Malloc(), PyObject_Realloc() and PyObject_Free() */ 172 PYMEM_DOMAIN_OBJ 173 } PyMemAllocatorDomain; 174 175 typedef struct { 176 /* user context passed as the first argument to the 4 functions */ 177 void *ctx; 178 179 /* allocate a memory block */ 180 void* (*malloc) (void *ctx, size_t size); 181 182 /* allocate a memory block initialized by zeros */ 183 void* (*calloc) (void *ctx, size_t nelem, size_t elsize); 184 185 /* allocate or resize a memory block */ 186 void* (*realloc) (void *ctx, void *ptr, size_t new_size); 187 188 /* release a memory block */ 189 void (*free) (void *ctx, void *ptr); 190 } PyMemAllocatorEx; 191 192 /* Get the memory block allocator of the specified domain. */ 193 PyAPI_FUNC(void) PyMem_GetAllocator(PyMemAllocatorDomain domain, 194 PyMemAllocatorEx *allocator); 195 196 /* Set the memory block allocator of the specified domain. 197 198 The new allocator must return a distinct non-NULL pointer when requesting 199 zero bytes. 200 201 For the PYMEM_DOMAIN_RAW domain, the allocator must be thread-safe: the GIL 202 is not held when the allocator is called. 203 204 If the new allocator is not a hook (don't call the previous allocator), the 205 PyMem_SetupDebugHooks() function must be called to reinstall the debug hooks 206 on top on the new allocator. */ 207 PyAPI_FUNC(void) PyMem_SetAllocator(PyMemAllocatorDomain domain, 208 PyMemAllocatorEx *allocator); 209 210 /* Setup hooks to detect bugs in the following Python memory allocator 211 functions: 212 213 - PyMem_RawMalloc(), PyMem_RawRealloc(), PyMem_RawFree() 214 - PyMem_Malloc(), PyMem_Realloc(), PyMem_Free() 215 - PyObject_Malloc(), PyObject_Realloc() and PyObject_Free() 216 217 Newly allocated memory is filled with the byte 0xCB, freed memory is filled 218 with the byte 0xDB. Additionnal checks: 219 220 - detect API violations, ex: PyObject_Free() called on a buffer allocated 221 by PyMem_Malloc() 222 - detect write before the start of the buffer (buffer underflow) 223 - detect write after the end of the buffer (buffer overflow) 224 225 The function does nothing if Python is not compiled is debug mode. */ 226 PyAPI_FUNC(void) PyMem_SetupDebugHooks(void); 227 #endif 228 229 #ifdef __cplusplus 230 } 231 #endif 232 233 #endif /* !Py_PYMEM_H */ 234
