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/*
* Copyright (C) 2012 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#pragma once
/**
* @file malloc.h
* @brief Heap memory allocation.
*
* [Debugging Native Memory Use](https://source.android.com/devices/tech/debug/native-memory)
* is the canonical source for documentation on Android's heap debugging
* features.
*/
#include <sys/cdefs.h>
#include <stddef.h>
#include <stdio.h>
__BEGIN_DECLS
#define __BIONIC_ALLOC_SIZE(...) __attribute__((__alloc_size__(__VA_ARGS__)))
/**
* [malloc(3)](http://man7.org/linux/man-pages/man3/malloc.3.html) allocates
* memory on the heap.
*
* Returns a pointer to the allocated memory on success and returns a null
* pointer and sets `errno` on failure.
*/
void* malloc(size_t __byte_count) __mallocfunc __BIONIC_ALLOC_SIZE(1) __wur;
/**
* [calloc(3)](http://man7.org/linux/man-pages/man3/calloc.3.html) allocates
* and clears memory on the heap.
*
* Returns a pointer to the allocated memory on success and returns a null
* pointer and sets `errno` on failure.
*/
void* calloc(size_t __item_count, size_t __item_size) __mallocfunc __BIONIC_ALLOC_SIZE(1,2) __wur;
/**
* [realloc(3)](http://man7.org/linux/man-pages/man3/realloc.3.html) resizes
* allocated memory on the heap.
*
* Returns a pointer (which may be different from `__ptr`) to the resized
* memory on success and returns a null pointer and sets `errno` on failure.
*/
void* realloc(void* __ptr, size_t __byte_count) __BIONIC_ALLOC_SIZE(2) __wur;
/**
* [reallocarray(3)](http://man7.org/linux/man-pages/man3/realloc.3.html) resizes
* allocated memory on the heap.
*
* Equivalent to `realloc(__ptr, __item_count * __item_size)` but fails if the
* multiplication overflows.
*
* Returns a pointer (which may be different from `__ptr`) to the resized
* memory on success and returns a null pointer and sets `errno` on failure.
*/
void* reallocarray(void* __ptr, size_t __item_count, size_t __item_size) __BIONIC_ALLOC_SIZE(2, 3) __wur __INTRODUCED_IN(29);
/**
* [free(3)](http://man7.org/linux/man-pages/man3/free.3.html) deallocates
* memory on the heap.
*/
void free(void* __ptr);
/**
* [memalign(3)](http://man7.org/linux/man-pages/man3/memalign.3.html) allocates
* memory on the heap with the required alignment.
*
* Returns a pointer to the allocated memory on success and returns a null
* pointer and sets `errno` on failure.
*
* See also posix_memalign().
*/
void* memalign(size_t __alignment, size_t __byte_count) __mallocfunc __BIONIC_ALLOC_SIZE(2) __wur;
/**
* [malloc_usable_size(3)](http://man7.org/linux/man-pages/man3/malloc_usable_size.3.html)
* returns the actual size of the given heap block.
*
* Available since API level 17.
*/
size_t malloc_usable_size(const void* __ptr) __INTRODUCED_IN(17);
#ifndef STRUCT_MALLINFO_DECLARED
#define STRUCT_MALLINFO_DECLARED 1
struct mallinfo {
/** Total number of non-mmapped bytes currently allocated from OS. */
size_t arena;
/** Number of free chunks. */
size_t ordblks;
/** (Unused.) */
size_t smblks;
/** (Unused.) */
size_t hblks;
/** Total number of bytes in mmapped regions. */
size_t hblkhd;
/** Maximum total allocated space; greater than total if trimming has occurred. */
size_t usmblks;
/** (Unused.) */
size_t fsmblks;
/** Total allocated space (normal or mmapped.) */
size_t uordblks;
/** Total free space. */
size_t fordblks;
/** Upper bound on number of bytes releasable by a trim operation. */
size_t keepcost;
};
#endif
/**
* [mallinfo(3)](http://man7.org/linux/man-pages/man3/mallinfo.3.html) returns
* information about the current state of the heap. Note that mallinfo() is
* inherently unreliable and consider using malloc_info() instead.
*/
struct mallinfo mallinfo(void);
/**
* [malloc_info(3)](http://man7.org/linux/man-pages/man3/malloc_info.3.html)
* writes information about the current state of the heap to the given stream.
*
* The XML structure for malloc_info() is as follows:
* ```
* <malloc version="jemalloc-1">
* <heap nr="INT">
* <allocated-large>INT</allocated-large>
* <allocated-huge>INT</allocated-huge>
* <allocated-bins>INT</allocated-bins>
* <bins-total>INT</bins-total>
* <bin nr="INT">
* <allocated>INT</allocated>
* <nmalloc>INT</nmalloc>
* <ndalloc>INT</ndalloc>
* </bin>
* <!-- more bins -->
* </heap>
* <!-- more heaps -->
* </malloc>
* ```
*
* Available since API level 23.
*/
int malloc_info(int __must_be_zero, FILE* __fp) __INTRODUCED_IN(23);
/**
* mallopt() option to set the decay time. Valid values are 0 and 1.
*
* Available since API level 27.
*/
#define M_DECAY_TIME (-100)
/**
* mallopt() option to immediately purge any memory not in use. This
* will release the memory back to the kernel. The value is ignored.
*
* Available since API level 28.
*/
#define M_PURGE (-101)
/**
* mallopt() option to tune the allocator's choice of memory tags to
* make it more likely that a certain class of memory errors will be
* detected. This is only relevant if MTE is enabled in this process
* and ignored otherwise. The value argument should be one of the
* M_MEMTAG_TUNING_* flags.
* NOTE: This is only available in scudo.
*
* Available since API level 31.
*/
#define M_MEMTAG_TUNING (-102)
/**
* When passed as a value of M_MEMTAG_TUNING mallopt() call, enables
* deterministic detection of linear buffer overflow and underflow
* bugs by assigning distinct tag values to adjacent allocations. This
* mode has a slightly reduced chance to detect use-after-free bugs
* because only half of the possible tag values are available for each
* memory location.
*
* Please keep in mind that MTE can not detect overflow within the
* same tag granule (16-byte aligned chunk), and can miss small
* overflows even in this mode. Such overflow can not be the cause of
* a memory corruption, because the memory within one granule is never
* used for multiple allocations.
*/
#define M_MEMTAG_TUNING_BUFFER_OVERFLOW 0
/**
* When passed as a value of M_MEMTAG_TUNING mallopt() call, enables
* independently randomized tags for uniform ~93% probability of
* detecting both spatial (buffer overflow) and temporal (use after
* free) bugs.
*/
#define M_MEMTAG_TUNING_UAF 1
/**
* mallopt() option for per-thread memory initialization tuning.
* The value argument should be one of:
* 1: Disable automatic heap initialization and, where possible, memory tagging,
* on this thread.
* 0: Normal behavior.
*
* Available since API level 31.
*/
#define M_THREAD_DISABLE_MEM_INIT (-103)
/**
* mallopt() option to set the maximum number of items in the secondary
* cache of the scudo allocator.
*
* Available since API level 31.
*/
#define M_CACHE_COUNT_MAX (-200)
/**
* mallopt() option to set the maximum size in bytes of a cacheable item in
* the secondary cache of the scudo allocator.
*
* Available since API level 31.
*/
#define M_CACHE_SIZE_MAX (-201)
/**
* mallopt() option to increase the maximum number of shared thread-specific
* data structures that can be created. This number cannot be decreased,
* only increased and only applies to the scudo allocator.
*
* Available since API level 31.
*/
#define M_TSDS_COUNT_MAX (-202)
/**
* mallopt() option to decide whether heap memory is zero-initialized on
* allocation across the whole process. May be called at any time, including
* when multiple threads are running. An argument of zero indicates memory
* should not be zero-initialized, any other value indicates to initialize heap
* memory to zero.
*
* Note that this memory mitigation is only implemented in scudo and therefore
* this will have no effect when using another allocator (such as jemalloc on
* Android Go devices).
*
* Available since API level 31.
*/
#define M_BIONIC_ZERO_INIT (-203)
/**
* mallopt() option to change the heap tagging state. May be called at any
* time, including when multiple threads are running.
* The value must be one of the M_HEAP_TAGGING_LEVEL_ constants.
* NOTE: This is only available in scudo.
*
* Available since API level 31.
*/
#define M_BIONIC_SET_HEAP_TAGGING_LEVEL (-204)
/**
* Constants for use with the M_BIONIC_SET_HEAP_TAGGING_LEVEL mallopt() option.
*/
enum HeapTaggingLevel {
/**
* Disable heap tagging and memory tag checks (if supported).
* Heap tagging may not be re-enabled after being disabled.
*/
M_HEAP_TAGGING_LEVEL_NONE = 0,
#define M_HEAP_TAGGING_LEVEL_NONE M_HEAP_TAGGING_LEVEL_NONE
/**
* Address-only tagging. Heap pointers have a non-zero tag in the
* most significant ("top") byte which is checked in free(). Memory
* accesses ignore the tag using arm64's Top Byte Ignore (TBI) feature.
*/
M_HEAP_TAGGING_LEVEL_TBI = 1,
#define M_HEAP_TAGGING_LEVEL_TBI M_HEAP_TAGGING_LEVEL_TBI
/**
* Enable heap tagging and asynchronous memory tag checks (if supported).
* Disable stack trace collection.
*/
M_HEAP_TAGGING_LEVEL_ASYNC = 2,
#define M_HEAP_TAGGING_LEVEL_ASYNC M_HEAP_TAGGING_LEVEL_ASYNC
/**
* Enable heap tagging and synchronous memory tag checks (if supported).
* Enable stack trace collection.
*/
M_HEAP_TAGGING_LEVEL_SYNC = 3,
#define M_HEAP_TAGGING_LEVEL_SYNC M_HEAP_TAGGING_LEVEL_SYNC
};
/**
* [mallopt(3)](http://man7.org/linux/man-pages/man3/mallopt.3.html) modifies
* heap behavior. Values of `__option` are the `M_` constants from this header.
*
* Returns 1 on success, 0 on error.
*
* Available since API level 26.
*/
int mallopt(int __option, int __value) __INTRODUCED_IN(26);
/**
* [__malloc_hook(3)](http://man7.org/linux/man-pages/man3/__malloc_hook.3.html)
* is called to implement malloc(). By default this points to the system's
* implementation.
*
* Available since API level 28.
*
* See also: [extra documentation](https://android.googlesource.com/platform/bionic/+/master/libc/malloc_hooks/README.md)
*/
extern void* (*volatile __malloc_hook)(size_t __byte_count, const void* __caller) __INTRODUCED_IN(28);
/**
* [__realloc_hook(3)](http://man7.org/linux/man-pages/man3/__realloc_hook.3.html)
* is called to implement realloc(). By default this points to the system's
* implementation.
*
* Available since API level 28.
*
* See also: [extra documentation](https://android.googlesource.com/platform/bionic/+/master/libc/malloc_hooks/README.md)
*/
extern void* (*volatile __realloc_hook)(void* __ptr, size_t __byte_count, const void* __caller) __INTRODUCED_IN(28);
/**
* [__free_hook(3)](http://man7.org/linux/man-pages/man3/__free_hook.3.html)
* is called to implement free(). By default this points to the system's
* implementation.
*
* Available since API level 28.
*
* See also: [extra documentation](https://android.googlesource.com/platform/bionic/+/master/libc/malloc_hooks/README.md)
*/
extern void (*volatile __free_hook)(void* __ptr, const void* __caller) __INTRODUCED_IN(28);
/**
* [__memalign_hook(3)](http://man7.org/linux/man-pages/man3/__memalign_hook.3.html)
* is called to implement memalign(). By default this points to the system's
* implementation.
*
* Available since API level 28.
*
* See also: [extra documentation](https://android.googlesource.com/platform/bionic/+/master/libc/malloc_hooks/README.md)
*/
extern void* (*volatile __memalign_hook)(size_t __alignment, size_t __byte_count, const void* __caller) __INTRODUCED_IN(28);
__END_DECLS