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/*
* Copyright (C) 2015 The Android Open Source Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include "private/bionic_allocator.h"
#include <stdlib.h>
#include <sys/cdefs.h>
#include <unistd.h>
#include <atomic>
#include <async_safe/log.h>
static BionicAllocator g_bionic_allocator;
static std::atomic<pid_t> fallback_tid(0);
// Used by libdebuggerd_handler to switch allocators during a crash dump, in
// case the linker heap is corrupted. Do not use this function.
extern "C" bool __linker_enable_fallback_allocator() {
pid_t expected = 0;
return fallback_tid.compare_exchange_strong(expected, gettid());
}
extern "C" void __linker_disable_fallback_allocator() {
pid_t previous = fallback_tid.exchange(0);
if (previous == 0) {
async_safe_fatal("attempted to disable unused fallback allocator");
} else if (previous != gettid()) {
async_safe_fatal("attempted to disable fallback allocator in use by another thread (%d)",
previous);
}
}
static BionicAllocator& get_fallback_allocator() {
static BionicAllocator fallback_allocator;
return fallback_allocator;
}
static BionicAllocator& get_allocator() {
if (__predict_false(fallback_tid) && __predict_false(gettid() == fallback_tid)) {
return get_fallback_allocator();
}
return g_bionic_allocator;
}
void* malloc(size_t byte_count) {
return get_allocator().alloc(byte_count);
}
void* calloc(size_t item_count, size_t item_size) {
return get_allocator().alloc(item_count*item_size);
}
void* realloc(void* p, size_t byte_count) {
return get_allocator().realloc(p, byte_count);
}
void* reallocarray(void* p, size_t item_count, size_t item_size) {
size_t byte_count;
if (__builtin_mul_overflow(item_count, item_size, &byte_count)) {
errno = ENOMEM;
return nullptr;
}
return get_allocator().realloc(p, byte_count);
}
void free(void* ptr) {
get_allocator().free(ptr);
}