mirror of
https://github.com/topjohnwu/Magisk.git
synced 2024-11-25 02:55:33 +00:00
32 lines
881 B
C++
32 lines
881 B
C++
#include "memory.hpp"
|
|
|
|
namespace jni_hook {
|
|
|
|
// We know our minimum alignment is WORD size (size of pointer)
|
|
static constexpr size_t ALIGN = sizeof(long);
|
|
|
|
// 4MB is more than enough
|
|
static constexpr size_t CAPACITY = (1 << 22);
|
|
|
|
// No need to be thread safe as the initial mmap always happens on the main thread
|
|
static uint8_t *_area = nullptr;
|
|
|
|
static std::atomic<uint8_t *> _curr = nullptr;
|
|
|
|
void *memory_block::allocate(size_t sz) {
|
|
if (!_area) {
|
|
// Memory will not actually be allocated because physical pages are mapped in on-demand
|
|
_area = static_cast<uint8_t *>(xmmap(
|
|
nullptr, CAPACITY, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0));
|
|
_curr = _area;
|
|
}
|
|
return _curr.fetch_add(align_to(sz, ALIGN));
|
|
}
|
|
|
|
void memory_block::release() {
|
|
if (_area)
|
|
munmap(_area, CAPACITY);
|
|
}
|
|
|
|
} // namespace jni_hook
|