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