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Avoid memory hook being triggered twice for the same callback

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This commit is contained in:
Igor Pissolati
2026-01-08 16:55:39 -03:00
parent d5d73f42c9
commit d33ef2d93f
2 changed files with 9 additions and 7 deletions
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4
src/windows-emulator/emulator_utils.hpp
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@@ -408,8 +408,8 @@ inline std::u16string read_unicode_string(emulator& emu, const uint64_t uc_strin
return read_unicode_string(emu, emulator_object<UNICODE_STRING<EmulatorTraits<Emu64>>>{emu, uc_string});
}
/// Retrieves function arguments from registers or stack memory. This function assumes the caller has already allocated
/// stack space and that RSP currently points to the return address.
/// Retrieves function arguments from registers or stack memory. This function assumes the stack pointer currently points to the
/// return address.
inline uint64_t get_function_argument(x86_64_emulator& emu, const size_t index, const bool is_syscall = false)
{
bool use_32bit_stack = false;

12
src/windows-emulator/process_context.cpp
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@@ -454,14 +454,16 @@ void process_context::setup_callback_hook(windows_emulator& win_emu, memory_mana
uint64_t sentinel_addr = this->callback_sentinel_addr;
if (!sentinel_addr)
{
auto sentinel_obj = this->base_allocator.reserve_page_aligned<uint8_t>();
using sentinel_type = std::array<uint8_t, 2>;
constexpr sentinel_type sentinel_opcodes{0x90, 0xC3}; // NOP, RET
auto sentinel_obj = this->base_allocator.reserve_page_aligned<sentinel_type>();
sentinel_addr = sentinel_obj.value();
this->callback_sentinel_addr = sentinel_addr;
const uint8_t ret_opcode = 0xC3;
win_emu.emu().write_memory(sentinel_addr, &ret_opcode, 1);
win_emu.emu().write_memory(sentinel_addr, sentinel_opcodes.data(), sentinel_opcodes.size());
const auto sentinel_aligned_length = page_align_up(sentinel_addr + 1) - sentinel_addr;
const auto sentinel_aligned_length = page_align_up(sentinel_addr + sentinel_opcodes.size()) - sentinel_addr;
memory.protect_memory(sentinel_addr, static_cast<size_t>(sentinel_aligned_length), memory_permission::all);
}
@@ -492,7 +494,7 @@ void process_context::setup_callback_hook(windows_emulator& win_emu, memory_mana
win_emu.dispatcher.dispatch_completion(win_emu, frame.handler_id, guest_result);
uint64_t target_rip = emu.reg(x86_register::rip);
emu.reg(x86_register::rip, this->callback_sentinel_addr);
emu.reg(x86_register::rip, this->callback_sentinel_addr + 1);
const bool new_callback_dispatched = t->callback_stack.size() > callbacks_before;
if (!new_callback_dispatched)