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ucrtFreadWorkaround.cpp
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ucrtFreadWorkaround.cpp
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// Copyright 2014 Dolphin Emulator Project
// Licensed under GPLv2+
// Refer to the license.txt file included.
#if defined(_WIN32)
#include "CommonTypes.h"
#include <Windows.h>
struct PatchInfo {
const wchar_t *module_name;
u32 checksum;
u32 rva;
u32 length;
} static const s_patches[] = {
// 10.0.10240.16384 (th1.150709-1700)
{ L"ucrtbase.dll", 0xF61ED, 0x6AE7B, 5 },
// 10.0.10240.16390 (th1_st1.150714-1601)
{ L"ucrtbase.dll", 0xF5ED9, 0x6AE7B, 5 },
// 10.0.10137.0 (th1.150602-2238)
{ L"ucrtbase.dll", 0xF8B5E, 0x63ED6, 2 },
// 10.0.10150.0 (th1.150616-1659)
{ L"ucrtbased.dll", 0x1C1915 , 0x91905, 5 },
};
bool ApplyPatch(const PatchInfo &patch) {
auto module = GetModuleHandleW(patch.module_name);
if (module == nullptr)
{
return false;
}
auto ucrtbase_pe = (PIMAGE_NT_HEADERS)((uintptr_t)module + ((PIMAGE_DOS_HEADER)module)->e_lfanew);
if (ucrtbase_pe->OptionalHeader.CheckSum != patch.checksum) {
return false;
}
void *patch_addr = (void *)((uintptr_t)module + patch.rva);
size_t patch_size = patch.length;
DWORD old_protect;
if (!VirtualProtect(patch_addr, patch_size, PAGE_EXECUTE_READWRITE, &old_protect))
{
return false;
}
memset(patch_addr, 0x90, patch_size);
VirtualProtect(patch_addr, patch_size, old_protect, &old_protect);
FlushInstructionCache(GetCurrentProcess(), patch_addr, patch_size);
return true;
}
int __cdecl EnableucrtFreadWorkaround()
{
// This patches ucrtbase such that fseek will always
// synchronize the file object's internal buffer.
bool applied_at_least_one = false;
for (const auto &patch : s_patches) {
if (ApplyPatch(patch)) {
applied_at_least_one = true;
}
}
/* For forward compat, do not fail if patches don't apply (e.g. version mismatch)
if (!applied_at_least_one) {
std::abort();
}
//*/
return 0;
}
// Create a segment which is recognized by the linker to be part of the CRT
// initialization. XI* = C startup, XC* = C++ startup. "A" placement is reserved
// for system use. Thus, the earliest we can get is XIB (C startup is before
// C++).
#pragma section(".CRT$XIB", read)
// Place a symbol in the special segment, make it have C linkage so that
// referencing it doesn't require ugly decorated names.
// Use /include:EnableucrtFreadWorkaround linker flag to enable this.
extern "C" {
__declspec(allocate(".CRT$XIB"))
decltype(&EnableucrtFreadWorkaround) ucrtFreadWorkaround = EnableucrtFreadWorkaround;
};
#endif