FunctionPatcherModule/source/export.cpp

#include "export.h"
#include "PatchedFunctionData.h"
#include "function_patcher.h"
#include "utils/globals.h"
#include <ranges>
#include <vector>
#include <wums/exports.h>

FunctionPatcherStatus FPAddFunctionPatch(function_replacement_data_t *function_data, PatchedFunctionHandle *outHandle, bool *outHasBeenPatched) {
    if (function_data == nullptr) {
        DEBUG_FUNCTION_LINE_ERR("function_data was NULL");
        return FUNCTION_PATCHER_RESULT_INVALID_ARGUMENT;
    }
    if (function_data->VERSION != FUNCTION_REPLACEMENT_DATA_STRUCT_VERSION) {
        DEBUG_FUNCTION_LINE_ERR("Failed to patch function. struct version mismatch");
        return FUNCTION_PATCHER_RESULT_UNSUPPORTED_STRUCT_VERSION;
    }

    auto functionDataOpt = PatchedFunctionData::make_shared(gFunctionAddressProvider, function_data, gJumpHeapHandle);

    if (!functionDataOpt) {
        return FUNCTION_PATCHER_RESULT_UNKNOWN_ERROR;
    }

    auto &functionData = functionDataOpt.value();

    // PatchFunction calls OSFatal on fatal errors.
    // If this function returns false the target function was not patched
    // Usually this means the target RPL is not (yet) loaded.
    auto patchResult = PatchFunction(functionData);
    if (outHasBeenPatched) {
        *outHasBeenPatched = patchResult;
    }

    if (outHandle) {
        *outHandle = functionData->getHandle();
    }

    {
        std::lock_guard<std::mutex> lock(gPatchedFunctionsMutex);
        gPatchedFunctions.push_back(std::move(functionData));

        OSMemoryBarrier();
    }

    return FUNCTION_PATCHER_RESULT_SUCCESS;
}

bool FunctionPatcherPatchFunction(function_replacement_data_t *function_data, PatchedFunctionHandle *outHandle) {
    return FPAddFunctionPatch(function_data, outHandle, nullptr) == FUNCTION_PATCHER_RESULT_SUCCESS;
}

FunctionPatcherStatus FPRemoveFunctionPatch(PatchedFunctionHandle handle) {
    std::lock_guard<std::mutex> lock(gPatchedFunctionsMutex);
    std::vector<std::shared_ptr<PatchedFunctionData>> toBeTempRestored;
    bool found            = false;
    int32_t erasePosition = 0;
    std::shared_ptr<PatchedFunctionData> toRemoved;
    for (auto &cur : gPatchedFunctions) {
        if (cur->getHandle() == handle) {
            toRemoved = cur;
            found     = true;
            if (!cur->isPatched) {
                // Early return if the function is not patched.
                break;
            }
            continue;
        }
        // Check if something else patched the same function afterwards.
        if (found) {
            if (cur->realPhysicalFunctionAddress == toRemoved->realPhysicalFunctionAddress) {
                toBeTempRestored.push_back(cur);
            }
        } else {
            erasePosition++;
        }
    }
    if (!found) {
        DEBUG_FUNCTION_LINE_ERR("Failed to find PatchedFunctionData by handle %08X", handle);
        return FUNCTION_PATCHER_RESULT_PATCH_NOT_FOUND;
    }

    if (toRemoved->isPatched) {
        // Restore function patches that were done after the patch we actually want to restore.
        for (auto &cur : std::ranges::reverse_view(toBeTempRestored)) {
            RestoreFunction(cur);
        }

        // Restore the function we actually want to restore
        RestoreFunction(toRemoved);
    }

    gPatchedFunctions.erase(gPatchedFunctions.begin() + erasePosition);

    if (toRemoved->isPatched) {
        // Apply the other patches again
        for (auto &cur : toBeTempRestored) {
            PatchFunction(cur);
        }
    }

    OSMemoryBarrier();
    return FUNCTION_PATCHER_RESULT_SUCCESS;
}

bool FunctionPatcherRestoreFunction(PatchedFunctionHandle handle) {
    return FPRemoveFunctionPatch(handle) == FUNCTION_PATCHER_RESULT_SUCCESS;
}

FunctionPatcherStatus FPGetVersion(FunctionPatcherAPIVersion *outVersion) {
    if (outVersion == nullptr) {
        return FUNCTION_PATCHER_RESULT_INVALID_ARGUMENT;
    }
    *outVersion = 2;
    return FUNCTION_PATCHER_RESULT_SUCCESS;
}

FunctionPatcherStatus FPIsFunctionPatched(PatchedFunctionHandle handle, bool *outIsFunctionPatched) {
    if (outIsFunctionPatched == nullptr) {
        return FUNCTION_PATCHER_RESULT_INVALID_ARGUMENT;
    }
    std::lock_guard<std::mutex> lock(gPatchedFunctionsMutex);
    for (auto &cur : gPatchedFunctions) {
        if (cur->getHandle() == handle) {
            *outIsFunctionPatched = cur->isPatched;
            return FUNCTION_PATCHER_RESULT_SUCCESS;
        }
    }
    return FUNCTION_PATCHER_RESULT_PATCH_NOT_FOUND;
}

WUMS_EXPORT_FUNCTION(FPGetVersion);
WUMS_EXPORT_FUNCTION(FPAddFunctionPatch);
WUMS_EXPORT_FUNCTION(FPRemoveFunctionPatch);
WUMS_EXPORT_FUNCTION(FPIsFunctionPatched);