mach-detours/tests/test_dylib_function.cpp

// Copyright (c) Lysann Tranvouez.  All rights reserved.

#include <catch2/catch_test_macros.hpp>

#include <mach_detours.h>

#include "lib_function.h"
static int (*realLibFunction)() = libFunction;

static int libFunctionDetourCounter = 0;
static int libFunctionDetour()
{
    libFunctionDetourCounter++;
    return 94;
}
static int libFunctionDetourCallingReal()
{
    libFunctionDetourCounter++;
    return realLibFunction() + 94;
}

TEST_CASE( "Attaching custom function in dylib installs detour", "[attach][dylib]" )
{
    libFunctionCounter = 0;
    libFunctionDetourCounter = 0;

    REQUIRE( realLibFunction == libFunction );
    REQUIRE( libFunction() == 42 );
    REQUIRE( libFunctionCounter == 1 );
    REQUIRE( libFunctionDetourCounter == 0 );

    REQUIRE( detour_transaction_begin() == err_none );

    SECTION( "attach + transaction_commit" )
    {
        REQUIRE( detour_attach(reinterpret_cast<detour_func_t*>(&realLibFunction), reinterpret_cast<detour_func_t>(libFunctionDetour)) == err_none );
        CHECK( detour_transaction_commit() == err_none );
    }
    SECTION( "attach_and_commit" )
    {
        CHECK( detour_attach_and_commit(reinterpret_cast<detour_func_t*>(&realLibFunction), reinterpret_cast<detour_func_t>(libFunctionDetour)) == err_none );
    }

    CHECK( realLibFunction != libFunction );
    CHECK( libFunctionCounter == 1 );
    CHECK( libFunctionDetourCounter == 0 );
    CHECK( libFunction() == 94 );
    CHECK( libFunctionCounter == 1 );
    CHECK( libFunctionDetourCounter == 1 );

    // clean up
    REQUIRE( detour_transaction_begin() == err_none );
    CHECK( detour_detach_and_commit(reinterpret_cast<detour_func_t*>(&realLibFunction), reinterpret_cast<detour_func_t>(libFunctionDetour)) == err_none );
}

TEST_CASE( "We can call real function using the reassigned trampoline pointer", "[attach][dylib]" )
{
    libFunctionCounter = 0;
    libFunctionDetourCounter = 0;

    REQUIRE( realLibFunction == libFunction );
    REQUIRE( libFunction() == 42 );
    REQUIRE( libFunctionCounter == 1 );
    REQUIRE( libFunctionDetourCounter == 0 );

    REQUIRE( detour_transaction_begin() == err_none );
    CHECK( detour_attach_and_commit(reinterpret_cast<detour_func_t*>(&realLibFunction), reinterpret_cast<detour_func_t>(libFunctionDetour)) == err_none );

    CHECK( realLibFunction != libFunction );
    CHECK( realLibFunction() == 42 );
    CHECK( libFunctionCounter == 2 );
    CHECK( libFunctionDetourCounter == 0 );

    // clean up
    REQUIRE( detour_transaction_begin() == err_none );
    CHECK( detour_detach_and_commit(reinterpret_cast<detour_func_t*>(&realLibFunction), reinterpret_cast<detour_func_t>(libFunctionDetour)) == err_none );
}

TEST_CASE( "Detour function can call real function", "[attach][dylib]" )
{
    libFunctionCounter = 0;
    libFunctionDetourCounter = 0;

    REQUIRE( realLibFunction == libFunction );
    REQUIRE( libFunction() == 42 );
    REQUIRE( libFunctionCounter == 1 );
    REQUIRE( libFunctionDetourCounter == 0 );

    REQUIRE( detour_transaction_begin() == err_none );
    CHECK( detour_attach_and_commit(reinterpret_cast<detour_func_t*>(&realLibFunction), reinterpret_cast<detour_func_t>(libFunctionDetourCallingReal)) == err_none );

    CHECK( realLibFunction != libFunction );
    CHECK( libFunctionCounter == 1 );
    CHECK( libFunctionDetourCounter == 0 );
    CHECK( libFunction() == 94 + 42 );
    CHECK( libFunctionCounter == 2 );
    CHECK( libFunctionDetourCounter == 1 );

    // clean up
    REQUIRE( detour_transaction_begin() == err_none );
    CHECK( detour_detach_and_commit(reinterpret_cast<detour_func_t*>(&realLibFunction), reinterpret_cast<detour_func_t>(libFunctionDetourCallingReal)) == err_none );
}

TEST_CASE( "Detaching custom function in dylib removes detour", "[detach][dylib]" )
{
    libFunctionCounter = 0;
    libFunctionDetourCounter = 0;

    REQUIRE( detour_transaction_begin() == err_none );
    REQUIRE( detour_attach_and_commit(reinterpret_cast<detour_func_t*>(&realLibFunction), reinterpret_cast<detour_func_t>(libFunctionDetour)) == err_none );
    REQUIRE( realLibFunction != libFunction );

    // this must be a separate transaction because detach works only if the trampoline is actually in place already (committed)
    REQUIRE( detour_transaction_begin() == err_none );

    SECTION( "detach + transaction_commit" )
    {
        REQUIRE( detour_detach(reinterpret_cast<detour_func_t*>(&realLibFunction), reinterpret_cast<detour_func_t>(libFunctionDetour)) == err_none );
        CHECK( detour_transaction_commit() == err_none );
    }
    SECTION( "detach_and_commit" )
    {
        CHECK( detour_detach_and_commit(reinterpret_cast<detour_func_t*>(&realLibFunction), reinterpret_cast<detour_func_t>(libFunctionDetour)) == err_none );
    }

    CHECK( realLibFunction == libFunction );
    CHECK( libFunctionCounter == 0 );
    CHECK( libFunctionDetourCounter == 0 );
    CHECK( libFunction() == 42 );
    CHECK( libFunctionCounter == 1 );
    CHECK( libFunctionDetourCounter == 0 );
}