geode/loader/src/platform/mac/Core.cpp

#include "Core.hpp"
#include "../../core/Core.hpp"

#include <Geode/DefaultInclude.hpp>

#ifdef GEODE_IS_MACOS

    #include <mach/mach.h>
    #include <mach/mach_init.h> /* mach_task_self()     */
    #include <mach/mach_port.h>
    #include <mach/mach_vm.h> /* mach_vm_*            */
    #include <mach/task.h>
    #include <signal.h> /* sigaction            */
    #include <sys/ucontext.h> /* ucontext_t           */

using namespace geode::core::hook;
using namespace geode::core::impl;

namespace {
    void signalHandler(int signal, siginfo_t* signal_info, void* vcontext) {
        auto context = reinterpret_cast<ucontext_t*>(vcontext);

        auto current = reinterpret_cast<void*>(context->uc_mcontext->__ss.__rip);

        handleContext(vcontext, current);
    }
}

bool MacOSX::enableSingleStep(void* vcontext) {
    auto context = reinterpret_cast<ucontext_t*>(vcontext);
    context->uc_mcontext->__ss.__rflags |= ((unsigned long)0x100);
    return true;
}

bool MacOSX::disableSingleStep(void* vcontext) {
    auto context = reinterpret_cast<ucontext_t*>(vcontext);
    context->uc_mcontext->__ss.__rflags &= ~((unsigned long)0x100);
    return true;
}

void* MacOSX::allocateVM(size_t size) {
    mach_vm_address_t ret;

    kern_return_t status; // return status

    status = mach_vm_allocate(mach_task_self(), &ret, (mach_vm_size_t)size, VM_FLAGS_ANYWHERE);

    return (void*)ret;
}

std::vector<std::byte> MacOSX::jump(void* from, void* to) {
    constexpr size_t size = sizeof(int) + 1;
    std::vector<std::byte> ret(size);
    ret[0] = { 0xe9 };

    int offset = (int)((size_t)to - (size_t)from - size);
    // im too lazy
    ((int*)((size_t)ret.data() + 1))[0] = offset;

    return ret;
}

bool MacOSX::writeMemory(void* to, void* from, size_t size) {
    kern_return_t status; // return status

    mach_vm_size_t vmsize;
    mach_vm_address_t address = (mach_vm_address_t)to;
    vm_region_basic_info_data_t info;
    mach_msg_type_number_t info_count = VM_REGION_BASIC_INFO_COUNT;
    mach_port_t object;

    // std::cout << "get memory protection" << std::endl;
    // // get memory protection
    // status = mach_vm_region(mach_task_self(), &address, &vmsize, VM_REGION_BASIC_INFO,
    // (vm_region_info_t)&info, &info_count, &object); std::cout << status << std::endl; if (status
    // != KERN_SUCCESS) return false;

    // std::cout << "set to write protection" << std::endl;
    // set to write protection
    status = mach_vm_protect(
        mach_task_self(), (mach_vm_address_t)to, size, FALSE,
        VM_PROT_COPY | VM_PROT_EXECUTE | VM_PROT_WRITE | VM_PROT_READ
    );
    if (status != KERN_SUCCESS) return false;

    // std::cout << "write to memory" << std::endl;
    // write to memory
    status = mach_vm_write(
        mach_task_self(), (mach_vm_address_t)to, (vm_offset_t)from, (mach_msg_type_number_t)size
    );
    if (status != KERN_SUCCESS) return false;

    // std::cout << "revert to old protection" << std::endl;
    // // revert to old protection
    // status = mach_vm_protect(mach_task_self(), (mach_vm_address_t)to, size, FALSE,
    // info.protection); if (status != KERN_SUCCESS) return false;

    return status == KERN_SUCCESS;
}

bool MacOSX::initialize() {
    task_set_exception_ports(
        mach_task_self(), EXC_MASK_BAD_INSTRUCTION,
        MACH_PORT_NULL, // m_exception_port,
        EXCEPTION_DEFAULT, 0
    );
    // first reached here
    struct sigaction action = {};
    action.sa_sigaction = &signalHandler;
    action.sa_flags = SA_SIGINFO;

    return sigaction(SIGILL, &action, NULL) == 0 && sigaction(SIGTRAP, &action, NULL) == 0;
}

#endif