#include "hacklib/Main.h"

#include "hacklib/MessageBox.h"

#include "hacklib/PageAllocator.h"

#include <cstring>

#include <dlfcn.h>

#include <pthread.h>

#include <thread>

static void FreeLibAndExitThread(void* hModule, int (*adr_dlclose)(void*), void (*adr_pthread_exit)(void*))

{

// This can not be executed from inside the module.

// Don't generate any code that uses relative addressing to the IP.

adr_dlclose(hModule);

adr_pthread_exit((void*)0);

}

void hl::StaticInitImpl::runMainThread()

{

std::thread th(&StaticInitImpl::mainThread, this);

th.detach();

}

void hl::StaticInitImpl::unloadSelf()

{

// Get own module handle by path name. The dlclose just restores the refcount.

auto modName = hl::GetCurrentModulePath();

auto hModule = dlopen(modName.c_str(), RTLD_NOW | RTLD_LOCAL);

dlclose(hModule);

/*

Linux does not have an equivalent to FreeLibraryAndExitThread, so a race between

dlclose and pthread_exit would exist and lead to crashes.

The following method of detaching leaks a page = 4KiB each time, but is 100% reliable.

Alternative: Start a thread on dlclose. => Too unreliable, even with priority adjustments.

Alternative: Let the injector do dlclose. => Signaling mechanism needed; injector might die or be killed.

*/

// Limit copy size by available memory region.

auto funcAddress = (uintptr_t)&FreeLibAndExitThread;

auto memRegion = hl::GetMemoryByAddress(funcAddress);

auto sizeLeftInRegion = memRegion.base + memRegion.size - funcAddress;

auto codeSizeToCopy = std::min(hl::GetPageSize(), sizeLeftInRegion);

hl::code_page_vector code(codeSizeToCopy);

memcpy(code.data(), (void*)&FreeLibAndExitThread, codeSizeToCopy);

decltype (&FreeLibAndExitThread)(code.data())(hModule, &dlclose, &pthread_exit);

}