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// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.
#include "ijwhost.h"
#include "bootstrap_thunk_chunk.h"
#include "error_codes.h"
#include "trace.h"
#include "utils.h"
#include "corhdr.h"
#include <heapapi.h>
#include <new>
#include <mutex>
#ifdef _WIN64
#define COR_VTABLE_PTRSIZED COR_VTABLE_64BIT
#define COR_VTABLE_NOT_PTRSIZED COR_VTABLE_32BIT
#else
#define COR_VTABLE_PTRSIZED COR_VTABLE_32BIT
#define COR_VTABLE_NOT_PTRSIZED COR_VTABLE_64BIT
#endif
namespace
{
std::mutex g_thunkChunkLock{};
bootstrap_thunk_chunk* g_pVtableBootstrapThunkChunkList;
// We swallow the trace messages so we don't output to a stderr of a process that we do not own unless tracing is enabled.
void __cdecl swallow_trace(const pal::char_t* msg)
{
(void)msg;
}
}
HANDLE g_heapHandle;
bool patch_vtable_entries(PEDecoder& pe)
{
size_t numFixupRecords;
IMAGE_COR_VTABLEFIXUP* pFixupTable = pe.GetVTableFixups(&numFixupRecords);
if (numFixupRecords == 0)
{
// If we have no fixups, no need to allocate thunks.
return true;
}
size_t numThunks = 0;
for (size_t i = 0; i < numFixupRecords; ++i)
{
numThunks += pFixupTable[i].Count;
}
size_t chunkSize = sizeof(bootstrap_thunk_chunk) + sizeof(bootstrap_thunk) * numThunks;
void* pbChunk = HeapAlloc(g_heapHandle, 0, chunkSize);
if (pbChunk == nullptr)
{
return false;
}
bootstrap_thunk_chunk* chunk = new (pbChunk) bootstrap_thunk_chunk(numThunks, (pal::dll_t)pe.GetBase());
{
std::lock_guard<std::mutex> lock(g_thunkChunkLock);
chunk->SetNext(g_pVtableBootstrapThunkChunkList);
g_pVtableBootstrapThunkChunkList = chunk;
}
trace::setup();
error_writer_scope_t writer_scope(swallow_trace);
size_t currentThunk = 0;
for(size_t i = 0; i < numFixupRecords; ++i)
{
if (pFixupTable[i].Type & COR_VTABLE_PTRSIZED)
{
const BYTE** pointers = (const BYTE**)pe.GetRvaData(pFixupTable[i].RVA);
#ifdef _WIN64
DWORD oldProtect;
if(!VirtualProtect(pointers, (sizeof(BYTE*) * pFixupTable[i].Count), PAGE_READWRITE, &oldProtect))
{
trace::error(_X("Failed to change the vtfixup table from RO to R/W failed.\n"));
return false;
}
#endif
for (std::uint16_t method = 0; method < pFixupTable[i].Count; method++)
{
mdToken tok = (mdToken)(std::uintptr_t) pointers[method];
bootstrap_thunk* pThunk = chunk->GetThunk(currentThunk++);
pThunk->initialize((std::uintptr_t)&start_runtime_thunk_stub,
(pal::dll_t)pe.GetBase(),
tok,
(std::uintptr_t *)&pointers[method]);
pointers[method] = (BYTE*)pThunk->get_entrypoint();
}
#ifdef _WIN64
DWORD _;
if(!VirtualProtect(pointers, (sizeof(BYTE*) * pFixupTable[i].Count), oldProtect, &_))
{
trace::warning(_X("Failed to change the vtfixup table from R/W back to RO failed.\n"));
}
#endif
}
}
return true;
}
extern "C" std::uintptr_t __stdcall start_runtime_and_get_target_address(std::uintptr_t cookie)
{
trace::setup();
error_writer_scope_t writer_scope(swallow_trace);
bootstrap_thunk *pThunk = bootstrap_thunk::get_thunk_from_cookie(cookie);
load_in_memory_assembly_fn loadInMemoryAssembly;
pal::dll_t moduleHandle = pThunk->get_dll_handle();
pal::hresult_t status = get_load_in_memory_assembly_delegate(moduleHandle, &loadInMemoryAssembly);
if (status != StatusCode::Success)
{
// If we ignore the failure to patch bootstrap thunks we will come to this same
// function again, causing an infinite loop of "Failed to start the .NET runtime" errors.
// As we were taken here via an entry point with arbitrary signature,
// there's no way of returning the error code so we just throw it.
trace::error(_X("Failed to start the .NET runtime. Error code %d"), status);
#pragma warning (push)
#pragma warning (disable: 4297)
throw status;
#pragma warning (pop)
}
pal::string_t app_path;
if (!pal::get_module_path(moduleHandle, &app_path))
{
#pragma warning (push)
#pragma warning (disable: 4297)
throw StatusCode::LibHostCurExeFindFailure;
#pragma warning (pop)
}
loadInMemoryAssembly(moduleHandle, app_path.c_str());
std::uintptr_t thunkAddress = *(pThunk->get_slot_address());
return thunkAddress;
}
void release_bootstrap_thunks(PEDecoder& pe)
{
std::lock_guard<std::mutex> lock(g_thunkChunkLock);
// Clean up the VTable thunks if they exist.
for (bootstrap_thunk_chunk **ppCurChunk = &g_pVtableBootstrapThunkChunkList;
*ppCurChunk != NULL;
ppCurChunk = (*ppCurChunk)->GetNextPtr())
{
if ((*ppCurChunk)->get_dll_handle() == (pal::dll_t) pe.GetBase())
{
bootstrap_thunk_chunk *pDel = *ppCurChunk;
*ppCurChunk = (*ppCurChunk)->GetNext();
HeapFree(g_heapHandle, 0, pDel);
break;
}
}
}
bool are_thunks_installed_for_module(pal::dll_t instance)
{
std::lock_guard<std::mutex> lock{g_thunkChunkLock};
bootstrap_thunk_chunk* currentChunk = g_pVtableBootstrapThunkChunkList;
while (currentChunk != nullptr)
{
if (currentChunk->get_dll_handle() == instance)
{
return true;
}
currentChunk = currentChunk->GetNext();
}
return false;
}
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