init.cpp

// Copyright (c) Microsoft Corporation.
// Licensed under the MIT license.

#include"precomp.h"

#include"init.hpp"
#include"resource.h"

#pragma hdrstop

// Routine Description:
// - Ensures the SxS initialization for the process.
voidInitSideBySide()
{
// Account for the fact that sidebyside stuff happens in CreateProcess
// but conhost is run with RtlCreateUserProcess.

// If conhost is at some future date
// launched with CreateProcess or SideBySide support moved
// into the kernel and SideBySide setup moved to textmode, at which
// time this code block will not be needed.

// Until then, this code block is needed when activated as the default console in the OS by the loader.
// If the console is changed to be invoked a different way (for example if we add a main method that takes
// a parameter to a client application instead), then this code would be unnecessary but not likely harmful.

// Having SxS not initialized is a problem when 3rd party IMEs attempt to inject into the process and then
// make references to DLLs in the system that are in the SxS cache (ex. a 3rd party IME is loaded and asks for
// comctl32.dll. The load will fail if SxS wasn't initialized.) This was bug# WIN7:681280.

 ACTCTXW actctx{};
 actctx.cbSize = sizeof(actctx);
// We set ACTCTX_FLAG_HMODULE_VALID, but leave hModule as nullptr.
// A nullptr HMODULE refers to the current process/executable.
 actctx.lpResourceName = MAKEINTRESOURCE(IDR_SYSTEM_MANIFEST);
 actctx.dwFlags = ACTCTX_FLAG_RESOURCE_NAME_VALID | ACTCTX_FLAG_SET_PROCESS_DEFAULT | ACTCTX_FLAG_HMODULE_VALID;

constauto hActCtx = CreateActCtxW(&actctx);

// The error value is INVALID_HANDLE_VALUE.
// ACTCTX_FLAG_SET_PROCESS_DEFAULT has nothing to return upon success, so it returns nullptr.
// There is nothing to cleanup upon ACTCTX_FLAG_SET_PROCESS_DEFAULT success, the data
// is referenced in the PEB, and lasts till process shutdown.
if (hActCtx == INVALID_HANDLE_VALUE)
 {
constauto error = GetLastError();

// OpenConsole ships with a single manifest at ID 1, while conhost ships with 2 at ID 1
// and IDR_SYSTEM_MANIFEST. If we call CreateActCtxW() with IDR_SYSTEM_MANIFEST inside
// OpenConsole anyways, nothing happens and we get ERROR_SXS_PROCESS_DEFAULT_ALREADY_SET.
if (ERROR_SXS_PROCESS_DEFAULT_ALREADY_SET != error)
 {
LOG_WIN32_MSG(error, "InitSideBySide failed create an activation context.");
 }
 }
}

// Routine Description:
// - Sets the program files environment variables for the process, if missing.
voidInitEnvironmentVariables()
{
struct
 {
 LPCWSTR szRegValue;
 LPCWSTR szVariable;
 } EnvProgFiles[] = {
 { L"ProgramFilesDir", L"ProgramFiles" },
 { L"CommonFilesDir", L"CommonProgramFiles" },
#if BUILD_WOW64_ENABLED
 { L"ProgramFilesDir (x86)", L"ProgramFiles(x86)" },
 { L"CommonFilesDir (x86)", L"CommonProgramFiles(x86)" },
 { L"ProgramW6432Dir", L"ProgramW6432" },
 { L"CommonW6432Dir", L"CommonProgramW6432" }
#endif
 };

 WCHAR wchValue[MAX_PATH];
for (UINT i = 0; i < ARRAYSIZE(EnvProgFiles); i++)
 {
if (!GetEnvironmentVariable(EnvProgFiles[i].szVariable, nullptr, 0))
 {
 DWORD dwMaxBufferSize = sizeof(wchValue);
if (RegGetValue(HKEY_LOCAL_MACHINE,
L"Software\\Microsoft\\Windows\\CurrentVersion",
 EnvProgFiles[i].szRegValue,
 RRF_RT_REG_SZ,
nullptr,
 (LPBYTE)wchValue,
 &dwMaxBufferSize) == ERROR_SUCCESS)
 {
 wchValue[(dwMaxBufferSize / sizeof(wchValue[0])) - 1] = 0;
SetEnvironmentVariable(EnvProgFiles[i].szVariable, wchValue);
 }
 }
 }

// Initialize SxS for the process.
InitSideBySide();
}