SysRestore.c

/*
* SysRestore plug-in for NSIS
*
* Written by Jason Ross aka JasonFriday13 on the forums.
*
* SysRestore.c
*/

/*  Include the windows.h file, and the NSIS plugin header. */
#include <windows.h>
#include <srrestoreptapi.h>
#include "nsis\pluginapi.h" /* This means NSIS 2.42 or higher is required. */

/*  Handle for the plugin. */
HANDLE hInstance;

/*  Variables for the System Restore API */
PRESTOREPOINTINFO pRestPtInfo;
STATEMGRSTATUS SMgrStatus;
INT64 SequenceNumber = 0;

/*  Internal variables. */
BOOL RestorePointStarted = FALSE, Initialized = FALSE;

void Destroy(void)
{
	if (pRestPtInfo) GlobalFree(pRestPtInfo);
}

/*  Our callback function so that our dll stays loaded. */
UINT_PTR __cdecl NSISPluginCallback(enum NSPIM Event)
{
	if (Event == NSPIM_GUIUNLOAD)
		Destroy();

	return 0;
}

void Initialize(extra_parameters* xp)
{
	if (!Initialized)
	{
		xp->RegisterPluginCallback(hInstance, NSISPluginCallback);
		Initialized = TRUE;
	}
}

/*  This function is common to all functions. To reduce size,
having one copy instead of two saves space (I think). */
int SetRestorePoint(void)
{
	TCHAR *pTemp;

	pTemp = GlobalAlloc(GPTR, sizeof(TCHAR) * 64);
	SRSetRestorePoint(pRestPtInfo, &SMgrStatus);
	SequenceNumber = SMgrStatus.llSequenceNumber;
	wsprintf(pTemp, TEXT("%u"), SMgrStatus.nStatus);
	pushstring(pTemp);
	GlobalFree(pTemp);

	return SMgrStatus.nStatus;
}

/*  These functions must be internal to the dll,
because they use a global variable. It does
not work if these functions are exported. */
int Begin(BOOL Uninstaller)
{
	SecureZeroMemory(pRestPtInfo, sizeof(RESTOREPOINTINFO));
	SecureZeroMemory(&SMgrStatus, sizeof(STATEMGRSTATUS));

	/*  Initialize the RESTOREPOINTINFO structure. */
	pRestPtInfo->dwEventType = BEGIN_NESTED_SYSTEM_CHANGE;

	/*  Notify the system that changes are about to be made.
	An application is to be installed (or uninstalled). */
	if (Uninstaller)
		pRestPtInfo->dwRestorePtType = APPLICATION_UNINSTALL;
	else
		pRestPtInfo->dwRestorePtType = APPLICATION_INSTALL;

	/*  Set RestPtInfo.llSequenceNumber. */
	pRestPtInfo->llSequenceNumber = 0;

	/*  String to be displayed by System Restore for this restore point. */
	popstring(pRestPtInfo->szDescription);

	/*  Notify the system that changes are to be made and that
	the beginning of the restore point should be marked. */
	return SetRestorePoint();
}

int Finish(void)
{
	/*  Re-initialize the RESTOREPOINTINFO structure to notify the
	system that the operation is finished. */
	pRestPtInfo->dwEventType = END_NESTED_SYSTEM_CHANGE;

	/*  End the system change by returning the sequence number
	received from the first call to SRSetRestorePoint. */
	pRestPtInfo->llSequenceNumber = SequenceNumber;

	/*  Notify the system that the operation is done and that this
	is the end of the restore point. */
	return SetRestorePoint();
}

int Remove(void)
{
	int result;

	result = SRRemoveRestorePoint((DWORD)SequenceNumber);

	if (result == ERROR_SUCCESS)
		return 1;
	else
		return 0;
}

__declspec(dllexport) void StartRestorePoint(HWND hwndParent, int string_size, TCHAR *variables, stack_t **stacktop, extra_parameters* xp)
{
	EXDLL_INIT();
	Initialize(xp);

	/*  This is to prevent multiple calls to SRSetRestorePoint. */
	if (!RestorePointStarted)
	{
		if (Begin(FALSE) == ERROR_SUCCESS)
			RestorePointStarted = TRUE;
	}
	else
		pushint(1);
}

__declspec(dllexport) void StartUnRestorePoint(HWND hwndParent, int string_size, TCHAR *variables, stack_t **stacktop, extra_parameters* xp)
{
	EXDLL_INIT();
	Initialize(xp);

	/*  This is to prevent multiple calls to SRSetRestorePoint. */
	if (!RestorePointStarted)
	{
		if (Begin(TRUE) == ERROR_SUCCESS)
			RestorePointStarted = TRUE;
	}
	else
		pushint(1);
}

__declspec(dllexport) void FinishRestorePoint(HWND hwndParent, int string_size, TCHAR *variables, stack_t **stacktop, extra_parameters* xp)
{
	EXDLL_INIT();
	Initialize(xp);

	/*  This is to prevent multiple calls to SRSetRestorePoint. */
	if (RestorePointStarted)
	{
		if (Finish() == ERROR_SUCCESS)
			RestorePointStarted = FALSE;
	}
	else
		pushint(2);
}

void __declspec(dllexport) RemoveRestorePoint(HWND hwndParent, int string_size, TCHAR *variables, stack_t **stacktop, extra_parameters* xp)
{
	EXDLL_INIT();
	Initialize(xp);

	/*  This is to prevent multiple calls to SRSetRestorePoint. */
	if (SequenceNumber)
	{
		if (Remove())
			SequenceNumber = 0;
	}
	else
		pushint(3);
}

BOOL WINAPI _DllMainCRTStartup(HANDLE hInst, ULONG ul_reason_for_call, LPVOID lpReserved)
{
	hInstance = hInst;

	if (ul_reason_for_call == DLL_PROCESS_ATTACH)
		pRestPtInfo = GlobalAlloc(GPTR, sizeof(RESTOREPOINTINFO));

	if (ul_reason_for_call == DLL_PROCESS_DETACH)
		Destroy();

	return TRUE;
}