gpuPlotGenerator/PlotsFile-win.cpp at master · bhamon/gpuPlotGenerator · GitHub

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#include <stdexcept>
#include <sstream>
#include <Windows.h>

#include "constants.h"
#include "PlotsFile.h"

namespace cryo {
namespace gpuPlotGenerator {

bool setPrivilege() {
	LUID luid;
	if(!LookupPrivilegeValue(0, SE_MANAGE_VOLUME_NAME, &luid)) {
		return false;
	}

	HANDLE hToken;
	if(!OpenProcessToken(GetCurrentProcess(), TOKEN_ADJUST_PRIVILEGES | TOKEN_QUERY, &hToken)) {
		return false;
	}

	TOKEN_PRIVILEGES tp;
	tp.PrivilegeCount = 1;
	tp.Privileges[0].Luid = luid;
	tp.Privileges[0].Attributes = SE_PRIVILEGE_ENABLED;
	if(!AdjustTokenPrivileges(hToken, 0, &tp, sizeof(TOKEN_PRIVILEGES), static_cast<PTOKEN_PRIVILEGES>(0), static_cast<PDWORD>(0))) {
		return false;
	}

	if(GetLastError() == ERROR_NOT_ALL_ASSIGNED) {
		return false;
	}

	return true;
}

void PlotsFile::preallocate(const std::string& p_path, unsigned long long p_size) throw (std::exception) {
	bool granted = setPrivilege();

	HANDLE out = CreateFileA(p_path.c_str(), GENERIC_WRITE, 0, 0, OPEN_ALWAYS, FILE_FLAG_NO_BUFFERING, 0);
	if(out == INVALID_HANDLE_VALUE) {
		std::ostringstream msg;
		msg << "Unable to open the output file: " << GetLastError();
		throw std::runtime_error(msg.str().c_str());
	}

	LARGE_INTEGER targetPointer;
	targetPointer.QuadPart = p_size;
	SetFilePointerEx(out, targetPointer, 0, FILE_BEGIN);
	if(SetEndOfFile(out) == 0) {
		CloseHandle(out);

		std::ostringstream msg;
		msg << "Unable to extend output file: " << GetLastError();
		throw std::runtime_error(msg.str().c_str());
	}

	if(granted) {
		if(SetFileValidData(out, p_size) == 0) {
			CloseHandle(out);

			std::ostringstream msg;
			msg << "Unable to prevent zero filling: " << GetLastError();
			throw std::runtime_error(msg.str().c_str());
		}
	}

	CloseHandle(out);
}

}}