无法从服务关闭用户会话中的进程

Question

该架构是一种服务，可以在具有系统权限的用户会话中的进程组中启动进程，代码片段 1。

当服务需要自行停止时，我想向子进程发送一个信号，让它有机会优雅地关闭，代码片段 2。

问题是它似乎根本没有发送信号，没有任何明显的错误代码。我已经测试了从命令提示符运行的子进程，ctrl+break 工作得很好。

代码片段 1

PROCESS_INFORMATION processInfo;
ZeroMemory(&processInfo, sizeof(PROCESS_INFORMATION));
STARTUPINFO si;
ZeroMemory(&si, sizeof(STARTUPINFO));
si.cb = sizeof(STARTUPINFO);
si.lpDesktop = "winsta0\Default";
si.dwFlags |= STARTF_USESTDHANDLES;
LPVOID environment;
BOOL createRet = CreateEnvironmentBlock(&environment, userToken, FALSE);
if (!createRet) {
throw std::runtime_error("Failed to create environment block");
}
DWORD creationFlags =
NORMAL_PRIORITY_CLASS |
CREATE_NO_WINDOW |
CREATE_UNICODE_ENVIRONMENT |
CREATE_NEW_PROCESS_GROUP; // this create a process in a group
// launch a process in the user session
// the toke is a system privilege toke within the user session
createRet = CreateProcessAsUser(
userToken, NULL, LPSTR(command.c_str()),
sa, NULL, TRUE, creationFlags,
environment, NULL, &si, &processInfo);
if (!createRet) {
throw std::runtime_error("Failed to create the service in user session");
}
m_serviceGroupId = processInfo.dwProcessId;
DestroyEnvironmentBlock(environment);
CloseHandle(userToken);

代码片段 2

if (m_serviceGroupId == 0) {
return;
}
HANDLE process;
const UINT kExitCode = 0;
const UINT kShutdownTimeout = 3000;
if (findProcessInSession(kServiceProcess, &process, getActiveSession())) {
BOOL r = GenerateConsoleCtrlEvent(CTRL_BREAK_EVENT, m_serviceGroupId);
// this won't success if I don't specifically call AllocConsole() in the constructor
if (!r) {
writeEventErrorLog(GetLastErrorAsString().c_str());
}
DWORD exitCode = WaitForSingleObject(process, kShutdownTimeout);
if (exitCode != WAIT_OBJECT_0) {
// always fall into forceful shutdown
writeEventErrorLog("Forcefully shutdown synergy service");
// GetLastErrorAsString returns empty string
writeEventErrorLog(GetLastErrorAsString().c_str());
if (!TerminateProcess(process, kExitCode)) {
writeEventErrorLog("Failed to shutdown synergy service");
}
}
}
m_serviceGroupId = 0;

Answer 1

你的方法不起作用，因为服务进程和子进程不在同一会话中，因此请考虑 Windows 事件。看看 CreateEvent 和 SetEvent。

当您的服务进程启动时，调用 CreateEvent((，例如：

HANDLE hEvent = CreateEvent(NULL, FALSE, FALSE, "Global\myevent");

当子进程启动时，调用 CreateEvent((，并启动一个线程来捕获信号：

//The lpName should be identical with that in service process
HANDLE hEvent = CreateEvent(NULL, FALSE, FALSE, "Global\myevent");
std::thread mythread([hEvent] {
WaitForSingleObject(hEvent, INFINITE);
//then exit your child process gracefully
});

每当打算停止子进程时，只需在服务进程中调用 SetEvent((：

SetEvent(hEvent);

将 bManualReset 设置为 TRUE，然后服务可以同时向不同的子进程发送信号。