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refactored windows service "relauncher" (process watchdog), so that it's easier to understand.

This commit is contained in:
Nick Bolton 2013-10-14 16:29:02 +00:00
parent b9016bc1ae
commit 79ab428454
5 changed files with 216 additions and 226 deletions
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270
src/lib/platform/CMSWindowsRelauncher.cpp
View File

@ -47,13 +47,15 @@ CMSWindowsRelauncher::CMSWindowsRelauncher(
CIpcLogOutputter& ipcLogOutputter) :
m_thread(NULL),
m_autoDetectCommand(autoDetectCommand),
m_running(true),
m_monitoring(true),
m_commandChanged(false),
m_stdOutWrite(NULL),
m_stdOutRead(NULL),
m_ipcServer(ipcServer),
m_ipcLogOutputter(ipcLogOutputter),
m_elevateProcess(false)
m_elevateProcess(false),
m_launched(false),
m_failures(0)
{
}
@ -74,7 +76,7 @@ CMSWindowsRelauncher::startAsync()
void
CMSWindowsRelauncher::stop()
{
m_running = false;
m_monitoring = false;
m_thread->wait(5);
delete m_thread;
@ -94,8 +96,8 @@ CMSWindowsRelauncher::duplicateProcessToken(HANDLE process, LPSECURITY_ATTRIBUTE
&sourceToken);
if (!tokenRet) {
LOG((CLOG_ERR "could not open token, process handle: %d (error: %i)", process, GetLastError()));
return NULL;
LOG((CLOG_ERR "could not open token, process handle: %d", process));
throw XArch(new XArchEvalWindows());
}
LOG((CLOG_DEBUG "got token %i, duplicating", sourceToken));
@ -106,9 +108,8 @@ CMSWindowsRelauncher::duplicateProcessToken(HANDLE process, LPSECURITY_ATTRIBUTE
SecurityImpersonation, TokenPrimary, &newToken);
if (!duplicateRet) {
LOG((CLOG_ERR "could not duplicate token %i (error: %i)",
sourceToken, GetLastError()));
return NULL;
LOG((CLOG_ERR "could not duplicate token %i", sourceToken));
throw XArch(new XArchEvalWindows());
}
LOG((CLOG_DEBUG "duplicated, new token: %i", newToken));
@ -128,13 +129,12 @@ CMSWindowsRelauncher::getUserToken(LPSECURITY_ATTRIBUTES security)
(m_elevateProcess ? "elevation required" : "at login screen")));
HANDLE process;
if (m_session.isProcessInSession("winlogon.exe", &process)) {
if (!m_session.isProcessInSession("winlogon.exe", &process)) {
throw XMSWindowsWatchdogError("cannot get user token without winlogon.exe");
}
return duplicateProcessToken(process, security);
}
else {
return NULL;
}
}
else {
LOG((CLOG_DEBUG "getting non-elevated token"));
return m_session.getUserToken(security);
@ -153,8 +153,6 @@ CMSWindowsRelauncher::mainLoop(void*)
sendSasFunc = (SendSas)GetProcAddress(sasLib, "SendSAS");
}
bool launched = false;
SECURITY_ATTRIBUTES saAttr;
saAttr.nLength = sizeof(SECURITY_ATTRIBUTES);
saAttr.bInheritHandle = TRUE;
@ -164,78 +162,15 @@ CMSWindowsRelauncher::mainLoop(void*)
throw XArch(new XArchEvalWindows());
}
PROCESS_INFORMATION pi;
ZeroMemory(&pi, sizeof(PROCESS_INFORMATION));
ZeroMemory(&m_processInfo, sizeof(PROCESS_INFORMATION));
int failures = 0;
while (m_monitoring) {
while (m_running) {
// relaunch if the process was running but has stopped unexpectedly.
if ((m_launched && !isProcessRunning()) || m_session.hasChanged() || m_commandChanged) {
HANDLE sendSasEvent = 0;
if (sasLib && sendSasFunc) {
// can't we just create one event? seems weird creating a new
// event every second...
sendSasEvent = CreateEvent(NULL, FALSE, FALSE, "Global\\SendSAS");
}
m_session.updateNewSessionId();
bool running = false;
if (launched) {
DWORD exitCode;
GetExitCodeProcess(pi.hProcess, &exitCode);
running = (exitCode == STILL_ACTIVE);
if (!running) {
failures++;
LOG((CLOG_INFO "detected application not running, pid=%d, failures=%d", pi.dwProcessId, failures));
// increasing backoff period, maximum of 10 seconds.
int timeout = (failures * 2) < 10 ? (failures * 2) : 10;
LOG((CLOG_DEBUG "waiting, backoff period is %d seconds", timeout));
ARCH->sleep(timeout);
// double check, in case process started after we waited.
GetExitCodeProcess(pi.hProcess, &exitCode);
running = (exitCode == STILL_ACTIVE);
}
else {
// reset failures when running.
failures = 0;
}
}
// relaunch if it was running but has stopped unexpectedly.
bool stoppedRunning = (launched && !running);
if (stoppedRunning || m_session.hasChanged() || m_commandChanged) {
m_commandChanged = false;
if (launched) {
LOG((CLOG_DEBUG "closing existing process to make way for new one"));
shutdownProcess(pi.hProcess, pi.dwProcessId, 20);
launched = false;
}
// ok, this is now the active session (forget the old one if any)
m_session.updateActiveSession();
SECURITY_ATTRIBUTES sa;
ZeroMemory(&sa, sizeof(SECURITY_ATTRIBUTES));
HANDLE userToken = getUserToken(&sa);
if (userToken == NULL) {
// HACK: trigger retry mechanism.
launched = true;
continue;
}
std::string cmd = command();
if (cmd == "") {
std::string command = getCommand();
if (command.empty()) {
// this appears on first launch when the user hasn't configured
// anything yet, so don't show it as a warning, only show it as
// debug to devs to let them know why nothing happened.
@ -243,8 +178,102 @@ CMSWindowsRelauncher::mainLoop(void*)
continue;
}
// in case reusing process info struct
ZeroMemory(&pi, sizeof(PROCESS_INFORMATION));
try {
startProcess(command);
}
catch (XArch& e) {
LOG((CLOG_ERR "failed to launch, error: %s", e.what().c_str()));
m_launched = false;
continue;
}
catch (XSynergy& e) {
LOG((CLOG_ERR "failed to launch, error: %s", e.what()));
m_launched = false;
continue;
}
}
if (sendSasFunc != NULL) {
HANDLE sendSasEvent = CreateEvent(NULL, FALSE, FALSE, "Global\\SendSAS");
if (sendSasEvent != NULL) {
// use SendSAS event to wait for next session (timeout 1 second).
if (WaitForSingleObject(sendSasEvent, 1000) == WAIT_OBJECT_0) {
LOG((CLOG_DEBUG "calling SendSAS"));
sendSasFunc(FALSE);
}
CloseHandle(sendSasEvent);
continue;
}
}
// if the sas event failed, wait by sleeping.
ARCH->sleep(1);
}
if (m_launched) {
LOG((CLOG_DEBUG "terminated running process on exit"));
shutdownProcess(m_processInfo.hProcess, m_processInfo.dwProcessId, 20);
}
LOG((CLOG_DEBUG "relauncher main thread finished"));
}
bool
CMSWindowsRelauncher::isProcessRunning()
{
bool running;
if (m_launched) {
DWORD exitCode;
GetExitCodeProcess(m_processInfo.hProcess, &exitCode);
running = (exitCode == STILL_ACTIVE);
if (!running) {
m_failures++;
LOG((CLOG_INFO
"detected application not running, pid=%d, failures=%d",
m_processInfo.dwProcessId, m_failures));
// increasing backoff period, maximum of 10 seconds.
int timeout = (m_failures * 2) < 10 ? (m_failures * 2) : 10;
LOG((CLOG_DEBUG "waiting, backoff period is %d seconds", timeout));
ARCH->sleep(timeout);
// double check, in case process started after we waited.
GetExitCodeProcess(m_processInfo.hProcess, &exitCode);
running = (exitCode == STILL_ACTIVE);
}
else {
// reset failures when running.
m_failures = 0;
}
}
return running;
}
void
CMSWindowsRelauncher::startProcess(std::string& command)
{
m_commandChanged = false;
if (m_launched) {
LOG((CLOG_DEBUG "closing existing process to make way for new one"));
shutdownProcess(m_processInfo.hProcess, m_processInfo.dwProcessId, 20);
m_launched = false;
}
m_session.updateActiveSession();
SECURITY_ATTRIBUTES sa;
ZeroMemory(&sa, sizeof(SECURITY_ATTRIBUTES));
HANDLE userToken = getUserToken(&sa);
// clear, as we're reusing process info struct
ZeroMemory(&m_processInfo, sizeof(PROCESS_INFORMATION));
STARTUPINFO si;
ZeroMemory(&si, sizeof(STARTUPINFO));
@ -257,9 +286,8 @@ CMSWindowsRelauncher::mainLoop(void*)
LPVOID environment;
BOOL blockRet = CreateEnvironmentBlock(&environment, userToken, FALSE);
if (!blockRet) {
LOG((CLOG_ERR "could not create environment block (error: %i)",
GetLastError()));
continue;
LOG((CLOG_ERR "could not create environment block"));
throw XArch(new XArchEvalWindows);
}
DWORD creationFlags =
@ -270,48 +298,26 @@ CMSWindowsRelauncher::mainLoop(void*)
// re-launch in current active user session
LOG((CLOG_INFO "starting new process"));
BOOL createRet = CreateProcessAsUser(
userToken, NULL, LPSTR(cmd.c_str()),
userToken, NULL, LPSTR(command.c_str()),
&sa, NULL, TRUE, creationFlags,
environment, NULL, &si, &pi);
environment, NULL, &si, &m_processInfo);
DestroyEnvironmentBlock(environment);
CloseHandle(userToken);
if (!createRet) {
LOG((CLOG_ERR "could not launch (error: %i)", GetLastError()));
continue;
LOG((CLOG_ERR "could not launch"));
throw XArch(new XArchEvalWindows);
}
else {
LOG((CLOG_DEBUG "launched in session %i (cmd: %s)",
m_session.getActiveSessionId(), cmd.c_str()));
launched = true;
LOG((CLOG_DEBUG "started process, session=%i, command=%s",
m_session.getActiveSessionId(), command.c_str()));
m_launched = true;
}
}
if (sendSasEvent) {
// use SendSAS event to wait for next session.
if (WaitForSingleObject(sendSasEvent, 1000) == WAIT_OBJECT_0 && sendSasFunc) {
LOG((CLOG_DEBUG "calling SendSAS"));
sendSasFunc(FALSE);
}
CloseHandle(sendSasEvent);
}
else {
// check for session change every second.
ARCH->sleep(1);
}
}
if (launched) {
LOG((CLOG_DEBUG "terminated running process on exit"));
shutdownProcess(pi.hProcess, pi.dwProcessId, 20);
}
LOG((CLOG_DEBUG "relauncher main thread finished"));
}
void
CMSWindowsRelauncher::command(const std::string& command, bool elevate)
CMSWindowsRelauncher::setCommand(const std::string& command, bool elevate)
{
LOG((CLOG_INFO "service command updated"));
m_command = command;
@ -320,7 +326,7 @@ CMSWindowsRelauncher::command(const std::string& command, bool elevate)
}
std::string
CMSWindowsRelauncher::command() const
CMSWindowsRelauncher::getCommand() const
{
if (!m_autoDetectCommand) {
return m_command;
@ -351,7 +357,7 @@ CMSWindowsRelauncher::outputLoop(void*)
// +1 char for \0
CHAR buffer[kOutputBufferSize + 1];
while (m_running) {
while (m_monitoring) {
DWORD bytesRead;
BOOL success = ReadFile(m_stdOutRead, buffer, kOutputBufferSize, &bytesRead, NULL);
@ -377,16 +383,17 @@ CMSWindowsRelauncher::shutdownProcess(HANDLE handle, DWORD pid, int timeout)
{
DWORD exitCode;
GetExitCodeProcess(handle, &exitCode);
if (exitCode != STILL_ACTIVE)
if (exitCode != STILL_ACTIVE) {
return;
}
CIpcShutdownMessage shutdown;
m_ipcServer.send(shutdown, kIpcClientNode);
// wait for process to exit gracefully.
double start = ARCH->time();
while (true)
{
while (true) {
GetExitCodeProcess(handle, &exitCode);
if (exitCode != STILL_ACTIVE) {
// yay, we got a graceful shutdown. there should be no hook in use errors!
@ -417,9 +424,8 @@ CMSWindowsRelauncher::shutdownExistingProcesses()
// first we need to take a snapshot of the running processes
HANDLE snapshot = CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, 0);
if (snapshot == INVALID_HANDLE_VALUE) {
LOG((CLOG_ERR "could not get process snapshot (error: %i)",
GetLastError()));
return;
LOG((CLOG_ERR "could not get process snapshot"));
throw XArch(new XArchEvalWindows);
}
PROCESSENTRY32 entry;
@ -429,9 +435,8 @@ CMSWindowsRelauncher::shutdownExistingProcesses()
// unlikely we can go any further
BOOL gotEntry = Process32First(snapshot, &entry);
if (!gotEntry) {
LOG((CLOG_ERR "could not get first process entry (error: %i)",
GetLastError()));
return;
LOG((CLOG_ERR "could not get first process entry"));
throw XArch(new XArchEvalWindows);
}
// now just iterate until we can find winlogon.exe pid
@ -457,9 +462,8 @@ CMSWindowsRelauncher::shutdownExistingProcesses()
if (err != ERROR_NO_MORE_FILES) {
// only worry about error if it's not the end of the snapshot
LOG((CLOG_ERR "could not get subsiquent process entry (error: %i)",
GetLastError()));
return;
LOG((CLOG_ERR "could not get subsiquent process entry"));
throw XArch(new XArchEvalWindows);
}
}
}

27
src/lib/platform/CMSWindowsRelauncher.h
View File

@ -16,6 +16,8 @@
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
// TODO: rename class to CMSWindowsWatchdog
#pragma once
#define WIN32_LEAN_AND_MEAN
@ -23,6 +25,7 @@
#include <Windows.h>
#include <string>
#include <list>
#include "XSynergy.h"
class CThread;
class CIpcLogOutputter;
@ -37,8 +40,8 @@ public:
virtual ~CMSWindowsRelauncher();
void startAsync();
std::string command() const;
void command(const std::string& command, bool elevate);
std::string getCommand() const;
void setCommand(const std::string& command, bool elevate);
void stop();
private:
@ -48,12 +51,15 @@ private:
void shutdownExistingProcesses();
HANDLE duplicateProcessToken(HANDLE process, LPSECURITY_ATTRIBUTES security);
HANDLE getUserToken(LPSECURITY_ATTRIBUTES security);
void startProcess(std::string& command);
bool isProcessRunning();
void sendSas();
private:
CThread* m_thread;
bool m_autoDetectCommand;
std::string m_command;
bool m_running;
bool m_monitoring;
bool m_commandChanged;
HANDLE m_stdOutWrite;
HANDLE m_stdOutRead;
@ -62,4 +68,19 @@ private:
CIpcLogOutputter& m_ipcLogOutputter;
bool m_elevateProcess;
CMSWindowsSession m_session;
bool m_launched;
PROCESS_INFORMATION m_processInfo;
int m_failures;
};
//! Relauncher error
/*!
An error occured in the process watchdog.
*/
class XMSWindowsWatchdogError : public XSynergy {
public:
XMSWindowsWatchdogError(const CString& msg) : XSynergy(msg) { }
// XBase overrides
virtual CString getWhat() const throw() { return what(); }
};

70
src/lib/platform/CMSWindowsSession.cpp
View File

@ -19,10 +19,11 @@
#include "CLog.h"
#include <Tlhelp32.h>
#include <Wtsapi32.h>
#include "XSynergy.h"
#include "XArchWindows.h"
CMSWindowsSession::CMSWindowsSession() :
m_sessionId(-1),
m_newSessionId(-1)
m_activeSessionId(-1)
{
}
@ -30,31 +31,14 @@ CMSWindowsSession::~CMSWindowsSession()
{
}
DWORD
CMSWindowsSession::getSessionId()
{
return WTSGetActiveConsoleSessionId();
}
BOOL
bool
CMSWindowsSession::isProcessInSession(const char* name, PHANDLE process = NULL)
{
BOOL result = isProcessInSession_(name, process);
if (!result) {
LOG((CLOG_ERR "could not find winlogon in session %i", m_sessionId));
}
return result;
}
BOOL
CMSWindowsSession::isProcessInSession_(const char* name, PHANDLE process = NULL)
{
// first we need to take a snapshot of the running processes
HANDLE snapshot = CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, 0);
if (snapshot == INVALID_HANDLE_VALUE) {
LOG((CLOG_ERR "could not get process snapshot (error: %i)",
GetLastError()));
return 0;
LOG((CLOG_ERR "could not get process snapshot"));
throw XArch(new XArchEvalWindows());
}
PROCESSENTRY32 entry;
@ -64,9 +48,8 @@ CMSWindowsSession::isProcessInSession_(const char* name, PHANDLE process = NULL)
// unlikely we can go any further
BOOL gotEntry = Process32First(snapshot, &entry);
if (!gotEntry) {
LOG((CLOG_ERR "could not get first process entry (error: %i)",
GetLastError()));
return 0;
LOG((CLOG_ERR "could not get first process entry"));
throw XArch(new XArchEvalWindows());
}
// used to record process names for debug info
@ -84,13 +67,12 @@ CMSWindowsSession::isProcessInSession_(const char* name, PHANDLE process = NULL)
entry.th32ProcessID, &processSessionId);
if (!pidToSidRet) {
LOG((CLOG_ERR "could not get session id for process id %i (error: %i)",
entry.th32ProcessID, GetLastError()));
return 0;
LOG((CLOG_ERR "could not get session id for process id %i", entry.th32ProcessID));
throw XArch(new XArchEvalWindows());
}
// only pay attention to processes in the active session
if (processSessionId == m_sessionId) {
if (processSessionId == m_activeSessionId) {
// store the names so we can record them for debug
nameList.push_back(entry.szExeFile);
@ -109,9 +91,8 @@ CMSWindowsSession::isProcessInSession_(const char* name, PHANDLE process = NULL)
if (err != ERROR_NO_MORE_FILES) {
// only worry about error if it's not the end of the snapshot
LOG((CLOG_ERR "could not get subsiquent process entry (error: %i)",
GetLastError()));
return 0;
LOG((CLOG_ERR "could not get next process entry"));
throw XArch(new XArchEvalWindows());
}
}
}
@ -124,19 +105,20 @@ CMSWindowsSession::isProcessInSession_(const char* name, PHANDLE process = NULL)
}
LOG((CLOG_DEBUG "processes in session %d: %s",
m_sessionId, nameListJoin.c_str()));
m_activeSessionId, nameListJoin.c_str()));
CloseHandle(snapshot);
if (pid) {
if (process != NULL) {
// now get the process, which we'll use to get the process token.
LOG((CLOG_DEBUG "found %s in session %i", name, m_sessionId));
LOG((CLOG_DEBUG "found %s in session %i", name, m_activeSessionId));
*process = OpenProcess(MAXIMUM_ALLOWED, FALSE, pid);
}
return true;
}
else {
LOG((CLOG_ERR "could not find %s in session %i", name, m_activeSessionId));
return false;
}
}
@ -145,9 +127,9 @@ HANDLE
CMSWindowsSession::getUserToken(LPSECURITY_ATTRIBUTES security)
{
HANDLE sourceToken;
if (!WTSQueryUserToken(m_sessionId, &sourceToken)) {
LOG((CLOG_ERR "could not get token from session %d (error: %i)", m_sessionId, GetLastError()));
return 0;
if (!WTSQueryUserToken(m_activeSessionId, &sourceToken)) {
LOG((CLOG_ERR "could not get token from session %d", m_activeSessionId));
throw XArch(new XArchEvalWindows);
}
HANDLE newToken;
@ -155,8 +137,8 @@ CMSWindowsSession::getUserToken(LPSECURITY_ATTRIBUTES security)
sourceToken, TOKEN_ASSIGN_PRIMARY | TOKEN_ALL_ACCESS, security,
SecurityImpersonation, TokenPrimary, &newToken)) {
LOG((CLOG_ERR "could not duplicate token (error: %i)", GetLastError()));
return 0;
LOG((CLOG_ERR "could not duplicate token"));
throw XArch(new XArchEvalWindows);
}
LOG((CLOG_DEBUG "duplicated, new token: %i", newToken));
@ -166,17 +148,11 @@ CMSWindowsSession::getUserToken(LPSECURITY_ATTRIBUTES security)
BOOL
CMSWindowsSession::hasChanged()
{
return ((m_newSessionId != m_sessionId) && (m_newSessionId != -1));
}
void
CMSWindowsSession::updateNewSessionId()
{
m_newSessionId = getSessionId();
return (m_activeSessionId != WTSGetActiveConsoleSessionId());
}
void
CMSWindowsSession::updateActiveSession()
{
m_sessionId = m_newSessionId;
m_activeSessionId = WTSGetActiveConsoleSessionId();
}

27
src/lib/platform/CMSWindowsSession.h
View File

@ -25,31 +25,20 @@ public:
CMSWindowsSession();
~CMSWindowsSession();
//! Get session ID from Windows
/*!
This gets the physical session (the one the keyboard and
mouse is connected to), sometimes this returns -1.
*/
DWORD getSessionId();
BOOL isProcessInSession(const char* name, PHANDLE process);
HANDLE getUserToken(LPSECURITY_ATTRIBUTES security);
DWORD getActiveSessionId() { return m_sessionId; }
//!
/*!
only enter here when id changes, and the session isn't -1, which
may mean that there is no active session.
Returns true if the session ID has changed since updateActiveSession was called.
*/
BOOL hasChanged();
void updateNewSessionId();
bool isProcessInSession(const char* name, PHANDLE process);
HANDLE getUserToken(LPSECURITY_ATTRIBUTES security);
DWORD getActiveSessionId() { return m_activeSessionId; }
void updateActiveSession();
private:
BOOL isProcessInSession_(const char* name, PHANDLE process);
private:
DWORD m_sessionId;
DWORD m_newSessionId;
DWORD m_activeSessionId;
};

4
src/lib/synergy/CDaemonApp.cpp
View File

@ -229,7 +229,7 @@ CDaemonApp::mainLoop(bool logToFile)
bool elevate = ARCH->setting("Elevate") == "1";
if (command != "") {
LOG((CLOG_INFO "using last known command: %s", command.c_str()));
m_relauncher->command(command, elevate);
m_relauncher->setCommand(command, elevate);
}
m_relauncher->startAsync();
@ -334,7 +334,7 @@ CDaemonApp::handleIpcMessage(const CEvent& e, void*)
// tell the relauncher about the new command. this causes the
// relauncher to stop the existing command and start the new
// command.
m_relauncher->command(command, cm->elevate());
m_relauncher->setCommand(command, cm->elevate());
#endif
break;
}