差異處
這裏顯示兩個版本的差異處。
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cpp:sc:queryservicelockstatus [2016/04/19 13:55] tony |
cpp:sc:queryservicelockstatus [2023/06/25 09:48] |
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| - | {{tag>cpp Windows}} | ||
| - | ====== QueryServiceLockStatus ====== | ||
| - | ===== Introduction ===== | ||
| - | 某些third-party api會在runtime去新增service，以減少使用者在安裝上的負擔。然而在系統重新啟動時，SCM會lock service database，如果新增service將會造成block。此源自: [[https://msdn.microsoft.com/zh-tw/library/windows/desktop/ms686321(v=vs.85).aspx|link]] | ||
| - | <code> | ||
| - | A service cannot call StartService during initialization. The reason is that the SCM locks the' | ||
| - | service control database during initialization, so a call to StartService will block. After the | ||
| - | service reports to the SCM that it has successfully started, it can call StartService. | ||
| - | </code> | ||
| - | 因此，我們可以先檢查SCM database是否lock，再決定我們接下來該怎麼做。 | ||
| - | ===== How to? ===== | ||
| - | <code cpp> | ||
| - | BOOL IsSCMRelease(){ | ||
| - | SC_HANDLE hSCManager; | ||
| - | LPQUERY_SERVICE_LOCK_STATUS hStatus; | ||
| - | DWORD dwBytesNeeded; | ||
| - | BOOL ret; | ||
| - | hSCManager=OpenSCManager(NULL, NULL, SC_MANAGER_QUERY_LOCK_STATUS); | ||
| - | |||
| - | if (hSCManager) { | ||
| - | hStatus = (LPQUERY_SERVICE_LOCK_STATUS) LocalAlloc(LPTR, sizeof(QUERY_SERVICE_LOCK_STATUS)+256); | ||
| - | if( hStatus == NULL ) { | ||
| - | clog << "LocalAlloc failed. Error: " << GetLastError() << endl; | ||
| - | return FALSE; | ||
| - | } | ||
| - | |||
| - | if( !QueryServiceLockStatus( hSCManager, hStatus, sizeof(QUERY_SERVICE_LOCK_STATUS)+256, &dwBytesNeeded)){ | ||
| - | clog << "Can't query lock status. Error: " << GetLastError() << endl; | ||
| - | ret = FALSE; | ||
| - | } else { | ||
| - | ret = hStatus->fIsLocked == 0; | ||
| - | } | ||
| - | |||
| - | CloseServiceHandle(hSCManager); | ||
| - | LocalFree(hStatus); | ||
| - | return ret; | ||
| - | } | ||
| - | |||
| - | clog << "Can't open SCManager." << endl; | ||
| - | |||
| - | return FALSE; | ||
| - | } | ||
| - | |||
| - | </code> | ||
| - | 如果要透過command line，可以使用sc querylock | ||
| - | <code bash> | ||
| - | C:\Users\tonylin>chcp 437 & sc querylock | ||
| - | Active code page: 437 | ||
| - | [SC] QueryServiceLockStatus SUCCESS | ||
| - | IsLocked : FALSE | ||
| - | LockOwner : | ||
| - | LockDuration : 0 (seconds since acquired) | ||
| - | </code> | ||
| - | ===== Reference ===== | ||
| - | * [[https://msdn.microsoft.com/zh-tw/library/windows/desktop/ms684938(v=vs.85).aspx|MSDN - QueryServiceLockStatus]] | ||
| - | * [[https://msdn.microsoft.com/zh-tw/library/windows/desktop/ms686321(v=vs.85).aspx|MSDN - StartService]] | ||
| - | * [[https://msdn.microsoft.com/zh-tw/library/windows/desktop/ms685104(v=vs.85).aspx|MSDN - SCM Handles]] | ||
| - | * [[http://www.tenouk.com/cpluscodesnippet/changewindowserviceconfig.html|sample code]] | ||
| - | ===== ===== | ||
| - | ---- | ||
| - | \\ | ||
| - | ~~DISQUS~~ | ||
