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ff8840491c
Bug#33031 app linked to libmysql.lib crash if run as service in vista under localsystem There are some problems using DllMain hook functions on Windows that automatically do global and per-thread initialization for libmysqld.dll 1)per-thread initialization(DLL_THREAD_ATTACH) MySQL internally counts number of active threads that and causes a delay in in my_end() if not all threads are exited. But,there are threads that can be started either by Windows internally (often in TCP/IP scenarios) or by user himself - those threads are not necessarily using libmysql.dll functionality, but nonetheless the contribute to the count of open threads. 2)process-initialization (DLL_PROCESS_ATTACH) my_init() calls WSAStartup that itself loads DLLs and can lead to a deadlock in Windows loader. Fix is to remove dll initialization code from libmysql.dll in general case. I still leave an environment variable LIBMYSQL_DLLINIT, which if set to any value will cause the old behavior (DLL init hooks will be called). This env.variable exists only to prevent breakage of existing Windows-only applications that don't do mysql_thread_init() and work ok today. Use of LIBMYSQL_DLLINIT is discouraged and it will be removed in 6.0
126 lines
3.4 KiB
C
126 lines
3.4 KiB
C
/* Copyright (C) 2000-2004 MySQL AB
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation.
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There are special exceptions to the terms and conditions of the GPL as it
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is applied to this software. View the full text of the exception in file
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EXCEPTIONS-CLIENT in the directory of this software distribution.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
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/*
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** Handling initialization of the dll library
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*/
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#include <my_global.h>
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#include <my_sys.h>
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#include <my_pthread.h>
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static my_bool libmysql_inited=0;
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void libmysql_init(void)
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{
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if (libmysql_inited)
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return;
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libmysql_inited=1;
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my_init();
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{
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DBUG_ENTER("libmysql_init");
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#ifdef LOG_ALL
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DBUG_PUSH("d:t:S:O,c::\\tmp\\libmysql.log");
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#else
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if (getenv("LIBMYSQL_LOG") != NULL)
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DBUG_PUSH(getenv("LIBMYSQL_LOG"));
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#endif
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DBUG_VOID_RETURN;
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}
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}
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#ifdef __WIN__
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static int inited=0,threads=0;
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HINSTANCE NEAR s_hModule; /* Saved module handle */
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DWORD main_thread;
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BOOL APIENTRY LibMain(HANDLE hInst,DWORD ul_reason_being_called,
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LPVOID lpReserved)
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{
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switch (ul_reason_being_called) {
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case DLL_PROCESS_ATTACH: /* case of libentry call in win 3.x */
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if (!inited++)
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{
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s_hModule=hInst;
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libmysql_init();
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main_thread=GetCurrentThreadId();
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}
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break;
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case DLL_THREAD_ATTACH:
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threads++;
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my_thread_init();
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break;
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case DLL_PROCESS_DETACH: /* case of wep call in win 3.x */
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if (!--inited) /* Safety */
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{
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/* my_thread_init() */ /* This may give extra safety */
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my_end(0);
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}
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break;
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case DLL_THREAD_DETACH:
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/* Main thread will free by my_end() */
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threads--;
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if (main_thread != GetCurrentThreadId())
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my_thread_end();
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break;
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default:
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break;
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} /* switch */
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return TRUE;
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UNREFERENCED_PARAMETER(lpReserved);
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} /* LibMain */
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static BOOL do_libmain;
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int __stdcall DllMain(HANDLE hInst,DWORD ul_reason_being_called,LPVOID lpReserved)
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{
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/*
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Unless environment variable LIBMYSQL_DLLINIT is set, do nothing.
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The environment variable is checked once, during the first call to DllMain()
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(in DLL_PROCESS_ATTACH hook).
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*/
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if (ul_reason_being_called == DLL_PROCESS_ATTACH)
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do_libmain = (getenv("LIBMYSQL_DLLINIT") != NULL);
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if (do_libmain)
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return LibMain(hInst,ul_reason_being_called,lpReserved);
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return TRUE;
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}
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#elif defined(WINDOWS)
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/****************************************************************************
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** This routine is called by LIBSTART.ASM at module load time. All it
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** does in this sample is remember the DLL module handle. The module
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** handle is needed if you want to do things like load stuff from the
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** resource file (for instance string resources).
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****************************************************************************/
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int _export FAR PASCAL libmain(HANDLE hModule,short cbHeapSize,
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UCHAR FAR *lszCmdLine)
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{
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s_hModule = hModule;
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libmysql_init();
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return TRUE;
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}
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#endif
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