Source code of Windows XP (NT5)
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/*++
Copyright (c) 2000 Microsoft Corporation
Module Name:
WinExecRaceConditionFix.cpp
Abstract:
This Shim uses the command line parameter to indicate how it works:
If passed 'nowait', it enables the WinExec functionality:
The WinExec in this DLL is identical to the actual WinExec API but without
the WaitForUserinputIdleRoutine, which inverts an almost race condition
between the launcher and the launchee. 9x does not have this wait, so the
programmers were able to (possibly inadvertently) use the same window class
exclusion matching for both since, in 9x, the launcher kills itself before
the launchee can check for a duplicate window. This shim leaves out the
wait condition, allowing 9x like behavior.
If passed a number, it sleeps in initialization for that number of
microseconds.
Notes:
This shim has no app specific information.
History:
03/22/2000 a-charr Created
--*/
#include "precomp.h"
IMPLEMENT_SHIM_BEGIN(WinExecRaceConditionFix)
#include "ShimHookMacro.h"
APIHOOK_ENUM_BEGIN
APIHOOK_ENUM_ENTRY(WinExec)
APIHOOK_ENUM_END
/*++
This function breaks into WinExec and calls CreateProcessA without
waiting afterward.
--*/
UINT
APIHOOK(WinExec)(
LPCSTR lpCmdLine,
UINT uCmdShow
)
/*++
This is a direct copy of the actual WinExec API minus two sections,
1. UserWaitForInputIdleRoutine is removed because it is waiting for the spawned
process to begin its event loop, but the spawned process is killing itself
before starting the event loop because the spawning process is waiting for
it.
2. Some app specific appcompat code that seems to be hanging around from who
knows when.
--*/
{
STARTUPINFOA StartupInfo;
PROCESS_INFORMATION ProcessInformation;
BOOL CreateProcessStatus;
DWORD ErrorCode;
LOGN(
eDbgLevelInfo,
"[WinExec] Called. Returning without waiting for new process to start.");
RtlZeroMemory(&StartupInfo,sizeof(StartupInfo));
StartupInfo.cb = sizeof(StartupInfo);
StartupInfo.dwFlags = STARTF_USESHOWWINDOW;
StartupInfo.wShowWindow = (WORD)uCmdShow;
CreateProcessStatus = CreateProcessA(
NULL,
(LPSTR)lpCmdLine,
NULL,
NULL,
FALSE,
0,
NULL,
NULL,
&StartupInfo,
&ProcessInformation);
if (CreateProcessStatus) {
return 33;
} else {
ErrorCode = GetLastError();
switch (ErrorCode) {
case ERROR_FILE_NOT_FOUND:
return 2;
case ERROR_PATH_NOT_FOUND:
return 3;
case ERROR_BAD_EXE_FORMAT:
return 11;
default:
return 0;
}
}
}
BOOL
NOTIFY_FUNCTION(
DWORD fdwReason
)
{
if (fdwReason == DLL_PROCESS_ATTACH) {
//
// Sleep when starting up, if the command line is a number.
//
long lSleepTicks = atol(COMMAND_LINE);
if (lSleepTicks > 0) {
Sleep((DWORD)lSleepTicks);
}
}
return TRUE;
}
/*++
Register hooked functions
--*/
HOOK_BEGIN
APIHOOK_ENTRY(KERNEL32.DLL, WinExec)
CALL_NOTIFY_FUNCTION
HOOK_END
IMPLEMENT_SHIM_END