Re: program launcher API for C++?

From:
Joshua Maurice <joshuamaurice@gmail.com>
Newsgroups:
comp.lang.c++.moderated
Date:
Tue, 5 Jun 2012 02:44:00 -0700 (PDT)
Message-ID:
<341a8b1b-3815-4004-90ef-b9967db5ba50@oo8g2000pbc.googlegroups.com>
George Neuner wrote:

There is no way to provide to CreateProcess a list of particular
parent handles to be inherited by the child. Inheritence is
controlled indirectly by the security attributes of the individual
open handles.


[Oh, how off topic we've gone. Hopefully this will be the last.]
{ Agreed. -mod/sk }
As I was saying, there is this obscure barely documented option which
allows you to do just that, for Windows Vista and higher. (This is
also how I got a blue screen when I misused the API.) I would merely
link to the msdn pages, but "obscure barely documented", so here's
some example code. (I reworked it and snipped it for demonstration
purposes - which is my excuse if I got it wrong.) I have tested that
it actually inherits only the specified handles, even if there are
other inheritable handles.

char * memoryBackingAttributeList = 0;
PPROC_THREAD_ATTRIBUTE_LIST attribList;
{
    SIZE_T requiredSize = 0;
    InitializeProcThreadAttributeList(0, 1, 0, & requiredSize);
    memoryBackingAttributeList = new unsigned char[requiredSize];
    attribList =
reinterpret_cast<PPROC_THREAD_ATTRIBUTE_LIST>(memoryBackingAttributeList);
    if ( ! InitializeProcThreadAttributeList(attribList, 1, 0, &
requiredSize))
        FATAL(0, 0);
}

HANDLE handlesList = new HANDLE[numInheritedHandles];
{
    int x = 0;
    handlesList[x++] = inHandle;
    handlesList[x++] = outHandle;
    handlesList[x++] = errHandle;
    if ( ! UpdateProcThreadAttribute(attribList, 0,
PROC_THREAD_ATTRIBUTE_HANDLE_LIST,
        handlesList, sizeof(HANDLE) * numInheritedHandles,
        0, 0))
    { FATAL(0, 0);
    }
}

STARTUPINFOEX startUpInfoEx;
{
    ZeroMemory(&startUpInfoEx, sizeof(STARTUPINFOEX));
    startUpInfoEx.StartupInfo.cb = sizeof(STARTUPINFOEX);
    startUpInfoEx.lpAttributeList = attribList;
    startUpInfoEx.StartupInfo.dwFlags = STARTF_USESTDHANDLES;
    startUpInfoEx.StartupInfo.hStdInput = inHandle;
    startUpInfoEx.StartupInfo.hStdOutput = outHandle;
    startUpInfoEx.StartupInfo.hStdError = errHandle;
}

//...

BOOL const createProcessResult = CreateProcess(
        exeAbsPath,
        processArguments.t,
        0, //security attributes, use default
        0, //thread attributes, use default
        inheritHandlesFlag,
        EXTENDED_STARTUPINFO_PRESENT,
        m_hasCustomEnv ? envWrapper.env : 0, //0 is default env
        m_dir.c_str(), //working dir for new process
        & startUpInfoEx.StartupInfo,
        & processInformation
        );

CreateProcess
http://msdn.microsoft.com/en-us/library/windows/desktop/ms682425%28v=vs.85%29.aspx

STARTUPINFOEX
http://msdn.microsoft.com/en-us/library/windows/desktop/ms686329%28v=vs.85%29.aspx

InitializeProcThreadAttributeList
http://msdn.microsoft.com/en-us/library/windows/desktop/ms683481%28v=vs.85%29.aspx

UpdateProcThreadAttribute
http://msdn.microsoft.com/en-us/library/windows/desktop/ms686880%28v=vs.85%29.aspx

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