Re: 1.7.5: cygwin blocks UAC dialog

[Corinna Vinschen <corinna-cygwin at cygwin dot com>]

On Jun 25 19:29, Shailo Sanyal wrote:
> Hi,
> 
> I am running Cygwin 1.7.5 on Windows 7 (64-bit):
> ------------------------------------
> I4846-vm:intgpune [2] uname -a
> CYGWIN_NT-6.1-WOW64 I4846-vm 1.7.5(0.225/5/3) 2010-04-12 19:07 i686 Cygwin
> ------------------------------------
> 
> If I run an exe from a cygwin tcsh shell the UAC dialog is being
> blocked. I get a "Permission denied." error.
> 
> Here is the manifest file for the exe:
> ------------------------------------
> <?xml version='1.0' encoding='UTF-8' standalone='yes'?>
> <assembly xmlns='urn:schemas-microsoft-com:asm.v1' manifestVersion='1.0'>
> <trustInfo xmlns="urn:schemas-microsoft-com:asm.v3">
>  <security>
>   <requestedPrivileges>
>    <requestedExecutionLevel level="requireAdministrator"/>
>   </requestedPrivileges>
>  </security>
> </trustInfo>
> </assembly>
> ------------------------------------
> 
> This is breaking some of my scripts which call an executable and
> need the UAC dialog to be popped up.
> 
> In a related issue - I also find that Cygwin simply blocks all error
> message popups e.g. for missing DLLs from executables. This makes it
> hard to debug runtime issues.
> 
> Is this a bug with Cygwin? Can it be fixed?

It's not a bug and it can't be fixed.  You can't do this from the
command line.  Child processes are forked and exec'd using the Win32
CreateProcess or CreateProcessAsUser calls.  None of the CreateProcess*
calls has any provisions to interact with UAC.

For the same reason you have to start the entire console session
elevated to run the shell and subsequent applications elevated.

What you could try to do is to start the application via a shim which
calls ShellExecuteEx with the "runas" verb as described here:
http://msdn2.microsoft.com/en-us/library/bb756922.aspx


Corinna

-- 
Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Project Co-Leader          cygwin AT cygwin DOT com
Red Hat

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