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Date: Mon, 16 Apr 2007 11:57:57 +0200
From: Corinna Vinschen <corinna-cygwin AT cygwin DOT com>
To: cygwin AT cygwin DOT com
Subject: Re: Unable to open /dev/mem: permission denied
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On Apr 15 03:15, Brian Dessent wrote:
> Jamie Mortimore wrote:
> 
> > Unable to open /dev/mem: Permission denied
> > 
> > I have set up a root user (in /etc/passwd) and am running the program
> > as root but this doesn't solve the problem. Any help much appreciated.
> 
> Having a user named 'root' in passwd is irrelevant.  What matters is
> whether you are logged in to Windows with a user account that has
> Administrator privileges.  Is that what you mean by "running the program
> as root"?
> 
> To be clear, it doesn't matter at all what you name the user or what you
> put in /etc/passwd or /etc/group, what matters is whether Windows
> considers the user to have admin privileges, as the return value of
> open("/dev/mem") is just a direct translation of the result of calling
> the NT function to open \device\physicalmemory, so it's up to Windows
> whether this fails or succeeds, not anything in Cygwin.

Funny(*) sidenote:  Accessing \device\physicalmemory from privileged
user mode processes works only on NT4, W2K and XP.  Starting with 2K3,
access to physical memory has been restricted to work only in kernel
mode.


Corinna


(*) No, not really.


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

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