Privilege(s) needed to run top command

Corinna Vinschen
Tue Mar 12 20:28:00 GMT 2019

On Mar 12 18:39, Corinna Vinschen wrote:
> On Mar 12 18:13, Corinna Vinschen wrote:
> > On Mar 12 10:00, jwang wrote:
> > > Sir,
> > 
> > Nope.
> > 
> > > I download, this morning:
> > > 3132 -rw-r--r--  1 james None 3207004 Mar 12 10:50 cygwin-20190312.tar.xz
> > > 
> > > tar -xvf cygwin-20190312.tar.xz
> > 
> > Where to?  You have to install cygwin1.dll in place of the other
> > cygwin1.dll while having stopped all Cygwin processes.  Just unpacking
> > with tar won't do anything useful.
> > 
> > > then I did: 
> > > 
> > > usr/bin/ps -W|grep httpd
> > 
> > This is really not helpful as far as bug reports go.  Drop the
> > grep, drop the -W.  Just call `ps -e' or `procps -e' or `top'
> > and see what's visible.  Do you see all CYgwin processes?  If so, fine.
> > If not, please report details.  Just don't expect top's load average
> > values to make any sense if you're running under a non-privileged
> > user account.  They will be always 0.
> Btw., `ps -W' only shows non-Cygwin processes visible inside the
> current user session.  This session isolation has been introduced with
> Windows 2003 and since Vista even the console interactive session is
> running in its own session distinct from session 0.
> Task Manager doesn't suffer this problem, but it's not clear to me why.
> Perhaps it connects to a broker service which gives task manager access
> to all processes.

This was complete nonsense.

Actually, the problem was entirely in Cygwin's ps.exe, and it's a
long-standing problem at that.

While the Cygwin DLL collected the complete process list for ps, ps then
didn't print any process it failed to call OpenProcess on.  These are a
*lot* of processes and the result looked a lot like the list of
processes in or connected to the current session.

The reason for this behaviour was that the image path of a process could
only be fetched when opening the process.  Today I found new
functionality since Vista which allows to fetch the image path without
having to open the process, so `ps -W' will print all processes again,
just as in the good old XP times :}

Please try the latest snapshot from

Make sure to use ps.exe from that snapshot since this time the ps
executable is affected, not the Cygwin DLL itself.


Corinna Vinschen
Cygwin Maintainer
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 833 bytes
Desc: not available
URL: <>

More information about the Cygwin mailing list