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Re: Descriptor passing between process

On Thu, Jan 24, 2002 at 04:38:40PM +0100, Corinna Vinschen wrote:
> On Thu, Jan 24, 2002 at 04:45:13PM +0300, Egor Duda wrote:
> > Hi!
> > 
> > Thursday, 24 January, 2002 Corinna Vinschen wrote:
> > 
> > CV> On Thu, Jan 24, 2002 at 04:14:20PM +0300, Egor Duda wrote:
> > >> CV> It's part of the API since 1.3.8-1.
> > >> 
> > >> Hmm. What change are you referring to? I don't see anything like this
> > >> in the ChangeLog.
> > 
> > CV> 2002-01-19  Mark Bradshaw  <>
> > 
> > CV>         * cygwin.din: Add recvmsg and sendmsg.
> > CV>         * Add cygwin_recvmsg and cygwin_sendmsg.
> > CV>         * /usr/include/sys/socket.h: Add recvmsg and sendmsg.
> > 
> > yes, but if i understand things correctly, Christophe was talking
> > about passing file descriptors between processes by means of AF_UNIX
> > sockets. btw, "Subject:" implies this :).
> > 
> > this is done on unices via msg_control (or msg_accrights) field in msg
> > structure. and unices ensure that the process which receives the
> > message using recvmsg can use the descriptor for all kinds of file
> > operations. in the case of cygwin, the receiver may get the value 3 in
> > message packet, but won't be able to use it in "read (3, buf, sizeof (buf))"
> Ouch.  I didn't read your message correctly before sending the
> reply to Christophe's mail.

More ouch!  I just read a detailed description of the descriptor
passing magic via AF_LOCAL sockets in U*X systems. I see now that
I didn't even know what you were talking about.

It *could* be implemented.  

First we would have to implement the control message passing at all and
when it's available we could perhaps even implement descriptor passing
using the DuplicateHandle() function.



Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Developer                      
Red Hat, Inc.

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