Re: zeroseek and qmail

On Tue, Aug 27, 2002 at 02:39:23PM -0400, Russell Nelson allegedly wrote:
> Jos Backus writes:
>  > On Tue, Aug 27, 2002 at 10:36:43AM -0600, Charles Cazabon wrote:
>  > > As you say, he only talks about the seekability in terms of the fd provided to
>  > > qmail-local, not /by/ qmail-local to other programs.
>  > > 
>  > > The only obvious way I can think of to keep the fd provided to programs
>  > > seekable under zeroseek would involve copying the message to a temporary file
>  > > and providing an fd to that; this could be done inside qmail-local when it
>  > > invokes a command delivery.
>  > 
>  > That sounds kind of messy to me.
> 
> Why?  qmail-local would already need to do this if it had a non-tail
> program delivery.  How else do you preserve the semantics of the
> program delivery exiting with a 100 (permanent failure) exit code?

Eh? Which semantics need to be preserved exactly that relate to a
seekable stdin or the need to create a temp file?

It's conceivable in zeroseek-land that qmail-local is given a
read-only fd of the zeroseek file (and message location information**)
and it creates a read/write pipeline to each program delivery. No temp
file needed, no quota issues, no memory issues.


Regards.


** Which creates a risk in terms of exposing content of other messages
   if qmail-local is buggy, but I don't know how that risk can be
   completely avoided in zeroseek-land.