On Fri, Oct 26, 2001 at 05:49:08PM +0300, Maxim Sobolev wrote:
> Ian Dowse wrote:
> >
> > In message <[EMAIL PROTECTED]>, Maxim Sobolev writ
> > es:
> > > Nautilus from working properly. The problem disappeared when I've replaced
> > > writev(2) call with appropriate loop based around ordinary write(2). Perhaps
> > > this should be investigated and the real source of the problem fixed instead,
> > > but I do not have a time for this right now. For those who interested I'm
> > > ready to provide a step-by step instruction on how to reproduce the bug.
> >
> > Hi,
> >
> > If you have the details handy, a post to -hackers is likely to be
> > quite constructive at getting the problem analysed and resolved.
>
> Ok, details are below.
>
> GNOME oaf is a CORBA-based RPC framework. It uses UNIX
> domain sockets to communicate between client application and
> oafd daemon that serves requests. Usually the communication
> looks like the following:
>
> 1. Client connects to the oafd daemon via domain socket and
> sends marshalled RPC request.
> 2. The daemon reads request, demarshalls it and executes
> either internally or by invoking external program/shared
> library.
> 3. The daemon marshalls result of the call and passes it
> back to the client via the same socket.
>
> On the step 3, when marshalling results of the call, daemon
> creates a large collection of small buffers (usually 5-10
> bytes long each) arranged as array of struct iovec and then
> sends this whole buffer to the client using writev(2) call.
> In my particular case there were some 2,800 entries in the
> buffer and when the daemon tried to send it to the client
> writev(2) was returning -1 and setting errno to be EINVAL,
> which confused the server and the client causing RPC to
> fail.
2800 entries? Well, from the writev(2) manual page:
In addition, writev() may return one of the following errors:
...
[EINVAL] Iovcnt was less than or equal to 0, or greater than
UIO_MAXIOV.
And at least on -stable, UIO_MAXIOV is defined as 1024..
G'luck,
Peter
--
Thit sentence is not self-referential because "thit" is not a word.
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