Re: channel_select blocks until data received, despite timeout. message 3 of 20)

[libssh.20.awinder@xxxxxxxxxxxxxxx]

Honestly, 0.4.0 release. channels.c (in which the issue occurs) has not 
been updated in regards to this. There is another issue, the reason why 
I used channel_select: on Windows, channel_poll won't get new data 
that's on the wire. This function calls ssh_handle_packets, which calls 
ssh_socket_poll, ssh_poll, poll_rest, which has a call to 
WaitForMultipleObjectsEx(nhandles, handles, FALSE, timeout, TRUE);.

Timeout is set 0 in the call to poll_rest, and WaitForMultipleObjectsEx 
appears to return immediately -- WITHOUT processing new wire data. The 
effect is the channel (nothing, really) receives any new data. The 
workaround: instead of doing channel_poll, I can do a channel_select, 
specify a 1 microsecond timeout, it will get new data and return for me. 
The problem reported occurs if there is no new data. Easy enough to make 
channel_select not loop at all.

-Andrew

Aris Adamantiadis - aris@xxxxxxxxxxxx wrote:
> Hi Andrew,
>
> Which release/version of libssh did you try ? I will check and correct
> this if needed.
>
> Andreas: Could you check/remove the spam filter ? This is not the first
> time it happens.
>
> Thanks,
>
> Aris
>
> libssh.20.awinder@xxxxxxxxxxxxxxx a écrit :
>   
> > channel_select allows a timeout value to be specified. This timeout is
> > used in the select() call, however is not honored because the code
> > requires data to be available on the channel before channel_select returns.
> >
> > channels.c, starting line 2196.
> >
> > First, the channels are polled. If no data is received, the code goes on
> > to block with select() using the given timeout. When select returnes,
> > the code loops back around to check for data on one of the requested
> > channels, and if there is none, continues on to the select() using the
> > given timeout. When select returns, ....
> >
> > When trying to create a bug report: Submission rejected as potential
> > spam (Akismet says content is spam)
> >
> > -Andrew
> > libssh.20.awinder@xxxxxxxxxxxxxxx
> >
> >
> >
> >
> >     
>
>
>
>