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Re: Stall when uploading to sftp using multi interface

From: Henry Ludemann <>
Date: Thu, 24 Feb 2011 15:17:58 +0800

Hi Daniel,

Daniel Stenberg wrote:
> Just let me clarify to all readers that you are talking about the multi
> socket API here, right?


> Also, as you're talking SFTP you're using libssh2 and then the exact version
> of libssh2 is a vital information.

I was using libssh2 1.2.4; testing using the latest git openssh HEAD
(1.2.8_DEV) still exhibits the problem.

> The key to this issue (so far) seems to be that libcurl doesn't report to
> the app that it should wait for the socket to become writable (or readable)
> properly. That's taken care of by the ssh_perform_getsock() function.

Thanks, that's where I'm focussing my attention at the moment; in that
function conn->waitfor is set to 0 after switching to the SSH_STOP

I've attached a sample file that reproduces the problem; it logins to
localhost using '' and 'key.prv' in the local directory, and
attempts to upload a file to /tmp/test.txt. If you want to try running
it, just adjust the username and add the relevant keys. Also attached
is the output when it runs on my machine (note that recent version of
libssh & libcurl).

I'll continue to attempt to track down the source of the problem.


List admin:

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Received on 2011-02-24