[344] in linux-net channel archive
Does NcFTP tickle a race?
daemon@ATHENA.MIT.EDU (Steven J. Madsen)
Fri May 19 14:12:18 1995
From: "Steven J. Madsen" <steve@erinet.com>
To: linux-net@vger.rutgers.edu
Date: Fri, 19 May 1995 13:01:04 -0400 (EDT)
I'm running NcFTP 2.0.5 on Linux 1.2.8, w/out the 1.3 networking
code. My net connection is a 28.8 PPP link, which has otherwise worked just
fine.
It seems that either NcFTP has a bug, or it tickles a race condition
in the old networking code. I've contacted the author, and he hasn't been
terribly helpful, but I'm sure he's quite busy, so I thought I'd try here.
The symptoms are simple. If I try to put a file with NcFTP, it
sends out the first 32k (seen by the stat bar), and my modem goes to work
sending out the packets. NcFTP then starts to time out, since the second
32k can't be sent until the first 32k is gone. Eventually, it times out and
aborts the transfer, and only the first 32k has been queued up or sent.
/usr/bin/ftp works perfectly, so that's what I've been using for sending out
files.
Here's the interesting part. Since I'm on a 28.8 link, and it takes
about one minute for NcFTP to give up, I can usually get between 150k and
200k of data actually sent. The modem is constantly busy sending, but it
appears to send the *same* 32k block over and over again. Examining the
destination file shows that it does contain more than 32k of data, but it
seems to be the same data. For example, sending a tar file, I only get the
filenames for about the first 32k, after which it gets confused, even though
the file is 150k or larger.
Since 1.3 is probably coming quite soon, should I just abandon the
1.2.x networking code and start working with the 1.3 code, or is this more
likely a problem with NcFTP?
--
Steve Madsen <steve@erinet.com>
Finger smadsen@cs.muohio.edu for PGP public key
