Re: anonymous ftp directly to a device

["Daniel F. Montagnese" <dmontagnese mutoh com>]

Kenneth Goodwin wrote:

> well, the device can be a named pipe with a  program reading on the other
> end
> but that can be problematic as some named pipes go crazy when the first
> writer
> closes the pipe from it's end. happens that way on solaris and sco unixware.
> You would think that you could put a reader on one end and have multiple
> writers
> just connect , one after the other using synchronous writes to the single
> reader.
> But most implementations of anmed pipes use the standard PIPE code in the
> kernel
> which expects that when the writers closes it's end, the pipe should be
> shutdown.
> There should be a fcntl or ioctl system call to control this behaviour.
>
> Or it can be a no rewind tape drive. Useful for scientific processing
> where you might want to save a dataset state between processing passes.
>
> personnally I would use the Remote Mag tape facility basd on berkeley RMTD
> They probably setup it up as it is an easier method for standard users to
> understand.
>
> the only way you could do just a PUT filename, is if the filename in use
> isa the same on both systems and this is a dedicated setup for a specific
> purpose.
> You create a symbolic link to the no rewind tape drive in the "server's"
> directory and name
> it "filename" and then when you PUT filename (which is actualyy interpreteed
> as PUT filename filename
> (PUT (local)filename (remote)filename)  you actually put to the tape drive.)
>
> example:
>
> Running scientific analysis program which runs 12 hours per pass and
> generates a database file
> named "bobs-data". My only tape drive is ona  remote systrem only accessible
> via FTP.
> Everyu 12 hours I need to make a clean backup copy of "bobs-data"
>
> On my remote tape drive server machine in my home or FTP directory I create
> a writable symbolic link to  /dev/norewind-tapedrive (whatever
> the local device pathname actually is) and I name that symbolic link
> "bobs-data"
>
> I setup my .netrc on my data cruncher system to auto login to the tape drive
> server.
> I then need a simple shells cript that runs the data computations and then
> does a FTP request to
> the remote tape server machine and does simply a PUT bobs-data command.
> The effect  is that PUT sends my local datafile as a append to the remote
> tape drive.
> Just have to change the tape periodically prior to running out.
>
> ++> -----Original Message-----
> ++> From: enigma-list-admin redhat com
> ++> [mailto:enigma-list-admin redhat com]On Behalf Of Gordon Messmer
> ++> Sent: Saturday, November 16, 2002 3:09 PM
> ++> To: enigma-list redhat com
> ++> Subject: Re: anonymous ftp directly to a device
> ++>
> ++>
> ++> On Fri, 2002-11-15 at 15:40, Daniel F. Montagnese wrote:
> ++> > Gordon Messmer wrote:
> ++> > > On Fri, 2002-11-15 at 08:17, Daniel F. Montagnese wrote:
> ++> > > >
> ++> > > > at the command line.  Any file "put" in the directory
> ++> would be written
> ++> > > > to the device and the results of "ls" would still be
> ++> what it was before.
> ++> > > > The "put" file would not be added to the "ls" list.
> ++> I wonder how that
> ++> > > > was done.   ????????
> ++> > >
> ++> > > Simple.  Make the directory a+wx,a-r (mode 333).
> ++> Anyone can write files
> ++> > > to the directory, but no one (except root) can get a
> ++> list of the files
> ++> > > therein.  You just have to configure the FTP server to
> ++> allow uploads to
> ++> > > that directory, by default uploads should be disallowed.
> ++> >
> ++> > Thank you for the response.  I still wonder how the file
> ++> is written directly
> ++> > to the device listed in the server ftp directory and how
> ++> > the login is accomplished by only "ftp id_address"  at
> ++> the client command
> ++> > line not followed by "user me" and "password mine".
> ++>
> ++> I was a bit confused by the device thing....  If you write
> ++> directly to a
> ++> device (as you might write to a tape...), then of course the files
> ++> uploaded wouldn't show up in "ls"...  They'd be streams on
> ++> the device.
> ++> And unless the device is a non-rewinding streaming device, each file
> ++> will over-write the last.  It doesn't seem like very useful
> ++> behavior at
> ++> all.
> ++>
> ++> If you want to allow anonymous FTP, just install the
> ++> anonftp package.
> ++>
> ++>
> ++>
> ++>
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> ++>
>
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Thank you for the response.  I learned alot of things that will surely prove
useful.

There is new information.  I just found out that the ftp source code was
modified to accomplish the above-described
behavior.

The system is an embedded Linux system that runs on a pci card inside of a
large format printer.   The only listing in /var/lib/ftp is a link to a
device in /dev that reads and writes the pci interface.  Any connection to frp
is accomplished with no authentication and all "put" files
are written to the device.

Excuse me for putting you to all the trouble.    The new information was
unexpected.

All the best,
Daniel F. Montagnese