This distribution is somewhat obsolete. This functionality is
bundled with the Unix server.
-----------------------------
In this distribution is a small C daemon called g2fd.c. This is third
incarnation of a Gopher to FTP gateway. Running this daemon on a UNIX
box gives folks running gopher clients access to all that good stuff
available out there for anonymous ftp.
Previous versions were prototypes written in Perl. The prototype got
so popular that gopher folks going out to get stuff via ftp were
swamping the unix box that was running the gopher-to-ftp daemon. This
version is much more efficient and has reasonably portable (ha!) load
limiting code. This version has no logging code... we'll get round to
that by and by.
The principle is this: the gopher client connects to the g2fd daemon
and tells it what the name of the ftp site is, (and perhaps what file
it wishes to retrieve from there). The daemon connects to the remote
host, retrieves a directory listing (or file) via anonymous ftp, and
returns it to the gopher client. Of course all this happens without
any new knowledge by the gopher client.
The daemon assumes a nice healthy unixy ftp server at the ftp end...
that is to say it is probably not going to work with funky IBM or
TOPS-20 ftp implementations. This is left as an exercise for the
hacker... er... reader.
The daemon is designed to be run by inetd as a TCP daemon.
The easiest way to explain how to set it up and how it works
is to use an example.
Let us assume that we want to run a gopher to FTP gateway on a machine
called hell.micro.umn.edu at port 70. If you already have a regular
gopher server running at port 70 (the sanctioned gopher port), on
hell.micro.umn.edu you can run g2fd at some other high numbered
unreserved port; try something over 3000?
1. Edit the parameters (marked lines right after the #includes).
in g2fd.c for your
local configuration; in this case change the marked lines as follows:
/*==============Local parameters to be edited in===============*/
#define LOCALHOST "hell.micro.umn.edu" /* This host's domain name */
#define LOCALPORT 70 /* This daemon's port */
#define MAXLOAD 8.0 /* For load limit if > 1 */
#define FTP "/usr/ucb/ftp" /* To invoke ftp */
#define UPTIME "/usr/ucb/uptime" /* To check loadavg. Ick. */
#define LIST "/tmp/gftpL+" /* Temp list file prefix */
#define DATA "/tmp/gftpD+" /* Temp data file prefix */
/*=============================================================*/
The MAXLOAD parameter specifies how high the load average on the
host can get before the daemon will refuse new connections.
You might also check to find the whereabouts of ftp and uptime
(use "whereis ftp" or poke around) and specify the full pathname.
The LIST and DATA strings specify where the daemon is to stash
temporary files; leave the + on the end. In this example, temp
files will be placed in /tmp.
2. Compile the daemon:
make g2fd
3. Become root and place the g2fd file someplace nice (like
/usr/local/bin or /usr/etc or wherever you place stuff like this);
assume we put it in /usr/local/bin. Make it owned by root and
executable:
chown root g2fd
chmod 755 g2fd
4. Update /etc/services by adding the following line to the
/etc/services file (note it's a tab between g2fd and 70):
g2fd 70/tcp
For SUNs running yp, you'll also want to do a make services:
cd /var/yp
make services
5. Now update /etc/inetd.conf or /etc/servers:
For SunOS 4.0 or BSD 4.3 systems add the following line to
/etc/inetd.conf:
g2fd stream tcp nowait root /usr/local/bin/g2fd %A
For Ultrix systems, (which we haven't tested under!)
add the following line to /etc/inetd.conf:
g2fd stream tcp nowait /usr/local/bin/g2fd
For A/UX or SunOS 3.5 add a line to /etc/servers:
g2fd tcp /usr/local/bin/g2fd
Note tabs between fields.
6. Kill and restart the inetd daemon whatever the prescribed way
to do that on your machine.
7. You can confirm that g2fd is running now at port 70 by
telneting to hell.micro.umn.edu at port 70. Test it out by
typing
boombox.micro.umn.edu@/pub/
This funky path means "return the directory listing from the
/pub/ directory from boombox.micro.umn.edu."
It should respond by returning the /pub/ ftp directory at
boombox.micro.umn.edu.
8. Now make some links from a regular gopher server to the g2fd
service. On a unix server, a link could look like this (on a
Mac server, do the functional equivalent using Gopher's Helper):
Name=boombox: Home of POPmail and Gopher Central.
Type=1
Port=70
Path=boombox.micro.umn.edu@/pub/
Host=hell.micro.umn.edu
And you're all set.
What happens is that the user sees the full Name (as always), say
"boombox: Home of POPmail and Gopher Central". It would appear as
a directory (or folder icon on a Mac). If selected (double-clicked
on a Mac), the client would open a connection to hell.micro.umn.edu
at port 70. The g2fd daemon would accept. The client would
then send it the selector string "boombox.micro.umn.edu@/pub/". The
daemon would interpret this as "Go out to boombox.micro.umn.edu
via anonymous ftp and get a listing of the pub directory." The
daemon would return this listing to the client in nice gopher
format. And everything else happens by magic as you would expect.
To the client it looks just like any other gopher-type directory. The
script does assume that files ending in .hqx are BinHex files and gives
them the type 4. It also makes rash assumptions about the plethora of
DOS binary files (.zip et. al.), and maps them all to a type 5. The
client can decide what to do with them based on the .xxx extension that
most seem to carry. Finally, it gives tar and Z files a filetype of 9.
And 9 is a new gopher item type (actually the only one we've allocated
since we set up standards for the protocol. All other files are given
normal type 0: that is text.
If your client is capable of handling binary types then it can allow
type 5 and/or type 9 in directory listings. It should be prepared to
do things based just on the extensions (.xxx) of the files that the
user requests. In particular, it will need to just read from the
connection until the server closes the connection when sending a binary
file. So there will be no concluding period, and obviously lines are
meaningless.
WATCH OUT: The script has no way of knowing for sure that a file at an
ftp site is binary (other than educated guesses based on the suffix of
the filename), so when it presents gopherized listings, it must show
these files too. When a client attempts to retrieve a file, the script
can peek into the file and make a much more educated guess as to
whether it contains text. So it should prevent a client from
transferring totally gonzo binary.
It would probably be wise to place caution ReadMe files out there for
the users. Also, if possible good gopher administrators would place
the link all the way inside the "pub" or whatever directory at the
server end. We really don't want users fumbling around inside the bin
or etc directories and attempting to suck down binary files.
Once more: the binary question is still open and we need to resolve
that one yet.
All credit for this great and simple idea should go to Craig Rice
(
[email protected]). Thanks Craig.
The previous Perl script was much enhanced by John Ladwig.
Suggestions or bug reports for this daemon are welcome...
The capabilities of this daemon will probably get rolled into
the main gopher daemon in the next release.
FXA.
