freebsd-skq/gnu/libexec/uucp/doc/uucp.texi

\input texinfo   @c -*-texinfo-*-
@c %**start of header
@setfilename uucp.info
@settitle Taylor UUCP
@setchapternewpage odd
@c %**end of header

@iftex
@finalout
@end iftex

@ignore
---------------------------------------------------------------------->
Franc,ois Pinard says:

Hi, Ian!  This is the promised merging of the current documents from
Taylor UUCP 1.01, plus the patches to documentation you sent to me, into
a taylor.texi file.  Many things remain to do, among which:

- merging in the Taylor UUCP program man pages.
----------------------------------------------------------------------<
@end ignore

@ifinfo
This file documents Taylor UUCP, version 1.05.

Copyright @copyright{} 1992, 1993, 1994 Ian Lance Taylor

Permission is granted to make and distribute verbatim copies of this
manual provided the copyright notice and this permission notice are
preserved on all copies.

@ignore 
Permission is granted to process this file through TeX and print the
results, provided the printed document carries a copying permission
notice identical to this one except for the removal of this paragraph
(this paragraph not being relevant to the printed manual).

@end ignore
Permission is granted to copy and distribute modified versions of this
manual under the conditions for verbatim copying, provided also that the
section entitled ``Copying'' are included exactly as in the original, and
provided that the entire resulting derived work is distributed under the
terms of a permission notice identical to this one.

Permission is granted to copy and distribute translations of this manual
into another language, under the above conditions for modified versions,
except that the section entitled ``Copying'' may be included in a
translation approved by the author instead of in the original English.
@end ifinfo

@titlepage
@title Taylor UUCP
@subtitle Version 1.05
@author Ian Lance Taylor @code{<ian@@airs.com>}

@page
@vskip 0pt plus 1filll
Copyright @copyright{} 1992, 1993, 1994 Ian Lance Taylor

Published by Ian Lance Taylor @code{<ian@@airs.com>}.

Permission is granted to make and distribute verbatim copies of this
manual provided the copyright notice and this permission notice are
preserved on all copies.

Permission is granted to copy and distribute modified versions of this
manual under the conditions for verbatim copying, provided also that the
section entitled ``Copying'' are included exactly as in the original, and
provided that the entire resulting derived work is distributed under the
terms of a permission notice identical to this one.

Permission is granted to copy and distribute translations of this manual
into another language, under the above conditions for modified versions,
except that the section entitled ``Copying'' may be included in a
translation approved by the author instead of in the original English.
@end titlepage

@node Top, Copying, (dir), (dir)
@top Taylor UUCP 1.05

This is the documentation for the Taylor UUCP package, version 1.05.
The programs were written by Ian Lance Taylor.  The author can be
reached at @code{<ian@@airs.com>}, or @samp{c/o Cygnus Support, Building
200, 1 Kendall Square, Cambridge, MA, 02139, USA}.

There is a mailing list for discussion of the package.  To join (or get
off) the list, send mail to
@code{<taylor-uucp-request@@gnu.ai.mit.edu>}.  Mail to this address is
answered by a person, not a program.  When joining the list, please give
the address at which you wish to receive mail; do not rely on the
message headers.  To send a message to the list, send it to
@code{<taylor-uucp@@gnu.ai.mit.edu>}.

Jeff Ross has volunteered to maintain patches for UUCP releases.  They
may be obtained via anonymous FTP from ftp.fdu.edu, in the directory
pub/taylor-uucp.

@menu
* Copying::                     Taylor UUCP copying conditions
* Introduction::                Introduction to Taylor UUCP
* Overall Installation::        Taylor UUCP installation
* Configuration Files::         Taylor UUCP configuration files
* Protocols::                   UUCP protocol internals
* Hacking::                     Hacking Taylor UUCP
* Acknowledgements::            Acknowledgements

* Index (concepts)::            Concept index
* Index (configuration file)::  Index to new configuration files

 --- The Detailed Node Listing ---

Taylor UUCP Overall Installation

* Configuration::               Configuring Taylor UUCP
* Compilation::                 Compiling Taylor UUCP
* Testing::                     Testing Taylor UUCP
* Installation::                Installing Taylor UUCP
* TCP::                         TCP together with Taylor UUCP

Installing Taylor UUCP

* Running uucico::              Running uucico
* Using UUCP for mail and news::  Using UUCP for mail and news.
* Trimming UUCP Log Files::     Trimming UUCP Log Files

Using UUCP for mail and news.

* Sending mail or news::        Sending mail or news via UUCP
* Receiving mail or news::      Receiving mail or news via UUCP

Taylor UUCP Configuration Files

* Configuration File Format::   Configuration file format
* Configuration File Overview::  Configuration File Overview
* Configuration Examples::      Examples of configuration files
* Time Strings::                How to write time strings
* Chat Scripts::                How to write chat scripts
* config File::                 The main configuration file
* sys File::                    The system configuration file
* port File::                   The port configuration files
* dial File::                   The dialer configuration files
* Security::                    Security issues

Examples of Configuration Files

* config File Examples::        Examples of the main configuration file
* Leaf Example::                Call a single remote site
* Gateway Example::             The gateway for several local systems

The Main Configuration File

* Miscellaneous (config)::      Miscellaneous config file commands
* Configuration File Names::    Using different configuration files
* Log File Names::              Using different log files
* Debugging Levels::            Debugging levels

The System Configuration File

* Defaults and Alternates::     Using defaults and alternates
* Naming the System::           Naming the system
* Calling Out::                 Calling out
* Accepting a Call::            Accepting a call
* Protocol Selection::          Protocol selection
* File Transfer Control::       File transfer control
* Miscellaneous (sys)::         Miscellaneous sys file commands
* Default sys File Values::     Default values

Calling Out

* When to Call::                When to call
* Placing the Call::            Placing the call
* Logging In::                  Logging in

Hacking Taylor UUCP

* System Dependence::           System Dependence
* Naming Conventions::          Naming Conventions
* Patches::                     Patches
@end menu

@node Copying, Introduction, Top, Top
@unnumbered Taylor UUCP Copying Conditions

This package is covered by the GNU Public License.  See the file
@file{COPYING} for details.  If you would like to do something with this
package that you feel is reasonable, but you feel is prohibited by the
license, contact me to see if we can work it out.

Here is some propaganda from the Free Software Foundation.  If you find
this stuff offensive or annoying, remember that you probably did not
spend any money to get this code.  I did not write this code to make
life easier for developers of UUCP packages, I wrote it to help end
users, and I believe that these are the most appropriate conditions for
distribution.

All the programs, scripts and documents relating to Taylor UUCP are
@dfn{free}; this means that everyone is free to use them and free to
redistribute them on a free basis.  The Taylor UUCP-related programs are
not in the public domain; they are copyrighted and there are
restrictions on their distribution, but these restrictions are designed
to permit everything that a good cooperating citizen would want to do.
What is not allowed is to try to prevent others from further sharing any
version of these programs that they might get from you.

Specifically, we want to make sure that you have the right to give away
copies of the programs that relate to Taylor UUCP, that you receive
source code or else can get it if you want it, that you can change these
programs or use pieces of them in new free programs, and that you know
you can do these things.

To make sure that everyone has such rights, we have to forbid you to
deprive anyone else of these rights.  For example, if you distribute
copies of the Taylor UUCP related programs, you must give the recipients
all the rights that you have.  You must make sure that they, too,
receive or can get the source code.  And you must tell them their
rights.

Also, for our own protection, we must make certain that everyone finds
out that there is no warranty for the programs that relate to Taylor
UUCP.  If these programs are modified by someone else and passed on, we
want their recipients to know that what they have is not what we
distributed, so that any problems introduced by others will not reflect
on our reputation.

The precise conditions of the licenses for the programs currently being
distributed that relate to Taylor UUCP are found in the General Public
Licenses that accompany them.

@node Introduction, Overall Installation, Copying, Top
@chapter Introduction to Taylor UUCP

General introductions to UUCP are available, and perhaps one day I will
write one.  In the meantime, here is a very brief one that concentrates
on the programs provided by Taylor UUCP.

Taylor UUCP is a complete UUCP package.  It is covered by the GNU Public
License, which means that the source code is always available.  It is
composed of several programs; most of the names of these programs are
based on earlier UUCP packages.

@table @code

@item uucp

The @code{uucp} program is used to copy file between systems.  It is
similar to the standard Unix @code{cp} program, except that you can
refer to a file on a remote system by using @samp{system!} before the
file name.  For example, to copy the file @file{notes.txt} to the system
@samp{airs}, you would say @samp{uucp notes.txt airs!~/notes.txt}.  In
this example @samp{~} is used to name the UUCP public directory on
@samp{airs}.

@item uux

The @code{uux} program is used to request the execution of a program on
a remote system.  This is how mail and news are transferred over UUCP.
As with @code{uucp}, programs and files on remote systems may be named
by using @samp{system!}.  For example, to run the @code{rnews} program
on @samp{airs} passing it standard input, you would say @samp{uux -
airs!rnews}.  The @samp{-} means to read standard input and set things
up such that when @code{rnews} runs on @samp{airs} it will receive the
same standard input.

@end table

Neither @code{uucp} nor @code{uux} actually do any work immediately.
Instead, they queue up requests for later processing.  They then start a
daemon process which processes the requests and calls up the appropriate
systems.  Normally the system will also start the daemon periodically to
check if there is any work to be done.  The advantage of this approach
is that it all happens automatically.  You don't have to sit around
waiting for the files to be transferred.  The disadvantage is that if
anything goes wrong it might be a while before anybody notices.

@table @code

@item uustat

The @code{uustat} program does many things.  By default it will simply
list all the jobs you have queued with @code{uucp} or @code{uux} that
have not yet been processed.  You can use @code{uustat} to remove any of
your jobs from the queue.  You can also it use it to show the status of
the UUCP system in various ways, such as showing the connection status
of all the remote systems your system knows about.  The system
administrator can use @code{uustat} to automatically discard old jobs
while sending mail to the user who requested them.

@item uuname

The @code{uuname} program by default lists all the remote systems your
system knows about.  You can also use it to get the name of your local
system.  It is mostly useful for shell scripts.

@item uulog

The @code{uulog} program can be used to display entries in the UUCP log
file.  It can select the entries for a particular system or a particular
user.  You can use it to see what has happened to your queued jobs in
the past.

@item uuto
@item uupick

@code{uuto} is a simple shell script interface to @code{uucp}.  It will
transfer a file, or the contents of a directory, to a remote system, and
notify a particular user on the remote system when it arrives.  The
remote user can then retrieve the file(s) with @code{uupick}.

@item cu

The @code{cu} program can be used to call up another system and
communicate with it as though you were directly connected.  It can also
do simple file transfers, though it does not provide any error checking.

@end table

These eight programs just described, @code{uucp}, @code{uux},
@code{uuto}, @code{uupick}, @code{uustat}, @code{uuname}, @code{uulog},
and @code{cu} are the user programs provided by Taylor UUCP@.
@code{uucp}, @code{uux}, and @code{uuto} add requests to the work queue,
@code{uupick} extracts files from the UUCP public directory,
@code{uustat} examines the work queue, @code{uuname} examines the
configuration files, @code{uulog} examines the log files, and @code{cu}
just uses the UUCP configuration files.

The real work is actually done by two daemon processes, which are
normally run automatically rather than by a user.

@table @code

@item uucico

The @code{uucico} daemon is the program which actually calls the remote
system and transfers files and requests.  @code{uucico} is normally
started automatically by @code{uucp} and @code{uux}.  Most systems will
also start it periodically to make sure that all work requests are
handled.  @code{uucico} checks the queue to see what work needs to be
done, and then calls the appropriate systems.  If the call fails,
perhaps because the phone line is busy, @code{uucico} leaves the
requests in the queue and goes on to the next system to call.  It is
also possible to force @code{uucico} to call a remote system even if
there is no work to be done for it, so that it can pick up any work that
may be queued up remotely.

@need 1000
@item uuxqt

The @code{uuxqt} daemon processes execution requests made by the
@code{uux} program on remote systems.  It also processes requests made
on the local system which require files from a remote system.  It is
normally started by @code{uucico}.

@end table

Suppose you, on the system @samp{bantam}, want to copy a file to the
system @samp{airs}.  You would run the @code{uucp} command locally, with
a command like @samp{uucp notes.txt airs!~/notes.txt}.  This would queue
up a request on @samp{bantam} for @samp{airs}, and would then start the
@code{uucico} daemon.  @code{uucico} would see that there was a request
for @samp{airs} and attempt to call it.  When the call succeeded,
another copy of @code{uucico} would be started on @samp{airs}.  The two
copies of @code{uucico} would tell each other what they had to do and
transfer the file from @samp{bantam} to @samp{airs}.  When the file
transfer was complete the @code{uucico} on @samp{airs} would move it
into the UUCP public directory.

UUCP is often used to transfer mail.  This is normally done
automatically by mailer programs.  When @samp{bantam} has a mail message
to send to @samp{ian} at @samp{airs}, it executes @samp{uux - airs!rmail
ian} and writes the mail message to the @code{uux} process as standard
input.  The @code{uux} program, running on @samp{bantam}, will read the
standard input and store it, as well as the @code{rmail} request itself,
on the work queue for @samp{airs}.  @code{uux} will then start the
@code{uucico} daemon.  The @code{uucico} daemon will call up
@samp{airs}, just as in the @code{uucp} example, and transfer the work
request and the mail message.  The @code{uucico} daemon on @samp{airs}
will put the files on a local work queue.  When the communication
session is over, the @code{uucico} daemon on @samp{airs} will start the
@code{uuxqt} daemon.  @code{uuxqt} will see the request to run, and will
run @samp{rmail ian} with the mail message as standard input.  The
@code{rmail} program, which is not part of the UUCP package, is then
responsible for either putting the message in the right mailbox on
@samp{airs} or forwarding the message on to another system.

Taylor UUCP comes with a few other programs that are useful when
installing and configuring UUCP.

@table @code

@item uuchk

The @code{uuchk} program reads the UUCP configuration files and displays
a rather lengthy description of what it finds.  This is useful when
configuring UUCP to make certain that the UUCP package will do what you
expect it to do.

@item uuconv

The @code{uuconv} program can be used to convert UUCP configuration
files from one format to another.  This can be useful for administrators
converting from an older UUCP.  Taylor UUCP is able to read and use old
configuration file formats, but some new features can not be selected
using the old formats.

@item uusched

The @code{uusched} script is just provided for compatibility with older
UUCP releases.  It starts @code{uucico} to call, one at a time, all the
systems for which work has been queued.

@item tstuu

The @code{tstuu} program is a test harness for the UUCP package; it can
help check that the package has been configured and compiled correctly.
However, it uses pseudo-terminals, which means that it is less portable
than the rest of the package.  If it works, it can be useful when
initially installing Taylor UUCP.

@end table

@node Overall Installation, Configuration Files, Introduction, Top
@chapter Taylor UUCP Overall Installation

These are the installation instructions for the Taylor UUCP package.

@menu
* Configuration::               Configuring Taylor UUCP
* Compilation::                 Compiling Taylor UUCP
* Testing::                     Testing Taylor UUCP
* Installation::                Installing Taylor UUCP
* TCP::                         TCP together with Taylor UUCP
@end menu

@node Configuration, Compilation, Overall Installation, Overall Installation
@section Configuring Taylor UUCP

You will have to decide what types of configuration files you want to
use.  This package supports a new sort of configuration file; see
@ref{Configuration Files}.  It also supports V2 configuration files
(@file{L.sys}, @file{L-devices}, etc.) and HDB configuration files
(@file{Systems}, @file{Devices}, etc.).  No documentation is provided
for V2 or HDB configuration files.  All types of configuration files can
be used at once, if you are so inclined.  Currently using just V2
configuration files is not really possible, because there is no way to
specify a dialer (there are no built in dialers, and the program does
not know how to read @file{acucap} or @file{modemcap}); however, V2
configuration files can be used with a new style dial file (@pxref{dial
File}), or with a HDB @file{Dialers} file.

Use of HDB configuration files has two known bugs.  A blank line in the
middle of an entry in the @file{Permissions} file will not be ignored as
it should be.  Dialer programs, as found in some versions of HDB, are
not recognized directly.  If you must use a dialer program, rather than
an entry in @file{Devices}, you must use the @code{chat-program} command
in a new style dial file; see @ref{dial File}.  You will have to invoke
the dialer program via a shell script or another program, since an exit
code of 0 is required to recognize success; the @code{dialHDB} program
in the @file{contrib} directory may be used for this purpose.

The @code{uuconv} program can be used to convert from V2 or HDB
configuration files to the new style (it can also do the reverse
translation, if you are so inclined).  It will not do all of the work,
and the results should be carefully checked, but it can be quite useful.

If you are installing a new system, you will, of course, have to write
the configuration files; see @ref{Configuration Files}.

You must also decide what sort of spool directory you want to use.  If
you will be using only these programs for UUCP, I recommend
@samp{SPOOLDIR_TAYLOR}; otherwise select the spool directory
corresponding to your existing UUCP package.  The details of the spool
directory choices are described at somewhat tedious length in
@file{unix/spool.c}.

@node Compilation, Testing, Configuration, Overall Installation
@section Compiling Taylor UUCP

@enumerate

@item
Take a look at the top of @file{Makefile.in} and set the appropriate
values for your system.  These control where the programs are installed
and which user on the system owns them (normally they will be owned by a
special user @code{uucp} rather than a real person; they should probably
not be owned by @code{root}).

@item
Run the shell script @code{configure}.  This script was generated using
the @code{autoconf} program written by David MacKenzie of the Free
Software Foundation.  It takes a while to run.  It will generate the
file @file{config.h} based on @file{config.h.in}, and, for each source
code directory, will generate @file{Makefile} based on
@file{Makefile.in}.

You can pass certain arguments to @code{configure} in the environment.
Because @code{configure} will compile little test programs to see what
is available on your system, you must tell it how to run your compiler.
It recognizes the following environment variables:

@table @samp
@item CC
The C compiler.  If this is not set, then if @code{configure} can find
@samp{gcc} it will use it, otherwise it will use @samp{cc}.
@item CFLAGS
Flags to pass to the C compiler when compiling the actual code.  If this
is not set, @code{configure} will use @samp{-g}.
@item LDFLAGS
Flags to pass to the C compiler when only linking, not compiling.  If
this is not set, @code{configure} will use the empty string.
@item LIBS
Libraries to pass to the C compiler.  If this is not set,
@code{configure} will use the empty string.
@item INSTALL
The program to run to install UUCP in the binary directory.  If this is
not set, then if @code{configure} finds the BSD @code{install} program,
it will set this to @samp{install -c}; otherwise, it will use @samp{cp}.
@item INSTALLDATA
The program to run to install UUCP data files, such as the man pages and
the info pages.  If this is not set, then if @code{configure} finds the
BSD @code{install} program, it will set this to @samp{install -c -m
644}; otherwise, it will use @samp{cp}.
@end table

Suppose you want to set the environment variable @samp{CC} to
@samp{rcc}.  If you are using @code{sh} or @code{bash}, invoke
@code{configure} as @samp{CC=rcc configure}.  If you are using
@code{csh}, do @samp{setenv CC rcc; sh configure}.

On some systems you will want to use @samp{LIBS=-lmalloc}.  On Xenix
derived versions of Unix do not use @samp{LIBS=-lx} because this will
bring in the wrong versions of certain routines; if you want to use
@samp{-lx} you must specify @samp{LIBS=-lc -lx}.

If @code{configure} fails for some reason, or if you have a very weird
system, you may have to configure the package by hand.  To do this, copy
the file @file{config.h.in} to @file{config.h} and edit it for your
system.  Then for each source directory (the top directory, and the
subdirectories @file{lib}, @file{unix}, and @file{uuconf}) copy
@file{Makefile.in} to @file{Makefile}, find the words within @kbd{@@}
characters, and set them correctly for your system.

@item
Igor V. Semenyuk provided this (lightly edited) note about ISC Unix 3.0.
The @code{configure} script will default to passing @samp{-posix} to
@code{gcc}.  However, using @samp{-posix} changes the environment to
POSIX, and on ISC 3.0, at least, the default for POSIX_NO_TRUNC is 1.
This means nothing for uucp, but can lead to a problem when uuxqt
executes rmail.  IDA sendmail has dbm configuration files named
@file{mailertable.@{dir,pag@}}.  Notice these names are 15 characters
long.  When uuxqt compiled with @samp{-posix} executes rmail, which in
turn executes sendmail, the later is run under POSIX environment too!
This leads to sendmail bombing out with @samp{'error opening 'M'
database: name too long' (mailertable.dir)}.  It's rather obscure
behaviour, and it took me a day to find out the cause.  I don't use
@samp{-posix}, instead I run @code{gcc} with @samp{-D_POSIX_SOURCE}, and
add @samp{-lcposix} to @samp{LIBS}.

@item
On some versions of BSDI there is a bug in the shell which causes the
default value for @samp{CFLAGS} to be set incorrectly.  If @samp{echo
$@{CFLAGS--g@}} echoes @samp{g} rather than @samp{-g}, then you must set
@samp{CFLAGS} in the environment before running configure.  There is a
patch available from BSDI for this bug.  (From David Vrona).

@item
On AIX 3.2.5, and possibly other versions, @samp{cc -E} does not work,
reporting @samp{Option NOROCONST is not valid}.  Test this before
running configure by doing something like @samp{touch /tmp/foo.c; cc -E
/tmp/foo.c}.  This may give a warning about the file being empty, but it
should not give the @samp{Option NOROCONST} warning.  The workaround is
to remove the @samp{,noroconst} entry from the @samp{options} clause in
the @samp{cc} stanza in @file{/etc/xlc.cfg}.  (From Chris Lewis).

@item
You should verify that @code{configure} worked correctly by checking
@file{config.h} and the instances of @file{Makefile}.

@item
Edit @file{policy.h} for your local system.  The comments should explain
the various choices.  The default values are intended to be reasonable,
so you may not have to make any changes.

@item
Type @samp{make} to compile everything.  The @file{tstuu.c} file is not
particularly portable; if you can't figure out how to compile it you can
safely ignore it, as it is only used for testing (to use STREAMS
pseudo-terminals, tstuu.c must be compiled with
@samp{-DHAVE_STREAMS_PTYS}; this is not automatically determined at the
moment).  If you have any other problems there is probably a bug in the
@code{configure} script.

@item
Please report any problems you have.  That is the only way they will get
fixed for other people.  Supply a patch if you can (@pxref{Patches}), or
just ask for help.

@end enumerate

@node Testing, Installation, Compilation, Overall Installation
@section Testing Taylor UUCP

This package is in use at hundreds, perhaps thousands, of sites, and has
been running at @file{airs.com} for several years.  However, it will
doubtless fail in some situations.  Do not rely on this code until you
have proven to yourself that it will work.

You can use the @code{uuchk} program to test your configuration files.
It will read them and print out a verbose description.  This program
should not be made setuid, because it will display passwords if it can
read them.

If your system supports pseudo-terminals, and you compiled the code to
support the new style of configuration files, you should be able to use
the @code{tstuu} program to test the @code{uucico} daemon (if your
system supports STREAMS based pseudo-terminals, you must compile tstuu.c
with @samp{-DHAVE_STREAMS_PTYS}, at least at the moment; the STREAMS
based code was contributed by Marc Boucher).

To run @code{tstuu}, just type @samp{tstuu} with no arguments while
logged in to the compilation directory (since it runs @file{./uucp},
@file{./uux} and @file{./uucico}).  It will run a lengthy series of
tests (it takes over ten minutes on a slow VAX).  You will need a fair
amount of space available in @file{/usr/tmp}.  You will probably want to
put it in the background.  Do not use @kbd{^Z}, because the program
traps on @code{SIGCHLD} and winds up dying.  It will create a directory
@file{/usr/tmp/tstuu} and fill it with configuration files, and create
spool directories @file{/usr/tmp/tstuu/spool1} and
@file{/usr/tmp/tstuu/spool2}.

If your system does not support the @code{FIONREAD} call, the
@samp{tstuu} program will run very slowly.  This may or may not get
fixed in a later version.

The program will finish with an execute file named
@file{X.@var{something}} and a data file named @file{D.@var{something}}
in the directory @file{/usr/tmp/tstuu/spool1} (or, more likely, in
subdirectories, depending on the choice of @code{SPOOLDIR} in
@file{policy.h}).  Two log files will be created in the directory
@file{/usr/tmp/tstuu}.  They will be named @file{Log1} and @file{Log2},
or, if you have selected @code{HAVE_HDB_LOGGING} in @file{policy.h},
@file{Log1/uucico/test2} and @file{Log2/uucico/test1}.  You can test
@code{uuxqt} by running the command @samp{./uuxqt -I
/usr/tmp/tstuu/Config1}.  This should leave a command file
@file{C.@var{something}} and a data file @file{D.@var{something}} in
@file{/usr/tmp/tstuu/spool1} or in subdirectories.  Again, there should
be no errors in the log file.

Assuming you compiled the code with debugging enabled, the @samp{-x}
switch can be used to set debugging modes; see the @code{debug} command
for details (@pxref{Debugging Levels}).  Use @samp{-x all} to turn on
all debugging and generate far more output than you will ever want to
see.  The @code{uucico} daemons will put debugging output in the files
@file{Debug1} and @file{Debug2} in the directory @file{/usr/tmp/tstuu}.
After that, you're pretty much on your own.

On some systems you can also use @code{tstuu} to test @code{uucico}
against the system @code{uucico}, by using the @samp{-u} switch.  For
this to work, change the definitions of @code{ZUUCICO_CMD} and
@code{UUCICO_EXECL} at the top of @file{tstuu.c} to something
appropriate for your system.  The definitions in @file{tstuu.c} are what
I used for Ultrix 4.0, on which @file{/usr/lib/uucp/uucico} is
particularly obstinate about being run as a child; I was only able to
run it by creating a login name with no password whose shell was
@file{/usr/lib/uucp/uucico}.  Calling login in this way will leave fake
entries in @file{wtmp} and @file{utmp}; if you compile @file{tstout.c}
(in the @file{contrib} directory) as a setuid @code{root} program,
@code{tstuu} will run it to clear those entries out.  On most systems,
such hackery should not be necessary, although on SCO I had to su to
@code{root} (@code{uucp} might also have worked) before I could run
@file{/usr/lib/uucp/uucico}.

You can test @code{uucp} and @code{uux} (give them the @samp{-r} switch
to keep them from starting @code{uucico}) to make sure they create the
right sorts of files.  Unfortunately, if you don't know what the right
sorts of files are, I'm not going to tell you here.

If @code{tstuu} passes, or you can't run it for some reason or other,
move on to testing with some other system.  Set up the configuration
files (@pxref{Configuration Files}), or use an existing configuration.
Tell @code{uucico} to dial out to the system by using the @samp{-s}
system switch (e.g.  @samp{uucico -s uunet}).  The log file should tell
you what happens.

If you compiled the code with debugging enabled, you can use debugging
mode to get a great deal of information about what sort of data is
flowing back and forth; the various possibilities are described under
the @code{debug} command (@pxref{Debugging Levels}).  When initially
setting up a connection @samp{-x chat} is probably the most useful (e.g.
@samp{uucico -s uunet -x chat}); you may also want to use @samp{-x
handshake,incoming,outgoing}.  You can use @samp{-x} multiple times on
one command line, or you can give it comma separated arguments as in the
last example.  Use @samp{-x all} to turn on all possible debugging
information.  The debugging information is written to a file, normally
@file{/usr/spool/uucp/Debug}, although the default can be changed in
@file{policy.h} and the @file{config} file can override the name with
the @code{debugfile} command.  The debugging file may contain passwords
and some file contents as they are transmitted over the line, so the
debugging file is only readable by the @code{uucp} user.

You can use the @samp{-f} switch to force @code{uucico} to call out even
if the last call failed recently; using @samp{-S} when naming a system
has the same effect.  Otherwise the status file (in the @file{.Status}
subdirectory of the main spool directory, normally
@file{/usr/spool/uucp}) will prevent too many attempts from occurring in
rapid succession.

Again, please let me know about any problems you have and how you got
around them.  If you do report a problem, please include the version
number of the package you are using, and a sample of the debugging file
showing the problem (debugging information is usually what is needed,
not just the log file).  General questions such as ``why doesn't uucico
dial out'' are impossible to answer without much more information.

@node Installation, TCP, Testing, Overall Installation
@section Installing Taylor UUCP

You can install the executable files by becoming @code{root} and typing
@samp{make install}.  Or you can look at what @samp{make install} does
and do it by hand.  It tries to preserve your old programs, if any, but
it only does this the first time Taylor UUCP is installed (so that if
you install several versions of Taylor UUCP, you can still go back to
your original UUCP programs).  You can retrieve the original programs by
typing @samp{make uninstall}.

Note that by default the programs are compiled with debugging
information, and they are not stripped when they are installed.  You may
want to strip the installed programs to save disk space.  See your
system documentation for strip for more information.

However, simply installing the executable files is not enough.  You must
also arrange for them to be used correctly.

@menu
* Running uucico::              Running uucico
* Using UUCP for mail and news::  Using UUCP for mail and news.
* Trimming UUCP Log Files::     Trimming UUCP Log Files
@end menu

@node Running uucico, Using UUCP for mail and news, Installation, Installation
@subsection Running uucico

By default @code{uucp} and @code{uux} will automatically start up
@code{uucico} to call another system whenever work is queued up.
However, the call may fail, or you may have put in time restrictions
which prevent the call at that time (perhaps because telephone rates are
high) (@pxref{When to Call}).  Also, a remote system may have work
queued up for your system, but may not be calling you for some reason
(perhaps you have agreed that your system should always place the call).
To make sure that works get transferred between the systems withing a
reasonable time period, you should arrange to periodically invoke
@code{uucico}.

These periodic invocations are normally caused by entries in the
@file{crontab} file.  The exact format of @file{crontab} files, and how
new entries are added, varies from system to system; check your local
documentation (try @samp{man cron}).

To attempt to call all systems with outstanding work, use the command
@samp{uucico -r1}.  To attempt to call a particular system, use the
command @samp{uucico -s @var{system}}.  To attempt to call a particular
system, but only if there is work for it, use the command @samp{uucico
-C -s @var{system}}.

A common case is to want to try to call a system at a certain time, with
periodic retries if the call fails.  A simple way to do this is to
create an empty UUCP command file, known as a @dfn{poll file}.  If a
poll file exists for a system, then @samp{uucico -r1} will place a call
to it.  If the call succeeds, the poll file will be deleted.

The file can be easily created using the @samp{touch} command.  The name
of a poll file currently depends on the type of spool directory you are
using, as set in @file{policy.h}.  If you are using
@code{SPOOLDIR_TAYLOR} (the default), put something like this in your
@file{crontab} file:
@example
touch /usr/spool/uucp/@var{sys}/C./C.A0000
@end example
In this example @var{sys} is the system you wish to call, and
@samp{/usr/spool/uucp} is your UUCP spool directory.
If you are using @code{SPOOLDIR_HDB}, use
@example
touch /usr/spool/uucp/@var{sys}/C.@var{sys}A0000
@end example

For example, I use the following crontab entries locally:

@example
45 * * * * /bin/echo /usr/lib/uucp/uucico -r1 | /bin/su uucpa
40 4,10,15 * * * touch /usr/spool/uucp/uunet/C./C.A0000
@end example

Every hour, at 45 minutes past, this will check if there is any work to
be done, and, if there is, will call the appropriate system.  Also, at
4:40am, 10:40am and 3:40pm this will create a poll file file for
@samp{uunet}, forcing the next check to call @samp{uunet}.

@node Using UUCP for mail and news, Trimming UUCP Log Files, Running uucico, Installation
@subsection Using UUCP for mail and news.

Taylor UUCP does not include a mail package.  All Unix systems come with
some sort of mail delivery agent, typically @code{sendmail} or
@code{MMDF}.  Source code is available for some alternative mail
delivery agents, such as @code{IDA sendmail} and @code{smail}.

Taylor UUCP also does not include a news package.  The two major Unix
news packages are @code{C-news} and @code{INN}.  Both are available in
source code form.

Configuring and using mail delivery agents is a notoriously complex
topic, and I will not be discussing it here.  Configuring news systems
is usually simpler, but I will not be discussing that either.  I will
merely describe the interactions between the mail and news systems and
UUCP.

A mail or news system interacts with UUCP in two ways: sending and
receiving.

@menu
* Sending mail or news::        Sending mail or news via UUCP
* Receiving mail or news::      Receiving mail or news via UUCP
@end menu

@node Sending mail or news, Receiving mail or news, Using UUCP for mail and news, Using UUCP for mail and news
@unnumberedsubsubsec Sending mail or news via UUCP

When mail is to be sent from your machine to another machine via UUCP,
the mail delivery agent will invoke @code{uux}.  It will generally run a
command such as @samp{uux - @var{system}!rmail}, where @var{system} is
the remote system to which the mail is being sent.  It may pass other
options to @code{uux}, such as @samp{-r} or @samp{-g}.

News also invokes @code{uux} in order to transfer articles to another
system.  The only difference is that news will use @code{uux} to invoke
@code{rnews} on the remote system, rather than @code{rmail}.

You should arrange for your mail and news systems to invoke the Taylor
UUCP version of @code{uux} when sending mail via UUCP.  If you simply
replace any existing version of @code{uux} with the Taylor UUCP version,
this will probably happen automatically.  However, if both versions
exist on your system, you will probably have to modify the mail and news
configuration files in some way.

Actually, if both the system UUCP and Taylor UUCP are using the same
spool directory format, the system @code{uux} will probably work fine
with the Taylor @code{uucico} (the reverse is not the case: the Taylor
@code{uux} requires the Taylor @code{uucico}).  However, data transfer
will be somewhat more efficient if the Taylor @code{uux} is used.

@node Receiving mail or news,  , Sending mail or news, Using UUCP for mail and news
@unnumberedsubsubsec Receiving mail or news via UUCP

As noted in @ref{Sending mail or news}, mail is sent by requesting a
remote execution of @code{rmail}.  To receive mail, then, all that is
necessary is for UUCP to invoke @code{rmail} itself.

Any mail delivery agent will provide an appropriate version of
@code{rmail}; you must simply make sure that it is in the command path
used by UUCP (it almost certainly already is).  The default command path
is set in @file{policy.h}, and it may be overridden for a particular
system by the @code{command-path} command (@pxref{Miscellaneous (sys)}).

Similarly, for news UUCP must be able to invoke @code{rnews}.  Any news
system will provide a version of @code{rnews}, and you must ensure that
is in a directory on the path that UUCP will search.

@node Trimming UUCP Log Files,  , Using UUCP for mail and news, Installation
@subsection Trimming UUCP Log Files

You should also periodically trim the log files, as they will otherwise
continue to grow without limit.  The names of the log files are set in
@file{policy.h}, and may be overridden in the configuration file
(@pxref{config File}).  By default they are are
@file{/usr/spool/uucp/Log} and @file{/usr/spool/uucp/Stats}.

You may find the @code{savelog} program in the @file{contrib} directory
to be of use.  There is a manual page for it in @file{contrib} as well.

@node TCP,  , Installation, Overall Installation
@section TCP together with Taylor UUCP

If your system has a Berkeley style socket library, or a System V style
TLI interface library, you can compile the code to permit making
connections over TCP.  Specifying that a system should be reached via
TCP is easy, but nonobvious.

If you are using the new style configuration files, see
@ref{Configuration Files}.  Basically, you can just add the line
@samp{port type tcp} to the entry in the system configuration file.  By
default UUCP will get the port number by looking up @samp{uucp} in
@file{/etc/services}; if @samp{uucp} is not found, port 540 will be
used.  You can set the port number to use with the command @samp{port
service @var{xxx}}, where @var{xxx} can be either a number or a name to
look up in @file{/etc/services}.  You can specify the address of the
remote host with @samp{address @var{a.b.c}}; if you don't give an
address, the remote system name will be used.  You should give an
explicit chat script for the system when you use TCP; the default chat
script begins with a carriage return, which will not work with some UUCP
TCP servers.

If you are using V2 configuration files, add a line like this to
@file{L.sys}:

@example
@var{sys} Any TCP uucp @var{host}.@var{domain} chat-script
@end example

This will make an entry for system @var{sys}, to be called at any time,
over TCP, using port number @samp{uucp} (as found in
@file{/etc/services}; this may be specified as a number), using remote
host @file{@var{host}.@var{domain}}, with some chat script.

@need 1000
If you are using HDB configuration files, add a line like this to
Systems:

@example
@var{sys} Any TCP - @var{host}.@var{domain} chat-script
@end example

and a line like this to Devices:

@example
TCP uucp - -
@end example

You only need one line in Devices regardless of how many systems you
contact over TCP.  This will make an entry for system @var{sys}, to be
called at any time, over TCP, using port number @samp{uucp} (as found in
@file{/etc/services}; this may be specified as a number), using remote
host @file{@var{host}.@var{domain}}, with some chat script.

The @code{uucico} daemon can also be run as a TCP server.  To use the
default port number, which is a reserved port, @code{uucico} must be
invoked by root (or it must be set user ID to root, but I don't
recommend doing that).

Basically, you must define a port, either using the port file
(@pxref{port File}) if you are using the new configuration method or
with an entry in Devices if you are using HDB; there is no way to define
a port using V2.  If you are using HDB the port must be named
@samp{TCP}; a line as shown above will suffice.  You can then start
@code{uucico} as @samp{uucico -p TCP} (after the @samp{-p}, name the
port; in HDB it must be @samp{TCP}).  This will wait for incoming
connections, and fork off a child for each one.  Each connection will be
prompted with @samp{login:} and @samp{Password:}; the results will be
checked against the UUCP (not the system) password file
(@pxref{Configuration File Names}).

Of course, you can get a similar effect by using the BSD @code{uucpd}
program.

You can also have @code{inetd} start up @code{uucico} with the @samp{-l}
switch, which will cause it to prompt with @samp{login:} and
@samp{Password:} and check the results against the UUCP (not the system)
password file (you may want to also use the @samp{-D} switch to avoid a
fork, which in this case is unnecessary).  This may be used in place of
@code{uucpd}.

@node Configuration Files, Protocols, Overall Installation, Top
@chapter Taylor UUCP Configuration Files

This chapter describes the configuration files accepted by the Taylor
UUCP package if compiled with @code{HAVE_TAYLOR_CONFIG} defined in
@file{policy.h}.

The configuration files are normally found in the directory
@var{newconfigdir}, which is defined by the @file{Makefile} variable
@file{newconfigdir}; by default @var{newconfigdir} is
@file{/usr/local/conf/uucp}.  However, the main configuration file,
@file{config}, is the only one which must be in that directory, since it
may specify a different location for any or all of the other files.  You
may run any of the UUCP programs with a different main configuration
file by using the @samp{-I} option; this can be useful when testing a
new configuration.  When you use the @samp{-I} option the programs will
revoke any setuid privileges.

@menu
* Configuration File Format::   Configuration file format
* Configuration File Overview::  Configuration File Overview
* Configuration Examples::      Examples of configuration files
* Time Strings::                How to write time strings
* Chat Scripts::                How to write chat scripts
* config File::                 The main configuration file
* sys File::                    The system configuration file
* port File::                   The port configuration files
* dial File::                   The dialer configuration files
* Security::                    Security issues
@end menu

@node Configuration File Format, Configuration File Overview, Configuration Files, Configuration Files
@section Configuration File Format

All the configuration files follow a simple line-oriented
@samp{@var{keyword} @var{value}} format.  Empty lines are ignored, as
are leading spaces; unlike HDB, lines with leading spaces are read.  The
first word on each line is a keyword.  The rest of the line is
interpreted according to the keyword.  Most keywords are followed by
numbers, boolean values or simple strings with no embedded spaces.

The @kbd{#} character is used for comments.  Everything from a @kbd{#}
to the end of the line is ignored unless the @kbd{#} is preceded by a
@kbd{\} (backslash); if the @kbd{#} is preceeded by a @kbd{\}, the
@kbd{\} is removed but the @kbd{#} remains in the line.  This can be
useful for a phone number containing a @kbd{#}.  To enter the sequence
@samp{\#}, use @samp{\\#}.  

The backslash character may be used to continue lines.  If the last
character in a line is a backslash, the backslash is removed and the
line is continued by the next line.  The second line is attached to the
first with no intervening characters; if you want any whitespace between
the end of the first line and the start of the second line, you must
insert it yourself.

However, the backslash is not a general quoting character.  For example,
you cannot use it to get an embedded space in a string argument.

Everything after the keyword must be on the same line.  A @var{boolean}
may be specified as @kbd{y}, @kbd{Y}, @kbd{t}, or @kbd{T} for true and
@kbd{n}, @kbd{N}, @kbd{f}, or @kbd{F} for false; any trailing characters
are ignored, so @code{true}, @code{false}, etc., are also acceptable.

@node Configuration File Overview, Configuration Examples, Configuration File Format, Configuration Files
@section Configuration File Overview

UUCP uses several different types of configuration files, each
describing a different kind of information.  The commands permitted in
each file are described in detail below.  This section is a brief
description of some of the different types of files.

The @file{config} file is the main configuration file.  It describes
general information not associated with a particular remote system, such
as the location of various log files.  There are reasonable defaults for
everything that may be specified in the @file{config} file, so you may
not actually need one on your system.

There may be only one @file{config} file, but there may be one or more
of each other type of file.  The default is one file for each type, but
more may be listed in the @file{config} file.

The @file{sys} files are used to describe remote systems.  Each remote
system to which you connect must be listed in a @file{sys} file.  A
@file{sys} file will include information for a system, such as the speed
(baud rate) to use, or when to place calls.

For each system you wish to call, you must describe one or more ports;
these ports may be defined directly in the @file{sys} file, or they may
be defined in a @file{port} file.

The @file{port} files are used to describe ports.  A port is a
particular hardware connection on your computer.  You would normally
define as many ports as there are modems attached to your computer.  A
TCP connection is also described using a port.

The @file{dial} files are used to describe dialers.  Dialer is
essentially another word for modem.  The @file{dial} file describes the
commands UUCP should use to dial out on a particular type of modem.  You
would normally define as many dialers as there are types of modems
attached to your computer.  For example, if you have three Telebit
modems used for UUCP, you would probably define three ports and one
dialer.

There are other types of configuration files, but these are the
important ones.  The other types are described below.

@node Configuration Examples, Time Strings, Configuration File Overview, Configuration Files
@section Examples of Configuration Files

This section provides few typical examples of configuration files.
There are also sample configuration files in the @file{sample}
subdirectory of the distribution.

@menu
* config File Examples::        Examples of the main configuration file
* Leaf Example::                Call a single remote site
* Gateway Example::             The gateway for several local systems
@end menu

@node config File Examples, Leaf Example, Configuration Examples, Configuration Examples
@subsection config File Examples
@cindex config file examples

To start with, here are some examples of uses of the main configuration
file, @file{config}.  For a complete description of the commands that
are permitted in @file{config}, see @ref{config File}.

In many cases you will not need to create a @file{config} file at all.
The most common reason to create one is to give your machine a special
UUCP name.  Other reasons might be to change the UUCP spool directory or
to permit any remote system to call in.

If you have an internal network of machines, then it is likely that the
internal name of your UUCP machine is not the name you want to use when
calling other systems.  For example, here at @file{airs.com} our
mail/news gateway machine is named @file{elmer.airs.com} (it is one of
several machines all named @file{@var{localname}.airs.com}).  If we did
not provide a @file{config} file, then our UUCP name would be
@file{elmer}; however, we actually want it to be @file{airs}.
Therefore, we use the following line in @file{config}:

@example
nodename airs
@end example

@cindex changing spool directory
@cindex spool directory (changing)
The UUCP spool directory name is set in @file{policy.h} when the code is
compiled.  You might at some point decide that it is appropriate to move
the spool directory, perhaps to put it on a different disk partition.
You would use the following commands in @file{config} to change to
directories on the partition @file{/uucp}:

@example
spool /uucp/spool
pubdir /uucp/uucppublic
logfile /uucp/spool/Log
debugfile /uucp/spool/Debug
@end example

You would then move the contents of the current spool directory to
@file{/uucp/spool}.  If you do this, make sure that no UUCP processes
are running while you change @file{config} and move the spool directory.

@cindex anonymous UUCP
Suppose you wanted to permit any system to call in to your system and
request files.  This is generally known as @dfn{anonymous UUCP}, since
the systems which call in are effectively anonymous.  By default,
unknown systems are not permitted to call in.  To permit this you must
use the @code{unknown} command in @file{config}.  The @code{unknown}
command is followed by any command that may appear in the system file;
for full details, see @ref{sys File}.

I will show two possible anonymous UUCP configurations.  The first will
let any system call in and download files, but will not permit them to
upload files to your system.

@example
# No files may be transferred to this system
unknown receive-request no
# The public directory is /usr/spool/anonymous
unknown pubdir /usr/spool/anonymous
# Only files in the public directory may be sent (the default anyhow)
unknown remote-send ~
@end example

@noindent
Setting the public directory is convenient for the systems which call
in.  It permits to request a file by prefixing it with @file{~/}.  For
example, assuming your system is known as @samp{server}, then to
retrieve the file @file{/usr/spool/anonymous/INDEX} a user on a remote
site could just enter @samp{uucp server!~/INDEX ~}; this would transfer
@file{INDEX} from @samp{server}'s public directory to the user's local
public directory.  Note that when using @samp{csh} or @samp{bash} the
@kbd{!} and the second @kbd{~} must be quoted.

The next example will permit remote systems to upload files to a special
directory named @file{/usr/spool/anonymous/upload}.  Permitting a remote
system to upload files permits it to send work requests as well; this
example is careful to prohibit commands from unknown systems.

@example
# No commands may be executed (the list of permitted commands is empty)
unknown commands
# The public directory is /usr/spool/anonymous
unknown pubdir /usr/spool/anonymous
# Only files in the public directory may be sent; users may not download
# files from the upload directory
unknown remote-send ~ !~/upload
# May only upload files into /usr/spool/anonymous/upload
unknown remote-receive ~/upload
@end example

@node Leaf Example, Gateway Example, config File Examples, Configuration Examples
@subsection Leaf Example

@cindex leaf site
@cindex sys file example (leaf)
A relatively common simple case is a @dfn{leaf site}, a system which
only calls or is called by a single remote site.  Here is a typical
@file{sys} file that might be used in such a case.  For full details on
what commands can appear in the @file{sys} file, see @ref{sys File}.

This is the @file{sys} file that is used at @file{airs.com}.  We use a
single modem to dial out to @file{uunet}.  This example shows how you
can specify the port and dialer information directly in the @file{sys}
file for simple cases.  It also shows the use of the following:

@table @code

@item call-login
Using @code{call-login} and @code{call-password} allows the default
login chat script to be used.  In this case, the login name is specified
in the call-out login file (@pxref{Configuration File Names}).

@item call-timegrade
@file{uunet} is requested to not send us news during the daytime.

@item chat-fail
If the modem returns @samp{BUSY} or @samp{NO CARRIER} the call is
immediately aborted.

@item protocol-parameter
Since @file{uunet} tends to be slow, the default timeout has been
increased.

@end table

This @file{sys} file relies on certain defaults.  It will allow
@file{uunet} to queue up @samp{rmail} and @samp{rnews} commands.  It
will allow users to request files from @file{uunet} into the UUCP public
directory.  It will also allow @file{uunet} to request files from the
UUCP public directory; in fact @file{uunet} never requests files, but
for additional security we could add the line @samp{request false}.

@example
# The following information is for uunet
system uunet

# The login name and password are kept in the callout password file
call-login *
call-password *

# We can send anything at any time.
time any

# During the day we only accept grade `Z' or above; at other times
# (not mentioned here) we accept all grades.  uunet queues up news
# at grade `d', which is lower than `Z'.
call-timegrade Z Wk0755-2305,Su1655-2305

# The phone number.
phone 7389449

# uunet tends to be slow, so we increase the timeout
chat-timeout 120

# We are using a preconfigured Telebit 2500.
port type modem
port device /dev/ttyd0
port speed 19200
port carrier true
port dialer chat "" ATZ\r\d\c OK ATDT\D CONNECT
port dialer chat-fail BUSY
port dialer chat-fail NO\sCARRIER
port dialer complete \d\d+++\d\dATH\r\c
port dialer abort \d\d+++\d\dATH\r\c

# Increase the timeout and the number of retries.
protocol-parameter g timeout 20
protocol-parameter g retries 10
@end example

@node Gateway Example,  , Leaf Example, Configuration Examples
@subsection Gateway Example

@cindex gateway
@cindex sys file example (gateway)
Many organizations have several local machines which are connected by
UUCP, and a single machine which connects to the outside world.  This
single machine is often referred to as a @dfn{gateway} machine.

For this example I will assume a fairly simple case.  It should still
provide a good general example.  There are three machines, @file{elmer},
@file{comton} and @file{bugs}.  @file{elmer} is the gateway machine for
which I will show the configuration file.  @file{elmer} calls out to
@file{uupsi}.  As an additional complication, @file{uupsi} knows
@file{elmer} as @file{airs}; this will show how a machine can have one
name on an internal network but a different name to the external world.
@file{elmer} has two modems.  It also has an TCP/IP connection to
@file{uupsi}, but since that is supposed to be reserved for interactive
work (it is, perhaps, only a 9600 baud SLIP line) it will only use it if
the modems are not available.

A network this small would normally use a single @file{sys} file.
However, for pedagogical purposes I will show two separate @file{sys}
files, one for the local systems and one for @file{uupsi}.  This is done
with the @code{sysfile} command in the @file{config} file.  Here is the
@file{config} file.

@example
# This is config
# The local sys file
sysfile /usr/local/lib/uucp/sys.local
# The remote sys file
sysfile /usr/local/lib/uucp/sys.remote
@end example

Using the defaults feature of the @file{sys} file can greatly simplify
the listing of local systems.  Here is @file{sys.local}.  Note that this
assumes that the local systems are trusted; they are permited to request
any world readable file and to write files into any world writable
directory.

@example
# This is sys.local
# Get the login name and password to use from the call-out file
call-login *
call-password *

# The systems must use a particular login
called-login Ulocal

# Permit sending any world readable file
local-send /
remote-send /

# Permit requesting into any world writable directory
local-receive /
remote-receive /

# Call at any time
time any

# Use port1, then port2
port port1

alternate

port port2

# Now define the systems themselves.  Because of all the defaults we
# used, there is very little to specify for the systems themselves.

system comton
phone 5551212

system bugs
phone 5552424
@end example

The @file{sys.remote} file describes the @file{uupsi} connection.  The
@code{myname} command is used to change the UUCP name to @file{airs}
when talking to @file{uupsi}.

@example
# This is sys.remote
# Define uupsi
system uupsi

# The login name and password are in the call-out file
call-login *
call-password *

# We can call out at any time
time any

# uupsi uses a special login name
called-login Uuupsi

# uuspi thinks of us as `airs'
myname airs

# The phone number
phone 5554848

# We use port2 first, then port1, then TCP

port port2

alternate

port port1

alternate

# We don't bother to make a special entry in the port file for TCP, we
# just describe the entire port right here.  We use a special chat
# script over TCP because the usual one confuses some TCP servers.
port type TCP
address uu.psi.com
chat ogin: \L word: \P
@end example

The ports are defined in the file @file{port} (@pxref{port File}).  For
this example they are both connected to the same type of 2400 baud
Hayes-compatible modem.

@example
# This is port

port port1
type modem
device /dev/ttyd0
dialer hayes
speed 2400

port port2
type modem
device /dev/ttyd1
dialer hayes
speed 2400
@end example

Dialers are described in the @file{dial} file (@pxref{dial File}).

@example
# This is dial

dialer hayes

# The chat script used to dial the phone.  \D is the phone number.
chat "" ATZ\r\d\c OK ATDT\D CONNECT

# If we get BUSY or NO CARRIER we abort the dial immediately
chat-fail BUSY
chat-fail NO\sCARRIER

# When the call is over we make sure we hangup the modem.
complete \d\d+++\d\dATH\r\c
abort \d\d+++\d\dATH\r\c
@end example

@node Time Strings, Chat Scripts, Configuration Examples, Configuration Files
@section Time Strings
@cindex time strings

Several commands use time strings to specify a range of times.  This
section describes how to write time strings.

A time string may be a list of simple time strings separated with a
vertical bar @kbd{|} or a comma @kbd{,}.

Each simple time string must begin with @samp{Su}, @samp{Mo}, @samp{Tu},
@samp{We}, @samp{Th}, @samp{Fr}, or @samp{Sa}, or @samp{Wk} for any
weekday, or @samp{Any} for any day.

Following the day may be a range of hours separated with a hyphen using
24 hour time.  The range of hours may cross 0; for example
@samp{2300-0700} means any time except 7 AM to 11 PM.  If no time is
given, calls may be made at any time on the specified day(s).  

The time string may also consist of the single word @samp{Never}, which
does not match any time, or a single word with a name defined in a
previous @code{timetable} command (@pxref{Miscellaneous (config)}).

Here are a few sample time strings with an explanation of what they
mean.

@table @samp

@item Wk2305-0855,Sa,Su2305-1655

This means weekdays before 8:55 AM or after 11:05 PM, any time Saturday,
or Sunday before 4:55 PM or after 11:05 PM.  These are approximately the
times during which night rates apply to phone calls in the U.S.A.  Note
that this time string uses, for example, @samp{2305} rather than
@samp{2300}; this will ensure a cheap rate phone call even if the
computer clock is running up to five minutes ahead of the real time.

@item Wk0905-2255,Su1705-2255

This means weekdays from 9:05 AM to 10:55 PM, or Sunday from 5:05 PM to
10:55 PM.  This is approximately the opposite of the previous example.

@item Any

This means any day.  Since no time is specified, it means any time on
any day.

@end table

@node Chat Scripts, config File, Time Strings, Configuration Files
@section Chat Scripts
@cindex chat scripts

Chat scripts are used in several different places, such as dialing out
on modems or logging in to remote systems.  Chat scripts are made up of
pairs of strings.  The program waits until it sees the first string,
known as the @dfn{expect} string, and then sends out the second string,
the @dfn{send} string.

Each chat script is defined using a set of commands.  These commands
always end in a string beginning with @code{chat}, but may start with
different strings.  For example, in the @file{sys} file there is one set
of commands beginning with @code{chat} and another set beginning with
@code{called-chat}.  The prefixes are only used to disambiguate
different types of chat scripts, and this section ignores the prefixes
when describing the commands.

@table @code

@item chat @var{strings}
@findex chat

Specify a chat script.  The arguments to the @code{chat} command are
pairs of strings separated by whitespace.  The first string of each pair
is an expect string, the second is a send string.  The program will wait
for the expect string to appear; when it does, the program will send the
send string.  If the expect string does not appear within a certain
number of seconds (as set by the @code{chat-timeout} command) the chat
script fails and, typically, the call is aborted.  If the final expect
string is seen (and the optional final send string has been sent), the
chat script is successful.

An expect string may contain additional subsend and subexpect strings,
separated by hyphens.  If the expect string is not seen, the subsend
string is sent and the chat script continues by waiting for the
subexpect string.  This means that a hyphen may not appear in an expect
string; on an ASCII system, use @samp{\055} instead.

An expect string may simply be @samp{""}, meaning to skip the expect
phase.  Otherwise, the following escape characters may appear in expect
strings:

@table @samp
@item \b
a backspace character
@item \n
a newline or line feed character
@item \N
a null character (for HDB compatibility)
@item \r
a carriage return character
@item \s
a space character
@item \t
a tab character
@item \\
a backslash character
@item \@var{ddd}
character @var{ddd}, where @var{ddd} are up to three octal digits
@item \x@var{ddd}
character @var{ddd}, where @var{ddd} are hexadecimal digits.
@end table

As in C, there may be up to three octal digits following a backslash,
but the hexadecimal escape sequence continues as far as possible.  To
follow a hexadecimal escape sequence with a hex digit, interpose a send
string of @samp{""}.

A chat script expect string may also specify a timeout.  This is done by
using the escape sequence @samp{\W@var{seconds}}.  This escape sequence
may only appear at the very end of the expect string.  It temporarily
overrides the timeout set by @code{chat-timeout} (described below) only
for the expect string to which it is attached.

A send string may simply be @samp{""} to skip the send phase.
Otherwise, all of the escape characters legal for expect strings may be
used, and the following escape characters are also permitted:

@table @samp
@item EOT
send an end of transmission character (@kbd{^D})
@item BREAK
send a break character (may not work on all systems)
@item \c
suppress trailing carriage return at end of send string
@item \d
delay sending for 1 or 2 seconds
@item \e
disable echo checking
@item \E
enable echo checking
@item \K
same as @samp{BREAK} (for HDB compatibility)
@item \p
pause sending for a fraction of a second
@end table

Some specific types of chat scripts also define additional escape
sequences that may appear in the send string.  For example, the login
chat script defines @samp{\L} and @samp{\P} to send the login name and
password, respectively.

A carriage return will be sent at the end of each send string, unless
the @kbd{\c} escape sequence appears in the string.  Note that some UUCP
packages use @kbd{\b} for break, but here it means backspace.

Echo checking means that after writing each character the program will
wait until the character is echoed.  Echo checking must be turned on
separately for each send string for which it is desired; it will be
turned on for characters following @kbd{\E} and turned off for characters
following @kbd{\e}.

@item chat-timeout @var{number}
@findex chat-timeout

The number of seconds to wait for an expect string in the chat script
before timing out and sending the next subsend or failing the chat
script entirely.  The default value is 10 for a login chat or 60 for
any other type of chat.

@item chat-fail @var{string}
@findex chat-fail

If the @var{string} is seen at any time during a chat script, the chat
script is aborted.  The string may not contain any whitespace
characters; escape sequences must be used for them.  Multiple
@code{chat-fail} commands may appear in a single chat script.  The
default is to have none.

This permits a chat script to be quickly aborted if an error string is
seen.  For example, a script used to dial out on a modem might use the
command @samp{chat-fail BUSY} to stop the chat script immediately if the
string @samp{BUSY} was seen.

The @code{chat-fail} strings are considered in the order they are
listed, so if one string is a suffix of another the longer one should be
listed first.  Of course, if one string is contained within another, the
smaller string will always be found before the larger string could
match.

@item chat-seven-bit @var{boolean}
@findex chat-seven-bit

If the argument is true, all incoming characters are stripped to seven
bits when being compared to the expect string.  Otherwise all eight bits
are used in the comparison.  The default is true, because some Unix
systems generate parity bits during the login prompt which must be
ignored while running a chat script.  This has no effect on any
@code{chat-program}, which must ignore parity by itself if necessary.

@item chat-program @var{strings}
@findex chat-program

Specify a program to run before executing the chat script.  This program
could run its own version of a chat script, or it could do whatever it
wants.  If both @code{chat-program} and @code{chat} are specified, the
program is executed first followed by the chat script.

The first argument to the @code{chat-program} command is the program
name to run.  The remaining arguments are passed to the program.  The
following escape sequences are recognized in the arguments:

@table @kbd
@item \Y
port device name
@item \S
port speed
@item \\
backslash
@end table

Some specific uses of @code{chat-program} define additional escape
sequences.

Arguments other than escape sequences are passed exactly as they appear
in the configuration file, except that sequences of whitespace are
compressed to a single space character (this exception may be removed in
the future).

If the @code{chat-program} command is not used, no program is run.

On Unix, the standard input and standard output of the program will be
attached to the port in use.  Anything the program writes to standard
error will be written to the UUCP log file.  No other file descriptors
will be open.  If the program does not exit with a status of 0, it will
be assumed to have failed.  This means that the dialing programs used by
some versions of HDB may not be used directly, but you may be able to
run them via the @code{dialHDB} program in the @file{contrib} directory.

The program will be run as the @code{uucp} user, and the environment
will be that of the process that started @code{uucico}, so care must be
taken to maintain security.

No search path is used to find the program; a full path name must be
given.  If the program is an executable shell script, it will be passed
to @file{/bin/sh} even on systems which are unable to execute shell
scripts.

@end table

Here is a simple example of a chat script that might be used to reset a
Hayes compatible modem.

@example
chat "" ATZ OK-ATZ-OK
@end example

The first expect string is @samp{""}, so it is ignored.  The chat script
then sends @samp{ATZ}.  If the modem responds with @samp{OK}, the chat
script finishes.  If 60 seconds (the default timeout) pass before seeing
@samp{OK}, the chat script sends another @samp{ATZ}.  If it then sees
@samp{OK}, the chat script succeeds.  Otherwise, the chat script fails.

For a more complex chat script example, see @ref{Logging In}.

@node config File, sys File, Chat Scripts, Configuration Files
@section The Main Configuration File
@cindex config file
@cindex main configuration file
@cindex configuration file (config)

The main configuration file is named @file{config}.

Since all the values that may be specified in the main configuration
file also have defaults, there need not be a main configuration file at
all.

Each command in @file{config} may have a program prefix, which is a
separate word appearing at the beginning of the line.  The currently
supported prefixes are @samp{uucp} and @samp{cu}.  Any command prefixed
by @samp{uucp} will not be read by the @code{cu} program.  Any command
prefixed by @samp{cu} will only be read by the @code{cu} program.  For
example, to use a list of systems known only to @code{cu}, list them in
a separate file @file{@var{file}} and put @samp{cu sysfile
@file{@var{file}}} in @file{config}.

@menu
* Miscellaneous (config)::      Miscellaneous config file commands
* Configuration File Names::    Using different configuration files
* Log File Names::              Using different log files
* Debugging Levels::            Debugging levels
@end menu

@node Miscellaneous (config), Configuration File Names, config File, config File
@subsection Miscellaneous config File Commands

@table @code

@item nodename @var{string}
@findex nodename
@itemx hostname @var{string}
@findex hostname
@itemx uuname @var{string}
@findex uuname
@cindex UUCP system name
@cindex system name

These keywords are equivalent.  They specify the UUCP name of the local
host.  If there is no configuration file, an appropriate system function
will be used to get the host name, if possible.

@item spool @var{string}
@findex spool
@cindex spool directory
@cindex /usr/spool/uucp

Specify the spool directory.  The default is from @file{policy.h}.  This
is where UUCP files are queued.  Status files and various sorts of
temporary files are also stored in this directory and subdirectories of
it.

@item pubdir @var{string}
@findex pubdir in config file
@cindex public directory
@cindex uucppublic
@cindex /usr/spool/uucppublic

Specify the public directory.  The default is from @file{policy.h}.
When a file is named using a leading @kbd{~/}, it is taken from or to
the public directory.  Each system may use a separate public directory
by using the @code{pubdir} command in the system configuration file; see
@ref{Miscellaneous (sys)}.

@item lockdir @var{string}
@findex lockdir
@cindex lock directory

Specify the directory to place lock files in.  The default is from
@file{policy.h}; see the information in that file.  Normally the lock
directory should be set correctly in @file{policy.h}, and not changed
here.  However, changing the lock directory is sometimes useful for
testing purposes.

@item unknown @var{string} @dots{}
@findex unknown
@cindex unknown systems

The @var{string} and subsequent arguments are treated as though they
appeared in the system file (@pxref{sys File}).  They are used to apply
to any unknown systems that may call in, probably to set file transfer
permissions and the like.  If the @code{unknown} command is not used,
unknown systems are not permitted to call in.

@item max-uuxqts @var{number}
@findex max-uuxqts

Specify the maximum number of @code{uuxqt} processes which may run at
the same time.  Having several @code{uuxqt} processes running at once
can significantly slow down a system, but since @code{uuxqt} is
automatically started by @code{uucico}, it can happen quite easily.  The
default for @code{max-uuxqts} is 0, which means that there is no limit.
If HDB configuration files are being read and the code was compiled
without @code{HAVE_TAYLOR_CONFIG}, then if the file @file{Maxuuxqts} in
the configuration directory contains a readable number it will be used as
the value for @code{max-uuxqts}.

@item run-uuxqt @var{string} or @var{number}
@findex run-uuxqt

Specify when @code{uuxqt} should be run by @code{uucico}.  This may be a
positive number, in which case @code{uucico} will start a @code{uuxqt}
process whenever it receives the given number of execution files from
the remote system, and, if necessary, at the end of the call.  The
argument may also be one of the strings @samp{once}, @samp{percall}, or
@samp{never}.  The string @samp{once} means that @code{uucico} will
start @code{uuxqt} once at the end of execution.  The string
@samp{percall} means that @code{uucico} will start @code{uuxqt} once per
call that it makes (this is only different from @code{once} when
@code{uucico} is invoked in a way that causes it to make multiple calls,
such as when the @samp{-r1} argument is used without the @samp{-s}
argument).  The string @samp{never} means that @code{uucico} will never
start @code{uuxqt}, in which case @code{uuxqt} should be periodically
run via some other mechanism.  The default depends upon which type of
configuration files are being used; if @code{HAVE_TAYLOR_CONFIG} is used
the default is @samp{once}, otherwise if @code{HAVE_HDB_CONFIG} is used
the default is @samp{percall}, and otherwise, for @code{HAVE_V2_CONFIG},
the default is @samp{10}.

@item timetable @var{string} @var{string}
@findex timetable

The @code{timetable} defines a timetable that may be used in
subsequently appearing time strings; @ref{Time Strings}.  The first
string names the timetable entry; the second is a time string.

The following @code{timetable} commands are predefined.  The NonPeak
timetable is included for compatibility.  It originally described the
offpeak hours of Tymnet and Telenet, but both have since changed their
schedules.

@example
timetable Evening Wk1705-0755,Sa,Su
timetable Night Wk2305-0755,Sa,Su2305-1655
timetable NonPeak Wk1805-0655,Sa,Su
@end example

If this command does not appear, then obviously no additional timetables
will be defined.

@item v2-files @var{boolean}
@findex v2-files

If the code was compiled to be able to read V2 configuration files, a
false argument to this command will prevent them from being read.
This can be useful while testing.  The default is true.

@item hdb-files @var{boolean}
@findex hdb-files

If the code was compiled to be able to read HDB configuration files, a
false argument to this command will prevent them from being read.
This can be useful while testing.  The default is true.

@end table

@node Configuration File Names, Log File Names, Miscellaneous (config), config File
@subsection Configuration File Names

@table @code

@item sysfile @var{strings}
@findex sysfile

Specify the system file(s).  The default is the file @file{sys} in the
directory @var{newconfigdir}.  These files hold information about other
systems with which this system communicates; see @ref{sys File}.
Multiple system files may be given on the line, and the @code{sysfile}
command may be repeated; each system file has its own set of defaults.

@item portfile @var{strings}
@findex portfile

Specify the port file(s).  The default is the file @file{port} in the
directory @var{newconfigdir}.  These files describe ports which are used
to call other systems and accept calls from other systems; see @ref{port
File}.  No port files need be named at all.  Multiple port files may be
given on the line, and the @code{portfile} command may be repeated.

@item dialfile @var{strings}
@findex dialfile

Specify the dial file(s).  The default is the file @file{dial} in the
directory @var{newconfigdir}.  These files describe dialing devices
(modems); @xref{dial File}.  No dial files need be named at all.
Multiple dial files may be given on the line, and the @code{dialfile}
command may be repeated.

@item dialcodefile @var{strings}
@findex dialcodefile
@cindex configuration file (dialcode)
@cindex dialcode file
@cindex dialcode configuration file

Specify the dialcode file(s).  The default is the file @file{dialcode}
in the directory @var{newconfigdir}.  These files specify dialcodes that
may be used when sending phone numbers to a modem.  This permits using
the same set of phone numbers in different area-codes or with different
phone systems, by using dialcodes to specify the calling sequence.  When
a phone number goes through dialcode translation, the leading alphabetic
characters are stripped off.  The dialcode files are read line by line,
just like any other configuration file, and when a line is found whose
first word is the same as the leading characters from the phone number,
the second word on the line (which would normally consist of numbers)
replaces the dialcode in the phone number.  No dialcode file need be
used.  Multiple dialcode files may be specified on the line, and the
@code{dialcodefile} command may be repeated; all the dialcode files will
be read in turn until a dialcode is located.

@item callfile @var{strings}
@findex callfile
@cindex call out file
@cindex call configuration file
@cindex call out login name
@cindex call out password
@cindex configuration file (call)

Specify the call out login name and password file(s).  The default is
the file @file{call} in the directory @var{newconfigdir}.  If the call
out login name or password for a system are given as @kbd{*}
(@pxref{Logging In}), these files are read to get the real login name or
password.  Each line in the file(s) has three words: the system name,
the login name, and the password.  The login name and password may
contain escape sequences like those in a chat script expect string
(@pxref{Chat Scripts}).  This file is only used when placing calls to
remote systems; the password file described under @code{passwdfile}
below is used for incoming calls.  The intention of the call out file is
to permit the system file to be publically readable; the call out files
must obviously be kept secure.  These files need not be used.  Multiple
call out files may be specified on the line, and the @code{callfile}
command may be repeated; all the files will be read in turn until the
system is found.

@item passwdfile @var{strings}
@findex passwdfile
@cindex passwd file
@cindex passwd configuration file
@cindex configuration file (passwd)
@cindex call in login name
@cindex call in password

Specify the password file(s) to use for login names when @code{uucico}
is doing its own login prompting, which it does when given the
@samp{-e}, @samp{-l} or @samp{-w} switches.  The default is the file
@file{passwd} in the directory @var{newconfigdir}.  Each line in the
file(s) has two words: the login name and the password (e.g. @code{Ufoo
foopas}).  They may contain escape sequences like those in a chat script
expect string (@pxref{Chat Scripts}).  The login name is accepted before
the system name is known, so these are independent of which system is
calling in; a particular login may be required for a system by using the
@code{called-login} command in the system file (@pxref{Accepting a
Call}).  These password files are optional, although one must exist if
@code{uucico} is to present its own login prompts.

As a special exception, a colon may be used to separate the login name
from the password, and a colon may be used to terminate the password.
This means that the login name and password may not contain a colon.
This feature, in conjunction with the @code{HAVE_ENCRYPTED_PASSWORDS}
macro in @file{policy.h}, permits using a standard Unix
@file{/etc/passwd} as a UUCP password file, providing the same set of
login names and passwords for both @code{getty} and @code{uucico}.

Multiple password files may be specified on the line, and the
@code{passwdfile} command may be repeated; all the files will be read in
turn until the login name is found.

@end table

@node Log File Names, Debugging Levels, Configuration File Names, config File
@subsection Log File Names

@table @code

@item logfile @var{string}
@findex logfile
@cindex log file

Name the log file.  The default is from @file{policy.h}.  Logging
information is written to this file.  If @code{HAVE_HDB_LOGGING} is
defined in @file{policy.h}, then by default a separate log file is used
for each system.  Using this command to name a log file will cause all
the systems to use it.

@item statfile @var{string}
@findex statfile
@cindex statistics file

Name the statistics file.  The default is from @file{policy.h}.
Statistical information about file transfers is written to this file.

@item debugfile @var{string}
@findex debugfile
@cindex debugging file

Name the file to which all debugging information is written.  The
default is from @file{policy.h}.  This command is only effective if the
code has been compiled to include debugging (this is controlled by the
@code{DEBUG} macro in @file{policy.h}).  If debugging is on, messages
written to the log file are also written to the debugging file to make
it easier to keep the order of actions straight.  The debugging file is
different from the log file because information such as passwords can
appear in it, so it must be not be publically readable.

@end table

@node Debugging Levels,  , Log File Names, config File
@subsection Debugging Levels

@table @code

@item debug @var{string} @dots{}
@findex debug in config file

Set the debugging level.  This command is only effective if the code has
been compiled to include debugging.  The default is to have no
debugging.  The arguments are strings which name the types of debugging
to be turned on.  The following types of debugging are defined:

@table @samp
@item abnormal
Output debugging messages for abnormal situations, such as recoverable errors.
@item chat
Output debugging messages for chat scripts.
@item handshake
Output debugging messages for the initial handshake.
@item uucp-proto
Output debugging messages for the UUCP session protocol.
@item proto
Output debugging messages for the individual link protocols.
@item port
Output debugging messages for actions on the communication port.
@item config
Output debugging messages while reading the configuration files.
@item spooldir
Output debugging messages for actions in the spool directory.
@item execute
Output debugging messages whenever another program is executed.
@item incoming
List all incoming data in the debugging file.
@item outgoing
List all outgoing data in the debugging file.
@item all
All of the above.
@end table

The debugging level may also be specified as a number.  A 1 will set
@samp{chat} debugging, a 2 will set both @samp{chat} and
@samp{handshake} debugging, and so on down the possibilities.  Currently
an 11 will turn on all possible debugging, since there are 11 types of
debugging messages listed above; more debugging types may be added in
the future.  The @code{debug} command may be used several times in the
configuration file; every debugging type named will be turned on.  When
running any of the programs, the @samp{-x} switch (actually, for
@code{uulog} it's the @samp{-X} switch) may be used to turn on
debugging.  The argument to the @samp{-x} switch is one of the strings
listed above, or a number as described above, or a comma separated list
of strings (e.g.  @samp{-x chat,handshake}).  The @samp{-x} switch may
also appear several times on the command line, in which case all named
debugging types will be turned on.  The @samp{-x} debugging is in
addition to any debugging specified by the @code{debug} command; there
is no way to cancel debugging information.  The debugging level may also
be set specifically for calls to or from a specific system with the
@code{debug} command in the system file (@pxref{Miscellaneous (sys)}).

The debugging messages are somewhat idiosyncratic; it may be necessary
to refer to the source code for additional information in some cases.

@end table

@node sys File, port File, config File, Configuration Files
@section The System Configuration File
@cindex sys file
@cindex system configuration file
@cindex configuration file (sys) 

By default there is a single system configuration, named @file{sys} in
the directory @var{newconfigdir}.  This may be overridden by the
@code{sysfile} command in the main configuration file; see
@ref{Configuration File Names}.

These files describe all remote systems known to the UUCP package.

@menu
* Defaults and Alternates::     Using defaults and alternates
* Naming the System::           Naming the system
* Calling Out::                 Calling out
* Accepting a Call::            Accepting a call
* Protocol Selection::          Protocol selection
* File Transfer Control::       File transfer control
* Miscellaneous (sys)::         Miscellaneous sys file commands
* Default sys File Values::     Default values
@end menu

@node Defaults and Alternates, Naming the System, sys File, sys File
@subsection Defaults and Alternates

The first set of commands in the file, up to the first @code{system}
command, specify defaults to be used for all systems in that file.  Each
@file{sys} file uses a different set of defaults.

Subsequently, each set of commands from @code{system} up to the next
@code{system} command describe a particular system.  Default values may
be overridden for specific systems.

Each system may then have a series of alternate choices to use when
calling out or calling in.  The first set of commands for a particular
system, up to the first @code{alternate} command, provide the first
choice.  Subsequently, each set of commands from @code{alternate} up to
the next @code{alternate} command describe an alternate choice for
calling out or calling in.

When a system is called, the commands before the first @code{alternate}
are used to select a phone number, port, and so forth; if the call fails
for some reason, the commands between the first @code{alternate} and the
second are used, and so forth.  Well, not quite.  Actually, each
succeeding alternate will only be used if it is different in some
relevant way (different phone number, different chat script, etc.).  If
you want to force the same alternate to be used again (to retry a phone
call more than once, for example), enter the phone number (or any other
relevant field) again to make it appear different.

The alternates can also be used to give different permissions to an
incoming call based on the login name.  This will only be done if the
first set of commands, before the first @code{alternate} command, uses
the @code{called-login} command.  The list of alternates will be
searched, and the first alternate with a matching @code{called-login}
command will be used.  If no alternates match, the call will be
rejected.

The @code{alternate} command may also be used in the file-wide defaults
(the set of commands before the first @code{system} command).  This
might be used to specify a list of ports which are available for all
systems (for an example of this, see @ref{Gateway Example}) or to
specify permissions based on the login name used by the remote system
when it calls in.  The first alternate for each system will default to
the first alternate for the file-wide defaults (as modified by the
commands used before the first @code{alternate} command for this
system), the second alternate for each system to the second alternate
for the file-wide defaults (as modified the same way), and so forth.  If
a system specifies more alternates than the file-wide defaults, the
trailing ones will default to the last file-wide default alternate.  If
a system specifies fewer alternates than the file-wide defaults, the
trailing file-wide default alternates will be used unmodified.  The
@code{default-alternates} command may be used to modify this behaviour.

This can all get rather confusing, although it's easier to use than to
describe concisely; the @code{uuchk} program may be used to ensure that
you are getting what you want.

@node Naming the System, Calling Out, Defaults and Alternates, sys File
@subsection Naming the System

@table @code

@item system @var{string}
@findex system

Specify the remote system name.  Subsequent commands up to the next
@code{system} command refer to this system.

@item alternate [@var{string}]
@findex alternate

Start an alternate set of commands (@pxref{Defaults and Alternates}).
An optional argument may be used to name the alternate.  This name will
be put in the log file if the alternate is used to call the system.
There is no way to name the first alternate (the commands before the
first @code{alternate} command).

@item default-alternates @var{boolean}
@findex default-alternates

If the argument is false, any remaining default alternates (from the
defaults specified at the top of the current system file) will not be
used.  The default is true.

@item alias @var{string}
@findex alias

Specify an alias for the current system.  The alias may be used by local
@code{uucp} and @code{uux} commands, as well as by the remote system
(which can be convenient if a remote system changes its name).  The
default is to have no aliases.

@item myname @var{string}
@findex myname

Specifies a different system name to use when calling the remote system.
Also, if @code{called-login} is used and is not @samp{ANY}, then, when a
system logs in with that login name, @var{string} is used as the local
system name.  Because the local system name must be determined before
the remote system has identified itself, using @code{myname} and
@code{called-login} together for any system will set the local name for
that login; this means that each locally used system name must have a
unique login name associated with it.  This allows a system to have
different names for an external and an internal network.  The default is
to not use a special local name.

@end table

@node Calling Out, Accepting a Call, Naming the System, sys File
@subsection Calling Out

This section describes commands used when placing a call to another
system.

@menu
* When to Call::                When to call
* Placing the Call::            Placing the call
* Logging In::                  Logging in
@end menu

@node When to Call, Placing the Call, Calling Out, Calling Out
@subsubsection When to Call

@table @code

@item time @var{string} [@var{number}]
@findex time

Specify when the system may be called.  The first argument is a time
string; see @ref{Time Strings}.  The optional second argument specifies
a retry time in minutes.  If a call made during a time that matches the
time string fails, no more calls are permitted until the retry time has
passed.  By default an exponentially increasing retry time is used:
after each failure the next retry period is longer.  A retry time
specified in the @code{time} command is always a fixed amount of time.

The @code{time} command may appear multiple times in a single alternate,
in which case if any time string matches the system may be called.  When
the @code{time} command is used for a particular system, any @code{time}
or @code{timegrade} commands that appeared in the system defaults are
ignored.

The default time string is @samp{Never}.

@item timegrade @var{character} @var{string} [@var{number}]
@findex timegrade

The @var{character} specifies a grade.  It must be a single letter or
digit.  The @var{string} is a time string (@pxref{Time Strings}).  All
jobs of grade @var{character} or higher (where @kbd{0} > @kbd{9} >
@kbd{A} > @kbd{Z} > @kbd{a} > @kbd{z}) may be run at the specified time.
An ordinary @code{time} command is equivalent to using @code{timegrade}
with a grade of @kbd{z}, permitting all jobs.  If there are no jobs of a
sufficiently high grade according to the time string, the system will
not be called.  Giving the @samp{-s} switch to @code{uucico} to force it
to call a system causes it to assume there is a job of grade @kbd{0}
waiting to be run.

The optional third argument specifies a retry time in minutes.  See the
@code{time} command, above, for more details.

Note that the @code{timegrade} command serves two purposes: 1) if there
is no job of sufficiently high grade the system will not be called, and
2) if the system is called anyway (because the @samp{-s} switch was
given to @code{uucico}) only jobs of sufficiently high grade will be
transferred.  However, if the other system calls in, the
@code{timegrade} commands are ignored, and jobs of any grade may be
transferred (but see @code{call-timegrade} below).  Also, the
@code{timegrade} command will not prevent the other system from
transferring any job it chooses, regardless of who placed the call.

The @code{timegrade} command may appear multiple times without using
@code{alternate}.  When the @code{timegrade} command is used for a
particular system, any @code{time} or @code{timegrade} commands that
appeared in the system defaults are ignored.

If this command does not appear, there are no restrictions on what grade
of work may be done at what time.

@item max-retries @var{number}
@findex max-retries

Gives the maximum number of times this system may be retried.  If this
many calls to the system fail, it will be called at most once a day
whatever the retry time is.  The default is 26.

@item success-wait @var{number}

A retry time, in seconds, which applies after a successful call.  This
can be used to put a limit on how frequently the system is called.  For
example, an argument of 1800 means that the system will not be called
more than once every half hour.  The default is 0, which means that
there is no limit.

@item call-timegrade @var{character} @var{string}
@findex call-timegrade

The @var{character} is a single character @kbd{A} to @kbd{Z}, @kbd{a} to
@kbd{z}, or @kbd{0} to @kbd{9} and specifies a grade.  The @var{string}
is a time string as described under the @code{time} command.  If a call
is placed to the other system during a time which matches the time
string, the remote system will be requested to only run jobs of grade
@var{character} or higher.  Unfortunately, there is no way to guarantee
that the other system will obey the request (this UUCP package will, but
there are others which will not); moreover job grades are historically
somewhat arbitrary, so specifying a grade will only be meaningful if the
other system cooperates in assigning grades.  This grade restriction
only applies when the other system is called, not when the other system
calls in.

The @code{call-timegrade} command may appear multiple times without
using @code{alternate}.  If this command does not appear, or if none of
the time strings match, the remote system will be allowed to send
whatever grades of work it chooses.

@end table

@node Placing the Call, Logging In, When to Call, Calling Out
@subsubsection Placing the Call

@table @code

@itemx speed @var{number}
@findex speed in sys file
@item baud @var{number}
@findex baud in sys file

Specify the speed (the term @dfn{baud} is technically incorrect, but
widely understood) at which to call the system.  This will try all
available ports with that speed until an unlocked port is found.  The
ports are defined in the port file.  If both @code{speed} and
@code{port} commands appear, both are used when selecting a port.  To
allow calls at more than one speed, the @code{alternate} command must be
used (@pxref{Defaults and Alternates}).  If this command does not
appear, there is no default; the speed may be specified in the port
file, but if it is not then the natural speed of the port will be used
(whatever that means on the system).  Specifying an explicit speed of 0
will request the natural speed of the port (whatever the system sets it
to), overriding any default speed from the defaults at the top of the
file.

@item port @var{string}
@findex port in sys file

Name a particular port or type of port to use when calling the system.
The information for this port is obtained from the port file.  If this
command does not appear, there is no default; a port must somehow be
specified in order to call out (it may be specified implicitly using the
@code{speed} command or explicitly using the next version of
@code{port}).  There may be many ports with the same name; each will be
tried in turn until an unlocked one is found which matches the desired
speed.

@item port @var{string} @dots{}

If more than one string follows the @code{port} command, the strings are
treated as a command that might appear in the port file (@pxref{port
File}).  If a port is named (by using a single string following
@code{port}) these commands are ignored; their purpose is to permit
defining the port completely in the system file rather than always
requiring entries in two different files.  In order to call out, a port
must be specified using some version of the @code{port} command, or by
using the @code{speed} command to select ports from the port file.

@item phone @var{string}
@findex phone
@itemx address @var{string}
@findex address

Give a phone number to call (when using a modem port) or a remote host
to contact (when using a TCP or TLI port).  The commands @code{phone}
and @code{address} are equivalent; the duplication is intended to
provide a mnemonic choice depending on the type of port in use.

When used with a modem port, an @kbd{=} character in the phone number
means to wait for a secondary dial tone (although only some modems
support this); a @kbd{-} character means to pause while dialing for 1
second (again, only some modems support this).  If the system has more
than one phone number, each one must appear in a different alternate.
The @code{phone} command must appear in order to call out on a modem;
there is no default.

When used with a TCP port, the string names the host to contact.  It may
be a domain name or a numeric Internet address.  If no address is
specified, the system name is used.

When used with a TLI port, the string is treated as though it were an
expect string in a chat script, allowing the use of escape characters
(@pxref{Chat Scripts}).  The @code{dialer-sequence} command in the port
file may override this address (@pxref{port File}).

When used with a port that not a modem or TCP or TLI, this command is
ignored.

@end table

@node Logging In,  , Placing the Call, Calling Out
@subsubsection Logging In
@table @code

@item chat @var{strings}
@findex chat in sys file
@item chat-timeout @var{number}
@findex chat-timeout in sys file
@item chat-fail @var{string}
@findex chat-fail in sys file
@item chat-seven-bit @var{boolean}
@findex chat-seven-bit in sys file
@item chat-program @var{strings}
@findex chat-program in sys file

These commands describe a chat script to use when logging on to a remote
system.  Chat scripts are explained in @ref{Chat Scripts}.

Two additional escape sequences may be used in send strings.

@table @samp
@item \L
Send the login name, as set by the @code{call-login} command.
@item \P
Send the password, as set by the @code{call-password} command.
@end table

Three additional escape sequences may be used with the
@code{chat-program} command.  These are @samp{\L} and @samp{\P}, which
become the login name and password, respectively, and @samp{\Z}, which
becomes the name of the system of being called.

The default chat script is:

@example
chat "" \r\c ogin:-BREAK-ogin:-BREAK-ogin: \L word: \P
@end example

This will send a carriage return (the @kbd{\c} suppresses the additional
trailing carriage return that would otherwise be sent) and waits for the
string @samp{ogin:} (which would be the last part of the @samp{login:}
prompt supplied by a Unix system).  If it doesn't see @samp{ogin:}, it
sends a break and waits for @samp{ogin:} again.  If it still doesn't see
@samp{ogin:}, it sends another break and waits for @samp{ogin:} again.
If it still doesn't see @samp{ogin:}, the chat script aborts and hangs
up the phone.  If it does see @samp{ogin:} at some point, it sends the
login name (as specified by the @code{call-login} command) followed by a
carriage return (since all send strings are followed by a carriage
return unless @kbd{\c} is used) and waits for the string @samp{word:}
(which would be the last part of the @samp{Password:} prompt supplied by
a Unix system).  If it sees @samp{word:}, it sends the password and a
carriage return, completing the chat script.  The program will then
enter the handshake phase of the UUCP protocol.

This chat script will work for most systems, so you will only be
required to use the @code{call-login} and @code{call-password} commands.
In fact, in the file-wide defaults you could set defaults of
@samp{call-login *} and @samp{call-password *}; you would then just have
to make an entry for each system in the call-out login file.

Some systems seem to flush input after the @samp{login:} prompt, so they
may need a version of this chat script with a @kbd{\d} before the
@kbd{\L}.  When using UUCP over TCP, some servers will not be handle the
initial carriage return sent by this chat script; in this case you may
have to specify the simple chat script @samp{ogin: \L word: \P}.

@item call-login @var{string}
@findex call-login

Specify the login name to send with @kbd{\L} in the chat script.  If the
string is @samp{*} (e.g. @samp{call-login *}) the login name will be
fetched from the call out login name and password file
(@pxref{Configuration File Names}).  The string may contain escape
sequences as though it were an expect string in a chat script
(@pxref{Chat Scripts}).  There is no default.

@item call-password @var{string}
@findex call-password

Specify the password to send with @kbd{\P} in the chat script.  If the
string is @samp{*} (e.g. @samp{call-password *}) the password will be
fetched from the call-out login name and password file
(@pxref{Configuration File Names}).  The string may contain escape
sequences as though it were an expect string in a chat script
(@pxref{Chat Scripts}).  There is no default.

@end table

@node Accepting a Call, Protocol Selection, Calling Out, sys File
@subsection Accepting a Call

@table @code

@item called-login @var{strings}
@findex called-login

The first @var{string} specifies the login name that the system must use
when calling in.  If it is @samp{ANY} (e.g. @samp{called-login ANY}) any
login name may be used; this is useful to override a file-wide default
and to indicate that future alternates may have different login names.
Case is significant.  The default value is @samp{ANY}.  

Different alternates (@pxref{Defaults and Alternates}) may use different
@code{called-login} commands, in which case the login name will be used
to select which alternate is in effect; this will only work if the first
alternate (before the first @code{alternate} command) uses the
@code{called-login} command.

Additional strings may be specified after the login name; they are a
list of which systems are permitted to use this login name.  If this
feature is used, then normally the login name will only be given in a
single @code{called-login} command.  Only systems which appear on the
list, or which use an explicit @code{called-login} command, will be
permitted to use that login name.  If the same login name is used more
than once with a list of systems, all the lists are concatenated
together.  This feature permits you to restrict a login name to a
particular set of systems without requiring you to use the
@code{called-login} command for every single system; you can achieve a
similar effect by using a different system file for each permitted login
name with an appropriate @code{called-login} command in the file-wide
defaults.

@item callback @var{boolean}
@findex callback

If @var{boolean} is true, then when the remote system calls
@code{uucico} will hang up the connection and prepare to call it back.
The default is false.

@item called-chat @var{strings}
@findex called-chat
@item called-chat-timeout @var{number}
@findex called-chat-timeout
@item called-chat-fail @var{string}
@findex called-chat-fail
@item called-chat-seven-bit @var{boolean}
@findex called-chat-seven-bit
@item called-chat-program @var{strings}
@findex called-chat-program
  
These commands may be used to define a chat script (@pxref{Chat
Scripts}) that is run whenever the local system is called by the system
being defined.  The chat script defined by the @code{chat} command
(@pxref{Logging In}), on the other hand, is used when the remote system
is called.  This called chat script might be used to set special modem
parameters that are appropriate to a particular system.  It is run after
protocol negotiation is complete, but before the protocol has been
started.  See @ref{Logging In} for additional escape sequence which may
be used besides those defined for all chat scripts.  There is no default
called chat script.  If the called chat script fails, the incoming call
will be aborted.

@end table

@node Protocol Selection, File Transfer Control, Accepting a Call, sys File
@subsection Protocol Selection

@table @code

@item protocol @var{string}
@findex protocol in sys file

Specifies which protocols to use for the other system, and in which
order to use them.  This would not normally be used.  For example,
@samp{protocol tfg}.

The default depends on the characteristics of the port and the dialer,
as specified by the @code{seven-bit} and @code{reliable} commands.  If
neither the port nor the dialer use either of these commands, the
default is to assume an eight-bit reliable connection.  The commands
@samp{seven-bit true} or @samp{reliable false} might be used in either
the port or the dialer to change this.  Each protocol has particular
requirements that must be met before it will be considered during
negotiation with the remote side.

The @samp{t} and @samp{e} protocols are intended for use over TCP or
some other communication path with end to end reliability, as they do no
checking of the data at all.  They will only be considered on a TCP port
which is both reliable and eight bit.

The @samp{i} protocol is a bidirectional protocol.  It requires an
eight-bit connection.  It will run over a half-duplex link, such as
Telebit modems in PEP mode, but for efficient use of such a connection
you must use the @code{half-duplex} command (@pxref{port File}).

The @samp{g} protocol is robust, but requires an eight-bit connection.

The @samp{G} protocol is the System V Release 4 version of the @samp{g}
protocol.

The @samp{a} protocol is a Zmodem like protocol, contributed by Doug
Evans.  It requires an eight-bit connection, but unlike the @samp{g} or
@samp{i} protocol it will work if certain control characters may not be
transmitted.

The @samp{j} protocol is a variant of the @samp{i} protocol which can
avoid certain control characters.  The set of characters it avoids can
be set by a parameter.  While it technically does not require an eight
bit connection (it could be configured to avoid all characters with the
high bit set) it would be very inefficient to use it over one.  It is
useful over a eight-bit connection that will not transmit certain
control characters.

The @samp{f} protocol is intended for use with X.25 connections; it
checksums each file as a whole, so any error causes the entire file to
be retransmitted.  It requires a reliable connection, but only uses
seven-bit transmissions.  It is a streaming protocol, so, while it can
be used on a serial port, the port must be completely reliable and flow
controlled; many aren't.

The @samp{v} protocol is the @samp{g} protocol as used by the DOS
program UUPC/Extended.  It is provided only so that UUPC/Extended users
can use it; there is no particular reason to select it.

The protocols will be considered in the order shown above.  This means
that if neither the @code{seven-bit} nor the @code{reliable} command are
used, the @samp{t} protocol will be used over a TCP connection and the
@samp{i} protocol will be used over any other type of connection
(subject, of course, to what is supported by the remote system; it may
be assumed that all systems support the @samp{g} protocol).

Note that currently specifying both @samp{seven-bit true} and
@samp{reliable false} will not match any protocol.  If this occurs
through a combination of port and dialer specifications, you will have
to use the @code{protocol} command for the system or no protocol will be
selected at all (the only reasonable choice would be @samp{protocol f}).

A protocol list may also be specified for a port (@pxref{port File}),
but if there is a list for the system the list for the port is ignored.

@item protocol-parameter @var{character} @var{string} @dots{}
@findex protocol-parameter in sys file

@var{character} is a single character specifying a protocol.  The
remaining strings are a command specific to that protocol which will be
executed if that protocol is used.  A typical command is something like
@samp{window 7}.  The particular commands are protocol specific.

The @samp{i} protocol supports the following commands, all of which take
numeric arguments:

@table @code
@item window
The window size to request the remote system to use.  This must be
between 1 and 16 inclusive.  The default is 16.
@item packet-size
The packet size to request the remote system to use.  This must be
between 1 and 4095 inclusive.  The default is 1024.
@item remote-packet-size
If this is between 1 and 4095 inclusive, the packet size requested by
the remote system is ignored and this is used instead.  The default is
0, which means that the remote system's request is honored.
@item sync-timeout
The length of time, in seconds, to wait for a SYNC packet from the remote
system.  SYNC packets are exchanged when the protocol is started.  The
default is 10.
@item sync-retries
The number of times to retry sending a SYNC packet before giving up.
The default is 6.
@item timeout
The length of time, in seconds, to wait for an incoming packet before
sending a negative acknowledgement.  The default is 10.
@item retries
The number of times to retry sending a packet or a negative
acknowledgement before giving up and closing the connection.  The
default is 6.
@item errors
The maximum number of errors to permit before closing the connection.
The default is 100.
@item error-decay
The rate at which to ignore errors.  Each time this many packets are
received, the error count is decreased by one, so that a long connection
with an occasional error will not exceed the limit set by @code{errors}.
The default is 10.
@item ack-frequency
The number of packets to receive before sending an acknowledgement.  The
default is half the requested window size, which should provide good
performance in most cases.
@end table

The @samp{g}, @samp{G} and @samp{v} protocols support the following
commands, all of which take numeric arguments, except
@code{short-packets} which takes a boolean argument:

@table @code
@item window
The window size to request the remote system to use.  This must be
between 1 and 7 inclusive.  The default is 7.
@item packet-size
The packet size to request the remote system to use.  This must be a
power of 2 between 32 and 4096 inclusive.  The default is 64 for the
@samp{g} and @samp{G} protocols and 512 for the @samp{v} protocol.  Many
older UUCP packages do not support packet sizes larger than 64, and many
others do not support packet sizes larger than 128.  Some UUCP packages
will even dump core if a larger packet size is requested.  The packet
size is not a negotiation, and it may be different in each direction.
If you request a packet size larger than the remote system supports, you
will not be able to send any files.
@item startup-retries
The number of times to retry the initialization sequence.  The default
is 8.
@item init-retries
The number of times to retry one phase of the initialization sequence
(there are three phases).  The default is 4.
@item init-timeout
The timeout in seconds for one phase of the initialization sequence.  The
default is 10.
@item retries
The number of times to retry sending either a data packet or a request
for the next packet.  The default is 6.
@item timeout
The timeout in seconds when waiting for either a data packet or an
acknowledgement.  The default is 10.
@item garbage
The number of unrecognized bytes to permit before dropping the
connection.  This must be larger than the packet size.  The default is
10000.
@item errors
The number of errors (malformed packets, out of order packets, bad
checksums, or packets rejected by the remote system) to permit before
dropping the connection.  The default is 100.
@item error-decay
The rate at which to ignore errors.  Each time this many packets are
received, the error count is decreased by one, so that a long connection
with an occasional error will not exceed the limit set by @code{errors}.
The default is 10.
@item remote-window
If this is between 1 and 7 inclusive, the window size requested by the
remote system is ignored and this is used instead.  This can be useful
when dealing with some poor UUCP packages.  The default is 0, which
means that the remote system's request is honored.
@item remote-packet-size
If this is between 32 and 4096 inclusive the packet size requested by
the remote system is ignored and this is used instead.  There is
probably no good reason to use this.  The default is 0, which means that
the remote system's request is honored.
@item short-packets
If this is true, then the code will optimize by sending shorter packets
when there is less data to send.  This confuses some UUCP packages, such
as System V Release 4 (when using the @samp{G} protocol) and Waffle;
when connecting to such a package, this parameter must be set to false.
The default is true for the @samp{g} and @samp{v} protocols and false
for the @samp{G} protocol.
@end table

The @samp{a} protocol is a Zmodem like protocol contributed by Doug
Evans.  It supports the following commands, all of which take numeric
arguments except for @code{escape-control}, which takes a boolean
argument:

@table @code
@item timeout
Number of seconds to wait for a packet to arrive.  The default is 10.
@item retries
The number of times to retry sending a packet.  The default is 10.
@item startup-retries
The number of times to retry sending the initialization packet.  The
default is 4.
@item garbage
The number of garbage characters to accept before closing the
connection.  The default is 2400.
@item send-window
The number of characters that may be sent before waiting for an
acknowledgement.  The default is 1024.
@item escape-control
Whether to escape control characters.  If this is true, the protocol may
be used over a connection which does not transmit certain control
characters, such as @code{XON} or @code{XOFF}.  The connection must
still transmit eight bit characters other than control characters.  The
default is false.
@end table

The @samp{j} protocol can be used over an eight bit connection that will
not transmit certain control characters.  It accepts the same protocol
parameters that the @samp{i} protocol accepts, as well as one more:

@table @code
@item avoid
A list of characters to avoid.  This is a string which is interpreted as
an escape sequence (@pxref{Chat Scripts}).  The protocol does not have a
way to avoid printable ASCII characters (byte values from 32 to 126,
inclusive); only ASCII control characters and eight-bit characters may
be avoided.  The default value is @samp{\021\023}; these are the
characters @code{XON} and @code{XOFF} which many connections use for
flow control.  If the package is configured to use @code{HAVE_BSD_TTY},
then on some versions of Unix you may have to avoid @samp{\377} as well,
due to the way some implementations of the BSD terminal driver handle
signals.
@end table

The @samp{f} protocol is intended for use with error-correcting modems
only; it checksums each file as a whole, so any error causes the entire
file to be retransmitted.  It supports the following commands, both of
which take numeric arguments:

@table @code
@item timeout
The timeout in seconds before giving up.  The default is 120.
@item retries
How many times to retry sending a file.  The default is 2.
@end table

The @samp{t} and @samp{e} protocols are intended for use over TCP or
some other communication path with end to end reliability, as they do no
checking of the data at all.  They both support a single command, which
takes a numeric argument:

@table @code
@item timeout
The timeout in seconds before giving up.  The default is 120.
@end table

The protocol parameters are reset to their default values after each
call.

@end table

@node File Transfer Control, Miscellaneous (sys), Protocol Selection, sys File
@subsection File Transfer Control

@table @code

@item send-request @var{boolean}
@findex send-request

The @var{boolean} determines whether the remote system is permitted to
request files from the local system.  The default is yes.

@item receive-request @var{boolean}
@findex receive-request

The @var{boolean} determines whether the remote system is permitted to
send files to the local system.  The default is yes.

@item request @var{boolean}
@findex request

A shorthand command, equivalent to specifying both @samp{send-request
@var{boolean}} and @samp{receive-request @var{boolean}}.

@item call-transfer @var{boolean}
@findex call-transfer

The @var{boolean} is checked when the local system places the call.  It
determines whether the local system may do file transfers queued up for
the remote system.  The default is yes.

@item called-transfer @var{boolean}
@findex called-transfer

The @var{boolean} is checked when the remote system calls in.  It
determines whether the local system may do file transfers queued up for
the remote system.  The default is yes.

@item transfer @var{boolean}
@findex transfer

Equivalent to specifying both @samp{call-transfer @var{boolean}}
@samp{called-transfer @var{boolean}}.

@item call-local-size @var{number} @var{string}
@findex call-local-size

The @var{string} is a time string (@pxref{Time Strings}).  The
@var{number} is the size in bytes of the largest file that should be
transferred at a time matching the time string if the local system
placed the call and the request was made by the local system.  This
command may appear multiple times in a single alternate.  If this
command does not appear, or if none of the time strings match, there are
no size restrictions.

With all the size control commands, the size of a file from the remote
system (as opposed to a file from the local system) will only be checked
if the other system is running this package; other UUCP packages will
not understand a maximum size request, nor will they provide the size of
remote files.

@item call-remote-size @var{number} @var{string}
@findex call-remote-size

Specify the size in bytes of the largest file that should be
transferred at a given time by remote request when the local system
placed the call.  This command may appear multiple times in a single
alternate.  If this command does not appear, there are no size
restrictions.

@item called-local-size @var{number} @var{string}
@findex called-local-size

Specify the size in bytes of the largest file that should be transferred
at a given time by local request when the remote system placed the call.
This command may appear multiple times in a single alternate. If this
command does not appear, there are no size restrictions.

@item called-remote-size @var{number} @var{string}
@findex called-remote-size

Specify the size in bytes of the largest file that should be transferred
at a given time by remote request when the remote system placed the
call.  This command may appear multiple times in a single alternate. If
this command does not appear, there are no size restrictions.

@item local-send @var{strings}
@findex local-send

Specifies that files in the directories named by the @var{strings} may
be sent to the remote system when requested locally (using @code{uucp}
or @code{uux}).  The directories in the list should be separated by
whitespace.  A @kbd{~} may be used for the public directory.  On a Unix
system, this is typically @file{/usr/spool/uucppublic}; the public
directory may be set with the @code{pubdir} command.  Here is an example
of @code{local-send}:

@example
local-send ~ /usr/spool/ftp/pub
@end example

Listing a directory allows all files within the directory and all
subdirectories to be sent.  Directories may be excluded by preceding
them with an exclamation point.  For example:

@example
local-send /usr/ftp !/usr/ftp/private ~
@end example

@noindent
means that all files in @file{/usr/ftp} or the public directory may be
sent, except those files in @file{/usr/ftp/private}.  The list of
directories is read from left to right, and the last directory to apply
takes effect; this means that directories should be listed from top
down.  The default is the root directory (i.e., any file at all may be
sent by local request).

@item remote-send @var{strings}
@findex remote-send

Specifies that files in the named directories may be sent to the remote
system when requested by the remote system.  The default is @kbd{~}.

@item local-receive @var{strings}
@findex local-receive

Specifies that files may be received into the named directories when
requested by a local user.  The default is @kbd{~}.

@item remote-receive @var{strings}
@findex remote-receive

Specifies that files may be received into the named directories when
requested by the remote system.  The default is @kbd{~}.  On Unix, the
remote system may only request that files be received into directories
that are writeable by the world, regardless of how this is set.

@item forward-to @var{strings}
@findex forward-to

Specifies a list of systems to which files may be forwarded.  The remote
system may forward files through the local system on to any of the
systems in this list.  The string @samp{ANY} may be used to permit
forwarding to any system.  The default is to not permit forwarding to
other systems.  Note that if the remote system is permitted to execute
the @code{uucp} command, it effectively has the ability to forward to
any system.

@item forward-from @var{strings}
@findex forward-from

Specifies a list of systems from which files may be forwarded.  The
remote system may request files via the local system from any of the
systems in this list.  The string @samp{ANY} may be used to permit
forwarding to any system.  The default is to not permit forwarding from
other systems.  Note that if a remote system is permitted to execute the
@code{uucp} command, it effectively has the ability to request files
from any system.

@item forward @var{strings}
@findex forward

Equivalent to specifying both @samp{forward-to @var{strings}} and
@samp{forward-from @var{strings}}.  This would normally be used rather
than either of the more specific commands.

@end table

@node Miscellaneous (sys), Default sys File Values, File Transfer Control, sys File
@subsection Miscellaneous sys File Commands

@table @code

@item sequence @var{boolean}
@findex sequence

If @var{boolean} is true, then conversation sequencing is automatically
used for the remote system, so that if somebody manages to spoof as the
remote system, it will be detected the next time the remote system
actually calls.  This is false by default.

@item command-path @var{string}
@findex command-path

Specifies the path (a list of whitespace separated directories) to be
searched to locate commands to execute.  This is only used for commands
requested by @code{uux}, not for chat programs.  The default is from
@file{policy.h}.

@item commands @var{strings}
@findex commands

The list of commands which the remote system is permitted to execute
locally.  For example: @samp{commands rnews rmail}.  If the value is
@samp{ALL} (case significant), all commands may be executed.  The
default is @samp{rnews rmail}.

@item free-space @var{number}
@findex free-space

Specify the minimum amount of file system space (in bytes) to leave free
after receiving a file.  If the incoming file will not fit, it will be
rejected.  This initial rejection will only work when talking to another
instance of this package, since older UUCP packages do not provide the
file size of incoming files.  Also, while a file is being received,
@code{uucico} will periodically check the amount of free space.  If it
drops below the amount given by the @code{free-space} command, the file
transfer will be aborted.  The default amount of space to leave free is
from @file{policy.h}.  This file space checking may not work on all
systems.

@item pubdir @var{string}
@findex pubdir in sys file

Specifies the public directory that is used when @kbd{~} is specifed in
a file transfer or a list of directories.  This essentially overrides
the public directory specified in the main configuration file for this
system only.  The default is the public directory specified in the main
configuration file (which defaults to a value from @file{policy.h}).

@item debug @var{string} @dots{}
@findex debug in sys file

Set additional debugging for calls to or from the system.  This may be
used to debug a connection with a specific system.  It is particularly
useful when debugging incoming calls, since debugging information will
be generated whenever the call comes in.  See the @code{debug} command
in the main configuration file (@pxref{Debugging Levels}) for more
details.  The debugging information specified here is in addition to
that specified in the main configuration file or on the command line.

@item max-remote-debug @var{string} @dots{}
@findex max-remote-debug

When the system calls in, it may request that the debugging level be set
to a certain value.  This command may be used to put a limit on the
debugging level which the system may request, to avoid filling up the
disk with debugging information.  Only the debugging types named in the
@code{max-remote-debug} command may be turned on by the remote system.
To prohibit any debugging, use @samp{max-remote-debug none}.

@end table

@node Default sys File Values,  , Miscellaneous (sys), sys File
@subsection Default sys File Values

The following are used as default values for all systems; they can be
considered as appearing before the start of the file.

@example
time Never
chat "" \r\c ogin:-BREAK-ogin:-BREAK-ogin: \L word: \P
chat-timeout 10
callback n
sequence n
request y
transfer y
local-send /
remote-send ~
local-receive ~
remove-receive ~
command-path [ from @file{policy.h} ]
commands rnews rmail
max-remote-debug abnormal,chat,handshake
@end example

@node port File, dial File, sys File, Configuration Files
@section The Port Configuration File
@cindex port file
@cindex port configuration file
@cindex configuration file (port)

The port files may be used to name and describe ports.  By default there
is a single port file, named @file{port} in the directory
@var{newconfigdir}.  This may be overridden by the @code{portfile}
command in the main configuration file; see @ref{Configuration File
Names}.

Any commands in a port file before the first @code{port} command specify
defaults for all ports in the file; however, since the @code{type}
command must appear before all other commands for a port, the defaults
are only useful if all ports in the file are of the same type (this
restriction may be lifted in a later version).  All commands after a
@code{port} command up to the next @code{port} command then describe
that port.  There are different types of ports; each type supports its
own set of commands.  Each command indicates which types of ports
support it.  There may be many ports with the same name; if a system
requests a port by name then each port with that name will be tried
until an unlocked one is found.

@table @code

@item port @var{string}
@findex port in port file

Introduces and names a port.

@item type @var{string}
@findex type

Define the type of port.  The default is @samp{modem}.  If this command
appears, it must immediately follow the @code{port} command.  The type defines
what commands are subsequently allowed.  Currently the types are:

@table @samp
@item modem
For a modem hookup.
@item stdin
For a connection through standard input and standard output, as when
@code{uucico} is run as a login shell.
@item direct
For a direct connection to another system.
@item tcp
For a connection using TCP.
@item tli
For a connection using TLI.
@item pipe
For a connection through a pipe running another program.
@end table

@item protocol @var{string}
@findex protocol in port file

Specify a list of protocols to use for this port.  This is just like the
corresponding command for a system (@pxref{Protocol Selection}).  A
protocol list for a system takes precedence over a list for a port.

@item protocol-parameter @var{character} @var{strings} [ any type ]
@findex protocol-parameter in port file

The same command as the @code{protocol-parameter} command used for
systems (@pxref{Protocol Selection}).  This one takes precedence.

@item seven-bit @var{boolean} [ any type ]
@findex seven-bit in port file

This is only used during protocol negotiation; if the argument is true,
it forces the selection of a protocol which works across a seven-bit
link.  It does not prevent eight bit characters from being transmitted.
The default is false.

@item reliable @var{boolean} [ any type ]
@findex reliable in port file

This is only used during protocol negotiation; if the argument is
false, it forces the selection of a protocol which works across
an unreliable communication link.  The default is true.  It would
be more common to specify this for a dialer rather than a port.

@item half-duplex @var{boolean} [ any type ]
@findex half-duplex in port file

If the argument is true, it means that the port only supports
half-duplex connections.  This only affects bidirectional protocols, and
causes them to not do bidirectional transfers.

@item device @var{string} [ modem, direct and tli only ]
@findex device

Names the device associated with this port.  If the device is not named,
the port name is taken as the device.  Device names are system
dependent.  On Unix, a modem or direct connection might be something
like @file{/dev/ttyd0}; a TLI port might be @file{/dev/inet/tcp}.

@itemx speed @var{number} [modem and direct only ]
@findex speed in port file
@item baud @var{number} [ modem and direct only ]
@findex baud in port file

The speed this port runs at.  If a system specifies a speed but no port
name, then all ports which match the speed will be tried in order.  If
the speed is not specified here and is not specified by the system, the
natural speed of the port will be used by default.

@itemx speed-range @var{number} @var{number} [ modem only ]
@findex speed-range
@item baud-range @var{number} @var{number} [ modem only ]
@findex baud-range

Specify a range of speeds this port can run at.  The first number is the
minimum speed, the second number is the maximum speed.  These numbers
will be used when matching a system which specifies a desired speed.
The simple @code{speed} (or @code{baud}) command is still used to
determine the speed to run at if the system does not specify a speed.
For example, the command @samp{speed-range 300 19200} means that the
port will match any system which uses a speed from 300 to 19200 baud
(and will use the speed specified by the system); this could be combined
with @samp{speed 2400}, which means that when this port is used with a
system that does not specify a speed, the port will be used at 2400
baud.

@item carrier @var{boolean} [ modem and direct only ]
@findex carrier in port file

The argument indicates whether the port supports carrier.  

If a modem port does not support carrier, the carrier detect signal will
never be required on this port, regardless of what the modem chat script
indicates.  The default for a modem port is true.

If a direct port supports carrier, the port will be set to expect
carrier whenever it is used.  The default for a direct port is false.

@item hardflow @var{boolean} [ modem and direct only ]
@findex hardflow

The argument indicates whether the port supports hardware flow control.
If it does not, hardware flow control will not be turned on for this
port.  The default is true.  Hardware flow control is only supported on
some systems.

@item dial-device @var{string} [ modem only ]
@findex dial-device

Dialing instructions should be output to the named device, rather than
to the normal port device.  The default is to output to the normal port
device.

@item dialer @var{string} [ modem only ]
@findex dialer in port file

Name a dialer to use.  The information is looked up in the dial file.
There is no default.  Some sort of dialer information must be specified
to call out on a modem.

@item dialer @var{string} @dots{} [ modem only ]

Execute a dialer command.  If a dialer is named (by using the first form
of this command, described just above), these commands are ignored.
They may be used to specify dialer information directly in simple
situations without needing to go to a separate file.  There is no
default.  Some sort of dialer information must be specified to call out
on a modem.

@item dialer-sequence @var{strings} [ modem or tcp or tli only ]
@findex dialer-sequence

Name a sequence of dialers and tokens (phone numbers) to use.  The first
argument names a dialer, and the second argument names a token.  The
third argument names another dialer, and so on.  If there are an odd
number of arguments, the phone number specified with a @code{phone}
command in the system file is used as the final token.  The token is
what is used for @kbd{\D} or @kbd{\T} in the dialer chat script.  If the
token in this string is @kbd{\D}, the system phone number will be used;
if it is @kbd{\T}, the system phone number will be used after undergoing
dialcodes translation.  A missing final token is taken as @kbd{\D}.

This command currently does not work if @code{dial-device} is specified;
to handle this correctly will require a more systematic notion of chat
scripts.  Moreover, the @code{complete} and @code{abort} chat scripts,
the protocol parameters, and the @code{carrier} and @code{dtr-toggle}
commands are ignored for all but the first dialer.

This command basically lets you specify a sequence of chat scripts to
use.  For example, the first dialer might get you to a local network and
the second dialer might describe how to select a machine from the local
network.  This lets you break your dialing sequence into simple modules,
and may make it easier to share dialer entries between machines.

This command is to only way to use a chat script with a TCP port.  This
can be useful when using a modem which is accessed via TCP.

When this command is used with a TLI port, then if the first dialer is
@samp{TLI} or @samp{TLIS} the first token is used as the address to
connect to.  If the first dialer is something else, or if there is no
token, the address given by the @code{address} command is used
(@pxref{Placing the Call}).  Escape sequences in the address are
expanded as they are for chat script expect strings (@pxref{Chat
Scripts}).  The different between @samp{TLI} and @samp{TLIS} is that the
latter implies the command @samp{stream true}.  These contortions are
all for HDB compatibility.  Any subsequent dialers are treated as they
are for a TCP port.

@item lockname @var{string} [ modem and direct only ]
@findex lockname

Give the name to use when locking this port.  On Unix, this is the name
of the file that will be created in the lock directory.  It is used as
is, so on Unix it should generally start with @samp{LCK..}.  For
example, if a single port were named both @file{/dev/ttycu0} and
@file{/dev/tty0} (perhaps with different characteristics keyed on the
minor device number), then the command @code{lockname LCK..ttycu0} could
be used to force the latter to use the same lock file name as the
former.

@item service @var{string} [ tcp only ]
@findex service

Name the TCP port number to use.  This may be a number.  If not, it will
be looked up in @file{/etc/services}.  If this is not specified, the
string @samp{uucp} is looked up in @file{/etc/services}.  If it is not
found, port number 540 (the standard UUCP-over-TCP port number) will be
used.

@item push @var{strings} [ tli only ]
@findex push

Give a list of modules to push on to the TLI stream.

@item stream @var{boolean} [ tli only ]
@findex stream

If this is true, and the @code{push} command was not used, the
@samp{tirdwr} module is pushed on to the TLI stream.

@item server-address @var{string} [ tli only ]
@findex server-address

Give the address to use when running as a TLI server.  Escape sequences
in the address are expanded as they are for chat script expect strings
(@pxref{Chat Scripts}).

@item command @var{strings} [ pipe only ]
@findex command

Give the command, with arguments, to run when using a pipe port type.
When a port of this type is used, the command is executed and uucico
communicates with it over a pipe.  This permits uucico or cu to
communicate with another system which can only be reached through some
unusual means.  A sample use might be @samp{command /bin/rlogin -E -8 -l
@var{login} @var{system}}.  The command is run with the full privileges
of UUCP; it is responsible for maintaining security.

@end table

@node dial File, Security, port File, Configuration Files
@section The Dialer Configuration File
@cindex dial file
@cindex dialer configuration file
@cindex configuration file (dial)

The dialer configuration files define dialers.  By default there is a
single dialer file, named @file{dial} in the directory
@var{newconfigdir}.  This may be overridden by the @code{dialfile}
command in the main configuration file; see @ref{Configuration File
Names}.

Any commands in the file before the first @code{dialer} command specify
defaults for all the dialers in the file.  All commands after a
@code{dialer} command up to the next @code{dialer} command are
associated with the named dialer.

@table @code

@item dialer @var{string}
@findex dialer in dial file

Introduces and names a dialer.

@item chat @var{strings}
@findex chat in dial file
@item chat-timeout @var{number}
@findex chat-timeout in dial file
@item chat-fail @var{string}
@findex chat-fail in dial file
@item chat-seven-bit @var{boolean}
@findex chat-seven-bit in dial file
@item chat-program @var{strings}
@findex chat-program in dial file

Specify a chat script to be used to dial the phone.  See @ref{Chat
Scripts} for full details on chat scripts.

Taylor UUCP will sleep for one second between attempts to dial out on a
modem.  If your modem requires a longer wait period, you must start your
chat script with delays (@samp{\d} in a send string).

The chat script will be read from and sent to the port specified by the
@code{dial-device} command for the port, if there is one.

The following escape addition escape sequences may appear in send
strings:

@table @kbd
@item \D
send phone number without dialcode translation
@item \T
send phone number with dialcode translation
@item \M
do not require carrier
@item \m
require carrier (fail if not present)
@end table

See the description of the dialcodes file (@pxref{Configuration File
Names}) for a description of dialcode translation.  If the port does not
support carrier (as set by the @code{carrier} command in the port file)
@kbd{\M} and @kbd{\m} are ignored.  If both the port and the dialer
support carrier (as set by the @code{carrier} command in the port file
and the @code{carrier} command in the dialer file), then every chat
script implicitly begins with @kbd{\M} and ends with @kbd{\m}.  There is
no default chat script for dialers.

The following additional escape sequences may be used in
@code{chat-program}:

@table @kbd
@item \D
phone number without dialcode translation
@item \T
phone number with dialcode translation
@end table

If the program changes the port in any way (e.g., sets parity) the
changes will be preserved during protocol negotiation, but once the
protocol is selected it will change the port settings.

@item dialtone @var{string}
@findex dialtone

A string to output when dialing the phone number which causes the modem
to wait for a secondary dial tone.  This is used to translate the
@kbd{=} character in a phone number.  The default is a comma.

@item pause @var{string}
@findex pause

A string to output when dialing the phone number which causes the modem
to wait for 1 second.  This is used to translate the @kbd{-} character
in a phone number.  The default is a comma.

@item carrier @var{boolean}
@findex carrier in dial file

If the argument is true, the dialer supports the modem carrier signal.
After the phone number is dialed, @code{uucico} will require that
carrier be on.  One some systems, it will be able to wait for it.  If
the argument is false, carrier will not be required.  The default is
true.

@item carrier-wait @var{number}
@findex carrier-wait

If the port is supposed to wait for carrier, this may be used to
indicate how many seconds to wait.  The default is 60 seconds.  Only
some systems support waiting for carrier.

@item dtr-toggle @var{boolean} @var{boolean}
@findex dtr-toggle

If the first argument is true, then DTR is toggled before using
the modem.  This is only supported on some systems and some ports.  The
second @var{boolean} need not be present; if it is, and it is
true, the program will sleep for 1 second after toggling DTR.
The default is not to toggle DTR.

@item complete-chat @var{strings}
@findex complete-chat
@item complete-chat-timeout @var{number}
@findex complete-chat-timeout
@item complete-chat-fail @var{string}
@findex complete-chat-fail
@item complete-chat-seven-bit @var{boolean}
@findex complete-chat-seven-bit
@item complete-chat-program @var{strings}
@findex complete-chat-program

These commands define a chat script (@pxref{Chat Scripts}) which is run
when a call is finished normally.  This allows the modem to be reset.
There is no default.  No additional escape sequences may be used.

@item complete @var{string}
@findex complete

This is a simple use of @code{complete-chat}.  It is equivalent to
@code{complete-chat "" @var{string}}; this has the effect of sending
@var{string} to the modem when a call finishes normally.

@item abort-chat @var{strings}
@findex abort-chat
@item abort-chat-timeout @var{number}
@findex abort-chat-timeout
@item abort-chat-fail @var{string}
@findex abort-chat-fail
@item abort-chat-seven-bit @var{boolean}
@findex abort-chat-seven-bit
@item abort-chat-program @var{strings}
@findex abort-chat-program

These commands define a chat script (@pxref{Chat Scripts}) to be run
when a call is aborted.  They may be used to interrupt and reset the
modem.  There is no default.  No additional escape sequences may be
used.

@item abort @var{string}
@findex abort

This is a simple use of @code{abort-chat}.  It is equivalent to
@code{abort-chat "" @var{string}}; this has the effect of sending
@var{string} to the modem when a call is aborted.

@item protocol-parameter @var{character} @var{strings}
@findex protocol-parameter in dial file

Set protocol parameters, just like the @code{protocol-parameter} command
in the system configuration file or the port configuration file; see
@ref{Protocol Selection}.  These parameters take precedence, then those
for the port, then those for the system.

@item seven-bit @var{boolean}
@findex seven-bit in dial file

This is only used during protocol negotiation; if it is true, it
forces selection of a protocol which works across a seven-bit link.  It
does not prevent eight bit characters from being transmitted.  The
default is false.  It would be more common to specify this for a
port than for a dialer.

@item reliable @var{boolean}
@findex reliable in dial file

This is only used during protocol negotiation; if it is false, it
forces selection of a protocol which works across an unreliable
communication link.  The default is true.

@item half-duplex @var{boolean} [ any type ]
@findex half-duplex in dial file

If the argument is true, it means that the dialer only supports
half-duplex connections.  This only affects bidirectional protocols, and
causes them to not do bidirectional transfers.

@end table

@node Security,  , dial File, Configuration Files
@section Security

This discussion of UUCP security applies only to Unix.  It is a bit
cursory; suggestions for improvement are solicited.

UUCP is traditionally not very secure.  Taylor UUCP addresses some
security issues, but is still far from being a secure system.

If security is very important to you, then you should not permit any
external access to your computer, including UUCP.  Any opening to the
outside world is a potential security risk.

By default Taylor UUCP provides few mechanisms to secure local users of
the system from each other.  You can allow increased security by putting
the owner of the UUCP programs (normally @code{uucp}) into a separate
group; the use of this is explained in the following paragraphs, which
refer to this separate group as @code{uucp-group}.

When the @code{uucp} program is invoked to copy a file to a remote
system, it will by default copy the file into the UUCP spool directory.
When the @code{uux} program is used, the @samp{-C} switch must be used
to copy the file into the UUCP spool directory.  In any case, once the
file has been copied into the spool directory, other local users will
not be able to access it.

When a file is requested from a remote system, UUCP will only permit it
to be placed in a directory which is writable by the requesting user.
The directory must also be writable by UUCP.  A local user can create a
directory with a group of @code{uucp-group} and set the mode to permit
group write access.  This will allow the file be requested without
permitting it to be viewed by any other user.

There is no provision for security for @code{uucp} requests (as opposed
to @code{uux} requests) made by a user on a remote system.  A file sent
over by a remote request may only be placed in a directory which is
world writable, and the file will be world readable and writable.  This
will permit any local user to destroy or replace the contents of the
file.  A file requested by a remote system must be world readable, and
the directory it is in must be world readable.  Any local user will be
able to examine, although not necessarily modify, the file before it is
sent.

There are some security holes and race conditions that apply to the
above discussion which I will not elaborate on.  They are not hidden
from anybody who reads the source code, but they are somewhat technical
and difficult (though scarcely impossible) to exploit.  Suffice it to
say that even under the best of conditions UUCP is not completely
secure.

For many sites, security from remote sites is a more important
consideration.  Fortunately, Taylor UUCP does provide some support in
this area.

The greatest security is provided by always dialing out to the other
site.  This prevents anybody from pretending to be the other site.  Of
course, only one side of the connection can do this.

If remote dialins must be permitted, then it is best if the dialin line
is used only for UUCP.  If this is the case, then you should create a
call-in password file (@pxref{Configuration File Names}) and let
@code{uucico} do its own login prompting.  For example, to let remote
sites log in on a port named @samp{entry} in the port file (@pxref{port
File}) you might invoke @samp{uucico -p entry}.  This would cause
@code{uucico} to enter an endless loop of login prompts and daemon
executions.  The advantage of this approach is that even if remote users
break into the system by guessing or learning the password, they will
only be able to do whatever @code{uucico} permits them to do.  They will
not be able to start a shell on your system.

If remote users can dial in and log on to your system, then you have a
security hazard more serious than that posed by UUCP.  But then, you
probably knew that already.

Once your system has connected with the remote UUCP, there is a fair
amount of control you can exercise.  You can use the @code{remote-send}
and @code{remote-receive} commands to control the directories the remote
UUCP can access.  You can use the @code{request} command to prevent the
remote UUCP from making any requests of your system at all; however, if
you do this it will not even be able to send you mail or news.  If you
do permit remote requests, you should be careful to restrict what
commands may be executed at the remote system's request.  The default is
@code{rmail} and @code{rnews}, which will suffice for most systems.

If different remote systems call in and they must be granted different
privileges (perhaps some systems are within the same organization and
some are not) then the @code{called-login} command should be used for
each system to require that they different login names.  Otherwise it
would be simple for a remote system to use the @code{myname} command and
pretend to be a different system.  The @code{sequence} command can be
used to detect when one system pretended to be another, but since the
sequence numbers must be reset manually after a failed handshake this
can sometimes be more trouble than it's worth.

@node Protocols, Hacking, Configuration Files, Top
@chapter UUCP protocol internals

A detailed description of how the various UUCP protocols work is posted
monthly to the newsgroups @samp{comp.mail.uucp}, @samp{news.answers} and
@samp{comp.answers}.  There is no need to read this information in order
to use Taylor UUCP.  It is intended for people who are interested in how
the UUCP code works.

@node Hacking, Acknowledgements, Protocols, Top
@chapter Hacking Taylor UUCP

This chapter provides the briefest of guides to the Taylor UUCP source
code itself.

@menu
* System Dependence::           System Dependence
* Naming Conventions::          Naming Conventions
* Patches::                     Patches
@end menu

@node System Dependence, Naming Conventions, Hacking, Hacking
@section System Dependence

The code is carefully segregated into a system independent portion and a
system dependent portion.  The system dependent code is in the
@file{unix} subdirectory, and also in the files @file{tcp.c},
@file{tli.c} and @file{sysh.unx} (also known as @file{sysdep.h}).

With the right configuration parameters, the system independent code
calls only ANSI C functions.  Some of the less common ANSI C functions
are also provided in the @file{lib} directory.  The replacement function
@code{strtol} in @file{lib/strtol.c} assumes that the characters @kbd{A}
to @kbd{F} and @kbd{a} to @kbd{f} appear in strictly sequential order.
The function @code{igradecmp} in @file{uuconf/grdcmp.c} assumes that the
upper and lower case letters appear in order.  Both assumptions are true
for ASCII and EBCDIC, but neither is guaranteed by ANSI C.  Disregarding
these caveats, I believe that the system independent portion of the code
is strictly conforming.

That's not too exciting, since all the work is done in the system
dependent code.  I think that this code can conform to POSIX 1003.1,
given the right compilation parameters.  I'm a bit less certain about
this, though.

The code is in use on a 16 bit segmented system with no function
prototypes, so I'm certain that all casts to long and pointers are done
when necessary.

@node Naming Conventions, Patches, System Dependence, Hacking
@section Naming Conventions

I use a modified Hungarian naming convention for my variables and
functions.  As with all naming conventions, the code is rather opaque if
you are not familiar with it, but becomes clear and easy to use with
time.

The first character indicates the type of the variable (or function
return value).  Sometimes additional characters are used.  I use the
following type prefixes:

@table @samp
@item a
array; the next character is the type of an element
@item b
byte or character
@item c
count of something
@item e
stdio FILE *
@item f
boolean
@item i
generic integer
@item l
double
@item o
file descriptor (as returned by open, creat, etc.)
@item p
generic pointer
@item q
pointer to structure
@item s
structure
@item u
void (function return values only)
@item z
character string
@end table

A generic pointer (@code{p}) is sometimes a @code{void *}, sometimes a
function pointer in which case the prefix is pf, and sometimes a pointer
to another type, in which case the next character is the type to which
it points (pf is overloaded).

An array of strings (@code{char *[]}) would be named @code{az} (array of
string).  If this array were passed to a function, the function
parameter would be named @code{paz} (pointer to array of string).

Note that the variable name prefixes do not necessarily indicate the
type of the variable.  For example, a variable prefixed with i may be
int, long or short.  Similarly, a variable prefixed with b may be a char
or an int; for example, the return value of getchar would be caught in
an int variable prefixed with b.

For a non-local variable (extern or file static), the first character
after the type prefix is capitalized.

Most static variables and functions use another letter after the type
prefix to indicate which module they come from.  This is to help
distinguish different names in the debugger.  For example, all static
functions in @file{protg.c}, the @samp{g} protocol source code, use a
module prefix of @samp{g}.  This isn't too useful, as a number of
modules use a module prefix of @samp{s}.

@node Patches,  , Naming Conventions, Hacking
@section Patches

I am always grateful for any patches sent in.  Much of the flexibility
and portability of the code is due to other people.  Please do not
hesitate to send me any changes you have found necessary or useful.

When sending a patch, please send the output of the Unix @code{diff}
program invoked with the @samp{-c} option (if you have the GNU version
of @code{diff}, use the @samp{-p} option).  Always invoke @code{diff}
with the original file first and the modified file second.

If your @code{diff} does not support @samp{-c} (or you don't have
@code{diff}), send a complete copy of the modified file (if you have
just changed a single function, you can just send the new version of the
function).  In particular, please do not send @code{diff} output without
the @samp{-c} option, as it is useless.

If you have made a number of changes, it is very convenient for me if
you send each change as a separate mail message.  Sometimes I will think
that one change is useful but another one is not.  If they are in
different messages it is much easier for me to apply one but not the
other.

I rarely apply the patches directly.  Instead I work my way through the
hunks and apply each one separately.  This ensures that the naming
remains consistent, and that I understand all the code.

If you can not follow all these rules, then don't.  But if you do, it
makes it more likely that I will incorporate your changes.  I am not
paid for my UUCP work, and my available time is unfortunately very
restricted.  The package is important to me, and I do what I can, but I
can not do all that I would like, much less all that everybody else
would like.

Finally, please do not be offended if I do not reply to messages for
some time, even a few weeks.  I am often behind on my mail, and if I
think your message deserves a considered reply I will often put it aside
until I have time to deal with it.

@node Acknowledgements, Index (concepts), Hacking, Top
@chapter Acknowledgements

This is a list of people who gave help or suggestions while I was
working on the Taylor UUCP project.  Appearance on this list does not
constitute endorsement of the program, particularly since some of the
comments were criticisms.  I've probably left some people off, and I
apologize for any oversight; it does not mean your contribution was
unappreciated.

@ifinfo
First of all, I would like to thank the people at Infinity Development
Systems (formerly AIRS, which lives on in the domain name, at least for
now) for permitting me to use their computers and @file{uunet} access.
I would also like to thank Richard Stallman @code{<rms@@gnu.ai.mit.edu>}
for founding the Free Software Foundation and John Gilmore
@code{<gnu@@cygnus.com>} for writing the initial version of gnuucp which
was a direct inspiration for this somewhat larger project.  Chip
Salzenberg @code{<chip@@tct.com>} has contributed many patches.
Franc,ois Pinard @code{<pinard@@iro.umontreal.ca>} tirelessly tested the
code and suggested many improvements.  He also put together the initial
version of this document.  Doug Evans contributed the zmodem protocol.
Marc Boucher @code{<marc@@CAM.ORG>} contributed the code supporting the
pipe port type.  Finally, Verbus M. Counts @code{<verbus@@westmark.com>}
and Centel Federal Systems, Inc. deserve special thanks, since they
actually paid me money to port this code to System III.
@end ifinfo
@iftex
First of all, I would like to thank the people at Infinity Development
Systems (formerly AIRS, which lives on in the domain name, at least for
now) for permitting me to use their computers and @file{uunet} access.
I would also like to thank Richard Stallman @code{<rms@@gnu.ai.mit.edu>}
for founding the Free Software Foundation and John Gilmore
@code{<gnu@@cygnus.com>} for writing the initial version of gnuucp which
was a direct inspiration for this somewhat larger project.  Chip
Salzenberg @code{<chip@@tct.com>} has contributed many patches.
@tex
Fran\c cois Pinard
@end tex
@code{<pinard@@iro.umontreal.ca>} tirelessly tested the code and
suggested many improvements.  He also put together the initial version
of this document.  Doug Evans contributed the zmodem protocol.  Marc
Boucher @code{<marc@@CAM.ORG>} contributed the code supporting the pipe
port type.  Finally, Verbus M. Counts @code{<verbus@@westmark.com>} and
Centel Federal Systems, Inc. deserve special thanks, since they actually
paid me money to port this code to System III.
@end iftex

In alphabetical order:

@example
"Earle F. Ake - SAIC" @code{<ake@@Dayton.SAIC.COM>}
@code{mra@@searchtech.com} (Michael Almond)
@code{cambler@@zeus.calpoly.edu} (Christopher J. Ambler)
Brian W. Antoine @code{<briana@@tau-ceti.isc-br.com>}
@code{jantypas@@soft21.s21.com} (John Antypas)
@code{james@@bigtex.cactus.org} (James Van Artsdalen)
@code{nba@@sysware.DK} (Niels Baggesen)
@code{uunet!hotmomma!sdb} (Scott Ballantyne)
Zacharias Beckman @code{<zac@@dolphin.com>}
@code{mike@@mbsun.ann-arbor.mi.us} (Mike Bernson)
@code{bob@@usixth.sublink.org} (Roberto Biancardi)
@code{statsci!scott@@coco.ms.washington.edu} (Scott Blachowicz)
@code{bag%wood2.cs.kiev.ua@@relay.ussr.eu.net} (Andrey G Blochintsev)
@code{spider@@Orb.Nashua.NH.US} (Spider Boardman)
Gregory Bond @code{<gnb@@bby.com.au>}
Marc Boucher @code{<marc@@CAM.ORG>}
@code{dean@@coplex.com} (Dean Brooks)
@code{jbrow@@radical.com} (Jim Brownfield)
@code{dave@@dlb.com} (Dave Buck)
@code{gordon@@sneaky.lonestar.org} (Gordon Burditt)
@code{dburr@@sbphy.physics.ucsb.edu} (Donald Burr)
@code{mib@@gnu.ai.mit.edu} (Michael I Bushnell)
Brian Campbell @code{<brianc@@quantum.on.ca>}
Andrew A. Chernov @code{<ache@@astral.msk.su>}
@code{mafc!frank@@bach.helios.de} (Frank Conrad)
Ed Carp @code{<erc@@apple.com>}
@code{mpc@@mbs.linet.org} (Mark Clements)
@code{verbus@@westmark.westmark.com} (Verbus M. Counts)
@code{cbmvax!snark.thyrsus.com!cowan} (John Cowan)
Bob Cunningham @code{<bob@@soest.hawaii.edu>}
@code{kdburg@@incoahe.hanse.de} (Klaus Dahlenburg)
Damon @code{<d@@exnet.co.uk>}
@code{hubert@@arakis.fdn.org} (Hubert Delahaye)
@code{markd@@bushwire.apana.org.au} (Mark Delany)
Allen Delaney @code{<allen@@brc.ubc.ca>}
@code{denny@@dakota.alisa.com} (Bob Denny)
@code{ssd@@nevets.oau.org} (Steven S. Dick)
@code{gert@@greenie.gold.sub.org} (Gert Doering)
@code{gemini@@geminix.in-berlin.de} (Uwe Doering)
Hans-Dieter Doll @code{<hd2@@Insel.DE>}
Mark W. Eichin @code{<eichin@@cygnus.com>}
Andrew Evans @code{<andrew@@airs.com>}
@code{dje@@cygnus.com} (Doug Evans)
Marc Evans @code{<marc@@synergytics.com>}
Dan Everhart @code{<dan@@dyndata.com>}
@code{kksys!kegworks!lfahnoe@@cs.umn.edu} (Larry Fahnoe)
@code{fenner@@jazz.psu.edu} (Bill Fenner)
@code{jaf@@inference.com} (Jose A. Fernandez)
"David J. Fiander" @code{<golem!david@@news.lsuc.on.ca>}
Thomas Fischer @code{<batman@@olorin.dark.sub.org>}
@code{louis@@marco.de} (Ju"rgen Fluk)
@code{erik@@eab.retix.com} (Erik Forsberg)
@code{andy@@scp.caltech.edu} (Andy Fyfe)
Lele Gaifax @code{<piggy@@idea.sublink.org>}
@code{Peter.Galbavy@@micromuse.co.uk}
@code{hunter@@phoenix.pub.uu.oz.au} (James Gardiner [hunter])
Terry Gardner @code{<cphpcom!tjg01>}
@code{ol@@infopro.spb.su} (Oleg Girko)
@code{jimmy@@tokyo07.info.com} (Jim Gottlieb)
Benoit Grange @code{<ben@@fizz.fdn.org>}
@code{elg@@elgamy.jpunix.com} (Eric Lee Green)
@code{ryan@@cs.umb.edu} (Daniel R. Guilderson)
@code{greg@@gagme.chi.il.us} (Gregory Gulik)
Richard H. Gumpertz @code{<rhg@@cps.com>}
Michael Haberler @code{<mah@@parrot.prv.univie.ac.at>}
Daniel Hagerty @code{<hag@@eddie.mit.edu>}
@code{jh@@moon.nbn.com} (John Harkin)
@code{guy@@auspex.auspex.com} (Guy Harris)
Petri Helenius @code{<pete@@fidata.fi>}
@code{gabe@@edi.com} (B. Gabriel Helou)
Bob Hemedinger @code{<bob@@dalek.mwc.com>}
Andrew Herbert @code{<andrew@@werple.pub.uu.oz.au>}
Peter Honeyman @code{<honey@@citi.umich.edu>}
@code{jhood@@smoke.marlboro.vt.us} (John Hood)
Bill Irwin @code{<bill@@twg.bc.ca>}
@code{pmcgw!personal-media.co.jp!ishikawa} (Chiaki Ishikawa)
@code{bei@@dogface.austin.tx.us} (Bob Izenberg)
@code{djamiga!djjames@@fsd.com} (D.J.James)
Rob Janssen @code{<cmgit!rob@@relay.nluug.nl>}
@code{harvee!esj} (Eric S Johansson)
Kevin Johnson @code{<kjj@@pondscum.phx.mcd.mot.com>}
Alan Judge @code{<aj@@dec4ie.IEunet.ie>}
@code{chris@@cj_net.in-berlin.de} (Christof Junge)
@code{tron@@Veritas.COM} (Ronald S. Karr)
Brendan Kehoe @code{<brendan@@cs.widener.edu>}
@code{warlock@@csuchico.edu} (John Kennedy)
@code{kersing@@nlmug.nl.mugnet.org} (Jac Kersing)
Gabor Kiss @code{<kissg@@sztaki.hu>}
@code{gero@@gkminix.han.de} (Gero Kuhlmann)
@code{rob@@pact.nl} (Rob Kurver)
@code{kent@@sparky.IMD.Sterling.COM} (Kent Landfield)
@code{lebaron@@inrs-telecom.uquebec.ca}  (Gregory LeBaron)
@code{karl@@sugar.NeoSoft.Com} (Karl Lehenbauer)
@code{alex@@hal.rhein-main.de} (Alexander Lehmann)
@code{merlyn@@digibd.com} (Merlyn LeRoy)
@code{clewis@@ferret.ocunix.on.ca} (Chris Lewis)
@code{gdonl@@ssi1.com} (Don Lewis)
@code{libove@@libove.det.dec.com} (Jay Vassos-Libove)
@code{bruce%blilly@@Broadcast.Sony.COM} (Bruce Lilly)
Ted Lindgreen @code{<tlindgreen@@encore.nl>}
@code{andrew@@cubetech.com} (Andrew Loewenstern)
"Arne Ludwig" @code{<arne@@rrzbu.hanse.de>}
Matthew Lyle @code{<matt@@mips.mitek.com>}
@code{djm@@eng.umd.edu} (David J. MacKenzie)
John R MacMillan @code{<chance!john@@sq.sq.com>}
Giles D Malet @code{<shrdlu!gdm@@provar.kwnet.on.ca>}
@code{mem@@mv.MV.COM} (Mark E. Mallett)
@code{pepe@@dit.upm.es} (Jose A. Manas)
@code{peter@@xpoint.ruessel.sub.org} (Peter Mandrella)
@code{martelli@@cadlab.sublink.org} (Alex Martelli)
W Christopher Martin @code{<wcm@@geek.ca.geac.com>}
Yanek Martinson @code{<yanek@@mthvax.cs.miami.edu>}
@code{jm@@aristote.univ-paris8.fr} (Jean Mehat)
@code{me@@halfab.freiburg.sub.org} (Udo Meyer)
@code{les@@chinet.chi.il.us} (Leslie Mikesell)
@code{mmitchel@@digi.lonestar.org} (Mitch Mitchell)
Emmanuel Mogenet @code{<mgix@@krainte.jpn.thomson-di.fr>}
@code{rmohr@@infoac.rmi.de} (Rupert Mohr)
Jason Molenda @code{<molenda@@sequent.com>}
@code{ianm@@icsbelf.co.uk} (Ian Moran)
@code{brian@@ilinx.wimsey.bc.ca} (Brian J. Murrell)
@code{service@@infohh.rmi.de} (Dirk Musstopf)
@code{lyndon@@cs.athabascau.ca} (Lyndon Nerenberg)
@code{rolf@@saans.north.de} (Rolf Nerstheimer)
@code{tom@@smart.bo.open.de} (Thomas Neumann)
@code{mnichols@@pacesetter.com}
Richard E. Nickle @code{<trystro!rick@@Think.COM>}
@code{stephan@@sunlab.ka.sub.org} (Stephan Niemz)
@code{nolan@@helios.unl.edu} (Michael Nolan)
david nugent @code{<david@@csource.oz.au>}
Jim O'Connor @code{<jim@@bahamut.fsc.com>}
Petri Ojala @code{<ojala@@funet.fi>}
@code{oneill@@cs.ulowell.edu} (Brian 'Doc' O'Neill)
@code{abekas!dragoman!mikep@@decwrl.dec.com} (Mike Park)
Tim Peiffer @code{peiffer@@cs.umn.edu}
@code{don@@blkhole.resun.com} (Don Phillips)
"Mark Pizzolato 415-369-9366" @code{<mark@@infocomm.com>}
John Plate @code{<plate@@infotek.dk>}
@code{dplatt@@ntg.com} (Dave Platt)
@code{eldorado@@tharr.UUCP} (Mark Powell)
Mark Powell @code{<mark@@inet-uk.co.uk>}
@code{pozar@@kumr.lns.com} (Tim Pozar)
@code{putsch@@uicc.com} (Jeff Putsch)
@code{ar@@nvmr.robin.de} (Andreas Raab)
Jarmo Raiha @code{<jarmo@@ksvltd.FI>}
Scott Reynolds @code{<scott@@clmqt.marquette.Mi.US>}
@code{mcr@@Sandelman.OCUnix.On.Ca} (Michael Richardson)
Kenji Rikitake @code{<kenji@@rcac.astem.or.jp>}
@code{arnold@@cc.gatech.edu} (Arnold Robbins)
@code{steve@@Nyongwa.cam.org} (Steve M. Robbins)
Serge Robyns @code{<sr@@denkart.be>}
Lawrence E. Rosenman @code{<ler@@lerami.lerctr.org>}
Jeff Ross @code{<jeff@@wisdom.bubble.org>}
Aleksey P. Rudnev @code{<alex@@kiae.su>}
"Heiko W.Rupp" @code{<hwr@@pilhuhn.ka.sub.org>}
@code{wolfgang@@wsrcc.com} (Wolfgang S. Rupprecht)
@code{tbr@@tfic.bc.ca} (Tom Rushworth)
@code{jsacco@@ssl.com} (Joseph E. Sacco)
@code{rsalz@@bbn.com} (Rich Salz)
@code{sojurn!mike@@hobbes.cert.sei.cmu.edu} (Mike Sangrey)
Nickolay Saukh @code{<nms@@ussr.EU.net>}
@code{heiko@@lotte.sax.de} (Heiko Schlittermann)
Eric Schnoebelen @code{<eric@@cirr.com>}
@code{russell@@alpha3.ersys.edmonton.ab.ca} (Russell Schulz)
@code{scott@@geom.umn.edu}
Igor V. Semenyuk @code{<iga@@argrd0.argonaut.su>}
Christopher Sawtell @code{<chris@@gerty.equinox.gen.nz>}
@code{schuler@@bds.sub.org} (Bernd Schuler)
@code{uunet!gold.sub.org!root} (Christian Seyb)
@code{s4mjs!mjs@@nirvo.nirvonics.com} (M. J. Shannon Jr.)
@code{peter@@ficc.ferranti.com} (Peter da Silva)
@code{vince@@victrola.sea.wa.us} (Vince Skahan)
@code{frumious!pat} (Patrick Smith)
@code{roscom!monty@@bu.edu} (Monty Solomon)
@code{sommerfeld@@orchard.medford.ma.us} (Bill Sommerfeld)
Julian Stacey @code{<stacey@@guug.de>}
Harlan Stenn @code{<harlan@@mumps.pfcs.com>}
Ralf Stephan @code{<ralf@@ark.abg.sub.org>}
@code{johannes@@titan.westfalen.de} (Johannes Stille)
@code{chs@@antic.apu.fi} (Hannu Strang)
@code{ralf@@reswi.ruhr.de} (Ralf E. Stranzenbach)
@code{sullivan@@Mathcom.com} (S. Sullivan)
Shigeya Suzuki @code{<shigeya@@dink.foretune.co.jp>}
@code{swiers@@plains.NoDak.edu}
Oleg Tabarovsky @code{<olg@@olghome.pccentre.msk.su>}
John Theus @code{<john@@theus.rain.com>}
@code{rd@@aii.com} (Bob Thrush)
ppKarsten Thygesen @code{<karthy@@dannug.dk>}
Graham Toal @code{<gtoal@@pizzabox.demon.co.uk>}
@code{rmtodd@@servalan.servalan.com} (Richard Todd)
Martin Tomes @code{<mt00@@controls.eurotherm.co.uk>}
Len Tower @code{<tower-prep@@ai.mit.edu>}
Mark Towfiq @code{<justice!towfiq@@Eingedi.Newton.MA.US>}
@code{mju@@mudos.ann-arbor.mi.us} (Marc Unangst)
Tomi Vainio @code{<tomppa@@fidata.fi>}
Andrew Vignaux @code{<ajv@@ferrari.datamark.co.nz>}
@code{vogel@@omega.ssw.de} (Andreas Vogel)
@code{jos@@bull.nl} (Jos Vos)
@code{jv@@nl.net} (Johan Vromans)
David Vrona @code{<dave@@sashimi.wwa.com>}
@code{Marcel.Waldvogel@@nice.usergroup.ethz.ch} (Marcel Waldvogel)
@code{steve@@nshore.org} (Stephen J. Walick)
@code{syd@@dsinc.dsi.com} (Syd Weinstein)
@code{gerben@@rna.indiv.nluug.nl} (Gerben Wierda)
@code{jbw@@cs.bu.edu} (Joe Wells)
@code{frnkmth!twwells.com!bill} (T. William Wells)
Peter Wemm @code{<Peter_Wemm@@zeus.dialix.oz.au>}
@code{mauxci!eci386!woods@@apple.com} (Greg A. Woods)
Michael Yu.Yaroslavtsev @code{<mike@@yaranga.ipmce.su>}
Alexei K. Yushin @code{<root@@july.elis.crimea.ua>}
@code{jon@@console.ais.org} (Jon Zeeff)
Matthias Zepf @code{<agnus@@amylnd.stgt.sub.org>}
Eric Ziegast @code{<uunet!ziegast>}
@end example

@node Index (concepts), Index (configuration file), Acknowledgements, Top
@unnumbered Concept Index

@printindex cp

@node Index (configuration file),  , Index (concepts), Top
@unnumbered Configuration File Index

@printindex fn

@contents
@bye