SysIII/usr/src/man/docs/uucp_impl

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Uucp Implementation Description
.AU
D. A. Nowitz
.AI
.MH
.AB
.PP
Uucp is a series of programs designed to permit communication
between
.UX
systems using either dial-up or hardwired communication
lines.
This document gives a detailed implementation
description of the current
implementation of uucp.
Is is designed
for use by an administrator/installer of the system.
It is not meant as a user's guide.
.AE
.CS 12 5 15
.SH
Introduction
.LP
Uucp is a series of programs designed to permit communication between
.UX
systems using either dial-up or
hardwired communication lines.
It can be used for file transfers and remote command execution.
The first version of the system was designed and implemented
by M. E. Lesk.\s-2\u1\d\s+2\ 
.FS
1. M. E. Lesk and A. S. Cohen,
.UX
.I "Software Distribution by Communication Link,"
.ie \n(TN>0 TM-77-1274-3, TM-77-8234-5.
.el private communication.
.FE
This paper describes the current (second) implementation
of the system.
.LP
Uucp is a batch operation.
Files are created in a spool directory for processing
by the uucp demons.
There are three types of files used for the execution
of work.
.I Data\ files
contain data for transfer to remote systems.
.I Work\ files
contain directions for file transfers between systems.
.I Execute\ files
are scripts for
.UX
commands that
involve the resources of one or more systems.
.LP
There are four primary programs:
.RS
.IP uucp 10
builds
.I "work files"
and gathers
.I "data files"
in the spool directory
for data transmission.
.IP uux
creates
.I "work files" ,
.I "execute files" ,
and gathers
.I "data files"
for the remote execution of
.UX
commands.
.IP uucico
executes the work files for data transmission.
.IP uuxqt
executes the scripts for
.UX
command execution.
.RE
.LP
There are a couple of administrative programs:
.RS
.IP uulog 10
gathers temporary log files that may occur due to lockout of
the uucp log file
and reports some information such as copy requests and completion status.
.IP uuclean
removes old files from the spool directory.
.LP
.RE
The remainder of this paper will describe the operation
of each program, the installation of the system,
the security aspects of the system,
the files required for execution,
and the administration of the system.
.NH
Uucp\-UNIX to UNIX File Copy
.LP
The
.I uucp
command is the user's primary interface with the system.
The command is designed to look like
.I cp
to the user.
The syntax is
.IP
.I uucp\ \ 
.B [
option
.B ]
\ .\|.\|.\ \ \ source\ .\|.\|.\ \ \ destination
.LP
where the source and destination
may contain the prefix
.I system-name\^!\| ,
which indicates the system where the file
or files reside
or where they will be copied.
.LP
.I Uucp
has several options:
.RS
.IP \-d 10
Make directories when necessary for copying the file.
.IP \-c
Don't copy source files to the spool directory,
but use the specified source when the actual
transfer takes place.
.IP \-e\fIsys\fR
Send this job to system
.I sys
to execute.
(Note that this will only work when the system
.I sys
allows
.I uuxqt
to execute a
.I uucp
command.
See the ``Uuxqt'' and ``Security'' sections.)
.IP \-g\fIletter\fR
Put
.I letter
in as the grade in the name of the work file.
(This can be used to change the order of work for a particular
machine.)
.IP \-m
Send mail to the requester on completion of the work.
.IP \-n\fIuser\fR
Notify
.I user
on the remote machine that a file has been sent.
.LP
There are several options available for debugging:
.IP \-r 10
Queue the job but do not start
.I uucico
program.
.IP \-x\fInum\fR
.I Num
is a level number between 1 and 9;
higher numbers give more debugging output.
.RE
.LP
The destination may be a directory name,
in which case the file name is taken from the last part of the
source's name.
If the directory exists, it must be writable by everybody.
(Note that if the destination is a directory name and the ``\-d'' option
is specified to create the directory, the directory name must be followed
by ``/''.)
The source
name may contain special shell characters
such as ``?*[]''.
These will be expanded on the appropriate system.
.LP
The command
.IP "" 12
uucp\ \ \ *\s+4.\s-4c\ \ \ usg\^!\^/usr/dan
.LP
will set up the transfer of all files whose names end with ``\s+4.\s-4c''
to the ``/usr/dan'' directory on the``usg'' machine.
.LP
The source and/or destination names may also contain a
.I ~user
prefix.
This translates to the login directory of
.I user
on the specified system.
File names beginning with ``~/'' translate into the public directory
(usually /usr/spool/uucppublic)
on the remote system.
For names with partial path-names,
the current directory is prepended to the file name.
File names with
\&\s+4..\s-4/
are not permitted
for security reasons.
.LP
The command
.IP "" 12
uucp\ \ \ usg\^!\^~dan/*\s+4.\s-4h\ \ \ ~dan
.LP
will set up the transfer of files whose names end with ``\s+4.\s-4h''
in dan's login
directory on system ``usg'' to dan's local
login directory.
.LP
For each source file,
the program will check the source and destination
file-names,
the system-part of each argument,
and the options
to classify the work into several types:
.RS
.IP [1]
Copy source to destination on local system.
.IP [2]
Receive files from other systems.
.IP [3]
Send files to a remote system.
.IP [4]
Send files from remote systems
to another remote system.
.IP [5]
Receive files from remote systems when the source
contains special shell characters as
mentioned above.
.IP [6]
Request that the
.I uucp
command be executed by a remote system.
.RE
.LP
After the work has been set up in the spool directory,
the
.I uucico
program is started to try to contact the other
machine and execute the work (unless the \-r option
was specified).
.SH
Type 1 - local copy
.LP
The copy is done locally.
The
.I \-m
and
.I \-n
options are not honored in this case.
.SH
Type 2 - receive files
.LP
A
.I "work file"
is created or appended with a one line entry for each request.
The upper limit to the number of files per
.I "work file"
is set in
.I uucp.h.
(The default setting is 20.)
After the limit has been reached, a new
.I "work file"
is created.
(All
.I "work files"
and
.I "execute files"
use a blank as the field separator.)
The fields for these entries are given below.
.RS
.IP [1]
R
.IP [2]
The full path-name of the source or a ~something/path-name.
The
.I ~something
part will be expanded on the remote system.
.IP [3]
The full path-name of the destination file.
If the
.I ~something
notation is used, it will be immediately
expanded.
.IP [4]
The user's login name.
.IP [5]
A ``\-'' followed by an option list.
The options \-m and \-d may appear.
.RE
.KS
.SH
Type 3 - send files
.LP
Each source file
is copied into a
.I "data file"
in the spool directory.
(A ``\-c'' option on the
.I uucp
command will prevent the
.I "data file"
from being made.
In this case, the file will be transmitted from
the indicated source.)
The fields for these entries are given below.
.RS
.IP [1]
S
.IP [2]
The full-path name of the source file.
.IP [3]
The full-path name of the destination or
~something/file-name.
.IP [4]
The user's login name.
.IP [5]
A ``\-'' followed by an option list.
The options \-d, \-m, and \-n may appear.
.IP [6]
The name of the
.I "data file"
in the spool directory.
A dummy name, ``D.0'' is used when the \-c option is specified.
.IP [7]
The file mode bits of the source file
in octal print format
(e.g., 0666).
.IP [8]
The user on the remote system to be notified upon completion of the
file copy when the ``\-n'' option is specified.
.RE
.KE
.SH
Type 4 and Type 5 - remote uucp required 
.LP
.I Uucp
generates a
.I uucp
command and sends it to the remote machine;
the remote
.I uucico
executes the
.I uucp
command.
.SH
Type 6 - remote execution
.LP
This occurs when the ``\-e'' option is used.
In this case, the
.I uux
facility is used to create and send the request.
This requires that the remote
.I uuxqt
program allows the
.I uucp
command.
.NH
Uux\-UNIX To UNIX Execution
.LP
The
.I uux
command is used to set up the execution of a
.UX
command
where the execution machine and/or some of the
files are remote.
The syntax of the uux command is
.IP
.I uux\ \ 
.B [
\-
.B "] ["
option
.B ]
\ .\|.\|.\ \ command-string
.LP
where the command-string is made up of one or more arguments.
All special shell characters such as ``<>\(bv^'' must be quoted
either by quoting the entire command-string
or quoting the character as a separate argument.
Within the command-string, the command and file names may
contain a
.I system-name\^!\|
prefix.
All arguments that do not contain a ``!'' will not
be treated as files.
(They will not be copied to the execution machine.)
An argument that contains a ``!'' but is not to be treated as a file
at the present time,
can be escaped by using ``()'' around
the argument.
(Note that the ``()'' symbols must usually be escaped with a ``\\'' symbol.)
The ``\-'' is used to indicate that the standard input
for
.I command-string
should be inherited from the standard input
of the
.I uux
command.
The following options are available for debugging:
.RS
.IP \-r 10
Don't start
.I uucico
or
.I uuxqt
after queuing the job.
.IP \-x\fInum\fR
.I Num
is a level number between 1 and 9;
higher numbers give more debugging output.
.RE
.LP
The command
.IP "" 12
pr\ \ abc\ \ \(bv\ \ uux\ \ \-\ \ usg\^!\^lpr
.LP
will set up the output of ``pr abc''
as standard input to an lpr command
to be executed on system ``usg''.
.LP
.I Uux
generates an
.I "execute file"
that contains the
names of the files required
for execution (including standard input),
the user's login name, the destination
of the standard output, and the command to be executed.
This file is either put in the spool directory
for local execution or sent to the remote system using
a send command (type 3 above).
.LP
For required files that are not on the execution machine,
.I uux
will generate receive command files (type 2 above).
These command-files will be put on the execution machine
for execution by the
.I uucico
program.
.LP
The
.I "execute file"
contains a script that
will be processed
by the
.I uuxqt
program.
It is made up of several lines,
each of which contains an identification character
and one or more arguments.
The lines are described below.
.RS
.SH
User Line
.IP
U\ \ user\ \ system
.LP
where the
.I user
and
.I system
are the requester's login name and system.
.SH
Required File Line
.IP
F\ \ file-name\ \ real-name
.LP
where the
.I file-name
is a unique name used for file transmission
and
.I real-name
is the last part of the actual file name (contains no
path information).
Zero or more of these lines may be present.
The
.I uuxqt
program will check for the existence of all these
files before the command is executed.
.SH
Standard Input Line
.IP
I\ \ file-name
.LP
The standard input is either specified by a ``<'' in the
command-string or inherited from the standard input of the
.I uux
command if the ``\-'' option is used.
If a standard input is not specified,
``/dev/null'' is used.
(Note that if there is a standard input specified, it will also
appear in an ``F'' line.)
.SH
Standard Output Line
.IP
O\ \ file-name\ \ system-name
.LP
The standard output is specified by a ``>'' within the
command-string.
If a standard output is not specified,
``/dev/null'' is used.
(Note that the use of ``>>'' is not implemented.)
.SH
Command Line
.IP
C\ \ command\ \ 
.B [
arguments
.B ]
\ .\|.\|.
.LP
The arguments are those specified in the command-string.
The standard input and standard output will not appear on this
line.
All
.I "required files"
will be moved to the execution directory
(usually /usr/lib/uucp/.XQTDIR)
and the
.UX
command is executed using the shell specified in the
.I uucp\s+4.\s-4h
header file.
In addition, a shell ``PATH'' statement is prepended
to the command line as specified in the
.I uuxqt
program.
(Note that a check is made to see that the command
is allowed as specified in the
.I uuxqt
program.)
After execution, the standard output is copied or sent to the proper place.
.RE
.NH
Uucico\-Copy In, Copy Out
.LP
The
.I uucico
program will perform several major functions:
.RS
.IP \- 3
Scan the spool directory for work.
.IP \-
Place a call to a remote system.
.IP \-
Negotiate a line protocol to be used.
.IP \-
Execute all requests from both systems.
.IP \-
Log work requests and work completions.
.RE
.LP
.I Uucico
may be started in several ways:
.RS
.IP a) 5
by a system demon specified in a crontab entry,
.IP b)
by one of the
.I
uucp, uux, uuxqt
.R
or
.I uucico
programs,
.IP c)
directly by the user (this is usually for testing),
.IP d)
by a remote system.
(The uucico program should be specified as the ``shell''
field in the ``/etc/passwd'' file for the 
logins used by remote systems to access uucp.)
.RE
.LP
When started by method a, b or c, the program is considered to
be in
.I MASTER
mode.
In this mode, a connection will be made to a remote system.
If started by a remote system (method d),
the program is considered to be in
.I SLAVE
mode.
.LP
The
.I MASTER
mode will operate in one of two ways.
If no system name is specified
(\-s option not specified)
the program will scan the spool directory for
systems to call.
If a system name is specified, that system will be called,
and work will only be done for that system.
.LP
.I Uucico
is generally started by another program.
There are several options used for execution:
.RS
.IP \-r1 10
Start the program in
.I MASTER
mode.
This is used when
.I uucico
is started by a program or ``cron'' shell.
.IP \-s\fIsys\fR
Do work only for system
.I sys.
If
.I \-s
is specified,
a call to the specified system
will be made even if there is no work for system
.I sys
in the spool directory.
This is useful for polling systems that do not have
the hardware to initiate a connection.
.LP
The following options are used primarily for debugging:
.IP \-d\fIdir\fR
Use directory
.I dir
for the spool directory.
.IP \-x\fInum\fR
.I Num
is a level number between 1 and 9;
higher numbers give more debugging output.
.RE
.LP
The next part of this section will describe the major steps within
the
.I uucico
program.
.SH
Scan For Work
.LP
The names of the work related files in the spool directory have format
.IP
type \s+4.\s-4 system-name grade number
.LP
where
.IP
.I type
is an upper case letter
(
.I C
\-\ copy command file,
.I D
\-\ data file,
.I X
\-\ execute file),
.IP
.I system-name
is the remote system,
.IP
.I grade
is a character,
.IP
.I number
is a four digit, zero padded sequence number.
.LP
The file
.IP "" 12
C\s+4.\s-4res45n0031
.LP
would be a
.I "work file"
for a file transfer between the local
machine and the ``res45'' machine.
.LP
The scan for work is done by looking through the
spool directory for
.I "work files"
(files with prefix ``C\s+4.\s-4'').
A list is made of all systems to be called.
.I Uucico
will then call each system and process all
.I "work files" .
.SH
Call Remote System
.LP
The call is made using information from several
files that reside in the uucp program directory
(usually /usr/lib/uucp).
At the start of the call process, a lock is
set to forbid multiple conversations 
between the same two systems.
.LP
The
.I L\^\s+4.\s-4sys
file contains information required to make the remote connection:
.RS
.IP [1]
system name,
.IP [2]
times to call the system
(days-of-week and times-of-day)
and the minimum time delay before retry,
.IP [3]
device or device type to be used for call,
.IP [4]
line class (this is the line speed on almost all systems),
.IP [5]
phone number if field [3] is
.I ACU
or the device
if not
.I ACU ,
.IP [6]
login information (zero or more fields),
.RE
.LP
The time field is checked against the present time to see
if the call should be made.
The
.I "phone number"
may contain abbreviations (e.g., mh, py, boston) that get translated into dial
sequences using the
.I L-dialcodes
file.
.LP
The
.I L-devices
file is scanned using fields [3] and [4] from the
.I L\^\s+4.\s-4sys
file to find an available device for the call.
The program will try each devices that satisfy
[3] and [4] until a call is made, or no more
devices can be tried.
If a device is successfully opened, a lock file
is created.
If the call is completed, the
.I
login information
.R
(field [6] of
.I L\^\s+4.\s-4sys )
is used to login.
.LP
The conversation between the two
.I uucico
programs begins with a handshake started by the called,
.I SLAVE ,
system.
The
.I SLAVE
sends a message to let the
.I MASTER
know it is ready to receive the system
identification and conversation sequence number.
The response from the
.I MASTER
is
verified by the
.I SLAVE
and if acceptable, protocol selection begins.
The
.I SLAVE
can also reply with a ``call-back required''
message in which case, the current conversation
is terminated.
.SH
Line Protocol Selection
.LP
The remote system sends a message
.IP "" 12
P\fIproto-list\fR
.LP
where
.I proto-list
is a string of characters, each
representing a line protocol.
.LP
The calling program checks
.I proto-list
for a letter corresponding to an available line
protocol and returns a
.I use-protocol
message.
The
.I use-protocol
message is
.IP "" 12
U\fIcode\fR
.LP
where
.I code
is either a one character
protocol letter or
``N'',
which means there is no common protocol.
.SH
Work Processing
.LP
The
.I MASTER
program does a work search similar to the
one used in the ``Scan For Work'' section.
(The 
.I MASTER
has been specified by the ``\-r1'' uucico option.)
Each message used during the
work processing is specified by the first
character of the message:
.RS
.IP S 3
send a file,
.IP R
receive a file,
.IP C
copy complete,
.IP X
execute a
.I uucp
command,
.IP H
hangup.
.RE
.LP
The
.I MASTER
will send
.I R ,
.I S
or
.I X
messages until all work for the remote system is complete,
at which point an
.I H
message will be sent.
The
.I SLAVE
will reply with
.I SY ,
.I SN ,
.I RY ,
.I RN ,
.I HY ,
.I HN ,
.I XY ,
or
.I XN ,
corresponding to
.I yes
or
.I no
for each request.
.LP
The send and receive replies are
based on permission to access the
requested file/directory using the
.I USERFILE
and read/write permissions of the file/directory.
After each file is copied into the spool directory
of the receiving system,
a copy-complete message is sent by the receiver of the file.
The message
.I CY
will be sent if the
file has successfully been moved from the
spool directory to the destination.
Otherwise, a
.I CN
message is sent.
(In this case,
the file is put in the public directory, usually /usr/spool/uucppublic,
and the requester is notified by mail.)
The requests and results are logged on both systems.
.LP
The hangup response is determined by a
work scan of the
.I SLAVE 's
spool directory.
If work for the remote system exists
an
.I HN
message is sent and the programs switch roles.
If no work exists, an
.I HY
response is sent.
.SH
Conversation Termination
.LP
When a
.I HY
message is received by the
.I MASTER
it is echoed back to the
.I SLAVE
and the protocols are turned off.
Each program sends a final ``OO'' message to the
other.
The original
.I SLAVE
program will clean up and terminate.
The
.I MASTER
will proceed to call other systems
unless a ``\-s'' option was specified.
.LP
.NH
Uuxqt\-Uucp Command Execution
.LP
The
.I uuxqt
program is used to execute
scripts
generated by
.I uux.
The
.I uuxqt
program may be started by either the
.I uucico
or
.I uux
programs or a demon specified by a
.I crontab
entry.
The program scans the spool directory for
.I
execute files
.R
(prefix ``X\s+4.\s-4'').
Each one is checked to see if all the required files are available and
if so, the command line is verified and executed.
.LP
The
.I
execute file
.R
is described in the ``Uux''
section above.
.LP
The execution is accomplished by executing a
``sh \-c''
of the command line after appropriate
standard input and standard output have been opened.
If a standard output is specified, the program
will create a send command or copy the output
file as appropriate.
.NH
Uulog\-Uucp Log Inquiry
.LP
When a
.I uucp
program can not make a log entry directly into the
.I LOGFILE
an individual log file is created:
a file with prefix
.I LOG .
This will sometimes occur when more than one uucp process is running.
Periodically,
.I uulog
may be executed to append these files to the
.I LOGFILE .
.LP
The
.I uulog
program may also be used to request the output of
.I LOGFILE
entries.
The request is specified by the use of the
options:
.RS
.IP \-s\fIsys\fR 9
Print entries where
.I sys
is the remote system name,
.IP \-u\fIuser\fR
Print entries for user
.I user.
.RE
.LP
The intersection of lines satisfying the two options is output.
A null
.I sys
or
.I user
means all system names or users respectively.
.NH
Uuclean\-Uucp Spool Directory Cleanup
.LP
This program is typically started by the uucp daily demon.
Its function is to remove files from the spool directory that
are more than 3 days old.
These are usually files for work that can not be completed.
The requester of this work is notified that the files have been deleted.
.LP
There are several options:
.RS
.IP \-d\fIdir\fR 10
The directory to be scanned is
.I dir .
.IP \-m
Send mail to the owner of each file being removed.
(Note that most files put into the spool directory
will be owned by the owner of the
uucp programs since the setuid bit will be set on these
programs.
This mail is sometimes useful for administration.)
.IP \-n\fIhours\fR
Change the aging time from 72 hours to
.I hours
hours.
.IP \-p\fIpre\fR
Examine files with prefix
.I pre
for deletion.
(Up to 10 of these options may be specified.)
.IP \-x\fInum\fR
This is the level of debugging output desired.
.RE
.NH
Security
.LP
.in +\w'\ \(rh\ \ 'u
.ti -\w'\ \(rh\ \ 'u
.I
\ \(rh\ \ The uucp system, left unrestricted,
will let any outside user execute any commands
and copy out/in any file that is readable/writable
by a uucp login user.
It is up to the individual sites to be aware of this and
apply the protections that they feel are necessary.
.R
.in -\w'\ \(rh\ \ 'u
.LP
There are several security features available aside from the
normal file mode protections.
These must be set up by the administrator of the
.I uucp
system.
.IP \- 3
The login for uucp does not get a standard shell.
Instead, the
.I uucico
program is started
so that all work is done through
.I uucico .
.IP \-
The owner of the uucp programs should be an administrative login.
It should not be one of the logins used for remote system access to
uucp.
.IP \-
A path check is done on file names that are to be sent
or received.
The
.I USERFILE
supplies the information for these checks.
The
.I USERFILE
can also be set up to require call-back
for certain login-ids.
(See the ``Files Required For Execution'' section
for the file description.)
.IP \-
A conversation sequence count can be set up so
that the called system
can be more confident of the caller's identity.
.IP \-
The
.I uuxqt
program comes with a list of commands that it
will execute.
A ``PATH'' shell statement is prepended to the command
line as specified in the
.I uuxqt
program.
The installer may modify the list or remove the
restrictions as desired.
.IP \-
The
.I L\^\s+4.\s-4sys
file should be owned by the uucp administrative login and have mode 0400
to protect the phone numbers and login information
for remote sites.
.IP \-
The programs
.I uucp ,
.I uucico ,
.I uux ,
.I uuxqt ,
.I uulog ,
and
.I uuclean
should be
owned by the uucp administrative login, have the setuid bit set,
and have only execute permissions.
.NH
Uucp Installation
.LP
It is assumed that the
.I "login name"
used by a remote computer to call into a local computer
is not the same as the login name of a normal user
or the uucp administrative login.
However, several remote computers may use the same
login name.
.LP
Each computer should be given a unique
.I "system name"
that is transmitted at the start of each call.
This name identifies the calling machine to the called machine.
The
.I login/system
names are used for security as described later in the
.I USERFILE
section.
.LP
There are several source modifications that may be required
before the system programs are compiled.
These relate to the directories, local system name,
and attributes of the local environment.
.LP
There are several directories used by the uucp system:
.RS
.IP lib 12
(/usr/src/cmd/uucp) \-
This directory contains the uucp system source files.
.IP program
(/usr/lib/uucp) \-
This is the directory used for some of the executable system programs and
the system files.
Some of the programs reside in ``/usr/bin''.
.IP spool
(/usr/spool/uucp) \-
This is the uucp system spool directory.
.IP xqtdir
(/usr/lib/uucp/.XQTDIR) \-
This directory is used during execution of
the
.I uux
scripts.
.RE
.LP
The names in parentheses above are the default values
for the directories.
The italicized names
.I
lib, program, xqtdir,
.R
and
.I spool
will be used in the following text to represent the
appropriate directory names.
.LP
There are two files that may require modification,
the
.I makefile
file and the
.I uucp\s+4.\s-4h
file.
(On some systems, the makefile is named
.I uucp.mk .)
In addition, the ``uuxqt.c'' program may be modified as indicated in
the ``Security'' section above.
The following paragraphs describe the modifications.
.SH
uucp\s+4.\s-4h modification
.LP
Several manifests in ``uucp.h'' may need modification for the local
system environment:
.RS
.IP UNAME 12
should be defined if the ``uname'' function is available.
.IP MYNAME
should be modified to the name of the local system if
UNAME is
.I not defined.
.IP ACULAST
is the character required by the ACU as the last character.
For most systems, it is a ``\-''.
.IP DATAKIT
should be defined if the system is on a datakit network.
.IP DIALOUT
should be defined if the ``C'' library routine ``dialout''
is available.
.RE
.SH
makefile modification
.LP
There are several
.I make
variable definitions that may need modification:
.RS
.IP INSDIR 10
is the
.I program
directory
(e.g., INSDIR=/usr/lib/uucp).
This parameter is used if ``make cp'' or
``make install'' is used.
.IP IOCTL
is required to be set if the ``ioctl'' routine is
.I not
available in the standard
``C'' library;
the statement
``IOCTL=ioctl\s+4.\s-4o'' is required in this case.
.IP PUBDIR
is a public directory for remote access.
This is also the login directory for remote uucp users.
It should be the same as that defined in ``uucp.h''.
.IP SPOOL
is the uucp spool directory.
This should be the same as that defined in ``uucp.h''.
.IP XQTDIR
is the directory for uuxqt to use for command execution.
It is also defined in ``uucp.h''.
.IP OWNER
is the administrative login for uucp.
.RE
.SH
Compile the system
.LP
The command
.IP "" 12
make install
.LP
will make the required directories,
compile all programs,
set the proper file modes,
and copy the programs to the proper directories.
This command should be run as
.I root .
The command
.IP "" 12
make
.LP
will compile the entire system.
.LP
The programs
.I uucp ,
.I uux ,
and
.I uulog
should be put in ``/usr/bin''.
The programs
.I uuxqt ,
.I uucico ,
and
.I uuclean
should be put in the
.I program
directory.
.SH
Files Required For Execution
.LP
There are four files that are required for execution.
They should reside in the
.I program
directory.
The field separator for all files is a space.
.SH
L-devices
.LP
This file contains call-unit device and hardwired connection information.
The special device files are assumed to be in the
.I /dev
directory.
The format for each entry is
.IP "" 12
type\ \ line\ \ call-unit\ \ speed
.LP
where
.RS
.IP type 12
is a device type such as ACU or DIR.
The field can also be used to specify particular ACUs for some
calls by using a suffix on the ACU field, e.g., ACU3.
This names should be used in
.I L\^\s+4.\s-4sys .
.IP line
is the device for the line (e.g., cul0).
.IP call-unit
is the automatic call unit associated with
.I line
(e.g., cua0).
Hardwired lines have a number ``0'' in this field.
.IP speed
is the line speed.
.RE
.LP
The line
.IP "" 12
ACU\ \ cul0\ \ cua0\ \ 300
.LP
would be set up for a system that
has device ``/dev/cul0'' wired to a call-unit ``/dev/cua0''
for use at 300 baud.
.SH
L-dialcodes
.LP
This file contains the dialcode abbreviations used
in the
.I L\^\s+4.\s-4sys
file (e.g., py, mh, boston).
The entry format is
.IP "" 12
abb\ \ dial-seq
.LP
where
.RS
.IP abb 12
is the abbreviation,
.IP dial-seq
is the dial sequence to call that location.
.RE
.LP
The line
.IP "" 12
py\ \ 165\-
.LP
would be set up so that entry py7777 would
send 165\-7777 to the dial-unit.
.SH
USERFILE
.LP
This file contains user accessibility information.
It specifies four types of constraint:
.RS
.IP [1]
which files can be accessed by a normal user of the local machine,
.IP [2]
which files can be accessed from a remote computer,
.IP [3]
which login name is used by a particular remote computer,
.IP [4]
whether a remote computer should be called back in order to confirm
its identity.
.RE
.LP
Each line in the file has the format
.IP "" 6
login,sys\ \ 
.B [
c
.B ]
\ \ path-name\ \ 
.B [
path-name
.B ]
\ .\|.\|.
.LP
where
.RS
.IP login 12
is the login name for a user or the remote computer,
.IP  sys
is the system name for a remote computer,
.IP c
is the optional
.I
call-back required
.R
flag,
.IP path-name
is a path-name prefix that is acceptable for
.I sys .
.LP
.RE
.LP
The constraints are implemented as follows.
.RS
.IP [1]
When the program is obeying a command stored on the local machine,
.I MASTER
mode,
the path-names allowed are those given on the first line in the
.I USERFILE
that has the login name of the user
who entered the command.
If no such line is found, the first line with a
.I null
login name is used.
.IP [2]
When the program is responding to a command from a remote machine,
.I SLAVE
mode, the path-names allowed are those given on the first line
in the file that has the system name that matches
the remote machine.
If no such line is found, the first one with a
.I null
system name is used.
.IP [3]
When a remote computer logs in, the login name that
it uses
.I must
appear in the
.I USERFILE .
There may be several lines with the same login name but one of them must
either have the name of the remote system or must contain a
.I null
system name.
.IP [4]
If the line matched in ([3]) contains a ``c'',
the remote machine is called back before any transactions take place.
.RE
.LP
The line
.IP "" 12
u,m  /usr/xyz
.LP
allows machine
.I m
to login with name
.I u
and request the transfer of files whose names start with
``/usr/xyz''.
.LP
The line
.IP "" 12
dan,  /usr/dan
.LP
allows the ordinary user
.I dan
to issue commands for files whose name starts with
``/usr/dan''.
(Note that this type restriction is seldom used.)
.LP
The lines
.IP "" 12
u,m /usr/xyz  /usr/spool
.br
u,  /usr/spool
.LP
allows any remote machine to login with name
.I u .
If its system name is not
.I m ,
it can only ask to transfer files whose names start with
``/usr/spool''.
If it is system
.I m ,
it can send files from paths ``/usr/xyz'' as well as ``/usr/spool''.
.LP
The lines
.IP "" 12
root,  /
.br
,   /usr
.LP
allow any user to transfer files beginning with ``/usr''
but the user with login
.I root
can transfer any file.
(Note that any file that is to be transferred must be readable by anybody.)
.SH
L\s+4.\s-4sys
.LP
Each entry in this file represents one system
that can be called by the local uucp programs.
More than one line may be present for a particular system.
In this case, the additional lines represent alternative
communication paths that will be tried in sequential order.
The fields are described below.
.RS
.SH
system name
.LP
The name of the remote system.
.SH
time
.LP
This is a string that indicates the days-of-week
and times-of-day when the system should
be called
(e.g., MoTuTh0800\-1730).
.LP
The day portion may be a list containing
some of
.IP
.I
Su Mo Tu We Th Fr Sa
.R
.LP
or it may be
.I Wk
for any week-day or
.I Any
for any day.
.LP
The time should be a range of times (e.g., 0800\-1230).
If no time portion is specified, any time
of day is assumed to be okay for the call.
Note that a time range that spans 0000 is permitted, for example,
0800-0600 means all times are ok other than times between 6 and 8 am.
.LP
An optional subfield is available to indicate the minimum time (minutes)
before a retry following a failed attempt.
The subfield separator is a ``,''.
(e.g., Any,9 means call any time but wait at least 9 minutes after a failure
has occurred.)
.SH
device
.LP
This is either
.I ACU
or the hardwired device to be used for the call.
For the hardwired case, the last part of the
special file name is used (e.g., tty0).
.SH
class
.LP
This is usually the line speed for the call (e.g., 300).
The exception is when the ``C'' library routine ``dialout'' is
available in which case this is the dialout class.
.SH
phone
.LP
The phone number is made up of an optional
alphabetic abbreviation and a numeric part.
The abbreviation should be one that appears in the
.I L-dialcodes
file (e.g., mh5900, boston995\-9980).
For the hardwired devices, this field contains
the same string as used for the
.I device
field.
.SH
login
.LP
The login information is given as a series of
fields and subfields in the format
.IP
.B [
expect\ \ send
.B ]
\ .\|.\|.
.LP
where
.I expect
is the string expected to be read and
.I send
is the string to be sent when the
.I expect
string is received.
.LP
The expect field may be made up of subfields
of the form
.IP
expect\fB[\fR\-send\-expect\fB]\fR .\|.\|.
.LP
where the
.I send
is sent if the prior
.I expect
is
.I not
successfully read
and the
.I expect
following the
.I send
is the next expected string.
(e.g., login--login will expect 
.I login ;
if it gets it, the program will go on to the next field;
if it does not get
.I login ,
it will send
.I null
followed by a new line,
then expect
.I login
again.)
.LP
There are two special names available to be sent
during the login sequence.
The string
.I EOT
will send an EOT character and the string
.I BREAK
will try to send a BREAK character.
(The
.I BREAK
character is simulated using line speed changes
and null characters and may not work on all
devices and/or systems.)
A number from 1 to 9 may follow the
.I BREAK
for example,
.I BREAK1
will send 1 null character instead of the default of
3.
Note that
.I BREAK1
usually works best for 300/1200 baud lines.
.RE
.LP
A typical entry in the L\s+4.\s-4sys file would be
.IP "" 6
sys\ \ Any\ \ ACU\ \ 300\ \ mh7654\ \ login\ \ uucp\ \ ssword:\ \ word
.LP
The expect algorithm match all or part of the input
string as illustrated in the password field above.
.RE
.NH
Administration
.LP
This section indicates some events and files that must be
administered for the
uucp system.
Some administration can be accomplished by 
.I "shell files"
initiated by
.I crontab
entries.
Others will require manual intervention.
Some sample 
.I "shell files"
are given toward the end of this section.
.SH
SQFILE \- sequence check file
.LP
This file is set up in the
.I program
directory and contains an entry for each remote
system with which you agree to perform conversation
sequence checks.
The initial entry is just the system name of
the remote system.
The first conversation will add
the conversation count and the date/time of the most
resent conversation.
These items will be updated with each conversation.
If a sequence check fails, the entry will have to
be adjusted manually.
.SH
TM \- temporary data files
.LP
These files are created in the
.I spool
directory while a file is being copied
from a remote machine.
Their names have the form
.IP "" 12
\fBTM.\^\fRpid\s+4.\s-4ddd
.LP
where
.I pid
is a process-id and
.I ddd
is a sequential three digit number starting at zero.
After the entire file is received, the
.I TM
file is moved/copied to the requested destination.
If processing is abnormally terminated
the file will remain in the
spool directory.
The leftover files should be periodically removed;
the
.I uuclean
program is useful in this regard.
The command
.IP "" 12
.I program /uuclean\ \ \-pTM
.LP
will remove all
.I TM
files older than three days.
.SH
LOG \- log entry files
.LP
During execution, log information is appended to the
.I LOGFILE .
If this file is locked by another process, the log
information is placed in individual log files which will have prefix
.I LOG .
These files should be combined into the
.I LOGFILE
by using the
.I uulog
program.
This program will append the
.I LOGFILE
with the individual log files.
The command
.IP "" 12
uulog
.LP
will accomplish the merge.
Options are available to print some or all the
log entries after the files are merged.
The
.I LOGFILE
should be removed periodically.
.LP
The
.I LOG .
files are created initially with mode 0222.
If the program that creates the file terminates normally,
it changes the
mode to 0666.
Aborted runs may leave the files with mode
0222 and the
.I uulog
program will not read or remove them.
To remove them, either use
.I rm ,
.I uuclean ,
or change the mode to 0666 and let
.I uulog
merge them into the
.I LOGFILE .
.SH
STST \- system status files
.LP
These files are created in the spool directory by the
.I uucico
program.
They contain information such as login, dialup or
sequence check failures or will contain a
.I TALKING
status when two machines are conversing.
The form of the file name is
.IP
\fBSTST.\^\fRsys
.LP
where
.I sys
is the remote system name.
.LP
For ordinary failures, such as dialup or login, the file will
prevent repeated tries for about 55 minutes.
This is the default time;
it can be changed on an individual system basis by a subfield of the time
field in the
.I L\^\s+4.\s-4sys
file.
For sequence check failures, the file must be removed before
any future attempts to converse with that remote system.
.SH
LCK \- lock files
.LP
Lock files are created for each device in use (e.g., automatic calling
unit) and each system conversing.
This prevents duplicate conversations and multiple attempts to use the
same device.
The form of the lock file name is
.IP "" 12
\fBLCK..\^\fRstr
.LP
where
.I str
is either a device or system name.
The files may be left in the spool directory if runs abort
(usually only on system crashes).
They will be ignored (reused) after 1.5 hours.
When runs abort and calls are desired before the time limit,
the lock files should be removed.
.SH
ERRLOG \- uucp system error file
.LP
This file is created in the
.I spool
directory to record uucp system errors.
Entries in this file should be rare.
The messages come from the
.I ASSERT
statements in the
various programs.
Wrong modes on files or directories,
missing files,
and read/write system call failures on the
transmission channel may cause entries in
the 
.I ERRLOG
file.
.SH
Shell Files
.LP
The
.I uucp
program will spool work and attempt to start the
.I uucico
program, but
.I uucico
will not always be able to execute the request immediately.
Therefore, the
.I uucico
program should be periodically started.
The command to start
.I uucico
can be put in a ``shell'' file with a command to merge
.I LOG .
files and started by a crontab entry on an hourly basis.
The file could contain the commands
.IP
/usr/bin/uulog
.br
.I program /uucico
\ \ \-r1\ \ \-sinter
.br
.I program /uucico
\ \ \-r1
.LP
The ``\-r1'' option is required to start the
.I uucico
program in
.I MASTER
mode.
The ``\-s'' option can be used for polling as illustrated in the
second line where machine
.I inter
is being polled.
The third line will process all other spooled work.
.LP
Another shell file may be set up on a daily basis to remove
.I TM ,
.I ST
and
.I LCK
files
and
.I C.
or
.I D.
files for work that can not be accomplished for
reasons like bad phone number, login changes etc.
A shell file containing commands like
.IP
.I program /uuclean
\ \ \-pTM \-pC\s+4.\s-4 \-pD\s+4.\s-4
.br
.I program /uuclean
\ \ \-pST \-pLCK \-n12
.LP
can be used.
Note that the ``\-n12'' option causes the
.I ST
and
.I LCK
files older than 12 hours to be deleted.
The absence of the ``\-n'' option will use a three day time
limit.
.LP
A daily or weekly shell should also be created
to remove or save old
.I LOGFILE s.
A shell like
.IP
cp
.I spool /LOGFILE
\ \ 
.I spool /o\s+4.\s-4LOGFILE
.br
rm
.I spool /LOGFILE
.LP
can be used.
.SH
Login Entry
.LP
Two or more logins should be set up for
.I uucp .
One should be an administrative login:
the owner of all the uucp programs, directories and files.
All others are used by remote systems to access the uucp system.
Each of the ``/etc/passwd'' entries for the
.I access
logins should have
``\fIprogram\fR/uucico''
as the shell to be executed.
The login directory should be the public directory (usually
/usr/spool/uucppublic).
The various
.I access
login names are used in the
.I USERFILE
to restrict file access.
.SH
File Modes
.LP
The programs
.I uucp ,
.I uux ,
.I uucico ,
.I uulog ,
.I uuclean
and
.I uuxqt
should be owned by the
.I uucp
administrative login with the ``setuid'' bit set and only execute
permissions (e.g., mode 04111).
The
.I L\^\s+4.\s-4sys ,
.I SQFILE
and the
.I USERFILE ,
which are put in the
.I program
directory should be owned by
the
.I uucp
administrative login and set with mode 0400.
The mode of
.I spool
should be ``0755''.
The mode of
.I xqtdir
should be ``0777''.
The
.I L-dialcodes
and the
.I L-devices
files should have mode 0444.
.sp
.I "January 1980"