gup - A Group Update Program that accepts commands by mail to edit a
newsgroup subscription file for subsequent use by news systems such as
INN and C-News.
gup [-hvP] -a active_path [-d home_directory] [-l log_path]
[-m reply_headers] [-n newsgroups_path]
[-s sites_directory] [-M Mail_command]
The sole purpose of gup is to automate the tedious process of editing
group selection patterns defined in the news configuration files (eg:
‘‘newsfeeds’’ for INN and ‘‘sys’’ for C-News).
Gup is of use to news administrators who spend an inordinate amount of
time editing their news config files at the behest of the sites they
feed. In fact, once gup is installed, it is quite likely that manual
edits of your ‘‘newsfeeds’’ or ‘‘sys’’ file will become a thing of the
Gup is designed to be installed as a mail-server program that is fed an
inbound mail via stdin. Gup is usually invoked from a .forward file.
Each site has an entry in the ‘‘config’’ file containing password and
mail address details and a group selection file called ‘‘groups’’, see
CONFIG, and GROUPS for more details.
The news administrator of each site mails commands to gup. There are
commands to include and exclude group patterns, list the current
patterns for that site and list the available newsgroups; see COMMANDS,
for more details.
The results are normally mailed back to the site’s configured
administrator. However under some circumstances, the results are
mailed to the originator or the local administrator; see PROCESSING,
for further details.
Gup does not directly change the news system’s control files (eg,
‘‘newsfeeds’’ for INN). Instead a trivial shell script must be run to
concatenate all of the changed ‘‘groups’’ files together into an
appropriately formatted file for your particular news system. (One is
provided in the source kit for INN).
Since each site has to be specifically configured in gup’s ‘‘config’’
file, access can be restricted to administrator’s capable of managing
their own group patterns.
Options can appear in any order on the command line. The most important
point to note is that all of the paths and directories defined will
normally be absolute paths unless you are intimately familiar with the
way in which gup changes directories as it processes a mail (the
possible exception here is the Sites_directory).
The path of the active file for your news system. Before
accepting any newsgroup identified in a command, gup validates
the group against the active file. The command is rejected if no
match is found.
Defines gup’s home directory. Gup changes to this directory as
soon as possible after starting up. If this option is not
present, the current directory is used. Gup looks for the
‘‘config’’ file in it’s home directory.
-h Print out a help message showing the command line options, then
A record of all significant requests are written to this file.
If the path is relative, then it will be relative to gup’s home
directory; see the -d option). Gup must be able to write to
this file. If the -l option is not used, then gup uses stderr.
This is useful for testing purposes, but is unlikely to be of
use in a .forward file.
When gup generates a mail response it only generates the ‘‘TO:
’’ header line. This option defines the path of a file that
contains other RFC882 conformant header lines that are piped to
the mail program (see the -M option). In fact, if this file
contains a body following the headers, then that will precede
any text generated by gup. If this path is not an absolute
path, then it will be treated as relative to gup’s home
directory (see the -d option).
Gup pipes the rfc822 headers and the body of the mail to the
nominated mail program. Normally, this is configured when gup is
installed, but it can be over-ridden with this option. The mail
command must be able to determine the recipient addresses from
the rfc822 headers.
If present, the newsgroups file is used to try and find a
matching description of newsgroup when listed.
-P Do not prune superfluous patterns from a site’s ‘‘groups’’ file.
Before writing the updated ‘‘groups’’ file, gup applies a fairly
rigorous test to the patterns, pruning any nonsensical or
un-necessary patterns. This pruning process can be quite CP
intensive to the extent that it may have a deleterious effect on
your system - thus the ability to disable it.
Each site’s ‘‘groups’’ and ‘‘exclude’’ file are located in a
unique directory for each site. These site directories are
located in the directory defined with this option. If this is
given as a relative path then it will be relative to gup’s home
directory (see the -d option). Gup will try and create this
directory if it does not exist.
-v Print out the version number and various compile-time variables,
Gup scans the body of the mail for commands. Blank lines are ignored
and any data after the ‘‘#’’ character is considered a comment. No
continuation is allowed. Many of the commands accept a pattern as a
parameter. This pattern is identical to the format of the wildmat()
pattern; see wildmat (3) ). In fact, Gup purposely uses the wildmat
routine from INN to ensure that the pattern matching characteristics
Valid commands are:
site sitename password
This must be the first command in the mail. sitename and
password must match an entry in the ‘‘config’’ file. Only one
site command is allowed per mail. Aliases: "open" and "host".
quit This command stops gup from processing the rest of the mail.
This is useful if your mail User Agent tends to automatically
append a signature file to your mail. Alias: "q".
The pattern is checked against the active file. If it matches at
least one newsgroup, the pattern is placed at the end of the
site’s ‘‘group’’ file as an include entry. Only one pattern per
include command is allowed. If the pattern matches anything in
the site’s exclusion list (see EXCLUSIONS) then the include will
fail. Aliases: "+" and "inc".
The pattern is checked against the active file. If it matches at
least one newsgroup, the pattern is placed at the end of the
site’s ‘‘group’’ file as an exclude entry. Only one pattern per
exclude command is allowed. Aliases: "-" and "exc".
If the pattern matches at least one crossposted newsgroup the
article will not be accepted even if allowed by an include
statement. Only one pattern per poison command is allowed.
help Generate a small help message that briefly describes each
command. There is an implied quit with the help command so
there is no point in placing commands after the help command.
list list all of the current include and exclude patterns in the
sites ‘‘groups’’ file. The output is in a format suitable for
feeding back into gup at a later stage if need be. Alias: "l".
Delete all include, exclude and poison patterns in the site’s
‘‘groups’’ file that match the pattern. ‘‘delete *’’ is an
effective way of clearing all current patterns.
This command lists out all available newsgroups from the active
file that match the pattern. The list includes the description
from the newsgroups file as well as an indication if the site is
currently subscribed to that group. Only one pattern per
newsgroups command is allowed. Alias: "news".
Gup has a number of processing stages. The initialization stage
consists of changing to the home directory (see the -d option) and
opening the logfile (see the -l option). At this time, gup sets the
tentative reply-to mail address to the ‘‘backstop’’ mail address
defined when gup was compiled (typically the local news administrator).
The next stage consists of scanning the inbound mail, noting
interesting mail headers. The most interesting ones are "TO:" and
"REPLY-TO:". When a "TO:" header is found it becomes the tentative
reply-to mail address. If a "REPLY-TO:" header is found it over-rides
any "TO:" address to become the new tentative reply-to mail address. A
few others are noted and logged to help track changes.
After all the headers have been processed, the body of the mail is
examined for commands. The first command must be the site command. Any
other data results in an error mail sent to the tentative reply-to mail
address. If the site command contains a name that matches an entry in
the ‘‘config’’ file, then the tentative reply-to mail address is
replaced with the mail address in the ‘‘config’’ file.
The reason for these contortions with tentative reply-to mail addresses
is simply to deal with the problem of working out who to send a mail to
in the event of an error. Ideally they should all go back to the mail
address in the ‘‘config’’ file, but that information is not known for
quite a significant part of gup’s initial processing.
Once a valid site command has been accepted, gup changes to that site’s
directory in Sites_directory (see the -s option) making the
Sites_directory and site’s directory as necessary. The site’s directory
name is the same as the site’s name. In the absence of the -s option
this will be:
Where $HOME is gup’s home directory and $site is the name of the site
being processed. Gup locks the site then loads the site’s current
‘‘groups’’ file and any xclusion list if present (see EXCLUSIONS for
From this point on gup accepts any command in any order until either
the end of the mail, a quit command a help command or a serious error
during processing. After all commands have been processed, gup
update’s the site’s ‘‘groups’’ file if changes have been made. This
update includes pruning any superfluous patterns (unless the -P option
is used). Gup writes the new patterns to ‘‘groups.new’’. It then
renames ‘‘groups’’ to ‘‘group.old’’ and finally renames ‘‘groups.new’’
to ‘‘groups’’. The result of all this processing is mailed to the site
administrator defined in the ‘‘config’’ file.
Access to gup is controlled by the ‘‘config’’ file in gup’s home
directory (see the -d option). This file contains one line per site.
Each line contains three white-space separated tokens. The site’s name,
password and mail address of the administrator. Blank lines are
allowed and comments follow the ‘‘#’’ character. Gup uses a very
simple tokenizer, thus no quoting or continuation is allow in this
The site name and password are used to check an inbound site command.
The password can be crypted or in plain-text so permissions should be
carefully set to restrict access. Here’s an example of a ‘‘config’’
werple Fert5566a__$1 email@example.com
torps 34fkr_&&11)Zz firstname.lastname@example.org
uunet R_S_1@@*(A-\ email@example.com
.test flapper markd
Hopefully this is intuitively obvious...
Each site has it’s own file of patterns. This file is called ‘‘groups’’
and is located in the site’s own directory below the Sites_directory
(see the -s option). This file contains one pattern per line.
Exclusion lists have a preceding ‘‘!’’ character. Here’s an example:
Normally this file should only be changed by gup, but assuming you
cater for locking, there is no reason why some other process cannot
change it too. Whenever gup has to apply changes, it renames this file
to ‘‘groups.old’’ prior to re-writing the ‘‘groups’’ file. This gives
you some measure of recovery.
For whatever reason, you may wish to exclude particular groups from a
site’s selection list. You can do this by creating the file ‘‘exclude’’
in the site’s directory. This file contains newsgroup patterns, one per
line, that are used to filter the ‘‘active’’ file when verifying group
patterns. The effect of this is that gup believes that such groups do
not really exist, therefore a site cannot possibly include them.
All error conditions are record in the log file and possibly the
resultant mail - depending on the nature of the error. A particular
problem that is hard to detect is when the .forward file invokes gup
incorrectly. If gup is not invoked due to such an error, then
notification depends on the mailer. This should only be a problem to
watch out for when first installing gup.
Gup does not understand ‘‘Distribution patterns’’. Any such patterns
must be generated and maintained independently of gup.
Gup does not know when the popen(1) fails when Mail_command is invoked.
This is a limitation of popen(1). If the Mail_command is bogus, then
the error will be pretty obscure and dependent on your mailer. stderr
is redirected to the logfile prior to invoking the Mail_Command so
hopefully /bin/sh (used by popen) has generated an appropriate message.
Gup Version 0.3, dated 26 July, 1993.
Initially created by Mark Delany <firstname.lastname@example.org>.
Numerous enhancements and optimizations by Andrew Herbert
Currently maintained by Marco d’Itri <email@example.com>.
The wildmat.c is taken directly from the INN sources, written by Rich
The rfc822.[ch] parsing routines are taken directly from the newsgates
sources, also written by Rich Salz <firstname.lastname@example.org>.
25 July 1993