Provided by: inn2_2.7.2~20230806-1_amd64 
NAME
control.ctl - Specify handling of Usenet control messages
DESCRIPTION
The file pathetc/control.ctl is used to determine what action is taken when a control
message is received. It is read by controlchan, which is normally invoked as a channel
program by innd. When control.ctl is modified, controlchan notices this automatically and
reloads it.
If a control.ctl.local file exists in pathetc, it is read by controlchan after control.ctl
(the resulting behaviour is as though the contents of control.ctl.local were at the end of
control.ctl). This local file is formatted like control.ctl and is intended to contain
local customization. It is also automatically reloaded when modified.
Blank lines and lines beginning with a number sign ("#") are ignored. All other lines
should consist of four fields separated by colons:
<type>:<from>:<newsgroups>:<action>
Lines are matched in order and the last matching line in the file will be used, except for
checkgroups messages which are handled differently (every matching line is used).
The first field, <type>, is the type of control message for which this line is valid. It
should either be the name of a control message or the word "all" to indicate that it
applies to all control messages. Besides, the following special types are understood:
/encoding/
This type specifies the encoding of newgroup and checkgroups control messages so that
new descriptions could be decoded the right way.
/encoding/:*:cn.*:gb18030
means that a description for a newsgroup in the Chinese cn.* hierarchy will be
decoded as though it were encoded in GB18030, unless a charset is specified in the
control message (in such a case, the charset mentioned in the message is used).
However, it is possible to override the mentioned charset if "=force" is appended
after the encoding. For instance,
/encoding/:*:scout.forum.chinese:big5=force
means that the description for scout.forum.chinese will always be decoded as though it
were encoded in Big5, no matter the charset of the corresponding control message.
The default value when no encoding is mentioned (or when the specified encoding is
unknown) is "CP1252".
The last matching line for a given newsgroup name in control.ctl will be used.
/localencoding/
When this type is used, the line consist of only two fields. The default value when
this type does not appear in control.ctl (or when the specified charset is unknown) is
equivalent to:
/localencoding/:utf-8
It means that new descriptions in the newsgroups file will be written using UTF-8.
And controlchan will try to read existing descriptions, so as to see whether they
should be updated, as though they were encoded in UTF-8.
The last matching line in control.ctl will be used.
/maxdocheckgroups/
This type specifies the maximum number of changes that could be made at one time by a
checkgroups before bailing and mailing the changes to the admin if no log file was
specified. The default value is 10.
/maxdocheckgroups/:*:*:10
/maxdocheckgroups/:*:fr.*:20
Such a configuration means that a checkgroups containing 15 changes for the French
fr.* hierarchy (newgroups to add, remove or change the status) will be automatically
honoured whereas a checkgroups containing 15 changes for france.* will only have the
required changes mailed or logged.
The last matching line for a given newsgroup name in control.ctl will be used.
The second field, <from>, is a shell-style pattern that matches the e-mail address of the
person posting the message (with the address first converted to lowercase). The matching
is done with rules equivalent to those of the shell's case statement; see sh(1) for more
details.
If the control message is a newgroup or rmgroup, the third field, <newsgroups>, is a
shell-style pattern matching the newsgroup affected by the control message (especially "?"
matches exactly one character, "*" matches zero or more characters and "|" permits
matching several patterns on the same line -- for instance "comp.*|humanities.*" matches
every newsgroup whose name begins with "comp." or "humanities."). If the control message
is a checkgroups, the third field is a shell-style pattern matching the newsgroups that
should be processed for checking. If the control message is of any other type, the third
field is ignored.
The fourth field, <action>, specifies what action to take with control messages that match
this line. The following actions are understood:
doit
The action requested by the control message should be performed. It means that the
change will be silently performed. For checkgroups messages, depending on the value
of /maxdocheckgroups/, the shell commands that should be run may be mailed to the news
administrator (the argument to --with-news-master given at configure time, "usenet" by
default) instead of being performed.
If you always want notification of actions taken, use "doit=mail" instead (see below).
doit=file
The action is performed as in doit, and additionally a log entry is written to the
specified log file file. If file is the word "mail", the log entry is mailed to the
news administrator instead. An empty string is equivalent to /dev/null and says to
log nothing.
If file starts with a slash, it is taken as the absolute filename to use for the log
file. Otherwise, the filename is formed by prepending pathlog and a slash, and
appending ".log". In other words, an action of "doit=newgroup" will log to
pathlog/newgroup.log.
drop
No action is taken and the message is ignored. For checkgroups messages, it means
that the newsgroups mentioned will be considered as not existent in the checkgroups
for its subsequent process.
checkgroups:*:comp.*:doit
checkgroups:*:*binaries*:drop
will for instance remove every newsgroup whose name contains "binaries" in the comp.*
hierarchy, even though such groups are mentioned in the checkgroups. (In that
example, the removal is performed by the doit action because drop does nothing by
itself.)
verify-*
If the action starts with the string "verify-", as in:
verify-news.announce.newgroups
then PGP verification of the control message will be done and the user ID of the key
of the authenticated signer will be checked against the expected identity defined by
the rest of the string ("news.announce.newgroups" in the above example). This
verification is done via pgpverify; see pgpverify(1) for more details.
If no logging is specified (with =file as mentioned below), logging will be done the
same as with doit as described above.
verify-*=mail
PGP verification is done as for the verify-* action described above, and notification
of successful newgroup and rmgroup control messages and the output of checkgroups
messages will be mailed to the news administrator. (In the case of checkgroups
messages, this means that the shell script that should be run will be mailed to the
administrator. The subject of the mail will contain information on whether the script
has already been run, depending on the value of /maxdocheckgroups/.)
verify-*=file
PGP verification is done as for the verify-* action described above, and a log entry
is written to the specified file as described in doit=file above. (In the case of
checkgroups messages, this means that the shell script output of the checkgroups
message will be written to that file. The initial line of the log will contain
information on whether the script has already been run, depending on the value of
/maxdocheckgroups/.)
log A one-line log message is sent to standard error. innd normally directs this to
pathlog/errlog.
log=file
A log entry is written to the specified log file, which is interpreted as in doit=file
described above.
mail
A mail message is sent to the news administrator without taking any other action.
One of the difference between a doit or verify action and a mail action for a checkgroups
control message lies in what e-mail is sent; doit or verify will mail the news
administrator a shell script (which may have already been run) to create, delete, or
modify newsgroups to match the checkgroups message, whereas mail will just mail relevant
lines of the checkgroups for manual processing by the news administrator.
Use of the verify action for processing newgroup, rmgroup and checkgroups messages is
STRONGLY recommended. Abuse of control messages is rampant, and authentication via PGP
signature is currently the only reliable way to be sure that a control message comes from
who it claims to be from. Most major hierarchies are now issuing PGP-authenticated
control messages.
In order to use verify actions, the PGP key ring of the news user must be populated with
the PGP keys of the hierarchy maintainers whose control messages you want to honour. For
more details on PGP-authenticated control messages and the URL for downloading the PGP
keys of major hierarchies, see pgpverify(1).
Control messages of type cancel are handled internally by innd and cannot be affected by
any of the mechanisms described here.
EXAMPLES
With the following three lines in control.ctl:
newgroup:*:*:drop
newgroup:group-admin@isc.org:comp.*:verify-news.announce.newgroups
newgroup:kre@munnari.oz.au:aus.*:mail
a newgroup coming from "group-admin@isc.org" will be honoured if it is for a newsgroup in
the comp.* hierarchy and if it has a valid signature corresponding to the PGP key with a
user ID of "news.announce.newgroups". If any newgroup claiming to be from
"kre@munnari.oz.au" for a newsgroup in the aus.* hierarchy is received, it too will be
honoured. All other newgroup messages will be ignored.
Besides, if a control.ctl.local file exists and contains:
newgroup:*:comp.lang.*:drop
then a newgroup control article for comp.lang.awk will not be honoured even though it
comes from "group-admin@isc.org" with a valid signature.
As for checkgroups, suppose your news server contains these groups for foo.*, all of them
being unmoderated ("y" status in the active file):
foo.bar1
foo.bar2.first
foo.bar2.second
foo.bar2.third
foo.bar3
foo.bar3.first
foo.bar3.second
foo.bar5
and you receive the following checkgroups by <foo@bar.com> for foo.*:
foo.bar1 A valid newsgroup.
foo.bar3.first Only one newsgroup in foo.bar3.*.
foo.bar4 A newsgroup you want.
foo.bar5 A newsgroup you do not want.
foo.bar5.first Another newsgroup you do not want.
with the following control.ctl entries:
/maxdocheckgroups/:*:foo.*:2
checkgroups:foo@bar.com:foo.*:verify-key-foo
checkgroups:foo@bar.com:foo.bar2.*:doit
checkgroups:foo@bar.com:foo.bar3.*:mail
checkgroups:foo@bar.com:foo.bar4|foo.bar4.*:doit
checkgroups:foo@bar.com:foo.bar5|foo.bar5.*:drop
Then, as control.ctl is processed from bottom, here is what happens:
1. The newsgroups foo.bar5 and foo.bar5.first are marked as unwanted. But nothing is
done yet: other control.ctl entries have to be processed with a real action and a set
of newsgroups containing foo.bar5 and foo.bar5.first.
2. The newsgroup foo.bar4 is silently created on the news server, with the description "A
newsgroup you want." added to the newsgroups file. In the absence of encoding values
(either in the checkgroups message or in /encoding/ and /localencoding), the default
is to decode the sentence as CP1242 and re-encode it as UTF-8.
If "doit=mail" was used, a mail would be sent to the news administrator to inform him
that foo.bar4 was successfully created.
3. The newsgroup foo.bar3.second is no longer present. A mail is sent to the news
administrator with a shell script to execute. When it is manually executed,
foo.bar3.second will be removed.
Note that the descriptions are handled differently and have already been updated
without any manual intervention (foo.bar3.first now has the description "Only one
newsgroup in foo.bar3.*." and foo.bar3.second no longer has a description).
4. The newsgroups foo.bar2.first, foo.bar2.second and foo.bar2.third are no longer
present. However, as the maximum number of changes that could be made at one time by
a checkgroups before bailing and mailing the changes to the news administrator is 2,
these newsgroups are not removed. A mail is sent with a shell script to manually
execute in order to remove these groups from the news server.
Note that their descriptions are removed from the newsgroups file, as well as any
other possible descriptions for obsolete newsgroups in foo.bar2.*.
5. The remaining entry is executed if the PGP verification of the checkgroups message is
successful. Otherwise, nothing is done (especially, foo.bar5 remains on the news
server).
In case the PGP signature is verified, foo.bar3 and foo.bar5 are removed from the news
server. This entry acts upon newsgroups marked as dropped in its scope and newsgroups
not already dealt with by previous control.ctl entries (like foo.bar3 because only
foo.bar3.* was previously checked).
Note that if you had wanted to keep foo.bar3 or foo.bar5, you could have added them to
the localgroups file in pathetc.
HISTORY
Written by Rich $alz <rsalz@uunet.uu.net> for InterNetNews. Rewritten in POD by Russ
Allbery <eagle@eyrie.org>.
SEE ALSO
controlchan(8), inn.conf(5), innd(8), newsfeeds(5), newsgroups(5), pgpverify(1), sh(1).