Il CD di internet/CD.iso/SOURCE/N/CNEWS/_CNEWS.TAR/usr/doc/cnews/docs/install

Text File | 1994-09-02 | 22.3 KB | 975 lines

.Ch "Installing ``C News'' Network News Software"
.SH
Introduction
.Ix introduction
.PP
.Df news
.Df netnews
.Df "network news"
Network news
(or
.I netnews
for short)
consists of a collection of messages formatted similarly to
ARPAnet mail
(see DARPA RFC 1036 for details),
.Ix "RFC 1036"
widely spread.
The logical network,
imposed on top of various real networks,
formed by the set of all interconnected sites
exchanging network news is called
``Usenet''
.Df Usenet
and was formed in 1979,
radiating out from Duke University.
Netnews is propagated
between cooperating machines
by a flooding algorithm,
with some loop prevention heuristics:
each machine sends its neighbours news that the
neighbours have (probably) not yet seen.
.PP
Flow of netnews between machines
may be achieved by use of any network
(or other medium)
which can transmit an arbitrary stream of
(at least 7-bit,
preferably 8-bit)
ASCII code, unmodified.
If a network cannot transmit ASCII intact
(e.g. BITNET),
it is possible to encode netnews
before transmission across the network
and
decode it upon reception from the network.
Since one cannot be certain that
one's network neighbours will be up and
reachable at all times,
outgoing netnews must be queued,
at least in the case of network trouble.
To date,
at least
these networks,
protocols and media
have been used to transmit netnews correctly:
UUCP,
.Ix UUCP
RS232,
NNTP,
.Ix NNTP
Ethernet\(rg,
the ARPA Internet,
.Ix Internet
Datakit\(rg,
.Ix Datakit
ACSnet,
.Ix ACSnet
magnetic tape,
SMTP,
and
BITNET,
though at least the last two require some form of encapsulation
to avoid corruption of articles;
SMTP because some common implementations get the newline-CRLF
mappings wrong,
thus throwing off byte counts in batches,
and
BITNET because of its Procrustean chopping,
.Ix BITNET
expanding,
mapping,
bashing
and
smashing
of all data sent through it
(sending lines of 80 or fewer characters of
letters of either case and digits and plus and minus
appears to be safe).
.PP
Netnews arrives via some network,
which causes a command to be executed upon arrival
(e.g.
.I rnews ).
.I rnews
.Ix rnews
typically spools the inbound netnews for later processing.
Eventually
(often within the hour
or at the end of the business day),
the input queue is run
and the netnews is stored locally,
typically under
.I /usr/spool/news ,
.Ix /usr/spool/news
and queued for transmission to netnews neighbours.
Once stored on disk,
netnews may be read by any of a collection of unprivileged news readers,
including
.I cat (1).
.I Expire
.Ix expire
is run typically each night
to remove old netnews from disk.
.PP
C News
.Df "C News"
was originally written to provide a
much faster and smaller,
more robust,
reliable
and
correct
implementation of netnews software than B 2.11 news.
.Ix "B 2.11 News"
(There was once a B 3.0 news under development;
it seems to be still-born.)
.Ix "B 3.0 News"
.SH
News System Overview
.PP
News is stored under some directory,
referred to as
NEWSARTS,
which is typically
.I /usr/spool/news .
.Ix NEWSARTS
.Ix /usr/spool/news
Each newsgroup is stored in its own directory,
whose name is formed by replacing all dots in the newsgroup name
with slashes.
Each article is stored in a file with a numeric name.
There are pseudo-newsgroups
called
.Ix junk
.Ix control
.Ix pseudo-newsgroups
.I junk
and
.I control
which respectively hold
articles that your subscription list in the
.I sys
.Ix sys
.Ix files sys
file permitted but which aren't in your
.I active
.Ix active
.Ix files active
file,
and control messages.
There are also directories called
.I in.coming ,
.I out.going ,
and
.I out.master ;
.Ix in.coming
.Ix out.going
.Ix out.master
they hold incoming news,
outgoing news batch files
and
outgoing master batch files.
.I in.coming
contains temporary files with various names
and spooled input files with numeric names.
.I out.going
contains one directory per outgoing news feed
(more for ihave/sendme sites).
.PP
Indices and related data
are stored in another directory,
referred to as
NEWSCTL,
usually
.I /usr/lib/news .
.Ix /usr/lib/news
.Ix NEWSCTL
Some of the interesting files here include
.I active ,
.I active.times ,
.I explist ,
.I history ,
.I sys
and
.I bin/config .
There are also log files kept here,
notably
.I log
and
.I errlog ,
which need to be aged or trimmed frequently
(our standard
.I cron
entries do this automatically).
.I newsgroups
contains a list of group names and descriptions,
one per line.
.SH
C News Components.
.PP
.I Rnews
.Ix rnews
invokes
the input subsystem,
.Ix "input subsystem"
which
spools incoming netnews in its original form,
as received
(usually from
.I uucp
or
.I NNTP ),
typically in compressed batches.
Periodically,
the input queue should be run
by invoking
.I newsrun ,
.Ix newsrun
thus uncompressing any compressed input
and feeding it to
.I relaynews .
.Ix relaynews
.PP
.I inews
.Ix inews
is a front-end for
.I relaynews
which implements much of the per-site policy on news posting.
Local postings are given to
.I inews .
.PP
.I Relaynews
.Df relaynews
files incoming netnews as articles on disk
and
initiates spooled transmission to other machines,
often by simply writing the names of the disk files
containing the articles on the ends of `batch' files,
which are in turn read by batching programs.
.Ix batch
Quite a bit of policy from RFC 1036 is embedded in
.I relaynews .
Actually,
.I relaynews
writes
`master batch files',
which the batch file exploder,
.I explode ,
turns into normal batch files.
.I explode
should be run periodically from
.I cron
or
.I newsrun .
.PP
The output
.I batcher
.Df batcher
reads lists of file names
and
generates news batches
(see RFC 1036 or
.I news (5)
for the format)
of prescribed sizes
and queues the batches
for transmission to other sites.
The batcher is run asynchronously with
.I relaynews ,
typically once an hour
outside of business hours.
NNTP sites
will also need to run an NNTP transmitter
periodically
(e.g.
.I nntpxmit
or
.I nntplink ).
.PP
.I Expire
.Ix expire
is generally run once per night
to remove from disk news articles older than a few days.
.I Expire
can use different expiry criterion for different newsgroups
and can archive articles instead of removing them.
.I Expire
also runs asynchronously
with
.I relaynews .
.PP
Some people start their news processes from
.I newsxd
rather than
.I cron ;
we don't,
and so can't offer much advice.
.PP
There are many news readers.
.Ix "news readers"
C News
comes with a limited news reader
(\c
.I readnews
.Ix readnews
.Ix "news readers" readnews
by Michael Rourke)
sufficient to replace
long-winded
.I /etc/motd s
but you will want a heavy-duty news reader
if you plan to read more than local news groups.
We recommend
.I rn
.Ix rn
.Ix "news readers" rn
by Larry Wall
or
.I nn
.Ix nn
.Ix "news readers" nn
by Kim Storm,
available from
your netnews neighbours
or
your nearby
.B comp.sources.unix
.Ix comp.sources.unix
archive site.
There are many others:
.I trn
.Ix trn
.Ix "news readers" trn
and
.I vnews
.Ix vnews
.Ix "news readers" vnews
are two.
News can be read from the local disk,
via a network file system such as NFS,
.Ix NFS
or via
NNTP
.Ix NNTP
(soon to be NNRP).
.Ix NNRP
.SH
Preparation for Installation
.PP
Netnews consumes a lot of disk space
and
often a lot of transmission time.
Here are some relevant measurements regarding a full netnews feed
as of the time of writing
.Ix news size
.Ix news statistics
.\" (January 1989),
(February 1992),
taken from
.I news.lists :
a day's netnews is about
.\" 3MB and 1,400 articles in 450 newsgroups.
30MB and 10,000 articles in 3,000 newsgroups.
Groups cover every imaginable topic,
and there are for-pay hierarchies such as
.B clari ,
which provide the UPI news wire.
Years ago,
sites often kept 14 days of netnews on disk,
but now many sites keep news for 3 to 5 days,
thus allowing for the occasional long weekend.
.Ix expire policy
Thus a full news feed expired after 4 days will consume
.\" about 12MB.
about 120MB.
Some people feel that news volume is doubling roughly every
.\" 16 months.
12 months.
If this is true,
we can expect volume to increase by a factor of 10 in about
.\" 4 years to 30MB per day or 115MB for 4 days.
3 years to 300MB per day or 1.2GB for 4 days.
It is thus wise planning to set aside a lot of disk space for netnews.
There are two ways to cope with ever-increasing volumes of netnews:
refuse to accept more newsgroups,
or
expire news after shorter intervals on disk.
A current full feed takes
.\" just over 7 hours to transmit at 1200 baud,
.\" so for dial-up connections
.\" one clearly wants the fastest modems one can afford.
about 16 hours to transmit at 9600 bps
(assuming only 500 bytes per second actually sent),
so for dial-up connections,
2400 baud and below is right out.
.Ix "full feed" times
In 4 years,
a 56kbps ISDN channel should be saturdated around the clock by a full feed.
.Ix ISDN doomed
One clearly wants the fastest networks one can afford.
.PP
.Ix news feed
Clearly,
transmitting a full news feed is a non-trivial commitment of resources,
so you may have some difficulty in finding a site willing to supply one.
Such a site may in turn expect you to feed yet other sites.
You will need to agree with your prospective netnews neighbour(s)
upon transfer media,
protocols
and
networks.
You can always pay for a news feed from service providers such as
UUNET and PSI.
.Ix UUNET
.Ix PSI
.PP
Before proceeding to install C News,
you should read this document through
to the end,
probably read the companion document
\fIThe Interface Between C News And The Outside World\fR,
and possibly read selected items in this guide
and the manual pages.
.PP
.Ix userids
You will need to
assign a user id and group id to netnews
(often new ids called ``news'');
initialise these directories:
.Ix directories
NEWSCTL
.Df NEWSCTL
(typically
.B /usr/lib/news ),
.Ix /usr/lib/news
NEWSBIN
.Df NEWSBIN
(\c
.B /usr/lib/newsbin ),
.Ix /usr/lib/newsbin
and
NEWSARTS
.Df NEWSARTS
(\c
.B /usr/spool/news );
.Ix /usr/spool/news
and
install each subsystem
(each subdirectory of
NEWSBIN
contains the programs for a given subsystem).
NEWSCTL and NEWSARTS
are logically one subtree,
defining a news data base,
but are split for backward compatibility with
older news software,
particularly old news readers.
NEWSBIN
contains programs and shell scripts
which might be common amongst machines sharing
a common architecture
(e.g. Sun 3's);
.Fn NEWSCTL /bin
may override these.
The goal is to install the subsystems,
integrate them into a working news system,
and
configure the news system to communicate with other news systems.
.PP
.Ix files key
There are a few key files that must exist before any serious
attempt may be made to operate the news software.
They all live in
NEWSCTL.
.Ix NEWSCTL
.Fn "" active
.Df files active
.Df active
is the list of newsgroups that this site knows
(is willing to accept or individually reject),
and must be owned by the
NEWS
userid
(the userid that owns
.Fn NEWSBIN /relay/relaynews ,
typically
.I news ).
You will probably want to get your initial
.Fn "" active
file from your upstream feed
and edit it to suit the set of groups you wish to receive.
Be sure to make the second field more than five digits wide,
by adding leading zeroes
(ten digits is a conservative width).
.Fn "" sys
.Df files sys
.Df sys
defines the newsgroups that this site is willing to accept
and describes how they are to be forwarded to its neighbours.
.LG
.B Note:
.NL
Your
.B sys
file is required,
as a cost of membership in Usenet,
to be public information.
It will be sent to anyone who requests it via a
.I sendsys
control message.
Don't put secrets in your
.B sys
file.
.Df files server
.Df server
.Fn "" server
contains the hostname of your file server,
if you have multiple machines sharing news
via a network file system.
.Fn "" whoami
.Df files whoami
.Df whoami
similarly contains the name by which a cluster of machines
sharing news is to be known for purposes of news.
.Fn "" mailname
.Df files mailname
.Df mailname
is optional and contains the full
(possibly dotted)
name by which your cluster is known for purposes
of mail.
.Fn "" organisation
.Df files organisation
.Df organisation
.Df files organization
.Df organization
(or
.Fn "" organization
if you insist)
contains the name of your organisation,
which will be copied into the
.B Organization:
.Ix Organization:
header of articles posted locally,
by default.
.Fn "" mailpaths
.Df files mailpaths
defines mail routes to machines which contain aliases
for postings to moderated newsgroups.
.Fn "" log ,
.Df files log
.Df log
.Fn "" errlog ,
.Df files errlog
.Df errlog
.Fn "" history ,
.Df files history
.Df history
.Fn "" history.dir ,
.Df files history.dir
.Df history.dir
and
.Fn "" history.pag
.Df files history.pag
.Df history.pag
must exist and be owned by the
NEWS
userid.
.Fn "" explist
describes local expiration policy;
N.B.:
the order of lines is significant
and
articles with
.B Expires:
headers can interfere:
read
.I expire (8)
for the full story.
Brian Reid's
.I arbitron
script can be run to get
some idea of what groups your users actually read.
.I expire
can be made to archive articles before removing them.
Tentative versions of all these files are built by the installation
procedures,
but it is quite likely that you'll have to edit some of them.
.SH
C News Installation
.PP
.Ix installation
Proceed to the
.Fn \& conf
directory of the distribution.
There is a major shell file here,
named
.Fn \& build ,
.Ix build
that will interrogate
you at length and construct shell files to do the real work.
You may need to do
``chmod\ +x\ build'' before running it,
to make it executable.
.PP
You will probably need your system's manuals on hand to answer
.Fn \& build 's
questions.
Another terminal (or another window, on a bitmap display)
would also be useful.
You'd best be prepared to take notes,
also, as
.Fn \& build
will occasionally suggest that something be checked when you're done.
.PP
.Fn \& Build
itself does not alter any files or perform any installation
chores:
all it does is create shell files in the
.Fn \& conf
directory.
If you already know something about news software,
or are merely
suspicious that
.Fn \& build
hasn't done everything right,
you should
probably read the shell files before running them.
There are four of them:
.Fn \& doit.root ,
.Ix doit.root
.Fn \& doit.bin ,
.Ix doit.bin
.Fn \& doit.news ,
.Ix doit.news
and
.Fn \& again.root .
.Ix again.root
.PP
.Fn \& Doit.root
sets up the major directories for news, and sets their
ownerships correctly.
It typically will have to be run as \fIroot\fR to have adequate permissions
for all of this.
It is brief.
.PP
.Fn \& Doit.bin
does most of the work of building and installing the programs.
It should be run as the user who owns the distribution directories and will
own the executable programs under NEWSBIN.
.B "doit.bin -i"
suppresses installation.
.Fn \& doit.bin
adds creates prototype additions to
.I crontab
.Ix crontab
.Ix files crontab
and
.I /etc/rc
.Ix /etc/rc
which run
.I newsrun ,
.I sendbatches ,
.I doexpire ,
.I newsdaily
and
.I newswatch
periodically,
and
clear out the news system at boot time,
respectively.
.PP
.Fn \& Doit.news
does some other small chores and installs control files.
If any of the control files already exist, it will complain and refuse
to overwrite them, as a safety precaution.
It should be run as the owner of the news files.
Since many of the files it is installing are built by
.Fn \& doit.bin ,
that should be run first.
.PP
Finally,
.Fn \& again.root
tends to ownership and permission changes on
a few programs that need to run set-userid.
It requires the ability to change ownerships and to set permissions on
the files afterwards, which usually means running it as \fIroot\fR.
It too is brief.
.PP
There are undoubtedly strange systems out there that
.Fn \& build
and friends are not smart enough to cope with.
In such cases it will be necessary to edit the shell files before running
them, or to use them as guides and do the work by hand.
In particular, systems that require strange options in
.Fn \& Makefile s
.Ix makefile
will need to have those inserted by hand.
.PP
.Ix "regression testing"
If you want to test pieces of C News without installing them, some
(not all) of the subsystems have a ``make\ r'' feature that runs a
regression test.
Note:  almost all of these require that
.Fn NEWSCTL /bin/config ,
.Ix files config
.Ix config
or its local equivalent, be in place already so that shell files
can find out what PATH (etc.)
they should be using.
.PP
.Ix system test
.Ix "test system"
Note that it is easy to build a test news system which is completely
independent of other existing news systems on the same machine,
or
to build one which shares its
.Fn NEWSBIN ""
with another C news system,
or shares input of articles
(e.g. running an old B news system
and a new C news system off the same stream of input
until you are confident that your new C news system is operating
to your satisfaction).
See
.I subst (1)
.Ix subst
for the mechanism which permits quickly changing
all the places that know the location of
.Fn NEWSCTL /bin/config.
After that,
edit this news system's
.Fn NEWSCTL /bin/config
and things should be set up for separate existence.
.SH
Local policy
.PP
You may want to edit the
.Ix newgroup
.Ix rmgroup
.I newgroup
and
.I rmgroup
scripts to change group creation and deletion policy.
By default,
all
.I newgroup
control messages are honoured,
but
.I rmgroup
messages merely cause mail to be sent to
NEWSMASTER.
Some sites prefer to not honour
.I newgroup
messages automatically,
which can cause articles to be filed
in the
.I junk
pseudo-group until the group is created by hand.
Very few sites honour
.I rmgroup
messages automatically,
since one is then at the mercy of pranksters.
Groups can be created and deleted manually with the
.I addgroup
and
.I delgroup
.Ix addgroup
.Ix delgroup
commands.
.SH
First News
.Ix "initial news"
.PP
When you arrange to get a news feed from your neighbor,
you should also
ask him to send you the current set of articles in the newsgroup
\fBnews.announce.newusers\fR.
.Ix news.announce.newusers
Several of these are very important reading for people who are new to the net.
.SH
Unusual Systems
.PP
We believe that C News runs fine on 16-bit machines, but it hasn't been
tested very thoroughly on them lately.
It will not perform quite as well with the more limited space.
.Ix "small machines"
.PP
Machines with very old compilers can be a headache.
.Ix "old compilers"
There are some hooks in
.Fn \& h/news.h
for doing without ``void'' and ``unsigned long'',
two particular problem areas, but they have to be arranged manually;
.Fn \& build
does not know about them.
.PP
Some very old systems cannot do \fIsetuid(geteuid())\fR, which makes it
impossible for a daemon to make directories and get the ownership right.
We provide a small program,
.Fn \& setnewsids ,
to run setuid-root.
.Ix setnewsids
.Fn \& Relaynews
knows about it and invokes it if \fIsetuid(geteuid())\fR fails;
it then sets permissions correctly and re-invokes
.Fn \& relaynews .
.Ix relaynews
The code is short enough to be read and understood in full, so that the
suspicious system administrator can be sure that this setuid-root program
is not going to do something awful.
.SH
Problems
.PP
In general,
you should consult
.I "Troubleshooting C News"
if you have problems,
and then
.I "Known Porting Problems With C News"
if that isn't sufficient.
Serious errors in relaying are reported in
.Fn NEWSCTL /errlog
and will be mailed to NEWSMASTER
eventually.
C News
generally communicates with the news administrator
(NEWSMASTER)
by mail.
One common complaint is that there is a space shortage
and incoming news has been discarded;
the usual fix for this is to run
.I doexpire
immediately.
One could modify
.I newsrun
to start a
.I doexpire
when space gets low.
.\" TODO: more of this sort of thing
.PP
It may be necessary to cancel a message posted in error by a user
who can't figure out how to cancel it himself.
Posting a message like this:
.DS
.ft B
inews -h <<'!'
Newsgroups: what.ever
Distribution: where.ever
Control: cancel <user's-article's-message-id>
Subject: cancel <user's-article's-message-id>

text.
!
.ft
.DE
should do the job.
.PP
You may see complaints in
.Fn NEWSCTL /log
that articles have been rejected for bad headers.
These will usually be from other sites,
as
.I inews
will correct most such errors for your users.
The usual errors are
(a) text immediately following the colon after the header keyword,
with no intervening space,
(b) a new line immediately following the colon,
or
(c) no blank line separating the message header from the message body.
.SH
Routine Maintenance
.PP
You can add an outgoing news feed by adding a line to your
.Fn NEWSCTL /sys
file for the new site
and creating its batch directory
(\c
.Fn NEWSARTS /out.going/ site).
.PP
As news volume grows,
you may need to ask your upstream feed to cut back on the groups it
sends you,
both to conserve network bandwidth
and disk space.
You will likely also need to either
cut back the length of time you keep news on disk before
expiry,
or get in the habit of buying new disks periodically.
.PP
See the article
.I "How to set up the mailpaths file"
by Gene Spafford
in
.I news.lists
for advice on same.
.PP
You can turn off news processing by running
.Fn NEWSBIN "/input/newsrunning off"
and restore it by running
.Fn NEWSBIN "/input/newsrunning on".
Neither takes effect instantly;
you have to wait for news processing to stop
and
wait for
.I newsrun
to be run for it to resume.
You might want to turn off news processing
before locking the news system to perform
lengthy work on it;
turning off processing both reduces the time until
you get the lock,
and
reduces disk load due to lock contention while you have the lock.
.PP
You will get mail due to a
.I checkgroups
control message periodically,
with a subject of
.I "Problems with your active file" ;
don't worry about it.
Some day
.I checkgroups
will get fixed and then you can worry.
.PP
You will probably want to read the
.I news.admin ,
.I news.software.b ,
.I news.lists
and possibly
.I news.groups
newsgroups to keep current.
.PP
Gatewaying mail to news and vice versa is not yet
a solved problem.
The most severe problem here is loop prevention.
If you reject articles that lack valid RFC 1036
.Ix "RFC 1036"
message-ids,
just running RFC 822 mail messages
.Ix "RFC 822"
into
.I "inews -h"
should suffice to gateway into news.
Gatewaying news back to mail should just require a
.Fn NEWSCTL /sys
file entry like
.DS
.ft B
mail:sci.space/all::mail victims
.ft
.DE
.bp
.SH
Sample build run
.\" can't use .DS L here cuz it starts a new page in this case.  grr...
.LP
.nf
.ft B\" should really be CW or C, but not everyone has it
.so build.script
.ft
.fi
.LP