Il CD di internet/CD.iso/SOURCE/N/CNEWS/_CNEWS.TAR/usr/doc/cnews/docs/b-to-c

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.Ch "B News to C News Transition Guide"
.Ix "B News to C News transition"
.SH
Preface
.PP
We describe the changes in installation
and administration from B News to C News.
The intended audience is B News administrators
switching to C News.
.SH
Introduction
.PP
.Ix history
.Ix "C News" history
.Ix history "C News"
C News was written by two people
.Ix authors
(Geoff Collyer
and
Henry Spencer)
who were experienced B News administrators
(since 1982).
C News was intended to be a much faster and more correct
B News
with some of the things that irritated us in B News changed.
C News is thus administratively similar to B News,
though not identical.
We have no personal experience running B News later than
2.10.1,
.Ix "B News 2.10.1"
and thus may have missed subtleties in later releases,
notably 2.11.
.Ix "B News 2.11"
.PP
The single largest visible change from B News is probably
that we wanted to allow the possibility of
machines of
different architectures sharing a single news data base
(\c
.I /usr/spool/news
.Ix /usr/spool/news
plus the data files in
.I /usr/lib/news
.Ix /usr/lib/news
in B News terms)
via network file systems
while keeping separate directories of executables elsewhere.
We did this by pushing the executables into a new directory,
often called
.I /usr/lib/newsbin .
.Ix /usr/lib/newsbin
We also took the opportunity to push most of the binaries into
subdirectories to reduce the clutter at the top level,
as the old B News
.I /usr/lib/news
had become awfully cluttered.
.PP
The next most visible change
is probably that we only compile in default values
for directory names
(and a few other configuration parameters),
but they can be overridden at run-time via environment variables
(subject to restrictions to prevent spoofing).
.I notebook/config
.Ix config
.Ix files config
(relative to the C News source subtree root)
describes the variables.
In a nutshell,
.I NEWSCTL
.Df NEWSCTL
is the equivalent of
.I /usr/lib/news
when referring to control files,
.I NEWSBIN
.Df NEWSBIN
is the equivalent of
.I /usr/lib/news
when referring to executables
(and is often
.I /usr/lib/newsbin),
and
.I NEWSARTS
.Df NEWSARTS
is the equivalent of
.I /usr/spool/news .
This capability can be used to run
B News
and C News
in parallel for testing,
.Ix "test system"
.Ix system test
feeding them identical inputs.
It can probably be used instead of the
.B IHCC
.Ix IHCC
ifdefs in B News.
It is also used for regression testing,
.Ix "regression testing"
when we run known input data through the software
in test directories
and verify that we get known results out;
.B "make r"
in a given source directory will generally invoke the relevant
regression test
and
.B "make rs"
in
.I conf
will invoke all of them.
.SH
Changes in control file formats
.PP
In general,
.I news (5)
.Ix "file formats"
.Ix formats file
now describes the file formats.
.PP
.I Sys
.Ix files sys
.Ix sys
adds a few optional features
and withdraws some old and little-used ones.
Many obsolete flags
draw fatal diagnostics,
notably
.B N ,
.Ix "N sys flag"
.Ix "sys flag" N
the old,
unbatched ihave/sendme flag.
The other unsupported flags are
.B A
.Ix "A sys flag"
.Ix "sys flag" A
(convert outgoing messages to
A News
.Ix "A News"
format;
.I relaynews
is not a protocol converter),
.B H
.Ix "H sys flag"
.Ix "sys flag" H
(append history entry to named file?;
sorry),
.B S
.Ix "S sys flag"
.Ix "sys flag" S
(duplicate the work of the shell to avoid one process;
just delete this flag),
.B M ,
.Ix "M sys flag"
.Ix "sys flag" M
and
.B O
.Ix "O sys flag"
.Ix "sys flag" O
.Ix multicast
(multicast flags;
obsoleted by the batcher,
as far as we can tell).
New flags are
.B f
.Ix "f sys flag"
.Ix "sys flag" f
(append spool file name and size in bytes to the named file)
and
.B n
.Ix "n sys flag"
.Ix "sys flag" n
(append spool file name and Message-ID to the named file;
equivalent to
.B FI
in
B News).
There have been some changes to flag semantics:
.B I
.Ix "I sys flag"
.Ix "sys flag" I
.Ix ihave/sendme
in B News
invoked all the ihave/sendme machinery
.I and
wrote message-ids to the batch file;
C News
just writes the message-ids.
See below for how to set up ihave/sendme feeds.
In
C News,
.B FI
and
.B I
are equivalent;
use
.B n
if you want file names and message-ids.
All file names written
are relative to
.I NEWSARTS .
.PP
B News
allowed comments to be continued;
this is at odds with all other
.UX
software,
including
C News.
To comment-out an entry under C News,
you need to prepend
`\c
.B # '
before
.I each
line of the entry,
not just the first.
.Ix "sys comments"
.Ix comments sys
.PP
There is now an optional
.I distributions
.Ix "distributions sys subfield"
.Ix sys distributions
list after the newgroups pattern,
separated by a slash.
If the fourth
.I sys
field is a relative command name,
.I NEWSCTL/bin
and
.I NEWSBIN/relay
will be searched before the standard search path.
If the fourth field is a relative file name,
.I NEWSARTS/out.going
will be prepended internally.
.Ix "batch files"
.Ix files batch
If the fourth field is an empty file name,
it will be replaced internally with
\fINEWSARTS/out.going/\fPsystem\fI/togo\fP
where
.I system
is the first field of the entry.
Note that although these batch files
live under
.I NEWSARTS ,
they are not news articles,
and their parent directories will
.I not
be automatically created.
.Ix ihave/sendme
The ihave/sendme kludges of B news
have been expunged;
one must say what one means.
See the section below on ihave/sendme.
.PP
.Ix active
.Ix files active
.I Active
has four fields
(there is vestigial code in some,
but not all,
programs for two or three fields)
and
any number of digits in the article-number fields
(five is too few for the long term).
Two new values are understood for the fourth
(flags)
field:
.B x ,
.Ix "x active flag"
.Ix "active flag" x
meaning
``quietly discard articles for this group'',
and
.B = realgroup
.Ix "= active flag"
.Ix "active flag" =
meaning
``file articles for this group under
.I realgroup
instead''.
.B =
is useful for coping with badly-run
local newsgroups,
often created from mailing lists.
.Ix "news system lock"
You must lock the news system with
.I locknews
before editing the active file.
.PP
.I History
.Ix history
.Ix files history
is in an extended
B 2.10 news
format:
the second field consists of two subfields
separated by a tilde:
time received as an integer (a
.I time_t
in fact),
and
the value of the
.I Expires:
header,
"-" if none.
More subfields may appear in future.
You must lock the news system with
.I locknews
.Ix "news system lock"
before editing the history file,
and
run
.I dbz (1)
.Ix dbz
(found in
.I NEWSBIN )
afterward to rebuild the index files.
.Ix "history index files"
.Ix files "history index"
.PP
.I Log
.Ix log
.Ix files log
and
.I errlog
.Ix errlog
.Ix files errlog
are only faintly similar to their B News counterparts.
Error processing in general is due for an overhaul,
which may further revise their formats.
Currently,
.I errlog
is the unadorned standard error from
.I relaynews (8)
.Ix relaynews
and any programs it runs.
.I Log
is a time-stamped log,
down to the millisecond
(where possible,
offer void where prohibited by
System V),
.Ix "System V" time
.Ix time "System V"
consisting of one line per article,
and
always showing the name of the host that handed us this article
and the Message-ID of this article.
See
.I "Log File Formats in C News"
for details.
.PP
Locks are in the style of B 2.10:
.I NEWSCTL/LOCK
.Ix "news system lock"
.Ix lock "news system"
is the news system lock,
but it never times out.
One locks the news system by repeatedly attempting
to link to the lock name until successful;
one releases the lock by removing the lock name.
There are other locks,
all of which begin with the prefix
.I NEWSCTL/LOCK .
This scheme works well over network file systems,
can be used from shell scripts and interactively,
permits one to
see trivially
what locks are present,
and is portable across
.UX
variants.
See
.I "Locking in C News"
for details.
.SH
`Missing' control files
.Ix "B News files" missing
.PP
.I Aliases
.Ix aliases
.Ix files aliases
does not exist,
since we believe that header munging is to be avoided
if at all possible
(we do update
.B Path: ,
regenerate
.B Xref: ,
and delete some large obsolete headers
[\c
.B Relay-Version: ,
.B Posting-Version: ,
.B Date-Received: ,
.B Received: ,
.B Posted: ,
.B Illegal-Object: ]).
It is possible to file articles locally under different newsgroups
by use of the
.I active
file
.B =
flag.
.PP
.I Notify
.Ix notify
is replaced by
.I NEWSMASTER
.Ix NEWSMASTER
in
.I NEWSCTL/bin/config .
.Ix config
.PP
.I Moderators ,
.Ix moderators
.Ix files moderators
.I recmail
.Ix recmail
and
.I recnews
.Ix recnews
are missing;
we don't know what they do (yet).
.PP
.I Seq
.Ix seq
.Ix files seq
is gone;
we don't need it.
.SH
New control files
.Ix "C News files" new
.PP
.I Batchparms
.Ix batchparms
.Ix files batchparms
controls outbound batching.
See
.I newsbatch (8).
.PP
.I Explist
.Ix explist
.Ix files explist
controls expiry policies.
The command-line options for
.I expire
are completely different from B News.
See
.I expire (8).
The simplest possible
.I explist
is
``\c
.B "all x 7 -" ''
for 7-day expiry of all articles
and
history entries.
.PP
.I Mailname
.Ix mailname
.Ix files mailname
is the domain name of this machine
for mail purposes;
.I whoami
.Ix whoami
.Ix files whoami
is the news name of this machine
(e.g. for
.B Path:
headers).
If
.I replyusepath
.Ix replyusepath
.Ix files replyusepath
exists,
automated mail replies will use the
.Ix "mail replies"
.Ix Path:
.B Path:
header for return addresses.
If
.I server
.Ix server
.Ix files server
exists,
.I inews
will
.I rsh
.Ix rsh
.Ix "remote command execution"
to the hostname found therein
to run
.I relaynews .
.Ix relaynews
.PP
.I Setnewsids
.Ix setnewsids
.Ix files setnewsids
is an optional setuid-root program
(in the wrong directory,
it appears)
to set user and group ids;
it should be obsolete now,
but instead
.SM
POSIX
.NL
.Ix POSIX
.Ix "System V"
and System V
are making it necessary all too often.
.SH
ihave/sendme feeds
.Ix ihave/sendme
.PP
We didn't understand the implementation of ihave/sendme
in B News for a long time and nearly didn't implement it,
having a very dim view of ihave/sendme to start with,
but we wanted to be RFC 1036 compliant.
Upon discovering the tricks
(including mandatory default values for various
.I sys
file fields)
used internally by B News to implement
ihave/sendme,
there was immediate agreement that
.IP (a)
we should document how ihave/sendme works,
and
.IP (b)
we should implement something more obvious
and that would not mandate fixed values for fields
that users might legitimately want to change from their
default values.
.PP
We also see no use for the old unbatched ihave/sendme protocol:
it is grossly wasteful of resources at today's traffic volumes
and offers no clear advantage to sending lists of Message-IDs
in each
.I ihave
or
.I sendme
message.
.PP
The result is that,
in our second implementation,
we have implemented batched ihave/sendme
with
.I batchparms
.Ix batchparms
.Ix files batchparms
specifying details of batching and transport.
One typically needs a single
.I sys
.Ix sys
.Ix files sys
entry
to specify
which articles are to be offered to the other system
via an
.I ihave
message.
.PP
Note that any article requested by a
.I sendme
will be sent;
there is no checking that the requesting site is permitted by its
appropriate
.I sys
entry to receive this article.
Such checking could be added,
at some cost in performance.
For now,
disable ihave/sendme
on systems with `private' newsgroups
(if that isn't an oxymoron).
.PP
See
.I "Setting Up Netnews Feeds Using the Ihave/sendme Protocol"
for gory details including sample
.I sys
files.
.SH
Differences in behaviour
.PP
The
.I checkgroups
.Ix "checkgroups control message"
.Ix "control messages" checkgroups
control message
is non-destructive;
it merely mails its output to
.B NEWSMASTER
(e.g.
.B usenet ).
The distributed
.I checkgroups
script has problems,
which will be fixed some day.
In the mean time,
some people have reported that the latest B News
.I checkgroups
script works fine for them;
you could try it.
.PP
There is an
.I Also-Control:
header recognised,
of which
.I Supersedes:
is a special case.
.SH
Interactions with NNTP
.Ix NNTP
.PP
We had erroneously assumed when writing C News
that the NNTP situation was not too disastrous.
Since we didn't then run NNTP ourselves,
we benignly ignored NNTP.
Only once we started running NNTP did we realise what a
performance
.\" (and other)
disaster it was.
We are still working on improving the situation.
.PP
The
.B CNEWS
ifdef of NNTP
as distributed by Stan Barber
.Ix NNTP "Stan Barber"
makes the situation tolerable
(we supplied the original version of the code inside the ifdef)
if not wonderful.
In particular,
it will happily accept duplicate articles,
only to have
.I relaynews
throw them away.
.\" We have an experimental
.\" .I nntpd
.\" based on NNTP 1.5.8 that we are reasonably happy with,
.\" though lock contention may still be an issue
.\" for a busy site.
Paul Vixie's
.I msgidd
.Ix msgidd
.Ix NNTP msgidd
(and associated nntpd patch)
is strongly recommended for sites
that get more than one incoming NNTP feed;
it eliminates the reception of duplicates.
Sites not running
.I msgidd
or running the reference NNTP implementation without
.B CNEWS
defined
are on their own;
performance of the total news system
is likely to be poor.
.PP
More work is called for.
Several people have simultaneously invented the idea
of a multi-threaded
.I nntpd
handling multiple inbound transfer sessions
and that may be a worthwhile direction to pursue.
(It permits cheap duplicate rejection with little lock contention
and few processes.)
It has the disadvantage of not exploiting parallelism on multiprocessor
machines,
which seem to be what
the biggest news relay sites are becoming.
.SH
dbm & dbz
.Ix dbm
.Ix dbz
.Ix "history index files"
.Ix files "history index"
.PP
There are now several redistributable
.I dbm (3)
clones available.
Before they appeared,
we fixed and enhanced
Jon Zeeff's
.I dbz
library;
it is faster and has smaller files than any
.I dbm
or
.I dbm
clone,
so we recommend using it for news.
Whatever you elect to use,
be sure to link
NNTP and any other software that makes
.I history
file lookups with
the same library that C News uses
(picking up
.I libcnews.a
is usually simplest).
.SH
.LG
.LG
Migration to C News
.Ix "migration to C News"
.NL
.PP
A good first step is to read the documentation in the C News
.I doc
source directory.
You will want to refer to the contents of the
.I man
directory.
If you have trouble formatting any of this documentation,
get the
.I awf
formatter and use it.
.I Awf
.Ix "awf text formatter"
can be had
from your nearby
.I comp.sources.unix
.Ix comp.sources.unix
archive site,
or
by
.I uucp
or
.I ftp
from
.I uunet
.Ix uunet
(\c
.I uunet.uu.net )
as
.I comp.sources.unix/volume23/awf.Z .
For side-by-side comparisons of
B and C News
where this document may have missed something,
one could compare the corresponding sections for B and C News
in
.I "Managing uucp and Usenet" ,
.Ix "Managing uucp and Usenet"
.Ix books "Managing uucp and Usenet"
by Tim O'Reilly and Grace Todino,
O'Reilly & Associates,
1989,
ISBN 0-937175-48-X,
inquiries to
`\c
.B [e-mail] '
or
`\c
.B uunet!ora!nuts ',
or
800-338-NUTS
(in California,
800-533-NUTS),
FAX [phone].
See
.I "Annotated Bibliography on C News"
for a fuller bibliography.
.PP
It is probably safest to create parallel C News trees,
.Ix "test system"
.Ix system test
at least for the equivalent of
.I /usr/lib/news ,
then populate them and rename the B and C trees when you are
satisfied that C News is installed and set up correctly.
The C News installation procedure
(\c
.I build )
.Ix build
will not overwrite existing control files in
.I NEWSCTL ,
so copying your old
.Ix "saving old control files"
.I active ,
.I sys ,
and possibly
.I history
files to
.I NEWSCTL
adapting them as necessary
(see below),
and then installing C News there
normally should get you started.
.PP
One advantage of setting up a parallel tree for C News
is that it is possible,
though
.I build
doesn't know how,
to run all incoming news into both news systems for a day or two
to convince yourself that everything is working right.
If you decide
.I not
to switch,
you can just remove the C News tree.
.Ix "DON'T PANIC!"
In any case,
running both systems simultaneously
avoids the desperate panic of having to
cut everything over at once
and
get it right first time to avoid losing news;
this just should not be necessary any more.
The change is just to ensure that all the commands that
used to invoke
.I rnews
.Ix rnews
(\c
.I inews ,
.Ix inews
.I rnews ,
.I cunbatch
.Ix cunbatch
and probably a few others)
now hand the incoming batch to both news systems.
Something like this should suffice
(and has worked in the past):
.DS
.ft B
# parallel rnews
f=/tmp/rn$$
cat >$f
brnews <$f
crnews <$f
rm $f
.ft
.DE
.PP
.I Sys
.Ix sys
.Ix files sys
.Ix "sys flags"
should only need to be scanned for unsupported flags
(I think
.B S
can just be deleted without ill effect),
and entries
with
.B I
flags rewritten to write
site\c
.B .wehave/togo
and
.I batchparms
.Ix batchparms
.Ix files batchparms
updated to describe the
ihave/sendme
tango for this site.
.I Active
.Ix active
.Ix files active
can optionally be edited to refile groups locally,
to compensate for lack of
.I aliases .
.Ix aliases
.Ix files aliases
C
.I expire
.Ix expire
can read a correct B
.I history
.Ix history
.Ix files history
file,
but B News sometimes produced incorrectly-formatted history files.
To be safe,
and to pick up information that B News didn't store in the history file,
run
.I mkhistory
.Ix mkhistory
to regenerate
.I history
and its index files.
.I Mkhistory
will take quite a while;
it has to open every article in the news system,
which can take hours on some machines.
.\" .PP
.\" Although some of the older documentation warns against
.\" using
.\" .I NEWSCTL/bin/config
.\" as a master configuration file,
.\" we intend to eventually make it so,
.\" and as long as you ensure that you always invoke C News
.\" shell scripts
.\" (which read
.\" .I config
.\" to set environment variables)
.\" and never invoke the C programs directly
.\" (which is generally how things work anyway),
.\" you should be able to get away with treating it as a master
.\" configuration file,
.\" subject to one small caveat:
.\" you need to change
.\" .I inews
.\" to invoke
.\" either
.\" .I newsspool
.\" or
.\" .I rnews ,
.\" and then
.\" arrange to have
.\" .I cron
.\" run
.\" .I newsrun
.\" under the
.\" .I news
.\" userid
.\" (or local equivalent)
.\" fairly frequently
.\" to at least process any local postings.
.PP
The normal installation procedure
is described in
.I "Installing ``C News'' Network News Software"
and really just involves running
.I conf/build ,
.Ix build
answering its (many) questions,
and following its instructions.
(We intend that eventually
.I build
will be run once per site for all time
(or until the hardware or OS change drastically)
and that thereafter
components may be built
using
.I make .)
.Ix make
Do be careful to use the correct userid for each step of installation;
doing the whole thing as
.I root
.Ix userids
will result in incorrect file ownerships.
Two major by-products of
.I build
are
.I libcnews.a
.Ix libcnews.a
in the root of the source subtree
and the directory
.I include .
.PP
There are some differences in configurable options.
All the length and size limits are gone.
Essentially all the B News
.I makefile
options are now queried for by
.I build .
DFLTEXP and HISTEXP
.Ix "B configuration" DFLTEXP
.Ix "B configuration" HISTEXP
are now specified in
.I explist .
.Ix explist
.Ix files explist
Only a trivial newsreader,
a
.I readnews
.Ix readnews
replacement,
is included with C News,
so little of the reader configuration is relevant.
.Ix "B configuration" NOTIFY
NOTIFY is now
.I NEWSMASTER
.Ix NEWSMASTER
and
.I build
queries for it.
.Ix "B configuration" DFTXMIT
.Ix "B configuration" UXMIT
DFTXMIT and UXMIT
are now
.Ix CMDPFX
.Ix CMDSFX
CMDPFX and CMDSFX
in
.I relay/sys.c
with no simple override
(though an override is in the works);
the default command,
in case anyone still uses it,
is
.B "uux - -r -z"
.Ix uux
system\c
.B !rnews .
.Ix "B configuration" MANUALLY
.Ix "B configuration" NONEWGROUPS
.Ix "B configuration" UUPROG
MANUALLY,
NONEWGROUPS
and
UUPROG
are replaced by policy in shell scripts;
edit
.I relay/ctl/*
to taste.
.Ix "B configuration" BATCH
BATCH is gone;
the unbatcher is built into
.Ix unbatcher
.I relaynews .
.Ix "B configuration" OLD
OLD is gone
(\c
.I relaynews
is not a protocol converter).
.Ix "B configuration" DOXREFS
DOXREFS is gone;
.B Xref:
is always generated for cross-posted articles.
.Ix "B configuration" SENDMAIL
.Ix "B configuration" MMDF
SENDMAIL and MMDF
are gone;
we just use
.I mail .
.Ix mail
.Ix "B configuration" DEADTIME
DEADTIME is gone;
locks do not time out.
.PP
This table summarises the disposition of the remaining B News options.
File names in the
`build file'
column are relative to
.I NEWSCTL
and refer to files generated by
.I build .
A `flag' in the
`note'
column indicates that the presence or absence of the file
.I is
the flag.
A `gone' in the
`note'
column indicates that the option has vanished.
If the
`build file'
column is empty,
the option has just been absorbed into
.I build .
.Ix "B configuration" "summary table"
.TS
box, center;
c c c
l l c .
B option    build file    note
_
SPOOLNEWS    rnews.newsrun    flag
INTERNET    replyusepath    flag
MYDOMAIN    mailname
MYORG    organization
UUNAME    whoami
_
CHEAP        gone
NICENESS        gone
FASCIST        gone
ORGDISTRIB        gone
MULTICAST        gone
_
UNAME
GHNAME
BSD4_2
BSD4_1C
LOCKF
HIDDENNET
SMALL_ADDRESS_SPACE
.TE
.PP
If you compile and install the software as two steps,
it is simple,
though time-consuming,
to run regression tests
.Ix regression tests
for the major subsystems:
.B cd
into a source directory
(e.g.
.I expire ,
.I batch ,
.I relay )
and type
.B "make r".
If you get no complaints,
the software is believed (after testing)
to work correctly on your machine.
.PP
.Ix relaynews tuning
.Ix tuning relaynews
Sites with a lot of outgoing news feeds
(over 60, say),
should be aware that batch file writing will probably
dominate
.I relaynews 's
elapsed time.
We hope to fix this.
.\" could add a checklist here.
.PP
After installation,
errors will generally be reported by mail
(to
.I NEWSMASTER
[typically
.I usenet ]).
To watch the progress of incoming news,
tail
.I NEWSCTL/log
and
.I NEWSCTL/errlog .
.I errlog
should be empty on a smoothly-running system.