dcae809e0d
a local branch. Text from an email from jdp@ Reported by: simon
485 lines
18 KiB
Groff
485 lines
18 KiB
Groff
.\" Copyright (c) 1998, Matthew Dillon. Terms and conditions are those of
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.\" the BSD Copyright as specified in the file "/usr/src/COPYRIGHT" in
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.\" the FreeBSD source tree.
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.\"
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.\" $FreeBSD$
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.\"
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.Dd December 21, 2002
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.Dt DEVELOPMENT 7
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.Os
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.Sh NAME
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.Nm development
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.Nd introduction to development with the FreeBSD codebase
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.Sh DESCRIPTION
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This manual page describes how an ordinary sysop,
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.Ux admin, or developer
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can, without any special permission, obtain, maintain, and modify the
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.Fx
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codebase as well as how to maintaining a master build which can
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then be exported to other machines in your network.
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This manual page
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is targeted to system operators, programmers, and developers.
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.Pp
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Please note that what is being described here is based on a complete
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FreeBSD environment, not just the FreeBSD kernel.
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The methods described
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here are as applicable to production installations as it is to development
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environments.
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You need a good 12-17GB of disk space on one machine to make this work
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conveniently.
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.Sh SETTING UP THE ENVIRONMENT ON THE MASTER SERVER
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Your master server should always run a stable, production version of the
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.Fx
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operating system. This does not prevent you from doing -CURRENT
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builds or development. The last thing you want to do is to run an
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unstable environment on your master server which could lead to a situation
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where you lose the environment and/or cannot recover from a mistake.
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.Pp
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Create a huge partition called /FreeBSD.
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8-12GB is recommended.
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This partition will contain nearly all the development environment,
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including the CVS tree, broken-out source, and possibly even object files.
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You are going to export this partition to your other machines via a
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READ-ONLY NFS export so do not mix it with other more security-sensitive
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partitions.
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.Pp
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You have to make a choice in regards to
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.Pa /usr/obj .
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You can put
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.Pa /usr/obj
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in
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.Pa /FreeBSD
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or you can make
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.Pa /usr/obj
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its own partition.
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I recommend making it a separate partition for several reasons. First,
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as a safety measure since this partition is written to a great deal.
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Second, because you typically do not have to back it up.
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Third, because it makes it far easier to mix and match the development
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environments which are described later in this document.
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I recommend a
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.Pa /usr/obj
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partition of at least 5GB.
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.Pp
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On the master server, use cvsup to automatically pull down and maintain
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the
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.Fx
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CVS archive once a day. The first pull will take a long time,
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it is several gigabytes, but once you have it the daily syncs will be quite
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small.
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.Bd -literal -offset 4n
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mkdir /FreeBSD/FreeBSD-CVS
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rm -rf /home/ncvs
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ln -s /FreeBSD/FreeBSD-CVS /home/ncvs
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.Ed
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.Pp
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The cron job should look something like this (please randomize the time of
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day!).
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Note that you can use the cvsup file example directly from
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/usr/share/examples without modification by supplying appropriate arguments
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to cvsup.
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.Bd -literal -offset 4n
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33 6 * * * /usr/local/bin/cvsup -g -r 20 -L 2 -h cvsup.freebsd.org /usr/share/examples/cvsup/cvs-supfile
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.Ed
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.Pp
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Run the cvsup manually the first time to pull down the archive. It could take
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all day depending on how fast your connection is!
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You will run all cvsup and cvs operations as root and you need to set
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up a ~/.cvsrc (/root/.cvsrc) file, as shown below, for proper cvs operation.
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Using ~/.cvsrc to specify cvs defaults is an excellent way
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to "file and forget", but you should never forget that you put them in there.
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.Bd -literal -offset 4n
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# cvs -q
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diff -u
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update -Pd
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checkout -P
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.Ed
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.Pp
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Now use cvs to checkout a -STABLE source tree and a -CURRENT source tree,
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as well as ports and docs, to create your initial source environment.
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Keeping the broken-out source and ports in /FreeBSD allows you to export
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it to other machines via read-only NFS.
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This also means you only need to edit/maintain files in one place and all
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your clients automatically pick up the changes.
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.Bd -literal -offset 4n
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mkdir /FreeBSD/FreeBSD-4.x
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mkdir /FreeBSD/FreeBSD-current
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cd /FreeBSD/FreeBSD-4.x
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cvs -d /home/ncvs checkout -rRELENG_4 src
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cd /FreeBSD/FreeBSD-current
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cvs -d /home/ncvs checkout src
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cvs -d /home/ncvs checkout ports
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cvs -d /home/ncvs checkout doc
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.Ed
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.Pp
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Now create a softlink for /usr/src and /usr/src2.
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On the main server I always point /usr/src at -STABLE and /usr/src2 at
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-CURRENT. On client machines I usually do not have a /usr/src2 and I make
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/usr/src point at whatever version of FreeBSD the client box is intended to
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run.
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.Bd -literal -offset 4n
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cd /usr
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rm -rf src src2
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ln -s /FreeBSD/FreeBSD-4.x/src src (could be -CURRENT on a client)
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ln -s /FreeBSD/FreeBSD-current/src src2 (MASTER SERVER ONLY)
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.Ed
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.Pp
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Now you have to make a choice for /usr/obj.
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Well, hopefully you made it already and chose the partition method. If you
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chose poorly you probably intend to put it in /FreeBSD and, if so, this is
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what you want to do:
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.Bd -literal -offset 4n
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(ONLY IF YOU MADE A POOR CHOICE AND PUT /usr/obj in /FreeBSD!)
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mkdir /FreeBSD/obj
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cd /usr
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rm -rf obj
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ln -s /FreeBSD/obj obj
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.Ed
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.Pp
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Alternatively you may chose simply to leave /usr/obj in /usr. If your
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/usr is large enough this will work, but I do not recommend it for
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safety reasons (/usr/obj is constantly being modified, /usr is not).
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.Pp
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Note that exporting /usr/obj via read-only NFS to your other boxes will
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allow you to build on your main server and install from your other boxes.
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If you also want to do builds on some or all of the clients you can simply
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have /usr/obj be a local directory on those clients.
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You should never export /usr/obj read-write, it will lead to all sorts of
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problems and issues down the line and presents a security problem as well.
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It is far easier to do builds on the master server and then only do installs
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on the clients.
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.Pp
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I usually maintain my ports tree via CVS.
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It is sitting right there in the master CVS archive and I've even told you
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to check it out (see above).
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With some fancy softlinks you can make the ports tree available both on your
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master server and on all of your other machines.
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Note that the ports tree exists only on the HEAD cvs branch, so its always
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-CURRENT even on a -STABLE box. This is what you do:
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.Bd -literal -offset 4n
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(THESE COMMANDS ON THE MASTER SERVER AND ON ALL CLIENTS)
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cd /usr
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rm -rf ports
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ln -s /FreeBSD/FreeBSD-current/ports ports
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cd /usr/ports (this pushes into the softlink)
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rm -rf distfiles (ON MASTER SERVER ONLY)
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ln -s /usr/ports.distfiles distfiles (ON MASTER SERVER ONLY)
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mkdir /usr/ports.distfiles
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mkdir /usr/ports.workdir
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.Ed
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.Pp
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Since /usr/ports is softlinked into what will be read-only on all of your
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clients, you have to tell the ports system to use a different working
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directory to hold ports builds.
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You want to add a line to your /etc/make.conf file on the master server
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and on all your clients:
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.Bd -literal -offset 4n
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WRKDIRPREFIX=/usr/ports.workdir
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.Ed
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.Pp
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You should try to make the directory you use for the ports working directory
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as well as the directory used to hold distfiles consistent across all of your
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machines.
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If there isn't enough room in /usr/ports.distfiles and /usr/ports.workdir I
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usually make those softlinks (since this is on /usr these are per-machine) to
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where the distfiles and working space really are.
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.Sh EXPORTING VIA NFS FROM THE MASTER SERVER
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The master server needs to export /FreeBSD and /usr/obj via NFS so all the
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rest of your machines can get at them.
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I strongly recommend using a read-only export for both security and safety.
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The environment I am describing in this manual page is designed primarily
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around read-only NFS exports.
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Your exports file on the master server should contain the following lines:
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.Bd -literal -offset 4n
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/FreeBSD -ro -alldirs -maproot=root: -network YOURLAN -mask YOURLANMASK
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/usr/obj -ro -alldirs -maproot=root: -network YOURLAN -mask YOURLANMASK
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.Ed
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.Pp
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Of course, NFS server operations must also be configured on that machine.
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This is typically done via your /etc/rc.conf:
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.Bd -literal -offset 4n
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nfs_server_enable="YES"
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nfs_server_flags="-u -t -n 4"
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.Ed
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.Sh THE CLIENT ENVIRONMENT
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All of your client machines can import the development/build environment
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directory simply by NFS mounting /FreeBSD and /usr/obj from the master
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server.
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A typical /etc/fstab entry on your client machines will be something like this:
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.Bd -literal -offset 4n
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masterserver:/FreeBSD /FreeBSD nfs ro,bg 0 0
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masterserver:/usr/obj /usr/obj nfs ro,bg 0 0
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.Ed
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.Pp
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And, of course, you should configure the client for NFS client operations
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via /etc/rc.conf.
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In particular, this will turn on nfsiod which will improve client-side NFS
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performance:
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.Bd -literal -offset 4n
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nfs_client_enable="YES"
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.Ed
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.Pp
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Each client should create softlinks for /usr/ports and /usr/src that point
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into the NFS-mounted environment.
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If a particular client is running -CURRENT, /usr/src
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should be a softlink to /FreeBSD/FreeBSD-current/src.
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If it is running -STABLE, /usr/src should be a softlink to
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/FreeBSD/FreeBSD-4.x/src. I do not usually create a /usr/src2 softlink on
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clients, that is used as a convenient shortcut when working on the source
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code on the master server only and could create massive confusion (of the
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human variety) on a client.
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.Bd -literal -offset 4n
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(ON EACH CLIENT)
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cd /usr
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rm -rf ports src
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ln -s /FreeBSD/FreeBSD-current/ports ports
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ln -s /FreeBSD/FreeBSD-XXX/src src
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.Ed
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.Pp
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Don't forget to create the working directories so you can build ports, as
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previously described.
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If these are not good locations, make them softlinks to the correct location.
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Remember that /usr/ports/distfiles is exported by
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the master server and is therefore going to point to the same place
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(typically /usr/ports.distfiles) on every machine.
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.Bd -literal -offset 4n
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mkdir /usr/ports.distfiles
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mkdir /usr/ports.workdir
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.Ed
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.Sh BUILDING KERNELS
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Here is how you build a -STABLE kernel (on your main development box).
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If you want to create a custom kernel, cp GENERIC to YOURKERNEL and then
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edit it before configuring and building.
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The kernel configuration file lives in /usr/src/sys/i386/conf/KERNELNAME.
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.Bd -literal -offset 4n
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cd /usr/src
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make buildkernel KERNCONF=KERNELNAME
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.Ed
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.Pp
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.Sy WARNING!
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If you are familiar with the old config/cd/make method of building
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a -STABLE kernel, note that the config method will put the build
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environment in /usr/src/sys/compile/KERNELNAME instead of in /usr/obj.
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.Pp
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Building a -CURRENT kernel
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.Bd -literal -offset 4n
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cd /usr/src2 (on the master server)
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make buildkernel KERNCONF=KERNELNAME
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.Ed
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.Sh INSTALLING KERNELS
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Installing a -STABLE kernel (typically done on a client.
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Only do this on your main development server if you want to install a new
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kernel for your main development server):
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.Bd -literal -offset 4n
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cd /usr/src
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make installkernel KERNCONF=KERNELNAME
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.Ed
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.Pp
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If you are using the older config/cd/make build mechanism for stable, you
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would install using:
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.Bd -literal -offset 4n
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cd /usr/src/sys/compile/KERNELNAME
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make install
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.Ed
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.Pp
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Installing a -CURRENT kernel (typically done only on a client)
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.Bd -literal -offset 4n
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(remember /usr/src is pointing to the client's specific environment)
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cd /usr/src
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make installkernel KERNCONF=KERNELNAME
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.Ed
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.Pp
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.Sh BUILDING THE WORLD
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This environment is designed such that you do all builds on the master server,
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and then install from each client.
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You can do builds on a client only if /usr/obj is local to that client.
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Building the world is easy:
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.Bd -literal -offset 4n
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cd /usr/src
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make buildworld
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.Ed
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.Pp
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If you are on the master server you are running in a -STABLE environment, but
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that does not prevent you from building the -CURRENT world.
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Just cd into the appropriate source directory and you are set. Do not
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accidentally install it on your master server though!
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.Bd -literal -offset 4n
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cd /usr/src2
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make buildworld
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.Ed
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.Sh INSTALLING THE WORLD
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You can build on your main development server and install on clients.
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The main development server must export /FreeBSD and /usr/obj via
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read-only NFS to the clients.
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.Pp
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.Em NOTE!!!
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If /usr/obj is a softlink on the master server, it must also be the EXACT
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SAME softlink on each client.
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If /usr/obj is a directory in /usr or a mount point on the master server,
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then it must be (interchangeably) a directory in /usr or a mount point on
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each client.
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This is because the
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absolute paths are expected to be the same when building the world as when
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installing it, and you generally build it on your main development box
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and install it from a client.
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If you do not setup /usr/obj properly you will not be able to build on
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machine and install on another.
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.Bd -literal -offset 4n
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(ON THE CLIENT)
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(remember /usr/src is pointing to the client's specific environment)
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cd /usr/src
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make installworld
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.Ed
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.Pp
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.Sy WARNING!
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If builds work on the master server but installs do not work from the
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clients, for example you try to install and the client complains that
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the install tried to write into the read-only /usr/obj, then it is likely
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that the /etc/make.conf file on the client does not match the one on the
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master server closely enough and the install is trying to install something
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that was not built.
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.Sh DOING DEVELOPMENT ON A CLIENT (NOT JUST INSTALLING)
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Developers often want to run buildkernel's or buildworld's on client
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boxes simply to life-test the box.
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You do this in the same manner that you buildkernel and buildworld on your
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master server.
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All you have to do is make sure that /usr/obj is pointing to local storage.
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If you followed my advise and made /usr/obj its own partition on the master
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server,
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then it is typically going to be an NFS mount on the client.
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Simply unmounting /usr/obj will leave you with a /usr/obj that is a
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subdirectory in /usr which is typically local to the client.
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You can then do builds to your heart's content!
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.Sh MAINTAINING A LOCAL BRANCH
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I have described how to maintain two versions of the source tree, a stable
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version in /FreeBSD/FreeBSD-4.x and a current version
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in /FreeBSD/FreeBSD-current.
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There is absolutely nothing preventing you
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from breaking out other versions of the source tree
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into /FreeBSD/XXX.
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In fact, my /FreeBSD partition also contains
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.Ox ,
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.Nx ,
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and various flavors of Linux.
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You may not necessarily be able to build non-FreeBSD operating systems on
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your master server, but being able
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to collect and manage source distributions from a central server is a very
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useful thing to be able to do and you can certainly export to machines
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which can build those other operating systems.
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.Pp
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Many developers choose to maintain a local branch of
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.Fx
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to test patches or build a custom distribution.
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This can be done with CVS or another source code management system
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(SubVersion, Perforce, BitKeeper) with its own repository.
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Since the main
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.Fx
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tree is based on CVS, the former is convenient.
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.Pp
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First, you need to modify your cvsup environment to avoid it modifying
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the local changes you have committed to the repository.
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It is important to remove the "delete" keyword from your supfile and to
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add the CVSROOT subdirectory to your refuse file.
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For more information, see
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.Xr cvsup 1 .
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.Pp
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The
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.Fx
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version of CVS examines a custom environmental variable,
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CVS_LOCAL_BRANCH_NUM, which specifies an integer to use when doing a cvs
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tag/rtag.
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Set this number to something high (say 1000) to avoid colliding
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with potential future branches of the main repository. For example,
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branching a file with version 1.4 produces 1.4.1000.
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Future commits to this branch will produce revisions 1.4.1000.1,
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1.4.1000.2, etc.
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.Pp
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To fork your local branch, do:
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.Bd -literal -offset 4n
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cvs rtag -r RELENG_4 -b LOCAL_RELENG_4 src
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.Ed
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.Pp
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After this, you can check out a copy from your local repository using the
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new tag and begin making changes and committing them.
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For more information on using cvs, see
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.Xr cvs 1 .
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.Pp
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.Sy WARNING!
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The cvsup utility may blow away changes made on a local branch in
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some situations.
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This has been reported to occur when the master CVS repository is
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directly manipulated or an RCS file is changed.
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At this point, cvsup notices that the client and server have entirely
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different RCS files, so it does a full replace instead of trying to
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send just deltas.
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Ideally this situation should never arise, but in the real world it
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happens all the time.
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.Pp
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While this is the only scenario where the problem should crop up,
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there have been some suspicious-sounding reports of
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CVS_LOCAL_BRANCH_NUM lossage that can't be explained by this alone.
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Bottom line is, if you value your local branch then you
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should back it up before every update.
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.Sh UPDATING VIA CVS
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The advantage of using cvsup to maintain an updated copy of the CVS
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repository instead of using it to maintain source trees directly is that you
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can then pick and choose when you bring your source tree (or pieces of your
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source tree) up to date.
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By using a cron job to maintain an updated CVS repository, you can update
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your source tree at any time without any network cost as follows:
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.Bd -literal -offset 4n
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(on the main development server)
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cd /usr/src
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cvs -d /home/ncvs update
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cd /usr/src2
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cvs -d /home/ncvs update
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cd /usr/ports
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cvs -d /home/ncvs update
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.Ed
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.Pp
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It is that simple, and since you are exporting the whole lot to your
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clients, your clients have immediately visibility into the updated
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source.
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This is a good time to also remind you that most of the cvs operations
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you do will be done as root, and that certain options are
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required for CVS to operate properly on the
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.Fx
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repository. For example,
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.Fl Pd
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is necessary when running "cvs update".
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These options are typically placed in your ~/.cvsrc (as already described)
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|
so you do not have to respecify them every time you run a CVS command.
|
|
Maintaining the CVS repository also gives you far more flexibility
|
|
in regards to breaking out multiple versions of the source tree.
|
|
It is a good idea to give your /FreeBSD partition a lot of space (I recommend
|
|
8-12GB) precisely for that reason.
|
|
If you can make it 15GB I would do it.
|
|
.Pp
|
|
I generally do not cvs update via a cron job.
|
|
This is because I generally want the source to not change out from under me
|
|
when I am developing code.
|
|
Instead I manually update the source every so often... when I feel it is
|
|
a good time.
|
|
My recommendation is to only keep the cvs repository synchronized via cron.
|
|
.Sh SEE ALSO
|
|
.Xr crontab 1 ,
|
|
.Xr crontab 5 ,
|
|
.Xr build 7 ,
|
|
.Xr firewall 7 ,
|
|
.Xr release 7 ,
|
|
.Xr tuning 7 ,
|
|
.Xr diskless 8
|
|
.Sh HISTORY
|
|
The
|
|
.Nm
|
|
manual page was originally written by
|
|
.An Matthew Dillon Aq dillon@FreeBSD.org
|
|
and first appeared
|
|
in
|
|
.Fx 5.0 ,
|
|
December 2002.
|