man/man1/dpb.1

.\"	$OpenBSD: dpb.1,v 1.34 2023/06/17 19:35:54 espie Exp $
.\"
.\" Copyright (c) 2010-2013 Marc Espie <espie@openbsd.org>
.\"
.\" Permission to use, copy, modify, and distribute this software for any
.\" purpose with or without fee is hereby granted, provided that the above
.\" copyright notice and this permission notice appear in all copies.
.\"
.\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
.\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
.\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
.\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
.\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
.\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
.\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
.\"
.Dd $Mdocdate: June 17 2023 $
.Dt DPB 1
.Os
.Sh NAME
.Nm dpb
.Nd distributed ports builder
.Sh SYNOPSIS
.Nm dpb
.Op Fl acemqRrsUuvx
.Op Fl A Ar arch
.Op Fl B Ar chroot
.Op Fl b Ar logfile
.Op Fl C Ar pathlist
.Op Fl D Ar PARAM Ns = Ns Ar value
.Op Fl F Ar m
.Op Fl f Ar m
.Op Fl h Ar hosts
.Op Fl I Ar pathlist
.Op Fl J Ar p
.Op Fl j Ar n
.Op Fl L Ar logdir
.Op Fl l Ar lockdir
.Op Fl M Ar threshold
.Op Fl P Ar pathlist
.Op Fl p Ar parallel
.Op Fl S Ar logfile
.Op Fl X Ar pathlist
.Op Ar pathlist ...
.Sh DESCRIPTION
.Nm
is used to build ports on a cluster of machines, or on a single machine
with several cores.
.Nm
walks the ports tree to figure out dependencies, and starts building ports
as soon as it can.
.Pp
.Nm
will run with sensible defaults if used without options.
Note, however, that it will produce logs, lock files, packages, and package
installations.
.Pp
If run as non-root,
.Nm
will warn.
The preferred way is to run it as root (and preferably under a chroot, see
.Xr bulk 8
and
.Xr proot 1
for example setups).
.Nm
will then change its identity to different users as needed.
See
.Sx THE SECURITY MODEL OF DPB
for details.
.Pp
.Nm
can be restricted to a subset of the tree by giving it
.Ar pathlist ...
to build as parameters.
.Pp
A
.Ar pathlist
is either a
.Xr pkgpath 7
to build, or a filename that contains pkgpaths (one per line).
.Ar pathlist
parameters can also take the form
.Li filename*scale
in order to multiply the weights of all
.Xr pkgpath 7
in a file by a given
.Ar scale ,
or
.Li pkgpath=value ,
in order to set the weight of a given
.Xr pkgpath 7
to a specific value.
.Pp
.Nm
supports
.Sq hot-fixes :
if a particular port errors out, it is possible to fix the problem, remove
the corresponding lockfile, and
.Nm
will pick it up without needing to be stopped and restarted.
.Pp
In order to build on a cluster, the ports tree itself should be identical
on each machine (shared through NFS or copied at start).
.Pp
Some directories must be shared:
.Ev PACKAGE_REPOSITORY ,
.Ev DISTDIR ,
and
.Ev PLIST_REPOSITORY .
The
.Ev WRKOBJDIR
and
.Ev LOCKDIR
should be local to each machine, and on a high-speed partition.
.Pp
Also note that
.Nm Ns 's
logs and locks are managed by the main
.Nm
process, which runs locally, and hence those directories do not need to
be shared on the cluster.
.Pp
Some log files ("rolling logs") are kept from one run to the run and
stored under
.Pa ${DISTDIR}/build-stats .
On each run, the most recent entries for each pkgpath
.Po
see
.Ar STATS_USED
.Pc
are used to figure out in which order things should be built.
Meanwhile, some more entries are kept around
.Po
see
.Ar STATS_BACKLOG
.Pc
for potential data analysis over longer periods.
.Pp
Option
.Fl h Ar file
is used to specify hosts to use, where
.Ar file
may contain lots of information,
but can be as simple as a list of hosts to use, one host per line
(however, it is recommended to also include a
.Ar STARTUP
script).
.Pp
Most filenames will go through some control sequence expansions.
For instance, the default logdir location can be specified as
.Pa %p/logs/%a .
The following sequences are recognized:
.Bl -tag -offset aaaa -width %aa
.It Cm %a
architecture being used.
.It Cm %d
date at start of
.Nm ,
GMtime, formatted as yyyy-mm-dd@hh:mm:ss.
.It Cm %f
fetch distfiles location (DISTDIR).
.It Cm %h
short hostname running
.Nm .
.It Cm %L
logdir location.
.It Cm %p
portsdir location.
.It Cm %t
timestamp (number of seconds since January 1 1970) at start of
.Nm .
.It Cm %$
Pid of the main
.Nm
process .
.El
.Pp
Options are as follows:
.Bl -tag -width pkgpathlong
.It Fl A Ar arch
Build packages for given architecture, selecting relevant hosts from the
cluster.
By default, the current host's architecture will be used.
.It Fl a
Walk the whole tree and builds all packages (default if no
.Ar pathlist
is given).
.It Fl B Ar chroot
chroot to
.Ar chroot
before building.
See
.Xr proot 1
for preparing such an environment.
.It Fl b Ar logfile
Explicitly prime the heuristics module with a previous build log,
so that packages that take a long time to build will happen earlier.
The rolling log file under
.Pa %f/build-stats/%a
is automatically used.
.It Fl C Ar pathlist
Don't clean port working directories after build.
Only use simple
.Xr pkgpath 7
in the list,
as this does not take subpackages and flavors into account.
.It Fl c
Clean port working directory and log before each build.
.It Fl D Ar PARAM Ns = Ns Ar value
Set defined parameter to value.
Known parameters are as follows:
.Bl -tag -width DISP
.It Ar ALWAYS_CLEAN
Set to 1 if
.Nm
should clean work directories even if the port errored out.
.It Ar BUILD_USER
Default value for
.Ar build_user
if you want to specify it on the command line, and want to ensure even
the small "discover PORTSDIR" activity at the beginning of
.Nm
is not run as root.
.It Ar COLOR
Set to 1 to have the normal display in color.
.It Ar CONNECTION_TIMEOUT
Connection timeout for ssh.
Defaults to 10 seconds (but ssh will retry 3 times).
.It Ar CONTROL
Let
.Nm
create a unix socket of the given name for external control.
Defaults to
.Sq %L/control-%h-%$ .
If no socket is wanted, explicitly set
.Ar CONTROL
to empty.
.It Ar DISPLAY_TIMEOUT
Display timeout (in seconds) while waiting for jobs to finish, so that the
display is updated even if jobs didn't finish.
Defaults to 10 seconds.
.It Ar DONT_BUILD_ONCE
By default,
.Nm
will use the
.Ev BUILD_ONCE
optimization
.Po
see
.Xr bsd.port.mk 5
.Pc
if run with
.Fl a :
pseudo-flavors that disable subpackages and are not necessary for bootstrap
will be disabled, so that the same port is built once, as far as possible.
This flag disables that optimization, which might be desirable if you want
to build a small subset of packages which would pull in the kitchen sink
otherwise.
.It Ar DONT_CLEAN_LOCKS
By default,
.Nm
will clean old locks from dpb running on the same host that no longer exist,
provided they didn't end in error.
This is usually the right thing to do after a crash, or after killing dpb
abruptly.
Sometimes, one may want manual control over which locks to remove.
.It Ar FETCH_JOBS
Alternate way to specify the number of fetch jobs.
.It Ar FETCH_TIMEOUT
Timeout (in seconds) after which fetches that don't show
any progress will be killed.
This can be instead set in
.Ar DEFAULT
or
.Ar localhost
as the
.Sq fetch_timeout
property.
.It Ar FETCH_CMD
Override for the default
.Ar FETCH_CMD
coming from ports.
This might be useful because fetching isn't chroot'd
and is run as ${FETCH_USER}.
.It Ar FETCH_USER
User for all fetch activities if possible
.Po defaults to
.Ar _pfetch
.Pc .
.It Ar FTP_ONLY
Don't fetch distfiles/don't build packages that are not allowed for ftp.
.It Ar HISTORY_ONLY
Don't fetch or build anything.
Only run
.Nm
to figure out old distfiles and update
.Pa %f/history .
.It Ar LISTING_EXTRA
Alternate way to specify
.Fl e .
.It Ar LOCKDIR
Alternate way to specify the locking directory.
.It Ar LOGDIR
Alternate way to specify the logging directory.
.It Ar LOG_USER
User
for all log files if possible
.Po defaults to
.Ar build_user
.Pc .
.It Ar MIRROR
Applicable to fetch modes.
If 0, will only fetch normal
.Ev DISTFILES
.Po
default for
.Nm Fl f
.Pc .
If 1, will also fetch extra
.Ev SUPDISTFILES
.Po
default for
.Nm Fl F
.Pc .
.It Ar NEVER_CLEAN
If 1,
.Nm
will never clean any work directory after build.
.It Ar NO_BUILD_STATS
Disable reading/saving of default build stats under
.Pa ${DISTDIR}/build-stats/${ARCH} .
.It Ar NO_CHECKSUM
Do not run
.Ar checksum
again for files already fetched.
.It Ar NO_CURSOR
Make the terminal cursor invisible if possible.
Avoids flickering on slow graphics cards.
.It Ar NO_HISTORY
Do not update the distfiles history.
For instance, if
.Nm
is run a second time after a problem during the first run.
.It Ar NO_QUICK_SCAN
Disable the quick scan default heuristic,
where full bulks will start by scanning the most prominent ports
in former builds.
.It Ar PORT_USER
User that can write to the ports tree.
Not really used for anything yet.
.It Ar RECORD
Define a file which will save all terminal output.
Mostly useful for presentations, as a way to save
.Nm dpb
output and replay it later at a faster rate.
Defaults to
.Pa %L/term-report.log ,
can be set to nothing to disable.
.It Ar STARTUP
Define a start-up script on the command-line, override any host file contents.
.It Ar STATS_BACKLOG
Max number of stats (per individual pkgpath) to save in the rolling log file
.Po
defaults to 25
.Pc .
.It Ar STATS_USED
Clamp number of stats (per individual pkgpath) used for computing build
order
.Po
defaults to 10
.Pc .
.It Ar STUCK_TIMEOUT
Timeout (in seconds * speed factor) after which tasks that don't show
any progress will be killed.
This can be instead set on a per-core basis as the
.Sq stuck
property.
Note that this will always be divided by the core's speed factor.
.It Ar SYSLOG
Make
.Nm
call
.Xr syslog 3
on every task start/end while creating packages.
This does produce lots of messages, it is intended to route the logging
on another machine, while tracking down panics and other hangs.
.It Ar WANTSIZE
Alternate way to specify
.Fl s .
.El
.It Fl e
The listing job is extra and won't be given back to the pool when it's
finished.
.It Fl F Ar m
Fetch-only mode, for mirroring hosts.
Do not build any package but fetch everything, disregarding
.Ev BROKEN
and
.Ev ONLY_FOR_ARCHS
information.
Create
.Ar m
localhost jobs for fetching files.
.It Fl f Ar m
Create
.Ar m
jobs for fetching files.
Those are separate from the build jobs, since they don't consume cpu, and they
run on the localhost.
Defaults to 2.
Can be set to 0 to bypass fetching jobs entirely,
and reduce
.Nm
memory footprint by a lot.
.It Fl h Ar hosts
File with hosts to use for building.
One host per line, plus properties, such as:
.Bd -literal -offset indent
espie@aeryn jobs=4 arch=i386
.Ed
.Pp
Lines starting with a known variable name such as
.Bd -literal -offset indent
STARTUP=path
.Ed
or
.Bd -literal -offset indent
FETCH_JOBS=5
.Ed
can also be set inside a configuration file, to reduce the number of
options you must pass on the command line.
.Pp
The special hostname
.Ar DEFAULT
can be used to preset defaults.
It should be used at the start of the file.
.Pp
Use
.Ar localhost
to specify the local machine.
.Nm
will special-case it and not use
.Xr ssh 1
to connect.
.Pp
Properties are as follows:
.Bl -tag -width memory=150
.It always_clean=n
Set to 0 or 1 on per-host basis.
See
.Ar ALWAYS_CLEAN
parameter.
.It arch=value
Architecture of the concerned host.
(there should be a startup task to check consistency, but
currently this has to be set manually on heterogeneous networks.)
.It build_user=user
Use
.Ar user
for non root jobs if possible (defaults to
.Xr whoami 1
value).
.It chroot=dir
Chroot to
.Ar dir
before building.
.It fetch_timeout=s
Timeout (in seconds) after which fetches that don't show
any progress will be killed.
Only makes sense for
.Ar DEFAULT
or
.Ar localhost .
.It jobs=n
Number of jobs to run on that host, defaults to hw.ncpuonline.
.It junk=n
Junk unused packages each n steps.
See
.Fl J
option.
.It memory=thr
Build everything below that wrkdir threshold with
.Ev USE_MFS Ns = Ns Sq Yes ,
assuming the ports tree has been configured so that
.Ev WRKOBJDIR_MFS
points to a memory filesystem.
.Ar thr
is the sum, in KBytes, of ports that will be allowed to build in memory.
.Nm
understands suffixes, such as
.Fl M Ar 2G
or
.Fl M Ar 500M .
.Pp
Note that you should always allow for some margin, as
.Nm
makes its decision based on the size information collected during previous
builds, so in cases of significant updates, the work directory size will
usually grow.
.It nochecksum=0/1
Defaults to 1.
During the junk stage, run
.Xr pkg_delete 1
with the
.Fl q
(no checksum) option.
.It parallel=p
Run big ports on several cores.
See
.Fl p
option.
.It parallel2=p
Run largest ports on many cores.
Defaults to the same value as the parallel option, but can be increased for,
say, chromium.
.It repair=0/1
Defaults to 1.
Run
.Xr pkg_add 1
with the repair option.
This is useful on some bulk machines which tend to crash a lot, leaving
.Pa /var/db/pkg
in a weird state.
.It sf=n
Speed factor.
An estimate of that machine's speed with that number of jobs
compared to other machines in the same network.
Works better with small values, in the range of 1..50.
The machine (or machines) with the highest speed factor will
get access to all jobs, whereas other machines will be clamped
to stuff which does not take too long.
Requires previous build information to be effective.
Defaults to 1.
.It small=s
Small threshold (in seconds * sf):
ports known to build under that duration are deemed to be small, so
.Nm
won't bother calling fine-grained steps for patch/configure/fake.
It will go straight to build and package instead.
Defaults to 120 seconds.
.It squiggles=n
Number of squiggles on this host (see
.Sx THE SQUIGGLE HEURISTICS
below).
Defaults to 1 squiggle for hosts with 4 jobs or more, 0.7 for hosts with more than 1 job,
0 for single job hosts.
.It stuck=s
Stuck timeout (in seconds * sf) after which tasks which show no progress
will get killed.
.It timeout=s
Defines a specific connection timeout for ssh to that host.
.El
.Pp
There are no fine-grained options to control
.Xr ssh 1
options, as those can be specified through virtual host declarations in
.Xr ssh_config 5 .
.It Fl I Ar pathlist
List of
.Xr pkgpath 7
to install, on the local box.
This will also add them to the list of things to build.
.It Fl J Ar p
Override value for the
.Dq junk
property.
Delete unneeded installed packages during the build.
Each
.Ar prepare
stage is followed by a
.Ar show-prepare-results
stage.
After every
.Ar p
new dependencies, it will be followed by a
.Ar junk
stage which uses
.Xr pkg_delete 1
with the
.Fl aXI
options to delete automatically installed packages that are currently
not needed.
.Pp
.Nm
keeps track of list of dependencies on a given host, by storing each
dependency list in the lockfile corresponding to the package being built.
.Pp
To avoid a race condition between the
.Ar depends
and
.Ar junk
stages,
.Nm
allows only one job on a given host to be in the
.Ar depends
\&...
.Ar junk
stages at one time, by using a per-host lock.
.Pp
Defaults to
.Ar 150 .
Can be disabled by setting to
.Ar 0 .
.Pp
Some ports, most notably cmake-based, have an annoying dependency handling
bug: they compute their makefile dependencies based on all include files
present, not just the ones that are actually enabled.
Those ports' build may be broken by a
.Ar junk
phase that removes some unused includes that were added as makefile
prerequisites.
Those ports should be annotated with
DPB_PROPERTIES = nojunk
until that bug is fixed:
while a port with the
.Sq nojunk
property is building,
.Ar junk
will be postponed.
.Pp
Those ports will be marked with a
.Sq \&!
in the display, to make it more obvious why junk seems to be ineffective.
.Pp
Note that the
.Sq nojunk
property is still active for ports in error, in the belief that trivial fixes
can be made that will allow the port build to finish.
.It Fl j Ar n
Number of jobs to run on a single host (defaults to hw.ncpuonline).
.It Fl L Ar logdir
Choose a log directory.
.Po
Defaults to
.Pa %p/logs/%a
.Pc .
.It Fl l Ar lockdir
Choose a lock directory.
.Po
Defaults to
.Pa %L/locks
.Pc .
Override to keep local, as locks don't really like NFS.
.It Fl M Ar threshold
Build ports below the memory threshold under a memory
filesystem, as configured through
.Ev WRKOBJDIR_MFS
.Po
see
.Xr bsd.port.mk 5
.Pc .
.Ar threshold
is the sum, in KBytes, of ports allowed to build there.
.It Fl m
Force tty-style reporting.
.It Fl P Ar pathlist
Read list of
.Xr pkgpath 7
from file.
.It Fl p Ar parallel
Override value for the
.Dq parallel
property.
.Pp
Run big jobs on several cores on the same host, by using
MAKE_JOBS=k.
.Pp
Once such a job has started,
.Nm
will not start new jobs on the same host until the big job has
stolen enough cores from other finishing jobs.
.Pp
Only big ports which are safe for parallel building (annotated with
DPB_PROPERTIES = parallel in their Makefile) will be affected.
.Pp
It is advisable to set k to an integral fraction of the
number of cores available on a given host.
.Ar parameter
can be an integer, or of the form
.Sq /n ,
in which case,
.Nm
will set k to a fraction of the total number of jobs
on the machine, but never below 2.
.Pp
Defaults to
.Sq /2 .
.It Fl q
Don't quit while errors/locks are around.
.It Fl R
Rebuild existing packages based on discrepancies between the package
signature and what the port says it should be.
Concretely, use to run a partial bulk build after some library change.
.Pp
Note that
.Fl R
won't always work, as rebuilding a package when another version is already
installed is not supported.
Building in a chroot is strongly recommended.
.It Fl r
Random build order.
Disregard any kind of smart heuristics.
Useful to try to find missing build dependencies.
.It Fl S Ar logfile
Read
.Ar logfile
as an initial workdir size log.
.It Fl s
Compute workdir sizes before cleaning up, and stash them in log file
.Pa %L/size.log .
This will also maintain a rolling log of build sizes under
.Pa %f/build-stats/%a-size .
In order to save time,
.Nm
will actually not always compute new sizes for known directories, but mostly
for new ones, or when the package name changes.
.It Fl U
Insist on updating existing packages during dependency solving,
even if the new package apparently didn't change.
.It Fl u
Update existing packages during dependency solving.
Can be used to run a bulk-build on a machine with installed packages,
but might break a bit, since some packages only build on a clean machine
right now.
.It Fl X Ar pathlist
Read a list of
.Xr pkgpath 7
from file, and pass them along in the junk phase:
those are packages that should stay on the machine if they've been
installed by a dependency.
Can be used to avoid endlessly removing/reinstalling the most common
packages, e.g.,
.Pa devel/gmake .
.It Fl x
No tty report, only report really important things, like hosts going down
and coming back up, build errors, or builds not progressing.
.El
.Pp
.Nm
figures out in which order to build things on the fly, and constantly
displays information relative to what's currently building.
There's a list of what is currently running, one line per job.
Those jobs are ordered in strict chronological order, which means that
long running builds will tend to percolate to the top of the list.
Normal jobs look like this:
.Bd -literal -offset indent
www/mozilla-firefox(build) [9452] 41% unchanged for 92 seconds
.Ed
.Pp
This contains:
.Bl -dash
.It
an optional
.Sq ~
squiggle marker (see below),
.It
the pkgpath being built,
.It
the step currently being run,
.It
an optional
.Sq \&!
for ports with the
.Sq nojunk
property.
.It
an optional
.Sq +
for ports built in memory.
.It
the pid running that task (note that this is always a pid on the host
running dpb: for distributed builds, it will be an
.Xr ssh 1
to another machine),
.It
the current size of the log file (displayed as a percentage if previous
build statistics are available).
.It
and a possible notice that things might be stuck when
the log file doesn't change for long periods.
.El
.Pp
And fetch jobs look like this:
.Bd -literal -offset indent
<dist-3.0.tgz(#1) [4321] 25%
.Ed
.Pp
This contains:
.Bl -dash
.It
the file being fetched
.It
the number of the
.Ev MASTER_SITE
being tried
.It
the pid of the
.Xr ftp 1
process (note that fetch jobs are always local).
.It
a progress percentage.
.El
.Pp
This is followed by a host line, containing the name
of each host used by dpb.
Host names may be tagged with kde3 or kde4.
They are followed by a
.Sq `-'
for unresponsive hosts, and the pid of the ssh master
for distant hosts.
.Pp
This ends with a summary display:
.Bl -tag -width BB=
.It I=
number of built packages that can be installed.
.It B=
number of built packages, not yet known to be installable,
because of run depends that still need to be built.
.It Q=
number of packages in the queue, e.g., stuff that can be built now, assuming
we have a free slot.
.It T=
number of packages to build, where dependencies are not yet resolved.
.It F=
number of distfiles to fetch, when
.Fl f
is used.
.It !=
number of ignored packages.
Details in
.Pa engine.log .
.It L=
list of packages that cannot currently be built because of locks.
.It E=
list of packages in error, that cannot currently be built.
.It H=
list of packages that haven't shown up yet, usually due to nfs, but
watch out for revision bumps.
.El
.Pp
If those three lists are empty, they won't even show up.
Packages in errors may be followed by a
.Sq \&!
if they prevent junk from happening.
.Pp
Note that those numbers refer to pkgpaths known to
.Nm .
In general, those numbers will be slightly higher than the actual number
of packages being built, since several paths may lead to the same package.
.Pp
.Nm
uses some heuristics to try to maximise the queue as soon as possible.
There are also provisions for a feedback-directed build, where information from
previous builds can be used to try to build long-running jobs first.
.Pp
Similarly, fetches will use the continue option of
.Xr ftp 1 ,
since distfiles are checksummed after the fetch anyways.
.Ss THE SQUIGGLE HEURISTICS
However, on machines with lots of cores, the basic scheduling heuristics
yields a tail of very small jobs, where
.Nm
will mostly wait on
.Xr pkg_add 1
to solve dependencies.
Starting with
.Ox 5.5 ,
a new mechanism (squiggles) was introduced to counter-balance this effect:
big machines devote some of their cores to
.Sq squiggles ,
jobs that walk the queue in reverse, thus building smallest ports first.
As a result, small ports are built as a trickle alongside the largest ports,
thus offsetting the negative effect of the exponential queue for a large part.
.Pp
Note that
.Sq squiggles
can be a non-integral value, usually lower than 1, in which case they
represent the fraction of cores that should be affected to squiggles,
as decided randomly at the start of each build.
0.7 or 0.8 might be a good choice for dual core machines.
.Ss DPB PROPERTIES
The
.Xr bsd.port.mk 5
variable
.Ev DPB_PROPERTIES
may hold several annotations that only
.Nm
will look at.
These properties are as follows:
.Bl -tag -width pkgpathlong
.It Ar lonesome
Large port that stresses the memory limits of the machine, should be built
alone.
Prevents
.Nm
from scheduling anything else on the same host after it starts building.
.\".It Ar memoryhog
.It Ar noconfigurejunk
Port that looks for unneeded dependencies during its configure phase
(typically, optional tools like doxygen to rebuild documentation).
Similar to
.Ar nojunk
but less expensive, since the configure phase is most often limited in scope.
.It Ar nojunk
Port that hardcodes includes in its Makefile mechanisms.
Prevents
.Ar junk
from running while port is building.
.It Ar parallel
Port that can be built in parallel, uses
.Ev MAKE_JOBS
and several build slots.
.It Ar parallel2
Very large port that should be built in parallel, uses
.Ev MAKE_JOBS
and lots of build slots.
.It Ar tag:kde3
kde3 port that conflicts with kde4 ports.
Prevent scheduling ports with
.Ar tag:kde4
on the same host.
.It Ar tag:kde4
kde4 port that conflicts with kde3 ports.
Prevent scheduling ports with
.Ar tag:kde3
on the same host.
.El
.Sh THE SECURITY MODEL OF DPB
When
.Nm
is run as root, it uses a privilege drop model instead of the
dangerous privilege elevation model of
.Xr doas 1 .
When run as root, by default,
.Ar _pbuild
is used as the build and log user, and
.Ar _pfetch
is used as the fetch user.
.Bl -bullet
.It
Start
.Nm
as root.
.It
.Nm
will drop privileges for every operation except
.Xr pkg_add 1 ,
.Xr pkg_delete 1
and the
.Ar STARTUP
script.
.It
For cluster builds,
provide an
.Xr ssh 1
connection to distant hosts from root as root.
.It
.Ar build_user
is used to build stuff locally or distantly (can be per-host), using:
.Li chroot -u build_user /build_root
(with
.Pa /build_root
=
.Pa /
if there is no actual chroot needed).
It must have read access to ${DISTDIR} and ${PORTSDIR}, and write
access to ${WRKOBJDIR}, ${PACKAGE_REPOSITORY}, and ${PLIST_REPOSITORY}.
It does not require network access.
.It
.Ar LOG_USER
is used to open all log files.
.Ar LOG_USER
only needs to exist locally.
It needs write access to the log directories, including
${DISTDIR}/build-stats.
It does not need network access.
.It
.Ar FETCH_USER
is used to fetch distfiles and handle corresponding log info.
It needs write access to ${DISTDIR}, and network access.
Thus,
.Xr ftp 1
does not happen as root.
.It
.Ar _dpb
is used as a fail-safe for any other activities that do not require any rights.
.It
.Nm
creates local directories as root, then gives them to the appropriate user.
.El
.Sh LOCKS AND ERRORS
.Nm
still uses the normal ports tree mechanism while building, which includes
.Ev LOCKDIR .
When starting up
.Nm
will normally detect stale locks from old dpb runs, and remove them.
If this does not happen, builds will stay stuck in their initial stage,
that is:
.Ar show-prepare-results , patch , build
depending on the port.
A telltale message
.Sq Awaiting lock ...
can be found in the corresponding logfile
.Pa paths/pkgpath.log
.Pp
In addition, when building a package,
.Nm
produces a lockfile in the locks directory, whose name is deduced from
the basic pkgpath with slashes replaced by dots.
This lockfile is filled with such info as the build start time or the host,
or the needed dependencies for this pkgpath.
.Pp
The lockfile will also contain the name of a parent pkgpath, for paths that
were discovered as dependencies.
This is particularly useful for bogus paths, where it would be hard to
know where the path came from otherwise.
.Pp
At the end of a successful build, these lockfiles are removed.
The lock will stay around in case of errors.
.Po
raw
value from
.Xr wait 2
.Pc ,
and the name of the next task in the build pipeline (with todo=<nothing>
in case of failure during clean-up).
Normal list of tasks is:
.Ar depends prepare fetch patch configure build fake package clean .
.Pp
At the end of each job,
.Nm
rechecks the locks directory for existing lockfiles.
If some locks have vanished,
it will put the corresponding paths back in the queue and attempt
another build.
.Pp
This eases manual repairs: if a package does not build, the user can look
at the log, go to the port directory, fix the problem, and then remove the lock.
.Nm
will pick up the ball and keep building without interruption.
.Pp
It is perfectly safe to run several
.Nm
in parallel on the same machine.
This is not optimal, since each
.Nm
ignores the others, and only uses the lock info to avoid the other's
current work, but it can be handy: in an emergency, one can start a second
.Nm
to obtain a specific package right now, in parallel with the original
.Nm .
.Pp
Note that
.Nm
is very careful not to run two builds from the same pkgpath at the
same time, even on different machines:
in some cases, MULTI_PACKAGES and FLAVOR combinations may lead to the
same package being built simultaneously, and since the package repository
is shared, this can easily lead to trouble.
.Pp
Handling of shared log files and history is also done very carefully by
systematically appending to files or using atomic mv operations.
.Pp
For obvious reasons, this won't work as well with masters running on distinct
machines sharing their logs through NFS.
.Ss BUILD CYCLES
There are some various interdependencies in package builds that can be hard
to trace in case something goes wrong.
Refer to
.Pa summary.log
to fix those specific issues.
.Sh AFFINITY
.Nm
now maintains a list of pkgpath-per-host that are currently building in the
.Pa affinity
directory of its log directory, along with building-in-memory status.
.Pp
That information is only wiped out when a given build finishes successfully.
.Pp
Otherwise
.Nm
will try to restart that build on the same host, which can be handy if you
interrupt
.Nm
while it is building a large port, or if you remove a lock after fixing a
problem.
.Sh TAGS FOR EXCLUSIVE BUILDS
Back when we had kde3 and kde4, they couldn't be built simultaneously,
and a single host had to be exclusively building kde3 or kde4 ports at
a given moment.
.Pp
Conflicting ports had been annotated with
.Ev DPB_PROPERTIES Ns = Ns Ar tag:kde3 ,
.Ev DPB_PROPERTIES Ns = Ns Ar tag:kde4
respectively.
.Pp
More generally, with
.Ev DPB_PROPERTIES Ns = Ns Ar tag:A ,
.Ev DPB_PROPERTIES Ns = Ns Ar tag:B ,
.Nm
will keep track of tags.
For instance, if host
.Ar X
is building ports tagged with
.Ar A ,
then any port with tag
.Ar B
will be prevented from building on
.Ar X
until the next
.Ar junk
phase.
.Pp
This heavily relies on the
.Ar junk
stage to clean-up hosts periodically,
and it can even forcibly provoke a
.Ar junk
stage even if junk=0.
.Pp
This
.Sq force-junk
stage is actually implemented as a pseudo path called
.Ar junk-proxy ,
which does only junk.
.Pp
In order for builds to proceed gracefully, machines should start
in a clean slate, without any of the problematic ports installed.
.Pp
As a special-case, failing ports with a tag will not
interfere with clean-up, so that hosts do not get locked down to
a specific tag.
This also means that their dependencies
may vanish before human intervention addresses the problem.
.Pp
This is supposed to be an exceptional hack, helpful while porters
figure out how to remove the deadlock.
.Sh EXTERNAL CONTROL
By default
.Po
see
.Ar CONTROL
.Pc ,
.Nm
will create a Unix socket at
.Pa %L/control-%h-%$ ,
only accessible by
.Ar LOG_USER ,
that can accept a few commands, e.g.,
usable as
.Li nc -U path
.Pp
Current commands are as follows:
.Bl -tag -offset aaaa -width addhost
.It Cm addhost Ar hostline
Add a new host
.It Cm addpath Ar fullpkgpath ...
Add fullpkgpath to scan
.It Cm bye
close the socket connection.
.It Cm dontclean Ar pkgpath ...
Add new pkgpath to list of paths that should not be cleaned after build
.It Cm help
Self explanatory
.It Cm info Ar cores
Debug info for cores (to be extended to other data)
.It Cm rescan
Force
.Nm
to rescan all ignored paths (for various errors, including bogus dependencies)
.It Cm stats
Show the current stats line
.It Cm status Ar fullpkgpath ...
Show the current status of fullpkgpath, whether it's built, installable,
ready to build, to build later, along with current dependencies if
applicable.
.It Cm stub Ar fullpkgpath ...
Stub out
.Ar fullpkgpath
and unlock it if needed.
.It Cm wipe Ar fullpkgpath ...
Wipe out an existing lock: clean up the corresponding
.Ar fullpkgpath
on the appropriate host, then remove all lock and affinity info pertaining
to the port.
.It Cm wipehost Ar hostname ...
Remove all information relevant to a given host from
.Nm ,
including running jobs, locks, and affinity information.
.El
.Sh SHUTTING DOWN GRACEFULLY
.Nm
periodically checks for a file named
.Pa stop
in its log directory.
If this file exists, then it won't start new jobs, and shutdown when
the current jobs are finished unless
.Fl q .
.Pp
.Nm
also checks for files named
.Pa stop-<hostname>
in its log directory.
If such a file exists, then it won't start new jobs on
the corresponding machine.
.Sh FILES
Apart from producing packages,
.Nm
may create temporary files as
.Pa ${FULLDISTDIR}/${DISTFILE}.part .
.Pp
In fetch mode
.Po
.Fl f
and
.Fl F
.Pc ,
.Nm
populates
.Pa ${DISTDIR}/by_cipher/sha256
with links.
It also uses
.Pa ${DISTDIR}/distinfo
and
.Pa ${DISTDIR}/history
as a
.Sq permanent log :
.Bl -tag -width distinfo
.It distinfo
cache of distfiles checksum.
Contains all
.Xr sha256 1
checksums of known files under
.Pa ${DISTDIR} .
Fetching uses this to avoid re-checksumming known files.
.It history
Log of old files under distinfo.
After successfully scanning a full ports tree
.Po
.Nm Fl a
.Pc ,
the fetch engine knows precisely which files are needed by the build
(and their checksums).
Anything that is
.Bl -bullet
.It
recorded in distinfo but unneeded
.It
recorded in distinfo but with the wrong checksum
.It
not recorded in distinfo, but not needed
.El
will be entered at the end of history as a line:
.Pp
.Li ts SHA256 (file) = value
.Pp
with
.Ar ts
a timestamp from Unix epoch.
.Pp
When cleaning up old files, with a tool such as
.Xr clean-old-distfiles 1 ,
it is vital to check both the checksum and
the file name: since mirroring stores permanent links under
.Pa by_cipher ,
files which are still needed will appear in history under their old
checksums, as an indication the link should be removed, but possibly not
the file itself.
.El
.Pp
If
.Pa ${DISTDIR}
ever becomes corrupted,
removing
.Pa ${DISTDIR}/distinfo
will force
.Nm
into checking all files again.
.Pp
All those files belong to the
.Ar FETCH_USER
if it is defined.
They should be readable for the
.Ar build_user .
.Pp
.Nm
also records rolling build statistics under
.Pa ${DISTDIR}/build-stats/${ARCH} ,
and uses them automatically
.Po
see
.Ar STATS_BACKLOG
and
.Ar STATS_USED
.Pc
in the absence of
.Fl b Ar logfile .
That file belongs to the
.Ar LOG_USER
if it is defined.
.Pp
If
.Fl s
is used, size information for successful builds will be recorded under
.Pa ${DISTDIR}/build-stats/${ARCH}-size
.Po
by default, location adjustable with
.Fl S Ar sizelog
.Pc .
This is then reused for the mfs threshold option.
That file also belongs to the
.Ar LOG_USER
if it is defined.
.Pp
.Nm
also maintains a list of pkgpath frequencies
.Pa ${DISTDIR}/build-stats/${ARCH}-dependencies ,
filled at end of LISTING if
.Fl a .
This list will be automatically reused when restarting a build:
a quick LISTING of the most important dependencies will happen
before the general LISTING,
in order to prime further LISTING steps with most common ports first.
.Pp
.Nm
will also create a large number of log files under
.Pa ${PORTSDIR}/logs/${ARCH} ,
which will belong
to
.Ar LOG_USER
if it is defined:
.Bl -tag -width engine.log
.It Pa affinity/
Affinity information.
One file per full pkgpath, with slash replaced by dots
like so:
.Pa affinity/lang.ghc,-main .
.It Pa affinity.log
On startup
.Nm
reads existing affinity information, and records it in that log,
together with its pid.
This log just exists to verify, along with
.Pa engine.log ,
whether correct affinity was heeded.
.It Pa awaiting-locks.log
This is purely for gathering performance statistics, about how much
lock contention happened around
.Xr pkg_add 1
and
.Xr pkg_delete 1
usage.
Plotting cumulated time may help in fine-tuning squiggles parameters.
.It Pa build.log
Actual build log.
Each line summarizes build of a single pkgpath, as:
.Sq pkgpath host time logsize (detailed timing)[!]
where time is the actual build time in seconds, host is the machine name
where this occurred, logsize is the corresponding log file size,
and a ! is appended in case the build didn't succeed.
.Pp
The detailed timing info gives a run-down of the build, with clean, fetch,
prepare, patch (actually extract+patch), configure, build, fake, package, clean
detailed timing info.
Note that the actual build time starts at
.Sq extract
and finishes at
.Sq package .
.It Pa built-packages.log
The actual list of fullpkgname.tgz as they get built.
.It Pa cpu-concurrency.log
Shows the actual concurrency achieved as a result of job starvation /
parallel handling.
Only gets a new line when the value changes: pid timestamp jobs
.It Pa debug.log
contains various information related to the main engine spinning (RTFS, haven't
figured that one yet) along with the more useful warning and die traces that
happen when something wrong occurs.
Especially useful for the warning messages that tend to be overwritten by
subsequent displays.
Will also contain error messages pertaining to failure at parsing existing
lock files.
.It Pa dist/<distfile>.log
Log of the
.Xr ftp 1
process(es) that attempted to fetch the distfile.
.It Pa control-%h-%$
Default name for the external control socket.
.It Pa dump.log
A long log file generated at the end of build that yields any information
pertinent to ports still in the
.Sq to build
and the
.Sq built
queues.
See also
.Pa summary.log
for an expurged version of same.
.It Pa engine.log
Build engine log.
Each line corresponds to a state change for a pkgpath and starts with the pid
of
.Nm ,
plus a timestamp of the log entry.
.Bl -tag -width BB:
.It ^
pkgpath temporarily put aside, because a job is running in the same directory.
.It !
pkgpath ignored, either directly, or indirectly because a dependency was
ignored.
End of the line states reason why ignored.
.It A
affinity mismatch: path considered for build, but not the right host,
followed by the affinity information.
.It B
pkgpath built / distfile found.
.It C
forcible clean-up before building a port with a kde tag.
.It E
error in build or fetch.
.It F
distfile queued for download.
.It H
package still not found due to nfs on this run.
.It I
pkgpath can be installed.
.It J
job to build pkgpath started.
Also records the host used for the build.
.It K
kde mismatch, no build until host has been cleaned up.
.It L
job did not start, existing lock detected.
.It N
job did not finish.
The host may have gone down.
.It P
built package is no longer required for anything.
.It Q
pkgpath queued as buildable whenever a slot is free.
.It T
pkgpath to build / distfile to download.
.It V
pkgpath put back in the buildable queue, after job that was running in
the same directory returned.
.It W
only happens when the external control
.Cm wipe
command is used: pkgpath will be cleaned up, next log entry will be
.Sq N
since the job did not finish and is ready to restart.
.It X
only happens when rescanning after an error.
The engine temporarily locks paths that are incomplete (detained).
These will be kept in a separate list for later examination until the
end of the new scan.
.It x
only happens when rescanning after an error.
Releases a path for building after the new scan is finished.
.It Y
affinity mismatch, but job will start on the wrong host anyways, as the queue
contains no other buildable path.
.El
.Pp
The engine is no longer run after each package build event
because of performance considerations, so the
.Sq Q
and
.Sq I
changes may be delayed by a few
.Sq B .
.It Pa equiv.log
Lists of equivalent pkgpaths for the build, when default flavors and default subpackages have been resolved.
.It Pa fetch/bad.log
List of URLs that did not lead to a correct distfile, either because
they were not responding, or because of incorrect checksums.
.It Pa fetch/good.log
List of URLs that fetched correctly, along with timing statistics.
.It Pa fetch/manually.log
List of pkgpaths that require manual intervention, in human-readable form.
.It Pa <hostname>.sig.log
Complete library signature of the host.
.It Pa init.<hostname>.log
Captured output of the initialization job for each host.
.It Pa junk.log
Option
.Fl J
counts the number of dependencies directly added to decide when to run
.Nm pkg_delete Fl a .
This file sums up how many ports were built, and how many ports had
dependencies each time
.Nm
decides to junk.
.It Pa locks/
Directory where locks are created.
There are three types of locks:
.Bl -bullet
.It
pkgpath locks for building, where the slash in a pkgpath is replaced
with a dot like so:
.Pa locks/devel.make
to flatten the structure.
.It
distfile locks for fetching, using the distfile name without the path like so:
.Pa locks/distfile.dist .
.It
host locks for dependency handling and junking, like so:
.Pa locks/host:hostname .
.El
.It Pa packages/pkgname.log
one file or symlink per pkgname.
.It Pa paths/some/path.log
one file or symlink per pkgpath.
.It Pa performance.log
Some parts of
.Nm
are computationally intensive, such as the engine runs to determine
new stuff that can be built, and the actual display reports.
.Pp
Both those activities are rate-limited, so that
.Nm
doesn't run its engine at each new package build,
and doesn't update its display every time there is a phase change.
.Pp
Lines tagged with
.Sq ENG
correspond to the engine;
lines tagged with
.Sq REP
correspond to the display reports.
.Pp
Lines ending with a dash
.Sq -
correspond to new activity that didn't trigger
a computation.
.Pp
Other lines will feature a plus
.Sq +
for normal runs, or an exclamation point
.Sq !
for forced runs, followed by two numbers:
the next timestamp at which we'll be allowed to run, and
a measure of how much time it took to run this pass.
.Pp
That information is mostly relevant while
.Nm
is building lots of small packages very quickly.
.It Pa signature.log
Discrepancies between hosts that prevent them from starting up.
.It Pa size.log
Size of work directory at the end of each build, built only with
.Fl s .
.It Pa stats.log
Simple log of the B=... line summaries.
Mostly useful for making plots and tweaking performance.
.It Pa stop
Not a logfile at all, but a file created by the user to stop
.Nm
creating new jobs.
.It Pa stop-<hostname>
Not a logfile at all, but created by the user to stop hostname creating
new jobs.
.It Pa summary.log
A summary file generated at end of build that lists packages not built
or not installable, along with a reason for it.
This summarizes packages not built because of existing locks, because of
errors, but also because they depend on something that was not built.
.Pp
In that last case,
.Pa summary.log
contains a chain of dependencies leading to the problematic package, or
in case of build cycles, stopping at the first loop.
.It Pa term-report.log
Saves all terminal output, so that it can be replayed at hi speed with
.Xr dpb-replay 1 .
.It Pa vars.log
Logs the directories that were walked in the ports tree for dependency
information, including the path to a dependency that triggered this
particular step.
.El
.Sh DIAGNOSTICS
.Bl -tag -offset aaaa -width truc
.It Waiting for hosts to finish STARTUP...
Displayed on the console while
.Nm
is setting up hosts, getting essential data from the ports tree,
running a
.Ar STARTUP
script, collecting base library signatures.
.It stuck on <lockfilename>
Display on the console when
.Nm
detects a "frozen" port has happened outside of
.Nm Ns 's
purview, namely because the ports tree itself has that specific
port locked without
.Nm Ns 's
knowledge.
See
.Xr bsd.port.mk 5 ,
.Xr portlock 1 .
.It (Junk lock obtained for <host> at <time>)
.It (Junk lock released for <host> at <time>)
Printed in a
.Pa paths/pkgpath.log
file when attempting to get a
.Sq junk lock .
On a given host, all dependency operations are serialized.
The dependency computation itself is handled by the main
.Nm
process, which needs to know exactly which dependencies are used
at a given point, so that
.Ar junk
can clean up the host correctly.
In particular,
.Ar junk
will not clean up dependencies already scheduled for installation.
Ports that do not obtain the lock on first try are put to sleep.
.It Received IO
Printed in a
.Pa paths/pkgpath.log
file when woken up before trying attempting to obtain a
.Ar junk
lock again...
.It Woken up <fullpkgpath>
Printed in a
.Pa paths/pkgpath.log
when waking another task by sending it SIGIO,
so that it may attempt to obtain the junk lock again.
.It (Junk lock failure for <host> at <time>)
All ports sleeping for a
.Ar junk
lock are woken at the same time, so only one of them will obtain the lock,
and the others will fail and be put to sleep again.
.It Short-cut: depends already handled by <fullpkgpath>
Printed in a
.Pa paths/pkgpath.log
when a port wakes up after others that ran
.Xr pkg_add 1 .
As
.Nm
maintains dependencies for a given host globally, it coalesces depends lists
together.
.It Don't run junk because nojunk in <fullpkgpath>
Printed in a
.Pa paths/pkgpath.log
while evaluating whether to run
.Ar junk .
Normally,
.Ar junk
happens at regular intervals, but ports marked
.Sq nojunk
will delay that.
.Nm
still keeps track of attempted junks.
.It Still tainted: <bool>
A host may have a tag (kde3/kde4) that prevents building differently tagged
ports.
This will be cleansed by
.Ar junk
eventually.
This prints in
.Ar path/pkgpath.log
to indicate whether this particular
.Ar junk
will keep the host tainted with a tag or not.
.It Forced junk, retainting: <tag>
Printed at end of
.Ar prepare-results ,
when an eventual junk was run even though some ports still hold a tag.
.It Can't run junk because of lock on <fullpkgpath>
.Ar junk
can't happen because
.Ar fullpkgpath
is locked and is marked
.Sq nojunk .
.It Avoided depends for <dependencies>
As dependencies are handled globally per-host, some ports can avoid
.Xr pkg_add 1
altogether because another port already installed the correct dependencies.
.It SPINNING ON MAIN
Printed in
.Ar debug.log ,
this is an actual bug: the engine said it can build, there are cores available,
but
.Nm
can't start a new build job.
.It SPINNING ON FETCH
Printed in
.Ar debug.log ,
this is an actual bug: the engine said it can fetch, there are fetching
cores available, but
.Nm
can't start a new fetch job.
.It KILLED: <job> stuck at <somewhere>
Printed in
.Ar path/pkgpath.log
when a port exceeds its timeout.
.It !: <path> tried and didn't get it
Printed in
.Ar engine.log
Scanning the port didn't give us useful information.
See
.Ar vars.log
for gory details.
.El
.Sh BUGS AND LIMITATIONS
.Nm
performs best with lots of paths to build.
When just used to build a few ports, there's a high risk of starvation
as there are bottlenecks in parts of the tree.
.Pp
Fetch jobs don't deal with checksum changes yet:
if a fetch fails because of a wrong checksum, if you update the distinfo
file and remove the lock,
.Nm
won't pick it up.
.Pp
Note that
.Nm
does not manage installed packages in any intelligent way, it will just
call
.Xr pkg_add 1
during its depend stage to install its dependencies.
With
.Fl u ,
it will call pkg_add -r.
With
.Fl U ,
it will call pkg_add -r -D installed,
but there is nothing else going on.
This is especially true when using
.Fl R ,
ensure the machine is clean of possibly older packages first, or run
.Nm
with
.Fl U .
.Pp
In particular
.Fl R
and
.Fl J
together may lead to strange issues.
.Pp
On heterogeneous networks, calibration of build info and choice of speed
factors is not perfect, and somewhat a dark art.
Using distinct speed factors on a build log that comes from a single
machine works fine, but using the build info coming from several machines
does not work all that well.
.Pp
.Nm
should check
.Pa /usr/include
and
.Pa /usr/X11R6/include
for consistency, but it doesn't.
.Pp
When a host fails consistency check, there is not yet a way to re-add it
after fixing the problem.
You have to stop
.Nm ,
cleanup and restart.
.Pp
The default limits in
.Pa login.conf
are too small for bulk builds on any kind of parallel machines.
Bump number of processes, file descriptors, and memory.
.Pp
Even though
.Nm
tries really hard to check heterogeneous networks for sanity (checking
shared libraries and .la files), it is still dependent on the user to
make sure all the hosts build ports the same way.
.Pp
Make sure your NFS setup is consistent.
The ports dir itself should be exported or synchronized.
Distfiles, the package repository,  and the plist repository should be exported,
but WRKOBJDIR should not be on NFS unless you have absolutely no choice,
or if you exhibit deep masochistic tendencies.
Pay particular attention to discrepancies in
.Pa /etc/mk.conf .
.Pp
Also,
.Nm
connects to external hosts through
.Xr ssh 1 ,
relying on
.Xr ssh_config 5
for any special cases.
.Pp
When fetching distfiles,
.Nm
may freeze and spin in a tight loop while the last distfiles are being fetched.
This is definitely a bug, which has been around for quite some time, which
is a bit difficult to reproduce, and hasn't been fixed yet.
So if
.Nm
stops updating its display right around the end of fetch, you've hit the bug.
Just kill
.Nm
and restart it.
.Sh SEE ALSO
.Xr clean-old-distfiles 1 ,
.Xr dpb-replay 1 ,
.Xr proot 1 ,
.Xr pkgpath 7 ,
.Xr bulk 8
.Sh HISTORY
The original
.Nm dpb
command was written by Nikolay Sturm.
This version is a complete rewrite from scratch using all the stuff
we learnt over the years to make it better.
.Sh AUTHORS
.An Marc Espie Aq Mt espie@openbsd.org