path: root/share/man/man8/compat_freebsd.8

.\"	$OpenBSD: compat_freebsd.8,v 1.6 1999/07/09 13:35:36 aaron Exp $
.\"	$NetBSD: compat_linux.8,v 1.1 1995/03/05 23:30:36 fvdl Exp $
.\"
.\" Copyright (c) 1995 Frank van der Linden
.\" All rights reserved.
.\"
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.\" modification, are permitted provided that the following conditions
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.\"    notice, this list of conditions and the following disclaimer in the
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.\" 3. All advertising materials mentioning features or use of this software
.\"    must display the following acknowledgement:
.\"      This product includes software developed for the NetBSD Project
.\"      by Frank van der Linden
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.\"    derived from this software without specific prior written permission
.\"
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.Dd June 4, 1995
.Dt compat_freebsd 8
.Os
.Sh NAME
.Nm compat_freebsd
.Nd setup procedure for running FreeBSD binaries under emulation
.Sh DESCRIPTION
OpenBSD supports running FreeBSD binaries. Most binaries should work,
except programs that use FreeBSD-specific features. These include
i386-specific calls, such as syscons utilities, and audio devices.
.Pp
The FreeBSD compatibility feature is active for kernels compiled
with the
.Nm COMPAT_FREEBSD
option enabled.
.Pp
A lot of programs are dynamically linked. This means, that you will
also need the FreeBSD shared libraries that the program depends on, and
the runtime linker. Also, you will need to create a "shadow root"
directory for FreeBSD binaries on your OpenBSD system. This directory
is named /emul/freebsd. Any file operations done by FreeBSD programs
run under OpenBSD will look in this directory first. So, if a FreeBSD
program opens, for example, /etc/passwd, OpenBSD will
first try to open /emul/freebsd/etc/passwd, and if that does not exist
open the 'real' /etc/passwd file. It is recommended that you install
FreeBSD packages that include configuration files, etc under /emul/freebsd,
to avoid naming conflicts with possible OpenBSD counterparts. Shared
libraries should also be installed in the shadow tree.
.Pp
Generally, you will need to look for the shared libraries that FreeBSD
binaries depend on only the first few times that you install a FreeBSD
program on your OpenBSD system. After a while, you will have a sufficient
set of FreeBSD shared libraries on your system to be able to run newly
imported FreeBSD binaries without any extra work.

.Ss Setting up shared libraries
How to get to know which shared libraries FreeBSD binaries need, and where
to get them? Basically, there are 2 possibilities (when following
these instructions: you will need to be root on your OpenBSD system to
do the necessary installation steps).

.Bl -tag -width 123 -compact
.It 1.
You have access to a FreeBSD system. In this case you can
temporarily install the binary there, see what shared libraries
it needs, and copy them to your OpenBSD system. Example: you have
just ftp-ed the FreeBSD binary of SimCity. Put it on the FreeBSD
system you have access to, and check which shared libraries it
needs by running `ldd sim':
.Pp
.Bl -tag -width 123 -compact -offset indent
.It me@freebsd% ldd /usr/local/lib/SimCity/res/sim
.nf
/usr/local/lib/SimCity/res/sim:
	-lXext.6 => /usr/X11R6/lib/libXext.so.6.0 (0x100c1000)
	-lX11.6 => /usr/X11R6/lib/libX11.so.6.0 (0x100c9000)
	-lc.2 => /usr/lib/libc.so.2.1 (0x10144000)
	-lm.2 => /usr/lib/libm.so.2.0 (0x101a7000)
	-lgcc.261 => /usr/lib/libgcc.so.261.0 (0x101bf000)
.fi
.El
.Pp
You would need go get all the files from the last column, and
put them under /emul/freebsd. This means you eventually have
these files on your OpenBSD system:
.Pp
.nf
/emul/freebsd/usr/X11R6/lib/libXext.so.6.0
/emul/freebsd/usr/X11R6/lib/libX11.so.6.0
/emul/freebsd/usr/lib/libc.so.2.1
/emul/freebsd/usr/lib/libm.so.2.0
/emul/freebsd/usr/lib/libgcc.so.261.0
.fi
.Pp
Note that if you already have a FreeBSD shared library with a
matching major revision number to the first column of the 'ldd'
output, you won't need to copy the file named in the last column
to your system, the one you already have should work. It is
advisable to copy the shared library anyway if it is a newer version,
though. You can remove the old one. So, if you have these libraries
on your system:
.Pp
.nf
/emul/freebsd/usr/lib/libc.so.2.0
.fi
.Pp
and you find that the ldd output for a new binary you want to
install is:
.nf
.Pp
	-lc.2 => /usr/lib/libc.so.2.1 (0x10144000)
.fi
.Pp
you won't need to worry about copying /usr/lib/libc.so.2.1 too,
because the program should work fine with the slightly older version.
You can decide to replace the libc.so anyway, and that should leave
you with:
.Pp
.nf
/emul/freebsd/usr/lib/libc.so.2.1
.fi
.Pp
Finally, you must make sure that you have the FreeBSD runtime linker
and its config files on your system. You should copy these
files from the FreeBSD system to their appropriate place on your
OpenBSD system (in the /emul/freebsd tree):
.Pp
.nf
usr/libexec/ld.so
var/run/ld.so.hints
.fi
.Pp
.It 2.
You don't have access to a FreeBSD system. In that case, you
should get the extra files you need from various ftp sites.
Information on where to look for the various files is appended
below. For now, let's assume you know where to get the files.
.Pp
Retrieve the following files (from _one_ ftp site to avoid
any version mismatches), and install them under /emul/freebsd
(i.e. foo/bar is installed as /emul/freebsd/foo/bar):
.Pp
.nf
sbin/ldconfig
usr/bin/ldd
usr/lib/libc.so.x.y.z
usr/libexec/ld.so
.fi
.Pp
ldconfig and ldd don't necessarily need to be under /emul/freebsd,
you can install them elsewhere in the system too. Just make sure
they don't conflict with their OpenBSD counterparts. A good idea
would be to install them in /usr/local/bin as ldconfig-freebsd and
ldd-freebsd.
.Pp
Run the FreeBSD ldconfig program with directory arguments in
which the FreeBSD runtime linker should look for shared libs.
/usr/lib are standard, you could run like the following:
.Pp
.Bl -tag -width 123 -compact -offset indent
.It me@openbsd% mkdir -p /emul/freebsd/var/run
.It me@openbsd% touch /emul/freebsd/var/run/ld.so.hints
.It me@openbsd% ldconfig-freebsd /usr/X11R6/lib /usr/local/lib
.El
.Pp
Note that argument directories of ldconfig are
mapped to /emul/freebsd/XXXX by
OpenBSD's compat code, and should exist as such on your system.
Make sure /emul/freebsd/var/run/ld.so.hints exists when you run
FreeBSD's ldconfig, if not, you may lose OpenBSD's /var/run/ld.so.hints.

FreeBSD ldconfig should be statically
linked, so it doesn't need any shared libraries by itself.
It will create the file /emul/freebsd/var/run/ld.so.hints.
You should rerun the FreeBSD version of the ldconfig program
each time you add a new shared library.
.Pp
You should now be set up for FreeBSD binaries which only need
a shared libc. You can test this by running the FreeBSD ldd
on itself. Suppose that you have it installed as ldd-freebsd, it
should produce something like:
.Pp
.Bl -tag -width 123 -compact -offset indent
.It me@openbsd% ldd-freebsd `which ldd-freebsd`
.nf
/usr/local/bin/ldd-freebsd:
	-lc.2 => /usr/lib/libc.so.2.1 (0x1001a000)
.fi
.El
.Pp
This being done, you are ready to install new FreeBSD binaries.
Whenever you install a new FreeBSD program, you should check
if it needs shared libraries, and if so, whether you have
them installed in the /emul/freebsd tree. To do this, you run
the FreeBSD version ldd on the new program, and watch its output.
ldd (see also the manual page for ldd(1)) will print a list
of shared libraries that the program depends on, in the
form -l<majorname> => <fullname>.
.Pp
If it prints "not found" instead of <fullname> it means that
you need an extra library. Which library this is, is shown
in <majorname>, which will be of the form XXXX.<N>
You will need to find a libXXXX.so.<N>.<mm> on a FreeBSD ftp site,
and install it on your system. The XXXX (name) and <N> (major
revision number) should match; the minor number(s) <mm> are
less important, though it is advised to take the most
recent version.
.El

.Ss Finding the necessary files.
.Nm Note:
the information below is valid as of the time this
document was written (Jun, 1995), but certain details
such as names of ftp sites, directories and distribution names
may have changed by the time you read this.
.Pp
FreeBSD distribution is
available on a lot of ftp sites. Sometimes the files are unpacked,
and you can get the individual files you need, but mostly they
are stored in distribution sets, usually consisting of subdirectories
with gzipped tar files in them. The primary ftp sites for the
distributions are:
.Pp
.nf
ftp.freebsd.org:/pub/FreeBSD
.fi
.Pp
Mirror sites are described on:
.Pp
.nf
ftp.freebsd.org:/pub/FreeBSD/MIRROR.SITES
.fi
.Pp
This distribution consists of a number of tar-ed and gzipped files,
Normally, they're controlled by an install program, but you can
retrieve files "by hand" too. The way to look something up is to retrieve all
the files in the distribution, and ``tar ztvf'' through them for the file
you need. Here is an example of a list of files that you might need.
.Pp
.Bd -unfilled -offset indent
Needed                 Files

ld.so                  2.0-RELEASE/bindist/bindist.??
ldconfig               2.0-RELEASE/bindist/bindist.??
ldd                    2.0-RELEASE/bindist/bindist.??
libc.so.2              2.0-RELEASE/bindist/bindist.??
libX11.so.6.0          2.0-RELEASE/XFree86-3.1/XFree86-3.1-bin.tar.gz
libX11.so.6.0          XFree86-3.1.1/X311bin.tgz
libXt.so.6.0           2.0-RELEASE/XFree86-3.1/XFree86-3.1-bin.tar.gz
libXt.so.6.0           XFree86-3.1.1/X311bin.tgz
.\" libX11.so.3            oldlibs
.\" libXt.so.3             oldlibs
.Ed
.Pp
The Files called ``bindist.??'' are tar-ed, gzipped and split,
so you can extract contents by ``cat bindist.?? | tar zpxf -''.
.Pp
Extract the files from these gzipped tarfiles in your /emul/freebsd directory
(possibly omitting or afterwards removing files you don't need), and you
are done.
.Sh BUGS
The information about FreeBSD distributions may become outdated.