.\"	$NetBSD: compat_freebsd.8,v 1.19 2018/02/10 08:54:22 maxv Exp $
.\"	from: 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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.\"    documentation and/or other materials provided with the distribution.
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.\"    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 February 10, 2018
.Dt COMPAT_FREEBSD 8
.Os
.Sh NAME
.Nm compat_freebsd
.Nd setup procedure for running FreeBSD binaries
.Sh DESCRIPTION
.Bf -symbolic
compat_freebsd is not maintained anymore, and new FreeBSD binaries cannot
be expected to work.
The compat_freebsd feature is available in NetBSD only to support the
FreeBSD tw_cli driver.
.Ef
.Pp
.Nx
supports running
.Fx
binaries.
Most binaries should work, except programs that use
.Fx Ns -specific
features.
These include i386-specific calls, such as syscons utilities.
The
.Fx
compatibility feature is active for kernels compiled
with the
.Dv COMPAT_FREEBSD
option enabled.
.Pp
A lot of programs are dynamically linked.
This means, that you will also need the
.Fx
shared libraries that the program depends on, and the runtime
linker.
Also, you will need to create a
.Dq shadow root
directory for
.Fx
binaries on your
.Nx
system.
This directory is named
.Pa /emul/freebsd .
Any file operations done by
.Fx
programs run under
.Nx
will look in this directory first.
So, if a
.Fx
program opens, for example,
.Pa /etc/passwd ,
.Nx
will
first try to open
.Pa /emul/freebsd/etc/passwd ,
and if that does not exist open the
.Sq real
.Pa /etc/passwd
file.
It is recommended that you install
.Fx
packages that include configuration files, etc under
.Pa /emul/freebsd ,
to avoid naming conflicts with possible
.Nx
counterparts.
Shared libraries should also be installed in the shadow tree.
.Pp
Generally, you will need to look for the shared libraries that
.Fx
binaries depend on only the first few times that you install a
.Fx
program on your
.Nx
system.
After a while, you will have a sufficient set of
.Fx
shared libraries on your system to be able to run newly imported
.Fx
binaries without any extra work.
.Ss Setting up shared libraries
How to get to know which shared libraries
.Fx
binaries need, and where
to get them? Basically, there are 2 possibilities (when following
these instructions: you will need to be root on your
.Nx
system to do the necessary installation steps).
.Pp
.Bl -enum -compact
.It
You have access to a
.Fx
system.
In this case you can temporarily install the binary there, see what
shared libraries it needs, and copy them to your
.Nx
system.
Example: you have just ftp-ed the
.Fx
binary of SimCity.
Put it on the
.Fx
system you have access to, and check which shared libraries it
needs by running
.Sq ldd sim :
.Bd -literal -offset indent
me@freebsd% ldd /usr/local/lib/SimCity/res/sim
/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)
.Ed
.Pp
You would need go get all the files from the last column, and
put them under
.Pa /emul/freebsd .
This means you eventually have these files on your
.Nx
system:
.Bl -item -compact
.It
.Pa /emul/freebsd/usr/X11R6/lib/libXext.so.6.0
.It
.Pa /emul/freebsd/usr/X11R6/lib/libX11.so.6.0
.It
.Pa /emul/freebsd/usr/lib/libc.so.2.1
.It
.Pa /emul/freebsd/usr/lib/libm.so.2.0
.It
.Pa /emul/freebsd/usr/lib/libgcc.so.261.0
.El
.Pp
Note that if you already have a
.Fx
shared library with a matching major revision number to the first
column of the
.Ic 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:
.Bl -item -compact
.It
.Pa /emul/freebsd/usr/lib/libc.so.2.0
.El
.Pp
and you find that the ldd output for a new binary you want to
install is:
.Bd -literal
\-lc.2 => /usr/lib/libc.so.2.1 (0x10144000)
.Ed
.Pp
You won't need to worry about copying
.Pa /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:
.Bl -item -compact
.It
.Pa /emul/freebsd/usr/lib/libc.so.2.1
.El
.Pp
Finally, you must make sure that you have the
.Fx
runtime linker and its config files on your system.
You should copy these files from the
.Fx
system to their appropriate place on your
.Nx
system (in the
.Pa /emul/freebsd
tree):
.Bl -item -compact
.It
.Pa usr/libexec/ld.so
.It
.Pa var/run/ld.so.hints
.El
.It
You don't have access to a
.Fx
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
.Pa /emul/freebsd
(i.e.
.Pa foo/bar
is installed as
.Pa /emul/freebsd/foo/bar ) :
.Bl -item -compact
.It
.Pa sbin/ldconfig
.It
.Pa usr/bin/ldd
.It
.Pa usr/lib/libc.so.x.y.z
.It
.Pa usr/libexec/ld.so
.El
.Pp
.Ic ldconfig
and
.Ic ldd
don't necessarily need to be under
.Pa /emul/freebsd ,
you can install them elsewhere in the system too.
Just make sure they don't conflict with their
.Nx
counterparts.
A good idea would be to install them in
.Pa /usr/local/bin
as
.Ic ldconfig-freebsd
and
.Ic ldd-freebsd .
.Pp
Run the
.Fx
ldconfig program with directory arguments in which the
.Fx
runtime linker should look for shared libs.
.Pa /usr/lib
are standard, you could run like the following:
.Bd -literal -offset indent
me@netbsd% mkdir -p /emul/freebsd/var/run
me@netbsd% touch /emul/freebsd/var/run/ld.so.hints
me@netbsd% ldconfig-freebsd /usr/X11R6/lib /usr/local/lib
.Ed
.Pp
Note that argument directories of ldconfig are
mapped to
.Pa /emul/freebsd/XXXX
by
.Nx Ns 's
compat code, and should exist as such on your system.
Make sure
.Pa /emul/freebsd/var/run/ld.so.hints
is existing when you run
.Fx Ns 's
ldconfig, if not, you may lose
.Nx Ns 's
.Pa /var/run/ld.so.hints .
.Fx
.Ic ldconfig
should be statically
linked, so it doesn't need any shared libraries by itself.
It will create the file
.Pa /emul/freebsd/var/run/ld.so.hints .
You should rerun the
.Fx
version of the ldconfig program each time you add a new shared library.
.Pp
You should now be set up for
.Fx
binaries which only need a shared libc.
You can test this by running the
.Fx
.Ic ldd
on itself.
Suppose that you have it installed as
.Ic ldd-freebsd ,
it should produce something like:
.Bd -literal -offset indent
me@netbsd% ldd-freebsd `which ldd-freebsd`
/usr/local/bin/ldd-freebsd:
	-lc.2 => /usr/lib/libc.so.2.1 (0x1001a000)
.Ed
.Pp
This being done, you are ready to install new
.Fx
binaries.
Whenever you install a new
.Fx
program, you should check if it needs shared libraries, and if so,
whether you have them installed in the
.Pa /emul/freebsd
tree.
To do this, you run the
.Fx
version
.Ic ldd
on the new program, and watch its output.
.Ic ldd
(see also the manual page for
.Xr ldd 1 )
will print a list
of shared libraries that the program depends on, in the
form -l<majorname> => <fullname>.
.Pp
If it prints
.Dq 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
.Fx
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.
.Pp
.It
In some cases,
.Fx
binary needs access to certain device file.
For example,
.Fx
X server software needs
.Fx
.Pa /dev/ttyv0
for ioctls.
In this case, create a symbolic link from
.Pa /emul/freebsd/dev/ttyv0
to a
.Xr wscons 4
device file like
.Pa /dev/ttyE0 .
You will need to have at least
.Cd options WSDISPLAY_COMPAT_SYSCONS
and probably also
.Cd options WSDISPLAY_COMPAT_USL
in your kernel (see
.Xr options 4
and
.Xr wscons 4 ) .
.El
.Ss Finding the necessary files
.Em Note :
the information below is valid as of the time this
document was written (June, 1995), but certain details
such as names of ftp sites, directories and distribution names
may have changed by the time you read this.
.Pp
The
.Fx
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 ftp site for the distributions is:
.Lk ftp://ftp.FreeBSD.org/pub/FreeBSD
.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
.Dq 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.
.Bd -literal -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
.Dq bindist.??
are tar-ed, gzipped and split, so you can extract contents by
.Dq cat bindist.?? | tar zpxf - .
.Pp
Extract the files from these gzipped tarfiles in your
.Pa /emul/freebsd
directory (possibly omitting or afterwards removing files you don't
need), and you are done.
.Sh BUGS
The information about
.Fx
distributions may become outdated.