COMPAT_OPENBSD(8) BSD System Manager's Manual COMPAT_OPENBSD(8)NAMEcompat_openbsd - setup for running OpenBSD binaries under emulation
DESCRIPTION
MirOS supports running OpenBSD binaries. Most binaries for OpenBSD 3.8
and below should work.
The OpenBSD compatibility feature is active for kernels compiled with the
COMPAT_OPENBSD option and the kern.emul.openbsd sysctl(8) enabled.
A lot of programs are dynamically linked. This means that the OpenBSD
shared libraries that the programs depend on and the runtime linker are
also needed. Additionally, a "shadow root" directory for OpenBSD binaries
on the MirOS system will have to be created. This directory is named
/emul/openbsd. Any file operations done by OpenBSD programs run under
MirOS will look in this directory first. So, if an OpenBSD program opens,
for example, /etc/passwd, MirOS will first try to open
/emul/openbsd/etc/passwd, and if that does not exist open the 'real'
/etc/passwd file. It is recommended that OpenBSD packages that include
configuration files, etc., be installed under /emul/openbsd, to avoid
naming conflicts with possible MirOS counterparts. Shared libraries
should also be installed in the shadow tree.
Generally, it will only be necessary to look for the shared libraries
that OpenBSD binaries depend on the first few times that OpenBSD programs
are installed on the MirOS system. After a while, there will be a suffi-
cient set of OpenBSD shared libraries on the system to be able to run
newly imported OpenBSD binaries without any extra work.
Setting up shared libraries
How to get to know which shared libraries OpenBSD binaries need, and
where to get them? Basically, there are two possibilities. (When follow-
ing these instructions, root privileges are required on the OpenBSD sys-
tem to perform the necessary installation steps).
1. Access to an OpenBSD system: In this case temporarily install the
binary there, see what shared libraries it needs, and copy them to
the MirOS system. Example: ftp the OpenBSD binary of SimCity. Put it
on the OpenBSD system, and check which shared libraries it needs by
running
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)
All the files from the last column should be placed under
/emul/openbsd. The following files would therefore be required on
the MirOS system:
/emul/openbsd/usr/X11R6/lib/libXext.so.6.0
/emul/openbsd/usr/X11R6/lib/libX11.so.6.0
/emul/openbsd/usr/lib/libc.so.2.1
/emul/openbsd/usr/lib/libm.so.2.0
/emul/openbsd/usr/lib/libgcc.so.261.0
Note that if an OpenBSD shared library with a matching major revi-
sion number to the first column of the 'ldd' output is already
present, it isn't necessary to copy the file named in the last
column to the MirOS system; the one already there should work. It is
advisable to copy the shared library anyway, if it is a newer ver-
sion. The old one can be removed. So, if this library exists on the
system:
/emul/openbsd/usr/lib/libc.so.2.0
and the ldd output for a new binary is:
-lc.2 => /usr/lib/libc.so.2.1 (0x10144000)
it isn't necessary to copy /usr/lib/libc.so.2.1 too, because the
program should work fine with the slightly older version. libc.so
can be replaced anyway, and that should leave:
/emul/openbsd/usr/lib/libc.so.2.1
Finally, the OpenBSD runtime linker and its config files must be
present on the system. These files should be copied from the OpenBSD
system to their appropriate place on the MirOS system (in the
/emul/openbsd tree):
usr/libexec/ld.so
var/run/ld.so.hints
2. No access to an OpenBSD system: In that case, get the extra files
from various ftp sites. Information on where to look for the various
files is appended below.
Retrieve the following files (from _one_ ftp site to avoid any ver-
sion mismatches), and install them under /emul/openbsd (i.e. foo/bar
is installed as /emul/openbsd/foo/bar):
sbin/ldconfig
usr/bin/ldd
usr/lib/libc.so.x.y
usr/libexec/ld.so
ldconfig and ldd don't necessarily need to be under /emul/openbsd,
they can be installed elsewhere in the system too. Just make sure
they don't conflict with their native MirOS counterparts. A good
idea would be to install them in /usr/local/bin as ldconfig-openbsd
and ldd-openbsd or adjust the environment variable PATH appropriate-
ly to include /emul/openbsd/{{,usr.}{,s}bin}.
Run the OpenBSD ldconfig program with directory arguments in which
the OpenBSD runtime linker should look for shared libs. /usr/lib is
standard. For example:
me@openbsd% mkdir -p /emul/openbsd/var/run
me@openbsd% touch /emul/freebsd/var/run/ld.so.hints
me@openbsd% ldconfig-openbsd /usr/X11R6/lib /usr/local/lib
Note that argument directories of ldconfig are mapped to
/emul/openbsd/XXXX by MirOS BSD's compat code, and should exist as
such on the MirOS system. Make sure
/emul/openbsd/var/run/ld.so.hints exists when running FreeBSD's
ldconfig; if not, MirOS BSD's /var/run/ld.so.hints could be lost.
OpenBSD ldconfig should be statically linked, so it doesn't need any
shared libraries by itself. It will create the file
/emul/openbsd/var/run/ld.so.hints. The OpenBSD version of the ldcon-
fig program should be rerun each time a new shared library is added.
The MirOS system should now be set up for OpenBSD binaries which
only need a shared libc. Test this by running the OpenBSD ldd on it-
self. Suppose that it is installed as ldd-openbsd, it should produce
something like:
me@mirbsd% ldd-openbsd $(which ldd-openbsd)
/usr/local/bin/ldd-freebsd:
-lc.2 => /usr/lib/libc.so.2.1 (0x1001a000)
This being done, new OpenBSD binaries can now be installed. Whenever
a new OpenBSD program is installed, it should be determined if it
needs shared libraries, and if so, whether they are installed in the
/emul/openbsd tree. To do this, run the OpenBSD 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>.
If it prints "not found" instead of <fullname> it means that an ex-
tra library is needed. Which library this is, is shown in <major-
name>, which will be of the form XXXX.<N>. Find a
libXXXX.so.<N>.<mm> on an OpenBSD ftp site, and install it on the
MirOS system. The XXXX (name) and <N> (major revision number) should
match; the minor number(s) <mm> are less important, though it is ad-
vised to take the most recent version.
Finding the necessary files
Note: the information below is valid as of Oct 2004, but certain details
such as names of ftp sites, directories and distribution names may have
changed since then.
OpenBSD distribution is available on a lot of ftp sites. Sometimes the
files are unpacked, and individual files can be retrieved, but mostly
they are stored in distribution sets, usually consisting of subdirec-
tories with gzipped tar files in them. The primary ftp site for the dis-
tribution is:
ftp.openbsd.org:/pub/OpenBSD
Mirror sites are described at:
www.openbsd.org/ftp.html
This distribution consists of a number of tar-ed and gzipped files. Nor-
mally, they're controlled by an install program, but the files can be re-
trieved "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 files
needed. Here is an example of a list of files that might be needed:
Needed Files
ld.so 5.0-RELEASE/base/base.??
ldconfig 5.0-RELEASE/base/base.??
ldd 5.0-RELEASE/base/base.??
libc.so.6 5.0-RELEASE/base/base.??
libX11.so.6 5.0-RELEASE/packages/x11/XFree86-libraries-??
libXt.so.6 5.0-RELEASE/packages/x11/XFree86-libraries-??
The files called "base.??" are tar-ed, gzipped and split, so they can be
extracted with "cat base.?? | tar zpxf -".
The XFree86 libraries are compressed with bzip2 and can be extracted with
"bzcat <file> | tar pxf -". Note: The bzip2 utilities are not part of a
base MirOS system. bzip2 can be added via packages(7) or ports(7).
Simply extract the files from these compressed tarfiles in the
/emul/openbsd directory (possibly omitting or afterwards removing un-
necessary files).
CAVEATScompat_openbsd only works on the i386 architecture.
BUGS
The information about OpenBSD releases may become outdated. This manual
page is too visibly derived from the freebsd one.
MirOS BSD #10-current October 26, 2004 3