Date: Wed, 20 Sep 1995 09:27:00 -0500 From: Rich Murphey <rich@lamprey.utmb.edu> To: FreeBSD-current@freefall.FreeBSD.org Subject: linux compatibility man page Message-ID: <199509201427.JAA08552@id.slip.bcm.tmc.edu>
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I took netbsd's man page for linux compatibility and added a
brief installation guide. I've sent Jordan the nroff source
for review.
Any suggestions are welcome!
Many thanks to Soren Schmidt for the emulator itself! Rich
COMPAT LINUX(8) UNIX System Manager's Manual COMPAT LINUX(8)
- -
NAME
COMPAT LINUX - setup procedure for running Linux binaries
-
INSTALL
In order to run static and dynamicly linked Linux binaries, you need a
kernel configured with options COMPAT LINUX. Include options SYSVSHM as
-
well if you plan to run the linux version of doom.
cd /sys/i386/conf
echo options '"COMPAT LINUX"' >> GENERIC
-
echo options SYSVSHM >> GENERIC
config GENERIC
cd /sys/compile/GENERIC
make depend; make
make install
If you don't already have it, build the loadable kernel module
/lkm/linux mod.o.
-
cd /usr/src/lkm/linux
make all install clean
Once you have both the kernel and lkm installed, invoke
linux
as root to load the emulator into the kernel.
TESTING
To test the emulator using the linux version of the game doom, first get
the linux shared libraries.
mkdir /compat/linux
cd /compat/linux
ncftp ftp.freebsd.org:pub/FreeBSD/2.0.5-RELEASE/xperimnt/linux-emu/linux-emu.tar.gz
tar xzf linux-emu.tar.gz
rm -rf usr lkm linux-emu.tar.gz
The lkm and usr portion of this tar file are redundant since you already
have the lkm and /usr/bin/linux. Next install doom itself.
ncftp ftp.freebsd.org:pub/FreeBSD/2.0.5-RELEASE/xperimnt/linux-emu/linux-doom-1.8.tar.gz
tar xzf linux-doom-1.8.tar.gz
cd doom-1.8
xdoom
DESCRIPTION
Most Linux binaries should work, except programs that use Linux-specific
features. These include the Linux /proc filesystem (which is different
from the optional FreeBSD /proc filesystem), and i386-specific calls,
such as enabling virtual 8086 mode.
Many linux programs are dynamically linked. So you will also need the
Linux shared libraries that the program depends on, and the runtime link-
er. Also, you will need to create a "shadow root" directory for Linux
binaries on your FreeBSD system. This directory is named /compat/linux.
Any file operations done by Linux programs run under FreeBSD will look in
this directory first. So, if a Linux program opens, for example,
/etc/passwd, FreeBSD will first try to open /compat/linux/etc/passwd, and
if that does not exist open the packages that include configuration
files, etc under /compat/linux, to avoid naming conflicts with possible
FreeBSD counterparts. Shared libraries should also be installed in the
shadow tree.
Generally, you will need to look for the shared libraries that Linux bi-
naries depend on only the first few times that you install a Linux pro-
gram on your FreeBSD system. After a while, you will have a sufficient
set of Linux shared libraries on your system to be able to run newly im-
ported Linux binaries without any extra work.
Setting up shared libraries
How to get to know which shared libraries Linux binaries need, and where
to get them? Basically, there are 2 possibilities (when following these
instructions: you will need to be root on your FreeBSD system to do the
necessary installation steps).
1. If you have access to a Linux system, see what shared libraries it
needs, and copy them to your FreeBSD system. Example: you have just
ftp-ed the Linux binary of Doom. Put it on the Linux system you have
access to, and check which shared libraries it needs by running `ldd
linuxxdoom':
(me@linux) ldd linuxxdoom
libXt.so.3 (DLL Jump 3.1) => /usr/X11/lib/libXt.so.3.1.0
libX11.so.3 (DLL Jump 3.1) => /usr/X11/lib/libX11.so.3.1.0
libc.so.4 (DLL Jump 4.5pl26) => /lib/libc.so.4.6.29
You would need go get all the files from the last column, and put
them under /compat/linux, with the names in the first column as sym-
bolic links pointing to them. This means you eventually have these
files on your FreeBSD system:
/compat/linux/usr/X11/lib/libXt.so.3.1.0
/compat/linux/usr/X11/lib/libXt.so.3 (symbolic link to the above)
/compat/linux/usr/X11/lib/libX11.so.3.1.0
/compat/linux/usr/X11/lib/libX11.so.3 (symbolic link to the above)
/compat/linux/lib/libc.so.4.6.29
/compat/linux/lib/libc.so.4 (symbolic link to the above)
Note that if you already have a Linux 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 re-
move the old one, as long as you make the symbolic link point to the
new one. So, if you have these libraries on your system:
/compat/linux/lib/libc.so.4.6.27
/compat/linux/lib/libc.so.4 -> /compat/linux/lib/libc.so.4.6.27
and you find that the ldd output for a new binary you want to in-
stall is:
libc.so.4 (DLL Jump 4.5pl26) => /lib/libc.so.4.6.29
you won't need to worry about copying /lib/libc.so.4.6.29 too, be-
cause 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:
/compat/linux/lib/libc.so.4.6.29
/compat/linux/lib/libc.so.4 -> /compat/linux/lib/libc.so.4.6.29
Please note that the symbolic link mechanism is only needed for Lin-
ux binaries, the FreeBSD runtime linker takes care of looking for
matching major revision numbers itself, you don't need to worry
about that.
Finally, you must make sure that you have the Linux runtime linker
and its config files on your system. You should copy these files
from the Linux system to their appropriate place on your FreeBSD
system (to the /compat/linux tree):
/lib/ld.so
/etc/ld.so.cache
/etc/ld.so.config
2. You don't have access to a Linux 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.
Retrieve the following files (all from the same ftp site to avoid
any version mismatches), and install them under /compat/linux (i.e.
/foo/bar is installed as /compat/linux/foo/bar):
/sbin/ldconfig
/usr/bin/ldd
/lib/libc.so.x.y.z
/lib/ld.so
ldconfig and ldd don't necessarily need to be under /compat/linux,
you can install them elsewhere in the system too. Just make sure
they don't conflict with their FreeBSD counterparts. A good idea
would be to install them in /usr/local/bin as ldconfig-linux and
ldd-linux.
Create the file /compat/linux/etc/ld.so.conf, containing the direc-
tories in which the Linux runtime linker should look for shared
libs. It is a plain text file, containing a directory name on each
line. /lib and /usr/lib are standard, you could add the following:
/usr/X11/lib
/usr/local/lib
Note that these are mapped to /compat/linux/XXXX by FreeBSD's compat
code, and should exist as such on your system.
Run the Linux ldconfig program. It should be statically linked, so
it doesn't need any shared libraries by itself. It will create the
file /compat/linux/etc/ld.so.cache You should rerun the Linux ver-
sion of the ldconfig program each time you add a new shared library.
You should now be set up for Linux binaries which only need a shared
libc. You can test this by running the Linux ldd on itself. Suppose
that you have it installed as ldd-linux, it should produce something
like:
(me@FreeBSD) ldd-linux `which ldd-linux`
libc.so.4 (DLL Jump 4.5pl26) => /lib/libc.so.4.6.29
This being done, you are ready to install new Linux binaries. When-
ever you install a new Linux program, you should check if it needs
shared libraries, and if so, whether you have them installed in the
/compat/linux tree. To do this, you run the Linux 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 <majorname> (<jumpversion>) => <fullname>.
If it prints "not found" in stead of <fullname> it means that you
need an extra library. Which library this is, is shown in <major-
name>, which will be of the form libXXXX.so.<N> You will need to
find a libXXXX.so.<N>.<mm> on a Linux 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 ad-
vised to take the most recent version.
Finding the necessary files.
Note: the information below is valid as of the ime this document was
written (March, 1995), but certain details such as names of ftp sites,
directories and distribution names may have changed by the time you read
this.
Linux is distributed by several groups that make their own set of bina-
ries that they distribute. Each distribution has its own name, like
"Slackware" or "Yggdrasil". The distributions are available on a lot of
ftp sites. Sometimes the files are unpacked, and you can get the individ-
ual files you need, but mostly they are stored in distribution sets, usu-
ally consisting of subdirectories with gzipped tar files in them. The
primary ftp sites for the distributions are:
sunsite.unc.edu:/pub/Linux/distributions
tsx-11.mit.edu:/pub/linux/distributions
Some European mirrors:
ftp.luth.se:/pub/linux/distributions
ftp.demon.co.uk:/pub/linux/distributions
src.doc.ic.ac.uk:/packages/linux/distributions
For simplicity, let's concentrate on Slackware here. This distribution
consists of a number of subdirectories, containing separate packages.
Normally, they're controlled by an install program, but you can retrieve
files "by hand" too. First of all, you will need to look in the "con-
tents" subdir of the distribution. You will find a lot of small textfiles
here describing the contents of the seperate packages. The fastest way to
look something up is to retrieve all the files in the contents subdirec-
tory, and grep through them for the file you need. Here is an example of
a list of files that you might need, and in which contents-file you will
find it by grepping through them:
Needed Package
ld.so ldso
ldconfig ldso
ldd ldso
libc.so.4 shlibs
libX11.so.6.0 xf lib
-
libXt.so.6.0 xf lib
-
libX11.so.3 oldlibs
libXt.so.3 oldlibs
So, in this case, you will need the packages ldso, shlibs, xf lib and
-
oldlibs. In each of the contents-files for these packages, look for a
line saying "PACKAGE LOCATION", it will tell you on which 'disk' the
package is, in our case it will tell us in which subdirectory we need to
look. For our example, we would find the following locations:
Package Location
ldso diska2
shlibs diska2
oldlibs diskx6
xf lib diskx9
-
The locations called "diskXX" refer to the "slakware/XX" subdirectories
of the distribution, others may be found in the "contrib" subdirectory.
In this case, we could now retrieve the packages we need by retrieving
the following files (relative to the root of the Slackware distribution
tree):
slakware/a2/ldso.tgz
slakware/a2/shlibs.tgz
slakware/x6/oldlibs/tgz
slakware/x9/xf lib.tgz
-
Extract the files from these gzipped tarfiles in your /compat/linux di-
rectory (possibly omitting or afterwards removing files you don't need),
and you are done.
BUGS
The information about Linux distributions may become outdated.
SEE ALSO
ftp.freebsd.org:pub/FreeBSD/2.0.5-RELEASE/xperimnt/linux-emu/README
/usr/src/sys/i386/ibcs2/README.iBCS2
4th Berkeley Distribution March 2, 1995 5
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