"Tim W. Janes" writes:
> Hi,
> 
> How to I setup NetBSD1.2 for linux emulation?
> 
> The FAQ refers to ftp://ftp.enigma.net/pub/netbsd_i386 but this does
> not exist and I cannot find anything relevant on this server.
> 
> I understand that I need LINUX_COMPAT in the kernel and need to copy
> libraries from a linux system - but where do I put them?
> 
> Apologies for the low level of this request but I am stuck on how to proceed.


COMPAT_LINUX(8)		NetBSD System Manager's Manual	       COMPAT_LINUX(8)

NAME
     compat_linux - setup procedure for running Linux binaries

DESCRIPTION
     NetBSD supports running Linux binaries. This only applies to i386 systems
     for now. Both the a.out and ELF binary formats are supported. Most pro-
     grams should work, including the ones that use the Linux SVGAlib. Pro-
     grams that will not work include the Linux /proc filesystem (which is
     different from the optional NetBSD /proc filesystem), and i386-specific
     calls, such as enabling virtual 8086 mode. Currently, sound is only par-
     tially supported for Linux binaries (they will probably run, depending on
     what Linux sound support features are used).

     The Linux compatibility feature is active for kernels compiled with the
     COMPAT_LINUX option enabled.  If support for Linux a.out executables is
     desired, the EXEC_AOUT option should be enabled in addition to
     COMPAT_LINUX. Similarly, if support for Linux 32-bit and/or 64-bit ELF
     executables is desired, the EXEC_ELF32 and/or EXEC_ELF64 options (respec-
     tively) should be enabled in addition to COMPAT_LINUX.

     A lot of programs are dynamically linked. This means, that you will also
     need the Linux shared libraries that the program depends on, and the run-
     time linker. Also, you will need to create a "shadow root" directory for
     Linux binaries on your NetBSD system. This directory is named /emul/lin-
     ux. Any file operations done by Linux programs run under NetBSD will look
     in this directory first. So, if a Linux program opens, for example,
     /etc/passwd, NetBSD will first try to open /emul/linux/etc/passwd, and if
     that does not exist open the 'real' /etc/passwd file. It is recommended
     that you install Linux packages that include configuration files, etc un-
     der /emul/linux, to avoid naming conflicts with possible NetBSD counter-
     parts. 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 NetBSD system. After a while, you will have a sufficient set
     of Linux shared libraries on your system to be able to run newly imported
     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 NetBSD system to do the
     necessary installation steps).

     1.	  You have access to a Linux system. In this case you can temporarily
	  install the binary there, see what shared libraries it needs, and
	  copy them to your NetBSD 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 lin-
	  uxxdoom':

		(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 /emul/linux, with the names in the first column as sym-
	  bolic links pointing to them. This means you eventually have these
	  files on your NetBSD system:


	  /emul/linux/usr/X11/lib/libXt.so.3.1.0
	  /emul/linux/usr/X11/lib/libXt.so.3 (symbolic link to the above)
	  /emul/linux/usr/X11/lib/libX11.so.3.1.0
	  /emul/linux/usr/X11/lib/libX11.so.3 (symbolic link to the above)
	  /emul/linux/lib/libc.so.4.6.29
	  /emul/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:

	  /emul/linux/lib/libc.so.4.6.27
	  /emul/linux/lib/libc.so.4 -> /emul/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:

	  /emul/linux/lib/libc.so.4.6.29
	  /emul/linux/lib/libc.so.4 -> /emul/linux/lib/libc.so.4.6.29

	  Please note that the symbolic link mechanism is only needed for Lin-
	  ux binaries, the NetBSD 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 NetBSD sys-
	  tem (in the /emul/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 (from _one_ ftp site to avoid any ver-
	  sion mismatches), and install them under /emul/linux (i.e. /foo/bar
	  is installed as /emul/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 /emul/linux, you
	  can install them elsewhere in the system too. Just make sure they
	  don't conflict with their NetBSD counterparts. A good idea would be
	  to install them in /usr/local/bin as ldconfig-linux and ldd-linux.

	  Create the file /emul/linux/etc/ld.so.conf, containing the directo-
	  ries 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 /emul/linux/XXXX by NetBSD'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 /emul/linux/etc/ld.so.cache You should rerun the Linux version
	  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@netbsd) 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
	  /emul/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.


   Setting up other files
     Newer version of Linux use /etc/nsswitch.conf for network information,
     such as YP and DNS. You must create or get a valid copy of this file and
     put it in /emul/linux/etc.


   Finding the necessary files.
     [ Note: As of March, 1997, a reasonable set of Linux libraries and other
     files needed for Linux emulation may be obtained from
	   ftp://ftp.freebsd.org/pub/FreeBSD/distfiles/linux_lib-2.3.tar.gz
     It is recommended you try to retrieve this file (or a more recent ver-
     sion) from ftp.freebsd.org first as this tar file contains everything one
     typically needs and is is very simple to use for this application. Fail-
     ing that, see the instructions below.  ]

     Note: the information below is valid as of the time 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 /emul/linux direc-
     tory (possibly omitting or afterwards removing files you don't need), and
     you are done.


   Programs using SVGAlib
     SVGAlib binaries require some extra care. The pcvt virtual console driver
     has to be in the kernel for them to work, and you will also have to cre-
     ate some symbloic links in the /emul/linux/dev directory, namely:


     /emul/linux/dev/console -> /dev/tty
     /emul/linux/dev/mouse -> whatever device your mouse is connected to
     /emul/linux/dev/ttyS0 -> /dev/tty00
     /emul/linux/dev/ttyS1 -> /dev/tty01

     Be warned: the first link mentioned here makes SVGAlib binaries work, but
     may confuse others, so you may have to remove it again at some point.

BUGS
     The information about Linux distributions may become outdated.

     Pathnames pointed to by symbolic links are not looked up in the shadow
     root when running a Linux executable. This is not consistent.

4th Berkeley Distribution	 April 5, 1997				     5