.\"	$OpenBSD: compat_svr4.8,v 1.7 1999/07/09 13:35:36 aaron Exp $
.\"	$NetBSD: compat_svr4.8,v 1.1 1996/07/06 17:14:50 christos Exp $
.\"
.\" Copyright (c) 1996 Christos Zoulas
.\" All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\" 3. All advertising materials mentioning features or use of this software
.\"    must display the following acknowledgment:
.\"      This product includes software developed for the NetBSD Project
.\"      by Christos Zoulas
.\" 4. The name of the author may not be used to endorse or promote products
.\"    derived from this software without specific prior written permission
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
.\"
.\"	Stolen from compat_linux.8,v 1.2 1995/10/16 20:17:59 fvdl
.\"
.Dd July 6, 1996
.Dt compat_svr4 8
.Os
.Sh NAME
.Nm compat_svr4
.Nd setup procedure for running SVR4/iBCS2 binaries under emulation
.Sh DESCRIPTION
OpenBSD supports running SVR4/iBCS2 binaries. This code has been tested on
i386 and sparc systems. Most programs should work, but not ones that use
the /proc filesystem, sound, or threads (unfortunately ttsession uses threads).
.\" XXX: What else?
.Pp
The SVR4 compatibility feature is active
for kernels compiled with the
.Nm COMPAT_SVR4
option enabled.
.Pp
Most SVR4 programs are dynamically linked. This means that you will
also need the shared libraries that the program depends on and the
runtime linker. Also, you will need to create a "shadow root"
directory for SVR4 binaries on your OpenBSD system. This directory
is named /emul/svr4. Any file operations done by SVR4 programs
run under OpenBSD will look in this directory first. So, if a SVR4
program opens, for example, /etc/passwd, OpenBSD will
first try to open /emul/svr4/etc/passwd, and if that does not exist
open the 'real' /etc/passwd file. It is recommended that you install
SVR4 packages that include configuration files, etc under /emul/svr4,
to avoid naming conflicts with possible OpenBSD counterparts. Shared
libraries should also be installed in the shadow tree.
.Pp
The simplest way to setup your system for SVR4 biraries is:

.Bl -tag -width 123 -compact
.It 1.
Make the necessary directories:
.Pp
.Bl -tag -width 123 -compact -offset indent
.It (me@openbsd) mkdir -p /emul/svr4/{dev,etc}
.br
.It (me@openbsd) mkdir -p /emul/svr4/usr/{bin,lib}
.br
.It (me@openbsd) mkdir -p /emul/svr4/usr/openwin/{bin,lib}
.El
.Pp
.It 2.
Copy files from an svr4 system:
.Pp
.Bl -tag -width 123 -compact -offset indent
.It (me@svr4) cd /usr/lib
.br
.It (me@svr4) tar -cf -\ . | \e
.in +5
.It rsh openbsd 'cd /emul/svr4/usr/lib; tar -xpf -'
.in -5
.El
.Pp
If you are running openwindows:
.Pp
.Bl -tag -width 123 -compact -offset indent
.It (me@svr4) cd /usr/openwin/lib
.br
.It (me@svr4) tar -cf -\ . | \e
.in +5
.It rsh openbsd 'cd /emul/svr4/usr/openwin/lib; tar -xpf -'
.in -5
.El
.Pp
.It 3.
Setup the configuration files and devices:
.Pp
.Bl -tag -width 123 -compact -offset indent
.It (me@openbsd) cd /usr/src/etc/etc.svr4
.br
.It (me@openbsd) cp netconfig nsswitch.conf /emul/svr4/etc
.br
.It (me@openbsd) cp SVR4_MAKEDEV /emul/svr4/dev
.br
.It (me@openbsd) cd /emul/svr4/dev; ./SVR4_MAKEDEV all
.El
.El
.Pp
An alternative method is to mount a whole svr4 partition in /emul/svr4
and then override with other mounts /emul/svr4/etc and /emul/svr4/dev.
.Pp
Clearly, you cannot use a complete SVR4
.Pa /dev
directory as
.Pa /emul/svr4/dev ,
because other device nodes, such as
.Pa /dev/null ,
need to be OpenBSD device nodes.
.Sh BUGS
Many system calls are still not emulated.