NetBSD/share/man/man8/compat_svr4.8

.\"	$NetBSD: compat_svr4.8,v 1.13 1999/03/17 20:31:19 garbled Exp $
.\"
.\" Copyright (c) 1996 Christos Zoulas
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.\"    must display the following acknowledgment:
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.\"      by Christos Zoulas
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.\"	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
.Sh DESCRIPTION
.Nx
supports running SVR4/iBCS2 binaries. This code has been tested on
i386 (with binaries from SCO OpenServer and XENIX) and sparc (with binaries
from Solaris) systems. Most programs should work, but not ones that use
or depend on:
.sp
.Bl -tag -width 123 -compact -offset indent
.It kernel internal data structures
.br
.It the /proc filesystem
.br
.It the ticotsord loopback rpc mechanism (nis uses this)
.br
.It sound and video interfaces
.br
.It threads (ttsession uses threads)
.br
.It the streams administrative driver
.El
.sp
The SVR4 compatibility feature is active
for kernels compiled with the
.Dv COMPAT_SVR4
option enabled.
Since support for ELF executables is included
only if the kernel is compiled with the
.Dv EXEC_ELF32
or
.Dv EXEC_ELF64
options enabled, kernels which include
.Dv COMPAT_SVR4
should also typically include
.Dv EXEC_ELF32
(for 32-bit ELF support)
and/or
.Dv EXEC_ELF64
(for 64-bit ELF support).
.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
.Nx
system. This directory
is named /emul/svr4. Any file operations done by SVR4 programs
run under
.Nx
will look in this directory first. So, if a SVR4
program opens, for example, /etc/passwd,
.Nx
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
.Nx
counterparts. Shared
libraries should also be installed in the shadow tree.
.Pp
The simplest way to setup your system for SVR4 binaries is:

.Bl -tag -width 123 -compact
.It 1.
Make the necessary directories:
.Pp
.Bl -tag -width 123 -compact -offset indent
.It (me@netbsd) mkdir -p /emul/svr4/{dev,etc}
.br
.It (me@netbsd) mkdir -p /emul/svr4/usr/{bin,lib}
.br
.It (me@netbsd) 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 netbsd '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 netbsd '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@netbsd) cd /usr/share/examples/emul/svr4/etc
.br
.It (me@netbsd) cp netconfig nsswitch.conf /emul/svr4/etc
.br
.It (me@netbsd) cp SVR4_MAKEDEV /emul/svr4/dev
.br
.It (me@netbsd) cd /emul/svr4/dev; sh 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.
.Sh BUGS
Many system calls are still not emulated. The streams emulation is
incomplete (socketpair does not work yet).
.Pp
Most SVR4 executables can not handle directory offset cookies > 32
bits. More recent ones, compiled for large file support (Solaris 2.6
and up) can. With older programs, you will see the message "svr4_getdents:
dir offset too large for emulated program" when this happens. Currently,
this can only happen on NFS mounted filesystems, mounted from servers
that return offsets with information in the upper 32 bits. These errors
should rarely happen, but can be avoided by mounting this filesystem with
offset translation enabled. See the
.Fl X
option to
.Xr mount_nfs 8 .
The
.Fl 2
option to
.Xr mount_nfs 8
will also have the desired effect, but is less preferable.