NetBSD supports running SVR4/iBCS2 binaries. This code has been tested on i386 (with binaries from SCO OpenServer and XENIX), m68k (with binaries from AMIX) and sparc (with binaries from Solaris) systems. Most programs should work, but not ones that use or depend on:
kernel internal data structures
the ticotsord loopback RPC mechanism (NIS uses this)
sound and video interfaces
threads (ttsession uses threads)
the streams administrative driver
The SVR4 compatibility feature is active for kernels compiled with the
COMPAT_SVR4 option enabled. Since support for ELF executables is included only if the kernel is compiled with the
EXEC_ELF32 or
EXEC_ELF64 options enabled, kernels which include
COMPAT_SVR4 should also typically include
EXEC_ELF32 (for 32-bit ELF support) and/or
EXEC_ELF64 (for 64-bit ELF support).
Another compatibility feature is
COMPAT_SVR4_32, which allows the execution of 32-bit SVR4 binaries on a machine with a 64-bit kernel. This requires
EXEC_ELF32 and
COMPAT_NETBSD32 options as well as
COMPAT_SVR4. It is configured the same way as
COMPAT_SVR4 but uses the
/emul/svr4_32 directory instead of
/emul/svr4. But typically,
/emul/svr4_32 can be made to point to
/emul/svr4 if the operating system donating the libraries has support for both 32-bit and 64-bit binaries.
Execution of 32-bit SVR4 binaries on a machine with a 32-bit kernel uses
COMPAT_SVR4, not
COMPAT_SVR4_32.
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
NetBSD system. This directory is named
/emul/svr4. Any file operations done by SVR4 programs run under
NetBSD will look in this directory first. So, if a SVR4 program opens, for example,
/etc/passwd,
NetBSD 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
NetBSD counterparts. Shared libraries should also be installed in the shadow tree.
The simplest way to set up your system for SVR4 binaries is:
1.
Make the necessary directories:
(me@netbsd) mkdir -p /emul/svr4/{dev,etc}
(me@netbsd) mkdir -p /emul/svr4/usr/{bin,lib,ucblib}
(me@netbsd) mkdir -p /emul/svr4/usr/openwin/{bin,lib}
(me@netbsd) mkdir -p /emul/svr4/usr/dt/{bin,lib}
2.
Copy files from an svr4 system:
(me@svr4) tar -cf - . | \
rsh netbsd 'cd /emul/svr4/usr/lib && tar -xpf -'
(me@svr4) tar -cf - . | \
rsh netbsd 'cd /emul/svr4/usr/ucblib && tar -xpf -'
If you are running openwindows:
(me@svr4) cd /usr/openwin/lib
(me@svr4) tar -cf - . | \
rsh netbsd 'cd /emul/svr4/usr/openwin/lib && tar -xpf -'
(me@svr4) tar -cf - . | \
rsh netbsd 'cd /emul/svr4/usr/dt/lib && tar -xpf -'
3.
You will also probably need the timezone files from your Solaris system, otherwise emulated binaries will run on UTC time.
(me@netbsd) mkdir -p /emul/svr4/usr/share/lib/zoneinfo
(me@netbsd) mkdir -p /emul/svr4/etc/default
(me@svr4) cd /usr/share/lib/zoneinfo
(me@solaris) tar -cf -. | \
rsh netbsd 'cd /emul/svr4/usr/share/lib/zoneinfo &&
(me@netbsd) echo TZ=US/Pacific > /emul/svr4/etc/default/init
4.
Set up the configuration files and devices:
(me@netbsd) cd /usr/share/examples/emul/svr4/etc
(me@netbsd) cp netconfig nsswitch.conf /emul/svr4/etc
(me@netbsd) cp SVR4_MAKEDEV /emul/svr4/dev
(me@netbsd) cd /emul/svr4/dev && sh SVR4_MAKEDEV all
As the major number allocated for emulation of SVR4 devices may vary between
NetBSD platforms, the SVR4_MAKEDEV script uses the
uname(1) command to determine the architecture the devices nodes are being created for; this can be overridden by setting the
MACHINE environment variable accordingly.
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.