On Sat, 24 Aug 1996 19:36:08 +0200 (CED) 
 Krister Walfridsson <cato@df.lth.se> wrote:

 > I think I have found a bug in compat_sunos. If I understand the 
 > compat_sunos source, the little program below should try to run 
 > /emul/sunos/bin/as before it tries /bin/as. But it doesn't look
 > in /emul/sunos at all...
 > 
 > #include <stdio.h>
 > 
 > int
 > main(int argc, char *argv[])
 > {
 >   char *f = "/bin/as"; 
 >   
 >   execv(f, argv);
 >   fprintf(stderr, "Cannot exec %s\n", f);
 >   exit(1);
 > }

Hmm ... just looked ... sunos_sys_execv() (sunos_misc.c, syscall #11) does a 
check for the alternate path... However, in the SunOS syscalls.master, 
syscall #59 simply calls sys_execve(), and thus no alternate path will be 
checked.  Which syscall number is your program using?  (ktrace can tell 
you.) 

 > By the way... The sparc page on www.netbsd.org says that there should
 > be a compat_svr4 man page, but I doesn't have such a beast. Where can 
 > I find it?

Hmm, it appears to be in the source trunk, but not in the branch.  There 
are some other documentation changes that may be pulled up to the release 
sources; perhaps we can tack this one on to that list, and bug the RE 
about it.  In the mean time, I'll attch the manpage source below.

 -- save the ancient forests - http://www.bayarea.net/~thorpej/forest/ -- 
Jason R. Thorpe                                       thorpej@nas.nasa.gov
NASA Ames Research Center                               Home: 408.866.1912
NAS: M/S 258-6                                          Work: 415.604.0935
Moffett Field, CA 94035                                Pager: 415.428.6939

----- snip -----
.\"	$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 BSD 4
.Sh NAME
.Nm COMPAT_SVR4
.Nd setup procedure for running SVR4/iBCS2 binaries
.Sh DESCRIPTION
NetBSD 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?

The SVR4 compatibility feature is active
for kernels compiled with the
.Nm COMPAT_SVR4
option enabled.

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.
.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@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/src/etc/etc.svr4
.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; ./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.