New compat_bsdos.8 Manpage

[Dan Plassche <dplassche%gmail.com@localhost>]

Hello,

After recent discussion on the port-amd64 mailing list and some bug fixes this
year, I would like to propose the new manpage below to document the working
compatibility with BSDi binaries under NetBSD on i386 and amd64.

An additional manpage covering the other 4.3-4.4 BSD derived binaries that work
on NetBSD under COMPAT_NOMID might also be helpful in the future.  I would be
interested in continuing to work on compat documentation.


Thanks,

Dan Plassche


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

NAME
     compat_bsdos -- binary compatibility for BSDi releases

DESCRIPTION
     The COMPAT_NOMID kernel option provides compatibility with BSDi 1-3
     a.out(5) binaries on NetBSD/i386 and NetBSD/amd64.	 The option is
     included in the GENERIC kernel on i386, but needs to be enabled along
     with EXEC_AOUT on amd64.

     Null memory protection must be disabled with the sysctl(7) option
     vm.user_va0_disable set to 0 for the binaries to run successfully.

     BSD/OS 2.0+ binaries also require an ldconfig(8) configuration or a sym-
     bolic link pointing to the /emul/bsdos/shlib directory to run outside of
     a chroot.

     BSD/OS 4.0 switched to elf binaries that do not run under the compatibil-
     ity layers currently available on NetBSD.

SEE ALSO
     options(4), a.out(5), elf(5), sysctl(7), compat_netbsd32(8)

HISTORY
     BSD/OS (BSD/386) 1.0-1.1 was derived from 4.3BSD-Reno code in the Net/2
     release.

     BSD/OS 2.0 was based on 4.4BSD-Lite, but introduced new static shared
     libraries compiled into binary objects under /shlib.  The build system
     included the shlicc command with the -Bstatic flag that allowed reverting
     to the standard library archive format.

     OpenBSD 2.2-4.7 included a different compatibility implementation under
     the COMPAT_BSDOS kernel option.

BUGS
     BSD/OS compatibility was broken on NetBSD 5-6.

     BSD/OS added SPARC support with release 3.0, but the binaries are incor-
     rectly recognized and fail as sunos executables on NetBSD/sparc and
     NetBSD/sparc64.

NetBSD 9.0			August 27, 2020			    NetBSD 9.0



Source:

.\"
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.\" by Dan Plassche.
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.Dd August 27, 2020
.Dt compat_bsdos 8 amd64,i386,sparc,sparc64
.Os
.Sh NAME
.Nm compat_bsdos
.Nd binary compatibility for BSDi releases
.Sh DESCRIPTION
.Pp
The
.Cd COMPAT_NOMID
kernel option provides compatibility with BSDi 1-3
.Xr a.out 5
binaries on
.Tn Nx Ns /i386
and
.Tn Nx Ns /amd64 .
The option is included in the
.Li GENERIC
kernel on
.Em i386 ,
but needs to be enabled along with
.Cd EXEC_AOUT
on
.Em amd64 .
.Pp
Null memory protection must be disabled with the
.Xr sysctl 7
option
.Va vm.user_va0_disable
set to
.Li 0
for the binaries to run successfully.
.Pp
.Bsx 2.0+
binaries also require an
.Xr ldconfig 8
configuration or a symbolic link
pointing to the
.Pa /emul/bsdos/shlib
directory to run outside of a chroot.
.Pp
.Bsx 4.0
switched to elf binaries that do not run under the
compatibility layers currently available on
.Nx .
.Sh SEE ALSO
.Xr options 4 ,
.Xr a.out 5 ,
.Xr elf 5 ,
.Xr sysctl 7 ,
.Xr compat_netbsd32 8
.Sh HISTORY
.Pp
.Tn Bsx "(BSD/386)"
1.0-1.1 was derived from
.Bx 4.3 Reno
code in the
.Tn Net/2
release.
.Pp
.Bsx 2.0
was based on
.Bx 4.4 Lite ,
but introduced new static shared libraries
compiled into binary objects under
.Pa /shlib .
The build system included the
.Li shlicc
command with the
.Fl Bstatic
flag that allowed reverting to the standard
library archive format.
.Pp
.Ox 2.2-4.7
included a different compatibility implementation
under the
.Li COMPAT_BSDOS
kernel option.
.Sh BUGS
.Pp
.Bsx
compatibility was broken on
.Nx
5-6.
.Pp
.Bsx
added
.Tn SPARC
support with release 3.0,
but the binaries are incorrectly recognized
and fail as
.Li sunos
executables on
.Tn Nx Ns /sparc
and
.Tn Nx Ns /sparc64 .