COMPAT_SVR4(8)          NetBSD System Manager's Manual          COMPAT_SVR4(8)

NNAAMMEE
     ccoommppaatt__ssvvrr44 - setup procedure for running SVR4/iBCS2 binaries

DDEESSCCRRIIPPTTIIOONN
     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
     or depend on:

           kernel internal data structures
           the /proc filesystem
           the pty subsystem
           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 includ-
     ed only if the kernel is compiled with the EXEC_ELF32 or EXEC_ELF64 op-
     tions 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).

     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 in-
     stall 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 setup 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}
                (me@netbsd) mkdir -p /emul/svr4/usr/openwin/{bin,lib}

     2.   Copy files from an svr4 system:

                (me@svr4) cd /usr/lib
                (me@svr4) tar -cf - . | \
                     rsh netbsd 'cd /emul/svr4/usr/lib; 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 -'

     3.   Setup 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; ./SVR4_MAKEDEV all


     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.

BBUUGGSS
     Many system calls are still not emulated. The streams emulation is incom-
     plete (socketpair does not work yet).

     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 re-
     turn 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 --XX option to mount_nfs(8).  The --22 option to
     mount_nfs(8) will also have the desired effect, but is less preferable.

NetBSD                           July 6, 1996                                2