The buildrump.sh script builds unmodified NetBSD kernel drivers such as file systems and the TCP/IP stack as components for hosts such as Linux and other BSDs. These components can be linked in a variety of configurations to form rump kernels, which provide services to applications directly on the host. The benefits of this approach include avoiding the overhead of OS virtualization. Also, root privileges are not mandated.

An example use case is fs-utils which uses rump kernels to access file system images. For more information on rump kernels, see http://www.NetBSD.org/docs/rump/

See also the wiki for a short-term TODO list.

Clone the repository and run:

• ./buildrump.sh checkout fullbuild

You will now find the kernel drivers and necessary headers in ./rump ready for use. Examples on how to use the resulting drivers are available in the tests and examples directories.

It is not necessary to read this document further unless you are interested in details.

The checkout command above will fetch the necessary subset of the NetBSD source tree from anoncvs.netbsd.org into ./src. You are also free to use any other method for fetching NetBSD sources, though the only officially supported way is to let the script handle the checkout.

The script will then proceed to build the necessary set of tools for building rump kernels, e.g. the BSD version of make, after which it will build the rump kernels. By default, cc from path is used along with other host tools such as nm. Crosscompilation is documented further below.

If the command tests or fullbuild is given, the script will run simple tests to check that e.g. file systems and the TCP/IP stack work correctly. If everything was successfully completed, the final output is:

[...]
rump kernel halting...
syncing disks... done
unmounting file systems...
unmounted kernfs on /kern type kernfs
unmounted rumpfs on / type rumpfs
unmounting done
halted
Done

Success
$ 

To learn more about command line parameters, run the buildrump.sh script with the -h flag.

If the environment variable $CC is set, its value is used as the compiler instead of cc. This allows not only to select between compiling with gcc or clang, but also allows to specify a crosscompiler. If $CC is set and does not contain the value cc, gcc, or clang the script assumes a crosscompiler and will use tools with names based on the target of $CC with the format target-tool (e.g. target-nm).

Crosscompiling for an ARM system might look like this (first command is purely informational):

$ arm-linux-gnueabihf-gcc -dumpmachine
arm-linux-gnueabihf
$ env CC=arm-linux-gnueabihf-gcc ./buildrump.sh [params]

Since the target is arm-linux-gnueabihf, arm-linux-gnueabihf-nm etc. must be found from $PATH. The assumption is that the crosscompiler can find the target platform headers and libraries which are required for building the hypervisor.

Some operating systems provide rump kernels as a package:

• Arch Linux
• Void Linux

The toolchain in PATH is used to produce the target binaries (support for cross-compilation may be added at a later date). The script builds other necessary tools out of the NetBSD source tree using build.sh. In addition from what is expected to be present on a bare-bones host (sh, rm, etc.), the following software is required during the build process:

• cc (gcc and clang are known to work)
• ld (GNU or Solaris ld required)
• binutils (ar, nm, objcopy)
• zlib (not used, but wanted by NetBSD tools/compat/configure)
• cvs (required only for "checkout")

The following platforms have been tested:

• Linux

  • Linux Ubuntu-1210-quantal-64-minimal 3.5.0-18-generic #29-Ubuntu SMP Fri Oct 19 10:26:51 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux (with thanks to Zafer Aydogan for providing access, amd64)
  • Linux Gallifrey 2.6.35.14-106.fc14.x86_64 #1 SMP Wed Nov 23 13:07:52 UTC 2011 x86_64 x86_64 x86_64 GNU/Linux (with seLinux in permissive mode, amd64)
  • Linux vyrnwy 3.6.2-1.fc16.x86_64 #1 SMP Wed Oct 17 05:30:01 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux (Fedora release 16 with read-only /usr/src via NFS)
  • Linux golden-valley 3.2.27-18-ARCH+ #1 PREEMPT Fri Dec 21 14:18:42 UTC 2012 armv6l GNU/Linux (Arch, Raspberry Pi, evbarm)
  • Linux void-rpi 3.6.11_1 #1 PREEMPT Tue Feb 19 17:40:24 CET 2013 armv6l GNU/Linux (Void, Raspberry Pi, evbarm)

• DragonFly BSD

  • DragonFly 3.2-RELEASE DragonFly v3.2.1.9.g80b03f-RELEASE #2: Wed Oct 31 20:17:57 PDT 2012 root@pkgbox32.dragonflybsd.org:/usr/obj/build/home/justin/src/sys/GENERIC i386

• FreeBSD

  • FreeBSD frab 9.1-PRERELEASE FreeBSD 9.1-PRERELEASE #5 r243866: Wed Dec 5 02:15:02 CET 2012 root@vetinari:/usr/obj/usr/src/sys/RINCEWIND amd64 (static rump kernel components, with thanks to Philip for test host access)

• NetBSD

  • NetBSD pain-rustique.localhost 5.1_STABLE NetBSD 5.1_STABLE (PAIN-RUSTIQUE) #5: Wed Feb 16 13:34:14 CET 2011 pooka@pain-rustique.localhost:/objs/kobj.i386/PAIN-RUSTIQUE i386

• Solaris

  • SunOS hutcs 5.10 Generic_142900-15 sun4v sparc SUNW,T5240 Solaris (needs xpg4/bin/sh, sparc64 in 64bit mode, sparc in 32bit mode)
  • SunOS pkgsrc-dev 5.11 joyent_20120126T071347Z i86pc i386 i86pc (with thanks to Jonathan for test host access, amd64 in 64bit mode, i386 in 32bit mode)

There is also initial support for Cygwin, but it will not work out-of-the-box due to object format issues (ELF vs. PE-COFF). Mac OS X is likely to require support for its linker.