Frankenlibc is an experimental build tool to make writing applications against rump kernels easier, and to unify code.

There are known and unknown bugs!

build with "make", or with "./build.sh" for additional options.

Frankenlibc provides a small libc that is enough to let the fiber-based librumpuser library run natively on your platform without any system libraries. It combines this library, the rump kernel, and NetBSD's libc into a single libc that you can just use to link against applications to make them run against a rump kernel rather than the host.

Currently there are three userspace implementations included, NetBSD, Linux and FreeBSD, and one very basic baremetal implementation, qemu-arm. The currently supported and tested architecture/OS combinations are: Linux x86_64, i386, arm, powerpc64, mips, NetBSD x86_64, i386, arm, FreeBSD x86_64, i386. There is work in progress support for powerpc, aarch64 and riscv64. Both arm and mips work with hard and soft float. Powerpc64 supports the v1 ELF ABI only at present, arm is EABI only, and mips is o32 ABI only. Additional implementations and architectures will be added soon.

There is also an option to build a deterministic version with no random numbers and a fake clock, so runs are completely repeatable.

There is a wrapper called rexec ("rump exec") that can pass in files, block devices and tap devices as network devices, and will also run the program in a seccomp sandbox on Linux or under Capsicum on FreeBSD. These are pretty aggressive, eg open cannot be called, but you may want to add further sandboxing in addition.

A compiler wrapper is generated in rump/bin to compile your own programs, which works out the best method to wrap the compiler. Essentially you just need to use the include files, libc and other libraries and crt files in the rump/ output directory. For gcc a spec file is used, while many clang installations can use a sysroot, although eg NetBSD's linker does not support sysroot. For most systems a line like the following will work if you do not use the wrapper:

gcc -nostdinc -Irump/include -Lrump/lib -Brump/lib -o rumpobj/tests/hello -static tests/hello.c

A number of NetBSD system tools are built as part of the build, named with the rump. prefix eg rump.ls, rump.ifconfig, rump.newfs, rump.tar to allow simple tests and file system manipulation.