The Design and Implementation of the Anykernel and Rump Kernels

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Request Arguments Response Description
handshake type (guest, success/fail
authenticated or
exec), name of
client program
syscall syscall number, return value, errno
syscall args
prefork none authentication
cookie
Establish or update a process context
in the rump kernel.
Execute a system call.
Establish a fork authentication
cookie.
Table 3.5:
Requests from the client to the kernel.
We created a communication protocol between the client and rump kernel which
supports interactions of the above type. The request types from the client to the
kernel are presented and explained in Table 3.5 and the requests from the kernel to
the client are presented and explained in Table 3.6.
Now that we know the communication protocol, we will compare the operations
executed in the regular case and in the rump remote client case side-by-side. The
first part of the comparison is in Table 3.7 and the second part is in Table 3.8.
3.12.5 Of Processes and Inheritance
The process context for a remote client is controlled by the rump kernel server and
the rump lwproc interfaces available for local clients (manual page rump lwproc.3
at A–23) cannot be used by remote clients. Whenever a client connects to a rump
kernel and performs a handshake, a new process context is created in the rump
kernel. All requests executed through the same connection are executed on the
same rump kernel process context.