The Design and Implementation of the Anykernel and Rump Kernels

170
Host syscall
rump syscall
1. open("/dev/null", O_RDWR) 1. rump_sys_open("/dev/null",
O_RDWR) is called
2. libc executes the syscall trap. 2. librumpclient marshalls the arguments
and sends a“syscall”request
over the communication socket.
the calling thread is suspended until
the system call returns.
3. syscall trap handler calls
sys_open()
3. rump kernel receives syscall request
and uses a thread associated
with the process to handle request
4. thread is scheduled, determines
that sys_open() needs to be
called, and proceeds to call it.
4. pathname lookup routine calls
copyinstr()
5. pathname lookup routine needs
the path string and calls
copyinstr() which sends a
copyinstr request to the client
6. client receives copyinstr request
and responds with string datum
7. kernel server receives a response to
its copyinstr request and copies the
string datum to a local buffer
Table 3.7:
part 1/2.
Step-by-step comparison of host and rump kernel syscalls,