Subject: COMPAT_DARWIN status
To: None <>
From: Emmanuel Dreyfus <>
List: tech-kern
Date: 12/13/2002 08:11:13
In the guts of COMPAT_DARWIN:

We now have a fairly good emulation for CLI based Darwin programs on the
powerpc. I have been able to use Darwin's ls, sh, telnet (the kerberized
version, it loads more than 25 libraries), and vi. 

Now the goal is to produce some graphic display. I learnt that the
equivalent of the X11 server is called WindowServer. This process knows
the detail of the graphic boards handling, and it provides drawing
capability to other programs. Processes talk to WindowServer using Mach
messages, I don't now yet how WindowServer talks to the hardware.

On startup, WindowServer attemps to register its ports so that other
processes can reach it. There is a nameserver process that associate
service names to Mach ports. It is called a mach_init. mach_init is the
first process started on Darwin, it even forks UNIX init(8) (we won't
emulate this, of course).

So now the goal is to startup mach_init, and to make registration with
it possible. In order to use that, we must have a working Mach message
implementation (from now, we support only message from userland to
kernel, not from kernel to userland). This is the next task. 

Help is welcome. Manpower is scarce, especially in the following areas:
- Write MD bits for alpha (to use threads in COMPAT_OSF1) (should be
- bring i386 up ot date (hard...)
- Writing test programs for COMPAT_MACH (easy but time consuming)

And now the updated roadmap:

To do:
- Find volounteers
- cleanup COMPAT_MACH from Darwin specific bits
- machine dependent bits on alpha to use Mach multithreading for
- bring i386 up to date
- complete multithreading and semaphore support
- siginfo

In progress:
- Mach messages

- Basic semaphore support
- Basic mutlithreading support
- Signal handling
- Mach traps support in ktrace
- Debug mach traps quick and dirty emulation to get dynamic linking
- Even more accurate stack layout on startup
- Emulate enough of BSD system calls to get dynamic linking
- implement required mach traps on powerpc
- accurate stack layout on startup
- reverse engineering mach traps
- enough support for in native gdb to trace mach-O bins
- mach traps support on i386 and powerpc
- Mach-O binaries suport

Emmanuel Dreyfus.  
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