Delphi 5 debugger is working!

[Kuba Ober]

On Tuesday 23 August 2005 20:05, Vitaliy Margolen wrote:
> As of todays CVS Delphi 5 debugger is fixed.
>
> Well, ok, there are still some bugs. One is a minor bug (Module view
> reports all modules as a project executable name), but all exports are
> there. You can even try to disassemble them. But here is where the major
> problems start. Debugger segfaults on that. This is because
> NtQueryVirtualMemory and
> NtProtectVirtualMemory currently don't work on other processes.

What are the problems with implementing those using SIGSTOP/SIGCONT and 
ptrace(2)? I imagine that for example changing memory protection for another 
process could be achieved as follows:

1. SIGSTOP to the process
2. inject code that invokes mprotect() and stops execution
3. change EIP, ESP, etc. then SIGCONT
4. wait(pid,&status,WUNTRACED) on the child
5. remove the injected code, restore registers, SIGCONT

I have never implemented such a beast so I might be way off, nevertheless it'd 
be interesting to hear what the problems are. phrack might also be a useful 
read in that respect.

Cheers, Kuba