Remote operations -- need for advice

[Roger Olson]

Monday, June 21, 2004 4:00 AM "Alexander Yaworsky" <yaworsky at migusoft.ru>
Wrote:
> I'm thinking how to implement CreateRemoteThread and besides fix memory
management functions.
> The complete (afaik) list includes:
> RtlCreateUserThread
> NtAllocateVirtualMemory
> NtFreeVirtualMemory
> NtProtectVirtualMemory
> NtQueryVirtualMemory
> NtLockVirtualMemory (do nothing?)
> NtUnlockVirtualMemory (do nothing?)
> NtFlushVirtualMemory
> NtMapViewOfSection
> NtUnmapViewOfSection
>
> Suggested implementation.
> Let's add two groups of handlers to the wineserver, something like
remote_operation_xxxx
> and remote_operation_xxxx_complete.
> remote_operation should do the following:
> 1) suspend_for_ptrace();
> 2) inject a piece of code into required process and start its execution;
> 3) resume_after_ptrace();
> 4) place calling thread into suspended state (or into some wait state?)
>
> remote_operation_complete should prepare reply and resume thread suspended
by remote_operation.
> Injected code should call required function and then
remote_operation_complete
> in context of required process.
> The question is: how to correctly get address of function?
> imho possible solutions are:
> 1) assume ntdll loaded at the same address for all processes -- 
unreliable;
> 2) get dll base address from per-process dll list and parse ELF by hand -- 
too complicated (?);
> 3) pass relative offsets and add them later to the ntdll's base address -- 
unreliable
>     a bit: ntdll may be replaced, although, it is unlikely;
> 4) extend the struct process (server/process.h) and the request
init_process with
>     pointers to required functions -- most reliable and simple but looks
ugly.
> What do you think?
>
Mike Hearn has a couple of suggestions here:
http://www.winehq.org/hypermail/wine-devel/2004/05/0164.html
I have a VB6 app (United Devices Agent) that requires this api in order to
function correctly
and have been attempting to learn C for the past month or so and starting to
get a handle on it
but I have a lot to learn about posix and signaling yet and generally how
things work.  If you
need or would like a volunteer to help test and troubleshoot using an actual
app, my hand is
up :-).  Meantime, I'm continuing to try to learn how all this works

Thanks, Roger