I’m saying it would be more trouble than it’s worth, when there are plenty of
other tools fully designed for running executable code in a controlled
environment. Don’t let me stop you from trying it as a learning exercise,
though.
On Aug 4, 2019, at 5:07 PM, Derek Snider <derekbsnider@xxxxxxxxx> wrote:
Are you saying that it would be difficult to pre-stuff unicorn’s stack with
data, run some x86 code, and access the result from the stack?
Sent from my iPhone
On Aug 4, 2019, at 4:46 PM, Brian <lotharyx@xxxxxxxxx> wrote:
I could have it all wrong, but I suspect perhaps you have a skewed concept
of the purpose of Unicorn. Unicorn is a CPU emulator. It is not a virtual
machine. Unicorn lets you observe how a specific processor executes machine
instructions. It doesn’t care about anything outside the emulated processor
core. No peripherals, no interrupts, etc. Unicorn emulating an x86 CPU
doesn’t see a keyboard, or a video adapter, or a SATA interface, etc., so
there is nothing there to hook into. It is concerned only with CPU state as
it emulates machine instructions.
I suppose you could do something like what you described, but it seems like
an unnecessarily complicated way to approach a problem that already has many
functional and performant solutions. You’d have to write a lot of code to
provide the function of everything external to the emulated processor.
As an example of my point, I’m using Unicorn to analyze a firmware image for
an ARM Cortex-M processor. I’ve had to write a lot of supporting code to
allow analyzing the behavior of timer peripherals which the firmware expects
to be generating periodic interrupts.
Anyway, I hope maybe this helps give a clearer perspective of just what
Unicorn is.
Cheers,
-B
On Aug 4, 2019, at 4:25 PM, Derek Snider <derekbsnider@xxxxxxxxx> wrote:
Hmm, I was expecting that you'd be able to hook into calls of your choosing
for things like that.
One use case I can think of it for executing stored procedures in a
database. They could be compiled by TinyCC upon insertion, and executed in
place by Unicorn, operating upon the data provided to it.
On Sun, Aug 4, 2019 at 4:06 PM Brian <lotharyx@xxxxxxxxx> wrote:
What’s a use case for this? I’m having trouble imagining a broad-scope
application for an execution environment with absolutely no connection to
the world outside the emulator whatsoever. Want to send network packets?
You can’t. Want to write a line to the console? There isn’t one. etc....
-B
On Aug 4, 2019, at 3:35 PM, Derek Snider <derekbsnider@xxxxxxxxx> wrote:
Not exactly. It would be 100% pure compatible C (C99), so no mapping C
data structures back and forth between the the script language’s form. If
a C library exists, you could just link it in, and map the function
calls, nothing else. I know you could do this with CLING but it’s huge,
and requires basically the entirety of LLVM, and I doubt the result would
be as secure as using Unicorn-Engine.
So yes, it would be “yet another scripting language”, but it would
actually be C — real C, not just “C-like”, generating real x86 code, not
a high-level interpreted bytecode, and can “JIT” the exact same x86 code
it’s interpreting, and be safely running in the Unicorn engine sandbox,
etc.
I think it would be particularly useful, and probably run a heck of a lot
faster than any other “script language”, even ones with JIT.
Sent from my iPhone
On Aug 4, 2019, at 2:45 PM, farmdve <farmdve@xxxxxxxxx> wrote:
What you are describing is called a scripting language. You know what,
even Python fits your needs.
On Sun, 4 Aug 2019 at 18:54, Derek Snider <derekbsnider@xxxxxxxxx>
wrote:
I looked at that, but it wasn’t quite what I was looking for, I don’t
think it answered either of my questions.
Is anyone interested perhaps in combining something like “Tiny CC” and
Unicorn to make a sort of C language that is both secure and portable,
and fast enough to compile and execute on the fly if necessary, yet
still be safe (as opposed to actually directly executing compiled code)?
Sent from my iPhone
On Aug 3, 2019, at 1:26 PM, Unicorn Engine <unicorn.emu@xxxxxxxxx>
wrote:
You can find some docs from the homepage unicorn-engine.org.
For example code, see samples under samples/, or bindings/python/
On Sun, Aug 4, 2019, 01:16 Derek Snider <derekbsnider@xxxxxxxxx>
wrote:
Hello there,
This project looks super interesting, but the documentation and
examples are a little lacking.
Two questions:
1) Is there a simple, "Hello, world", type example somewhere?
(Ideally for Linux or MacOS)?
2) Is there a way to use GCC to generate code that can be executed by
Unicorn Engine? Like read in a raw .o file and execute it?
Thanks in advance,
-Derek
