[MPlayer-dev-eng] state of realvideo?
mplayer at outflux.net
Mon May 20 22:26:13 CEST 2002
On Mon, May 20, 2002 at 07:30:43PM +0200, Arpi wrote:
> > How do you see which are or are not parameters? Also, digging through the
> i can't see, just feel.
> reverse engineering is not an 1:1 transformation :)
Heh. Okay, I just wanted to make sure I wasn't missing something obvious.
> imho, ebp-X is reference to the local variables (structs, arrays can be
> big), the parameters are referenced by ebp+X
Hmmm. I'll have to check this...
Exported fn(): return_int_take_two_alloc_four
:0804830a 55 push ebp
:0804830b 89e5 mov ebp, esp
:0804830d 83ec18 sub esp, 18
:08048310 c7450811a10000 movl ptr [ebp+8], a111
:08048317 c7450c22a20000 movl ptr [ebp], a222
:0804831e c745e800b00000 movl ptr [ebp-24], b000
:08048325 c745ec01b00000 movl ptr [ebp-20], b001
:0804832c c745f002b00000 movl ptr [ebp-16], b002
:08048333 c745f403b00000 movl ptr [ebp-12], b003
:0804833a b8efbe0000 mov eax, beef
:0804833f c9 leave
:08048340 c3 ret
:08048341 90 nop
yup! You're right. the 'a...' values I assigned to args, and the 'b...'
values I assigned to stack vars. And it's hopeless to find the return
value, since it's in eax, which means it'll only be obvious if it gets set
RIGHT before a return like here.
Oh good, that makes me much less nervous about figuring this API out.
Whatever compiler they used is _weird_. All over the place it does stuff
:00001ec0 53 push ebx
:00001ec1 e800000000 call 00001ec6
:00001ec6 5b pop ebx
:00001ec7 81c34ac40200 add ebx, 2c44a
freaks me out. :) Although, it doesn't seem to use ebx ever. Whatever,
probably just goofy compilerisms.
> dunno, i've never hacked c++ code.
> we just can hope that the actualplugins don't use c++ stuff, if they do, it
> will make our life REALLY HARD.
Well, the .so's have an undefined reference, like I said, to
__pure_virtual. And everything points to it being a C++ shared library
except for the fact that there appears to be no "access" method to the
class. So very weird. I will continue like it's not C++.
Is there any way to solve the "__pure_virtual" reference? Just defining
it in my loader doesn't work: I have to make a stub in a separate .so
file. Really strange...
Kees Cook @outflux.net
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