stack

[jt]

hello everyone..

int fun()
{
/* anything */
}
int main(void)
{
fun();
}

in this program, when the control is transferred to function fun()..
the return address is pushed to the stack..
Is it possible to access this value..??

[Bartc]

"Chris Torek" <no****@torek.n etwrote in message
news:g7******** @news3.newsguy. com...

In article
<38************ *************** *******@v1g2000 pra.googlegroup s.com>
jt <ka**********@g mail.comwrote:

>>hello everyone..

int fun()
{
/* anything */
}
int main(void)
{
fun();
}

in this program, when the control is transferred to function fun()..
the return address is pushed to the stack..

Actually, it is put in the register "lr" (PPC), "ra" (MIPS), "%o7"
(SPARC), or 14 (IBM S/390; spelled %r14 in GNU assembler). As
others have noted, if fun() is expanded in line, there is no control
transfer at all. But on the VAX and PDP-11, it is indeed placed
on the (hardware) stack.

You left out x86-32. A little-used processor, I know...

--
Bartc

[Harold Aptroot]

"jt" <ka**********@g mail.comwrote in message
news:38******** *************** ***********@v1g 2000pra.googleg roups.com...

hello everyone..

int fun()
{
/* anything */
}
int main(void)
{
fun();
}

in this program, when the control is transferred to function fun()..
the return address is pushed to the stack..
Is it possible to access this value..??

We've had a lot of "not in standard C" responses now.. what use are they?

Your compiler may have the intrinsic function _ReturnAddress( ) (and/or
_AddressOfRetur nAddress() ) available
You can also try to access 'the address of the last argument + its size' as
though it was a pointer-sized thing but that's less stable and very
implementation dependand

[santosh]

Harold Aptroot wrote:

"jt" <ka**********@g mail.comwrote in message

news:38******** *************** ***********@v1g 2000pra.googleg roups.com...

>hello everyone..

int fun()
{
/* anything */
}
int main(void)
{
fun();
}

in this program, when the control is transferred to function fun()..
the return address is pushed to the stack..
Is it possible to access this value..??

We've had a lot of "not in standard C" responses now.. what use are
they?

If they manage to redirect the OP to a more suitable forum, then IMO,
they served their purpose.

Your compiler may have the intrinsic function _ReturnAddress( ) (and/or
_AddressOfRetur nAddress() ) available

Which compiler has the latter function (just curious)?

You can also try to access 'the address of the last argument + its
size' as though it was a pointer-sized thing but that's less stable
and very implementation dependand

This is probably the worst method (if once could call it that) that I've
seen so far.

The return address is a feature of the *implementation * , which in the
vast majority of cases uses features of the underlying processor to
accomplish this. Thus for a robust solution to the OP's problem, one
needs to determine the details of the implementation and the underlying
hardware.

[Johannes Bauer]

jacob navia schrieb:

Of course it is. Most viruses do.
But we will not tell you how.

No. Most viruses don't. Many worms do.

Regards,
Johannes

--
"Wer etwas kritisiert muss es noch lange nicht selber besser können. Es
reicht zu wissen, daß andere es besser können und andere es auch
besser machen um einen Vergleich zu bringen." - Wolfgang Gerber
in de.sci.electron ics <47************ ***********@new s.freenet.de>

[MisterE]

Is it possible to access this value..??

No.

[Harold Aptroot]

"santosh" <sa*********@gm ail.comwrote in message
news:g7******** **@registered.m otzarella.org.. .

Harold Aptroot wrote:

>"jt" <ka**********@g mail.comwrote in message

news:38******** *************** ***********@v1g 2000pra.googleg roups.com...

>>hello everyone..

int fun()
{
/* anything */
}
int main(void)
{
fun();
}

in this program, when the control is transferred to function fun()..
the return address is pushed to the stack..
Is it possible to access this value..??

We've had a lot of "not in standard C" responses now.. what use are
they?

If they manage to redirect the OP to a more suitable forum, then IMO,
they served their purpose.

And the OP still wouldn't know anything
Which is great, because most people in clc are just here to flame people who
ask questions that in their opinion don't belong there - without answering
them first.

>

>Your compiler may have the intrinsic function _ReturnAddress( ) (and/or
_AddressOfRetu rnAddress() ) available

Which compiler has the latter function (just curious)?

Some versions of MSVC

>You can also try to access 'the address of the last argument + its
size' as though it was a pointer-sized thing but that's less stable
and very implementation dependand

This is probably the worst method (if once could call it that) that I've
seen so far.

It's very bad
I've seen it work though, and that's all that really matters (most virusses
are platform specific anyway)

The return address is a feature of the *implementation * , which in the
vast majority of cases uses features of the underlying processor to
accomplish this. Thus for a robust solution to the OP's problem, one
needs to determine the details of the implementation and the underlying
hardware.

Or just assume it'll be the most common implementation and let the OP
complain when that assumption turns out to be false?

An other solution that will not sit well with C-purists but should work:
inline assembly!

[Harold Aptroot]

"MisterE" <Mi*****@nimga. comwrote in message
news:48******** *************** @news.optusnet. com.au...

>

>Is it possible to access this value..??

No.

Of course it is
The OP did not request a standard compliant way to do it after all

[Eric Sosman]

Harold Aptroot wrote:

"santosh" <sa*********@gm ail.comwrote in message
news:g7******** **@registered.m otzarella.org.. .

>Harold Aptroot wrote:

>>"jt" <ka**********@g mail.comwrote in message

news:38******* *************** ************@v1 g2000pra.google groups.com...

>>>hello everyone..

int fun()
{
/* anything */
}
int main(void)
{
fun();
}

in this program, when the control is transferred to function fun()..
the return address is pushed to the stack..
Is it possible to access this value..??

We've had a lot of "not in standard C" responses now.. what use are
they?

If they manage to redirect the OP to a more suitable forum, then IMO,
they served their purpose.

And the OP still wouldn't know anything

The O.P. has learned that his problem cannot be solved
with unaided C. The O.P. has also been directed to a place
where he might learn more.

Look at it this way: When you conduct a Google search you
do not receive information about the subject you searched for.
Rather, you receive a whole bunch of pointers to other places
that might provide information. Since Google gives the searcher
only links but no actual data, do you consider Google useless?

Which is great, because most people in clc are just here to flame people
who ask questions that in their opinion don't belong there - without
answering them first.

I think not. There are some who visit this newsgroup for
nothing more (it seems) than the sheer joy of polluting; they
have found their way into my killfile. But my killfile for this
group has only (checks) four entries, so I take issue with your
use of "most" and suggest "some" as an alternative.

[...]
An other solution that will not sit well with C-purists but should work:
inline assembly!

Still better would be inline COBOL, which at least has
a "C" in it.

--
Eric Sosman
es*****@ieee-dot-org.invalid

[Keith Thompson]

"Harold Aptroot" <ha************ @gmail.comwrite s:

"santosh" <sa*********@gm ail.comwrote in message
news:g7******** **@registered.m otzarella.org.. .

>Harold Aptroot wrote:

[...]

>>We've had a lot of "not in standard C" responses now.. what use are
they?

If they manage to redirect the OP to a more suitable forum, then IMO,
they served their purpose.

And the OP still wouldn't know anything

[...]

Nonsense. The OP has already gotten the best answer we can give him
with regard to the C language, that it provides no portable way to get
the return address. He's far more likely to get a *useful* answer
that will help him do what he wants to do by posting to a more
suitable forum.

As for the multiplicity of answers saying essentially the same thing,
that's a consequence of the fact that Usenet is asynchronous; several
people post answers before seeing the others. There's no easy
solution to this in an unmoderated newsgroup. (I note that
comp.lang.c.mod erated has even more of a problem with multiple similar
answers than comp.lang.c does, because of long latency and the
moderator's choice not to reject duplicate answers.)

--
Keith Thompson (The_Other_Keit h) ks***@mib.org <http://www.ghoti.net/~kst>
Nokia
"We must do something. This is something. Therefore, we must do this."
-- Antony Jay and Jonathan Lynn, "Yes Minister"

[CBFalconer]

jt wrote:

>
int fun() {
/* anything */
}
int main(void) {
fun();
}

in this program, when the control is transferred to function fun()..
the return address is pushed to the stack..
Is it possible to access this value..??

In a machine that can execute the standard C language, there is no
need for a stack. This makes it hard to access a return address
(of unknown form) stored in a non-existant stack.

--
[mail]: Chuck F (cbfalconer at maineline dot net)
[page]: <http://cbfalconer.home .att.net>
Try the download section.