Disassemby of Code

[Barry Margolin]

In article <79645363.0307250800.17ab1c99@posting.google.com >,
vrk1981 <vrk1981@yahoo.com> wrote:

>Is there a tool (Linux or Solaris) that can be used to get the disassembled code
>corresponding to the C executable code (a.out) that GNU compiler (gcc)
>produces.

What does "man -k disassembler" show? It should list "dis" on Solaris.

--
Barry Margolin, [email]barry.margolin@level3.com[/email]
Level(3), Woburn, MA
*** DON'T SEND TECHNICAL QUESTIONS DIRECTLY TO ME, post them to newsgroups.
Please DON'T copy followups to me -- I'll assume it wasn't posted to the group.

[David Medeiros]

objdump will show you the disassembled code.

objdump --source --disassemble <executable file name>

you can also do a
man objdump



"vrk1981" <vrk1981@yahoo.com> wrote in message
news:79645363.0307250800.17ab1c99@posting.google.c om...

> Dear Sir/Madam,
>
> Is there a tool (Linux or Solaris) that can be used to get the

disassembled code

> corresponding to the C executable code (a.out) that GNU compiler (gcc)
> produces.
>
> Thank you for your time.
>
> Regards,
> Ramakrishnan.V

[vrk1981]

Dear Sir,

I tried it in both linux and solaris and got the following
======
$ man odjdump
No manual entry for odjdump
=========

Thanks,
Ramakrishnan.V

"David Medeiros" <dmedeiros@broadbus.com> wrote in message news:<cc539f7ed1c305f6bc4c5923096b445b@free.terane ws.com>...

> objdump will show you the disassembled code.
>
> objdump --source --disassemble <executable file name>
>
> you can also do a
> man objdump
>
>
>
> "vrk1981" <vrk1981@yahoo.com> wrote in message
> news:79645363.0307250800.17ab1c99@posting.google.c om...

> > Dear Sir/Madam,
> >
> > Is there a tool (Linux or Solaris) that can be used to get the

> disassembled code

> > corresponding to the C executable code (a.out) that GNU compiler (gcc)
> > produces.
> >
> > Thank you for your time.
> >
> > Regards,
> > Ramakrishnan.V

[Binary]

To begin with, I answered your original post on comp.lang.c, don't crosspost
if you get an answer.

You will need your development packages then, if you cannot find objdump. I
told you (in comp.lang.c) to use objdump with the -D switch. What is your
Linux distribution? On Redhat you will have to install the binutils rpm I
believe, on Slackware, go into the D packages section, and find the
development binaries.

"vrk1981" <vrk1981@yahoo.com> wrote in message
news:79645363.0307251641.7b28f2e6@posting.google.c om...

> Dear Sir,
>
> I tried it in both linux and solaris and got the following
> ======
> $ man odjdump
> No manual entry for odjdump
> =========
>
> Thanks,
> Ramakrishnan.V
>
> "David Medeiros" <dmedeiros@broadbus.com> wrote in message

news:<cc539f7ed1c305f6bc4c5923096b445b@free.terane ws.com>...

> > objdump will show you the disassembled code.
> >
> > objdump --source --disassemble <executable file name>
> >
> > you can also do a
> > man objdump
> >
> >
> >
> > "vrk1981" <vrk1981@yahoo.com> wrote in message
> > news:79645363.0307250800.17ab1c99@posting.google.c om...

> > > Dear Sir/Madam,
> > >
> > > Is there a tool (Linux or Solaris) that can be used to get the

> > disassembled code

> > > corresponding to the C executable code (a.out) that GNU compiler (gcc)
> > > produces.
> > >
> > > Thank you for your time.
> > >
> > > Regards,
> > > Ramakrishnan.V

[vrk1981]

Dear Sir,

Yes it lists "dis".

i tried "dis a.out" and got a huge Assembly kanguage cide for a simlple C code!

Just curious to know if we can get the source ( .c ) fine too!

Thanks
Ramakrishnan.V



Barry Margolin <barry.margolin@level3.com> wrote in message news:<R7dUa.397$0z4.371@news.level3.com>...

> In article <79645363.0307250800.17ab1c99@posting.google.com >,
> vrk1981 <vrk1981@yahoo.com> wrote:

> >Is there a tool (Linux or Solaris) that can be used to get the disassembled code
> >corresponding to the C executable code (a.out) that GNU compiler (gcc)
> >produces.

>
> What does "man -k disassembler" show? It should list "dis" on Solaris.

[Artie Gold]

vrk1981 wrote:

> Dear Sir,
>
> I tried it in both linux and solaris and got the following
> ======
> $ man odjdump
> No manual entry for odjdump

That's objdump, not odjdump.

--ag

> =========
>
> Thanks,
> Ramakrishnan.V
>
> "David Medeiros" <dmedeiros@broadbus.com> wrote in message news:<cc539f7ed1c305f6bc4c5923096b445b@free.terane ws.com>...
>

>>objdump will show you the disassembled code.
>>
>> objdump --source --disassemble <executable file name>
>>
>>you can also do a
>> man objdump
>>
>>
>>
>>"vrk1981" <vrk1981@yahoo.com> wrote in message
>>news:79645363.0307250800.17ab1c99@posting.google .com...
>>

>>>Dear Sir/Madam,
>>>
>>>Is there a tool (Linux or Solaris) that can be used to get the

>>
>> disassembled code
>>

>>>corresponding to the C executable code (a.out) that GNU compiler (gcc)
>>>produces.
>>>

If you're looking for the original source code, forget it; do a google
serach on `decompilation C' to see why.

HTH,
--ag


--
Artie Gold -- Austin, Texas

[Kurtis D. Rader]

On Fri, 25 Jul 2003 17:46:30 +0000, vrk1981 wrote:

> i tried "dis a.out" and got a huge Assembly kanguage cide for a simlple C
> code!
>
> Just curious to know if we can get the source ( .c ) fine too!

Of course not. The CPU executes "opcodes". Those opcodes, in
general, correspond to very simple operations; for example, adding two
numbers. There is no way to convert from a stream of machine opcodes
to statements in the C language (or any "high level" language for that
matter). What the dis(1) and objdump(1) commands do is convert the
numeric opcodes to assembly language statements. Those statements are
a close approximation of the assembly language code emitted by the C
compiler. A given statement in C can result zero, one, or many assembly
statements (i.e., machine opcodes).

If none of the above makes any sense you need to learn how to program
in assembly language (as opposed to C) for your system. Then it will
make sense :-)

[David Schwartz]

"vrk1981" <vrk1981@yahoo.com> wrote in message
news:79645363.0307251646.7c691968@posting.google.c om...

> i tried "dis a.out" and got a huge Assembly kanguage cide for a simlple C

code!

You asked for the disassembled code corresponding to that source code.
For "simple C code" that's going to be a huge assembly language program.

> Just curious to know if we can get the source ( .c ) fine too!

Then you're not talking about disassembling, you're talking about
decompiling!

DS

[Greg P.]

"David Schwartz" <davids@webmaster.com> wrote in message
news:bfv1c8$6if$1@nntp.webmaster.com...

> You asked for the disassembled code corresponding to that source code.
> For "simple C code" that's going to be a huge assembly language program.

Something that (when I was naive), I tried many, many times to create...all
ending up as unfinished projects. I don't think any program (that's free or
relatively small) can parse the mangled-assembly code from objdump (and the
like) and form a proper C source file. I know that one exists for Java (as I
have it), but Java compiles into a different format (bytecode). If you want
to learn ASM and create C from it, good luck and let me know =)

[Kenny McCormack]

In article <6n1Va.1492$Bg.209@newsread4.news.pas.earthlink.ne t>,
Greg P. <no@spam.sam> wrote:

>"David Schwartz" <davids@webmaster.com> wrote in message
>news:bfv1c8$6if$1@nntp.webmaster.com...

>> You asked for the disassembled code corresponding to that source
>> code. For "simple C code" that's going to be a huge assembly
>> language program.

>
>Something that (when I was naive), I tried many, many times to
>create...all ending up as unfinished projects. I don't think
>any program (that's free or relatively small) can parse the
>mangled-assembly code from objdump (and the like) and form a proper C
>source file. I know that one exists for Java (as I have it), but Java
>compiles into a different format (bytecode). If you want to learn ASM
>and create C from it, good luck and let me know =)

This is interesting. I think I've had much the same experience as you;
that is, I think it ought to be possible to convert the output of
a disassembler into compilable C code (not, of course, into the original
C code, complete with comments, or even into anything remotely
human-readable, but merely to something that can be compiled and run).

However, I've never been able to do it.

At a minimum, it ought to be possible to convert it into a compilable .S
file, but even that is apparently easier said than done.

[David Schwartz]

"Kenny McCormack" <gazelle@yin.interaccess.com> wrote in message
news:bg440u$1ni$1@yin.interaccess.com...

> >Something that (when I was naive), I tried many, many times to
> >create...all ending up as unfinished projects. I don't think
> >any program (that's free or relatively small) can parse the
> >mangled-assembly code from objdump (and the like) and form a proper C
> >source file. I know that one exists for Java (as I have it), but Java
> >compiles into a different format (bytecode). If you want to learn ASM
> >and create C from it, good luck and let me know =)

> This is interesting. I think I've had much the same experience as you;
> that is, I think it ought to be possible to convert the output of
> a disassembler into compilable C code (not, of course, into the original
> C code, complete with comments, or even into anything remotely
> human-readable, but merely to something that can be compiled and run).

> However, I've never been able to do it.

> At a minimum, it ought to be possible to convert it into a compilable .S
> file, but even that is apparently easier said than done.

There are programs that do this. It's not particularly difficult. If I
had more time right now, I'd dig up a reference for you.

DS

[Greg P.]

"David Schwartz" <davids@webmaster.com> wrote in message
news:bg47sd$9j7$1@nntp.webmaster.com...

> There are programs that do this. It's not particularly difficult. If I
> had more time right now, I'd dig up a reference for you.

I know that this newsgroup is pretty much a GPL-mindset (in terms of
licenses), but imagine what would happen if such decompilation programs
(from exe to asm to c) became widespread. I don't care much for
closed-source, proprietary coders or programs, but I'm sure that some
companies would get a bit unnerved! Hehe! =)

[Barry Margolin]

In article <ZXhVa.1444$mr1.938@newsread3.news.pas.earthlink.n et>,
Greg P. <no@spam.sam> wrote:

>"David Schwartz" <davids@webmaster.com> wrote in message
>news:bg47sd$9j7$1@nntp.webmaster.com...

>> There are programs that do this. It's not particularly difficult. If I
>> had more time right now, I'd dig up a reference for you.

>
>I know that this newsgroup is pretty much a GPL-mindset (in terms of
>licenses), but imagine what would happen if such decompilation programs
>(from exe to asm to c) became widespread. I don't care much for
>closed-source, proprietary coders or programs, but I'm sure that some
>companies would get a bit unnerved! Hehe! =)

Why? The resulting C code won't look anything like what they originally
wrote. It doesn't have any more information than the binary code that was
used to generate it, it's just a little "prettier".

--
Barry Margolin, [email]barry.margolin@level3.com[/email]
Level(3), Woburn, MA
*** DON'T SEND TECHNICAL QUESTIONS DIRECTLY TO ME, post them to newsgroups.
Please DON'T copy followups to me -- I'll assume it wasn't posted to the group.

[Rich Teer]

On Mon, 28 Jul 2003, Greg P. wrote:

> I know that this newsgroup is pretty much a GPL-mindset (in terms of
> licenses), but imagine what would happen if such decompilation programs

YOu must be confusing us with comp.linux.programmer. :-)

> (from exe to asm to c) became widespread. I don't care much for
> closed-source, proprietary coders or programs, but I'm sure that some
> companies would get a bit unnerved! Hehe! =)

So why are you using M$ Outhouse to post?

--
Rich Teer, SCNA, SCSA

President,
Rite Online Inc.

Voice: +1 (250) 979-1638
URL: [url]http://www.rite-online.net[/url]

[Greg P.]

"Rich Teer" <rich.teer@rite-group.com> wrote in message
news:Pine.GSO.4.44.0307281640500.11592-100000@zaphod.rite-group.com...

> On Mon, 28 Jul 2003, Greg P. wrote:
> YOu must be confusing us with comp.linux.programmer. :-)

Your statement is sorta true. I do believe that most peeps here are happy
with GNU-based licenses though...opposed to strict UNIX ones =)

> So why are you using M$ Outhouse to post?

If I could pick my choice of ng readers I would, but the office does not
allow =(

[David Schwartz]

"Greg P." <no@spam.sam> wrote in message
news:ZXhVa.1444$mr1.938@newsread3.news.pas.earthli nk.net...

> "David Schwartz" <davids@webmaster.com> wrote in message
> news:bg47sd$9j7$1@nntp.webmaster.com...

> > There are programs that do this. It's not particularly difficult. If

I

> > had more time right now, I'd dig up a reference for you.

> I know that this newsgroup is pretty much a GPL-mindset (in terms of
> licenses), but imagine what would happen if such decompilation programs
> (from exe to asm to c) became widespread. I don't care much for
> closed-source, proprietary coders or programs, but I'm sure that some
> companies would get a bit unnerved! Hehe! =)

The decompiled program conveys little more useful information than the
disassembled one.

DS

[dmills@spamblock.demon.co.uk]

Greg P. <no@spam.sam> wrote:

> I know that this newsgroup is pretty much a GPL-mindset (in terms of
> licenses), but imagine what would happen if such decompilation programs
> (from exe to asm to c) became widespread. I don't care much for
> closed-source, proprietary coders or programs, but I'm sure that some
> companies would get a bit unnerved! Hehe! =)

I seem to recall an incident involving some form of 'compiled' basic a few
years back (possibly an early version of visual basic) where it was
discovered that the the 'compiled executable' was really just the interpreter
with the source code concatinated onto the end of the executable.

IIRC red faces were the result, but I just remember noticing this in
story in passing so some of the details may be wrong.

Regards, Dan.
--
** The email address *IS* valid, do NOT remove the spamblock
And on the evening of the first day the lord said...........
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