|
> Date: Sun, 21 Feb 2010 07:28:01 -0500 > From: zlinuxman@wowway.com > To: debian-user@lists.debian.org > Subject: Re: Decompiler? > > On Sun, 21 Feb 2010 05:06:21 -0500 (EST), Hadi Motamedi wrote: > > > > Dear All > > > > I have disassembled the object file on my Debian server , by the following : > > > > #objdump wmain > > > > In the output , I have recognized the intended subroutine that I need to > > find the exact command syntax that it sends out. To this end, I asked > > you guys on how to capture it through 'tcpdump' but didn't success. I > > read this segment assembly language code but it is somewhat difficult to > > decode. Can you please let me know what Debian decompiler is suitable for > > this case? I tried with 'decompyle' but it didn't get through. > > First, let me make sure I understand what yo u are asking. You have some > binary object code and you want to transform it back into the C source > code that it came from. Is that right? Or did I misunderstand you? > > If that is what you want, then I doubt that it is possible. I've never > heard of a decompiler. I have heard of a disassembler, but even they > have their limitations. I myself have done extensive work as a programmer > on a disassembler for the s390 platform. It happens to be the disassembler > resident in the TRACK for z/VM freeware program. So I am speaking from > experience here. Even a disassembler is a guess. Here are some things that > you lose, even in a disassembler: > > 1. All comments. > 2. The names of all variables > 3. The distinction between code and data > > For example, if I encounter the hex string '41101004' that could be a > > LA 1,4(,1) > > instruction. But it might not be an instruction. It might be data. It > might be > > DC F'1091571716' > > Or maybe it's a floating point number in traditional s390 hexadecimal > floating point format. Or maybe it's part of an escape sequence of codes > to be sent to a printer. You can never be sure. All these uncertainties > are present in a disassembler. In assembly language, there is pretty much > a one-to-one correspondence between assembler instructions and machine > instructions. But in a high-level language, that is not so. A single > statement in source code may generate a long sequence of machine instructions. > How do you know where one statement ends and another begins? > > In short, I doubt if it is possible. Even if you do find something that > purports to be a decompiler, its output will almost certainly not match > the original input. Compilation is a one-way process. > > ; > > -- > To UNSUBSCRIBE, email to debian-user-REQUEST@lists.debian.org > with a subject of "unsubscribe". Trouble? Contact listmaster@lists.debian.org > Archive: http://lists.debian.org/[🔎] 1425884921.13942331266755281555.JavaMail.root@md01.wow.synacor.com > Thank you for your reply . Actually my Debian server is running an application program that sends commands toward an attached network element . The commands deal with 'profile read' , 'profile modify' , and 'profile delete' issues . On the application gui , there is an option to try for 'profile replace' that I cannot find the related command . As there is a need to try for this 'profile replace' in batch file , so I need to find the exact command syntax for this purpose . I tried to capture it through tracing with 'tcpdump' but it was un-successful . So I dis-assembled the code and I was lucky to find the related subroutine . It is short in length but I cannot decode it to find the logic in behind . So I need to find a de-compiler to de-compile it to some sort of higher level languages to see if I can understand the login behind . Please give me a hint on how to accomplish this . Hotmail: Trusted email with Microsoft’s powerful SPAM protection. Sign up now. |