I need to use the debug command in Windows 64x for learning purposes. When I type the command debug in the cmd, I get the following message:
'debug' is not recognized as an internal or external command,
operable program or batch file.
As I understand from some previous posts that debug does not work in 64x systems. Is there any work around for this issue?
EDIT:
I am trying to write assembly code for learning. I am not allowed to use any other option for writing assembly code. I have to use DEBUG.
debug.exe is not available in any of the 64 bit windows versions. What are you trying to accomplish? One option for you may be gnu debug - http://www.sourceware.org/gdb/
I know this is an ancient thread, but others might have the same question.
In general to use legacy software, the CLEANEST way to do it is to use the build in Hyper-V. And then have PC-DOS 3.30 (or any suitable 16 or 32 bit OS) on that.
Make sure to use a DYNAMIC disk (vhdx). This allows the disk to be mounted in Windows simply by clicking the vhdx (when not in use by Hyper-V - no sharing), so this allows for simple transfers, without complex net-setup.
There are other alternatives such as DOSBOX, though to my experience their emulation have some bugs (e.g. on the ancient FCB-system - older than file-handles)
I know it's a very long answer, but I just saw your post now. Use the vDosPlus (http://www.vdosplus.org/) or vDos (https://www.vdos.info/) software to run 16-bit (MS-DOS) programs on Windows 64-bit.
Related
I tried to learn "Lena's reversing for newbies", when some trouble arise.
I start Pixtopian Book with ollyDbg, then try to have MessageBox with message about uregistered version.
Then i switch to OllyDbg, stop program executing and press "Alt+F9" for "Back to user mode" which stop the program after it exit from DLL.
But after this program does not work, it's frozen and does not respond to my actions.
If i turn off "Back to user mode" program normally work.
What's the problem? Can i try to use "Back to user mode" in IDA (uses WinDbg) or some other debugger and How i can do this? Can i repair it function in OllyDbg?
P.S. It's like the program stopped and didn't run after use "ALT+F9".
/Sorry for my English, i'm just learning ;-)/
First of all, Ollydbg is meant for 32 bit platform. It means that it will run only on a 32 bit OS and can only debug 32 bit apps.
In x64 Operating Systems (specifically Windows) there is a feature called compatibility mode that lets you run 32 bit apps. The 32 bit code is either run by emulation or natively (when the hardware itself implements the instruction set and then it is called x86-64).
So, when you try to run Ollydbg in a x64 environment it will run, but you will experience problems like the one you are facing. It occurs because Ollydbg is run in an emulation mode. Being a debugger it needs access to the registers and other system structures, which it is denied. What it can see is a virtual image of the system.
So the solution to the problem is using a Virtual Machine.
You would install a 32 bit OS in it and debug the app using Ollydbg. As far as Virtual Machines are concerned, I would recommend VMWare. You can use either the workstation or player version. The latter is free but does not support snapshots.
Other solutions are Virtual Box, Parallels Workstation and Microsoft Virtual PC.
The disadvantages of them are that Virtual Box does not support hardware breakpoints, Parallels Workstation is no longer supported as of 2014 and moreover there you would get a BSOD if you try to single step through FPU instructions. I have not tested Virtual PC though.
Note : Ollydbg does not supports x64 but its author is working on a x64 version.
I just learned how to update changes to the exe file for ollydby v 2.01e.
suppose I wished to change a jl command to a jmp; do this by clicking the executable modules button, choose the file and right click to view the file. then record the changes and save file. The saved file also has a backup in case something goes wrong.
I just did a thorough learning of the pixtopian file. When I downloaded
that tutorial I get the file pixtopian107.exe only. Since it didn't agree with the tutorial I investigated further. That file is an installation file. It produces a regular pixtopian.exe file which is the file you wish to play with.
I also noticed that in running the file it never enters the main module.
this is because of the TLS callback. right now I am trying to learn how
to overcome this which is how i came to this site in the first place.
I am using ollydbg vs2.01e very effectively.
Another thing, in vs 2.01e I am still trying to save changed data. Until I succeed I am recording the changes in the exe files using hex editor.
From my experience I can tell that this functionality won't work on Windows 7.
On Windows 7 64bit --> Won't work at all.
On Windows 7 32bit --> Will work partially, but only when using option "File>Attach" in OllyDbg.
For me, best solution was to use Windows XP 32bit, then it worked fine.
I must reverse a legacy windows (16-bit, NE exec) application that controls an old DAQ that I must interface somehow with upgraded hardware. I've been able to disassemble the exec using W32Dasm (and WindowsCodeBack as well, the only two from many that I've tried that have worked) but the resulting asm file contains too many lines. I'd like to use a debugger and set some breakpoints to restrict the work. Could you advise which is the right approach to debug a Win16 app in 32-bit times? A VM running Windows98 for example? Which Win16 debugger could I use?
Many thanks
IDA can disassemble Win16 programs as well (though not the free version), and it's much more convenient than plain dead listing.
As for debuggers, I would try to find the Win16 Turbo Debugger (TDW.EXE). There's also OpenWatcom, which even supports remote debugging (so you can run the program in a VM and the debugger UI on your desktop).
I have some customers/candidate who complained that my program doesn't work on their Windows 7 64 bit version (confirmed with screenshots). The errors were strange, for example:
in the trial version i am
getting a error message whenever i
click on \"mark\" \"delete\" \"help\".
error msg is: Access violation at
address 0046C978 in module
\'ideduper.exe.\' read of address
00000004
windows 7 ultimate 64bit. i7 920
#2.67GHz 9gb or ram
'Mark', 'delete' and 'help' are just standard TToolButton on TToolbar.
The other example is failing to get a thumbnail from IExtractImage.
I have told them to try Compatibility mode but still doesn't work.
The problem is when I tested it on Windows 7 HP 64-bit on my computer (which I've done it before released it actually) it just works fine! So I don't know what causing it
Do you have any advice ?Are different Windows package (home basic,premium,ultimate,etc) treating 32 bit prog differently ?Are the newer version of Delphis (I use 2006) more compatible with 64 bit Windows ? Do I need to wait until 64 bit compiler out?
Thanks in advance
Your best bet in my opinion is to add MadExcept or EurekaLog or something similar to your application and give it to the customer to try again. MadExcept will generate log with stack trace, which will give you a clearer view of what is happening there.
To answer 2nd part of the question, 32bit Delphi programs work fine on 64bit Windows 7. I think it's more likely you have some memory management problems and the customer just happens to stumble upon them while you don't. Use FastMM4 to track those down.
Your applications is trying to access an invalid pointer. Changing environment may surface issues that are hidden in others. Check your application, and use FastMM + JCL+JCVL/MadExcept/EurekaLog to get a detailed trace of the issue. Some Windows APIs may have some stricter call requisites under 7 and/or 64 bit, but we would have to know what your app actually cals.
A free alternative to MadExcept is JCL Debug stuff. However it is less thorough and doesn't include the cool dialog box to send the stack trace to you via email, or as a file you can attach and manually email.
MadExcept is worth the money, and it is free for non-commercial use. You could try it first on your own PC, observe its functionality, and be sure it functions the way you want, and then buy it.
If buying Delphi is worth it (and it is!) then buying mad Except is a no brainer. But if you insist on rolling your own, JCLDebug (part of jedi code library) is also pretty nice.
Give them a stripped down version of your app and see when the problem goes away. I am betting it is your code as I never had any problems with my (hundreds of) W7/64 clients.
I'd be willing to bet it's an issue in your code. The reason it's failing on your customer's machine and not yours is that your machine probably has the default Data Execution Protection (DEP) enabled (which is turned on only for essential Windows programs and services), while your customer's computer is actually using DEP as intended (turned on for all programs and services).
The default setting (which is compatible with older versions of Windows, like 95/98/ME), allows software to execute code from what should be data segments. The more strict setting won't allow this, and raises a system-level exception instead.
You can check the settings between the two by looking at System Properties. I'm not at a Win7 machine right now, but on WinXP you get there by right-clicking on My Computer, choosing Properties, clicking on Performance Options, and then selecting the "Data Execution Prevention" tab. Find it on Vista/Win7 by using the Help; search for Data Execution Protection.
The solution, as previous answers have told you, is to install MadExcept or EurekaLog. You can also get a free version as part of JEDI, in JCLDebug IIRC. I haven't used it, so I can't vouch for it personally. I've heard it's pretty good, though.
If you don't want to go that route, set a breakpoint somewhere in the startup portion of your app (make sure to build with debugging info turned on). Run your app until the breakpoint is hit, and then use the IDE's Search->Goto Address (which is disabled until the breakpoint is hit). Enter the address from the exception dialog (not the one that's almost all zeros, but the 0046C978 address, prefixed with $ to indicate it's in hex) as in $0046C978. You'll probably end up in the CPU window looking at assembly code, but you can usually pick out a line of Delphi code of some sort that can sometimes give you a place to start looking.
In addition to all previous suggestions, I'll add the difference in accessing Registry under WOW64 compared to Win32. If your application is accessing Registry to read or write some settings, you should be aware of this. First, take a look at this and this page in the MSDN. On this page you will find 2 flags that determine the access you get to Registry from 32- or 64-bit application. KEY_WOW64_64KEY is the one that you should use.
In any case, I agree with others about using madExcept (or any other similar tool) to be able to find the exact cause of your problems.
I recently received a 64-bit crash dump from a customer.
Our processes are all 32-bit, but the customer's machine is running x64 Server 2008.
Visual Studio (both 2008 and 2010 Express) is telling me that I have to use the 64-bit version of MSVSMON.EXE, which I can't because I don't have a 64-bit machine.
I'm pretty sure there's a way to do this in WinDbg, but I find WinDbg to be hostile.
Is there any way to debug a 64-bit dump on a 32-bit machine, preferably using Visual Studio?
You need to make sure that customer uses 32 bit tools (adplus or DebugDiag) to capture crash dumps for your 32 bit processes. Then you can use your 32 bit machine to debug the dumps.
Link
Though Isalamon's comment is technically correct, nobody would like to execute that as the stack trace is horrible.
Let your customer know that this is necessary, and hope that he/she cooperates.
If you are not familiar with dump analysis, Microsoft is always there for you, http://support.microsoft.com
I worked around the problem by using 32 bit task manager (C:\Windows\SysWOW64\Taskmgr.exe) to capture the dump.
I have gotten excellent results using the advice on switching to x86 mode using !wow64exts.sw as advised here:
http://blogs.msdn.com/b/ntdebugging/archive/2008/06/03/how-to-debug-wow64-applications.aspx
Same advice figures here:
http://blogs.msdn.com/b/msdnforum/archive/2010/03/14/how-do-i-switch-to-32bit-mode-when-i-use-windbg-to-debug-a-dump-of-a-32bit-application-running-on-an-x64-machine.aspx
And background and related commands over here:
http://msdn.microsoft.com/en-us/library/windows/desktop/aa384163(v=vs.85).aspx
Hope this serves as a compilation of decent inputs on this topic in addition to what already exists in this thread. Thanks.
Is it Userdump or kernel dump? It looks like you got the system dump. If that is the case, then you can take help of !wow64exts extension on windbg and can root cause the problem.
I agree with anwer you should get dmp file captured correctly, but recently did some experiments with this type of incorrectly captured dmp file. I used WinDbg to patch SOS.dll to remove the arch check. I'm not 100% sure if what I'm getting is valid, but at least some it appears so... https://chentiangemalc.wordpress.com/2015/04/17/experimental-use-of-64-bit-dump-of-32-bit-net-process-in-windbg/
I was wondering if anyone knew of a way to remotely debug the Linux kernel running under VMWare (and if so, if there's a way to do it in Windows since linux kind of scares me...). Both are x86. I know VMWare has support for this (I saw a post about remote debugging via gdb), but if there was a way to do it from Windows (i.e. Eclipse CDT or something) that'd be awesome.
Thanks!
-Robert
You're not going to debug the Linux kernel (particularly remotely) using anything but gdb with { kdb | kgdb } extensions in-kernel, unless you write your own debug hooks.
According to Linus, he would prefer if you do not use a kernel debugger, even on Linux. Good luck getting one to work from Windows :)
Granted, this posting is from several years ago. Maybe he has changed his mind since then???
There's a thread where someone got 95% of the way here: http://communities.vmware.com/thread/236251. The one part he's missing is that the source files can't be found, but CDT supports setting a source path different from the symbol file. A bit of messing around and it seems to be working (i.e. I can set breakpoints, see the entire address space, etc.)
I would recommend debugging one Linux VM from another linux VM, if you only have one machine running Windows available.
You're going to have enough difficulty just getting that working, without throwing in something that is as unsupported and untested as what you're currently asking for.