I am new to TCL and trying to dig the C code that runs TCL commands , I installed TCL in windows . Not able to find the C code .
Can anyone suggest me where can I get the C code ? or any links ?
For browsing, see here on core.tcl.tk which is a web view into the code repository. The directories you're most likely to want to look inside are generic (platform-independent code, most of Tcl) and win (Windows-platform code, build instructions). The other main directories there are unix (Unix-specific sources), mac (Mac-specific build system), library (Tcl library files; no C code) and doc (documentation in a format that you've probably never encountered before).
For code relating to a specific version of Tcl, see the Tcl file distribution area on SourceForge. Pick your version, download the exact sources you want. Note that they'll be laid out in virtually the same way as in the repository: look in generic and win to see the C code.
You are new to Tcl and yet, you go for the C source code already? What is your goal? Are you trying to learn Tcl, or learn C? Any way, the source can be found here:
http://tcl.sourceforge.net/
Related
I am currently trying to solve a reversing challenge, where c code is compiled for a 32bit linux system.
To solve this challenge I am trying to make use of ghidra but am faced with a few issues. A bit of a summary what I have done up to this point:
I have two OS available to me, one 64bit Linux System on my Laptop and this 64bit Windows 10. Apparantly the programm was compiled with gcc without a -g option making ghidra fail to debug the programm. Manually debugging it with gdb in Terminal is possible but terrible to use (at least for me).
So all I can do is look at the assembler code in the CodeBrowser of Ghidra and its respective decomipled c code. With that I got to understand that some of the instructions are decrypted during the runtime of the programm and in order to further analyse the code, I want to be able to execute parts of the instructions to slowly but surely decrypt and understand the hidden parts of the programm.
That being said, the only issue here is that I do not know how I can do that. I have noticed that ghidra has the ability to run java code, but all the examples I looked at that were provided by ghidra allow me to only patch hardcoded instructions into the programm but not to actually execute/evaluate them.
My specific issue at hand is following part of the programm (green marked part):
Ghidra has all the knowledge it needs to execute this part and I just do not know how to do that. I could of cause do it by hand, but that is just boring and not really why I am doing these challenges and that is the same reason as why I am not looking for finished scripts that unpack this programm for me but for a way to execute my analysis.
Finally to summarize my question: I am asking for a way to execute the green marked decrypting part of the targeted programm in ghidra without starting the debugger (since the ghidra debugger keeps failing on me).
I think you are mixing up a few things here. You say:
the programm was compiled with gcc without a -g option making ghidra fail to debug the programm
The debug information added with -g makes it easier to analyze and debug a program because you have information that would have otherwise have to be recovered by reverse engineering. This should not have an influence on whether you can run the program under a debugger in the first place, and as you noted running it with gdb in the terminal works. The Ghidra debugger basically just runs gdb in the background and attaches to it to exchange information, so it should work.
You have a few options now:
1. Get the Ghidra Debugger to run with this binary
Whatever issue you are encountering with the Ghidra debugger is probably a valid question for https://reverseengineering.stackexchange.com/
From then on you can pursue your initial plan to solve this via debugging.
2. Write a GhidraScript to reimplement the decryption
Understand the basic idea of what you recognized correctly as some kind of decryption loop. Then you can use one of Ghidra's scripting options[0] to write a simple script that reimplements this decryption, but writes the decrypted values to the Ghidra memory directly.
Any scripting language will obviously include basic arithmetic operations like + -, and xor and loops, and the Ghidra API provides the functions byte getByte(Address address) and setByte(Address address, byte value). If you encounter any issues or API questions while writing this script that will also be a valid follow up question for the RE Stack Exchange.
This approach has the advantage that you can then statically analyse the resulting data inside Ghidra again, e.g. disassemble the resulting code.
[0] Ghidra natively supports Python 2.7 and Java based Scripts and a rudimentary Python REPL, but there are other options like Jupyter and Script based Kotlin or Ruby, Kotlin and Clojure Scripts
I think this is more of a Tcl configuration question rather than a Tcl coding question...
I inherited a whole series of Tcl scripts that are used within a simulation tool that my company built in-house. In my scripts, I'm finding numerous instances where there are function calls to functions that don't seem to be declared anywhere. How can I trace the path to these phantom functions?
For example, rather than use source, someone build a custom include function that they named INCLUDE. Tclsh obviously balks when I try to run it there, but with my simulation software, it runs fine.
I've tried grep-ing through the entire simulation software for INCLUDE, but I'm not having any luck. Are there any other obvious locations outside the simulation software where a Tcl function might be defined?
The possibilities:
Within your software. (you have checked for this).
Within some other package included by the software.
Check and see if the environment variable TCLLIBPATH is set.
Also check and see if the simulation software sets TCLLIBPATH.
This will be a list of directories to search for Tcl packages, and you
will need to search the packages that are located outside of the
main source tree.
Another possibility is that the locations are specified in the pkgIndex.tcl file.
Check any pkgIndex.tcl files and look for locations outside the main source tree.
Within an unknown command handler. This could be in
your software or within some other package. You should be able to find
some code that processes the INCLUDE statement.
Within a binary package. These are shared libraries that are loaded
by Tcl. If this is the case, there should be some C code used to
build the shared library that can be searched.
Since you say there are numerous instances of unknown functions, my first
guess is that you have
not found all the directories where packages are loaded from. But an
''unknown'' command handler is also a possibility.
Edit:
One more possibility I forgot. Check and see if your software sets the auto_path variable. Check any directories added to the auto_path for
other packages.
This isn't a great answer for you, but I suspect it is the best you're going to get...
The procedure could be defined in a great many places. Your best bet for finding it is to use a tool like findstr (on Windows) or grep -R (on POSIX platforms) to search across all the relevant source files. But that still might not help! It might not be a procedure but instead a general command, which could be implemented in C and not as a procedure, or it could be defined in a packaged application archive (which are usually awkward to look inside). There are also other types of script-implemented command too, which could make things awkward. Generally searching and investigating is your best bet, but it might not work.
Tcl doesn't really differentiate strongly between different types of command except in some introspection operations. If you're lucky, you could find that info body tells you the definition of the procedure (and info args and info default tell you about the arguments) but that won't help with other command types at all. Tcl 8.7 will include a command (info cmdtype) that would help a lot with narrowing down what to do next, but that's no use to you now and it definitely doesn't exist in older versions.
How to use the C++ files generated by the Chisel compiler? the documentations are not clear on this, is there any other source to point me to it? I am really clueless on this, specially that I don't know C++.
Say for example for a simple adder circuit Adder.scala I will get the following files related to the emulator:
Adder.cpp, Adder.h, Adder-emulator.cpp, emul_api.h, emulator.h and sim_api.h.
For which I can compile by running
g++ Adder.cpp Adder-emulator.cpp
This generates the output a.out running this in the terminal generates three more files that I have no clue what they are.
00003710.cmd, 00003710.in and 00003710.out.
The C++ code is used to build an emulation of your design. You need to also define a tester that will drive the emulation, using poke() to set signal values, and peek() or expect() to read them.
You should not be compiling the C++ yourself. If you pass the --genHarness and --test options to Chisel, it will compile the C++ code, build the emulation and run your tester to drive it.
Have a look at the chisel-tutorial code for examples of this process.
I am trying to run a piece of code that includes "itkScalarImageTextureCalculator.h". However, cmake cannot find this reference, and I can't seem to find it manually neighter. I've looked for it in
Modules/Numerics/Statistics/include
Modules/Compatibility/V3Compatibility/include
Modules/Compatibility/Deprecated/include
but i can't find it anywhere. A search in the itk folder also returns no results. Was this library deleted/renamed/moved somewhere else? Or maybe there is some kind of problem with my itk installation? I have successfuly used other libraries, and I only have itk installed (I mean I don't have vtk, tcl etc).
It has been renamed itkScalarImageToTextureFeaturesFilter (probably in ITK 4.0). You can see this conversion listed in the table here: http://itk.org/Wiki/Proposals:Refactoring_Statistics_Framework_2007_Migration_Users_Guide
I'm trying to make a starpack like single binary which wrapped a bunch of tcl scripts inside. I looked at the TclApp doc from ActiveTcl, it seems like you have to use their basekit (e.g. /usr/local/ActiveTcl/bin/base-tk8.5-thread-linux-ix86). However, I have built the interpreter into my own binary. How to make my binary a basekit?
I'd start by asking whether it is really necessary to have your own build of Tcl. If you can structure your code so your custom pieces are loadable extensions (linked correctly against the stub library) then you can just use it with a standard kit distribution.
But if your code is such that it really needs to be built as the main executable, you can do what you're after. You probably want to start from Kitgen, which is both maintained and reasonably open. You'll have to do some work to make things assemble correctly; in particular, make sure your code is built with static linking against any external libraries it needs (with the exception of the C library and other things that can reasonably be assumed to be present on the target platform) as the runtime link environment of a kit-based distribution of Tcl is distinctly weird. Building as a stubbed extension (which you can just store inside the kit package) is much simpler to get right.