Develop Reference

How to create a program that converts 1 dll file into another dll file?

So I want to make a mod installer that doesn't contain any game code but still installs the full modded dll. Everyone with the official game always starts with the same dll (written in C# and unity).
My initial idea was to decompile using ILspy (as we only have access to .dlls) and recompile but that doesn’t work (build errors). I have thought about using something like winMerge to save changes between .dlls but not 100% sure how to use it and my final idea is to convert the whole binary from storred file into a normal number and find the difference between the 2 files.
Anyone have any idead of whats the best way to go about this?

It been a while but i want to get back to how i solved this. I ended up making an installer that compares the different in hash (binary) between 2 binary files and creates a patch. Now this patch can then be applied in the installer itself to make the output dll! Here is the github if anyone is interested - https://github.com/dan771/Snowtopia-Mod-Installer

My best luck has come from ildasm / patch / ilasm. You can do essentially the same thing with Mono.Cecil. It's quite automatable even in the face of an obfuscated dll provided that the original dll has no native code.

Why are source code seen in exe as it is supposed to be binary?

Recently I did an experiment with one of my c# .NET compiled exe by renaming the extension to .txt.
When viewed in the Notepad, I was able to see all my source code in English Language which made me confused if I was looking at a .cs file or a .exe file.
After this event I realized that anyone who has this exe can copy all the codes an re-compile them into a clone with some hidden additional codes (or malwares) that could harm my reputation among users.
However I know a little about obfuscation which can rename all methods and properties into a non-human readable format, still I would like to ask here, isn't an exe program supposed to be (only) in a computer readable binary format (as I have learnt in school)? Why is there a need of obfuscation additionally? Is this problem only limited to exe which has a CLR header? Should I consider creating applications on other languages like C, if I want to make it hard to decompile?
Please Answer...
Edit:- Most of the codes can be seen in this area and I am unaware of what part of the source code it consists of.
Edt:- Also when I do the same with an exe that is compiled using Visual Foxpro (where Encrypted is checked in Project Properties), not even a single readable text is seen except some assembly infos. What encryption technique is used in it, can we use it (or like that) in dotnet (free or paid)?
Source - https://www.tek-tips.com/viewthread.cfm?qid=286147

How can I programmatically add content to new/existing executable using c# and possibly make the solution work on a mac?

I've seen a number of variations on this question and im not sure if this question has been completely duplicated.
I would like to be able to at run-time run an existing executable (SOURCE exe) and have it:
1) take an existing TARGET exe at run time and add content of any size and type to the TARGET exe (pdf, image, word, excel file type, etc)
2) be able to run the modified TARGET exe so that when the TARGET exe is run, it will find the embedded content inside of itself and copy the content to the hard drive and then run the program associated with the content (foe example, run excel on a copied xls file)
I've seen examples where you embed resources at compile time in visual studio but I want to do this at run-time in code (c#, java, whatever works). Either the host TARGET exe needs to already exist and content should be added to it OR the exe will need to be generated from scratch at run-time and content again added to it.
I also would prefer not to use any of the cmd-line tools that visual studio or any other tool would run behind the scenes (if possible) to create an exe to minimize the enduser needing to download any more libraries/sdks than necessary.
This product is in line with what i want to do
http://www.boomeranglistbuilder.com/instructions/usingsoftware.php
(I want to improve upon it) :)
Lastly it'd be great if the solution could be cross platform compatible (doubt it though)
Could this be done in java?
I've seen the window library resource method updateresource method mentioned in my searches but I'm not sure if that would completely fit my situation. can anyone comment?
I hope my question is clear. Please let me know.
Any help would be graciously appreciated.
Thank you,
Carlos

I think that it's true for most binary file formats (including the executables), appending data to a well-formed file will not affect the usage of the file, the way it is typically interpreted by most programs. You could, maybe, take advantage of this.
To embed, you'll need to take your (existing) target executable and simply append some binary data to it. That data will have two parts:
A magic word (to denote the presence of an appended resource)
The resource itself.
So, this:
[target executable data]
Becomes this:
[target executable data]
[magic word]
[resource]
To read the resource from the target executable, simply have that executable open itself, search for the magic word and, if it's present, start reading the resource appended after it.
This is what WinRAR does (or at least did four years ago, when I last checked) to recognize the archives inside of its self-extracting files.

How do I remove unnecessary resources from my project?

I am working with a very big project (a solution that contains 16 projects and each project contains about 100 files).
It is written in C++/C# with Visual Studio 2005.
One of the projects has around 2000 resources out of which only 400 are actually used.
How do I remove those unused resources?
I tried to accomplish the task by searching for used ones.
It worked and I was able to build the solution, but it broke at runtime.
I guess because enums are used. (IMPORTANT)
How can I make sure that it doesn't break at runtime?
EDIT:
I think one method could be to generate the resource (that is not found) on the fly at runtime (somehow).
But I have no idea about ... anything.
NOTE: It's okay if a few unnecessary resources are still there.

What I would do is write a custom tool to search your source code.
If you remove a resource ID from a header file (i.e. possibly called resource.h) and then recompile and get no warnings: then that's a good thing.
Here is how I would go about writing the app. Take as input the resource file (resource.h) you want to scrutinize. Open the header file (*.h) and parse all the resource constants (Or at least the onces you are interested in). Store those in a hash table for quick look up later.
For each code file in your project, search the text for instances of each of your resource ID's. When a resource ID is used, increment the value in the hash table otherwise leave it at zero.
At the end, dump all the resource ID's that are zero out a log file or something. Then test that indeed you can remove those specified resource ID's safely. Once you do that, then write another tool that removes the specified resource ID's given the results of your log file.
You could write such a tool in perl and it would execute in about 0.3 seconds: But would take days to debug. :)
Or you could write this in .NET, and it would execute a little slower, but would take you an hour to debug. :)

You can use third party plug-in for Visual Studio as ReSharper. This add-in will analyze your C# code and point out unused resources. But it only works with C#.

For C++ projects, check out The ResOrg from Riverblade.
"The Resource ID Organiser (ResOrg for short) is an Add-in for Visual C++ designed to help overcome one of the most annoying (and unnecessary) chores of developing/maintaining Windows applications - maintaining resource symbol ID values"
http://www.riverblade.co.uk/products/resorg/index.html

I've never had one that bad. My method in compiled programs is to use a REXX script which emulates GREP looking for references to source that I suspect is not being used, remove them from the program and see what breaks. I use the REXX script because I can pre-filter the list of files I want to search. Which allows me to do a search across folders and computers.

If your code contains dynamic loading of resources (e.g. via strings) at runtime, then there is no way to automatically determine which resources can be safely removed from the source. A dynamic loading statement could load any resource.
Your best bet is to start with your trimmed down version of the app, run it, and identify which resources are missing when you test it. Then add them back in and retest.

You may want to take a look at the tool Reflector (free), not to be confused with ReSharper (expensive). It can show you which DLLs are dependent on another. Then if you want you may be able to remove the DLL that is not being referenced by anything else. Watch out if you are using dependency injection or reflection which then could break your code without your knowledge.
Reflector:
http://www.red-gate.com/products/reflector/.
This add-in draws assembly dependency graphs and IL graphs:
http://reflectoraddins.codeplex.com/Wiki/View.aspx?title=Graph.

In the "Resources View" of the Solution Explorer, right-click and select "Resource Symbols". Now you get a list where you can see which resources constants are used in the .RC-file. This help you might be a bit on the way to cleanup your Resource.h (although it does not show you which resources are not used in the actual C++ code).

Maybe Find Unused Resources in a .NET Solution helps here? Basically, you'll have to check which resources are used (e.g. by comprehensive code coverage checks) and remove the unused ones.
And probably you should not be afraid by using the trail-and-error approach to cleaning up.

In the Solution Explorer, right click and on a Reference and click on the menu item Find Dependent Code.
If it can't find any dependent code then you can remove this reference from the project. (The Remove operation is also under the right-click menu.)
EDIT: For a large project, the Find Dependent Code operation will take a long time. So since you have 2000 resources and most likely value your time this probably is not a viable option....

For C++ resources, did you try right-clicking the project in "Resource View" and then deleting the ones which do not have a tick mark next to them? It is unsafe to delete unused dialog resources since they are referenced as "enum"s in code (like the following).
enum { IDD = IDD_ABOUTBOX };
..however for all the others it should be safe.

How To Store Files In An EXE

Alright, so I'm working on programming my own installer in C#, and what I'd like to do is something along the lines of put the files in the .exe, so I can do
File.Copy(file, filedir);
Or, if this isn't possible, is there another way of doing what I am attempting to do?

I wouldn't code my own installer, but if you truely want to embed files into your assembly you could use strongly typed resources. In the properties dialog of your project open up the "Resources" tab and then add your file. You'll then be able to get the file using:
ProjectNamespace.Properties.Resources.MyFile
Then you'll be able to write the embedded resource to disk using:
System.IO.File.WriteAllBytes(#"C:\MyFile.bin", ProjectNamespace.Properties.Resources.MyFile);

Honestly, I would suggest you NOT create your own installer. There are many many issues with creating installers. Even the big installer makers don't make their own actual installers anymore, they just create custom MSI packages.
Use Mirosoft Installer (MSI). It's the right thing to do. Make your own custom front-end for it, but don't recreate the already very complex wheel that exists.
UPDATE: If you're just doing this for learning, then I would shy away from thinking of it as "an installer". You might be tempted to take your "research" and use it someday, and frankly, that's how we end up with so many problems when new versions of Windows come out. People create their own wheels with assumptions that aren't valid.
What you're really trying to do is called "packaging", and you really have to become intimately familiar with the Executable PE format, because you're talking about changing the structure of the PE image on disk.
You can simulate it, to a point, with putting files in resources, but that's not really what installers, or self-extractors do.
Here's a link to Self-Extractor tutorial, but it's not in C#.
I don't know enough about the .NET PE requirements to know if you can do this in with a managed code executable or not.
UPDATE2: This is probably more of what you're looking for, it embeds files in the resource, but as I said, it's not really the way professional installers or self-extractors do it. I think there are various limitations on what you can embed as resources. But here's the like to a Self-Extractor Demo written in C#.

I'm guessing here, but if you are trying to store resources in your application before compilation, you can in the Project Explorer, right click a file you would like to add, chose properties and change the type to Embedded Resource.
You can then access the embedded resources later by using the instructions from this KB:
http://support.microsoft.com/kb/319292

in case you simply want to store multiple files in a single file storage (and extract files from there, interact etc.) you might also want to check out NFileStorage, a .net file storage. written in 100% .NET C# with all sources included. It also comes with a command line interpreter that allows interaction from the command line.