Beginner Software RE help, RAM Addresses, library loading, where to start? - unix

To start this off, I use OS X which is a UNIX based system.
I have beginner theoretical knowledge in C++ and would like to expand my knowledge by software reverse engineering. Every guide I get into seems to jump in half way and I seem to miss a giant gap of information required to start up. What my end goal is to successfully build a working dylib for any application. Where do i start with learning Ram addresses, how do they work, how are libraries loaded and what the actual hell do I start reading, what subject. Everything I've learned so far has a distinct start point, certain syntax but I just find everything uses terminology I don't understand. I find myself just branching off more and more because an article used a keyword I don't understand, I google it, the other one uses five I don't understand and I just get stuck. The application under question does not have changing memory addresses, but I would also like to learn how to compensate for it using offsets.
Where do I start?!

Before you get started with reverse engeneering you'll need more than a theoretical knowledge of the C language. Forget C++ for now, C is simpler and it's so low level that once you master it you'll understand how programs work under the hood. Get you a copy of The C Programming Language by Brian Kernighan and Dennis Ritchie and go through the whole book.
Once you feel confortable writting C programs get familiar with UNIX standards like POSIX and then move on to OS X specific stuff. The best resource for OS X programming is http://developer.apple.com. The link below explains how dynamic libraries work on OS X. Once you get a good understanding of C it will all make sense.
https://developer.apple.com/library/mac/documentation/DeveloperTools/Conceptual/DynamicLibraries/100-Articles/OverviewOfDynamicLibraries.html

Related

What does it mean if someone refers to something as BootStrap?

I hear the term "BootStrap" thrown around a lot, but I'm not really sure what it refers to. I know there is a bootstrap CSS, but what exactly does the term mean?
Literally, a bootstrap is a tab on the sides or back of boots that helps you to pull them on. Putting on your shoes or boots is usually the last step of getting dressed; similarly, in programming it's been applied to the initialization or start-up step of a program.
See also the Wikipedia entry for bootstrapping:
Bootstrapping or booting refers to a group of metaphors which refer to a self-sustaining process that proceeds without external help.
[.. in Software Loading] booting is the process of starting a computer, specifically in regards to starting its software. The process involves a chain of stages, in which at each stage a smaller simpler program loads and then executes the larger more complicated program of the next stage. It is in this sense that the computer "pulls itself up by its bootstraps", i.e. it improves itself by its own efforts
[.. in Software Development] bootstrapping can also refer to the development of successively more complex, faster programming environments. The simplest environment will be, perhaps, a very basic text editor (e.g., ed) and an assembler program. Using these tools, one can write a more complex text editor, and a simple compiler for a higher-level language and so on, until one can have a graphical IDE and an extremely high-level programming language.
A shoehorn is another means to help you don footwear but it's idiomatically come to mean cramming something into a tight space.
In computer science Bootstrap (or more commonly "Boot") generally refers to the setup/start/initialization step of a process. It can mean many things depending on the context: starting a physical machine, setting up variables and services for an application to use, or even laying the css groundwork for a website to implement.
Bootstrapping let you create your own most complex design by just minimal configuration, rather than develop it from the scratch.

What language to use when prototyping a small game

I am currently considering writing a small game. It is essentially a map where you can zoom out and in, and in certain places click on info boxes where, at some point, I hope to integrate minigames. Granted, game might be overstating it. Think of it as an interactive map. The theme is how mathematics can be applied in peoples every day life to raise awareness on the usefullness of mathematics.
The question is how I as fast as possible can make a reasonable prototype. If I recieve enough positive response on this I might try to code "the real thing" and use the prototype to obtain funding.
However, I am at a crossroad. I want something to work rather fast and have some C++ experience coding optimization problems, mainly in c-style. I am not convienced, though, that coding it in C++ is the fast way to obtain a prototype. Though I have some experience coding in C++, but have no experience in coding any sort of GUI.
As I see it there is a number of possibilites:
C++, possibly using some library, such as boost or ???.
Start out purely webbased, using e.g. HTML 5 and java.
Python
C#/.NET
Others, such as?
I have to admit I have little experience with anything besides C++ and the STL.
So my question to this wonderful forum is basically, is there a language that provides a significant advantage? Also, any additional insight or comments is more than welcome!
Python is a simpler language than C++, and for prototyping it will help you focus on the task at hand. You can use Pygame, a game library built on the excellent cross-platform SDL library. It provides 2D graphics, input, and audio mixing features. SDL is mainly a C library (and thus compatible with C++), and there are a number of very useful libraries that integrate with it:
SDL_image for loading images in various formats
SDL_ttf for rendering text using TrueType fonts
SDL_mixer for audio mixing
SDL_net for networking
SDL_gfx for graphics drawing primitives
So if you prototype in Python using Pygame, there is a reasonable chance you’ll be able to port what you make over to C++ with minimal hassle, if and when you choose to do so.
Possible options:
Go with what you know the best. Anything else will require a learning curve, which may be weeks to months long. If you're willing to take that road in order to make your prototype, then there are some really great tools available.
BlitzBasic is a good way to go, and is basically designed to be for games
I've done little games in Java using Slick2D - but you'll need good grounding in object-oriented coding to work effectively in Java. If you've got that from C++, then you can see a tech demo I built in Slick2D called Pedestrians. It's open source, and has demo videos here.
You might also ask your question on https://gamedev.stackexchange.com/ - a Q/A site dedicated to game programming

What is a good language to develop in for simple, yet customizable math programs?

I'm writing to ask for some guidance on choosing a language and course of action in learning programming. I apologize if this type of question is inappropriate for Cross Validated, please advise me to another forum if that is the case.
I've seen thread after thread with questions from newbies, asking, "What is the best language to start with?" and then it always starts a flame war or someone just answers, "There's no best language, it's best to pick one and start learning it." My question is a little bit more focused than that.
First off, I've been programming my whole life, in very limited capacities. My deepest training was in C++. Whilst in my EECS degree program, I resolved to never be a software developer because I couldn't stand not interacting with people for such long periods of time. Instead I realized I wanted to be a math teacher, and so that is the path I have taken.
But now that I'm well down that path, I've started to realize that perhaps I could develop my own software to help me in the classroom. If I want to demonstrate the Euclidean algorithm, what better way than to have a piece of software that breaks down the process? Students could run that software as part of their studies, and the advanced students might even develop programs for themselves. Or, with an Ipad in hand, why not have an app that lets students take their own attendance? It would certainly streamline some of the needs of classroom management.
There's obviously a lot of great stuff already out there for math, and for education, but I want a way to more directly create things specific to my lectures. If I'm teaching a specific way of calculating a percent, I want to create an app that aligns with my teaching style, not just another calculator app that requires the student to learn twice.
The most I use in class right now is iWork Numbers/Microsoft Excel for my stats class. Students can learn the basic statistical functions, and turn some of their data into graphs.
I have dabbled a bit with R, and used Maple in college. I've started the basic tutorials for OS X/iOS development and have actually made good progress making an OS X app that takes a text string, converts it to numbers, and performs encryption using modular addition and multiplication. I sometimes use Wolfram|Alpha to save myself some time in getting quick solutions to equations or base conversions. I know of MatLab, Mathematica, and recently people have been telling me to check into Python or Ruby. I also know basic HTML, and while it's forgotten now, learned Javascript and PERL in college.
If I keep on the path of Obj-C/Cocoa, I think it will have great benefits. Unfortunately, anything I produced for Mac would only be usable on a Mac, so it wouldn't be universal for all of my students. Perhaps then learning a web language would be better. Second, I'm wondering if the primary use is mathematical, then perhaps my time would be better spent learning Mathematica Programming Language, or R, or something based less on GUI and more on simple coding of algorithms, maybe Python or Ruby?
It seems that Mathematica already has a lot of demos for different math concepts, so why reinvent the wheel is also a question I have. I think overall, it would be good to have more control and design things the way I need. And then, if I do want to make an "Attendance" app or something else, I would already have the programming experience to more easily design something for my iPad or MacBook.
The related question to this is what is a good language to teach to my students? In his TED talk, Conrad Wolfram says one of the best ways to check the understanding of a student is have them write a program. But if Mathematica does the math virtually automatically for them, then I'm not sure that will get the deeper experience of working out logic for themselves, like you do when you're writing C, or a traditional procedural language.
I know that programming takes time to learn, but I also know that at this point, my goal is not to be able to make an app like "Tiny Wings." With the app store ease, some of my work may be an extra revenue stream, but I see myself as more of a hobbyist, and now teacher looking to software development specifically for its ability to help me demonstrate mathematical concepts.
I think I will push ahead with Obj-C/Cocoa for OSX/iOS, but if anyone has some better guidance regarding all of the other available stuff, it would be much appreciated. I don't think I would want to go fully to the web (I like apps), but perhaps someone could suggest a nice way of bridging what I produce in XCode to a universal web version. For example, if you come up with an algorithm in obj-c is it easiest to transition that to ruby and run it online, or is there another approach that works better?
Mathematica is pretty awesome for the first part of your question. I've used the interactive mode (Manipulate[]) for explaining things to my colleges (and myself). It makes really nice dynamic figures and is fairly expressive (although your code can end up looking like line noise). It is very powerful, but it does far less for you than you might think. It's pretty intuitive, which is a good thing for teaching.
You could use Scala if you want an "easy" way to make a domain specific language for teaching. Python seems to confuse people as a first programming language. Objective C seems like a completely random choice to me.
Mathematica then. It's worth the price. But anything that is interpreted and has an interactive shell is probably better than a compiled language. BBC BASIC?
Nothing beats Haskell for general-purpose mathematical programming. The wiki's quite extensive and the IRC channel (#haskell on Freenode) is great for asking questions. If you statically link your binaries on compilation, you should be able to run your programs on just about any system (with a few exceptions, e.g., libgmp).
Haskell code reads (roughly) like mathematical notation once you get the hang of it, so it can really help to tie things together for your students who are motivated to write their own programs. The purely functional style can be beneficial, as well, since it focuses less on I/O and the marshalling of data (perfectly useful in applications, perhaps less so in pure math), and more on the actual creation and refinement of functions and algorithms. You can even compose functions just as you would on paper.
If you want to get really serious, you could also look into Coq or Agda, but those might be a bit much for most classes.
For a Haskell program idea for an educator, check out this link.
A nice list of arguments can also be found at:
Eleven Reasons to use Haskell as a Mathematician and the book The Haskell Road to Logic, Maths and Programming

Chances of IDL in Image processing

I am a software engineer working in Medical Imaging.I have just started using the language IDL and i feel very comfortable with it.As a new member in this field with a language like IDL, i would like to know the chances of IDL in this field.Can any one help me?
Well, so here is my biased opinion -> I'm heading the opposite way to you. I have used IDL (and before PV-Wave) on and off for ca 10 years (mostly MRI) and I'm now trying to part from it. Here is why. If you are proficient you can very quickly test something in an interactive / lightly scripted fashion. This is the typical use case of scientists; most have little CS education and are happy to grab any tool that seems to helpful. In fact, IDL is fairly good at dealing with largish arrays/images etc as you are likely to encounter in imaging.
However, it is not very pretty and coding gets increasingly awkward as your project size increases. If you are a software engineer, I suspect you'll hit the limits soon and will be cursing it no end. If you try to develop GUI code for people around you, you might be in for a rough ride. This is one of the main reasons I am moving over to Python + EPD with scipy and the likes. Also, binding to existing sophisticated image processing tools as you might need (registration, segmentation, etc) are not ideal.
A further complaint I have are the ongoing licensing costs. Even in an academic environment they are becoming prohibitive and I'd rather spend it on a Coop-student who could code for me than on ITT. A nice feature though is the ability to compile almost all IDL code into a sav file that others can use with a free IDL virtual machine.
Essentially, what it will come down to is how much your collaborators need you to use IDL. If it's fully your choice, I would look elsewhere. If there is a significant (and decent) code base, I would stay. The medical imaging plus astro community is dependent enough to keep this going for a while. If you do decide to hang on, I can highly recommend Dave Fanning's writings (his web page + his book + the google-group). He is somewhat of an icon in the idl community and certainly taught me things that were very useful. (Check out the mighty histogram function, I'm not kidding!)
Hope this works out for you.

MUD Programming questions

I used to play a MUD based on the Smaug Codebase. It was highly customized, but was the same at the core. I have the source code for this MUD, and am interested in writing my own (Just for a fun project). I've got some questions though, mostly about design aspects. Maybe someone can give me a hand?
What language should I use? Interpreted or compiled? Does it make a difference? SMAUG is written in C. I am comfortable with a lot of languages, and have no problem learning more.
Is there a particular approach I should follow to not hinder performance? Object Oriented, functional, etc?
What medium should I use for storing data? Flat files (This is what SMAUG uses), or something like SQLite. What are the performance pros/cons of both?
Are there any guides that anyone knows of on how to get started on a project like this?
I want it to scale to allow 50 players online at a time with no decrease in performance. If I used Ruby 1.8 (very slow), would it make a difference compared to using Python 3.1 (Faster), or compiled C/C++?
If anyone can lend a hand and give some info or advice, I'd be eternally grateful.
I'll give this a shot:
In 2009, for a 50 player game, it doesn't matter. You may want to pick a language that you're familiar with profiling tools for, if you want to grow it further, but since RAM is so cheap nowadays, the constraints driving the early LPMUD (which I have experience with) and DikuMUD (which your Smaug is derived from) don't apply. (LPMUD could handle ~10-15 players on a machine with 8MB RAM)
The programming style doesn't necessarily lead to performance difficulties, large sites like Amazon's 'obidos' webserver are written in C, but just-as-large sites like the original Yahoo Stores were written in Lisp, StackOverflow is written in ASP.NET, etc. I'd /personally/ use C but many people would call me a sadist.
Flat Files are kind of pointless in today's day and age for lots of data storage, there are specific-case exceptions (Large mailservers sometimes use 'maildir' which is structured flat-files, for example). The size of your game likely means you won't be running into huge slowness driven by data retrieval delays, but the data integrity in-case-of-crash are probably going to make the most convincing argument.
Don't know of any guide, but what I'd do is try to get the game started as a dumb chat server to start, make sure users can log in and do something (take their input and dump it to all other users), then build that up to allowing specific logins, so you'll start facing the challenge of username/password handling, and user option setting / storage / retrieval ... then start adding the gamedriver elements (get tic tac toe games working in game), then go a little more complex (get a 5-room setup working with objects you can pick up / drop / bash each other with), then add some non-player characters, and THEN worry about slurping in the Diku-derived smaug castles / etc and working with them. :)
This is a bit off the cuff , I'm sure there are dissenting opinions. :) Good luck!
This is a text based game, right? In that case, with current hardware, it seems all you would have to worry about is not accidentally creating an O(n**2) algorithm. Even that probably wouldn't be too bad with 50 users.

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