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Reverse Engineering IRIX Multithreading For NetBSD

Posted by timothy on from the going-thattaway dept.

Anonymous Coward writes "Onlamp.com publishes the sixth paper of Emmanuel Dreyfus's series on NetBSD's IRIX binary compatibility implementation. This time, this is about reverse engineering IRIX multithreading and the odd virtual memory features involved with it. It's an adventure at kernel and userland boundaries, with a debugger as the sole weapon. A must read!"

5 of 32 comments (clear)

  1. Re:IRIX? by fyonn · · Score: 4, Insightful

    remember this isn't the commercial software world. no-one's been tasked with providing irix compatibility. someone's doing it because they want it and thats reason enough, isn't it?

    dave

  2. Re:IRIX? by Anonymous Coward · · Score: 2, Insightful

    I think most of Slashdot contributors miss the article point: it is not an advertising for running NetBSD instead of IRIX, it is a technical paper on the actual implementation and the reverse engineering techniques used to reveal IRIX undocumented secrets.

    IRIX binary compatibility is not sexy, indeed. But IMHO, the tricks exposed in the paper are quite interesting. There is not that much documentation on kernel programming and reverse engineering available around there.

  3. Some people are missing the point. by LizardKing · · Score: 3, Insightful

    Slashdot's usual bunch of Linux fanboys are missing the point of these articles. So SGI might move to Linux and might drop IRIX. They might port there apps to Linux (their developers are certainly experienced enough). However, SGI's future operating system strategy has little bearing on NetBSD.

    NetBSD has a strong following in the academic world (I'm talking about researchers and postgrads here, not undergrads running Linux file sharing apps in their dorm). The BSD license, along with clear and well documented source make Net an ideal choice for academic work. However, a lot of cutting edge work takes place outside academia, often in companies like Sun and SGI. Often this work is not publicly documented.

    Reverse engineering things like IRIX's kernel can give valuable insights into advancements made by SGI. These can then suggest new avenues for research that may have been overlooked otherwise.

    So those questioning the utility of IRIX binary compatability, are missing the primary motivation for such work. Of course someone may find the ability to run IRIX apps useful one day - after all, who would have thought that NetBSD's emulation of a niche operating system like Linux would have proved so useful ;-).

    Chris

    1. Re:Some people are missing the point. by Anonymous Coward · · Score: 2, Insightful

      Indeed reverse engineering IRIX gave NetBSD folks some ideas. The libc provided signal trampoline described in part 4 is a very good example.

      It removes one of the needs of an executable stack. Running with a non executable stack would be a great step forward: stack overflows exploits would not work anymore.

  4. support "legacy" users (Re:IRIX?) by Anonymous Coward · · Score: 1, Insightful

    SGI may be moving, but what about all its IRIX customers. Some may be happy running what they have now. This way even if the OS is no longer supported by SGI, the users can still run their apps on NetBSD.