6 ms·

qemu relies on being able to JIT compile, which isn't allowed in the sandbox.

• saagarjha 8y ago
  You can JIT compile in the sandbox with certain entitlements that Apple is happy to grant you, as long as you don’t try to put your binary on the App Store.
  • jsjohnst 8y ago
    Care to show how to do this or even an example of this being done? Extraordinary claims require proof.
    • saagarjha 8y ago
      Sure. If you have an Xcode and an iOS device on hand, make a new project and cast “\x00\x00\x80\x52\xc0\x03\x5f\xd6” (or your own assembly) to an int (*)(), and check to see if the return value is 42 in the debugger.
      • jsjohnst 8y ago
        That’s not getting the JIT entitlement as your prior comment claimed. ;)
        • saagarjha 8y ago
          It is, the entitlement is called “get-task-allow” and is usually used for saying that it’s ok to be attached to in the debugger, but serves a useful double life in making it possible to JIT. Xcode injects this entitlement for you when you create a debug build.
          • jsjohnst 8y ago
            But it only works when debugger is attached I thought (which isn’t a practical work around).
            • saagarjha 8y ago
              Nope, all you need to do is call ptrace: https://news.ycombinator.com/item?id=18431524 https://news.ycombinator.com/item?id=18431524
  • YetAnotherNick 8y ago
    How?
    • saagarjha 8y ago
      https://news.ycombinator.com/item?id=18431524 https://news.ycombinator.com/item?id=18431524