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Brief Tutorial on Reverse Engineering Mac OS X
rjw57 writes "There is an article on OSNews I wrote about how the guy behind Desktop Manager goes about reverse engineering APIs from Mac OS X with a brand new example not revealed anywhere else. From the article: 'I am often asked in email how I uncovered the API calls I use in Desktop Manager which are, unfortunately, undocumented. This article aims to give a little insight into the techniques I use to reverse engineer Mac OS X in order to provide extra functionality to users and extra information to third-party developers. In this article all the utilities I use are a standard part of Mac OS X's developer tools which are freely available.'"
All credit to the author; it looks like quite a feat of reverse engineering and some genius coding has probably gone into it. Apologies for the subsequent inflammatory opinion.
... try having a real discussion instead).
However, Apple have already come up with a perfect way of handling large groups of windows on one screen; it's called expose. I used to use virtual desktops on Linux, which was adequate, but when I got a Mac I settled in nicely with Expose; OS X has a near perfect user interface designed by actual HID experts. The only reason I can think of for using virtual desktops is if you're some kind of Linux zealot.
(Don't mod me down just because you're an anti-Mac zealot mod
Great example of apples practice of breaking API's leaving developers out of the loop
It's an undocumented, unsupported API; that's what the article is about. What broken APIs were you thinking of? Carbon took over most of the OS 9 ones (apart from some clearly documented exceptions).
If you had read the article you might actually have had something useful to say.
It's an undocumented API.
That's one of the many reasons why some APIs are left undocumented: because they are expected to be unstable.
Can't really blame Apple on this one. They didn't publish the API, and changed it in Tiger to a more flexible three-part solution. Eventually they may decide the design's a good one and publish the API.
Until then, use it at your own risk.
In this example, Apple broke undocumented APIs. Anyone writing or using an application that takes advantage of undocumented APIs should be prepared to discover that they've been changed, moved, or deleted entirely.
The APIs that DesktopManager uses were probably left undocumented precisely because Apple knew they were going to be subject to change.
Apple is good, and we are going to talk to talk about it.
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I myself have found that by really learning how to manage windows the "apple way" I don't really feel the need to use virtual desktops much (I used to use DesktopManager).
For me, this means using Hide (Command-H), Swich app (Alt-Tab), Focus on window (active) or next window (a custom key binding like Alt-Tab), and Expose.
But that doesn't mean there isn't a place for virtual desktops.
One thing that expose relies on is that the conceptual groupings of "All app windows" and "All of this apps windows" are all you need. The problem is if you have a large number of similar looking windows from different applications it can be difficult to manage even with Expose.
Virtual desktops can give you custom Expose groups - which can narrow the search for a particular window. This can be useful if you are working on several complex tasks that use multiple windows from multiple apps (each task can get its own desktop), and also have a bunch of side apps - like your calendar, email, instant messenger etc.
So Expose solves the window management problem to an extent, but it can be combined with virtual desktops when things become even more complex.
The story you linked to is about copyright infringement, not reverse engineering. It has nothing to do with TFA. Apple is not encrypting their undocumented code, so it has nothing to do with the DMCA. Reverse engineering is not necessarily banned by the DMCA; in fact, reverse engineering for interoperability is specifically exempt from it.
English is easier said than done.
So now we find out that Apple has used - and is using - undocumented API calls.
Sounds like something Microsoft would pull.
Oh, wait, this is Slashdot. I forgot.
Well, then Apple's just trying to protect its intellectual property. No harm.
So now we find out that Apple has used - and is using - undocumented API calls.
Um, no Apple has no applications that use the virtual desktop APIs to compete unfairly with third party apps. In fact Apple has no competing application in this area at all, and two of the three applications that DO exist are open source.
On Solaris there is a command truss that is the king of all truss-like commands. Unlike strace, ktrace, and BSD truss this tool can print a trace of all function calls made by an application as it runs (among many other useful things). Does anyone here know of an analogous tool for MacOS X? If not I wonder if an awk/perl script munging the output of nm to generate tracepoints for gdb where each trace point creates a new tracepoint at the instruction where the function call returns, prints out the funtion name and the contents of r2-r10 or so, then continues on or something like this would be something someone has already written.
"He who would learn astronomy, and other recondite arts, let him go elsewhere. " -- John Calvin, commenting on Genesis 1
No doubt an Appleista will be along in due course to make clear the path to enlightenment.
You called?
The answer to your difficulty is obvious: follow the money. What strategic advantage does Apple gain by not publicly documenting these APIs? A corner on the windows management market? I'm sure is worth a whole lot because you can see how much Apple charges for it at the Apple Store. Oh, wait, you can't, cause there is no such separate competing product that Apple profits by leveraging their OS.
vs. Windows, where, let's see, they made a substantial amount of their $50 Billion on by selling Office--which required that they kill their competition in Office applications.
"But what of IE?", I hear you plaintively cry. "Doesn't Microsoft give that away for free?" Certainly. But their clear strategy was to use the product to own the web, and IE was the platform to do it.
When Apple sells a virtual desktop management tool, besides the OS, and doesn't document the APIs, you'd have an argument. For example, I imagine QT has access to things that WMP doesn't, but proving that is an exercise for the reader. As it is, you're just trolling. Speaking of simplistic arguments.
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$tar -xvf
I know that it's fun to pick apart the framework code, make guesses as to what it's doing and how, and write code that exploits it in some way, but don't, don't, don't write a commercial product that depends on what you discover by this kind of spelunking, unless you are fully prepared to deal with the consequences of it breaking at any software update.
If your users call Apple because your program broke, Applecare will tell them to talk to you about it. If you ask Apple for help with an undocumented API, your request will be declined.
-jcr
The only title of honor that a tyrant can grant is "Enemy of the State."
I needed more workspace, so I went multihead. Some apps lend themselves well to virts - web browsing, email, a pile of xterms... but when you're running something like photoshop and you need more "room to maneuver". adding extra heads is the way to go.
:-(
:-|
I seem to be the only OS X user that neither uses no likes Expose much. Part of it's the fact that a few apps I use bind to F11-13, though my BIG gripe is that F14-F16 ARE NOT MAPPING OPTIONS. Why can't I put the shortcuts for Expose onto the three keys that I NEVER use for ANYTHING?
That aside, I've noticed that virts are something the "I used to use freenix but the desktop sucks so I switched" crowd complains about, as well as sloppy focus and the fact that portables have one button trackpads (something of an annoyance if you're using X11 applications). As a whole, the freenix imports seem to be so used to doing things Their Way that the mere notion of a UNIX not having $feature makes them positively apoplectic.
Why can't I put the shortcuts for Expose onto the three keys that I NEVER use for ANYTHING? :-(
What I want to know is why Apple hasn't put a general purpose input or hotkey manager in Preferences that would let you map any key combo to any hotkey-using application.
Plus, every second keyboard these days has half a dozen extra "Multimedia" or "Internet" buttons. Why can't I map those to actions?