Jabbering Giraffe

Recently, I’ve been using a Linux desktop for the first time in ages. It’s Ubuntu (Hardy Heron), and it looks nice. But after using a mac for three years, I’m really missing quite a few little things.

1. The ability to drag and drop anything anywhere.
2. Being able to type a wide range of Unicode characters easily.

On a mac, it’s really, really easy to type in a wide variety of useful characters. All you need is alt (⌥), sometimes known as “option”.

How did I find all this out? The lovely keyboard viewer that comes with OS X. You can get the flag in your menu bar by going to International in system preferences and checking “Show input menu in menu bar.”

Now, hold down alt and see what you can get (try alt and shift too).

But not everything is attached to a key. In case you need more characters, there’s always the character palette. Usually on the ⌥ ⌘ T key as well as in the Edit menu. Here, you can get access to the vast repertoire of characters in Unicode. Need an arrow?

There’s a lot you can do with the character palette, but the search box is probably the best way in. Just tap in a bit of the name of the character you’re looking for and see what turns up.

This easy access to a wide array of characters is something I’ve rather come to take for granted in OS X. So coming back to the Linux desktop, it was odd to find that I couldn’t as readily type them in. Of course, I haven’t invested the time in figuring out how to set up XKB correctly. Doubtless I could achieve many of the same things. But my past experiences of XKB and it’s documentation have shown me how complicated it can be, so I don’t rate my ability to pull it off.

The end result is that I’m spending most of my time on the (mac) laptop and ignoring the desktop. I do like my characters.

dom Uncategorized osx, unicode

I’ve just been debugging a problem with the pulse-agent on a mac. One of the big questions we had was: where the heck are the logs? The pulse-agent is managed by launchd. Apparently, this logs all stdout and stderr via ASL.

But what’s ASL? Apparently, it’s the Apple System Log. There’s a nice summary on Domain of the Bored. He also gives the key hint: you can use syslog(1) to read the binary ASL files.

I didn’t delve too deeply into the flags. It appeared that just running syslog spat out all the information I required. But, it comes out encoded like cat -v. But you can pipe it through unvis(1) to clean that up.

$ syslog | unvis | less

Normally, Console.app would take care of all this transparently. But when you’re ssh’d into a mac, that’s not an option. So it’s good to know about syslog(1).

Looking closer at the flags, you can say syslog -E safe in place of piping through unvis(1).

dom Uncategorized logging, osx

Just a quick note… I was looking at RT#48699 when I noticed that MacPorts didn’t have JavaScript.pm in it’s collection. I needed to install it by hand. Unfortunately, the latest version (1.12) doesn’t install cleanly.

So I’ve forked it and fixed it (along with a couple of other minor nits).

Claes said he’ll apply the patch at some point. So hopefully when 1.13 comes out, this won’t be necessary.

Of course, really I should get to grips with MacPorts and submit a Portfile…

dom Uncategorized javascript, osx, perl

This is somewhat niche, but I’m going to post it anyway in case it helps somebody else…

I recently saw a problem with Eclipse and m2eclipse. When I tried to import a Java 6 based project, I got an error in the maven console.

Failure executing javac, but could not parse the error:
javac: invalid target release: 1.6
Usage: javac  
where possible options include:
 -g                         Generate all debugging info
 -g:none                    Generate no debugging info
 -g:{lines,vars,source}     Generate only some debugging info
 -nowarn                    Generate no warnings
 -verbose                   Output messages about what the compiler is doing

This is happening because m2eclipse is trying to run the compiler from within the same JVM that Eclipse is running. And by the eclipse.org downloads only offer Carbon and Cocoa options. Both of these are 32 bit. Which means they’ll only ever run using Java 5, even if you’ve got Java 6 installed (unlike my iMac G5, grumble, grumble).

Thankfully, the 64 cocoa version is available, though it’s only the old “Eclipse SDK” download. But ekke wrote up [galileo] EPP for Cocoa 64-bit, which shows how to go about getting (effectively) the same setup as the eclipse.org downloads.

If you follow along that procedure, you get an eclipse that works well with m2eclipse and Java 6 project. As a bonus, it feels quicker to me.

Hopefully future versions of Eclipse will offer a 64-bit cocoa download.

dom Uncategorized eclipse, maven, osx

I’m just trying out Eclipse 3.5-RC4. One of the big new features for me is that it’s now based on Cocoa instead of Carbon. There are many benefits to this, including being able to run on 64-bit Java 6. Fundamentally, it just looks and feels a little bit more mac-like.

As an example, one nice little mac feature I use a bit is “lookup this word in the dictionary”. If you hit Ctrl-Cmd-D and hover over a word, you get an in-place definition. Eclipse now does this:

It doesn’t work everywhere (which you can probably guess from the context of that screenshot), but it is an indicator that Eclipse & mac are coming together. This is great news for Java developers on the mac.

Oh, it does feel a little bit faster too, which can’t hurt.

dom Uncategorized eclipse, osx

Like a lot of people, most of my Unix knowledge comes from an early reading of Advanced Programming in the UNIX Environment. This is an excellent tome on the interfaces provided by the kernel to programs on a Unix system.

Unfortunately, it’s over 15 years old now, and things have moved on. Naturally, I haven’t quite kept up. So I’ve just been pleasantly surprised to see that OS X has grown a sandbox system (via). There is scant documentation available:

• sandbox-exec(1)
• sandbox_init(3)
• sandbox(7)
• sandbox-compilerd(8)

Also, if you poke around, you’ll find /usr/include/sandbox.h and /usr/share/sandbox. The latter is interesting — it contains lisp-like definitions of access control lists for various processes.

What’s interesting to me is sandbox-exec though. This can be used with one of the builtin profiles to easily restrict access. For example:

$ sandbox-exec -n nowrite touch /tmp/foo
touch: /tmp/foo: Operation not permitted

After using strings(1) on apple’s libc (/usr/lib/libSystem.dylib), I managed to get these builtin profile names out:

nointernet

TCP/IP networking is prohibited

nonet

All sockets-based networking is prohibited.

pure-computation

All operating system services are prohibited.

nowrite

File system writes are prohibited.

write-tmp-only

File system writes are restricted to the temporary folder /var/tmp and the folder specified by the confstr(3) configuration variable _CS_DARWIN_USER_TEMP_DIR.

They’re only documented as internal constants for C programs, but it’s quite handy to have them available for sandbox-exec. It would be nice to know in more detail what they actually did, though.

Of course, this still isn’t really getting down to how the sandbox is implemented. Is it done inside the kernel or on the userland side? I don’t really know. And I don’t yet have enough dtrace-fu to figure it out.

See also:

• A brief introduction to Mac OS X SandBox Technology
• Apple Sandboxes Part 1
• Apple Sandboxes Part 2
• A Roundup Of Leopard Security Features

Anyway, this seems like a fun toy. And of course, it’s reminded me that I need to try out chromium on the mac… Drat, no PPC support.

dom Uncategorized osx, security, unix

This has been bugging me for a while, but I’ve just gotten around to doing anything about it. I hate the caps lock key. I never use it and I’m always triggering it by accident. Thankfully, it’s fairly simple to disable. First go into System Preferences and choose “Keyboard & Mouse”.

Now on the “Keyboard” tab, there’s a button in the bottom left that I’d managed to miss entirely, “modifier keys”:

This pops up a little dialog pane that lets you choose the behaviour of the caps lock key.

I chose control, as it’s not entirely useless. In fact, on my macbook, it’s a damned sight more useful than the hobbled control key which has been displaced by an “Fn” button.

dom Uncategorized osx

Thanks to a lengthy commute last week, I’ve been making a toy in Cocoa. It reads an URL, parses some XML and displays it in an NSOutlineView. Simple stuff, but it will hopefully make my life better at work, where I need to do this a fair bit.

By default, when I load the XML into the NSOutlineView, everything is closed up. So all you’re presented with is the root element. I’d like to expand that so it automatically includes all children of the root element. Nice and simple—there’s an expandItem: method.

Except that when I call it from the action that puts the XML into the NSOutlineView, it doesn’t work. Bugger.

After instrumenting my XML data source, I can see that nothing is really happening until after my action. My suspicion is that the NSOutlineView isn’t realising that it has any data until after the first call to display.

I tested this by hooking up the call to expandItem into a secondary action (on another button). And it works great.

So, I need a way to say “call this code back in the next idle period”. And this is where I start to get upset that Objective-C doesn’t have closures.

How to execute code soon isn’t easily determined from the apple docs. My guess is that you use an NSTimer with a very small NSTimeInterval . Let’s try that…

  NSTimer *idle = [NSTimer scheduledTimerWithTimeInterval:0.0
                                                   target:self
                                                 selector:@selector(expandRoot)
                                                 userInfo:nil
                                                  repeats:NO];
  [[NSRunLoop currentRunLoop] addTimer:idle forMode:NSDefaultRunLoopMode];

Well, it works. But! Further investigation finally reveals Deferring the Execution of Operations. This suggests that I should use an NSNotification instead, but posted with a NSPostWhenIdle flag. This means getting involved with the cocoa notifications system…

The code now ends up looking like this:

  - (void)awakeFromNib
  {
    // Listen out for notification's we've posted to ourselves.
    [[NSNotificationCenter defaultCenter] addObserver:self
                                             selector:@selector(expandRoot:)
                                                 name:@"expandRoot"
                                               object:nil];
  }

  -(IBAction)fetch: (id)sender
  {
    // …
    NSNotification* todo = [NSNotification notificationWithName:@"expandRoot"
                                                         object:self];
    [[NSNotificationQueue defaultQueue] enqueueNotification:todo
                                               postingStyle:NSPostWhenIdle];
  }

  - (void)expandRoot:(NSNotification *)notification
  {
    [outlineView expandItem:[[outlineViewDataSource doc] rootElement]];
  }

Which is quite a bit more code. But it feels more robust doing it this way.

The big take away from all this is how difficult it is to use a non-Open-Source framework. If I had the source to Cocoa, I’d be able to look inside and see what I needed to do simply and quickly. Instead, it took me three train journeys. But there’s still enough to like in Cocoa that I intend to carry on.

dom Uncategorized cocoa, mac, osx

I’ve tried iTerm a few times before, and not really got on with it. I wandered past today however, and noticed that the new version has a full screen option. Yummy.

So I’m giving it a trial run. It’s taken a little bit of setup to work correctly with the damned Linux boxes at work. Mostly this is ensuring that the backspace key sends a backspace instead of a delete¹. I also had to turn on option translating to ESC+key, as my emacs-ingrained fingers know that Option-F is forward-word.

Oh, and turning off the tabs as much as possible. I like tabs in my browser, but in a terminal, I’d rather use screen.

But apart from those (minor) quibbles, it seems to be a good little program. I’ll keep going with it for now. And the full screen mode works a treat. It’s just like PuTTY.

¹ I hate doing this, but I can’t be bothered to mess around with the Linux boxes.

dom Uncategorized osx

I got really caught out today. I needed to get some code samples from TextMate into Keynote. Cut’n’paste didn’t copy across the colours correctly. Kind of to be expected, since TextMate is a plain text editor, not a rich text editor.

After having a quick hunt around, I found the “Create HTML from Selection” command, which looked like just the ticket. Except that it produced HTML with lots of classes and no CSS (i.e. losing all the style). I played with it a bit, and the “Create CSS from Current Theme” command, all to no avail.

Eventually, I hopped onto irc and wandered into ##textmate on freenode.net. After a brief chat with several people whilst I explained my problem (badly), Allan Odgaard (textmate’s author) noticed that I had the selection enabled. Getting rid of the selection makes a new command appear, “Create HTML from Document”. And that loads into Safari just fine, from where it can be correctly cut’n’pasted into Keynote. Marvellous!

But more than anything, I can’t help but be impressed by the support that Allan offers. This was the middle of Sunday afternoon, and he personally answered my query to completion within 10 minutes. All I can say is that TextMate is well worth the money.

dom Uncategorized osx, textmate