707.srt

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[ Silence ]

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>> Jerry Cottingham:
Good Morning.

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I'm Jerry Cottingham, I'm an
engineer on the Core OS IO team

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and today we're going to talk

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about what's new in
Kext Development.

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So in my part of the
session, I'm going to talk

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about Kext Development
overview, give you a little bit

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of overview of the
Kext development.

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The Developer ID program,
why that's important for you

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and your attention please, I'm
going to call out some things

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that are in OS X 10.9 that
you need to be aware about.

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We're assuming that
the target audience

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for this is somebody that's
already developing a kext,

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you think you're about
to develop a kext.

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And if you're here, you know the
top three reasons why you need

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to avoid writing a kext
if at all possible.

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So if you're thinking about
it then here's a couple things

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So if you're thinking about
it then here's a couple things

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that you need to think

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about before you get
into writing a kext.

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Kexts require wired
memory, so all the memory

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that your kext consumes
is not available

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for the rest of the system.

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Mistakes are often fatal,

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so if you run it writing an
application, you make a mistake,

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you crash the application.

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You're writing a kext, you
make a mistake and you crash,

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you're crashing the whole
system so you affect everybody.

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Debugging is harder.

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So today, if you're developing
an application with Xcode,

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debugging is very
simple, very, very simple.

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If you're debugging a kext,
you need two machines,

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you need to setup the machine,

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you need to configure
it correctly.

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The problems that you're dealing
with are often much harder

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to figure out, so
debugging is much harder.

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So, if you're still not deterred
and you still really think

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that you need to develop a kext,

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then if you must there's
two things that you need

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to read before you even start
writing your first line of code.

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to read before you even start
writing your first line of code.

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The Kernel Extension
Programing Topics

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and the Kernel Programing
Guide, so make sure you read

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through those, and if you
still need to develop a kext,

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make sure you talk to us to
see if there's any other way.

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And, if you're going
to write a kext,

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you're mantra should always be,

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"With great power comes
great responsibility."

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Now let's quickly go
over a little overview

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of what kext development
is all about.

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So a kext is just a bundle
that extends the kernel.

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Kext stands for:
Kernel Extension,

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and it's only available
for OS X.

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So if you're trying
to write a kext

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for iOS, we don't allow that.

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And a kext is structured
just like any other CFBundle.

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Do you see the binary
down in the OS folder?

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So here the Apple sample PCI
kext, you're going to see this

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through all three of our talks
today about kext development.

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You'll see that the executable
is down in the OS folder.

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The Info.plist describes all
the properties of your kext

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and I'm going to call out
two here that we're going

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to discuss later today.

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The CFBundleIdentifier, so
that identifies your kext

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in the whole kext name space,
so that's a unique identifier

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across the whole system.

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CFBundleVersion, so that allows
the kext management system

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to figure out which
of your kexts,

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if it has the same
bundle ID to load.

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Now this becomes very
important and today when we talk

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about some of the other
things that we're changing,

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that you are bumping that
version number as you go along.

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Okay, so you're part of the
kernel and part of that means

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Okay, so you're part of the
kernel and part of that means

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that you have to buy
into extra protection.

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So, we require specific
File and Folder permissions.

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Kexts must be owned by root
and the group must be wheel.

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Must only be writable by
root, and permissions are deep

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so this little folder here on
the right shows you if you did

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like an 'ls -alR' all
permissions all the way

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through would look like that.

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If you get any of
those incorrect,

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your kext will not load.

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And you can use kextutil
-tn which is test no load

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to verify your kext as
you're developing it.

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Okay new in OS X 10.9, we
are now code signing kexts

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and checking the
signature of your kext.

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In OS 10.9 all kext
signatures are verified.

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In OS 10.9 all kext
signatures are verified.

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Unsigned or invalid
signatures are not fatal

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with just one exception
and I'll talk

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about that exception
in just a little bit.

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So if you sign a kext in
10.9 and try to run it

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on earlier versions, newer
than 10.8, it will not load,

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there was some code signing
machinery changes in there

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that will not allow those to
load, so just keep that in mind.

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Valid code signatures will
eventually be mandatory

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on all kexts.

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So now in 10.9, there's
only one place its mandatory

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and I'll talk about that, but
be prepared, be proactive.

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Let's get your kexts signed and
you'll be ready for the future.

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And again, kextutil -tn is good

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for testing your
code signatures.

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Now I have to mention in the
seed that you have today,

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I didn't quite get around
to getting that working,

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I didn't quite get around
to getting that working,

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so it's fixed in the next
seed they will actually test,

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so you can just try a kext
load to verify your signature.

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Okay so now I want to talk
a little about kext loading.

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So there's three types of loads
here I want to talk about.

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Autoload. So autoload is
basically your IOKit KEXT

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when it matches hardware that's
attached to your machine,

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the kext machinery goes
through, matches the best driver

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for that, and loads it for you.

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Now, where we find
those kexts now is

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in /System/Library/Extensions.

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So on-demand loading
of kexts, so you can do

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that by an explicit path,
so here we're using kextload

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with our Apple sample PCI kext.

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So I just give it
a specific path.

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You can also use your
CFBundleIdentifier.

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So here is kextload -b with a
big, long bundle ID that we have

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for our sample kext, and again,
if you supply nothing else

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for our sample kext, and again,
if you supply nothing else

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to kextload, we'll go
search for that bundle ID

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in System/Library/Extensions.

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And the other place that
your kext gets loaded is

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from the kernel cache.

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So the kernel cache is built to
speed up the boot of the system

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and in there is anything
that is required for booting,

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for rooting, anything that needs

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to be loaded early can be
put in the kernel cache.

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And again, when we
build that, by default,

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we'll look for those kexts out
of System/Library/Extensions.

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So you see a pattern there

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that /System/Library/Extensions
is very important

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for us finding kexts
automatically.

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Okay now in 10.9, autoload,
on-demand load by bundle ID

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and kernel cache builds
will look not only

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in /System/Library/Extensions,
but also /Library/Extensions.

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So, and again, if you touch,

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the /System/Library/Extensions
we will automatically rebuild

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the /System/Library/Extensions
we will automatically rebuild

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the kernel cache.

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/Library/Extensions is the
same thing except, again,

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the seed that you have,

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that will not work
until the next seed.

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We have a fix that
I just put in.

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Okay, and you must sign
your kext if you're going

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to deploy them in
/Library/Extensions.

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So this is the exception I
was talking about earlier.

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So, if it's not signed, we
will not load it from there.

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Okay. So we've done
some research to find

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out where your kext is
already installed recently.

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Of course,
/System/Library/Extensions

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and those are needed for
autoload or autosearch.

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/Library/Application
Support, that's a fine place,

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and that's where you guys are.

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/System/Library/Extensions/File
Systems,

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that's where mainly our
file system kexts are.

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/Library/File Systems are
your File System kexts.

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Library startup items, in
the application folder,

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Library startup items, in
the application folder,

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inside your app bundles,
that's a perfectly good place

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for your kexts and
/Library/Extensions.

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Again, it did not support
autosearch or autoload.

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In OS 10.9, same setup, these
are all perfectly fine places

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and now we have the
autoload and autosearch

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in /Library/Extensions and,
again, the caveat there is

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that they must be signed.

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Okay where we want
your kexts installed.

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So the autoload kext that
required rooting, booting,

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early, you know, early
load from the kernel cache

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and autosearching of
kexts, again, we want those

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in /Library/Extensions
and they must be signed.

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/System/Library/Extensions
for compatibility.

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So if you have shipping kexts
out there, which you already do,

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it's fine to leave those in
/System/Library/Extensions.

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As you revise and start
signing your kexts,

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move them to
/Library/Extensions,

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move them to
/Library/Extensions,

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and anything on 10.8 and
earlier, the unsigned kexts,

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leave them in
/System/Library/Extensions,

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that's fine, all other
kexts though, any other kext

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that doesn't need
to be autoloaded

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or automatically
found by the system.

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Signed kexts can go into
/Library/Extensions,

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so just because we autosearch
and autoload from there,

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if you sign your kext, it's
still fine to put it in there.

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Even if you don't
need to be autoloaded.

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Do not install anywhere
in /System.

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So in the future, we are
going to tighten down access

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to the system hierarchy,
the whole hierarchy

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down from /System and
everything in there.

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So, be proactive and stay out of
there because changes are coming

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that will require
that you not be there.

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So all the other common
locations that I talked about,

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applications in your application
bundle, all those are fine.

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applications in your application
bundle, all those are fine.

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So, you may need to have
two kexts for compatibility

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and in a little bit we'll
show you actually how

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to build those kexts, sign them,

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and deploy them across
multiple OS's.

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Okay. So, we're talking
about signing your kexts,

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so how do you go about that?

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The Developer ID
Program is your mechanism

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to get your kext signed.

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So what is this?

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Its part of the Mac
Development Program,

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which you're probably
already a member of.

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It allows distribution

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of applications outside
of the Mac App Store.

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So a kext is not
going to be delivered

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through the Mac App Store,

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so this is actually a
great place for you guys.

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And then you get a special
Developer ID Certificate

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for signing your applications
and now in OS 10.9 you're going

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to get a new certificate for
signing applications and kexts.

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So how do you go about getting
this Developer ID Certificate?

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So how do you go about getting
this Developer ID Certificate?

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Very simple.

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So you go up to
developer.apple.com,

00:12:10.386 --> 00:12:13.496 A:middle
Resources/Developer ID,
you click on the link

00:12:13.496 --> 00:12:15.996 A:middle
to request a Developer
ID Certificate,

00:12:18.086 --> 00:12:22.096 A:middle
you fill out the form, and then
once the form is approved you'll

00:12:22.096 --> 00:12:24.486 A:middle
go back to the Member Center

00:12:24.896 --> 00:12:28.546 A:middle
and in
Certificate/Identifier/Profiles

00:12:29.246 --> 00:12:31.466 A:middle
you will see this.

00:12:32.386 --> 00:12:33.896 A:middle
This should be active
right now, by the way,

00:12:33.896 --> 00:12:35.016 A:middle
so you should be able to go up

00:12:35.046 --> 00:12:37.176 A:middle
and get your certificate
right now,

00:12:37.356 --> 00:12:39.376 A:middle
so click on the Developer
ID Application

00:12:39.376 --> 00:12:43.126 A:middle
and kernel extensions,
and you're ready to go.

00:12:43.836 --> 00:12:45.866 A:middle
So for more information
you can go back

00:12:45.866 --> 00:12:49.376 A:middle
up to developer.apple.com
and then, also,

00:12:49.376 --> 00:12:54.906 A:middle
Session 702 from last
year's WWDC, Perry talked

00:12:54.906 --> 00:12:57.416 A:middle
about Gatekeeper and
Developer ID, so he talked

00:12:57.416 --> 00:12:59.386 A:middle
about the Developer
ID Program last year

00:12:59.926 --> 00:13:01.676 A:middle
in context for applications.

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00:12:59.926 --> 00:13:01.676 A:middle
in context for applications.

00:13:02.376 --> 00:13:06.106 A:middle
All that stuff he talked about
in that session, he gives a lot

00:13:06.106 --> 00:13:07.486 A:middle
of information about
code signing,

00:13:07.486 --> 00:13:09.146 A:middle
is applicable to you guys too.

00:13:09.416 --> 00:13:12.316 A:middle
So go back and look at
that, there's a great deal

00:13:12.316 --> 00:13:14.046 A:middle
of information there for you.

00:13:15.266 --> 00:13:22.036 A:middle
Okay. So in the seed that
you have now, in 10.9,

00:13:22.636 --> 00:13:24.546 A:middle
I want to call out some
things that are going

00:13:24.546 --> 00:13:27.116 A:middle
to affect you and our customers.

00:13:27.736 --> 00:13:31.146 A:middle
The first thing, as I said
before, /Library/Extensions,

00:13:31.246 --> 00:13:33.676 A:middle
kexts in /Library/Extensions
will not load

00:13:33.986 --> 00:13:37.226 A:middle
if they're unsigned or if
the signature's invalid.

00:13:39.136 --> 00:13:43.716 A:middle
So what this means is that
the user will see this no load

00:13:44.176 --> 00:13:45.526 A:middle
alert dialogue.

00:13:46.676 --> 00:13:51.276 A:middle
Basically, it says the kext is
not going to load and the part

00:13:51.276 --> 00:13:53.416 A:middle
that affects you is that
very last line in there

00:13:53.416 --> 00:13:57.266 A:middle
that says contact the Developer
to get updated software.

00:13:59.296 --> 00:14:02.616 A:middle
There's a second alert
that will come out.

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00:13:59.296 --> 00:14:02.616 A:middle
There's a second alert
that will come out.

00:14:03.166 --> 00:14:07.666 A:middle
Anything that is a kext outside
of /Library/Extensions will load

00:14:08.046 --> 00:14:13.046 A:middle
if it's unsigned or if it has
a signature validation problem,

00:14:14.856 --> 00:14:17.016 A:middle
but the user will
see another alert.

00:14:17.186 --> 00:14:20.506 A:middle
In that particular case, it
will say that yes we're going

00:14:20.506 --> 00:14:23.856 A:middle
to load it, but please
contact the vendor

00:14:23.856 --> 00:14:30.716 A:middle
to get an updated
version on this.

00:14:30.926 --> 00:14:34.986 A:middle
Also, what you guys will see as
you develop your kext and some

00:14:34.986 --> 00:14:36.686 A:middle
of your customers might
contact you and say, "Hey,

00:14:36.686 --> 00:14:41.476 A:middle
I saw this thing in the System
Log," so there's some warnings

00:14:41.476 --> 00:14:43.686 A:middle
and error messages, so
the warnings would be

00:14:44.046 --> 00:14:47.036 A:middle
if it's actually going to load
the kext, but it has some kind

00:14:47.036 --> 00:14:51.476 A:middle
of problem in verification,
and the error messages are

00:14:51.476 --> 00:14:52.456 A:middle
when you get that alert

00:14:52.456 --> 00:14:56.036 A:middle
that says I'm not going
to load it at all.

00:14:56.096 --> 00:15:00.146 A:middle
So the most common code
signature error codes

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00:14:56.096 --> 00:15:00.146 A:middle
So the most common code
signature error codes

00:15:00.146 --> 00:15:04.086 A:middle
that you're going to
see is the -67030,

00:15:04.236 --> 00:15:07.416 A:middle
which means that something in
the bundle has been modified.

00:15:07.946 --> 00:15:12.126 A:middle
Something that, the kext
signature is no longer valid,

00:15:12.126 --> 00:15:16.146 A:middle
so if somebody went in and
messed with your Info.plist,

00:15:16.606 --> 00:15:17.876 A:middle
then you're going
to get this error.

00:15:19.146 --> 00:15:25.156 A:middle
The other one is -67062, which
is the kext is not code signed,

00:15:25.156 --> 00:15:27.926 A:middle
which means there's no
signature at all on this kext.

00:15:30.346 --> 00:15:34.216 A:middle
So there's all kinds of error
codes in the security framework

00:15:34.216 --> 00:15:37.796 A:middle
and you can go to the
cs.h and see all those.

00:15:38.796 --> 00:15:43.956 A:middle
So here's an example of when I
took the Apple sample PCI.kext,

00:15:44.686 --> 00:15:50.676 A:middle
built it, had it signed, then
I went into the Info.plist file

00:15:50.676 --> 00:15:52.926 A:middle
and changed just
a line in there,

00:15:53.786 --> 00:15:55.246 A:middle
and then I tried
to load the kext.

00:15:55.246 --> 00:15:58.356 A:middle
And so this is exactly
what you're going to see

00:15:58.356 --> 00:15:59.396 A:middle
in that particular case.

00:15:59.516 --> 00:16:03.106 A:middle
So this is an example of
a modified Info.plist,

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00:15:59.516 --> 00:16:03.106 A:middle
So this is an example of
a modified Info.plist,

00:16:03.396 --> 00:16:04.776 A:middle
invalidates the signature,

00:16:04.776 --> 00:16:08.306 A:middle
and this is the message
that you'll get.

00:16:08.496 --> 00:16:14.896 A:middle
Okay, in summary, sign your
kext with your Developer ID,

00:16:14.896 --> 00:16:16.106 A:middle
it's very simple and easy,

00:16:17.406 --> 00:16:19.646 A:middle
get out of
/System/Library/Extensions

00:16:19.866 --> 00:16:25.536 A:middle
as quickly as possible, in fact,
all of /System, and if you think

00:16:25.536 --> 00:16:29.116 A:middle
that you need to be in /System
for some reason anywhere down in

00:16:29.116 --> 00:16:31.996 A:middle
that hierarchy anywhere, please
talk to us and let us know

00:16:31.996 --> 00:16:34.306 A:middle
so we can provide
alternatives to that.

00:16:34.816 --> 00:16:41.006 A:middle
And get your kexts into
/Library/Extensions.

00:16:41.006 --> 00:16:42.756 A:middle
Okay, now Dean Reece
is going to come up

00:16:42.986 --> 00:16:45.396 A:middle
and actually show you how to
build your kext, get it signed,

00:16:45.396 --> 00:16:47.936 A:middle
and deployed across
many versions of the OS.

00:16:47.936 --> 00:16:49.226 A:middle
[ Applause ]

00:16:49.226 --> 00:16:49.426 A:middle
>> Dean Reece:Hi.

00:16:54.656 --> 00:16:56.276 A:middle
Thanks for joining us today.

00:16:56.476 --> 00:16:59.146 A:middle
My name is Dean Reece and
I manage the IOKit Team

00:16:59.146 --> 00:17:01.486 A:middle
in Core OS, and I'm
just going to run

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00:16:59.146 --> 00:17:01.486 A:middle
in Core OS, and I'm
just going to run

00:17:01.486 --> 00:17:04.366 A:middle
through a couple examples
real quick.Let's get started

00:17:05.215 --> 00:17:08.506 A:middle
with the most basic
project here just to kind

00:17:08.506 --> 00:17:10.415 A:middle
of set a base to start from.

00:17:10.836 --> 00:17:13.526 A:middle
We're going to build a kext that
follows the new signing rules

00:17:13.526 --> 00:17:15.455 A:middle
and installation
paths and only loads

00:17:15.455 --> 00:17:23.906 A:middle
on OS X 10.9.So you're going to
need to use at least OS X 10.8.3

00:17:23.906 --> 00:17:26.606 A:middle
as your minimum build
for the build machine

00:17:26.945 --> 00:17:29.036 A:middle
and this is necessary to
get correct code signing.

00:17:29.036 --> 00:17:32.616 A:middle
It was a change to the security
framework that's available

00:17:32.676 --> 00:17:34.976 A:middle
in that build and
later OS releases.

00:17:36.106 --> 00:17:39.306 A:middle
You're also going to need
to use Xcode 4.6 or later,

00:17:39.436 --> 00:17:41.836 A:middle
and for these examples
I'm showing you Xcode 5

00:17:41.916 --> 00:17:42.636 A:middle
which is preferred.

00:17:43.256 --> 00:17:46.186 A:middle
And as Jerry described,
you're going to need

00:17:46.186 --> 00:17:48.626 A:middle
that Developer ID
Certificate that allows you

00:17:48.626 --> 00:17:51.876 A:middle
to sign kernel extensions,
and you're going to install

00:17:51.876 --> 00:17:56.026 A:middle
that on your keychain so
Xcode can get to it.Okay,

00:17:56.026 --> 00:17:59.266 A:middle
so you create a new Xcode
project and there's two flavors

00:17:59.266 --> 00:18:02.766 A:middle
of kernel extensions: The
"Generic Kernel Extension",

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00:17:59.266 --> 00:18:02.766 A:middle
of kernel extensions: The
"Generic Kernel Extension",

00:18:02.766 --> 00:18:05.366 A:middle
which is typically used for File
Systems and network plug-ins.

00:18:05.786 --> 00:18:07.816 A:middle
An "IOKit Driver",
which is typically used

00:18:07.816 --> 00:18:12.626 A:middle
for autoload hardware
drivers.And you'll go

00:18:12.626 --> 00:18:15.156 A:middle
through the normal creation
process so we'll give it a name,

00:18:15.156 --> 00:18:19.966 A:middle
a unique bundle identifier,
and you have a project ready

00:18:19.966 --> 00:18:22.066 A:middle
to start putting code into.So,

00:18:22.306 --> 00:18:24.716 A:middle
we're going to set a
few properties and most

00:18:24.716 --> 00:18:26.566 A:middle
of these are going to default
this way, but a couple won't

00:18:26.566 --> 00:18:30.306 A:middle
so we'll walk through those
very quickly.Make sure

00:18:30.306 --> 00:18:32.506 A:middle
"Architectures" is set to
"Standard Architectures".

00:18:32.506 --> 00:18:39.026 A:middle
You only need to building for
64-bit Intel on OS X 10.9.

00:18:39.396 --> 00:18:40.936 A:middle
And also make sure
the "Base SDK" is set

00:18:40.936 --> 00:18:48.296 A:middle
to "Latest OS X (OS X
10.9)".Under Code Signing,

00:18:48.296 --> 00:18:51.086 A:middle
this is new for kernel
extensions, so you're going

00:18:51.086 --> 00:18:52.936 A:middle
to want to change the
"Code Signing Identity"

00:18:53.006 --> 00:18:54.426 A:middle
to your Developer ID Certificate

00:18:54.596 --> 00:18:55.916 A:middle
that you've installed
on your keychain.

00:18:55.916 --> 00:18:58.456 A:middle
You can set it to this setting

00:18:58.456 --> 00:19:00.196 A:middle
which would match
any Developer ID.

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00:18:58.456 --> 00:19:00.196 A:middle
which would match
any Developer ID.

00:19:00.196 --> 00:19:03.056 A:middle
If you have multiple
Developer ID Certificates,

00:19:03.126 --> 00:19:05.916 A:middle
then you might have to pick the
specific one that is authorized

00:19:05.916 --> 00:19:11.456 A:middle
for signing kernel extensions.In
the deployment section,

00:19:11.826 --> 00:19:13.336 A:middle
another change here,
you're going

00:19:13.336 --> 00:19:14.946 A:middle
to have change the
installation directory.

00:19:14.946 --> 00:19:17.416 A:middle
It will default to
/System/Library/Extensions,

00:19:17.416 --> 00:19:18.796 A:middle
and of course as we said,

00:19:18.796 --> 00:19:21.576 A:middle
that is now /Library/Extensions
for OS X 10.9.

00:19:22.126 --> 00:19:29.336 A:middle
And the deployment target should
match.We're not going to go

00:19:29.936 --> 00:19:32.226 A:middle
into the actual coding
of the kernel extension,

00:19:32.226 --> 00:19:33.816 A:middle
that's outside the
scope of this talk,

00:19:33.816 --> 00:19:35.306 A:middle
but there's a few quick
reminders that I wanted

00:19:35.306 --> 00:19:38.106 A:middle
to give you.When you're
developing a kernel extension,

00:19:38.296 --> 00:19:40.446 A:middle
you may only use
headers that you find

00:19:40.446 --> 00:19:41.546 A:middle
in the Kernel.framework.

00:19:41.956 --> 00:19:44.866 A:middle
The Kernel.framework is intended
for use by kernel extensions

00:19:45.456 --> 00:19:48.216 A:middle
and conversely, it cannot
be used by applications.

00:19:48.576 --> 00:19:51.036 A:middle
So all the other frameworks
are for applications,

00:19:51.746 --> 00:19:56.996 A:middle
Kernel.framework is for kexts.If
you're writing an autoload kext

00:19:56.996 --> 00:20:00.406 A:middle
or IOKit kext and you
happen to subclass OSObject

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00:19:56.996 --> 00:20:00.406 A:middle
or IOKit kext and you
happen to subclass OSObject

00:20:00.406 --> 00:20:02.336 A:middle
or any class that's
derived from it,

00:20:02.336 --> 00:20:05.996 A:middle
which all the IOKit classes are,
then you must use the OSDeclare

00:20:05.996 --> 00:20:08.366 A:middle
and OSDefine macros
that you'll find

00:20:08.366 --> 00:20:10.446 A:middle
in the OSMetaClass.h header.

00:20:10.916 --> 00:20:13.176 A:middle
This is important for
our binary compatibility.

00:20:14.186 --> 00:20:18.126 A:middle
This includes additional symbols
that our run-time system picks

00:20:18.126 --> 00:20:20.366 A:middle
up and uses so that we
can patch up your kext

00:20:20.366 --> 00:20:21.666 A:middle
and make it binary compatible

00:20:22.056 --> 00:20:23.496 A:middle
with whatever OS
you're loading it on.

00:20:23.916 --> 00:20:28.686 A:middle
So, for example, if you build a
kernel extension using the OS X

00:20:28.686 --> 00:20:32.596 A:middle
10.8 SDK and you fail
to use these macros,

00:20:33.166 --> 00:20:36.456 A:middle
that kext will only ever load
on OS X 10.8; it won't load

00:20:36.456 --> 00:20:43.456 A:middle
on OS X 10.9, you'll get symbol
errors.And the last thing,

00:20:43.676 --> 00:20:47.456 A:middle
is you need to not strip those
binary compatibility symbols

00:20:47.456 --> 00:20:48.956 A:middle
out of the binary.

00:20:48.956 --> 00:20:50.796 A:middle
You can use "strip -S -x".

00:20:50.976 --> 00:20:54.656 A:middle
That's safe for stripping
a kernel extension binary,

00:20:55.116 --> 00:20:57.696 A:middle
but anything more restrictive
might rip out those symbols

00:20:57.696 --> 00:21:05.176 A:middle
that we need.The project we
just described builds one kext.

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00:20:57.696 --> 00:21:05.176 A:middle
that we need.The project we
just described builds one kext.

00:21:05.906 --> 00:21:10.086 A:middle
It will load on OS X 10.9
with no errors or warnings

00:21:11.016 --> 00:21:12.966 A:middle
and you're going to
debug it using lldb.

00:21:12.966 --> 00:21:16.666 A:middle
In a few minutes Brian's going
to join us and describe how

00:21:16.666 --> 00:21:20.586 A:middle
to do that, but you'll need
to be running OS X 10.9

00:21:20.586 --> 00:21:24.346 A:middle
on both the target system
and your host system

00:21:24.346 --> 00:21:29.716 A:middle
for that lldb connection.And
of course after you package it,

00:21:29.986 --> 00:21:33.196 A:middle
part of your Q.A. process
should be to verify

00:21:33.196 --> 00:21:35.426 A:middle
that it is installing
in Library/Extensions.

00:21:35.546 --> 00:21:37.756 A:middle
I think that might
have come up once

00:21:37.846 --> 00:21:43.526 A:middle
or twice.Now let's expand
this project a little bit

00:21:43.576 --> 00:21:46.136 A:middle
and we're going to add
support for OS X 10.8.

00:21:47.186 --> 00:21:49.186 A:middle
To do that, we're going
to create a new target,

00:21:50.066 --> 00:21:52.686 A:middle
and we'll have visit those
same settings that we talked

00:21:52.686 --> 00:21:56.416 A:middle
about before.But
before we do that,

00:21:56.536 --> 00:21:59.296 A:middle
we're going to check
our version numbers.

00:21:59.796 --> 00:22:01.826 A:middle
Now, this is very
important; this calls back

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00:21:59.796 --> 00:22:01.826 A:middle
Now, this is very
important; this calls back

00:22:01.826 --> 00:22:03.186 A:middle
to what Jerry told you earlier.

00:22:03.186 --> 00:22:06.776 A:middle
If you have multiple copies
of your kexts installed

00:22:06.776 --> 00:22:09.326 A:middle
on the system, and the system
encounters both of them,

00:22:09.326 --> 00:22:13.266 A:middle
it's going to pick the one with
the highest version number.

00:22:13.266 --> 00:22:15.396 A:middle
Because of the way that
this project is going

00:22:15.396 --> 00:22:18.356 A:middle
to install its kexts,
we're going to say

00:22:18.356 --> 00:22:21.866 A:middle
that the target intended for
Mavericks, for OS X 10.9,

00:22:22.256 --> 00:22:23.846 A:middle
will have a higher
version number.

00:22:24.396 --> 00:22:27.216 A:middle
And that the one intended

00:22:27.216 --> 00:22:30.006 A:middle
for OS X 10.8 will have
the lower version number.

00:22:31.046 --> 00:22:36.326 A:middle
The reason this works is
because the newer kext is going

00:22:36.326 --> 00:22:38.226 A:middle
to be installed in
/Library/Extensions,

00:22:38.336 --> 00:22:41.146 A:middle
and older OS's don't look there
so they won't see it by default,

00:22:41.726 --> 00:22:43.056 A:middle
they won't know about
the newer version

00:22:43.056 --> 00:22:43.796 A:middle
and they'll just ignore it.

00:22:45.176 --> 00:22:49.566 A:middle
Whereas Mavericks will see
the newer one and load it

00:22:51.496 --> 00:22:53.576 A:middle
by preference.Okay, so let's go

00:22:53.576 --> 00:22:55.366 A:middle
and visit those same
build settings we talked

00:22:55.366 --> 00:22:56.356 A:middle
about last time through.

00:22:57.056 --> 00:23:01.136 A:middle
Your new OS X 10.8
target is going

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00:22:57.056 --> 00:23:01.136 A:middle
Your new OS X 10.8
target is going

00:23:01.136 --> 00:23:04.126 A:middle
to have the same
architecture setting,

00:23:04.126 --> 00:23:05.746 A:middle
again you only need
64-bit Intel there,

00:23:06.066 --> 00:23:09.886 A:middle
but your "Base SDK" will be
"OS X 10.8" in this case.And

00:23:10.776 --> 00:23:12.486 A:middle
of course "Code Signing
Identity" will default

00:23:12.486 --> 00:23:14.986 A:middle
to "Don't Code Sign", but you
should verify that is the case,

00:23:15.036 --> 00:23:19.426 A:middle
because you don't
want it signed.And the

00:23:19.666 --> 00:23:22.326 A:middle
"Installation Directory"
in this case will need

00:23:22.326 --> 00:23:27.376 A:middle
to be
/System/Library/Extensions,

00:23:27.376 --> 00:23:29.516 A:middle
and the "OS X Deployment
Target" needs

00:23:31.876 --> 00:23:33.566 A:middle
to match the SDK.This
project now builds two

00:23:33.566 --> 00:23:34.476 A:middle
kernel extensions.

00:23:35.186 --> 00:23:36.876 A:middle
The signed one is
exactly the same

00:23:36.876 --> 00:23:38.376 A:middle
as the one we built
in the first example.

00:23:38.956 --> 00:23:41.896 A:middle
And the unsigned kext
that is being built

00:23:41.896 --> 00:23:45.896 A:middle
by the new target will load
on OS X 10.8.Now you're going

00:23:45.896 --> 00:23:49.026 A:middle
to use gdb to debug that one.

00:23:49.026 --> 00:23:52.246 A:middle
That's the divide
between 10.8 and 10.9:

00:23:52.596 --> 00:23:54.456 A:middle
10.8 and earlier is gdb,

00:23:54.806 --> 00:23:58.206 A:middle
10.9 and later is lldb.And
you're going to verify

00:23:58.206 --> 00:23:59.136 A:middle
that that did, in fact,

00:23:59.136 --> 00:23:59.306 A:middle
go

00:23:59.306 --> 00:24:05.026 A:middle
to
/System/Library/Extensions.Since

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00:23:59.306 --> 00:24:05.026 A:middle
to
/System/Library/Extensions.Since

00:24:05.026 --> 00:24:06.986 A:middle
you'll be installing
two kernel extensions,

00:24:07.256 --> 00:24:12.086 A:middle
it might be a good idea if you
were to look at the target OS

00:24:12.086 --> 00:24:15.366 A:middle
in your install scripts, see
what OS you're installing into

00:24:15.366 --> 00:24:17.986 A:middle
and avoid installing the legacy
kext if you're installing

00:24:17.986 --> 00:24:21.666 A:middle
onto a Maverick system, because
it will never need it.And

00:24:21.666 --> 00:24:24.586 A:middle
another warning I'll throw
out here is in the future

00:24:24.586 --> 00:24:27.326 A:middle
as we start to lock
down the /System folder,

00:24:27.676 --> 00:24:29.216 A:middle
you might actually
get write errors.

00:24:29.306 --> 00:24:31.136 A:middle
So when you try to
install a kernel extension

00:24:31.136 --> 00:24:35.236 A:middle
into the /System folder,
the write itself may fail.

00:24:35.336 --> 00:24:37.676 A:middle
Your installer script needs
to be smart enough to know

00:24:37.676 --> 00:24:40.826 A:middle
if it tries to write something
there, as long as the one

00:24:40.826 --> 00:24:41.296 A:middle
that went

00:24:41.296 --> 00:24:43.286 A:middle
into /Library/Extensions
made it okay,

00:24:43.286 --> 00:24:50.566 A:middle
that's good enough.Alright.So
let's expand one more OS

00:24:50.566 --> 00:24:51.176 A:middle
release back.

00:24:51.176 --> 00:24:52.156 A:middle
In this case we're going

00:24:52.156 --> 00:24:56.256 A:middle
to modify the project we
just created for OS X 10.7,

00:24:56.656 --> 00:25:01.306 A:middle
but one difference is we're
going to use Xcode 4.6.

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00:24:56.656 --> 00:25:01.306 A:middle
but one difference is we're
going to use Xcode 4.6.

00:25:01.586 --> 00:25:03.956 A:middle
You can't use Xcode 5 for this

00:25:03.956 --> 00:25:13.636 A:middle
because Xcode 5 doesn't
have the 10.7 SDK.As before,

00:25:13.636 --> 00:25:15.426 A:middle
you're still going to
need that certificate

00:25:15.426 --> 00:25:22.336 A:middle
for signing the Maverick's
kext.We're going to start

00:25:22.336 --> 00:25:25.296 A:middle
with the same project as
last time, but we're going

00:25:25.296 --> 00:25:28.806 A:middle
to show the screenshots
in the older Xcode.

00:25:29.596 --> 00:25:31.246 A:middle
So the second target is going

00:25:31.246 --> 00:25:33.626 A:middle
to have slightly different
settings, particularly

00:25:33.626 --> 00:25:36.316 A:middle
to target OS X 10.7, we have

00:25:36.316 --> 00:25:38.236 A:middle
to add the 32-bit Intel
architecture for that,

00:25:38.616 --> 00:25:39.606 A:middle
for full compatibility.

00:25:40.316 --> 00:25:42.136 A:middle
And the resulting kext
from that target will load

00:25:42.136 --> 00:25:48.656 A:middle
on both OS X 10.7 and
10.8.As before, you're going

00:25:48.656 --> 00:25:50.946 A:middle
to make sure that the
module identifier,

00:25:51.186 --> 00:25:52.976 A:middle
the CFBundleIdentifier
that Jerry talked about,

00:25:52.976 --> 00:25:54.386 A:middle
is the same for both targets.

00:25:55.416 --> 00:25:58.686 A:middle
And you're going to make
sure that the legacy kext,

00:25:58.686 --> 00:26:01.946 A:middle
the one that's installing
in the old path,

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00:25:58.686 --> 00:26:01.946 A:middle
the one that's installing
in the old path,

00:26:01.946 --> 00:26:09.436 A:middle
/System/Library/Extensions,

00:26:09.436 --> 00:26:11.146 A:middle
has the older version
number.Let's go and look

00:26:11.146 --> 00:26:12.116 A:middle
at these build settings.

00:26:12.636 --> 00:26:14.976 A:middle
Again, "Architectures",
you need to make sure

00:26:14.976 --> 00:26:16.106 A:middle
that its standard for this SDK.

00:26:16.106 --> 00:26:19.976 A:middle
So the "Base SDK" is
going to be "OS X 10.7"

00:26:20.096 --> 00:26:22.456 A:middle
and the "Architecture"
is going to be both 32

00:26:22.456 --> 00:26:28.116 A:middle
and 64-bit Intel.And as
before, this target needs

00:26:28.116 --> 00:26:33.466 A:middle
to not sign the kext.In
deployment, again,

00:26:33.466 --> 00:26:35.906 A:middle
/System/Library/Extensions
is where it has to go

00:26:35.906 --> 00:26:38.766 A:middle
for OS X 10.7 and
10.8 to see it.

00:26:39.616 --> 00:26:43.506 A:middle
And the "OS X Deployment
Target" needs to match the SDK

00:26:45.126 --> 00:26:47.756 A:middle
as before.This project
will also build two kexts.

00:26:48.176 --> 00:26:50.716 A:middle
The signed kext is
unchanged, it's exactly

00:26:50.716 --> 00:26:52.276 A:middle
as the previous two examples.

00:26:53.196 --> 00:26:57.316 A:middle
But the unsigned kext should
actually load on both 10.7,

00:26:57.316 --> 00:27:01.416 A:middle
all flavors of 10.7 and all
flavors of 10.8, and you will,

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00:26:57.316 --> 00:27:01.416 A:middle
all flavors of 10.7 and all
flavors of 10.8, and you will,

00:27:01.416 --> 00:27:05.326 A:middle
again, use gdb to debug that.

00:27:06.156 --> 00:27:08.196 A:middle
Oh yeah, and as before,
you're going to want

00:27:08.196 --> 00:27:10.196 A:middle
to install only the
kexts that are necessary.

00:27:10.196 --> 00:27:12.586 A:middle
If you're installing to
a 10.7 or 10.8 system,

00:27:12.766 --> 00:27:14.776 A:middle
you'll install both kexts,
but if you're installing

00:27:14.776 --> 00:27:17.206 A:middle
into an OS X 10.9
system, you only need

00:27:17.206 --> 00:27:21.806 A:middle
to install the signed
kext.What happens if you want

00:27:22.126 --> 00:27:25.576 A:middle
to target releases even
further back than 10.7?

00:27:26.056 --> 00:27:27.246 A:middle
It is possible.

00:27:27.246 --> 00:27:29.266 A:middle
You can't do it from a
single Xcode project,

00:27:29.266 --> 00:27:32.346 A:middle
because there is no single Xcode
that spans that many releases.

00:27:32.456 --> 00:27:36.346 A:middle
So probably the best
approach for you is

00:27:36.346 --> 00:27:38.456 A:middle
to take your existing
kernel extension project

00:27:38.456 --> 00:27:43.806 A:middle
that already runs on OS's
up through 10.8 and just use

00:27:43.806 --> 00:27:45.456 A:middle
that kext as the unsigned
kext that you install

00:27:45.456 --> 00:27:47.796 A:middle
in /System/Library/Extensions.

00:27:48.466 --> 00:27:52.616 A:middle
And then use the
simple OS X 10.9 project

00:27:52.726 --> 00:27:56.206 A:middle
that I described first, and
just import the source code

00:27:56.326 --> 00:27:58.256 A:middle
and build a second kext that
way and that will install

00:27:58.256 --> 00:28:01.086 A:middle
in /Library/Extensions.So
effectively you're kind

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00:27:58.256 --> 00:28:01.086 A:middle
in /Library/Extensions.So
effectively you're kind

00:28:01.086 --> 00:28:04.766 A:middle
of building a line in the
sand between Mavericks

00:28:04.766 --> 00:28:06.256 A:middle
and older operating systems

00:28:06.256 --> 00:28:08.756 A:middle
that didn't use signed kernel
extensions, and so it's kind

00:28:08.756 --> 00:28:12.336 A:middle
of a clean break in the
new kext project and focus

00:28:12.336 --> 00:28:14.056 A:middle
on Mavericks and the future.

00:28:17.516 --> 00:28:21.316 A:middle
So, when you're building for
older OS's, I couldn't go

00:28:21.316 --> 00:28:23.386 A:middle
into all the different
permutations, it really depends

00:28:23.386 --> 00:28:27.916 A:middle
on what OS's you're targeting,
what families you are using

00:28:27.916 --> 00:28:29.166 A:middle
within IOKit and so on as

00:28:29.206 --> 00:28:31.806 A:middle
to exactly what compatibility
you would have.

00:28:32.406 --> 00:28:34.716 A:middle
But you need to follow
the compatibility guidance

00:28:34.716 --> 00:28:36.876 A:middle
that we've released for
previous operating systems

00:28:36.876 --> 00:28:39.446 A:middle
when targeting those, and
again, you're kind of separating

00:28:39.446 --> 00:28:42.546 A:middle
out the 10.9 kext anyway.

00:28:42.546 --> 00:28:45.276 A:middle
So, the compatibility
guidance we've given you

00:28:45.276 --> 00:28:46.386 A:middle
in the past still applies

00:28:46.386 --> 00:28:53.996 A:middle
for the legacy kext.And
always install only the kexts

00:28:54.146 --> 00:28:57.956 A:middle
that are particularly
necessary for the target system

00:28:58.286 --> 00:29:01.836 A:middle
and also make sure that you're
robust against write failures

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00:28:58.286 --> 00:29:01.836 A:middle
and also make sure that you're
robust against write failures

00:29:01.836 --> 00:29:02.686 A:middle
to the /System folder

00:29:02.686 --> 00:29:08.586 A:middle
for future.So this is your handy
pocket guide for compatibility.

00:29:09.186 --> 00:29:13.916 A:middle
The first column here
says, OS X 10.7 and beyond.

00:29:14.546 --> 00:29:16.626 A:middle
Those are all the various
settings you're going to need

00:29:16.626 --> 00:29:17.506 A:middle
and each column further

00:29:17.506 --> 00:29:20.716 A:middle
to the right takes it
further 1 OS release.

00:29:21.446 --> 00:29:25.686 A:middle
This is mostly for the at-home
audience that can freeze frame

00:29:25.686 --> 00:29:28.706 A:middle
on this and very quickly
get all those build settings

00:29:28.746 --> 00:29:32.126 A:middle
that they need.All
right, and with that,

00:29:32.126 --> 00:29:34.186 A:middle
I would like to turn the stage

00:29:34.186 --> 00:29:37.086 A:middle
over to Brian Bechtel
who's going to talk to you

00:29:37.086 --> 00:29:38.766 A:middle
about lldb.Thanks
for your attention.

00:29:39.266 --> 00:29:43.116 A:middle
[ Applause ]

00:29:43.616 --> 00:29:44.356 A:middle
>> Brian Bechtel:
Hello everybody.

00:29:44.686 --> 00:29:45.606 A:middle
I'm Brian Bechtel.

00:29:45.856 --> 00:29:48.166 A:middle
I work in Core OS
doing Panic Triage.

00:29:48.166 --> 00:29:50.486 A:middle
I look at panics
all day and we have,

00:29:51.256 --> 00:29:52.406 A:middle
I know it's a wonderful
job [laughter].

00:29:54.086 --> 00:29:56.506 A:middle
We have a saying in our group.

00:29:58.006 --> 00:30:02.686 A:middle
[Laughter] And it really is true
that after about 10,000 panics,

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00:29:58.006 --> 00:30:02.686 A:middle
[Laughter] And it really is true
that after about 10,000 panics,

00:30:02.686 --> 00:30:06.196 A:middle
there pretty straightforward.

00:30:06.406 --> 00:30:10.626 A:middle
In Mac OS X 10.9 we have
a new debugger, lldb.

00:30:10.626 --> 00:30:15.846 A:middle
It is a very powerful, very
fast, very nice debugger.

00:30:16.516 --> 00:30:17.536 A:middle
It is slightly different.

00:30:17.536 --> 00:30:19.316 A:middle
I'll be talking about
some of those differences.

00:30:19.936 --> 00:30:23.826 A:middle
The big things we get out of
lldb are tighter integration

00:30:23.826 --> 00:30:26.606 A:middle
with llvm and the rest of
the development tool chain.

00:30:27.416 --> 00:30:30.006 A:middle
We have a much, much
faster debugger.

00:30:30.006 --> 00:30:31.486 A:middle
I will be demoing that later.

00:30:32.006 --> 00:30:35.006 A:middle
And we're supporting
it very actively

00:30:35.006 --> 00:30:40.046 A:middle
and we're very much listening
to developer reports of issues

00:30:40.096 --> 00:30:42.266 A:middle
and fixing them, which
is a very good thing.

00:30:44.206 --> 00:30:47.616 A:middle
lldb includes Python as
its scripting language.

00:30:47.616 --> 00:30:50.096 A:middle
That means you can do almost
anything that you can do

00:30:50.096 --> 00:30:53.216 A:middle
in Python inside lldb, it
gives you way more power

00:30:53.526 --> 00:30:55.726 A:middle
than the old macro
language in gdb.

00:30:56.706 --> 00:31:01.916 A:middle
There is a gdb to lldb command
map up on the llvm.org website,

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00:30:56.706 --> 00:31:01.916 A:middle
There is a gdb to lldb command
map up on the llvm.org website,

00:31:01.996 --> 00:31:04.536 A:middle
which helps you make
this transition,

00:31:04.956 --> 00:31:07.486 A:middle
but much of the commands
are exactly the same

00:31:07.486 --> 00:31:09.356 A:middle
for the things you typically do.

00:31:10.096 --> 00:31:15.016 A:middle
lldb is the debugger for
Mac OS X 10.9 and beyond.

00:31:15.646 --> 00:31:16.646 A:middle
gdb is dead.

00:31:18.526 --> 00:31:20.516 A:middle
[Laughter] gdb is
gone in Xcode 5.0.

00:31:20.926 --> 00:31:22.646 A:middle
There is no gdb binary there.

00:31:22.876 --> 00:31:27.086 A:middle
There is no kgmacros file in the
kernel debug kit for Mavericks.

00:31:27.676 --> 00:31:29.966 A:middle
We have no plans to fix
any remaining issues.

00:31:31.406 --> 00:31:34.816 A:middle
It is still the debugger
of choice for Snow Leopard,

00:31:35.056 --> 00:31:38.706 A:middle
the cats basically, if you
have a cat, gdb is your friend.

00:31:39.046 --> 00:31:43.436 A:middle
If you have a giant wave or
some other California feature,

00:31:43.846 --> 00:31:44.866 A:middle
lldb is your friend.

00:31:44.866 --> 00:31:52.066 A:middle
This is a demo of how fast gdb
is, versus how fast lldb is.

00:31:52.516 --> 00:31:54.196 A:middle
I'm just going to
issue one command

00:31:54.196 --> 00:32:00.206 A:middle
in the debugger while connected
via gdb to a 10.8 system

WEBVTT
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00:31:54.196 --> 00:32:00.206 A:middle
in the debugger while connected
via gdb to a 10.8 system

00:32:00.596 --> 00:32:03.216 A:middle
and lldb to a 10.9 system.

00:32:03.996 --> 00:32:06.966 A:middle
I've set up two terminal
windows here,

00:32:06.966 --> 00:32:09.256 A:middle
the light brown one
is running gdb

00:32:09.556 --> 00:32:12.076 A:middle
and the white one
is running lldb.

00:32:12.076 --> 00:32:15.956 A:middle
I'm even going to let gdb
start first so you're going

00:32:15.956 --> 00:32:18.676 A:middle
to see a cursor there
that touches that window,

00:32:18.976 --> 00:32:21.536 A:middle
I hit Return, then go down
and hit the other window.

00:32:22.126 --> 00:32:24.576 A:middle
And what you see
is lldb is much,

00:32:24.576 --> 00:32:27.946 A:middle
much faster at just
printing the zone list.

00:32:29.716 --> 00:32:33.166 A:middle
Every other command in lldb has
this kind of speed improvement.

00:32:33.616 --> 00:32:36.636 A:middle
It's really quite, quite
noticeable, and wonderful

00:32:36.636 --> 00:32:40.136 A:middle
if you're doing 10,000 panics.

00:32:41.406 --> 00:32:44.326 A:middle
[Laughter] All of the standard
kgmacros are still there,

00:32:44.326 --> 00:32:48.486 A:middle
I said there's no kgmacros file,
but the kgmacros themselves,

00:32:48.576 --> 00:32:53.836 A:middle
reimplemented in Python, are
in the mach kernel.dSYM file

00:32:53.836 --> 00:32:55.576 A:middle
in a directory, which
I'll discuss later.

00:32:56.126 --> 00:32:58.356 A:middle
These are all the
standard macros that we use

00:32:58.356 --> 00:33:02.156 A:middle
when we're debugging to just get
the generic information we need

WEBVTT
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00:32:58.356 --> 00:33:02.156 A:middle
when we're debugging to just get
the generic information we need

00:33:02.156 --> 00:33:04.346 A:middle
for a panic.

00:33:04.616 --> 00:33:06.466 A:middle
They're still there, there
are some minor changes

00:33:06.466 --> 00:33:10.306 A:middle
in the output format, but
everything works great.

00:33:11.776 --> 00:33:14.126 A:middle
For adding kext symbols,
on startup,

00:33:14.126 --> 00:33:17.456 A:middle
lldb will automatically
scan for kexts installed

00:33:17.456 --> 00:33:22.676 A:middle
in System/Library/Extensions,
the new Library/Extensions,

00:33:23.206 --> 00:33:26.176 A:middle
and in the directory
/Volumes/Kernel/DebugKit

00:33:26.176 --> 00:33:29.786 A:middle
because that's the kext
symbols that we give you in all

00:33:29.786 --> 00:33:32.206 A:middle
of the symbols for IOKit kexts.

00:33:33.096 --> 00:33:37.666 A:middle
You can specify additional
locations in the .lldbinit file

00:33:37.666 --> 00:33:40.156 A:middle
in your home directory.

00:33:40.156 --> 00:33:41.716 A:middle
There's the command line for it.

00:33:42.276 --> 00:33:44.056 A:middle
And of course while
you're debugging,

00:33:44.126 --> 00:33:47.166 A:middle
you can add kext symbols
using the addkext macro.

00:33:47.446 --> 00:33:52.576 A:middle
I'll have some examples
of that later.

00:33:53.976 --> 00:33:56.456 A:middle
Every time you change something
you'll have little gotchas,

00:33:56.456 --> 00:33:58.246 A:middle
these are some of
the ones that hit me

00:33:58.246 --> 00:34:01.046 A:middle
that I thought you guys
would like to know.

WEBVTT
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00:33:58.246 --> 00:34:01.046 A:middle
that I thought you guys
would like to know.

00:34:01.416 --> 00:34:06.416 A:middle
lldb likes to pretend it
doesn't know how to do addition.

00:34:07.326 --> 00:34:08.666 A:middle
Backtick is your friend.

00:34:08.906 --> 00:34:11.735 A:middle
Backtick, if you get a, if
you try to display something

00:34:12.016 --> 00:34:13.946 A:middle
and it says, "I don't know
what that is that you're trying

00:34:13.946 --> 00:34:16.176 A:middle
to display," put the
expression in backticks.

00:34:16.656 --> 00:34:20.366 A:middle
It sometimes fixes that.

00:34:20.366 --> 00:34:24.396 A:middle
gdb was very, very sloppy
about describing a structure

00:34:24.396 --> 00:34:28.136 A:middle
or a pointer to a structure
or fields in a structure.

00:34:28.186 --> 00:34:30.255 A:middle
lldb is very pedantic about that

00:34:30.286 --> 00:34:33.596 A:middle
because it gets very pedantic
information from llvm.

00:34:33.596 --> 00:34:37.946 A:middle
So if you're saying this is
a pointer to a structure,

00:34:38.466 --> 00:34:40.786 A:middle
you have to say it's a
pointer to a structure,

00:34:40.786 --> 00:34:45.076 A:middle
it'll painfully warn you that
you probably meant to say that

00:34:45.076 --> 00:34:47.726 A:middle
and let you reenter
your command.

00:34:48.696 --> 00:34:51.235 A:middle
And you may need to cast a
variable very explicitly.

00:34:51.235 --> 00:34:55.436 A:middle
We've had issues where you
know that this class is called,

00:34:55.656 --> 00:35:00.436 A:middle
"MyClass," and you say, "Print
MyClass," and instead it says,

WEBVTT
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00:34:55.656 --> 00:35:00.436 A:middle
"MyClass," and you say, "Print
MyClass," and instead it says,

00:35:00.436 --> 00:35:03.456 A:middle
"I don't know what MyClass is,"
but if you say, "Class/MyClass,"

00:35:03.456 --> 00:35:06.496 A:middle
or "Struct/MyStruct," it'll
say, "Yeah sure I can do that."

00:35:07.886 --> 00:35:10.216 A:middle
Anything you encounter like
that, we want to hear about it,

00:35:10.286 --> 00:35:12.866 A:middle
so please go to
bugreporter.apple.com,

00:35:13.216 --> 00:35:16.036 A:middle
file any issues you're
having, we really want

00:35:16.036 --> 00:35:18.256 A:middle
to hear those things, they're
going to the engineers,

00:35:18.566 --> 00:35:22.076 A:middle
they will repair them or
at least have a reason why.

00:35:22.926 --> 00:35:26.396 A:middle
So one of the great things

00:35:26.396 --> 00:35:28.556 A:middle
in lldb is the mixed
mode disassembly.

00:35:28.556 --> 00:35:30.396 A:middle
A lot of times when
you're trying to figure

00:35:30.396 --> 00:35:33.746 A:middle
out what happened, it's
difficult to translate

00:35:33.746 --> 00:35:37.526 A:middle
in your head what is
going on in the assembly

00:35:37.526 --> 00:35:39.346 A:middle
versus what the compiler did.

00:35:40.416 --> 00:35:44.416 A:middle
The disassemble -m option
gives you mixed mode

00:35:44.826 --> 00:35:47.176 A:middle
of whatever you're asking for.

00:35:47.176 --> 00:35:50.166 A:middle
You can say, for instance,
"disassemble -f -m,"

00:35:50.366 --> 00:35:53.726 A:middle
which will disassemble
the entire current frame

00:35:53.726 --> 00:35:56.616 A:middle
with both source and assembly,

00:35:56.826 --> 00:35:58.816 A:middle
intermixed so you can
see where everything is.

00:35:59.306 --> 00:36:01.246 A:middle
If you just want to see the
current line that you're stopped

WEBVTT
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00:35:59.306 --> 00:36:01.246 A:middle
If you just want to see the
current line that you're stopped

00:36:01.246 --> 00:36:03.796 A:middle
on you can say, "disassemble
-l -m

00:36:04.426 --> 00:36:06.716 A:middle
or you can give it
a start and address.

00:36:07.016 --> 00:36:11.966 A:middle
And you can abbreviate that,
the minimum command abbreviation

00:36:11.966 --> 00:36:14.446 A:middle
for disassemble is di.

00:36:14.446 --> 00:36:16.166 A:middle
So you can say di -f -m.

00:36:17.306 --> 00:36:19.846 A:middle
Here's an example of
mixed mode disassembly.

00:36:19.896 --> 00:36:22.996 A:middle
The stupidest, simplest
example I could come up with.

00:36:23.436 --> 00:36:26.556 A:middle
There's a routine in the
kernel called, fseventsf-write,

00:36:27.206 --> 00:36:31.216 A:middle
which just returns
EIO, an error.

00:36:31.866 --> 00:36:36.856 A:middle
So this is the example of
that routine disassembled

00:36:36.856 --> 00:36:39.366 A:middle
with mixed disassembly.

00:36:40.146 --> 00:36:42.766 A:middle
Here you see the
prologue of the routine.

00:36:44.076 --> 00:36:47.846 A:middle
EIO turns out to be the value
of 5, so here it's moving 5

00:36:47.846 --> 00:36:49.136 A:middle
into the return register.

00:36:50.156 --> 00:36:52.456 A:middle
And here you see the epilogue.

00:36:53.436 --> 00:36:55.906 A:middle
So in a much more
complex example,

00:36:55.906 --> 00:36:57.236 A:middle
this is really, really helpful.

00:36:57.596 --> 00:37:07.036 A:middle
Here, you could probably figure
that out in a day or two.

WEBVTT
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00:36:57.596 --> 00:37:07.036 A:middle
Here, you could probably figure
that out in a day or two.

00:37:07.036 --> 00:37:07.103 A:middle
[Laughter]

00:37:07.103 --> 00:37:07.170 A:middle
[ Silence ]

00:37:07.170 --> 00:37:09.756 A:middle
The kgmacros now take
an additional argument,

00:37:09.756 --> 00:37:11.306 A:middle
or series of arguments.

00:37:11.616 --> 00:37:13.516 A:middle
You can now redirect output

00:37:13.516 --> 00:37:16.576 A:middle
from a macro directly
to a file with -o.

00:37:17.396 --> 00:37:21.536 A:middle
If you get a macro that
has a lot of output

00:37:21.536 --> 00:37:22.926 A:middle
and you don't want
all that output,

00:37:22.926 --> 00:37:26.206 A:middle
you can grep inside
the output with -s

00:37:26.936 --> 00:37:30.126 A:middle
and you can add additional
verbosity to the macros

00:37:30.126 --> 00:37:35.306 A:middle
to see additional details
about the macro with -v and it,

00:37:35.306 --> 00:37:41.996 A:middle
it is cumulative so you can
say -v -v -v, you can be anal

00:37:41.996 --> 00:37:43.376 A:middle
and see how far out you can go.

00:37:44.366 --> 00:37:45.696 A:middle
So here's an example,

00:37:45.696 --> 00:37:47.806 A:middle
if you want to find
the load information

00:37:47.806 --> 00:37:52.696 A:middle
for just our sample PCI kext,
you can say, 'showallkmods,"

00:37:52.696 --> 00:37:55.696 A:middle
which shows all of
the kext information,

00:37:56.056 --> 00:38:01.036 A:middle
and then say -s AppleSamplePCI
to just get the information

WEBVTT
X-TIMESTAMP-MAP=MPEGTS:181083,LOCAL:00:00:00.000

00:37:56.056 --> 00:38:01.036 A:middle
and then say -s AppleSamplePCI
to just get the information

00:38:01.036 --> 00:38:03.966 A:middle
on one line rather than have to
scroll through a lot of lines.

00:38:06.286 --> 00:38:11.586 A:middle
For security purposes, we do
not automatically load the lldb

00:38:11.586 --> 00:38:14.006 A:middle
macros in lldb by default.

00:38:14.836 --> 00:38:15.976 A:middle
The reason we do this is

00:38:15.976 --> 00:38:17.676 A:middle
if you're doing application
debugging

00:38:17.676 --> 00:38:19.406 A:middle
or you have a malicious kext,

00:38:19.826 --> 00:38:23.686 A:middle
and they've put some bad lldb
macros in a hidden symbol file

00:38:23.686 --> 00:38:26.226 A:middle
or something, bad
things could happen.

00:38:26.466 --> 00:38:28.176 A:middle
You know? It's the
internet nowadays.

00:38:28.966 --> 00:38:31.926 A:middle
So to overcome this because
you trust your development

00:38:31.926 --> 00:38:33.226 A:middle
environment and your setup,

00:38:33.496 --> 00:38:36.216 A:middle
you can add that
particular setting line

00:38:36.216 --> 00:38:39.786 A:middle
to your .lldbinit file and then
it will automatically load the

00:38:39.786 --> 00:38:41.306 A:middle
script from the symbol files.

00:38:41.896 --> 00:38:46.336 A:middle
You can also create custom
Python and put it in the,

00:38:47.506 --> 00:38:48.896 A:middle
in the dSYM file

00:38:48.896 --> 00:38:51.666 A:middle
in the Contents/Resources/Python
directory,

00:38:52.216 --> 00:38:54.406 A:middle
and then that will be
automatically loaded assuming

00:38:54.406 --> 00:38:56.766 A:middle
that you have your
settings set correctly.

00:38:59.316 --> 00:39:01.876 A:middle
For faster loading, a lot
of times you only want

WEBVTT
X-TIMESTAMP-MAP=MPEGTS:181083,LOCAL:00:00:00.000

00:38:59.316 --> 00:39:01.876 A:middle
For faster loading, a lot
of times you only want

00:39:01.876 --> 00:39:03.946 A:middle
to see your particular
kexts, you don't care

00:39:03.946 --> 00:39:05.396 A:middle
about Apple's kexts,
you don't care

00:39:05.396 --> 00:39:06.586 A:middle
about all those other things.

00:39:07.666 --> 00:39:11.306 A:middle
Add this line before you
do the connection or put

00:39:11.306 --> 00:39:13.346 A:middle
that in your .lldbinit file

00:39:13.766 --> 00:39:15.366 A:middle
and it won't load
all the other things

00:39:15.366 --> 00:39:18.516 A:middle
and you just come right
back up to Ready To Go.

00:39:18.566 --> 00:39:21.436 A:middle
And then at that point if you
want to automatically load,

00:39:21.436 --> 00:39:25.506 A:middle
or manually load symbols for
your kext, you can use any

00:39:25.506 --> 00:39:28.536 A:middle
of these four examples
of the addkext command.

00:39:28.926 --> 00:39:32.166 A:middle
You can either pass it
the UUID, pass it the name

00:39:32.166 --> 00:39:34.856 A:middle
and if the name is found
in one of the places

00:39:34.856 --> 00:39:37.396 A:middle
that lldb searches,
it will load it.

00:39:37.786 --> 00:39:40.166 A:middle
You can give it an
explicit path, an address,

00:39:40.576 --> 00:39:43.596 A:middle
or you can say, "Hey, I changed
my mind I want them all loaded,"

00:39:43.986 --> 00:39:45.716 A:middle
that will take a lot
longer than it would

00:39:45.716 --> 00:39:52.496 A:middle
if you'd just let lldb
do it at the beginning.

00:39:52.496 --> 00:39:54.886 A:middle
nvram is needed, I'm
going to now be talking

00:39:54.886 --> 00:39:56.106 A:middle
about two machine debugging.

00:39:56.746 --> 00:40:00.546 A:middle
We use nvram to enable
debugging at all.

WEBVTT
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00:39:56.746 --> 00:40:00.546 A:middle
We use nvram to enable
debugging at all.

00:40:01.056 --> 00:40:03.376 A:middle
If you have no debug
boot argument set,

00:40:03.646 --> 00:40:05.596 A:middle
your system will
reboot on panic,

00:40:05.686 --> 00:40:08.156 A:middle
that's a new behavior
starting in 10.8.

00:40:09.146 --> 00:40:13.596 A:middle
If you set boot-args using the
nvram command line tool as root

00:40:14.036 --> 00:40:17.376 A:middle
and reboot to let those settings
take effect, you can change

00:40:17.376 --> 00:40:19.546 A:middle
that behavior so
you'll halt at panic

00:40:19.936 --> 00:40:22.206 A:middle
and let you connect
from another machine.

00:40:23.556 --> 00:40:30.326 A:middle
So in the old days, back when
we had just iMac's or something,

00:40:30.756 --> 00:40:32.816 A:middle
we had built-in Ethernet
and built-in FireWire.

00:40:33.166 --> 00:40:37.066 A:middle
Nowadays, probably most of you
out there, have a MacBook Air

00:40:37.066 --> 00:40:41.556 A:middle
or something that no longer has
built-in Ethernet nor built-in

00:40:41.556 --> 00:40:44.826 A:middle
FireWire, so we've added
new ways to connect.

00:40:44.916 --> 00:40:48.866 A:middle
You can now connect for two
machine debugging using a

00:40:48.866 --> 00:40:51.846 A:middle
Thunderbolt Ethernet
Adaptor, using a Thunderbolt

00:40:51.846 --> 00:40:55.946 A:middle
to FireWire Adaptor, using
an Apple Thunderbolt display

00:40:55.946 --> 00:40:59.216 A:middle
in either Ethernet or FireWire
on the back of that monitor.

00:40:59.806 --> 00:41:03.616 A:middle
We do not support wireless and
we do not support USB Ethernet,

WEBVTT
X-TIMESTAMP-MAP=MPEGTS:181083,LOCAL:00:00:00.000

00:40:59.806 --> 00:41:03.616 A:middle
We do not support wireless and
we do not support USB Ethernet,

00:41:04.016 --> 00:41:06.336 A:middle
so you're going to have to get
one of those other connections.

00:41:08.986 --> 00:41:13.626 A:middle
When you connect, two-machine
debugging assumes a network port

00:41:13.626 --> 00:41:18.886 A:middle
of en0, that's the old
behavior from the original iMac,

00:41:18.886 --> 00:41:21.166 A:middle
MacBook Pro, Mac Pro, whatever.

00:41:21.816 --> 00:41:26.056 A:middle
If your network port isn't
that, you have to add,

00:41:26.056 --> 00:41:27.556 A:middle
as part of your boot arguments,

00:41:27.936 --> 00:41:30.906 A:middle
kdp-match-name=,
and then some value.

00:41:31.816 --> 00:41:34.246 A:middle
That some value will
depend on your connection.

00:41:34.626 --> 00:41:37.366 A:middle
For a network connection,
ifconfig, will tell you

00:41:37.366 --> 00:41:38.826 A:middle
which port you should use.

00:41:39.216 --> 00:41:40.486 A:middle
So if you have a Thunderbolt

00:41:40.486 --> 00:41:43.796 A:middle
to Ethernet connector
you would use ifconfig

00:41:43.796 --> 00:41:48.826 A:middle
to find the connection and
then kdp-match-name=en whatever

00:41:48.826 --> 00:41:49.716 A:middle
that number is.

00:41:50.316 --> 00:41:51.816 A:middle
Here's an example of that.

00:41:51.816 --> 00:41:56.136 A:middle
This is the output from the
ifconfig command just cut

00:41:56.136 --> 00:41:57.726 A:middle
down to a single port.

00:41:58.996 --> 00:42:02.576 A:middle
I'm looking for a port with an
inet value that makes sense.

WEBVTT
X-TIMESTAMP-MAP=MPEGTS:181083,LOCAL:00:00:00.000

00:41:58.996 --> 00:42:02.576 A:middle
I'm looking for a port with an
inet value that makes sense.

00:42:02.896 --> 00:42:07.136 A:middle
So, for instance, here
at the conference,

00:42:07.466 --> 00:42:11.066 A:middle
we're running off the
10.0 net or 10.1 net,

00:42:11.146 --> 00:42:12.366 A:middle
I'm not sure which one.

00:42:12.996 --> 00:42:15.856 A:middle
I look for a connection
that's 10.

00:42:15.856 --> 00:42:19.346 A:middle
whatever, the en1
tells me that the port

00:42:19.396 --> 00:42:23.106 A:middle
that I will be using
in kdp-match-name=.

00:42:24.796 --> 00:42:30.396 A:middle
So for built-in debugging on
a machine like a MacBook Pro

00:42:30.396 --> 00:42:34.106 A:middle
with built-in Ethernet, you
would just set your boot args

00:42:34.216 --> 00:42:43.066 A:middle
as this: debug=0x144, the
100-bit means don't put

00:42:43.066 --> 00:42:46.556 A:middle
up the graphic panic
screen, just halt.

00:42:47.116 --> 00:42:50.836 A:middle
The 4-bit means let me
connect to the machine,

00:42:51.386 --> 00:42:54.896 A:middle
and the 40-bit means
let me connect

00:42:54.896 --> 00:42:56.946 A:middle
over a different
subnet if necessary.

00:42:57.286 --> 00:43:00.716 A:middle
So you can simplify this to
104 instead if you wanted.

WEBVTT
X-TIMESTAMP-MAP=MPEGTS:181083,LOCAL:00:00:00.000

00:42:57.286 --> 00:43:00.716 A:middle
So you can simplify this to
104 instead if you wanted.

00:43:02.216 --> 00:43:05.086 A:middle
For Thunderbolt to
Ethernet, you'll notice

00:43:05.086 --> 00:43:09.416 A:middle
that same command line
has added kdp-match-name=

00:43:09.416 --> 00:43:10.906 A:middle
and then an en value.

00:43:11.586 --> 00:43:14.646 A:middle
And for Thunderbolt Display,
you would do the same thing.

00:43:15.086 --> 00:43:17.466 A:middle
I'm giving examples
here with en2 and en4,

00:43:17.466 --> 00:43:22.066 A:middle
but you actually need the
output from ifconfig to figure

00:43:22.066 --> 00:43:26.736 A:middle
out what the proper en value
is, and you would put that in.

00:43:27.086 --> 00:43:30.566 A:middle
Many times this value may
coincidentally be there,

00:43:30.566 --> 00:43:34.306 A:middle
and it may be the right value,
but you have to use ifconfig,

00:43:34.346 --> 00:43:36.586 A:middle
you can't just trust a
slide at a conference.

00:43:39.546 --> 00:43:41.166 A:middle
[Laughing] If you're
using native FireWire,

00:43:42.036 --> 00:43:44.946 A:middle
you set kdp-match-name
to FireWire.

00:43:46.116 --> 00:43:49.346 A:middle
If you're using Thunderbolt
FireWire Connector

00:43:49.436 --> 00:43:51.686 A:middle
or Apple Thunderbolt
Display to FireWire,

00:43:52.226 --> 00:43:57.416 A:middle
you have to add an additional
command, which is fwkdp=8000hex.

00:43:57.976 --> 00:44:02.156 A:middle
That tells the Thunderbolt
System not to turn off power

WEBVTT
X-TIMESTAMP-MAP=MPEGTS:181083,LOCAL:00:00:00.000

00:43:57.976 --> 00:44:02.156 A:middle
That tells the Thunderbolt
System not to turn off power

00:44:02.156 --> 00:44:05.376 A:middle
to the FireWire chip, which
would be rather inconvenient

00:44:05.376 --> 00:44:06.426 A:middle
when you're trying to connect.

00:44:07.706 --> 00:44:09.306 A:middle
And as always, you
need to reboot

00:44:09.306 --> 00:44:10.816 A:middle
to let the settings take effect.

00:44:11.426 --> 00:44:15.296 A:middle
So for FireWire debugging
it's very simple,

00:44:15.296 --> 00:44:17.206 A:middle
you open up two terminal
windows.

00:44:17.576 --> 00:44:20.346 A:middle
In one terminal window,
you enter fwkdp,

00:44:20.346 --> 00:44:24.596 A:middle
in the other terminal
window you invoke lldb,

00:44:25.026 --> 00:44:27.846 A:middle
and then connect
to the local host.

00:44:27.846 --> 00:44:31.796 A:middle
The fwkdp is a redirecting
program that makes it look

00:44:31.796 --> 00:44:34.176 A:middle
as if your local
machine is panicked,

00:44:34.546 --> 00:44:38.396 A:middle
but it actually redirects the
commands out the FireWire port

00:44:38.766 --> 00:44:40.166 A:middle
to the panicked machine.

00:44:44.036 --> 00:44:46.796 A:middle
It's important to note
I used xcrun there.

00:44:46.796 --> 00:44:48.486 A:middle
xcrun guarantees
that you're going

00:44:48.486 --> 00:44:52.006 A:middle
to be running the lldb
that's in your current Xcode.

00:44:52.476 --> 00:44:55.766 A:middle
You want that because who knows
what horrible thing you've got

00:44:56.006 --> 00:44:59.166 A:middle
installed in /usr/bin
or /usr/local/bin

00:44:59.606 --> 00:45:01.376 A:middle
that might accidentally
be grabbed.

WEBVTT
X-TIMESTAMP-MAP=MPEGTS:181083,LOCAL:00:00:00.000

00:44:59.606 --> 00:45:01.376 A:middle
that might accidentally
be grabbed.

00:45:01.716 --> 00:45:06.626 A:middle
If you use xcrun lldb it will
always find the proper lldb

00:45:06.626 --> 00:45:07.686 A:middle
for your Xcode.

00:45:08.756 --> 00:45:12.066 A:middle
And I'm giving a couple examples
of how you connect to a machine.

00:45:12.066 --> 00:45:13.256 A:middle
If you're connecting live,

00:45:13.626 --> 00:45:16.276 A:middle
you can either give a
name or an IP address.

00:45:17.056 --> 00:45:19.686 A:middle
You can use a Bonjour name
although there is a warning

00:45:19.686 --> 00:45:24.926 A:middle
that with Bonjour you may have
a reassignment of an address

00:45:25.376 --> 00:45:27.736 A:middle
as you're going along,
so that's a little shaky.

00:45:27.736 --> 00:45:30.786 A:middle
I tend to either use a
fully-qualified domain name

00:45:30.786 --> 00:45:33.046 A:middle
or a dotted IP address.

00:45:33.676 --> 00:45:37.466 A:middle
And if you're reading a coredump
file, the command is "file --

00:45:37.906 --> 00:45:42.736 A:middle
c" and then a path to the file.

00:45:43.876 --> 00:45:47.346 A:middle
In fact, talking about
coredumps, I'm going to talk

00:45:47.346 --> 00:45:51.626 A:middle
about several things that
we've changed recently

00:45:51.626 --> 00:45:53.086 A:middle
that are helpful for you.

00:45:53.086 --> 00:45:57.756 A:middle
The first thing that you'll
notice is we've changed how you

00:45:57.756 --> 00:46:00.366 A:middle
do a NMI in Mac OS X 10.9.

WEBVTT
X-TIMESTAMP-MAP=MPEGTS:181083,LOCAL:00:00:00.000

00:45:57.756 --> 00:46:00.366 A:middle
do a NMI in Mac OS X 10.9.

00:46:01.056 --> 00:46:04.756 A:middle
With boot-args set
so that the 0x4 bit

00:46:04.756 --> 00:46:10.766 A:middle
or the DB-NMI bit is
set, in 10.8 or earlier,

00:46:10.846 --> 00:46:12.306 A:middle
you'd just hit the Power key.

00:46:12.876 --> 00:46:15.236 A:middle
Anybody who's done
kernel debugging

00:46:15.236 --> 00:46:17.556 A:middle
and hit the Power key will
discover that the Power key

00:46:17.556 --> 00:46:21.616 A:middle
on a MacBook Air is directly
next to the Delete key.

00:46:22.226 --> 00:46:24.816 A:middle
And then you curse and
reboot your machine

00:46:24.816 --> 00:46:27.196 A:middle
because you didn't have
it setup for debugging.

00:46:27.656 --> 00:46:30.286 A:middle
So we changed that in Mavericks.

00:46:30.506 --> 00:46:34.126 A:middle
Now it is Left and Right
command keys and the Power key.

00:46:34.876 --> 00:46:37.486 A:middle
This will make your
day-to-day life a lot easier.

00:46:38.706 --> 00:46:41.036 A:middle
If you really like the old
behavior, you can revert to that

00:46:41.326 --> 00:46:43.516 A:middle
by OR'ing [phonetic]
in the hex 8000-bit,

00:46:43.996 --> 00:46:49.396 A:middle
so instead of debug=0x144,
you'd say debug=8144.

00:46:50.776 --> 00:46:54.536 A:middle
You can automatically
save coredumps.

00:46:54.586 --> 00:46:58.436 A:middle
This works far back in the
system, but I'm documenting it

00:46:58.436 --> 00:46:59.666 A:middle
to make sure everybody has it

00:46:59.666 --> 00:47:01.936 A:middle
because it's a pretty
easy process.

WEBVTT
X-TIMESTAMP-MAP=MPEGTS:181083,LOCAL:00:00:00.000

00:46:59.666 --> 00:47:01.936 A:middle
because it's a pretty
easy process.

00:47:02.746 --> 00:47:05.636 A:middle
As root on a host machine,
the machine where you're going

00:47:05.636 --> 00:47:07.456 A:middle
to save the coredump, you need

00:47:07.456 --> 00:47:09.526 A:middle
to create a directory
called PanicDumps,

00:47:10.436 --> 00:47:17.456 A:middle
change it to permissions, and
then launch the kdump.plist,

00:47:17.456 --> 00:47:20.826 A:middle
which will load a demon that
will sit there waiting to see

00:47:20.826 --> 00:47:23.206 A:middle
if anybody wants to send
it a coredump to save.

00:47:24.006 --> 00:47:26.836 A:middle
On the client machine, on the
machine that you want to panic

00:47:26.836 --> 00:47:30.736 A:middle
and save a core from, you
can set your boot-args

00:47:31.056 --> 00:47:39.116 A:middle
where debug is 0xd44 panicd ip=

00:47:39.386 --> 00:47:42.776 A:middle
and then the dotted IP
address of the host machine.

00:47:43.126 --> 00:47:46.166 A:middle
It has to be a dotted IP
address because at the time

00:47:46.166 --> 00:47:48.386 A:middle
of a panic we can't
do DNS resolution.

00:47:48.996 --> 00:47:55.016 A:middle
We've added some new
protection boot-args,

00:47:55.076 --> 00:47:58.676 A:middle
which will help you track
down buffer overruns,

00:47:58.676 --> 00:48:02.336 A:middle
use after free errors,
mismatched frees, you know,

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00:47:58.676 --> 00:48:02.336 A:middle
use after free errors,
mismatched frees, you know,

00:48:02.536 --> 00:48:05.056 A:middle
freeing from a zone that you
didn't actually allocate from,

00:48:05.546 --> 00:48:07.346 A:middle
and some timing-induced races.

00:48:08.056 --> 00:48:14.826 A:middle
-zc, the allocate code inside
the kernel for zone allocations,

00:48:15.246 --> 00:48:17.366 A:middle
checks the free-list
pointers of all the zones

00:48:17.366 --> 00:48:20.496 A:middle
for correctness every
time you do an allocation.

00:48:20.496 --> 00:48:25.776 A:middle
-zp, the free routine,
will overwrite freed memory

00:48:25.776 --> 00:48:27.226 A:middle
with deadbeefdeadbeef.

00:48:27.716 --> 00:48:31.856 A:middle
That will catch any attempt to
execute or access freed data.

00:48:31.856 --> 00:48:36.856 A:middle
And here's an example of how
you would set that: debug=144,

00:48:36.856 --> 00:48:41.376 A:middle
for the two-machine debugging,
-zp -zc, and of course reboot

00:48:41.426 --> 00:48:44.486 A:middle
to let it take effect.

00:48:44.666 --> 00:48:47.486 A:middle
We also have a guard mode
kernel zone allocator.

00:48:47.616 --> 00:48:51.916 A:middle
This will let you target
any zone with a certain size

00:48:51.916 --> 00:48:55.736 A:middle
or any zone above a certain
size, below a certain size,

00:48:55.736 --> 00:48:57.216 A:middle
or in a range of sizes.

00:48:57.926 --> 00:49:02.436 A:middle
You set, specify one of
gzalloc-size, gzalloc-min,

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00:48:57.926 --> 00:49:02.436 A:middle
You set, specify one of
gzalloc-size, gzalloc-min,

00:49:02.776 --> 00:49:07.556 A:middle
gzalloc-max, or min and
max, and then gzalloc-wp.

00:49:07.556 --> 00:49:11.816 A:middle
And that will write-protect
the allocations rather

00:49:11.816 --> 00:49:14.456 A:middle
than unmapping them.

00:49:14.896 --> 00:49:17.716 A:middle
So the allocation
will still be around,

00:49:18.116 --> 00:49:21.176 A:middle
but it will be write-protected.

00:49:21.716 --> 00:49:29.026 A:middle
Zp and zc aren't very much
of an impact on performance,

00:49:29.026 --> 00:49:30.966 A:middle
I wouldn't do your
benchmarking with them set.

00:49:31.456 --> 00:49:34.346 A:middle
But they don't really
take up too much memory

00:49:34.346 --> 00:49:36.386 A:middle
and they don't really
take up too much time

00:49:36.726 --> 00:49:38.146 A:middle
in the allocation and free.

00:49:38.986 --> 00:49:43.956 A:middle
The gzalloc-wp, gzalloc-size
stuff, every allocation is going

00:49:43.956 --> 00:49:47.176 A:middle
to be put on its own 4k page
with an additional guard page,

00:49:48.086 --> 00:49:49.756 A:middle
measurably slower,
you'll notice it

00:49:49.756 --> 00:49:52.456 A:middle
when you're using the machine,
but it catches all kinds

00:49:52.456 --> 00:49:55.816 A:middle
of bugs, it's a very
valuable tool.

00:49:56.686 --> 00:49:59.236 A:middle
Another point I wanted
to make is that starting

00:49:59.236 --> 00:50:03.746 A:middle
in Mac OS X 10.8,
we changed graphics

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00:49:59.236 --> 00:50:03.746 A:middle
in Mac OS X 10.8,
we changed graphics

00:50:03.746 --> 00:50:05.356 A:middle
to support multiple buffers.

00:50:05.776 --> 00:50:08.696 A:middle
We draw the console output
tool buffer in instead

00:50:08.696 --> 00:50:09.996 A:middle
of directly to the screen.

00:50:10.486 --> 00:50:12.596 A:middle
This was an enhancement
needed in order

00:50:12.596 --> 00:50:15.426 A:middle
to support the retina
display Macs, but it applies

00:50:15.426 --> 00:50:16.726 A:middle
across all the machines.

00:50:17.136 --> 00:50:20.206 A:middle
Unfortunately, that means you
have unreliable console output

00:50:20.206 --> 00:50:22.016 A:middle
to the screen if you panic.

00:50:22.386 --> 00:50:26.066 A:middle
So if you have your boot-args
set to display text instead

00:50:26.066 --> 00:50:29.066 A:middle
of a panic screen, you
may not see that text,

00:50:29.066 --> 00:50:30.076 A:middle
it will appear to hang.

00:50:30.076 --> 00:50:32.016 A:middle
The only way to tell
is to attempt

00:50:32.016 --> 00:50:33.156 A:middle
to connect to the machine.

00:50:35.076 --> 00:50:38.116 A:middle
For more information
about all of this,

00:50:38.116 --> 00:50:41.386 A:middle
we have documentation
online, we have a contact here

00:50:41.386 --> 00:50:42.896 A:middle
from the evangelist group,

00:50:43.346 --> 00:50:47.796 A:middle
and the developer forums
are actually get pretty good

00:50:47.796 --> 00:50:50.046 A:middle
coverage from people
inside of Apple.

00:50:51.036 --> 00:50:53.706 A:middle
I recommend understanding
and debugging kernel panics.

00:50:53.966 --> 00:50:56.586 A:middle
The Kernel Core Dumps,
I specified all

00:50:56.586 --> 00:50:59.316 A:middle
of the stuff you need from
Kernel Core Dumps on one slide.

00:50:59.576 --> 00:51:00.866 A:middle
So, it's not very difficult.

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00:50:59.576 --> 00:51:00.866 A:middle
So, it's not very difficult.

00:51:01.236 --> 00:51:03.666 A:middle
And there's a new revision

00:51:03.666 --> 00:51:05.836 A:middle
to the generating a
non-maskable interrupt,

00:51:06.216 --> 00:51:09.106 A:middle
which is in the Mavericks
section

00:51:09.106 --> 00:51:13.696 A:middle
of the developer website,
the original version

00:51:13.696 --> 00:51:15.226 A:middle
of that is referenced here.

00:51:15.226 --> 00:51:19.876 A:middle
We have some related
sessions later this week,

00:51:19.946 --> 00:51:23.466 A:middle
on Friday in the Pacific
Heights Conference Room,

00:51:23.466 --> 00:51:27.496 A:middle
they'll be an Advanced Debugging
with LLDB, I recommend you go.

00:51:28.256 --> 00:51:31.636 A:middle
So in summary, sign
your kexts in 10.9.

00:51:31.936 --> 00:51:33.336 A:middle
We've had two people
tell you that,

00:51:33.336 --> 00:51:35.166 A:middle
it's the wave of the future.

00:51:35.936 --> 00:51:37.566 A:middle
lldb is actually pretty cool.

00:51:37.726 --> 00:51:38.276 A:middle
I like it.

00:51:38.276 --> 00:51:41.616 A:middle
I prefer it over gdb
now that I'm used to it.

00:51:41.806 --> 00:51:44.856 A:middle
Like any new technology,
it takes a bit to get used,

00:51:44.946 --> 00:51:47.686 A:middle
but it's very powerful
and very nice.

00:51:48.606 --> 00:51:51.056 A:middle
We have new ways of
debugging for machines

00:51:51.276 --> 00:51:53.916 A:middle
that do not have built-in
FireWire or built-in Ethernet,

00:51:54.386 --> 00:51:56.836 A:middle
and we have new boot-args
that help you track down bugs.

00:51:58.896 --> 00:52:00.766 A:middle
There you go.

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00:51:58.896 --> 00:52:00.766 A:middle
There you go.

00:52:01.266 --> 00:52:22.480 A:middle
[ Applause ]