Inspect Running Mac OS X Applications with F-Script

Objective C is a Dynamic Runtime, so you can load code like plugins during runtime. This dynamic runtime can be very useful for exploring what applications are doing. I use this to assess the security of applications for example.

F-Script provides an easy way to inject itself into a running app and explore around.

Download F-Script here

Launch the app you want to explore.

Then find the process id number of the app in a Terminal shell:

ps auxww | grep “App Name

Load the F-Script Framework into the app and insert its menu using:

sudo gdb --pid AppNameProcessID --batch --nx --command=/dev/stdin << EOT
p (char)[[NSBundle bundleWithPath:@"path/to/Library/Frameworks/FScript.framework"] load]
p (void)[FScriptMenuItem insertInMainMenu]

I found the above snippet by reviewing this automator service.

Note that sudo is only required if you are not in the _developer group.

At this point, switch to your running application.  You will notice an F-Script Menu is added to the menu bar.

Choose Console from the F-Script menu and type:

del := NSApplication sharedApplication delegate

This will give you a reference to the application delegate.  The application delegate is a top level class of the application, so it should provide a good starting point.

Next, choose Open Object Browser from the F-Script menu.

Now you should have a nice GUI window to explore the app.

Click on del in the Workspace to explore the app delegate.  You can call methods, change values, etc.

See the F-Script documentation for more details.


MIME type issue with Apache mod_jk and mod_proxy serving plain text

Some apps do not properly set mime types of content they serve, but still may work properly when served standalone because client applications like browsers are able to interpret the type of the content.  But when served behind Apache, these apps will not behave correctly because Apache will provide a default type of text/plain.

The solution is to add a DefaultType None line to your apache virtual host for these web apps:

DefaultType None

Here are the docs

Snow Leopard Apache Web Server SSL Pass phrase Error

If you are getting errors “Pass phrase incorrect” in your apache logs on Snow Leopard server, it is because the key is protected by a password.  I found the answer here.

The password for the key is stored in the System Keychain.  It is a password entry called “Mac OS X Server certificate management”.  You can open the entry and select “Show Password”.  You may also use the security command line tool to dump the password.

security find-generic-password -l "Mac OS X Server certificate management" -g


security dump-keychain -d # look in data for password which will look like a GUID

Once you have the password, you can create a copy of the key without the password using openssl:

openssl rsa -in /etc/certificates/ \
 -out /etc/certificates/

You can then replace the password protected key with the passwordless key or point apache to the passwordless key in your /etc/apache2/sites/sitename.conf file.