Controlling Multiple launchagents and launchdaemons concurrently

Most of my examples for launchctl have been per-user, per-agent, per-daemon. But you can also control multiple launchctl targets concurrently. One example would be that you can unload everything in the user domain by not specifying a path but providing the userid. In the following example, we’ll just use $userid as a variable, but it’s worth noting that that would be, as an example, 501 for the :

sudo launchctl bootout gui/$userid

There’s another option that can be used to do the opposite from within single user mode, called bootshell. Bootshell is called similarly from single user mode:

sudo launchctl bootshell

Device Snapshots and Crafting A Restore Device User Experience for Macs

I recently worked on something where a design requirement was to build a good snapshot restore option but not to use Time Machine backups. You can capture a snapshot of a Mac without enabling Time Machine. To do so, you’d still use the same binary as you would with Time Machine, /usr/bin/tmutil. To do so, simply use the snapshot verb as follows:

/usr/bin/tmutil snapshot

Once you’ve run that, you get output similar to the following:

Created local snapshot with date: 2019-04-12-110248

Now you have a snapshot that can be used to restore a Mac using the steps shown in this article: https://maclovin.org/blog-native/2017/restoring-from-a-snapshot-with-apfs.

You can make a snapshot at the provisioning time of a Mac and then see that snapshot at any point by awking for the first line in a list of snapshots, unless it’s been deleted:

snapshot=`tmutil listlocalsnapshots / | awk -F "." '{print $4}' | head -1`

Now when it comes to making it simple for end user restores, there’s a few gaps. The first is that you have to boot with Command-R and can’t build a scripted restore option. So the following won’t work on a machine with SIP:

sudo nvram boot-args="-x"; restart

You can prune the list of snapshots so it’s simple for a user to pick the right one though. To see a list of all your snapshots for the current boot volume, use that listlocalsnapshots verb:

tmutil listlocalsnapshots /

This provides the output as com.apple.TimeMachine.2019-04-12-110248 and when deleting snapshots you don’t need the com.apple.TimeMachine. portion of that string, so to delete the last snapshot we’ll gather it into a variable with the following:

snapshot=`tmutil listlocalsnapshots / | awk -F "." '{print $4}' | tail -1`

Alternatively you can list snapshots with the diskutil command, using the apfs option and listSnapshots verb, followed by your boot volume as follows, but the output isn’t pretty:

diskutil apfs listSnapshots disk1s1

Once you’ve parsed the service name portion out, you can then delete a given snapshot using the deletelocalsnapshots verb with tmutil:

tmutil deletelocalsnapshots 2019-04-12-110248

Or to use that snapshot variable:

tmutil deletelocalsnapshots $snapshot

So I can present the user, when they try to revert, with a shorter list of snapshots, hopefully helping them to select the right one. But, I can only do a scripted restore if I’m actually using Time Machine and I have a volume taking those backups. If I’m doing a snapshot restore I have to restart the Mac holding down the command- R keys and then once booted in recovery mode, select the snapshot and wait for the restore.

Booting into recovery mode takes a long time so seems like something you’d teach the desktop techs to do rather than expect users to do a-la-“Erase all Contents and Settings” button. The whole process takes about 20 minutes because of how long it takes to boot into this state and revert.

It’s actually just as quick to do a full reinstallation. This can be as simple as using the startosinstall --eraseinstall command, which provides a number of options. It seems silly to load up a whole new operating system when you have one there, but assuming you have decent internet speeds, it’s just as fast to do so. There’s even a gui wrapper for it to make the whole process easier for your users at https://scriptingosx.com/2018/10/eraseinstall-application/ which could then be provided in tools like Managed Software Center and Self Service. You could also try and remove all user and app data using a script but that has turned out to be a lot of moving parts that requires constant updates.

If you were to opt into a snapshot-based restore option, it’s also worth noting that if you have outdated certificates, outdated passwords, outdated software, etc, that it can be problematic. So we’re pretty much right back to erase-install.

Other people have gone down this same rabbit hole:

  • https://grahamrpugh.com/2018/03/26/reinstall-macos-from-system-volume.html
  • https://www.jamf.com/jamf-nation/discussions/26716/summer-2018-wiping-student-systems

So my initial goal was to create an article on doing an elegant restore process for the Mac, where you script more of it and provide a better experience. But alas, I have failed ya’. Sorry. Do you have a better way? If so, please comment!

Frameworks

A framework is a type of bundle that packages dynamic shared libraries with the resources that the library requires, including files (nibs and images), localized strings, header files, and maybe documentation. The .framework is an Apple structure that contains all of the files that make up a framework.

Frameworks are stored in the following location (where the * is the name of an app or framework):

  • /Applications/*contents/Frameworks
  • /Library/*/
  • /Library/Application Support/*/*.app/Contents/
  • /Library/Developer/CommandLineTools/
  • /Library/Developer/
  • /Library/Frameworks
  • /Library/Printers/
  • /System/iOSSupport/System/Library/PrivateFrameworks
  • /System/iOSSupport/System/Library/Frameworks
  • /System/Library/CoreServices
  • /System/Library/Frameworks
  • /System/Library/PrivateFrameworks
  • /usr/local/Frameworks 

If you just browse through these directories, you’ll see so many things you can use in apps. You can easily add an import followed by the name in your view controllers in Swift. For example, in /System/Library/Frameworks you’ll find the Foundation.framework. Foundation is pretty common as it contains a number of APIs such as NSObject (NSDate, NSString, and NSDateFormatter). 

You can import this into a script using the following line:

import Foundation


As with importing frameworks/modules/whatever (according to the language) – you can then consume the methods/variables/etc in your code (e.g.  let url = NSURL(fileURLWithPath: “names.plist”).

Super-Simple Bash Graphs

The sparkr gem is installed by default in macOS. To use it to produce simple graphs, simply run it followed by a series of integers:

sparkr 12 110 250 110 12

The result would be as follows:

This is useful for a quick and dirty visualization in scripts. For example, a series of 5, 10, 200 numbers that don’t have that much range where you’re just looking for a simple pattern. Like number of lines in logs, etc. Obviously, you can pay a lot of money for graphing frameworks and very fancy-schmancy tools. This is really just for me in small scripts. 

Note: sparkr isn’t installed on all Mac systems. to install it manually use:

sudo gem install sparkr

Thanks to Armin Briegel for pointing out that sparkr isn’t installed by default on the latest OSen.

Command Line Fu: Open Hidden Apps In macOS

macOS allows you to launch an app but in a hidden state. To do so, use the open command to open the app and then use the -a flag to specify the path of the app and –hide after the path to the app, as follows:

/usr/bin/open -a /Applications/Notes.app --hide

Quick and Dirty OpenBSM Auditing In macOS

OpenBSM is a subsystem that has been installed on the Mac for some time. OpenBSM provides that ability to create and read audit logs based on the Common Criteria standards.

Audit Logs

The quick and easy way to see what OpenBSM is auditing is to cat the /etc/security/audit_control file:

cat /etc/security/audit_control

The output displays the directory of audit logs, as well as what is currently being audited. By default the configuration is as follows:

#
# $P4: //depot/projects/trustedbsd/openbsm/etc/audit_control#8 $
#
dir:/var/audit
flags:lo,aa
minfree:5
naflags:lo,aa
policy:cnt,argv
filesz:2M
expire-after:10M
superuser-set-sflags-mask:has_authenticated,has_console_access
superuser-clear-sflags-mask:has_authenticated,has_console_access
member-set-sflags-mask:
member-clear-sflags-mask:has_authenticated

You can then see all of the files in your audit log, using a standard ls of those 

ls /var/audit

As you can see, the files are then stored with a date/time stamp naming convention. 

20180119012009.crash_recovery 20180407065646.20180407065716 20180407073931.20180407074018
20180119022233.crash_recovery 20180407065716.20180407065747 20180407074018.20180407074050
20180119043338.crash_recovery 20180407065747.20180407065822 20180407074050.20180511030725
20180119134354.crash_recovery 20180407065822.20180407065853 20180511030725.crash_recovery
20180208172535.crash_recovery 20180407065853.20180407065928 20180616025641.crash_recovery
20180219133137.crash_recovery 20180407065928.20180407070004 20180624022028.crash_recovery
20180312153634.crash_recovery 20180407070004.20180407070036 20180718235941.crash_recovery
20180312160131.crash_recovery 20180407070036.20180407071722 20180720031150.crash_recovery
20180322141701.crash_recovery 20180407071722.20180407072215 20180724021901.crash_recovery
20180330190040.crash_recovery 20180407072215.20180407072259 20180728173033.crash_recovery
20180330191420.20180407064622 20180407072259.20180407073747 20180907031058.crash_recovery
20180407064622.20180407065616 20180407073747.20180407073836 20180911021141.not_terminated
20180407065616.20180407065646 20180407073836.20180407073931 current

The files are binary and so cannot be read properly without the use of a tool to interpret the output. In the next section we will review how to read the logs. 

Using praudit

Binary files aren’t easy to read. Using the praudit binary, you can dump audit logs into XML using the -x flag followed by the path of the log. For example, the following command would read a given log in the above /var/audit example directory:

praudit -x 20180407065747.20180407065822

One record of the output would look as follows

<record version="11" event="session start" modifier="0" time="Sat Apr 7 01:58:22 2018" msec=" + 28 msec" >
<argument arg-num="1" value="0x0" desc="sflags" />
<argument arg-num="2" value="0x0" desc="am_success" />
<argument arg-num="3" value="0x0" desc="am_failure" />
<subject audit-uid="-1" uid="root" gid="wheel" ruid="root" rgid="wheel" pid="0" sid="100645" tid="0 0.0.0.0" />
<return errval="success" retval="0" />
</record>

In the above output, you’ll find the time that an event was logged, as well as the type of event. This could be parsed for specific events, and, as an example, just dump the time and event in a simple json or xml for tracking in another tool. For example, if you’re doing statistical analysis for how many times privileges were escalated as a means of detecting a bad actor on a system.

You can also use the auditreduce command to filter records. Once filtered, results are still in binary and must be converted using praudit.

Move From Hosting Files From A macOS Server To A macOS Client

Migrating file services from a macOS Server to a macOS Client can be a bit traumatic at first. Mostly because the thought itself can be a bit daunting. But once you get started, it’s pretty simple. Mostly because there’s less to do. And that can be a challenge. While there are ways to hack together solutions for network homes and other more advanced features, if you’re doing that, then you’re missing a key point here. 

Let’s start by documenting our existing share points. We’ll do this with the serveradmin command and using the settings verb for the sharing service as follows:

sudo serveradmin settings sharing

Each share is an item in the sharePointList array, with the following:

sharing:sharePointList:_array_id:/Users/charles.edge/Public:nfsExportRecord = _empty_array sharing:sharePointList:_array_id:/Users/charles.edge/Public:smbName = “Charles Edge’s Public Folder” sharing:sharePointList:_array_id:/Users/charles.edge/Public:name = “Charles Edge’s Public Folder” sharing:sharePointList:_array_id:/Users/charles.edge/Public:afpIsGuestAccessEnabled = yes sharing:sharePointList:_array_id:/Users/charles.edge/Public:isIndexingEnabled = no sharing:sharePointList:_array_id:/Users/charles.edge/Public:dsAttrTypeNative\:sharepoint_group_id = “6C37A421-C506-4523-8769-1AF6EA245B68” sharing:sharePointList:_array_id:/Users/charles.edge/Public:mountedOnPath = “/” sharing:sharePointList:_array_id:/Users/charles.edge/Public:dsAttrTypeNative\:sharepoint_account_uuid = “C0405AE4-6CBE-40C7-9584-174687C80C07” sharing:sharePointList:_array_id:/Users/charles.edge/Public:path = “/Users/charles.edge/Public” sharing:sharePointList:_array_id:/Users/charles.edge/Public:smbIsShared = yes sharing:sharePointList:_array_id:/Users/charles.edge/Public:smbIsGuestAccessEnabled = yes sharing:sharePointList:_array_id:/Users/charles.edge/Public:afpName = “Charles Edge’s Public Folder” sharing:sharePointList:_array_id:/Users/charles.edge/Public:dsAttrTypeStandard\:GeneratedUID = “5C13E2AA-A86D-45D0-80B4-00CA86DE2253” sharing:sharePointList:_array_id:/Users/charles.edge/Public:smbDirectoryMask = “755” sharing:sharePointList:_array_id:/Users/charles.edge/Public:afpIsShared = yes sharing:sharePointList:_array_id:/Users/charles.edge/Public:smbCreateMask = “644” sharing:sharePointList:_array_id:/Users/charles.edge/Public:ftpName = “Charles Edge’s Public Folder”

Once you’ve removed the Server app, you’ll be left with using the sharing command. Using that command, you can list shares using the -l option:

sharing -l

That same share then appears as follows:

List of Share Points
name: Charles Edge’s Public Folder
path: /Users/charles.edge/Public
afp: {
name: Charles Edge’s Public Folder
shared: 1
guest access: 1
inherit perms: 0
}
smb: {
name: Charles Edge’s Public Folder
shared: 1
guest access: 1
read-only: 0
sealed: 0
}


Or from the Sharing System Preference Pane.

Now you just have to loop through and create each share (although they should co-exist between tools). To create a share, click on the plus sign under Shared Folders.

You can then browse to the folder you’d like to share. Next, we’ll give access to the directory. Use the plus sign on the right side of the screen and then select the user or group you’d like to add to the list that has access to the directory (while the directory is highlighted in the list on the left).

Once the user is in the list, use the permissions on the right side of the user list to select what level each user or group gets.

You have additional controls for file and folder security that can be set at either the directory that is shared or those below it hierarchically. To do so, highlight the directory and use the Get Info option under the File menu in the Finder.

Note: You can also check the Shared Folder box on these folders to share them, meaning you have one less step once you get used to the workflow!

Backup Macs with Carbonite

Carbonite is a great tool for backing up Macs and Windows devices. To install Carbonite, download it from www.carbonite.com. Once downloaded, copy the app to the /Applications directory and open the app. 

The Carbonite app will then install the components required to support the backup operations and index the drive.

Next, you’ll see some basic folders that will be backed up. Check the box for those you want to add to the backup (or do this later) and click the Install button.
  
Click Open Carbonite.

Notice that the backup has begun! The only really customer-installable action is to select the directories to be backed up, which is done using the left-hand sidebar. 

And that’s it. There aren’t a lot of other options in the GUI. You can access more options at /Library/Preferences/com.carbonite.carbonite.plist.