launchd that runs a console app from authenticator

Question

Created Dec ’22

Replies 7

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I have an authentication app (authApp) that runs on Mac. AuthApp lets you log in to the Mac. It runs in place of the default login screen. I have added a new button in authApp and I want that button to launch another app (let's call it newApp) when clicked. AuthApp is written in Objective-C and newApp in Swift. I am able to launch newApp from the login screen every time at logout with the help of launchd agents. But that is not what I want; I want it to open only when the button in AuthApp is clicked. This is my launchd plist

 `<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
        <key>Label</key>
        <string>com.example.apple-sample</string>
        <key>LimitLoadToSessionType</key>
        <string>LoginWindow</string>
        <key>KeepAlive</key>
        <true/>
        <key>ProgramArguments</key>
        <array>
        <string>/Library/PrivilegedHelperTools/newApp.app/Contents/MacOS/newApp</string>
        </array>
</dict>
</plist>`

The file is saved in /Library/LaunchAgents. newApp is in /Library/PrivilegedHelperTools. Is there a way to execute this launchd programmatically (Objective-C++/Swift) from the code so that newApp is launched? Please note this needs to be done before the user has logged in to the machine.

Answer 1

RituVarkey OP

Dec ’22

thanks in advance

Answer 2

DTS Engineer OP

Apple

Dec ’22

It runs in place of the default login screen.

By what mechanism? As an authorisation plug-in that presents an SFAuthorizationPluginView subclass?

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Quinn “The Eskimo!” @ Developer Technical Support @ Apple
let myEmail = "eskimo" + "1" + "@" + "apple.com"

Answer 3

RituVarkey OP

Dec ’22

Yes as an Authorisation plugin

Answer 4

DTS Engineer OP

Apple

Dec ’22

Authorisation plug-ins run in the pre-login environment which is quite strange. Running GUI apps directly from your plug-in is not supported [1]. You can use a pre-login agent but that presents two challenges:

IPC — The pre-login agent runs as a different user than the authorisation plug-in (root vs _securityagent).
General interface issues — It’s hard to coordinate the window in which your SFAuthorizationPluginView is hosted with any window being shown by the pre-login agent.

My recommendation here is that you open a DTS tech support incident so that I can help you one-on-one. Please reference this DevForums thread for context.

Share and Enjoy
—
Quinn “The Eskimo!” @ Developer Technical Support @ Apple
let myEmail = "eskimo" + "1" + "@" + "apple.com"

[1] I also see folks trying to run a web view from their authorisation plug-in, and that’s something we support either.

Answer 5

RituVarkey OP

Dec ’22

Thanks @eskimo for the reply. Thanks for confirming that pre-login agents is the way to go. Right now the GUI app is showing up all the time at logout. How can I get it to work when only the button on the authorisation plugin is clicked? I tried WatchPaths and QueueDirectories, when the button is clicked I created a file in the WatchPath directory so the launchd launches the app only when there is a file in the directory(according to the definition of WatchPaths/QueuDirectories). But that did not help. The GUI app is showing up irrespective of the file being there or not in the WatchPath folder.

Answer 6

RituVarkey OP

Jan ’23

Hi,

I was able to get it working by using "WatchPaths". For watchPaths to work the file need to be existing already. When the button was clicked I wrote to a file and my App would be launched because the file was modified. But my app stands behind the authorisation plugin window. It comes in front once clicked. I am able to toggle between windows. But it would be nice if I could have my app displayed in front. Can this be done ?

Also the app is launched only when logged out. Is it possible to display the app even when locked and not only logged out?

Answer 7

RituVarkey OP

Jan ’23

My launchd plist now: