Medium - Daemons and Agents - main.swift

IOServicesTestLaunchAgent.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>IOServicesTestLaunchAgent</string>
        <key>Disabled</key>
        <false/>
        <key>KeepAlive</key>
        <dict>
            <key>SuccessfulExit</key>
            <false/>
        </dict>
        <key>Program</key>
        <string>/Users/chris/Library/Developer/Xcode/DerivedData/IOServicesTest-fmrplonbcfeolhcpagogehzpkqzz/Build/Products/Debug/IOServicesTest</string>
        <key>RunAtLoad</key>
        <true/>
    </dict>
</plist>

IOServicesTestLaunchDaemon.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>IOServicesTestLaunchDaemon</string>
        <key>Disabled</key>
        <false/>
        <key>KeepAlive</key>
        <true />
        <key>Program</key>
        <string>/Users/chris/Library/Developer/Xcode/DerivedData/IOServicesTest-fmrplonbcfeolhcpagogehzpkqzz/Build/Products/Debug/IOServicesTest</string>
    </dict>
</plist>

main.swift

import Foundation
import IOKit.hid
import OSLog

func tryOpenHidDevice(options:Int) -> Bool{
    let deviceMatch = IOServiceMatching(kIOHIDDeviceKey)
    let match = IOServiceGetMatchingService(kIOMasterPortDefault, deviceMatch);
    let deviceRef = IOHIDDeviceCreate(kCFAllocatorDefault, match);
    let result = IOHIDDeviceOpen(deviceRef!, IOOptionBits(options));
    if(result == kIOReturnSuccess) {
        os_log("Device opened successfully")
        IOHIDDeviceClose(deviceRef!, IOOptionBits(kIOHIDOptionsTypeNone))
        return true;
    } else {
        os_log("Device opened failed")
        return false;
    }
}
    
if(getuid() == 0) {
    os_log("Running as daemon");
    // Open will fail if the agent hasn't prompted the
    // user to give access to input monitoring.
    if(tryOpenHidDevice(options: kIOHIDOptionsTypeSeizeDevice)) {
        os_log("Daemon now has access to seize HID devices");
        // You'd now let trigger the actual daemon code to run, now
        // that it has the HID access it needs.
    } else {
        os_log("Daemon still waiting for HID open access");
        // Not much we can do but try again soon.
        // Quit the agent, let launchd start it again soon.
        exit(1)
    }
} else {
    os_log("Running as agent");
    // We run this to trigger the TCC prompt
    if(tryOpenHidDevice(options: kIOHIDOptionsTypeNone)) {
        // Try again soon - you'd use a timer of some sort here.
    } else {
        // It worked. Let the agent exit, no longer needed.
        exit(0);
    }
}