Swift - Keychain Services SecKeychainSetDefault fails as root - Will not set default - swift

Question

I want to store something in the system keychain, but am seeing some weird behavior. In my app's scheme, I have Debug Process As set to root. However, when I check the default keychain via SecKeychainCopyDefault, it returns the login keychain for my current user.
As far as I know, the only way to write a keychain item to a specific keychain is to first set it as the default keychain using SecKeychainSetDefault and then perform the write. Obviously, since the default is set to my login chain in my debug environment, I'd need to set the default to the system keychain before attempting to write. I am doing the following to accomplish this:
// Store original default so we can restore it after we are done
var defaultKeychain: SecKeychain? = nil
SecKeychainCopyDefault(&defaultKeychain)
// Open System keychain
let cs = ("/Library/Keychains/System.keychain" as NSString).utf8String
var buffer = UnsafeMutablePointer<Int8>(mutating: cs)!
var systemKeychain: SecKeychain? = nil
SecKeychainOpen(buffer, &systemKeychain)
// Set System keychain to default
var status = SecKeychainSetDefault(systemKeychain)
NSLog(SecCopyErrorMessageString(status, nil) as String? ?? "")
// Ensure default keychain gets reset at end of scope
defer {
SecKeychainSetDefault(defaultKeychain)
}
// Add item to keychain below
...
However, I get the following output:
Will not set default: UID=0 does not own directory /Users/myuser
2019-12-11 09:54:31.262285-0700 App[99920:12060617] Write permissions error.
It seems as though even though my app is running as root, I don't have write access to the login keychain for some reason. The strange thing is, when I deploy my app as a background launch daemon, the default keychain is already the System keychain, not the login keychain, and things work properly. Obviously though I would like this behavior in my development environment as well.
How can I get around this issue? I need my keychain item to be in the System keychain, but even running the app as root doesn't seem to help when running in a debug environment.

Answer 1

The following workaround worked for me (on Mac OS 10.15) :
In your app's scheme set the "HOME" environment variable to a folder owned by root (e.g. '/' or '/var/root')