NE: Communicate last error to app through a shared file

Signed-off-by: Roopesh Chander <roop@roopc.net>

1 files changed, 30 insertions, 5 deletions

diff --git a/WireGuard/WireGuardNetworkExtension/ErrorNotifier.swift b/WireGuard/WireGuardNetworkExtension/ErrorNotifier.swift
index 163535a..c392233 100644
--- a/WireGuard/WireGuardNetworkExtension/ErrorNotifier.swift
+++ b/WireGuard/WireGuardNetworkExtension/ErrorNotifier.swift
@@ -4,7 +4,17 @@
 import NetworkExtension
 
 class ErrorNotifier {
-    static func errorMessage(for error: PacketTunnelProviderError) -> (String, String)? {
+
+    let activationAttemptId: String?
+    weak var tunnelProvider: NEPacketTunnelProvider?
+
+    init(activationAttemptId: String?, tunnelProvider: NEPacketTunnelProvider) {
+        self.activationAttemptId = activationAttemptId
+        self.tunnelProvider = tunnelProvider
+        ErrorNotifier.removeLastErrorFile()
+    }
+
+    func errorMessage(for error: PacketTunnelProviderError) -> (String, String)? {
         switch error {
         case .savedProtocolConfigurationIsInvalid:
             return ("Activation failure", "Could not retrieve tunnel information from the saved configuration")
@@ -17,9 +27,24 @@ class ErrorNotifier {
         }
     }
 
-    static func notify(_ error: PacketTunnelProviderError, from tunnelProvider: NEPacketTunnelProvider) {
-        guard let (title, message) = ErrorNotifier.errorMessage(for: error) else { return }
-        // displayMessage() is deprecated, but there's no better alternative to show the error to the user
-        tunnelProvider.displayMessage("\(title): \(message)") { _ in }
+    func notify(_ error: PacketTunnelProviderError) {
+        guard let (title, message) = errorMessage(for: error) else { return }
+        if let activationAttemptId = activationAttemptId, let lastErrorFilePath = FileManager.networkExtensionLastErrorFileURL?.path {
+            // The tunnel was started from the app
+            let errorMessageData = "\(activationAttemptId)\n\(title)\n\(message)".data(using: .utf8)
+            FileManager.default.createFile(atPath: lastErrorFilePath, contents: errorMessageData, attributes: nil)
+        } else {
+            // The tunnel was probably started from iOS Settings app
+            if let tunnelProvider = self.tunnelProvider {
+                // displayMessage() is deprecated, but there's no better alternative if invoked from iOS Settings
+                tunnelProvider.displayMessage("\(title): \(message)") { _ in }
+            }
+        }
+    }
+
+    static func removeLastErrorFile() {
+        if let lastErrorFileURL = FileManager.networkExtensionLastErrorFileURL {
+            _ = FileManager.deleteFile(at: lastErrorFileURL)
+        }
     }
 }