Logging: Use ringlogger for logging from the extension

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

WireGuard/Shared/Logging/Logger.swift

@@ -0,0 +1,54 @@
+// SPDX-License-Identifier: MIT
+// Copyright © 2018 WireGuard LLC. All Rights Reserved.
+
+import os.log
+
+class Logger {
+    static var logPtr: UnsafeMutablePointer<log>?
+
+    static func configure(withFilePath filePath: String) -> Bool {
+        let logPtr = filePath.withCString { filePathCStr -> UnsafeMutablePointer<log>? in
+            return open_log(filePathCStr)
+        }
+        Logger.logPtr = logPtr
+        return (logPtr != nil)
+    }
+
+    static func writeLog(mergedWith otherLogFile: String, to targetFile: String) -> Bool {
+        let otherlogPtr = otherLogFile.withCString { otherLogFileCStr -> UnsafeMutablePointer<log>? in
+            return open_log(otherLogFileCStr)
+        }
+        if let thisLogPtr = Logger.logPtr, let otherlogPtr = otherlogPtr {
+            return targetFile.withCString { targetFileCStr -> Bool in
+                let returnValue = write_logs_to_file(targetFileCStr, thisLogPtr, otherlogPtr)
+                return (returnValue == 0)
+            }
+        }
+        return false
+    }
+}
+
+func wg_log(_ type: OSLogType, staticMessage msg: StaticString) {
+    // Write to os log
+    os_log(msg, log: OSLog.default, type: type)
+    // Write to file log
+    let msgString: String = msg.withUTF8Buffer { (ptr: UnsafeBufferPointer<UInt8>) -> String in
+        return String(decoding: ptr, as: UTF8.self)
+    }
+    file_log(type: type, message: msgString)
+}
+
+func wg_log(_ type: OSLogType, message msg: String) {
+    // Write to os log
+    os_log("%{public}s", log: OSLog.default, type: type, msg)
+    // Write to file log
+    file_log(type: type, message: msg)
+}
+
+private func file_log(type: OSLogType, message: String) {
+    message.withCString { messageCStr in
+        if let logPtr = Logger.logPtr {
+            write_msg_to_log(logPtr, messageCStr)
+        }
+    }
+}