android: use PackageManager to determine install AppSourceChecker (#517)

We were using MaybeGoogle to determine whether the app was installed from the Play Store, but this has not worked since the refactor.
Fixes tailscale/tailscale#13442
Updates tailscale/corp#23283

Signed-off-by: kari-ts <kari@tailscale.com>

android/src/main/java/com/tailscale/ipn/App.kt

@@ -77,7 +77,7 @@ class App : UninitializedApp(), libtailscale.AppContext, ViewModelStoreOwner {
 
   override fun getPlatformDNSConfig(): String = dns.dnsConfigAsString
 
-  override fun isPlayVersion(): Boolean = MaybeGoogle.isGoogle()
+  override fun getInstallSource(): String = AppSourceChecker.getInstallSource(this)
 
   override fun shouldUseGoogleDNSFallback(): Boolean = BuildConfig.USE_GOOGLE_DNS_FALLBACK
 

android/src/main/java/com/tailscale/ipn/AppSourceChecker.kt

@@ -0,0 +1,34 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+package com.tailscale.ipn
+
+import android.content.Context
+import android.os.Build
+import android.util.Log
+
+object AppSourceChecker {
+
+  const val TAG = "AppSourceChecker"
+
+  fun getInstallSource(context: Context): String {
+    val packageManager = context.packageManager
+    val packageName = context.packageName
+    Log.d(TAG, "Package name: $packageName")
+
+    val installerPackageName = if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.R) {
+        packageManager.getInstallSourceInfo(packageName).installingPackageName
+    } else {
+        packageManager.getInstallerPackageName(packageName)
+    }
+
+    Log.d(TAG, "Installer package name: $installerPackageName")
+
+    return when (installerPackageName) {
+        "com.android.vending" -> "googleplay"
+        "org.fdroid.fdroid" -> "fdroid"
+        "com.amazon.venezia" -> "amazon"
+        null -> "unknown"
+        else -> "unknown($installerPackageName)"
+    }
+}
+}

android/src/main/java/com/tailscale/ipn/MaybeGoogle.java

@@ -1,35 +0,0 @@
-// Copyright (c) Tailscale Inc & AUTHORS
-// SPDX-License-Identifier: BSD-3-Clause
-
-package com.tailscale.ipn;
-
-import android.app.Activity;
-
-import java.lang.reflect.Method;
-
-public class MaybeGoogle {
-    static boolean isGoogle() {
-        return getGoogle() != null;
-    }
-
-    static String getIdTokenForActivity(Activity act) {
-        Class<?> google = getGoogle();
-        if (google == null) {
-            return "";
-        }
-        try {
-            Method method = google.getMethod("getIdTokenForActivity", Activity.class);
-            return (String) method.invoke(null, act);
-        } catch (Exception e) {
-            return "";
-        }
-    }
-
-    private static Class getGoogle() {
-        try {
-            return Class.forName("com.tailscale.ipn.Google");
-        } catch (ClassNotFoundException e) {
-            return null;
-        }
-    }
-}

libtailscale/backend.go

@@ -105,9 +105,7 @@ type settingsFunc func(*router.Config, *dns.OSConfig) error
 func (a *App) runBackend(ctx context.Context) error {
 	paths.AppSharedDir.Store(a.dataDir)
 	hostinfo.SetOSVersion(a.osVersion())
-	if !a.appCtx.IsPlayVersion() {
-		hostinfo.SetPackage("nogoogle")
-	}
+	hostinfo.SetPackage(a.appCtx.GetInstallSource())
 	deviceModel := a.modelName()
 	if a.isChromeOS() {
 		deviceModel = "ChromeOS: " + deviceModel

libtailscale/interfaces.go

@@ -33,9 +33,8 @@ type AppContext interface {
 	// GetModelName gets the Android device's model name.
 	GetModelName() (string, error)
 
-	// IsPlayVersion reports whether this is the Google Play version of the app
-	// (as opposed to F-droid/sideloaded).
-	IsPlayVersion() bool
+	// GetInstallSource gets information about how the app was installed or updated.
+	GetInstallSource() string
 
 	// ShouldUseGoogleDNSFallback reports whether or not to use Google for DNS fallback.
 	ShouldUseGoogleDNSFallback() bool