Retry file pull without run-as when package is not an application

Summary: When an android package is not an application, the `run-as` command will fail. In this case, the package might be an operating system service package. In this case, it may be possible for the user to run adb as root. Note that Flipper does not restart adbd via `adb root` on behalf of the user; the command is simply retried without `run-as`.

Reviewed By: jknoxville

Differential Revision: D20920582

fbshipit-source-id: 8db86084c3c3a61d8322edb1e34fdfdf48d0412d

desktop/app/src/utils/androidContainerUtilityInternal.tsx

@@ -16,6 +16,7 @@ import {UnsupportedError} from './metrics';
 import adbkit, {Client} from 'adbkit';
 
 const allowedAppNameRegex = /^[a-zA-Z0-9._\-]+$/;
+const appNotApplicationRegex = /is not an application/;
 const appNotDebuggableRegex = /debuggable/;
 const operationNotPermittedRegex = /not permitted/;
 const logTag = 'androidContainerUtility';
@@ -48,6 +49,21 @@ export function validateFileContent(content: string): Promise<FileContent> {
   );
 }
 
+enum RunAsErrorCode {
+  NotAnApp = 1,
+  NotDebuggable = 2,
+}
+
+class RunAsError extends Error {
+  code: RunAsErrorCode;
+
+  constructor(code: RunAsErrorCode, message?: string) {
+    super(message);
+    this.code = code;
+    Object.setPrototypeOf(this, new.target.prototype);
+  }
+}
+
 export function _push(
   client: Client,
   deviceId: string,
@@ -70,7 +86,24 @@ export function _pull(
   app: AppName,
   path: FilePath,
 ): Promise<string> {
-  return executeCommandAsApp(client, deviceId, app, `cat '${path}'`);
+  return executeCommandAsApp(client, deviceId, app, `cat '${path}'`).catch(
+    (error) => {
+      if (
+        error instanceof RunAsError &&
+        error.code == RunAsErrorCode.NotAnApp
+      ) {
+        // Fall back to running the command directly. This will work if adb is running as root.
+        return client
+          .shell(deviceId, `echo "cat ${path}" | su`)
+          .then(adbkit.util.readAll)
+          .then((buffer) => buffer.toString())
+          .catch(() => {
+            throw error;
+          });
+      }
+      throw error;
+    },
+  );
 }
 
 // Keep this method private since it relies on pre-validated arguments
@@ -85,8 +118,15 @@ function executeCommandAsApp(
     .then(adbkit.util.readAll)
     .then((buffer) => buffer.toString())
     .then((output) => {
+      if (output.match(appNotApplicationRegex)) {
+        throw new RunAsError(
+          RunAsErrorCode.NotAnApp,
+          `Android package ${app} is not an application. To use it with Flipper, either run adb as root or add an <application> tag to AndroidManifest.xml`,
+        );
+      }
       if (output.match(appNotDebuggableRegex)) {
-        throw new Error(
+        throw new RunAsError(
+          RunAsErrorCode.NotDebuggable,
           `Android app ${app} is not debuggable. To use it with Flipper, add android:debuggable="true" to the application section of AndroidManifest.xml`,
         );
       }