Root shell with no outputs

app/src/main/java/com/topjohnwu/magisk/utils/Shell.java

@@ -18,12 +18,12 @@ public class Shell {
     // -1 = problematic/unknown issue; 0 = not rooted; 1 = properly rooted
     public static int rootStatus;
 
-    private static boolean isInit = false;
-
     private final Process rootShell;
     private final DataOutputStream rootSTDIN;
     private final DataInputStream rootSTDOUT;
 
+    private boolean isValid;
+
     private Shell() {
         Process process;
         try {
@@ -34,15 +34,17 @@ public class Shell {
             rootShell = null;
             rootSTDIN = null;
             rootSTDOUT = null;
+            isValid = false;
             return;
         }
 
         rootStatus = 1;
+        isValid = true;
         rootShell = process;
         rootSTDIN = new DataOutputStream(rootShell.getOutputStream());
         rootSTDOUT = new DataInputStream(rootShell.getInputStream());
 
-        su("umask 022");
+        su_raw("umask 022");
         List<String> ret = su("echo -BOC-", "id");
 
         if (ret.isEmpty()) {
@@ -118,33 +120,43 @@ public class Shell {
     }
 
     public List<String> su(String... commands) {
+        if (!isValid) return null;
         List<String> res = new ArrayList<>();
         su(res, commands);
         return res;
     }
 
-    public void su(List<String> res, String... commands) {
-        try {
-            rootShell.exitValue();
-            return;  // The process is dead, return
-        } catch (IllegalThreadStateException ignored) {
-            // This should be the expected result
-        }
+    public void su_raw(String... commands) {
+        if (!isValid) return;
         synchronized (rootShell) {
-            StreamGobbler STDOUT = new StreamGobbler(rootSTDOUT, Collections.synchronizedList(res), true);
-            STDOUT.start();
             try {
                 for (String command : commands) {
                     rootSTDIN.write((command + "\n").getBytes("UTF-8"));
                     rootSTDIN.flush();
                 }
-                rootSTDIN.write(("echo \'-root-done-\'\n").getBytes("UTF-8"));
-                rootSTDIN.flush();
-                STDOUT.join();
-            } catch (InterruptedException | IOException e) {
+            } catch (IOException e) {
                 e.printStackTrace();
                 rootShell.destroy();
+                isValid = false;
             }
         }
     }
+
+    public void su(List<String> output, String... commands) {
+        if (!isValid) return;
+        try {
+            rootShell.exitValue();
+            isValid = false;
+            return;  // The process is dead, return
+        } catch (IllegalThreadStateException ignored) {
+            // This should be the expected result
+        }
+        synchronized (rootShell) {
+            StreamGobbler STDOUT = new StreamGobbler(rootSTDOUT, output, true);
+            STDOUT.start();
+            su_raw(commands);
+            su_raw("echo \'-root-done-\'");
+            try { STDOUT.join(); } catch (InterruptedException ignored) {}
+        }
+    }
 }

app/src/main/java/com/topjohnwu/magisk/utils/StreamGobbler.java

@@ -29,13 +29,17 @@ public class StreamGobbler extends Thread {
      * @param outputList  {@literal List<String>} to write to, or null
      */
     public StreamGobbler(InputStream inputStream, List<String> outputList) {
+        try {
+            while (inputStream.available() != 0) {
+                inputStream.skip(inputStream.available());
+            }
+        } catch (IOException ignored) {}
         reader = new BufferedReader(new InputStreamReader(inputStream));
         writer = outputList;
     }
 
     public StreamGobbler(InputStream inputStream, List<String> outputList, boolean root) {
-        reader = new BufferedReader(new InputStreamReader(inputStream));
-        writer = outputList;
+        this(inputStream, outputList);
         isRoot = root;
     }
 
@@ -48,7 +52,7 @@ public class StreamGobbler extends Thread {
                 if (TextUtils.equals(line, "-root-done-"))
                     return;
                 writer.add(line);
-                Logger.shell(isRoot, "OUT: " + line);
+                Logger.shell(isRoot, line);
             }
         } catch (IOException e) {
             // reader probably closed, expected exit condition

app/src/main/java/com/topjohnwu/magisk/utils/Utils.java

@@ -52,12 +52,12 @@ public class Utils {
     public static void createFile(Shell shell, String path) {
         String folder = path.substring(0, path.lastIndexOf('/'));
         String command = "mkdir -p " + folder + " 2>/dev/null; touch " + path + " 2>/dev/null; if [ -f \"" + path + "\" ]; then echo true; else echo false; fi";
-        shell.su(command);
+        shell.su_raw(command);
     }
 
     public static void removeItem(Shell shell, String path) {
         String command = "rm -rf " + path + " 2>/dev/null; if [ -e " + path + " ]; then echo false; else echo true; fi";
-        shell.su(command);
+        shell.su_raw(command);
     }
 
     public static List<String> getModList(Shell shell, String path) {
@@ -66,14 +66,8 @@ public class Utils {
     }
 
     public static List<String> readFile(Shell shell, String path) {
-        List<String> ret;
         String command = "cat " + path;
-        if (Shell.rootAccess()) {
-            ret = shell.su(command);
-        } else {
-            ret = Shell.sh(command);
-        }
-        return ret;
+        return shell.su(command);
     }
 
     public static void dlAndReceive(Context context, DownloadReceiver receiver, String link, String filename) {