Migrate tunnel related classes to tunnel/ Gradle module

Signed-off-by: Harsh Shandilya <me@msfjarvis.dev>

1 files changed, 211 insertions, 0 deletions

diff --git a/tunnel/src/main/java/com/wireguard/android/util/RootShell.java b/tunnel/src/main/java/com/wireguard/android/util/RootShell.java
new file mode 100644
index 00000000..1fc2c9f2
--- /dev/null
+++ b/tunnel/src/main/java/com/wireguard/android/util/RootShell.java
@@ -0,0 +1,211 @@
+/*
+ * Copyright © 2017-2019 WireGuard LLC. All Rights Reserved.
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package com.wireguard.android.util;
+
+import android.content.Context;
+import androidx.annotation.Nullable;
+import android.util.Log;
+
+import com.wireguard.android.util.RootShell.RootShellException.Reason;
+
+import java.io.BufferedReader;
+import java.io.File;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.io.OutputStreamWriter;
+import java.nio.charset.StandardCharsets;
+import java.util.Collection;
+import java.util.UUID;
+
+/**
+ * Helper class for running commands as root.
+ */
+
+public class RootShell {
+    private static final String SU = "su";
+    private static final String TAG = "WireGuard/" + RootShell.class.getSimpleName();
+
+    private final File localBinaryDir;
+    private final File localTemporaryDir;
+    private final Object lock = new Object();
+    private final String preamble;
+    @Nullable private Process process;
+    @Nullable private BufferedReader stderr;
+    @Nullable private OutputStreamWriter stdin;
+    @Nullable private BufferedReader stdout;
+
+    public RootShell(final Context context) {
+        localBinaryDir = new File(context.getCodeCacheDir(), "bin");
+        localTemporaryDir = new File(context.getCacheDir(), "tmp");
+        preamble = String.format("export CALLING_PACKAGE=%s PATH=\"%s:$PATH\" TMPDIR='%s'; id -u\n",
+                context.getPackageName(), localBinaryDir, localTemporaryDir);
+    }
+
+    private static boolean isExecutableInPath(final String name) {
+        final String path = System.getenv("PATH");
+        if (path == null)
+            return false;
+        for (final String dir : path.split(":"))
+            if (new File(dir, name).canExecute())
+                return true;
+        return false;
+    }
+
+    private boolean isRunning() {
+        synchronized (lock) {
+            try {
+                // Throws an exception if the process hasn't finished yet.
+                if (process != null)
+                    process.exitValue();
+                return false;
+            } catch (final IllegalThreadStateException ignored) {
+                // The existing process is still running.
+                return true;
+            }
+        }
+    }
+
+    /**
+     * Run a command in a root shell.
+     *
+     * @param output  Lines read from stdout are appended to this list. Pass null if the
+     *                output from the shell is not important.
+     * @param command Command to run as root.
+     * @return The exit value of the command.
+     */
+    public int run(@Nullable final Collection<String> output, final String command)
+            throws IOException, RootShellException {
+        synchronized (lock) {
+            /* Start inside synchronized block to prevent a concurrent call to stop(). */
+            start();
+            final String marker = UUID.randomUUID().toString();
+            final String script = "echo " + marker + "; echo " + marker + " >&2; (" + command +
+                    "); ret=$?; echo " + marker + " $ret; echo " + marker + " $ret >&2\n";
+            Log.v(TAG, "executing: " + command);
+            stdin.write(script);
+            stdin.flush();
+            String line;
+            int errnoStdout = Integer.MIN_VALUE;
+            int errnoStderr = Integer.MAX_VALUE;
+            int markersSeen = 0;
+            while ((line = stdout.readLine()) != null) {
+                if (line.startsWith(marker)) {
+                    ++markersSeen;
+                    if (line.length() > marker.length() + 1) {
+                        errnoStdout = Integer.valueOf(line.substring(marker.length() + 1));
+                        break;
+                    }
+                } else if (markersSeen > 0) {
+                    if (output != null)
+                        output.add(line);
+                    Log.v(TAG, "stdout: " + line);
+                }
+            }
+            while ((line = stderr.readLine()) != null) {
+                if (line.startsWith(marker)) {
+                    ++markersSeen;
+                    if (line.length() > marker.length() + 1) {
+                        errnoStderr = Integer.valueOf(line.substring(marker.length() + 1));
+                        break;
+                    }
+                } else if (markersSeen > 2) {
+                    Log.v(TAG, "stderr: " + line);
+                }
+            }
+            if (markersSeen != 4)
+                throw new RootShellException(Reason.SHELL_MARKER_COUNT_ERROR, markersSeen);
+            if (errnoStdout != errnoStderr)
+                throw new RootShellException(Reason.SHELL_EXIT_STATUS_READ_ERROR);
+            Log.v(TAG, "exit: " + errnoStdout);
+            return errnoStdout;
+        }
+    }
+
+    public void start() throws IOException, RootShellException {
+        if (!isExecutableInPath(SU))
+            throw new RootShellException(Reason.NO_ROOT_ACCESS);
+        synchronized (lock) {
+            if (isRunning())
+                return;
+            if (!localBinaryDir.isDirectory() && !localBinaryDir.mkdirs())
+                throw new RootShellException(Reason.CREATE_BIN_DIR_ERROR);
+            if (!localTemporaryDir.isDirectory() && !localTemporaryDir.mkdirs())
+                throw new RootShellException(Reason.CREATE_TEMP_DIR_ERROR);
+            try {
+                final ProcessBuilder builder = new ProcessBuilder().command(SU);
+                builder.environment().put("LC_ALL", "C");
+                try {
+                    process = builder.start();
+                } catch (final IOException e) {
+                    // A failure at this stage means the device isn't rooted.
+                    final RootShellException rse = new RootShellException(Reason.NO_ROOT_ACCESS);
+                    rse.initCause(e);
+                    throw rse;
+                }
+                stdin = new OutputStreamWriter(process.getOutputStream(), StandardCharsets.UTF_8);
+                stdout = new BufferedReader(new InputStreamReader(process.getInputStream(),
+                        StandardCharsets.UTF_8));
+                stderr = new BufferedReader(new InputStreamReader(process.getErrorStream(),
+                        StandardCharsets.UTF_8));
+                stdin.write(preamble);
+                stdin.flush();
+                // Check that the shell started successfully.
+                final String uid = stdout.readLine();
+                if (!"0".equals(uid)) {
+                    Log.w(TAG, "Root check did not return correct UID: " + uid);
+                    throw new RootShellException(Reason.NO_ROOT_ACCESS);
+                }
+                if (!isRunning()) {
+                    String line;
+                    while ((line = stderr.readLine()) != null) {
+                        Log.w(TAG, "Root check returned an error: " + line);
+                        if (line.contains("Permission denied"))
+                            throw new RootShellException(Reason.NO_ROOT_ACCESS);
+                    }
+                    throw new RootShellException(Reason.SHELL_START_ERROR, process.exitValue());
+                }
+            } catch (final IOException | RootShellException e) {
+                stop();
+                throw e;
+            }
+        }
+    }
+
+    public void stop() {
+        synchronized (lock) {
+            if (process != null) {
+                process.destroy();
+                process = null;
+            }
+        }
+    }
+
+    public static class RootShellException extends Exception {
+        public enum Reason {
+            NO_ROOT_ACCESS,
+            SHELL_MARKER_COUNT_ERROR,
+            SHELL_EXIT_STATUS_READ_ERROR,
+            SHELL_START_ERROR,
+            CREATE_BIN_DIR_ERROR,
+            CREATE_TEMP_DIR_ERROR
+        }
+        private final Reason reason;
+        private final Object[] format;
+        public RootShellException(final Reason reason, final Object ...format) {
+            this.reason = reason;
+            this.format = format;
+        }
+        public boolean isIORelated() {
+            return reason != Reason.NO_ROOT_ACCESS;
+        }
+        public Reason getReason() {
+            return reason;
+        }
+        public Object[] getFormat() {
+            return format;
+        }
+    }
+}