Fix granting permission not working reliably with su

Author: darshanparajuli

app/src/main/java/com/dp/logcatapp/fragments/logcatlive/LogcatLiveFragment.kt

@@ -39,6 +39,11 @@ import com.google.android.material.floatingactionbutton.FloatingActionButton
 import com.google.android.material.snackbar.Snackbar
 import kotlinx.coroutines.*
 import kotlinx.coroutines.Dispatchers.Default
+import java.io.BufferedReader
+import java.io.BufferedWriter
+import java.io.InputStreamReader
+import java.io.OutputStreamWriter
+import java.util.*
 
 class LogcatLiveFragment : BaseFragment(), ServiceConnection, LogsReceivedListener {
     companion object {
@@ -678,17 +683,11 @@ class LogcatLiveFragment : BaseFragment(), ServiceConnection, LogsReceivedListen
             dialog.show(fragmentManager, AskingForRootAccessDialogFragment.TAG)
 
             val result = withContext(Dispatchers.IO) {
-                val cmd = "pm grant ${BuildConfig.APPLICATION_ID} ${Manifest.permission.READ_LOGS}"
-                try {
-                    val process = Runtime.getRuntime().exec(arrayOf("su", "-c", cmd))
-                    process.waitFor()
-                } catch (e: Exception) {
-                    -1
-                }
+                grantPermissionWithSu()
             }
 
             dialog.dismissAllowingStateLoss()
-            if (result == 0) {
+            if (result) {
                 RestartAppMessageDialogFragment.newInstance().show(fragmentManager,
                         RestartAppMessageDialogFragment.TAG)
             } else {
@@ -699,6 +698,69 @@ class LogcatLiveFragment : BaseFragment(), ServiceConnection, LogsReceivedListen
         }
     }
 
+    private fun BufferedWriter.writeCmd(cmd: String) {
+        write(cmd)
+        newLine()
+        flush()
+    }
+
+    private suspend fun grantPermissionWithSu() = coroutineScope {
+        try {
+            val processBuilder = ProcessBuilder("su")
+            val process = processBuilder.start()
+
+            val stdoutWriter = BufferedWriter(OutputStreamWriter(process.outputStream))
+            val stdinReader = BufferedReader(InputStreamReader(process.inputStream))
+            val stderrReader = BufferedReader(InputStreamReader(process.errorStream))
+
+            val marker = "RESULT>>>${UUID.randomUUID()}>>>"
+            val stdoutResult = async {
+                var result = false
+
+                try {
+                    while (true) {
+                        val line = stdinReader.readLine()?.trim() ?: break
+
+                        val index = line.indexOf(marker)
+                        if (index != -1) {
+                            result = line.substring(index + marker.length) == "0"
+                            break
+                        }
+                    }
+                } catch (e: Exception) {
+                }
+
+                result
+            }
+
+            val stderrReaderResult = async {
+                try {
+                    while (true) {
+                        stderrReader.readLine()?.trim() ?: break
+                    }
+                } catch (e: Exception) {
+                }
+            }
+
+            val cmd = "pm grant ${BuildConfig.APPLICATION_ID} ${Manifest.permission.READ_LOGS}"
+            stdoutWriter.writeCmd(cmd)
+            stdoutWriter.writeCmd("echo \"$marker$?\"")
+
+            val finalResult = stdoutResult.await()
+
+            stdoutWriter.writeCmd("exit")
+
+            process.waitFor()
+            process.destroy()
+
+            stderrReaderResult.await()
+
+            finalResult
+        } catch (e: Exception) {
+            false
+        }
+    }
+
     private class LogFilter(filterInfo: FilterInfo) : Filter {
         val type = filterInfo.type
         val content = filterInfo.content