Dump all the possible useful information

mobile/src/main/java/be/mygod/vpnhotspot/SettingsPreferenceFragment.kt

@@ -13,6 +13,7 @@ import be.mygod.vpnhotspot.net.Routing
 import com.takisoft.fix.support.v7.preference.PreferenceFragmentCompatDividers
 import java.io.File
 import java.io.IOException
+import java.io.PrintWriter
 
 class SettingsPreferenceFragment : PreferenceFragmentCompatDividers() {
     private val customTabsIntent by lazy {
@@ -31,19 +32,23 @@ class SettingsPreferenceFragment : PreferenceFragmentCompatDividers() {
             val logDir = File(activity.cacheDir, "log")
             logDir.mkdir()
             val logFile = File.createTempFile("vpnhotspot-", ".log", logDir)
-            logFile.printWriter().use { writer ->
+            logFile.outputStream().use { out ->
+                PrintWriter(out.bufferedWriter()).use { writer ->
                     writer.write("${BuildConfig.VERSION_CODE} is running on API ${Build.VERSION.SDK_INT}\n\n")
+                    writer.flush()
                     try {
-                    writer.write(Runtime.getRuntime().exec(arrayOf("logcat", "-d"))
+                        Runtime.getRuntime().exec(arrayOf("logcat", "-d")).inputStream.use { it.copyTo(out) }
-                            .inputStream.bufferedReader().readText())
                     } catch (e: IOException) {
                         e.printStackTrace(writer)
                     }
                     writer.write("\n")
+                    writer.flush()
                     try {
-                    writer.write(Routing.dump())
+                        Routing.dump()?.use { it.copyTo(out) }
                     } catch (e: IOException) {
                         e.printStackTrace(writer)
+                        writer.flush()
+                    }
                 }
             }
             startActivity(Intent.createChooser(Intent(Intent.ACTION_SEND)

mobile/src/main/java/be/mygod/vpnhotspot/Utils.kt

@@ -8,7 +8,9 @@ import android.databinding.BindingAdapter
 import android.support.annotation.DrawableRes
 import android.util.Log
 import android.widget.ImageView
+import be.mygod.vpnhotspot.App.Companion.app
 import java.io.IOException
+import java.io.InputStream
 import java.net.NetworkInterface
 
 fun debugLog(tag: String?, message: String?) {
@@ -37,23 +39,27 @@ fun NetworkInterface.formatAddresses() =
 
 private const val NOISYSU_TAG = "NoisySU"
 private const val NOISYSU_SUFFIX = "SUCCESS\n"
-fun loggerSu(command: String): String? {
+fun loggerSuStream(command: String): InputStream? {
     val process = try {
         ProcessBuilder("su", "-c", command)
                 .redirectErrorStream(true)
+                .directory(app.cacheDir)
                 .start()
     } catch (e: IOException) {
         return null
     }
-    process.waitFor()
     try {
         val err = process.errorStream.bufferedReader().readText()
         if (err.isNotBlank()) Log.e(NOISYSU_TAG, err)
     } catch (e: IOException) {
         e.printStackTrace()
     }
+    return process.inputStream
+}
+fun loggerSu(command: String): String? {
+    val stream = loggerSuStream(command) ?: return null
     return try {
-        process.inputStream.bufferedReader().readText()
+        stream.bufferedReader().readText()
     } catch (e: IOException) {
         e.printStackTrace()
         null

mobile/src/main/java/be/mygod/vpnhotspot/net/Routing.kt

@@ -4,9 +4,10 @@ import android.os.Build
 import be.mygod.vpnhotspot.App.Companion.app
 import be.mygod.vpnhotspot.R
 import be.mygod.vpnhotspot.debugLog
-import be.mygod.vpnhotspot.loggerSu
+import be.mygod.vpnhotspot.loggerSuStream
 import be.mygod.vpnhotspot.noisySu
 import java.io.IOException
+import java.io.InputStream
 import java.net.Inet4Address
 import java.net.InetAddress
 import java.net.NetworkInterface
@@ -30,19 +31,28 @@ class Routing(val upstream: String?, val downstream: String, ownerAddress: InetA
                 "$IPTABLES -X vpnhotspot_fwd",
                 "quiet while ip rule del priority 17900; do done")
 
-        fun dump() = loggerSu("""
+        fun dump(): InputStream? {
+            val commands = StringBuilder()
+            // https://android.googlesource.com/platform/external/iptables/+/android-7.0.0_r1/iptables/Android.mk#34
+            val iptablesSave = if (Build.VERSION.SDK_INT >= 24) "iptables-save" else {
+                commands.appendln("ln -sf /system/bin/iptables ./iptables-save")
+                "./iptables-save"
+            }
+            commands.append("""
                 |echo logcat-su
                 |logcat -d
                 |echo
                 |echo iptables
-            |sh -c 'exec -a iptables-save iptables'
+                |$iptablesSave
                 |echo
                 |echo iptables -t nat
-            |sh -c 'exec -a iptables-save iptables -t nat'
+                |$iptablesSave -t nat
                 |echo
                 |echo ip rule
                 |ip rule
             """.trimMargin())
+            return loggerSuStream(commands.toString())
+        }
     }
 
     class InterfaceNotFoundException : IOException() {