Use SIGKILL to kill old processes

Fix #1455.

Note that in later Android versions, only processes under same uid will be listed and this will be quite efficient.

mobile/src/main/scala/com/github/shadowsocks/bg/Executable.scala

@@ -1,9 +1,14 @@
 package com.github.shadowsocks.bg
 
+import java.io.File
 import java.util.Locale
-import java.util.concurrent.TimeUnit
 
+import android.text.TextUtils
 import android.util.Log
+import com.github.shadowsocks.JniHelper
+import com.github.shadowsocks.ShadowsocksApplication.app
+
+import scala.io.Source
 
 /**
   * @author Mygod
@@ -16,12 +21,16 @@ object Executable {
   val TUN2SOCKS = "libtun2socks.so"
   val OVERTURE = "liboverture.so"
 
-  val EXECUTABLES = Array(SS_LOCAL, SS_TUNNEL, PDNSD, REDSOCKS, TUN2SOCKS, OVERTURE)
+  val EXECUTABLES = Set(SS_LOCAL, SS_TUNNEL, PDNSD, REDSOCKS, TUN2SOCKS, OVERTURE)
 
-  def killAll() {
-    val killer = new ProcessBuilder("killall" +: EXECUTABLES: _*).start()
-    if (!killer.waitFor(1, TimeUnit.SECONDS))
-      Log.w("killall", "%s didn't exit within 1s. Post-crash clean-up may have failed."
-        .formatLocal(Locale.ENGLISH, killer.toString))
-  }
+  def killAll(): Unit =
+    for (process <- new File("/proc").listFiles((_, name) => TextUtils.isDigitsOnly(name))) {
+      val exe = new File(Source.fromFile(new File(process, "cmdline")).mkString.split("\0", 2).head)
+      if (exe.getParent == app.getApplicationInfo.nativeLibraryDir && EXECUTABLES.contains(exe.getName))
+        JniHelper.sigkill(process.getName.toInt) match {
+          case 0 =>
+          case errno => Log.w("kill", "SIGKILL %s (%d) failed with %d"
+            .formatLocal(Locale.ENGLISH, exe.getAbsolutePath, process.getName, errno))
+        }
+    }
 }