Add 600ms timeout for waitpid

mobile/src/main/java/com/github/shadowsocks/JniHelper.java

@@ -54,7 +54,14 @@ public class JniHelper {
                 ? new ErrnoException("kill", errno) : new Exception("kill failed: " + errno);
     }
 
+    @Deprecated // Use Process.destroy() since API 24
+    public static int waitpidCompat(Process process) throws Exception {
+        if (Build.VERSION.SDK_INT >= 24) throw new UnsupportedOperationException("Never call this method in OpenJDK!");
+        return waitpid(process);
+    }
+
     private static native int sigterm(Process process);
+    private static native int waitpid(Process process);
     public static native int sendFd(int fd, String path);
     public static native void close(int fd);
 }

mobile/src/main/jni/jni-helper.cpp

@@ -14,6 +14,7 @@
 #include <sys/stat.h>
 #include <sys/types.h>
 #include <sys/socket.h>
+#include <sys/wait.h>
 #include <ancillary.h>
 
 #define LOGI(...) do { __android_log_print(ANDROID_LOG_INFO, LOG_TAG, __VA_ARGS__); } while(0)
@@ -41,6 +42,17 @@ jint Java_com_github_shadowsocks_jnihelper_sigterm(JNIEnv *env, jobject thiz, jo
     return kill(pid, SIGTERM) == -1 && errno != ESRCH ? errno : 0;
 }
 
+jint Java_com_github_shadowsocks_jnihelper_waitpid(JNIEnv *env, jobject thiz, jobject process) {
+    if (!env->IsInstanceOf(process, ProcessImpl)) {
+        THROW(env, "java/lang/ClassCastException",
+                   "Unsupported process object. Only java.lang.ProcessManager$ProcessImpl is accepted.");
+        return -1;
+    }
+    jint pid = env->GetIntField(process, ProcessImpl_pid);
+    int status;
+    return waitpid(pid, &status, WNOHANG);
+}
+
 void Java_com_github_shadowsocks_jnihelper_close(JNIEnv *env, jobject thiz, jint fd) {
     close(fd);
 }
@@ -84,11 +96,11 @@ static JNINativeMethod method_table[] = {
     { "sendFd", "(ILjava/lang/String;)I",
         (void*) Java_com_github_shadowsocks_jnihelper_sendfd },
     { "sigterm", "(Ljava/lang/Process;)I",
-        (void*) Java_com_github_shadowsocks_jnihelper_sigterm }
+        (void*) Java_com_github_shadowsocks_jnihelper_sigterm },
+    { "waitpid", "(Ljava/lang/Process;)I",
+        (void*) Java_com_github_shadowsocks_jnihelper_waitpid }
 };
 
-
-
 /*
  * Register several native methods for one class.
  */

mobile/src/main/scala/com/github/shadowsocks/GuardedProcess.scala

@@ -115,7 +115,12 @@ class GuardedProcess(cmd: String*) {
   private def destroyProcess() {
     if (Build.VERSION.SDK_INT < 24) {
       JniHelper.sigtermCompat(process)
-      process.waitFor()
+      var tries = 0
+      while (JniHelper.waitpidCompat(process) == 0 && tries < 3) {
+        Log.w(TAG, "still waiting for process " + Commandline.toString(cmd))
+        Thread.sleep(200)
+        tries += 1
+      }
     }
     process.destroy()
   }