feature/android 797c30b7abc: Initialize signal mask earlier

[Po Lu]

branch: feature/android
commit 797c30b7abc165d5ebe65474c7398ccad0e3023c
Author: Po Lu <luangruo@yahoo.com>
Commit: Po Lu <luangruo@yahoo.com>

    Initialize signal mask earlier
    
    * java/org/gnu/emacs/EmacsService.java (onCreate, run): Don't
    initialize signal mask here.
    * java/org/gnu/emacs/EmacsApplication.java (onCreate): Do it
    here instead.
    * src/android.c (JNICALL): Restore previous signal masks.
---
 java/org/gnu/emacs/EmacsApplication.java |  8 ++++++++
 java/org/gnu/emacs/EmacsService.java     | 25 -------------------------
 src/android.c                            | 23 ++++++++++++++++++++++-
 3 files changed, 30 insertions(+), 26 deletions(-)

diff --git a/java/org/gnu/emacs/EmacsApplication.java 
b/java/org/gnu/emacs/EmacsApplication.java
index d8b77acdf9e..8afa5bcedb4 100644
--- a/java/org/gnu/emacs/EmacsApplication.java
+++ b/java/org/gnu/emacs/EmacsApplication.java
@@ -78,7 +78,15 @@ public final class EmacsApplication extends Application
   public void
   onCreate ()
   {
+    /* Block signals which don't interest the current thread and its
+       descendants created by the system.  The original signal mask
+       will be restored for the Emacs thread in `initEmacs'.  */
+    EmacsNative.setupSystemThread ();
+
+    /* Locate a suitable dump file.  */
     findDumpFile (this);
+
+    /* Start the rest of the application.  */
     super.onCreate ();
   }
 };
diff --git a/java/org/gnu/emacs/EmacsService.java 
b/java/org/gnu/emacs/EmacsService.java
index 2fe4e8c4146..820befb52d2 100644
--- a/java/org/gnu/emacs/EmacsService.java
+++ b/java/org/gnu/emacs/EmacsService.java
@@ -25,7 +25,6 @@ import java.io.UnsupportedEncodingException;
 
 import java.util.List;
 
-import java.util.concurrent.Semaphore;
 import java.util.concurrent.atomic.AtomicInteger;
 
 import android.graphics.Matrix;
@@ -212,7 +211,6 @@ public final class EmacsService extends Service
     final String filesDir, libDir, cacheDir, classPath;
     final double pixelDensityX;
     final double pixelDensityY;
-    final Semaphore signalSemaphore;
 
     SERVICE = this;
     handler = new Handler (Looper.getMainLooper ());
@@ -222,7 +220,6 @@ public final class EmacsService extends Service
     pixelDensityX = metrics.xdpi;
     pixelDensityY = metrics.ydpi;
     resolver = getContentResolver ();
-    signalSemaphore = new Semaphore (0);
 
     try
       {
@@ -251,33 +248,11 @@ public final class EmacsService extends Service
                                          cacheDir, (float) pixelDensityX,
                                          (float) pixelDensityY,
                                          classPath, EmacsService.this);
-
-             /* Wait for the signal mask to be set up in the UI
-                thread.  */
-
-             while (true)
-               {
-                 try
-                   {
-                     signalSemaphore.acquire ();
-                     break;
-                   }
-                 catch (InterruptedException e)
-                   {
-                     ;;
-                   }
-               }
            }
          }, extraStartupArgument,
          /* If any file needs to be opened, open it now.  */
          EmacsOpenActivity.fileToOpen);
        thread.start ();
-
-       /* Now that the thread has been started, block signals which
-          don't interest the current thread.  */
-
-       EmacsNative.setupSystemThread ();
-       signalSemaphore.release ();
       }
     catch (IOException exception)
       {
diff --git a/src/android.c b/src/android.c
index ccc2da95f03..d6a56dfe0b8 100644
--- a/src/android.c
+++ b/src/android.c
@@ -261,6 +261,14 @@ void *unused_pointer;
 
 #endif /* __i386__ */
 
+/* Whether or not the default signal mask has been changed.  If so,
+   the signal mask must be restored before calling
+   android_emacs_init.  */
+static bool signal_mask_changed_p;
+
+/* The signal mask at the time Emacs was started.  */
+static sigset_t startup_signal_mask;
+
 
 
 /* Event handling functions.  Events are stored on a (circular) queue
@@ -2562,7 +2570,15 @@ NATIVE_NAME (initEmacs) (JNIEnv *env, jobject object, 
jarray argv,
   ANDROID_DELETE_LOCAL_REF (argv);
   ANDROID_DELETE_LOCAL_REF (dump_file_object);
 
+  /* Restore the signal mask at the time of startup if it was changed
+     to block unwanted signals from reaching system threads.  */
+
+  if (signal_mask_changed_p)
+    pthread_sigmask (SIG_SETMASK, &startup_signal_mask, NULL);
+
+  /* Now start Emacs proper.  */
   android_emacs_init (nelements, c_argv, dump_file);
+
   /* android_emacs_init should never return.  */
   emacs_abort ();
 }
@@ -3128,9 +3144,14 @@ NATIVE_NAME (setupSystemThread) (void)
   sigdelset (&sigset, SIGSEGV);
   sigdelset (&sigset, SIGBUS);
 
-  if (pthread_sigmask (SIG_BLOCK, &sigset, NULL))
+  /* Save the signal mask that was previously used.  It will be
+     restored in `initEmacs'.  */
+
+  if (pthread_sigmask (SIG_BLOCK, &sigset, &startup_signal_mask))
     __android_log_print (ANDROID_LOG_WARN, __func__,
                         "pthread_sigmask: %s", strerror (errno));
+  else
+    signal_mask_changed_p = true;
 }
 
 #ifdef __clang__