From a1869cb4a18b12f4c5a1bb6b69f8b0da24c28f73 Mon Sep 17 00:00:00 2001
From: hpi1 <hpi1@anonymous.org>
Date: Tue, 16 Apr 2019 12:37:13 +0300
Subject: [PATCH] Java 8+: Unconditionally hook java.io.FileSystem class

This is done during JVM boot stage
=> unsupported FileSystem implementation will prevent JVM boot.

Fixes skipping wrapper class sometimes when java.io.File.fs is static final.
---
 .../bdj/java/java/io/BDFileSystem.java        | 27 +++++-----
 .../bdj/java/java/io/DefaultFileSystem.java   | 51 +++++++++++++++++++
 2 files changed, 64 insertions(+), 14 deletions(-)
 create mode 100644 src/libbluray/bdj/java/java/io/DefaultFileSystem.java

diff --git a/src/libbluray/bdj/java/java/io/BDFileSystem.java b/src/libbluray/bdj/java/java/io/BDFileSystem.java
index aaa7d824..0ade43e0 100644
--- a/src/libbluray/bdj/java/java/io/BDFileSystem.java
+++ b/src/libbluray/bdj/java/java/io/BDFileSystem.java
@@ -50,18 +50,17 @@ public abstract class BDFileSystem extends FileSystem {
     private static FileSystem nativeFileSystem;
 
     static {
-        /* Java 8: getFileSystem() no longer exists on java.io.FileSystem */
         try {
-            nativeFileSystem = (FileSystem)Class.forName("java.io.DefaultFileSystem")
-                .getDeclaredMethod("getFileSystem", new Class[0])
+            /* Java < 8 */
+            nativeFileSystem = (FileSystem)FileSystem.class
+                .getDeclaredMethod("getFileSystem",new Class[0])
                 .invoke(null, new Object[0]);
         } catch (Exception e) {
             try {
-                nativeFileSystem = (FileSystem)FileSystem.class
-                    .getDeclaredMethod("getFileSystem",new Class[0])
-                    .invoke(null, new Object[0]);
-            } catch (Exception t) {
-                System.err.print("Couldn't find native filesystem: " + t);
+                /* Just use our wrapper.  If it fails, JVM won't be booted anyway ... */
+                nativeFileSystem = DefaultFileSystem.getNativeFileSystem();
+            } catch (Throwable t) {
+                System.err.print("Couldn't find native filesystem: " + e);
             }
         }
     }
@@ -77,7 +76,7 @@ public abstract class BDFileSystem extends FileSystem {
     }
 
     /*
-     * Replace File.fs for Xlets
+     * Replace File.fs for Xlets (required with Java < 8 where this is not done unconditionally)
      *
      * (called by org.videolan.BDJClassLoader)
      */
@@ -101,15 +100,15 @@ public abstract class BDFileSystem extends FileSystem {
             filesystem = c.getDeclaredField("fs");
             filesystem.setAccessible(true);
 
-            /* Java 8: remove "final" modifier from the field */
-            Field modifiersField = Field.class.getDeclaredField("modifiers");
-            modifiersField.setAccessible(true);
-            modifiersField.setInt(filesystem, filesystem.getModifiers() & ~Modifier.FINAL);
-
             FileSystem fs = (FileSystem)filesystem.get(null);
             if (fs instanceof BDFileSystemImpl) {
                 //System.err.print("FileSystem already wrapped");
             } else {
+                /* Java 8: we should never end up here ... */
+                /* Java 8: remove "final" modifier from the field */
+                //Field modifiersField = Field.class.getDeclaredField("modifiers");
+                //modifiersField.setAccessible(true);
+                //modifiersField.setInt(filesystem, filesystem.getModifiers() & ~Modifier.FINAL);
                 filesystem.set(null, new BDFileSystemImpl(fs));
             }
         } catch (Exception t) {
diff --git a/src/libbluray/bdj/java/java/io/DefaultFileSystem.java b/src/libbluray/bdj/java/java/io/DefaultFileSystem.java
new file mode 100644
index 00000000..8663128e
--- /dev/null
+++ b/src/libbluray/bdj/java/java/io/DefaultFileSystem.java
@@ -0,0 +1,51 @@
+/*
+ * This file is part of libbluray
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see
+ * <http://www.gnu.org/licenses/>.
+ */
+
+package java.io;
+
+class DefaultFileSystem {
+
+    static FileSystem getNativeFileSystem() {
+        Exception e1, e2, e3;
+        try {
+            return (FileSystem)Class.forName(System.getProperty("org.videolan.bdj_filesystem")).newInstance();
+        } catch (Exception e) {
+            e3 = e;
+        }
+        try {
+            return (FileSystem)Class.forName("java.io.UnixFileSystem").newInstance();
+        } catch (Exception e) {
+            e1 = e;
+        }
+        try {
+            return (FileSystem)Class.forName("java.io.WinNTFileSystem").newInstance();
+        } catch (Exception e) {
+            e2 = e;
+        }
+
+        /* No way to recover from here */
+        System.err.println("Unsupported native filesystem !\n\t" + e1 + "\n\t" + e2 + "\n\t" + e3);
+        //Runtime.getRuntime().halt(-1);
+        throw new Error("No filesystem implementation found");
+    }
+
+    public static FileSystem getFileSystem() {
+        FileSystem nativeFs = getNativeFileSystem();
+        return new BDFileSystemImpl(nativeFs);
+    }
+}