8296453: Simplify resource_area uses in ClassPathDirEntry::open_stream

Reviewed-by: dholmes, phh

Author: Xin Liu

src/hotspot/share/classfile/classLoader.cpp

@@ -255,7 +255,7 @@ ClassFileStream* ClassPathDirEntry::open_stream(JavaThread* current, const char*
     int file_handle = os::open(path, 0, 0);
     if (file_handle != -1) {
       // read contents into resource array
-      u1* buffer = NEW_RESOURCE_ARRAY(u1, st.st_size);
+      u1* buffer = NEW_RESOURCE_ARRAY_IN_THREAD(current, u1, st.st_size);
       size_t num_read = ::read(file_handle, (char*) buffer, st.st_size);
       // close file
       ::close(file_handle);
@@ -264,7 +264,11 @@ ClassFileStream* ClassPathDirEntry::open_stream(JavaThread* current, const char*
         if (UsePerfData) {
           ClassLoader::perf_sys_classfile_bytes_read()->inc(num_read);
         }
-        FREE_RESOURCE_ARRAY(char, path, path_len);
+#ifdef ASSERT
+        // Freeing path is a no-op here as buffer prevents it from being reclaimed. But we keep it for
+        // debug builds so that we guard against use-after-free bugs.
+        FREE_RESOURCE_ARRAY_IN_THREAD(current, char, path, path_len);
+#endif
         // Resource allocated
         return new ClassFileStream(buffer,
                                    st.st_size,
@@ -273,7 +277,7 @@ ClassFileStream* ClassPathDirEntry::open_stream(JavaThread* current, const char*
       }
     }
   }
-  FREE_RESOURCE_ARRAY(char, path, path_len);
+  FREE_RESOURCE_ARRAY_IN_THREAD(current, char, path, path_len);
   return NULL;
 }
 

src/hotspot/share/memory/allocation.hpp

@@ -423,7 +423,7 @@ extern char* resource_allocate_bytes(Thread* thread, size_t size,
     AllocFailType alloc_failmode = AllocFailStrategy::EXIT_OOM);
 extern char* resource_reallocate_bytes( char *old, size_t old_size, size_t new_size,
     AllocFailType alloc_failmode = AllocFailStrategy::EXIT_OOM);
-extern void resource_free_bytes( char *old, size_t size );
+extern void resource_free_bytes( Thread* thread, char *old, size_t size );
 
 //----------------------------------------------------------------------
 // Base class for objects allocated in the resource area.
@@ -548,7 +548,10 @@ class AnyObj {
                                     (new_size) * sizeof(type), AllocFailStrategy::RETURN_NULL)
 
 #define FREE_RESOURCE_ARRAY(type, old, size)\
-  resource_free_bytes((char*)(old), (size) * sizeof(type))
+  resource_free_bytes(Thread::current(), (char*)(old), (size) * sizeof(type))
+
+#define FREE_RESOURCE_ARRAY_IN_THREAD(thread, type, old, size)\
+  resource_free_bytes(thread, (char*)(old), (size) * sizeof(type))
 
 #define FREE_FAST(old)\
     /* nop */

src/hotspot/share/memory/resourceArea.cpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1997, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2022, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -74,6 +74,6 @@ extern char* resource_reallocate_bytes( char *old, size_t old_size, size_t new_s
   return (char*)Thread::current()->resource_area()->Arealloc(old, old_size, new_size, alloc_failmode);
 }
 
-extern void resource_free_bytes( char *old, size_t size ) {
-  Thread::current()->resource_area()->Afree(old, size);
+extern void resource_free_bytes( Thread* thread, char *old, size_t size ) {
+  thread->resource_area()->Afree(old, size);
 }

src/hotspot/share/utilities/stack.inline.hpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2009, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2009, 2022, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -252,7 +252,7 @@ E* ResourceStack<E, F>::alloc(size_t bytes)
 template <class E, MEMFLAGS F>
 void ResourceStack<E, F>::free(E* addr, size_t bytes)
 {
-  resource_free_bytes((char*) addr, bytes);
+  resource_free_bytes(Thread::current(), (char*) addr, bytes);
 }
 
 template <class E, MEMFLAGS F>