1 /*
2  * Copyright (C) 2016 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 #include "class_ext-inl.h"
18 
19 #include "art_method-inl.h"
20 #include "base/casts.h"
21 #include "base/enums.h"
22 #include "base/utils.h"
23 #include "class-inl.h"
24 #include "dex/dex_file-inl.h"
25 #include "gc/accounting/card_table-inl.h"
26 #include "object-inl.h"
27 #include "object_array.h"
28 #include "stack_trace_element.h"
29 #include "well_known_classes.h"
30 
31 namespace art {
32 namespace mirror {
33 
34 GcRoot<Class> ClassExt::dalvik_system_ClassExt_;
35 
ClassSize(PointerSize pointer_size)36 uint32_t ClassExt::ClassSize(PointerSize pointer_size) {
37   uint32_t vtable_entries = Object::kVTableLength;
38   return Class::ComputeClassSize(true, vtable_entries, 0, 0, 0, 0, 0, pointer_size);
39 }
40 
SetObsoleteArrays(ObjPtr<PointerArray> methods,ObjPtr<ObjectArray<DexCache>> dex_caches)41 void ClassExt::SetObsoleteArrays(ObjPtr<PointerArray> methods,
42                                  ObjPtr<ObjectArray<DexCache>> dex_caches) {
43   CHECK_EQ(methods.IsNull(), dex_caches.IsNull());
44   auto obsolete_dex_cache_off = OFFSET_OF_OBJECT_MEMBER(ClassExt, obsolete_dex_caches_);
45   auto obsolete_methods_off = OFFSET_OF_OBJECT_MEMBER(ClassExt, obsolete_methods_);
46   DCHECK(!Runtime::Current()->IsActiveTransaction());
47   SetFieldObject<false>(obsolete_dex_cache_off, dex_caches.Ptr());
48   SetFieldObject<false>(obsolete_methods_off, methods.Ptr());
49 }
50 
51 // We really need to be careful how we update this. If we ever in the future make it so that
52 // these arrays are written into without all threads being suspended we have a race condition! This
53 // race could cause obsolete methods to be missed.
ExtendObsoleteArrays(Thread * self,uint32_t increase)54 bool ClassExt::ExtendObsoleteArrays(Thread* self, uint32_t increase) {
55   // TODO It would be good to check that we have locked the class associated with this ClassExt.
56   StackHandleScope<5> hs(self);
57   Handle<ClassExt> h_this(hs.NewHandle(this));
58   Handle<PointerArray> old_methods(hs.NewHandle(h_this->GetObsoleteMethods()));
59   Handle<ObjectArray<DexCache>> old_dex_caches(hs.NewHandle(h_this->GetObsoleteDexCaches()));
60   ClassLinker* cl = Runtime::Current()->GetClassLinker();
61   size_t new_len;
62   if (old_methods == nullptr) {
63     CHECK(old_dex_caches == nullptr);
64     new_len = increase;
65   } else {
66     CHECK_EQ(old_methods->GetLength(), old_dex_caches->GetLength());
67     new_len = increase + old_methods->GetLength();
68   }
69   Handle<PointerArray> new_methods(hs.NewHandle<PointerArray>(
70       cl->AllocPointerArray(self, new_len)));
71   if (new_methods.IsNull()) {
72     // Fail.
73     self->AssertPendingOOMException();
74     return false;
75   }
76   Handle<ObjectArray<DexCache>> new_dex_caches(hs.NewHandle<ObjectArray<DexCache>>(
77       ObjectArray<DexCache>::Alloc(self,
78                                    cl->FindClass(self,
79                                                  "[Ljava/lang/DexCache;",
80                                                  ScopedNullHandle<ClassLoader>()),
81                                    new_len)));
82   if (new_dex_caches.IsNull()) {
83     // Fail.
84     self->AssertPendingOOMException();
85     return false;
86   }
87 
88   if (!old_methods.IsNull()) {
89     // Copy the old contents.
90     new_methods->Memcpy(0,
91                         old_methods.Get(),
92                         0,
93                         old_methods->GetLength(),
94                         cl->GetImagePointerSize());
95     new_dex_caches->AsObjectArray<Object>()->AssignableCheckingMemcpy<false>(
96         0, old_dex_caches->AsObjectArray<Object>(), 0, old_dex_caches->GetLength(), false);
97   }
98   // Set the fields.
99   h_this->SetObsoleteArrays(new_methods.Get(), new_dex_caches.Get());
100 
101   return true;
102 }
103 
Alloc(Thread * self)104 ClassExt* ClassExt::Alloc(Thread* self) {
105   DCHECK(dalvik_system_ClassExt_.Read() != nullptr);
106   return down_cast<ClassExt*>(dalvik_system_ClassExt_.Read()->AllocObject(self).Ptr());
107 }
108 
SetVerifyError(ObjPtr<Object> err)109 void ClassExt::SetVerifyError(ObjPtr<Object> err) {
110   if (Runtime::Current()->IsActiveTransaction()) {
111     SetFieldObject<true>(OFFSET_OF_OBJECT_MEMBER(ClassExt, verify_error_), err);
112   } else {
113     SetFieldObject<false>(OFFSET_OF_OBJECT_MEMBER(ClassExt, verify_error_), err);
114   }
115 }
116 
SetOriginalDexFile(ObjPtr<Object> bytes)117 void ClassExt::SetOriginalDexFile(ObjPtr<Object> bytes) {
118   DCHECK(!Runtime::Current()->IsActiveTransaction());
119   SetFieldObject<false>(OFFSET_OF_OBJECT_MEMBER(ClassExt, original_dex_file_), bytes);
120 }
121 
SetClass(ObjPtr<Class> dalvik_system_ClassExt)122 void ClassExt::SetClass(ObjPtr<Class> dalvik_system_ClassExt) {
123   CHECK(dalvik_system_ClassExt != nullptr);
124   dalvik_system_ClassExt_ = GcRoot<Class>(dalvik_system_ClassExt);
125 }
126 
ResetClass()127 void ClassExt::ResetClass() {
128   CHECK(!dalvik_system_ClassExt_.IsNull());
129   dalvik_system_ClassExt_ = GcRoot<Class>(nullptr);
130 }
131 
VisitRoots(RootVisitor * visitor)132 void ClassExt::VisitRoots(RootVisitor* visitor) {
133   dalvik_system_ClassExt_.VisitRootIfNonNull(visitor, RootInfo(kRootStickyClass));
134 }
135 
136 }  // namespace mirror
137 }  // namespace art
138