2 * Copyright (C) 2011 The Android Open Source Project
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
8 * http://www.apache.org/licenses/LICENSE-2.0
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.
17 #ifndef ART_RUNTIME_JNI_ENV_EXT_H_
18 #define ART_RUNTIME_JNI_ENV_EXT_H_
22 #include "base/macros.h"
23 #include "base/mutex.h"
24 #include "indirect_reference_table.h"
25 #include "object_callbacks.h"
26 #include "reference_table.h"
32 // Number of local references in the indirect reference table. The value is arbitrary but
33 // low enough that it forces sanity checks.
34 static constexpr size_t kLocalsInitial = 512;
36 struct JNIEnvExt : public JNIEnv {
37 // Creates a new JNIEnvExt. Returns null on error, in which case error_msg
38 // will contain a description of the error.
39 static JNIEnvExt* Create(Thread* self, JavaVMExt* vm, std::string* error_msg);
43 void DumpReferenceTables(std::ostream& os)
44 REQUIRES_SHARED(Locks::mutator_lock_);
46 void SetCheckJniEnabled(bool enabled) REQUIRES(!Locks::jni_function_table_lock_);
48 void PushFrame(int capacity) REQUIRES_SHARED(Locks::mutator_lock_);
49 void PopFrame() REQUIRES_SHARED(Locks::mutator_lock_);
52 T AddLocalReference(ObjPtr<mirror::Object> obj) REQUIRES_SHARED(Locks::mutator_lock_);
54 static Offset SegmentStateOffset(size_t pointer_size);
55 static Offset LocalRefCookieOffset(size_t pointer_size);
56 static Offset SelfOffset(size_t pointer_size);
58 static jint GetEnvHandler(JavaVMExt* vm, /*out*/void** out, jint version);
60 jobject NewLocalRef(mirror::Object* obj) REQUIRES_SHARED(Locks::mutator_lock_);
61 void DeleteLocalRef(jobject obj) REQUIRES_SHARED(Locks::mutator_lock_);
66 // Cookie used when using the local indirect reference table.
67 IRTSegmentState local_ref_cookie;
69 // JNI local references.
70 IndirectReferenceTable locals GUARDED_BY(Locks::mutator_lock_);
72 // Stack of cookies corresponding to PushLocalFrame/PopLocalFrame calls.
73 // TODO: to avoid leaks (and bugs), we need to clear this vector on entry (or return)
74 // to a native method.
75 std::vector<IRTSegmentState> stacked_local_ref_cookies;
77 // Frequently-accessed fields cached from JavaVM.
80 // If we are a JNI env for a daemon thread with a deleted runtime.
83 // How many nested "critical" JNI calls are we in?
86 // Entered JNI monitors, for bulk exit on thread detach.
87 ReferenceTable monitors;
89 // Used by -Xcheck:jni.
90 const JNINativeInterface* unchecked_functions;
92 // Functions to keep track of monitor lock and unlock operations. Used to ensure proper locking
93 // rules in CheckJNI mode.
95 // Record locking of a monitor.
96 void RecordMonitorEnter(jobject obj) REQUIRES_SHARED(Locks::mutator_lock_);
98 // Check the release, that is, that the release is performed in the same JNI "segment."
99 void CheckMonitorRelease(jobject obj) REQUIRES_SHARED(Locks::mutator_lock_);
101 // Check that no monitors are held that have been acquired in this JNI "segment."
102 void CheckNoHeldMonitors() REQUIRES_SHARED(Locks::mutator_lock_);
104 // Set the functions to the runtime shutdown functions.
105 void SetFunctionsToRuntimeShutdownFunctions();
107 // Set the function table override. This will install the override (or original table, if null)
109 // Note: JNI function table overrides are sensitive to the order of operations wrt/ CheckJNI.
110 // After overriding the JNI function table, CheckJNI toggling is ignored.
111 static void SetTableOverride(const JNINativeInterface* table_override)
112 REQUIRES(!Locks::thread_list_lock_, !Locks::jni_function_table_lock_);
114 // Return either the regular, or the CheckJNI function table. Will return table_override_ instead
115 // if it is not null.
116 static const JNINativeInterface* GetFunctionTable(bool check_jni)
117 REQUIRES(Locks::jni_function_table_lock_);
120 // Override of function tables. This applies to both default as well as instrumented (CheckJNI)
122 static const JNINativeInterface* table_override_ GUARDED_BY(Locks::jni_function_table_lock_);
124 // The constructor should not be called directly. It may leave the object in an erroneous state,
125 // and the result needs to be checked.
126 JNIEnvExt(Thread* self, JavaVMExt* vm, std::string* error_msg)
127 REQUIRES(!Locks::jni_function_table_lock_);
129 // All locked objects, with the (Java caller) stack frame that locked them. Used in CheckJNI
130 // to ensure that only monitors locked in this native frame are being unlocked, and that at
131 // the end all are unlocked.
132 std::vector<std::pair<uintptr_t, jobject>> locked_objects_;
135 // Used to save and restore the JNIEnvExt state when not going through code created by the JNI
137 class ScopedJniEnvLocalRefState {
139 explicit ScopedJniEnvLocalRefState(JNIEnvExt* env) : env_(env) {
140 saved_local_ref_cookie_ = env->local_ref_cookie;
141 env->local_ref_cookie = env->locals.GetSegmentState();
144 ~ScopedJniEnvLocalRefState() {
145 env_->locals.SetSegmentState(env_->local_ref_cookie);
146 env_->local_ref_cookie = saved_local_ref_cookie_;
150 JNIEnvExt* const env_;
151 IRTSegmentState saved_local_ref_cookie_;
153 DISALLOW_COPY_AND_ASSIGN(ScopedJniEnvLocalRefState);
158 #endif // ART_RUNTIME_JNI_ENV_EXT_H_