JniInternal.h revision 92fa476a8802023b443af893817eb14fef18aaea 
1/*
2 * Copyright (C) 2008 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 * JNI innards, common to the regular and "checked" interfaces.
18 */
19#ifndef _DALVIK_JNIINTERNAL
20#define _DALVIK_JNIINTERNAL
21
22#include "jni.h"
23
24/* system init/shutdown */
25bool dvmJniStartup(void);
26void dvmJniShutdown(void);
27
28/*
29 * Our data structures for JNIEnv and JavaVM.
30 *
31 * Native code thinks it has a pointer to a pointer.  We know better.
32 */
33struct JavaVMExt;
34
35typedef struct JNIEnvExt {
36    const struct JNINativeInterface* funcTable;     /* must be first */
37
38    const struct JNINativeInterface* baseFuncTable;
39
40    /* pointer to the VM we are a part of */
41    struct JavaVMExt* vm;
42
43    u4      envThreadId;
44    Thread* self;
45
46    /* if nonzero, we are in a "critical" JNI call */
47    int     critical;
48
49    /* keep a copy of this here for speed */
50    bool    forceDataCopy;
51
52    struct JNIEnvExt* prev;
53    struct JNIEnvExt* next;
54} JNIEnvExt;
55
56typedef struct JavaVMExt {
57    const struct JNIInvokeInterface* funcTable;     /* must be first */
58
59    const struct JNIInvokeInterface* baseFuncTable;
60
61    /* if multiple VMs are desired, add doubly-linked list stuff here */
62
63    /* per-VM feature flags */
64    bool    useChecked;
65    bool    warnError;
66    bool    forceDataCopy;
67
68    /* head of list of JNIEnvs associated with this VM */
69    JNIEnvExt*      envList;
70    pthread_mutex_t envListLock;
71} JavaVMExt;
72
73/*
74 * Native function return type; used by dvmPlatformInvoke().
75 *
76 * This is part of Method.jniArgInfo, and must fit in 3 bits.
77 * Note: Assembly code in arch/<arch>/Call<arch>.S relies on
78 * the enum values defined here.
79 */
80typedef enum DalvikJniReturnType {
81    DALVIK_JNI_RETURN_VOID = 0,     /* must be zero */
82    DALVIK_JNI_RETURN_FLOAT = 1,
83    DALVIK_JNI_RETURN_DOUBLE = 2,
84    DALVIK_JNI_RETURN_S8 = 3,
85    DALVIK_JNI_RETURN_S4 = 4,
86    DALVIK_JNI_RETURN_S2 = 5,
87    DALVIK_JNI_RETURN_U2 = 6,
88    DALVIK_JNI_RETURN_S1 = 7
89} DalvikJniReturnType;
90
91#define DALVIK_JNI_NO_ARG_INFO  0x80000000
92#define DALVIK_JNI_RETURN_MASK  0x70000000
93#define DALVIK_JNI_RETURN_SHIFT 28
94#define DALVIK_JNI_COUNT_MASK   0x0f000000
95#define DALVIK_JNI_COUNT_SHIFT  24
96
97
98/*
99 * Pop the JNI local stack when we return from a native method.  "saveArea"
100 * points to the StackSaveArea for the method we're leaving.
101 *
102 * (This may be implemented directly in assembly in mterp, so changes here
103 * may only affect the portable interpreter.)
104 */
105INLINE void dvmPopJniLocals(Thread* self, StackSaveArea* saveArea)
106{
107#ifdef USE_INDIRECT_REF
108    self->jniLocalRefTable.segmentState.all = saveArea->xtra.localRefCookie;
109#else
110    self->jniLocalRefTable.nextEntry = saveArea->xtra.localRefCookie;
111#endif
112}
113
114/*
115 * Set the envThreadId field.
116 */
117INLINE void dvmSetJniEnvThreadId(JNIEnv* pEnv, Thread* self)
118{
119    ((JNIEnvExt*)pEnv)->envThreadId = self->threadId;
120    ((JNIEnvExt*)pEnv)->self = self;
121}
122
123/*
124 * JNI call bridges.  Not called directly.
125 *
126 * The "Check" versions are used when CheckJNI is enabled.
127 */
128void dvmCallJNIMethod_general(const u4* args, JValue* pResult,
129    const Method* method, Thread* self);
130void dvmCallJNIMethod_synchronized(const u4* args, JValue* pResult,
131    const Method* method, Thread* self);
132void dvmCallJNIMethod_virtualNoRef(const u4* args, JValue* pResult,
133    const Method* method, Thread* self);
134void dvmCallJNIMethod_staticNoRef(const u4* args, JValue* pResult,
135    const Method* method, Thread* self);
136void dvmCheckCallJNIMethod_general(const u4* args, JValue* pResult,
137    const Method* method, Thread* self);
138void dvmCheckCallJNIMethod_synchronized(const u4* args, JValue* pResult,
139    const Method* method, Thread* self);
140void dvmCheckCallJNIMethod_virtualNoRef(const u4* args, JValue* pResult,
141    const Method* method, Thread* self);
142void dvmCheckCallJNIMethod_staticNoRef(const u4* args, JValue* pResult,
143    const Method* method, Thread* self);
144
145/*
146 * Configure "method" to use the JNI bridge to call "func".
147 */
148void dvmUseJNIBridge(Method* method, void* func);
149
150
151/*
152 * Enable the "checked" versions.
153 */
154void dvmUseCheckedJniEnv(JNIEnvExt* pEnv);
155void dvmUseCheckedJniVm(JavaVMExt* pVm);
156void dvmLateEnableCheckedJni(void);
157
158/*
159 * Decode a local, global, or weak-global reference.
160 */
161#ifdef USE_INDIRECT_REF
162Object* dvmDecodeIndirectRef(JNIEnv* env, jobject jobj);
163#else
164/* use an inline to ensure this is a no-op */
165INLINE Object* dvmDecodeIndirectRef(JNIEnv* env, jobject jobj) {
166    return (Object*) jobj;
167}
168#endif
169
170/*
171 * Verify that a reference passed in from native code is valid.  Returns
172 * an indication of local/global/invalid.
173 */
174jobjectRefType dvmGetJNIRefType(JNIEnv* env, jobject jobj);
175
176/*
177 * Get the last method called on the interp stack.  This is the method
178 * "responsible" for calling into JNI.
179 */
180const Method* dvmGetCurrentJNIMethod(void);
181
182/*
183 * Create/destroy a JNIEnv for the current thread.
184 */
185JNIEnv* dvmCreateJNIEnv(Thread* self);
186void dvmDestroyJNIEnv(JNIEnv* env);
187
188/*
189 * Find the JNIEnv associated with the current thread.
190 */
191JNIEnvExt* dvmGetJNIEnvForThread(void);
192
193/*
194 * Extract the return type enum from the "jniArgInfo" value.
195 */
196DalvikJniReturnType dvmGetArgInfoReturnType(int jniArgInfo);
197
198/*
199 * Release all MonitorEnter-acquired locks that are still held.  Called at
200 * DetachCurrentThread time.
201 */
202void dvmReleaseJniMonitors(Thread* self);
203
204/*
205 * Dump the contents of the JNI reference tables to the log file.
206 *
207 * The local ref tables associated with other threads are not included.
208 */
209void dvmDumpJniReferenceTables(void);
210
211/*
212 * This mask is applied to weak global reference values returned to
213 * native code.  The goal is to create an invalid pointer that will cause
214 * a crash if misused.  The mmap region for the virtual heap is typically
215 * around 0x40xxxxxx.
216 *
217 * To make weak global references easily distinguishable from other kinds
218 * of references when !USE_INDIRECT_REF, we XOR the low bits.  Assuming >=
219 * 64-bit alignment of objects, this changes the low 3 bits from all clear
220 * to all set.
221 */
222#define WEAK_GLOBAL_XOR 0x9e0fffff
223
224/*
225 * "Obfuscate" a weak global reference pointer.
226 */
227INLINE jweak dvmObfuscateWeakGlobalRef(jobject jobj) {
228    return (jweak) ((u4) jobj ^ WEAK_GLOBAL_XOR);
229}
230
231/*
232 * Undo the obfuscation.
233 */
234INLINE jobject dvmNormalizeWeakGlobalRef(jweak ref) {
235    return (jobject) ((u4) ref ^ WEAK_GLOBAL_XOR);
236}
237
238/*
239 * Returns "true" if this looks like a weak global reference.
240 *
241 * Relies on the low 3 bits being set instead of clear (the latter is
242 * guaranteed by 64-bit alignment of objects).
243 */
244INLINE bool dvmIsWeakGlobalRef(jobject jobj) {
245    return (((u4) jobj & 0x07) == 0x07);
246}
247
248#endif /*_DALVIK_JNIINTERNAL*/
249