1 /*
2 * Copyright (C) 2018 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 #pragma once
18
19 #include <android/binder_ibinder.h>
20 #include "ibinder_internal.h"
21
22 #include <atomic>
23 #include <mutex>
24 #include <vector>
25
26 #include <binder/Binder.h>
27 #include <binder/IBinder.h>
28 #include <utils/Vector.h>
29
isUserCommand(transaction_code_t code)30 inline bool isUserCommand(transaction_code_t code) {
31 return code >= FIRST_CALL_TRANSACTION && code <= LAST_CALL_TRANSACTION;
32 }
33
34 struct ABBinder;
35 struct ABpBinder;
36
37 struct AIBinder : public virtual ::android::RefBase {
38 explicit AIBinder(const AIBinder_Class* clazz);
39 virtual ~AIBinder();
40
41 bool associateClass(const AIBinder_Class* clazz);
getClassAIBinder42 const AIBinder_Class* getClass() const { return mClazz; }
43
44 virtual ::android::sp<::android::IBinder> getBinder() = 0;
asABBinderAIBinder45 virtual ABBinder* asABBinder() { return nullptr; }
asABpBinderAIBinder46 virtual ABpBinder* asABpBinder() { return nullptr; }
47
isRemoteAIBinder48 bool isRemote() const {
49 ::android::sp<::android::IBinder> binder = const_cast<AIBinder*>(this)->getBinder();
50 return binder->remoteBinder() != nullptr;
51 }
52
53 private:
54 // AIBinder instance is instance of this class for a local object. In order to transact on a
55 // remote object, this also must be set for simplicity (although right now, only the
56 // interfaceDescriptor from it is used).
57 const AIBinder_Class* mClazz;
58 };
59
60 // This is a local AIBinder object with a known class.
61 struct ABBinder : public AIBinder, public ::android::BBinder {
62 virtual ~ABBinder();
63
getUserDataABBinder64 void* getUserData() { return mUserData; }
65
getBinderABBinder66 ::android::sp<::android::IBinder> getBinder() override { return this; }
asABBinderABBinder67 ABBinder* asABBinder() override { return this; }
68
69 const ::android::String16& getInterfaceDescriptor() const override;
70 ::android::status_t dump(int fd, const ::android::Vector<::android::String16>& args) override;
71 ::android::status_t onTransact(uint32_t code, const ::android::Parcel& data,
72 ::android::Parcel* reply, binder_flags_t flags) override;
73
74 private:
75 ABBinder(const AIBinder_Class* clazz, void* userData);
76
77 // only thing that should create an ABBinder
78 friend AIBinder* AIBinder_new(const AIBinder_Class*, void*);
79
80 // Can contain implementation if this is a local binder. This can still be nullptr for a local
81 // binder. If it is nullptr, the implication is the implementation state is entirely external to
82 // this object and the functionality provided in the AIBinder_Class is sufficient.
83 void* mUserData;
84 };
85
86 // This binder object may be remote or local (even though it is 'Bp'). The implication if it is
87 // local is that it is an IBinder object created outside of the domain of libbinder_ndk.
88 struct ABpBinder : public AIBinder, public ::android::BpRefBase {
89 // Looks up to see if this object has or is an existing ABBinder or ABpBinder object, otherwise
90 // it creates an ABpBinder object.
91 static ::android::sp<AIBinder> lookupOrCreateFromBinder(
92 const ::android::sp<::android::IBinder>& binder);
93
94 virtual ~ABpBinder();
95
96 void onLastStrongRef(const void* id) override;
97
getBinderABpBinder98 ::android::sp<::android::IBinder> getBinder() override { return remote(); }
asABpBinderABpBinder99 ABpBinder* asABpBinder() override { return this; }
100
101 private:
102 explicit ABpBinder(const ::android::sp<::android::IBinder>& binder);
103 };
104
105 struct AIBinder_Class {
106 AIBinder_Class(const char* interfaceDescriptor, AIBinder_Class_onCreate onCreate,
107 AIBinder_Class_onDestroy onDestroy, AIBinder_Class_onTransact onTransact);
108
getInterfaceDescriptorAIBinder_Class109 const ::android::String16& getInterfaceDescriptor() const { return mInterfaceDescriptor; }
110
111 // required to be non-null, implemented for every class
112 const AIBinder_Class_onCreate onCreate;
113 const AIBinder_Class_onDestroy onDestroy;
114 const AIBinder_Class_onTransact onTransact;
115
116 // optional methods for a class
117 AIBinder_onDump onDump;
118
119 private:
120 // This must be a String16 since BBinder virtual getInterfaceDescriptor returns a reference to
121 // one.
122 const ::android::String16 mInterfaceDescriptor;
123 };
124
125 // Ownership is like this (when linked to death):
126 //
127 // AIBinder_DeathRecipient -sp-> TransferDeathRecipient <-wp-> IBinder
128 //
129 // When the AIBinder_DeathRecipient is dropped, so are the actual underlying death recipients. When
130 // the IBinder dies, only a wp to it is kept.
131 struct AIBinder_DeathRecipient : ::android::RefBase {
132 // One of these is created for every linkToDeath. This is to be able to recover data when a
133 // binderDied receipt only gives us information about the IBinder.
134 struct TransferDeathRecipient : ::android::IBinder::DeathRecipient {
TransferDeathRecipientAIBinder_DeathRecipient::TransferDeathRecipient135 TransferDeathRecipient(const ::android::wp<::android::IBinder>& who, void* cookie,
136 const ::android::wp<AIBinder_DeathRecipient>& parentRecipient,
137 const AIBinder_DeathRecipient_onBinderDied onDied)
138 : mWho(who), mCookie(cookie), mParentRecipient(parentRecipient), mOnDied(onDied) {}
139
140 void binderDied(const ::android::wp<::android::IBinder>& who) override;
141
getWhoAIBinder_DeathRecipient::TransferDeathRecipient142 const ::android::wp<::android::IBinder>& getWho() { return mWho; }
getCookieAIBinder_DeathRecipient::TransferDeathRecipient143 void* getCookie() { return mCookie; }
144
145 private:
146 ::android::wp<::android::IBinder> mWho;
147 void* mCookie;
148
149 ::android::wp<AIBinder_DeathRecipient> mParentRecipient;
150
151 // This is kept separately from AIBinder_DeathRecipient in case the death recipient is
152 // deleted while the death notification is fired
153 const AIBinder_DeathRecipient_onBinderDied mOnDied;
154 };
155
156 explicit AIBinder_DeathRecipient(AIBinder_DeathRecipient_onBinderDied onDied);
157 binder_status_t linkToDeath(::android::sp<::android::IBinder>, void* cookie);
158 binder_status_t unlinkToDeath(::android::sp<::android::IBinder> binder, void* cookie);
159
160 private:
161 // When the user of this API deletes a Bp object but not the death recipient, the
162 // TransferDeathRecipient object can't be cleaned up. This is called whenever a new
163 // TransferDeathRecipient is linked, and it ensures that mDeathRecipients can't grow unbounded.
164 void pruneDeadTransferEntriesLocked();
165
166 std::mutex mDeathRecipientsMutex;
167 std::vector<::android::sp<TransferDeathRecipient>> mDeathRecipients;
168 AIBinder_DeathRecipient_onBinderDied mOnDied;
169 };
170