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 <android/binder_shell.h>
21 #include "ibinder_internal.h"
22
23 #include <atomic>
24 #include <mutex>
25 #include <optional>
26 #include <vector>
27
28 #include <binder/Binder.h>
29 #include <binder/IBinder.h>
30 #include <utils/Vector.h>
31
isUserCommand(transaction_code_t code)32 inline bool isUserCommand(transaction_code_t code) {
33 return code >= FIRST_CALL_TRANSACTION && code <= LAST_CALL_TRANSACTION;
34 }
35
36 struct ABBinder;
37 struct ABpBinder;
38
39 struct AIBinder : public virtual ::android::RefBase {
40 explicit AIBinder(const AIBinder_Class* clazz);
41 virtual ~AIBinder();
42
43 bool associateClass(const AIBinder_Class* clazz);
getClassAIBinder44 const AIBinder_Class* getClass() const { return mClazz; }
45
46 virtual ::android::sp<::android::IBinder> getBinder() = 0;
asABBinderAIBinder47 virtual ABBinder* asABBinder() { return nullptr; }
asABpBinderAIBinder48 virtual ABpBinder* asABpBinder() { return nullptr; }
49
isRemoteAIBinder50 bool isRemote() const {
51 ::android::sp<::android::IBinder> binder = const_cast<AIBinder*>(this)->getBinder();
52 return binder->remoteBinder() != nullptr;
53 }
54
55 private:
56 std::optional<bool> associateClassInternal(const AIBinder_Class* clazz,
57 const ::android::String16& newDescriptor, bool set);
58
59 // AIBinder instance is instance of this class for a local object. In order to transact on a
60 // remote object, this also must be set for simplicity (although right now, only the
61 // interfaceDescriptor from it is used).
62 const AIBinder_Class* mClazz;
63 std::mutex mClazzMutex;
64 };
65
66 // This is a local AIBinder object with a known class.
67 struct ABBinder : public AIBinder, public ::android::BBinder {
68 virtual ~ABBinder();
69
getUserDataABBinder70 void* getUserData() { return mUserData; }
71
getBinderABBinder72 ::android::sp<::android::IBinder> getBinder() override { return this; }
asABBinderABBinder73 ABBinder* asABBinder() override { return this; }
74
75 const ::android::String16& getInterfaceDescriptor() const override;
76 ::android::status_t dump(int fd, const ::android::Vector<::android::String16>& args) override;
77 ::android::status_t onTransact(uint32_t code, const ::android::Parcel& data,
78 ::android::Parcel* reply, binder_flags_t flags) override;
79
80 private:
81 ABBinder(const AIBinder_Class* clazz, void* userData);
82
83 // only thing that should create an ABBinder
84 friend AIBinder* AIBinder_new(const AIBinder_Class*, void*);
85
86 // Can contain implementation if this is a local binder. This can still be nullptr for a local
87 // binder. If it is nullptr, the implication is the implementation state is entirely external to
88 // this object and the functionality provided in the AIBinder_Class is sufficient.
89 void* mUserData;
90 };
91
92 // This binder object may be remote or local (even though it is 'Bp'). The implication if it is
93 // local is that it is an IBinder object created outside of the domain of libbinder_ndk.
94 struct ABpBinder : public AIBinder, public ::android::BpRefBase {
95 // Looks up to see if this object has or is an existing ABBinder or ABpBinder object, otherwise
96 // it creates an ABpBinder object.
97 static ::android::sp<AIBinder> lookupOrCreateFromBinder(
98 const ::android::sp<::android::IBinder>& binder);
99
100 virtual ~ABpBinder();
101
102 void onLastStrongRef(const void* id) override;
103
getBinderABpBinder104 ::android::sp<::android::IBinder> getBinder() override { return remote(); }
asABpBinderABpBinder105 ABpBinder* asABpBinder() override { return this; }
106
107 private:
108 explicit ABpBinder(const ::android::sp<::android::IBinder>& binder);
109 };
110
111 struct AIBinder_Class {
112 AIBinder_Class(const char* interfaceDescriptor, AIBinder_Class_onCreate onCreate,
113 AIBinder_Class_onDestroy onDestroy, AIBinder_Class_onTransact onTransact);
114
getInterfaceDescriptorAIBinder_Class115 const ::android::String16& getInterfaceDescriptor() const { return mWideInterfaceDescriptor; }
getInterfaceDescriptorUtf8AIBinder_Class116 const char* getInterfaceDescriptorUtf8() const { return mInterfaceDescriptor.c_str(); }
117
118 // required to be non-null, implemented for every class
119 const AIBinder_Class_onCreate onCreate = nullptr;
120 const AIBinder_Class_onDestroy onDestroy = nullptr;
121 const AIBinder_Class_onTransact onTransact = nullptr;
122
123 // optional methods for a class
124 AIBinder_onDump onDump = nullptr;
125 AIBinder_handleShellCommand handleShellCommand = nullptr;
126
127 private:
128 // Copy of the raw char string for when we don't have to return UTF-16
129 const std::string mInterfaceDescriptor;
130 // This must be a String16 since BBinder virtual getInterfaceDescriptor returns a reference to
131 // one.
132 const ::android::String16 mWideInterfaceDescriptor;
133 };
134
135 // Ownership is like this (when linked to death):
136 //
137 // AIBinder_DeathRecipient -sp-> TransferDeathRecipient <-wp-> IBinder
138 //
139 // When the AIBinder_DeathRecipient is dropped, so are the actual underlying death recipients. When
140 // the IBinder dies, only a wp to it is kept.
141 struct AIBinder_DeathRecipient : ::android::RefBase {
142 // One of these is created for every linkToDeath. This is to be able to recover data when a
143 // binderDied receipt only gives us information about the IBinder.
144 struct TransferDeathRecipient : ::android::IBinder::DeathRecipient {
TransferDeathRecipientAIBinder_DeathRecipient::TransferDeathRecipient145 TransferDeathRecipient(const ::android::wp<::android::IBinder>& who, void* cookie,
146 const ::android::wp<AIBinder_DeathRecipient>& parentRecipient,
147 const AIBinder_DeathRecipient_onBinderDied onDied)
148 : mWho(who), mCookie(cookie), mParentRecipient(parentRecipient), mOnDied(onDied) {}
149
150 void binderDied(const ::android::wp<::android::IBinder>& who) override;
151
getWhoAIBinder_DeathRecipient::TransferDeathRecipient152 const ::android::wp<::android::IBinder>& getWho() { return mWho; }
getCookieAIBinder_DeathRecipient::TransferDeathRecipient153 void* getCookie() { return mCookie; }
154
155 private:
156 ::android::wp<::android::IBinder> mWho;
157 void* mCookie;
158
159 ::android::wp<AIBinder_DeathRecipient> mParentRecipient;
160
161 // This is kept separately from AIBinder_DeathRecipient in case the death recipient is
162 // deleted while the death notification is fired
163 const AIBinder_DeathRecipient_onBinderDied mOnDied;
164 };
165
166 explicit AIBinder_DeathRecipient(AIBinder_DeathRecipient_onBinderDied onDied);
167 binder_status_t linkToDeath(const ::android::sp<::android::IBinder>&, void* cookie);
168 binder_status_t unlinkToDeath(const ::android::sp<::android::IBinder>& binder, void* cookie);
169
170 private:
171 // When the user of this API deletes a Bp object but not the death recipient, the
172 // TransferDeathRecipient object can't be cleaned up. This is called whenever a new
173 // TransferDeathRecipient is linked, and it ensures that mDeathRecipients can't grow unbounded.
174 void pruneDeadTransferEntriesLocked();
175
176 std::mutex mDeathRecipientsMutex;
177 std::vector<::android::sp<TransferDeathRecipient>> mDeathRecipients;
178 AIBinder_DeathRecipient_onBinderDied mOnDied;
179 };
180