1 /*
2 * Copyright (C) 2017 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 <cinttypes>
18 #include <type_traits>
19
20 #include "chre/core/event_loop_manager.h"
21 #include "chre/core/host_comms_manager.h"
22 #include "chre/platform/assert.h"
23 #include "chre/platform/host_link.h"
24
25 namespace chre {
26
27 constexpr uint32_t kMessageToHostReservedFieldValue = UINT32_MAX;
28
flushMessagesSentByNanoapp(uint64_t appId)29 void HostCommsManager::flushMessagesSentByNanoapp(uint64_t appId) {
30 mHostLink.flushMessagesSentByNanoapp(appId);
31 }
32
sendMessageToHostFromNanoapp(Nanoapp * nanoapp,void * messageData,size_t messageSize,uint32_t messageType,uint16_t hostEndpoint,chreMessageFreeFunction * freeCallback)33 bool HostCommsManager::sendMessageToHostFromNanoapp(
34 Nanoapp *nanoapp, void *messageData, size_t messageSize,
35 uint32_t messageType, uint16_t hostEndpoint,
36 chreMessageFreeFunction *freeCallback) {
37 bool success = false;
38 if (messageSize > 0 && messageData == nullptr) {
39 LOGW("Rejecting malformed message (null data but non-zero size)");
40 } else if (messageSize > CHRE_MESSAGE_TO_HOST_MAX_SIZE) {
41 LOGW("Rejecting message of size %zu bytes (max %d)",
42 messageSize, CHRE_MESSAGE_TO_HOST_MAX_SIZE);
43 } else if (hostEndpoint == kHostEndpointUnspecified) {
44 LOGW("Rejecting message to invalid host endpoint");
45 } else {
46 MessageToHost *msgToHost = mMessagePool.allocate();
47
48 if (msgToHost == nullptr) {
49 LOG_OOM();
50 } else {
51 msgToHost->appId = nanoapp->getAppId();
52 msgToHost->message.wrap(static_cast<uint8_t *>(messageData), messageSize);
53 msgToHost->toHostData.hostEndpoint = hostEndpoint;
54 msgToHost->toHostData.messageType = messageType;
55 msgToHost->toHostData.nanoappFreeFunction = freeCallback;
56
57 // Populate a special value to help disambiguate message direction when
58 // debugging
59 msgToHost->toHostData.reserved = kMessageToHostReservedFieldValue;
60
61 success = mHostLink.sendMessage(msgToHost);
62 if (!success) {
63 mMessagePool.deallocate(msgToHost);
64 }
65 }
66 }
67
68 return success;
69 }
70
deliverNanoappMessageFromHost(uint64_t appId,uint16_t hostEndpoint,uint32_t messageType,const void * messageData,uint32_t messageSize,uint32_t targetInstanceId)71 void HostCommsManager::deliverNanoappMessageFromHost(
72 uint64_t appId, uint16_t hostEndpoint, uint32_t messageType,
73 const void *messageData, uint32_t messageSize, uint32_t targetInstanceId) {
74 bool success = false;
75
76 MessageFromHost *msgFromHost = mMessagePool.allocate();
77 if (msgFromHost == nullptr) {
78 LOG_OOM();
79 } else if (!msgFromHost->message.copy_array(
80 static_cast<const uint8_t *>(messageData), messageSize)) {
81 LOGE("Couldn't allocate %" PRIu32 " bytes for message data from host "
82 "(endpoint 0x%" PRIx16 " type %" PRIu32 ")", messageSize,
83 hostEndpoint, messageType);
84 } else {
85 msgFromHost->appId = appId;
86 msgFromHost->fromHostData.messageType = messageType;
87 msgFromHost->fromHostData.messageSize = static_cast<uint32_t>(
88 messageSize);
89 msgFromHost->fromHostData.message = msgFromHost->message.data();
90 msgFromHost->fromHostData.hostEndpoint = hostEndpoint;
91
92 success = EventLoopManagerSingleton::get()->getEventLoop().postEventOrDie(
93 CHRE_EVENT_MESSAGE_FROM_HOST, &msgFromHost->fromHostData,
94 freeMessageFromHostCallback, targetInstanceId);
95 }
96
97 if (!success && msgFromHost != nullptr) {
98 mMessagePool.deallocate(msgFromHost);
99 }
100 }
101
sendMessageToNanoappFromHost(uint64_t appId,uint32_t messageType,uint16_t hostEndpoint,const void * messageData,size_t messageSize)102 void HostCommsManager::sendMessageToNanoappFromHost(
103 uint64_t appId, uint32_t messageType, uint16_t hostEndpoint,
104 const void *messageData, size_t messageSize) {
105 const EventLoop& eventLoop = EventLoopManagerSingleton::get()
106 ->getEventLoop();
107 uint32_t targetInstanceId;
108
109 if (hostEndpoint == kHostEndpointBroadcast) {
110 LOGE("Received invalid message from host from broadcast endpoint");
111 } else if (messageSize > ((UINT32_MAX))) {
112 // The current CHRE API uses uint32_t to represent the message size in
113 // struct chreMessageFromHostData. We don't expect to ever need to exceed
114 // this, but the check ensures we're on the up and up.
115 LOGE("Rejecting message of size %zu (too big)", messageSize);
116 } else if (!eventLoop.findNanoappInstanceIdByAppId(appId,
117 &targetInstanceId)) {
118 LOGE("Dropping message; destination app ID 0x%016" PRIx64 " not found",
119 appId);
120 } else {
121 deliverNanoappMessageFromHost(appId, hostEndpoint, messageType, messageData,
122 static_cast<uint32_t>(messageSize),
123 targetInstanceId);
124 }
125 }
126
onMessageToHostComplete(const MessageToHost * message)127 void HostCommsManager::onMessageToHostComplete(const MessageToHost *message) {
128 // Removing const on message since we own the memory and will deallocate it;
129 // the caller (HostLink) only gets a const pointer
130 auto *msgToHost = const_cast<MessageToHost *>(message);
131
132 // If there's no free callback, we can free the message right away as the
133 // message pool is thread-safe; otherwise, we need to do it from within the
134 // EventLoop context.
135 if (msgToHost->toHostData.nanoappFreeFunction == nullptr) {
136 mMessagePool.deallocate(msgToHost);
137 } else {
138 auto freeMsgCallback = [](uint16_t /*type*/, void *data) {
139 EventLoopManagerSingleton::get()->getHostCommsManager().freeMessageToHost(
140 static_cast<MessageToHost *>(data));
141 };
142
143 EventLoopManagerSingleton::get()->deferCallback(
144 SystemCallbackType::MessageToHostComplete, msgToHost, freeMsgCallback);
145 }
146 }
147
freeMessageToHost(MessageToHost * msgToHost)148 void HostCommsManager::freeMessageToHost(MessageToHost *msgToHost) {
149 if (msgToHost->toHostData.nanoappFreeFunction != nullptr) {
150 EventLoopManagerSingleton::get()->getEventLoop().invokeMessageFreeFunction(
151 msgToHost->appId, msgToHost->toHostData.nanoappFreeFunction,
152 msgToHost->message.data(), msgToHost->message.size());
153 }
154 mMessagePool.deallocate(msgToHost);
155 }
156
freeMessageFromHostCallback(uint16_t,void * data)157 void HostCommsManager::freeMessageFromHostCallback(uint16_t /*type*/,
158 void *data) {
159 // We pass the chreMessageFromHostData structure to the nanoapp as the event's
160 // data pointer, but we need to return to the enclosing HostMessage pointer.
161 // As long as HostMessage is standard-layout, and fromHostData is the first
162 // field, we can convert between these two pointers via reinterpret_cast.
163 // These static assertions ensure this assumption is held.
164 static_assert(std::is_standard_layout<HostMessage>::value,
165 "HostMessage* is derived from HostMessage::fromHostData*, "
166 "therefore it must be standard layout");
167 static_assert(offsetof(MessageFromHost, fromHostData) == 0,
168 "fromHostData must be the first field in HostMessage");
169
170 auto *eventData = static_cast<chreMessageFromHostData *>(data);
171 auto *msgFromHost = reinterpret_cast<MessageFromHost *>(eventData);
172 auto& hostCommsMgr = EventLoopManagerSingleton::get()->getHostCommsManager();
173 hostCommsMgr.mMessagePool.deallocate(msgFromHost);
174 }
175
176
177 } // namespace chre
178