1 /*
2 * Copyright (C) 2013 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 #define LOG_TAG "MediaLog"
18 //#define LOG_NDEBUG 0
19
20 #include <sys/mman.h>
21 #include <utils/Log.h>
22 #include <binder/PermissionCache.h>
23 #include <media/nblog/NBLog.h>
24 #include <private/android_filesystem_config.h>
25 #include "MediaLogService.h"
26
27 namespace android {
28
29 static const char kDeadlockedString[] = "MediaLogService may be deadlocked\n";
30
31 // mMerger, mMergeReader, and mMergeThread all point to the same location in memory
32 // mMergerShared. This is the local memory FIFO containing data merged from all
33 // individual thread FIFOs in shared memory. mMergeThread is used to periodically
34 // call NBLog::Merger::merge() to collect the data and write it to the FIFO, and call
35 // NBLog::MergeReader::getAndProcessSnapshot to process the merged data.
MediaLogService()36 MediaLogService::MediaLogService() :
37 BnMediaLogService(),
38 mMergerShared((NBLog::Shared*) malloc(NBLog::Timeline::sharedSize(kMergeBufferSize))),
39 mMerger(mMergerShared, kMergeBufferSize),
40 mMergeReader(mMergerShared, kMergeBufferSize, mMerger),
41 mMergeThread(new NBLog::MergeThread(mMerger, mMergeReader))
42 {
43 mMergeThread->run("MergeThread");
44 }
45
~MediaLogService()46 MediaLogService::~MediaLogService()
47 {
48 mMergeThread->requestExit();
49 mMergeThread->setTimeoutUs(0);
50 mMergeThread->join();
51 free(mMergerShared);
52 }
53
registerWriter(const sp<IMemory> & shared,size_t size,const char * name)54 void MediaLogService::registerWriter(const sp<IMemory>& shared, size_t size, const char *name)
55 {
56 if (IPCThreadState::self()->getCallingUid() != AID_AUDIOSERVER || shared == 0 ||
57 size < kMinSize || size > kMaxSize || name == NULL ||
58 shared->size() < NBLog::Timeline::sharedSize(size)) {
59 return;
60 }
61 sp<NBLog::Reader> reader(new NBLog::Reader(shared, size));
62 NBLog::NamedReader namedReader(reader, name);
63 Mutex::Autolock _l(mLock);
64 mNamedReaders.add(namedReader);
65 mMerger.addReader(namedReader);
66 }
67
unregisterWriter(const sp<IMemory> & shared)68 void MediaLogService::unregisterWriter(const sp<IMemory>& shared)
69 {
70 if (IPCThreadState::self()->getCallingUid() != AID_AUDIOSERVER || shared == 0) {
71 return;
72 }
73 Mutex::Autolock _l(mLock);
74 for (size_t i = 0; i < mNamedReaders.size(); ) {
75 if (mNamedReaders[i].reader()->isIMemory(shared)) {
76 mNamedReaders.removeAt(i);
77 } else {
78 i++;
79 }
80 }
81 }
82
dumpTryLock(Mutex & mutex)83 bool MediaLogService::dumpTryLock(Mutex& mutex)
84 {
85 bool locked = false;
86 for (int i = 0; i < kDumpLockRetries; ++i) {
87 if (mutex.tryLock() == NO_ERROR) {
88 locked = true;
89 break;
90 }
91 usleep(kDumpLockSleepUs);
92 }
93 return locked;
94 }
95
dump(int fd,const Vector<String16> & args __unused)96 status_t MediaLogService::dump(int fd, const Vector<String16>& args __unused)
97 {
98 // FIXME merge with similar but not identical code at services/audioflinger/ServiceUtilities.cpp
99 static const String16 sDump("android.permission.DUMP");
100 if (!(IPCThreadState::self()->getCallingUid() == AID_AUDIOSERVER ||
101 PermissionCache::checkCallingPermission(sDump))) {
102 dprintf(fd, "Permission Denial: can't dump media.log from pid=%d, uid=%d\n",
103 IPCThreadState::self()->getCallingPid(),
104 IPCThreadState::self()->getCallingUid());
105 return NO_ERROR;
106 }
107
108 if (args.size() > 0) {
109 const String8 arg0(args[0]);
110 if (!strcmp(arg0.string(), "-r")) {
111 // needed because mNamedReaders is protected by mLock
112 bool locked = dumpTryLock(mLock);
113
114 // failed to lock - MediaLogService is probably deadlocked
115 if (!locked) {
116 String8 result(kDeadlockedString);
117 if (fd >= 0) {
118 write(fd, result.string(), result.size());
119 } else {
120 ALOGW("%s:", result.string());
121 }
122 // TODO should we instead proceed to mMergeReader.dump? does it need lock?
123 return NO_ERROR;
124 }
125
126 for (const auto& namedReader : mNamedReaders) {
127 if (fd >= 0) {
128 dprintf(fd, "\n%s:\n", namedReader.name());
129 } else {
130 ALOGI("%s:", namedReader.name());
131 }
132 }
133 mLock.unlock();
134 }
135 }
136 mMergeReader.dump(fd);
137 return NO_ERROR;
138 }
139
onTransact(uint32_t code,const Parcel & data,Parcel * reply,uint32_t flags)140 status_t MediaLogService::onTransact(uint32_t code, const Parcel& data, Parcel* reply,
141 uint32_t flags)
142 {
143 return BnMediaLogService::onTransact(code, data, reply, flags);
144 }
145
requestMergeWakeup()146 void MediaLogService::requestMergeWakeup() {
147 mMergeThread->wakeup();
148 }
149
150 } // namespace android
151