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      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/nbaio/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 void MediaLogService::registerWriter(const sp<IMemory>& shared, size_t size, const char *name)
     32 {
     33     if (IPCThreadState::self()->getCallingUid() != AID_AUDIOSERVER || shared == 0 ||
     34             size < kMinSize || size > kMaxSize || name == NULL ||
     35             shared->size() < NBLog::Timeline::sharedSize(size)) {
     36         return;
     37     }
     38     sp<NBLog::Reader> reader(new NBLog::Reader(size, shared));
     39     NamedReader namedReader(reader, name);
     40     Mutex::Autolock _l(mLock);
     41     mNamedReaders.add(namedReader);
     42 }
     43 
     44 void MediaLogService::unregisterWriter(const sp<IMemory>& shared)
     45 {
     46     if (IPCThreadState::self()->getCallingUid() != AID_AUDIOSERVER || shared == 0) {
     47         return;
     48     }
     49     Mutex::Autolock _l(mLock);
     50     for (size_t i = 0; i < mNamedReaders.size(); ) {
     51         if (mNamedReaders[i].reader()->isIMemory(shared)) {
     52             mNamedReaders.removeAt(i);
     53         } else {
     54             i++;
     55         }
     56     }
     57 }
     58 
     59 bool MediaLogService::dumpTryLock(Mutex& mutex)
     60 {
     61     bool locked = false;
     62     for (int i = 0; i < kDumpLockRetries; ++i) {
     63         if (mutex.tryLock() == NO_ERROR) {
     64             locked = true;
     65             break;
     66         }
     67         usleep(kDumpLockSleepUs);
     68     }
     69     return locked;
     70 }
     71 
     72 status_t MediaLogService::dump(int fd, const Vector<String16>& args __unused)
     73 {
     74     // FIXME merge with similar but not identical code at services/audioflinger/ServiceUtilities.cpp
     75     static const String16 sDump("android.permission.DUMP");
     76     if (!(IPCThreadState::self()->getCallingUid() == AID_AUDIOSERVER ||
     77             PermissionCache::checkCallingPermission(sDump))) {
     78         dprintf(fd, "Permission Denial: can't dump media.log from pid=%d, uid=%d\n",
     79                 IPCThreadState::self()->getCallingPid(),
     80                 IPCThreadState::self()->getCallingUid());
     81         return NO_ERROR;
     82     }
     83 
     84     Vector<NamedReader> namedReaders;
     85     {
     86         bool locked = dumpTryLock(mLock);
     87 
     88         // failed to lock - MediaLogService is probably deadlocked
     89         if (!locked) {
     90             String8 result(kDeadlockedString);
     91             if (fd >= 0) {
     92                 write(fd, result.string(), result.size());
     93             } else {
     94                 ALOGW("%s:", result.string());
     95             }
     96             return NO_ERROR;
     97         }
     98         namedReaders = mNamedReaders;
     99         mLock.unlock();
    100     }
    101 
    102     for (size_t i = 0; i < namedReaders.size(); i++) {
    103         const NamedReader& namedReader = namedReaders[i];
    104         if (fd >= 0) {
    105             dprintf(fd, "\n%s:\n", namedReader.name());
    106         } else {
    107             ALOGI("%s:", namedReader.name());
    108         }
    109         namedReader.reader()->dump(fd, 0 /*indent*/);
    110     }
    111     return NO_ERROR;
    112 }
    113 
    114 status_t MediaLogService::onTransact(uint32_t code, const Parcel& data, Parcel* reply,
    115         uint32_t flags)
    116 {
    117     return BnMediaLogService::onTransact(code, data, reply, flags);
    118 }
    119 
    120 }   // namespace android
    121