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      1 /*
      2  * Copyright (C) 2012-2014 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 <stdlib.h>
     18 
     19 #include <private/android_filesystem_config.h>
     20 
     21 #include "FlushCommand.h"
     22 #include "LogBuffer.h"
     23 #include "LogBufferElement.h"
     24 #include "LogCommand.h"
     25 #include "LogReader.h"
     26 #include "LogTimes.h"
     27 #include "LogUtils.h"
     28 
     29 // runSocketCommand is called once for every open client on the
     30 // log reader socket. Here we manage and associated the reader
     31 // client tracking and log region locks LastLogTimes list of
     32 // LogTimeEntrys, and spawn a transitory per-client thread to
     33 // work at filing data to the  socket.
     34 //
     35 // global LogTimeEntry::wrlock() is used to protect access,
     36 // reference counts are used to ensure that individual
     37 // LogTimeEntry lifetime is managed when not protected.
     38 void FlushCommand::runSocketCommand(SocketClient* client) {
     39     LogTimeEntry* entry = NULL;
     40     LastLogTimes& times = mReader.logbuf().mTimes;
     41 
     42     LogTimeEntry::wrlock();
     43     LastLogTimes::iterator it = times.begin();
     44     while (it != times.end()) {
     45         entry = (*it);
     46         if (entry->mClient == client) {
     47             if (!entry->isWatchingMultiple(mLogMask)) {
     48                 LogTimeEntry::unlock();
     49                 return;
     50             }
     51             if (entry->mTimeout.tv_sec || entry->mTimeout.tv_nsec) {
     52                 if (mReader.logbuf().isMonotonic()) {
     53                     LogTimeEntry::unlock();
     54                     return;
     55                 }
     56                 // If the user changes the time in a gross manner that
     57                 // invalidates the timeout, fall through and trigger.
     58                 log_time now(CLOCK_REALTIME);
     59                 if (((entry->mEnd + entry->mTimeout) > now) &&
     60                     (now > entry->mEnd)) {
     61                     LogTimeEntry::unlock();
     62                     return;
     63                 }
     64             }
     65             entry->triggerReader_Locked();
     66             if (entry->runningReader_Locked()) {
     67                 LogTimeEntry::unlock();
     68                 return;
     69             }
     70             entry->incRef_Locked();
     71             break;
     72         }
     73         it++;
     74     }
     75 
     76     if (it == times.end()) {
     77         // Create LogTimeEntry in notifyNewLog() ?
     78         if (mTail == (unsigned long)-1) {
     79             LogTimeEntry::unlock();
     80             return;
     81         }
     82         entry = new LogTimeEntry(mReader, client, mNonBlock, mTail, mLogMask,
     83                                  mPid, mStart, mTimeout);
     84         times.push_front(entry);
     85     }
     86 
     87     client->incRef();
     88 
     89     // release client and entry reference counts once done
     90     entry->startReader_Locked();
     91     LogTimeEntry::unlock();
     92 }
     93 
     94 bool FlushCommand::hasReadLogs(SocketClient* client) {
     95     return clientHasLogCredentials(client);
     96 }
     97 
     98 static bool clientHasSecurityCredentials(SocketClient* client) {
     99     return (client->getUid() == AID_SYSTEM) || (client->getGid() == AID_SYSTEM);
    100 }
    101 
    102 bool FlushCommand::hasSecurityLogs(SocketClient* client) {
    103     return clientHasSecurityCredentials(client);
    104 }
    105