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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.
runSocketCommand(SocketClient * client)38 void FlushCommand::runSocketCommand(SocketClient* client) {
39     LogTimeEntry* entry = nullptr;
40     LastLogTimes& times = mReader.logbuf().mTimes;
41 
42     LogTimeEntry::wrlock();
43     LastLogTimes::iterator it = times.begin();
44     while (it != times.end()) {
45         entry = it->get();
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             LogTimeEntry::unlock();
67             return;
68         }
69         it++;
70     }
71 
72     LogTimeEntry::unlock();
73 }
74 
hasReadLogs(SocketClient * client)75 bool FlushCommand::hasReadLogs(SocketClient* client) {
76     return clientHasLogCredentials(client);
77 }
78 
clientHasSecurityCredentials(SocketClient * client)79 static bool clientHasSecurityCredentials(SocketClient* client) {
80     return (client->getUid() == AID_SYSTEM) || (client->getGid() == AID_SYSTEM);
81 }
82 
hasSecurityLogs(SocketClient * client)83 bool FlushCommand::hasSecurityLogs(SocketClient* client) {
84     return clientHasSecurityCredentials(client);
85 }
86