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
FlushCommand(LogReader & reader,bool nonBlock,unsigned long tail,unsigned int logMask,pid_t pid,log_time start,uint64_t timeout)29 FlushCommand::FlushCommand(LogReader& reader, bool nonBlock, unsigned long tail,
30 unsigned int logMask, pid_t pid, log_time start,
31 uint64_t timeout)
32 : mReader(reader),
33 mNonBlock(nonBlock),
34 mTail(tail),
35 mLogMask(logMask),
36 mPid(pid),
37 mStart(start),
38 mTimeout((start != log_time::EPOCH) ? timeout : 0) {
39 }
40
41 // runSocketCommand is called once for every open client on the
42 // log reader socket. Here we manage and associated the reader
43 // client tracking and log region locks LastLogTimes list of
44 // LogTimeEntrys, and spawn a transitory per-client thread to
45 // work at filing data to the socket.
46 //
47 // global LogTimeEntry::wrlock() is used to protect access,
48 // reference counts are used to ensure that individual
49 // LogTimeEntry lifetime is managed when not protected.
runSocketCommand(SocketClient * client)50 void FlushCommand::runSocketCommand(SocketClient* client) {
51 LogTimeEntry* entry = NULL;
52 LastLogTimes& times = mReader.logbuf().mTimes;
53
54 LogTimeEntry::wrlock();
55 LastLogTimes::iterator it = times.begin();
56 while (it != times.end()) {
57 entry = (*it);
58 if (entry->mClient == client) {
59 if (entry->mTimeout.tv_sec || entry->mTimeout.tv_nsec) {
60 if (mReader.logbuf().isMonotonic()) {
61 LogTimeEntry::unlock();
62 return;
63 }
64 // If the user changes the time in a gross manner that
65 // invalidates the timeout, fall through and trigger.
66 log_time now(CLOCK_REALTIME);
67 if (((entry->mEnd + entry->mTimeout) > now) &&
68 (now > entry->mEnd)) {
69 LogTimeEntry::unlock();
70 return;
71 }
72 }
73 entry->triggerReader_Locked();
74 if (entry->runningReader_Locked()) {
75 LogTimeEntry::unlock();
76 return;
77 }
78 entry->incRef_Locked();
79 break;
80 }
81 it++;
82 }
83
84 if (it == times.end()) {
85 // Create LogTimeEntry in notifyNewLog() ?
86 if (mTail == (unsigned long)-1) {
87 LogTimeEntry::unlock();
88 return;
89 }
90 entry = new LogTimeEntry(mReader, client, mNonBlock, mTail, mLogMask,
91 mPid, mStart, mTimeout);
92 times.push_front(entry);
93 }
94
95 client->incRef();
96
97 // release client and entry reference counts once done
98 entry->startReader_Locked();
99 LogTimeEntry::unlock();
100 }
101
hasReadLogs(SocketClient * client)102 bool FlushCommand::hasReadLogs(SocketClient* client) {
103 return clientHasLogCredentials(client);
104 }
105
clientHasSecurityCredentials(SocketClient * client)106 static bool clientHasSecurityCredentials(SocketClient* client) {
107 return (client->getUid() == AID_SYSTEM) || (client->getGid() == AID_SYSTEM);
108 }
109
hasSecurityLogs(SocketClient * client)110 bool FlushCommand::hasSecurityLogs(SocketClient* client) {
111 return clientHasSecurityCredentials(client);
112 }
113