FlushCommand.cpp revision c03e72cc1c155ff668df8df1caec363b07347d0d 
1/*
2 * Copyright (C) 2012-2013 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#include <stdlib.h>
18#include <private/android_filesystem_config.h>
19#include "FlushCommand.h"
20#include "LogBufferElement.h"
21#include "LogTimes.h"
22#include "LogReader.h"
23
24FlushCommand::FlushCommand(LogReader &reader,
25                           bool nonBlock,
26                           unsigned long tail,
27                           unsigned int logMask,
28                           pid_t pid)
29        : mReader(reader)
30        , mNonBlock(nonBlock)
31        , mTail(tail)
32        , mLogMask(logMask)
33        , mPid(pid)
34{ }
35
36// runSocketCommand is called once for every open client on the
37// log reader socket. Here we manage and associated the reader
38// client tracking and log region locks LastLogTimes list of
39// LogTimeEntrys, and spawn a transitory per-client thread to
40// work at filing data to the  socket.
41//
42// global LogTimeEntry::lock() is used to protect access,
43// reference counts are used to ensure that individual
44// LogTimeEntry lifetime is managed when not protected.
45void FlushCommand::runSocketCommand(SocketClient *client) {
46    LogTimeEntry *entry = NULL;
47    LastLogTimes &times = mReader.logbuf().mTimes;
48
49    LogTimeEntry::lock();
50    LastLogTimes::iterator it = times.begin();
51    while(it != times.end()) {
52        entry = (*it);
53        if (entry->mClient == client) {
54            entry->triggerReader_Locked();
55            if (entry->runningReader_Locked()) {
56                LogTimeEntry::unlock();
57                return;
58            }
59            entry->incRef_Locked();
60            break;
61        }
62        it++;
63    }
64
65    if (it == times.end()) {
66        // Create LogTimeEntry in notifyNewLog() ?
67        if (mTail == (unsigned long) -1) {
68            LogTimeEntry::unlock();
69            return;
70        }
71        entry = new LogTimeEntry(mReader, client, mNonBlock, mTail, mLogMask, mPid);
72        times.push_back(entry);
73    }
74
75    client->incRef();
76
77    // release client and entry reference counts once done
78    entry->startReader_Locked();
79    LogTimeEntry::unlock();
80}
81
82bool FlushCommand::hasReadLogs(SocketClient *client) {
83    return (client->getUid() == AID_ROOT)
84            || (client->getGid() == AID_ROOT)
85            || (client->getGid() == AID_LOG);
86}
87