LogBuffer.h revision fafea32468e0d59c1ce2eb845dd07a0b4e746cf0 
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#ifndef _LOGD_LOG_BUFFER_H__
18#define _LOGD_LOG_BUFFER_H__
19
20#include <sys/types.h>
21
22#include <list>
23#include <string>
24
25#include <android/log.h>
26#include <private/android_filesystem_config.h>
27#include <sysutils/SocketClient.h>
28
29#include "LogBufferElement.h"
30#include "LogBufferInterface.h"
31#include "LogStatistics.h"
32#include "LogTags.h"
33#include "LogTimes.h"
34#include "LogWhiteBlackList.h"
35
36//
37// We are either in 1970ish (MONOTONIC) or 2016+ish (REALTIME) so to
38// differentiate without prejudice, we use 1972 to delineate, earlier
39// is likely monotonic, later is real. Otherwise we start using a
40// dividing line between monotonic and realtime if more than a minute
41// difference between them.
42//
43namespace android {
44
45static bool isMonotonic(const log_time& mono) {
46    static const uint32_t EPOCH_PLUS_2_YEARS = 2 * 24 * 60 * 60 * 1461 / 4;
47    static const uint32_t EPOCH_PLUS_MINUTE = 60;
48
49    if (mono.tv_sec >= EPOCH_PLUS_2_YEARS) {
50        return false;
51    }
52
53    log_time now(CLOCK_REALTIME);
54
55    /* Timezone and ntp time setup? */
56    if (now.tv_sec >= EPOCH_PLUS_2_YEARS) {
57        return true;
58    }
59
60    /* no way to differentiate realtime from monotonic time */
61    if (now.tv_sec < EPOCH_PLUS_MINUTE) {
62        return false;
63    }
64
65    log_time cpu(CLOCK_MONOTONIC);
66    /* too close to call to differentiate monotonic times from realtime */
67    if ((cpu.tv_sec + EPOCH_PLUS_MINUTE) >= now.tv_sec) {
68        return false;
69    }
70
71    /* dividing line half way between monotonic and realtime */
72    return mono.tv_sec < ((cpu.tv_sec + now.tv_sec) / 2);
73}
74}
75
76typedef std::list<LogBufferElement*> LogBufferElementCollection;
77
78class LogBuffer : public LogBufferInterface {
79    LogBufferElementCollection mLogElements;
80    pthread_rwlock_t mLogElementsLock;
81
82    LogStatistics stats;
83
84    PruneList mPrune;
85    // watermark for last per log id
86    LogBufferElementCollection::iterator mLast[LOG_ID_MAX];
87    bool mLastSet[LOG_ID_MAX];
88    // watermark of any worst/chatty uid processing
89    typedef std::unordered_map<uid_t, LogBufferElementCollection::iterator>
90        LogBufferIteratorMap;
91    LogBufferIteratorMap mLastWorst[LOG_ID_MAX];
92    // watermark of any worst/chatty pid of system processing
93    typedef std::unordered_map<pid_t, LogBufferElementCollection::iterator>
94        LogBufferPidIteratorMap;
95    LogBufferPidIteratorMap mLastWorstPidOfSystem[LOG_ID_MAX];
96
97    unsigned long mMaxSize[LOG_ID_MAX];
98
99    bool monotonic;
100
101    LogTags tags;
102
103    LogBufferElement* lastLoggedElements[LOG_ID_MAX];
104    LogBufferElement* droppedElements[LOG_ID_MAX];
105    void log(LogBufferElement* elem);
106
107   public:
108    LastLogTimes& mTimes;
109
110    explicit LogBuffer(LastLogTimes* times);
111    ~LogBuffer() override;
112    void init();
113    bool isMonotonic() {
114        return monotonic;
115    }
116
117    int log(log_id_t log_id, log_time realtime, uid_t uid, pid_t pid, pid_t tid,
118            const char* msg, unsigned short len) override;
119    // lastTid is an optional context to help detect if the last previous
120    // valid message was from the same source so we can differentiate chatty
121    // filter types (identical or expired)
122    log_time flushTo(SocketClient* writer, const log_time& start,
123                     pid_t* lastTid,  // &lastTid[LOG_ID_MAX] or nullptr
124                     bool privileged, bool security,
125                     int (*filter)(const LogBufferElement* element,
126                                   void* arg) = nullptr,
127                     void* arg = nullptr);
128
129    bool clear(log_id_t id, uid_t uid = AID_ROOT);
130    unsigned long getSize(log_id_t id);
131    int setSize(log_id_t id, unsigned long size);
132    unsigned long getSizeUsed(log_id_t id);
133
134    std::string formatStatistics(uid_t uid, pid_t pid, unsigned int logMask);
135
136    void enableStatistics() {
137        stats.enableStatistics();
138    }
139
140    int initPrune(const char* cp) {
141        return mPrune.init(cp);
142    }
143    std::string formatPrune() {
144        return mPrune.format();
145    }
146
147    std::string formatGetEventTag(uid_t uid, const char* name,
148                                  const char* format) {
149        return tags.formatGetEventTag(uid, name, format);
150    }
151    std::string formatEntry(uint32_t tag, uid_t uid) {
152        return tags.formatEntry(tag, uid);
153    }
154    const char* tagToName(uint32_t tag) {
155        return tags.tagToName(tag);
156    }
157
158    // helper must be protected directly or implicitly by wrlock()/unlock()
159    const char* pidToName(pid_t pid) {
160        return stats.pidToName(pid);
161    }
162    uid_t pidToUid(pid_t pid) {
163        return stats.pidToUid(pid);
164    }
165    const char* uidToName(uid_t uid) {
166        return stats.uidToName(uid);
167    }
168    void wrlock() {
169        pthread_rwlock_wrlock(&mLogElementsLock);
170    }
171    void rdlock() {
172        pthread_rwlock_rdlock(&mLogElementsLock);
173    }
174    void unlock() {
175        pthread_rwlock_unlock(&mLogElementsLock);
176    }
177
178   private:
179    static constexpr size_t minPrune = 4;
180    static constexpr size_t maxPrune = 256;
181    static const log_time pruneMargin;
182
183    void maybePrune(log_id_t id);
184    bool prune(log_id_t id, unsigned long pruneRows, uid_t uid = AID_ROOT);
185    LogBufferElementCollection::iterator erase(
186        LogBufferElementCollection::iterator it, bool coalesce = false);
187};
188
189#endif  // _LOGD_LOG_BUFFER_H__
190