LogBuffer.h revision ae2abf112ca8555dfc09eb1fc4b8bd637e4bc7cc 
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 "LogStatistics.h"
31#include "LogTags.h"
32#include "LogTimes.h"
33#include "LogWhiteBlackList.h"
34
35//
36// We are either in 1970ish (MONOTONIC) or 2016+ish (REALTIME) so to
37// differentiate without prejudice, we use 1972 to delineate, earlier
38// is likely monotonic, later is real. Otherwise we start using a
39// dividing line between monotonic and realtime if more than a minute
40// difference between them.
41//
42namespace android {
43
44static bool isMonotonic(const log_time& mono) {
45    static const uint32_t EPOCH_PLUS_2_YEARS = 2 * 24 * 60 * 60 * 1461 / 4;
46    static const uint32_t EPOCH_PLUS_MINUTE = 60;
47
48    if (mono.tv_sec >= EPOCH_PLUS_2_YEARS) {
49        return false;
50    }
51
52    log_time now(CLOCK_REALTIME);
53
54    /* Timezone and ntp time setup? */
55    if (now.tv_sec >= EPOCH_PLUS_2_YEARS) {
56        return true;
57    }
58
59    /* no way to differentiate realtime from monotonic time */
60    if (now.tv_sec < EPOCH_PLUS_MINUTE) {
61        return false;
62    }
63
64    log_time cpu(CLOCK_MONOTONIC);
65    /* too close to call to differentiate monotonic times from realtime */
66    if ((cpu.tv_sec + EPOCH_PLUS_MINUTE) >= now.tv_sec) {
67        return false;
68    }
69
70    /* dividing line half way between monotonic and realtime */
71    return mono.tv_sec < ((cpu.tv_sec + now.tv_sec) / 2);
72}
73}
74
75typedef std::list<LogBufferElement*> LogBufferElementCollection;
76
77class LogBuffer {
78    LogBufferElementCollection mLogElements;
79    pthread_mutex_t mLogElementsLock;
80
81    LogStatistics stats;
82
83    PruneList mPrune;
84    // watermark for last per log id
85    LogBufferElementCollection::iterator mLast[LOG_ID_MAX];
86    bool mLastSet[LOG_ID_MAX];
87    // watermark of any worst/chatty uid processing
88    typedef std::unordered_map<uid_t, LogBufferElementCollection::iterator>
89        LogBufferIteratorMap;
90    LogBufferIteratorMap mLastWorst[LOG_ID_MAX];
91    // watermark of any worst/chatty pid of system processing
92    typedef std::unordered_map<pid_t, LogBufferElementCollection::iterator>
93        LogBufferPidIteratorMap;
94    LogBufferPidIteratorMap mLastWorstPidOfSystem[LOG_ID_MAX];
95
96    unsigned long mMaxSize[LOG_ID_MAX];
97
98    bool monotonic;
99
100    LogTags tags;
101
102    LogBufferElement* lastLoggedElements[LOG_ID_MAX];
103    LogBufferElement* droppedElements[LOG_ID_MAX];
104    void log(LogBufferElement* elem);
105
106   public:
107    LastLogTimes& mTimes;
108
109    explicit LogBuffer(LastLogTimes* times);
110    ~LogBuffer();
111    void init();
112    bool isMonotonic() {
113        return monotonic;
114    }
115
116    int log(log_id_t log_id, log_time realtime, uid_t uid, pid_t pid, pid_t tid,
117            const char* msg, unsigned short len);
118    // lastTid is an optional context to help detect if the last previous
119    // valid message was from the same source so we can differentiate chatty
120    // filter types (identical or expired)
121    log_time flushTo(SocketClient* writer, const log_time& start,
122                     pid_t* lastTid,  // &lastTid[LOG_ID_MAX] or nullptr
123                     bool privileged, bool security,
124                     int (*filter)(const LogBufferElement* element,
125                                   void* arg) = nullptr,
126                     void* arg = nullptr);
127
128    bool clear(log_id_t id, uid_t uid = AID_ROOT);
129    unsigned long getSize(log_id_t id);
130    int setSize(log_id_t id, unsigned long size);
131    unsigned long getSizeUsed(log_id_t id);
132
133    std::string formatStatistics(uid_t uid, pid_t pid, unsigned int logMask);
134
135    void enableStatistics() {
136        stats.enableStatistics();
137    }
138
139    int initPrune(const char* cp) {
140        return mPrune.init(cp);
141    }
142    std::string formatPrune() {
143        return mPrune.format();
144    }
145
146    std::string formatGetEventTag(uid_t uid, const char* name,
147                                  const char* format) {
148        return tags.formatGetEventTag(uid, name, format);
149    }
150    std::string formatEntry(uint32_t tag, uid_t uid) {
151        return tags.formatEntry(tag, uid);
152    }
153    const char* tagToName(uint32_t tag) {
154        return tags.tagToName(tag);
155    }
156
157    // helper must be protected directly or implicitly by lock()/unlock()
158    const char* pidToName(pid_t pid) {
159        return stats.pidToName(pid);
160    }
161    uid_t pidToUid(pid_t pid) {
162        return stats.pidToUid(pid);
163    }
164    const char* uidToName(uid_t uid) {
165        return stats.uidToName(uid);
166    }
167    void lock() {
168        pthread_mutex_lock(&mLogElementsLock);
169    }
170    void unlock() {
171        pthread_mutex_unlock(&mLogElementsLock);
172    }
173
174   private:
175    static constexpr size_t minPrune = 4;
176    static constexpr size_t maxPrune = 256;
177
178    void maybePrune(log_id_t id);
179    bool prune(log_id_t id, unsigned long pruneRows, uid_t uid = AID_ROOT);
180    LogBufferElementCollection::iterator erase(
181        LogBufferElementCollection::iterator it, bool coalesce = false);
182};
183
184#endif  // _LOGD_LOG_BUFFER_H__
185