LogBuffer.h revision 10b82b683405e9ccd0cc162fa44a2ec6a9f26448 
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 <log/log.h>
26#include <sysutils/SocketClient.h>
27
28#include <private/android_filesystem_config.h>
29
30#include "LogBufferElement.h"
31#include "LogTimes.h"
32#include "LogStatistics.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}
75
76typedef std::list<LogBufferElement *> LogBufferElementCollection;
77
78class LogBuffer {
79    LogBufferElementCollection mLogElements;
80    pthread_mutex_t mLogElementsLock;
81
82    LogStatistics stats;
83
84    PruneList mPrune;
85    // watermark of any worst/chatty uid processing
86    typedef std::unordered_map<uid_t,
87                               LogBufferElementCollection::iterator>
88                LogBufferIteratorMap;
89    LogBufferIteratorMap mLastWorstUid[LOG_ID_MAX];
90    // watermark of any worst/chatty pid of system processing
91    typedef std::unordered_map<pid_t,
92                               LogBufferElementCollection::iterator>
93                LogBufferPidIteratorMap;
94    LogBufferPidIteratorMap mLastWorstPidOfSystem[LOG_ID_MAX];
95
96    unsigned long mMaxSize[LOG_ID_MAX];
97
98    bool monotonic;
99
100public:
101    LastLogTimes &mTimes;
102
103    LogBuffer(LastLogTimes *times);
104    void init();
105    bool isMonotonic() { return monotonic; }
106
107    int log(log_id_t log_id, log_time realtime,
108            uid_t uid, pid_t pid, pid_t tid,
109            const char *msg, unsigned short len);
110    uint64_t flushTo(SocketClient *writer, const uint64_t start,
111                     bool privileged,
112                     int (*filter)(const LogBufferElement *element, void *arg) = NULL,
113                     void *arg = NULL);
114
115    bool clear(log_id_t id, uid_t uid = AID_ROOT);
116    unsigned long getSize(log_id_t id);
117    int setSize(log_id_t id, unsigned long size);
118    unsigned long getSizeUsed(log_id_t id);
119    // *strp uses malloc, use free to release.
120    std::string formatStatistics(uid_t uid, pid_t pid, unsigned int logMask);
121
122    void enableStatistics() {
123        stats.enableStatistics();
124    }
125
126    int initPrune(const char *cp) { return mPrune.init(cp); }
127    std::string formatPrune() { return mPrune.format(); }
128
129    // helper must be protected directly or implicitly by lock()/unlock()
130    const char *pidToName(pid_t pid) { return stats.pidToName(pid); }
131    uid_t pidToUid(pid_t pid) { return stats.pidToUid(pid); }
132    const char *uidToName(uid_t uid) { return stats.uidToName(uid); }
133    void lock() { pthread_mutex_lock(&mLogElementsLock); }
134    void unlock() { pthread_mutex_unlock(&mLogElementsLock); }
135
136private:
137
138    static constexpr size_t minPrune = 4;
139    static constexpr size_t maxPrune = 256;
140
141    void maybePrune(log_id_t id);
142    bool prune(log_id_t id, unsigned long pruneRows, uid_t uid = AID_ROOT);
143    LogBufferElementCollection::iterator erase(
144        LogBufferElementCollection::iterator it, bool coalesce = false);
145};
146
147#endif // _LOGD_LOG_BUFFER_H__
148