LogBuffer.h revision 61e9ce6709a12cf39a9471476da3d50339efe466 
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 "LogTags.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 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,
90                               LogBufferElementCollection::iterator>
91                LogBufferIteratorMap;
92    LogBufferIteratorMap mLastWorst[LOG_ID_MAX];
93    // watermark of any worst/chatty pid of system processing
94    typedef std::unordered_map<pid_t,
95                               LogBufferElementCollection::iterator>
96                LogBufferPidIteratorMap;
97    LogBufferPidIteratorMap mLastWorstPidOfSystem[LOG_ID_MAX];
98
99    unsigned long mMaxSize[LOG_ID_MAX];
100
101    bool monotonic;
102
103    LogTags tags;
104
105    LogBufferElement* lastLoggedElements[LOG_ID_MAX];
106    LogBufferElement* droppedElements[LOG_ID_MAX];
107    void log(LogBufferElement* elem);
108
109public:
110    LastLogTimes &mTimes;
111
112    explicit LogBuffer(LastLogTimes *times);
113    ~LogBuffer();
114    void init();
115    bool isMonotonic() { return monotonic; }
116
117    int log(log_id_t log_id, log_time realtime,
118            uid_t uid, pid_t pid, pid_t tid,
119            const char *msg, unsigned short len);
120    uint64_t flushTo(SocketClient *writer, const uint64_t start,
121                     bool privileged, bool security,
122                     int (*filter)(const LogBufferElement *element, void *arg) = NULL,
123                     void *arg = NULL);
124
125    bool clear(log_id_t id, uid_t uid = AID_ROOT);
126    unsigned long getSize(log_id_t id);
127    int setSize(log_id_t id, unsigned long size);
128    unsigned long getSizeUsed(log_id_t id);
129
130    std::string formatStatistics(uid_t uid, pid_t pid, unsigned int logMask);
131
132    void enableStatistics() {
133        stats.enableStatistics();
134    }
135
136    int initPrune(const char *cp) { return mPrune.init(cp); }
137    std::string formatPrune() { return mPrune.format(); }
138
139    std::string formatGetEventTag(uid_t uid,
140                                  const char *name, const char *format) {
141        return tags.formatGetEventTag(uid, name, format);
142    }
143    const char *tagToName(uint32_t tag) { return tags.tagToName(tag); }
144
145    // helper must be protected directly or implicitly by lock()/unlock()
146    const char *pidToName(pid_t pid) { return stats.pidToName(pid); }
147    uid_t pidToUid(pid_t pid) { return stats.pidToUid(pid); }
148    const char *uidToName(uid_t uid) { return stats.uidToName(uid); }
149    void lock() { pthread_mutex_lock(&mLogElementsLock); }
150    void unlock() { pthread_mutex_unlock(&mLogElementsLock); }
151
152private:
153
154    static constexpr size_t minPrune = 4;
155    static constexpr size_t maxPrune = 256;
156
157    void maybePrune(log_id_t id);
158    bool prune(log_id_t id, unsigned long pruneRows, uid_t uid = AID_ROOT);
159    LogBufferElementCollection::iterator erase(
160        LogBufferElementCollection::iterator it, bool coalesce = false);
161};
162
163#endif // _LOGD_LOG_BUFFER_H__
164