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      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 //
     42 namespace android {
     43 
     44 static 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 
     76 typedef std::list<LogBufferElement *> LogBufferElementCollection;
     77 
     78 class 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 mLastWorstUid[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 public:
    104     LastLogTimes &mTimes;
    105 
    106     LogBuffer(LastLogTimes *times);
    107     void init();
    108     bool isMonotonic() { return monotonic; }
    109 
    110     int log(log_id_t log_id, log_time realtime,
    111             uid_t uid, pid_t pid, pid_t tid,
    112             const char *msg, unsigned short len);
    113     uint64_t flushTo(SocketClient *writer, const uint64_t start,
    114                      bool privileged, bool security,
    115                      int (*filter)(const LogBufferElement *element, void *arg) = NULL,
    116                      void *arg = NULL);
    117 
    118     bool clear(log_id_t id, uid_t uid = AID_ROOT);
    119     unsigned long getSize(log_id_t id);
    120     int setSize(log_id_t id, unsigned long size);
    121     unsigned long getSizeUsed(log_id_t id);
    122     // *strp uses malloc, use free to release.
    123     std::string formatStatistics(uid_t uid, pid_t pid, unsigned int logMask);
    124 
    125     void enableStatistics() {
    126         stats.enableStatistics();
    127     }
    128 
    129     int initPrune(const char *cp) { return mPrune.init(cp); }
    130     std::string formatPrune() { return mPrune.format(); }
    131 
    132     // helper must be protected directly or implicitly by lock()/unlock()
    133     const char *pidToName(pid_t pid) { return stats.pidToName(pid); }
    134     uid_t pidToUid(pid_t pid) { return stats.pidToUid(pid); }
    135     const char *uidToName(uid_t uid) { return stats.uidToName(uid); }
    136     void lock() { pthread_mutex_lock(&mLogElementsLock); }
    137     void unlock() { pthread_mutex_unlock(&mLogElementsLock); }
    138 
    139 private:
    140 
    141     static constexpr size_t minPrune = 4;
    142     static constexpr size_t maxPrune = 256;
    143 
    144     void maybePrune(log_id_t id);
    145     bool prune(log_id_t id, unsigned long pruneRows, uid_t uid = AID_ROOT);
    146     LogBufferElementCollection::iterator erase(
    147         LogBufferElementCollection::iterator it, bool coalesce = false);
    148 };
    149 
    150 #endif // _LOGD_LOG_BUFFER_H__
    151