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1 /*
2  * Copyright (C) 2012-2013 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 #pragma once
18 
19 #include <pthread.h>
20 #include <sys/socket.h>
21 #include <sys/types.h>
22 #include <time.h>
23 
24 #include <chrono>
25 #include <condition_variable>
26 #include <list>
27 #include <memory>
28 
29 #include <android-base/thread_annotations.h>
30 #include <log/log.h>
31 
32 #include "LogBuffer.h"
33 #include "LogWriter.h"
34 #include "LogdLock.h"
35 
36 class LogReaderList;
37 
38 class LogReaderThread {
39   public:
40     LogReaderThread(LogBuffer* log_buffer, LogReaderList* reader_list,
41                     std::unique_ptr<LogWriter> writer, bool non_block, unsigned long tail,
42                     LogMask log_mask, pid_t pid, log_time start_time, uint64_t sequence,
43                     std::chrono::steady_clock::time_point deadline);
TriggerReader()44     void TriggerReader() REQUIRES(logd_lock) { thread_triggered_condition_.notify_all(); }
45 
TriggerSkip(log_id_t id,unsigned int skip)46     void TriggerSkip(log_id_t id, unsigned int skip) REQUIRES(logd_lock) { skip_ahead_[id] = skip; }
CleanSkip()47     void CleanSkip() REQUIRES(logd_lock) { memset(skip_ahead_, 0, sizeof(skip_ahead_)); }
48 
Release()49     void Release() REQUIRES(logd_lock) {
50         // gracefully shut down the socket.
51         writer_->Shutdown();
52         release_ = true;
53         thread_triggered_condition_.notify_all();
54     }
55 
IsWatching(log_id_t id)56     bool IsWatching(log_id_t id) const REQUIRES(logd_lock) {
57         return flush_to_state_->log_mask() & (1 << id);
58     }
IsWatchingMultiple(LogMask log_mask)59     bool IsWatchingMultiple(LogMask log_mask) const REQUIRES(logd_lock) {
60         return flush_to_state_->log_mask() & log_mask;
61     }
62 
name()63     std::string name() const REQUIRES(logd_lock) { return writer_->name(); }
start()64     uint64_t start() const REQUIRES(logd_lock) { return flush_to_state_->start(); }
deadline()65     std::chrono::steady_clock::time_point deadline() const REQUIRES(logd_lock) { return deadline_; }
flush_to_state()66     FlushToState& flush_to_state() REQUIRES(logd_lock) { return *flush_to_state_; }
67 
68   private:
69     void ThreadFunction();
70     // flushTo filter callbacks
71     FilterResult FilterFirstPass(log_id_t log_id, pid_t pid, uint64_t sequence, log_time realtime)
72             REQUIRES(logd_lock);
73     FilterResult FilterSecondPass(log_id_t log_id, pid_t pid, uint64_t sequence, log_time realtime)
74             REQUIRES(logd_lock);
75 
76     std::condition_variable thread_triggered_condition_;
77     LogBuffer* log_buffer_;
78     LogReaderList* reader_list_;
79     std::unique_ptr<LogWriter> writer_ GUARDED_BY(logd_lock);
80 
81     // Set to true to cause the thread to end and the LogReaderThread to delete itself.
82     bool release_ GUARDED_BY(logd_lock) = false;
83 
84     // If set to non-zero, only pids equal to this are read by the reader.
85     const pid_t pid_;
86     // When a reader is referencing (via start_) old elements in the log buffer, and the log
87     // buffer's size grows past its memory limit, the log buffer may request the reader to skip
88     // ahead a specified number of logs.
89     unsigned int skip_ahead_[LOG_ID_MAX] GUARDED_BY(logd_lock);
90     // LogBuffer::FlushTo() needs to store state across subsequent calls.
91     std::unique_ptr<FlushToState> flush_to_state_ GUARDED_BY(logd_lock);
92 
93     // These next three variables are used for reading only the most recent lines aka `adb logcat
94     // -t` / `adb logcat -T`.
95     // tail_ is the number of most recent lines to print.
96     unsigned long tail_;
97     // count_ is the result of a first pass through the log buffer to determine how many total
98     // messages there are.
99     unsigned long count_;
100     // index_ is used along with count_ to only start sending lines once index_ > (count_ - tail_)
101     // and to disconnect the reader (if it is dumpAndClose, `adb logcat -t`), when index_ >= count_.
102     unsigned long index_;
103 
104     // When a reader requests logs starting from a given timestamp, its stored here for the first
105     // pass, such that logs before this time stamp that are accumulated in the buffer are ignored.
106     log_time start_time_;
107     // CLOCK_MONOTONIC based deadline used for log wrapping.  If this deadline expires before logs
108     // wrap, then wake up and send the logs to the reader anyway.
109     std::chrono::steady_clock::time_point deadline_ GUARDED_BY(logd_lock);
110     // If this reader is 'dumpAndClose' and will disconnect once it has read its intended logs.
111     const bool non_block_;
112 };
113