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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 struct PendingReaderThreadKey {
37     uid_t uid;
38     gid_t gid;
39     pid_t pid;
40     int32_t fd;
41     bool operator==(const PendingReaderThreadKey& rhs) const {
42         return uid == rhs.uid && gid == rhs.gid && pid == rhs.pid && fd == rhs.fd;
43     }
44 };
45 
46 class LogReaderList;
47 
48 class LogReaderThread {
49   public:
50     LogReaderThread(LogBuffer* log_buffer, LogReaderList* reader_list,
51                     std::unique_ptr<LogWriter> writer, bool non_block, unsigned long tail,
52                     LogMask log_mask, pid_t pid, log_time start_time, uint64_t sequence,
53                     std::chrono::steady_clock::time_point deadline);
TriggerReader()54     void TriggerReader() REQUIRES(logd_lock) { thread_triggered_condition_.notify_all(); }
55 
TriggerSkip(log_id_t id,unsigned int skip)56     void TriggerSkip(log_id_t id, unsigned int skip) REQUIRES(logd_lock) { skip_ahead_[id] = skip; }
CleanSkip()57     void CleanSkip() REQUIRES(logd_lock) { memset(skip_ahead_, 0, sizeof(skip_ahead_)); }
58 
59     void Run() REQUIRES(logd_lock);
Revoke()60     void Revoke() REQUIRES(logd_lock) { writer_->revoke(); }
Release()61     void Release() REQUIRES(logd_lock) {
62         // gracefully shut down the socket.
63         writer_->Shutdown();
64         release_ = true;
65         thread_triggered_condition_.notify_all();
66     }
67 
IsWatching(log_id_t id)68     bool IsWatching(log_id_t id) const REQUIRES(logd_lock) {
69         return flush_to_state_->log_mask() & (1 << id);
70     }
IsWatchingMultiple(LogMask log_mask)71     bool IsWatchingMultiple(LogMask log_mask) const REQUIRES(logd_lock) {
72         return flush_to_state_->log_mask() & log_mask;
73     }
74 
name()75     std::string name() const REQUIRES(logd_lock) { return writer_->name(); }
start()76     uint64_t start() const REQUIRES(logd_lock) { return flush_to_state_->start(); }
deadline()77     std::chrono::steady_clock::time_point deadline() const REQUIRES(logd_lock) { return deadline_; }
flush_to_state()78     FlushToState& flush_to_state() REQUIRES(logd_lock) { return *flush_to_state_; }
set_pending_reader_thread_key(uid_t uid,gid_t gid,pid_t pid,int32_t fd)79     void set_pending_reader_thread_key(uid_t uid, gid_t gid, pid_t pid, int32_t fd)
80             REQUIRES(logd_lock) {
81         pending_reader_thread_key_ = {uid, gid, pid, fd};
82     }
pending_reader_thread_key()83     const PendingReaderThreadKey& pending_reader_thread_key() const REQUIRES(logd_lock) {
84         return pending_reader_thread_key_;
85     }
set_finish_flag()86     void set_finish_flag() REQUIRES(logd_lock) { finished_ = true; }
finish_flag()87     bool finish_flag() REQUIRES(logd_lock) { return finished_; }
set_track_flag()88     void set_track_flag() REQUIRES(logd_lock) { tracked_ = true; }
track_flag()89     bool track_flag() REQUIRES(logd_lock) { return tracked_; }
90 
91   private:
92     void ThreadFunction();
93     // flushTo filter callbacks
94     FilterResult FilterFirstPass(log_id_t log_id, pid_t pid, uint64_t sequence, log_time realtime)
95             REQUIRES(logd_lock);
96     FilterResult FilterSecondPass(log_id_t log_id, pid_t pid, uint64_t sequence, log_time realtime)
97             REQUIRES(logd_lock);
98 
99     std::condition_variable thread_triggered_condition_;
100     LogBuffer* log_buffer_;
101     LogReaderList* reader_list_;
102     std::unique_ptr<LogWriter> writer_ GUARDED_BY(logd_lock);
103 
104     PendingReaderThreadKey pending_reader_thread_key_ GUARDED_BY(logd_lock);
105     // Set to true to indicate the thread has finished.
106     bool finished_ GUARDED_BY(logd_lock) = false;
107     // Set to true to indicate the thread is tracked by AppOps.
108     bool tracked_ GUARDED_BY(logd_lock) = false;
109 
110     // Set to true to cause the thread to end and the LogReaderThread to delete itself.
111     bool release_ GUARDED_BY(logd_lock) = false;
112 
113     // If set to non-zero, only pids equal to this are read by the reader.
114     const pid_t pid_;
115     // When a reader is referencing (via start_) old elements in the log buffer, and the log
116     // buffer's size grows past its memory limit, the log buffer may request the reader to skip
117     // ahead a specified number of logs.
118     unsigned int skip_ahead_[LOG_ID_MAX] GUARDED_BY(logd_lock);
119     // LogBuffer::FlushTo() needs to store state across subsequent calls.
120     std::unique_ptr<FlushToState> flush_to_state_ GUARDED_BY(logd_lock);
121 
122     // These next three variables are used for reading only the most recent lines aka `adb logcat
123     // -t` / `adb logcat -T`.
124     // tail_ is the number of most recent lines to print.
125     unsigned long tail_;
126     // count_ is the result of a first pass through the log buffer to determine how many total
127     // messages there are.
128     unsigned long count_;
129     // index_ is used along with count_ to only start sending lines once index_ > (count_ - tail_)
130     // and to disconnect the reader (if it is dumpAndClose, `adb logcat -t`), when index_ >= count_.
131     unsigned long index_;
132 
133     // When a reader requests logs starting from a given timestamp, its stored here for the first
134     // pass, such that logs before this time stamp that are accumulated in the buffer are ignored.
135     log_time start_time_;
136     // CLOCK_MONOTONIC based deadline used for log wrapping.  If this deadline expires before logs
137     // wrap, then wake up and send the logs to the reader anyway.
138     std::chrono::steady_clock::time_point deadline_ GUARDED_BY(logd_lock);
139     // If this reader is 'dumpAndClose' and will disconnect once it has read its intended logs.
140     const bool non_block_;
141 };
142