1// Copyright 2009 Google Inc. All Rights Reserved.
2
3// Licensed under the Apache License, Version 2.0 (the "License");
4// you may not use this file except in compliance with the License.
5// You may obtain a copy of the License at
6
7//      http://www.apache.org/licenses/LICENSE-2.0
8
9// Unless required by applicable law or agreed to in writing, software
10// distributed under the License is distributed on an "AS IS" BASIS,
11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12// See the License for the specific language governing permissions and
13// limitations under the License.
14
15#include "logger.h"
16
17#include <pthread.h>
18#include <stdarg.h>
19#include <stdio.h>
20#include <time.h>
21#include <unistd.h>
22
23#include <string>
24#include <vector>
25
26// This file must work with autoconf on its public version,
27// so these includes are correct.
28#include "sattypes.h"
29
30
31Logger *Logger::GlobalLogger() {
32  static Logger logger;
33  return &logger;
34}
35
36void Logger::VLogF(int priority, const char *format, va_list args) {
37  if (priority > verbosity_) {
38    return;
39  }
40  char buffer[4096];
41  size_t length = 0;
42  if (log_timestamps_) {
43    time_t raw_time;
44    time(&raw_time);
45    struct tm time_struct;
46    localtime_r(&raw_time, &time_struct);
47    length = strftime(buffer, sizeof(buffer), "%Y/%m/%d-%H:%M:%S(%Z) ",
48                      &time_struct);
49    LOGGER_ASSERT(length);  // Catch if the buffer is set too small.
50  }
51  length += vsnprintf(buffer + length, sizeof(buffer) - length, format, args);
52  if (length >= sizeof(buffer)) {
53    length = sizeof(buffer);
54    buffer[sizeof(buffer) - 1] = '\n';
55  }
56  QueueLogLine(new string(buffer, length));
57}
58
59void Logger::StartThread() {
60  LOGGER_ASSERT(!thread_running_);
61  thread_running_ = true;
62  LOGGER_ASSERT(0 == pthread_create(&thread_, NULL, &StartRoutine, this));
63}
64
65void Logger::StopThread() {
66  // Allow this to be called before the thread has started.
67  if (!thread_running_) {
68    return;
69  }
70  thread_running_ = false;
71  int retval = pthread_mutex_lock(&queued_lines_mutex_);
72  LOGGER_ASSERT(0 == retval);
73  bool need_cond_signal = queued_lines_.empty();
74  queued_lines_.push_back(NULL);
75  retval = pthread_mutex_unlock(&queued_lines_mutex_);
76  LOGGER_ASSERT(0 == retval);
77  if (need_cond_signal) {
78    retval = pthread_cond_signal(&queued_lines_cond_);
79    LOGGER_ASSERT(0 == retval);
80  }
81  retval = pthread_join(thread_, NULL);
82  LOGGER_ASSERT(0 == retval);
83}
84
85Logger::Logger()
86    : verbosity_(20),
87      log_fd_(-1),
88      thread_running_(false),
89      log_timestamps_(true) {
90  LOGGER_ASSERT(0 == pthread_mutex_init(&queued_lines_mutex_, NULL));
91  LOGGER_ASSERT(0 == pthread_cond_init(&queued_lines_cond_, NULL));
92  LOGGER_ASSERT(0 == pthread_cond_init(&full_queue_cond_, NULL));
93}
94
95Logger::~Logger() {
96  LOGGER_ASSERT(0 == pthread_mutex_destroy(&queued_lines_mutex_));
97  LOGGER_ASSERT(0 == pthread_cond_destroy(&queued_lines_cond_));
98  LOGGER_ASSERT(0 == pthread_cond_destroy(&full_queue_cond_));
99}
100
101void Logger::QueueLogLine(string *line) {
102  LOGGER_ASSERT(line != NULL);
103  LOGGER_ASSERT(0 == pthread_mutex_lock(&queued_lines_mutex_));
104  if (thread_running_) {
105    if (queued_lines_.size() >= kMaxQueueSize) {
106      LOGGER_ASSERT(0 == pthread_cond_wait(&full_queue_cond_,
107                                           &queued_lines_mutex_));
108    }
109    if (queued_lines_.empty()) {
110      LOGGER_ASSERT(0 == pthread_cond_signal(&queued_lines_cond_));
111    }
112    queued_lines_.push_back(line);
113  } else {
114    WriteAndDeleteLogLine(line);
115  }
116  LOGGER_ASSERT(0 == pthread_mutex_unlock(&queued_lines_mutex_));
117}
118
119void Logger::WriteAndDeleteLogLine(string *line) {
120  LOGGER_ASSERT(line != NULL);
121  ssize_t bytes_written;
122  if (log_fd_ >= 0) {
123    bytes_written = write(log_fd_, line->data(), line->size());
124    LOGGER_ASSERT(bytes_written == static_cast<ssize_t>(line->size()));
125  }
126  bytes_written = write(STDOUT_FILENO, line->data(), line->size());
127  LOGGER_ASSERT(bytes_written == static_cast<ssize_t>(line->size()));
128  delete line;
129}
130
131void *Logger::StartRoutine(void *ptr) {
132  Logger *self = static_cast<Logger*>(ptr);
133  self->ThreadMain();
134  return NULL;
135}
136
137void Logger::ThreadMain() {
138  vector<string*> local_queue;
139  LOGGER_ASSERT(0 == pthread_mutex_lock(&queued_lines_mutex_));
140
141  for (;;) {
142    if (queued_lines_.empty()) {
143      LOGGER_ASSERT(0 == pthread_cond_wait(&queued_lines_cond_,
144                                           &queued_lines_mutex_));
145      continue;
146    }
147
148    // We move the log lines into a local queue so we can release the lock
149    // while writing them to disk, preventing other threads from blocking on
150    // our writes.
151    local_queue.swap(queued_lines_);
152    if (local_queue.size() >= kMaxQueueSize) {
153      LOGGER_ASSERT(0 == pthread_cond_broadcast(&full_queue_cond_));
154    }
155
156    // Unlock while we process our local queue.
157    LOGGER_ASSERT(0 == pthread_mutex_unlock(&queued_lines_mutex_));
158    for (vector<string*>::const_iterator it = local_queue.begin();
159         it != local_queue.end(); ++it) {
160      if (*it == NULL) {
161        // NULL is guaranteed to be at the end.
162        return;
163      }
164      WriteAndDeleteLogLine(*it);
165    }
166    local_queue.clear();
167    // We must hold the lock at the start of each iteration of this for loop.
168    LOGGER_ASSERT(0 == pthread_mutex_lock(&queued_lines_mutex_));
169  }
170}
171