logging.h raw
1 // Copyright (c) 2009-2010 Satoshi Nakamoto
2 // Copyright (c) 2009-present The Bitcoin Core developers
3 // Distributed under the MIT software license, see the accompanying
4 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
5
6 #ifndef BITCOIN_LOGGING_H
7 #define BITCOIN_LOGGING_H
8
9 #include <crypto/siphash.h>
10 #include <logging/categories.h> // IWYU pragma: export
11 #include <span.h>
12 #include <util/byte_units.h>
13 #include <util/fs.h>
14 #include <util/log.h> // IWYU pragma: export
15 #include <util/stdmutex.h>
16 #include <util/string.h>
17 #include <util/time.h>
18
19 #include <atomic>
20 #include <cstdint>
21 #include <cstring>
22 #include <functional>
23 #include <list>
24 #include <memory>
25 #include <optional>
26 #include <string>
27 #include <unordered_map>
28 #include <vector>
29
30 static const bool DEFAULT_LOGTIMEMICROS = false;
31 static const bool DEFAULT_LOGIPS = false;
32 static const bool DEFAULT_LOGTIMESTAMPS = true;
33 static const bool DEFAULT_LOGTHREADNAMES = false;
34 static const bool DEFAULT_LOGSOURCELOCATIONS = false;
35 static constexpr bool DEFAULT_LOGLEVELALWAYS = false;
36 extern const char * const DEFAULT_DEBUGLOGFILE;
37
38 extern bool fLogIPs;
39
40 struct SourceLocationEqual {
41 bool operator()(const SourceLocation& lhs, const SourceLocation& rhs) const noexcept
42 {
43 return lhs.line() == rhs.line() && std::string_view(lhs.file_name()) == std::string_view(rhs.file_name());
44 }
45 };
46
47 struct SourceLocationHasher {
48 size_t operator()(const SourceLocation& s) const noexcept
49 {
50 // Use CSipHasher(0, 0) as a simple way to get uniform distribution.
51 return size_t(CSipHasher(0, 0)
52 .Write(s.line())
53 .Write(MakeUCharSpan(std::string_view{s.file_name()}))
54 .Finalize());
55 }
56 };
57
58 struct LogCategory {
59 std::string category;
60 bool active;
61 };
62
63 namespace BCLog {
64 constexpr auto DEFAULT_LOG_LEVEL{Level::Debug};
65 constexpr size_t DEFAULT_MAX_LOG_BUFFER{1'000'000}; // buffer up to 1MB of log data prior to StartLogging
66 constexpr uint64_t RATELIMIT_MAX_BYTES{1_MiB}; // maximum number of bytes per source location that can be logged within the RATELIMIT_WINDOW
67 constexpr auto RATELIMIT_WINDOW{1h}; // time window after which log ratelimit stats are reset
68 constexpr bool DEFAULT_LOGRATELIMIT{true};
69
70 //! Fixed window rate limiter for logging.
71 class LogRateLimiter
72 {
73 public:
74 //! Keeps track of an individual source location and how many available bytes are left for logging from it.
75 struct Stats {
76 //! Remaining bytes
77 uint64_t m_available_bytes;
78 //! Number of bytes that were consumed but didn't fit in the available bytes.
79 uint64_t m_dropped_bytes{0};
80
81 Stats(uint64_t max_bytes) : m_available_bytes{max_bytes} {}
82 //! Updates internal accounting and returns true if enough available_bytes were remaining
83 bool Consume(uint64_t bytes);
84 };
85
86 private:
87 mutable StdMutex m_mutex;
88
89 //! Stats for each source location that has attempted to log something.
90 std::unordered_map<SourceLocation, Stats, SourceLocationHasher, SourceLocationEqual> m_source_locations GUARDED_BY(m_mutex);
91 //! Whether any log locations are suppressed. Cached view on m_source_locations for performance reasons.
92 std::atomic<bool> m_suppression_active{false};
93 LogRateLimiter(uint64_t max_bytes, std::chrono::seconds reset_window);
94
95 public:
96 using SchedulerFunction = std::function<void(std::function<void()>, std::chrono::milliseconds)>;
97 /**
98 * @param scheduler_func Callable object used to schedule resetting the window. The first
99 * parameter is the function to be executed, and the second is the
100 * reset_window interval.
101 * @param max_bytes Maximum number of bytes that can be logged for each source
102 * location.
103 * @param reset_window Time window after which the stats are reset.
104 */
105 static std::shared_ptr<LogRateLimiter> Create(
106 SchedulerFunction&& scheduler_func,
107 uint64_t max_bytes,
108 std::chrono::seconds reset_window);
109 //! Maximum number of bytes logged per location per window.
110 const uint64_t m_max_bytes;
111 //! Interval after which the window is reset.
112 const std::chrono::seconds m_reset_window;
113 //! Suppression status of a source log location.
114 enum class Status {
115 UNSUPPRESSED, // string fits within the limit
116 NEWLY_SUPPRESSED, // suppression has started since this string
117 STILL_SUPPRESSED, // suppression is still ongoing
118 };
119 //! Consumes `source_loc`'s available bytes corresponding to the size of the (formatted)
120 //! `str` and returns its status.
121 [[nodiscard]] Status Consume(
122 const SourceLocation& source_loc,
123 const std::string& str) EXCLUSIVE_LOCKS_REQUIRED(!m_mutex);
124 //! Resets all usage to zero. Called periodically by the scheduler.
125 void Reset() EXCLUSIVE_LOCKS_REQUIRED(!m_mutex);
126 //! Returns true if any log locations are currently being suppressed.
127 bool SuppressionsActive() const { return m_suppression_active; }
128 };
129
130 class Logger
131 {
132 private:
133 mutable StdMutex m_cs; // Can not use Mutex from sync.h because in debug mode it would cause a deadlock when a potential deadlock was detected
134
135 FILE* m_fileout GUARDED_BY(m_cs) = nullptr;
136 std::list<util::log::Entry> m_msgs_before_open GUARDED_BY(m_cs);
137 bool m_buffering GUARDED_BY(m_cs) = true; //!< Buffer messages before logging can be started.
138 size_t m_max_buffer_memusage GUARDED_BY(m_cs){DEFAULT_MAX_LOG_BUFFER};
139 size_t m_cur_buffer_memusage GUARDED_BY(m_cs){0};
140 size_t m_buffer_lines_discarded GUARDED_BY(m_cs){0};
141
142 //! Manages the rate limiting of each log location.
143 std::shared_ptr<LogRateLimiter> m_limiter GUARDED_BY(m_cs);
144
145 //! Category-specific log level. Overrides `m_log_level`.
146 std::unordered_map<LogFlags, Level> m_category_log_levels GUARDED_BY(m_cs);
147
148 //! If there is no category-specific log level, all logs with a severity
149 //! level lower than `m_log_level` will be ignored.
150 std::atomic<Level> m_log_level{DEFAULT_LOG_LEVEL};
151
152 /** Log categories bitfield. */
153 std::atomic<CategoryMask> m_categories{BCLog::NONE};
154
155 std::string Format(const util::log::Entry& entry) const;
156
157 std::string LogTimestampStr(SystemClock::time_point now, std::chrono::seconds mocktime) const;
158
159 /** Slots that connect to the print signal */
160 std::list<std::function<void(const std::string&)>> m_print_callbacks GUARDED_BY(m_cs){};
161
162 /** Send an entry to the log output (internal) */
163 void LogPrint_(util::log::Entry log_entry) EXCLUSIVE_LOCKS_REQUIRED(m_cs);
164
165 std::string GetLogPrefix(LogFlags category, Level level) const;
166
167 public:
168 bool m_print_to_console = false;
169 bool m_print_to_file = false;
170
171 bool m_log_timestamps = DEFAULT_LOGTIMESTAMPS;
172 bool m_log_time_micros = DEFAULT_LOGTIMEMICROS;
173 bool m_log_threadnames = DEFAULT_LOGTHREADNAMES;
174 bool m_log_sourcelocations = DEFAULT_LOGSOURCELOCATIONS;
175 bool m_always_print_category_level = DEFAULT_LOGLEVELALWAYS;
176
177 fs::path m_file_path;
178 std::atomic<bool> m_reopen_file{false};
179
180 /** Send an entry to the log output */
181 void LogPrint(util::log::Entry log_entry) EXCLUSIVE_LOCKS_REQUIRED(!m_cs);
182
183 /** Returns whether logs will be written to any output */
184 bool Enabled() const EXCLUSIVE_LOCKS_REQUIRED(!m_cs)
185 {
186 STDLOCK(m_cs);
187 return m_buffering || m_print_to_console || m_print_to_file || !m_print_callbacks.empty();
188 }
189
190 /** Connect a slot to the print signal and return the connection */
191 std::list<std::function<void(const std::string&)>>::iterator PushBackCallback(std::function<void(const std::string&)> fun) EXCLUSIVE_LOCKS_REQUIRED(!m_cs)
192 {
193 STDLOCK(m_cs);
194 m_print_callbacks.push_back(std::move(fun));
195 return --m_print_callbacks.end();
196 }
197
198 /** Delete a connection */
199 void DeleteCallback(std::list<std::function<void(const std::string&)>>::iterator it) EXCLUSIVE_LOCKS_REQUIRED(!m_cs)
200 {
201 STDLOCK(m_cs);
202 m_print_callbacks.erase(it);
203 }
204
205 size_t NumConnections() EXCLUSIVE_LOCKS_REQUIRED(!m_cs)
206 {
207 STDLOCK(m_cs);
208 return m_print_callbacks.size();
209 }
210
211 /** Start logging (and flush all buffered messages) */
212 bool StartLogging() EXCLUSIVE_LOCKS_REQUIRED(!m_cs);
213 /** Only for testing */
214 void DisconnectTestLogger() EXCLUSIVE_LOCKS_REQUIRED(!m_cs);
215
216 void SetRateLimiting(std::shared_ptr<LogRateLimiter> limiter) EXCLUSIVE_LOCKS_REQUIRED(!m_cs)
217 {
218 STDLOCK(m_cs);
219 m_limiter = std::move(limiter);
220 }
221
222 /** Disable logging
223 * This offers a slight speedup and slightly smaller memory usage
224 * compared to leaving the logging system in its default state.
225 * Mostly intended for libbitcoin-kernel apps that don't want any logging.
226 * Should be used instead of StartLogging().
227 */
228 void DisableLogging() EXCLUSIVE_LOCKS_REQUIRED(!m_cs);
229
230 void ShrinkDebugFile() EXCLUSIVE_LOCKS_REQUIRED(!m_cs);
231
232 std::unordered_map<LogFlags, Level> CategoryLevels() const EXCLUSIVE_LOCKS_REQUIRED(!m_cs)
233 {
234 STDLOCK(m_cs);
235 return m_category_log_levels;
236 }
237 void SetCategoryLogLevel(const std::unordered_map<LogFlags, Level>& levels) EXCLUSIVE_LOCKS_REQUIRED(!m_cs)
238 {
239 STDLOCK(m_cs);
240 m_category_log_levels = levels;
241 }
242 void AddCategoryLogLevel(LogFlags category, Level level) EXCLUSIVE_LOCKS_REQUIRED(!m_cs)
243 {
244 STDLOCK(m_cs);
245 m_category_log_levels[category] = level;
246 }
247 bool SetCategoryLogLevel(std::string_view category_str, std::string_view level_str) EXCLUSIVE_LOCKS_REQUIRED(!m_cs);
248
249 Level LogLevel() const { return m_log_level.load(); }
250 void SetLogLevel(Level level) { m_log_level = level; }
251 bool SetLogLevel(std::string_view level);
252
253 CategoryMask GetCategoryMask() const { return m_categories.load(); }
254
255 void EnableCategory(LogFlags flag);
256 bool EnableCategory(std::string_view str);
257 void DisableCategory(LogFlags flag);
258 bool DisableCategory(std::string_view str);
259
260 bool WillLogCategory(LogFlags category) const;
261 bool WillLogCategoryLevel(LogFlags category, Level level) const EXCLUSIVE_LOCKS_REQUIRED(!m_cs);
262
263 /** Returns a vector of the log categories in alphabetical order. */
264 std::vector<LogCategory> LogCategoriesList() const;
265 /** Returns a string with the log categories in alphabetical order. */
266 std::string LogCategoriesString() const
267 {
268 return util::Join(LogCategoriesList(), ", ", [&](const LogCategory& i) { return i.category; });
269 };
270
271 //! Returns a string with all user-selectable log levels.
272 std::string LogLevelsString() const;
273
274 //! Returns the string representation of a log level.
275 static std::string LogLevelToStr(BCLog::Level level);
276
277 bool DefaultShrinkDebugFile() const;
278
279 //! Return log flag if str parses as a log category.
280 static std::optional<BCLog::LogFlags> GetLogCategory(std::string_view str);
281 };
282 } // namespace BCLog
283
284 BCLog::Logger& LogInstance();
285
286 #endif // BITCOIN_LOGGING_H
287