src/basic/log.h

   1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
   2 #pragma once
   3
   4 #include <stdarg.h>
   5 #include <stdbool.h>
   6 #include <stdlib.h>
   7 #include <string.h>
   8 #include <syslog.h>
   9
  10 #include "list.h"
  11 #include "macro.h"
  12 #include "ratelimit.h"
  13 #include "stdio-util.h"
  14
  15 /* Some structures we reference but don't want to pull in headers for */
  16 struct iovec;
  17 struct signalfd_siginfo;
  18
  19 typedef enum LogTarget{
  20         LOG_TARGET_CONSOLE,
  21         LOG_TARGET_CONSOLE_PREFIXED,
  22         LOG_TARGET_KMSG,
  23         LOG_TARGET_JOURNAL,
  24         LOG_TARGET_JOURNAL_OR_KMSG,
  25         LOG_TARGET_SYSLOG,
  26         LOG_TARGET_SYSLOG_OR_KMSG,
  27         LOG_TARGET_AUTO, /* console if stderr is not journal, JOURNAL_OR_KMSG otherwise */
  28         LOG_TARGET_NULL,
  29         _LOG_TARGET_MAX,
  30         _LOG_TARGET_INVALID = -EINVAL,
  31 } LogTarget;
  32
  33 /* This log level disables logging completely. It can only be passed to log_set_max_level() and cannot be
  34  * used a regular log level. */
  35 #define LOG_NULL (LOG_EMERG - 1)
  36
  37 /* Note to readers: << and >> have lower precedence (are evaluated earlier) than & and | */
  38 #define SYNTHETIC_ERRNO(num)                (1 << 30 | (num))
  39 #define IS_SYNTHETIC_ERRNO(val)             ((val) >> 30 & 1)
  40 #define ERRNO_VALUE(val)                    (abs(val) & ~(1 << 30))
  41
  42 /* The callback function to be invoked when syntax warnings are seen
  43  * in the unit files. */
  44 typedef void (*log_syntax_callback_t)(const char *unit, int level, void *userdata);
  45 void set_log_syntax_callback(log_syntax_callback_t cb, void *userdata);
  46
  47 static inline void clear_log_syntax_callback(dummy_t *dummy) {
  48           set_log_syntax_callback(/* cb= */ NULL, /* userdata= */ NULL);
  49 }
  50
  51 const char *log_target_to_string(LogTarget target) _const_;
  52 LogTarget log_target_from_string(const char *s) _pure_;
  53 void log_set_target(LogTarget target);
  54 int log_set_target_from_string(const char *e);
  55 LogTarget log_get_target(void) _pure_;
  56
  57 void log_set_max_level(int level);
  58 int log_set_max_level_from_string(const char *e);
  59 int log_get_max_level(void) _pure_;
  60
  61 void log_set_facility(int facility);
  62
  63 void log_show_color(bool b);
  64 bool log_get_show_color(void) _pure_;
  65 void log_show_location(bool b);
  66 bool log_get_show_location(void) _pure_;
  67 void log_show_time(bool b);
  68 bool log_get_show_time(void) _pure_;
  69 void log_show_tid(bool b);
  70 bool log_get_show_tid(void) _pure_;
  71
  72 int log_show_color_from_string(const char *e);
  73 int log_show_location_from_string(const char *e);
  74 int log_show_time_from_string(const char *e);
  75 int log_show_tid_from_string(const char *e);
  76
  77 /* Functions below that open and close logs or configure logging based on the
  78  * environment should not be called from library code — this is always a job
  79  * for the application itself. */
  80
  81 assert_cc(STRLEN(__FILE__) > STRLEN(RELATIVE_SOURCE_PATH) + 1);
  82 #define PROJECT_FILE (&__FILE__[STRLEN(RELATIVE_SOURCE_PATH) + 1])
  83
  84 int log_open(void);
  85 void log_close(void);
  86 void log_forget_fds(void);
  87
  88 void log_parse_environment_variables(void);
  89 void log_parse_environment(void);
  90
  91 int log_dispatch_internal(
  92                 int level,
  93                 int error,
  94                 const char *file,
  95                 int line,
  96                 const char *func,
  97                 const char *object_field,
  98                 const char *object,
  99                 const char *extra,
 100                 const char *extra_field,
 101                 char *buffer);
 102
 103 int log_internal(
 104                 int level,
 105                 int error,
 106                 const char *file,
 107                 int line,
 108                 const char *func,
 109                 const char *format, ...) _printf_(6,7);
 110
 111 int log_internalv(
 112                 int level,
 113                 int error,
 114                 const char *file,
 115                 int line,
 116                 const char *func,
 117                 const char *format,
 118                 va_list ap) _printf_(6,0);
 119
 120 int log_object_internalv(
 121                 int level,
 122                 int error,
 123                 const char *file,
 124                 int line,
 125                 const char *func,
 126                 const char *object_field,
 127                 const char *object,
 128                 const char *extra_field,
 129                 const char *extra,
 130                 const char *format,
 131                 va_list ap) _printf_(10,0);
 132
 133 int log_object_internal(
 134                 int level,
 135                 int error,
 136                 const char *file,
 137                 int line,
 138                 const char *func,
 139                 const char *object_field,
 140                 const char *object,
 141                 const char *extra_field,
 142                 const char *extra,
 143                 const char *format, ...) _printf_(10,11);
 144
 145 int log_struct_internal(
 146                 int level,
 147                 int error,
 148                 const char *file,
 149                 int line,
 150                 const char *func,
 151                 const char *format, ...) _printf_(6,0) _sentinel_;
 152
 153 int log_oom_internal(
 154                 int level,
 155                 const char *file,
 156                 int line,
 157                 const char *func);
 158
 159 int log_format_iovec(
 160                 struct iovec *iovec,
 161                 size_t iovec_len,
 162                 size_t *n,
 163                 bool newline_separator,
 164                 int error,
 165                 const char *format,
 166                 va_list ap) _printf_(6, 0);
 167
 168 int log_struct_iovec_internal(
 169                 int level,
 170                 int error,
 171                 const char *file,
 172                 int line,
 173                 const char *func,
 174                 const struct iovec *input_iovec,
 175                 size_t n_input_iovec);
 176
 177 /* This modifies the buffer passed! */
 178 int log_dump_internal(
 179                 int level,
 180                 int error,
 181                 const char *file,
 182                 int line,
 183                 const char *func,
 184                 char *buffer);
 185
 186 /* Logging for various assertions */
 187 _noreturn_ void log_assert_failed(
 188                 const char *text,
 189                 const char *file,
 190                 int line,
 191                 const char *func);
 192
 193 _noreturn_ void log_assert_failed_unreachable(
 194                 const char *file,
 195                 int line,
 196                 const char *func);
 197
 198 void log_assert_failed_return(
 199                 const char *text,
 200                 const char *file,
 201                 int line,
 202                 const char *func);
 203
 204 #define log_dispatch(level, error, buffer)                              \
 205         log_dispatch_internal(level, error, PROJECT_FILE, __LINE__, __func__, NULL, NULL, NULL, NULL, buffer)
 206
 207 /* Logging with level */
 208 #define log_full_errno_zerook(level, error, ...)                        \
 209         ({                                                              \
 210                 int _level = (level), _e = (error);                     \
 211                 _e = (log_get_max_level() >= LOG_PRI(_level))           \
 212                         ? log_internal(_level, _e, PROJECT_FILE, __LINE__, __func__, __VA_ARGS__) \
 213                         : -ERRNO_VALUE(_e);                             \
 214                 _e < 0 ? _e : -ESTRPIPE;                                \
 215         })
 216
 217 #if BUILD_MODE_DEVELOPER && !defined(TEST_CODE)
 218 #  define ASSERT_NON_ZERO(x) assert((x) != 0)
 219 #else
 220 #  define ASSERT_NON_ZERO(x)
 221 #endif
 222
 223 #define log_full_errno(level, error, ...)                               \
 224         ({                                                              \
 225                 int _error = (error);                                   \
 226                 ASSERT_NON_ZERO(_error);                                \
 227                 log_full_errno_zerook(level, _error, __VA_ARGS__);      \
 228         })
 229
 230 #define log_full(level, fmt, ...)                                      \
 231         ({                                                             \
 232                 if (BUILD_MODE_DEVELOPER)                              \
 233                         assert(!strstr(fmt, "%m"));                    \
 234                 (void) log_full_errno_zerook(level, 0, fmt, ##__VA_ARGS__); \
 235         })
 236
 237 int log_emergency_level(void);
 238
 239 /* Normal logging */
 240 #define log_debug(...)     log_full(LOG_DEBUG,   __VA_ARGS__)
 241 #define log_info(...)      log_full(LOG_INFO,    __VA_ARGS__)
 242 #define log_notice(...)    log_full(LOG_NOTICE,  __VA_ARGS__)
 243 #define log_warning(...)   log_full(LOG_WARNING, __VA_ARGS__)
 244 #define log_error(...)     log_full(LOG_ERR,     __VA_ARGS__)
 245 #define log_emergency(...) log_full(log_emergency_level(), __VA_ARGS__)
 246
 247 /* Logging triggered by an errno-like error */
 248 #define log_debug_errno(error, ...)     log_full_errno(LOG_DEBUG,   error, __VA_ARGS__)
 249 #define log_info_errno(error, ...)      log_full_errno(LOG_INFO,    error, __VA_ARGS__)
 250 #define log_notice_errno(error, ...)    log_full_errno(LOG_NOTICE,  error, __VA_ARGS__)
 251 #define log_warning_errno(error, ...)   log_full_errno(LOG_WARNING, error, __VA_ARGS__)
 252 #define log_error_errno(error, ...)     log_full_errno(LOG_ERR,     error, __VA_ARGS__)
 253 #define log_emergency_errno(error, ...) log_full_errno(log_emergency_level(), error, __VA_ARGS__)
 254
 255 /* This logs at the specified level the first time it is called, and then
 256  * logs at debug. If the specified level is debug, this logs only the first
 257  * time it is called. */
 258 #define log_once(level, ...)                                             \
 259         ({                                                               \
 260                 if (ONCE)                                                \
 261                         log_full(level, __VA_ARGS__);                    \
 262                 else if (LOG_PRI(level) != LOG_DEBUG)                    \
 263                         log_debug(__VA_ARGS__);                          \
 264         })
 265
 266 #define log_once_errno(level, error, ...)                                \
 267         ({                                                               \
 268                 int _err = (error);                                      \
 269                 if (ONCE)                                                \
 270                         _err = log_full_errno(level, _err, __VA_ARGS__); \
 271                 else if (LOG_PRI(level) != LOG_DEBUG)                    \
 272                         _err = log_debug_errno(_err, __VA_ARGS__);       \
 273                 else                                                     \
 274                         _err = -ERRNO_VALUE(_err);                       \
 275                 _err;                                                    \
 276         })
 277
 278 #if LOG_TRACE
 279 #  define log_trace(...)          log_debug(__VA_ARGS__)
 280 #  define log_trace_errno(...)    log_debug_errno(__VA_ARGS__)
 281 #else
 282 #  define log_trace(...)          do {} while (0)
 283 #  define log_trace_errno(e, ...) (-ERRNO_VALUE(e))
 284 #endif
 285
 286 /* Structured logging */
 287 #define log_struct_errno(level, error, ...)                             \
 288         log_struct_internal(level, error, PROJECT_FILE, __LINE__, __func__, __VA_ARGS__, NULL)
 289 #define log_struct(level, ...) log_struct_errno(level, 0, __VA_ARGS__)
 290
 291 #define log_struct_iovec_errno(level, error, iovec, n_iovec)            \
 292         log_struct_iovec_internal(level, error, PROJECT_FILE, __LINE__, __func__, iovec, n_iovec)
 293 #define log_struct_iovec(level, iovec, n_iovec) log_struct_iovec_errno(level, 0, iovec, n_iovec)
 294
 295 /* This modifies the buffer passed! */
 296 #define log_dump(level, buffer)                                         \
 297         log_dump_internal(level, 0, PROJECT_FILE, __LINE__, __func__, buffer)
 298
 299 #define log_oom() log_oom_internal(LOG_ERR, PROJECT_FILE, __LINE__, __func__)
 300 #define log_oom_debug() log_oom_internal(LOG_DEBUG, PROJECT_FILE, __LINE__, __func__)
 301
 302 bool log_on_console(void) _pure_;
 303
 304 /* Helper to wrap the main message in structured logging. The macro doesn't do much,
 305  * except to provide visual grouping of the format string and its arguments. */
 306 #if LOG_MESSAGE_VERIFICATION || defined(__COVERITY__)
 307 /* Do a fake formatting of the message string to let the scanner verify the arguments against the format
 308  * message. The variable will never be set to true, but we don't tell the compiler that :) */
 309 extern bool _log_message_dummy;
 310 #  define LOG_MESSAGE(fmt, ...) "MESSAGE=%.0d" fmt, (_log_message_dummy && printf(fmt, ##__VA_ARGS__)), ##__VA_ARGS__
 311 #else
 312 #  define LOG_MESSAGE(fmt, ...) "MESSAGE=" fmt, ##__VA_ARGS__
 313 #endif
 314
 315 void log_received_signal(int level, const struct signalfd_siginfo *si);
 316
 317 /* If turned on, any requests for a log target involving "syslog" will be implicitly upgraded to the equivalent journal target */
 318 void log_set_upgrade_syslog_to_journal(bool b);
 319
 320 /* If turned on, and log_open() is called, we'll not use STDERR_FILENO for logging ever, but rather open /dev/console */
 321 void log_set_always_reopen_console(bool b);
 322
 323 /* If turned on, we'll open the log stream implicitly if needed on each individual log call. This is normally not
 324  * desired as we want to reuse our logging streams. It is useful however  */
 325 void log_set_open_when_needed(bool b);
 326
 327 /* If turned on, then we'll never use IPC-based logging, i.e. never log to syslog or the journal. We'll only log to
 328  * stderr, the console or kmsg */
 329 void log_set_prohibit_ipc(bool b);
 330
 331 int log_dup_console(void);
 332
 333 int log_syntax_internal(
 334                 const char *unit,
 335                 int level,
 336                 const char *config_file,
 337                 unsigned config_line,
 338                 int error,
 339                 const char *file,
 340                 int line,
 341                 const char *func,
 342                 const char *format, ...) _printf_(9, 10);
 343
 344 int log_syntax_invalid_utf8_internal(
 345                 const char *unit,
 346                 int level,
 347                 const char *config_file,
 348                 unsigned config_line,
 349                 const char *file,
 350                 int line,
 351                 const char *func,
 352                 const char *rvalue);
 353
 354 #define log_syntax(unit, level, config_file, config_line, error, ...)   \
 355         ({                                                              \
 356                 int _level = (level), _e = (error);                     \
 357                 (log_get_max_level() >= LOG_PRI(_level))                \
 358                         ? log_syntax_internal(unit, _level, config_file, config_line, _e, PROJECT_FILE, __LINE__, __func__, __VA_ARGS__) \
 359                         : -ERRNO_VALUE(_e);                             \
 360         })
 361
 362 #define log_syntax_invalid_utf8(unit, level, config_file, config_line, rvalue) \
 363         ({                                                              \
 364                 int _level = (level);                                   \
 365                 (log_get_max_level() >= LOG_PRI(_level))                \
 366                         ? log_syntax_invalid_utf8_internal(unit, _level, config_file, config_line, PROJECT_FILE, __LINE__, __func__, rvalue) \
 367                         : -EINVAL;                                      \
 368         })
 369
 370 #define DEBUG_LOGGING _unlikely_(log_get_max_level() >= LOG_DEBUG)
 371
 372 void log_setup(void);
 373
 374 typedef struct LogRateLimit {
 375         int error;
 376         int level;
 377         RateLimit ratelimit;
 378 } LogRateLimit;
 379
 380 #define log_ratelimit_internal(_level, _error, _ratelimit, _format, _file, _line, _func, ...)        \
 381 ({                                                                              \
 382         int _log_ratelimit_error = (_error);                                    \
 383         int _log_ratelimit_level = (_level);                                    \
 384         static LogRateLimit _log_ratelimit = {                                  \
 385                 .ratelimit = (_ratelimit),                                      \
 386         };                                                                      \
 387         unsigned _num_dropped_errors = ratelimit_num_dropped(&_log_ratelimit.ratelimit); \
 388         if (_log_ratelimit_error != _log_ratelimit.error || _log_ratelimit_level != _log_ratelimit.level) { \
 389                 ratelimit_reset(&_log_ratelimit.ratelimit);                     \
 390                 _log_ratelimit.error = _log_ratelimit_error;                    \
 391                 _log_ratelimit.level = _log_ratelimit_level;                    \
 392         }                                                                       \
 393         if (log_get_max_level() == LOG_DEBUG || ratelimit_below(&_log_ratelimit.ratelimit)) \
 394                 _log_ratelimit_error = _num_dropped_errors > 0                  \
 395                 ? log_internal(_log_ratelimit_level, _log_ratelimit_error, _file, _line, _func, _format " (Dropped %u similar message(s))", ##__VA_ARGS__, _num_dropped_errors) \
 396                 : log_internal(_log_ratelimit_level, _log_ratelimit_error, _file, _line, _func, _format, ##__VA_ARGS__); \
 397         _log_ratelimit_error;                                                   \
 398 })
 399
 400 #define log_ratelimit_full_errno(level, error, _ratelimit, format, ...)             \
 401         ({                                                              \
 402                 int _level = (level), _e = (error);                     \
 403                 _e = (log_get_max_level() >= LOG_PRI(_level))           \
 404                         ? log_ratelimit_internal(_level, _e, _ratelimit, format, PROJECT_FILE, __LINE__, __func__, ##__VA_ARGS__) \
 405                         : -ERRNO_VALUE(_e);                             \
 406                 _e < 0 ? _e : -ESTRPIPE;                                \
 407         })
 408
 409 #define log_ratelimit_full(level, _ratelimit, format, ...)                          \
 410         log_ratelimit_full_errno(level, 0, _ratelimit, format, ##__VA_ARGS__)
 411
 412 /* Normal logging */
 413 #define log_ratelimit_info(...)      log_ratelimit_full(LOG_INFO,    __VA_ARGS__)
 414 #define log_ratelimit_notice(...)    log_ratelimit_full(LOG_NOTICE,  __VA_ARGS__)
 415 #define log_ratelimit_warning(...)   log_ratelimit_full(LOG_WARNING, __VA_ARGS__)
 416 #define log_ratelimit_error(...)     log_ratelimit_full(LOG_ERR,     __VA_ARGS__)
 417 #define log_ratelimit_emergency(...) log_ratelimit_full(log_emergency_level(), __VA_ARGS__)
 418
 419 /* Logging triggered by an errno-like error */
 420 #define log_ratelimit_info_errno(error, ...)      log_ratelimit_full_errno(LOG_INFO,    error, __VA_ARGS__)
 421 #define log_ratelimit_notice_errno(error, ...)    log_ratelimit_full_errno(LOG_NOTICE,  error, __VA_ARGS__)
 422 #define log_ratelimit_warning_errno(error, ...)   log_ratelimit_full_errno(LOG_WARNING, error, __VA_ARGS__)
 423 #define log_ratelimit_error_errno(error, ...)     log_ratelimit_full_errno(LOG_ERR,     error, __VA_ARGS__)
 424 #define log_ratelimit_emergency_errno(error, ...) log_ratelimit_full_errno(log_emergency_level(), error, __VA_ARGS__)
 425
 426 /*
 427  * The log context allows attaching extra metadata to log messages written to the journal via log.h. We keep
 428  * track of a thread local log context onto which we can push extra metadata fields that should be logged.
 429  *
 430  * LOG_CONTEXT_PUSH() will add the provided field to the log context and will remove it again when the
 431  * current block ends. LOG_CONTEXT_PUSH_STRV() will do the same but for all fields in the given strv.
 432  * LOG_CONTEXT_PUSHF() is like LOG_CONTEXT_PUSH() but takes a format string and arguments.
 433  *
 434  * Using the macros is as simple as putting them anywhere inside a block to add a field to all following log
 435  * messages logged from inside that block.
 436  *
 437  * void myfunction(...) {
 438  *         ...
 439  *
 440  *         LOG_CONTEXT_PUSHF("MYMETADATA=%s", "abc");
 441  *
 442  *         // Every journal message logged will now have the MYMETADATA=abc
 443  *         // field included.
 444  * }
 445  *
 446  * One special case to note is async code, where we use callbacks that are invoked to continue processing
 447  * when some event occurs. For async code, there's usually an associated "userdata" struct containing all the
 448  * information associated with the async operation. In this "userdata" struct, we can store a log context
 449  * allocated with log_context_new() and freed with log_context_free(). We can then add and remove fields to
 450  * the `fields` member of the log context object and all those fields will be logged along with each log
 451  * message.
 452  */
 453
 454 typedef struct LogContext LogContext;
 455
 456 bool log_context_enabled(void);
 457
 458 LogContext* log_context_attach(LogContext *c);
 459 LogContext* log_context_detach(LogContext *c);
 460
 461 LogContext* log_context_new(char **fields, bool owned);
 462 LogContext* log_context_free(LogContext *c);
 463
 464 /* Same as log_context_new(), but frees the given fields strv on failure. */
 465 LogContext* log_context_new_consume(char **fields);
 466
 467 /* Returns the number of attached log context objects. */
 468 size_t log_context_num_contexts(void);
 469 /* Returns the number of fields in all attached log contexts. */
 470 size_t log_context_num_fields(void);
 471
 472 DEFINE_TRIVIAL_CLEANUP_FUNC(LogContext*, log_context_detach);
 473 DEFINE_TRIVIAL_CLEANUP_FUNC(LogContext*, log_context_free);
 474
 475 #define LOG_CONTEXT_PUSH(...) \
 476         LOG_CONTEXT_PUSH_STRV(STRV_MAKE(__VA_ARGS__))
 477
 478 #define LOG_CONTEXT_PUSHF(...) \
 479         LOG_CONTEXT_PUSH(snprintf_ok((char[LINE_MAX]) {}, LINE_MAX, __VA_ARGS__))
 480
 481 #define _LOG_CONTEXT_PUSH_STRV(strv, c) \
 482         _unused_ _cleanup_(log_context_freep) LogContext *c = log_context_new(strv, /*owned=*/ false);
 483
 484 #define LOG_CONTEXT_PUSH_STRV(strv) \
 485         _LOG_CONTEXT_PUSH_STRV(strv, UNIQ_T(c, UNIQ))
 486
 487 /* LOG_CONTEXT_CONSUME_STR()/LOG_CONTEXT_CONSUME_STRV() are identical to
 488  * LOG_CONTEXT_PUSH_STR()/LOG_CONTEXT_PUSH_STRV() except they take ownership of the given str/strv argument.
 489  */
 490
 491 #define _LOG_CONTEXT_CONSUME_STR(s, c, strv) \
 492         _unused_ _cleanup_strv_free_ strv = strv_new(s);                                                \
 493         if (!strv)                                                                                      \
 494                 free(s);                                                                                \
 495         _unused_ _cleanup_(log_context_freep) LogContext *c = log_context_new_consume(TAKE_PTR(strv))
 496
 497 #define LOG_CONTEXT_CONSUME_STR(s) \
 498         _LOG_CONTEXT_CONSUME_STR(s, UNIQ_T(c, UNIQ), UNIQ_T(sv, UNIQ))
 499
 500 #define _LOG_CONTEXT_CONSUME_STRV(strv, c) \
 501         _unused_ _cleanup_(log_context_freep) LogContext *c = log_context_new_consume(strv);
 502
 503 #define LOG_CONTEXT_CONSUME_STRV(strv) \
 504         _LOG_CONTEXT_CONSUME_STRV(strv, UNIQ_T(c, UNIQ))