log.c File Reference

Functions to send messages to log files or the console. More...

#include "orconfig.h"
#include <stdarg.h>
#include <assert.h>
#include <stdlib.h>
#include <string.h>
#include "compat.h"
#include "util.h"
#include "torlog.h"
#include "container.h"
#include "micro-revision.i"

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Data Structures
struct	logfile_t
struct	pending_log_message_t

Macros
#define	LOG_PRIVATE
#define	SEVERITY_MASK_IDX(sev)   ((sev) - LOG_ERR)
#define	raw_assert(x)   assert(x)
#define	log_free(lg)   FREE_AND_NULL(logfile_t, log_free_, (lg))
#define	MAX_STARTUP_MSG_LEN   (1<<16)
#define	LOCK_LOGS()
#define	UNLOCK_LOGS()
#define	pending_log_message_free(msg)   FREE_AND_NULL(pending_log_message_t, pending_log_message_free_, (msg))
#define	MAX_SIGSAFE_FDS   8
#define	TRUNCATED_STR   "[...truncated]"
#define	TRUNCATED_STR_LEN   14

Typedefs
typedef struct logfile_t	logfile_t
typedef struct pending_log_message_t	pending_log_message_t

Functions
void	log_set_application_name (const char *name)
int	log_message_is_interesting (int severity, log_domain_mask_t domain)
void	tor_log_string (int severity, log_domain_mask_t domain, const char *function, const char *string)
void	set_log_time_granularity (int granularity_msec)
	MOCK_IMPL (STATIC void, logv,(int severity, log_domain_mask_t domain, const char *funcname, const char *suffix, const char *format, va_list ap))
void	tor_log (int severity, log_domain_mask_t domain, const char *format,...)
void	tor_log_err_sigsafe (const char *m,...)
int	tor_log_get_sigsafe_err_fds (const int **out)
void	tor_log_update_sigsafe_err_fds (void)
void	tor_log_get_logfile_names (smartlist_t *out)
void	log_fn_ (int severity, log_domain_mask_t domain, const char *fn, const char *format,...)
void	log_fn_ratelim_ (ratelim_t *ratelim, int severity, log_domain_mask_t domain, const char *fn, const char *format,...)
void	logs_free_all (void)
void	set_log_severity_config (int loglevelMin, int loglevelMax, log_severity_list_t *severity_out)
void	add_stream_log (const log_severity_list_t *severity, const char *name, int fd)
void	init_logging (int disable_startup_queue)
void	logs_set_domain_logging (int enabled)
void	add_temp_log (int min_severity)
void	logs_set_pending_callback_callback (pending_callback_callback cb)
int	add_callback_log (const log_severity_list_t *severity, log_callback cb)
void	change_callback_log_severity (int loglevelMin, int loglevelMax, log_callback cb)
void	flush_pending_log_callbacks (void)
void	flush_log_messages_from_startup (void)
void	close_temp_logs (void)
void	rollback_log_changes (void)
void	mark_logs_temp (void)
int	add_file_log (const log_severity_list_t *severity, const char *filename, const int truncate_log)
int	parse_log_level (const char *level)
const char *	log_level_to_string (int level)
int	parse_log_severity_config (const char **cfg_ptr, log_severity_list_t *severity_out)
int	get_min_log_level (void)
void	switch_logs_debug (void)
void	truncate_logs (void)

Variables
const int	LOG_WARN_ = LOG_WARN
const int	LOG_NOTICE_ = LOG_NOTICE
const log_domain_mask_t	LD_GENERAL_ = LD_GENERAL
const log_domain_mask_t	LD_NET_ = LD_NET
int	log_global_min_severity_ = LOG_NOTICE

Detailed Description

Functions to send messages to log files or the console.

Macro Definition Documentation

LOCK_LOGS

#define LOCK_LOGS

(

)

Value:

STMT_BEGIN                                          \
  tor_assert(log_mutex_initialized);                                    \
  tor_mutex_acquire(&log_mutex);                                        \
  STMT_END

Lock the log_mutex to prevent others from changing the logfile_t list

MAX_SIGSAFE_FDS

#define MAX_SIGSAFE_FDS   8

Maximum number of fds that will get notifications if we crash

MAX_STARTUP_MSG_LEN

#define MAX_STARTUP_MSG_LEN   (1<<16)

Don't store more than this many bytes of messages while waiting for the logs to get configured.

SEVERITY_MASK_IDX

#define SEVERITY_MASK_IDX

(

sev

)

((sev) - LOG_ERR)

Given a severity, yields an index into log_severity_list_t.masks to use for that severity.

TRUNCATED_STR

#define TRUNCATED_STR   "[...truncated]"

The string we stick at the end of a log message when it is too long, and its length.

UNLOCK_LOGS

#define UNLOCK_LOGS

(

)

Value:

STMT_BEGIN                                        \
  tor_assert(log_mutex_initialized);                                    \
  tor_mutex_release(&log_mutex);                                        \
  STMT_END

Unlock the log_mutex

Typedef Documentation

logfile_t

typedef struct logfile_t logfile_t

Information for a single logfile; only used in log.c

pending_log_message_t

typedef struct pending_log_message_t pending_log_message_t

Represents a log message that we are going to send to callback-driven loggers once we can do so in a non-reentrant way.

Function Documentation

add_callback_log()

int add_callback_log	(	const log_severity_list_t *	severity,
		log_callback	cb
	)

Add a log handler to send messages in severity to the function cb.

add_file_log()

int add_file_log	(	const log_severity_list_t *	severity,
		const char *	filename,
		const int	truncate_log
	)

Add a log handler to send messages to filename. If opening the logfile fails, -1 is returned and errno is set appropriately (by open(2)).

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add_stream_log()

void add_stream_log	(	const log_severity_list_t *	severity,
		const char *	name,
		int	fd
	)

Add a log handler named name to send all messages in severity to fd. Steals a reference to severity; the caller must not use it after calling this function.

add_temp_log()

void add_temp_log

(

int

min_severity

)

Add a log handler to receive messages during startup (before the real logs are initialized).

change_callback_log_severity()

void change_callback_log_severity	(	int	loglevelMin,
		int	loglevelMax,
		log_callback	cb
	)

Adjust the configured severity of any logs whose callback function is cb.

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close_temp_logs()

void close_temp_logs

(

void

)

Close any log handlers added by add_temp_log() or marked by mark_logs_temp().

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flush_log_messages_from_startup()

void flush_log_messages_from_startup

(

void

)

Flush all the messages we stored from startup while waiting for log initialization.

flush_pending_log_callbacks()

void flush_pending_log_callbacks

(

void

)

If there are any log messages that were generated with LD_NOCB waiting to be sent to callback-based loggers, send them now.

get_min_log_level()

int get_min_log_level

(

void

)

Return the least severe log level that any current log is interested in.

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init_logging()

void init_logging

(

int

disable_startup_queue

)

Initialize the global logging facility

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log_fn_()

void log_fn_	(	int	severity,
		log_domain_mask_t	domain,
		const char *	fn,
		const char *	format,
			...
	)

Implementation of the log_fn backend, used when we have variadic macros. All arguments are as for log_fn, except for fn, which is the name of the calling functions.

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log_level_to_string()

const char* log_level_to_string

(

int

level

)

Return the string equivalent of a given log level.

log_message_is_interesting()

int log_message_is_interesting	(	int	severity,
		log_domain_mask_t	domain
	)

Return true if some of the running logs might be interested in a log message of the given severity in the given domains. If this function returns true, the log message might be ignored anyway, but if it returns false, it is definitely_ safe not to log the message.

log_set_application_name()

void log_set_application_name

(

const char *

name

)

Set the "application name" for the logs to name: we'll use this name in the message we write when starting up, and at the start of each new log.

Tor uses this string to write the version number to the log file.

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logs_free_all()

void logs_free_all

(

void

)

Close all open log files, and free other static memory.

logs_set_domain_logging()

void logs_set_domain_logging

(

int

enabled

)

Set whether we report logging domains as a part of our log messages.

logs_set_pending_callback_callback()

void logs_set_pending_callback_callback

(

pending_callback_callback

cb

)

Register "cb" as the callback to call when there are new pending log callbacks to be flushed with flush_pending_log_callbacks().

Note that this callback, if present, can be invoked from any thread.

This callback must not log.

It is intentional that this function contains the name "callback" twice: it sets a "callback" to be called on the condition that there is a "pending callback".

mark_logs_temp()

void mark_logs_temp

(

void

)

Configure all log handles to be closed by close_temp_logs().

MOCK_IMPL()

MOCK_IMPL	(	STATIC	void,
		logv	,
		(int severity, log_domain_mask_t domain, const char *funcname, const char *suffix, const char *format, va_list ap)
	)

Helper: sends a message to the appropriate logfiles, at loglevel severity. If provided, funcname is prepended to the message. The actual message is derived as from tor_snprintf(format,ap).

parse_log_level()

int parse_log_level

(

const char *

level

)

If level is a valid log severity, return the corresponding numeric value. Otherwise, return -1.

parse_log_severity_config()

int parse_log_severity_config	(	const char **	cfg_ptr,
		log_severity_list_t *	severity_out
	)

Parse a log severity pattern in *cfg_ptr. Advance cfg_ptr after the end of the severityPattern. Set the value of severity_out to the parsed pattern. Return 0 on success, -1 on failure.

The syntax for a SeverityPattern is:

  SeverityPattern = *(DomainSeverity SP)* DomainSeverity
  DomainSeverity = (DomainList SP)? SeverityRange
  SeverityRange = MinSeverity ("-" MaxSeverity )?
  DomainList = "[" (SP? DomainSpec SP? ",") SP? DomainSpec "]"
  DomainSpec = "*" | Domain | "~" Domain

A missing MaxSeverity defaults to ERR. Severities and domains are case-insensitive. "~" indicates negation for a domain; negation happens last inside a DomainList. Only one SeverityRange without a DomainList is allowed per line.

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rollback_log_changes()

void rollback_log_changes

(

void

)

Make all currently temporary logs (set to be closed by close_temp_logs) live again, and close all non-temporary logs.

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set_log_severity_config()

void set_log_severity_config	(	int	loglevelMin,
		int	loglevelMax,
		log_severity_list_t *	severity_out
	)

Adjust a log severity configuration in severity_out to contain every domain between loglevelMin and loglevelMax, inclusive.

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set_log_time_granularity()

void set_log_time_granularity

(

int

granularity_msec

)

Define log time granularity for all logs to be granularity_msec milliseconds.

switch_logs_debug()

void switch_logs_debug

(

void

)

Switch all logs to output at most verbose level.

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tor_log()

void tor_log	(	int	severity,
		log_domain_mask_t	domain,
		const char *	format,
			...
	)

Output a message to the log. It gets logged to all logfiles that care about messages with severity in domain. The content is formatted printf-style based on format and extra arguments.

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tor_log_err_sigsafe()

void tor_log_err_sigsafe	(	const char *	m,
			...
	)

Given a list of string arguments ending with a NULL, writes them to our logs and to stderr (if possible). This function is safe to call from within a signal handler.

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tor_log_get_logfile_names()

void tor_log_get_logfile_names

(

smartlist_t *

out

)

Add to out a copy of every currently configured log file name. Used to enable access to these filenames with the sandbox code.

tor_log_get_sigsafe_err_fds()

int tor_log_get_sigsafe_err_fds

(

const int **

out

)

Set *out to a pointer to an array of the fds to log errors to from inside a signal handler. Return the number of elements in the array.

tor_log_string()

void tor_log_string	(	int	severity,
		log_domain_mask_t	domain,
		const char *	function,
		const char *	string
	)

As tor_log, but takes an optional function name, and does not treat its string as a printf format.

For use by Rust integration.

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tor_log_update_sigsafe_err_fds()

void tor_log_update_sigsafe_err_fds

(

void

)

Function to call whenever the list of logs changes to get ready to log from signal handlers.

truncate_logs()

void truncate_logs

(

void

)

Truncate all the log files.

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Variable Documentation

log_global_min_severity_

int log_global_min_severity_ = LOG_NOTICE

What's the lowest log level anybody cares about? Checking this lets us bail out early from log_debug if we aren't debugging.

LOG_WARN_

const int LOG_WARN_ = LOG_WARN

Defining compile-time constants for Tor log levels (used by the Rust log wrapper at src/rust/tor_log)