log.cc File Reference

logging of commands More...

#include "sql/log.h"
#include "my_config.h"
#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "m_string.h"
#include "my_sys.h"
#include "mysql/components/services/log_builtins.h"
#include "mysql/components/services/log_shared.h"
#include "mysql/psi/mysql_rwlock.h"
#include "mysql/strings/int2str.h"
#include "mysql_time.h"
#include "nulls.h"
#include "server_component/log_sink_buffer.h"
#include "sql_string.h"
#include "strxnmov.h"
#include <sys/time.h>
#include <unistd.h>
#include <algorithm>
#include <atomic>
#include <new>
#include <sstream>
#include <string>
#include <utility>
#include "lex_string.h"
#include "my_base.h"
#include "my_dbug.h"
#include "my_dir.h"
#include "my_double2ulonglong.h"
#include "my_time.h"
#include "mysql/plugin.h"
#include "mysql/psi/mysql_file.h"
#include "mysql/service_my_plugin_log.h"
#include "mysql/service_mysql_alloc.h"
#include "mysql/strings/m_ctype.h"
#include "mysql_version.h"
#include "mysqld_error.h"
#include "mysys_err.h"
#include "sql/auth/auth_acls.h"
#include "sql/auth/sql_security_ctx.h"
#include "sql/current_thd.h"
#include "sql/debug_sync.h"
#include "sql/derror.h"
#include "sql/discrete_interval.h"
#include "sql/error_handler.h"
#include "sql/field.h"
#include "sql/handler.h"
#include "sql/mysqld.h"
#include "sql/protocol_classic.h"
#include "sql/psi_memory_key.h"
#include "sql/query_options.h"
#include "sql/sql_audit.h"
#include "sql/sql_base.h"
#include "sql/sql_class.h"
#include "sql/sql_error.h"
#include "sql/sql_lex.h"
#include "sql/sql_parse.h"
#include "sql/sql_plugin_ref.h"
#include "sql/sql_time.h"
#include "sql/system_variables.h"
#include "sql/table.h"
#include "string_with_len.h"
#include "strmake.h"
#include "strxmov.h"
#include "thr_lock.h"
#include "thr_mutex.h"
#include "sql/server_component/log_builtins_imp.h"

Classes
class	Query_log_table_intact
class	Silence_log_table_errors
	Silence all errors and warnings reported when performing a write to a log table. More...
class	File_query_log
class	Log_to_file_event_handler
	Class responsible for file based logging. More...

Enumerations
enum	enum_slow_query_log_table_field {   SQLT_FIELD_START_TIME = 0 , SQLT_FIELD_USER_HOST , SQLT_FIELD_QUERY_TIME , SQLT_FIELD_LOCK_TIME ,   SQLT_FIELD_ROWS_SENT , SQLT_FIELD_ROWS_EXAMINED , SQLT_FIELD_DATABASE , SQLT_FIELD_LAST_INSERT_ID ,   SQLT_FIELD_INSERT_ID , SQLT_FIELD_SERVER_ID , SQLT_FIELD_SQL_TEXT , SQLT_FIELD_THREAD_ID ,   SQLT_FIELD_COUNT }
enum	enum_general_log_table_field {   GLT_FIELD_EVENT_TIME = 0 , GLT_FIELD_USER_HOST , GLT_FIELD_THREAD_ID , GLT_FIELD_SERVER_ID ,   GLT_FIELD_COMMAND_TYPE , GLT_FIELD_ARGUMENT , GLT_FIELD_COUNT }

Functions
static void	ull2timeval (ulonglong utime, my_timeval *tv)
bool	is_valid_log_name (const char *name, size_t len)
	Check given log name against certain blacklisted names/extensions. More...
static File	mysql_file_real_name_reopen (File file, PSI_file_key log_file_key, int open_flags, const char *opened_file_name, char *real_file_name)
	Get the real log file name, and possibly reopen file. More...
static bool	log_command (THD *thd, enum_server_command command)
	Check if a given command should be logged to the general log. More...
char *	make_query_log_name (char *buff, enum_log_table_type log_type)
	Create the name of the query log specified. More...
bool	log_slow_applicable (THD *thd)
	Check whether we need to write the current statement (or its rewritten version if it exists) to the slow query log. More...
void	log_slow_do (THD *thd)
	Unconditionally writes the current statement (or its rewritten version if it exists) to the slow query log. More...
void	log_slow_statement (THD *thd)
	Check whether we need to write the current statement to the slow query log. More...
static bool	slow_log_write (THD *thd, const char *query, size_t query_length, bool aggregate, ulonglong time_usec, ulonglong lock_usec)
Slow_log_throttle log_throttle_qni &	opt_log_throttle_queries_not_using_indexes (s) suppressed."
void	discard_error_log_messages ()
	Discard all buffered messages and deallocate buffer without printing anything. More...
void	flush_error_log_messages ()
	We buffer all error log messages that have been printed before the error log has been opened. More...
bool	init_error_log ()
	Initialize structures (e.g. More...
bool	open_error_log (const char *filename, bool get_lock)
	Open the error log and redirect stderr and optionally stdout to the error log file. More...
void	destroy_error_log ()
	Free any error log resources. More...
bool	reopen_error_log ()
	Flush any pending data to disk and reopen the error log. More...
void	log_write_errstream (const char *buffer, size_t length)
	Interim helper: write to the default error stream. More...
my_thread_id	log_get_thread_id (THD *thd)
	A helper that we can stubify so we don't have to pull all of THD into the unit tests. More...
int	log_vmessage (int log_type, va_list fili)
	Variadic convenience function for logging. More...
void	error_log_print (enum loglevel level, uint ecode, va_list args)
	Prints a printf style message to the error log. More...
int	log_message (int log_type,...)
	Variadic convenience function for logging. More...
int	my_plugin_log_message (MYSQL_PLUGIN *plugin_ptr, plugin_log_level level, const char *format,...)

Variables
static const TABLE_FIELD_TYPE	slow_query_log_table_fields [SQLT_FIELD_COUNT]
static const TABLE_FIELD_DEF	slow_query_log_table_def
static const TABLE_FIELD_TYPE	general_log_table_fields [GLT_FIELD_COUNT]
static const TABLE_FIELD_DEF	general_log_table_def
static Query_log_table_intact	log_table_intact
	In case of an error, a message is printed to the error log. More...
Query_logger	query_logger
static bool	error_log_initialized = false
static mysql_mutex_t	LOCK_error_log
static const char *	error_log_file = nullptr

Detailed Description

logging of commands

Enumeration Type Documentation

enum_general_log_table_field

enum enum_general_log_table_field

Enumerator
GLT_FIELD_EVENT_TIME
GLT_FIELD_USER_HOST
GLT_FIELD_THREAD_ID
GLT_FIELD_SERVER_ID
GLT_FIELD_COMMAND_TYPE
GLT_FIELD_ARGUMENT
GLT_FIELD_COUNT

enum_slow_query_log_table_field

enum enum_slow_query_log_table_field

Enumerator
SQLT_FIELD_START_TIME
SQLT_FIELD_USER_HOST
SQLT_FIELD_QUERY_TIME
SQLT_FIELD_LOCK_TIME
SQLT_FIELD_ROWS_SENT
SQLT_FIELD_ROWS_EXAMINED
SQLT_FIELD_DATABASE
SQLT_FIELD_LAST_INSERT_ID
SQLT_FIELD_INSERT_ID
SQLT_FIELD_SERVER_ID
SQLT_FIELD_SQL_TEXT
SQLT_FIELD_THREAD_ID
SQLT_FIELD_COUNT

Function Documentation

destroy_error_log()

void destroy_error_log

(

)

Free any error log resources.

Note

This function accesses shared resources without protection, so it should only be called while the server is running single-threaded.

The error log can still be used after this function is called, but that should only be done single-threaded. All buffered messages should be flushed before calling this function.

discard_error_log_messages()

void discard_error_log_messages

(

)

Discard all buffered messages and deallocate buffer without printing anything.

Needed when terminating launching process after daemon has started. At this point we may have messages in the error log, but we don't want to show them to stderr (the daemon will output them in its error log).

error_log_print()

void error_log_print	(	enum loglevel	level,
		uint	ecode,
		va_list	args
	)

Prints a printf style message to the error log.

A thin wrapper around log_message() for local_message_hook, Table_check_intact::report_error, and others.

Parameters

level	The level of the msg significance
ecode	Error code of the error message.
args	va_list list of arguments for the message

flush_error_log_messages()

void flush_error_log_messages

(

)

We buffer all error log messages that have been printed before the error log has been opened.

This allows us to write them to the correct file once the error log has been opened.

This function will explicitly flush buffered messages to stderr. It is only needed in cases where open_error_log() is not called as it otherwise will be done there.

This function also turns buffering off (there is no way to turn buffering back on).

init_error_log()

bool init_error_log

(

)

Initialize structures (e.g.

mutex) needed by the error log.

Note

This function accesses shared resources without protection, so it should only be called while the server is running single-threaded.

The error log can still be used before this function is called, but that should only be done single-threaded.

Return values

true	an error occurred
false	basic error logging is now available in multi-threaded mode

is_valid_log_name()

bool is_valid_log_name	(	const char *	name,
		size_t	len
	)

Check given log name against certain blacklisted names/extensions.

Parameters

name	Log name to check
len	Length of log name

Returns

true if name is valid, false otherwise.

log_command()

static bool log_command ( THD *  thd, enum_server_command  command  )

static

Check if a given command should be logged to the general log.

Parameters

thd	Thread handle
command	SQL command

Returns

true if command should be logged, false otherwise.

log_get_thread_id()

my_thread_id log_get_thread_id

(

THD *

thd

)

A helper that we can stubify so we don't have to pull all of THD into the unit tests.

Parameters

thd

a thd

Return values

its

thread-ID

log_message()

int log_message	(	int	log_type,
			...
	)

Variadic convenience function for logging.

This fills in the array that is used by the filter and log-writer services. Where missing, timestamp, priority, and thread-ID (if any) are added. Log item source services, log item filters, and log item writers are called.

see log_vmessage() for more information.

Parameters

log_type	what log should this go to?
...	fields: LOG_ITEM_* tag, [[key], value]

Return values

int	return value of log_vmessage()

log_slow_applicable()

bool log_slow_applicable

(

THD *

thd

)

Check whether we need to write the current statement (or its rewritten version if it exists) to the slow query log.

As a side-effect, a digest of suppressed statements may be written.

Parameters

thd	thread handle

Return values

true	statement needs to be logged
false	statement does not need to be logged

log_slow_do()

void log_slow_do

(

THD *

thd

)

Unconditionally writes the current statement (or its rewritten version if it exists) to the slow query log.

Parameters

thd	thread handle

log_slow_statement()

void log_slow_statement

(

THD *

thd

)

Check whether we need to write the current statement to the slow query log.

If so, do so. This is a wrapper for the two functions above; most callers should use this wrapper. Only use the above functions directly if you have expensive rewriting that you only need to do if the query actually needs to be logged (e.g. SP variables / NAME_CONST substitution when executing a PROCEDURE). A digest of suppressed statements may be logged instead of the current statement.

Parameters

thd	thread handle

log_vmessage()

int log_vmessage	(	int	log_type,
		va_list	fili
	)

Variadic convenience function for logging.

Write a message to a log (for now just used for error log).

This fills in the array that is used by the filter and log-writer services. Where missing, timestamp, priority, and thread-ID (if any) are added. Log item source services, log item filters, and log item writers are called.

For convenience, any number of fields may be added:

• "well-known" field types require a type tag and the payload: LOG_ITEM_LOG_LABEL, "ohai"
• "generic" field types require a type tag, a key (C-string), and the payload: LOG_ITEM_GEN_FLOAT, "myPi", 3.1415926927

Newer items (further to the right/bottom) overwrite older ones (further to the left/top).

If a message is given, it must be the last tag in the argument list. The message may be given verbatim as a C format string, followed by its arguments:

LOG_ITEM_LOG_MESSAGE, "format string %s %d abc", "arg1", 12345

To avoid substitutions, use

LOG_ITEM_LOG_VERBATIM, "message from other subsys containing %user input"

Alternatively, an error code may be specified – the corresponding error message will be looked up and inserted –, followed by any arguments required by the error message:

LOG_ITEM_LOG_LOOKUP, ER_CANT_SET_DATA_DIR, filename, errno, strerror(errno)

If no message is to be included (this should never be the case for the error log), LOG_ITEM_END may be used instead to terminate the list.

Parameters

log_type	what log should this go to?
fili	field list: LOG_ITEM_* tag, [[key], value]

Return values

int	return value of log_line_submit()

log_write_errstream()

void log_write_errstream	(	const char *	buffer,
		size_t	length
	)

Interim helper: write to the default error stream.

Parameters

buffer	buffer containing serialized error message
length	number of bytes in buffer

make_query_log_name()

char * make_query_log_name	(	char *	buff,
		enum_log_table_type	log_type
	)

Create the name of the query log specified.

This method forms a new path + file name for the log specified.

Parameters

[in]	buff	Location for building new string.
[in]	log_type	QUERY_LOG_SLOW or QUERY_LOG_GENERAL

Returns

Pointer to new string containing the name.

my_plugin_log_message()

int my_plugin_log_message	(	MYSQL_PLUGIN *	plugin_ptr,
		plugin_log_level	level,
		const char *	format,
			...
	)

mysql_file_real_name_reopen()

static File mysql_file_real_name_reopen ( File  file, PSI_file_key  log_file_key, int  open_flags, const char *  opened_file_name, char *  real_file_name  )

static

Get the real log file name, and possibly reopen file.

The implementation is platform dependent due to differences in how this is supported:

On Windows, we get the actual path based on the file descriptor. This path is copied into the supplied buffer. The 'file' parameter is returned without re-opening.

On other platforms, we use realpath() to get the path with symbolic links expanded. Then, we close the file, and reopen the real path using the O_NOFOLLOW flag. This will reject following symbolic links.

Parameters

	file	File descriptor.
	log_file_key	Key for P_S instrumentation.
	open_flags	Flags to use for opening the file.
	opened_file_name	Name of the open fd.
[out]	real_file_name	Buffer for actual name of the fd.

Returns

file descriptor to open file with 'real_file_name', or '-1' in case of errors.

open_error_log()

bool open_error_log	(	const char *	filename,
		bool	get_lock
	)

Open the error log and redirect stderr and optionally stdout to the error log file.

The streams are reopened only for appending (writing at end of file).

Note

On error, my_error() is not called here. So, caller of this function should call my_error() to keep the protocol.

This function also writes any error log messages that have been buffered by calling flush_error_log_messages().

Parameters

filename	Name of error log file
get_lock	Should we acquire LOCK_error_log?

Make sure, file is writable if it exists. If file does not exists then make sure directory path exists and it is writable.

opt_log_throttle_queries_not_using_indexes()

Slow_log_throttle log_throttle_qni & opt_log_throttle_queries_not_using_indexes

(

s

)

reopen_error_log()

bool reopen_error_log

(

)

Flush any pending data to disk and reopen the error log.

slow_log_write()

static bool slow_log_write ( THD *  thd, const char *  query, size_t  query_length, bool  aggregate, ulonglong  time_usec, ulonglong  lock_usec  )

static

ull2timeval()

static void ull2timeval ( ulonglong  utime, my_timeval *  tv  )

static

Variable Documentation

error_log_file

const char* error_log_file = nullptr

static

error_log_initialized

bool error_log_initialized = false

static

general_log_table_def

const TABLE_FIELD_DEF general_log_table_def

static

Initial value:

= {GLT_FIELD_COUNT,
                                                      general_log_table_fields}

general_log_table_fields

const TABLE_FIELD_TYPE general_log_table_fields[GLT_FIELD_COUNT]

static

Initial value:

= {
    {{STRING_WITH_LEN("event_time")},
     {STRING_WITH_LEN("timestamp(6)")},
     {nullptr, 0}},
    {{STRING_WITH_LEN("user_host")},
     {STRING_WITH_LEN("mediumtext")},
     {STRING_WITH_LEN("utf8mb3")}},
    {{STRING_WITH_LEN("thread_id")},
     {STRING_WITH_LEN("bigint unsigned")},
     {nullptr, 0}},
    {{STRING_WITH_LEN("server_id")},
     {STRING_WITH_LEN("int unsigned")},
     {nullptr, 0}},
    {{STRING_WITH_LEN("command_type")},
     {STRING_WITH_LEN("varchar(64)")},
     {STRING_WITH_LEN("utf8mb3")}},
    {{STRING_WITH_LEN("argument")},
     {STRING_WITH_LEN("mediumblob")},
     {nullptr, 0}}}

LOCK_error_log

mysql_mutex_t LOCK_error_log

static

log_table_intact

Query_log_table_intact log_table_intact

static

In case of an error, a message is printed to the error log.

query_logger

Query_logger query_logger

slow_query_log_table_def

const TABLE_FIELD_DEF slow_query_log_table_def

static

Initial value:

= {
    SQLT_FIELD_COUNT, slow_query_log_table_fields}

slow_query_log_table_fields

const TABLE_FIELD_TYPE slow_query_log_table_fields[SQLT_FIELD_COUNT]

static