mysql5/mysql-5.7.27/libmysql/mysql_trace.c

216 lines
6.2 KiB
C

/* Copyright (c) 2012, 2013, Oracle and/or its affiliates. All rights reserved.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 of the License.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */
/**
@file
=============================================
Client-side protocol tracing infrastructure
=============================================
If a plugin of type MYSQL_CLIENT_TRACE_PLUGIN is loaded into
libmysql and its instance is pointed by the global trace_plugin
pointer, this plugin is notified of various protocol trace events.
See include/mysql/plugin_trace.h for documentation of trace plugin
methods and the list of possible trace events.
These trace events are generated with MYSQL_TRACE() macro put in
relevant places in libmysql code. The macro calls mysql_trace_trace()
function defined here. This function calls trace plugin's
trace_event() method, if it is defined.
For each traced connection, the state is kept in st_mysql_trace_info
structure (see mysql_trace.h).
To correctly interpret each trace event, trace plugin is informed
of the current protocol stage (see include/mysql/plugin_trace.h for
list of stages). The current protocol stage is part of the
connection tracing state. It is updated with MYSQL_TRACE_STAGE()
hooks within libmysql code.
*/
#include <my_global.h>
#include "mysql.h"
#include "mysql_trace.h"
/*
Definition of the global trace_plugin pointer - see plugin_trace.h
for declaration and description.
*/
struct st_mysql_client_plugin_TRACE *trace_plugin= NULL;
/*
Macros for manipulating trace_info structure.
*/
#define GET_DATA(TI) (TI)->trace_plugin_data
#define SET_DATA(TI,D) GET_DATA(TI) = (D)
#define GET_STAGE(TI) (TI)->stage
#define TEST_STAGE(TI,X) (GET_STAGE(TI) == PROTOCOL_STAGE_ ## X)
#define SET_STAGE(TI,X) GET_STAGE(TI) = PROTOCOL_STAGE_ ## X
/**
Initialize tracing in a given connection.
This function is called from MYSQL_TRACE_STAGE() when the initial
CONNECTING stage is reported. It allocates and initializes trace_info
structure which is then attached to the connection handle.
*/
void mysql_trace_start(struct st_mysql *m)
{
struct st_mysql_trace_info *trace_info;
trace_info= my_malloc(PSI_NOT_INSTRUMENTED,
sizeof(struct st_mysql_trace_info),
MYF(MY_ZEROFILL));
if (!trace_info)
{
/*
Note: in this case trace_data of the connection will
remain NULL and thus tracing will be disabled.
*/
return;
}
/*
This function should be called only when a trace plugin
is loaded and thus trace_plugin pointer is not NULL. This
is handled in MYSQL_TRACE_STAGE() macro (mysql_trace.h).
*/
DBUG_ASSERT(trace_plugin);
trace_info->plugin= trace_plugin;
trace_info->stage= PROTOCOL_STAGE_CONNECTING;
/*
Call plugin's tracing_start() method, if defined.
*/
if (trace_info->plugin->tracing_start)
{
trace_info->trace_plugin_data=
trace_info->plugin->tracing_start(
trace_info->plugin,
m, PROTOCOL_STAGE_CONNECTING);
}
else
{
trace_info->trace_plugin_data= NULL;
}
/* Store trace_info in the connection handle. */
TRACE_DATA(m)= trace_info;
}
/**
Report a protocol trace event to trace plugin.
Calls plugin's trace_event() method, if it is defined, passing to
it the event, the current protocol stage and event arguments (if any).
Terminates tracing of the connection when appropriate.
@param m MYSQL connection handle
@param ev trace event to be reported
@param args trace event arguments
*/
void mysql_trace_trace(struct st_mysql *m,
enum trace_event ev,
struct st_trace_event_args args)
{
struct st_mysql_trace_info *trace_info= TRACE_DATA(m);
struct st_mysql_client_plugin_TRACE *plugin= trace_info ? trace_info->plugin : NULL;
int quit_tracing= 0;
/*
If trace_info is NULL then this connection is not traced and this
function should not be called - this is handled inside MYSQL_TRACE()
macro.
*/
DBUG_ASSERT(trace_info);
/* Call plugin's trace_event() method if defined */
if (plugin->trace_event)
{
/*
Temporarily disable tracing while executing plugin's method
by setting trace data pointer to NULL. Also, set reconnect
flag to 0 in case plugin executes any queries.
*/
my_bool saved_reconnect_flag= m->reconnect;
TRACE_DATA(m)= NULL;
m->reconnect= 0;
quit_tracing= plugin->trace_event(plugin, GET_DATA(trace_info), m,
GET_STAGE(trace_info), ev, args);
m->reconnect= saved_reconnect_flag;
TRACE_DATA(m)= trace_info;
}
/* Stop tracing if requested or end of connection. */
if (quit_tracing
|| TEST_STAGE(trace_info, DISCONNECTED)
|| TRACE_EVENT_DISCONNECTED == ev)
{
/* Note: this disables further tracing */
TRACE_DATA(m)= NULL;
if (plugin->tracing_stop)
plugin->tracing_stop(plugin, m, GET_DATA(trace_info));
my_free(trace_info);
}
}
#ifndef DBUG_OFF
/*
These functions are declared in plugin_trace.h.
Consult documentation of *_LIST() macros (plugin_trace.h) to see how
switch() bodies are constructed with the *_get_name() macros.
*/
#define protocol_stage_get_name(X) case PROTOCOL_STAGE_ ## X: return #X;
const char* protocol_stage_name(enum protocol_stage stage)
{
switch(stage)
{
PROTOCOL_STAGE_LIST(get_name)
default: return "<unknown stage>";
}
}
#define trace_event_get_name(X) case TRACE_EVENT_ ## X: return #X;
const char* trace_event_name(enum trace_event ev)
{
switch(ev)
{
TRACE_EVENT_LIST(get_name)
default: return "<unknown event>";
}
}
#endif