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protocol.cc
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/* Copyright (c) 2000, 2012, Oracle and/or its affiliates.
Copyright (c) 2008, 2020, MariaDB Corporation.
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 02110-1335 USA */
/**
@file
Low level functions for storing data to be send to the MySQL client.
The actual communction is handled by the net_xxx functions in net_serv.cc
*/
#ifdef USE_PRAGMA_IMPLEMENTATION
#pragma implementation // gcc: Class implementation
#endif
#include "mariadb.h"
#include "sql_priv.h"
#include "protocol.h"
#include "sql_class.h" // THD
#include <stdarg.h>
static const unsigned int PACKET_BUFFER_EXTRA_ALLOC= 1024;
#ifndef EMBEDDED_LIBRARY
static bool write_eof_packet(THD *, NET *, uint, uint);
#endif
CHARSET_INFO *Protocol::character_set_results() const
{
return thd->variables.character_set_results;
}
#ifndef EMBEDDED_LIBRARY
bool Protocol::net_store_data(const uchar *from, size_t length)
#else
bool Protocol_binary::net_store_data(const uchar *from, size_t length)
#endif
{
ulong packet_length=packet->length();
/*
The +9 comes from that strings of length longer than 16M require
9 bytes to be stored (see net_store_length).
*/
if (packet_length+9+length > packet->alloced_length() &&
packet->realloc(packet_length+9+length))
return 1;
uchar *to= net_store_length((uchar*) packet->ptr()+packet_length, length);
if (length)
memcpy(to,from,length);
packet->length((uint) (to+length-(uchar*) packet->ptr()));
return 0;
}
/*
net_store_data_cs() - extended version with character set conversion.
It is optimized for short strings whose length after
conversion is garanteed to be less than 251, which accupies
exactly one byte to store length. It allows not to use
the "convert" member as a temporary buffer, conversion
is done directly to the "packet" member.
The limit 251 is good enough to optimize send_result_set_metadata()
because column, table, database names fit into this limit.
*/
#ifndef EMBEDDED_LIBRARY
bool Protocol::net_store_data_cs(const uchar *from, size_t length,
CHARSET_INFO *from_cs, CHARSET_INFO *to_cs)
#else
bool Protocol_binary::net_store_data_cs(const uchar *from, size_t length,
CHARSET_INFO *from_cs, CHARSET_INFO *to_cs)
#endif
{
uint dummy_errors;
/* Calculate maxumum possible result length */
size_t conv_length= to_cs->mbmaxlen * length / from_cs->mbminlen;
if (conv_length > 250)
{
/*
For strings with conv_length greater than 250 bytes
we don't know how many bytes we will need to store length: one or two,
because we don't know result length until conversion is done.
For example, when converting from utf8 (mbmaxlen=3) to latin1,
conv_length=300 means that the result length can vary between 100 to 300.
length=100 needs one byte, length=300 needs to bytes.
Thus conversion directly to "packet" is not worthy.
Let's use "convert" as a temporary buffer.
*/
return (convert->copy((const char*) from, length, from_cs,
to_cs, &dummy_errors) ||
net_store_data((const uchar*) convert->ptr(), convert->length()));
}
size_t packet_length= packet->length();
size_t new_length= packet_length + conv_length + 1;
if (new_length > packet->alloced_length() && packet->realloc(new_length))
return 1;
char *length_pos= (char*) packet->ptr() + packet_length;
char *to= length_pos + 1;
to+= copy_and_convert(to, conv_length, to_cs,
(const char*) from, length, from_cs, &dummy_errors);
net_store_length((uchar*) length_pos, to - length_pos - 1);
packet->length((uint) (to - packet->ptr()));
return 0;
}
/**
Send a error string to client.
Design note:
net_printf_error and net_send_error are low-level functions
that shall be used only when a new connection is being
established or at server startup.
For SIGNAL/RESIGNAL and GET DIAGNOSTICS functionality it's
critical that every error that can be intercepted is issued in one
place only, my_message_sql.
@param thd Thread handler
@param sql_errno The error code to send
@param err A pointer to the error message
@return
@retval FALSE The message was sent to the client
@retval TRUE An error occurred and the message wasn't sent properly
*/
bool Protocol::net_send_error(THD *thd, uint sql_errno, const char *err,
const char* sqlstate)
{
bool error;
DBUG_ENTER("Protocol::net_send_error");
DBUG_ASSERT(!thd->spcont);
DBUG_ASSERT(sql_errno);
DBUG_ASSERT(err);
DBUG_PRINT("enter",("sql_errno: %d err: %s", sql_errno, err));
if (sqlstate == NULL)
sqlstate= mysql_errno_to_sqlstate(sql_errno);
/*
It's one case when we can push an error even though there
is an OK or EOF already.
*/
thd->get_stmt_da()->set_overwrite_status(true);
/* Abort multi-result sets */
thd->server_status&= ~SERVER_MORE_RESULTS_EXISTS;
error= net_send_error_packet(thd, sql_errno, err, sqlstate);
thd->get_stmt_da()->set_overwrite_status(false);
DBUG_RETURN(error);
}
/**
Return ok to the client.
The ok packet has the following structure:
- 0 : Marker (1 byte)
- affected_rows : Stored in 1-9 bytes
- id : Stored in 1-9 bytes
- server_status : Copy of thd->server_status; Can be used by client
to check if we are inside an transaction.
New in 4.0 protocol
- warning_count : Stored in 2 bytes; New in 4.1 protocol
- message : Stored as packed length (1-9 bytes) + message.
Is not stored if no message.
@param thd Thread handler
@param server_status The server status
@param statement_warn_count Total number of warnings
@param affected_rows Number of rows changed by statement
@param id Auto_increment id for first row (if used)
@param message Message to send to the client (Used by mysql_status)
@param is_eof this called instead of old EOF packet
@return
@retval FALSE The message was successfully sent
@retval TRUE An error occurred and the messages wasn't sent properly
*/
#ifndef EMBEDDED_LIBRARY
bool
Protocol::net_send_ok(THD *thd,
uint server_status, uint statement_warn_count,
ulonglong affected_rows, ulonglong id,
const char *message, bool is_eof)
{
NET *net= &thd->net;
StringBuffer<MYSQL_ERRMSG_SIZE + 10> store;
bool error= FALSE;
DBUG_ENTER("Protocol::net_send_ok");
if (! net->vio) // hack for re-parsing queries
{
DBUG_PRINT("info", ("vio present: NO"));
DBUG_RETURN(FALSE);
}
/*
OK send instead of EOF still require 0xFE header, but OK packet content.
*/
if (is_eof)
{
DBUG_ASSERT(thd->client_capabilities & CLIENT_DEPRECATE_EOF);
store.q_append((char)254);
}
else
store.q_append('\0');
/* affected rows */
store.q_net_store_length(affected_rows);
/* last insert id */
store.q_net_store_length(id);
/* if client has not session tracking capability, don't send state change flag*/
if (!(thd->client_capabilities & CLIENT_SESSION_TRACK)) {
server_status &= ~SERVER_SESSION_STATE_CHANGED;
}
if (thd->client_capabilities & CLIENT_PROTOCOL_41)
{
DBUG_PRINT("info",
("affected_rows: %lu id: %lu status: %u warning_count: %u",
(ulong) affected_rows,
(ulong) id,
(uint) (server_status & 0xffff),
(uint) statement_warn_count));
store.q_append2b(server_status);
/* We can only return up to 65535 warnings in two bytes */
uint tmp= MY_MIN(statement_warn_count, 65535);
store.q_append2b(tmp);
}
else if (net->return_status) // For 4.0 protocol
{
store.q_append2b(server_status);
}
thd->get_stmt_da()->set_overwrite_status(true);
if ((server_status & SERVER_SESSION_STATE_CHANGED) || (message && message[0]))
{
DBUG_ASSERT(safe_strlen(message) <= MYSQL_ERRMSG_SIZE);
store.q_net_store_data((uchar*) safe_str(message), safe_strlen(message));
}
if (unlikely(server_status & SERVER_SESSION_STATE_CHANGED))
{
store.set_charset(thd->variables.collation_database);
thd->session_tracker.store(thd, &store);
thd->server_status&= ~SERVER_SESSION_STATE_CHANGED;
}
DBUG_ASSERT(store.length() <= MAX_PACKET_LENGTH);
error= my_net_write(net, (const unsigned char*)store.ptr(), store.length());
if (likely(!error))
error= net_flush(net);
thd->get_stmt_da()->set_overwrite_status(false);
DBUG_PRINT("info", ("OK sent, so no more error sending allowed"));
DBUG_RETURN(error);
}
static uchar eof_buff[1]= { (uchar) 254 }; /* Marker for end of fields */
/**
Send eof (= end of result set) to the client.
The eof packet has the following structure:
- 254 : Marker (1 byte)
- warning_count : Stored in 2 bytes; New in 4.1 protocol
- status_flag : Stored in 2 bytes;
For flags like SERVER_MORE_RESULTS_EXISTS.
Note that the warning count will not be sent if 'no_flush' is set as
we don't want to report the warning count until all data is sent to the
client.
@param thd Thread handler
@param server_status The server status
@param statement_warn_count Total number of warnings
@return
@retval FALSE The message was successfully sent
@retval TRUE An error occurred and the message wasn't sent properly
*/
bool
Protocol::net_send_eof(THD *thd, uint server_status, uint statement_warn_count)
{
NET *net= &thd->net;
bool error= FALSE;
DBUG_ENTER("Protocol::net_send_eof");
DBUG_PRINT("enter", ("status: %u warn_count: %u",
server_status, statement_warn_count));
/*
Check if client understand new format packets (OK instead of EOF)
Normally end of statement reply is signaled by OK packet, but in case
of binlog dump request an EOF packet is sent instead. Also, old clients
expect EOF packet instead of OK
*/
if ((thd->client_capabilities & CLIENT_DEPRECATE_EOF) &&
(thd->get_command() != COM_BINLOG_DUMP ))
{
error= net_send_ok(thd, server_status, statement_warn_count, 0, 0, NULL,
true);
DBUG_RETURN(error);
}
/* Set to TRUE if no active vio, to work well in case of --init-file */
if (net->vio != 0)
{
thd->get_stmt_da()->set_overwrite_status(true);
error= write_eof_packet(thd, net, server_status, statement_warn_count);
if (likely(!error))
error= net_flush(net);
thd->get_stmt_da()->set_overwrite_status(false);
DBUG_PRINT("info", ("EOF sent, so no more error sending allowed"));
}
DBUG_RETURN(error);
}
/**
Format EOF packet according to the current protocol and
write it to the network output buffer.
@param thd The thread handler
@param net The network handler
@param server_status The server status
@param statement_warn_count The number of warnings
@return
@retval FALSE The message was sent successfully
@retval TRUE An error occurred and the messages wasn't sent properly
*/
static bool write_eof_packet(THD *thd, NET *net,
uint server_status,
uint statement_warn_count)
{
bool error;
if (thd->client_capabilities & CLIENT_PROTOCOL_41)
{
uchar buff[5];
/*
Don't send warn count during SP execution, as the warn_list
is cleared between substatements, and mysqltest gets confused
*/
uint tmp= MY_MIN(statement_warn_count, 65535);
buff[0]= 254;
int2store(buff+1, tmp);
/*
The following test should never be true, but it's better to do it
because if 'is_fatal_error' is set the server is not going to execute
other queries (see the if test in dispatch_command / COM_QUERY)
*/
if (unlikely(thd->is_fatal_error))
server_status&= ~SERVER_MORE_RESULTS_EXISTS;
int2store(buff + 3, server_status);
error= my_net_write(net, buff, 5);
}
else
error= my_net_write(net, eof_buff, 1);
return error;
}
/**
@param thd Thread handler
@param sql_errno The error code to send
@param err A pointer to the error message
@return
@retval FALSE The message was successfully sent
@retval TRUE An error occurred and the messages wasn't sent properly
*/
bool Protocol::net_send_error_packet(THD *thd, uint sql_errno, const char *err,
const char* sqlstate)
{
NET *net= &thd->net;
uint length;
/*
buff[]: sql_errno:2 + ('#':1 + SQLSTATE_LENGTH:5) + MYSQL_ERRMSG_SIZE:512
*/
uint error;
char converted_err[MYSQL_ERRMSG_SIZE];
char buff[2+1+SQLSTATE_LENGTH+MYSQL_ERRMSG_SIZE], *pos;
my_bool ret;
uint8 save_compress;
DBUG_ENTER("Protocol::send_error_packet");
if (net->vio == 0)
{
if (thd->bootstrap)
{
/* In bootstrap it's ok to print on stderr */
fprintf(stderr,"ERROR: %d %s\n",sql_errno,err);
}
DBUG_RETURN(FALSE);
}
int2store(buff,sql_errno);
pos= buff+2;
if (thd->client_capabilities & CLIENT_PROTOCOL_41)
{
/* The first # is to make the protocol backward compatible */
buff[2]= '#';
pos= strmov(buff+3, sqlstate);
}
convert_error_message(converted_err, sizeof(converted_err),
thd->variables.character_set_results,
err, strlen(err), system_charset_info, &error);
/* Converted error message is always null-terminated. */
length= (uint) (strmake(pos, converted_err, MYSQL_ERRMSG_SIZE - 1) - buff);
/*
Ensure that errors are not compressed. This is to ensure we can
detect out of bands error messages in the client
*/
if ((save_compress= net->compress))
net->compress= 2;
/*
Sometimes, we send errors "out-of-band", e.g ER_CONNECTION_KILLED
on an idle connection. The current protocol "sequence number" is 0,
however some client drivers would however always expect packets
coming from server to have seq_no > 0, due to missing awareness
of "out-of-band" operations. Make these clients happy.
*/
if (!net->pkt_nr &&
(sql_errno == ER_CONNECTION_KILLED || sql_errno == ER_SERVER_SHUTDOWN ||
sql_errno == ER_QUERY_INTERRUPTED))
{
net->pkt_nr= 1;
}
ret= net_write_command(net,(uchar) 255, (uchar*) "", 0, (uchar*) buff,
length);
net->compress= save_compress;
DBUG_RETURN(ret);
}
#endif /* EMBEDDED_LIBRARY */
/**
Faster net_store_length when we know that length is less than 65536.
We keep a separate version for that range because it's widely used in
libmysql.
uint is used as agrument type because of MySQL type conventions:
- uint for 0..65536
- ulong for 0..4294967296
- ulonglong for bigger numbers.
*/
static uchar *net_store_length_fast(uchar *packet, size_t length)
{
DBUG_ASSERT(length < UINT_MAX16);
if (length < 251)
{
*packet=(uchar) length;
return packet+1;
}
*packet++=252;
int2store(packet,(uint) length);
return packet+2;
}
/**
Send the status of the current statement execution over network.
@param thd in fact, carries two parameters, NET for the transport and
Diagnostics_area as the source of status information.
In MySQL, there are two types of SQL statements: those that return
a result set and those that return status information only.
If a statement returns a result set, it consists of 3 parts:
- result set meta-data
- variable number of result set rows (can be 0)
- followed and terminated by EOF or ERROR packet
Once the client has seen the meta-data information, it always
expects an EOF or ERROR to terminate the result set. If ERROR is
received, the result set rows are normally discarded (this is up
to the client implementation, libmysql at least does discard them).
EOF, on the contrary, means "successfully evaluated the entire
result set". Since we don't know how many rows belong to a result
set until it's evaluated, EOF/ERROR is the indicator of the end
of the row stream. Note, that we can not buffer result set rows
on the server -- there may be an arbitrary number of rows. But
we do buffer the last packet (EOF/ERROR) in the Diagnostics_area and
delay sending it till the very end of execution (here), to be able to
change EOF to an ERROR if commit failed or some other error occurred
during the last cleanup steps taken after execution.
A statement that does not return a result set doesn't send result
set meta-data either. Instead it returns one of:
- OK packet
- ERROR packet.
Similarly to the EOF/ERROR of the previous statement type, OK/ERROR
packet is "buffered" in the diagnostics area and sent to the client
in the end of statement.
@note This method defines a template, but delegates actual
sending of data to virtual Protocol::send_{ok,eof,error}. This
allows for implementation of protocols that "intercept" ok/eof/error
messages, and store them in memory, etc, instead of sending to
the client.
@pre The diagnostics area is assigned or disabled. It can not be empty
-- we assume that every SQL statement or COM_* command
generates OK, ERROR, or EOF status.
@post The status information is encoded to protocol format and sent to the
client.
@return We conventionally return void, since the only type of error
that can happen here is a NET (transport) error, and that one
will become visible when we attempt to read from the NET the
next command.
Diagnostics_area::is_sent is set for debugging purposes only.
*/
void Protocol::end_statement()
{
#ifdef WITH_WSREP
/*
Commented out: This sanity check does not hold in general.
Thd->LOCK_thd_data() must be unlocked before sending response
to client, so BF abort may sneak in here.
DBUG_ASSERT(!WSREP(thd) || thd->wsrep_conflict_state() == NO_CONFLICT);
*/
/*
sanity check, don't send end statement while replaying
*/
DBUG_ASSERT(thd->wsrep_trx().state() != wsrep::transaction::s_replaying);
if (WSREP(thd) && thd->wsrep_trx().state() ==
wsrep::transaction::s_replaying)
{
WSREP_ERROR("attempting net_end_statement while replaying");
return;
}
#endif /* WITH_WSREP */
DBUG_ENTER("Protocol::end_statement");
DBUG_ASSERT(! thd->get_stmt_da()->is_sent());
bool error= FALSE;
/* Can not be true, but do not take chances in production. */
if (thd->get_stmt_da()->is_sent())
DBUG_VOID_RETURN;
switch (thd->get_stmt_da()->status()) {
case Diagnostics_area::DA_ERROR:
thd->stop_collecting_unit_results();
/* The query failed, send error to log and abort bootstrap. */
error= send_error(thd->get_stmt_da()->sql_errno(),
thd->get_stmt_da()->message(),
thd->get_stmt_da()->get_sqlstate());
break;
case Diagnostics_area::DA_EOF:
case Diagnostics_area::DA_EOF_BULK:
if (thd->need_report_unit_results()) {
// bulk returning result-set, like INSERT ... RETURNING
// result is already send, needs an EOF with MORE_RESULT_EXISTS
// before sending unit result-set
error= send_eof(thd->server_status | SERVER_MORE_RESULTS_EXISTS,
thd->get_stmt_da()->statement_warn_count());
if (thd->report_collected_unit_results() && thd->is_error())
error= send_error(thd->get_stmt_da()->sql_errno(),
thd->get_stmt_da()->message(),
thd->get_stmt_da()->get_sqlstate());
else
error= send_eof(thd->server_status,
thd->get_stmt_da()->statement_warn_count());
}
else
error= send_eof(thd->server_status,
thd->get_stmt_da()->statement_warn_count());
break;
case Diagnostics_area::DA_OK:
case Diagnostics_area::DA_OK_BULK:
if (thd->report_collected_unit_results())
if (thd->is_error())
error= send_error(thd->get_stmt_da()->sql_errno(),
thd->get_stmt_da()->message(),
thd->get_stmt_da()->get_sqlstate());
else
error= send_eof(thd->server_status,
thd->get_stmt_da()->statement_warn_count());
else
error= send_ok(thd->server_status,
thd->get_stmt_da()->statement_warn_count(),
thd->get_stmt_da()->affected_rows(),
thd->get_stmt_da()->last_insert_id(),
thd->get_stmt_da()->message());
break;
case Diagnostics_area::DA_DISABLED:
break;
case Diagnostics_area::DA_EMPTY:
default:
thd->stop_collecting_unit_results();
DBUG_ASSERT(0);
error= send_ok(thd->server_status, 0, 0, 0, NULL);
break;
}
if (likely(!error))
thd->get_stmt_da()->set_is_sent(true);
DBUG_VOID_RETURN;
}
/**
A default implementation of "OK" packet response to the client.
Currently this implementation is re-used by both network-oriented
protocols -- the binary and text one. They do not differ
in their OK packet format, which allows for a significant simplification
on client side.
*/
bool Protocol::send_ok(uint server_status, uint statement_warn_count,
ulonglong affected_rows, ulonglong last_insert_id,
const char *message)
{
DBUG_ENTER("Protocol::send_ok");
const bool retval=
net_send_ok(thd, server_status, statement_warn_count,
affected_rows, last_insert_id, message, false);
DBUG_RETURN(retval);
}
/**
A default implementation of "EOF" packet response to the client.
Binary and text protocol do not differ in their EOF packet format.
*/
bool Protocol::send_eof(uint server_status, uint statement_warn_count)
{
DBUG_ENTER("Protocol::send_eof");
bool retval= net_send_eof(thd, server_status, statement_warn_count);
DBUG_RETURN(retval);
}
/**
A default implementation of "ERROR" packet response to the client.
Binary and text protocol do not differ in ERROR packet format.
*/
bool Protocol::send_error(uint sql_errno, const char *err_msg,
const char *sql_state)
{
DBUG_ENTER("Protocol::send_error");
const bool retval= net_send_error_packet(thd, sql_errno, err_msg, sql_state);
DBUG_RETURN(retval);
}
/**
Send a progress report to the client
What we send is:
header (255,255,255,1)
stage, max_stage as on byte integers
percentage withing the stage as percentage*1000
(that is, ratio*100000) as a 3 byte integer
proc_info as a string
*/
const uchar progress_header[2]= {(uchar) 255, (uchar) 255 };
void net_send_progress_packet(THD *thd)
{
uchar buff[200], *pos;
const char *proc_info= thd->proc_info ? thd->proc_info : "";
size_t length= strlen(proc_info);
ulonglong progress;
DBUG_ENTER("net_send_progress_packet");
if (unlikely(!thd->net.vio))
DBUG_VOID_RETURN; // Socket is closed
pos= buff;
/*
Store number of strings first. This allows us to later expand the
progress indicator if needed.
*/
*pos++= (uchar) 1; // Number of strings
*pos++= (uchar) thd->progress.stage + 1;
/*
We have the MY_MAX() here to avoid problems if max_stage is not set,
which may happen during automatic repair of table
*/
*pos++= (uchar) MY_MAX(thd->progress.max_stage, thd->progress.stage + 1);
progress= 0;
if (thd->progress.max_counter)
progress= 100000ULL * thd->progress.counter / thd->progress.max_counter;
int3store(pos, progress); // Between 0 & 100000
pos+= 3;
pos= net_store_data(pos, (const uchar*) proc_info,
MY_MIN(length, sizeof(buff)-7));
net_write_command(&thd->net, (uchar) 255, progress_header,
sizeof(progress_header), (uchar*) buff,
(uint) (pos - buff));
DBUG_VOID_RETURN;
}
/****************************************************************************
Functions used by the protocol functions (like net_send_ok) to store
strings and numbers in the header result packet.
****************************************************************************/
/* The following will only be used for short strings < 65K */
uchar *net_store_data(uchar *to, const uchar *from, size_t length)
{
to=net_store_length_fast(to,length);
if (length)
memcpy(to,from,length);
return to+length;
}
uchar *net_store_data(uchar *to,int32 from)
{
char buff[22];
uint length=(uint) (int10_to_str(from,buff,10)-buff);
to=net_store_length_fast(to,length);
memcpy(to,buff,length);
return to+length;
}
uchar *net_store_data(uchar *to,longlong from)
{
char buff[22];
uint length=(uint) (longlong10_to_str(from,buff,10)-buff);
to=net_store_length_fast(to,length);
memcpy(to,buff,length);
return to+length;
}
/*****************************************************************************
Default Protocol functions
*****************************************************************************/
void Protocol::init(THD *thd_arg)
{
thd=thd_arg;
packet= &thd->packet;
convert= &thd->convert_buffer;
#ifndef DBUG_OFF
field_handlers= 0;
field_pos= 0;
#endif
}
/**
Finish the result set with EOF packet, as is expected by the client,
if there is an error evaluating the next row and a continue handler
for the error.
*/
void Protocol::end_partial_result_set(THD *thd_arg)
{
net_send_eof(thd_arg, thd_arg->server_status,
0 /* no warnings, we're inside SP */);
}
bool Protocol::flush()
{
#ifndef EMBEDDED_LIBRARY
bool error;
thd->get_stmt_da()->set_overwrite_status(true);
error= net_flush(&thd->net);
thd->get_stmt_da()->set_overwrite_status(false);
return error;
#else
return 0;
#endif
}
#ifndef EMBEDDED_LIBRARY
class Send_field_packed_extended_metadata: public Binary_string
{
public:
bool append_chunk(mariadb_field_attr_t type, const LEX_CSTRING &value)
{
/*
If we eventually support many metadata chunk types and long metadata
values, we'll need to encode type and length using net_store_length()
and do corresponding changes to the unpacking code in libmariadb.
For now let's just assert that type and length fit into one byte.
*/
DBUG_ASSERT(net_length_size(type) == 1);
DBUG_ASSERT(net_length_size(value.length) == 1);
size_t nbytes= 1/*type*/ + 1/*length*/ + value.length;
if (reserve(nbytes))
return true;
qs_append((char) (uchar) type);
qs_append((char) (uchar) value.length);
qs_append(&value);
return false;
}
bool pack(const Send_field_extended_metadata &src)
{
for (uint i= 0 ; i <= MARIADB_FIELD_ATTR_LAST; i++)
{
const LEX_CSTRING attr= src.attr(i);
if (attr.str && append_chunk((mariadb_field_attr_t) i, attr))
return true;
}
return false;
}
};
bool Protocol_text::store_field_metadata(const THD * thd,
const Send_field &field,
CHARSET_INFO *charset_for_protocol,
uint fieldnr)
{
CHARSET_INFO *thd_charset= thd->variables.character_set_results;
char *pos;
DBUG_ASSERT(field.is_sane());
if (thd->client_capabilities & CLIENT_PROTOCOL_41)
{
const LEX_CSTRING def= {STRING_WITH_LEN("def")};
if (store_ident(def) ||
store_ident(field.db_name) ||
store_ident(field.table_name) ||
store_ident(field.org_table_name) ||
store_ident(field.col_name) ||
store_ident(field.org_col_name))
return true;
if (thd->client_capabilities & MARIADB_CLIENT_EXTENDED_METADATA)
{
Send_field_packed_extended_metadata metadata;
metadata.pack(field);
/*
Don't apply character set conversion:
extended metadata is a binary encoded data.
*/
if (store_binary_string(metadata.ptr(), metadata.length()))
return true;
}
if (packet->realloc(packet->length() + 12))
return true;
/* Store fixed length fields */
pos= (char*) packet->end();
*pos++= 12; // Length of packed fields
/* inject a NULL to test the client */
DBUG_EXECUTE_IF("poison_rs_fields", pos[-1]= (char) 0xfb;);
if (charset_for_protocol == &my_charset_bin || thd_charset == NULL)
{
/* No conversion */
uint id= charset_for_protocol->get_id(MY_COLLATION_ID_TYPE_COMPAT_100800);
DBUG_ASSERT(id <= UINT_MAX16);
int2store(pos, (uint16) id);
int4store(pos + 2, field.length);
}
else
{
/* With conversion */
uint id= thd_charset->get_id(MY_COLLATION_ID_TYPE_COMPAT_100800);
DBUG_ASSERT(id <= UINT_MAX16);
int2store(pos, (uint16) id);
uint32 field_length= field.max_octet_length(charset_for_protocol,
thd_charset);
int4store(pos + 2, field_length);
}
pos[6]= field.type_handler()->type_code_for_protocol();
int2store(pos + 7, field.flags);
pos[9]= (char) field.decimals;
pos[10]= 0; // For the future
pos[11]= 0; // For the future
pos+= 12;
}
else
{
if (store_ident(field.table_name) ||
store_ident(field.col_name) ||
packet->realloc(packet->length() + 10))
return true;
pos= (char*) packet->end();
pos[0]= 3;
int3store(pos + 1, field.length);
pos[4]= 1;
pos[5]= field.type_handler()->type_code_for_protocol();
pos[6]= 3;
int2store(pos + 7, field.flags);
pos[9]= (char) field.decimals;
pos+= 10;
}
packet->length((uint) (pos - packet->ptr()));
return false;
}
/*
MARIADB_CLIENT_CACHE_METADATA support.
Bulk of the code below is dedicated to detecting whether column metadata has
changed after prepare, or between executions of a prepared statement.
For some prepared statements, metadata can't change without going through
Prepared_Statement::reprepare(), which makes detecting changes easy.
Others, "SELECT ?" & Co, are more fragile, and sensitive to input parameters,
or user variables. Detecting metadata change for this class of PS is harder,
we calculate signature (hash value), and check whether this changes between
executions. This is a more expensive method.
*/
/**
Detect whether column info can be changed without
PS repreparing.
Such colum info is called fragile. The opposite of
fragile is.
@param it - Item representing column info
@return true, if columninfo is "fragile", false if it is stable
@todo does not work due to MDEV-23913. Currently,
everything about prepared statements is fragile.
*/
static bool is_fragile_columnifo(Item *it)
{
#define MDEV_23913_FIXED 0
#if MDEV_23913_FIXED
if (dynamic_cast<Item_param *>(it))
return true;
if (dynamic_cast<Item_func_user_var *>(it))
return true;
if (dynamic_cast <Item_sp_variable*>(it))
return true;
/* Check arguments of functions.*/
auto item_args= dynamic_cast<Item_args *>(it);
if (!item_args)
return false;
auto args= item_args->arguments();
auto arg_count= item_args->argument_count();
for (uint i= 0; i < arg_count; i++)