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Bug#27430 "Crash in subquery code when in PS and table DDL changed after

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PREPARE", review fixes:
- make the patch follow the specification of WL#4166 and remove  
the new error that was originally introduced.
Now the client never gets an error from reprepare, unless it failed.
I.e. even if the statement at hand returns a completely different
result set, this is not considered a server error.
The C API library, that can not handle this situation, was modified to
return a client error.
Added additional test coverage.
This commit is contained in:
kostja@bodhi.(none) 2008-05-20 20:36:26 +04:00
parent 2c0ce2a832
commit 6ae3bca94e
8 changed files with 229 additions and 64 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
include/errmsg.h
View File

@ -96,6 +96,7 @@ extern const char *client_errors[]; /* Error messages */
#define CR_NOT_IMPLEMENTED 2054
#define CR_SERVER_LOST_EXTENDED 2055
#define CR_STMT_CLOSED 2056
#define CR_ERROR_LAST /*Copy last error nr:*/ 2056
#define CR_NEW_STMT_METADATA 2057
#define CR_ERROR_LAST /*Copy last error nr:*/ 2057
/* Add error numbers before CR_ERROR_LAST and change it accordingly. */

24
include/mysql_com.h
View File

@ -184,19 +184,38 @@ enum enum_server_command
#define SERVER_MORE_RESULTS_EXISTS 8 /* Multi query - next query exists */
#define SERVER_QUERY_NO_GOOD_INDEX_USED 16
#define SERVER_QUERY_NO_INDEX_USED 32
/*
/**
The server was able to fulfill the clients request and opened a
read-only non-scrollable cursor for a query. This flag comes
in reply to COM_STMT_EXECUTE and COM_STMT_FETCH commands.
*/
#define SERVER_STATUS_CURSOR_EXISTS 64
/*
/**
This flag is sent when a read-only cursor is exhausted, in reply to
COM_STMT_FETCH command.
*/
#define SERVER_STATUS_LAST_ROW_SENT 128
#define SERVER_STATUS_DB_DROPPED 256 /* A database was dropped */
#define SERVER_STATUS_NO_BACKSLASH_ESCAPES 512
/**
Sent to the client if after a prepared statement reprepare
we discovered that the new statement returns a different
number of result set columns.
*/
#define SERVER_STATUS_METADATA_CHANGED 1024
/**
Server status flags that must be cleared when starting
execution of a new SQL statement.
Flags from this set are only added to the
current server status by the execution engine, but
never removed -- the execution engine expects them
to disappear automagically by the next command.
*/
#define SERVER_STATUS_CLEAR_SET (SERVER_QUERY_NO_GOOD_INDEX_USED| \
SERVER_QUERY_NO_INDEX_USED|\
SERVER_MORE_RESULTS_EXISTS|\
SERVER_STATUS_METADATA_CHANGED)
#define MYSQL_ERRMSG_SIZE 512
#define NET_READ_TIMEOUT 30 /* Timeout on read */
@ -205,6 +224,7 @@ enum enum_server_command
#define ONLY_KILL_QUERY 1
struct st_vio; /* Only C */
typedef struct st_vio Vio;

3
libmysql/errmsg.c
View File

@ -84,6 +84,7 @@ const char *client_errors[]=
"This feature is not implemented yet",
"Lost connection to MySQL server at '%s', system error: %d",
"Statement closed indirectly because of a preceeding %s() call",
"The number of columns in the result set differs from the number of bound buffers. You must reset the statement, rebind the result set columns, and execute the statement again",
""
};
@ -149,6 +150,7 @@ const char *client_errors[]=
"This feature is not implemented yet",
"Lost connection to MySQL server at '%s', system error: %d",
"Statement closed indirectly because of a preceeding %s() call",
"The number of columns in the result set differs from the number of bound buffers. You must reset the statement, rebind the result set columns, and execute the statement again",
""
};
@ -212,6 +214,7 @@ const char *client_errors[]=
"This feature is not implemented yet",
"Lost connection to MySQL server at '%s', system error: %d",
"Statement closed indirectly because of a preceeding %s() call",
"The number of columns in the result set differs from the number of bound buffers. You must reset the statement, rebind the result set columns, and execute the statement again",
""
};
#endif

131
libmysql/libmysql.c
View File

@ -1706,6 +1706,7 @@ static my_bool setup_one_fetch_function(MYSQL_BIND *, MYSQL_FIELD *field);
#define RESET_SERVER_SIDE 1
#define RESET_LONG_DATA 2
#define RESET_STORE_RESULT 4
#define RESET_CLEAR_ERROR 8
static my_bool reset_stmt_handle(MYSQL_STMT *stmt, uint flags);
@ -2090,7 +2091,7 @@ mysql_stmt_prepare(MYSQL_STMT *stmt, const char *query, ulong length)
To be removed when all commands will fully support prepared mode.
*/
static unsigned int alloc_stmt_fields(MYSQL_STMT *stmt)
static void alloc_stmt_fields(MYSQL_STMT *stmt)
{
MYSQL_FIELD *fields, *field, *end;
MEM_ROOT *alloc= &stmt->mem_root;
@ -2108,7 +2109,10 @@ static unsigned int alloc_stmt_fields(MYSQL_STMT *stmt)
!(stmt->bind= (MYSQL_BIND *) alloc_root(alloc,
sizeof(MYSQL_BIND) *
stmt->field_count)))
return 0;
{
set_stmt_error(stmt, CR_OUT_OF_MEMORY, unknown_sqlstate, NULL);
return;
}
for (fields= mysql->fields, end= fields+stmt->field_count,
field= stmt->fields;
@ -2127,13 +2131,15 @@ static unsigned int alloc_stmt_fields(MYSQL_STMT *stmt)
field->def = fields->def ? strdup_root(alloc,fields->def): 0;
field->max_length= 0;
}
return stmt->field_count;
}
/*
/**
Update result set columns metadata if it was sent again in
reply to COM_STMT_EXECUTE.
@note If the new field count is different from the original one,
an error is set and no update is performed.
*/
static void update_stmt_fields(MYSQL_STMT *stmt)
@ -2143,7 +2149,22 @@ static void update_stmt_fields(MYSQL_STMT *stmt)
MYSQL_FIELD *stmt_field= stmt->fields;
MYSQL_BIND *my_bind= stmt->bind_result_done ? stmt->bind : 0;
DBUG_ASSERT(stmt->field_count == stmt->mysql->field_count);
if (stmt->field_count != stmt->mysql->field_count)
{
/*
The tables used in the statement were altered,
and the query now returns a different number of columns.
There is no way to continue without reallocating the bind
array:
- if the number of columns increased, mysql_stmt_fetch()
will write beyond allocated memory
- if the number of columns decreased, some user-bound
buffers will be left unassigned without user knowing
that.
*/
set_stmt_error(stmt, CR_NEW_STMT_METADATA, unknown_sqlstate, NULL);
return;
}
for (; field < field_end; ++field, ++stmt_field)
{
@ -2792,6 +2813,50 @@ my_bool STDCALL mysql_stmt_attr_get(MYSQL_STMT *stmt,
}
/**
Update statement result set metadata from with the new field
information sent during statement execute.
@pre mysql->field_count is not zero
@retval TRUE if error: out of memory or the new
result set has a different number of columns
@retval FALSE success
*/
static void reinit_result_set_metadata(MYSQL_STMT *stmt)
{
/* Server has sent result set metadata */
if (stmt->field_count == 0)
{
/*
This is 'SHOW'/'EXPLAIN'-like query. Current implementation of
prepared statements can't send result set metadata for these queries
on prepare stage. Read it now.
*/
alloc_stmt_fields(stmt);
}
else
{
/*
Update result set metadata if it for some reason changed between
prepare and execute, i.e.:
- in case of 'SELECT ?' we don't know column type unless data was
supplied to mysql_stmt_execute, so updated column type is sent
now.
- if data dictionary changed between prepare and execute, for
example a table used in the query was altered.
Note, that now (4.1.3) we always send metadata in reply to
COM_STMT_EXECUTE (even if it is not necessary), so either this or
previous branch always works.
TODO: send metadata only when it's really necessary and add a warning
'Metadata changed' when it's sent twice.
*/
update_stmt_fields(stmt);
}
}
/*
Send placeholders data to server (if there are placeholders)
and execute prepared statement.
@ -2847,7 +2912,7 @@ int STDCALL mysql_stmt_execute(MYSQL_STMT *stmt)
DBUG_RETURN(1);
}
if (reset_stmt_handle(stmt, RESET_STORE_RESULT))
if (reset_stmt_handle(stmt, RESET_STORE_RESULT | RESET_CLEAR_ERROR))
DBUG_RETURN(1);
/*
No need to check for stmt->state: if the statement wasn't
@ -2855,40 +2920,10 @@ int STDCALL mysql_stmt_execute(MYSQL_STMT *stmt)
*/
if (mysql->methods->stmt_execute(stmt))
DBUG_RETURN(1);
stmt->state= MYSQL_STMT_EXECUTE_DONE;
if (mysql->field_count)
{
/* Server has sent result set metadata */
if (stmt->field_count == 0)
{
/*
This is 'SHOW'/'EXPLAIN'-like query. Current implementation of
prepared statements can't send result set metadata for these queries
on prepare stage. Read it now.
*/
alloc_stmt_fields(stmt);
}
else
{
/*
Update result set metadata if it for some reason changed between
prepare and execute, i.e.:
- in case of 'SELECT ?' we don't know column type unless data was
supplied to mysql_stmt_execute, so updated column type is sent
now.
- if data dictionary changed between prepare and execute, for
example a table used in the query was altered.
Note, that now (4.1.3) we always send metadata in reply to
COM_STMT_EXECUTE (even if it is not necessary), so either this or
previous branch always works.
TODO: send metadata only when it's really necessary and add a warning
'Metadata changed' when it's sent twice.
*/
update_stmt_fields(stmt);
}
}
stmt->state= MYSQL_STMT_EXECUTE_DONE;
if (stmt->field_count)
{
reinit_result_set_metadata(stmt);
if (stmt->server_status & SERVER_STATUS_CURSOR_EXISTS)
{
mysql->status= MYSQL_STATUS_READY;
@ -2903,7 +2938,7 @@ int STDCALL mysql_stmt_execute(MYSQL_STMT *stmt)
network or b) is more efficient if all (few) result set rows are
precached on client and server's resources are freed.
*/
DBUG_RETURN(mysql_stmt_store_result(stmt));
mysql_stmt_store_result(stmt);
}
else
{
@ -2912,7 +2947,7 @@ int STDCALL mysql_stmt_execute(MYSQL_STMT *stmt)
stmt->read_row_func= stmt_read_row_unbuffered;
}
}
DBUG_RETURN(0);
DBUG_RETURN(test(stmt->last_errno));
}
@ -4766,6 +4801,12 @@ int STDCALL mysql_stmt_store_result(MYSQL_STMT *stmt)
DBUG_RETURN(1);
}
if (stmt->last_errno)
{
/* An attempt to use an invalid statement handle. */
DBUG_RETURN(1);
}
if (mysql->status == MYSQL_STATUS_READY &&
stmt->server_status & SERVER_STATUS_CURSOR_EXISTS)
{
@ -4973,9 +5014,10 @@ static my_bool reset_stmt_handle(MYSQL_STMT *stmt, uint flags)
stmt->state= MYSQL_STMT_INIT_DONE;
return 1;
}
stmt_clear_error(stmt);
}
}
if (flags & RESET_CLEAR_ERROR)
stmt_clear_error(stmt);
stmt->state= MYSQL_STMT_PREPARE_DONE;
}
return 0;
@ -4986,7 +5028,8 @@ my_bool STDCALL mysql_stmt_free_result(MYSQL_STMT *stmt)
DBUG_ENTER("mysql_stmt_free_result");
/* Free the client side and close the server side cursor if there is one */
DBUG_RETURN(reset_stmt_handle(stmt, RESET_LONG_DATA | RESET_STORE_RESULT));
DBUG_RETURN(reset_stmt_handle(stmt, RESET_LONG_DATA | RESET_STORE_RESULT |
RESET_CLEAR_ERROR));
}
/********************************************************************
@ -5067,7 +5110,9 @@ my_bool STDCALL mysql_stmt_reset(MYSQL_STMT *stmt)
DBUG_RETURN(1);
}
/* Reset the client and server sides of the prepared statement */
DBUG_RETURN(reset_stmt_handle(stmt, RESET_SERVER_SIDE | RESET_LONG_DATA));
DBUG_RETURN(reset_stmt_handle(stmt,
RESET_SERVER_SIDE | RESET_LONG_DATA |
RESET_CLEAR_ERROR));
}
/*

3
sql/share/errmsg.txt
View File

@ -6130,6 +6130,3 @@ ER_LOG_PURGE_NO_FILE
ER_NEED_REPREPARE
eng "Prepared statement needs to be re-prepared"
ER_PS_REBIND
eng "Prepared statement result set has changed, a rebind needed"

15
sql/sql_parse.cc
View File

@ -914,8 +914,11 @@ bool dispatch_command(enum enum_server_command command, THD *thd,
/* TODO: set thd->lex->sql_command to SQLCOM_END here */
VOID(pthread_mutex_unlock(&LOCK_thread_count));
thd->server_status&=
~(SERVER_QUERY_NO_INDEX_USED | SERVER_QUERY_NO_GOOD_INDEX_USED);
/**
Clear the set of flags that are expected to be cleared at the
beginning of each command.
*/
thd->server_status&= ~SERVER_STATUS_CLEAR_SET;
switch (command) {
case COM_INIT_DB:
{
@ -5377,9 +5380,11 @@ void mysql_reset_thd_for_next_command(THD *thd)
thd->query_start_used= 0;
thd->is_fatal_error= thd->time_zone_used= 0;
thd->server_status&= ~ (SERVER_MORE_RESULTS_EXISTS |
SERVER_QUERY_NO_INDEX_USED |
SERVER_QUERY_NO_GOOD_INDEX_USED);
/*
Clear the status flag that are expected to be cleared at the
beginning of each SQL statement.
*/
thd->server_status&= ~SERVER_STATUS_CLEAR_SET;
/*
If in autocommit mode and not in a transaction, reset
OPTION_STATUS_NO_TRANS_UPDATE | OPTION_KEEP_LOG to not get warnings

7
sql/sql_prepare.cc
View File

@ -3315,7 +3315,7 @@ Prepared_statement::reprepare()
@param[in] copy the re-prepared prepared statement to verify
the metadata of
@retval TRUE error, ER_PS_NEED_REBIND is reported
@retval TRUE error, ER_PS_REBIND is reported
@retval FALSE statement return no or compatible metadata
*/
@ -3333,9 +3333,8 @@ bool Prepared_statement::validate_metadata(Prepared_statement *copy)
if (lex->select_lex.item_list.elements !=
copy->lex->select_lex.item_list.elements)
{
/** Column counts mismatch. */
my_error(ER_PS_REBIND, MYF(0));
return TRUE;
/** Column counts mismatch, update the client */
thd->server_status|= SERVER_STATUS_METADATA_CHANGED;
}
return FALSE;

107
tests/mysql_client_test.c
View File

@ -6668,10 +6668,10 @@ static void test_pure_coverage()
check_execute_r(stmt, rc); /* unsupported buffer type */
rc= mysql_stmt_store_result(stmt);
check_execute(stmt, rc);
DIE_UNLESS(rc);
rc= mysql_stmt_store_result(stmt);
check_execute_r(stmt, rc); /* commands out of sync */
DIE_UNLESS(rc); /* Old error must be reset first */
mysql_stmt_close(stmt);
@ -8423,6 +8423,9 @@ static void test_fetch_offset()
rc= mysql_stmt_fetch_column(stmt, my_bind, 0, 0);
check_execute_r(stmt, rc);
rc= mysql_stmt_execute(stmt);
check_execute(stmt, rc);
rc= mysql_stmt_bind_result(stmt, my_bind);
check_execute(stmt, rc);
@ -9901,7 +9904,7 @@ static void test_rename()
MYSQL_STMT *stmt;
const char *query= "rename table t1 to t2, t3 to t4";
int rc;
myheader("test_table_manipulation");
myheader("test_table_rename");
rc= mysql_query(mysql, "DROP TABLE IF EXISTS t1, t2, t3, t4");
myquery(rc);
@ -17383,7 +17386,7 @@ static void test_bug28386()
DBUG_VOID_RETURN;
}
static void test_wl4166()
static void test_wl4166_1()
{
MYSQL_STMT *stmt;
int int_data;
@ -17399,7 +17402,7 @@ static void test_wl4166()
int rc;
int i;
myheader("test_wl4166");
myheader("test_wl4166_1");
rc= mysql_query(mysql, "DROP TABLE IF EXISTS table_4166");
myquery(rc);
@ -17498,6 +17501,97 @@ static void test_wl4166()
rc= mysql_query(mysql, "DROP TABLE table_4166");
myquery(rc);
}
static void test_wl4166_2()
{
MYSQL_STMT *stmt;
int c_int;
MYSQL_TIME d_date;
MYSQL_BIND bind_out[2];
int rc;
int i;
myheader("test_wl4166_2");
rc= mysql_query(mysql, "drop table if exists t1");
myquery(rc);
rc= mysql_query(mysql, "create table t1 (c_int int, d_date date)");
myquery(rc);
rc= mysql_query(mysql,
"insert into t1 (c_int, d_date) values (42, '1948-05-15')");
myquery(rc);
stmt= mysql_simple_prepare(mysql, "select * from t1");
check_stmt(stmt);
bzero(bind_out, sizeof(bind_out));
bind_out[0].buffer_type= MYSQL_TYPE_LONG;
bind_out[0].buffer= (void*) &c_int;
bind_out[1].buffer_type= MYSQL_TYPE_DATE;
bind_out[1].buffer= (void*) &d_date;
rc= mysql_stmt_bind_result(stmt, bind_out);
check_execute(stmt, rc);
/* int -> varchar transition */
rc= mysql_query(mysql,
"alter table t1 change column c_int c_int varchar(11)");
myquery(rc);
rc= mysql_stmt_execute(stmt);
check_execute(stmt, rc);
rc= mysql_stmt_fetch(stmt);
check_execute(stmt, rc);
DIE_UNLESS(c_int == 42);
DIE_UNLESS(d_date.year == 1948);
DIE_UNLESS(d_date.month == 5);
DIE_UNLESS(d_date.day == 15);
rc= mysql_stmt_fetch(stmt);
DIE_UNLESS(rc == MYSQL_NO_DATA);
/* varchar to int retrieval with truncation */
rc= mysql_query(mysql, "update t1 set c_int='abcde'");
myquery(rc);
rc= mysql_stmt_execute(stmt);
check_execute(stmt, rc);
rc= mysql_stmt_fetch(stmt);
check_execute_r(stmt, rc);
DIE_UNLESS(c_int == 0);
rc= mysql_stmt_fetch(stmt);
DIE_UNLESS(rc == MYSQL_NO_DATA);
/* alter table and increase the number of columns */
rc= mysql_query(mysql, "alter table t1 add column d_int int");
myquery(rc);
rc= mysql_stmt_execute(stmt);
check_execute_r(stmt, rc);
rc= mysql_stmt_reset(stmt);
check_execute(stmt, rc);
/* decrease the number of columns */
rc= mysql_query(mysql, "alter table t1 drop d_date, drop d_int");
myquery(rc);
rc= mysql_stmt_execute(stmt);
check_execute_r(stmt, rc);
mysql_stmt_close(stmt);
rc= mysql_query(mysql, "drop table t1");
myquery(rc);
}
@ -17807,7 +17901,8 @@ static struct my_tests_st my_tests[]= {
{ "test_bug31418", test_bug31418 },
{ "test_bug31669", test_bug31669 },
{ "test_bug28386", test_bug28386 },
{ "test_wl4166", test_wl4166 },
{ "test_wl4166_1", test_wl4166_1 },
{ "test_wl4166_2", test_wl4166_2 },
{ 0, 0 }
};