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Fix for BUG#25082: default database change on trigger

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execution breaks replication.

When a stored routine is executed, we switch current
database to the database, in which the routine
has been created. When the stored routine finishes,
we switch back to the original database.

The problem was that if the original database does not
exist (anymore) after routine execution, we raised an error.

The fix is to report a warning, and switch to the NULL database.


mysql-test/r/sp.result:
  Updated result file.
mysql-test/t/sp.test:
  Added test case for BUG#25082.
sql/mysql_priv.h:
  1. Change mysql_change_db() prototype;
  2. Polishing.
sql/sp.cc:
  Polishing.
sql/sp_head.cc:
  Polishing.
sql/sql_db.cc:
  1. Polishing.
  2. Fix mysql_change_db().
sql/sql_parse.cc:
  Polishing.
sql/sql_show.cc:
  Polishing.
This commit is contained in:
unknown
2007-03-27 21:55:01 +04:00
parent 21af9a55dd
commit 6a594ffd18
8 changed files with 309 additions and 143 deletions
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336
sql/sql_db.cc
View File

@@ -461,7 +461,7 @@ bool mysql_create_db(THD *thd, char *db, HA_CREATE_INFO *create_info,
DBUG_ENTER("mysql_create_db");
/* do not create 'information_schema' db */
if (!my_strcasecmp(system_charset_info, db, information_schema_name.str))
if (!my_strcasecmp(system_charset_info, db, INFORMATION_SCHEMA_NAME.str))
{
my_error(ER_DB_CREATE_EXISTS, MYF(0), db);
DBUG_RETURN(-1);
@@ -1126,154 +1126,256 @@ err:
}
/*
Change the current database.
/**
@brief Internal implementation: switch current database to a valid one.
SYNOPSIS
mysql_change_db()
thd thread handle
name database name
no_access_check if TRUE, don't do access check. In this
case name may be ""
DESCRIPTION
Check that the database name corresponds to a valid and
existent database, check access rights (unless called with
no_access_check), and set the current database. This function
is called to change the current database upon user request
(COM_CHANGE_DB command) or temporarily, to execute a stored
routine.
NOTES
This function is not the only way to switch the database that
is currently employed. When the replication slave thread
switches the database before executing a query, it calls
thd->set_db directly. However, if the query, in turn, uses
a stored routine, the stored routine will use this function,
even if it's run on the slave.
This function allocates the name of the database on the system
heap: this is necessary to be able to uniformly change the
database from any module of the server. Up to 5.0 different
modules were using different memory to store the name of the
database, and this led to memory corruption: a stack pointer
set by Stored Procedures was used by replication after the
stack address was long gone.
This function does not send anything, including error
messages, to the client. If that should be sent to the client,
call net_send_error after this function.
RETURN VALUES
0 OK
1 error
@param thd Thread context.
@param new_db_name Name of the database to switch to. The function will
take ownership of the name (the caller must not free
the allocated memory). If the name is NULL, we're
going to switch to NULL db.
@param new_db_access Privileges of the new database.
@param new_db_charset Character set of the new database.
*/
bool mysql_change_db(THD *thd, const char *name, bool no_access_check)
static void mysql_change_db_impl(THD *thd,
LEX_STRING *new_db_name,
ulong new_db_access,
CHARSET_INFO *new_db_charset)
{
int db_length;
char *db_name;
bool system_db= 0;
#ifndef NO_EMBEDDED_ACCESS_CHECKS
ulong db_access;
Security_context *sctx= thd->security_ctx;
LINT_INIT(db_access);
#endif
DBUG_ENTER("mysql_change_db");
DBUG_PRINT("enter",("name: '%s'",name));
/* 1. Change current database in THD. */
if (name == NULL || name[0] == '\0' && no_access_check == FALSE)
if (new_db_name == NULL)
{
my_message(ER_NO_DB_ERROR, ER(ER_NO_DB_ERROR), MYF(0));
DBUG_RETURN(1); /* purecov: inspected */
/*
THD::set_db() does all the job -- it frees previous database name and
sets the new one.
*/
thd->set_db(NULL, 0);
}
else if (name[0] == '\0')
else if (new_db_name == &INFORMATION_SCHEMA_NAME)
{
/* Called from SP to restore the original database, which was NULL */
DBUG_ASSERT(no_access_check);
system_db= 1;
db_name= NULL;
db_length= 0;
goto end;
/*
Here we must use THD::set_db(), because we want to copy
INFORMATION_SCHEMA_NAME constant.
*/
thd->set_db(INFORMATION_SCHEMA_NAME.str, INFORMATION_SCHEMA_NAME.length);
}
else
{
/*
Here we already have a copy of database name to be used in THD. So,
we just call THD::reset_db(). Since THD::reset_db() does not releases
the previous database name, we should do it explicitly.
*/
x_free(thd->db);
thd->reset_db(new_db_name->str, new_db_name->length);
}
/* 2. Update security context. */
#ifndef NO_EMBEDDED_ACCESS_CHECKS
thd->security_ctx->db_access= new_db_access;
#endif
/* 3. Update db-charset environment variables. */
thd->db_charset= new_db_charset;
thd->variables.collation_database= new_db_charset;
}
/**
@brief Change the current database.
@param thd thread handle
@param name database name
@param force_switch if this flag is set (TRUE), mysql_change_db() will
switch to NULL db if the specified database is not
available anymore. Corresponding warning will be
thrown in this case. This flag is used to change
database in stored-routine-execution code.
@details Check that the database name corresponds to a valid and existent
database, check access rights (unless called with no_access_check), and
set the current database. This function is called to change the current
database upon user request (COM_CHANGE_DB command) or temporarily, to
execute a stored routine.
This function is not the only way to switch the database that is
currently employed. When the replication slave thread switches the
database before executing a query, it calls thd->set_db directly.
However, if the query, in turn, uses a stored routine, the stored routine
will use this function, even if it's run on the slave.
This function allocates the name of the database on the system heap: this
is necessary to be able to uniformly change the database from any module
of the server. Up to 5.0 different modules were using different memory to
store the name of the database, and this led to memory corruption:
a stack pointer set by Stored Procedures was used by replication after
the stack address was long gone.
@return Operation status
@retval FALSE Success
@retval TRUE Error
*/
bool mysql_change_db(THD *thd, const LEX_STRING *new_db_name, bool force_switch)
{
LEX_STRING new_db_file_name;
Security_context *sctx= thd->security_ctx;
ulong db_access= sctx->db_access;
DBUG_ENTER("mysql_change_db");
DBUG_PRINT("enter",("name: '%s'", new_db_name->str));
if (new_db_name == NULL ||
new_db_name->length == 0 ||
new_db_name->str == NULL)
{
if (force_switch)
{
push_warning_printf(thd, MYSQL_ERROR::WARN_LEVEL_NOTE,
ER_NO_DB_ERROR, ER(ER_NO_DB_ERROR));
/* Change db to NULL. */
mysql_change_db_impl(thd, NULL, 0, thd->variables.collation_server);
DBUG_RETURN(FALSE);
}
else
{
my_message(ER_NO_DB_ERROR, ER(ER_NO_DB_ERROR), MYF(0));
DBUG_RETURN(TRUE);
}
}
if (my_strcasecmp(system_charset_info, new_db_name->str,
INFORMATION_SCHEMA_NAME.str) == 0)
{
/* Switch database to INFORMATION_SCHEMA. */
mysql_change_db_impl(thd, &INFORMATION_SCHEMA_NAME, SELECT_ACL,
system_charset_info);
DBUG_RETURN(FALSE);
}
/*
Now we need to make a copy because check_db_name requires a
non-constant argument. TODO: fix check_db_name.
non-constant argument. Actually, it takes database file name.
TODO: fix check_db_name().
*/
if ((db_name= my_strdup(name, MYF(MY_WME))) == NULL)
DBUG_RETURN(1); /* the error is set */
db_length= strlen(db_name);
if (check_db_name(db_name))
new_db_file_name.str= my_strdup(new_db_name->str, MYF(MY_WME));
new_db_file_name.length= new_db_name->length;
if (new_db_file_name.str == NULL)
DBUG_RETURN(TRUE); /* the error is set */
/*
NOTE: if check_db_name() fails, we should throw an error in any case,
even if we are called from sp_head::execute().
It's next to impossible however to get this error when we are called
from sp_head::execute(). But let's switch database to NULL in this case
to be sure.
*/
if (check_db_name(new_db_file_name.str))
{
my_error(ER_WRONG_DB_NAME, MYF(0), db_name);
my_free(db_name, MYF(0));
DBUG_RETURN(1);
}
DBUG_PRINT("info",("Use database: %s", db_name));
if (!my_strcasecmp(system_charset_info, db_name, information_schema_name.str))
{
system_db= 1;
#ifndef NO_EMBEDDED_ACCESS_CHECKS
db_access= SELECT_ACL;
#endif
goto end;
my_error(ER_WRONG_DB_NAME, MYF(0), new_db_file_name.str);
my_free(new_db_file_name.str, MYF(0));
if (force_switch)
{
/* Change db to NULL. */
mysql_change_db_impl(thd, NULL, 0, thd->variables.collation_server);
}
DBUG_RETURN(TRUE);
}
DBUG_PRINT("info",("Use database: %s", new_db_file_name.str));
#ifndef NO_EMBEDDED_ACCESS_CHECKS
if (!no_access_check)
if (!force_switch) /* FIXME: this is BUG#27337. */
{
if (test_all_bits(sctx->master_access, DB_ACLS))
db_access=DB_ACLS;
else
db_access= (acl_get(sctx->host, sctx->ip, sctx->priv_user, db_name, 0) |
sctx->master_access);
if (!(db_access & DB_ACLS) && (!grant_option ||
check_grant_db(thd,db_name)))
db_access=
test_all_bits(sctx->master_access, DB_ACLS) ?
DB_ACLS :
acl_get(sctx->host,
sctx->ip,
sctx->priv_user,
new_db_file_name.str,
FALSE) | sctx->master_access;
if (!force_switch &&
!(db_access & DB_ACLS) &&
(!grant_option || check_grant_db(thd, new_db_file_name.str)))
{
my_error(ER_DBACCESS_DENIED_ERROR, MYF(0),
sctx->priv_user,
sctx->priv_host,
db_name);
new_db_file_name.str);
mysql_log.write(thd, COM_INIT_DB, ER(ER_DBACCESS_DENIED_ERROR),
sctx->priv_user, sctx->priv_host, db_name);
my_free(db_name, MYF(0));
DBUG_RETURN(1);
sctx->priv_user, sctx->priv_host, new_db_file_name.str);
my_free(new_db_file_name.str, MYF(0));
DBUG_RETURN(TRUE);
}
}
#endif
if (check_db_dir_existence(db_name))
if (check_db_dir_existence(new_db_file_name.str))
{
my_error(ER_BAD_DB_ERROR, MYF(0), db_name);
my_free(db_name, MYF(0));
DBUG_RETURN(1);
if (force_switch)
{
push_warning_printf(thd, MYSQL_ERROR::WARN_LEVEL_NOTE,
ER_BAD_DB_ERROR, ER(ER_BAD_DB_ERROR),
new_db_file_name.str);
my_free(new_db_file_name.str, MYF(0));
/* Change db to NULL. */
mysql_change_db_impl(thd, NULL, 0, thd->variables.collation_server);
DBUG_RETURN(FALSE);
}
else
{
my_error(ER_BAD_DB_ERROR, MYF(0), new_db_file_name.str);
my_free(new_db_file_name.str, MYF(0));
DBUG_RETURN(TRUE);
}
}
end:
x_free(thd->db);
DBUG_ASSERT(db_name == NULL || db_name[0] != '\0');
thd->reset_db(db_name, db_length); // THD::~THD will free this
#ifndef NO_EMBEDDED_ACCESS_CHECKS
if (!no_access_check)
sctx->db_access= db_access;
#endif
if (system_db)
{
thd->db_charset= system_charset_info;
thd->variables.collation_database= system_charset_info;
}
else
{
HA_CREATE_INFO create;
/*
NOTE: in mysql_change_db_impl() new_db_file_name is assigned to THD
attributes and will be freed in THD::~THD().
*/
load_db_opt_by_name(thd, db_name, &create);
{
HA_CREATE_INFO db_options;
thd->db_charset= create.default_table_charset ?
create.default_table_charset :
thd->variables.collation_server;
thd->variables.collation_database= thd->db_charset;
load_db_opt_by_name(thd, new_db_name->str, &db_options);
mysql_change_db_impl(thd, &new_db_file_name, db_access,
db_options.default_table_charset ?
db_options.default_table_charset :
thd->variables.collation_server);
}
DBUG_RETURN(0);
DBUG_RETURN(FALSE);
}