mariadb/sql/sql_alter.cc
Monty 5a759d31f7 Changing field::field_name and Item::name to LEX_CSTRING
Benefits of this patch:
- Removed a lot of calls to strlen(), especially for field_string
- Strings generated by parser are now const strings, less chance of
  accidently changing a string
- Removed a lot of calls with LEX_STRING as parameter (changed to pointer)
- More uniform code
- Item::name_length was not kept up to date. Now fixed
- Several bugs found and fixed (Access to null pointers,
  access of freed memory, wrong arguments to printf like functions)
- Removed a lot of casts from (const char*) to (char*)

Changes:
- This caused some ABI changes
  - lex_string_set now uses LEX_CSTRING
  - Some fucntions are now taking const char* instead of char*
- Create_field::change and after changed to LEX_CSTRING
- handler::connect_string, comment and engine_name() changed to LEX_CSTRING
- Checked printf() related calls to find bugs. Found and fixed several
  errors in old code.
- A lot of changes from LEX_STRING to LEX_CSTRING, especially related to
  parsing and events.
- Some changes from LEX_STRING and LEX_STRING & to LEX_CSTRING*
- Some changes for char* to const char*
- Added printf argument checking for my_snprintf()
- Introduced null_clex_str, star_clex_string, temp_lex_str to simplify
  code
- Added item_empty_name and item_used_name to be able to distingush between
  items that was given an empty name and items that was not given a name
  This is used in sql_yacc.yy to know when to give an item a name.
- select table_name."*' is not anymore same as table_name.*
- removed not used function Item::rename()
- Added comparision of item->name_length before some calls to
  my_strcasecmp() to speed up comparison
- Moved Item_sp_variable::make_field() from item.h to item.cc
- Some minimal code changes to avoid copying to const char *
- Fixed wrong error message in wsrep_mysql_parse()
- Fixed wrong code in find_field_in_natural_join() where real_item() was
  set when it shouldn't
- ER_ERROR_ON_RENAME was used with extra arguments.
- Removed some (wrong) ER_OUTOFMEMORY, as alloc_root will already
  give the error.

TODO:
- Check possible unsafe casts in plugin/auth_examples/qa_auth_interface.c
- Change code to not modify LEX_CSTRING for database name
  (as part of lower_case_table_names)
2017-04-23 22:35:46 +03:00

371 lines
13 KiB
C++

/* Copyright (c) 2010, Oracle and/or its affiliates. All rights reserved.
Copyright (c) 2016, 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 02110-1301 USA */
#include "sql_parse.h" // check_access
#include "sql_table.h" // mysql_alter_table,
// mysql_exchange_partition
#include "sql_alter.h"
#include "wsrep_mysqld.h"
Alter_info::Alter_info(const Alter_info &rhs, MEM_ROOT *mem_root)
:drop_list(rhs.drop_list, mem_root),
alter_list(rhs.alter_list, mem_root),
key_list(rhs.key_list, mem_root),
create_list(rhs.create_list, mem_root),
check_constraint_list(rhs.check_constraint_list, mem_root),
flags(rhs.flags),
keys_onoff(rhs.keys_onoff),
partition_names(rhs.partition_names, mem_root),
num_parts(rhs.num_parts),
requested_algorithm(rhs.requested_algorithm),
requested_lock(rhs.requested_lock)
{
/*
Make deep copies of used objects.
This is not a fully deep copy - clone() implementations
of Alter_drop, Alter_column, Key, foreign_key, Key_part_spec
do not copy string constants. At the same length the only
reason we make a copy currently is that ALTER/CREATE TABLE
code changes input Alter_info definitions, but string
constants never change.
*/
list_copy_and_replace_each_value(drop_list, mem_root);
list_copy_and_replace_each_value(alter_list, mem_root);
list_copy_and_replace_each_value(key_list, mem_root);
list_copy_and_replace_each_value(create_list, mem_root);
/* partition_names are not deeply copied currently */
}
bool Alter_info::set_requested_algorithm(const LEX_CSTRING *str)
{
// To avoid adding new keywords to the grammar, we match strings here.
if (!my_strcasecmp(system_charset_info, str->str, "INPLACE"))
requested_algorithm= ALTER_TABLE_ALGORITHM_INPLACE;
else if (!my_strcasecmp(system_charset_info, str->str, "COPY"))
requested_algorithm= ALTER_TABLE_ALGORITHM_COPY;
else if (!my_strcasecmp(system_charset_info, str->str, "DEFAULT"))
requested_algorithm= ALTER_TABLE_ALGORITHM_DEFAULT;
else
return true;
return false;
}
bool Alter_info::set_requested_lock(const LEX_CSTRING *str)
{
// To avoid adding new keywords to the grammar, we match strings here.
if (!my_strcasecmp(system_charset_info, str->str, "NONE"))
requested_lock= ALTER_TABLE_LOCK_NONE;
else if (!my_strcasecmp(system_charset_info, str->str, "SHARED"))
requested_lock= ALTER_TABLE_LOCK_SHARED;
else if (!my_strcasecmp(system_charset_info, str->str, "EXCLUSIVE"))
requested_lock= ALTER_TABLE_LOCK_EXCLUSIVE;
else if (!my_strcasecmp(system_charset_info, str->str, "DEFAULT"))
requested_lock= ALTER_TABLE_LOCK_DEFAULT;
else
return true;
return false;
}
Alter_table_ctx::Alter_table_ctx()
: datetime_field(NULL), error_if_not_empty(false),
tables_opened(0),
db(NULL), table_name(NULL), alias(NULL),
new_db(NULL), new_name(NULL), new_alias(NULL),
fk_error_if_delete_row(false), fk_error_id(NULL),
fk_error_table(NULL)
#ifndef DBUG_OFF
, tmp_table(false)
#endif
{
}
/*
TODO: new_name_arg changes if lower case table names.
Should be copied or converted before call
*/
Alter_table_ctx::Alter_table_ctx(THD *thd, TABLE_LIST *table_list,
uint tables_opened_arg,
const char *new_db_arg,
const char *new_name_arg)
: datetime_field(NULL), error_if_not_empty(false),
tables_opened(tables_opened_arg),
new_db(new_db_arg), new_name(new_name_arg),
fk_error_if_delete_row(false), fk_error_id(NULL),
fk_error_table(NULL)
#ifndef DBUG_OFF
, tmp_table(false)
#endif
{
/*
Assign members db, table_name, new_db and new_name
to simplify further comparisions: we want to see if it's a RENAME
later just by comparing the pointers, avoiding the need for strcmp.
*/
db= table_list->db;
table_name= table_list->table_name;
alias= (lower_case_table_names == 2) ? table_list->alias : table_name;
if (!new_db || !my_strcasecmp(table_alias_charset, new_db, db))
new_db= db;
if (new_name)
{
DBUG_PRINT("info", ("new_db.new_name: '%s'.'%s'", new_db, new_name));
if (lower_case_table_names == 1) // Convert new_name/new_alias to lower case
{
my_casedn_str(files_charset_info, (char*) new_name);
new_alias= new_name;
}
else if (lower_case_table_names == 2) // Convert new_name to lower case
{
new_alias= new_alias_buff;
strmov(new_alias_buff, new_name);
my_casedn_str(files_charset_info, (char*) new_name);
}
else
new_alias= new_name; // LCTN=0 => case sensitive + case preserving
if (!is_database_changed() &&
!my_strcasecmp(table_alias_charset, new_name, table_name))
{
/*
Source and destination table names are equal:
make is_table_renamed() more efficient.
*/
new_alias= table_name;
new_name= table_name;
}
}
else
{
new_alias= alias;
new_name= table_name;
}
my_snprintf(tmp_name, sizeof(tmp_name), "%s-%lx_%llx", tmp_file_prefix,
current_pid, thd->thread_id);
/* Safety fix for InnoDB */
if (lower_case_table_names)
my_casedn_str(files_charset_info, tmp_name);
if (table_list->table->s->tmp_table == NO_TMP_TABLE)
{
build_table_filename(path, sizeof(path) - 1, db, table_name, "", 0);
build_table_filename(new_path, sizeof(new_path) - 1, new_db, new_name, "", 0);
build_table_filename(new_filename, sizeof(new_filename) - 1,
new_db, new_name, reg_ext, 0);
build_table_filename(tmp_path, sizeof(tmp_path) - 1, new_db, tmp_name, "",
FN_IS_TMP);
}
else
{
/*
We are not filling path, new_path and new_filename members if
we are altering temporary table as these members are not used in
this case. This fact is enforced with assert.
*/
build_tmptable_filename(thd, tmp_path, sizeof(tmp_path));
#ifndef DBUG_OFF
tmp_table= true;
#endif
}
}
bool Sql_cmd_alter_table::execute(THD *thd)
{
LEX *lex= thd->lex;
/* first SELECT_LEX (have special meaning for many of non-SELECTcommands) */
SELECT_LEX *select_lex= &lex->select_lex;
/* first table of first SELECT_LEX */
TABLE_LIST *first_table= (TABLE_LIST*) select_lex->table_list.first;
/*
Code in mysql_alter_table() may modify its HA_CREATE_INFO argument,
so we have to use a copy of this structure to make execution
prepared statement- safe. A shallow copy is enough as no memory
referenced from this structure will be modified.
@todo move these into constructor...
*/
HA_CREATE_INFO create_info(lex->create_info);
Alter_info alter_info(lex->alter_info, thd->mem_root);
ulong priv=0;
ulong priv_needed= ALTER_ACL;
bool result;
DBUG_ENTER("Sql_cmd_alter_table::execute");
if (thd->is_fatal_error) /* out of memory creating a copy of alter_info */
DBUG_RETURN(TRUE);
/*
We also require DROP priv for ALTER TABLE ... DROP PARTITION, as well
as for RENAME TO, as being done by SQLCOM_RENAME_TABLE
*/
if (alter_info.flags & (Alter_info::ALTER_DROP_PARTITION |
Alter_info::ALTER_RENAME))
priv_needed|= DROP_ACL;
/* Must be set in the parser */
DBUG_ASSERT(select_lex->db);
DBUG_ASSERT(!(alter_info.flags & Alter_info::ALTER_EXCHANGE_PARTITION));
DBUG_ASSERT(!(alter_info.flags & Alter_info::ALTER_ADMIN_PARTITION));
if (check_access(thd, priv_needed, first_table->db,
&first_table->grant.privilege,
&first_table->grant.m_internal,
0, 0) ||
check_access(thd, INSERT_ACL | CREATE_ACL, select_lex->db,
&priv,
NULL, /* Don't use first_tab->grant with sel_lex->db */
0, 0))
DBUG_RETURN(TRUE); /* purecov: inspected */
/* If it is a merge table, check privileges for merge children. */
if (create_info.merge_list.first)
{
/*
The user must have (SELECT_ACL | UPDATE_ACL | DELETE_ACL) on the
underlying base tables, even if there are temporary tables with the same
names.
From user's point of view, it might look as if the user must have these
privileges on temporary tables to create a merge table over them. This is
one of two cases when a set of privileges is required for operations on
temporary tables (see also CREATE TABLE).
The reason for this behavior stems from the following facts:
- For merge tables, the underlying table privileges are checked only
at CREATE TABLE / ALTER TABLE time.
In other words, once a merge table is created, the privileges of
the underlying tables can be revoked, but the user will still have
access to the merge table (provided that the user has privileges on
the merge table itself).
- Temporary tables shadow base tables.
I.e. there might be temporary and base tables with the same name, and
the temporary table takes the precedence in all operations.
- For temporary MERGE tables we do not track if their child tables are
base or temporary. As result we can't guarantee that privilege check
which was done in presence of temporary child will stay relevant later
as this temporary table might be removed.
If SELECT_ACL | UPDATE_ACL | DELETE_ACL privileges were not checked for
the underlying *base* tables, it would create a security breach as in
Bug#12771903.
*/
if (check_table_access(thd, SELECT_ACL | UPDATE_ACL | DELETE_ACL,
create_info.merge_list.first, FALSE, UINT_MAX, FALSE))
DBUG_RETURN(TRUE);
}
if (check_grant(thd, priv_needed, first_table, FALSE, UINT_MAX, FALSE))
DBUG_RETURN(TRUE); /* purecov: inspected */
if (lex->name.str && !test_all_bits(priv, INSERT_ACL | CREATE_ACL))
{
// Rename of table
TABLE_LIST tmp_table;
memset(&tmp_table, 0, sizeof(tmp_table));
tmp_table.table_name= lex->name.str;
tmp_table.db= select_lex->db;
tmp_table.grant.privilege= priv;
if (check_grant(thd, INSERT_ACL | CREATE_ACL, &tmp_table, FALSE,
UINT_MAX, FALSE))
DBUG_RETURN(TRUE); /* purecov: inspected */
}
/* Don't yet allow changing of symlinks with ALTER TABLE */
if (create_info.data_file_name)
push_warning_printf(thd, Sql_condition::WARN_LEVEL_WARN,
WARN_OPTION_IGNORED, ER_THD(thd, WARN_OPTION_IGNORED),
"DATA DIRECTORY");
if (create_info.index_file_name)
push_warning_printf(thd, Sql_condition::WARN_LEVEL_WARN,
WARN_OPTION_IGNORED, ER_THD(thd, WARN_OPTION_IGNORED),
"INDEX DIRECTORY");
create_info.data_file_name= create_info.index_file_name= NULL;
thd->enable_slow_log= opt_log_slow_admin_statements;
#ifdef WITH_WSREP
if ((!thd->is_current_stmt_binlog_format_row() ||
!thd->find_temporary_table(first_table)))
{
WSREP_TO_ISOLATION_BEGIN(((lex->name.str) ? select_lex->db : NULL),
((lex->name.str) ? lex->name.str : NULL),
first_table);
}
#endif /* WITH_WSREP */
result= mysql_alter_table(thd, select_lex->db, lex->name.str,
&create_info,
first_table,
&alter_info,
select_lex->order_list.elements,
select_lex->order_list.first,
lex->ignore);
DBUG_RETURN(result);
#ifdef WITH_WSREP
error:
WSREP_WARN("ALTER TABLE isolation failure");
DBUG_RETURN(TRUE);
#endif /* WITH_WSREP */
}
bool Sql_cmd_discard_import_tablespace::execute(THD *thd)
{
/* first SELECT_LEX (have special meaning for many of non-SELECTcommands) */
SELECT_LEX *select_lex= &thd->lex->select_lex;
/* first table of first SELECT_LEX */
TABLE_LIST *table_list= (TABLE_LIST*) select_lex->table_list.first;
if (check_access(thd, ALTER_ACL, table_list->db,
&table_list->grant.privilege,
&table_list->grant.m_internal,
0, 0))
return true;
if (check_grant(thd, ALTER_ACL, table_list, false, UINT_MAX, false))
return true;
thd->enable_slow_log= opt_log_slow_admin_statements;
/*
Check if we attempt to alter mysql.slow_log or
mysql.general_log table and return an error if
it is the case.
TODO: this design is obsolete and will be removed.
*/
if (check_if_log_table(table_list, TRUE, "ALTER"))
return true;
return
mysql_discard_or_import_tablespace(thd, table_list,
m_tablespace_op == DISCARD_TABLESPACE);
}