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Harden tableam against nonexistant / wrong kind of AMs. 

Previously it was allowed to set default_table_access_method to an
empty string. That makes sense for default_tablespace, where that was
copied from, as it signals falling back to the database's default
tablespace. As there is no equivalent for table AMs, forbid that.

Also make sure to throw a usable error when creating a table using an
index AM, by using get_am_type_oid() to implement get_table_am_oid()
instead of a separate copy. Previously we'd error out only later, in
GetTableAmRoutine().

Thirdly remove GetTableAmRoutineByAmId() - it was only used in an
earlier version of 8586bf7ed8.

Add tests for the above (some for index AMs as well).
This commit is contained in:
Andres Freund 2019-04-04 17:17:50 -07:00
parent 344b7e11bb
commit ea97e440b8
9 changed files with 119 additions and 110 deletions
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110
src/backend/access/table/tableamapi.c
View File

@ -17,14 +17,12 @@
#include "access/xact.h"
#include "catalog/pg_am.h"
#include "catalog/pg_proc.h"
#include "commands/defrem.h"
#include "utils/fmgroids.h"
#include "utils/memutils.h"
#include "utils/syscache.h"
static Oid get_table_am_oid(const char *tableamname, bool missing_ok);
/*
* GetTableAmRoutine
* Call the specified access method handler routine to get its
@ -41,7 +39,7 @@ GetTableAmRoutine(Oid amhandler)
routine = (TableAmRoutine *) DatumGetPointer(datum);
if (routine == NULL || !IsA(routine, TableAmRoutine))
elog(ERROR, "Table access method handler %u did not return a TableAmRoutine struct",
elog(ERROR, "table access method handler %u did not return a TableAmRoutine struct",
amhandler);
/*
@ -98,106 +96,30 @@ GetTableAmRoutine(Oid amhandler)
return routine;
}
/*
* GetTableAmRoutineByAmId - look up the handler of the table access
* method with the given OID, and get its TableAmRoutine struct.
*/
const TableAmRoutine *
GetTableAmRoutineByAmId(Oid amoid)
{
regproc amhandler;
HeapTuple tuple;
Form_pg_am amform;
/* Get handler function OID for the access method */
tuple = SearchSysCache1(AMOID, ObjectIdGetDatum(amoid));
if (!HeapTupleIsValid(tuple))
elog(ERROR, "cache lookup failed for access method %u",
amoid);
amform = (Form_pg_am) GETSTRUCT(tuple);
/* Check that it is a table access method */
if (amform->amtype != AMTYPE_TABLE)
ereport(ERROR,
(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
errmsg("access method \"%s\" is not of type %s",
NameStr(amform->amname), "TABLE")));
amhandler = amform->amhandler;
/* Complain if handler OID is invalid */
if (!RegProcedureIsValid(amhandler))
ereport(ERROR,
(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
errmsg("table access method \"%s\" does not have a handler",
NameStr(amform->amname))));
ReleaseSysCache(tuple);
/* And finally, call the handler function to get the API struct. */
return GetTableAmRoutine(amhandler);
}
/*
* get_table_am_oid - given a table access method name, look up the OID
*
* If missing_ok is false, throw an error if table access method name not
* found. If true, just return InvalidOid.
*/
static Oid
get_table_am_oid(const char *tableamname, bool missing_ok)
{
Oid result;
Relation rel;
TableScanDesc scandesc;
HeapTuple tuple;
ScanKeyData entry[1];
/*
* Search pg_am. We use a heapscan here even though there is an index on
* name, on the theory that pg_am will usually have just a few entries and
* so an indexed lookup is a waste of effort.
*/
rel = heap_open(AccessMethodRelationId, AccessShareLock);
ScanKeyInit(&entry[0],
Anum_pg_am_amname,
BTEqualStrategyNumber, F_NAMEEQ,
CStringGetDatum(tableamname));
scandesc = table_beginscan_catalog(rel, 1, entry);
tuple = heap_getnext(scandesc, ForwardScanDirection);
/* We assume that there can be at most one matching tuple */
if (HeapTupleIsValid(tuple) &&
((Form_pg_am) GETSTRUCT(tuple))->amtype == AMTYPE_TABLE)
result = ((Form_pg_am) GETSTRUCT(tuple))->oid;
else
result = InvalidOid;
table_endscan(scandesc);
heap_close(rel, AccessShareLock);
if (!OidIsValid(result) && !missing_ok)
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_OBJECT),
errmsg("table access method \"%s\" does not exist",
tableamname)));
return result;
}
/* check_hook: validate new default_table_access_method */
bool
check_default_table_access_method(char **newval, void **extra, GucSource source)
{
if (**newval == '\0')
{
GUC_check_errdetail("default_table_access_method may not be empty.");
return false;
}
if (strlen(*newval) >= NAMEDATALEN)
{
GUC_check_errdetail("default_table_access_method is too long (maximum %d characters).",
NAMEDATALEN - 1);
return false;
}
/*
* If we aren't inside a transaction, we cannot do database access so
* cannot verify the name. Must accept the value on faith.
*/
if (IsTransactionState())
{
if (**newval != '\0' &&
!OidIsValid(get_table_am_oid(*newval, true)))
if (!OidIsValid(get_table_am_oid(*newval, true)))
{
/*
* When source == PGC_S_TEST, don't throw a hard error for a

10
src/backend/commands/amcmds.c
View File

@ -189,6 +189,16 @@ get_index_am_oid(const char *amname, bool missing_ok)
return get_am_type_oid(amname, AMTYPE_INDEX, missing_ok);
}
/*
* get_table_am_oid - given an access method name, look up its OID
* and verify it corresponds to an table AM.
*/
Oid
get_table_am_oid(const char *amname, bool missing_ok)
{
return get_am_type_oid(amname, AMTYPE_TABLE, missing_ok);
}
/*
* get_am_oid - given an access method name, look up its OID.
* The type is not checked.

17
src/backend/commands/tablecmds.c
View File

@ -832,22 +832,9 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId,
relkind == RELKIND_MATVIEW)
accessMethod = default_table_access_method;
/*
* look up the access method, verify it can handle the requested features
*/
/* look up the access method, verify it is for a table */
if (accessMethod != NULL)
{
HeapTuple tuple;
tuple = SearchSysCache1(AMNAME, PointerGetDatum(accessMethod));
if (!HeapTupleIsValid(tuple))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_OBJECT),
errmsg("table access method \"%s\" does not exist",
accessMethod)));
accessMethodId = ((Form_pg_am) GETSTRUCT(tuple))->oid;
ReleaseSysCache(tuple);
}
accessMethodId = get_table_am_oid(accessMethod, false);
/*
* Create the relation. Inherited defaults and constraints are passed in

1
src/include/access/tableam.h
View File

@ -1616,7 +1616,6 @@ extern void table_block_parallelscan_startblock_init(Relation rel,
*/
extern const TableAmRoutine *GetTableAmRoutine(Oid amhandler);
extern const TableAmRoutine *GetTableAmRoutineByAmId(Oid amoid);
extern const TableAmRoutine *GetHeapamTableAmRoutine(void);
extern bool check_default_table_access_method(char **newval, void **extra,
GucSource source);

1
src/include/commands/defrem.h
View File

@ -156,6 +156,7 @@ extern Datum transformGenericOptions(Oid catalogId,
extern ObjectAddress CreateAccessMethod(CreateAmStmt *stmt);
extern void RemoveAccessMethodById(Oid amOid);
extern Oid get_index_am_oid(const char *amname, bool missing_ok);
extern Oid get_table_am_oid(const char *amname, bool missing_ok);
extern Oid get_am_oid(const char *amname, bool missing_ok);
extern char *get_am_name(Oid amOid);

33
src/test/regress/expected/create_am.out
View File

@ -3,6 +3,11 @@
--
-- Make gist2 over gisthandler. In fact, it would be a synonym to gist.
CREATE ACCESS METHOD gist2 TYPE INDEX HANDLER gisthandler;
-- Verify return type checks for handlers
CREATE ACCESS METHOD bogus TYPE INDEX HANDLER int4in;
ERROR: function int4in(internal) does not exist
CREATE ACCESS METHOD bogus TYPE INDEX HANDLER heap_tableam_handler;
ERROR: function heap_tableam_handler must return type index_am_handler
-- Try to create gist2 index on fast_emp4000: fail because opclass doesn't exist
CREATE INDEX grect2ind2 ON fast_emp4000 USING gist2 (home_base);
ERROR: data type box has no default operator class for access method "gist2"
@ -102,8 +107,24 @@ NOTICE: drop cascades to index grect2ind2
--
-- Test table access methods
--
-- prevent empty values
SET default_table_access_method = '';
ERROR: invalid value for parameter "default_table_access_method": ""
DETAIL: default_table_access_method may not be empty.
-- prevent nonexistant values
SET default_table_access_method = 'I do not exist AM';
ERROR: invalid value for parameter "default_table_access_method": "I do not exist AM"
DETAIL: Table access method "I do not exist AM" does not exist.
-- prevent setting it to an index AM
SET default_table_access_method = 'btree';
ERROR: access method "btree" is not of type TABLE
-- Create a heap2 table am handler with heapam handler
CREATE ACCESS METHOD heap2 TYPE TABLE HANDLER heap_tableam_handler;
-- Verify return type checks for handlers
CREATE ACCESS METHOD bogus TYPE TABLE HANDLER int4in;
ERROR: function int4in(internal) does not exist
CREATE ACCESS METHOD bogus TYPE TABLE HANDLER bthandler;
ERROR: function bthandler must return type table_am_handler
SELECT amname, amhandler, amtype FROM pg_am where amtype = 't' ORDER BY 1, 2;
amname | amhandler | amtype
--------+----------------------+--------
@ -253,6 +274,18 @@ ORDER BY 3, 1, 2;
-- don't want to keep those tables, nor the default
ROLLBACK;
-- Third, check that we can neither create a table using a nonexistant
-- AM, nor using an index AM
CREATE TABLE i_am_a_failure() USING "";
ERROR: zero-length delimited identifier at or near """"
LINE 1: CREATE TABLE i_am_a_failure() USING "";
^
CREATE TABLE i_am_a_failure() USING i_do_not_exist_am;
ERROR: access method "i_do_not_exist_am" does not exist
CREATE TABLE i_am_a_failure() USING "I do not exist AM";
ERROR: access method "I do not exist AM" does not exist
CREATE TABLE i_am_a_failure() USING "btree";
ERROR: access method "btree" is not of type TABLE
-- Drop table access method, which fails as objects depends on it
DROP ACCESS METHOD heap2;
ERROR: cannot drop access method heap2 because other objects depend on it

18
src/test/regress/expected/type_sanity.out
View File

@ -520,6 +520,24 @@ WHERE p1.relkind IN ('S', 'v', 'f', 'c') and
-----+---------
(0 rows)
-- Indexes should have AMs of type 'i'
SELECT pc.oid, pc.relname, pa.amname, pa.amtype
FROM pg_class as pc JOIN pg_am AS pa ON (pc.relam = pa.oid)
WHERE pc.relkind IN ('i') and
pa.amtype != 'i';
oid | relname | amname | amtype
-----+---------+--------+--------
(0 rows)
-- Tables, matviews etc should have AMs of type 't'
SELECT pc.oid, pc.relname, pa.amname, pa.amtype
FROM pg_class as pc JOIN pg_am AS pa ON (pc.relam = pa.oid)
WHERE pc.relkind IN ('r', 't', 'm') and
pa.amtype != 't';
oid | relname | amname | amtype
-----+---------+--------+--------
(0 rows)
-- **************** pg_attribute ****************
-- Look for illegal values in pg_attribute fields
SELECT p1.attrelid, p1.attname

27
src/test/regress/sql/create_am.sql
View File

@ -5,6 +5,11 @@
-- Make gist2 over gisthandler. In fact, it would be a synonym to gist.
CREATE ACCESS METHOD gist2 TYPE INDEX HANDLER gisthandler;
-- Verify return type checks for handlers
CREATE ACCESS METHOD bogus TYPE INDEX HANDLER int4in;
CREATE ACCESS METHOD bogus TYPE INDEX HANDLER heap_tableam_handler;
-- Try to create gist2 index on fast_emp4000: fail because opclass doesn't exist
CREATE INDEX grect2ind2 ON fast_emp4000 USING gist2 (home_base);
@ -72,11 +77,26 @@ DROP ACCESS METHOD gist2 CASCADE;
-- Test table access methods
--
-- prevent empty values
SET default_table_access_method = '';
-- prevent nonexistant values
SET default_table_access_method = 'I do not exist AM';
-- prevent setting it to an index AM
SET default_table_access_method = 'btree';
-- Create a heap2 table am handler with heapam handler
CREATE ACCESS METHOD heap2 TYPE TABLE HANDLER heap_tableam_handler;
-- Verify return type checks for handlers
CREATE ACCESS METHOD bogus TYPE TABLE HANDLER int4in;
CREATE ACCESS METHOD bogus TYPE TABLE HANDLER bthandler;
SELECT amname, amhandler, amtype FROM pg_am where amtype = 't' ORDER BY 1, 2;
-- First create tables employing the new AM using USING
-- plain CREATE TABLE
@ -178,6 +198,13 @@ ORDER BY 3, 1, 2;
-- don't want to keep those tables, nor the default
ROLLBACK;
-- Third, check that we can neither create a table using a nonexistant
-- AM, nor using an index AM
CREATE TABLE i_am_a_failure() USING "";
CREATE TABLE i_am_a_failure() USING i_do_not_exist_am;
CREATE TABLE i_am_a_failure() USING "I do not exist AM";
CREATE TABLE i_am_a_failure() USING "btree";
-- Drop table access method, which fails as objects depends on it
DROP ACCESS METHOD heap2;

12
src/test/regress/sql/type_sanity.sql
View File

@ -379,6 +379,18 @@ FROM pg_class as p1
WHERE p1.relkind IN ('S', 'v', 'f', 'c') and
p1.relam != 0;
-- Indexes should have AMs of type 'i'
SELECT pc.oid, pc.relname, pa.amname, pa.amtype
FROM pg_class as pc JOIN pg_am AS pa ON (pc.relam = pa.oid)
WHERE pc.relkind IN ('i') and
pa.amtype != 'i';
-- Tables, matviews etc should have AMs of type 't'
SELECT pc.oid, pc.relname, pa.amname, pa.amtype
FROM pg_class as pc JOIN pg_am AS pa ON (pc.relam = pa.oid)
WHERE pc.relkind IN ('r', 't', 'm') and
pa.amtype != 't';
-- **************** pg_attribute ****************
-- Look for illegal values in pg_attribute fields