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Avoid producing over-length specific_name outputs in information_schema. 

information_schema output columns that are declared as being type
sql_identifier are supposed to conform to the implementation's rules
for valid identifiers, in particular the identifier length limit.
Several places potentially violated this limit by concatenating a
function's name and OID.  (The OID is added to ensure name uniqueness
within a schema, since the spec doesn't expect function name overloading.)

Simply truncating the concatenation result to fit in "name" won't do,
since losing part of the OID might wind up giving non-unique results.
Instead, let's truncate the function name as necessary.

The most practical way to do that is to do it in a C function; the
information_schema.sql script doesn't have easy access to the value
of NAMEDATALEN, nor does it have an easy way to truncate on the basis
of resulting byte-length rather than number of characters.

(There are still a couple of places that cast concatenation results to
sql_identifier, but as far as I can see they are guaranteed not to produce
over-length strings, at least with the normal value of NAMEDATALEN.)

Discussion: https://postgr.es/m/23817.1545283477@sss.pgh.pa.us
This commit is contained in:
Tom Lane 2018-12-20 15:58:58 -05:00
parent 7b14bcc06c
commit 5bbee34d9f
4 changed files with 51 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

20
src/backend/catalog/information_schema.sql
View File

@ -416,7 +416,7 @@ CREATE VIEW check_constraint_routine_usage AS
CAST(c.conname AS sql_identifier) AS constraint_name,
CAST(current_database() AS sql_identifier) AS specific_catalog,
CAST(np.nspname AS sql_identifier) AS specific_schema,
CAST(p.proname || '_' || CAST(p.oid AS text) AS sql_identifier) AS specific_name
CAST(nameconcatoid(p.proname, p.oid) AS sql_identifier) AS specific_name
FROM pg_namespace nc, pg_constraint c, pg_depend d, pg_proc p, pg_namespace np
WHERE nc.oid = c.connamespace
AND c.contype = 'c'
@ -1115,7 +1115,7 @@ GRANT SELECT ON key_column_usage TO PUBLIC;
CREATE VIEW parameters AS
SELECT CAST(current_database() AS sql_identifier) AS specific_catalog,
CAST(n_nspname AS sql_identifier) AS specific_schema,
CAST(proname || '_' || CAST(p_oid AS text) AS sql_identifier) AS specific_name,
CAST(nameconcatoid(proname, p_oid) AS sql_identifier) AS specific_name,
CAST((ss.x).n AS cardinal_number) AS ordinal_position,
CAST(
CASE WHEN proargmodes IS NULL THEN 'IN'
@ -1320,7 +1320,7 @@ CREATE VIEW routine_privileges AS
CAST(grantee.rolname AS sql_identifier) AS grantee,
CAST(current_database() AS sql_identifier) AS specific_catalog,
CAST(n.nspname AS sql_identifier) AS specific_schema,
CAST(p.proname || '_' || CAST(p.oid AS text) AS sql_identifier) AS specific_name,
CAST(nameconcatoid(p.proname, p.oid) AS sql_identifier) AS specific_name,
CAST(current_database() AS sql_identifier) AS routine_catalog,
CAST(n.nspname AS sql_identifier) AS routine_schema,
CAST(p.proname AS sql_identifier) AS routine_name,
@ -1409,7 +1409,7 @@ GRANT SELECT ON role_routine_grants TO PUBLIC;
CREATE VIEW routines AS
SELECT CAST(current_database() AS sql_identifier) AS specific_catalog,
CAST(n.nspname AS sql_identifier) AS specific_schema,
CAST(p.proname || '_' || CAST(p.oid AS text) AS sql_identifier) AS specific_name,
CAST(nameconcatoid(p.proname, p.oid) AS sql_identifier) AS specific_name,
CAST(current_database() AS sql_identifier) AS routine_catalog,
CAST(n.nspname AS sql_identifier) AS routine_schema,
CAST(p.proname AS sql_identifier) AS routine_name,
@ -1964,7 +1964,7 @@ CREATE VIEW transforms AS
CAST(t.typname AS sql_identifier) AS udt_name,
CAST(current_database() AS sql_identifier) AS specific_catalog,
CAST(np.nspname AS sql_identifier) AS specific_schema,
CAST(p.proname || '_' || CAST(p.oid AS text) AS sql_identifier) AS specific_name,
CAST(nameconcatoid(p.proname, p.oid) AS sql_identifier) AS specific_name,
CAST(l.lanname AS sql_identifier) AS group_name,
CAST('FROM SQL' AS character_data) AS transform_type
FROM pg_type t JOIN pg_transform x ON t.oid = x.trftype
@ -1980,7 +1980,7 @@ CREATE VIEW transforms AS
CAST(t.typname AS sql_identifier) AS udt_name,
CAST(current_database() AS sql_identifier) AS specific_catalog,
CAST(np.nspname AS sql_identifier) AS specific_schema,
CAST(p.proname || '_' || CAST(p.oid AS text) AS sql_identifier) AS specific_name,
CAST(nameconcatoid(p.proname, p.oid) AS sql_identifier) AS specific_name,
CAST(l.lanname AS sql_identifier) AS group_name,
CAST('TO SQL' AS character_data) AS transform_type
FROM pg_type t JOIN pg_transform x ON t.oid = x.trftype
@ -2495,7 +2495,7 @@ CREATE VIEW view_routine_usage AS
CAST(v.relname AS sql_identifier) AS table_name,
CAST(current_database() AS sql_identifier) AS specific_catalog,
CAST(np.nspname AS sql_identifier) AS specific_schema,
CAST(p.proname || '_' || CAST(p.oid AS text) AS sql_identifier) AS specific_name
CAST(nameconcatoid(p.proname, p.oid) AS sql_identifier) AS specific_name
FROM pg_namespace nv, pg_class v, pg_depend dv,
pg_depend dp, pg_proc p, pg_namespace np
@ -2712,7 +2712,8 @@ CREATE VIEW element_types AS
UNION ALL
/* parameters */
SELECT pronamespace, CAST(proname || '_' || CAST(oid AS text) AS sql_identifier),
SELECT pronamespace,
CAST(nameconcatoid(proname, oid) AS sql_identifier),
'ROUTINE'::text, (ss.x).n, (ss.x).x, 0
FROM (SELECT p.pronamespace, p.proname, p.oid,
_pg_expandarray(coalesce(p.proallargtypes, p.proargtypes::oid[])) AS x
@ -2721,7 +2722,8 @@ CREATE VIEW element_types AS
UNION ALL
/* result types */
SELECT p.pronamespace, CAST(p.proname || '_' || CAST(p.oid AS text) AS sql_identifier),
SELECT p.pronamespace,
CAST(nameconcatoid(p.proname, p.oid) AS sql_identifier),
'ROUTINE'::text, 0, p.prorettype, 0
FROM pg_proc p

35
src/backend/utils/adt/name.c
View File

@ -364,3 +364,38 @@ current_schemas(PG_FUNCTION_ARGS)
PG_RETURN_POINTER(array);
}
/*
* SQL-function nameconcatoid(name, oid) returns name
*
* This is used in the information_schema to produce specific_name columns,
* which are supposed to be unique per schema. We achieve that (in an ugly
* way) by appending the object's OID. The result is the same as
* ($1::text || '_' || $2::text)::name
* except that, if it would not fit in NAMEDATALEN, we make it do so by
* truncating the name input (not the oid).
*/
Datum
nameconcatoid(PG_FUNCTION_ARGS)
{
Name nam = PG_GETARG_NAME(0);
Oid oid = PG_GETARG_OID(1);
Name result;
char suffix[20];
int suflen;
int namlen;
suflen = snprintf(suffix, sizeof(suffix), "_%u", oid);
namlen = strlen(NameStr(*nam));
/* Truncate oversize input by truncating name part, not suffix */
if (namlen + suflen >= NAMEDATALEN)
namlen = pg_mbcliplen(NameStr(*nam), namlen, NAMEDATALEN - 1 - suflen);
/* We use palloc0 here to ensure result is zero-padded */
result = (Name) palloc0(NAMEDATALEN);
memcpy(NameStr(*result), NameStr(*nam), namlen);
memcpy(NameStr(*result) + namlen, suffix, suflen);
PG_RETURN_NAME(result);
}

2
src/include/catalog/catversion.h
View File

@ -53,6 +53,6 @@
*/
/* yyyymmddN */
#define CATALOG_VERSION_NO 201812192
#define CATALOG_VERSION_NO 201812201
#endif

4
src/include/catalog/pg_proc.dat
View File

@ -716,6 +716,10 @@
proname => 'bttextnamecmp', proleakproof => 't', prorettype => 'int4',
proargtypes => 'text name', prosrc => 'bttextnamecmp' },
{ oid => '266', descr => 'concatenate name and oid',
proname => 'nameconcatoid', prorettype => 'name', proargtypes => 'name oid',
prosrc => 'nameconcatoid' },
{ oid => '274',
descr => 'current date and time - increments during transactions',
proname => 'timeofday', provolatile => 'v', prorettype => 'text',