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Create an improved FDW option validator function for contrib/dblink.

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dblink now has its own validator function dblink_fdw_validator(), which is
better than the core function postgresql_fdw_validator() because it gets
the list of legal options from libpq instead of having a hard-wired list.

Make the dblink extension module provide a standard foreign data wrapper
dblink_fdw that encapsulates use of this validator, and recommend use of
that wrapper instead of making up wrappers on the fly.

Unfortunately, because ad-hoc wrappers *were* recommended practice
previously, it's not clear when we can get rid of postgresql_fdw_validator
without causing upgrade problems.  But this is a step in the right
direction.

Shigeru Hanada, reviewed by KaiGai Kohei
This commit is contained in:
Tom Lane 2012-10-10 16:53:08 -04:00
parent 392b2e5010
commit 8255566f9d
9 changed files with 188 additions and 17 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
contrib/dblink/Makefile
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@ -7,7 +7,7 @@ SHLIB_LINK = $(libpq)
SHLIB_PREREQS = submake-libpq
EXTENSION = dblink
DATA = dblink--1.0.sql dblink--unpackaged--1.0.sql
DATA = dblink--1.1.sql dblink--1.0--1.1.sql dblink--unpackaged--1.0.sql
REGRESS = dblink

14
contrib/dblink/dblink--1.0--1.1.sql Normal file
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@ -0,0 +1,14 @@
/* contrib/dblink/dblink--1.0--1.1.sql */
-- complain if script is sourced in psql, rather than via CREATE EXTENSION
\echo Use "ALTER EXTENSION dblink UPDATE TO '1.1'" to load this file. \quit
CREATE FUNCTION dblink_fdw_validator(
options text[],
catalog oid
)
RETURNS void
AS 'MODULE_PATHNAME', 'dblink_fdw_validator'
LANGUAGE C STRICT;
CREATE FOREIGN DATA WRAPPER dblink_fdw VALIDATOR dblink_fdw_validator;

14
contrib/dblink/dblink--1.0.sql → contrib/dblink/dblink--1.1.sql
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@ -1,4 +1,4 @@
/* contrib/dblink/dblink--1.0.sql */
/* contrib/dblink/dblink--1.1.sql */
-- complain if script is sourced in psql, rather than via CREATE EXTENSION
\echo Use "CREATE EXTENSION dblink" to load this file. \quit
@ -221,3 +221,15 @@ CREATE FUNCTION dblink_get_notify(
RETURNS setof record
AS 'MODULE_PATHNAME', 'dblink_get_notify'
LANGUAGE C STRICT;
/* New stuff in 1.1 begins here */
CREATE FUNCTION dblink_fdw_validator(
options text[],
catalog oid
)
RETURNS void
AS 'MODULE_PATHNAME', 'dblink_fdw_validator'
LANGUAGE C STRICT;
CREATE FOREIGN DATA WRAPPER dblink_fdw VALIDATOR dblink_fdw_validator;

130
contrib/dblink/dblink.c
View File

@ -37,9 +37,12 @@
#include "libpq-fe.h"
#include "access/htup_details.h"
#include "access/reloptions.h"
#include "catalog/indexing.h"
#include "catalog/namespace.h"
#include "catalog/pg_foreign_server.h"
#include "catalog/pg_type.h"
#include "catalog/pg_user_mapping.h"
#include "executor/spi.h"
#include "foreign/foreign.h"
#include "funcapi.h"
@ -113,6 +116,8 @@ static char *escape_param_str(const char *from);
static void validate_pkattnums(Relation rel,
int2vector *pkattnums_arg, int32 pknumatts_arg,
int **pkattnums, int *pknumatts);
static bool is_valid_dblink_option(const PQconninfoOption *options,
const char *option, Oid context);
/* Global */
static remoteConn *pconn = NULL;
@ -1912,6 +1917,75 @@ dblink_get_notify(PG_FUNCTION_ARGS)
return (Datum) 0;
}
/*
* Validate the options given to a dblink foreign server or user mapping.
* Raise an error if any option is invalid.
*
* We just check the names of options here, so semantic errors in options,
* such as invalid numeric format, will be detected at the attempt to connect.
*/
PG_FUNCTION_INFO_V1(dblink_fdw_validator);
Datum
dblink_fdw_validator(PG_FUNCTION_ARGS)
{
List *options_list = untransformRelOptions(PG_GETARG_DATUM(0));
Oid context = PG_GETARG_OID(1);
ListCell *cell;
static const PQconninfoOption *options = NULL;
/*
* Get list of valid libpq options.
*
* To avoid unnecessary work, we get the list once and use it throughout
* the lifetime of this backend process. We don't need to care about
* memory context issues, because PQconndefaults allocates with malloc.
*/
if (!options)
{
options = PQconndefaults();
if (!options) /* assume reason for failure is OOM */
ereport(ERROR,
(errcode(ERRCODE_FDW_OUT_OF_MEMORY),
errmsg("out of memory"),
errdetail("could not get libpq's default connection options")));
}
/* Validate each supplied option. */
foreach(cell, options_list)
{
DefElem *def = (DefElem *) lfirst(cell);
if (!is_valid_dblink_option(options, def->defname, context))
{
/*
* Unknown option, or invalid option for the context specified,
* so complain about it. Provide a hint with list of valid
* options for the context.
*/
StringInfoData buf;
const PQconninfoOption *opt;
initStringInfo(&buf);
for (opt = options; opt->keyword; opt++)
{
if (is_valid_dblink_option(options, opt->keyword, context))
appendStringInfo(&buf, "%s%s",
(buf.len > 0) ? ", " : "",
opt->keyword);
}
ereport(ERROR,
(errcode(ERRCODE_FDW_OPTION_NAME_NOT_FOUND),
errmsg("invalid option \"%s\"", def->defname),
errhint("Valid options in this context are: %s",
buf.data)));
}
}
PG_RETURN_VOID();
}
/*************************************************************
* internal functions
*/
@ -2768,3 +2842,59 @@ validate_pkattnums(Relation rel,
errmsg("invalid attribute number %d", pkattnum)));
}
}
/*
* Check if the specified connection option is valid.
*
* We basically allow whatever libpq thinks is an option, with these
* restrictions:
* debug options: disallowed
* "client_encoding": disallowed
* "user": valid only in USER MAPPING options
* secure options (eg password): valid only in USER MAPPING options
* others: valid only in FOREIGN SERVER options
*
* We disallow client_encoding because it would be overridden anyway via
* PQclientEncoding; allowing it to be specified would merely promote
* confusion.
*/
static bool
is_valid_dblink_option(const PQconninfoOption *options, const char *option,
Oid context)
{
const PQconninfoOption *opt;
/* Look up the option in libpq result */
for (opt = options; opt->keyword; opt++)
{
if (strcmp(opt->keyword, option) == 0)
break;
}
if (opt->keyword == NULL)
return false;
/* Disallow debug options (particularly "replication") */
if (strchr(opt->dispchar, 'D'))
return false;
/* Disallow "client_encoding" */
if (strcmp(opt->keyword, "client_encoding") == 0)
return false;
/*
* If the option is "user" or marked secure, it should be specified only
* in USER MAPPING. Others should be specified only in SERVER.
*/
if (strcmp(opt->keyword, "user") == 0 || strchr(opt->dispchar, '*'))
{
if (context != UserMappingRelationId)
return false;
}
else
{
if (context != ForeignServerRelationId)
return false;
}
return true;
}

2
contrib/dblink/dblink.control
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@ -1,5 +1,5 @@
# dblink extension
comment = 'connect to other PostgreSQL databases from within a database'
default_version = '1.0'
default_version = '1.1'
module_pathname = '$libdir/dblink'
relocatable = true

1
contrib/dblink/dblink.h
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@ -58,5 +58,6 @@ extern Datum dblink_build_sql_delete(PG_FUNCTION_ARGS);
extern Datum dblink_build_sql_update(PG_FUNCTION_ARGS);
extern Datum dblink_current_query(PG_FUNCTION_ARGS);
extern Datum dblink_get_notify(PG_FUNCTION_ARGS);
extern Datum dblink_fdw_validator(PG_FUNCTION_ARGS);
#endif /* DBLINK_H */

17
contrib/dblink/expected/dblink.out
View File

@ -783,8 +783,20 @@ SELECT dblink_disconnect('dtest1');
-- test foreign data wrapper functionality
CREATE USER dblink_regression_test;
CREATE FOREIGN DATA WRAPPER postgresql;
CREATE SERVER fdtest FOREIGN DATA WRAPPER postgresql OPTIONS (dbname 'contrib_regression');
CREATE SERVER fdtest FOREIGN DATA WRAPPER dblink_fdw
OPTIONS (invalid 'val'); -- fail, invalid option
ERROR: invalid option "invalid"
HINT: Valid options in this context are: service, connect_timeout, dbname, host, hostaddr, port, application_name, fallback_application_name, keepalives, keepalives_idle, keepalives_interval, keepalives_count, sslmode, sslcompression, sslcert, sslkey, sslrootcert, sslcrl, requirepeer
CREATE SERVER fdtest FOREIGN DATA WRAPPER dblink_fdw
OPTIONS (password 'val'); -- fail, can't specify password here
ERROR: invalid option "password"
HINT: Valid options in this context are: service, connect_timeout, dbname, host, hostaddr, port, application_name, fallback_application_name, keepalives, keepalives_idle, keepalives_interval, keepalives_count, sslmode, sslcompression, sslcert, sslkey, sslrootcert, sslcrl, requirepeer
CREATE SERVER fdtest FOREIGN DATA WRAPPER dblink_fdw
OPTIONS (dbname 'contrib_regression');
CREATE USER MAPPING FOR public SERVER fdtest
OPTIONS (server 'localhost'); -- fail, can't specify server here
ERROR: invalid option "server"
HINT: Valid options in this context are: user, password
CREATE USER MAPPING FOR public SERVER fdtest;
GRANT USAGE ON FOREIGN SERVER fdtest TO dblink_regression_test;
GRANT EXECUTE ON FUNCTION dblink_connect_u(text, text) TO dblink_regression_test;
@ -823,7 +835,6 @@ REVOKE EXECUTE ON FUNCTION dblink_connect_u(text, text) FROM dblink_regression_t
DROP USER dblink_regression_test;
DROP USER MAPPING FOR public SERVER fdtest;
DROP SERVER fdtest;
DROP FOREIGN DATA WRAPPER postgresql;
-- test asynchronous notifications
SELECT dblink_connect('dbname=contrib_regression');
dblink_connect

13
contrib/dblink/sql/dblink.sql
View File

@ -361,9 +361,17 @@ SELECT dblink_disconnect('dtest1');
-- test foreign data wrapper functionality
CREATE USER dblink_regression_test;
CREATE FOREIGN DATA WRAPPER postgresql;
CREATE SERVER fdtest FOREIGN DATA WRAPPER postgresql OPTIONS (dbname 'contrib_regression');
CREATE SERVER fdtest FOREIGN DATA WRAPPER dblink_fdw
OPTIONS (invalid 'val'); -- fail, invalid option
CREATE SERVER fdtest FOREIGN DATA WRAPPER dblink_fdw
OPTIONS (password 'val'); -- fail, can't specify password here
CREATE SERVER fdtest FOREIGN DATA WRAPPER dblink_fdw
OPTIONS (dbname 'contrib_regression');
CREATE USER MAPPING FOR public SERVER fdtest
OPTIONS (server 'localhost'); -- fail, can't specify server here
CREATE USER MAPPING FOR public SERVER fdtest;
GRANT USAGE ON FOREIGN SERVER fdtest TO dblink_regression_test;
GRANT EXECUTE ON FUNCTION dblink_connect_u(text, text) TO dblink_regression_test;
@ -381,7 +389,6 @@ REVOKE EXECUTE ON FUNCTION dblink_connect_u(text, text) FROM dblink_regression_t
DROP USER dblink_regression_test;
DROP USER MAPPING FOR public SERVER fdtest;
DROP SERVER fdtest;
DROP FOREIGN DATA WRAPPER postgresql;
-- test asynchronous notifications
SELECT dblink_connect('dbname=contrib_regression');

12
doc/src/sgml/dblink.sgml
View File

@ -46,12 +46,10 @@ dblink_connect(text connname, text connstr) returns text
<para>
The connection string may also be the name of an existing foreign
server. It is recommended to use
the <function>postgresql_fdw_validator</function> when defining
the corresponding foreign-data wrapper. See the example below, as
well as the following:
server. It is recommended to use the foreign-data wrapper
<literal>dblink_fdw</literal> when defining the corresponding foreign
server. See the example below, as well as the following:
<simplelist type="inline">
<member><xref linkend="sql-createforeigndatawrapper"></member>
<member><xref linkend="sql-createserver"></member>
<member><xref linkend="sql-createusermapping"></member>
</simplelist>
@ -136,8 +134,7 @@ SELECT dblink_connect('myconn', 'dbname=postgres');
-- DETAIL: Non-superuser cannot connect if the server does not request a password.
-- HINT: Target server's authentication method must be changed.
CREATE USER dblink_regression_test WITH PASSWORD 'secret';
CREATE FOREIGN DATA WRAPPER postgresql VALIDATOR postgresql_fdw_validator;
CREATE SERVER fdtest FOREIGN DATA WRAPPER postgresql OPTIONS (hostaddr '127.0.0.1', dbname 'contrib_regression');
CREATE SERVER fdtest FOREIGN DATA WRAPPER dblink_fdw OPTIONS (hostaddr '127.0.0.1', dbname 'contrib_regression');
CREATE USER MAPPING FOR dblink_regression_test SERVER fdtest OPTIONS (user 'dblink_regression_test', password 'secret');
GRANT USAGE ON FOREIGN SERVER fdtest TO dblink_regression_test;
@ -173,7 +170,6 @@ REVOKE SELECT ON TABLE foo FROM dblink_regression_test;
DROP USER MAPPING FOR dblink_regression_test SERVER fdtest;
DROP USER dblink_regression_test;
DROP SERVER fdtest;
DROP FOREIGN DATA WRAPPER postgresql;
</screen>
</refsect1>
</refentry>