Re: [HACKERS] dblink module printing unnamed connection (with commit acaf7ccb94)

[Peter Eisentraut]

On 3/23/17 01:38, Rushabh Lathia wrote:
> DBLINK contrib module started showing :"unnamed" connection name.

> Before this, macro used to assign the conname local variable; I quickly
> worked
> on the fix and attached patch do fix the issues. Patch assign the conname
> local variable, so that error context show the correct connection name.

Committed, thanks.

In dblink_record_internal(), I moved the conname =
text_to_cstring(PG_GETARG_TEXT_PP(0)) call a little bit, because it does
not apply in all code paths, so it could be a problem if you try to read
a text argument that the function is not actually passing in.

-- 
Peter Eisentraut  http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services


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[HACKERS] dblink module printing unnamed connection (with commit acaf7ccb94)

[Rushabh Lathia]

Hi All,

DBLINK contrib module started showing :"unnamed" connection name.

Consider the below test:

postgres=# CREATE ROLE alice NOSUPERUSER NOCREATEDB NOCREATEROLE LOGIN
PASSWORD 'wonderland';
CREATE ROLE
postgres=# GRANT EXECUTE ON FUNCTION dblink_connect_u(text,text) to alice;
GRANT
postgres=# \c postgres alice
You are now connected to database "postgres" as user "alice".
postgres=> SELECT dblink_connect_u('sm_conn_30','dbname=postgres user=alice
password=wonderland');
 dblink_connect_u
--
 OK
(1 row)

postgres=> SELECT * FROM dblink_send_query('sm_conn_30','SELECT
pg_stat_reset()') as dgr;
 dgr
-
   1
(1 row)

postgres=> SELECT * FROM dblink_get_result('sm_conn_30') AS dgr(curr_user
boolean);
ERROR:  permission denied for function pg_stat_reset
CONTEXT:  Error occurred on dblink connection named "*unnamed*": could not
execute query.

This started with below commit:

commit acaf7ccb94a3916ea83712671a3563f0eb595558
Author: Peter Eisentraut 
Date:   Sun Dec 25 12:00:00 2016 -0500

dblink: Replace some macros by static functions

Also remove some unused code and the no longer useful dblink.h file.

Reviewed-by: Tsunakawa, Takayuki 


Before this, macro used to assign the conname local variable; I quickly
worked
on the fix and attached patch do fix the issues. Patch assign the conname
local variable, so that error context show the correct connection name.


Regards,
Rushabh Lathia
www.EnterpriseDB.com
diff --git a/contrib/dblink/dblink.c b/contrib/dblink/dblink.c
index c1e9089..e42cec4 100644
--- a/contrib/dblink/dblink.c
+++ b/contrib/dblink/dblink.c
@@ -679,7 +679,7 @@ dblink_record_internal(FunctionCallInfo fcinfo, bool is_async)
 	PG_TRY();
 	{
 		char	   *sql = NULL;
-		char	   *conname = NULL;
+		char	   *conname = text_to_cstring(PG_GETARG_TEXT_PP(0));
 		bool		fail = true;	/* default to backward compatible */
 
 		if (!is_async)
@@ -687,7 +687,7 @@ dblink_record_internal(FunctionCallInfo fcinfo, bool is_async)
 			if (PG_NARGS() == 3)
 			{
 /* text,text,bool */
-dblink_get_conn(text_to_cstring(PG_GETARG_TEXT_PP(0)), , , );
+dblink_get_conn(conname, , , );
 sql = text_to_cstring(PG_GETARG_TEXT_PP(1));
 fail = PG_GETARG_BOOL(2);
 			}
@@ -702,7 +702,7 @@ dblink_record_internal(FunctionCallInfo fcinfo, bool is_async)
 }
 else
 {
-	dblink_get_conn(text_to_cstring(PG_GETARG_TEXT_PP(0)), , , );
+	dblink_get_conn(conname, , , );
 	sql = text_to_cstring(PG_GETARG_TEXT_PP(1));
 }
 			}
@@ -722,13 +722,13 @@ dblink_record_internal(FunctionCallInfo fcinfo, bool is_async)
 			if (PG_NARGS() == 2)
 			{
 /* text,bool */
-conn = dblink_get_named_conn(text_to_cstring(PG_GETARG_TEXT_PP(0)));
+conn = dblink_get_named_conn(conname);
 fail = PG_GETARG_BOOL(1);
 			}
 			else if (PG_NARGS() == 1)
 			{
 /* text */
-conn = dblink_get_named_conn(text_to_cstring(PG_GETARG_TEXT_PP(0)));
+conn = dblink_get_named_conn(conname);
 			}
 			else
 /* shouldn't happen */
@@ -1390,7 +1390,8 @@ dblink_exec(PG_FUNCTION_ARGS)
 		if (PG_NARGS() == 3)
 		{
 			/* must be text,text,bool */
-			dblink_get_conn(text_to_cstring(PG_GETARG_TEXT_PP(0)), , , );
+			conname = text_to_cstring(PG_GETARG_TEXT_PP(0));
+			dblink_get_conn(conname, , , );
 			sql = text_to_cstring(PG_GETARG_TEXT_PP(1));
 			fail = PG_GETARG_BOOL(2);
 		}
@@ -1405,7 +1406,8 @@ dblink_exec(PG_FUNCTION_ARGS)
 			}
 			else
 			{
-dblink_get_conn(text_to_cstring(PG_GETARG_TEXT_PP(0)), , , );
+conname = text_to_cstring(PG_GETARG_TEXT_PP(0));
+dblink_get_conn(conname, , , );
 sql = text_to_cstring(PG_GETARG_TEXT_PP(1));
 			}
 		}

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