pg_trigger.tgargs needs detoast

   Hello,

   This patch fixes a bug of case of extraction of pg_trigger.tgargs.
   There was a problem when we used a long argument in defining trigger,
possibly resulting in a server crash.

Example:

   We defined a CREATE TRIGGER such as follows and registered trigger.
   In this case, the argument value which we received in the trigger
procedure was not right.

CREATE TRIGGER trigger_test BEFORE INSERT OR UPDATE ON sample FOR EACH
ROW EXECUTE PROCEDURE sample_trig('XXX...(more than 1823 characters)');

   The trigger procedure which receives the argument:

Datum sample_trig(PG_FUNCTION_ARGS)
{
     TriggerData* trigdata = (TriggerData*)fcinfo->context;
     char** args = trigdata->tg_trigger->tgargs;
     int nargs = trigdata->tg_trigger->tgnargs;

     int i;
     for (i = 0; i < nargs; i++) {
         elog(LOG, "%s", args[i]);
     }
     ...
}

Result:

   Before: LOG: (the character that is not right, for example '%')
   After : LOG: XXX...(more than 1823 characters)

Regards,

---
Kenji Kawamura
NTT Open Source Center, Japan
Index: src/backend/commands/tablecmds.c
===================================================================
--- src/backend/commands/tablecmds.c    (HEAD)
+++ src/backend/commands/tablecmds.c    (modified)
@@ -1800,8 +1800,7 @@
          * line; so does trigger.c ...
          */
         tgnargs = pg_trigger->tgnargs;
-        val = (bytea *)
-            DatumGetPointer(fastgetattr(tuple,
+        val = DatumGetByteaP(fastgetattr(tuple,
                                         Anum_pg_trigger_tgargs,
                                         tgrel->rd_att, &isnull));
         if (isnull || tgnargs < RI_FIRST_ATTNAME_ARGNO ||
Index: src/backend/commands/trigger.c
===================================================================
--- src/backend/commands/trigger.c    (HEAD)
+++ src/backend/commands/trigger.c    (modified)
@@ -906,8 +906,7 @@
             char       *p;
             int            i;

-            val = (bytea *)
-                DatumGetPointer(fastgetattr(htup,
+            val = DatumGetByteaP(fastgetattr(htup,
                                             Anum_pg_trigger_tgargs,
                                             tgrel->rd_att, &isnull));
             if (isnull)
Index: src/backend/utils/adt/ruleutils.c
===================================================================
--- src/backend/utils/adt/ruleutils.c    (HEAD)
+++ src/backend/utils/adt/ruleutils.c    (modified)
@@ -521,8 +521,7 @@
         char       *p;
         int            i;

-        val = (bytea *)
-            DatumGetPointer(fastgetattr(ht_trig,
+        val = DatumGetByteaP(fastgetattr(ht_trig,
                                         Anum_pg_trigger_tgargs,
                                         tgrel->rd_att, &isnull));
         if (isnull)