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)
---------------------------(end of broadcast)---------------------------
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