Fix memory clobber problem reported by John Hansen: plperl_safe_init()

may expand the Perl stack, therefore we must SPAGAIN to reload the local
stack pointer after calling it.  Also a couple other marginal readability
improvements.

src/pl/plperl/plperl.c

@@ -33,7 +33,7 @@
  *	  ENHANCEMENTS, OR MODIFICATIONS.
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/pl/plperl/plperl.c,v 1.57 2004/11/17 21:23:36 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/pl/plperl/plperl.c,v 1.58 2004/11/18 21:35:42 tgl Exp $
  *
  **********************************************************************/
 
@@ -240,7 +240,6 @@ plperl_init_interp(void)
 	 * Initialize the proc and query hash tables
 	 ************************************************************/
 	plperl_proc_hash = newHV();
-
 }
 
 
@@ -497,10 +496,7 @@ plperl_get_elem(HV *hash, char *key)
 {
 	SV **svp = hv_fetch(hash, key, strlen(key), FALSE);
 	if (!svp)
-	{
 		elog(ERROR, "plperl: key '%s' not found", key);
-		return NULL;
-	}
 	return SvTYPE(*svp) == SVt_NULL ? NULL : SvPV(*svp, PL_na);
 }
 
@@ -659,7 +655,10 @@ plperl_create_sub(char *s, bool trusted)
 	int			count;
 
 	if (trusted && !plperl_safe_init_done)
+	{
 		plperl_safe_init();
+		SPAGAIN;
+	}
 
 	ENTER;
 	SAVETMPS;
@@ -759,12 +758,10 @@ plperl_call_perl_func(plperl_proc_desc *desc, FunctionCallInfo fcinfo)
 	PUSHMARK(SP);
 	XPUSHs(sv_2mortal(newSVpv("undef", 0)));
 	for (i = 0; i < desc->nargs; i++)
-	{
-		if (desc->arg_is_rowtype[i])
 	{
 		if (fcinfo->argnull[i])
 			XPUSHs(&PL_sv_undef);
-			else
+		else if (desc->arg_is_rowtype[i])
 		{
 			HeapTupleHeader td;
 			Oid			tupType;
@@ -782,17 +779,10 @@ plperl_call_perl_func(plperl_proc_desc *desc, FunctionCallInfo fcinfo)
 			tmptup.t_len = HeapTupleHeaderGetDatumLength(td);
 			tmptup.t_data = td;
 
-				/*
-				 * plperl_build_tuple_argument better return a mortal SV.
-				 */
+			/* plperl_build_tuple_argument better return a mortal SV */
 			hashref = plperl_build_tuple_argument(&tmptup, tupdesc);
 			XPUSHs(hashref);
 		}
-		}
-		else
-		{
-			if (fcinfo->argnull[i])
-				XPUSHs(&PL_sv_undef);
 		else
 		{
 			char	   *tmp;
@@ -805,7 +795,6 @@ plperl_call_perl_func(plperl_proc_desc *desc, FunctionCallInfo fcinfo)
 			pfree(tmp);
 		}
 	}
-	}
 	PUTBACK;
 
 	/* Do NOT use G_KEEPERR here */
@@ -848,6 +837,7 @@ plperl_call_perl_trigger_func(plperl_proc_desc *desc, FunctionCallInfo fcinfo, S
 {
 	dSP;
 	SV		   *retval;
+	Trigger    *tg_trigger;
 	int			i;
 	int			count;
 
@@ -856,8 +846,9 @@ plperl_call_perl_trigger_func(plperl_proc_desc *desc, FunctionCallInfo fcinfo, S
 
 	PUSHMARK(sp);
 	XPUSHs(td);
-	for (i = 0; i < ((TriggerData *) fcinfo->context)->tg_trigger->tgnargs; i++)
-		XPUSHs(sv_2mortal(newSVpv(((TriggerData *) fcinfo->context)->tg_trigger->tgargs[i], 0)));
+	tg_trigger = ((TriggerData *) fcinfo->context)->tg_trigger;
+	for (i = 0; i < tg_trigger->tgnargs; i++)
+		XPUSHs(sv_2mortal(newSVpv(tg_trigger->tgargs[i], 0)));
 	PUTBACK;
 
 	count = perl_call_sv(desc->reference, G_SCALAR | G_EVAL | G_KEEPERR);