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Commit816ff27

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Reject zero or negative BY step in plpgsql integer FOR-loops, and behave
sanely if the loop value overflows int32 on the way to the end value.Avoid useless computation of "SELECT 1" when BY is omitted. Avoid sometype-punning between Datum and int4 that dates from the original coding.
1 parenta69f902 commit816ff27

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4 files changed

+68
-58
lines changed

4 files changed

+68
-58
lines changed

‎src/pl/plpgsql/src/gram.y‎

Lines changed: 11 additions & 25 deletions
Original file line numberDiff line numberDiff line change
@@ -9,7 +9,7 @@
99
*
1010
*
1111
* IDENTIFICATION
12-
* $PostgreSQL: pgsql/src/pl/plpgsql/src/gram.y,v 1.102 2007/04/29 01:21:09 neilc Exp $
12+
* $PostgreSQL: pgsql/src/pl/plpgsql/src/gram.y,v 1.103 2007/07/15 02:15:04 tgl Exp $
1313
*
1414
*-------------------------------------------------------------------------
1515
*/
@@ -876,7 +876,7 @@ stmt_for: opt_block_label K_FOR for_control loop_body
876876
}
877877

878878
check_labels($1, $4.end_label);
879-
/* close namespace started inopt_label*/
879+
/* close namespace started inopt_block_label*/
880880
plpgsql_ns_pop();
881881
}
882882
;
@@ -968,39 +968,25 @@ for_control:
968968
PLpgSQL_stmt_fori*new;
969969
char*varname;
970970

971-
/*First expression is well-formed*/
971+
/*Check first expression is well-formed*/
972972
check_sql_expr(expr1->query);
973973

974-
975-
expr2 = read_sql_construct(K_BY,
976-
K_LOOP,
974+
/* Read and check the second one*/
975+
expr2 = read_sql_construct(K_LOOP,
976+
K_BY,
977977
"LOOP",
978978
"SELECT",
979979
true,
980-
false,
980+
true,
981981
&tok);
982982

983+
/* Get the BY clause if any*/
983984
if (tok == K_BY)
984985
expr_by = plpgsql_read_expression(K_LOOP,"LOOP");
985986
else
986-
{
987-
/*
988-
* If there is no BY clause we will assume 1
989-
*/
990-
char buf[1024];
991-
PLpgSQL_dstringds;
992-
993-
plpgsql_dstring_init(&ds);
994-
995-
expr_by = palloc0(sizeof(PLpgSQL_expr));
996-
expr_by->dtype = PLPGSQL_DTYPE_EXPR;
997-
strcpy(buf,"SELECT 1");
998-
plpgsql_dstring_append(&ds, buf);
999-
expr_by->query = pstrdup(plpgsql_dstring_get(&ds));
1000-
expr_by->plan=NULL;
1001-
}
987+
expr_by =NULL;
1002988

1003-
/*should have had a single variable name*/
989+
/*Should have had a single variable name*/
1004990
plpgsql_error_lineno =$2.lineno;
1005991
if ($2.scalar &&$2.row)
1006992
ereport(ERROR,
@@ -1023,7 +1009,7 @@ for_control:
10231009
new->reverse = reverse;
10241010
new->lower = expr1;
10251011
new->upper = expr2;
1026-
new->by = expr_by;
1012+
new->step = expr_by;
10271013

10281014
$$ = (PLpgSQL_stmt *)new;
10291015
}

‎src/pl/plpgsql/src/pl_exec.c‎

Lines changed: 52 additions & 28 deletions
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,7 @@
88
*
99
*
1010
* IDENTIFICATION
11-
* $PostgreSQL: pgsql/src/pl/plpgsql/src/pl_exec.c,v 1.197 2007/06/05 21:31:08 tgl Exp $
11+
* $PostgreSQL: pgsql/src/pl/plpgsql/src/pl_exec.c,v 1.198 2007/07/15 02:15:04 tgl Exp $
1212
*
1313
*-------------------------------------------------------------------------
1414
*/
@@ -1517,25 +1517,26 @@ exec_stmt_while(PLpgSQL_execstate *estate, PLpgSQL_stmt_while *stmt)
15171517
/* ----------
15181518
* exec_stmt_foriIterate an integer variable
15191519
*from a lower to an upper value
1520-
*incrementing or decrementing in BY value
1521-
*Loop can be left with exit.
1520+
*incrementing or decrementing by the BY value
15221521
* ----------
15231522
*/
15241523
staticint
15251524
exec_stmt_fori(PLpgSQL_execstate*estate,PLpgSQL_stmt_fori*stmt)
15261525
{
15271526
PLpgSQL_var*var;
15281527
Datumvalue;
1529-
Datumby_value;
1530-
Oidvaltype;
15311528
boolisnull;
1529+
Oidvaltype;
1530+
int32loop_value;
1531+
int32end_value;
1532+
int32step_value;
15321533
boolfound= false;
15331534
intrc=PLPGSQL_RC_OK;
15341535

15351536
var= (PLpgSQL_var*) (estate->datums[stmt->var->varno]);
15361537

15371538
/*
1538-
* Get the value of the lower bound into the loop var
1539+
* Get the value of the lower bound
15391540
*/
15401541
value=exec_eval_expr(estate,stmt->lower,&isnull,&valtype);
15411542
value=exec_cast_value(value,valtype,var->datatype->typoid,
@@ -1546,8 +1547,7 @@ exec_stmt_fori(PLpgSQL_execstate *estate, PLpgSQL_stmt_fori *stmt)
15461547
ereport(ERROR,
15471548
(errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED),
15481549
errmsg("lower bound of FOR loop cannot be NULL")));
1549-
var->value=value;
1550-
var->isnull= false;
1550+
loop_value=DatumGetInt32(value);
15511551
exec_eval_cleanup(estate);
15521552

15531553
/*
@@ -1562,44 +1562,60 @@ exec_stmt_fori(PLpgSQL_execstate *estate, PLpgSQL_stmt_fori *stmt)
15621562
ereport(ERROR,
15631563
(errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED),
15641564
errmsg("upper bound of FOR loop cannot be NULL")));
1565+
end_value=DatumGetInt32(value);
15651566
exec_eval_cleanup(estate);
15661567

15671568
/*
1568-
* Get theby value
1569+
* Get thestep value
15691570
*/
1570-
by_value=exec_eval_expr(estate,stmt->by,&isnull,&valtype);
1571-
by_value=exec_cast_value(by_value,valtype,var->datatype->typoid,
1572-
&(var->datatype->typinput),
1573-
var->datatype->typioparam,
1574-
var->datatype->atttypmod,isnull);
1575-
1576-
if (isnull)
1577-
ereport(ERROR,
1578-
(errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED),
1579-
errmsg("by value of FOR loop cannot be NULL")));
1580-
exec_eval_cleanup(estate);
1571+
if (stmt->step)
1572+
{
1573+
value=exec_eval_expr(estate,stmt->step,&isnull,&valtype);
1574+
value=exec_cast_value(value,valtype,var->datatype->typoid,
1575+
&(var->datatype->typinput),
1576+
var->datatype->typioparam,
1577+
var->datatype->atttypmod,isnull);
1578+
if (isnull)
1579+
ereport(ERROR,
1580+
(errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED),
1581+
errmsg("BY value of FOR loop cannot be NULL")));
1582+
step_value=DatumGetInt32(value);
1583+
exec_eval_cleanup(estate);
1584+
if (step_value <=0)
1585+
ereport(ERROR,
1586+
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
1587+
errmsg("BY value of FOR loop must be greater than zero")));
1588+
}
1589+
else
1590+
step_value=1;
15811591

15821592
/*
15831593
* Now do the loop
15841594
*/
15851595
for (;;)
15861596
{
15871597
/*
1588-
* Checkbounds
1598+
* Checkagainst upper bound
15891599
*/
15901600
if (stmt->reverse)
15911601
{
1592-
if ((int4) (var->value)< (int4)value)
1602+
if (loop_value<end_value)
15931603
break;
15941604
}
15951605
else
15961606
{
1597-
if ((int4) (var->value)> (int4)value)
1607+
if (loop_value>end_value)
15981608
break;
15991609
}
16001610

16011611
found= true;/* looped at least once */
16021612

1613+
/*
1614+
* Assign current value to loop var
1615+
*/
1616+
var->value=Int32GetDatum(loop_value);
1617+
var->isnull= false;
1618+
16031619
/*
16041620
* Execute the statements
16051621
*/
@@ -1625,13 +1641,12 @@ exec_stmt_fori(PLpgSQL_execstate *estate, PLpgSQL_stmt_fori *stmt)
16251641
* current statement's label, if any: return RC_EXIT so that the
16261642
* EXIT continues to propagate up the stack.
16271643
*/
1628-
16291644
break;
16301645
}
16311646
elseif (rc==PLPGSQL_RC_CONTINUE)
16321647
{
16331648
if (estate->exitlabel==NULL)
1634-
/*anonymous continue, so re-run the current loop */
1649+
/*unlabelled continue, so re-run the current loop */
16351650
rc=PLPGSQL_RC_OK;
16361651
elseif (stmt->label!=NULL&&
16371652
strcmp(stmt->label,estate->exitlabel)==0)
@@ -1652,12 +1667,21 @@ exec_stmt_fori(PLpgSQL_execstate *estate, PLpgSQL_stmt_fori *stmt)
16521667
}
16531668

16541669
/*
1655-
* Increase/decrease loop var
1670+
* Increase/decrease loop value, unless it would overflow, in which
1671+
* case exit the loop.
16561672
*/
16571673
if (stmt->reverse)
1658-
var->value-=by_value;
1674+
{
1675+
if ((int32) (loop_value-step_value)>loop_value)
1676+
break;
1677+
loop_value-=step_value;
1678+
}
16591679
else
1660-
var->value+=by_value;
1680+
{
1681+
if ((int32) (loop_value+step_value)<loop_value)
1682+
break;
1683+
loop_value+=step_value;
1684+
}
16611685
}
16621686

16631687
/*

‎src/pl/plpgsql/src/pl_funcs.c‎

Lines changed: 3 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,7 @@
88
*
99
*
1010
* IDENTIFICATION
11-
* $PostgreSQL: pgsql/src/pl/plpgsql/src/pl_funcs.c,v 1.59 2007/04/29 01:21:09 neilc Exp $
11+
* $PostgreSQL: pgsql/src/pl/plpgsql/src/pl_funcs.c,v 1.60 2007/07/15 02:15:04 tgl Exp $
1212
*
1313
*-------------------------------------------------------------------------
1414
*/
@@ -701,8 +701,8 @@ dump_fori(PLpgSQL_stmt_fori *stmt)
701701
dump_expr(stmt->upper);
702702
printf("\n");
703703
dump_ind();
704-
printf("by = ");
705-
dump_expr(stmt->by);
704+
printf("step = ");
705+
dump_expr(stmt->step);
706706
printf("\n");
707707
dump_indent-=2;
708708

‎src/pl/plpgsql/src/plpgsql.h‎

Lines changed: 2 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,7 @@
88
*
99
*
1010
* IDENTIFICATION
11-
* $PostgreSQL: pgsql/src/pl/plpgsql/src/plpgsql.h,v 1.88 2007/04/29 01:21:09 neilc Exp $
11+
* $PostgreSQL: pgsql/src/pl/plpgsql/src/plpgsql.h,v 1.89 2007/07/15 02:15:04 tgl Exp $
1212
*
1313
*-------------------------------------------------------------------------
1414
*/
@@ -402,7 +402,7 @@ typedef struct
402402
PLpgSQL_var*var;
403403
PLpgSQL_expr*lower;
404404
PLpgSQL_expr*upper;
405-
PLpgSQL_expr*by;
405+
PLpgSQL_expr*step;/* NULL means default (ie, BY 1) */
406406
intreverse;
407407
List*body;/* List of statements */
408408
}PLpgSQL_stmt_fori;

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