Make path_recv() and poly_recv() reject paths/polygons containing no points.

The zero-point case is sensible so far as the data structure is concerned,
so maybe we ought to allow it sometime; but right now the textual input
routines for these types don't allow it, and it seems that not all the
functions for the types are prepared to cope.
Report and patch by Merlin Moncure.

diff --git a/src/backend/utils/adt/geo_ops.c b/src/backend/utils/adt/geo_ops.c
index 2f1714a034a4ddda87934fae931edb46a88f5b88..0efcfd60296c7e0465fdd849bd9d19fd539b2974 100644 (file)
--- a/src/backend/utils/adt/geo_ops.c
+++ b/src/backend/utils/adt/geo_ops.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/utils/adt/geo_ops.c,v 1.91 2005/10/15 02:49:28 momjian Exp $
+ *       $PostgreSQL: pgsql/src/backend/utils/adt/geo_ops.c,v 1.91.2.1 2007/12/18 00:04:22 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1456,7 +1456,7 @@ path_recv(PG_FUNCTION_ARGS)
 
        closed = pq_getmsgbyte(buf);
        npts = pq_getmsgint(buf, sizeof(int32));
-       if (npts < 0 || npts >= (int32) ((INT_MAX - offsetof(PATH, p[0])) / sizeof(Point)))
+       if (npts <= 0 || npts >= (int32) ((INT_MAX - offsetof(PATH, p[0])) / sizeof(Point)))
                ereport(ERROR,
                                (errcode(ERRCODE_INVALID_BINARY_REPRESENTATION),
                         errmsg("invalid number of points in external \"path\" value")));
@@ -3484,7 +3484,7 @@ poly_recv(PG_FUNCTION_ARGS)
        int                     size;
 
        npts = pq_getmsgint(buf, sizeof(int32));
-       if (npts < 0 || npts >= (int32) ((INT_MAX - offsetof(POLYGON, p[0])) / sizeof(Point)))
+       if (npts <= 0 || npts >= (int32) ((INT_MAX - offsetof(POLYGON, p[0])) / sizeof(Point)))
                ereport(ERROR,
                                (errcode(ERRCODE_INVALID_BINARY_REPRESENTATION),
                  errmsg("invalid number of points in external \"polygon\" value")));