Fix potentially-unportable code in contrib/adminpack.

Spelling access(2)'s second argument as "2" is just horrid.
POSIX makes no promises as to the numeric values of W_OK and related
macros.  Even if it accidentally works as intended on every supported
platform, it's still unreadable and inconsistent with adjacent code.

In passing, don't spell "NULL" as "0" either.  Yes, that's legal C;
no, it's not project style.

Back-patch, just in case the unportability is real and not theoretical.
(Most likely, even if a platform had different bit assignments for
access()'s modes, there'd not be an observable behavior difference
here; but I'm being paranoid today.)

diff --git a/contrib/adminpack/adminpack.c b/contrib/adminpack/adminpack.c
index f3f8e7f1e41ec1033a9c939064c1dc640fc45352..f1ae4b8285af805a1fc415d863a48f5f2328e991 100644 (file)
--- a/contrib/adminpack/adminpack.c
+++ b/contrib/adminpack/adminpack.c
@@ -173,7 +173,7 @@ pg_file_rename(PG_FUNCTION_ARGS)
        fn1 = convert_and_check_filename(PG_GETARG_TEXT_PP(0), false);
        fn2 = convert_and_check_filename(PG_GETARG_TEXT_PP(1), false);
        if (PG_ARGISNULL(2))
-               fn3 = 0;
+               fn3 = NULL;
        else
                fn3 = convert_and_check_filename(PG_GETARG_TEXT_PP(2), false);
 
@@ -195,7 +195,7 @@ pg_file_rename(PG_FUNCTION_ARGS)
                PG_RETURN_BOOL(false);
        }
 
-       rc = access(fn3 ? fn3 : fn2, 2);
+       rc = access(fn3 ? fn3 : fn2, W_OK);
        if (rc >= 0 || errno != ENOENT)
        {
                ereport(ERROR,