Slightly amended version of the proposed patch for

"[perl #22390] export PERLIO=bytes segfaults";
the amendment is to set errno.
TODO: we really should not get here if the layer
stack is corrupt or non-sensical (like "bytes").

p4raw-id: //depot/perl@19747

diff --git a/perlio.c b/perlio.c
index 91db1e1..38db370 100644 (file)
--- a/perlio.c
+++ b/perlio.c
@@ -3421,8 +3421,10 @@ PerlIOBuf_open(pTHX_ PerlIO_funcs *self, PerlIO_list_t *layers,
             * mode++;
             */
        }
-       f = (*tab->Open) (aTHX_ tab, layers, n - 1, mode, fd, imode, perm,
-                         f, narg, args);
+       f = tab && tab->Open ?
+         (*tab->Open) (aTHX_ tab, layers, n - 1, mode, fd, imode, perm,
+                       f, narg, args)
+         : Nullfp;
        if (f) {
            if (PerlIO_push(aTHX_ f, self, mode, PerlIOArg) == 0) {
                /*
@@ -3451,6 +3453,8 @@ PerlIOBuf_open(pTHX_ PerlIO_funcs *self, PerlIO_list_t *layers,
 #endif
            }
        }
+       else
+           SETERRNO(EINVAL, SS_IVCHAN);
     }
     return f;
 }