Hi, Has anyone been able to consider this... This is a real issue for us working with the OR32 (OpenRisc) toolchain, so comment on the approach and/or problem itself would be appreciated. Sorry for the noise, but I don't want this to get lost. Regards, Jonas
On Wed, 2010-06-09 at 12:07 +0200, Jonas Bonn wrote:
> Casting a non-variadic function to a variadic type is not permitted in C and
> results in undefined behaviour. Although it may work for some architectures,
> on the OR32 architecture (and for others, from what I can find through
> Google),
> the parameters are passed differently depending on whether the function is
> declared varidic or not, thus casting between the two types results in
> failure.
>
> Specifically, the following is not permitted:
>
> /* Define non-variadic function */
> int foo(int x, int y) {
> ...
> }
>
> typedef int (*bar_t)(int x, int y, ...);
>
> void f() {
> int x,y;
> bar_t bar;
>
> /* Cast foo to variadic type... not allowed */
> bar = (bar_t) foo;
> (*bar)(x,y);
> }
>
> This patch redeclares the xdrproc_t to be non-variadic. None of the functions
> that are cast to xdrproc_t in uClibc are actually variadic; this applies to
> Busybox, as well.
>
> Signed-off-by: Jonas Bonn <[email protected]>
> ---
> include/rpc/xdr.h | 2 +-
> libc/inet/rpc/xdr.c | 4 ++--
> libc/inet/rpc/xdr_array.c | 4 ++--
> libc/inet/rpc/xdr_reference.c | 2 +-
> 4 files changed, 6 insertions(+), 6 deletions(-)
>
> diff --git a/include/rpc/xdr.h b/include/rpc/xdr.h
> index 9981e3a..4b663d7 100644
> --- a/include/rpc/xdr.h
> +++ b/include/rpc/xdr.h
> @@ -159,7 +159,7 @@ struct XDR
> * allocate dynamic storage of the appropriate size and return it.
> * bool_t (*xdrproc_t)(XDR *, caddr_t *);
> */
> -typedef bool_t (*xdrproc_t) (XDR *, void *,...);
> +typedef bool_t (*xdrproc_t) (XDR *, void *);
>
>
> /*
> diff --git a/libc/inet/rpc/xdr.c b/libc/inet/rpc/xdr.c
> index 78f4d04..5aec83e 100644
> --- a/libc/inet/rpc/xdr.c
> +++ b/libc/inet/rpc/xdr.c
> @@ -633,14 +633,14 @@ xdr_union (XDR *xdrs, enum_t *dscmp, char *unp, const
> struct xdr_discrim *choice
> for (; choices->proc != NULL_xdrproc_t; choices++)
> {
> if (choices->value == dscm)
> - return (*(choices->proc)) (xdrs, unp, LASTUNSIGNED);
> + return (*(choices->proc)) (xdrs, unp);
> }
>
> /*
> * no match - execute the default xdr routine if there is one
> */
> return ((dfault == NULL_xdrproc_t) ? FALSE :
> - (*dfault) (xdrs, unp, LASTUNSIGNED));
> + (*dfault) (xdrs, unp));
> }
> libc_hidden_def(xdr_union)
>
> diff --git a/libc/inet/rpc/xdr_array.c b/libc/inet/rpc/xdr_array.c
> index bb3e51e..a80e11c 100644
> --- a/libc/inet/rpc/xdr_array.c
> +++ b/libc/inet/rpc/xdr_array.c
> @@ -125,7 +125,7 @@ xdr_array (XDR *xdrs, caddr_t *addrp, u_int *sizep, u_int
> maxsize, u_int elsize,
> */
> for (i = 0; (i < c) && stat; i++)
> {
> - stat = (*elproc) (xdrs, target, LASTUNSIGNED);
> + stat = (*elproc) (xdrs, target);
> target += elsize;
> }
>
> @@ -165,7 +165,7 @@ xdr_vector (xdrs, basep, nelem, elemsize, xdr_elem)
> elptr = basep;
> for (i = 0; i < nelem; i++)
> {
> - if (!(*xdr_elem) (xdrs, elptr, LASTUNSIGNED))
> + if (!(*xdr_elem) (xdrs, elptr))
> {
> return FALSE;
> }
> diff --git a/libc/inet/rpc/xdr_reference.c b/libc/inet/rpc/xdr_reference.c
> index 937b0cc..9ef0eb4 100644
> --- a/libc/inet/rpc/xdr_reference.c
> +++ b/libc/inet/rpc/xdr_reference.c
> @@ -97,7 +97,7 @@ xdr_reference (XDR *xdrs, caddr_t *pp, u_int size,
> xdrproc_t proc)
> break;
> }
>
> - stat = (*proc) (xdrs, loc, LASTUNSIGNED);
> + stat = (*proc) (xdrs, loc);
>
> if (xdrs->x_op == XDR_FREE)
> {
--
Jonas Bonn South Pole AB
Phone : +46-8-56237100 Anderstorpsvägen 16
Mobile: +46-768-527755 SE-17154 Solna
[email protected] www.southpoleconsulting.com
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