xdr.h

Go to the documentation of this file.

/*  $Id$ */
/*      $OpenBSD: xdr.h,v 1.2 1997/09/21 10:46:18 niklas Exp $  */
/*      $NetBSD: xdr.h,v 1.7 1995/04/29 05:28:06 cgd Exp $      */

/*
 * Sun RPC is a product of Sun Microsystems, Inc. and is provided for
 * unrestricted use provided that this legend is included on all tape
 * media and as a part of the software program in whole or part.  Users
 * may copy or modify Sun RPC without charge, but are not authorized
 * to license or distribute it to anyone else except as part of a product or
 * program developed by the user.
 * 
 * SUN RPC IS PROVIDED AS IS WITH NO WARRANTIES OF ANY KIND INCLUDING THE
 * WARRANTIES OF DESIGN, MERCHANTIBILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE, OR ARISING FROM A COURSE OF DEALING, USAGE OR TRADE PRACTICE.
 * 
 * Sun RPC is provided with no support and without any obligation on the
 * part of Sun Microsystems, Inc. to assist in its use, correction,
 * modification or enhancement.
 * 
 * SUN MICROSYSTEMS, INC. SHALL HAVE NO LIABILITY WITH RESPECT TO THE
 * INFRINGEMENT OF COPYRIGHTS, TRADE SECRETS OR ANY PATENTS BY SUN RPC
 * OR ANY PART THEREOF.
 * 
 * In no event will Sun Microsystems, Inc. be liable for any lost revenue
 * or profits or other special, indirect and consequential damages, even if
 * Sun has been advised of the possibility of such damages.
 * 
 * Sun Microsystems, Inc.
 * 2550 Garcia Avenue
 * Mountain View, California  94043
 *
 *      from: @(#)xdr.h 1.19 87/04/22 SMI
 *      @(#)xdr.h       2.2 88/07/29 4.0 RPCSRC
 */

/*
 * xdr.h, External Data Representation Serialization Routines.
 *
 * Copyright (C) 1984, Sun Microsystems, Inc.
 */

#ifndef _RPC_XDR_H
#define _RPC_XDR_H
#ifndef WIN32
        #include <sys/cdefs.h>
#else
    #include "cdefs.h"
#endif

/*
 * XDR provides a conventional way for converting between C data
 * types and an external bit-string representation.  Library supplied
 * routines provide for the conversion on built-in C data types.  These
 * routines and utility routines defined here are used to help implement
 * a type encode/decode routine for each user-defined type.
 *
 * Each data type provides a single procedure which takes two arguments:
 *
 *      bool_t
 *      xdrproc(xdrs, argresp)
 *              XDR *xdrs;
 *              <type> *argresp;
 *
 * xdrs is an instance of a XDR handle, to which or from which the data
 * type is to be converted.  argresp is a pointer to the structure to be
 * converted.  The XDR handle contains an operation field which indicates
 * which of the operations (ENCODE, DECODE * or FREE) is to be performed.
 *
 * XDR_DECODE may allocate space if the pointer argresp is null.  This
 * data can be freed with the XDR_FREE operation.
 *
 * We write only one procedure per data type to make it easy
 * to keep the encode and decode procedures for a data type consistent.
 * In many cases the same code performs all operations on a user defined type,
 * because all the hard work is done in the component type routines.
 * decode as a series of calls on the nested data types.
 */

/*
 * Xdr operations.  XDR_ENCODE causes the type to be encoded into the
 * stream.  XDR_DECODE causes the type to be extracted from the stream.
 * XDR_FREE can be used to release the space allocated by an XDR_DECODE
 * request.
 */
enum xdr_op {
        XDR_ENCODE=0,
        XDR_DECODE=1,
        XDR_FREE=2
};

/*
 * This is the number of bytes per unit of external data.
 */
#define BYTES_PER_XDR_UNIT      (4)
#define RNDUP(x)  ((((x) + BYTES_PER_XDR_UNIT - 1) / BYTES_PER_XDR_UNIT) \
                    * BYTES_PER_XDR_UNIT)

/*
 * The XDR handle.
 * Contains operation which is being applied to the stream,
 * an operations vector for the paticular implementation (e.g. see xdr_mem.c),
 * and two private fields for the use of the particular impelementation.
 */
typedef struct __rpc_xdr {
        enum xdr_op     x_op;           /* operation; fast additional param */
        struct xdr_ops {
                /* get a long from underlying stream */
                bool_t  (*x_getlong) __P((struct __rpc_xdr *, long *));
                /* put a long to " */
                bool_t  (*x_putlong) __P((struct __rpc_xdr *, long *));
                /* get some bytes from " */
                bool_t  (*x_getbytes) __P((struct __rpc_xdr *, caddr_t, u_int));
                /* put some bytes to " */
                bool_t  (*x_putbytes) __P((struct __rpc_xdr *, caddr_t, u_int));
                /* returns bytes off from beginning */
                u_int   (*x_getpostn) __P((struct __rpc_xdr *));
                /* lets you reposition the stream */
                bool_t  (*x_setpostn) __P((struct __rpc_xdr *, u_int));
                /* buf quick ptr to buffered data */
                int32_t *(*x_inline) __P((struct __rpc_xdr *, u_int));
                /* free privates of this xdr_stream */
                void    (*x_destroy) __P((struct __rpc_xdr *));
        } *x_ops;
        caddr_t         x_public;       /* users' data */
        caddr_t         x_private;      /* pointer to private data */
        caddr_t         x_base;         /* private used for position info */
        int             x_handy;        /* extra private word */
} XDR;

/*
 * A xdrproc_t exists for each data type which is to be encoded or decoded.
 *
 * The second argument to the xdrproc_t is a pointer to an opaque pointer.
 * The opaque pointer generally points to a structure of the data type
 * to be decoded.  If this pointer is 0, then the type routines should
 * allocate dynamic storage of the appropriate size and return it.
 *
 * XXX can't actually prototype it, because some take three args!!!
 */
typedef bool_t (*xdrproc_t) __P((/* XDR *, void *, u_int */));

/*
 * Operations defined on a XDR handle
 *
 * XDR          *xdrs;
 * long         *longp;
 * caddr_t       addr;
 * u_int         len;
 * u_int         pos;
 */
#define XDR_GETLONG(xdrs, longp)                        \
        (*(xdrs)->x_ops->x_getlong)(xdrs, longp)
#define xdr_getlong(xdrs, longp)                        \
        (*(xdrs)->x_ops->x_getlong)(xdrs, longp)

#define XDR_PUTLONG(xdrs, longp)                        \
        (*(xdrs)->x_ops->x_putlong)(xdrs, longp)
#define xdr_putlong(xdrs, longp)                        \
        (*(xdrs)->x_ops->x_putlong)(xdrs, longp)

#define XDR_GETBYTES(xdrs, addr, len)                   \
        (*(xdrs)->x_ops->x_getbytes)(xdrs, addr, len)
#define xdr_getbytes(xdrs, addr, len)                   \
        (*(xdrs)->x_ops->x_getbytes)(xdrs, addr, len)

#define XDR_PUTBYTES(xdrs, addr, len)                   \
        (*(xdrs)->x_ops->x_putbytes)(xdrs, addr, len)
#define xdr_putbytes(xdrs, addr, len)                   \
        (*(xdrs)->x_ops->x_putbytes)(xdrs, addr, len)

#define XDR_GETPOS(xdrs)                                \
        (*(xdrs)->x_ops->x_getpostn)(xdrs)
#define xdr_getpos(xdrs)                                \
        (*(xdrs)->x_ops->x_getpostn)(xdrs)

#define XDR_SETPOS(xdrs, pos)                           \
        (*(xdrs)->x_ops->x_setpostn)(xdrs, pos)
#define xdr_setpos(xdrs, pos)                           \
        (*(xdrs)->x_ops->x_setpostn)(xdrs, pos)

#define XDR_INLINE(xdrs, len)                           \
        (*(xdrs)->x_ops->x_inline)(xdrs, len)
#define xdr_inline(xdrs, len)                           \
        (*(xdrs)->x_ops->x_inline)(xdrs, len)

#define XDR_DESTROY(xdrs)                               \
        if ((xdrs)->x_ops->x_destroy)                   \
                (*(xdrs)->x_ops->x_destroy)(xdrs)
#define xdr_destroy(xdrs)                               \
        if ((xdrs)->x_ops->x_destroy)                   \
                (*(xdrs)->x_ops->x_destroy)(xdrs)

/*
 * Support struct for discriminated unions.
 * You create an array of xdrdiscrim structures, terminated with
 * a entry with a null procedure pointer.  The xdr_union routine gets
 * the discriminant value and then searches the array of structures
 * for a matching value.  If a match is found the associated xdr routine
 * is called to handle that part of the union.  If there is
 * no match, then a default routine may be called.
 * If there is no match and no default routine it is an error.
 */
#define NULL_xdrproc_t ((xdrproc_t)0)
struct xdr_discrim {
        int     value;
        xdrproc_t proc;
};

/*
 * In-line routines for fast encode/decode of primitve data types.
 * Caveat emptor: these use single memory cycles to get the
 * data from the underlying buffer, and will fail to operate
 * properly if the data is not aligned.  The standard way to use these
 * is to say:
 *      if ((buf = XDR_INLINE(xdrs, count)) == NULL)
 *              return (FALSE);
 *      <<< macro calls >>>
 * where ``count'' is the number of bytes of data occupied
 * by the primitive data types.
 *
 * N.B. and frozen for all time: each data type here uses 4 bytes
 * of external representation.
 */
#define IXDR_GET_LONG(buf)              ((long)ntohl((u_long)*(buf)++))
#define IXDR_PUT_LONG(buf, v)           (*(buf)++ = (long)htonl((u_long)v))

#define IXDR_GET_BOOL(buf)              ((bool_t)IXDR_GET_LONG(buf))
#define IXDR_GET_ENUM(buf, t)           ((t)IXDR_GET_LONG(buf))
#define IXDR_GET_U_LONG(buf)            ((u_long)IXDR_GET_LONG(buf))
#define IXDR_GET_SHORT(buf)             ((short)IXDR_GET_LONG(buf))
#define IXDR_GET_U_SHORT(buf)           ((u_short)IXDR_GET_LONG(buf))

#define IXDR_PUT_BOOL(buf, v)           IXDR_PUT_LONG((buf), ((long)(v)))
#define IXDR_PUT_ENUM(buf, v)           IXDR_PUT_LONG((buf), ((long)(v)))
#define IXDR_PUT_U_LONG(buf, v)         IXDR_PUT_LONG((buf), ((long)(v)))
#define IXDR_PUT_SHORT(buf, v)          IXDR_PUT_LONG((buf), ((long)(v)))
#define IXDR_PUT_U_SHORT(buf, v)        IXDR_PUT_LONG((buf), ((long)(v)))

/*
 * These are the "generic" xdr routines.
 */
__BEGIN_DECLS
extern bool_t   xdr_void        __P((void));
extern bool_t   xdr_int         __P((XDR *, int *));
extern bool_t   xdr_u_int       __P((XDR *, u_int *));
extern bool_t   xdr_long        __P((XDR *, long *));
extern bool_t   xdr_u_long      __P((XDR *, u_long *));
extern bool_t   xdr_short       __P((XDR *, short *));
extern bool_t   xdr_u_short     __P((XDR *, u_short *));
extern bool_t   xdr_int16_t     __P((XDR *, int16_t *));
extern bool_t   xdr_u_int16_t   __P((XDR *, u_int16_t *));
extern bool_t   xdr_int32_t     __P((XDR *, int32_t *));
extern bool_t   xdr_u_int32_t   __P((XDR *, u_int32_t *));
extern bool_t   xdr_bool        __P((XDR *, bool_t *));
extern bool_t   xdr_enum        __P((XDR *, enum_t *));
extern bool_t   xdr_array       __P((XDR *, char **, u_int *, u_int, u_int, xdrproc_t));
extern bool_t   xdr_bytes       __P((XDR *, char **, u_int *, u_int));
extern bool_t   xdr_opaque      __P((XDR *, caddr_t, u_int));
extern bool_t   xdr_string      __P((XDR *, char **, u_int));
extern bool_t   xdr_union       __P((XDR *, enum_t *, char *, struct xdr_discrim *, xdrproc_t));
extern bool_t   xdr_char        __P((XDR *, char *));
extern bool_t   xdr_u_char      __P((XDR *, u_char *));
extern bool_t   xdr_vector      __P((XDR *, char *, u_int, u_int, xdrproc_t));
extern bool_t   xdr_float       __P((XDR *, float *));
extern bool_t   xdr_double      __P((XDR *, double *));
extern bool_t   xdr_reference   __P((XDR *, caddr_t *, u_int, xdrproc_t));
extern bool_t   xdr_pointer     __P((XDR *, caddr_t *, u_int, xdrproc_t));
extern bool_t   xdr_wrapstring  __P((XDR *, char **));
extern void     xdr_free        __P((xdrproc_t, char *));
__END_DECLS

/*
 * Common opaque bytes objects used by many rpc protocols;
 * declared here due to commonality.
 */
#define MAX_NETOBJ_SZ 1024 
struct netobj {
        u_int   n_len;
        char    *n_bytes;
};
typedef struct netobj netobj;
extern bool_t   xdr_netobj __P((XDR *, struct netobj *));

/*
 * These are the public routines for the various implementations of
 * xdr streams.
 */
__BEGIN_DECLS
/* XDR using memory buffers */
extern void   xdrmem_create     __P((XDR *, char *, u_int, enum xdr_op));

#ifdef _STDIO_H_
/* XDR using stdio library */
extern void   xdrstdio_create   __P((XDR *, FILE *, enum xdr_op));
#endif

/* XDR pseudo records for tcp */
extern void   xdrrec_create     __P((XDR *, u_int, u_int, char *,
                                    int (*) __P((caddr_t, caddr_t, int)),
                                    int (*) __P((caddr_t, caddr_t, int))));

/* make end of xdr record */
extern bool_t xdrrec_endofrecord __P((XDR *, int));

/* move to beginning of next record */
extern bool_t xdrrec_skiprecord __P((XDR *));

/* true if no more input */
extern bool_t xdrrec_eof        __P((XDR *));
__END_DECLS

#endif /* !_RPC_XDR_H */

---