source: rtems/cpukit/libfs/src/nfsclient/src/xdr_mbuf.c @ 1e0cc86

/**
 * @file
 *
 * @brief XDR Implementation Using mbuf Buffers
 * @ingroup libfs
 *
 * xdr_mbuf is derived from xdr_mem
 */

/*
 * Author (mbuf specifica): Till Straumann <strauman@slac.stanford.edu>, 10/2002
 *
 * 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
 */

#if defined(LIBC_SCCS) && !defined(lint)
/*static char *sccsid = "from: @(#)xdr_mem.c 1.19 87/08/11 Copyr 1984 Sun Micro";*/
/*static char *sccsid = "from: @(#)xdr_mem.c    2.1 88/07/29 4.0 RPCSRC";*/
static char *rcsid = "$FreeBSD: src/lib/libc/xdr/xdr_mem.c,v 1.8 1999/08/28 00:02:56 peter Exp $";
#endif

/*
 * xdr_mbuf,  XDR implementation using mbuf buffers
 *
 * derived from:
 *
 * xdr_mem.h, XDR implementation using memory buffers.
 *
 * Copyright (C) 1984, Sun Microsystems, Inc.
 *
 * The MBUF stream is useful for BSDNET kernel (or RTEMS for that matter)
 * use.
 */

#if HAVE_CONFIG_H
#include "config.h"
#endif

#include <string.h>
#include <rpc/types.h>
#include <rpc/xdr.h>
#include <netinet/in.h>

#include <stdlib.h>

#define TODO

/* TODO remove: a hack because malloc is redefined */
#ifdef TODO
static inline void *
my_malloc(size_t i)
{
        return malloc(i);
}

static inline void
my_free(void *p)
{
        return free(p);
}
#endif

#define DEBUG_ASSERT    (1<<0)
#define DEBUG_VERB              (1<<1)

#define DEBUG                   DEBUG_ASSERT

#define _KERNEL
#include <sys/mbuf.h>

#include <assert.h>

#if DEBUG & DEBUG_VERB || defined(TODO)
#include <stdio.h>
#endif

#include "nfsclient-private.h"

static bool_t   xdrmbuf_getlong_aligned(XDR *xdrs, long *lp);
static bool_t   xdrmbuf_putlong_aligned(XDR *xdrs, const long *lp);
static bool_t   xdrmbuf_getlong_unaligned(XDR *xdrs, long *lp);
static bool_t   xdrmbuf_putlong_unaligned(XDR *xdrs, const long *lp);
static bool_t   xdrmbuf_getbytes(XDR *xdrs, caddr_t addr, u_int len);
static bool_t   xdrmbuf_putbytes(XDR *xdrs, const char *addr, u_int len);
static u_int    xdrmbuf_getpos(XDR *xdrs); /* XXX w/64-bit pointers, u_int not enough! */
static bool_t   xdrmbuf_setpos(XDR *xdrs, u_int pos);
static int32_t *xdrmbuf_inline_aligned(XDR *xdrs, u_int len);
static int32_t *xdrmbuf_inline_unaligned(XDR *xdrs, u_int len);
static void     xdrmbuf_destroy(XDR *);

static struct   xdr_ops xdrmbuf_ops_aligned = {
        xdrmbuf_getlong_aligned,
        xdrmbuf_putlong_aligned,
        xdrmbuf_getbytes,
        xdrmbuf_putbytes,
        xdrmbuf_getpos,
        xdrmbuf_setpos,
        xdrmbuf_inline_aligned,
        xdrmbuf_destroy
};

static struct   xdr_ops xdrmbuf_ops_unaligned = {
        xdrmbuf_getlong_unaligned,
        xdrmbuf_putlong_unaligned,
        xdrmbuf_getbytes,
        xdrmbuf_putbytes,
        xdrmbuf_getpos,
        xdrmbuf_setpos,
        xdrmbuf_inline_unaligned,
        xdrmbuf_destroy
};

typedef struct MBPrivateRec_ {
        struct mbuf             *mchain;
        struct mbuf             *mcurrent;
        u_int                   pos;            /* number of bytes contained in all MUBFS ahead
                                                                 * of mcurrent
                                                                 */
} MBPrivateRec, *MBPrivate;

/* NOTE: the stream position helper 'pos'
 *       must be managed by the caller!
 */
static inline void
xdrmbuf_setup(XDR *xdrs, struct mbuf *m)
{
MBPrivate       mbp = (MBPrivate)xdrs->x_base;

                mbp->mcurrent    = m;
                xdrs->x_private  = mtod(m,caddr_t);
                xdrs->x_handy    = m->m_len;
                xdrs->x_ops      = ((uintptr_t)xdrs->x_private & (sizeof(int32_t) - 1))
                                                                ? &xdrmbuf_ops_unaligned : &xdrmbuf_ops_aligned;
}

static struct mbuf *
xdrmbuf_next(XDR *xdrs)
{
struct mbuf             *rval;
MBPrivate               mbp = (MBPrivate)xdrs->x_base;

        if (mbp->mcurrent) {
                mbp->pos += mbp->mcurrent->m_len;
                rval      = mbp->mcurrent->m_next;
        } else {
                rval      = 0;
        }

        if (rval) {
                xdrmbuf_setup(xdrs, rval);
        }
#if DEBUG & DEBUG_VERB
        else {
                fprintf(stderr,"xdrmbuf: end of chain\n");
        }
#endif

        return rval;
}

/*
 * The procedure xdrmbuf_create initializes a stream descriptor for a
 * memory buffer.
 */
void
xdrmbuf_create(XDR *xdrs, struct mbuf *mbuf, enum xdr_op op)
{
MBPrivate mbp;

        xdrs->x_op = op;
        mbp = (MBPrivate)my_malloc(sizeof(*mbp));
        assert( mbp );
        xdrs->x_base  = (caddr_t) mbp;

        mbp->mchain   = mbuf;
        mbp->pos      = 0;

#if DEBUG & DEBUG_VERB
        {
        struct mbuf *mbf;
        fprintf(stderr,"Dumping chain:\n");
        for (mbf = mbuf; mbf; mbf=mbf->m_next) {
                int ii;
                fprintf(stderr,"MBUF------------");
                for (ii=0; ii<mbf->m_len; ii++) {
                        fprintf(stderr,"%02x ",mtod(mbf,char*)[ii]);
                        if (ii%16==0)
                                fputc('\n',stderr);
                }
                fputc('\n',stderr);
        }
        }
#endif

        xdrmbuf_setup(xdrs, mbuf);
}

static void
xdrmbuf_destroy(XDR *xdrs)
{
MBPrivate       mbp = (MBPrivate)xdrs->x_base;
#if 0 /* leave destroying the chain to the user */
struct mbuf *m = mbp->mchain;

        rtems_bsdnet_semaphore_obtain();
                m_freem(m);
        rtems_bsdnet_semaphore_release();
#endif

        my_free(mbp);
}

static bool_t
xdrmbuf_getlong_aligned(register XDR *xdrs, register long *lp)
{
        while ( (signed int)(xdrs->x_handy -= sizeof(int32_t)) < 0) {
                if ((xdrs->x_handy += sizeof(int32_t)) == 0) {
                        /* handy was 0 on entry; request a new buffer.
                         * Coded this way, so the most frequently executed
                         * path needs only one comparison...
                         */
                        if (!xdrmbuf_next(xdrs))
                                return FALSE;
                } else {
                        /* uh-oh an aligned long spread over two MBUFS ??
                         * let the unaligned handler deal with this rare
                         * situation.
                         */
                        return xdrmbuf_getlong_unaligned(xdrs,lp);
                }
        }
        *lp = ntohl(*(int32_t *)(xdrs->x_private));
        xdrs->x_private += sizeof(int32_t);
#if DEBUG & DEBUG_VERB
        fprintf(stderr,"Got aligned long %x\n",*lp);
#endif
        return (TRUE);
}

static bool_t
xdrmbuf_putlong_aligned(
        XDR *xdrs,
        const long *lp)
{
fprintf(stderr,"TODO: xdrmbuf_putlong_aligned() is unimplemented\n");
        return FALSE;
#if 0
        if ((xdrs->x_handy -= sizeof(int32_t)) < 0)
                return (FALSE);
        *(int32_t *)xdrs->x_private = htonl(*lp);
        xdrs->x_private += sizeof(int32_t);
        return (TRUE);
#endif
}

static bool_t
xdrmbuf_getlong_unaligned(
        XDR *xdrs,
        long *lp)
{
union {
        int32_t l;
        char    c[sizeof(int32_t)];
}       u;

register int  i,j;
register char *cp,*sp;

        i = xdrs->x_handy - sizeof(int32_t);

        /* handle the most common case first */
        if ( i >= 0 ) {

                xdrs->x_handy   = i;
                sp                          = (char*)xdrs->x_private;
                xdrs->x_private = sp + sizeof(int32_t);

#ifdef CANDO_UNALIGNED
                {
                        *lp              = ntohl(*(int32_t *)sp);
#        if DEBUG & DEBUG_VERB
                        fprintf(stderr,"Got unaligned long %x (%i remaining)\n",*lp, xdrs->x_handy);
#        endif
                        return TRUE;
                }
#else   /* machine can't do unaligned access */
                {
                        u.c[0]          = *sp;
                        u.c[1]          = *++sp;
                        u.c[2]          = *++sp;
                        u.c[3]          = *++sp;

                        goto done;
                }
#endif /* CANDO_UNALIGNED */
        }

        /* here the messy 'crossing buffers' business starts */


        j  = sizeof(int32_t);

        cp = u.c-1;

        /* NOTE: on entry to this section,  handy < j holds */
        do {
                sp = ((char*)xdrs->x_private)-1;

                if ( (i=xdrs->x_handy) >= j ) {
                        /* more data in the buffer than we need:
                         * copy everything we need and goto 'done'
                         */
                        xdrs->x_handy    = i-j;
                        do {
                                *++cp = *++sp;
                        } while (--j > 0);
                        xdrs->x_private  = (caddr_t)++sp;

                        goto done;

                } else {
                        /* not enough data - copy as much as possible
                         * then get retrieve the next MBUF and start
                         * over
                         */
                        j-=i;
                        while (i--)
                                *++cp = *++sp;
                        if (!xdrmbuf_next(xdrs))
                                return FALSE;
#if DEBUG & DEBUG_VERB
                        fprintf(stderr,"getlong_unaligned: crossed mbuf boundary\n");
#endif
                }
        } while (j > 0);

done:

        *lp = ntohl(u.l);

#if DEBUG & DEBUG_VERB
        fprintf(stderr,"Got unaligned long %x (%i remaining)\n",*lp, xdrs->x_handy);
#endif
        return (TRUE);
}

static bool_t
xdrmbuf_putlong_unaligned(
        XDR *xdrs,
        const long *lp )
{

        fprintf(stderr,"TODO: xdrmbuf_putlong_unaligned() is unimplemented\n");
        return FALSE;
#if 0
        {
        int32_t l;

        if ((xdrs->x_handy -= sizeof(int32_t)) < 0)
                return (FALSE);
        l = htonl(*lp);
        memcpy(xdrs->x_private, &l, sizeof(int32_t));
        xdrs->x_private += sizeof(int32_t);
        return (TRUE);
        }
#endif
}

static bool_t
xdrmbuf_getbytes(
        XDR *xdrs,
        caddr_t addr,
        u_int len)
{
#if DEBUG & DEBUG_VERB
int     olen=len,bufs=0;
#endif

#if DEBUG & DEBUG_VERB
        fprintf(stderr,"wanting %i bytes (have %i)\n",olen,xdrs->x_handy);
#endif

        while (len>0) {
                if (xdrs->x_handy >= len) {
                        memcpy(addr, xdrs->x_private, len);
                        xdrs->x_private += len;
                        xdrs->x_handy   -= len;
#if 0 /* save a couple of instructions */
                        len = 0;
#else
                        goto done;
#endif
                } else {
                        if (xdrs->x_handy > 0) {
                                memcpy(addr, xdrs->x_private, xdrs->x_handy);
                                len  -= xdrs->x_handy;
                                addr += xdrs->x_handy;
                        }
                        if (!xdrmbuf_next(xdrs))
                                return FALSE;
#if DEBUG & DEBUG_VERB
                        bufs++;
#endif
                }
        }
done:
#if DEBUG & DEBUG_VERB
        fprintf(stderr,"Got %i bytes (out of %i mbufs)\n",olen,bufs);
#endif
        return (TRUE);
}

static bool_t
xdrmbuf_putbytes(
        XDR *xdrs,
        const char *addr,
        u_int len )
{

        fprintf(stderr,"TODO: xdrmbuf_putbytes() is unimplemented\n");
        return FALSE;
#if 0
        if ((xdrs->x_handy -= len) < 0)
                return (FALSE);
        memcpy(xdrs->x_private, addr, len);
        xdrs->x_private += len;
        return (TRUE);
#endif
}

static u_int
xdrmbuf_getpos(
        XDR *xdrs)
{
#if 1
MBPrivate       mbp  = (MBPrivate)xdrs->x_base;
struct mbuf *m   = mbp->mcurrent;
u_int       rval = mbp->pos;

        if (m) {
                rval += xdrs->x_private - mtod(m, void*);
        }
#else
struct mbuf *m;
u_int           rval = 0;
MBPrivate       mbp  = (MBPrivate)xdrs->x_base;

        for ( m = mbp->mchain; m && m != mbp->mcurrent; m = m->m_next )
                rval += m->m_len;
        if (m) {
                rval += (u_long)xdrs->x_private - mtod(m, u_long);
        }

#endif
        return rval;
}

static bool_t
xdrmbuf_setpos(
        XDR *xdrs,
        u_int pos)
{
struct          mbuf *m;
MBPrivate       mbp   = (MBPrivate)xdrs->x_base;

        if (pos >= mbp->pos) {
                pos      -= mbp->pos;
                m         = mbp->mcurrent;
        } else {
                m         = mbp->mchain;
                mbp->pos  = 0;
        }

        while ( m && pos >= m->m_len ) {
                pos      -= m->m_len;
                mbp->pos += m->m_len;
                m         = m->m_next;
        }

        if (m) {
                xdrmbuf_setup(xdrs, m);
                xdrs->x_private += pos;
                return TRUE;
        }

        return 0 == pos ? TRUE : FALSE;
}

static int32_t *
xdrmbuf_inline_aligned(
        XDR *xdrs,
        u_int len)
{
int32_t *buf = 0;

        if (xdrs->x_handy == 0 && !xdrmbuf_next(xdrs))
                return 0;

        if (xdrs->x_handy >= len) {
                xdrs->x_handy -= len;
                buf = (int32_t *) xdrs->x_private;
                xdrs->x_private += len;
#if DEBUG & DEBUG_VERB
                fprintf(stderr,"Got %i aligned inline bytes at %x\n", len, buf);
#endif
        }
#if DEBUG & DEBUG_VERB
        else {
                fprintf(stderr,"Skipped %i aligned inline bytes\n",len);
        }
#endif
        return (buf);
}

static int32_t *
xdrmbuf_inline_unaligned(
        XDR *xdrs,
        u_int len )
{
        return (0);
}