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/projects/cubeos/src_current/net/rpc/xdr_rec.c

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/* @(#)xdr_rec.c        2.2 88/08/01 4.0 RPCSRC */
/*
 * 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(lint) && defined(SCCSIDS)
static char sccsid[] = "@(#)xdr_rec.c 1.21 87/08/11 Copyr 1984 Sun Micro";
#endif

/*
 * xdr_rec.c, Implements TCP/IP based XDR streams with a "record marking"
 * layer above tcp (for rpc's use).
 *
 * Copyright (C) 1984, Sun Microsystems, Inc.
 *
 * These routines interface XDRSTREAMS to a tcp/ip connection.
 * There is a record marking layer between the xdr stream
 * and the tcp transport level.  A record is composed on one or more
 * record fragments.  A record fragment is a thirty-two bit header followed
 * by n bytes of data, where n is contained in the header.  The header
 * is represented as a htonl(u_long).  Thegh order bit encodes
 * whether or not the fragment is the last fragment of the record
 * (1 => fragment is last, 0 => more fragments to follow. 
 * The other 31 bits encode the byte length of the fragment.
 */

#include <stdio.h>
#include <rpc/types.h>
#include <rpc/xdr.h>
#include <netinet/in.h>
#include <string.h>             /* CUBEOS: for bcopy */

extern long lseek ();

static u_int fix_buf_size ();

static bool_t xdrrec_getlong ();
static bool_t xdrrec_putlong ();
static bool_t xdrrec_getbytes ();
static bool_t xdrrec_putbytes ();
static u_int xdrrec_getpos ();
static bool_t xdrrec_setpos ();
static long *xdrrec_inline ();
static void xdrrec_destroy ();

static struct xdr_ops xdrrec_ops =
{
        xdrrec_getlong,
        xdrrec_putlong,
        xdrrec_getbytes,
        xdrrec_putbytes,
        xdrrec_getpos,
        xdrrec_setpos,
        xdrrec_inline,
        xdrrec_destroy
};

/*
 * A record is composed of one or more record fragments.
 * A record fragment is a two-byte header followed by zero to
 * 2**32-1 bytes.  The header is treated as a long unsigned and is
 * encode/decoded to the network via htonl/ntohl.  The low order 31 bits
 * are a byte count of the fragment.  The highest order bit is a boolean:
 * 1 => this fragment is the last fragment of the record,
 * 0 => this fragment is followed by more fragment(s).
 *
 * The fragment/record machinery is not general;  it is constructed to
 * meet the needs of xdr and rpc based on tcp.
 */

#define LAST_FRAG ((u_long)(1 << 31))

typedef struct rec_strm {
        caddr_t tcp_handle;
        caddr_t the_buffer;
        /*
         * out-goung bits
         */
        int (*writeit) ();
        caddr_t out_base;       /* output buffer (points to frag header) */
        caddr_t out_finger;     /* next output position */
        caddr_t out_boundry;    /* data cannot up to this address */
        u_long *frag_header;    /* beginning of curren fragment */
        bool_t frag_sent;       /* true if buffer sent in middle of record */
        /*
         * in-coming bits
         */
        int (*readit) ();
        u_long in_size;         /* fixed size of the input buffer */
        caddr_t in_base;
        caddr_t in_finger;      /* location of next byte to be had */
        caddr_t in_boundry;     /* can read up to this location */
        long fbtbc;             /* fragment bytes to be consumed */
        bool_t last_frag;
        u_int sendsize;
        u_int recvsize;
} RECSTREAM;


/*
 * Create an xdr handle for xdrrec
 * xdrrec_create fills in xdrs.  Sendsize and recvsize are
 * send and recv buffer sizes (0 => use default).
 * tcp_handle is an opaque handle that is passed as the first parameter to
 * the procedures readit and writeit.  Readit and writeit are read and
 * write respectively.   They are like the system
 * calls expect that they take an opaque handle rather than an fd.
 */
void xdrrec_create (xdrs, sendsize, recvsize, tcp_handle, readit, writeit)
     register XDR *xdrs;
     register u_int sendsize;
     register u_int recvsize;
     caddr_t tcp_handle;
     int (*readit) ();          /* like read, but pass it a tcp_handle, not sock */
     int (*writeit) ();         /* like write, but pass it a tcp_handle, not sock */
{
        register RECSTREAM *rstrm =
        (RECSTREAM *) mem_alloc (sizeof (RECSTREAM));

        if (rstrm == NULL) {
                (void) fprintf (stderr, "xdrrec_create: out of memory\n");
                /* 
                 *  This is bad.  Should rework xdrrec_create to 
                 *  return a handle, and in this case return NULL
                 */
                return;
        }
        /*
         * adjust sizes and allocate buffer quad byte aligned
         */
        rstrm->sendsize = sendsize = fix_buf_size (sendsize);
        rstrm->recvsize = recvsize = fix_buf_size (recvsize);
        rstrm->the_buffer = mem_alloc (sendsize + recvsize + BYTES_PER_XDR_UNIT);
        if (rstrm->the_buffer == NULL) {
                (void) fprintf (stderr, "xdrrec_create: out of memory\n");
                return;
        }
        for (rstrm->out_base = rstrm->the_buffer;
             (u_int) rstrm->out_base % BYTES_PER_XDR_UNIT != 0;
             rstrm->out_base++);
        rstrm->in_base = rstrm->out_base + sendsize;
        /*
         * now the rest ...
         */
        xdrs->x_ops = &xdrrec_ops;
        xdrs->x_private = (caddr_t) rstrm;
        rstrm->tcp_handle = tcp_handle;
        rstrm->readit = readit;
        rstrm->writeit = writeit;
        rstrm->out_finger = rstrm->out_boundry = rstrm->out_base;
        rstrm->frag_header = (u_long *) rstrm->out_base;
        rstrm->out_finger += sizeof (u_long);
        rstrm->out_boundry += sendsize;
        rstrm->frag_sent = FALSE;
        rstrm->in_size = recvsize;
        rstrm->in_boundry = rstrm->in_base;
        rstrm->in_finger = (rstrm->in_boundry += recvsize);
        rstrm->fbtbc = 0;
        rstrm->last_frag = TRUE;
}


/*
 * The reoutines defined below are the xdr ops which will go into the
 * xdr handle filled in by xdrrec_create.
 */

static bool_t
  xdrrec_getlong (xdrs, lp)
     XDR *xdrs;
     long *lp;
{
        register RECSTREAM *rstrm = (RECSTREAM *) (xdrs->x_private);
        register long *buflp = (long *) (rstrm->in_finger);
        long mylong;

        /* first try the inline, fast case */
        if ((rstrm->fbtbc >= sizeof (long)) &&
              (((int) rstrm->in_boundry - (int) buflp) >= sizeof (long))) {
                *lp = (long) ntohl ((u_long) (*buflp));
                rstrm->fbtbc -= sizeof (long);
                rstrm->in_finger += sizeof (long);
        } else {
                if (!xdrrec_getbytes (xdrs, (caddr_t) & mylong, sizeof (long)))
                          return (FALSE);
                *lp = (long) ntohl ((u_long) mylong);
        }
        return (TRUE);
}

static bool_t
  xdrrec_putlong (xdrs, lp)
     XDR *xdrs;
     long *lp;
{
        register RECSTREAM *rstrm = (RECSTREAM *) (xdrs->x_private);
        register long *dest_lp = ((long *) (rstrm->out_finger));

        if ((rstrm->out_finger += sizeof (long)) > rstrm->out_boundry) {
                /*
                 * this case should almost never happen so the code is
                 * inefficient
                 */
                rstrm->out_finger -= sizeof (long);
                rstrm->frag_sent = TRUE;
                if (!flush_out (rstrm, FALSE))
                        return (FALSE);
                dest_lp = ((long *) (rstrm->out_finger));
                rstrm->out_finger += sizeof (long);
        }
        *dest_lp = (long) htonl ((u_long) (*lp));
        return (TRUE);
}

static bool_t                   /* must manage buffers, fragments, and records */
  xdrrec_getbytes (xdrs, addr, len)
     XDR *xdrs;
     register caddr_t addr;
     register u_int len;
{
        register RECSTREAM *rstrm = (RECSTREAM *) (xdrs->x_private);
        register int current;

        while (len > 0) {
                current = rstrm->fbtbc;
                if (current == 0) {
                        if (rstrm->last_frag)
                                return (FALSE);
                        if (!set_input_fragment (rstrm))
                                return (FALSE);
                        continue;
                }
                current = (len < current) ? len : current;
                if (!get_input_bytes (rstrm, addr, current))
                        return (FALSE);
                addr += current;
                rstrm->fbtbc -= current;
                len -= current;
        }
        return (TRUE);
}

static bool_t
  xdrrec_putbytes (xdrs, addr, len)
     XDR *xdrs;
     register caddr_t addr;
     register u_int len;
{
        register RECSTREAM *rstrm = (RECSTREAM *) (xdrs->x_private);
        register int current;

        while (len > 0) {
                current = (u_int) rstrm->out_boundry - (u_int) rstrm->out_finger;
                current = (len < current) ? len : current;
                bcopy (addr, rstrm->out_finger, current);
                rstrm->out_finger += current;
                addr += current;
                len -= current;
                if (rstrm->out_finger == rstrm->out_boundry) {
                        rstrm->frag_sent = TRUE;
                        if (!flush_out (rstrm, FALSE))
                                return (FALSE);
                }
        }
        return (TRUE);
}

static u_int
  xdrrec_getpos (xdrs)
     register XDR *xdrs;
{
        register RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
        register long pos;

        pos = lseek ((int) rstrm->tcp_handle, (long) 0, 1);
        if (pos != -1)
                switch (xdrs->x_op) {

                case XDR_ENCODE:
                        pos += rstrm->out_finger - rstrm->out_base;
                        break;

                case XDR_DECODE:
                        pos -= rstrm->in_boundry - rstrm->in_finger;
                        break;

                default:
                        pos = (u_int) - 1;
                        break;
                }
        return ((u_int) pos);
}

static bool_t
  xdrrec_setpos (xdrs, pos)
     register XDR *xdrs;
     u_int pos;
{
        register RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
        u_int currpos = xdrrec_getpos (xdrs);
        int delta = currpos - pos;
        caddr_t newpos;

        if ((int) currpos != -1)
                switch (xdrs->x_op) {

                case XDR_ENCODE:
                        newpos = rstrm->out_finger - delta;
                        if ((newpos > (caddr_t) (rstrm->frag_header)) &&
                            (newpos < rstrm->out_boundry)) {
                                rstrm->out_finger = newpos;
                                return (TRUE);
                        }
                        break;

                case XDR_DECODE:
                        newpos = rstrm->in_finger - delta;
                        if ((delta < (int) (rstrm->fbtbc)) &&
                            (newpos <= rstrm->in_boundry) &&
                            (newpos >= rstrm->in_base)) {
                                rstrm->in_finger = newpos;
                                rstrm->fbtbc -= delta;
                                return (TRUE);
                        }
                        break;
                }
        return (FALSE);
}

static long *
  xdrrec_inline (xdrs, len)
     register XDR *xdrs;
     int len;
{
        register RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
        long *buf = NULL;

        switch (xdrs->x_op) {

        case XDR_ENCODE:
                if ((rstrm->out_finger + len) <= rstrm->out_boundry) {
                        buf = (long *) rstrm->out_finger;
                        rstrm->out_finger += len;
                }
                break;

        case XDR_DECODE:
                if ((len <= rstrm->fbtbc) &&
                    ((rstrm->in_finger + len) <= rstrm->in_boundry)) {
                        buf = (long *) rstrm->in_finger;
                        rstrm->fbtbc -= len;
                        rstrm->in_finger += len;
                }
                break;
        }
        return (buf);
}

static void xdrrec_destroy (xdrs)
     register XDR *xdrs;
{
        register RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;

        mem_free (rstrm->the_buffer,
                  rstrm->sendsize + rstrm->recvsize + BYTES_PER_XDR_UNIT);
        mem_free ((caddr_t) rstrm, sizeof (RECSTREAM));
}


/*
 * Exported routines to manage xdr records
 */

/*
 * Before reading (deserializing from the stream, one should always call
 * this procedure to guarantee proper record alignment.
 */
bool_t
xdrrec_skiprecord (xdrs)
     XDR *xdrs;
{
        register RECSTREAM *rstrm = (RECSTREAM *) (xdrs->x_private);

        while (rstrm->fbtbc > 0 || (!rstrm->last_frag)) {
                if (!skip_input_bytes (rstrm, rstrm->fbtbc))
                        return (FALSE);
                rstrm->fbtbc = 0;
                if ((!rstrm->last_frag) && (!set_input_fragment (rstrm)))
                        return (FALSE);
        }
        rstrm->last_frag = FALSE;
        return (TRUE);
}

/*
 * Look ahead fuction.
 * Returns TRUE iff there is no more input in the buffer 
 * after consuming the rest of the current record.
 */
bool_t
xdrrec_eof (xdrs)
     XDR *xdrs;
{
        register RECSTREAM *rstrm = (RECSTREAM *) (xdrs->x_private);

        while (rstrm->fbtbc > 0 || (!rstrm->last_frag)) {
                if (!skip_input_bytes (rstrm, rstrm->fbtbc))
                        return (TRUE);
                rstrm->fbtbc = 0;
                if ((!rstrm->last_frag) && (!set_input_fragment (rstrm)))
                        return (TRUE);
        }
        if (rstrm->in_finger == rstrm->in_boundry)
                return (TRUE);
        return (FALSE);
}

/*
 * The client must tell the package when an end-of-record has occurred.
 * The second paraemters tells whether the record should be flushed to the
 * (output) tcp stream.  (This let's the package support batched or
 * pipelined procedure calls.)  TRUE => immmediate flush to tcp connection.
 */
bool_t
xdrrec_endofrecord (xdrs, sendnow)
     XDR *xdrs;
     bool_t sendnow;
{
        register RECSTREAM *rstrm = (RECSTREAM *) (xdrs->x_private);
        register u_long len;    /* fragment length */

        if (sendnow || rstrm->frag_sent ||
            ((u_long) rstrm->out_finger + sizeof (u_long) >=
             (u_long) rstrm->out_boundry)) {
                rstrm->frag_sent = FALSE;
                return (flush_out (rstrm, TRUE));
        }
        len = (u_long) (rstrm->out_finger) - (u_long) (rstrm->frag_header) -
                sizeof (u_long);
        *(rstrm->frag_header) = htonl ((u_long) len | LAST_FRAG);
        rstrm->frag_header = (u_long *) rstrm->out_finger;
        rstrm->out_finger += sizeof (u_long);
        return (TRUE);
}


/*
 * Internal useful routines
 */
static bool_t
  flush_out (rstrm, eor)
     register RECSTREAM *rstrm;
     bool_t eor;
{
        register u_long eormask = (eor == TRUE) ? LAST_FRAG : 0;
        register u_long len = (u_long) (rstrm->out_finger) -
        (u_long) (rstrm->frag_header) - sizeof (u_long);

        *(rstrm->frag_header) = htonl (len | eormask);
        len = (u_long) (rstrm->out_finger) - (u_long) (rstrm->out_base);
        if ((*(rstrm->writeit)) (rstrm->tcp_handle, rstrm->out_base, (int) len)
            != (int) len)
                return (FALSE);
        rstrm->frag_header = (u_long *) rstrm->out_base;
        rstrm->out_finger = (caddr_t) rstrm->out_base + sizeof (u_long);
        return (TRUE);
}

static bool_t                   /* knows nothing about records!  Only about input buffers */
  fill_input_buf (rstrm)
     register RECSTREAM *rstrm;
{
        register caddr_t where;
        u_int i;
        register int len;

        where = rstrm->in_base;
        i = (u_int) rstrm->in_boundry % BYTES_PER_XDR_UNIT;
        where += i;
        len = rstrm->in_size - i;
        if ((len = (*(rstrm->readit)) (rstrm->tcp_handle, where, len)) == -1)
                return (FALSE);
        rstrm->in_finger = where;
        where += len;
        rstrm->in_boundry = where;
        return (TRUE);
}

static bool_t                   /* knows nothing about records!  Only about input buffers */
  get_input_bytes (rstrm, addr, len)
     register RECSTREAM *rstrm;
     register caddr_t addr;
     register int len;
{
        register int current;

        while (len > 0) {
                current = (int) rstrm->in_boundry - (int) rstrm->in_finger;
                if (current == 0) {
                        if (!fill_input_buf (rstrm))
                                return (FALSE);
                        continue;
                }
                current = (len < current) ? len : current;
                bcopy (rstrm->in_finger, addr, current);
                rstrm->in_finger += current;
                addr += current;
                len -= current;
        }
        return (TRUE);
}

static bool_t                   /* next two bytes of the input stream are treated as a header */
  set_input_fragment (rstrm)
     register RECSTREAM *rstrm;
{
        u_long header;

        if (!get_input_bytes (rstrm, (caddr_t) & header, sizeof (header)))
                return (FALSE);
        header = (long) ntohl (header);
        rstrm->last_frag = ((header & LAST_FRAG) == 0) ? FALSE : TRUE;
        rstrm->fbtbc = header & (~LAST_FRAG);
        return (TRUE);
}

static bool_t                   /* consumes input bytes; knows nothing about records! */
  skip_input_bytes (rstrm, cnt)
     register RECSTREAM *rstrm;
     long cnt;
{
        register int current;

        while (cnt > 0) {
                current = (int) rstrm->in_boundry - (int) rstrm->in_finger;
                if (current == 0) {
                        if (!fill_input_buf (rstrm))
                                return (FALSE);
                        continue;
                }
                current = (cnt < current) ? cnt : current;
                rstrm->in_finger += current;
                cnt -= current;
        }
        return (TRUE);
}

static u_int
  fix_buf_size (s)
     register u_int s;
{

        if (s < 100)
                s = 4000;
        return (RNDUP (s));
}

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