sunrpc/xdr_mem.c

   1 /*
   2  * xdr_mem.c, XDR implementation using memory buffers.
   3  *
   4  * Copyright (c) 2010, Oracle America, Inc.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions are
   8  * met:
   9  *
  10  *     * Redistributions of source code must retain the above copyright
  11  *       notice, this list of conditions and the following disclaimer.
  12  *     * Redistributions in binary form must reproduce the above
  13  *       copyright notice, this list of conditions and the following
  14  *       disclaimer in the documentation and/or other materials
  15  *       provided with the distribution.
  16  *     * Neither the name of the "Oracle America, Inc." nor the names of its
  17  *       contributors may be used to endorse or promote products derived
  18  *       from this software without specific prior written permission.
  19  *
  20  *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  21  *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  22  *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  23  *   FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
  24  *   COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
  25  *   INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  *   DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
  27  *   GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  28  *   INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
  29  *   WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  30  *   NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  31  *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  32  *
  33  * If you have some data to be interpreted as external data representation
  34  * or to be converted to external data representation in a memory buffer,
  35  * then this is the package for you.
  36  */
  37
  38 #include <string.h>
  39 #include <limits.h>
  40 #include <rpc/rpc.h>
  41
  42 static bool_t xdrmem_getlong (XDR *, long *);
  43 static bool_t xdrmem_putlong (XDR *, const long *);
  44 static bool_t xdrmem_getbytes (XDR *, caddr_t, u_int);
  45 static bool_t xdrmem_putbytes (XDR *, const char *, u_int);
  46 static u_int xdrmem_getpos (const XDR *);
  47 static bool_t xdrmem_setpos (XDR *, u_int);
  48 static int32_t *xdrmem_inline (XDR *, u_int);
  49 static void xdrmem_destroy (XDR *);
  50 static bool_t xdrmem_getint32 (XDR *, int32_t *);
  51 static bool_t xdrmem_putint32 (XDR *, const int32_t *);
  52
  53 static const struct xdr_ops xdrmem_ops =
  54 {
  55   xdrmem_getlong,
  56   xdrmem_putlong,
  57   xdrmem_getbytes,
  58   xdrmem_putbytes,
  59   xdrmem_getpos,
  60   xdrmem_setpos,
  61   xdrmem_inline,
  62   xdrmem_destroy,
  63   xdrmem_getint32,
  64   xdrmem_putint32
  65 };
  66
  67 /*
  68  * The procedure xdrmem_create initializes a stream descriptor for a
  69  * memory buffer.
  70  */
  71 void
  72 xdrmem_create (XDR *xdrs, const caddr_t addr, u_int size, enum xdr_op op)
  73 {
  74   xdrs->x_op = op;
  75   /* We have to add the const since the `struct xdr_ops' in `struct XDR'
  76      is not `const'.  */
  77   xdrs->x_ops = (struct xdr_ops *) &xdrmem_ops;
  78   xdrs->x_private = xdrs->x_base = addr;
  79   xdrs->x_handy = size;
  80 }
  81 INTDEF(xdrmem_create)
  82
  83 /*
  84  * Nothing needs to be done for the memory case.  The argument is clearly
  85  * const.
  86  */
  87
  88 static void
  89 xdrmem_destroy (XDR *xdrs)
  90 {
  91 }
  92
  93 /*
  94  * Gets the next word from the memory referenced by xdrs and places it
  95  * in the long pointed to by lp.  It then increments the private word to
  96  * point at the next element.  Neither object pointed to is const
  97  */
  98 static bool_t
  99 xdrmem_getlong (XDR *xdrs, long *lp)
 100 {
 101   if (xdrs->x_handy < 4)
 102     return FALSE;
 103   xdrs->x_handy -= 4;
 104   *lp = (int32_t) ntohl ((*((int32_t *) (xdrs->x_private))));
 105   xdrs->x_private += 4;
 106   return TRUE;
 107 }
 108
 109 /*
 110  * Puts the long pointed to by lp in the memory referenced by xdrs.  It
 111  * then increments the private word to point at the next element.  The
 112  * long pointed at is const
 113  */
 114 static bool_t
 115 xdrmem_putlong (XDR *xdrs, const long *lp)
 116 {
 117   if (xdrs->x_handy < 4)
 118     return FALSE;
 119   xdrs->x_handy -= 4;
 120   *(int32_t *) xdrs->x_private = htonl (*lp);
 121   xdrs->x_private += 4;
 122   return TRUE;
 123 }
 124
 125 /*
 126  * Gets an unaligned number of bytes from the xdrs structure and writes them
 127  * to the address passed in addr.  Be very careful when calling this routine
 128  * as it could leave the xdrs pointing to an unaligned structure which is not
 129  * a good idea.  None of the things pointed to are const.
 130  */
 131 static bool_t
 132 xdrmem_getbytes (XDR *xdrs, caddr_t addr, u_int len)
 133 {
 134   if (xdrs->x_handy < len)
 135     return FALSE;
 136   xdrs->x_handy -= len;
 137   memcpy (addr, xdrs->x_private, len);
 138   xdrs->x_private += len;
 139   return TRUE;
 140 }
 141
 142 /*
 143  * The complementary function to the above.  The same warnings apply about
 144  * unaligned data.  The source address is const.
 145  */
 146 static bool_t
 147 xdrmem_putbytes (XDR *xdrs, const char *addr, u_int len)
 148 {
 149   if (xdrs->x_handy < len)
 150     return FALSE;
 151   xdrs->x_handy -= len;
 152   memcpy (xdrs->x_private, addr, len);
 153   xdrs->x_private += len;
 154   return TRUE;
 155 }
 156
 157 /*
 158  * Not sure what this one does.  But it clearly doesn't modify the contents
 159  * of xdrs.  **FIXME** does this not assume u_int == u_long?
 160  */
 161 static u_int
 162 xdrmem_getpos (const XDR *xdrs)
 163 {
 164   return (u_long) xdrs->x_private - (u_long) xdrs->x_base;
 165 }
 166
 167 /*
 168  * xdrs modified
 169  */
 170 static bool_t
 171 xdrmem_setpos (xdrs, pos)
 172      XDR *xdrs;
 173      u_int pos;
 174 {
 175   caddr_t newaddr = xdrs->x_base + pos;
 176   caddr_t lastaddr = xdrs->x_private + xdrs->x_handy;
 177   size_t handy = lastaddr - newaddr;
 178
 179   if (newaddr > lastaddr
 180       || newaddr < xdrs->x_base
 181       || handy != (u_int) handy)
 182     return FALSE;
 183
 184   xdrs->x_private = newaddr;
 185   xdrs->x_handy = (u_int) handy;
 186   return TRUE;
 187 }
 188
 189 /*
 190  * xdrs modified
 191  */
 192 static int32_t *
 193 xdrmem_inline (XDR *xdrs, u_int len)
 194 {
 195   int32_t *buf = 0;
 196
 197   if (xdrs->x_handy >= len)
 198     {
 199       xdrs->x_handy -= len;
 200       buf = (int32_t *) xdrs->x_private;
 201       xdrs->x_private += len;
 202     }
 203   return buf;
 204 }
 205
 206 /*
 207  * Gets the next word from the memory referenced by xdrs and places it
 208  * in the int pointed to by ip.  It then increments the private word to
 209  * point at the next element.  Neither object pointed to is const
 210  */
 211 static bool_t
 212 xdrmem_getint32 (XDR *xdrs, int32_t *ip)
 213 {
 214   if (xdrs->x_handy < 4)
 215     return FALSE;
 216   xdrs->x_handy -= 4;
 217   *ip = ntohl ((*((int32_t *) (xdrs->x_private))));
 218   xdrs->x_private += 4;
 219   return TRUE;
 220 }
 221
 222 /*
 223  * Puts the long pointed to by lp in the memory referenced by xdrs.  It
 224  * then increments the private word to point at the next element.  The
 225  * long pointed at is const
 226  */
 227 static bool_t
 228 xdrmem_putint32 (XDR *xdrs, const int32_t *ip)
 229 {
 230   if (xdrs->x_handy < 4)
 231     return FALSE;
 232   xdrs->x_handy -= 4;
 233   *(int32_t *) xdrs->x_private = htonl (*ip);
 234   xdrs->x_private += 4;
 235   return TRUE;
 236 }