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 #ifdef EXPORT_RPC_SYMBOLS
  82 libc_hidden_def (xdrmem_create)
  83 #else
  84 libc_hidden_nolink_sunrpc (xdrmem_create, GLIBC_2_0)
  85 #endif
  86
  87 /*
  88  * Nothing needs to be done for the memory case.  The argument is clearly
  89  * const.
  90  */
  91
  92 static void
  93 xdrmem_destroy (XDR *xdrs)
  94 {
  95 }
  96
  97 /*
  98  * Gets the next word from the memory referenced by xdrs and places it
  99  * in the long pointed to by lp.  It then increments the private word to
 100  * point at the next element.  Neither object pointed to is const
 101  */
 102 static bool_t
 103 xdrmem_getlong (XDR *xdrs, long *lp)
 104 {
 105   if (xdrs->x_handy < 4)
 106     return FALSE;
 107   xdrs->x_handy -= 4;
 108   *lp = (int32_t) ntohl ((*((int32_t *) (xdrs->x_private))));
 109   xdrs->x_private += 4;
 110   return TRUE;
 111 }
 112
 113 /*
 114  * Puts the long pointed to by lp in the memory referenced by xdrs.  It
 115  * then increments the private word to point at the next element.  The
 116  * long pointed at is const
 117  */
 118 static bool_t
 119 xdrmem_putlong (XDR *xdrs, const long *lp)
 120 {
 121   if (xdrs->x_handy < 4)
 122     return FALSE;
 123   xdrs->x_handy -= 4;
 124   *(int32_t *) xdrs->x_private = htonl (*lp);
 125   xdrs->x_private += 4;
 126   return TRUE;
 127 }
 128
 129 /*
 130  * Gets an unaligned number of bytes from the xdrs structure and writes them
 131  * to the address passed in addr.  Be very careful when calling this routine
 132  * as it could leave the xdrs pointing to an unaligned structure which is not
 133  * a good idea.  None of the things pointed to are const.
 134  */
 135 static bool_t
 136 xdrmem_getbytes (XDR *xdrs, caddr_t addr, u_int len)
 137 {
 138   if (xdrs->x_handy < len)
 139     return FALSE;
 140   xdrs->x_handy -= len;
 141   memcpy (addr, xdrs->x_private, len);
 142   xdrs->x_private += len;
 143   return TRUE;
 144 }
 145
 146 /*
 147  * The complementary function to the above.  The same warnings apply about
 148  * unaligned data.  The source address is const.
 149  */
 150 static bool_t
 151 xdrmem_putbytes (XDR *xdrs, const char *addr, u_int len)
 152 {
 153   if (xdrs->x_handy < len)
 154     return FALSE;
 155   xdrs->x_handy -= len;
 156   memcpy (xdrs->x_private, addr, len);
 157   xdrs->x_private += len;
 158   return TRUE;
 159 }
 160
 161 /*
 162  * Not sure what this one does.  But it clearly doesn't modify the contents
 163  * of xdrs.  **FIXME** does this not assume u_int == u_long?
 164  */
 165 static u_int
 166 xdrmem_getpos (const XDR *xdrs)
 167 {
 168   return (u_long) xdrs->x_private - (u_long) xdrs->x_base;
 169 }
 170
 171 /*
 172  * xdrs modified
 173  */
 174 static bool_t
 175 xdrmem_setpos (xdrs, pos)
 176      XDR *xdrs;
 177      u_int pos;
 178 {
 179   caddr_t newaddr = xdrs->x_base + pos;
 180   caddr_t lastaddr = xdrs->x_private + xdrs->x_handy;
 181   size_t handy = lastaddr - newaddr;
 182
 183   if (newaddr > lastaddr
 184       || newaddr < xdrs->x_base
 185       || handy != (u_int) handy)
 186     return FALSE;
 187
 188   xdrs->x_private = newaddr;
 189   xdrs->x_handy = (u_int) handy;
 190   return TRUE;
 191 }
 192
 193 /*
 194  * xdrs modified
 195  */
 196 static int32_t *
 197 xdrmem_inline (XDR *xdrs, u_int len)
 198 {
 199   int32_t *buf = 0;
 200
 201   if (xdrs->x_handy >= len)
 202     {
 203       xdrs->x_handy -= len;
 204       buf = (int32_t *) xdrs->x_private;
 205       xdrs->x_private += len;
 206     }
 207   return buf;
 208 }
 209
 210 /*
 211  * Gets the next word from the memory referenced by xdrs and places it
 212  * in the int pointed to by ip.  It then increments the private word to
 213  * point at the next element.  Neither object pointed to is const
 214  */
 215 static bool_t
 216 xdrmem_getint32 (XDR *xdrs, int32_t *ip)
 217 {
 218   if (xdrs->x_handy < 4)
 219     return FALSE;
 220   xdrs->x_handy -= 4;
 221   *ip = ntohl ((*((int32_t *) (xdrs->x_private))));
 222   xdrs->x_private += 4;
 223   return TRUE;
 224 }
 225
 226 /*
 227  * Puts the long pointed to by lp in the memory referenced by xdrs.  It
 228  * then increments the private word to point at the next element.  The
 229  * long pointed at is const
 230  */
 231 static bool_t
 232 xdrmem_putint32 (XDR *xdrs, const int32_t *ip)
 233 {
 234   if (xdrs->x_handy < 4)
 235     return FALSE;
 236   xdrs->x_handy -= 4;
 237   *(int32_t *) xdrs->x_private = htonl (*ip);
 238   xdrs->x_private += 4;
 239   return TRUE;
 240 }