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 #include <shlib-compat.h>
  42
  43 static bool_t xdrmem_getlong (XDR *, long *);
  44 static bool_t xdrmem_putlong (XDR *, const long *);
  45 static bool_t xdrmem_getbytes (XDR *, caddr_t, u_int);
  46 static bool_t xdrmem_putbytes (XDR *, const char *, u_int);
  47 static u_int xdrmem_getpos (const XDR *);
  48 static bool_t xdrmem_setpos (XDR *, u_int);
  49 static int32_t *xdrmem_inline (XDR *, u_int);
  50 static void xdrmem_destroy (XDR *);
  51 static bool_t xdrmem_getint32 (XDR *, int32_t *);
  52 static bool_t xdrmem_putint32 (XDR *, const int32_t *);
  53
  54 static const struct xdr_ops xdrmem_ops =
  55 {
  56   xdrmem_getlong,
  57   xdrmem_putlong,
  58   xdrmem_getbytes,
  59   xdrmem_putbytes,
  60   xdrmem_getpos,
  61   xdrmem_setpos,
  62   xdrmem_inline,
  63   xdrmem_destroy,
  64   xdrmem_getint32,
  65   xdrmem_putint32
  66 };
  67
  68 /*
  69  * The procedure xdrmem_create initializes a stream descriptor for a
  70  * memory buffer.
  71  */
  72 void
  73 xdrmem_create (XDR *xdrs, const caddr_t addr, u_int size, enum xdr_op op)
  74 {
  75   xdrs->x_op = op;
  76   /* We have to add the const since the `struct xdr_ops' in `struct XDR'
  77      is not `const'.  */
  78   xdrs->x_ops = (struct xdr_ops *) &xdrmem_ops;
  79   xdrs->x_private = xdrs->x_base = addr;
  80   xdrs->x_handy = size;
  81 }
  82 #ifdef EXPORT_RPC_SYMBOLS
  83 libc_hidden_def (xdrmem_create)
  84 #else
  85 libc_hidden_nolink_sunrpc (xdrmem_create, GLIBC_2_0)
  86 #endif
  87
  88 /*
  89  * Nothing needs to be done for the memory case.  The argument is clearly
  90  * const.
  91  */
  92
  93 static void
  94 xdrmem_destroy (XDR *xdrs)
  95 {
  96 }
  97
  98 /*
  99  * Gets the next word from the memory referenced by xdrs and places it
 100  * in the long pointed to by lp.  It then increments the private word to
 101  * point at the next element.  Neither object pointed to is const
 102  */
 103 static bool_t
 104 xdrmem_getlong (XDR *xdrs, long *lp)
 105 {
 106   if (xdrs->x_handy < 4)
 107     return FALSE;
 108   xdrs->x_handy -= 4;
 109   *lp = (int32_t) ntohl ((*((int32_t *) (xdrs->x_private))));
 110   xdrs->x_private += 4;
 111   return TRUE;
 112 }
 113
 114 /*
 115  * Puts the long pointed to by lp in the memory referenced by xdrs.  It
 116  * then increments the private word to point at the next element.  The
 117  * long pointed at is const
 118  */
 119 static bool_t
 120 xdrmem_putlong (XDR *xdrs, const long *lp)
 121 {
 122   if (xdrs->x_handy < 4)
 123     return FALSE;
 124   xdrs->x_handy -= 4;
 125   *(int32_t *) xdrs->x_private = htonl (*lp);
 126   xdrs->x_private += 4;
 127   return TRUE;
 128 }
 129
 130 /*
 131  * Gets an unaligned number of bytes from the xdrs structure and writes them
 132  * to the address passed in addr.  Be very careful when calling this routine
 133  * as it could leave the xdrs pointing to an unaligned structure which is not
 134  * a good idea.  None of the things pointed to are const.
 135  */
 136 static bool_t
 137 xdrmem_getbytes (XDR *xdrs, caddr_t addr, u_int len)
 138 {
 139   if (xdrs->x_handy < len)
 140     return FALSE;
 141   xdrs->x_handy -= len;
 142   memcpy (addr, xdrs->x_private, len);
 143   xdrs->x_private += len;
 144   return TRUE;
 145 }
 146
 147 /*
 148  * The complementary function to the above.  The same warnings apply about
 149  * unaligned data.  The source address is const.
 150  */
 151 static bool_t
 152 xdrmem_putbytes (XDR *xdrs, const char *addr, u_int len)
 153 {
 154   if (xdrs->x_handy < len)
 155     return FALSE;
 156   xdrs->x_handy -= len;
 157   memcpy (xdrs->x_private, addr, len);
 158   xdrs->x_private += len;
 159   return TRUE;
 160 }
 161
 162 /*
 163  * Not sure what this one does.  But it clearly doesn't modify the contents
 164  * of xdrs.  **FIXME** does this not assume u_int == u_long?
 165  */
 166 static u_int
 167 xdrmem_getpos (const XDR *xdrs)
 168 {
 169   return (u_long) xdrs->x_private - (u_long) xdrs->x_base;
 170 }
 171
 172 /*
 173  * xdrs modified
 174  */
 175 static bool_t
 176 xdrmem_setpos (XDR *xdrs, u_int pos)
 177 {
 178   caddr_t newaddr = xdrs->x_base + pos;
 179   caddr_t lastaddr = xdrs->x_private + xdrs->x_handy;
 180   size_t handy = lastaddr - newaddr;
 181
 182   if (newaddr > lastaddr
 183       || newaddr < xdrs->x_base
 184       || handy != (u_int) handy)
 185     return FALSE;
 186
 187   xdrs->x_private = newaddr;
 188   xdrs->x_handy = (u_int) handy;
 189   return TRUE;
 190 }
 191
 192 /*
 193  * xdrs modified
 194  */
 195 static int32_t *
 196 xdrmem_inline (XDR *xdrs, u_int len)
 197 {
 198   int32_t *buf = 0;
 199
 200   if (xdrs->x_handy >= len)
 201     {
 202       xdrs->x_handy -= len;
 203       buf = (int32_t *) xdrs->x_private;
 204       xdrs->x_private += len;
 205     }
 206   return buf;
 207 }
 208
 209 /*
 210  * Gets the next word from the memory referenced by xdrs and places it
 211  * in the int pointed to by ip.  It then increments the private word to
 212  * point at the next element.  Neither object pointed to is const
 213  */
 214 static bool_t
 215 xdrmem_getint32 (XDR *xdrs, int32_t *ip)
 216 {
 217   if (xdrs->x_handy < 4)
 218     return FALSE;
 219   xdrs->x_handy -= 4;
 220   *ip = ntohl ((*((int32_t *) (xdrs->x_private))));
 221   xdrs->x_private += 4;
 222   return TRUE;
 223 }
 224
 225 /*
 226  * Puts the long pointed to by lp in the memory referenced by xdrs.  It
 227  * then increments the private word to point at the next element.  The
 228  * long pointed at is const
 229  */
 230 static bool_t
 231 xdrmem_putint32 (XDR *xdrs, const int32_t *ip)
 232 {
 233   if (xdrs->x_handy < 4)
 234     return FALSE;
 235   xdrs->x_handy -= 4;
 236   *(int32_t *) xdrs->x_private = htonl (*ip);
 237   xdrs->x_private += 4;
 238   return TRUE;
 239 }