sunrpc/xdr_rec.c

   1 /* @(#)xdr_rec.c        2.2 88/08/01 4.0 RPCSRC */
   2 /*
   3  * Sun RPC is a product of Sun Microsystems, Inc. and is provided for
   4  * unrestricted use provided that this legend is included on all tape
   5  * media and as a part of the software program in whole or part.  Users
   6  * may copy or modify Sun RPC without charge, but are not authorized
   7  * to license or distribute it to anyone else except as part of a product or
   8  * program developed by the user.
   9  *
  10  * SUN RPC IS PROVIDED AS IS WITH NO WARRANTIES OF ANY KIND INCLUDING THE
  11  * WARRANTIES OF DESIGN, MERCHANTIBILITY AND FITNESS FOR A PARTICULAR
  12  * PURPOSE, OR ARISING FROM A COURSE OF DEALING, USAGE OR TRADE PRACTICE.
  13  *
  14  * Sun RPC is provided with no support and without any obligation on the
  15  * part of Sun Microsystems, Inc. to assist in its use, correction,
  16  * modification or enhancement.
  17  *
  18  * SUN MICROSYSTEMS, INC. SHALL HAVE NO LIABILITY WITH RESPECT TO THE
  19  * INFRINGEMENT OF COPYRIGHTS, TRADE SECRETS OR ANY PATENTS BY SUN RPC
  20  * OR ANY PART THEREOF.
  21  *
  22  * In no event will Sun Microsystems, Inc. be liable for any lost revenue
  23  * or profits or other special, indirect and consequential damages, even if
  24  * Sun has been advised of the possibility of such damages.
  25  *
  26  * Sun Microsystems, Inc.
  27  * 2550 Garcia Avenue
  28  * Mountain View, California  94043
  29  */
  30 #if !defined(lint) && defined(SCCSIDS)
  31 static char sccsid[] = "@(#)xdr_rec.c 1.21 87/08/11 Copyr 1984 Sun Micro";
  32 #endif
  33
  34 /*
  35  * xdr_rec.c, Implements TCP/IP based XDR streams with a "record marking"
  36  * layer above tcp (for rpc's use).
  37  *
  38  * Copyright (C) 1984, Sun Microsystems, Inc.
  39  *
  40  * These routines interface XDRSTREAMS to a tcp/ip connection.
  41  * There is a record marking layer between the xdr stream
  42  * and the tcp transport level.  A record is composed on one or more
  43  * record fragments.  A record fragment is a thirty-two bit header followed
  44  * by n bytes of data, where n is contained in the header.  The header
  45  * is represented as a htonl(u_long).  The high order bit encodes
  46  * whether or not the fragment is the last fragment of the record
  47  * (1 => fragment is last, 0 => more fragments to follow.
  48  * The other 31 bits encode the byte length of the fragment.
  49  */
  50
  51 #include <stdio.h>
  52 #include <string.h>
  53 #include <unistd.h>
  54 #include <rpc/rpc.h>
  55
  56 static bool_t xdrrec_getlong (XDR *, long *);
  57 static bool_t xdrrec_putlong (XDR *, const long *);
  58 static bool_t xdrrec_getbytes (XDR *, caddr_t, u_int);
  59 static bool_t xdrrec_putbytes (XDR *, const char *, u_int);
  60 static u_int xdrrec_getpos (const XDR *);
  61 static bool_t xdrrec_setpos (XDR *, u_int);
  62 static long *xdrrec_inline (XDR *, int);
  63 static void xdrrec_destroy (XDR *);
  64
  65 static const struct xdr_ops xdrrec_ops =
  66 {
  67   xdrrec_getlong,
  68   xdrrec_putlong,
  69   xdrrec_getbytes,
  70   xdrrec_putbytes,
  71   xdrrec_getpos,
  72   xdrrec_setpos,
  73   xdrrec_inline,
  74   xdrrec_destroy
  75 };
  76
  77 /*
  78  * A record is composed of one or more record fragments.
  79  * A record fragment is a two-byte header followed by zero to
  80  * 2**32-1 bytes.  The header is treated as a long unsigned and is
  81  * encode/decoded to the network via htonl/ntohl.  The low order 31 bits
  82  * are a byte count of the fragment.  The highest order bit is a boolean:
  83  * 1 => this fragment is the last fragment of the record,
  84  * 0 => this fragment is followed by more fragment(s).
  85  *
  86  * The fragment/record machinery is not general;  it is constructed to
  87  * meet the needs of xdr and rpc based on tcp.
  88  */
  89
  90 #define LAST_FRAG (1UL << 31)
  91
  92 typedef struct rec_strm
  93   {
  94     caddr_t tcp_handle;
  95     caddr_t the_buffer;
  96     /*
  97      * out-going bits
  98      */
  99     int (*writeit) (char *, char *, int);
 100     caddr_t out_base;           /* output buffer (points to frag header) */
 101     caddr_t out_finger;         /* next output position */
 102     caddr_t out_boundry;        /* data cannot up to this address */
 103     u_int32_t *frag_header;     /* beginning of curren fragment */
 104     bool_t frag_sent;           /* true if buffer sent in middle of record */
 105     /*
 106      * in-coming bits
 107      */
 108     int (*readit) (char *, char *, int);
 109     u_long in_size;             /* fixed size of the input buffer */
 110     caddr_t in_base;
 111     caddr_t in_finger;          /* location of next byte to be had */
 112     caddr_t in_boundry;         /* can read up to this location */
 113     long fbtbc;                 /* fragment bytes to be consumed */
 114     bool_t last_frag;
 115     u_int sendsize;
 116     u_int recvsize;
 117   }
 118 RECSTREAM;
 119
 120 static u_int fix_buf_size (u_int) internal_function;
 121 static bool_t skip_input_bytes (RECSTREAM *, long) internal_function;
 122 static bool_t flush_out (RECSTREAM *, bool_t) internal_function;
 123 static bool_t set_input_fragment (RECSTREAM *) internal_function;
 124 static bool_t get_input_bytes (RECSTREAM *, caddr_t, int) internal_function;
 125
 126 /*
 127  * Create an xdr handle for xdrrec
 128  * xdrrec_create fills in xdrs.  Sendsize and recvsize are
 129  * send and recv buffer sizes (0 => use default).
 130  * tcp_handle is an opaque handle that is passed as the first parameter to
 131  * the procedures readit and writeit.  Readit and writeit are read and
 132  * write respectively.   They are like the system
 133  * calls expect that they take an opaque handle rather than an fd.
 134  */
 135 void
 136 xdrrec_create (XDR *xdrs, u_int sendsize,
 137                u_int recvsize, caddr_t tcp_handle,
 138                int (*readit) (char *, char *, int),
 139                int (*writeit) (char *, char *, int))
 140 {
 141   RECSTREAM *rstrm = (RECSTREAM *) mem_alloc (sizeof (RECSTREAM));
 142   caddr_t tmp;
 143
 144   if (rstrm == NULL)
 145     {
 146       (void) fputs (_("xdrrec_create: out of memory\n"), stderr);
 147       /*
 148        *  This is bad.  Should rework xdrrec_create to
 149        *  return a handle, and in this case return NULL
 150        */
 151       return;
 152     }
 153   /*
 154    * adjust sizes and allocate buffer quad byte aligned
 155    */
 156   rstrm->sendsize = sendsize = fix_buf_size (sendsize);
 157   rstrm->recvsize = recvsize = fix_buf_size (recvsize);
 158   rstrm->the_buffer = mem_alloc (sendsize + recvsize + BYTES_PER_XDR_UNIT);
 159   if (rstrm->the_buffer == NULL)
 160     {
 161       (void) fputs (_("xdrrec_create: out of memory\n"), stderr);
 162       return;
 163     }
 164   tmp = rstrm->the_buffer;
 165   if ((size_t)tmp % BYTES_PER_XDR_UNIT)
 166     tmp += BYTES_PER_XDR_UNIT - (size_t)tmp % BYTES_PER_XDR_UNIT;
 167   rstrm->out_base = tmp;
 168   rstrm->in_base = tmp + sendsize;
 169   /*
 170    * now the rest ...
 171    */
 172   xdrs->x_ops = &xdrrec_ops;
 173   xdrs->x_private = (caddr_t) rstrm;
 174   rstrm->tcp_handle = tcp_handle;
 175   rstrm->readit = readit;
 176   rstrm->writeit = writeit;
 177   rstrm->out_finger = rstrm->out_boundry = rstrm->out_base;
 178   rstrm->frag_header = (u_int32_t *) rstrm->out_base;
 179   rstrm->out_finger += 4;
 180   rstrm->out_boundry += sendsize;
 181   rstrm->frag_sent = FALSE;
 182   rstrm->in_size = recvsize;
 183   rstrm->in_boundry = rstrm->in_base;
 184   rstrm->in_finger = (rstrm->in_boundry += recvsize);
 185   rstrm->fbtbc = 0;
 186   rstrm->last_frag = TRUE;
 187 }
 188
 189
 190 /*
 191  * The routines defined below are the xdr ops which will go into the
 192  * xdr handle filled in by xdrrec_create.
 193  */
 194
 195 static bool_t
 196 xdrrec_getlong (xdrs, lp)
 197      XDR *xdrs;
 198      long *lp;
 199 {
 200   RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
 201   int32_t *buflp = (int32_t *) rstrm->in_finger;
 202   int32_t mylong;
 203
 204   /* first try the inline, fast case */
 205   if (rstrm->fbtbc >= BYTES_PER_XDR_UNIT &&
 206       rstrm->in_boundry - (char *) buflp >= BYTES_PER_XDR_UNIT)
 207     {
 208       *lp = (int32_t) ntohl (*buflp);
 209       rstrm->fbtbc -= BYTES_PER_XDR_UNIT;
 210       rstrm->in_finger += BYTES_PER_XDR_UNIT;
 211     }
 212   else
 213     {
 214       if (!xdrrec_getbytes (xdrs, (caddr_t) & mylong,
 215                             BYTES_PER_XDR_UNIT))
 216         return FALSE;
 217       *lp = (int32_t) ntohl (mylong);
 218     }
 219   return TRUE;
 220 }
 221
 222 static bool_t
 223 xdrrec_putlong (xdrs, lp)
 224      XDR *xdrs;
 225      const long *lp;
 226 {
 227   RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
 228   int32_t *dest_lp = (int32_t *) rstrm->out_finger;
 229
 230   if ((rstrm->out_finger += BYTES_PER_XDR_UNIT) > rstrm->out_boundry)
 231     {
 232       /*
 233        * this case should almost never happen so the code is
 234        * inefficient
 235        */
 236       rstrm->out_finger -= BYTES_PER_XDR_UNIT;
 237       rstrm->frag_sent = TRUE;
 238       if (!flush_out (rstrm, FALSE))
 239         return FALSE;
 240       dest_lp = (int32_t *) rstrm->out_finger;
 241       rstrm->out_finger += BYTES_PER_XDR_UNIT;
 242     }
 243   *dest_lp = htonl (*lp);
 244   return TRUE;
 245 }
 246
 247 static bool_t                   /* must manage buffers, fragments, and records */
 248 xdrrec_getbytes (xdrs, addr, len)
 249      XDR *xdrs;
 250      caddr_t addr;
 251      u_int len;
 252 {
 253   RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
 254   u_int current;
 255
 256   while (len > 0)
 257     {
 258       current = rstrm->fbtbc;
 259       if (current == 0)
 260         {
 261           if (rstrm->last_frag)
 262             return FALSE;
 263           if (!set_input_fragment (rstrm))
 264             return FALSE;
 265           continue;
 266         }
 267       current = (len < current) ? len : current;
 268       if (!get_input_bytes (rstrm, addr, current))
 269         return FALSE;
 270       addr += current;
 271       rstrm->fbtbc -= current;
 272       len -= current;
 273     }
 274   return TRUE;
 275 }
 276
 277 static bool_t
 278 xdrrec_putbytes (xdrs, addr, len)
 279      XDR *xdrs;
 280      const char *addr;
 281      u_int len;
 282 {
 283   RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
 284   u_int current;
 285
 286   while (len > 0)
 287     {
 288       current = rstrm->out_boundry - rstrm->out_finger;
 289       current = (len < current) ? len : current;
 290       bcopy (addr, rstrm->out_finger, current);
 291       rstrm->out_finger += current;
 292       addr += current;
 293       len -= current;
 294       if (rstrm->out_finger == rstrm->out_boundry)
 295         {
 296           rstrm->frag_sent = TRUE;
 297           if (!flush_out (rstrm, FALSE))
 298             return FALSE;
 299         }
 300     }
 301   return TRUE;
 302 }
 303
 304 static u_int
 305 xdrrec_getpos (const XDR *xdrs)
 306 {
 307   RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
 308   long pos;
 309
 310   pos = lseek ((int) rstrm->tcp_handle, (long) 0, 1);
 311   if (pos != -1)
 312     switch (xdrs->x_op)
 313       {
 314
 315       case XDR_ENCODE:
 316         pos += rstrm->out_finger - rstrm->out_base;
 317         break;
 318
 319       case XDR_DECODE:
 320         pos -= rstrm->in_boundry - rstrm->in_finger;
 321         break;
 322
 323       default:
 324         pos = (u_int) - 1;
 325         break;
 326       }
 327   return (u_int) pos;
 328 }
 329
 330 static bool_t
 331 xdrrec_setpos (xdrs, pos)
 332      XDR *xdrs;
 333      u_int pos;
 334 {
 335   RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
 336   u_int currpos = xdrrec_getpos (xdrs);
 337   int delta = currpos - pos;
 338   caddr_t newpos;
 339
 340   if ((int) currpos != -1)
 341     switch (xdrs->x_op)
 342       {
 343
 344       case XDR_ENCODE:
 345         newpos = rstrm->out_finger - delta;
 346         if (newpos > (caddr_t) rstrm->frag_header &&
 347             newpos < rstrm->out_boundry)
 348           {
 349             rstrm->out_finger = newpos;
 350             return TRUE;
 351           }
 352         break;
 353
 354       case XDR_DECODE:
 355         newpos = rstrm->in_finger - delta;
 356         if ((delta < (int) (rstrm->fbtbc)) &&
 357             (newpos <= rstrm->in_boundry) &&
 358             (newpos >= rstrm->in_base))
 359           {
 360             rstrm->in_finger = newpos;
 361             rstrm->fbtbc -= delta;
 362             return TRUE;
 363           }
 364         break;
 365
 366       default:
 367         break;
 368       }
 369   return FALSE;
 370 }
 371
 372 static long *
 373 xdrrec_inline (XDR *xdrs, int len)
 374 {
 375   RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
 376   long *buf = NULL;
 377
 378   switch (xdrs->x_op)
 379     {
 380
 381     case XDR_ENCODE:
 382       if ((rstrm->out_finger + len) <= rstrm->out_boundry)
 383         {
 384           buf = (long *) rstrm->out_finger;
 385           rstrm->out_finger += len;
 386         }
 387       break;
 388
 389     case XDR_DECODE:
 390       if ((len <= rstrm->fbtbc) &&
 391           ((rstrm->in_finger + len) <= rstrm->in_boundry))
 392         {
 393           buf = (long *) rstrm->in_finger;
 394           rstrm->fbtbc -= len;
 395           rstrm->in_finger += len;
 396         }
 397       break;
 398
 399     default:
 400       break;
 401     }
 402   return buf;
 403 }
 404
 405 static void
 406 xdrrec_destroy (xdrs)
 407      XDR *xdrs;
 408 {
 409   RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
 410
 411   mem_free (rstrm->the_buffer,
 412             rstrm->sendsize + rstrm->recvsize + BYTES_PER_XDR_UNIT);
 413   mem_free ((caddr_t) rstrm, sizeof (RECSTREAM));
 414 }
 415
 416
 417 /*
 418  * Exported routines to manage xdr records
 419  */
 420
 421 /*
 422  * Before reading (deserializing from the stream, one should always call
 423  * this procedure to guarantee proper record alignment.
 424  */
 425 bool_t
 426 xdrrec_skiprecord (xdrs)
 427      XDR *xdrs;
 428 {
 429   RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
 430
 431   while (rstrm->fbtbc > 0 || (!rstrm->last_frag))
 432     {
 433       if (!skip_input_bytes (rstrm, rstrm->fbtbc))
 434         return FALSE;
 435       rstrm->fbtbc = 0;
 436       if ((!rstrm->last_frag) && (!set_input_fragment (rstrm)))
 437         return FALSE;
 438     }
 439   rstrm->last_frag = FALSE;
 440   return TRUE;
 441 }
 442
 443 /*
 444  * Lookahead function.
 445  * Returns TRUE iff there is no more input in the buffer
 446  * after consuming the rest of the current record.
 447  */
 448 bool_t
 449 xdrrec_eof (xdrs)
 450      XDR *xdrs;
 451 {
 452   RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
 453
 454   while (rstrm->fbtbc > 0 || (!rstrm->last_frag))
 455     {
 456       if (!skip_input_bytes (rstrm, rstrm->fbtbc))
 457         return TRUE;
 458       rstrm->fbtbc = 0;
 459       if ((!rstrm->last_frag) && (!set_input_fragment (rstrm)))
 460         return TRUE;
 461     }
 462   if (rstrm->in_finger == rstrm->in_boundry)
 463     return TRUE;
 464   return FALSE;
 465 }
 466
 467 /*
 468  * The client must tell the package when an end-of-record has occurred.
 469  * The second parameter tells whether the record should be flushed to the
 470  * (output) tcp stream.  (This lets the package support batched or
 471  * pipelined procedure calls.)  TRUE => immediate flush to tcp connection.
 472  */
 473 bool_t
 474 xdrrec_endofrecord (xdrs, sendnow)
 475      XDR *xdrs;
 476      bool_t sendnow;
 477 {
 478   RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
 479   u_long len;           /* fragment length */
 480
 481   if (sendnow || rstrm->frag_sent
 482       || rstrm->out_finger + BYTES_PER_XDR_UNIT >= rstrm->out_boundry)
 483     {
 484       rstrm->frag_sent = FALSE;
 485       return flush_out (rstrm, TRUE);
 486     }
 487   len = (rstrm->out_finger - (char *) rstrm->frag_header
 488          - BYTES_PER_XDR_UNIT);
 489   *rstrm->frag_header = htonl ((u_long) len | LAST_FRAG);
 490   rstrm->frag_header = (u_int32_t *) rstrm->out_finger;
 491   rstrm->out_finger += BYTES_PER_XDR_UNIT;
 492   return TRUE;
 493 }
 494
 495
 496 /*
 497  * Internal useful routines
 498  */
 499 static bool_t
 500 internal_function
 501 flush_out (RECSTREAM *rstrm, bool_t eor)
 502 {
 503   u_long eormask = (eor == TRUE) ? LAST_FRAG : 0;
 504   u_long len = (rstrm->out_finger - (char *) rstrm->frag_header
 505                 - BYTES_PER_XDR_UNIT);
 506
 507   *rstrm->frag_header = htonl (len | eormask);
 508   len = rstrm->out_finger - rstrm->out_base;
 509   if ((*(rstrm->writeit)) (rstrm->tcp_handle, rstrm->out_base, (int) len)
 510       != (int) len)
 511     return FALSE;
 512   rstrm->frag_header = (u_int32_t *) rstrm->out_base;
 513   rstrm->out_finger = (caddr_t) rstrm->out_base + BYTES_PER_XDR_UNIT;
 514   return TRUE;
 515 }
 516
 517 static bool_t   /* knows nothing about records!  Only about input buffers */
 518 fill_input_buf (RECSTREAM *rstrm)
 519 {
 520   caddr_t where;
 521   size_t i;
 522   int len;
 523
 524   where = rstrm->in_base;
 525   i = (size_t) rstrm->in_boundry % BYTES_PER_XDR_UNIT;
 526   where += i;
 527   len = rstrm->in_size - i;
 528   if ((len = (*(rstrm->readit)) (rstrm->tcp_handle, where, len)) == -1)
 529     return FALSE;
 530   rstrm->in_finger = where;
 531   where += len;
 532   rstrm->in_boundry = where;
 533   return TRUE;
 534 }
 535
 536 static bool_t   /* knows nothing about records!  Only about input buffers */
 537 internal_function
 538 get_input_bytes (RECSTREAM *rstrm, caddr_t addr, int len)
 539 {
 540   int current;
 541
 542   while (len > 0)
 543     {
 544       current = rstrm->in_boundry - rstrm->in_finger;
 545       if (current == 0)
 546         {
 547           if (!fill_input_buf (rstrm))
 548             return FALSE;
 549           continue;
 550         }
 551       current = (len < current) ? len : current;
 552       bcopy (rstrm->in_finger, addr, current);
 553       rstrm->in_finger += current;
 554       addr += current;
 555       len -= current;
 556     }
 557   return TRUE;
 558 }
 559
 560 static bool_t /* next two bytes of the input stream are treated as a header */
 561 internal_function
 562 set_input_fragment (RECSTREAM *rstrm)
 563 {
 564   u_long header;
 565
 566   if (!get_input_bytes (rstrm, (caddr_t) & header, BYTES_PER_XDR_UNIT))
 567     return FALSE;
 568   header = ntohl (header);
 569   rstrm->last_frag = ((header & LAST_FRAG) == 0) ? FALSE : TRUE;
 570   rstrm->fbtbc = header & ~LAST_FRAG;
 571   return TRUE;
 572 }
 573
 574 static bool_t   /* consumes input bytes; knows nothing about records! */
 575 internal_function
 576 skip_input_bytes (RECSTREAM *rstrm, long cnt)
 577 {
 578   int current;
 579
 580   while (cnt > 0)
 581     {
 582       current = rstrm->in_boundry - rstrm->in_finger;
 583       if (current == 0)
 584         {
 585           if (!fill_input_buf (rstrm))
 586             return FALSE;
 587           continue;
 588         }
 589       current = (cnt < current) ? cnt : current;
 590       rstrm->in_finger += current;
 591       cnt -= current;
 592     }
 593   return TRUE;
 594 }
 595
 596 static u_int
 597 internal_function
 598 fix_buf_size (u_int s)
 599 {
 600   if (s < 100)
 601     s = 4000;
 602   return RNDUP (s);
 603 }