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   /* We have to add the const since the `struct xdr_ops' in `struct XDR'
 173      is not `const'.  */
 174   xdrs->x_ops = (struct xdr_ops *) &xdrrec_ops;
 175   xdrs->x_private = (caddr_t) rstrm;
 176   rstrm->tcp_handle = tcp_handle;
 177   rstrm->readit = readit;
 178   rstrm->writeit = writeit;
 179   rstrm->out_finger = rstrm->out_boundry = rstrm->out_base;
 180   rstrm->frag_header = (u_int32_t *) rstrm->out_base;
 181   rstrm->out_finger += 4;
 182   rstrm->out_boundry += sendsize;
 183   rstrm->frag_sent = FALSE;
 184   rstrm->in_size = recvsize;
 185   rstrm->in_boundry = rstrm->in_base;
 186   rstrm->in_finger = (rstrm->in_boundry += recvsize);
 187   rstrm->fbtbc = 0;
 188   rstrm->last_frag = TRUE;
 189 }
 190
 191
 192 /*
 193  * The routines defined below are the xdr ops which will go into the
 194  * xdr handle filled in by xdrrec_create.
 195  */
 196
 197 static bool_t
 198 xdrrec_getlong (xdrs, lp)
 199      XDR *xdrs;
 200      long *lp;
 201 {
 202   RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
 203   int32_t *buflp = (int32_t *) rstrm->in_finger;
 204   int32_t mylong;
 205
 206   /* first try the inline, fast case */
 207   if (rstrm->fbtbc >= BYTES_PER_XDR_UNIT &&
 208       rstrm->in_boundry - (char *) buflp >= BYTES_PER_XDR_UNIT)
 209     {
 210       *lp = (int32_t) ntohl (*buflp);
 211       rstrm->fbtbc -= BYTES_PER_XDR_UNIT;
 212       rstrm->in_finger += BYTES_PER_XDR_UNIT;
 213     }
 214   else
 215     {
 216       if (!xdrrec_getbytes (xdrs, (caddr_t) & mylong,
 217                             BYTES_PER_XDR_UNIT))
 218         return FALSE;
 219       *lp = (int32_t) ntohl (mylong);
 220     }
 221   return TRUE;
 222 }
 223
 224 static bool_t
 225 xdrrec_putlong (xdrs, lp)
 226      XDR *xdrs;
 227      const long *lp;
 228 {
 229   RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
 230   int32_t *dest_lp = (int32_t *) rstrm->out_finger;
 231
 232   if ((rstrm->out_finger += BYTES_PER_XDR_UNIT) > rstrm->out_boundry)
 233     {
 234       /*
 235        * this case should almost never happen so the code is
 236        * inefficient
 237        */
 238       rstrm->out_finger -= BYTES_PER_XDR_UNIT;
 239       rstrm->frag_sent = TRUE;
 240       if (!flush_out (rstrm, FALSE))
 241         return FALSE;
 242       dest_lp = (int32_t *) rstrm->out_finger;
 243       rstrm->out_finger += BYTES_PER_XDR_UNIT;
 244     }
 245   *dest_lp = htonl (*lp);
 246   return TRUE;
 247 }
 248
 249 static bool_t                   /* must manage buffers, fragments, and records */
 250 xdrrec_getbytes (xdrs, addr, len)
 251      XDR *xdrs;
 252      caddr_t addr;
 253      u_int len;
 254 {
 255   RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
 256   u_int current;
 257
 258   while (len > 0)
 259     {
 260       current = rstrm->fbtbc;
 261       if (current == 0)
 262         {
 263           if (rstrm->last_frag)
 264             return FALSE;
 265           if (!set_input_fragment (rstrm))
 266             return FALSE;
 267           continue;
 268         }
 269       current = (len < current) ? len : current;
 270       if (!get_input_bytes (rstrm, addr, current))
 271         return FALSE;
 272       addr += current;
 273       rstrm->fbtbc -= current;
 274       len -= current;
 275     }
 276   return TRUE;
 277 }
 278
 279 static bool_t
 280 xdrrec_putbytes (xdrs, addr, len)
 281      XDR *xdrs;
 282      const char *addr;
 283      u_int len;
 284 {
 285   RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
 286   u_int current;
 287
 288   while (len > 0)
 289     {
 290       current = rstrm->out_boundry - rstrm->out_finger;
 291       current = (len < current) ? len : current;
 292       bcopy (addr, rstrm->out_finger, current);
 293       rstrm->out_finger += current;
 294       addr += current;
 295       len -= current;
 296       if (rstrm->out_finger == rstrm->out_boundry)
 297         {
 298           rstrm->frag_sent = TRUE;
 299           if (!flush_out (rstrm, FALSE))
 300             return FALSE;
 301         }
 302     }
 303   return TRUE;
 304 }
 305
 306 static u_int
 307 xdrrec_getpos (const XDR *xdrs)
 308 {
 309   RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
 310   long pos;
 311
 312   pos = lseek ((int) rstrm->tcp_handle, (long) 0, 1);
 313   if (pos != -1)
 314     switch (xdrs->x_op)
 315       {
 316
 317       case XDR_ENCODE:
 318         pos += rstrm->out_finger - rstrm->out_base;
 319         break;
 320
 321       case XDR_DECODE:
 322         pos -= rstrm->in_boundry - rstrm->in_finger;
 323         break;
 324
 325       default:
 326         pos = (u_int) - 1;
 327         break;
 328       }
 329   return (u_int) pos;
 330 }
 331
 332 static bool_t
 333 xdrrec_setpos (xdrs, pos)
 334      XDR *xdrs;
 335      u_int pos;
 336 {
 337   RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
 338   u_int currpos = xdrrec_getpos (xdrs);
 339   int delta = currpos - pos;
 340   caddr_t newpos;
 341
 342   if ((int) currpos != -1)
 343     switch (xdrs->x_op)
 344       {
 345
 346       case XDR_ENCODE:
 347         newpos = rstrm->out_finger - delta;
 348         if (newpos > (caddr_t) rstrm->frag_header &&
 349             newpos < rstrm->out_boundry)
 350           {
 351             rstrm->out_finger = newpos;
 352             return TRUE;
 353           }
 354         break;
 355
 356       case XDR_DECODE:
 357         newpos = rstrm->in_finger - delta;
 358         if ((delta < (int) (rstrm->fbtbc)) &&
 359             (newpos <= rstrm->in_boundry) &&
 360             (newpos >= rstrm->in_base))
 361           {
 362             rstrm->in_finger = newpos;
 363             rstrm->fbtbc -= delta;
 364             return TRUE;
 365           }
 366         break;
 367
 368       default:
 369         break;
 370       }
 371   return FALSE;
 372 }
 373
 374 static long *
 375 xdrrec_inline (XDR *xdrs, int len)
 376 {
 377   RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
 378   long *buf = NULL;
 379
 380   switch (xdrs->x_op)
 381     {
 382
 383     case XDR_ENCODE:
 384       if ((rstrm->out_finger + len) <= rstrm->out_boundry)
 385         {
 386           buf = (long *) rstrm->out_finger;
 387           rstrm->out_finger += len;
 388         }
 389       break;
 390
 391     case XDR_DECODE:
 392       if ((len <= rstrm->fbtbc) &&
 393           ((rstrm->in_finger + len) <= rstrm->in_boundry))
 394         {
 395           buf = (long *) rstrm->in_finger;
 396           rstrm->fbtbc -= len;
 397           rstrm->in_finger += len;
 398         }
 399       break;
 400
 401     default:
 402       break;
 403     }
 404   return buf;
 405 }
 406
 407 static void
 408 xdrrec_destroy (xdrs)
 409      XDR *xdrs;
 410 {
 411   RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
 412
 413   mem_free (rstrm->the_buffer,
 414             rstrm->sendsize + rstrm->recvsize + BYTES_PER_XDR_UNIT);
 415   mem_free ((caddr_t) rstrm, sizeof (RECSTREAM));
 416 }
 417
 418
 419 /*
 420  * Exported routines to manage xdr records
 421  */
 422
 423 /*
 424  * Before reading (deserializing from the stream, one should always call
 425  * this procedure to guarantee proper record alignment.
 426  */
 427 bool_t
 428 xdrrec_skiprecord (xdrs)
 429      XDR *xdrs;
 430 {
 431   RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
 432
 433   while (rstrm->fbtbc > 0 || (!rstrm->last_frag))
 434     {
 435       if (!skip_input_bytes (rstrm, rstrm->fbtbc))
 436         return FALSE;
 437       rstrm->fbtbc = 0;
 438       if ((!rstrm->last_frag) && (!set_input_fragment (rstrm)))
 439         return FALSE;
 440     }
 441   rstrm->last_frag = FALSE;
 442   return TRUE;
 443 }
 444
 445 /*
 446  * Lookahead function.
 447  * Returns TRUE iff there is no more input in the buffer
 448  * after consuming the rest of the current record.
 449  */
 450 bool_t
 451 xdrrec_eof (xdrs)
 452      XDR *xdrs;
 453 {
 454   RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
 455
 456   while (rstrm->fbtbc > 0 || (!rstrm->last_frag))
 457     {
 458       if (!skip_input_bytes (rstrm, rstrm->fbtbc))
 459         return TRUE;
 460       rstrm->fbtbc = 0;
 461       if ((!rstrm->last_frag) && (!set_input_fragment (rstrm)))
 462         return TRUE;
 463     }
 464   if (rstrm->in_finger == rstrm->in_boundry)
 465     return TRUE;
 466   return FALSE;
 467 }
 468
 469 /*
 470  * The client must tell the package when an end-of-record has occurred.
 471  * The second parameter tells whether the record should be flushed to the
 472  * (output) tcp stream.  (This lets the package support batched or
 473  * pipelined procedure calls.)  TRUE => immediate flush to tcp connection.
 474  */
 475 bool_t
 476 xdrrec_endofrecord (xdrs, sendnow)
 477      XDR *xdrs;
 478      bool_t sendnow;
 479 {
 480   RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
 481   u_long len;           /* fragment length */
 482
 483   if (sendnow || rstrm->frag_sent
 484       || rstrm->out_finger + BYTES_PER_XDR_UNIT >= rstrm->out_boundry)
 485     {
 486       rstrm->frag_sent = FALSE;
 487       return flush_out (rstrm, TRUE);
 488     }
 489   len = (rstrm->out_finger - (char *) rstrm->frag_header
 490          - BYTES_PER_XDR_UNIT);
 491   *rstrm->frag_header = htonl ((u_long) len | LAST_FRAG);
 492   rstrm->frag_header = (u_int32_t *) rstrm->out_finger;
 493   rstrm->out_finger += BYTES_PER_XDR_UNIT;
 494   return TRUE;
 495 }
 496
 497
 498 /*
 499  * Internal useful routines
 500  */
 501 static bool_t
 502 internal_function
 503 flush_out (RECSTREAM *rstrm, bool_t eor)
 504 {
 505   u_long eormask = (eor == TRUE) ? LAST_FRAG : 0;
 506   u_long len = (rstrm->out_finger - (char *) rstrm->frag_header
 507                 - BYTES_PER_XDR_UNIT);
 508
 509   *rstrm->frag_header = htonl (len | eormask);
 510   len = rstrm->out_finger - rstrm->out_base;
 511   if ((*(rstrm->writeit)) (rstrm->tcp_handle, rstrm->out_base, (int) len)
 512       != (int) len)
 513     return FALSE;
 514   rstrm->frag_header = (u_int32_t *) rstrm->out_base;
 515   rstrm->out_finger = (caddr_t) rstrm->out_base + BYTES_PER_XDR_UNIT;
 516   return TRUE;
 517 }
 518
 519 static bool_t   /* knows nothing about records!  Only about input buffers */
 520 fill_input_buf (RECSTREAM *rstrm)
 521 {
 522   caddr_t where;
 523   size_t i;
 524   int len;
 525
 526   where = rstrm->in_base;
 527   i = (size_t) rstrm->in_boundry % BYTES_PER_XDR_UNIT;
 528   where += i;
 529   len = rstrm->in_size - i;
 530   if ((len = (*(rstrm->readit)) (rstrm->tcp_handle, where, len)) == -1)
 531     return FALSE;
 532   rstrm->in_finger = where;
 533   where += len;
 534   rstrm->in_boundry = where;
 535   return TRUE;
 536 }
 537
 538 static bool_t   /* knows nothing about records!  Only about input buffers */
 539 internal_function
 540 get_input_bytes (RECSTREAM *rstrm, caddr_t addr, int len)
 541 {
 542   int current;
 543
 544   while (len > 0)
 545     {
 546       current = rstrm->in_boundry - rstrm->in_finger;
 547       if (current == 0)
 548         {
 549           if (!fill_input_buf (rstrm))
 550             return FALSE;
 551           continue;
 552         }
 553       current = (len < current) ? len : current;
 554       bcopy (rstrm->in_finger, addr, current);
 555       rstrm->in_finger += current;
 556       addr += current;
 557       len -= current;
 558     }
 559   return TRUE;
 560 }
 561
 562 static bool_t /* next two bytes of the input stream are treated as a header */
 563 internal_function
 564 set_input_fragment (RECSTREAM *rstrm)
 565 {
 566   u_long header;
 567
 568   if (! get_input_bytes (rstrm, (caddr_t)&header, BYTES_PER_XDR_UNIT))
 569     return FALSE;
 570   header = ntohl (header);
 571   rstrm->last_frag = ((header & LAST_FRAG) == 0) ? FALSE : TRUE;
 572   /*
 573    * Sanity check. Try not to accept wildly incorrect
 574    * record sizes. Unfortunately, the only record size
 575    * we can positively identify as being 'wildly incorrect'
 576    * is zero.  Ridiculously large record sizes may look wrong,
 577    * but we don't have any way to be certain that they aren't
 578    * what the client actually intended to send us.
 579    */
 580   if ((header & (~LAST_FRAG)) == 0)
 581     return FALSE;
 582   rstrm->fbtbc = header & ~LAST_FRAG;
 583   return TRUE;
 584 }
 585
 586 static bool_t   /* consumes input bytes; knows nothing about records! */
 587 internal_function
 588 skip_input_bytes (RECSTREAM *rstrm, long cnt)
 589 {
 590   int current;
 591
 592   while (cnt > 0)
 593     {
 594       current = rstrm->in_boundry - rstrm->in_finger;
 595       if (current == 0)
 596         {
 597           if (!fill_input_buf (rstrm))
 598             return FALSE;
 599           continue;
 600         }
 601       current = (cnt < current) ? cnt : current;
 602       rstrm->in_finger += current;
 603       cnt -= current;
 604     }
 605   return TRUE;
 606 }
 607
 608 static u_int
 609 internal_function
 610 fix_buf_size (u_int s)
 611 {
 612   if (s < 100)
 613     s = 4000;
 614   return RNDUP (s);
 615 }