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 #ifdef USE_IN_LIBIO
  57 # include <libio/iolibio.h>
  58 # define fputs(s, f) _IO_fputs (s, f)
  59 #endif
  60
  61 static bool_t xdrrec_getlong (XDR *, long *);
  62 static bool_t xdrrec_putlong (XDR *, const long *);
  63 static bool_t xdrrec_getbytes (XDR *, caddr_t, u_int);
  64 static bool_t xdrrec_putbytes (XDR *, const char *, u_int);
  65 static u_int xdrrec_getpos (const XDR *);
  66 static bool_t xdrrec_setpos (XDR *, u_int);
  67 static long *xdrrec_inline (XDR *, int);
  68 static void xdrrec_destroy (XDR *);
  69
  70 static const struct xdr_ops xdrrec_ops =
  71 {
  72   xdrrec_getlong,
  73   xdrrec_putlong,
  74   xdrrec_getbytes,
  75   xdrrec_putbytes,
  76   xdrrec_getpos,
  77   xdrrec_setpos,
  78   xdrrec_inline,
  79   xdrrec_destroy
  80 };
  81
  82 /*
  83  * A record is composed of one or more record fragments.
  84  * A record fragment is a two-byte header followed by zero to
  85  * 2**32-1 bytes.  The header is treated as a long unsigned and is
  86  * encode/decoded to the network via htonl/ntohl.  The low order 31 bits
  87  * are a byte count of the fragment.  The highest order bit is a boolean:
  88  * 1 => this fragment is the last fragment of the record,
  89  * 0 => this fragment is followed by more fragment(s).
  90  *
  91  * The fragment/record machinery is not general;  it is constructed to
  92  * meet the needs of xdr and rpc based on tcp.
  93  */
  94
  95 #define LAST_FRAG (1UL << 31)
  96
  97 typedef struct rec_strm
  98   {
  99     caddr_t tcp_handle;
 100     caddr_t the_buffer;
 101     /*
 102      * out-going bits
 103      */
 104     int (*writeit) (char *, char *, int);
 105     caddr_t out_base;           /* output buffer (points to frag header) */
 106     caddr_t out_finger;         /* next output position */
 107     caddr_t out_boundry;        /* data cannot up to this address */
 108     u_int32_t *frag_header;     /* beginning of curren fragment */
 109     bool_t frag_sent;           /* true if buffer sent in middle of record */
 110     /*
 111      * in-coming bits
 112      */
 113     int (*readit) (char *, char *, int);
 114     u_long in_size;             /* fixed size of the input buffer */
 115     caddr_t in_base;
 116     caddr_t in_finger;          /* location of next byte to be had */
 117     caddr_t in_boundry;         /* can read up to this location */
 118     long fbtbc;                 /* fragment bytes to be consumed */
 119     bool_t last_frag;
 120     u_int sendsize;
 121     u_int recvsize;
 122   }
 123 RECSTREAM;
 124
 125 static u_int fix_buf_size (u_int) internal_function;
 126 static bool_t skip_input_bytes (RECSTREAM *, long) internal_function;
 127 static bool_t flush_out (RECSTREAM *, bool_t) internal_function;
 128 static bool_t set_input_fragment (RECSTREAM *) internal_function;
 129 static bool_t get_input_bytes (RECSTREAM *, caddr_t, int) internal_function;
 130
 131 /*
 132  * Create an xdr handle for xdrrec
 133  * xdrrec_create fills in xdrs.  Sendsize and recvsize are
 134  * send and recv buffer sizes (0 => use default).
 135  * tcp_handle is an opaque handle that is passed as the first parameter to
 136  * the procedures readit and writeit.  Readit and writeit are read and
 137  * write respectively.   They are like the system
 138  * calls expect that they take an opaque handle rather than an fd.
 139  */
 140 void
 141 xdrrec_create (XDR *xdrs, u_int sendsize,
 142                u_int recvsize, caddr_t tcp_handle,
 143                int (*readit) (char *, char *, int),
 144                int (*writeit) (char *, char *, int))
 145 {
 146   RECSTREAM *rstrm = (RECSTREAM *) mem_alloc (sizeof (RECSTREAM));
 147   caddr_t tmp;
 148
 149   if (rstrm == NULL)
 150     {
 151       (void) fputs (_("xdrrec_create: out of memory\n"), stderr);
 152       /*
 153        *  This is bad.  Should rework xdrrec_create to
 154        *  return a handle, and in this case return NULL
 155        */
 156       return;
 157     }
 158   /*
 159    * adjust sizes and allocate buffer quad byte aligned
 160    */
 161   rstrm->sendsize = sendsize = fix_buf_size (sendsize);
 162   rstrm->recvsize = recvsize = fix_buf_size (recvsize);
 163   rstrm->the_buffer = mem_alloc (sendsize + recvsize + BYTES_PER_XDR_UNIT);
 164   if (rstrm->the_buffer == NULL)
 165     {
 166       (void) fputs (_("xdrrec_create: out of memory\n"), stderr);
 167       return;
 168     }
 169   tmp = rstrm->the_buffer;
 170   if ((size_t)tmp % BYTES_PER_XDR_UNIT)
 171     tmp += BYTES_PER_XDR_UNIT - (size_t)tmp % BYTES_PER_XDR_UNIT;
 172   rstrm->out_base = tmp;
 173   rstrm->in_base = tmp + sendsize;
 174   /*
 175    * now the rest ...
 176    */
 177   /* We have to add the const since the `struct xdr_ops' in `struct XDR'
 178      is not `const'.  */
 179   xdrs->x_ops = (struct xdr_ops *) &xdrrec_ops;
 180   xdrs->x_private = (caddr_t) rstrm;
 181   rstrm->tcp_handle = tcp_handle;
 182   rstrm->readit = readit;
 183   rstrm->writeit = writeit;
 184   rstrm->out_finger = rstrm->out_boundry = rstrm->out_base;
 185   rstrm->frag_header = (u_int32_t *) rstrm->out_base;
 186   rstrm->out_finger += 4;
 187   rstrm->out_boundry += sendsize;
 188   rstrm->frag_sent = FALSE;
 189   rstrm->in_size = recvsize;
 190   rstrm->in_boundry = rstrm->in_base;
 191   rstrm->in_finger = (rstrm->in_boundry += recvsize);
 192   rstrm->fbtbc = 0;
 193   rstrm->last_frag = TRUE;
 194 }
 195
 196
 197 /*
 198  * The routines defined below are the xdr ops which will go into the
 199  * xdr handle filled in by xdrrec_create.
 200  */
 201
 202 static bool_t
 203 xdrrec_getlong (xdrs, lp)
 204      XDR *xdrs;
 205      long *lp;
 206 {
 207   RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
 208   int32_t *buflp = (int32_t *) rstrm->in_finger;
 209   int32_t mylong;
 210
 211   /* first try the inline, fast case */
 212   if (rstrm->fbtbc >= BYTES_PER_XDR_UNIT &&
 213       rstrm->in_boundry - (char *) buflp >= BYTES_PER_XDR_UNIT)
 214     {
 215       *lp = (int32_t) ntohl (*buflp);
 216       rstrm->fbtbc -= BYTES_PER_XDR_UNIT;
 217       rstrm->in_finger += BYTES_PER_XDR_UNIT;
 218     }
 219   else
 220     {
 221       if (!xdrrec_getbytes (xdrs, (caddr_t) & mylong,
 222                             BYTES_PER_XDR_UNIT))
 223         return FALSE;
 224       *lp = (int32_t) ntohl (mylong);
 225     }
 226   return TRUE;
 227 }
 228
 229 static bool_t
 230 xdrrec_putlong (xdrs, lp)
 231      XDR *xdrs;
 232      const long *lp;
 233 {
 234   RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
 235   int32_t *dest_lp = (int32_t *) rstrm->out_finger;
 236
 237   if ((rstrm->out_finger += BYTES_PER_XDR_UNIT) > rstrm->out_boundry)
 238     {
 239       /*
 240        * this case should almost never happen so the code is
 241        * inefficient
 242        */
 243       rstrm->out_finger -= BYTES_PER_XDR_UNIT;
 244       rstrm->frag_sent = TRUE;
 245       if (!flush_out (rstrm, FALSE))
 246         return FALSE;
 247       dest_lp = (int32_t *) rstrm->out_finger;
 248       rstrm->out_finger += BYTES_PER_XDR_UNIT;
 249     }
 250   *dest_lp = htonl (*lp);
 251   return TRUE;
 252 }
 253
 254 static bool_t                   /* must manage buffers, fragments, and records */
 255 xdrrec_getbytes (xdrs, addr, len)
 256      XDR *xdrs;
 257      caddr_t addr;
 258      u_int len;
 259 {
 260   RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
 261   u_int current;
 262
 263   while (len > 0)
 264     {
 265       current = rstrm->fbtbc;
 266       if (current == 0)
 267         {
 268           if (rstrm->last_frag)
 269             return FALSE;
 270           if (!set_input_fragment (rstrm))
 271             return FALSE;
 272           continue;
 273         }
 274       current = (len < current) ? len : current;
 275       if (!get_input_bytes (rstrm, addr, current))
 276         return FALSE;
 277       addr += current;
 278       rstrm->fbtbc -= current;
 279       len -= current;
 280     }
 281   return TRUE;
 282 }
 283
 284 static bool_t
 285 xdrrec_putbytes (xdrs, addr, len)
 286      XDR *xdrs;
 287      const char *addr;
 288      u_int len;
 289 {
 290   RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
 291   u_int current;
 292
 293   while (len > 0)
 294     {
 295       current = rstrm->out_boundry - rstrm->out_finger;
 296       current = (len < current) ? len : current;
 297       bcopy (addr, rstrm->out_finger, current);
 298       rstrm->out_finger += current;
 299       addr += current;
 300       len -= current;
 301       if (rstrm->out_finger == rstrm->out_boundry)
 302         {
 303           rstrm->frag_sent = TRUE;
 304           if (!flush_out (rstrm, FALSE))
 305             return FALSE;
 306         }
 307     }
 308   return TRUE;
 309 }
 310
 311 static u_int
 312 xdrrec_getpos (const XDR *xdrs)
 313 {
 314   RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
 315   long pos;
 316
 317   pos = __lseek ((int) rstrm->tcp_handle, (long) 0, 1);
 318   if (pos != -1)
 319     switch (xdrs->x_op)
 320       {
 321
 322       case XDR_ENCODE:
 323         pos += rstrm->out_finger - rstrm->out_base;
 324         break;
 325
 326       case XDR_DECODE:
 327         pos -= rstrm->in_boundry - rstrm->in_finger;
 328         break;
 329
 330       default:
 331         pos = (u_int) - 1;
 332         break;
 333       }
 334   return (u_int) pos;
 335 }
 336
 337 static bool_t
 338 xdrrec_setpos (xdrs, pos)
 339      XDR *xdrs;
 340      u_int pos;
 341 {
 342   RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
 343   u_int currpos = xdrrec_getpos (xdrs);
 344   int delta = currpos - pos;
 345   caddr_t newpos;
 346
 347   if ((int) currpos != -1)
 348     switch (xdrs->x_op)
 349       {
 350
 351       case XDR_ENCODE:
 352         newpos = rstrm->out_finger - delta;
 353         if (newpos > (caddr_t) rstrm->frag_header &&
 354             newpos < rstrm->out_boundry)
 355           {
 356             rstrm->out_finger = newpos;
 357             return TRUE;
 358           }
 359         break;
 360
 361       case XDR_DECODE:
 362         newpos = rstrm->in_finger - delta;
 363         if ((delta < (int) (rstrm->fbtbc)) &&
 364             (newpos <= rstrm->in_boundry) &&
 365             (newpos >= rstrm->in_base))
 366           {
 367             rstrm->in_finger = newpos;
 368             rstrm->fbtbc -= delta;
 369             return TRUE;
 370           }
 371         break;
 372
 373       default:
 374         break;
 375       }
 376   return FALSE;
 377 }
 378
 379 static long *
 380 xdrrec_inline (XDR *xdrs, int len)
 381 {
 382   RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
 383   long *buf = NULL;
 384
 385   switch (xdrs->x_op)
 386     {
 387
 388     case XDR_ENCODE:
 389       if ((rstrm->out_finger + len) <= rstrm->out_boundry)
 390         {
 391           buf = (long *) rstrm->out_finger;
 392           rstrm->out_finger += len;
 393         }
 394       break;
 395
 396     case XDR_DECODE:
 397       if ((len <= rstrm->fbtbc) &&
 398           ((rstrm->in_finger + len) <= rstrm->in_boundry))
 399         {
 400           buf = (long *) rstrm->in_finger;
 401           rstrm->fbtbc -= len;
 402           rstrm->in_finger += len;
 403         }
 404       break;
 405
 406     default:
 407       break;
 408     }
 409   return buf;
 410 }
 411
 412 static void
 413 xdrrec_destroy (xdrs)
 414      XDR *xdrs;
 415 {
 416   RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
 417
 418   mem_free (rstrm->the_buffer,
 419             rstrm->sendsize + rstrm->recvsize + BYTES_PER_XDR_UNIT);
 420   mem_free ((caddr_t) rstrm, sizeof (RECSTREAM));
 421 }
 422
 423
 424 /*
 425  * Exported routines to manage xdr records
 426  */
 427
 428 /*
 429  * Before reading (deserializing from the stream, one should always call
 430  * this procedure to guarantee proper record alignment.
 431  */
 432 bool_t
 433 xdrrec_skiprecord (xdrs)
 434      XDR *xdrs;
 435 {
 436   RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
 437
 438   while (rstrm->fbtbc > 0 || (!rstrm->last_frag))
 439     {
 440       if (!skip_input_bytes (rstrm, rstrm->fbtbc))
 441         return FALSE;
 442       rstrm->fbtbc = 0;
 443       if ((!rstrm->last_frag) && (!set_input_fragment (rstrm)))
 444         return FALSE;
 445     }
 446   rstrm->last_frag = FALSE;
 447   return TRUE;
 448 }
 449
 450 /*
 451  * Lookahead function.
 452  * Returns TRUE iff there is no more input in the buffer
 453  * after consuming the rest of the current record.
 454  */
 455 bool_t
 456 xdrrec_eof (xdrs)
 457      XDR *xdrs;
 458 {
 459   RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
 460
 461   while (rstrm->fbtbc > 0 || (!rstrm->last_frag))
 462     {
 463       if (!skip_input_bytes (rstrm, rstrm->fbtbc))
 464         return TRUE;
 465       rstrm->fbtbc = 0;
 466       if ((!rstrm->last_frag) && (!set_input_fragment (rstrm)))
 467         return TRUE;
 468     }
 469   if (rstrm->in_finger == rstrm->in_boundry)
 470     return TRUE;
 471   return FALSE;
 472 }
 473
 474 /*
 475  * The client must tell the package when an end-of-record has occurred.
 476  * The second parameter tells whether the record should be flushed to the
 477  * (output) tcp stream.  (This lets the package support batched or
 478  * pipelined procedure calls.)  TRUE => immediate flush to tcp connection.
 479  */
 480 bool_t
 481 xdrrec_endofrecord (xdrs, sendnow)
 482      XDR *xdrs;
 483      bool_t sendnow;
 484 {
 485   RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
 486   u_long len;           /* fragment length */
 487
 488   if (sendnow || rstrm->frag_sent
 489       || rstrm->out_finger + BYTES_PER_XDR_UNIT >= rstrm->out_boundry)
 490     {
 491       rstrm->frag_sent = FALSE;
 492       return flush_out (rstrm, TRUE);
 493     }
 494   len = (rstrm->out_finger - (char *) rstrm->frag_header
 495          - BYTES_PER_XDR_UNIT);
 496   *rstrm->frag_header = htonl ((u_long) len | LAST_FRAG);
 497   rstrm->frag_header = (u_int32_t *) rstrm->out_finger;
 498   rstrm->out_finger += BYTES_PER_XDR_UNIT;
 499   return TRUE;
 500 }
 501
 502
 503 /*
 504  * Internal useful routines
 505  */
 506 static bool_t
 507 internal_function
 508 flush_out (RECSTREAM *rstrm, bool_t eor)
 509 {
 510   u_long eormask = (eor == TRUE) ? LAST_FRAG : 0;
 511   u_long len = (rstrm->out_finger - (char *) rstrm->frag_header
 512                 - BYTES_PER_XDR_UNIT);
 513
 514   *rstrm->frag_header = htonl (len | eormask);
 515   len = rstrm->out_finger - rstrm->out_base;
 516   if ((*(rstrm->writeit)) (rstrm->tcp_handle, rstrm->out_base, (int) len)
 517       != (int) len)
 518     return FALSE;
 519   rstrm->frag_header = (u_int32_t *) rstrm->out_base;
 520   rstrm->out_finger = (caddr_t) rstrm->out_base + BYTES_PER_XDR_UNIT;
 521   return TRUE;
 522 }
 523
 524 static bool_t   /* knows nothing about records!  Only about input buffers */
 525 fill_input_buf (RECSTREAM *rstrm)
 526 {
 527   caddr_t where;
 528   size_t i;
 529   int len;
 530
 531   where = rstrm->in_base;
 532   i = (size_t) rstrm->in_boundry % BYTES_PER_XDR_UNIT;
 533   where += i;
 534   len = rstrm->in_size - i;
 535   if ((len = (*(rstrm->readit)) (rstrm->tcp_handle, where, len)) == -1)
 536     return FALSE;
 537   rstrm->in_finger = where;
 538   where += len;
 539   rstrm->in_boundry = where;
 540   return TRUE;
 541 }
 542
 543 static bool_t   /* knows nothing about records!  Only about input buffers */
 544 internal_function
 545 get_input_bytes (RECSTREAM *rstrm, caddr_t addr, int len)
 546 {
 547   int current;
 548
 549   while (len > 0)
 550     {
 551       current = rstrm->in_boundry - rstrm->in_finger;
 552       if (current == 0)
 553         {
 554           if (!fill_input_buf (rstrm))
 555             return FALSE;
 556           continue;
 557         }
 558       current = (len < current) ? len : current;
 559       bcopy (rstrm->in_finger, addr, current);
 560       rstrm->in_finger += current;
 561       addr += current;
 562       len -= current;
 563     }
 564   return TRUE;
 565 }
 566
 567 static bool_t /* next two bytes of the input stream are treated as a header */
 568 internal_function
 569 set_input_fragment (RECSTREAM *rstrm)
 570 {
 571   u_long header;
 572
 573   if (! get_input_bytes (rstrm, (caddr_t)&header, BYTES_PER_XDR_UNIT))
 574     return FALSE;
 575   header = ntohl (header);
 576   rstrm->last_frag = ((header & LAST_FRAG) == 0) ? FALSE : TRUE;
 577   /*
 578    * Sanity check. Try not to accept wildly incorrect
 579    * record sizes. Unfortunately, the only record size
 580    * we can positively identify as being 'wildly incorrect'
 581    * is zero.  Ridiculously large record sizes may look wrong,
 582    * but we don't have any way to be certain that they aren't
 583    * what the client actually intended to send us.
 584    */
 585   if ((header & (~LAST_FRAG)) == 0)
 586     return FALSE;
 587   rstrm->fbtbc = header & ~LAST_FRAG;
 588   return TRUE;
 589 }
 590
 591 static bool_t   /* consumes input bytes; knows nothing about records! */
 592 internal_function
 593 skip_input_bytes (RECSTREAM *rstrm, long cnt)
 594 {
 595   int current;
 596
 597   while (cnt > 0)
 598     {
 599       current = rstrm->in_boundry - rstrm->in_finger;
 600       if (current == 0)
 601         {
 602           if (!fill_input_buf (rstrm))
 603             return FALSE;
 604           continue;
 605         }
 606       current = (cnt < current) ? cnt : current;
 607       rstrm->in_finger += current;
 608       cnt -= current;
 609     }
 610   return TRUE;
 611 }
 612
 613 static u_int
 614 internal_function
 615 fix_buf_size (u_int s)
 616 {
 617   if (s < 100)
 618     s = 4000;
 619   return RNDUP (s);
 620 }