libc/inet/rpc/xdr_rec.c

   1 /*
   2  * Sun RPC is a product of Sun Microsystems, Inc. and is provided for
   3  * unrestricted use provided that this legend is included on all tape
   4  * media and as a part of the software program in whole or part.  Users
   5  * may copy or modify Sun RPC without charge, but are not authorized
   6  * to license or distribute it to anyone else except as part of a product or
   7  * program developed by the user.
   8  *
   9  * SUN RPC IS PROVIDED AS IS WITH NO WARRANTIES OF ANY KIND INCLUDING THE
  10  * WARRANTIES OF DESIGN, MERCHANTIBILITY AND FITNESS FOR A PARTICULAR
  11  * PURPOSE, OR ARISING FROM A COURSE OF DEALING, USAGE OR TRADE PRACTICE.
  12  *
  13  * Sun RPC is provided with no support and without any obligation on the
  14  * part of Sun Microsystems, Inc. to assist in its use, correction,
  15  * modification or enhancement.
  16  *
  17  * SUN MICROSYSTEMS, INC. SHALL HAVE NO LIABILITY WITH RESPECT TO THE
  18  * INFRINGEMENT OF COPYRIGHTS, TRADE SECRETS OR ANY PATENTS BY SUN RPC
  19  * OR ANY PART THEREOF.
  20  *
  21  * In no event will Sun Microsystems, Inc. be liable for any lost revenue
  22  * or profits or other special, indirect and consequential damages, even if
  23  * Sun has been advised of the possibility of such damages.
  24  *
  25  * Sun Microsystems, Inc.
  26  * 2550 Garcia Avenue
  27  * Mountain View, California  94043
  28  */
  29
  30 /*
  31  * xdr_rec.c, Implements TCP/IP based XDR streams with a "record marking"
  32  * layer above tcp (for rpc's use).
  33  *
  34  * Copyright (C) 1984, Sun Microsystems, Inc.
  35  *
  36  * These routines interface XDRSTREAMS to a tcp/ip connection.
  37  * There is a record marking layer between the xdr stream
  38  * and the tcp transport level.  A record is composed on one or more
  39  * record fragments.  A record fragment is a thirty-two bit header followed
  40  * by n bytes of data, where n is contained in the header.  The header
  41  * is represented as a htonl(u_long).  The high order bit encodes
  42  * whether or not the fragment is the last fragment of the record
  43  * (1 => fragment is last, 0 => more fragments to follow.
  44  * The other 31 bits encode the byte length of the fragment.
  45  */
  46
  47 #include <stdio.h>
  48 #include <string.h>
  49 #include <unistd.h>
  50 #include "rpc_private.h"
  51
  52 static bool_t xdrrec_getbytes (XDR *, caddr_t, u_int);
  53 static bool_t xdrrec_putbytes (XDR *, const char *, u_int);
  54 static bool_t xdrrec_getint32 (XDR *, int32_t *);
  55 static bool_t xdrrec_putint32 (XDR *, const int32_t *);
  56 #if ULONG_MAX != 0xffffffff
  57 static bool_t xdrrec_getlong (XDR *, long *);
  58 static bool_t xdrrec_putlong (XDR *, const long *);
  59 #endif
  60 static u_int xdrrec_getpos (const XDR *);
  61 static bool_t xdrrec_setpos (XDR *, u_int);
  62 static int32_t *xdrrec_inline (XDR *, u_int);
  63 static void xdrrec_destroy (XDR *);
  64
  65 static const struct xdr_ops xdrrec_ops = {
  66 #if ULONG_MAX == 0xffffffff
  67   (bool_t (*)(XDR *, long *)) xdrrec_getint32,
  68   (bool_t (*)(XDR *, const long *)) xdrrec_putint32,
  69 #else
  70   xdrrec_getlong,
  71   xdrrec_putlong,
  72 #endif
  73   xdrrec_getbytes,
  74   xdrrec_putbytes,
  75   xdrrec_getpos,
  76   xdrrec_setpos,
  77   xdrrec_inline,
  78   xdrrec_destroy,
  79   xdrrec_getint32,
  80   xdrrec_putint32
  81 };
  82
  83 /*
  84  * A record is composed of one or more record fragments.
  85  * A record fragment is a two-byte header followed by zero to
  86  * 2**32-1 bytes.  The header is treated as a long unsigned and is
  87  * encode/decoded to the network via htonl/ntohl.  The low order 31 bits
  88  * are a byte count of the fragment.  The highest order bit is a boolean:
  89  * 1 => this fragment is the last fragment of the record,
  90  * 0 => this fragment is followed by more fragment(s).
  91  *
  92  * The fragment/record machinery is not general;  it is constructed to
  93  * meet the needs of xdr and rpc based on tcp.
  94  */
  95
  96 #define LAST_FRAG (1UL << 31)
  97
  98 typedef struct rec_strm
  99   {
 100     caddr_t tcp_handle;
 101     caddr_t the_buffer;
 102     /*
 103      * out-going bits
 104      */
 105     int (*writeit) (char *, char *, int);
 106     caddr_t out_base;           /* output buffer (points to frag header) */
 107     caddr_t out_finger;         /* next output position */
 108     caddr_t out_boundry;        /* data cannot up to this address */
 109     u_int32_t *frag_header;     /* beginning of curren fragment */
 110     bool_t frag_sent;           /* true if buffer sent in middle of record */
 111     /*
 112      * in-coming bits
 113      */
 114     int (*readit) (char *, char *, int);
 115     u_long in_size;             /* fixed size of the input buffer */
 116     caddr_t in_base;
 117     caddr_t in_finger;          /* location of next byte to be had */
 118     caddr_t in_boundry;         /* can read up to this location */
 119     long fbtbc;                 /* fragment bytes to be consumed */
 120     bool_t last_frag;
 121     u_int sendsize;
 122     u_int recvsize;
 123   }
 124 RECSTREAM;
 125
 126 static u_int fix_buf_size (u_int) internal_function;
 127 static bool_t skip_input_bytes (RECSTREAM *, long) internal_function;
 128 static bool_t flush_out (RECSTREAM *, bool_t) internal_function;
 129 static bool_t set_input_fragment (RECSTREAM *) internal_function;
 130 static bool_t get_input_bytes (RECSTREAM *, caddr_t, int) internal_function;
 131
 132 /*
 133  * Create an xdr handle for xdrrec
 134  * xdrrec_create fills in xdrs.  Sendsize and recvsize are
 135  * send and recv buffer sizes (0 => use default).
 136  * tcp_handle is an opaque handle that is passed as the first parameter to
 137  * the procedures readit and writeit.  Readit and writeit are read and
 138  * write respectively.   They are like the system
 139  * calls expect that they take an opaque handle rather than an fd.
 140  */
 141 void
 142 xdrrec_create (XDR *xdrs, u_int sendsize,
 143                u_int recvsize, caddr_t tcp_handle,
 144                int (*readit) (char *, char *, int),
 145                int (*writeit) (char *, char *, int))
 146 {
 147   RECSTREAM *rstrm = (RECSTREAM *) mem_alloc (sizeof (RECSTREAM));
 148   caddr_t tmp;
 149   char *buf;
 150
 151   sendsize = fix_buf_size (sendsize);
 152   recvsize = fix_buf_size (recvsize);
 153   buf = mem_alloc (sendsize + recvsize + BYTES_PER_XDR_UNIT);
 154
 155   if (rstrm == NULL || buf == NULL)
 156     {
 157       (void) fputs ("xdrrec_create: out of memory\n", stderr);
 158       mem_free (rstrm, sizeof (RECSTREAM));
 159       mem_free (buf, sendsize + recvsize + BYTES_PER_XDR_UNIT);
 160       /*
 161        *  This is bad.  Should rework xdrrec_create to
 162        *  return a handle, and in this case return NULL
 163        */
 164       return;
 165     }
 166   /*
 167    * adjust sizes and allocate buffer quad byte aligned
 168    */
 169   rstrm->sendsize = sendsize;
 170   rstrm->recvsize = recvsize;
 171   rstrm->the_buffer = buf;
 172   tmp = rstrm->the_buffer;
 173   if ((size_t)tmp % BYTES_PER_XDR_UNIT)
 174     tmp += BYTES_PER_XDR_UNIT - (size_t)tmp % BYTES_PER_XDR_UNIT;
 175   rstrm->out_base = tmp;
 176   rstrm->in_base = tmp + sendsize;
 177   /*
 178    * now the rest ...
 179    */
 180   xdrs->x_ops = &xdrrec_ops;
 181   xdrs->x_private = (caddr_t) rstrm;
 182   rstrm->tcp_handle = tcp_handle;
 183   rstrm->readit = readit;
 184   rstrm->writeit = writeit;
 185   rstrm->out_finger = rstrm->out_boundry = rstrm->out_base;
 186   rstrm->frag_header = (u_int32_t *) rstrm->out_base;
 187   rstrm->out_finger += 4;
 188   rstrm->out_boundry += sendsize;
 189   rstrm->frag_sent = FALSE;
 190   rstrm->in_size = recvsize;
 191   rstrm->in_boundry = rstrm->in_base;
 192   rstrm->in_finger = (rstrm->in_boundry += recvsize);
 193   rstrm->fbtbc = 0;
 194   rstrm->last_frag = TRUE;
 195 }
 196 libc_hidden_def(xdrrec_create)
 197
 198
 199 /*
 200  * The routines defined below are the xdr ops which will go into the
 201  * xdr handle filled in by xdrrec_create.
 202  */
 203
 204 static bool_t
 205 xdrrec_getint32 (XDR *xdrs, int32_t *ip)
 206 {
 207   RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
 208   int32_t *bufip = (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 *) bufip >= BYTES_PER_XDR_UNIT)
 214     {
 215       *ip = ntohl (*bufip);
 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       *ip = ntohl (mylong);
 225     }
 226   return TRUE;
 227 }
 228
 229 #if ULONG_MAX != 0xffffffff
 230 static bool_t
 231 xdrrec_getlong (XDR *xdrs, long *lp)
 232 {
 233   int32_t v;
 234   bool_t r = xdrrec_getint32 (xdrs, &v);
 235   *lp = v;
 236   return r;
 237 }
 238 #endif
 239
 240 static bool_t
 241 xdrrec_putint32 (XDR *xdrs, const int32_t *ip)
 242 {
 243   RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
 244   int32_t *dest_ip = (int32_t *) rstrm->out_finger;
 245
 246   if ((rstrm->out_finger += BYTES_PER_XDR_UNIT) > rstrm->out_boundry)
 247     {
 248       /*
 249        * this case should almost never happen so the code is
 250        * inefficient
 251        */
 252       rstrm->out_finger -= BYTES_PER_XDR_UNIT;
 253       rstrm->frag_sent = TRUE;
 254       if (!flush_out (rstrm, FALSE))
 255         return FALSE;
 256       dest_ip = (int32_t *) rstrm->out_finger;
 257       rstrm->out_finger += BYTES_PER_XDR_UNIT;
 258     }
 259   *dest_ip = htonl (*ip);
 260   return TRUE;
 261 }
 262
 263 #if ULONG_MAX != 0xffffffff
 264 static bool_t
 265 xdrrec_putlong (XDR *xdrs, const long *lp)
 266 {
 267   int32_t v = *lp;
 268   return xdrrec_putint32 (xdrs, &v);
 269 }
 270 #endif
 271
 272 static bool_t      /* must manage buffers, fragments, and records */
 273 xdrrec_getbytes (XDR *xdrs, caddr_t addr, u_int len)
 274 {
 275   RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
 276   u_int current;
 277
 278   while (len > 0)
 279     {
 280       current = rstrm->fbtbc;
 281       if (current == 0)
 282         {
 283           if (rstrm->last_frag)
 284             return FALSE;
 285           if (!set_input_fragment (rstrm))
 286             return FALSE;
 287           continue;
 288         }
 289       current = (len < current) ? len : current;
 290       if (!get_input_bytes (rstrm, addr, current))
 291         return FALSE;
 292       addr += current;
 293       rstrm->fbtbc -= current;
 294       len -= current;
 295     }
 296   return TRUE;
 297 }
 298
 299 static bool_t
 300 xdrrec_putbytes (XDR *xdrs, const char *addr, u_int len)
 301 {
 302   RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
 303   u_int current;
 304
 305   while (len > 0)
 306     {
 307       current = rstrm->out_boundry - rstrm->out_finger;
 308       current = (len < current) ? len : current;
 309       memcpy (rstrm->out_finger, addr, current);
 310       rstrm->out_finger += current;
 311       addr += current;
 312       len -= current;
 313       if (rstrm->out_finger == rstrm->out_boundry && len > 0)
 314         {
 315           rstrm->frag_sent = TRUE;
 316           if (!flush_out (rstrm, FALSE))
 317             return FALSE;
 318         }
 319     }
 320   return TRUE;
 321 }
 322
 323 static u_int
 324 xdrrec_getpos (const XDR *xdrs)
 325 {
 326   RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
 327   long pos;
 328
 329   pos = lseek ((int) (long) rstrm->tcp_handle, (long) 0, 1);
 330   if (pos != -1)
 331     switch (xdrs->x_op)
 332       {
 333
 334       case XDR_ENCODE:
 335         pos += rstrm->out_finger - rstrm->out_base;
 336         break;
 337
 338       case XDR_DECODE:
 339         pos -= rstrm->in_boundry - rstrm->in_finger;
 340         break;
 341
 342       default:
 343         pos = (u_int) - 1;
 344         break;
 345       }
 346   return (u_int) pos;
 347 }
 348
 349 static bool_t
 350 xdrrec_setpos (XDR *xdrs, u_int pos)
 351 {
 352   RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
 353   u_int currpos = xdrrec_getpos (xdrs);
 354   int delta = currpos - pos;
 355   caddr_t newpos;
 356
 357   if ((int) currpos != -1)
 358     switch (xdrs->x_op)
 359       {
 360
 361       case XDR_ENCODE:
 362         newpos = rstrm->out_finger - delta;
 363         if (newpos > (caddr_t) rstrm->frag_header &&
 364             newpos < rstrm->out_boundry)
 365           {
 366             rstrm->out_finger = newpos;
 367             return TRUE;
 368           }
 369         break;
 370
 371       case XDR_DECODE:
 372         newpos = rstrm->in_finger - delta;
 373         if ((delta < (int) (rstrm->fbtbc)) &&
 374             (newpos <= rstrm->in_boundry) &&
 375             (newpos >= rstrm->in_base))
 376           {
 377             rstrm->in_finger = newpos;
 378             rstrm->fbtbc -= delta;
 379             return TRUE;
 380           }
 381         break;
 382
 383       default:
 384         break;
 385       }
 386   return FALSE;
 387 }
 388
 389 static int32_t *
 390 xdrrec_inline (XDR *xdrs, u_int len)
 391 {
 392   RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
 393   int32_t *buf = NULL;
 394
 395   switch (xdrs->x_op)
 396     {
 397
 398     case XDR_ENCODE:
 399       if ((rstrm->out_finger + len) <= rstrm->out_boundry)
 400         {
 401           buf = (int32_t *) rstrm->out_finger;
 402           rstrm->out_finger += len;
 403         }
 404       break;
 405
 406     case XDR_DECODE:
 407       if ((len <= rstrm->fbtbc) &&
 408           ((rstrm->in_finger + len) <= rstrm->in_boundry))
 409         {
 410           buf = (int32_t *) rstrm->in_finger;
 411           rstrm->fbtbc -= len;
 412           rstrm->in_finger += len;
 413         }
 414       break;
 415
 416     default:
 417       break;
 418     }
 419   return buf;
 420 }
 421
 422 static void
 423 xdrrec_destroy (XDR *xdrs)
 424 {
 425   RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
 426
 427   mem_free (rstrm->the_buffer,
 428             rstrm->sendsize + rstrm->recvsize + BYTES_PER_XDR_UNIT);
 429   mem_free ((caddr_t) rstrm, sizeof (RECSTREAM));
 430 }
 431
 432 /*
 433  * Exported routines to manage xdr records
 434  */
 435
 436 /*
 437  * Before reading (deserializing from the stream, one should always call
 438  * this procedure to guarantee proper record alignment.
 439  */
 440 bool_t
 441 xdrrec_skiprecord (XDR *xdrs)
 442 {
 443   RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
 444
 445   while (rstrm->fbtbc > 0 || (!rstrm->last_frag))
 446     {
 447       if (!skip_input_bytes (rstrm, rstrm->fbtbc))
 448         return FALSE;
 449       rstrm->fbtbc = 0;
 450       if ((!rstrm->last_frag) && (!set_input_fragment (rstrm)))
 451         return FALSE;
 452     }
 453   rstrm->last_frag = FALSE;
 454   return TRUE;
 455 }
 456 libc_hidden_def(xdrrec_skiprecord)
 457
 458 /*
 459  * Lookahead function.
 460  * Returns TRUE iff there is no more input in the buffer
 461  * after consuming the rest of the current record.
 462  */
 463 bool_t
 464 xdrrec_eof (XDR *xdrs)
 465 {
 466   RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
 467
 468   while (rstrm->fbtbc > 0 || (!rstrm->last_frag))
 469     {
 470       if (!skip_input_bytes (rstrm, rstrm->fbtbc))
 471         return TRUE;
 472       rstrm->fbtbc = 0;
 473       if ((!rstrm->last_frag) && (!set_input_fragment (rstrm)))
 474         return TRUE;
 475     }
 476   if (rstrm->in_finger == rstrm->in_boundry)
 477     return TRUE;
 478   return FALSE;
 479 }
 480 libc_hidden_def(xdrrec_eof)
 481
 482 /*
 483  * The client must tell the package when an end-of-record has occurred.
 484  * The second parameter tells whether the record should be flushed to the
 485  * (output) tcp stream.  (This lets the package support batched or
 486  * pipelined procedure calls.)  TRUE => immediate flush to tcp connection.
 487  */
 488 bool_t
 489 xdrrec_endofrecord (XDR *xdrs, bool_t sendnow)
 490 {
 491   RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
 492   u_long len;           /* fragment length */
 493
 494   if (sendnow || rstrm->frag_sent
 495       || rstrm->out_finger + BYTES_PER_XDR_UNIT >= rstrm->out_boundry)
 496     {
 497       rstrm->frag_sent = FALSE;
 498       return flush_out (rstrm, TRUE);
 499     }
 500   len = (rstrm->out_finger - (char *) rstrm->frag_header
 501          - BYTES_PER_XDR_UNIT);
 502   *rstrm->frag_header = htonl ((u_long) len | LAST_FRAG);
 503   rstrm->frag_header = (u_int32_t *) rstrm->out_finger;
 504   rstrm->out_finger += BYTES_PER_XDR_UNIT;
 505   return TRUE;
 506 }
 507 libc_hidden_def(xdrrec_endofrecord)
 508
 509 /*
 510  * Internal useful routines
 511  */
 512 static bool_t
 513 internal_function
 514 flush_out (RECSTREAM *rstrm, bool_t eor)
 515 {
 516   u_long eormask = (eor == TRUE) ? LAST_FRAG : 0;
 517   u_long len = (rstrm->out_finger - (char *) rstrm->frag_header
 518                 - BYTES_PER_XDR_UNIT);
 519
 520   *rstrm->frag_header = htonl (len | eormask);
 521   len = rstrm->out_finger - rstrm->out_base;
 522   if ((*(rstrm->writeit)) (rstrm->tcp_handle, rstrm->out_base, (int) len)
 523       != (int) len)
 524     return FALSE;
 525   rstrm->frag_header = (u_int32_t *) rstrm->out_base;
 526   rstrm->out_finger = (caddr_t) rstrm->out_base + BYTES_PER_XDR_UNIT;
 527   return TRUE;
 528 }
 529
 530 static bool_t   /* knows nothing about records!  Only about input buffers */
 531 fill_input_buf (RECSTREAM *rstrm)
 532 {
 533   caddr_t where;
 534   size_t i;
 535   int len;
 536
 537   where = rstrm->in_base;
 538   i = (size_t) rstrm->in_boundry % BYTES_PER_XDR_UNIT;
 539   where += i;
 540   len = rstrm->in_size - i;
 541   if ((len = (*(rstrm->readit)) (rstrm->tcp_handle, where, len)) == -1)
 542     return FALSE;
 543   rstrm->in_finger = where;
 544   where += len;
 545   rstrm->in_boundry = where;
 546   return TRUE;
 547 }
 548
 549 static bool_t   /* knows nothing about records!  Only about input buffers */
 550 internal_function
 551 get_input_bytes (RECSTREAM *rstrm, caddr_t addr, int len)
 552 {
 553   int current;
 554
 555   while (len > 0)
 556     {
 557       current = rstrm->in_boundry - rstrm->in_finger;
 558       if (current == 0)
 559         {
 560           if (!fill_input_buf (rstrm))
 561             return FALSE;
 562           continue;
 563         }
 564       current = (len < current) ? len : current;
 565       memcpy (addr, rstrm->in_finger, current);
 566       rstrm->in_finger += current;
 567       addr += current;
 568       len -= current;
 569     }
 570   return TRUE;
 571 }
 572
 573 static bool_t /* next two bytes of the input stream are treated as a header */
 574 internal_function
 575 set_input_fragment (RECSTREAM *rstrm)
 576 {
 577   uint32_t header;
 578
 579   if (! get_input_bytes (rstrm, (caddr_t)&header, BYTES_PER_XDR_UNIT))
 580     return FALSE;
 581   header = ntohl (header);
 582   rstrm->last_frag = ((header & LAST_FRAG) == 0) ? FALSE : TRUE;
 583   /*
 584    * Sanity check. Try not to accept wildly incorrect fragment
 585    * sizes. Unfortunately, only a size of zero can be identified as
 586    * 'wildely incorrect', and this only, if it is not the last
 587    * fragment of a message. Ridiculously large fragment sizes may look
 588    * wrong, but we don't have any way to be certain that they aren't
 589    * what the client actually intended to send us. Many existing RPC
 590    * implementations may sent a fragment of size zero as the last
 591    * fragment of a message.
 592    */
 593   if (header == 0)
 594     return FALSE;
 595   rstrm->fbtbc = header & ~LAST_FRAG;
 596   return TRUE;
 597 }
 598
 599 static bool_t   /* consumes input bytes; knows nothing about records! */
 600 internal_function
 601 skip_input_bytes (RECSTREAM *rstrm, long cnt)
 602 {
 603   int current;
 604
 605   while (cnt > 0)
 606     {
 607       current = rstrm->in_boundry - rstrm->in_finger;
 608       if (current == 0)
 609         {
 610           if (!fill_input_buf (rstrm))
 611             return FALSE;
 612           continue;
 613         }
 614       current = (cnt < current) ? cnt : current;
 615       rstrm->in_finger += current;
 616       cnt -= current;
 617     }
 618   return TRUE;
 619 }
 620
 621 static u_int
 622 internal_function
 623 fix_buf_size (u_int s)
 624 {
 625   if (s < 100)
 626     s = 4000;
 627   return RNDUP (s);
 628 }