sunrpc/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/rpc.h>
  51 #include <libintl.h>
  52
  53 #ifdef USE_IN_LIBIO
  54 # include <wchar.h>
  55 # include <libio/iolibio.h>
  56 #endif
  57
  58 static bool_t xdrrec_getlong (XDR *, long *);
  59 static bool_t xdrrec_putlong (XDR *, const long *);
  60 static bool_t xdrrec_getbytes (XDR *, caddr_t, u_int);
  61 static bool_t xdrrec_putbytes (XDR *, const char *, u_int);
  62 static u_int xdrrec_getpos (const XDR *);
  63 static bool_t xdrrec_setpos (XDR *, u_int);
  64 static int32_t *xdrrec_inline (XDR *, u_int);
  65 static void xdrrec_destroy (XDR *);
  66 static bool_t xdrrec_getint32 (XDR *, int32_t *);
  67 static bool_t xdrrec_putint32 (XDR *, const int32_t *);
  68
  69 static const struct xdr_ops xdrrec_ops = {
  70   xdrrec_getlong,
  71   xdrrec_putlong,
  72   xdrrec_getbytes,
  73   xdrrec_putbytes,
  74   xdrrec_getpos,
  75   xdrrec_setpos,
  76   xdrrec_inline,
  77   xdrrec_destroy,
  78   xdrrec_getint32,
  79   xdrrec_putint32
  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   char *buf;
 149
 150   sendsize = fix_buf_size (sendsize);
 151   recvsize = fix_buf_size (recvsize);
 152   buf = mem_alloc (sendsize + recvsize + BYTES_PER_XDR_UNIT);
 153
 154   if (rstrm == NULL || buf == NULL)
 155     {
 156       (void) __fxprintf (NULL, "%s: %s", __func__, _("out of memory\n"));
 157       mem_free (rstrm, sizeof (RECSTREAM));
 158       mem_free (buf, sendsize + recvsize + BYTES_PER_XDR_UNIT);
 159       /*
 160        *  This is bad.  Should rework xdrrec_create to
 161        *  return a handle, and in this case return NULL
 162        */
 163       return;
 164     }
 165   /*
 166    * adjust sizes and allocate buffer quad byte aligned
 167    */
 168   rstrm->sendsize = sendsize;
 169   rstrm->recvsize = recvsize;
 170   rstrm->the_buffer = buf;
 171   tmp = rstrm->the_buffer;
 172   if ((size_t)tmp % BYTES_PER_XDR_UNIT)
 173     tmp += BYTES_PER_XDR_UNIT - (size_t)tmp % BYTES_PER_XDR_UNIT;
 174   rstrm->out_base = tmp;
 175   rstrm->in_base = tmp + sendsize;
 176   /*
 177    * now the rest ...
 178    */
 179   /* We have to add the cast since the `struct xdr_ops' in `struct XDR'
 180      is not `const'.  */
 181   xdrs->x_ops = (struct xdr_ops *) &xdrrec_ops;
 182   xdrs->x_private = (caddr_t) rstrm;
 183   rstrm->tcp_handle = tcp_handle;
 184   rstrm->readit = readit;
 185   rstrm->writeit = writeit;
 186   rstrm->out_finger = rstrm->out_boundry = rstrm->out_base;
 187   rstrm->frag_header = (u_int32_t *) rstrm->out_base;
 188   rstrm->out_finger += 4;
 189   rstrm->out_boundry += sendsize;
 190   rstrm->frag_sent = FALSE;
 191   rstrm->in_size = recvsize;
 192   rstrm->in_boundry = rstrm->in_base;
 193   rstrm->in_finger = (rstrm->in_boundry += recvsize);
 194   rstrm->fbtbc = 0;
 195   rstrm->last_frag = TRUE;
 196 }
 197 INTDEF(xdrrec_create)
 198
 199
 200 /*
 201  * The routines defined below are the xdr ops which will go into the
 202  * xdr handle filled in by xdrrec_create.
 203  */
 204
 205 static bool_t
 206 xdrrec_getlong (XDR *xdrs, long *lp)
 207 {
 208   RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
 209   int32_t *buflp = (int32_t *) rstrm->in_finger;
 210   int32_t mylong;
 211
 212   /* first try the inline, fast case */
 213   if (rstrm->fbtbc >= BYTES_PER_XDR_UNIT &&
 214       rstrm->in_boundry - (char *) buflp >= BYTES_PER_XDR_UNIT)
 215     {
 216       *lp = (int32_t) ntohl (*buflp);
 217       rstrm->fbtbc -= BYTES_PER_XDR_UNIT;
 218       rstrm->in_finger += BYTES_PER_XDR_UNIT;
 219     }
 220   else
 221     {
 222       if (!xdrrec_getbytes (xdrs, (caddr_t) & mylong,
 223                             BYTES_PER_XDR_UNIT))
 224         return FALSE;
 225       *lp = (int32_t) ntohl (mylong);
 226     }
 227   return TRUE;
 228 }
 229
 230 static bool_t
 231 xdrrec_putlong (XDR *xdrs, const long *lp)
 232 {
 233   RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
 234   int32_t *dest_lp = (int32_t *) rstrm->out_finger;
 235
 236   if ((rstrm->out_finger += BYTES_PER_XDR_UNIT) > rstrm->out_boundry)
 237     {
 238       /*
 239        * this case should almost never happen so the code is
 240        * inefficient
 241        */
 242       rstrm->out_finger -= BYTES_PER_XDR_UNIT;
 243       rstrm->frag_sent = TRUE;
 244       if (!flush_out (rstrm, FALSE))
 245         return FALSE;
 246       dest_lp = (int32_t *) rstrm->out_finger;
 247       rstrm->out_finger += BYTES_PER_XDR_UNIT;
 248     }
 249   *dest_lp = htonl (*lp);
 250   return TRUE;
 251 }
 252
 253 static bool_t      /* must manage buffers, fragments, and records */
 254 xdrrec_getbytes (XDR *xdrs, caddr_t addr, u_int len)
 255 {
 256   RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
 257   u_int current;
 258
 259   while (len > 0)
 260     {
 261       current = rstrm->fbtbc;
 262       if (current == 0)
 263         {
 264           if (rstrm->last_frag)
 265             return FALSE;
 266           if (!set_input_fragment (rstrm))
 267             return FALSE;
 268           continue;
 269         }
 270       current = (len < current) ? len : current;
 271       if (!get_input_bytes (rstrm, addr, current))
 272         return FALSE;
 273       addr += current;
 274       rstrm->fbtbc -= current;
 275       len -= current;
 276     }
 277   return TRUE;
 278 }
 279
 280 static bool_t
 281 xdrrec_putbytes (XDR *xdrs, const char *addr, 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       memcpy (rstrm->out_finger, addr, current);
 291       rstrm->out_finger += current;
 292       addr += current;
 293       len -= current;
 294       if (rstrm->out_finger == rstrm->out_boundry && len > 0)
 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) (long) 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 (XDR *xdrs, u_int pos)
 332 {
 333   RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
 334   u_int currpos = xdrrec_getpos (xdrs);
 335   int delta = currpos - pos;
 336   caddr_t newpos;
 337
 338   if ((int) currpos != -1)
 339     switch (xdrs->x_op)
 340       {
 341
 342       case XDR_ENCODE:
 343         newpos = rstrm->out_finger - delta;
 344         if (newpos > (caddr_t) rstrm->frag_header &&
 345             newpos < rstrm->out_boundry)
 346           {
 347             rstrm->out_finger = newpos;
 348             return TRUE;
 349           }
 350         break;
 351
 352       case XDR_DECODE:
 353         newpos = rstrm->in_finger - delta;
 354         if ((delta < (int) (rstrm->fbtbc)) &&
 355             (newpos <= rstrm->in_boundry) &&
 356             (newpos >= rstrm->in_base))
 357           {
 358             rstrm->in_finger = newpos;
 359             rstrm->fbtbc -= delta;
 360             return TRUE;
 361           }
 362         break;
 363
 364       default:
 365         break;
 366       }
 367   return FALSE;
 368 }
 369
 370 static int32_t *
 371 xdrrec_inline (XDR *xdrs, u_int len)
 372 {
 373   RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
 374   int32_t *buf = NULL;
 375
 376   switch (xdrs->x_op)
 377     {
 378
 379     case XDR_ENCODE:
 380       if ((rstrm->out_finger + len) <= rstrm->out_boundry)
 381         {
 382           buf = (int32_t *) rstrm->out_finger;
 383           rstrm->out_finger += len;
 384         }
 385       break;
 386
 387     case XDR_DECODE:
 388       if ((len <= rstrm->fbtbc) &&
 389           ((rstrm->in_finger + len) <= rstrm->in_boundry))
 390         {
 391           buf = (int32_t *) rstrm->in_finger;
 392           rstrm->fbtbc -= len;
 393           rstrm->in_finger += len;
 394         }
 395       break;
 396
 397     default:
 398       break;
 399     }
 400   return buf;
 401 }
 402
 403 static void
 404 xdrrec_destroy (XDR *xdrs)
 405 {
 406   RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
 407
 408   mem_free (rstrm->the_buffer,
 409             rstrm->sendsize + rstrm->recvsize + BYTES_PER_XDR_UNIT);
 410   mem_free ((caddr_t) rstrm, sizeof (RECSTREAM));
 411 }
 412
 413 static bool_t
 414 xdrrec_getint32 (XDR *xdrs, int32_t *ip)
 415 {
 416   RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
 417   int32_t *bufip = (int32_t *) rstrm->in_finger;
 418   int32_t mylong;
 419
 420   /* first try the inline, fast case */
 421   if (rstrm->fbtbc >= BYTES_PER_XDR_UNIT &&
 422       rstrm->in_boundry - (char *) bufip >= BYTES_PER_XDR_UNIT)
 423     {
 424       *ip = ntohl (*bufip);
 425       rstrm->fbtbc -= BYTES_PER_XDR_UNIT;
 426       rstrm->in_finger += BYTES_PER_XDR_UNIT;
 427     }
 428   else
 429     {
 430       if (!xdrrec_getbytes (xdrs, (caddr_t) &mylong,
 431                             BYTES_PER_XDR_UNIT))
 432         return FALSE;
 433       *ip = ntohl (mylong);
 434     }
 435   return TRUE;
 436 }
 437
 438 static bool_t
 439 xdrrec_putint32 (XDR *xdrs, const int32_t *ip)
 440 {
 441   RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
 442   int32_t *dest_ip = (int32_t *) rstrm->out_finger;
 443
 444   if ((rstrm->out_finger += BYTES_PER_XDR_UNIT) > rstrm->out_boundry)
 445     {
 446       /*
 447        * this case should almost never happen so the code is
 448        * inefficient
 449        */
 450       rstrm->out_finger -= BYTES_PER_XDR_UNIT;
 451       rstrm->frag_sent = TRUE;
 452       if (!flush_out (rstrm, FALSE))
 453         return FALSE;
 454       dest_ip = (int32_t *) rstrm->out_finger;
 455       rstrm->out_finger += BYTES_PER_XDR_UNIT;
 456     }
 457   *dest_ip = htonl (*ip);
 458   return TRUE;
 459 }
 460
 461 /*
 462  * Exported routines to manage xdr records
 463  */
 464
 465 /*
 466  * Before reading (deserializing from the stream, one should always call
 467  * this procedure to guarantee proper record alignment.
 468  */
 469 bool_t
 470 xdrrec_skiprecord (XDR *xdrs)
 471 {
 472   RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
 473
 474   while (rstrm->fbtbc > 0 || (!rstrm->last_frag))
 475     {
 476       if (!skip_input_bytes (rstrm, rstrm->fbtbc))
 477         return FALSE;
 478       rstrm->fbtbc = 0;
 479       if ((!rstrm->last_frag) && (!set_input_fragment (rstrm)))
 480         return FALSE;
 481     }
 482   rstrm->last_frag = FALSE;
 483   return TRUE;
 484 }
 485 INTDEF(xdrrec_skiprecord)
 486
 487 /*
 488  * Lookahead function.
 489  * Returns TRUE iff there is no more input in the buffer
 490  * after consuming the rest of the current record.
 491  */
 492 bool_t
 493 xdrrec_eof (XDR *xdrs)
 494 {
 495   RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
 496
 497   while (rstrm->fbtbc > 0 || (!rstrm->last_frag))
 498     {
 499       if (!skip_input_bytes (rstrm, rstrm->fbtbc))
 500         return TRUE;
 501       rstrm->fbtbc = 0;
 502       if ((!rstrm->last_frag) && (!set_input_fragment (rstrm)))
 503         return TRUE;
 504     }
 505   if (rstrm->in_finger == rstrm->in_boundry)
 506     return TRUE;
 507   return FALSE;
 508 }
 509 INTDEF(xdrrec_eof)
 510
 511 /*
 512  * The client must tell the package when an end-of-record has occurred.
 513  * The second parameter tells whether the record should be flushed to the
 514  * (output) tcp stream.  (This lets the package support batched or
 515  * pipelined procedure calls.)  TRUE => immediate flush to tcp connection.
 516  */
 517 bool_t
 518 xdrrec_endofrecord (XDR *xdrs, bool_t sendnow)
 519 {
 520   RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
 521   u_long len;           /* fragment length */
 522
 523   if (sendnow || rstrm->frag_sent
 524       || rstrm->out_finger + BYTES_PER_XDR_UNIT >= rstrm->out_boundry)
 525     {
 526       rstrm->frag_sent = FALSE;
 527       return flush_out (rstrm, TRUE);
 528     }
 529   len = (rstrm->out_finger - (char *) rstrm->frag_header
 530          - BYTES_PER_XDR_UNIT);
 531   *rstrm->frag_header = htonl ((u_long) len | LAST_FRAG);
 532   rstrm->frag_header = (u_int32_t *) rstrm->out_finger;
 533   rstrm->out_finger += BYTES_PER_XDR_UNIT;
 534   return TRUE;
 535 }
 536 INTDEF(xdrrec_endofrecord)
 537
 538
 539 /*
 540  * Internal useful routines
 541  */
 542 static bool_t
 543 internal_function
 544 flush_out (RECSTREAM *rstrm, bool_t eor)
 545 {
 546   u_long eormask = (eor == TRUE) ? LAST_FRAG : 0;
 547   u_long len = (rstrm->out_finger - (char *) rstrm->frag_header
 548                 - BYTES_PER_XDR_UNIT);
 549
 550   *rstrm->frag_header = htonl (len | eormask);
 551   len = rstrm->out_finger - rstrm->out_base;
 552   if ((*(rstrm->writeit)) (rstrm->tcp_handle, rstrm->out_base, (int) len)
 553       != (int) len)
 554     return FALSE;
 555   rstrm->frag_header = (u_int32_t *) rstrm->out_base;
 556   rstrm->out_finger = (caddr_t) rstrm->out_base + BYTES_PER_XDR_UNIT;
 557   return TRUE;
 558 }
 559
 560 static bool_t   /* knows nothing about records!  Only about input buffers */
 561 fill_input_buf (RECSTREAM *rstrm)
 562 {
 563   caddr_t where;
 564   size_t i;
 565   int len;
 566
 567   where = rstrm->in_base;
 568   i = (size_t) rstrm->in_boundry % BYTES_PER_XDR_UNIT;
 569   where += i;
 570   len = rstrm->in_size - i;
 571   if ((len = (*(rstrm->readit)) (rstrm->tcp_handle, where, len)) == -1)
 572     return FALSE;
 573   rstrm->in_finger = where;
 574   where += len;
 575   rstrm->in_boundry = where;
 576   return TRUE;
 577 }
 578
 579 static bool_t   /* knows nothing about records!  Only about input buffers */
 580 internal_function
 581 get_input_bytes (RECSTREAM *rstrm, caddr_t addr, int len)
 582 {
 583   int current;
 584
 585   while (len > 0)
 586     {
 587       current = rstrm->in_boundry - rstrm->in_finger;
 588       if (current == 0)
 589         {
 590           if (!fill_input_buf (rstrm))
 591             return FALSE;
 592           continue;
 593         }
 594       current = (len < current) ? len : current;
 595       memcpy (addr, rstrm->in_finger, current);
 596       rstrm->in_finger += current;
 597       addr += current;
 598       len -= current;
 599     }
 600   return TRUE;
 601 }
 602
 603 static bool_t /* next two bytes of the input stream are treated as a header */
 604 internal_function
 605 set_input_fragment (RECSTREAM *rstrm)
 606 {
 607   uint32_t header;
 608
 609   if (! get_input_bytes (rstrm, (caddr_t)&header, BYTES_PER_XDR_UNIT))
 610     return FALSE;
 611   header = ntohl (header);
 612   rstrm->last_frag = ((header & LAST_FRAG) == 0) ? FALSE : TRUE;
 613   /*
 614    * Sanity check. Try not to accept wildly incorrect fragment
 615    * sizes. Unfortunately, only a size of zero can be identified as
 616    * 'wildely incorrect', and this only, if it is not the last
 617    * fragment of a message. Ridiculously large fragment sizes may look
 618    * wrong, but we don't have any way to be certain that they aren't
 619    * what the client actually intended to send us. Many existing RPC
 620    * implementations may sent a fragment of size zero as the last
 621    * fragment of a message.
 622    */
 623   if (header == 0)
 624     return FALSE;
 625   rstrm->fbtbc = header & ~LAST_FRAG;
 626   return TRUE;
 627 }
 628
 629 static bool_t   /* consumes input bytes; knows nothing about records! */
 630 internal_function
 631 skip_input_bytes (RECSTREAM *rstrm, long cnt)
 632 {
 633   int current;
 634
 635   while (cnt > 0)
 636     {
 637       current = rstrm->in_boundry - rstrm->in_finger;
 638       if (current == 0)
 639         {
 640           if (!fill_input_buf (rstrm))
 641             return FALSE;
 642           continue;
 643         }
 644       current = (cnt < current) ? cnt : current;
 645       rstrm->in_finger += current;
 646       cnt -= current;
 647     }
 648   return TRUE;
 649 }
 650
 651 static u_int
 652 internal_function
 653 fix_buf_size (u_int s)
 654 {
 655   if (s < 100)
 656     s = 4000;
 657   return RNDUP (s);
 658 }