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
  52 #ifdef USE_IN_LIBIO
  53 # include <libio/iolibio.h>
  54 # define fputs(s, f) _IO_fputs (s, f)
  55 #endif
  56
  57 static bool_t xdrrec_getlong (XDR *, long *);
  58 static bool_t xdrrec_putlong (XDR *, const long *);
  59 static bool_t xdrrec_getbytes (XDR *, caddr_t, u_int);
  60 static bool_t xdrrec_putbytes (XDR *, const char *, u_int);
  61 static u_int xdrrec_getpos (const XDR *);
  62 static bool_t xdrrec_setpos (XDR *, u_int);
  63 static int32_t *xdrrec_inline (XDR *, int);
  64 static void xdrrec_destroy (XDR *);
  65 static bool_t xdrrec_getint32 (XDR *, int32_t *);
  66 static bool_t xdrrec_putint32 (XDR *, const int32_t *);
  67
  68 static const struct xdr_ops xdrrec_ops =
  69 {
  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
 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 (XDR *xdrs, long *lp)
 204 {
 205   RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
 206   int32_t *buflp = (int32_t *) rstrm->in_finger;
 207   int32_t mylong;
 208
 209   /* first try the inline, fast case */
 210   if (rstrm->fbtbc >= BYTES_PER_XDR_UNIT &&
 211       rstrm->in_boundry - (char *) buflp >= BYTES_PER_XDR_UNIT)
 212     {
 213       *lp = (int32_t) ntohl (*buflp);
 214       rstrm->fbtbc -= BYTES_PER_XDR_UNIT;
 215       rstrm->in_finger += BYTES_PER_XDR_UNIT;
 216     }
 217   else
 218     {
 219       if (!xdrrec_getbytes (xdrs, (caddr_t) & mylong,
 220                             BYTES_PER_XDR_UNIT))
 221         return FALSE;
 222       *lp = (int32_t) ntohl (mylong);
 223     }
 224   return TRUE;
 225 }
 226
 227 static bool_t
 228 xdrrec_putlong (XDR *xdrs, const long *lp)
 229 {
 230   RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
 231   int32_t *dest_lp = (int32_t *) rstrm->out_finger;
 232
 233   if ((rstrm->out_finger += BYTES_PER_XDR_UNIT) > rstrm->out_boundry)
 234     {
 235       /*
 236        * this case should almost never happen so the code is
 237        * inefficient
 238        */
 239       rstrm->out_finger -= BYTES_PER_XDR_UNIT;
 240       rstrm->frag_sent = TRUE;
 241       if (!flush_out (rstrm, FALSE))
 242         return FALSE;
 243       dest_lp = (int32_t *) rstrm->out_finger;
 244       rstrm->out_finger += BYTES_PER_XDR_UNIT;
 245     }
 246   *dest_lp = htonl (*lp);
 247   return TRUE;
 248 }
 249
 250 static bool_t      /* must manage buffers, fragments, and records */
 251 xdrrec_getbytes (XDR *xdrs, caddr_t addr, 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 (XDR *xdrs, const char *addr, u_int len)
 279 {
 280   RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
 281   u_int current;
 282
 283   while (len > 0)
 284     {
 285       current = rstrm->out_boundry - rstrm->out_finger;
 286       current = (len < current) ? len : current;
 287       bcopy (addr, rstrm->out_finger, current);
 288       rstrm->out_finger += current;
 289       addr += current;
 290       len -= current;
 291       if (rstrm->out_finger == rstrm->out_boundry)
 292         {
 293           rstrm->frag_sent = TRUE;
 294           if (!flush_out (rstrm, FALSE))
 295             return FALSE;
 296         }
 297     }
 298   return TRUE;
 299 }
 300
 301 static u_int
 302 xdrrec_getpos (const XDR *xdrs)
 303 {
 304   RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
 305   long pos;
 306
 307   pos = __lseek ((int) rstrm->tcp_handle, (long) 0, 1);
 308   if (pos != -1)
 309     switch (xdrs->x_op)
 310       {
 311
 312       case XDR_ENCODE:
 313         pos += rstrm->out_finger - rstrm->out_base;
 314         break;
 315
 316       case XDR_DECODE:
 317         pos -= rstrm->in_boundry - rstrm->in_finger;
 318         break;
 319
 320       default:
 321         pos = (u_int) - 1;
 322         break;
 323       }
 324   return (u_int) pos;
 325 }
 326
 327 static bool_t
 328 xdrrec_setpos (XDR *xdrs, u_int pos)
 329 {
 330   RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
 331   u_int currpos = xdrrec_getpos (xdrs);
 332   int delta = currpos - pos;
 333   caddr_t newpos;
 334
 335   if ((int) currpos != -1)
 336     switch (xdrs->x_op)
 337       {
 338
 339       case XDR_ENCODE:
 340         newpos = rstrm->out_finger - delta;
 341         if (newpos > (caddr_t) rstrm->frag_header &&
 342             newpos < rstrm->out_boundry)
 343           {
 344             rstrm->out_finger = newpos;
 345             return TRUE;
 346           }
 347         break;
 348
 349       case XDR_DECODE:
 350         newpos = rstrm->in_finger - delta;
 351         if ((delta < (int) (rstrm->fbtbc)) &&
 352             (newpos <= rstrm->in_boundry) &&
 353             (newpos >= rstrm->in_base))
 354           {
 355             rstrm->in_finger = newpos;
 356             rstrm->fbtbc -= delta;
 357             return TRUE;
 358           }
 359         break;
 360
 361       default:
 362         break;
 363       }
 364   return FALSE;
 365 }
 366
 367 static int32_t *
 368 xdrrec_inline (XDR *xdrs, int len)
 369 {
 370   RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
 371   int32_t *buf = NULL;
 372
 373   switch (xdrs->x_op)
 374     {
 375
 376     case XDR_ENCODE:
 377       if ((rstrm->out_finger + len) <= rstrm->out_boundry)
 378         {
 379           buf = (int32_t *) rstrm->out_finger;
 380           rstrm->out_finger += len;
 381         }
 382       break;
 383
 384     case XDR_DECODE:
 385       if ((len <= rstrm->fbtbc) &&
 386           ((rstrm->in_finger + len) <= rstrm->in_boundry))
 387         {
 388           buf = (int32_t *) rstrm->in_finger;
 389           rstrm->fbtbc -= len;
 390           rstrm->in_finger += len;
 391         }
 392       break;
 393
 394     default:
 395       break;
 396     }
 397   return buf;
 398 }
 399
 400 static void
 401 xdrrec_destroy (XDR *xdrs)
 402 {
 403   RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
 404
 405   mem_free (rstrm->the_buffer,
 406             rstrm->sendsize + rstrm->recvsize + BYTES_PER_XDR_UNIT);
 407   mem_free ((caddr_t) rstrm, sizeof (RECSTREAM));
 408 }
 409
 410 static bool_t
 411 xdrrec_getint32 (XDR *xdrs, int32_t *ip)
 412 {
 413   RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
 414   int32_t *bufip = (int32_t *) rstrm->in_finger;
 415   int32_t mylong;
 416
 417   /* first try the inline, fast case */
 418   if (rstrm->fbtbc >= BYTES_PER_XDR_UNIT &&
 419       rstrm->in_boundry - (char *) bufip >= BYTES_PER_XDR_UNIT)
 420     {
 421       *ip = ntohl (*bufip);
 422       rstrm->fbtbc -= BYTES_PER_XDR_UNIT;
 423       rstrm->in_finger += BYTES_PER_XDR_UNIT;
 424     }
 425   else
 426     {
 427       if (!xdrrec_getbytes (xdrs, (caddr_t) &mylong,
 428                             BYTES_PER_XDR_UNIT))
 429         return FALSE;
 430       *ip = ntohl (mylong);
 431     }
 432   return TRUE;
 433 }
 434
 435 static bool_t
 436 xdrrec_putint32 (XDR *xdrs, const int32_t *ip)
 437 {
 438   RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
 439   int32_t *dest_ip = (int32_t *) rstrm->out_finger;
 440
 441   if ((rstrm->out_finger += BYTES_PER_XDR_UNIT) > rstrm->out_boundry)
 442     {
 443       /*
 444        * this case should almost never happen so the code is
 445        * inefficient
 446        */
 447       rstrm->out_finger -= BYTES_PER_XDR_UNIT;
 448       rstrm->frag_sent = TRUE;
 449       if (!flush_out (rstrm, FALSE))
 450         return FALSE;
 451       dest_ip = (int32_t *) rstrm->out_finger;
 452       rstrm->out_finger += BYTES_PER_XDR_UNIT;
 453     }
 454   *dest_ip = htonl (*ip);
 455   return TRUE;
 456 }
 457
 458 /*
 459  * Exported routines to manage xdr records
 460  */
 461
 462 /*
 463  * Before reading (deserializing from the stream, one should always call
 464  * this procedure to guarantee proper record alignment.
 465  */
 466 bool_t
 467 xdrrec_skiprecord (xdrs)
 468      XDR *xdrs;
 469 {
 470   RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
 471
 472   while (rstrm->fbtbc > 0 || (!rstrm->last_frag))
 473     {
 474       if (!skip_input_bytes (rstrm, rstrm->fbtbc))
 475         return FALSE;
 476       rstrm->fbtbc = 0;
 477       if ((!rstrm->last_frag) && (!set_input_fragment (rstrm)))
 478         return FALSE;
 479     }
 480   rstrm->last_frag = FALSE;
 481   return TRUE;
 482 }
 483
 484 /*
 485  * Lookahead function.
 486  * Returns TRUE iff there is no more input in the buffer
 487  * after consuming the rest of the current record.
 488  */
 489 bool_t
 490 xdrrec_eof (xdrs)
 491      XDR *xdrs;
 492 {
 493   RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
 494
 495   while (rstrm->fbtbc > 0 || (!rstrm->last_frag))
 496     {
 497       if (!skip_input_bytes (rstrm, rstrm->fbtbc))
 498         return TRUE;
 499       rstrm->fbtbc = 0;
 500       if ((!rstrm->last_frag) && (!set_input_fragment (rstrm)))
 501         return TRUE;
 502     }
 503   if (rstrm->in_finger == rstrm->in_boundry)
 504     return TRUE;
 505   return FALSE;
 506 }
 507
 508 /*
 509  * The client must tell the package when an end-of-record has occurred.
 510  * The second parameter tells whether the record should be flushed to the
 511  * (output) tcp stream.  (This lets the package support batched or
 512  * pipelined procedure calls.)  TRUE => immediate flush to tcp connection.
 513  */
 514 bool_t
 515 xdrrec_endofrecord (xdrs, sendnow)
 516      XDR *xdrs;
 517      bool_t sendnow;
 518 {
 519   RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
 520   u_long len;           /* fragment length */
 521
 522   if (sendnow || rstrm->frag_sent
 523       || rstrm->out_finger + BYTES_PER_XDR_UNIT >= rstrm->out_boundry)
 524     {
 525       rstrm->frag_sent = FALSE;
 526       return flush_out (rstrm, TRUE);
 527     }
 528   len = (rstrm->out_finger - (char *) rstrm->frag_header
 529          - BYTES_PER_XDR_UNIT);
 530   *rstrm->frag_header = htonl ((u_long) len | LAST_FRAG);
 531   rstrm->frag_header = (u_int32_t *) rstrm->out_finger;
 532   rstrm->out_finger += BYTES_PER_XDR_UNIT;
 533   return TRUE;
 534 }
 535
 536
 537 /*
 538  * Internal useful routines
 539  */
 540 static bool_t
 541 internal_function
 542 flush_out (RECSTREAM *rstrm, bool_t eor)
 543 {
 544   u_long eormask = (eor == TRUE) ? LAST_FRAG : 0;
 545   u_long len = (rstrm->out_finger - (char *) rstrm->frag_header
 546                 - BYTES_PER_XDR_UNIT);
 547
 548   *rstrm->frag_header = htonl (len | eormask);
 549   len = rstrm->out_finger - rstrm->out_base;
 550   if ((*(rstrm->writeit)) (rstrm->tcp_handle, rstrm->out_base, (int) len)
 551       != (int) len)
 552     return FALSE;
 553   rstrm->frag_header = (u_int32_t *) rstrm->out_base;
 554   rstrm->out_finger = (caddr_t) rstrm->out_base + BYTES_PER_XDR_UNIT;
 555   return TRUE;
 556 }
 557
 558 static bool_t   /* knows nothing about records!  Only about input buffers */
 559 fill_input_buf (RECSTREAM *rstrm)
 560 {
 561   caddr_t where;
 562   size_t i;
 563   int len;
 564
 565   where = rstrm->in_base;
 566   i = (size_t) rstrm->in_boundry % BYTES_PER_XDR_UNIT;
 567   where += i;
 568   len = rstrm->in_size - i;
 569   if ((len = (*(rstrm->readit)) (rstrm->tcp_handle, where, len)) == -1)
 570     return FALSE;
 571   rstrm->in_finger = where;
 572   where += len;
 573   rstrm->in_boundry = where;
 574   return TRUE;
 575 }
 576
 577 static bool_t   /* knows nothing about records!  Only about input buffers */
 578 internal_function
 579 get_input_bytes (RECSTREAM *rstrm, caddr_t addr, int len)
 580 {
 581   int current;
 582
 583   while (len > 0)
 584     {
 585       current = rstrm->in_boundry - rstrm->in_finger;
 586       if (current == 0)
 587         {
 588           if (!fill_input_buf (rstrm))
 589             return FALSE;
 590           continue;
 591         }
 592       current = (len < current) ? len : current;
 593       bcopy (rstrm->in_finger, addr, current);
 594       rstrm->in_finger += current;
 595       addr += current;
 596       len -= current;
 597     }
 598   return TRUE;
 599 }
 600
 601 static bool_t /* next two bytes of the input stream are treated as a header */
 602 internal_function
 603 set_input_fragment (RECSTREAM *rstrm)
 604 {
 605   u_long header;
 606
 607   if (! get_input_bytes (rstrm, (caddr_t)&header, BYTES_PER_XDR_UNIT))
 608     return FALSE;
 609   header = ntohl (header);
 610   rstrm->last_frag = ((header & LAST_FRAG) == 0) ? FALSE : TRUE;
 611   /*
 612    * Sanity check. Try not to accept wildly incorrect
 613    * record sizes. Unfortunately, the only record size
 614    * we can positively identify as being 'wildly incorrect'
 615    * is zero.  Ridiculously large record sizes may look wrong,
 616    * but we don't have any way to be certain that they aren't
 617    * what the client actually intended to send us.
 618    */
 619   if ((header & (~LAST_FRAG)) == 0)
 620     return FALSE;
 621   rstrm->fbtbc = header & ~LAST_FRAG;
 622   return TRUE;
 623 }
 624
 625 static bool_t   /* consumes input bytes; knows nothing about records! */
 626 internal_function
 627 skip_input_bytes (RECSTREAM *rstrm, long cnt)
 628 {
 629   int current;
 630
 631   while (cnt > 0)
 632     {
 633       current = rstrm->in_boundry - rstrm->in_finger;
 634       if (current == 0)
 635         {
 636           if (!fill_input_buf (rstrm))
 637             return FALSE;
 638           continue;
 639         }
 640       current = (cnt < current) ? cnt : current;
 641       rstrm->in_finger += current;
 642       cnt -= current;
 643     }
 644   return TRUE;
 645 }
 646
 647 static u_int
 648 internal_function
 649 fix_buf_size (u_int s)
 650 {
 651   if (s < 100)
 652     s = 4000;
 653   return RNDUP (s);
 654 }