summaryrefslogtreecommitdiff
path: root/sunrpc/xdr_rec.c
blob: 9d79ace4b70f3a43d2ace2ef2e4929349f167832 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
/*
 * xdr_rec.c, Implements TCP/IP based XDR streams with a "record marking"
 * layer above tcp (for rpc's use).
 *
 * Copyright (c) 2010, Oracle America, Inc.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above
 *       copyright notice, this list of conditions and the following
 *       disclaimer in the documentation and/or other materials
 *       provided with the distribution.
 *     * Neither the name of the "Oracle America, Inc." nor the names of its
 *       contributors may be used to endorse or promote products derived
 *       from this software without specific prior written permission.
 *
 *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 *   FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 *   COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
 *   INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 *   DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
 *   GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 *   INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 *   WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 *   NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * These routines interface XDRSTREAMS to a tcp/ip connection.
 * There is a record marking layer between the xdr stream
 * and the tcp transport level.  A record is composed on one or more
 * record fragments.  A record fragment is a thirty-two bit header followed
 * by n bytes of data, where n is contained in the header.  The header
 * is represented as a htonl(u_long).  The high order bit encodes
 * whether or not the fragment is the last fragment of the record
 * (1 => fragment is last, 0 => more fragments to follow.
 * The other 31 bits encode the byte length of the fragment.
 */

#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <stdint.h>
#include <rpc/rpc.h>
#include <libintl.h>
#include <wchar.h>
#include <libio/iolibio.h>

static bool_t xdrrec_getlong (XDR *, long *);
static bool_t xdrrec_putlong (XDR *, const long *);
static bool_t xdrrec_getbytes (XDR *, caddr_t, u_int);
static bool_t xdrrec_putbytes (XDR *, const char *, u_int);
static u_int xdrrec_getpos (const XDR *);
static bool_t xdrrec_setpos (XDR *, u_int);
static int32_t *xdrrec_inline (XDR *, u_int);
static void xdrrec_destroy (XDR *);
static bool_t xdrrec_getint32 (XDR *, int32_t *);
static bool_t xdrrec_putint32 (XDR *, const int32_t *);

static const struct xdr_ops xdrrec_ops = {
  xdrrec_getlong,
  xdrrec_putlong,
  xdrrec_getbytes,
  xdrrec_putbytes,
  xdrrec_getpos,
  xdrrec_setpos,
  xdrrec_inline,
  xdrrec_destroy,
  xdrrec_getint32,
  xdrrec_putint32
};

/*
 * A record is composed of one or more record fragments.
 * A record fragment is a two-byte header followed by zero to
 * 2**32-1 bytes.  The header is treated as a long unsigned and is
 * encode/decoded to the network via htonl/ntohl.  The low order 31 bits
 * are a byte count of the fragment.  The highest order bit is a boolean:
 * 1 => this fragment is the last fragment of the record,
 * 0 => this fragment is followed by more fragment(s).
 *
 * The fragment/record machinery is not general;  it is constructed to
 * meet the needs of xdr and rpc based on tcp.
 */

#define LAST_FRAG (1UL << 31)

typedef struct rec_strm
  {
    caddr_t tcp_handle;
    caddr_t the_buffer;
    /*
     * out-going bits
     */
    int (*writeit) (char *, char *, int);
    caddr_t out_base;		/* output buffer (points to frag header) */
    caddr_t out_finger;		/* next output position */
    caddr_t out_boundry;	/* data cannot up to this address */
    u_int32_t *frag_header;	/* beginning of curren fragment */
    bool_t frag_sent;		/* true if buffer sent in middle of record */
    /*
     * in-coming bits
     */
    int (*readit) (char *, char *, int);
    u_long in_size;		/* fixed size of the input buffer */
    caddr_t in_base;
    caddr_t in_finger;		/* location of next byte to be had */
    caddr_t in_boundry;		/* can read up to this location */
    long fbtbc;			/* fragment bytes to be consumed */
    bool_t last_frag;
    u_int sendsize;
    u_int recvsize;
  }
RECSTREAM;

static u_int fix_buf_size (u_int) internal_function;
static bool_t skip_input_bytes (RECSTREAM *, long) internal_function;
static bool_t flush_out (RECSTREAM *, bool_t) internal_function;
static bool_t set_input_fragment (RECSTREAM *) internal_function;
static bool_t get_input_bytes (RECSTREAM *, caddr_t, int) internal_function;

/*
 * Create an xdr handle for xdrrec
 * xdrrec_create fills in xdrs.  Sendsize and recvsize are
 * send and recv buffer sizes (0 => use default).
 * tcp_handle is an opaque handle that is passed as the first parameter to
 * the procedures readit and writeit.  Readit and writeit are read and
 * write respectively.   They are like the system
 * calls expect that they take an opaque handle rather than an fd.
 */
void
xdrrec_create (XDR *xdrs, u_int sendsize,
	       u_int recvsize, caddr_t tcp_handle,
	       int (*readit) (char *, char *, int),
	       int (*writeit) (char *, char *, int))
{
  RECSTREAM *rstrm = (RECSTREAM *) mem_alloc (sizeof (RECSTREAM));
  caddr_t tmp;
  char *buf;

  sendsize = fix_buf_size (sendsize);
  recvsize = fix_buf_size (recvsize);
  buf = mem_alloc (sendsize + recvsize + BYTES_PER_XDR_UNIT);

  if (rstrm == NULL || buf == NULL)
    {
      (void) __fxprintf (NULL, "%s: %s", __func__, _("out of memory\n"));
      mem_free (rstrm, sizeof (RECSTREAM));
      mem_free (buf, sendsize + recvsize + BYTES_PER_XDR_UNIT);
      /*
       *  This is bad.  Should rework xdrrec_create to
       *  return a handle, and in this case return NULL
       */
      return;
    }
  /*
   * adjust sizes and allocate buffer quad byte aligned
   */
  rstrm->sendsize = sendsize;
  rstrm->recvsize = recvsize;
  rstrm->the_buffer = buf;
  tmp = rstrm->the_buffer;
  if ((size_t)tmp % BYTES_PER_XDR_UNIT)
    tmp += BYTES_PER_XDR_UNIT - (size_t)tmp % BYTES_PER_XDR_UNIT;
  rstrm->out_base = tmp;
  rstrm->in_base = tmp + sendsize;
  /*
   * now the rest ...
   */
  /* We have to add the cast since the `struct xdr_ops' in `struct XDR'
     is not `const'.  */
  xdrs->x_ops = (struct xdr_ops *) &xdrrec_ops;
  xdrs->x_private = (caddr_t) rstrm;
  rstrm->tcp_handle = tcp_handle;
  rstrm->readit = readit;
  rstrm->writeit = writeit;
  rstrm->out_finger = rstrm->out_boundry = rstrm->out_base;
  rstrm->frag_header = (u_int32_t *) rstrm->out_base;
  rstrm->out_finger += 4;
  rstrm->out_boundry += sendsize;
  rstrm->frag_sent = FALSE;
  rstrm->in_size = recvsize;
  rstrm->in_boundry = rstrm->in_base;
  rstrm->in_finger = (rstrm->in_boundry += recvsize);
  rstrm->fbtbc = 0;
  rstrm->last_frag = TRUE;
}
libc_hidden_nolink_sunrpc (xdrrec_create, GLIBC_2_0)


/*
 * The routines defined below are the xdr ops which will go into the
 * xdr handle filled in by xdrrec_create.
 */

static bool_t
xdrrec_getlong (XDR *xdrs, long *lp)
{
  RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
  int32_t *buflp = (int32_t *) rstrm->in_finger;
  int32_t mylong;

  /* first try the inline, fast case */
  if (rstrm->fbtbc >= BYTES_PER_XDR_UNIT &&
      rstrm->in_boundry - (char *) buflp >= BYTES_PER_XDR_UNIT)
    {
      *lp = (int32_t) ntohl (*buflp);
      rstrm->fbtbc -= BYTES_PER_XDR_UNIT;
      rstrm->in_finger += BYTES_PER_XDR_UNIT;
    }
  else
    {
      if (!xdrrec_getbytes (xdrs, (caddr_t) & mylong,
			    BYTES_PER_XDR_UNIT))
	return FALSE;
      *lp = (int32_t) ntohl (mylong);
    }
  return TRUE;
}

static bool_t
xdrrec_putlong (XDR *xdrs, const long *lp)
{
  RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
  int32_t *dest_lp = (int32_t *) rstrm->out_finger;

  if ((rstrm->out_finger += BYTES_PER_XDR_UNIT) > rstrm->out_boundry)
    {
      /*
       * this case should almost never happen so the code is
       * inefficient
       */
      rstrm->out_finger -= BYTES_PER_XDR_UNIT;
      rstrm->frag_sent = TRUE;
      if (!flush_out (rstrm, FALSE))
	return FALSE;
      dest_lp = (int32_t *) rstrm->out_finger;
      rstrm->out_finger += BYTES_PER_XDR_UNIT;
    }
  *dest_lp = htonl (*lp);
  return TRUE;
}

static bool_t	   /* must manage buffers, fragments, and records */
xdrrec_getbytes (XDR *xdrs, caddr_t addr, u_int len)
{
  RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
  u_int current;

  while (len > 0)
    {
      current = rstrm->fbtbc;
      if (current == 0)
	{
	  if (rstrm->last_frag)
	    return FALSE;
	  if (!set_input_fragment (rstrm))
	    return FALSE;
	  continue;
	}
      current = (len < current) ? len : current;
      if (!get_input_bytes (rstrm, addr, current))
	return FALSE;
      addr += current;
      rstrm->fbtbc -= current;
      len -= current;
    }
  return TRUE;
}

static bool_t
xdrrec_putbytes (XDR *xdrs, const char *addr, u_int len)
{
  RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
  u_int current;

  while (len > 0)
    {
      current = rstrm->out_boundry - rstrm->out_finger;
      current = (len < current) ? len : current;
      memcpy (rstrm->out_finger, addr, current);
      rstrm->out_finger += current;
      addr += current;
      len -= current;
      if (rstrm->out_finger == rstrm->out_boundry && len > 0)
	{
	  rstrm->frag_sent = TRUE;
	  if (!flush_out (rstrm, FALSE))
	    return FALSE;
	}
    }
  return TRUE;
}

static u_int
xdrrec_getpos (const XDR *xdrs)
{
  RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
  long pos;

  pos = __lseek ((int) (long) rstrm->tcp_handle, (long) 0, 1);
  if (pos != -1)
    switch (xdrs->x_op)
      {

      case XDR_ENCODE:
	pos += rstrm->out_finger - rstrm->out_base;
	break;

      case XDR_DECODE:
	pos -= rstrm->in_boundry - rstrm->in_finger;
	break;

      default:
	pos = (u_int) - 1;
	break;
      }
  return (u_int) pos;
}

static bool_t
xdrrec_setpos (XDR *xdrs, u_int pos)
{
  RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
  u_int currpos = xdrrec_getpos (xdrs);
  int delta = currpos - pos;
  caddr_t newpos;

  if ((int) currpos != -1)
    switch (xdrs->x_op)
      {

      case XDR_ENCODE:
	newpos = rstrm->out_finger - delta;
	if (newpos > (caddr_t) rstrm->frag_header &&
	    newpos < rstrm->out_boundry)
	  {
	    rstrm->out_finger = newpos;
	    return TRUE;
	  }
	break;

      case XDR_DECODE:
	newpos = rstrm->in_finger - delta;
	if ((delta < (int) (rstrm->fbtbc)) &&
	    (newpos <= rstrm->in_boundry) &&
	    (newpos >= rstrm->in_base))
	  {
	    rstrm->in_finger = newpos;
	    rstrm->fbtbc -= delta;
	    return TRUE;
	  }
	break;

      default:
	break;
      }
  return FALSE;
}

static int32_t *
xdrrec_inline (XDR *xdrs, u_int len)
{
  RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
  int32_t *buf = NULL;

  switch (xdrs->x_op)
    {

    case XDR_ENCODE:
      if ((rstrm->out_finger + len) <= rstrm->out_boundry)
	{
	  buf = (int32_t *) rstrm->out_finger;
	  rstrm->out_finger += len;
	}
      break;

    case XDR_DECODE:
      if ((len <= rstrm->fbtbc) &&
	  ((rstrm->in_finger + len) <= rstrm->in_boundry))
	{
	  buf = (int32_t *) rstrm->in_finger;
	  rstrm->fbtbc -= len;
	  rstrm->in_finger += len;
	}
      break;

    default:
      break;
    }
  return buf;
}

static void
xdrrec_destroy (XDR *xdrs)
{
  RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;

  mem_free (rstrm->the_buffer,
	    rstrm->sendsize + rstrm->recvsize + BYTES_PER_XDR_UNIT);
  mem_free ((caddr_t) rstrm, sizeof (RECSTREAM));
}

static bool_t
xdrrec_getint32 (XDR *xdrs, int32_t *ip)
{
  RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
  int32_t *bufip = (int32_t *) rstrm->in_finger;
  int32_t mylong;

  /* first try the inline, fast case */
  if (rstrm->fbtbc >= BYTES_PER_XDR_UNIT &&
      rstrm->in_boundry - (char *) bufip >= BYTES_PER_XDR_UNIT)
    {
      *ip = ntohl (*bufip);
      rstrm->fbtbc -= BYTES_PER_XDR_UNIT;
      rstrm->in_finger += BYTES_PER_XDR_UNIT;
    }
  else
    {
      if (!xdrrec_getbytes (xdrs, (caddr_t) &mylong,
			    BYTES_PER_XDR_UNIT))
	return FALSE;
      *ip = ntohl (mylong);
    }
  return TRUE;
}

static bool_t
xdrrec_putint32 (XDR *xdrs, const int32_t *ip)
{
  RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
  int32_t *dest_ip = (int32_t *) rstrm->out_finger;

  if ((rstrm->out_finger += BYTES_PER_XDR_UNIT) > rstrm->out_boundry)
    {
      /*
       * this case should almost never happen so the code is
       * inefficient
       */
      rstrm->out_finger -= BYTES_PER_XDR_UNIT;
      rstrm->frag_sent = TRUE;
      if (!flush_out (rstrm, FALSE))
	return FALSE;
      dest_ip = (int32_t *) rstrm->out_finger;
      rstrm->out_finger += BYTES_PER_XDR_UNIT;
    }
  *dest_ip = htonl (*ip);
  return TRUE;
}

/*
 * Exported routines to manage xdr records
 */

/*
 * Before reading (deserializing from the stream, one should always call
 * this procedure to guarantee proper record alignment.
 */
bool_t
xdrrec_skiprecord (XDR *xdrs)
{
  RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;

  while (rstrm->fbtbc > 0 || (!rstrm->last_frag))
    {
      if (!skip_input_bytes (rstrm, rstrm->fbtbc))
	return FALSE;
      rstrm->fbtbc = 0;
      if ((!rstrm->last_frag) && (!set_input_fragment (rstrm)))
	return FALSE;
    }
  rstrm->last_frag = FALSE;
  return TRUE;
}
libc_hidden_nolink_sunrpc (xdrrec_skiprecord, GLIBC_2_0)

/*
 * Lookahead function.
 * Returns TRUE iff there is no more input in the buffer
 * after consuming the rest of the current record.
 */
bool_t
xdrrec_eof (XDR *xdrs)
{
  RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;

  while (rstrm->fbtbc > 0 || (!rstrm->last_frag))
    {
      if (!skip_input_bytes (rstrm, rstrm->fbtbc))
	return TRUE;
      rstrm->fbtbc = 0;
      if ((!rstrm->last_frag) && (!set_input_fragment (rstrm)))
	return TRUE;
    }
  if (rstrm->in_finger == rstrm->in_boundry)
    return TRUE;
  return FALSE;
}
libc_hidden_nolink_sunrpc (xdrrec_eof, GLIBC_2_0)

/*
 * The client must tell the package when an end-of-record has occurred.
 * The second parameter tells whether the record should be flushed to the
 * (output) tcp stream.  (This lets the package support batched or
 * pipelined procedure calls.)  TRUE => immediate flush to tcp connection.
 */
bool_t
xdrrec_endofrecord (XDR *xdrs, bool_t sendnow)
{
  RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
  u_long len;		/* fragment length */

  if (sendnow || rstrm->frag_sent
      || rstrm->out_finger + BYTES_PER_XDR_UNIT >= rstrm->out_boundry)
    {
      rstrm->frag_sent = FALSE;
      return flush_out (rstrm, TRUE);
    }
  len = (rstrm->out_finger - (char *) rstrm->frag_header
	 - BYTES_PER_XDR_UNIT);
  *rstrm->frag_header = htonl ((u_long) len | LAST_FRAG);
  rstrm->frag_header = (u_int32_t *) rstrm->out_finger;
  rstrm->out_finger += BYTES_PER_XDR_UNIT;
  return TRUE;
}
libc_hidden_nolink_sunrpc (xdrrec_endofrecord, GLIBC_2_0)


/*
 * Internal useful routines
 */
static bool_t
internal_function
flush_out (RECSTREAM *rstrm, bool_t eor)
{
  u_long eormask = (eor == TRUE) ? LAST_FRAG : 0;
  u_long len = (rstrm->out_finger - (char *) rstrm->frag_header
		- BYTES_PER_XDR_UNIT);

  *rstrm->frag_header = htonl (len | eormask);
  len = rstrm->out_finger - rstrm->out_base;
  if ((*(rstrm->writeit)) (rstrm->tcp_handle, rstrm->out_base, (int) len)
      != (int) len)
    return FALSE;
  rstrm->frag_header = (u_int32_t *) rstrm->out_base;
  rstrm->out_finger = (caddr_t) rstrm->out_base + BYTES_PER_XDR_UNIT;
  return TRUE;
}

static bool_t	/* knows nothing about records!  Only about input buffers */
fill_input_buf (RECSTREAM *rstrm)
{
  caddr_t where;
  size_t i;
  int len;

  where = rstrm->in_base;
  i = (size_t) rstrm->in_boundry % BYTES_PER_XDR_UNIT;
  where += i;
  len = rstrm->in_size - i;
  if ((len = (*(rstrm->readit)) (rstrm->tcp_handle, where, len)) == -1)
    return FALSE;
  rstrm->in_finger = where;
  where += len;
  rstrm->in_boundry = where;
  return TRUE;
}

static bool_t	/* knows nothing about records!  Only about input buffers */
internal_function
get_input_bytes (RECSTREAM *rstrm, caddr_t addr, int len)
{
  int current;

  while (len > 0)
    {
      current = rstrm->in_boundry - rstrm->in_finger;
      if (current == 0)
	{
	  if (!fill_input_buf (rstrm))
	    return FALSE;
	  continue;
	}
      current = (len < current) ? len : current;
      memcpy (addr, rstrm->in_finger, current);
      rstrm->in_finger += current;
      addr += current;
      len -= current;
    }
  return TRUE;
}

static bool_t /* next two bytes of the input stream are treated as a header */
internal_function
set_input_fragment (RECSTREAM *rstrm)
{
  uint32_t header;

  if (! get_input_bytes (rstrm, (caddr_t)&header, BYTES_PER_XDR_UNIT))
    return FALSE;
  header = ntohl (header);
  rstrm->last_frag = ((header & LAST_FRAG) == 0) ? FALSE : TRUE;
  /*
   * Sanity check. Try not to accept wildly incorrect fragment
   * sizes. Unfortunately, only a size of zero can be identified as
   * 'wildely incorrect', and this only, if it is not the last
   * fragment of a message. Ridiculously large fragment sizes may look
   * wrong, but we don't have any way to be certain that they aren't
   * what the client actually intended to send us. Many existing RPC
   * implementations may sent a fragment of size zero as the last
   * fragment of a message.
   */
  if (header == 0)
    return FALSE;
  rstrm->fbtbc = header & ~LAST_FRAG;
  return TRUE;
}

static bool_t	/* consumes input bytes; knows nothing about records! */
internal_function
skip_input_bytes (RECSTREAM *rstrm, long cnt)
{
  int current;

  while (cnt > 0)
    {
      current = rstrm->in_boundry - rstrm->in_finger;
      if (current == 0)
	{
	  if (!fill_input_buf (rstrm))
	    return FALSE;
	  continue;
	}
      current = (cnt < current) ? cnt : current;
      rstrm->in_finger += current;
      cnt -= current;
    }
  return TRUE;
}

static u_int
internal_function
fix_buf_size (u_int s)
{
  if (s < 100)
    s = 4000;
  return RNDUP (s);
}