lib/libc/xdr/xdr_rec.c

   1 /*      $NetBSD: xdr_rec.c,v 1.18 2000/07/06 03:10:35 christos Exp $    */
   2
   3 /*-
   4  * SPDX-License-Identifier: BSD-3-Clause
   5  *
   6  * Copyright (c) 2010, Oracle America, Inc.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions are
  10  * met:
  11  *
  12  *     * Redistributions of source code must retain the above copyright
  13  *       notice, this list of conditions and the following disclaimer.
  14  *     * Redistributions in binary form must reproduce the above
  15  *       copyright notice, this list of conditions and the following
  16  *       disclaimer in the documentation and/or other materials
  17  *       provided with the distribution.
  18  *     * Neither the name of the "Oracle America, Inc." nor the names of its
  19  *       contributors may be used to endorse or promote products derived
  20  *       from this software without specific prior written permission.
  21  *
  22  *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  23  *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  24  *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  25  *   FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
  26  *   COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
  27  *   INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  28  *   DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
  29  *   GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  30  *   INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
  31  *   WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  32  *   NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  33  *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  34  */
  35
  36 /*
  37  * xdr_rec.c, Implements TCP/IP based XDR streams with a "record marking"
  38  * layer above tcp (for rpc's use).
  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).  Thegh 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 "namespace.h"
  52 #include <sys/types.h>
  53
  54 #include <netinet/in.h>
  55
  56 #include <err.h>
  57 #include <stdio.h>
  58 #include <stdlib.h>
  59 #include <string.h>
  60
  61 #include <rpc/types.h>
  62 #include <rpc/xdr.h>
  63 #include <rpc/auth.h>
  64 #include <rpc/svc.h>
  65 #include <rpc/clnt.h>
  66 #include <sys/stddef.h>
  67 #include "un-namespace.h"
  68 #include "rpc_com.h"
  69
  70 static bool_t   xdrrec_getlong(XDR *, long *);
  71 static bool_t   xdrrec_putlong(XDR *, const long *);
  72 static bool_t   xdrrec_getbytes(XDR *, char *, u_int);
  73
  74 static bool_t   xdrrec_putbytes(XDR *, const char *, u_int);
  75 static u_int    xdrrec_getpos(XDR *);
  76 static bool_t   xdrrec_setpos(XDR *, u_int);
  77 static int32_t *xdrrec_inline(XDR *, u_int);
  78 static void     xdrrec_destroy(XDR *);
  79
  80 static const struct  xdr_ops xdrrec_ops = {
  81         xdrrec_getlong,
  82         xdrrec_putlong,
  83         xdrrec_getbytes,
  84         xdrrec_putbytes,
  85         xdrrec_getpos,
  86         xdrrec_setpos,
  87         xdrrec_inline,
  88         xdrrec_destroy
  89 };
  90
  91 /*
  92  * A record is composed of one or more record fragments.
  93  * A record fragment is a four-byte header followed by zero to
  94  * 2**32-1 bytes.  The header is treated as a long unsigned and is
  95  * encode/decoded to the network via htonl/ntohl.  The low order 31 bits
  96  * are a byte count of the fragment.  The highest order bit is a boolean:
  97  * 1 => this fragment is the last fragment of the record,
  98  * 0 => this fragment is followed by more fragment(s).
  99  *
 100  * The fragment/record machinery is not general;  it is constructed to
 101  * meet the needs of xdr and rpc based on tcp.
 102  */
 103
 104 #define LAST_FRAG ((u_int32_t)(1U << 31))
 105
 106 typedef struct rec_strm {
 107         char *tcp_handle;
 108         /*
 109          * out-goung bits
 110          */
 111         int (*writeit)(void *, void *, int);
 112         char *out_base; /* output buffer (points to frag header) */
 113         char *out_finger;       /* next output position */
 114         char *out_boundry;      /* data cannot up to this address */
 115         u_int32_t *frag_header; /* beginning of current fragment */
 116         bool_t frag_sent;       /* true if buffer sent in middle of record */
 117         /*
 118          * in-coming bits
 119          */
 120         int (*readit)(void *, void *, int);
 121         u_long in_size; /* fixed size of the input buffer */
 122         char *in_base;
 123         char *in_finger;        /* location of next byte to be had */
 124         char *in_boundry;       /* can read up to this location */
 125         long fbtbc;             /* fragment bytes to be consumed */
 126         bool_t last_frag;
 127         u_int sendsize;
 128         u_int recvsize;
 129
 130         bool_t nonblock;
 131         bool_t in_haveheader;
 132         u_int32_t in_header;
 133         char *in_hdrp;
 134         int in_hdrlen;
 135         int in_reclen;
 136         int in_received;
 137         int in_maxrec;
 138 } RECSTREAM;
 139
 140 static u_int    fix_buf_size(u_int);
 141 static bool_t   flush_out(RECSTREAM *, bool_t);
 142 static bool_t   fill_input_buf(RECSTREAM *);
 143 static bool_t   get_input_bytes(RECSTREAM *, char *, int);
 144 static bool_t   set_input_fragment(RECSTREAM *);
 145 static bool_t   skip_input_bytes(RECSTREAM *, long);
 146 static bool_t   realloc_stream(RECSTREAM *, int);
 147
 148
 149 /*
 150  * Create an xdr handle for xdrrec
 151  * xdrrec_create fills in xdrs.  Sendsize and recvsize are
 152  * send and recv buffer sizes (0 => use default).
 153  * tcp_handle is an opaque handle that is passed as the first parameter to
 154  * the procedures readit and writeit.  Readit and writeit are read and
 155  * write respectively.   They are like the system
 156  * calls expect that they take an opaque handle rather than an fd.
 157  */
 158 void
 159 xdrrec_create(XDR *xdrs, u_int sendsize, u_int recvsize, void *tcp_handle,
 160     int (*readit)(void *, void *, int), int (*writeit)(void *, void *, int))
 161 /*
 162  *      XDR *xdrs;
 163  *      u_int sendsize;
 164  *      u_int recvsize;
 165  *      void *tcp_handle;
 166  *      // like read, but pass it a tcp_handle, not sock
 167  *      int (*readit)(void *, void *, int);
 168  *      // like write, but pass it a tcp_handle, not sock
 169  *      int (*writeit)(void *, void *, int);
 170  */
 171 {
 172         RECSTREAM *rstrm = mem_alloc(sizeof(RECSTREAM));
 173
 174         if (rstrm == NULL) {
 175                 warnx("xdrrec_create: out of memory");
 176                 /*
 177                  *  This is bad.  Should rework xdrrec_create to
 178                  *  return a handle, and in this case return NULL
 179                  */
 180                 return;
 181         }
 182         rstrm->sendsize = sendsize = fix_buf_size(sendsize);
 183         rstrm->out_base = mem_alloc(rstrm->sendsize);
 184         if (rstrm->out_base == NULL) {
 185                 warnx("xdrrec_create: out of memory");
 186                 mem_free(rstrm, sizeof(RECSTREAM));
 187                 return;
 188         }
 189         rstrm->recvsize = recvsize = fix_buf_size(recvsize);
 190         rstrm->in_base = mem_alloc(recvsize);
 191         if (rstrm->in_base == NULL) {
 192                 warnx("xdrrec_create: out of memory");
 193                 mem_free(rstrm->out_base, sendsize);
 194                 mem_free(rstrm, sizeof(RECSTREAM));
 195                 return;
 196         }
 197         /*
 198          * now the rest ...
 199          */
 200         xdrs->x_ops = &xdrrec_ops;
 201         xdrs->x_private = rstrm;
 202         rstrm->tcp_handle = tcp_handle;
 203         rstrm->readit = readit;
 204         rstrm->writeit = writeit;
 205         rstrm->out_finger = rstrm->out_boundry = rstrm->out_base;
 206         rstrm->frag_header = (u_int32_t *)(void *)rstrm->out_base;
 207         rstrm->out_finger += sizeof(u_int32_t);
 208         rstrm->out_boundry += sendsize;
 209         rstrm->frag_sent = FALSE;
 210         rstrm->in_size = recvsize;
 211         rstrm->in_boundry = rstrm->in_base;
 212         rstrm->in_finger = (rstrm->in_boundry += recvsize);
 213         rstrm->fbtbc = 0;
 214         rstrm->last_frag = TRUE;
 215         rstrm->in_haveheader = FALSE;
 216         rstrm->in_hdrlen = 0;
 217         rstrm->in_hdrp = (char *)(void *)&rstrm->in_header;
 218         rstrm->nonblock = FALSE;
 219         rstrm->in_reclen = 0;
 220         rstrm->in_received = 0;
 221 }
 222
 223
 224 /*
 225  * The reoutines defined below are the xdr ops which will go into the
 226  * xdr handle filled in by xdrrec_create.
 227  */
 228
 229 static bool_t
 230 xdrrec_getlong(XDR *xdrs, long *lp)
 231 {
 232         RECSTREAM *rstrm = (RECSTREAM *)(xdrs->x_private);
 233         int32_t *buflp = (int32_t *)(void *)(rstrm->in_finger);
 234         int32_t mylong;
 235
 236         /* first try the inline, fast case */
 237         if ((rstrm->fbtbc >= sizeof(int32_t)) &&
 238                 (((long)rstrm->in_boundry - (long)buflp) >= sizeof(int32_t))) {
 239                 *lp = (long)ntohl((u_int32_t)(*buflp));
 240                 rstrm->fbtbc -= sizeof(int32_t);
 241                 rstrm->in_finger += sizeof(int32_t);
 242         } else {
 243                 if (! xdrrec_getbytes(xdrs, (char *)(void *)&mylong,
 244                     sizeof(int32_t)))
 245                         return (FALSE);
 246                 *lp = (long)ntohl((u_int32_t)mylong);
 247         }
 248         return (TRUE);
 249 }
 250
 251 static bool_t
 252 xdrrec_putlong(XDR *xdrs, const long *lp)
 253 {
 254         RECSTREAM *rstrm = (RECSTREAM *)(xdrs->x_private);
 255         int32_t *dest_lp = ((int32_t *)(void *)(rstrm->out_finger));
 256
 257         if ((rstrm->out_finger += sizeof(int32_t)) > rstrm->out_boundry) {
 258                 /*
 259                  * this case should almost never happen so the code is
 260                  * inefficient
 261                  */
 262                 rstrm->out_finger -= sizeof(int32_t);
 263                 rstrm->frag_sent = TRUE;
 264                 if (! flush_out(rstrm, FALSE))
 265                         return (FALSE);
 266                 dest_lp = ((int32_t *)(void *)(rstrm->out_finger));
 267                 rstrm->out_finger += sizeof(int32_t);
 268         }
 269         *dest_lp = (int32_t)htonl((u_int32_t)(*lp));
 270         return (TRUE);
 271 }
 272
 273 static bool_t  /* must manage buffers, fragments, and records */
 274 xdrrec_getbytes(XDR *xdrs, char *addr, u_int len)
 275 {
 276         RECSTREAM *rstrm = (RECSTREAM *)(xdrs->x_private);
 277         int current;
 278
 279         while (len > 0) {
 280                 current = (int)rstrm->fbtbc;
 281                 if (current == 0) {
 282                         if (rstrm->last_frag)
 283                                 return (FALSE);
 284                         if (! set_input_fragment(rstrm))
 285                                 return (FALSE);
 286                         continue;
 287                 }
 288                 current = (len < current) ? len : current;
 289                 if (! get_input_bytes(rstrm, addr, current))
 290                         return (FALSE);
 291                 addr += current;
 292                 rstrm->fbtbc -= current;
 293                 len -= current;
 294         }
 295         return (TRUE);
 296 }
 297
 298 static bool_t
 299 xdrrec_putbytes(XDR *xdrs, const char *addr, u_int len)
 300 {
 301         RECSTREAM *rstrm = (RECSTREAM *)(xdrs->x_private);
 302         size_t current;
 303
 304         while (len > 0) {
 305                 current = (size_t)((u_long)rstrm->out_boundry -
 306                     (u_long)rstrm->out_finger);
 307                 current = (len < current) ? len : current;
 308                 memmove(rstrm->out_finger, addr, current);
 309                 rstrm->out_finger += current;
 310                 addr += current;
 311                 len -= current;
 312                 if (rstrm->out_finger == rstrm->out_boundry) {
 313                         rstrm->frag_sent = TRUE;
 314                         if (! flush_out(rstrm, FALSE))
 315                                 return (FALSE);
 316                 }
 317         }
 318         return (TRUE);
 319 }
 320
 321 static u_int
 322 xdrrec_getpos(XDR *xdrs)
 323 {
 324         RECSTREAM *rstrm = (RECSTREAM *)xdrs->x_private;
 325         off_t pos;
 326
 327         pos = lseek((int)(u_long)rstrm->tcp_handle, (off_t)0, 1);
 328         if (pos == -1)
 329                 pos = 0;
 330         switch (xdrs->x_op) {
 331
 332         case XDR_ENCODE:
 333                 pos += rstrm->out_finger - rstrm->out_base;
 334                 break;
 335
 336         case XDR_DECODE:
 337                 pos -= rstrm->in_boundry - rstrm->in_finger;
 338                 break;
 339
 340         default:
 341                 pos = (off_t) -1;
 342                 break;
 343         }
 344         return ((u_int) pos);
 345 }
 346
 347 static bool_t
 348 xdrrec_setpos(XDR *xdrs, u_int pos)
 349 {
 350         RECSTREAM *rstrm = (RECSTREAM *)xdrs->x_private;
 351         u_int currpos = xdrrec_getpos(xdrs);
 352         int delta = currpos - pos;
 353         char *newpos;
 354
 355         if ((int)currpos != -1)
 356                 switch (xdrs->x_op) {
 357
 358                 case XDR_ENCODE:
 359                         newpos = rstrm->out_finger - delta;
 360                         if ((newpos > (char *)(void *)(rstrm->frag_header)) &&
 361                                 (newpos < rstrm->out_boundry)) {
 362                                 rstrm->out_finger = newpos;
 363                                 return (TRUE);
 364                         }
 365                         break;
 366
 367                 case XDR_DECODE:
 368                         newpos = rstrm->in_finger - delta;
 369                         if ((delta < (int)(rstrm->fbtbc)) &&
 370                                 (newpos <= rstrm->in_boundry) &&
 371                                 (newpos >= rstrm->in_base)) {
 372                                 rstrm->in_finger = newpos;
 373                                 rstrm->fbtbc -= delta;
 374                                 return (TRUE);
 375                         }
 376                         break;
 377
 378                 case XDR_FREE:
 379                         break;
 380                 }
 381         return (FALSE);
 382 }
 383
 384 static int32_t *
 385 xdrrec_inline(XDR *xdrs, u_int len)
 386 {
 387         RECSTREAM *rstrm = (RECSTREAM *)xdrs->x_private;
 388         int32_t *buf = NULL;
 389
 390         switch (xdrs->x_op) {
 391
 392         case XDR_ENCODE:
 393                 if ((rstrm->out_finger + len) <= rstrm->out_boundry) {
 394                         buf = (int32_t *)(void *)rstrm->out_finger;
 395                         rstrm->out_finger += len;
 396                 }
 397                 break;
 398
 399         case XDR_DECODE:
 400                 if ((len <= rstrm->fbtbc) &&
 401                         ((rstrm->in_finger + len) <= rstrm->in_boundry)) {
 402                         buf = (int32_t *)(void *)rstrm->in_finger;
 403                         rstrm->fbtbc -= len;
 404                         rstrm->in_finger += len;
 405                 }
 406                 break;
 407
 408         case XDR_FREE:
 409                 break;
 410         }
 411         return (buf);
 412 }
 413
 414 static void
 415 xdrrec_destroy(XDR *xdrs)
 416 {
 417         RECSTREAM *rstrm = (RECSTREAM *)xdrs->x_private;
 418
 419         mem_free(rstrm->out_base, rstrm->sendsize);
 420         mem_free(rstrm->in_base, rstrm->recvsize);
 421         mem_free(rstrm, sizeof(RECSTREAM));
 422 }
 423
 424
 425 /*
 426  * Exported routines to manage xdr records
 427  */
 428
 429 /*
 430  * Before reading (deserializing from the stream, one should always call
 431  * this procedure to guarantee proper record alignment.
 432  */
 433 bool_t
 434 xdrrec_skiprecord(XDR *xdrs)
 435 {
 436         RECSTREAM *rstrm = (RECSTREAM *)(xdrs->x_private);
 437         enum xprt_stat xstat;
 438
 439         if (rstrm->nonblock) {
 440                 if (__xdrrec_getrec(xdrs, &xstat, FALSE)) {
 441                         rstrm->fbtbc = 0;
 442                         return TRUE;
 443                 }
 444                 if (rstrm->in_finger == rstrm->in_boundry &&
 445                     xstat == XPRT_MOREREQS) {
 446                         rstrm->fbtbc = 0;
 447                         return TRUE;
 448                 }
 449                 return FALSE;
 450         }
 451
 452         while (rstrm->fbtbc > 0 || (! rstrm->last_frag)) {
 453                 if (! skip_input_bytes(rstrm, rstrm->fbtbc))
 454                         return (FALSE);
 455                 rstrm->fbtbc = 0;
 456                 if ((! rstrm->last_frag) && (! set_input_fragment(rstrm)))
 457                         return (FALSE);
 458         }
 459         rstrm->last_frag = FALSE;
 460         return (TRUE);
 461 }
 462
 463 /*
 464  * Look ahead function.
 465  * Returns TRUE iff there is no more input in the buffer
 466  * after consuming the rest of the current record.
 467  */
 468 bool_t
 469 xdrrec_eof(XDR *xdrs)
 470 {
 471         RECSTREAM *rstrm = (RECSTREAM *)(xdrs->x_private);
 472
 473         while (rstrm->fbtbc > 0 || (! rstrm->last_frag)) {
 474                 if (! skip_input_bytes(rstrm, rstrm->fbtbc))
 475                         return (TRUE);
 476                 rstrm->fbtbc = 0;
 477                 if ((! rstrm->last_frag) && (! set_input_fragment(rstrm)))
 478                         return (TRUE);
 479         }
 480         if (rstrm->in_finger == rstrm->in_boundry)
 481                 return (TRUE);
 482         return (FALSE);
 483 }
 484
 485 /*
 486  * The client must tell the package when an end-of-record has occurred.
 487  * The second paraemters tells whether the record should be flushed to the
 488  * (output) tcp stream.  (This let's the package support batched or
 489  * pipelined procedure calls.)  TRUE => immediate flush to tcp connection.
 490  */
 491 bool_t
 492 xdrrec_endofrecord(XDR *xdrs, bool_t sendnow)
 493 {
 494         RECSTREAM *rstrm = (RECSTREAM *)(xdrs->x_private);
 495         u_long len;  /* fragment length */
 496
 497         if (sendnow || rstrm->frag_sent ||
 498                 ((u_long)rstrm->out_finger + sizeof(u_int32_t) >=
 499                 (u_long)rstrm->out_boundry)) {
 500                 rstrm->frag_sent = FALSE;
 501                 return (flush_out(rstrm, TRUE));
 502         }
 503         len = (u_long)(rstrm->out_finger) - (u_long)(rstrm->frag_header) -
 504            sizeof(u_int32_t);
 505         *(rstrm->frag_header) = htonl((u_int32_t)len | LAST_FRAG);
 506         rstrm->frag_header = (u_int32_t *)(void *)rstrm->out_finger;
 507         rstrm->out_finger += sizeof(u_int32_t);
 508         return (TRUE);
 509 }
 510
 511 /*
 512  * Fill the stream buffer with a record for a non-blocking connection.
 513  * Return true if a record is available in the buffer, false if not.
 514  */
 515 bool_t
 516 __xdrrec_getrec(XDR *xdrs, enum xprt_stat *statp, bool_t expectdata)
 517 {
 518         RECSTREAM *rstrm = (RECSTREAM *)(xdrs->x_private);
 519         ssize_t n;
 520         int fraglen;
 521
 522         if (!rstrm->in_haveheader) {
 523                 n = rstrm->readit(rstrm->tcp_handle, rstrm->in_hdrp,
 524                     (int)sizeof (rstrm->in_header) - rstrm->in_hdrlen);
 525                 if (n == 0) {
 526                         *statp = expectdata ? XPRT_DIED : XPRT_IDLE;
 527                         return FALSE;
 528                 }
 529                 if (n < 0) {
 530                         *statp = XPRT_DIED;
 531                         return FALSE;
 532                 }
 533                 rstrm->in_hdrp += n;
 534                 rstrm->in_hdrlen += n;
 535                 if (rstrm->in_hdrlen < sizeof (rstrm->in_header)) {
 536                         *statp = XPRT_MOREREQS;
 537                         return FALSE;
 538                 }
 539                 rstrm->in_header = ntohl(rstrm->in_header);
 540                 fraglen = (int)(rstrm->in_header & ~LAST_FRAG);
 541                 if (fraglen == 0 || fraglen > rstrm->in_maxrec ||
 542                     (rstrm->in_reclen + fraglen) > rstrm->in_maxrec) {
 543                         *statp = XPRT_DIED;
 544                         return FALSE;
 545                 }
 546                 rstrm->in_reclen += fraglen;
 547                 if (rstrm->in_reclen > rstrm->recvsize)
 548                         realloc_stream(rstrm, rstrm->in_reclen);
 549                 if (rstrm->in_header & LAST_FRAG) {
 550                         rstrm->in_header &= ~LAST_FRAG;
 551                         rstrm->last_frag = TRUE;
 552                 }
 553                 /*
 554                  * We can only reasonably expect to read once from a
 555                  * non-blocking stream. Reading the fragment header
 556                  * may have drained the stream.
 557                  */
 558                 expectdata = FALSE;
 559         }
 560
 561         n =  rstrm->readit(rstrm->tcp_handle,
 562             rstrm->in_base + rstrm->in_received,
 563             (rstrm->in_reclen - rstrm->in_received));
 564
 565         if (n < 0) {
 566                 *statp = XPRT_DIED;
 567                 return FALSE;
 568         }
 569
 570         if (n == 0) {
 571                 *statp = expectdata ? XPRT_DIED : XPRT_IDLE;
 572                 return FALSE;
 573         }
 574
 575         rstrm->in_received += n;
 576
 577         if (rstrm->in_received == rstrm->in_reclen) {
 578                 rstrm->in_haveheader = FALSE;
 579                 rstrm->in_hdrp = (char *)(void *)&rstrm->in_header;
 580                 rstrm->in_hdrlen = 0;
 581                 if (rstrm->last_frag) {
 582                         rstrm->fbtbc = rstrm->in_reclen;
 583                         rstrm->in_boundry = rstrm->in_base + rstrm->in_reclen;
 584                         rstrm->in_finger = rstrm->in_base;
 585                         rstrm->in_reclen = rstrm->in_received = 0;
 586                         *statp = XPRT_MOREREQS;
 587                         return TRUE;
 588                 }
 589         }
 590
 591         *statp = XPRT_MOREREQS;
 592         return FALSE;
 593 }
 594
 595 bool_t
 596 __xdrrec_setnonblock(XDR *xdrs, int maxrec)
 597 {
 598         RECSTREAM *rstrm = (RECSTREAM *)(xdrs->x_private);
 599
 600         rstrm->nonblock = TRUE;
 601         if (maxrec == 0)
 602                 maxrec = rstrm->recvsize;
 603         rstrm->in_maxrec = maxrec;
 604         return TRUE;
 605 }
 606
 607 /*
 608  * Internal useful routines
 609  */
 610 static bool_t
 611 flush_out(RECSTREAM *rstrm, bool_t eor)
 612 {
 613         u_int32_t eormask = (eor == TRUE) ? LAST_FRAG : 0;
 614         u_int32_t len = (u_int32_t)((u_long)(rstrm->out_finger) -
 615                 (u_long)(rstrm->frag_header) - sizeof(u_int32_t));
 616
 617         *(rstrm->frag_header) = htonl(len | eormask);
 618         len = (u_int32_t)((u_long)(rstrm->out_finger) -
 619             (u_long)(rstrm->out_base));
 620         if ((*(rstrm->writeit))(rstrm->tcp_handle, rstrm->out_base, (int)len)
 621                 != (int)len)
 622                 return (FALSE);
 623         rstrm->frag_header = (u_int32_t *)(void *)rstrm->out_base;
 624         rstrm->out_finger = (char *)rstrm->out_base + sizeof(u_int32_t);
 625         return (TRUE);
 626 }
 627
 628 static bool_t  /* knows nothing about records!  Only about input buffers */
 629 fill_input_buf(RECSTREAM *rstrm)
 630 {
 631         char *where;
 632         u_int32_t i;
 633         int len;
 634
 635         if (rstrm->nonblock)
 636                 return FALSE;
 637
 638         where = rstrm->in_base;
 639         i = (u_int32_t)((u_long)rstrm->in_boundry % BYTES_PER_XDR_UNIT);
 640         where += i;
 641         len = (u_int32_t)(rstrm->in_size - i);
 642         if ((len = (*(rstrm->readit))(rstrm->tcp_handle, where, len)) == -1)
 643                 return (FALSE);
 644         rstrm->in_finger = where;
 645         where += len;
 646         rstrm->in_boundry = where;
 647         return (TRUE);
 648 }
 649
 650 static bool_t  /* knows nothing about records!  Only about input buffers */
 651 get_input_bytes(RECSTREAM *rstrm, char *addr, int len)
 652 {
 653         size_t current;
 654
 655         if (rstrm->nonblock) {
 656                 if (len > (int)(rstrm->in_boundry - rstrm->in_finger))
 657                         return FALSE;
 658                 memcpy(addr, rstrm->in_finger, (size_t)len);
 659                 rstrm->in_finger += len;
 660                 return TRUE;
 661         }
 662
 663         while (len > 0) {
 664                 current = (size_t)((long)rstrm->in_boundry -
 665                     (long)rstrm->in_finger);
 666                 if (current == 0) {
 667                         if (! fill_input_buf(rstrm))
 668                                 return (FALSE);
 669                         continue;
 670                 }
 671                 current = (len < current) ? len : current;
 672                 memmove(addr, rstrm->in_finger, current);
 673                 rstrm->in_finger += current;
 674                 addr += current;
 675                 len -= current;
 676         }
 677         return (TRUE);
 678 }
 679
 680 static bool_t  /* next two bytes of the input stream are treated as a header */
 681 set_input_fragment(RECSTREAM *rstrm)
 682 {
 683         u_int32_t header;
 684
 685         if (rstrm->nonblock)
 686                 return FALSE;
 687         if (! get_input_bytes(rstrm, (char *)(void *)&header, sizeof(header)))
 688                 return (FALSE);
 689         header = ntohl(header);
 690         rstrm->last_frag = ((header & LAST_FRAG) == 0) ? FALSE : TRUE;
 691         /*
 692          * Sanity check. Try not to accept wildly incorrect
 693          * record sizes. Unfortunately, the only record size
 694          * we can positively identify as being 'wildly incorrect'
 695          * is zero. Ridiculously large record sizes may look wrong,
 696          * but we don't have any way to be certain that they aren't
 697          * what the client actually intended to send us.
 698          */
 699         if (header == 0)
 700                 return(FALSE);
 701         rstrm->fbtbc = header & (~LAST_FRAG);
 702         return (TRUE);
 703 }
 704
 705 static bool_t  /* consumes input bytes; knows nothing about records! */
 706 skip_input_bytes(RECSTREAM *rstrm, long cnt)
 707 {
 708         u_int32_t current;
 709
 710         while (cnt > 0) {
 711                 current = (size_t)((long)rstrm->in_boundry -
 712                     (long)rstrm->in_finger);
 713                 if (current == 0) {
 714                         if (! fill_input_buf(rstrm))
 715                                 return (FALSE);
 716                         continue;
 717                 }
 718                 current = (u_int32_t)((cnt < current) ? cnt : current);
 719                 rstrm->in_finger += current;
 720                 cnt -= current;
 721         }
 722         return (TRUE);
 723 }
 724
 725 static u_int
 726 fix_buf_size(u_int s)
 727 {
 728
 729         if (s < 100)
 730                 s = 4000;
 731         return (RNDUP(s));
 732 }
 733
 734 /*
 735  * Reallocate the input buffer for a non-block stream.
 736  */
 737 static bool_t
 738 realloc_stream(RECSTREAM *rstrm, int size)
 739 {
 740         ptrdiff_t diff;
 741         char *buf;
 742
 743         if (size > rstrm->recvsize) {
 744                 buf = realloc(rstrm->in_base, (size_t)size);
 745                 if (buf == NULL)
 746                         return FALSE;
 747                 diff = buf - rstrm->in_base;
 748                 rstrm->in_finger += diff;
 749                 rstrm->in_base = buf;
 750                 rstrm->in_boundry = buf + size;
 751                 rstrm->recvsize = size;
 752                 rstrm->in_size = size;
 753         }
 754
 755         return TRUE;
 756 }