src/xdr_rec.c

   1
   2 /*
   3  * Copyright (c) 2009, Sun Microsystems, Inc.
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions are met:
   8  * - Redistributions of source code must retain the above copyright notice,
   9  *   this list of conditions and the following disclaimer.
  10  * - Redistributions in binary form must reproduce the above copyright notice,
  11  *   this list of conditions and the following disclaimer in the documentation
  12  *   and/or other materials provided with the distribution.
  13  * - Neither the name of Sun Microsystems, Inc. nor the names of its
  14  *   contributors may be used to endorse or promote products derived
  15  *   from this software without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  18  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
  21  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  22  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  23  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  24  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  25  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  26  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  27  * POSSIBILITY OF SUCH DAMAGE.
  28  */
  29
  30 #include <sys/cdefs.h>
  31 #include <sys/cdefs.h>
  32
  33 /*
  34  * xdr_rec.c, Implements TCP/IP based XDR streams with a "record marking"
  35  * layer above tcp (for rpc's use).
  36  *
  37  * Copyright (C) 1984, Sun Microsystems, Inc.
  38  *
  39  * These routines interface XDRSTREAMS to a tcp/ip connection.
  40  * There is a record marking layer between the xdr stream
  41  * and the tcp transport level.  A record is composed on one or more
  42  * record fragments.  A record fragment is a thirty-two bit header followed
  43  * by n bytes of data, where n is contained in the header.  The header
  44  * is represented as a htonl(u_long).  Thegh order bit encodes
  45  * whether or not the fragment is the last fragment of the record
  46  * (1 => fragment is last, 0 => more fragments to follow.
  47  * The other 31 bits encode the byte length of the fragment.
  48  */
  49
  50 #include <sys/types.h>
  51
  52 #include <netinet/in.h>
  53
  54 #include <err.h>
  55 #include <stdio.h>
  56 #include <stdlib.h>
  57 #include <string.h>
  58
  59 #include <rpc/types.h>
  60 #include <rpc/xdr.h>
  61 #include <rpc/auth.h>
  62 #include <rpc/svc_auth.h>
  63 #include <rpc/svc.h>
  64 #include <rpc/clnt.h>
  65 #include <stddef.h>
  66 #include "rpc_com.h"
  67 #include <unistd.h>
  68 static bool_t   xdrrec_getlong(XDR *, long *);
  69 static bool_t   xdrrec_putlong(XDR *, const long *);
  70 static bool_t   xdrrec_getbytes(XDR *, char *, u_int);
  71
  72 static bool_t   xdrrec_putbytes(XDR *, const char *, u_int);
  73 static u_int    xdrrec_getpos(XDR *);
  74 static bool_t   xdrrec_setpos(XDR *, u_int);
  75 static int32_t *xdrrec_inline(XDR *, u_int);
  76 static void     xdrrec_destroy(XDR *);
  77
  78 static const struct  xdr_ops xdrrec_ops = {
  79         xdrrec_getlong,
  80         xdrrec_putlong,
  81         xdrrec_getbytes,
  82         xdrrec_putbytes,
  83         xdrrec_getpos,
  84         xdrrec_setpos,
  85         xdrrec_inline,
  86         xdrrec_destroy
  87 };
  88
  89 /*
  90  * A record is composed of one or more record fragments.
  91  * A record fragment is a four-byte header followed by zero to
  92  * 2**32-1 bytes.  The header is treated as a long unsigned and is
  93  * encode/decoded to the network via htonl/ntohl.  The low order 31 bits
  94  * are a byte count of the fragment.  The highest order bit is a boolean:
  95  * 1 => this fragment is the last fragment of the record,
  96  * 0 => this fragment is followed by more fragment(s).
  97  *
  98  * The fragment/record machinery is not general;  it is constructed to
  99  * meet the needs of xdr and rpc based on tcp.
 100  */
 101
 102 #define LAST_FRAG ((u_int32_t)(1 << 31))
 103
 104 typedef struct rec_strm {
 105         char *tcp_handle;
 106         /*
 107          * out-goung bits
 108          */
 109         int (*writeit)(void *, void *, int);
 110         char *out_base; /* output buffer (points to frag header) */
 111         char *out_finger;       /* next output position */
 112         char *out_boundry;      /* data cannot up to this address */
 113         u_int32_t *frag_header; /* beginning of curren fragment */
 114         bool_t frag_sent;       /* true if buffer sent in middle of record */
 115         /*
 116          * in-coming bits
 117          */
 118         int (*readit)(void *, void *, int);
 119         u_long in_size; /* fixed size of the input buffer */
 120         char *in_base;
 121         char *in_finger;        /* location of next byte to be had */
 122         char *in_boundry;       /* can read up to this location */
 123         long fbtbc;             /* fragment bytes to be consumed */
 124         bool_t last_frag;
 125         u_int sendsize;
 126         u_int recvsize;
 127
 128         bool_t nonblock;
 129         bool_t in_haveheader;
 130         u_int32_t in_header;
 131         char *in_hdrp;
 132         int in_hdrlen;
 133         int in_reclen;
 134         int in_received;
 135         int in_maxrec;
 136 } RECSTREAM;
 137
 138 static u_int    fix_buf_size(u_int);
 139 static bool_t   flush_out(RECSTREAM *, bool_t);
 140 static bool_t   fill_input_buf(RECSTREAM *);
 141 static bool_t   get_input_bytes(RECSTREAM *, char *, int);
 142 static bool_t   set_input_fragment(RECSTREAM *);
 143 static bool_t   skip_input_bytes(RECSTREAM *, long);
 144 static bool_t   realloc_stream(RECSTREAM *, int);
 145
 146
 147 /*
 148  * Create an xdr handle for xdrrec
 149  * xdrrec_create fills in xdrs.  Sendsize and recvsize are
 150  * send and recv buffer sizes (0 => use default).
 151  * tcp_handle is an opaque handle that is passed as the first parameter to
 152  * the procedures readit and writeit.  Readit and writeit are read and
 153  * write respectively.   They are like the system
 154  * calls expect that they take an opaque handle rather than an fd.
 155  */
 156 void
 157 xdrrec_create(xdrs, sendsize, recvsize, tcp_handle, readit, writeit)
 158         XDR *xdrs;
 159         u_int sendsize;
 160         u_int recvsize;
 161         void *tcp_handle;
 162         /* like read, but pass it a tcp_handle, not sock */
 163         int (*readit)(void *, void *, int);
 164         /* like write, but pass it a tcp_handle, not sock */
 165         int (*writeit)(void *, void *, int);
 166 {
 167         RECSTREAM *rstrm = mem_alloc(sizeof(RECSTREAM));
 168
 169         if (rstrm == NULL) {
 170                 warnx("xdrrec_create: out of memory");
 171                 /*
 172                  *  This is bad.  Should rework xdrrec_create to
 173                  *  return a handle, and in this case return NULL
 174                  */
 175                 return;
 176         }
 177         rstrm->sendsize = sendsize = fix_buf_size(sendsize);
 178         rstrm->out_base = mem_alloc(rstrm->sendsize);
 179         if (rstrm->out_base == NULL) {
 180                 warnx("xdrrec_create: out of memory");
 181                 mem_free(rstrm, sizeof(RECSTREAM));
 182                 return;
 183         }
 184         rstrm->recvsize = recvsize = fix_buf_size(recvsize);
 185         rstrm->in_base = mem_alloc(recvsize);
 186         if (rstrm->in_base == NULL) {
 187                 warnx("xdrrec_create: out of memory");
 188                 mem_free(rstrm->out_base, sendsize);
 189                 mem_free(rstrm, sizeof(RECSTREAM));
 190                 return;
 191         }
 192         /*
 193          * now the rest ...
 194          */
 195         xdrs->x_ops = &xdrrec_ops;
 196         xdrs->x_private = rstrm;
 197         rstrm->tcp_handle = tcp_handle;
 198         rstrm->readit = readit;
 199         rstrm->writeit = writeit;
 200         rstrm->out_finger = rstrm->out_boundry = rstrm->out_base;
 201         rstrm->frag_header = (u_int32_t *)(void *)rstrm->out_base;
 202         rstrm->out_finger += sizeof(u_int32_t);
 203         rstrm->out_boundry += sendsize;
 204         rstrm->frag_sent = FALSE;
 205         rstrm->in_size = recvsize;
 206         rstrm->in_boundry = rstrm->in_base;
 207         rstrm->in_finger = (rstrm->in_boundry += recvsize);
 208         rstrm->fbtbc = 0;
 209         rstrm->last_frag = TRUE;
 210         rstrm->in_haveheader = FALSE;
 211         rstrm->in_hdrlen = 0;
 212         rstrm->in_hdrp = (char *)(void *)&rstrm->in_header;
 213         rstrm->nonblock = FALSE;
 214         rstrm->in_reclen = 0;
 215         rstrm->in_received = 0;
 216 }
 217
 218
 219 /*
 220  * The reoutines defined below are the xdr ops which will go into the
 221  * xdr handle filled in by xdrrec_create.
 222  */
 223
 224 static bool_t
 225 xdrrec_getlong(xdrs, lp)
 226         XDR *xdrs;
 227         long *lp;
 228 {
 229         RECSTREAM *rstrm = (RECSTREAM *)(xdrs->x_private);
 230         int32_t *buflp = (int32_t *)(void *)(rstrm->in_finger);
 231         int32_t mylong;
 232
 233         /* first try the inline, fast case */
 234         if ((rstrm->fbtbc >= sizeof(int32_t)) &&
 235                 (((long)rstrm->in_boundry - (long)buflp) >= sizeof(int32_t))) {
 236                 *lp = (long)ntohl((u_int32_t)(*buflp));
 237                 rstrm->fbtbc -= sizeof(int32_t);
 238                 rstrm->in_finger += sizeof(int32_t);
 239         } else {
 240                 if (! xdrrec_getbytes(xdrs, (char *)(void *)&mylong,
 241                     sizeof(int32_t)))
 242                         return (FALSE);
 243                 *lp = (long)ntohl((u_int32_t)mylong);
 244         }
 245         return (TRUE);
 246 }
 247
 248 static bool_t
 249 xdrrec_putlong(xdrs, lp)
 250         XDR *xdrs;
 251         const long *lp;
 252 {
 253         RECSTREAM *rstrm = (RECSTREAM *)(xdrs->x_private);
 254         int32_t *dest_lp = ((int32_t *)(void *)(rstrm->out_finger));
 255
 256         if ((rstrm->out_finger += sizeof(int32_t)) > rstrm->out_boundry) {
 257                 /*
 258                  * this case should almost never happen so the code is
 259                  * inefficient
 260                  */
 261                 rstrm->out_finger -= sizeof(int32_t);
 262                 rstrm->frag_sent = TRUE;
 263                 if (! flush_out(rstrm, FALSE))
 264                         return (FALSE);
 265                 dest_lp = ((int32_t *)(void *)(rstrm->out_finger));
 266                 rstrm->out_finger += sizeof(int32_t);
 267         }
 268         *dest_lp = (int32_t)htonl((u_int32_t)(*lp));
 269         return (TRUE);
 270 }
 271
 272 static bool_t  /* must manage buffers, fragments, and records */
 273 xdrrec_getbytes(xdrs, addr, len)
 274         XDR *xdrs;
 275         char *addr;
 276         u_int len;
 277 {
 278         RECSTREAM *rstrm = (RECSTREAM *)(xdrs->x_private);
 279         int current;
 280
 281         while (len > 0) {
 282                 current = (int)rstrm->fbtbc;
 283                 if (current == 0) {
 284                         if (rstrm->last_frag)
 285                                 return (FALSE);
 286                         if (! set_input_fragment(rstrm))
 287                                 return (FALSE);
 288                         continue;
 289                 }
 290                 current = (len < current) ? len : current;
 291                 if (! get_input_bytes(rstrm, addr, current))
 292                         return (FALSE);
 293                 addr += current;
 294                 rstrm->fbtbc -= current;
 295                 len -= current;
 296         }
 297         return (TRUE);
 298 }
 299
 300 static bool_t
 301 xdrrec_putbytes(xdrs, addr, len)
 302         XDR *xdrs;
 303         const char *addr;
 304         u_int len;
 305 {
 306         RECSTREAM *rstrm = (RECSTREAM *)(xdrs->x_private);
 307         size_t current;
 308
 309         while (len > 0) {
 310                 current = (size_t)((u_long)rstrm->out_boundry -
 311                     (u_long)rstrm->out_finger);
 312                 current = (len < current) ? len : current;
 313                 memmove(rstrm->out_finger, addr, current);
 314                 rstrm->out_finger += current;
 315                 addr += current;
 316                 len -= current;
 317                 if (rstrm->out_finger == rstrm->out_boundry) {
 318                         rstrm->frag_sent = TRUE;
 319                         if (! flush_out(rstrm, FALSE))
 320                                 return (FALSE);
 321                 }
 322         }
 323         return (TRUE);
 324 }
 325
 326 static u_int
 327 xdrrec_getpos(xdrs)
 328         XDR *xdrs;
 329 {
 330         RECSTREAM *rstrm = (RECSTREAM *)xdrs->x_private;
 331         off_t pos;
 332
 333         pos = lseek((int)(u_long)rstrm->tcp_handle, (off_t)0, 1);
 334         if (pos != -1)
 335                 switch (xdrs->x_op) {
 336
 337                 case XDR_ENCODE:
 338                         pos += rstrm->out_finger - rstrm->out_base;
 339                         break;
 340
 341                 case XDR_DECODE:
 342                         pos -= rstrm->in_boundry - rstrm->in_finger;
 343                         break;
 344
 345                 default:
 346                         pos = (off_t) -1;
 347                         break;
 348                 }
 349         return ((u_int) pos);
 350 }
 351
 352 static bool_t
 353 xdrrec_setpos(xdrs, pos)
 354         XDR *xdrs;
 355         u_int pos;
 356 {
 357         RECSTREAM *rstrm = (RECSTREAM *)xdrs->x_private;
 358         u_int currpos = xdrrec_getpos(xdrs);
 359         int delta = currpos - pos;
 360         char *newpos;
 361
 362         if ((int)currpos != -1)
 363                 switch (xdrs->x_op) {
 364
 365                 case XDR_ENCODE:
 366                         newpos = rstrm->out_finger - delta;
 367                         if ((newpos > (char *)(void *)(rstrm->frag_header)) &&
 368                                 (newpos < rstrm->out_boundry)) {
 369                                 rstrm->out_finger = newpos;
 370                                 return (TRUE);
 371                         }
 372                         break;
 373
 374                 case XDR_DECODE:
 375                         newpos = rstrm->in_finger - delta;
 376                         if ((delta < (int)(rstrm->fbtbc)) &&
 377                                 (newpos <= rstrm->in_boundry) &&
 378                                 (newpos >= rstrm->in_base)) {
 379                                 rstrm->in_finger = newpos;
 380                                 rstrm->fbtbc -= delta;
 381                                 return (TRUE);
 382                         }
 383                         break;
 384
 385                 case XDR_FREE:
 386                         break;
 387                 }
 388         return (FALSE);
 389 }
 390
 391 static int32_t *
 392 xdrrec_inline(xdrs, len)
 393         XDR *xdrs;
 394         u_int len;
 395 {
 396         RECSTREAM *rstrm = (RECSTREAM *)xdrs->x_private;
 397         int32_t *buf = NULL;
 398
 399         switch (xdrs->x_op) {
 400
 401         case XDR_ENCODE:
 402                 if ((rstrm->out_finger + len) <= rstrm->out_boundry) {
 403                         buf = (int32_t *)(void *)rstrm->out_finger;
 404                         rstrm->out_finger += len;
 405                 }
 406                 break;
 407
 408         case XDR_DECODE:
 409                 if ((len <= rstrm->fbtbc) &&
 410                         ((rstrm->in_finger + len) <= rstrm->in_boundry)) {
 411                         buf = (int32_t *)(void *)rstrm->in_finger;
 412                         rstrm->fbtbc -= len;
 413                         rstrm->in_finger += len;
 414                 }
 415                 break;
 416
 417         case XDR_FREE:
 418                 break;
 419         }
 420         return (buf);
 421 }
 422
 423 static void
 424 xdrrec_destroy(xdrs)
 425         XDR *xdrs;
 426 {
 427         RECSTREAM *rstrm = (RECSTREAM *)xdrs->x_private;
 428
 429         mem_free(rstrm->out_base, rstrm->sendsize);
 430         mem_free(rstrm->in_base, rstrm->recvsize);
 431         mem_free(rstrm, sizeof(RECSTREAM));
 432 }
 433
 434
 435 /*
 436  * Exported routines to manage xdr records
 437  */
 438
 439 /*
 440  * Before reading (deserializing from the stream, one should always call
 441  * this procedure to guarantee proper record alignment.
 442  */
 443 bool_t
 444 xdrrec_skiprecord(xdrs)
 445         XDR *xdrs;
 446 {
 447         RECSTREAM *rstrm = (RECSTREAM *)(xdrs->x_private);
 448         enum xprt_stat xstat;
 449
 450         if (rstrm->nonblock) {
 451                 if (__xdrrec_getrec(xdrs, &xstat, FALSE)) {
 452                         rstrm->fbtbc = 0;
 453                         return TRUE;
 454                 }
 455                 if (rstrm->in_finger == rstrm->in_boundry &&
 456                     xstat == XPRT_MOREREQS) {
 457                         rstrm->fbtbc = 0;
 458                         return TRUE;
 459                 }
 460                 return FALSE;
 461         }
 462
 463         while (rstrm->fbtbc > 0 || (! rstrm->last_frag)) {
 464                 if (! skip_input_bytes(rstrm, rstrm->fbtbc))
 465                         return (FALSE);
 466                 rstrm->fbtbc = 0;
 467                 if ((! rstrm->last_frag) && (! set_input_fragment(rstrm)))
 468                         return (FALSE);
 469         }
 470         rstrm->last_frag = FALSE;
 471         return (TRUE);
 472 }
 473
 474 /*
 475  * Look ahead function.
 476  * Returns TRUE iff there is no more input in the buffer
 477  * after consuming the rest of the current record.
 478  */
 479 bool_t
 480 xdrrec_eof(xdrs)
 481         XDR *xdrs;
 482 {
 483         RECSTREAM *rstrm = (RECSTREAM *)(xdrs->x_private);
 484
 485         while (rstrm->fbtbc > 0 || (! rstrm->last_frag)) {
 486                 if (! skip_input_bytes(rstrm, rstrm->fbtbc))
 487                         return (TRUE);
 488                 rstrm->fbtbc = 0;
 489                 if ((! rstrm->last_frag) && (! set_input_fragment(rstrm)))
 490                         return (TRUE);
 491         }
 492         if (rstrm->in_finger == rstrm->in_boundry)
 493                 return (TRUE);
 494         return (FALSE);
 495 }
 496
 497 /*
 498  * The client must tell the package when an end-of-record has occurred.
 499  * The second paraemters tells whether the record should be flushed to the
 500  * (output) tcp stream.  (This let's the package support batched or
 501  * pipelined procedure calls.)  TRUE => immmediate flush to tcp connection.
 502  */
 503 bool_t
 504 xdrrec_endofrecord(xdrs, sendnow)
 505         XDR *xdrs;
 506         bool_t sendnow;
 507 {
 508         RECSTREAM *rstrm = (RECSTREAM *)(xdrs->x_private);
 509         u_long len;  /* fragment length */
 510
 511         if (sendnow || rstrm->frag_sent ||
 512                 ((u_long)rstrm->out_finger + sizeof(u_int32_t) >=
 513                 (u_long)rstrm->out_boundry)) {
 514                 rstrm->frag_sent = FALSE;
 515                 return (flush_out(rstrm, TRUE));
 516         }
 517         len = (u_long)(rstrm->out_finger) - (u_long)(rstrm->frag_header) -
 518            sizeof(u_int32_t);
 519         *(rstrm->frag_header) = htonl((u_int32_t)len | LAST_FRAG);
 520         rstrm->frag_header = (u_int32_t *)(void *)rstrm->out_finger;
 521         rstrm->out_finger += sizeof(u_int32_t);
 522         return (TRUE);
 523 }
 524
 525 /*
 526  * Fill the stream buffer with a record for a non-blocking connection.
 527  * Return true if a record is available in the buffer, false if not.
 528  */
 529 bool_t
 530 __xdrrec_getrec(xdrs, statp, expectdata)
 531         XDR *xdrs;
 532         enum xprt_stat *statp;
 533         bool_t expectdata;
 534 {
 535         RECSTREAM *rstrm = (RECSTREAM *)(xdrs->x_private);
 536         ssize_t n;
 537         int fraglen;
 538
 539         if (!rstrm->in_haveheader) {
 540                 n = rstrm->readit(rstrm->tcp_handle, rstrm->in_hdrp,
 541                     (int)sizeof (rstrm->in_header) - rstrm->in_hdrlen);
 542                 if (n == 0) {
 543                         *statp = expectdata ? XPRT_DIED : XPRT_IDLE;
 544                         return FALSE;
 545                 }
 546                 if (n < 0) {
 547                         *statp = XPRT_DIED;
 548                         return FALSE;
 549                 }
 550                 rstrm->in_hdrp += n;
 551                 rstrm->in_hdrlen += n;
 552                 if (rstrm->in_hdrlen < sizeof (rstrm->in_header)) {
 553                         *statp = XPRT_MOREREQS;
 554                         return FALSE;
 555                 }
 556                 rstrm->in_header = ntohl(rstrm->in_header);
 557                 fraglen = (int)(rstrm->in_header & ~LAST_FRAG);
 558                 if (fraglen == 0 || fraglen > rstrm->in_maxrec ||
 559                     (rstrm->in_reclen + fraglen) > rstrm->in_maxrec) {
 560                         *statp = XPRT_DIED;
 561                         return FALSE;
 562                 }
 563                 rstrm->in_reclen += fraglen;
 564                 if (rstrm->in_reclen > rstrm->recvsize)
 565                         realloc_stream(rstrm, rstrm->in_reclen);
 566                 if (rstrm->in_header & LAST_FRAG) {
 567                         rstrm->in_header &= ~LAST_FRAG;
 568                         rstrm->last_frag = TRUE;
 569                 }
 570         }
 571
 572         n =  rstrm->readit(rstrm->tcp_handle,
 573             rstrm->in_base + rstrm->in_received,
 574             (rstrm->in_reclen - rstrm->in_received));
 575
 576         if (n < 0) {
 577                 *statp = XPRT_DIED;
 578                 return FALSE;
 579         }
 580
 581         if (n == 0) {
 582                 *statp = expectdata ? XPRT_DIED : XPRT_IDLE;
 583                 return FALSE;
 584         }
 585
 586         rstrm->in_received += n;
 587
 588         if (rstrm->in_received == rstrm->in_reclen) {
 589                 rstrm->in_haveheader = FALSE;
 590                 rstrm->in_hdrp = (char *)(void *)&rstrm->in_header;
 591                 rstrm->in_hdrlen = 0;
 592                 if (rstrm->last_frag) {
 593                         rstrm->fbtbc = rstrm->in_reclen;
 594                         rstrm->in_boundry = rstrm->in_base + rstrm->in_reclen;
 595                         rstrm->in_finger = rstrm->in_base;
 596                         rstrm->in_reclen = rstrm->in_received = 0;
 597                         *statp = XPRT_MOREREQS;
 598                         return TRUE;
 599                 }
 600         }
 601
 602         *statp = XPRT_MOREREQS;
 603         return FALSE;
 604 }
 605
 606 bool_t
 607 __xdrrec_setnonblock(xdrs, maxrec)
 608         XDR *xdrs;
 609         int maxrec;
 610 {
 611         RECSTREAM *rstrm = (RECSTREAM *)(xdrs->x_private);
 612
 613         rstrm->nonblock = TRUE;
 614         if (maxrec == 0)
 615                 maxrec = rstrm->recvsize;
 616         rstrm->in_maxrec = maxrec;
 617         return TRUE;
 618 }
 619
 620 /*
 621  * Internal useful routines
 622  */
 623 static bool_t
 624 flush_out(rstrm, eor)
 625         RECSTREAM *rstrm;
 626         bool_t eor;
 627 {
 628         u_int32_t eormask = (eor == TRUE) ? LAST_FRAG : 0;
 629         u_int32_t len = (u_int32_t)((u_long)(rstrm->out_finger) -
 630                 (u_long)(rstrm->frag_header) - sizeof(u_int32_t));
 631
 632         *(rstrm->frag_header) = htonl(len | eormask);
 633         len = (u_int32_t)((u_long)(rstrm->out_finger) -
 634             (u_long)(rstrm->out_base));
 635         if ((*(rstrm->writeit))(rstrm->tcp_handle, rstrm->out_base, (int)len)
 636                 != (int)len)
 637                 return (FALSE);
 638         rstrm->frag_header = (u_int32_t *)(void *)rstrm->out_base;
 639         rstrm->out_finger = (char *)rstrm->out_base + sizeof(u_int32_t);
 640         return (TRUE);
 641 }
 642
 643 static bool_t  /* knows nothing about records!  Only about input buffers */
 644 fill_input_buf(rstrm)
 645         RECSTREAM *rstrm;
 646 {
 647         char *where;
 648         u_int32_t i;
 649         int len;
 650
 651         if (rstrm->nonblock)
 652                 return FALSE;
 653
 654         where = rstrm->in_base;
 655         i = (u_int32_t)((u_long)rstrm->in_boundry % BYTES_PER_XDR_UNIT);
 656         where += i;
 657         len = (u_int32_t)(rstrm->in_size - i);
 658         if ((len = (*(rstrm->readit))(rstrm->tcp_handle, where, len)) == -1)
 659                 return (FALSE);
 660         rstrm->in_finger = where;
 661         where += len;
 662         rstrm->in_boundry = where;
 663         return (TRUE);
 664 }
 665
 666 static bool_t  /* knows nothing about records!  Only about input buffers */
 667 get_input_bytes(rstrm, addr, len)
 668         RECSTREAM *rstrm;
 669         char *addr;
 670         int len;
 671 {
 672         size_t current;
 673
 674         if (rstrm->nonblock) {
 675                 if (len > (int)(rstrm->in_boundry - rstrm->in_finger))
 676                         return FALSE;
 677                 memcpy(addr, rstrm->in_finger, (size_t)len);
 678                 rstrm->in_finger += len;
 679                 return TRUE;
 680         }
 681
 682         while (len > 0) {
 683                 current = (size_t)((long)rstrm->in_boundry -
 684                     (long)rstrm->in_finger);
 685                 if (current == 0) {
 686                         if (! fill_input_buf(rstrm))
 687                                 return (FALSE);
 688                         continue;
 689                 }
 690                 current = (len < current) ? len : current;
 691                 memmove(addr, rstrm->in_finger, current);
 692                 rstrm->in_finger += current;
 693                 addr += current;
 694                 len -= current;
 695         }
 696         return (TRUE);
 697 }
 698
 699 static bool_t  /* next two bytes of the input stream are treated as a header */
 700 set_input_fragment(rstrm)
 701         RECSTREAM *rstrm;
 702 {
 703         u_int32_t header;
 704
 705         if (rstrm->nonblock)
 706                 return FALSE;
 707         if (! get_input_bytes(rstrm, (char *)(void *)&header, sizeof(header)))
 708                 return (FALSE);
 709         header = ntohl(header);
 710         rstrm->last_frag = ((header & LAST_FRAG) == 0) ? FALSE : TRUE;
 711         /*
 712          * Sanity check. Try not to accept wildly incorrect
 713          * record sizes. Unfortunately, the only record size
 714          * we can positively identify as being 'wildly incorrect'
 715          * is zero. Ridiculously large record sizes may look wrong,
 716          * but we don't have any way to be certain that they aren't
 717          * what the client actually intended to send us.
 718          */
 719         if (header == 0)
 720                 return(FALSE);
 721         rstrm->fbtbc = header & (~LAST_FRAG);
 722         return (TRUE);
 723 }
 724
 725 static bool_t  /* consumes input bytes; knows nothing about records! */
 726 skip_input_bytes(rstrm, cnt)
 727         RECSTREAM *rstrm;
 728         long cnt;
 729 {
 730         u_int32_t current;
 731
 732         while (cnt > 0) {
 733                 current = (size_t)((long)rstrm->in_boundry -
 734                     (long)rstrm->in_finger);
 735                 if (current == 0) {
 736                         if (! fill_input_buf(rstrm))
 737                                 return (FALSE);
 738                         continue;
 739                 }
 740                 current = (u_int32_t)((cnt < current) ? cnt : current);
 741                 rstrm->in_finger += current;
 742                 cnt -= current;
 743         }
 744         return (TRUE);
 745 }
 746
 747 static u_int
 748 fix_buf_size(s)
 749         u_int s;
 750 {
 751
 752         if (s < 100)
 753                 s = 4000;
 754         return (RNDUP(s));
 755 }
 756
 757 /*
 758  * Reallocate the input buffer for a non-block stream.
 759  */
 760 static bool_t
 761 realloc_stream(rstrm, size)
 762         RECSTREAM *rstrm;
 763         int size;
 764 {
 765         ptrdiff_t diff;
 766         char *buf;
 767
 768         if (size > rstrm->recvsize) {
 769                 buf = realloc(rstrm->in_base, (size_t)size);
 770                 if (buf == NULL)
 771                         return FALSE;
 772                 diff = buf - rstrm->in_base;
 773                 rstrm->in_finger += diff;
 774                 rstrm->in_base = buf;
 775                 rstrm->in_boundry = buf + size;
 776                 rstrm->recvsize = size;
 777                 rstrm->in_size = size;
 778         }
 779
 780         return TRUE;
 781 }