crypto/bio/bss_bio.c

   1 /* ====================================================================
   2  * Copyright (c) 1998-2003 The OpenSSL Project.  All rights reserved.
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions
   6  * are met:
   7  *
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  *
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in
  13  *    the documentation and/or other materials provided with the
  14  *    distribution.
  15  *
  16  * 3. All advertising materials mentioning features or use of this
  17  *    software must display the following acknowledgment:
  18  *    "This product includes software developed by the OpenSSL Project
  19  *    for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
  20  *
  21  * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
  22  *    endorse or promote products derived from this software without
  23  *    prior written permission. For written permission, please contact
  24  *    openssl-core@openssl.org.
  25  *
  26  * 5. Products derived from this software may not be called "OpenSSL"
  27  *    nor may "OpenSSL" appear in their names without prior written
  28  *    permission of the OpenSSL Project.
  29  *
  30  * 6. Redistributions of any form whatsoever must retain the following
  31  *    acknowledgment:
  32  *    "This product includes software developed by the OpenSSL Project
  33  *    for use in the OpenSSL Toolkit (http://www.openssl.org/)"
  34  *
  35  * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
  36  * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  37  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  38  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
  39  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  40  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  41  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  42  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  43  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  44  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  45  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
  46  * OF THE POSSIBILITY OF SUCH DAMAGE.
  47  * ====================================================================
  48  *
  49  * This product includes cryptographic software written by Eric Young
  50  * (eay@cryptsoft.com).  This product includes software written by Tim
  51  * Hudson (tjh@cryptsoft.com).
  52  *
  53  */
  54
  55 /*
  56  * Special method for a BIO where the other endpoint is also a BIO of this
  57  * kind, handled by the same thread (i.e. the "peer" is actually ourselves,
  58  * wearing a different hat). Such "BIO pairs" are mainly for using the SSL
  59  * library with I/O interfaces for which no specific BIO method is available.
  60  * See ssl/ssltest.c for some hints on how this can be used.
  61  */
  62
  63 /* BIO_DEBUG implies BIO_PAIR_DEBUG */
  64 #ifdef BIO_DEBUG
  65 # ifndef BIO_PAIR_DEBUG
  66 #  define BIO_PAIR_DEBUG
  67 # endif
  68 #endif
  69
  70 /* disable assert() unless BIO_PAIR_DEBUG has been defined */
  71 #ifndef BIO_PAIR_DEBUG
  72 # ifndef NDEBUG
  73 #  define NDEBUG
  74 # endif
  75 #endif
  76
  77 #include <assert.h>
  78 #include <limits.h>
  79 #include <stdlib.h>
  80 #include <string.h>
  81
  82 #include <openssl/bio.h>
  83 #include <openssl/err.h>
  84 #include <openssl/crypto.h>
  85
  86 #include "e_os.h"
  87
  88 /* VxWorks defines SSIZE_MAX with an empty value causing compile errors */
  89 #if defined(OPENSSL_SYS_VXWORKS)
  90 # undef SSIZE_MAX
  91 #endif
  92 #ifndef SSIZE_MAX
  93 # define SSIZE_MAX INT_MAX
  94 #endif
  95
  96 static int bio_new(BIO *bio);
  97 static int bio_free(BIO *bio);
  98 static int bio_read(BIO *bio, char *buf, int size);
  99 static int bio_write(BIO *bio, const char *buf, int num);
 100 static long bio_ctrl(BIO *bio, int cmd, long num, void *ptr);
 101 static int bio_puts(BIO *bio, const char *str);
 102
 103 static int bio_make_pair(BIO *bio1, BIO *bio2);
 104 static void bio_destroy_pair(BIO *bio);
 105
 106 static BIO_METHOD methods_biop = {
 107     BIO_TYPE_BIO,
 108     "BIO pair",
 109     bio_write,
 110     bio_read,
 111     bio_puts,
 112     NULL /* no bio_gets */ ,
 113     bio_ctrl,
 114     bio_new,
 115     bio_free,
 116     NULL                        /* no bio_callback_ctrl */
 117 };
 118
 119 BIO_METHOD *BIO_s_bio(void)
 120 {
 121     return &methods_biop;
 122 }
 123
 124 struct bio_bio_st {
 125     BIO *peer;                  /* NULL if buf == NULL. If peer != NULL, then
 126                                  * peer->ptr is also a bio_bio_st, and its
 127                                  * "peer" member points back to us. peer !=
 128                                  * NULL iff init != 0 in the BIO. */
 129     /* This is for what we write (i.e. reading uses peer's struct): */
 130     int closed;                 /* valid iff peer != NULL */
 131     size_t len;                 /* valid iff buf != NULL; 0 if peer == NULL */
 132     size_t offset;              /* valid iff buf != NULL; 0 if len == 0 */
 133     size_t size;
 134     char *buf;                  /* "size" elements (if != NULL) */
 135     size_t request;             /* valid iff peer != NULL; 0 if len != 0,
 136                                  * otherwise set by peer to number of bytes
 137                                  * it (unsuccessfully) tried to read, never
 138                                  * more than buffer space (size-len)
 139                                  * warrants. */
 140 };
 141
 142 static int bio_new(BIO *bio)
 143 {
 144     struct bio_bio_st *b;
 145
 146     b = OPENSSL_malloc(sizeof(*b));
 147     if (b == NULL)
 148         return 0;
 149
 150     b->peer = NULL;
 151     /* enough for one TLS record (just a default) */
 152     b->size = 17 * 1024;
 153     b->buf = NULL;
 154
 155     bio->ptr = b;
 156     return 1;
 157 }
 158
 159 static int bio_free(BIO *bio)
 160 {
 161     struct bio_bio_st *b;
 162
 163     if (bio == NULL)
 164         return 0;
 165     b = bio->ptr;
 166
 167     assert(b != NULL);
 168
 169     if (b->peer)
 170         bio_destroy_pair(bio);
 171
 172     OPENSSL_free(b->buf);
 173     OPENSSL_free(b);
 174
 175     return 1;
 176 }
 177
 178 static int bio_read(BIO *bio, char *buf, int size_)
 179 {
 180     size_t size = size_;
 181     size_t rest;
 182     struct bio_bio_st *b, *peer_b;
 183
 184     BIO_clear_retry_flags(bio);
 185
 186     if (!bio->init)
 187         return 0;
 188
 189     b = bio->ptr;
 190     assert(b != NULL);
 191     assert(b->peer != NULL);
 192     peer_b = b->peer->ptr;
 193     assert(peer_b != NULL);
 194     assert(peer_b->buf != NULL);
 195
 196     peer_b->request = 0;        /* will be set in "retry_read" situation */
 197
 198     if (buf == NULL || size == 0)
 199         return 0;
 200
 201     if (peer_b->len == 0) {
 202         if (peer_b->closed)
 203             return 0;           /* writer has closed, and no data is left */
 204         else {
 205             BIO_set_retry_read(bio); /* buffer is empty */
 206             if (size <= peer_b->size)
 207                 peer_b->request = size;
 208             else
 209                 /*
 210                  * don't ask for more than the peer can deliver in one write
 211                  */
 212                 peer_b->request = peer_b->size;
 213             return -1;
 214         }
 215     }
 216
 217     /* we can read */
 218     if (peer_b->len < size)
 219         size = peer_b->len;
 220
 221     /* now read "size" bytes */
 222
 223     rest = size;
 224
 225     assert(rest > 0);
 226     do {                        /* one or two iterations */
 227         size_t chunk;
 228
 229         assert(rest <= peer_b->len);
 230         if (peer_b->offset + rest <= peer_b->size)
 231             chunk = rest;
 232         else
 233             /* wrap around ring buffer */
 234             chunk = peer_b->size - peer_b->offset;
 235         assert(peer_b->offset + chunk <= peer_b->size);
 236
 237         memcpy(buf, peer_b->buf + peer_b->offset, chunk);
 238
 239         peer_b->len -= chunk;
 240         if (peer_b->len) {
 241             peer_b->offset += chunk;
 242             assert(peer_b->offset <= peer_b->size);
 243             if (peer_b->offset == peer_b->size)
 244                 peer_b->offset = 0;
 245             buf += chunk;
 246         } else {
 247             /* buffer now empty, no need to advance "buf" */
 248             assert(chunk == rest);
 249             peer_b->offset = 0;
 250         }
 251         rest -= chunk;
 252     }
 253     while (rest);
 254
 255     return size;
 256 }
 257
 258 /*-
 259  * non-copying interface: provide pointer to available data in buffer
 260  *    bio_nread0:  return number of available bytes
 261  *    bio_nread:   also advance index
 262  * (example usage:  bio_nread0(), read from buffer, bio_nread()
 263  *  or just         bio_nread(), read from buffer)
 264  */
 265 /*
 266  * WARNING: The non-copying interface is largely untested as of yet and may
 267  * contain bugs.
 268  */
 269 static ossl_ssize_t bio_nread0(BIO *bio, char **buf)
 270 {
 271     struct bio_bio_st *b, *peer_b;
 272     ossl_ssize_t num;
 273
 274     BIO_clear_retry_flags(bio);
 275
 276     if (!bio->init)
 277         return 0;
 278
 279     b = bio->ptr;
 280     assert(b != NULL);
 281     assert(b->peer != NULL);
 282     peer_b = b->peer->ptr;
 283     assert(peer_b != NULL);
 284     assert(peer_b->buf != NULL);
 285
 286     peer_b->request = 0;
 287
 288     if (peer_b->len == 0) {
 289         char dummy;
 290
 291         /* avoid code duplication -- nothing available for reading */
 292         return bio_read(bio, &dummy, 1); /* returns 0 or -1 */
 293     }
 294
 295     num = peer_b->len;
 296     if (peer_b->size < peer_b->offset + num)
 297         /* no ring buffer wrap-around for non-copying interface */
 298         num = peer_b->size - peer_b->offset;
 299     assert(num > 0);
 300
 301     if (buf != NULL)
 302         *buf = peer_b->buf + peer_b->offset;
 303     return num;
 304 }
 305
 306 static ossl_ssize_t bio_nread(BIO *bio, char **buf, size_t num_)
 307 {
 308     struct bio_bio_st *b, *peer_b;
 309     ossl_ssize_t num, available;
 310
 311     if (num_ > SSIZE_MAX)
 312         num = SSIZE_MAX;
 313     else
 314         num = (ossl_ssize_t) num_;
 315
 316     available = bio_nread0(bio, buf);
 317     if (num > available)
 318         num = available;
 319     if (num <= 0)
 320         return num;
 321
 322     b = bio->ptr;
 323     peer_b = b->peer->ptr;
 324
 325     peer_b->len -= num;
 326     if (peer_b->len) {
 327         peer_b->offset += num;
 328         assert(peer_b->offset <= peer_b->size);
 329         if (peer_b->offset == peer_b->size)
 330             peer_b->offset = 0;
 331     } else
 332         peer_b->offset = 0;
 333
 334     return num;
 335 }
 336
 337 static int bio_write(BIO *bio, const char *buf, int num_)
 338 {
 339     size_t num = num_;
 340     size_t rest;
 341     struct bio_bio_st *b;
 342
 343     BIO_clear_retry_flags(bio);
 344
 345     if (!bio->init || buf == NULL || num == 0)
 346         return 0;
 347
 348     b = bio->ptr;
 349     assert(b != NULL);
 350     assert(b->peer != NULL);
 351     assert(b->buf != NULL);
 352
 353     b->request = 0;
 354     if (b->closed) {
 355         /* we already closed */
 356         BIOerr(BIO_F_BIO_WRITE, BIO_R_BROKEN_PIPE);
 357         return -1;
 358     }
 359
 360     assert(b->len <= b->size);
 361
 362     if (b->len == b->size) {
 363         BIO_set_retry_write(bio); /* buffer is full */
 364         return -1;
 365     }
 366
 367     /* we can write */
 368     if (num > b->size - b->len)
 369         num = b->size - b->len;
 370
 371     /* now write "num" bytes */
 372
 373     rest = num;
 374
 375     assert(rest > 0);
 376     do {                        /* one or two iterations */
 377         size_t write_offset;
 378         size_t chunk;
 379
 380         assert(b->len + rest <= b->size);
 381
 382         write_offset = b->offset + b->len;
 383         if (write_offset >= b->size)
 384             write_offset -= b->size;
 385         /* b->buf[write_offset] is the first byte we can write to. */
 386
 387         if (write_offset + rest <= b->size)
 388             chunk = rest;
 389         else
 390             /* wrap around ring buffer */
 391             chunk = b->size - write_offset;
 392
 393         memcpy(b->buf + write_offset, buf, chunk);
 394
 395         b->len += chunk;
 396
 397         assert(b->len <= b->size);
 398
 399         rest -= chunk;
 400         buf += chunk;
 401     }
 402     while (rest);
 403
 404     return num;
 405 }
 406
 407 /*-
 408  * non-copying interface: provide pointer to region to write to
 409  *   bio_nwrite0:  check how much space is available
 410  *   bio_nwrite:   also increase length
 411  * (example usage:  bio_nwrite0(), write to buffer, bio_nwrite()
 412  *  or just         bio_nwrite(), write to buffer)
 413  */
 414 static ossl_ssize_t bio_nwrite0(BIO *bio, char **buf)
 415 {
 416     struct bio_bio_st *b;
 417     size_t num;
 418     size_t write_offset;
 419
 420     BIO_clear_retry_flags(bio);
 421
 422     if (!bio->init)
 423         return 0;
 424
 425     b = bio->ptr;
 426     assert(b != NULL);
 427     assert(b->peer != NULL);
 428     assert(b->buf != NULL);
 429
 430     b->request = 0;
 431     if (b->closed) {
 432         BIOerr(BIO_F_BIO_NWRITE0, BIO_R_BROKEN_PIPE);
 433         return -1;
 434     }
 435
 436     assert(b->len <= b->size);
 437
 438     if (b->len == b->size) {
 439         BIO_set_retry_write(bio);
 440         return -1;
 441     }
 442
 443     num = b->size - b->len;
 444     write_offset = b->offset + b->len;
 445     if (write_offset >= b->size)
 446         write_offset -= b->size;
 447     if (write_offset + num > b->size)
 448         /*
 449          * no ring buffer wrap-around for non-copying interface (to fulfil
 450          * the promise by BIO_ctrl_get_write_guarantee, BIO_nwrite may have
 451          * to be called twice)
 452          */
 453         num = b->size - write_offset;
 454
 455     if (buf != NULL)
 456         *buf = b->buf + write_offset;
 457     assert(write_offset + num <= b->size);
 458
 459     return num;
 460 }
 461
 462 static ossl_ssize_t bio_nwrite(BIO *bio, char **buf, size_t num_)
 463 {
 464     struct bio_bio_st *b;
 465     ossl_ssize_t num, space;
 466
 467     if (num_ > SSIZE_MAX)
 468         num = SSIZE_MAX;
 469     else
 470         num = (ossl_ssize_t) num_;
 471
 472     space = bio_nwrite0(bio, buf);
 473     if (num > space)
 474         num = space;
 475     if (num <= 0)
 476         return num;
 477     b = bio->ptr;
 478     assert(b != NULL);
 479     b->len += num;
 480     assert(b->len <= b->size);
 481
 482     return num;
 483 }
 484
 485 static long bio_ctrl(BIO *bio, int cmd, long num, void *ptr)
 486 {
 487     long ret;
 488     struct bio_bio_st *b = bio->ptr;
 489
 490     assert(b != NULL);
 491
 492     switch (cmd) {
 493         /* specific CTRL codes */
 494
 495     case BIO_C_SET_WRITE_BUF_SIZE:
 496         if (b->peer) {
 497             BIOerr(BIO_F_BIO_CTRL, BIO_R_IN_USE);
 498             ret = 0;
 499         } else if (num == 0) {
 500             BIOerr(BIO_F_BIO_CTRL, BIO_R_INVALID_ARGUMENT);
 501             ret = 0;
 502         } else {
 503             size_t new_size = num;
 504
 505             if (b->size != new_size) {
 506                 OPENSSL_free(b->buf);
 507                 b->buf = NULL;
 508                 b->size = new_size;
 509             }
 510             ret = 1;
 511         }
 512         break;
 513
 514     case BIO_C_GET_WRITE_BUF_SIZE:
 515         ret = (long)b->size;
 516         break;
 517
 518     case BIO_C_MAKE_BIO_PAIR:
 519         {
 520             BIO *other_bio = ptr;
 521
 522             if (bio_make_pair(bio, other_bio))
 523                 ret = 1;
 524             else
 525                 ret = 0;
 526         }
 527         break;
 528
 529     case BIO_C_DESTROY_BIO_PAIR:
 530         /*
 531          * Affects both BIOs in the pair -- call just once! Or let
 532          * BIO_free(bio1); BIO_free(bio2); do the job.
 533          */
 534         bio_destroy_pair(bio);
 535         ret = 1;
 536         break;
 537
 538     case BIO_C_GET_WRITE_GUARANTEE:
 539         /*
 540          * How many bytes can the caller feed to the next write without
 541          * having to keep any?
 542          */
 543         if (b->peer == NULL || b->closed)
 544             ret = 0;
 545         else
 546             ret = (long)b->size - b->len;
 547         break;
 548
 549     case BIO_C_GET_READ_REQUEST:
 550         /*
 551          * If the peer unsuccessfully tried to read, how many bytes were
 552          * requested? (As with BIO_CTRL_PENDING, that number can usually be
 553          * treated as boolean.)
 554          */
 555         ret = (long)b->request;
 556         break;
 557
 558     case BIO_C_RESET_READ_REQUEST:
 559         /*
 560          * Reset request.  (Can be useful after read attempts at the other
 561          * side that are meant to be non-blocking, e.g. when probing SSL_read
 562          * to see if any data is available.)
 563          */
 564         b->request = 0;
 565         ret = 1;
 566         break;
 567
 568     case BIO_C_SHUTDOWN_WR:
 569         /* similar to shutdown(..., SHUT_WR) */
 570         b->closed = 1;
 571         ret = 1;
 572         break;
 573
 574     case BIO_C_NREAD0:
 575         /* prepare for non-copying read */
 576         ret = (long)bio_nread0(bio, ptr);
 577         break;
 578
 579     case BIO_C_NREAD:
 580         /* non-copying read */
 581         ret = (long)bio_nread(bio, ptr, (size_t)num);
 582         break;
 583
 584     case BIO_C_NWRITE0:
 585         /* prepare for non-copying write */
 586         ret = (long)bio_nwrite0(bio, ptr);
 587         break;
 588
 589     case BIO_C_NWRITE:
 590         /* non-copying write */
 591         ret = (long)bio_nwrite(bio, ptr, (size_t)num);
 592         break;
 593
 594         /* standard CTRL codes follow */
 595
 596     case BIO_CTRL_RESET:
 597         if (b->buf != NULL) {
 598             b->len = 0;
 599             b->offset = 0;
 600         }
 601         ret = 0;
 602         break;
 603
 604     case BIO_CTRL_GET_CLOSE:
 605         ret = bio->shutdown;
 606         break;
 607
 608     case BIO_CTRL_SET_CLOSE:
 609         bio->shutdown = (int)num;
 610         ret = 1;
 611         break;
 612
 613     case BIO_CTRL_PENDING:
 614         if (b->peer != NULL) {
 615             struct bio_bio_st *peer_b = b->peer->ptr;
 616
 617             ret = (long)peer_b->len;
 618         } else
 619             ret = 0;
 620         break;
 621
 622     case BIO_CTRL_WPENDING:
 623         if (b->buf != NULL)
 624             ret = (long)b->len;
 625         else
 626             ret = 0;
 627         break;
 628
 629     case BIO_CTRL_DUP:
 630         /* See BIO_dup_chain for circumstances we have to expect. */
 631         {
 632             BIO *other_bio = ptr;
 633             struct bio_bio_st *other_b;
 634
 635             assert(other_bio != NULL);
 636             other_b = other_bio->ptr;
 637             assert(other_b != NULL);
 638
 639             assert(other_b->buf == NULL); /* other_bio is always fresh */
 640
 641             other_b->size = b->size;
 642         }
 643
 644         ret = 1;
 645         break;
 646
 647     case BIO_CTRL_FLUSH:
 648         ret = 1;
 649         break;
 650
 651     case BIO_CTRL_EOF:
 652         {
 653             BIO *other_bio = ptr;
 654
 655             if (other_bio) {
 656                 struct bio_bio_st *other_b = other_bio->ptr;
 657
 658                 assert(other_b != NULL);
 659                 ret = other_b->len == 0 && other_b->closed;
 660             } else
 661                 ret = 1;
 662         }
 663         break;
 664
 665     default:
 666         ret = 0;
 667     }
 668     return ret;
 669 }
 670
 671 static int bio_puts(BIO *bio, const char *str)
 672 {
 673     return bio_write(bio, str, strlen(str));
 674 }
 675
 676 static int bio_make_pair(BIO *bio1, BIO *bio2)
 677 {
 678     struct bio_bio_st *b1, *b2;
 679
 680     assert(bio1 != NULL);
 681     assert(bio2 != NULL);
 682
 683     b1 = bio1->ptr;
 684     b2 = bio2->ptr;
 685
 686     if (b1->peer != NULL || b2->peer != NULL) {
 687         BIOerr(BIO_F_BIO_MAKE_PAIR, BIO_R_IN_USE);
 688         return 0;
 689     }
 690
 691     if (b1->buf == NULL) {
 692         b1->buf = OPENSSL_malloc(b1->size);
 693         if (b1->buf == NULL) {
 694             BIOerr(BIO_F_BIO_MAKE_PAIR, ERR_R_MALLOC_FAILURE);
 695             return 0;
 696         }
 697         b1->len = 0;
 698         b1->offset = 0;
 699     }
 700
 701     if (b2->buf == NULL) {
 702         b2->buf = OPENSSL_malloc(b2->size);
 703         if (b2->buf == NULL) {
 704             BIOerr(BIO_F_BIO_MAKE_PAIR, ERR_R_MALLOC_FAILURE);
 705             return 0;
 706         }
 707         b2->len = 0;
 708         b2->offset = 0;
 709     }
 710
 711     b1->peer = bio2;
 712     b1->closed = 0;
 713     b1->request = 0;
 714     b2->peer = bio1;
 715     b2->closed = 0;
 716     b2->request = 0;
 717
 718     bio1->init = 1;
 719     bio2->init = 1;
 720
 721     return 1;
 722 }
 723
 724 static void bio_destroy_pair(BIO *bio)
 725 {
 726     struct bio_bio_st *b = bio->ptr;
 727
 728     if (b != NULL) {
 729         BIO *peer_bio = b->peer;
 730
 731         if (peer_bio != NULL) {
 732             struct bio_bio_st *peer_b = peer_bio->ptr;
 733
 734             assert(peer_b != NULL);
 735             assert(peer_b->peer == bio);
 736
 737             peer_b->peer = NULL;
 738             peer_bio->init = 0;
 739             assert(peer_b->buf != NULL);
 740             peer_b->len = 0;
 741             peer_b->offset = 0;
 742
 743             b->peer = NULL;
 744             bio->init = 0;
 745             assert(b->buf != NULL);
 746             b->len = 0;
 747             b->offset = 0;
 748         }
 749     }
 750 }
 751
 752 /* Exported convenience functions */
 753 int BIO_new_bio_pair(BIO **bio1_p, size_t writebuf1,
 754                      BIO **bio2_p, size_t writebuf2)
 755 {
 756     BIO *bio1 = NULL, *bio2 = NULL;
 757     long r;
 758     int ret = 0;
 759
 760     bio1 = BIO_new(BIO_s_bio());
 761     if (bio1 == NULL)
 762         goto err;
 763     bio2 = BIO_new(BIO_s_bio());
 764     if (bio2 == NULL)
 765         goto err;
 766
 767     if (writebuf1) {
 768         r = BIO_set_write_buf_size(bio1, writebuf1);
 769         if (!r)
 770             goto err;
 771     }
 772     if (writebuf2) {
 773         r = BIO_set_write_buf_size(bio2, writebuf2);
 774         if (!r)
 775             goto err;
 776     }
 777
 778     r = BIO_make_bio_pair(bio1, bio2);
 779     if (!r)
 780         goto err;
 781     ret = 1;
 782
 783  err:
 784     if (ret == 0) {
 785         BIO_free(bio1);
 786         bio1 = NULL;
 787         BIO_free(bio2);
 788         bio2 = NULL;
 789     }
 790
 791     *bio1_p = bio1;
 792     *bio2_p = bio2;
 793     return ret;
 794 }
 795
 796 size_t BIO_ctrl_get_write_guarantee(BIO *bio)
 797 {
 798     return BIO_ctrl(bio, BIO_C_GET_WRITE_GUARANTEE, 0, NULL);
 799 }
 800
 801 size_t BIO_ctrl_get_read_request(BIO *bio)
 802 {
 803     return BIO_ctrl(bio, BIO_C_GET_READ_REQUEST, 0, NULL);
 804 }
 805
 806 int BIO_ctrl_reset_read_request(BIO *bio)
 807 {
 808     return (BIO_ctrl(bio, BIO_C_RESET_READ_REQUEST, 0, NULL) != 0);
 809 }
 810
 811 /*
 812  * BIO_nread0/nread/nwrite0/nwrite are available only for BIO pairs for now
 813  * (conceivably some other BIOs could allow non-copying reads and writes
 814  * too.)
 815  */
 816 int BIO_nread0(BIO *bio, char **buf)
 817 {
 818     long ret;
 819
 820     if (!bio->init) {
 821         BIOerr(BIO_F_BIO_NREAD0, BIO_R_UNINITIALIZED);
 822         return -2;
 823     }
 824
 825     ret = BIO_ctrl(bio, BIO_C_NREAD0, 0, buf);
 826     if (ret > INT_MAX)
 827         return INT_MAX;
 828     else
 829         return (int)ret;
 830 }
 831
 832 int BIO_nread(BIO *bio, char **buf, int num)
 833 {
 834     int ret;
 835
 836     if (!bio->init) {
 837         BIOerr(BIO_F_BIO_NREAD, BIO_R_UNINITIALIZED);
 838         return -2;
 839     }
 840
 841     ret = (int)BIO_ctrl(bio, BIO_C_NREAD, num, buf);
 842     if (ret > 0)
 843         bio->num_read += ret;
 844     return ret;
 845 }
 846
 847 int BIO_nwrite0(BIO *bio, char **buf)
 848 {
 849     long ret;
 850
 851     if (!bio->init) {
 852         BIOerr(BIO_F_BIO_NWRITE0, BIO_R_UNINITIALIZED);
 853         return -2;
 854     }
 855
 856     ret = BIO_ctrl(bio, BIO_C_NWRITE0, 0, buf);
 857     if (ret > INT_MAX)
 858         return INT_MAX;
 859     else
 860         return (int)ret;
 861 }
 862
 863 int BIO_nwrite(BIO *bio, char **buf, int num)
 864 {
 865     int ret;
 866
 867     if (!bio->init) {
 868         BIOerr(BIO_F_BIO_NWRITE, BIO_R_UNINITIALIZED);
 869         return -2;
 870     }
 871
 872     ret = BIO_ctrl(bio, BIO_C_NWRITE, num, buf);
 873     if (ret > 0)
 874         bio->num_write += ret;
 875     return ret;
 876 }