bss_bio.c revision 331638 
1/* crypto/bio/bss_bio.c  */
2/* ====================================================================
3 * Copyright (c) 1998-2003 The OpenSSL Project.  All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 *
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 *
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in
14 *    the documentation and/or other materials provided with the
15 *    distribution.
16 *
17 * 3. All advertising materials mentioning features or use of this
18 *    software must display the following acknowledgment:
19 *    "This product includes software developed by the OpenSSL Project
20 *    for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
21 *
22 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
23 *    endorse or promote products derived from this software without
24 *    prior written permission. For written permission, please contact
25 *    openssl-core@openssl.org.
26 *
27 * 5. Products derived from this software may not be called "OpenSSL"
28 *    nor may "OpenSSL" appear in their names without prior written
29 *    permission of the OpenSSL Project.
30 *
31 * 6. Redistributions of any form whatsoever must retain the following
32 *    acknowledgment:
33 *    "This product includes software developed by the OpenSSL Project
34 *    for use in the OpenSSL Toolkit (http://www.openssl.org/)"
35 *
36 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
37 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
38 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
39 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
40 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
41 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
42 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
43 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
44 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
45 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
46 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
47 * OF THE POSSIBILITY OF SUCH DAMAGE.
48 * ====================================================================
49 *
50 * This product includes cryptographic software written by Eric Young
51 * (eay@cryptsoft.com).  This product includes software written by Tim
52 * Hudson (tjh@cryptsoft.com).
53 *
54 */
55
56/*
57 * Special method for a BIO where the other endpoint is also a BIO of this
58 * kind, handled by the same thread (i.e. the "peer" is actually ourselves,
59 * wearing a different hat). Such "BIO pairs" are mainly for using the SSL
60 * library with I/O interfaces for which no specific BIO method is available.
61 * See ssl/ssltest.c for some hints on how this can be used.
62 */
63
64/* BIO_DEBUG implies BIO_PAIR_DEBUG */
65#ifdef BIO_DEBUG
66# ifndef BIO_PAIR_DEBUG
67#  define BIO_PAIR_DEBUG
68# endif
69#endif
70
71/* disable assert() unless BIO_PAIR_DEBUG has been defined */
72#ifndef BIO_PAIR_DEBUG
73# ifndef NDEBUG
74#  define NDEBUG
75# endif
76#endif
77
78#include <assert.h>
79#include <limits.h>
80#include <stdlib.h>
81#include <string.h>
82
83#include <openssl/bio.h>
84#include <openssl/err.h>
85#include <openssl/crypto.h>
86
87#include "e_os.h"
88
89/* VxWorks defines SSIZE_MAX with an empty value causing compile errors */
90#if defined(OPENSSL_SYS_VXWORKS)
91# undef SSIZE_MAX
92#endif
93#ifndef SSIZE_MAX
94# define SSIZE_MAX INT_MAX
95#endif
96
97static int bio_new(BIO *bio);
98static int bio_free(BIO *bio);
99static int bio_read(BIO *bio, char *buf, int size);
100static int bio_write(BIO *bio, const char *buf, int num);
101static long bio_ctrl(BIO *bio, int cmd, long num, void *ptr);
102static int bio_puts(BIO *bio, const char *str);
103
104static int bio_make_pair(BIO *bio1, BIO *bio2);
105static void bio_destroy_pair(BIO *bio);
106
107static BIO_METHOD methods_biop = {
108    BIO_TYPE_BIO,
109    "BIO pair",
110    bio_write,
111    bio_read,
112    bio_puts,
113    NULL /* no bio_gets */ ,
114    bio_ctrl,
115    bio_new,
116    bio_free,
117    NULL                        /* no bio_callback_ctrl */
118};
119
120BIO_METHOD *BIO_s_bio(void)
121{
122    return &methods_biop;
123}
124
125struct bio_bio_st {
126    BIO *peer;                  /* NULL if buf == NULL. If peer != NULL, then
127                                 * peer->ptr is also a bio_bio_st, and its
128                                 * "peer" member points back to us. peer !=
129                                 * NULL iff init != 0 in the BIO. */
130    /* This is for what we write (i.e. reading uses peer's struct): */
131    int closed;                 /* valid iff peer != NULL */
132    size_t len;                 /* valid iff buf != NULL; 0 if peer == NULL */
133    size_t offset;              /* valid iff buf != NULL; 0 if len == 0 */
134    size_t size;
135    char *buf;                  /* "size" elements (if != NULL) */
136    size_t request;             /* valid iff peer != NULL; 0 if len != 0,
137                                 * otherwise set by peer to number of bytes
138                                 * it (unsuccessfully) tried to read, never
139                                 * more than buffer space (size-len)
140                                 * warrants. */
141};
142
143static int bio_new(BIO *bio)
144{
145    struct bio_bio_st *b;
146
147    b = OPENSSL_malloc(sizeof(*b));
148    if (b == NULL)
149        return 0;
150
151    b->peer = NULL;
152    b->closed = 0;
153    b->len = 0;
154    b->offset = 0;
155    /* enough for one TLS record (just a default) */
156    b->size = 17 * 1024;
157    b->buf = NULL;
158    b->request = 0;
159
160    bio->ptr = b;
161    return 1;
162}
163
164static int bio_free(BIO *bio)
165{
166    struct bio_bio_st *b;
167
168    if (bio == NULL)
169        return 0;
170    b = bio->ptr;
171
172    assert(b != NULL);
173
174    if (b->peer)
175        bio_destroy_pair(bio);
176
177    if (b->buf != NULL) {
178        OPENSSL_free(b->buf);
179    }
180
181    OPENSSL_free(b);
182
183    return 1;
184}
185
186static int bio_read(BIO *bio, char *buf, int size_)
187{
188    size_t size = size_;
189    size_t rest;
190    struct bio_bio_st *b, *peer_b;
191
192    BIO_clear_retry_flags(bio);
193
194    if (!bio->init)
195        return 0;
196
197    b = bio->ptr;
198    assert(b != NULL);
199    assert(b->peer != NULL);
200    peer_b = b->peer->ptr;
201    assert(peer_b != NULL);
202    assert(peer_b->buf != NULL);
203
204    peer_b->request = 0;        /* will be set in "retry_read" situation */
205
206    if (buf == NULL || size == 0)
207        return 0;
208
209    if (peer_b->len == 0) {
210        if (peer_b->closed)
211            return 0;           /* writer has closed, and no data is left */
212        else {
213            BIO_set_retry_read(bio); /* buffer is empty */
214            if (size <= peer_b->size)
215                peer_b->request = size;
216            else
217                /*
218                 * don't ask for more than the peer can deliver in one write
219                 */
220                peer_b->request = peer_b->size;
221            return -1;
222        }
223    }
224
225    /* we can read */
226    if (peer_b->len < size)
227        size = peer_b->len;
228
229    /* now read "size" bytes */
230
231    rest = size;
232
233    assert(rest > 0);
234    do {                        /* one or two iterations */
235        size_t chunk;
236
237        assert(rest <= peer_b->len);
238        if (peer_b->offset + rest <= peer_b->size)
239            chunk = rest;
240        else
241            /* wrap around ring buffer */
242            chunk = peer_b->size - peer_b->offset;
243        assert(peer_b->offset + chunk <= peer_b->size);
244
245        memcpy(buf, peer_b->buf + peer_b->offset, chunk);
246
247        peer_b->len -= chunk;
248        if (peer_b->len) {
249            peer_b->offset += chunk;
250            assert(peer_b->offset <= peer_b->size);
251            if (peer_b->offset == peer_b->size)
252                peer_b->offset = 0;
253            buf += chunk;
254        } else {
255            /* buffer now empty, no need to advance "buf" */
256            assert(chunk == rest);
257            peer_b->offset = 0;
258        }
259        rest -= chunk;
260    }
261    while (rest);
262
263    return size;
264}
265
266/*-
267 * non-copying interface: provide pointer to available data in buffer
268 *    bio_nread0:  return number of available bytes
269 *    bio_nread:   also advance index
270 * (example usage:  bio_nread0(), read from buffer, bio_nread()
271 *  or just         bio_nread(), read from buffer)
272 */
273/*
274 * WARNING: The non-copying interface is largely untested as of yet and may
275 * contain bugs.
276 */
277static ossl_ssize_t bio_nread0(BIO *bio, char **buf)
278{
279    struct bio_bio_st *b, *peer_b;
280    ossl_ssize_t num;
281
282    BIO_clear_retry_flags(bio);
283
284    if (!bio->init)
285        return 0;
286
287    b = bio->ptr;
288    assert(b != NULL);
289    assert(b->peer != NULL);
290    peer_b = b->peer->ptr;
291    assert(peer_b != NULL);
292    assert(peer_b->buf != NULL);
293
294    peer_b->request = 0;
295
296    if (peer_b->len == 0) {
297        char dummy;
298
299        /* avoid code duplication -- nothing available for reading */
300        return bio_read(bio, &dummy, 1); /* returns 0 or -1 */
301    }
302
303    num = peer_b->len;
304    if (peer_b->size < peer_b->offset + num)
305        /* no ring buffer wrap-around for non-copying interface */
306        num = peer_b->size - peer_b->offset;
307    assert(num > 0);
308
309    if (buf != NULL)
310        *buf = peer_b->buf + peer_b->offset;
311    return num;
312}
313
314static ossl_ssize_t bio_nread(BIO *bio, char **buf, size_t num_)
315{
316    struct bio_bio_st *b, *peer_b;
317    ossl_ssize_t num, available;
318
319    if (num_ > SSIZE_MAX)
320        num = SSIZE_MAX;
321    else
322        num = (ossl_ssize_t) num_;
323
324    available = bio_nread0(bio, buf);
325    if (num > available)
326        num = available;
327    if (num <= 0)
328        return num;
329
330    b = bio->ptr;
331    peer_b = b->peer->ptr;
332
333    peer_b->len -= num;
334    if (peer_b->len) {
335        peer_b->offset += num;
336        assert(peer_b->offset <= peer_b->size);
337        if (peer_b->offset == peer_b->size)
338            peer_b->offset = 0;
339    } else
340        peer_b->offset = 0;
341
342    return num;
343}
344
345static int bio_write(BIO *bio, const char *buf, int num_)
346{
347    size_t num = num_;
348    size_t rest;
349    struct bio_bio_st *b;
350
351    BIO_clear_retry_flags(bio);
352
353    if (!bio->init || buf == NULL || num == 0)
354        return 0;
355
356    b = bio->ptr;
357    assert(b != NULL);
358    assert(b->peer != NULL);
359    assert(b->buf != NULL);
360
361    b->request = 0;
362    if (b->closed) {
363        /* we already closed */
364        BIOerr(BIO_F_BIO_WRITE, BIO_R_BROKEN_PIPE);
365        return -1;
366    }
367
368    assert(b->len <= b->size);
369
370    if (b->len == b->size) {
371        BIO_set_retry_write(bio); /* buffer is full */
372        return -1;
373    }
374
375    /* we can write */
376    if (num > b->size - b->len)
377        num = b->size - b->len;
378
379    /* now write "num" bytes */
380
381    rest = num;
382
383    assert(rest > 0);
384    do {                        /* one or two iterations */
385        size_t write_offset;
386        size_t chunk;
387
388        assert(b->len + rest <= b->size);
389
390        write_offset = b->offset + b->len;
391        if (write_offset >= b->size)
392            write_offset -= b->size;
393        /* b->buf[write_offset] is the first byte we can write to. */
394
395        if (write_offset + rest <= b->size)
396            chunk = rest;
397        else
398            /* wrap around ring buffer */
399            chunk = b->size - write_offset;
400
401        memcpy(b->buf + write_offset, buf, chunk);
402
403        b->len += chunk;
404
405        assert(b->len <= b->size);
406
407        rest -= chunk;
408        buf += chunk;
409    }
410    while (rest);
411
412    return num;
413}
414
415/*-
416 * non-copying interface: provide pointer to region to write to
417 *   bio_nwrite0:  check how much space is available
418 *   bio_nwrite:   also increase length
419 * (example usage:  bio_nwrite0(), write to buffer, bio_nwrite()
420 *  or just         bio_nwrite(), write to buffer)
421 */
422static ossl_ssize_t bio_nwrite0(BIO *bio, char **buf)
423{
424    struct bio_bio_st *b;
425    size_t num;
426    size_t write_offset;
427
428    BIO_clear_retry_flags(bio);
429
430    if (!bio->init)
431        return 0;
432
433    b = bio->ptr;
434    assert(b != NULL);
435    assert(b->peer != NULL);
436    assert(b->buf != NULL);
437
438    b->request = 0;
439    if (b->closed) {
440        BIOerr(BIO_F_BIO_NWRITE0, BIO_R_BROKEN_PIPE);
441        return -1;
442    }
443
444    assert(b->len <= b->size);
445
446    if (b->len == b->size) {
447        BIO_set_retry_write(bio);
448        return -1;
449    }
450
451    num = b->size - b->len;
452    write_offset = b->offset + b->len;
453    if (write_offset >= b->size)
454        write_offset -= b->size;
455    if (write_offset + num > b->size)
456        /*
457         * no ring buffer wrap-around for non-copying interface (to fulfil
458         * the promise by BIO_ctrl_get_write_guarantee, BIO_nwrite may have
459         * to be called twice)
460         */
461        num = b->size - write_offset;
462
463    if (buf != NULL)
464        *buf = b->buf + write_offset;
465    assert(write_offset + num <= b->size);
466
467    return num;
468}
469
470static ossl_ssize_t bio_nwrite(BIO *bio, char **buf, size_t num_)
471{
472    struct bio_bio_st *b;
473    ossl_ssize_t num, space;
474
475    if (num_ > SSIZE_MAX)
476        num = SSIZE_MAX;
477    else
478        num = (ossl_ssize_t) num_;
479
480    space = bio_nwrite0(bio, buf);
481    if (num > space)
482        num = space;
483    if (num <= 0)
484        return num;
485    b = bio->ptr;
486    assert(b != NULL);
487    b->len += num;
488    assert(b->len <= b->size);
489
490    return num;
491}
492
493static long bio_ctrl(BIO *bio, int cmd, long num, void *ptr)
494{
495    long ret;
496    struct bio_bio_st *b = bio->ptr;
497
498    assert(b != NULL);
499
500    switch (cmd) {
501        /* specific CTRL codes */
502
503    case BIO_C_SET_WRITE_BUF_SIZE:
504        if (b->peer) {
505            BIOerr(BIO_F_BIO_CTRL, BIO_R_IN_USE);
506            ret = 0;
507        } else if (num == 0) {
508            BIOerr(BIO_F_BIO_CTRL, BIO_R_INVALID_ARGUMENT);
509            ret = 0;
510        } else {
511            size_t new_size = num;
512
513            if (b->size != new_size) {
514                if (b->buf) {
515                    OPENSSL_free(b->buf);
516                    b->buf = NULL;
517                }
518                b->size = new_size;
519            }
520            ret = 1;
521        }
522        break;
523
524    case BIO_C_GET_WRITE_BUF_SIZE:
525        ret = (long)b->size;
526        break;
527
528    case BIO_C_MAKE_BIO_PAIR:
529        {
530            BIO *other_bio = ptr;
531
532            if (bio_make_pair(bio, other_bio))
533                ret = 1;
534            else
535                ret = 0;
536        }
537        break;
538
539    case BIO_C_DESTROY_BIO_PAIR:
540        /*
541         * Affects both BIOs in the pair -- call just once! Or let
542         * BIO_free(bio1); BIO_free(bio2); do the job.
543         */
544        bio_destroy_pair(bio);
545        ret = 1;
546        break;
547
548    case BIO_C_GET_WRITE_GUARANTEE:
549        /*
550         * How many bytes can the caller feed to the next write without
551         * having to keep any?
552         */
553        if (b->peer == NULL || b->closed)
554            ret = 0;
555        else
556            ret = (long)b->size - b->len;
557        break;
558
559    case BIO_C_GET_READ_REQUEST:
560        /*
561         * If the peer unsuccessfully tried to read, how many bytes were
562         * requested? (As with BIO_CTRL_PENDING, that number can usually be
563         * treated as boolean.)
564         */
565        ret = (long)b->request;
566        break;
567
568    case BIO_C_RESET_READ_REQUEST:
569        /*
570         * Reset request.  (Can be useful after read attempts at the other
571         * side that are meant to be non-blocking, e.g. when probing SSL_read
572         * to see if any data is available.)
573         */
574        b->request = 0;
575        ret = 1;
576        break;
577
578    case BIO_C_SHUTDOWN_WR:
579        /* similar to shutdown(..., SHUT_WR) */
580        b->closed = 1;
581        ret = 1;
582        break;
583
584    case BIO_C_NREAD0:
585        /* prepare for non-copying read */
586        ret = (long)bio_nread0(bio, ptr);
587        break;
588
589    case BIO_C_NREAD:
590        /* non-copying read */
591        ret = (long)bio_nread(bio, ptr, (size_t)num);
592        break;
593
594    case BIO_C_NWRITE0:
595        /* prepare for non-copying write */
596        ret = (long)bio_nwrite0(bio, ptr);
597        break;
598
599    case BIO_C_NWRITE:
600        /* non-copying write */
601        ret = (long)bio_nwrite(bio, ptr, (size_t)num);
602        break;
603
604        /* standard CTRL codes follow */
605
606    case BIO_CTRL_RESET:
607        if (b->buf != NULL) {
608            b->len = 0;
609            b->offset = 0;
610        }
611        ret = 0;
612        break;
613
614    case BIO_CTRL_GET_CLOSE:
615        ret = bio->shutdown;
616        break;
617
618    case BIO_CTRL_SET_CLOSE:
619        bio->shutdown = (int)num;
620        ret = 1;
621        break;
622
623    case BIO_CTRL_PENDING:
624        if (b->peer != NULL) {
625            struct bio_bio_st *peer_b = b->peer->ptr;
626
627            ret = (long)peer_b->len;
628        } else
629            ret = 0;
630        break;
631
632    case BIO_CTRL_WPENDING:
633        if (b->buf != NULL)
634            ret = (long)b->len;
635        else
636            ret = 0;
637        break;
638
639    case BIO_CTRL_DUP:
640        /* See BIO_dup_chain for circumstances we have to expect. */
641        {
642            BIO *other_bio = ptr;
643            struct bio_bio_st *other_b;
644
645            assert(other_bio != NULL);
646            other_b = other_bio->ptr;
647            assert(other_b != NULL);
648
649            assert(other_b->buf == NULL); /* other_bio is always fresh */
650
651            other_b->size = b->size;
652        }
653
654        ret = 1;
655        break;
656
657    case BIO_CTRL_FLUSH:
658        ret = 1;
659        break;
660
661    case BIO_CTRL_EOF:
662        if (b->peer != NULL) {
663            struct bio_bio_st *peer_b = b->peer->ptr;
664
665            if (peer_b->len == 0 && peer_b->closed)
666                ret = 1;
667            else
668                ret = 0;
669        } else {
670            ret = 1;
671        }
672        break;
673
674    default:
675        ret = 0;
676    }
677    return ret;
678}
679
680static int bio_puts(BIO *bio, const char *str)
681{
682    return bio_write(bio, str, strlen(str));
683}
684
685static int bio_make_pair(BIO *bio1, BIO *bio2)
686{
687    struct bio_bio_st *b1, *b2;
688
689    assert(bio1 != NULL);
690    assert(bio2 != NULL);
691
692    b1 = bio1->ptr;
693    b2 = bio2->ptr;
694
695    if (b1->peer != NULL || b2->peer != NULL) {
696        BIOerr(BIO_F_BIO_MAKE_PAIR, BIO_R_IN_USE);
697        return 0;
698    }
699
700    if (b1->buf == NULL) {
701        b1->buf = OPENSSL_malloc(b1->size);
702        if (b1->buf == NULL) {
703            BIOerr(BIO_F_BIO_MAKE_PAIR, ERR_R_MALLOC_FAILURE);
704            return 0;
705        }
706        b1->len = 0;
707        b1->offset = 0;
708    }
709
710    if (b2->buf == NULL) {
711        b2->buf = OPENSSL_malloc(b2->size);
712        if (b2->buf == NULL) {
713            BIOerr(BIO_F_BIO_MAKE_PAIR, ERR_R_MALLOC_FAILURE);
714            return 0;
715        }
716        b2->len = 0;
717        b2->offset = 0;
718    }
719
720    b1->peer = bio2;
721    b1->closed = 0;
722    b1->request = 0;
723    b2->peer = bio1;
724    b2->closed = 0;
725    b2->request = 0;
726
727    bio1->init = 1;
728    bio2->init = 1;
729
730    return 1;
731}
732
733static void bio_destroy_pair(BIO *bio)
734{
735    struct bio_bio_st *b = bio->ptr;
736
737    if (b != NULL) {
738        BIO *peer_bio = b->peer;
739
740        if (peer_bio != NULL) {
741            struct bio_bio_st *peer_b = peer_bio->ptr;
742
743            assert(peer_b != NULL);
744            assert(peer_b->peer == bio);
745
746            peer_b->peer = NULL;
747            peer_bio->init = 0;
748            assert(peer_b->buf != NULL);
749            peer_b->len = 0;
750            peer_b->offset = 0;
751
752            b->peer = NULL;
753            bio->init = 0;
754            assert(b->buf != NULL);
755            b->len = 0;
756            b->offset = 0;
757        }
758    }
759}
760
761/* Exported convenience functions */
762int BIO_new_bio_pair(BIO **bio1_p, size_t writebuf1,
763                     BIO **bio2_p, size_t writebuf2)
764{
765    BIO *bio1 = NULL, *bio2 = NULL;
766    long r;
767    int ret = 0;
768
769    bio1 = BIO_new(BIO_s_bio());
770    if (bio1 == NULL)
771        goto err;
772    bio2 = BIO_new(BIO_s_bio());
773    if (bio2 == NULL)
774        goto err;
775
776    if (writebuf1) {
777        r = BIO_set_write_buf_size(bio1, writebuf1);
778        if (!r)
779            goto err;
780    }
781    if (writebuf2) {
782        r = BIO_set_write_buf_size(bio2, writebuf2);
783        if (!r)
784            goto err;
785    }
786
787    r = BIO_make_bio_pair(bio1, bio2);
788    if (!r)
789        goto err;
790    ret = 1;
791
792 err:
793    if (ret == 0) {
794        if (bio1) {
795            BIO_free(bio1);
796            bio1 = NULL;
797        }
798        if (bio2) {
799            BIO_free(bio2);
800            bio2 = NULL;
801        }
802    }
803
804    *bio1_p = bio1;
805    *bio2_p = bio2;
806    return ret;
807}
808
809size_t BIO_ctrl_get_write_guarantee(BIO *bio)
810{
811    return BIO_ctrl(bio, BIO_C_GET_WRITE_GUARANTEE, 0, NULL);
812}
813
814size_t BIO_ctrl_get_read_request(BIO *bio)
815{
816    return BIO_ctrl(bio, BIO_C_GET_READ_REQUEST, 0, NULL);
817}
818
819int BIO_ctrl_reset_read_request(BIO *bio)
820{
821    return (BIO_ctrl(bio, BIO_C_RESET_READ_REQUEST, 0, NULL) != 0);
822}
823
824/*
825 * BIO_nread0/nread/nwrite0/nwrite are available only for BIO pairs for now
826 * (conceivably some other BIOs could allow non-copying reads and writes
827 * too.)
828 */
829int BIO_nread0(BIO *bio, char **buf)
830{
831    long ret;
832
833    if (!bio->init) {
834        BIOerr(BIO_F_BIO_NREAD0, BIO_R_UNINITIALIZED);
835        return -2;
836    }
837
838    ret = BIO_ctrl(bio, BIO_C_NREAD0, 0, buf);
839    if (ret > INT_MAX)
840        return INT_MAX;
841    else
842        return (int)ret;
843}
844
845int BIO_nread(BIO *bio, char **buf, int num)
846{
847    int ret;
848
849    if (!bio->init) {
850        BIOerr(BIO_F_BIO_NREAD, BIO_R_UNINITIALIZED);
851        return -2;
852    }
853
854    ret = (int)BIO_ctrl(bio, BIO_C_NREAD, num, buf);
855    if (ret > 0)
856        bio->num_read += ret;
857    return ret;
858}
859
860int BIO_nwrite0(BIO *bio, char **buf)
861{
862    long ret;
863
864    if (!bio->init) {
865        BIOerr(BIO_F_BIO_NWRITE0, BIO_R_UNINITIALIZED);
866        return -2;
867    }
868
869    ret = BIO_ctrl(bio, BIO_C_NWRITE0, 0, buf);
870    if (ret > INT_MAX)
871        return INT_MAX;
872    else
873        return (int)ret;
874}
875
876int BIO_nwrite(BIO *bio, char **buf, int num)
877{
878    int ret;
879
880    if (!bio->init) {
881        BIOerr(BIO_F_BIO_NWRITE, BIO_R_UNINITIALIZED);
882        return -2;
883    }
884
885    ret = BIO_ctrl(bio, BIO_C_NWRITE, num, buf);
886    if (ret > 0)
887        bio->num_write += ret;
888    return ret;
889}
890