ssl/libcrypto/src/crypto/bio/bss_bio.c
changeset 31 ce057bb09d0b
parent 0 e4d67989cc36
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/ssl/libcrypto/src/crypto/bio/bss_bio.c	Fri Jun 04 16:20:51 2010 +0100
@@ -0,0 +1,950 @@
+/* crypto/bio/bss_bio.c  -*- Mode: C; c-file-style: "eay" -*- */
+/* ====================================================================
+ * Copyright (c) 1998-2003 The OpenSSL Project.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer. 
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *
+ * 3. All advertising materials mentioning features or use of this
+ *    software must display the following acknowledgment:
+ *    "This product includes software developed by the OpenSSL Project
+ *    for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
+ *
+ * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
+ *    endorse or promote products derived from this software without
+ *    prior written permission. For written permission, please contact
+ *    openssl-core@openssl.org.
+ *
+ * 5. Products derived from this software may not be called "OpenSSL"
+ *    nor may "OpenSSL" appear in their names without prior written
+ *    permission of the OpenSSL Project.
+ *
+ * 6. Redistributions of any form whatsoever must retain the following
+ *    acknowledgment:
+ *    "This product includes software developed by the OpenSSL Project
+ *    for use in the OpenSSL Toolkit (http://www.openssl.org/)"
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
+ * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
+ * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ * ====================================================================
+ *
+ * This product includes cryptographic software written by Eric Young
+ * (eay@cryptsoft.com).  This product includes software written by Tim
+ * Hudson (tjh@cryptsoft.com).
+ *
+ */
+/*
+ © Portions copyright (c) 2006 Nokia Corporation.  All rights reserved.
+ */
+
+/* Special method for a BIO where the other endpoint is also a BIO
+ * of this kind, handled by the same thread (i.e. the "peer" is actually
+ * ourselves, wearing a different hat).
+ * Such "BIO pairs" are mainly for using the SSL library with I/O interfaces
+ * for which no specific BIO method is available.
+ * See ssl/ssltest.c for some hints on how this can be used. */
+
+/* BIO_DEBUG implies BIO_PAIR_DEBUG */
+#ifdef BIO_DEBUG
+# ifndef BIO_PAIR_DEBUG
+#  define BIO_PAIR_DEBUG
+# endif
+#endif
+
+/* disable assert() unless BIO_PAIR_DEBUG has been defined */
+#ifndef BIO_PAIR_DEBUG
+# ifndef NDEBUG
+#  define NDEBUG
+# endif
+#endif
+
+#include <assert.h>
+#include <limits.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <openssl/bio.h>
+#include <openssl/err.h>
+#include <openssl/crypto.h>
+
+#include "e_os.h"
+#if (defined(SYMBIAN) && (defined(__WINSCW__) || defined(__WINS__)))
+#include "libcrypto_wsd_macros.h"
+#include "libcrypto_wsd.h"
+#endif
+
+/* VxWorks defines SSIZE_MAX with an empty value causing compile errors */
+#if defined(OPENSSL_SYS_VXWORKS)
+# undef SSIZE_MAX
+#endif
+#ifndef SSIZE_MAX
+# define SSIZE_MAX INT_MAX
+#endif
+
+static int bio_new(BIO *bio);
+static int bio_free(BIO *bio);
+static int bio_read(BIO *bio, char *buf, int size);
+static int bio_write(BIO *bio, const char *buf, int num);
+static long bio_ctrl(BIO *bio, int cmd, long num, void *ptr);
+static int bio_puts(BIO *bio, const char *str);
+
+static int bio_make_pair(BIO *bio1, BIO *bio2);
+static void bio_destroy_pair(BIO *bio);
+
+#ifndef EMULATOR
+static BIO_METHOD methods_biop =
+{
+	BIO_TYPE_BIO,
+	"BIO pair",
+	bio_write,
+	bio_read,
+	bio_puts,
+	NULL /* no bio_gets */,
+	bio_ctrl,
+	bio_new,
+	bio_free,
+	NULL /* no bio_callback_ctrl */
+};
+#else
+
+GET_STATIC_VAR_FROM_TLS(methods_biop,bss_bio,BIO_METHOD)
+#define methods_biop (*GET_WSD_VAR_NAME(methods_biop,bss_bio,s)())
+const BIO_METHOD temp_s_methods_biop =
+{
+	BIO_TYPE_BIO,
+	"BIO pair",
+	bio_write,
+	bio_read,
+	bio_puts,
+	NULL /* no bio_gets */,
+	bio_ctrl,
+	bio_new,
+	bio_free,
+	NULL /* no bio_callback_ctrl */
+};
+#endif	
+
+EXPORT_C BIO_METHOD *BIO_s_bio(void)
+	{
+	return &methods_biop;
+	}
+
+struct bio_bio_st
+{
+	BIO *peer;     /* NULL if buf == NULL.
+	                * If peer != NULL, then peer->ptr is also a bio_bio_st,
+	                * and its "peer" member points back to us.
+	                * peer != NULL iff init != 0 in the BIO. */
+	
+	/* This is for what we write (i.e. reading uses peer's struct): */
+	int closed;     /* valid iff peer != NULL */
+	size_t len;     /* valid iff buf != NULL; 0 if peer == NULL */
+	size_t offset;  /* valid iff buf != NULL; 0 if len == 0 */
+	size_t size;
+	char *buf;      /* "size" elements (if != NULL) */
+
+	size_t request; /* valid iff peer != NULL; 0 if len != 0,
+	                 * otherwise set by peer to number of bytes
+	                 * it (unsuccessfully) tried to read,
+	                 * never more than buffer space (size-len) warrants. */
+};
+
+static int bio_new(BIO *bio)
+	{
+	struct bio_bio_st *b;
+	
+	b = OPENSSL_malloc(sizeof *b);
+	if (b == NULL)
+		return 0;
+
+	b->peer = NULL;
+	b->size = 17*1024; /* enough for one TLS record (just a default) */
+	b->buf = NULL;
+
+	bio->ptr = b;
+	return 1;
+	}
+
+
+static int bio_free(BIO *bio)
+	{
+	struct bio_bio_st *b;
+
+	if (bio == NULL)
+		return 0;
+	b = bio->ptr;
+
+	assert(b != NULL);
+
+	if (b->peer)
+		bio_destroy_pair(bio);
+	
+	if (b->buf != NULL)
+		{
+		OPENSSL_free(b->buf);
+		}
+
+	OPENSSL_free(b);
+
+	return 1;
+	}
+
+
+
+static int bio_read(BIO *bio, char *buf, int size_)
+	{
+	size_t size = size_;
+	size_t rest;
+	struct bio_bio_st *b, *peer_b;
+
+	BIO_clear_retry_flags(bio);
+
+	if (!bio->init)
+		return 0;
+
+	b = bio->ptr;
+	assert(b != NULL);
+	assert(b->peer != NULL);
+	peer_b = b->peer->ptr;
+	assert(peer_b != NULL);
+	assert(peer_b->buf != NULL);
+
+	peer_b->request = 0; /* will be set in "retry_read" situation */
+
+	if (buf == NULL || size == 0)
+		return 0;
+
+	if (peer_b->len == 0)
+		{
+		if (peer_b->closed)
+			return 0; /* writer has closed, and no data is left */
+		else
+			{
+			BIO_set_retry_read(bio); /* buffer is empty */
+			if (size <= peer_b->size)
+				peer_b->request = size;
+			else
+				/* don't ask for more than the peer can
+				 * deliver in one write */
+				peer_b->request = peer_b->size;
+			return -1;
+			}
+		}
+
+	/* we can read */
+	if (peer_b->len < size)
+		size = peer_b->len;
+
+	/* now read "size" bytes */
+	
+	rest = size;
+	
+	assert(rest > 0);
+	do /* one or two iterations */
+		{
+		size_t chunk;
+		
+		assert(rest <= peer_b->len);
+		if (peer_b->offset + rest <= peer_b->size)
+			chunk = rest;
+		else
+			/* wrap around ring buffer */
+			chunk = peer_b->size - peer_b->offset;
+		assert(peer_b->offset + chunk <= peer_b->size);
+		
+		memcpy(buf, peer_b->buf + peer_b->offset, chunk);
+		
+		peer_b->len -= chunk;
+		if (peer_b->len)
+			{
+			peer_b->offset += chunk;
+			assert(peer_b->offset <= peer_b->size);
+			if (peer_b->offset == peer_b->size)
+				peer_b->offset = 0;
+			buf += chunk;
+			}
+		else
+			{
+			/* buffer now empty, no need to advance "buf" */
+			assert(chunk == rest);
+			peer_b->offset = 0;
+			}
+		rest -= chunk;
+		}
+	while (rest);
+	
+	return size;
+	}
+
+/* non-copying interface: provide pointer to available data in buffer
+ *    bio_nread0:  return number of available bytes
+ *    bio_nread:   also advance index
+ * (example usage:  bio_nread0(), read from buffer, bio_nread()
+ *  or just         bio_nread(), read from buffer)
+ */
+/* WARNING: The non-copying interface is largely untested as of yet
+ * and may contain bugs. */
+static ssize_t bio_nread0(BIO *bio, char **buf)
+	{
+	struct bio_bio_st *b, *peer_b;
+	ssize_t num;
+	
+	BIO_clear_retry_flags(bio);
+
+	if (!bio->init)
+		return 0;
+	
+	b = bio->ptr;
+	assert(b != NULL);
+	assert(b->peer != NULL);
+	peer_b = b->peer->ptr;
+	assert(peer_b != NULL);
+	assert(peer_b->buf != NULL);
+	
+	peer_b->request = 0;
+	
+	if (peer_b->len == 0)
+		{
+		char dummy;
+		
+		/* avoid code duplication -- nothing available for reading */
+		return bio_read(bio, &dummy, 1); /* returns 0 or -1 */
+		}
+
+	num = peer_b->len;
+	if (peer_b->size < peer_b->offset + num)
+		/* no ring buffer wrap-around for non-copying interface */
+		num = peer_b->size - peer_b->offset;
+	assert(num > 0);
+
+	if (buf != NULL)
+		*buf = peer_b->buf + peer_b->offset;
+	return num;
+	}
+
+static ssize_t bio_nread(BIO *bio, char **buf, size_t num_)
+	{
+	struct bio_bio_st *b, *peer_b;
+	ssize_t num, available;
+
+	if (num_ > SSIZE_MAX)
+		num = SSIZE_MAX;
+	else
+		num = (ssize_t)num_;
+
+	available = bio_nread0(bio, buf);
+	if (num > available)
+		num = available;
+	if (num <= 0)
+		return num;
+
+	b = bio->ptr;
+	peer_b = b->peer->ptr;
+
+	peer_b->len -= num;
+	if (peer_b->len) 
+		{
+		peer_b->offset += num;
+		assert(peer_b->offset <= peer_b->size);
+		if (peer_b->offset == peer_b->size)
+			peer_b->offset = 0;
+		}
+	else
+		peer_b->offset = 0;
+
+	return num;
+	}
+
+
+static int bio_write(BIO *bio, const char *buf, int num_)
+	{
+	size_t num = num_;
+	size_t rest;
+	struct bio_bio_st *b;
+
+	BIO_clear_retry_flags(bio);
+
+	if (!bio->init || buf == NULL || num == 0)
+		return 0;
+
+	b = bio->ptr;		
+	assert(b != NULL);
+	assert(b->peer != NULL);
+	assert(b->buf != NULL);
+
+	b->request = 0;
+	if (b->closed)
+		{
+		/* we already closed */
+		BIOerr(BIO_F_BIO_WRITE, BIO_R_BROKEN_PIPE);
+		return -1;
+		}
+
+	assert(b->len <= b->size);
+
+	if (b->len == b->size)
+		{
+		BIO_set_retry_write(bio); /* buffer is full */
+		return -1;
+		}
+
+	/* we can write */
+	if (num > b->size - b->len)
+		num = b->size - b->len;
+	
+	/* now write "num" bytes */
+
+	rest = num;
+	
+	assert(rest > 0);
+	do /* one or two iterations */
+		{
+		size_t write_offset;
+		size_t chunk;
+
+		assert(b->len + rest <= b->size);
+
+		write_offset = b->offset + b->len;
+		if (write_offset >= b->size)
+			write_offset -= b->size;
+		/* b->buf[write_offset] is the first byte we can write to. */
+
+		if (write_offset + rest <= b->size)
+			chunk = rest;
+		else
+			/* wrap around ring buffer */
+			chunk = b->size - write_offset;
+		
+		memcpy(b->buf + write_offset, buf, chunk);
+		
+		b->len += chunk;
+
+		assert(b->len <= b->size);
+		
+		rest -= chunk;
+		buf += chunk;
+		}
+	while (rest);
+
+	return num;
+	}
+
+/* non-copying interface: provide pointer to region to write to
+ *   bio_nwrite0:  check how much space is available
+ *   bio_nwrite:   also increase length
+ * (example usage:  bio_nwrite0(), write to buffer, bio_nwrite()
+ *  or just         bio_nwrite(), write to buffer)
+ */
+static ssize_t bio_nwrite0(BIO *bio, char **buf)
+	{
+	struct bio_bio_st *b;
+	size_t num;
+	size_t write_offset;
+
+	BIO_clear_retry_flags(bio);
+
+	if (!bio->init)
+		return 0;
+
+	b = bio->ptr;		
+	assert(b != NULL);
+	assert(b->peer != NULL);
+	assert(b->buf != NULL);
+
+	b->request = 0;
+	if (b->closed)
+		{
+		BIOerr(BIO_F_BIO_NWRITE0, BIO_R_BROKEN_PIPE);
+		return -1;
+		}
+
+	assert(b->len <= b->size);
+
+	if (b->len == b->size)
+		{
+		BIO_set_retry_write(bio);
+		return -1;
+		}
+
+	num = b->size - b->len;
+	write_offset = b->offset + b->len;
+	if (write_offset >= b->size)
+		write_offset -= b->size;
+	if (write_offset + num > b->size)
+		/* no ring buffer wrap-around for non-copying interface
+		 * (to fulfil the promise by BIO_ctrl_get_write_guarantee,
+		 * BIO_nwrite may have to be called twice) */
+		num = b->size - write_offset;
+
+	if (buf != NULL)
+		*buf = b->buf + write_offset;
+	assert(write_offset + num <= b->size);
+
+	return num;
+	}
+
+static ssize_t bio_nwrite(BIO *bio, char **buf, size_t num_)
+	{
+	struct bio_bio_st *b;
+	ssize_t num, space;
+
+	if (num_ > SSIZE_MAX)
+		num = SSIZE_MAX;
+	else
+		num = (ssize_t)num_;
+
+	space = bio_nwrite0(bio, buf);
+	if (num > space)
+		num = space;
+	if (num <= 0)
+		return num;
+	b = bio->ptr;
+	assert(b != NULL);
+	b->len += num;
+	assert(b->len <= b->size);
+
+	return num;
+	}
+
+
+static long bio_ctrl(BIO *bio, int cmd, long num, void *ptr)
+	{
+	long ret;
+	struct bio_bio_st *b = bio->ptr;
+	
+	assert(b != NULL);
+
+	switch (cmd)
+		{
+	/* specific CTRL codes */
+
+	case BIO_C_SET_WRITE_BUF_SIZE:
+		if (b->peer)
+			{
+			BIOerr(BIO_F_BIO_CTRL, BIO_R_IN_USE);
+			ret = 0;
+			}
+		else if (num == 0)
+			{
+			BIOerr(BIO_F_BIO_CTRL, BIO_R_INVALID_ARGUMENT);
+			ret = 0;
+			}
+		else
+			{
+			size_t new_size = num;
+
+			if (b->size != new_size)
+				{
+				if (b->buf) 
+					{
+					OPENSSL_free(b->buf);
+					b->buf = NULL;
+					}
+				b->size = new_size;
+				}
+			ret = 1;
+			}
+		break;
+
+	case BIO_C_GET_WRITE_BUF_SIZE:
+		ret = (long) b->size;
+		break;
+
+	case BIO_C_MAKE_BIO_PAIR:
+		{
+		BIO *other_bio = ptr;
+		
+		if (bio_make_pair(bio, other_bio))
+			ret = 1;
+		else
+			ret = 0;
+		}
+		break;
+		
+	case BIO_C_DESTROY_BIO_PAIR:
+		/* Affects both BIOs in the pair -- call just once!
+		 * Or let BIO_free(bio1); BIO_free(bio2); do the job. */
+		bio_destroy_pair(bio);
+		ret = 1;
+		break;
+
+	case BIO_C_GET_WRITE_GUARANTEE:
+		/* How many bytes can the caller feed to the next write
+		 * without having to keep any? */
+		if (b->peer == NULL || b->closed)
+			ret = 0;
+		else
+			ret = (long) b->size - b->len;
+		break;
+
+	case BIO_C_GET_READ_REQUEST:
+		/* If the peer unsuccessfully tried to read, how many bytes
+		 * were requested?  (As with BIO_CTRL_PENDING, that number
+		 * can usually be treated as boolean.) */
+		ret = (long) b->request;
+		break;
+
+	case BIO_C_RESET_READ_REQUEST:
+		/* Reset request.  (Can be useful after read attempts
+		 * at the other side that are meant to be non-blocking,
+		 * e.g. when probing SSL_read to see if any data is
+		 * available.) */
+		b->request = 0;
+		ret = 1;
+		break;
+
+	case BIO_C_SHUTDOWN_WR:
+		/* similar to shutdown(..., SHUT_WR) */
+		b->closed = 1;
+		ret = 1;
+		break;
+
+	case BIO_C_NREAD0:
+		/* prepare for non-copying read */
+		ret = (long) bio_nread0(bio, ptr);
+		break;
+		
+	case BIO_C_NREAD:
+		/* non-copying read */
+		ret = (long) bio_nread(bio, ptr, (size_t) num);
+		break;
+		
+	case BIO_C_NWRITE0:
+		/* prepare for non-copying write */
+		ret = (long) bio_nwrite0(bio, ptr);
+		break;
+
+	case BIO_C_NWRITE:
+		/* non-copying write */
+		ret = (long) bio_nwrite(bio, ptr, (size_t) num);
+		break;
+		
+
+	/* standard CTRL codes follow */
+
+	case BIO_CTRL_RESET:
+		if (b->buf != NULL)
+			{
+			b->len = 0;
+			b->offset = 0;
+			}
+		ret = 0;
+		break;		
+
+	case BIO_CTRL_GET_CLOSE:
+		ret = bio->shutdown;
+		break;
+
+	case BIO_CTRL_SET_CLOSE:
+		bio->shutdown = (int) num;
+		ret = 1;
+		break;
+
+	case BIO_CTRL_PENDING:
+		if (b->peer != NULL)
+			{
+			struct bio_bio_st *peer_b = b->peer->ptr;
+			
+			ret = (long) peer_b->len;
+			}
+		else
+			ret = 0;
+		break;
+
+	case BIO_CTRL_WPENDING:
+		if (b->buf != NULL)
+			ret = (long) b->len;
+		else
+			ret = 0;
+		break;
+
+	case BIO_CTRL_DUP:
+		/* See BIO_dup_chain for circumstances we have to expect. */
+		{
+		BIO *other_bio = ptr;
+		struct bio_bio_st *other_b;
+		
+		assert(other_bio != NULL);
+		other_b = other_bio->ptr;
+		assert(other_b != NULL);
+		
+		assert(other_b->buf == NULL); /* other_bio is always fresh */
+
+		other_b->size = b->size;
+		}
+
+		ret = 1;
+		break;
+
+	case BIO_CTRL_FLUSH:
+		ret = 1;
+		break;
+
+	case BIO_CTRL_EOF:
+		{
+		BIO *other_bio = ptr;
+		
+		if (other_bio)
+			{
+			struct bio_bio_st *other_b = other_bio->ptr;
+			
+			assert(other_b != NULL);
+			ret = other_b->len == 0 && other_b->closed;
+			}
+		else
+			ret = 1;
+		}
+		break;
+
+	default:
+		ret = 0;
+		}
+	return ret;
+	}
+
+static int bio_puts(BIO *bio, const char *str)
+	{
+	return bio_write(bio, str, strlen(str));
+	}
+
+
+static int bio_make_pair(BIO *bio1, BIO *bio2)
+	{
+	struct bio_bio_st *b1, *b2;
+
+	assert(bio1 != NULL);
+	assert(bio2 != NULL);
+
+	b1 = bio1->ptr;
+	b2 = bio2->ptr;
+	
+	if (b1->peer != NULL || b2->peer != NULL)
+		{
+		BIOerr(BIO_F_BIO_MAKE_PAIR, BIO_R_IN_USE);
+		return 0;
+		}
+	
+	if (b1->buf == NULL)
+		{
+		b1->buf = OPENSSL_malloc(b1->size);
+		if (b1->buf == NULL)
+			{
+			BIOerr(BIO_F_BIO_MAKE_PAIR, ERR_R_MALLOC_FAILURE);
+			return 0;
+			}
+		b1->len = 0;
+		b1->offset = 0;
+		}
+	
+	if (b2->buf == NULL)
+		{
+		b2->buf = OPENSSL_malloc(b2->size);
+		if (b2->buf == NULL)
+			{
+			BIOerr(BIO_F_BIO_MAKE_PAIR, ERR_R_MALLOC_FAILURE);
+			return 0;
+			}
+		b2->len = 0;
+		b2->offset = 0;
+		}
+	
+	b1->peer = bio2;
+	b1->closed = 0;
+	b1->request = 0;
+	b2->peer = bio1;
+	b2->closed = 0;
+	b2->request = 0;
+
+	bio1->init = 1;
+	bio2->init = 1;
+
+	return 1;
+	}
+
+static void bio_destroy_pair(BIO *bio)
+	{
+	struct bio_bio_st *b = bio->ptr;
+
+	if (b != NULL)
+		{
+		BIO *peer_bio = b->peer;
+
+		if (peer_bio != NULL)
+			{
+			struct bio_bio_st *peer_b = peer_bio->ptr;
+
+			assert(peer_b != NULL);
+			assert(peer_b->peer == bio);
+
+			peer_b->peer = NULL;
+			peer_bio->init = 0;
+			assert(peer_b->buf != NULL);
+			peer_b->len = 0;
+			peer_b->offset = 0;
+			
+			b->peer = NULL;
+			bio->init = 0;
+			assert(b->buf != NULL);
+			b->len = 0;
+			b->offset = 0;
+			}
+		}
+	}
+ 
+
+/* Exported convenience functions */
+EXPORT_C int BIO_new_bio_pair(BIO **bio1_p, size_t writebuf1,
+	BIO **bio2_p, size_t writebuf2)
+	 {
+	 BIO *bio1 = NULL, *bio2 = NULL;
+	 long r;
+	 int ret = 0;
+
+	 bio1 = BIO_new(BIO_s_bio());
+	 if (bio1 == NULL)
+		 goto err;
+	 bio2 = BIO_new(BIO_s_bio());
+	 if (bio2 == NULL)
+		 goto err;
+
+	 if (writebuf1)
+		 {
+		 r = BIO_set_write_buf_size(bio1, writebuf1);
+		 if (!r)
+			 goto err;
+		 }
+	 if (writebuf2)
+		 {
+		 r = BIO_set_write_buf_size(bio2, writebuf2);
+		 if (!r)
+			 goto err;
+		 }
+
+	 r = BIO_make_bio_pair(bio1, bio2);
+	 if (!r)
+		 goto err;
+	 ret = 1;
+
+ err:
+	 if (ret == 0)
+		 {
+		 if (bio1)
+			 {
+			 BIO_free(bio1);
+			 bio1 = NULL;
+			 }
+		 if (bio2)
+			 {
+			 BIO_free(bio2);
+			 bio2 = NULL;
+			 }
+		 }
+
+	 *bio1_p = bio1;
+	 *bio2_p = bio2;
+	 return ret;
+	 }
+
+EXPORT_C size_t BIO_ctrl_get_write_guarantee(BIO *bio)
+	{
+	return BIO_ctrl(bio, BIO_C_GET_WRITE_GUARANTEE, 0, NULL);
+	}
+
+EXPORT_C size_t BIO_ctrl_get_read_request(BIO *bio)
+	{
+	return BIO_ctrl(bio, BIO_C_GET_READ_REQUEST, 0, NULL);
+	}
+
+EXPORT_C int BIO_ctrl_reset_read_request(BIO *bio)
+	{
+	return (BIO_ctrl(bio, BIO_C_RESET_READ_REQUEST, 0, NULL) != 0);
+	}
+
+
+/* BIO_nread0/nread/nwrite0/nwrite are available only for BIO pairs for now
+ * (conceivably some other BIOs could allow non-copying reads and writes too.)
+ */
+EXPORT_C int BIO_nread0(BIO *bio, char **buf)
+	{
+	long ret;
+
+	if (!bio->init)
+		{
+		BIOerr(BIO_F_BIO_NREAD0, BIO_R_UNINITIALIZED);
+		return -2;
+		}
+
+	ret = BIO_ctrl(bio, BIO_C_NREAD0, 0, buf);
+	if (ret > INT_MAX)
+		return INT_MAX;
+	else
+		return (int) ret;
+	}
+
+EXPORT_C int BIO_nread(BIO *bio, char **buf, int num)
+	{
+	int ret;
+
+	if (!bio->init)
+		{
+		BIOerr(BIO_F_BIO_NREAD, BIO_R_UNINITIALIZED);
+		return -2;
+		}
+
+	ret = (int) BIO_ctrl(bio, BIO_C_NREAD, num, buf);
+	if (ret > 0)
+		bio->num_read += ret;
+	return ret;
+	}
+
+EXPORT_C int BIO_nwrite0(BIO *bio, char **buf)
+	{
+	long ret;
+
+	if (!bio->init)
+		{
+		BIOerr(BIO_F_BIO_NWRITE0, BIO_R_UNINITIALIZED);
+		return -2;
+		}
+
+	ret = BIO_ctrl(bio, BIO_C_NWRITE0, 0, buf);
+	if (ret > INT_MAX)
+		return INT_MAX;
+	else
+		return (int) ret;
+	}
+
+EXPORT_C int BIO_nwrite(BIO *bio, char **buf, int num)
+	{
+	int ret;
+
+	if (!bio->init)
+		{
+		BIOerr(BIO_F_BIO_NWRITE, BIO_R_UNINITIALIZED);
+		return -2;
+		}
+
+	ret = BIO_ctrl(bio, BIO_C_NWRITE, num, buf);
+	if (ret > 0)
+		bio->num_read += ret;
+	return ret;
+	}