/* 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;

	}