/* $OpenBSD: bf_buff.c,v 1.25 2018/05/01 13:29:09 tb Exp $ */
/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
 * All rights reserved.
 *
 * This package is an SSL implementation written
 * by Eric Young (eay@cryptsoft.com).
 * The implementation was written so as to conform with Netscapes SSL.
 *
 * This library is free for commercial and non-commercial use as long as
 * the following conditions are aheared to.  The following conditions
 * apply to all code found in this distribution, be it the RC4, RSA,
 * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
 * included with this distribution is covered by the same copyright terms
 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
 *
 * Copyright remains Eric Young's, and as such any Copyright notices in
 * the code are not to be removed.
 * If this package is used in a product, Eric Young should be given attribution
 * as the author of the parts of the library used.
 * This can be in the form of a textual message at program startup or
 * in documentation (online or textual) provided with the package.
 *
 * 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 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 acknowledgement:
 *    "This product includes cryptographic software written by
 *     Eric Young (eay@cryptsoft.com)"
 *    The word 'cryptographic' can be left out if the rouines from the library
 *    being used are not cryptographic related :-).
 * 4. If you include any Windows specific code (or a derivative thereof) from
 *    the apps directory (application code) you must include an acknowledgement:
 *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
 *
 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
 * ANY EXPRESS 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 AUTHOR OR 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.
 *
 * The licence and distribution terms for any publically available version or
 * derivative of this code cannot be changed.  i.e. this code cannot simply be
 * copied and put under another distribution licence
 * [including the GNU Public Licence.]
 */

#include <errno.h>
#include <stdio.h>
#include <string.h>

#include <openssl/bio.h>
#include <openssl/err.h>

static int buffer_write(BIO *h, const char *buf, int num);
static int buffer_read(BIO *h, char *buf, int size);
static int buffer_puts(BIO *h, const char *str);
static int buffer_gets(BIO *h, char *str, int size);
static long buffer_ctrl(BIO *h, int cmd, long arg1, void *arg2);
static int buffer_new(BIO *h);
static int buffer_free(BIO *data);
static long buffer_callback_ctrl(BIO *h, int cmd, bio_info_cb *fp);
#define DEFAULT_BUFFER_SIZE	4096

static const BIO_METHOD methods_buffer = {
	.type = BIO_TYPE_BUFFER,
	.name = "buffer",
	.bwrite = buffer_write,
	.bread = buffer_read,
	.bputs = buffer_puts,
	.bgets = buffer_gets,
	.ctrl = buffer_ctrl,
	.create = buffer_new,
	.destroy = buffer_free,
	.callback_ctrl = buffer_callback_ctrl
};

const BIO_METHOD *
BIO_f_buffer(void)
{
	return (&methods_buffer);
}

static int
buffer_new(BIO *bi)
{
	BIO_F_BUFFER_CTX *ctx;

	ctx = malloc(sizeof(BIO_F_BUFFER_CTX));
	if (ctx == NULL)
		return (0);
	ctx->ibuf = malloc(DEFAULT_BUFFER_SIZE);
	if (ctx->ibuf == NULL) {
		free(ctx);
		return (0);
	}
	ctx->obuf = malloc(DEFAULT_BUFFER_SIZE);
	if (ctx->obuf == NULL) {
		free(ctx->ibuf);
		free(ctx);
		return (0);
	}
	ctx->ibuf_size = DEFAULT_BUFFER_SIZE;
	ctx->obuf_size = DEFAULT_BUFFER_SIZE;
	ctx->ibuf_len = 0;
	ctx->ibuf_off = 0;
	ctx->obuf_len = 0;
	ctx->obuf_off = 0;

	bi->init = 1;
	bi->ptr = (char *)ctx;
	bi->flags = 0;
	return (1);
}

static int
buffer_free(BIO *a)
{
	BIO_F_BUFFER_CTX *b;

	if (a == NULL)
		return (0);
	b = (BIO_F_BUFFER_CTX *)a->ptr;
	free(b->ibuf);
	free(b->obuf);
	free(a->ptr);
	a->ptr = NULL;
	a->init = 0;
	a->flags = 0;
	return (1);
}

static int
buffer_read(BIO *b, char *out, int outl)
{
	int i, num = 0;
	BIO_F_BUFFER_CTX *ctx;

	if (out == NULL)
		return (0);
	ctx = (BIO_F_BUFFER_CTX *)b->ptr;

	if ((ctx == NULL) || (b->next_bio == NULL))
		return (0);
	num = 0;
	BIO_clear_retry_flags(b);

start:
	i = ctx->ibuf_len;
	/* If there is stuff left over, grab it */
	if (i != 0) {
		if (i > outl)
			i = outl;
		memcpy(out, &(ctx->ibuf[ctx->ibuf_off]), i);
		ctx->ibuf_off += i;
		ctx->ibuf_len -= i;
		num += i;
		if (outl == i)
			return (num);
		outl -= i;
		out += i;
	}

	/* We may have done a partial read. try to do more.
	 * We have nothing in the buffer.
	 * If we get an error and have read some data, just return it
	 * and let them retry to get the error again.
	 * copy direct to parent address space */
	if (outl > ctx->ibuf_size) {
		for (;;) {
			i = BIO_read(b->next_bio, out, outl);
			if (i <= 0) {
				BIO_copy_next_retry(b);
				if (i < 0)
					return ((num > 0) ? num : i);
				if (i == 0)
					return (num);
			}
			num += i;
			if (outl == i)
				return (num);
			out += i;
			outl -= i;
		}
	}
	/* else */

	/* we are going to be doing some buffering */
	i = BIO_read(b->next_bio, ctx->ibuf, ctx->ibuf_size);
	if (i <= 0) {
		BIO_copy_next_retry(b);
		if (i < 0)
			return ((num > 0) ? num : i);
		if (i == 0)
			return (num);
	}
	ctx->ibuf_off = 0;
	ctx->ibuf_len = i;

	/* Lets re-read using ourselves :-) */
	goto start;
}

static int
buffer_write(BIO *b, const char *in, int inl)
{
	int i, num = 0;
	BIO_F_BUFFER_CTX *ctx;

	if ((in == NULL) || (inl <= 0))
		return (0);
	ctx = (BIO_F_BUFFER_CTX *)b->ptr;
	if ((ctx == NULL) || (b->next_bio == NULL))
		return (0);

	BIO_clear_retry_flags(b);
start:
	i = ctx->obuf_size - (ctx->obuf_len + ctx->obuf_off);
	/* add to buffer and return */
	if (i >= inl) {
		memcpy(&(ctx->obuf[ctx->obuf_off + ctx->obuf_len]), in, inl);
		ctx->obuf_len += inl;
		return (num + inl);
	}
	/* else */
	/* stuff already in buffer, so add to it first, then flush */
	if (ctx->obuf_len != 0) {
		if (i > 0) /* lets fill it up if we can */
		{
			memcpy(&(ctx->obuf[ctx->obuf_off + ctx->obuf_len]), in, i);
			in += i;
			inl -= i;
			num += i;
			ctx->obuf_len += i;
		}
		/* we now have a full buffer needing flushing */
		for (;;) {
			i = BIO_write(b->next_bio, &(ctx->obuf[ctx->obuf_off]),
			    ctx->obuf_len);
			if (i <= 0) {
				BIO_copy_next_retry(b);

				if (i < 0)
					return ((num > 0) ? num : i);
				if (i == 0)
					return (num);
			}
			ctx->obuf_off += i;
			ctx->obuf_len -= i;
			if (ctx->obuf_len == 0)
				break;
		}
	}
	/* we only get here if the buffer has been flushed and we
	 * still have stuff to write */
	ctx->obuf_off = 0;

	/* we now have inl bytes to write */
	while (inl >= ctx->obuf_size) {
		i = BIO_write(b->next_bio, in, inl);
		if (i <= 0) {
			BIO_copy_next_retry(b);
			if (i < 0)
				return ((num > 0) ? num : i);
			if (i == 0)
				return (num);
		}
		num += i;
		in += i;
		inl -= i;
		if (inl == 0)
			return (num);
	}

	/* copy the rest into the buffer since we have only a small
	 * amount left */
	goto start;
}

static long
buffer_ctrl(BIO *b, int cmd, long num, void *ptr)
{
	BIO *dbio;
	BIO_F_BUFFER_CTX *ctx;
	long ret = 1;
	char *p1, *p2;
	int r, i, *ip;
	int ibs, obs;

	ctx = (BIO_F_BUFFER_CTX *)b->ptr;

	switch (cmd) {
	case BIO_CTRL_RESET:
		ctx->ibuf_off = 0;
		ctx->ibuf_len = 0;
		ctx->obuf_off = 0;
		ctx->obuf_len = 0;
		if (b->next_bio == NULL)
			return (0);
		ret = BIO_ctrl(b->next_bio, cmd, num, ptr);
		break;
	case BIO_CTRL_INFO:
		ret = (long)ctx->obuf_len;
		break;
	case BIO_C_GET_BUFF_NUM_LINES:
		ret = 0;
		p1 = ctx->ibuf;
		for (i = 0; i < ctx->ibuf_len; i++) {
			if (p1[ctx->ibuf_off + i] == '\n')
				ret++;
		}
		break;
	case BIO_CTRL_WPENDING:
		ret = (long)ctx->obuf_len;
		if (ret == 0) {
			if (b->next_bio == NULL)
				return (0);
			ret = BIO_ctrl(b->next_bio, cmd, num, ptr);
		}
		break;
	case BIO_CTRL_PENDING:
		ret = (long)ctx->ibuf_len;
		if (ret == 0) {
			if (b->next_bio == NULL)
				return (0);
			ret = BIO_ctrl(b->next_bio, cmd, num, ptr);
		}
		break;
	case BIO_C_SET_BUFF_READ_DATA:
		if (num > ctx->ibuf_size) {
			p1 = malloc(num);
			if (p1 == NULL)
				goto malloc_error;
			free(ctx->ibuf);
			ctx->ibuf = p1;
		}
		ctx->ibuf_off = 0;
		ctx->ibuf_len = (int)num;
		memcpy(ctx->ibuf, ptr, num);
		ret = 1;
		break;
	case BIO_C_SET_BUFF_SIZE:
		if (ptr != NULL) {
			ip = (int *)ptr;
			if (*ip == 0) {
				ibs = (int)num;
				obs = ctx->obuf_size;
			}
			else /* if (*ip == 1) */
			{
				ibs = ctx->ibuf_size;
				obs = (int)num;
			}
		} else {
			ibs = (int)num;
			obs = (int)num;
		}
		p1 = ctx->ibuf;
		p2 = ctx->obuf;
		if ((ibs > DEFAULT_BUFFER_SIZE) && (ibs != ctx->ibuf_size)) {
			p1 = malloc(num);
			if (p1 == NULL)
				goto malloc_error;
		}
		if ((obs > DEFAULT_BUFFER_SIZE) && (obs != ctx->obuf_size)) {
			p2 = malloc(num);
			if (p2 == NULL) {
				if (p1 != ctx->ibuf)
					free(p1);
				goto malloc_error;
			}
		}
		if (ctx->ibuf != p1) {
			free(ctx->ibuf);
			ctx->ibuf = p1;
			ctx->ibuf_off = 0;
			ctx->ibuf_len = 0;
			ctx->ibuf_size = ibs;
		}
		if (ctx->obuf != p2) {
			free(ctx->obuf);
			ctx->obuf = p2;
			ctx->obuf_off = 0;
			ctx->obuf_len = 0;
			ctx->obuf_size = obs;
		}
		break;
	case BIO_C_DO_STATE_MACHINE:
		if (b->next_bio == NULL)
			return (0);
		BIO_clear_retry_flags(b);
		ret = BIO_ctrl(b->next_bio, cmd, num, ptr);
		BIO_copy_next_retry(b);
		break;

	case BIO_CTRL_FLUSH:
		if (b->next_bio == NULL)
			return (0);
		if (ctx->obuf_len <= 0) {
			ret = BIO_ctrl(b->next_bio, cmd, num, ptr);
			break;
		}

		for (;;) {
			BIO_clear_retry_flags(b);
			if (ctx->obuf_len > 0) {
				r = BIO_write(b->next_bio,
				    &(ctx->obuf[ctx->obuf_off]),
				    ctx->obuf_len);
				BIO_copy_next_retry(b);
				if (r <= 0)
					return ((long)r);
				ctx->obuf_off += r;
				ctx->obuf_len -= r;
			} else {
				ctx->obuf_len = 0;
				ctx->obuf_off = 0;
				break;
			}
		}
		ret = BIO_ctrl(b->next_bio, cmd, num, ptr);
		break;
	case BIO_CTRL_DUP:
		dbio = (BIO *)ptr;
		if (!BIO_set_read_buffer_size(dbio, ctx->ibuf_size) ||
		    !BIO_set_write_buffer_size(dbio, ctx->obuf_size))
			ret = 0;
		break;
	default:
		if (b->next_bio == NULL)
			return (0);
		ret = BIO_ctrl(b->next_bio, cmd, num, ptr);
		break;
	}
	return (ret);
malloc_error:
	BIOerror(ERR_R_MALLOC_FAILURE);
	return (0);
}

static long
buffer_callback_ctrl(BIO *b, int cmd, bio_info_cb *fp)
{
	long ret = 1;

	if (b->next_bio == NULL)
		return (0);
	switch (cmd) {
	default:
		ret = BIO_callback_ctrl(b->next_bio, cmd, fp);
		break;
	}
	return (ret);
}

static int
buffer_gets(BIO *b, char *buf, int size)
{
	BIO_F_BUFFER_CTX *ctx;
	int num = 0, i, flag;
	char *p;

	ctx = (BIO_F_BUFFER_CTX *)b->ptr;
	size--; /* reserve space for a '\0' */
	BIO_clear_retry_flags(b);

	for (;;) {
		if (ctx->ibuf_len > 0) {
			p = &(ctx->ibuf[ctx->ibuf_off]);
			flag = 0;
			for (i = 0; (i < ctx->ibuf_len) && (i < size); i++) {
				*(buf++) = p[i];
				if (p[i] == '\n') {
					flag = 1;
					i++;
					break;
				}
			}
			num += i;
			size -= i;
			ctx->ibuf_len -= i;
			ctx->ibuf_off += i;
			if (flag || size == 0) {
				*buf = '\0';
				return (num);
			}
		}
		else	/* read another chunk */
		{
			i = BIO_read(b->next_bio, ctx->ibuf, ctx->ibuf_size);
			if (i <= 0) {
				BIO_copy_next_retry(b);
				*buf = '\0';
				if (i < 0)
					return ((num > 0) ? num : i);
				if (i == 0)
					return (num);
			}
			ctx->ibuf_len = i;
			ctx->ibuf_off = 0;
		}
	}
}

static int
buffer_puts(BIO *b, const char *str)
{
	return (buffer_write(b, str, strlen(str)));
}
