/* $OpenBSD: bf_lbuf.c,v 1.14 2017/01/29 17:49:22 beck 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 <openssl/bio.h>
#include <openssl/evp.h>

static int linebuffer_write(BIO *h, const char *buf, int num);
static int linebuffer_read(BIO *h, char *buf, int size);
static int linebuffer_puts(BIO *h, const char *str);
static int linebuffer_gets(BIO *h, char *str, int size);
static long linebuffer_ctrl(BIO *h, int cmd, long arg1, void *arg2);
static int linebuffer_new(BIO *h);
static int linebuffer_free(BIO *data);
static long linebuffer_callback_ctrl(BIO *h, int cmd, bio_info_cb *fp);

/* A 10k maximum should be enough for most purposes */
#define DEFAULT_LINEBUFFER_SIZE	1024*10

/* #define DEBUG */

static BIO_METHOD methods_linebuffer = {
	.type = BIO_TYPE_LINEBUFFER,
	.name = "linebuffer",
	.bwrite = linebuffer_write,
	.bread = linebuffer_read,
	.bputs = linebuffer_puts,
	.bgets = linebuffer_gets,
	.ctrl = linebuffer_ctrl,
	.create = linebuffer_new,
	.destroy = linebuffer_free,
	.callback_ctrl = linebuffer_callback_ctrl
};

BIO_METHOD *
BIO_f_linebuffer(void)
{
	return (&methods_linebuffer);
}

typedef struct bio_linebuffer_ctx_struct {
	char *obuf;		/* the output char array */
	int obuf_size;		/* how big is the output buffer */
	int obuf_len;		/* how many bytes are in it */
} BIO_LINEBUFFER_CTX;

static int
linebuffer_new(BIO *bi)
{
	BIO_LINEBUFFER_CTX *ctx;

	ctx = malloc(sizeof(BIO_LINEBUFFER_CTX));
	if (ctx == NULL)
		return (0);
	ctx->obuf = malloc(DEFAULT_LINEBUFFER_SIZE);
	if (ctx->obuf == NULL) {
		free(ctx);
		return (0);
	}
	ctx->obuf_size = DEFAULT_LINEBUFFER_SIZE;
	ctx->obuf_len = 0;

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

static int
linebuffer_free(BIO *a)
{
	BIO_LINEBUFFER_CTX *b;

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

static int
linebuffer_read(BIO *b, char *out, int outl)
{
	int ret = 0;

	if (out == NULL)
		return (0);
	if (b->next_bio == NULL)
		return (0);
	ret = BIO_read(b->next_bio, out, outl);
	BIO_clear_retry_flags(b);
	BIO_copy_next_retry(b);
	return (ret);
}

static int
linebuffer_write(BIO *b, const char *in, int inl)
{
	int i, num = 0, foundnl;
	BIO_LINEBUFFER_CTX *ctx;

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

	BIO_clear_retry_flags(b);

	do {
		const char *p;

		for (p = in; p < in + inl && *p != '\n'; p++)
			;
		if (*p == '\n') {
			p++;
			foundnl = 1;
		} else
			foundnl = 0;

		/* If a NL was found and we already have text in the save
		   buffer, concatenate them and write */
		while ((foundnl || p - in > ctx->obuf_size - ctx->obuf_len) &&
		    ctx->obuf_len > 0) {
			int orig_olen = ctx->obuf_len;

			i = ctx->obuf_size - ctx->obuf_len;
			if (p - in > 0) {
				if (i >= p - in) {
					memcpy(&(ctx->obuf[ctx->obuf_len]),
					    in, p - in);
					ctx->obuf_len += p - in;
					inl -= p - in;
					num += p - in;
					in = p;
				} else {
					memcpy(&(ctx->obuf[ctx->obuf_len]),
					    in, i);
					ctx->obuf_len += i;
					inl -= i;
					in += i;
					num += i;
				}
			}

			i = BIO_write(b->next_bio, ctx->obuf, ctx->obuf_len);
			if (i <= 0) {
				ctx->obuf_len = orig_olen;
				BIO_copy_next_retry(b);
				if (i < 0)
					return ((num > 0) ? num : i);
				if (i == 0)
					return (num);
			}
			if (i < ctx->obuf_len)
				memmove(ctx->obuf, ctx->obuf + i,
				    ctx->obuf_len - i);
			ctx->obuf_len -= i;
		}

		/* Now that the save buffer is emptied, let's write the input
		   buffer if a NL was found and there is anything to write. */
		if ((foundnl || p - in > ctx->obuf_size) && p - in > 0) {
			i = BIO_write(b->next_bio, in, p - in);
			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;
		}
	} while (foundnl && inl > 0);
	/* We've written as much as we can.  The rest of the input buffer, if
	   any, is text that doesn't and with a NL and therefore needs to be
	   saved for the next trip. */
	if (inl > 0) {
		memcpy(&(ctx->obuf[ctx->obuf_len]), in, inl);
		ctx->obuf_len += inl;
		num += inl;
	}
	return num;
}

static long
linebuffer_ctrl(BIO *b, int cmd, long num, void *ptr)
{
	BIO *dbio;
	BIO_LINEBUFFER_CTX *ctx;
	long ret = 1;
	char *p;
	int r;
	int obs;

	ctx = (BIO_LINEBUFFER_CTX *)b->ptr;

	switch (cmd) {
	case BIO_CTRL_RESET:
		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_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_C_SET_BUFF_SIZE:
		obs = (int)num;
		p = ctx->obuf;
		if ((obs > DEFAULT_LINEBUFFER_SIZE) && (obs != ctx->obuf_size)) {
			p = malloc(num);
			if (p == NULL)
				goto malloc_error;
		}
		if (ctx->obuf != p) {
			if (ctx->obuf_len > obs) {
				ctx->obuf_len = obs;
			}
			memcpy(p, ctx->obuf, ctx->obuf_len);
			free(ctx->obuf);
			ctx->obuf = p;
			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_len);
				BIO_copy_next_retry(b);
				if (r <= 0)
					return ((long)r);
				if (r < ctx->obuf_len)
					memmove(ctx->obuf, ctx->obuf + r,
					    ctx->obuf_len - r);
				ctx->obuf_len -= r;
			} else {
				ctx->obuf_len = 0;
				ret = 1;
				break;
			}
		}
		ret = BIO_ctrl(b->next_bio, cmd, num, ptr);
		break;
	case BIO_CTRL_DUP:
		dbio = (BIO *)ptr;
		if (!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
linebuffer_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
linebuffer_gets(BIO *b, char *buf, int size)
{
	if (b->next_bio == NULL)
		return (0);
	return (BIO_gets(b->next_bio, buf, size));
}

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