/* $OpenBSD: bss_mem.c,v 1.15 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 <string.h>

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

static int mem_write(BIO *h, const char *buf, int num);
static int mem_read(BIO *h, char *buf, int size);
static int mem_puts(BIO *h, const char *str);
static int mem_gets(BIO *h, char *str, int size);
static long mem_ctrl(BIO *h, int cmd, long arg1, void *arg2);
static int mem_new(BIO *h);
static int mem_free(BIO *data);

static BIO_METHOD mem_method = {
	.type = BIO_TYPE_MEM,
	.name = "memory buffer",
	.bwrite = mem_write,
	.bread = mem_read,
	.bputs = mem_puts,
	.bgets = mem_gets,
	.ctrl = mem_ctrl,
	.create = mem_new,
	.destroy = mem_free
};

/* bio->num is used to hold the value to return on 'empty', if it is
 * 0, should_retry is not set */

BIO_METHOD *
BIO_s_mem(void)
{
	return (&mem_method);
}

BIO *
BIO_new_mem_buf(void *buf, int len)
{
	BIO *ret;
	BUF_MEM *b;
	size_t sz;

	if (!buf) {
		BIOerror(BIO_R_NULL_PARAMETER);
		return NULL;
	}
	sz = (len < 0) ? strlen(buf) : (size_t)len;
	if (!(ret = BIO_new(BIO_s_mem())))
		return NULL;
	b = (BUF_MEM *)ret->ptr;
	b->data = buf;
	b->length = sz;
	b->max = sz;
	ret->flags |= BIO_FLAGS_MEM_RDONLY;
	/* Since this is static data retrying wont help */
	ret->num = 0;
	return ret;
}

static int
mem_new(BIO *bi)
{
	BUF_MEM *b;

	if ((b = BUF_MEM_new()) == NULL)
		return (0);
	bi->shutdown = 1;
	bi->init = 1;
	bi->num = -1;
	bi->ptr = (char *)b;
	return (1);
}

static int
mem_free(BIO *a)
{
	if (a == NULL)
		return (0);
	if (a->shutdown) {
		if ((a->init) && (a->ptr != NULL)) {
			BUF_MEM *b;
			b = (BUF_MEM *)a->ptr;
			if (a->flags & BIO_FLAGS_MEM_RDONLY)
				b->data = NULL;
			BUF_MEM_free(b);
			a->ptr = NULL;
		}
	}
	return (1);
}

static int
mem_read(BIO *b, char *out, int outl)
{
	int ret = -1;
	BUF_MEM *bm;

	bm = (BUF_MEM *)b->ptr;
	BIO_clear_retry_flags(b);
	ret = (outl >=0 && (size_t)outl > bm->length) ? (int)bm->length : outl;
	if ((out != NULL) && (ret > 0)) {
		memcpy(out, bm->data, ret);
		bm->length -= ret;
		if (b->flags & BIO_FLAGS_MEM_RDONLY)
			bm->data += ret;
		else {
			memmove(&(bm->data[0]), &(bm->data[ret]), bm->length);
		}
	} else if (bm->length == 0) {
		ret = b->num;
		if (ret != 0)
			BIO_set_retry_read(b);
	}
	return (ret);
}

static int
mem_write(BIO *b, const char *in, int inl)
{
	int ret = -1;
	int blen;
	BUF_MEM *bm;

	bm = (BUF_MEM *)b->ptr;
	if (in == NULL) {
		BIOerror(BIO_R_NULL_PARAMETER);
		goto end;
	}

	if (b->flags & BIO_FLAGS_MEM_RDONLY) {
		BIOerror(BIO_R_WRITE_TO_READ_ONLY_BIO);
		goto end;
	}

	BIO_clear_retry_flags(b);
	blen = bm->length;
	if (BUF_MEM_grow_clean(bm, blen + inl) != (blen + inl))
		goto end;
	memcpy(&(bm->data[blen]), in, inl);
	ret = inl;
end:
	return (ret);
}

static long
mem_ctrl(BIO *b, int cmd, long num, void *ptr)
{
	long ret = 1;
	char **pptr;

	BUF_MEM *bm = (BUF_MEM *)b->ptr;

	switch (cmd) {
	case BIO_CTRL_RESET:
		if (bm->data != NULL) {
			/* For read only case reset to the start again */
			if (b->flags & BIO_FLAGS_MEM_RDONLY) {
				bm->data -= bm->max - bm->length;
				bm->length = bm->max;
			} else {
				memset(bm->data, 0, bm->max);
				bm->length = 0;
			}
		}
		break;
	case BIO_CTRL_EOF:
		ret = (long)(bm->length == 0);
		break;
	case BIO_C_SET_BUF_MEM_EOF_RETURN:
		b->num = (int)num;
		break;
	case BIO_CTRL_INFO:
		ret = (long)bm->length;
		if (ptr != NULL) {
			pptr = (char **)ptr;
			*pptr = (char *)&(bm->data[0]);
		}
		break;
	case BIO_C_SET_BUF_MEM:
		mem_free(b);
		b->shutdown = (int)num;
		b->ptr = ptr;
		break;
	case BIO_C_GET_BUF_MEM_PTR:
		if (ptr != NULL) {
			pptr = (char **)ptr;
			*pptr = (char *)bm;
		}
		break;
	case BIO_CTRL_GET_CLOSE:
		ret = (long)b->shutdown;
		break;
	case BIO_CTRL_SET_CLOSE:
		b->shutdown = (int)num;
		break;

	case BIO_CTRL_WPENDING:
		ret = 0L;
		break;
	case BIO_CTRL_PENDING:
		ret = (long)bm->length;
		break;
	case BIO_CTRL_DUP:
	case BIO_CTRL_FLUSH:
		ret = 1;
		break;
	case BIO_CTRL_PUSH:
	case BIO_CTRL_POP:
	default:
		ret = 0;
		break;
	}
	return (ret);
}

static int
mem_gets(BIO *bp, char *buf, int size)
{
	int i, j;
	int ret = -1;
	char *p;
	BUF_MEM *bm = (BUF_MEM *)bp->ptr;

	BIO_clear_retry_flags(bp);
	j = bm->length;
	if ((size - 1) < j)
		j = size - 1;
	if (j <= 0) {
		*buf = '\0';
		return 0;
	}
	p = bm->data;
	for (i = 0; i < j; i++) {
		if (p[i] == '\n') {
			i++;
			break;
		}
	}

	/*
	 * i is now the max num of bytes to copy, either j or up to
	 * and including the first newline
	 */ 

	i = mem_read(bp, buf, i);
	if (i > 0)
		buf[i] = '\0';
	ret = i;
	return (ret);
}

static int
mem_puts(BIO *bp, const char *str)
{
	int n, ret;

	n = strlen(str);
	ret = mem_write(bp, str, n);
	/* memory semantics is that it will always work */
	return (ret);
}
