/* $OpenBSD: bss_mem.c,v 1.21 2022/02/19 15:59:12 jsing 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 <limits.h>

#include <stdio.h>

#include <string.h>

#include <openssl/bio.h>

#include <openssl/err.h>

#include <openssl/buffer.h>

#include "bio_local.h"

struct bio_mem {

  BUF_MEM *buf;

  size_t read_offset;

};

static size_t

bio_mem_pending(struct bio_mem *bm)

{

  if (bm->read_offset > bm->buf->length)

    return 0;

  return bm->buf->length - bm->read_offset;

}

static uint8_t *

bio_mem_read_ptr(struct bio_mem *bm)

{

  return &bm->buf->data[bm->read_offset];

}

static int mem_new(BIO *bio);

static int mem_free(BIO *bio);

static int mem_write(BIO *bio, const char *in, int in_len);

static int mem_read(BIO *bio, char *out, int out_len);

static int mem_puts(BIO *bio, const char *in);

static int mem_gets(BIO *bio, char *out, int out_len);

static long mem_ctrl(BIO *bio, int cmd, long arg1, void *arg2);

static const 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.

 */

const BIO_METHOD *

BIO_s_mem(void)

{

  return &mem_method;

}

BIO *

BIO_new_mem_buf(const void *buf, int buf_len)

{

  struct bio_mem *bm;

  BIO *bio;

  if (buf == NULL) {

    BIOerror(BIO_R_NULL_PARAMETER);

    return NULL;

  }

  if (buf_len == -1)

    buf_len = strlen(buf);

  if (buf_len < 0) {

    BIOerror(BIO_R_INVALID_ARGUMENT);

    return NULL;

  }

  if ((bio = BIO_new(BIO_s_mem())) == NULL)

    return NULL;

  bm = bio->ptr;

  bm->buf->data = (void *)buf; /* Trust in the BIO_FLAGS_MEM_RDONLY flag. */

  bm->buf->length = buf_len;

  bm->buf->max = buf_len;

  bio->flags |= BIO_FLAGS_MEM_RDONLY;

  /* Since this is static data retrying will not help. */

  bio->num = 0;

  return bio;

}

static int

mem_new(BIO *bio)

{

  struct bio_mem *bm;

  if ((bm = calloc(1, sizeof(*bm))) == NULL)

    return 0;

  if ((bm->buf = BUF_MEM_new()) == NULL) {

    free(bm);

    return 0;

  }

  bio->shutdown = 1;

  bio->init = 1;

  bio->num = -1;

  bio->ptr = bm;

  return 1;

}

static int

mem_free(BIO *bio)

{

  struct bio_mem *bm;

  if (bio == NULL)

    return 0;

  if (!bio->init || bio->ptr == NULL)

    return 1;

  bm = bio->ptr;

  if (bio->shutdown) {

    if (bio->flags & BIO_FLAGS_MEM_RDONLY)

      bm->buf->data = NULL;

    BUF_MEM_free(bm->buf);

  }

  free(bm);

  bio->ptr = NULL;

  return 1;

}

static int

mem_read(BIO *bio, char *out, int out_len)

{

  struct bio_mem *bm = bio->ptr;

  BIO_clear_retry_flags(bio);

  if (out == NULL || out_len <= 0)

    return 0;

  if ((size_t)out_len > bio_mem_pending(bm))

    out_len = bio_mem_pending(bm);

  if (out_len == 0) {

    if (bio->num != 0)

      BIO_set_retry_read(bio);

    return bio->num;

  }

  memcpy(out, bio_mem_read_ptr(bm), out_len);

  bm->read_offset += out_len;

  return out_len;

}

static int

mem_write(BIO *bio, const char *in, int in_len)

{

  struct bio_mem *bm = bio->ptr;

  size_t buf_len;

  BIO_clear_retry_flags(bio);

  if (in == NULL || in_len <= 0)

    return 0;

  if (bio->flags & BIO_FLAGS_MEM_RDONLY) {

    BIOerror(BIO_R_WRITE_TO_READ_ONLY_BIO);

    return -1;

  }

  if (bm->read_offset > 4096) {

    memmove(bm->buf->data, bio_mem_read_ptr(bm),

        bio_mem_pending(bm));

    bm->buf->length = bio_mem_pending(bm);

    bm->read_offset = 0;

  }

  /*

   * Check for overflow and ensure we do not exceed an int, otherwise we

   * cannot tell if BUF_MEM_grow_clean() succeeded.

   */

  buf_len = bm->buf->length + in_len;

  if (buf_len < bm->buf->length || buf_len > INT_MAX)

    return -1;

  if (BUF_MEM_grow_clean(bm->buf, buf_len) != buf_len)

    return -1;

  memcpy(&bm->buf->data[buf_len - in_len], in, in_len);

  return in_len;

}

static long

mem_ctrl(BIO *bio, int cmd, long num, void *ptr)

{

  struct bio_mem *bm = bio->ptr;

  void **pptr;

  long ret = 1;

  switch (cmd) {

  case BIO_CTRL_RESET:

    if (bm->buf->data != NULL) {

      if (!(bio->flags & BIO_FLAGS_MEM_RDONLY)) {

        memset(bm->buf->data, 0, bm->buf->max);

        bm->buf->length = 0;

      }

      bm->read_offset = 0;

    }

    break;

  case BIO_CTRL_EOF:

    ret = (long)(bio_mem_pending(bm) == 0);

    break;

  case BIO_C_SET_BUF_MEM_EOF_RETURN:

    bio->num = (int)num;

    break;

  case BIO_CTRL_INFO:

    if (ptr != NULL) {

      pptr = (void **)ptr;

      *pptr = bio_mem_read_ptr(bm);

    }

    ret = (long)bio_mem_pending(bm);

    break;

  case BIO_C_SET_BUF_MEM:

    BUF_MEM_free(bm->buf);

    bio->shutdown = (int)num;

    bm->buf = ptr;

    bm->read_offset = 0;

    break;

  case BIO_C_GET_BUF_MEM_PTR:

    if (ptr != NULL) {

      pptr = (void **)ptr;

      *pptr = bm->buf;

    }

    break;

  case BIO_CTRL_GET_CLOSE:

    ret = (long)bio->shutdown;

    break;

  case BIO_CTRL_SET_CLOSE:

    bio->shutdown = (int)num;

    break;

  case BIO_CTRL_WPENDING:

    ret = 0L;

    break;

  case BIO_CTRL_PENDING:

    ret = (long)bio_mem_pending(bm);

    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 *bio, char *out, int out_len)

{

  struct bio_mem *bm = bio->ptr;

  int i, out_max;

  char *p;

  int ret = -1;

  BIO_clear_retry_flags(bio);

  out_max = bio_mem_pending(bm);

  if (out_len - 1 < out_max)

    out_max = out_len - 1;

  if (out_max <= 0) {

    *out = '\0';

    return 0;

  }

  p = bio_mem_read_ptr(bm);

  for (i = 0; i < out_max; i++) {

    if (p[i] == '\n') {

      i++;

      break;

    }

  }

  /*

   * i is now the max num of bytes to copy, either out_max or up to and

   * including the first newline

   */ 

  if ((ret = mem_read(bio, out, i)) > 0)

    out[ret] = '\0';

  return ret;

}

static int

mem_puts(BIO *bio, const char *in)

{

  return mem_write(bio, in, strlen(in));

}