/*

   Unix SMB/CIFS implementation.

   SMB Extended attribute buffer handling

   Copyright (C) Jeremy Allison                 2005-2013

   Copyright (C) Tim Prouty     2008

   This program is free software; you can redistribute it and/or modify

   it under the terms of the GNU General Public License as published by

   the Free Software Foundation; either version 3 of the License, or

   (at your option) any later version.

   This program is distributed in the hope that it will be useful,

   but WITHOUT ANY WARRANTY; without even the implied warranty of

   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License

   along with this program.  If not, see <http://www.gnu.org/licenses/>.

*/

#include "includes.h"

#include "lib/util_ea.h"

/****************************************************************************

 Read one EA list entry from the buffer.

****************************************************************************/

struct ea_list *read_ea_list_entry(TALLOC_CTX *ctx, const char *pdata, size_t data_size, size_t *pbytes_used)

{

  struct ea_list *eal = talloc_zero(ctx, struct ea_list);

  uint16_t val_len;

  unsigned int namelen;

  size_t converted_size;

  if (!eal) {

    goto fail;

  }

  if (data_size < 6) {

    goto fail;

  }

  eal->ea.flags = CVAL(pdata,0);

  namelen = CVAL(pdata,1);

  val_len = SVAL(pdata,2);

  if (4 + namelen + 1 + val_len > data_size) {

    goto fail;

  }

  /* Ensure the name is null terminated. */

  if (pdata[namelen + 4] != '\0') {

    goto fail;

  }

  if (!pull_ascii_talloc(ctx, &eal->ea.name, pdata + 4, &converted_size)) {

    DBG_ERR("pull_ascii_talloc failed: %s\n", strerror(errno));

  }

  if (!eal->ea.name) {

    goto fail;

  }

  eal->ea.value = data_blob_talloc(eal, NULL, (size_t)val_len + 1);

  if (!eal->ea.value.data) {

    goto fail;

  }

  memcpy(eal->ea.value.data, pdata + 4 + namelen + 1, val_len);

  /* Ensure we're null terminated just in case we print the value. */

  eal->ea.value.data[val_len] = '\0';

  /* But don't count the null. */

  eal->ea.value.length--;

  if (pbytes_used) {

    *pbytes_used = 4 + namelen + 1 + val_len;

  }

  DBG_DEBUG("read ea name %s\n", eal->ea.name);

  dump_data(10, eal->ea.value.data, eal->ea.value.length);

  return eal;

fail:

  TALLOC_FREE(eal);

  return NULL;

}

/****************************************************************************

 Read a list of EA names and data from an incoming data buffer. Create an ea_list with them.

****************************************************************************/

struct ea_list *read_nttrans_ea_list(TALLOC_CTX *ctx, const char *pdata, size_t data_size)

{

  struct ea_list *ea_list_head = NULL;

  size_t offset = 0;

  if (data_size < 4) {

    return NULL;

  }

  while (offset + 4 <= data_size) {

    size_t next_offset = IVAL(pdata,offset);

    struct ea_list *eal = read_ea_list_entry(ctx, pdata + offset + 4, data_size - offset - 4, NULL);

    if (!eal) {

      return NULL;

    }

    DLIST_ADD_END(ea_list_head, eal);

    if (next_offset == 0) {

      break;

    }

    /* Integer wrap protection for the increment. */

    if (offset + next_offset < offset) {

      break;

    }

    offset += next_offset;

    /* Integer wrap protection for while loop. */

    if (offset + 4 < offset) {

      break;

    }

  }

  return ea_list_head;

}