/*

 * string.c - ssh string functions

 *

 * This file is part of the SSH Library

 *

 * Copyright (c) 2003-2008 by Aris Adamantiadis

 *

 * The SSH Library is free software; you can redistribute it and/or modify

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

 * the Free Software Foundation; either version 2.1 of the License, or (at your

 * option) any later version.

 *

 * The SSH Library 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 Lesser General Public

 * License for more details.

 *

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

 * along with the SSH Library; see the file COPYING.  If not, write to

 * the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,

 * MA 02111-1307, USA.

 */

#include "config.h"

#include <errno.h>

#include <limits.h>

#ifndef _WIN32

#include <netinet/in.h>

#include <arpa/inet.h>

#endif

#include "libssh/priv.h"

#include "libssh/string.h"

/* String maximum size is 256M */

#define STRING_SIZE_MAX 0x10000000

/**

 * @defgroup libssh_string The SSH string functions

 * @ingroup libssh

 *

 * @brief String manipulations used in libssh.

 *

 * @{

 */

/**

 * @brief Create a new SSH String object.

 *

 * @param[in] size       The size of the string.

 *

 * @return               The newly allocated string, NULL on error.

 */

struct ssh_string_struct *ssh_string_new(size_t size)

{

    struct ssh_string_struct *str = NULL;

    if (size > STRING_SIZE_MAX) {

        errno = EINVAL;

        return NULL;

    }

    str = malloc(sizeof(struct ssh_string_struct) + size);

    if (str == NULL) {

        return NULL;

    }

    str->size = htonl(size);

    str->data[0] = 0;

    return str;

}

/**

 * @brief Fill a string with given data. The string should be big enough.

 *

 * @param s        An allocated string to fill with data.

 *

 * @param data     The data to fill the string with.

 *

 * @param len      Size of data.

 *

 * @return         0 on success, < 0 on error.

 */

int ssh_string_fill(struct ssh_string_struct *s, const void *data, size_t len) {

  if ((s == NULL) || (data == NULL) ||

      (len == 0) || (len > ssh_string_len(s))) {

    return -1;

  }

  memcpy(s->data, data, len);

  return 0;

}

/**

 * @brief Create a ssh string using a C string

 *

 * @param[in] what      The source 0-terminated C string.

 *

 * @return              The newly allocated string, NULL on error with errno

 *                      set.

 *

 * @note The nul byte is not copied nor counted in the ouput string.

 */

struct ssh_string_struct *ssh_string_from_char(const char *what) {

  struct ssh_string_struct *ptr;

  size_t len;

  if(what == NULL) {

      errno = EINVAL;

      return NULL;

  }

  len = strlen(what);

  ptr = ssh_string_new(len);

  if (ptr == NULL) {

    return NULL;

  }

  memcpy(ptr->data, what, len);

  return ptr;

}

/**

 * @brief Return the size of a SSH string.

 *

 * @param[in] s         The the input SSH string.

 *

 * @return The size of the content of the string, 0 on error.

 */

size_t ssh_string_len(struct ssh_string_struct *s) {

    size_t size;

    if (s == NULL) {

        return 0;

    }

    size = ntohl(s->size);

    if (size > 0 && size <= STRING_SIZE_MAX) {

        return size;

    }

    return 0;

}

/**

 * @brief Get the the string as a C nul-terminated string.

 *

 * This is only available as long as the SSH string exists.

 *

 * @param[in] s         The SSH string to get the C string from.

 *

 * @return              The char pointer, NULL on error.

 */

const char *ssh_string_get_char(struct ssh_string_struct *s)

{

    if (s == NULL) {

        return NULL;

    }

    s->data[ssh_string_len(s)] = '\0';

    return (const char *) s->data;

}

/**

 * @brief Convert a SSH string to a C nul-terminated string.

 *

 * @param[in] s         The SSH input string.

 *

 * @return              An allocated string pointer, NULL on error with errno

 *                      set.

 *

 * @note If the input SSH string contains zeroes, some parts of the output

 * string may not be readable with regular libc functions.

 */

char *ssh_string_to_char(struct ssh_string_struct *s) {

  size_t len;

  char *new;

  if (s == NULL) {

      return NULL;

  }

  len = ssh_string_len(s);

  if (len + 1 < len) {

    return NULL;

  }

  new = malloc(len + 1);

  if (new == NULL) {

    return NULL;

  }

  memcpy(new, s->data, len);

  new[len] = '\0';

  return new;

}

/**

 * @brief Deallocate a char string object.

 *

 * @param[in] s         The string to delete.

 */

void ssh_string_free_char(char *s) {

    SAFE_FREE(s);

}

/**

 * @brief Copy a string, return a newly allocated string. The caller has to

 *        free the string.

 *

 * @param[in] s         String to copy.

 *

 * @return              Newly allocated copy of the string, NULL on error.

 */

struct ssh_string_struct *ssh_string_copy(struct ssh_string_struct *s) {

  struct ssh_string_struct *new;

  size_t len;

  if (s == NULL) {

      return NULL;

  }

  len = ssh_string_len(s);

  if (len == 0) {

      return NULL;

  }

  new = ssh_string_new(len);

  if (new == NULL) {

    return NULL;

  }

  memcpy(new->data, s->data, len);

  return new;

}

/**

 * @brief Destroy the data in a string so it couldn't appear in a core dump.

 *

 * @param[in] s         The string to burn.

 */

void ssh_string_burn(struct ssh_string_struct *s) {

    if (s == NULL || s->size == 0) {

        return;

    }

    explicit_bzero(s->data, ssh_string_len(s));

}

/**

 * @brief Get the payload of the string.

 *

 * @param s             The string to get the data from.

 *

 * @return              Return the data of the string or NULL on error.

 */

void *ssh_string_data(struct ssh_string_struct *s) {

  if (s == NULL) {

    return NULL;

  }

  return s->data;

}

/**

 * @brief Deallocate a SSH string object.

 *

 * \param[in] s         The SSH string to delete.

 */

void ssh_string_free(struct ssh_string_struct *s) {

  SAFE_FREE(s);

}

/** @} */