path: root/lib/gnutls_str.c

/*
 * Copyright (C) 2002, 2004, 2005  Free Software Foundation
 *
 * Author: Nikos Mavroyanopoulos
 *
 * This file is part of GNUTLS.
 *
 * The GNUTLS 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.
 *
 * This 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 this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
 * USA
 *
 */

#include <gnutls_int.h>
#include <gnutls_errors.h>
#include <gnutls_num.h>
#include <gnutls_str.h>

/* These function are like strcat, strcpy. They only
 * do bound checking (they shouldn't cause buffer overruns),
 * and they always produce null terminated strings.
 *
 * They should be used only with null terminated strings.
 */
void _gnutls_str_cat(char *dest, size_t dest_tot_size, const char *src)
{
    size_t str_size = strlen(src);
    size_t dest_size = strlen(dest);

    if (dest_tot_size - dest_size > str_size) {
	strcat(dest, src);
    } else {
	if (dest_tot_size - dest_size > 0) {
	    strncat(dest, src, (dest_tot_size - dest_size) - 1);
	    dest[dest_tot_size - 1] = 0;
	}
    }
}

void _gnutls_str_cpy(char *dest, size_t dest_tot_size, const char *src)
{
    size_t str_size = strlen(src);

    if (dest_tot_size > str_size) {
	strcpy(dest, src);
    } else {
	if (dest_tot_size > 0) {
	    strncpy(dest, src, (dest_tot_size) - 1);
	    dest[dest_tot_size - 1] = 0;
	}
    }
}

void _gnutls_mem_cpy(char *dest, size_t dest_tot_size, const char *src,
		     size_t src_size)
{

    if (dest_tot_size >= src_size) {
	memcpy(dest, src, src_size);
    } else {
	if (dest_tot_size > 0) {
	    memcpy(dest, src, dest_tot_size);
	}
    }
}

void _gnutls_string_init(gnutls_string * str,
			 gnutls_alloc_function alloc_func,
			 gnutls_realloc_function realloc_func,
			 gnutls_free_function free_func)
{
    str->data = NULL;
    str->max_length = 0;
    str->length = 0;

    str->alloc_func = alloc_func;
    str->free_func = free_func;
    str->realloc_func = realloc_func;
}

void _gnutls_string_clear(gnutls_string * str)
{
    if (str == NULL || str->data == NULL)
	return;
    str->free_func(str->data);

    str->data = NULL;
    str->max_length = 0;
    str->length = 0;
}

/* This one does not copy the string.
 */
gnutls_datum_t _gnutls_string2datum(gnutls_string * str)
{
    gnutls_datum_t ret;

    ret.data = str->data;
    ret.size = str->length;

    return ret;
}

#define MIN_CHUNK 256

int _gnutls_string_copy_str(gnutls_string * dest, const char *src)
{
    size_t src_len = strlen(src);

    if (dest->max_length >= src_len) {
	memcpy(dest->data, src, src_len);
	dest->length = src_len;

	return src_len;
    } else {
	dest->data =
	    dest->realloc_func(dest->data, MAX(src_len, MIN_CHUNK));
	if (dest->data == NULL) {
	    gnutls_assert();
	    return GNUTLS_E_MEMORY_ERROR;
	}
	dest->max_length = MAX(MIN_CHUNK, src_len);

	memcpy(dest->data, src, src_len);
	dest->length = src_len;

	return src_len;
    }
}

int _gnutls_string_append_str(gnutls_string * dest, const char *src)
{
    size_t src_len = strlen(src);
    size_t tot_len = src_len + dest->length;

    if (dest->max_length >= tot_len) {
	memcpy(&dest->data[dest->length], src, src_len);
	dest->length = tot_len;

	return tot_len;
    } else {
	size_t new_len =
	    MAX(src_len, MIN_CHUNK) + MAX(dest->max_length, MIN_CHUNK);

	dest->data = dest->realloc_func(dest->data, new_len);
	if (dest->data == NULL) {
	    gnutls_assert();
	    return GNUTLS_E_MEMORY_ERROR;
	}
	dest->max_length = new_len;

	memcpy(&dest->data[dest->length], src, src_len);
	dest->length = tot_len;

	return tot_len;
    }
}

int _gnutls_string_append_data(gnutls_string * dest, const void *data,
			       size_t data_size)
{
    size_t tot_len = data_size + dest->length;

    if (dest->max_length >= tot_len) {
	memcpy(&dest->data[dest->length], data, data_size);
	dest->length = tot_len;

	return tot_len;
    } else {
	size_t new_len =
	    MAX(data_size, MIN_CHUNK) + MAX(dest->max_length, MIN_CHUNK);

	dest->data = dest->realloc_func(dest->data, new_len);
	if (dest->data == NULL) {
	    gnutls_assert();
	    return GNUTLS_E_MEMORY_ERROR;
	}
	dest->max_length = new_len;

	memcpy(&dest->data[dest->length], data, data_size);
	dest->length = tot_len;

	return tot_len;
    }
}

/* Converts the given string (old) to hex. A buffer must be provided
 * to hold the new hex string. The new string will be null terminated.
 * If the buffer does not have enough space to hold the string, a
 * truncated hex string is returned (always null terminated).
 */
char *_gnutls_bin2hex(const void *_old, size_t oldlen,
		      char *buffer, size_t buffer_size)
{
    unsigned int i, j;
    const opaque *old = _old;

    for (i = j = 0; i < oldlen && j + 2 < buffer_size; j += 2) {
	sprintf(&buffer[j], "%.2x", old[i]);
	i++;
    }
    buffer[j] = '\0';

    return buffer;
}

/* just a hex2bin function.
 */
int _gnutls_hex2bin(const opaque* hex_data, int hex_size, opaque * bin_data,
        size_t * bin_size)
{
int i, j;
opaque hex2_data[3];
unsigned long val;

   /* FIXME: we don't handle whitespace.
    */
   hex_size /= 2;

   if (*bin_size < (size_t)hex_size) {
     gnutls_assert();
     return GNUTLS_E_SHORT_MEMORY_BUFFER;
   }

   for (i=j=0; j < hex_size;i+=2,j++) {
      hex2_data[0] = hex_data[i];
      hex2_data[1] = hex_data[i+1];
      hex2_data[2] = 0;
      val = strtoul( (char*)hex2_data, NULL, 16);
      if (val == ULONG_MAX) {
         gnutls_assert();
         return GNUTLS_E_SRP_PWD_PARSING_ERROR;
      }
      bin_data[j] = val;
   }

   return 0;
}