dbus-marshal-byteswap.c
/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */
/* dbus-marshal-byteswap.c Swap a block of marshaled data
*
* Copyright (C) 2005 Red Hat, Inc.
*
* Licensed under the Academic Free License version 2.1
*
* 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 2 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, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*
*/
#include <config.h>
#include "dbus-marshal-byteswap.h"
#include "dbus-marshal-basic.h"
#include "dbus-signature.h"
static void
byteswap_body_helper (DBusTypeReader *reader,
dbus_bool_t walk_reader_to_end,
int old_byte_order,
int new_byte_order,
unsigned char *p,
unsigned char **new_p)
{
int current_type;
while ((current_type = _dbus_type_reader_get_current_type (reader)) != DBUS_TYPE_INVALID)
{
switch (current_type)
{
case DBUS_TYPE_BYTE:
++p;
break;
case DBUS_TYPE_INT16:
case DBUS_TYPE_UINT16:
{
p = _DBUS_ALIGN_ADDRESS (p, 2);
*((dbus_uint16_t*)p) = DBUS_UINT16_SWAP_LE_BE (*((dbus_uint16_t*)p));
p += 2;
}
break;
case DBUS_TYPE_BOOLEAN:
case DBUS_TYPE_INT32:
case DBUS_TYPE_UINT32:
{
p = _DBUS_ALIGN_ADDRESS (p, 4);
*((dbus_uint32_t*)p) = DBUS_UINT32_SWAP_LE_BE (*((dbus_uint32_t*)p));
p += 4;
}
break;
case DBUS_TYPE_INT64:
case DBUS_TYPE_UINT64:
case DBUS_TYPE_DOUBLE:
{
p = _DBUS_ALIGN_ADDRESS (p, 8);
#ifdef DBUS_HAVE_INT64
*((dbus_uint64_t*)p) = DBUS_UINT64_SWAP_LE_BE (*((dbus_uint64_t*)p));
#else
_dbus_swap_array (p, 1, 8);
#endif
p += 8;
}
break;
case DBUS_TYPE_ARRAY:
case DBUS_TYPE_STRING:
case DBUS_TYPE_OBJECT_PATH:
{
dbus_uint32_t array_len;
p = _DBUS_ALIGN_ADDRESS (p, 4);
array_len = _dbus_unpack_uint32 (old_byte_order, p);
*((dbus_uint32_t*)p) = DBUS_UINT32_SWAP_LE_BE (*((dbus_uint32_t*)p));
p += 4;
if (current_type == DBUS_TYPE_ARRAY)
{
int elem_type;
int alignment;
elem_type = _dbus_type_reader_get_element_type (reader);
alignment = _dbus_type_get_alignment (elem_type);
_dbus_assert ((array_len / alignment) < DBUS_MAXIMUM_ARRAY_LENGTH);
p = _DBUS_ALIGN_ADDRESS (p, alignment);
if (dbus_type_is_fixed (elem_type))
{
if (alignment > 1)
_dbus_swap_array (p, array_len / alignment, alignment);
p += array_len;
}
else
{
DBusTypeReader sub;
const unsigned char *array_end;
array_end = p + array_len;
_dbus_type_reader_recurse (reader, &sub);
while (p < array_end)
{
byteswap_body_helper (&sub,
FALSE,
old_byte_order,
new_byte_order,
p, &p);
}
}
}
else
{
_dbus_assert (current_type == DBUS_TYPE_STRING ||
current_type == DBUS_TYPE_OBJECT_PATH);
p += (array_len + 1); /* + 1 for nul */
}
}
break;
case DBUS_TYPE_SIGNATURE:
{
dbus_uint32_t sig_len;
sig_len = *p;
p += (sig_len + 2); /* +2 for len and nul */
}
break;
case DBUS_TYPE_VARIANT:
{
/* 1 byte sig len, sig typecodes, align to
* contained-type-boundary, values.
*/
dbus_uint32_t sig_len;
DBusString sig;
DBusTypeReader sub;
int contained_alignment;
sig_len = *p;
++p;
_dbus_string_init_const_len (&sig, p, sig_len);
p += (sig_len + 1); /* 1 for nul */
contained_alignment = _dbus_type_get_alignment (_dbus_first_type_in_signature (&sig, 0));
p = _DBUS_ALIGN_ADDRESS (p, contained_alignment);
_dbus_type_reader_init_types_only (&sub, &sig, 0);
byteswap_body_helper (&sub, FALSE, old_byte_order, new_byte_order, p, &p);
}
break;
case DBUS_TYPE_STRUCT:
case DBUS_TYPE_DICT_ENTRY:
{
DBusTypeReader sub;
p = _DBUS_ALIGN_ADDRESS (p, 8);
_dbus_type_reader_recurse (reader, &sub);
byteswap_body_helper (&sub, TRUE, old_byte_order, new_byte_order, p, &p);
}
break;
case DBUS_TYPE_UNIX_FD:
/* fds can only be passed on a local machine, so byte order must always match */
_dbus_assert_not_reached("attempted to byteswap unix fds which makes no sense");
break;
default:
_dbus_assert_not_reached ("invalid typecode in supposedly-validated signature");
break;
}
if (walk_reader_to_end)
_dbus_type_reader_next (reader);
else
break;
}
if (new_p)
*new_p = p;
}
void
_dbus_marshal_byteswap (const DBusString *signature,
int signature_start,
int old_byte_order,
int new_byte_order,
DBusString *value_str,
int value_pos)
{
DBusTypeReader reader;
_dbus_assert (value_pos >= 0);
_dbus_assert (value_pos <= _dbus_string_get_length (value_str));
if (old_byte_order == new_byte_order)
return;
_dbus_type_reader_init_types_only (&reader,
signature, signature_start);
byteswap_body_helper (&reader, TRUE,
old_byte_order, new_byte_order,
_dbus_string_get_data_len (value_str, value_pos, 0),
NULL);
}
/* Tests in dbus-marshal-byteswap-util.c */