D-Bus  1.14.10
dbus-marshal-byteswap.c
1 /* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */
2 /* dbus-marshal-byteswap.c Swap a block of marshaled data
3  *
4  * Copyright (C) 2005 Red Hat, Inc.
5  *
6  * Licensed under the Academic Free License version 2.1
7  *
8  * This program is free software; you can redistribute it and/or modify
9  * it under the terms of the GNU General Public License as published by
10  * the Free Software Foundation; either version 2 of the License, or
11  * (at your option) any later version.
12  *
13  * This program is distributed in the hope that it will be useful,
14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16  * GNU General Public License for more details.
17  *
18  * You should have received a copy of the GNU General Public License
19  * along with this program; if not, write to the Free Software
20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21  *
22  */
23 
24 #include <config.h>
25 #include "dbus-marshal-byteswap.h"
26 #include "dbus-marshal-basic.h"
27 #include "dbus-signature.h"
28 
34 static void
35 byteswap_body_helper (DBusTypeReader *reader,
36  dbus_bool_t walk_reader_to_end,
37  int old_byte_order,
38  int new_byte_order,
39  unsigned char *p,
40  unsigned char **new_p)
41 {
42  int current_type;
43 
44  while ((current_type = _dbus_type_reader_get_current_type (reader)) != DBUS_TYPE_INVALID)
45  {
46  switch (current_type)
47  {
48  case DBUS_TYPE_BYTE:
49  ++p;
50  break;
51 
52  case DBUS_TYPE_INT16:
53  case DBUS_TYPE_UINT16:
54  {
55  p = _DBUS_ALIGN_ADDRESS (p, 2);
56  *((dbus_uint16_t*)p) = DBUS_UINT16_SWAP_LE_BE (*((dbus_uint16_t*)p));
57  p += 2;
58  }
59  break;
60 
61  case DBUS_TYPE_BOOLEAN:
62  case DBUS_TYPE_INT32:
63  case DBUS_TYPE_UINT32:
64  case DBUS_TYPE_UNIX_FD:
65  {
66  p = _DBUS_ALIGN_ADDRESS (p, 4);
67  *((dbus_uint32_t*)p) = DBUS_UINT32_SWAP_LE_BE (*((dbus_uint32_t*)p));
68  p += 4;
69  }
70  break;
71 
72  case DBUS_TYPE_INT64:
73  case DBUS_TYPE_UINT64:
74  case DBUS_TYPE_DOUBLE:
75  {
76  p = _DBUS_ALIGN_ADDRESS (p, 8);
77  *((dbus_uint64_t*)p) = DBUS_UINT64_SWAP_LE_BE (*((dbus_uint64_t*)p));
78  p += 8;
79  }
80  break;
81 
82  case DBUS_TYPE_ARRAY:
83  case DBUS_TYPE_STRING:
85  {
86  dbus_uint32_t array_len;
87 
88  p = _DBUS_ALIGN_ADDRESS (p, 4);
89 
90  array_len = _dbus_unpack_uint32 (old_byte_order, p);
91 
92  *((dbus_uint32_t*)p) = DBUS_UINT32_SWAP_LE_BE (*((dbus_uint32_t*)p));
93  p += 4;
94 
95  if (current_type == DBUS_TYPE_ARRAY)
96  {
97  int elem_type;
98  int alignment;
99 
100  elem_type = _dbus_type_reader_get_element_type (reader);
101  alignment = _dbus_type_get_alignment (elem_type);
102 
103  _dbus_assert ((array_len / alignment) < DBUS_MAXIMUM_ARRAY_LENGTH);
104 
105  p = _DBUS_ALIGN_ADDRESS (p, alignment);
106 
107  if (dbus_type_is_fixed (elem_type))
108  {
109  if (alignment > 1)
110  _dbus_swap_array (p, array_len / alignment, alignment);
111  p += array_len;
112  }
113  else
114  {
115  DBusTypeReader sub;
116  const unsigned char *array_end;
117 
118  array_end = p + array_len;
119 
120  _dbus_type_reader_recurse (reader, &sub);
121 
122  while (p < array_end)
123  {
124  byteswap_body_helper (&sub,
125  FALSE,
126  old_byte_order,
127  new_byte_order,
128  p, &p);
129  }
130  }
131  }
132  else
133  {
134  _dbus_assert (current_type == DBUS_TYPE_STRING ||
135  current_type == DBUS_TYPE_OBJECT_PATH);
136 
137  p += (array_len + 1); /* + 1 for nul */
138  }
139  }
140  break;
141 
142  case DBUS_TYPE_SIGNATURE:
143  {
144  dbus_uint32_t sig_len;
145 
146  sig_len = *p;
147 
148  p += (sig_len + 2); /* +2 for len and nul */
149  }
150  break;
151 
152  case DBUS_TYPE_VARIANT:
153  {
154  /* 1 byte sig len, sig typecodes, align to
155  * contained-type-boundary, values.
156  */
157  dbus_uint32_t sig_len;
158  DBusString sig;
159  DBusTypeReader sub;
160  int contained_alignment;
161 
162  sig_len = *p;
163  ++p;
164 
165  _dbus_string_init_const_len (&sig, (const char *) p, sig_len);
166 
167  p += (sig_len + 1); /* 1 for nul */
168 
169  contained_alignment = _dbus_type_get_alignment (_dbus_first_type_in_signature (&sig, 0));
170 
171  p = _DBUS_ALIGN_ADDRESS (p, contained_alignment);
172 
173  _dbus_type_reader_init_types_only (&sub, &sig, 0);
174 
175  byteswap_body_helper (&sub, FALSE, old_byte_order, new_byte_order, p, &p);
176  }
177  break;
178 
179  case DBUS_TYPE_STRUCT:
181  {
182  DBusTypeReader sub;
183 
184  p = _DBUS_ALIGN_ADDRESS (p, 8);
185 
186  _dbus_type_reader_recurse (reader, &sub);
187 
188  byteswap_body_helper (&sub, TRUE, old_byte_order, new_byte_order, p, &p);
189  }
190  break;
191 
192  default:
193  _dbus_assert_not_reached ("invalid typecode in supposedly-validated signature");
194  break;
195  }
196 
197  if (walk_reader_to_end)
198  _dbus_type_reader_next (reader);
199  else
200  break;
201  }
202 
203  if (new_p)
204  *new_p = p;
205 }
206 
217 void
219  int signature_start,
220  int old_byte_order,
221  int new_byte_order,
222  DBusString *value_str,
223  int value_pos)
224 {
225  DBusTypeReader reader;
226 
227  _dbus_assert (value_pos >= 0);
228  _dbus_assert (value_pos <= _dbus_string_get_length (value_str));
229 
230  if (old_byte_order == new_byte_order)
231  return;
232 
234  signature, signature_start);
235 
236  byteswap_body_helper (&reader, TRUE,
237  old_byte_order, new_byte_order,
238  _dbus_string_get_udata_len (value_str, value_pos, 0),
239  NULL);
240 }
241 
244 /* Tests in dbus-marshal-byteswap-util.c */
#define _dbus_assert_not_reached(explanation)
Aborts with an error message if called.
#define _dbus_assert(condition)
Aborts with an error message if the condition is false.
#define NULL
A null pointer, defined appropriately for C or C++.
#define TRUE
Expands to "1".
#define FALSE
Expands to "0".
void _dbus_type_reader_recurse(DBusTypeReader *reader, DBusTypeReader *sub)
Initialize a new reader pointing to the first type and corresponding value that's a child of the curr...
int _dbus_type_get_alignment(int typecode)
Gets the alignment requirement for the given type; will be 1, 4, or 8.
void _dbus_type_reader_init_types_only(DBusTypeReader *reader, const DBusString *type_str, int type_pos)
Like _dbus_type_reader_init() but the iteration is over the signature, not over values.
dbus_uint32_t _dbus_unpack_uint32(int byte_order, const unsigned char *data)
Unpacks a 32 bit unsigned integer from a data pointer.
int _dbus_first_type_in_signature(const DBusString *str, int pos)
Get the first type in the signature.
void _dbus_marshal_byteswap(const DBusString *signature, int signature_start, int old_byte_order, int new_byte_order, DBusString *value_str, int value_pos)
Byteswaps the marshaled data in the given value_str.
int _dbus_type_reader_get_element_type(const DBusTypeReader *reader)
Gets the type of an element of the array the reader is currently pointing to.
dbus_bool_t _dbus_type_reader_next(DBusTypeReader *reader)
Skip to the next value on this "level".
int _dbus_type_reader_get_current_type(const DBusTypeReader *reader)
Gets the type of the value the reader is currently pointing to; or for a types-only reader gets the t...
void _dbus_swap_array(unsigned char *data, int n_elements, int alignment)
Swaps the elements of an array to the opposite byte order.
#define DBUS_TYPE_SIGNATURE
Type code marking a D-Bus type signature.
#define DBUS_TYPE_OBJECT_PATH
Type code marking a D-Bus object path.
#define DBUS_TYPE_BYTE
Type code marking an 8-bit unsigned integer.
Definition: dbus-protocol.h:66
#define DBUS_TYPE_INT16
Type code marking a 16-bit signed integer.
Definition: dbus-protocol.h:74
#define DBUS_TYPE_VARIANT
Type code marking a D-Bus variant type.
#define DBUS_MAXIMUM_ARRAY_LENGTH
Max length of a marshaled array in bytes (64M, 2^26) We use signed int for lengths so must be INT_MAX...
#define DBUS_TYPE_INT32
Type code marking a 32-bit signed integer.
Definition: dbus-protocol.h:82
#define DBUS_TYPE_UNIX_FD
Type code marking a unix file descriptor.
#define DBUS_TYPE_BOOLEAN
Type code marking a boolean.
Definition: dbus-protocol.h:70
#define DBUS_TYPE_STRING
Type code marking a UTF-8 encoded, nul-terminated Unicode string.
#define DBUS_TYPE_ARRAY
Type code marking a D-Bus array type.
#define DBUS_TYPE_INVALID
Type code that is never equal to a legitimate type code.
Definition: dbus-protocol.h:60
#define DBUS_TYPE_INT64
Type code marking a 64-bit signed integer.
Definition: dbus-protocol.h:90
#define DBUS_TYPE_DOUBLE
Type code marking an 8-byte double in IEEE 754 format.
Definition: dbus-protocol.h:98
#define DBUS_TYPE_UINT64
Type code marking a 64-bit unsigned integer.
Definition: dbus-protocol.h:94
#define DBUS_TYPE_DICT_ENTRY
Type code used to represent a dict entry; however, this type code does not appear in type signatures,...
#define DBUS_TYPE_UINT16
Type code marking a 16-bit unsigned integer.
Definition: dbus-protocol.h:78
#define DBUS_TYPE_STRUCT
STRUCT and DICT_ENTRY are sort of special since their codes can't appear in a type string,...
#define DBUS_TYPE_UINT32
Type code marking a 32-bit unsigned integer.
Definition: dbus-protocol.h:86
dbus_bool_t dbus_type_is_fixed(int typecode)
Tells you whether values of this type can change length if you set them to some other value.
void _dbus_string_init_const_len(DBusString *str, const char *value, int len)
Initializes a constant string with a length.
Definition: dbus-string.c:217
dbus_uint32_t dbus_bool_t
A boolean, valid values are TRUE and FALSE.
Definition: dbus-types.h:35
The type reader is an iterator for reading values from a block of values.