D-Bus 1.15.0
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
34static void
35byteswap_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:
54 {
55 p = _DBUS_ALIGN_ADDRESS (p, 2);
56 *((dbus_uint16_t *) (void *) p) =
57 DBUS_UINT16_SWAP_LE_BE (*((dbus_uint16_t *) (void *) p));
58 p += 2;
59 }
60 break;
61
63 case DBUS_TYPE_INT32:
65 {
66 p = _DBUS_ALIGN_ADDRESS (p, 4);
67 *((dbus_uint32_t *) (void *) p) =
68 DBUS_UINT32_SWAP_LE_BE (*((dbus_uint32_t *) (void *) p));
69 p += 4;
70 }
71 break;
72
73 case DBUS_TYPE_INT64:
76 {
77 p = _DBUS_ALIGN_ADDRESS (p, 8);
78 *((dbus_uint64_t *) (void *) p) =
79 DBUS_UINT64_SWAP_LE_BE (*((dbus_uint64_t *) (void *) p));
80 p += 8;
81 }
82 break;
83
84 case DBUS_TYPE_ARRAY:
87 {
88 dbus_uint32_t array_len;
89
90 p = _DBUS_ALIGN_ADDRESS (p, 4);
91
92 array_len = _dbus_unpack_uint32 (old_byte_order, p);
93
94 *((dbus_uint32_t *) (void *) p) =
95 DBUS_UINT32_SWAP_LE_BE (*((dbus_uint32_t *) (void *) p));
96 p += 4;
97
98 if (current_type == DBUS_TYPE_ARRAY)
99 {
100 int elem_type;
101 int alignment;
102
103 elem_type = _dbus_type_reader_get_element_type (reader);
104 alignment = _dbus_type_get_alignment (elem_type);
105
106 _dbus_assert ((array_len / alignment) < DBUS_MAXIMUM_ARRAY_LENGTH);
107
108 p = _DBUS_ALIGN_ADDRESS (p, alignment);
109
110 if (dbus_type_is_fixed (elem_type))
111 {
112 if (alignment > 1)
113 _dbus_swap_array (p, array_len / alignment, alignment);
114 p += array_len;
115 }
116 else
117 {
118 DBusTypeReader sub;
119 const unsigned char *array_end;
120
121 array_end = p + array_len;
122
123 _dbus_type_reader_recurse (reader, &sub);
124
125 while (p < array_end)
126 {
127 byteswap_body_helper (&sub,
128 FALSE,
129 old_byte_order,
130 new_byte_order,
131 p, &p);
132 }
133 }
134 }
135 else
136 {
137 _dbus_assert (current_type == DBUS_TYPE_STRING ||
138 current_type == DBUS_TYPE_OBJECT_PATH);
139
140 p += (array_len + 1); /* + 1 for nul */
141 }
142 }
143 break;
144
146 {
147 dbus_uint32_t sig_len;
148
149 sig_len = *p;
150
151 p += (sig_len + 2); /* +2 for len and nul */
152 }
153 break;
154
156 {
157 /* 1 byte sig len, sig typecodes, align to
158 * contained-type-boundary, values.
159 */
160 dbus_uint32_t sig_len;
161 DBusString sig;
162 DBusTypeReader sub;
163 int contained_alignment;
164
165 sig_len = *p;
166 ++p;
167
168 _dbus_string_init_const_len (&sig, (const char *) p, sig_len);
169
170 p += (sig_len + 1); /* 1 for nul */
171
172 contained_alignment = _dbus_type_get_alignment (_dbus_first_type_in_signature (&sig, 0));
173
174 p = _DBUS_ALIGN_ADDRESS (p, contained_alignment);
175
176 _dbus_type_reader_init_types_only (&sub, &sig, 0);
177
178 byteswap_body_helper (&sub, FALSE, old_byte_order, new_byte_order, p, &p);
179 }
180 break;
181
182 case DBUS_TYPE_STRUCT:
184 {
185 DBusTypeReader sub;
186
187 p = _DBUS_ALIGN_ADDRESS (p, 8);
188
189 _dbus_type_reader_recurse (reader, &sub);
190
191 byteswap_body_helper (&sub, TRUE, old_byte_order, new_byte_order, p, &p);
192 }
193 break;
194
196 /* fds can only be passed on a local machine, so byte order must always match */
197 _dbus_assert_not_reached("attempted to byteswap unix fds which makes no sense");
198 break;
199
200 default:
201 _dbus_assert_not_reached ("invalid typecode in supposedly-validated signature");
202 break;
203 }
204
205 if (walk_reader_to_end)
206 _dbus_type_reader_next (reader);
207 else
208 break;
209 }
210
211 if (new_p)
212 *new_p = p;
213}
214
225void
227 int signature_start,
228 int old_byte_order,
229 int new_byte_order,
230 DBusString *value_str,
231 int value_pos)
232{
233 DBusTypeReader reader;
234
235 _dbus_assert (value_pos >= 0);
236 _dbus_assert (value_pos <= _dbus_string_get_length (value_str));
237
238 if (old_byte_order == new_byte_order)
239 return;
240
242 signature, signature_start);
243
244 byteswap_body_helper (&reader, TRUE,
245 old_byte_order, new_byte_order,
246 _dbus_string_get_udata_len (value_str, value_pos, 0),
247 NULL);
248}
249
252/* 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:215
_DBUS_GNUC_EXTENSION typedef unsigned long dbus_uint64_t
A 64-bit unsigned integer.
dbus_uint32_t dbus_bool_t
A boolean, valid values are TRUE and FALSE.
Definition: dbus-types.h:35
unsigned short dbus_uint16_t
A 16-bit unsigned integer on all platforms.
unsigned int dbus_uint32_t
A 32-bit unsigned integer on all platforms.
The type reader is an iterator for reading values from a block of values.