1 // Copyright 2013 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4
5 #include "mojo/system/message_in_transit.h"
6
7 #include <string.h>
8
9 #include "base/compiler_specific.h"
10 #include "base/logging.h"
11 #include "mojo/system/constants.h"
12 #include "mojo/system/transport_data.h"
13
14 namespace mojo {
15 namespace system {
16
17 STATIC_CONST_MEMBER_DEFINITION const MessageInTransit::Type
18 MessageInTransit::kTypeMessagePipeEndpoint;
19 STATIC_CONST_MEMBER_DEFINITION const MessageInTransit::Type
20 MessageInTransit::kTypeMessagePipe;
21 STATIC_CONST_MEMBER_DEFINITION const MessageInTransit::Type
22 MessageInTransit::kTypeChannel;
23 STATIC_CONST_MEMBER_DEFINITION const MessageInTransit::Type
24 MessageInTransit::kTypeRawChannel;
25 STATIC_CONST_MEMBER_DEFINITION const MessageInTransit::Subtype
26 MessageInTransit::kSubtypeMessagePipeEndpointData;
27 STATIC_CONST_MEMBER_DEFINITION const MessageInTransit::Subtype
28 MessageInTransit::kSubtypeChannelRunMessagePipeEndpoint;
29 STATIC_CONST_MEMBER_DEFINITION const MessageInTransit::Subtype
30 MessageInTransit::kSubtypeChannelRemoveMessagePipeEndpoint;
31 STATIC_CONST_MEMBER_DEFINITION const MessageInTransit::Subtype
32 MessageInTransit::kSubtypeChannelRemoveMessagePipeEndpointAck;
33 STATIC_CONST_MEMBER_DEFINITION const MessageInTransit::Subtype
34 MessageInTransit::kSubtypeRawChannelPosixExtraPlatformHandles;
35 STATIC_CONST_MEMBER_DEFINITION const MessageInTransit::EndpointId
36 MessageInTransit::kInvalidEndpointId;
37 STATIC_CONST_MEMBER_DEFINITION const size_t MessageInTransit::kMessageAlignment;
38
39 struct MessageInTransit::PrivateStructForCompileAsserts {
40 // The size of |Header| must be a multiple of the alignment.
41 COMPILE_ASSERT(sizeof(Header) % kMessageAlignment == 0,
42 sizeof_MessageInTransit_Header_invalid);
43 // Avoid dangerous situations, but making sure that the size of the "header" +
44 // the size of the data fits into a 31-bit number.
45 COMPILE_ASSERT(static_cast<uint64_t>(sizeof(Header)) + kMaxMessageNumBytes <=
46 0x7fffffffULL,
47 kMaxMessageNumBytes_too_big);
48
49 // We assume (to avoid extra rounding code) that the maximum message (data)
50 // size is a multiple of the alignment.
51 COMPILE_ASSERT(kMaxMessageNumBytes % kMessageAlignment == 0,
52 kMessageAlignment_not_a_multiple_of_alignment);
53 };
54
View(size_t message_size,const void * buffer)55 MessageInTransit::View::View(size_t message_size, const void* buffer)
56 : buffer_(buffer) {
57 size_t next_message_size = 0;
58 DCHECK(MessageInTransit::GetNextMessageSize(buffer_, message_size,
59 &next_message_size));
60 DCHECK_EQ(message_size, next_message_size);
61 // This should be equivalent.
62 DCHECK_EQ(message_size, total_size());
63 }
64
IsValid(size_t serialized_platform_handle_size,const char ** error_message) const65 bool MessageInTransit::View::IsValid(size_t serialized_platform_handle_size,
66 const char** error_message) const {
67 // Note: This also implies a check on the |main_buffer_size()|, which is just
68 // |RoundUpMessageAlignment(sizeof(Header) + num_bytes())|.
69 if (num_bytes() > kMaxMessageNumBytes) {
70 *error_message = "Message data payload too large";
71 return false;
72 }
73
74 if (transport_data_buffer_size() > 0) {
75 const char* e =
76 TransportData::ValidateBuffer(serialized_platform_handle_size,
77 transport_data_buffer(),
78 transport_data_buffer_size());
79 if (e) {
80 *error_message = e;
81 return false;
82 }
83 }
84
85 return true;
86 }
87
MessageInTransit(Type type,Subtype subtype,uint32_t num_bytes,const void * bytes)88 MessageInTransit::MessageInTransit(Type type,
89 Subtype subtype,
90 uint32_t num_bytes,
91 const void* bytes)
92 : main_buffer_size_(RoundUpMessageAlignment(sizeof(Header) + num_bytes)),
93 main_buffer_(static_cast<char*>(base::AlignedAlloc(main_buffer_size_,
94 kMessageAlignment))) {
95 DCHECK_LE(num_bytes, kMaxMessageNumBytes);
96
97 // |total_size| is updated below, from the other values.
98 header()->type = type;
99 header()->subtype = subtype;
100 header()->source_id = kInvalidEndpointId;
101 header()->destination_id = kInvalidEndpointId;
102 header()->num_bytes = num_bytes;
103 header()->unused = 0;
104 // Note: If dispatchers are subsequently attached, then |total_size| will have
105 // to be adjusted.
106 UpdateTotalSize();
107
108 if (bytes) {
109 memcpy(MessageInTransit::bytes(), bytes, num_bytes);
110 memset(static_cast<char*>(MessageInTransit::bytes()) + num_bytes, 0,
111 main_buffer_size_ - sizeof(Header) - num_bytes);
112 } else {
113 memset(MessageInTransit::bytes(), 0, main_buffer_size_ - sizeof(Header));
114 }
115 }
116
MessageInTransit(const View & message_view)117 MessageInTransit::MessageInTransit(const View& message_view)
118 : main_buffer_size_(message_view.main_buffer_size()),
119 main_buffer_(static_cast<char*>(base::AlignedAlloc(main_buffer_size_,
120 kMessageAlignment))) {
121 DCHECK_GE(main_buffer_size_, sizeof(Header));
122 DCHECK_EQ(main_buffer_size_ % kMessageAlignment, 0u);
123
124 memcpy(main_buffer_.get(), message_view.main_buffer(), main_buffer_size_);
125 DCHECK_EQ(main_buffer_size_,
126 RoundUpMessageAlignment(sizeof(Header) + num_bytes()));
127 }
128
~MessageInTransit()129 MessageInTransit::~MessageInTransit() {
130 if (dispatchers_) {
131 for (size_t i = 0; i < dispatchers_->size(); i++) {
132 if (!(*dispatchers_)[i])
133 continue;
134
135 DCHECK((*dispatchers_)[i]->HasOneRef());
136 (*dispatchers_)[i]->Close();
137 }
138 }
139 }
140
141 // static
GetNextMessageSize(const void * buffer,size_t buffer_size,size_t * next_message_size)142 bool MessageInTransit::GetNextMessageSize(const void* buffer,
143 size_t buffer_size,
144 size_t* next_message_size) {
145 DCHECK(next_message_size);
146 if (!buffer_size)
147 return false;
148 DCHECK(buffer);
149 DCHECK_EQ(reinterpret_cast<uintptr_t>(buffer) %
150 MessageInTransit::kMessageAlignment, 0u);
151
152 if (buffer_size < sizeof(Header))
153 return false;
154
155 const Header* header = static_cast<const Header*>(buffer);
156 *next_message_size = header->total_size;
157 DCHECK_EQ(*next_message_size % kMessageAlignment, 0u);
158 return true;
159 }
160
SetDispatchers(scoped_ptr<DispatcherVector> dispatchers)161 void MessageInTransit::SetDispatchers(
162 scoped_ptr<DispatcherVector> dispatchers) {
163 DCHECK(dispatchers);
164 DCHECK(!dispatchers_);
165 DCHECK(!transport_data_);
166
167 dispatchers_ = dispatchers.Pass();
168 #ifndef NDEBUG
169 for (size_t i = 0; i < dispatchers_->size(); i++)
170 DCHECK(!(*dispatchers_)[i] || (*dispatchers_)[i]->HasOneRef());
171 #endif
172 }
173
SetTransportData(scoped_ptr<TransportData> transport_data)174 void MessageInTransit::SetTransportData(
175 scoped_ptr<TransportData> transport_data) {
176 DCHECK(transport_data);
177 DCHECK(!transport_data_);
178 DCHECK(!dispatchers_);
179
180 transport_data_ = transport_data.Pass();
181 }
182
SerializeAndCloseDispatchers(Channel * channel)183 void MessageInTransit::SerializeAndCloseDispatchers(Channel* channel) {
184 DCHECK(channel);
185 DCHECK(!transport_data_);
186
187 if (!dispatchers_ || !dispatchers_->size())
188 return;
189
190 transport_data_.reset(new TransportData(dispatchers_.Pass(), channel));
191
192 // Update the sizes in the message header.
193 UpdateTotalSize();
194 }
195
UpdateTotalSize()196 void MessageInTransit::UpdateTotalSize() {
197 DCHECK_EQ(main_buffer_size_ % kMessageAlignment, 0u);
198 header()->total_size = static_cast<uint32_t>(main_buffer_size_);
199 if (transport_data_) {
200 header()->total_size +=
201 static_cast<uint32_t>(transport_data_->buffer_size());
202 }
203 }
204
205 } // namespace system
206 } // namespace mojo
207