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 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 65 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 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 } 116 117 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 } 128 129 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 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 } 160 161 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 } 173 174 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 } 182 183 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 } 195 196 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
