base/sync_socket_win.cc

   1 // Copyright (c) 2012 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 "base/sync_socket.h"
   6
   7 #include "base/logging.h"
   8 #include "base/win/scoped_handle.h"
   9
  10 namespace base {
  11
  12 using win::ScopedHandle;
  13
  14 namespace {
  15 // IMPORTANT: do not change how this name is generated because it will break
  16 // in sandboxed scenarios as we might have by-name policies that allow pipe
  17 // creation. Also keep the secure random number generation.
  18 const wchar_t kPipeNameFormat[] = L"\\\\.\\pipe\\chrome.sync.%u.%u.%lu";
  19 const size_t kPipePathMax =  arraysize(kPipeNameFormat) + (3 * 10) + 1;
  20
  21 // To avoid users sending negative message lengths to Send/Receive
  22 // we clamp message lengths, which are size_t, to no more than INT_MAX.
  23 const size_t kMaxMessageLength = static_cast<size_t>(INT_MAX);
  24
  25 const int kOutBufferSize = 4096;
  26 const int kInBufferSize = 4096;
  27 const int kDefaultTimeoutMilliSeconds = 1000;
  28
  29 bool CreatePairImpl(HANDLE* socket_a, HANDLE* socket_b, bool overlapped) {
  30   DCHECK(socket_a != socket_b);
  31   DCHECK(*socket_a == SyncSocket::kInvalidHandle);
  32   DCHECK(*socket_b == SyncSocket::kInvalidHandle);
  33
  34   wchar_t name[kPipePathMax];
  35   ScopedHandle handle_a;
  36   DWORD flags = PIPE_ACCESS_DUPLEX | FILE_FLAG_FIRST_PIPE_INSTANCE;
  37   if (overlapped)
  38     flags |= FILE_FLAG_OVERLAPPED;
  39
  40   do {
  41     unsigned int rnd_name;
  42     if (rand_s(&rnd_name) != 0)
  43       return false;
  44
  45     swprintf(name, kPipePathMax,
  46              kPipeNameFormat,
  47              GetCurrentProcessId(),
  48              GetCurrentThreadId(),
  49              rnd_name);
  50
  51     handle_a.Set(CreateNamedPipeW(
  52         name,
  53         flags,
  54         PIPE_TYPE_BYTE | PIPE_READMODE_BYTE,
  55         1,
  56         kOutBufferSize,
  57         kInBufferSize,
  58         kDefaultTimeoutMilliSeconds,
  59         NULL));
  60   } while (!handle_a.IsValid() &&
  61            (GetLastError() == ERROR_PIPE_BUSY));
  62
  63   if (!handle_a.IsValid()) {
  64     NOTREACHED();
  65     return false;
  66   }
  67
  68   // The SECURITY_ANONYMOUS flag means that the server side (handle_a) cannot
  69   // impersonate the client (handle_b). This allows us not to care which side
  70   // ends up in which side of a privilege boundary.
  71   flags = SECURITY_SQOS_PRESENT | SECURITY_ANONYMOUS;
  72   if (overlapped)
  73     flags |= FILE_FLAG_OVERLAPPED;
  74
  75   ScopedHandle handle_b(CreateFileW(name,
  76                                     GENERIC_READ | GENERIC_WRITE,
  77                                     0,          // no sharing.
  78                                     NULL,       // default security attributes.
  79                                     OPEN_EXISTING,  // opens existing pipe.
  80                                     flags,
  81                                     NULL));     // no template file.
  82   if (!handle_b.IsValid()) {
  83     DPLOG(ERROR) << "CreateFileW failed";
  84     return false;
  85   }
  86
  87   if (!ConnectNamedPipe(handle_a, NULL)) {
  88     DWORD error = GetLastError();
  89     if (error != ERROR_PIPE_CONNECTED) {
  90       DPLOG(ERROR) << "ConnectNamedPipe failed";
  91       return false;
  92     }
  93   }
  94
  95   *socket_a = handle_a.Take();
  96   *socket_b = handle_b.Take();
  97
  98   return true;
  99 }
 100
 101 // Inline helper to avoid having the cast everywhere.
 102 DWORD GetNextChunkSize(size_t current_pos, size_t max_size) {
 103   // The following statement is for 64 bit portability.
 104   return static_cast<DWORD>(((max_size - current_pos) <= UINT_MAX) ?
 105       (max_size - current_pos) : UINT_MAX);
 106 }
 107
 108 // Template function that supports calling ReadFile or WriteFile in an
 109 // overlapped fashion and waits for IO completion.  The function also waits
 110 // on an event that can be used to cancel the operation.  If the operation
 111 // is cancelled, the function returns and closes the relevant socket object.
 112 template <typename BufferType, typename Function>
 113 size_t CancelableFileOperation(Function operation, HANDLE file,
 114                                BufferType* buffer, size_t length,
 115                                base::WaitableEvent* io_event,
 116                                base::WaitableEvent* cancel_event,
 117                                CancelableSyncSocket* socket,
 118                                DWORD timeout_in_ms) {
 119   // The buffer must be byte size or the length check won't make much sense.
 120   COMPILE_ASSERT(sizeof(buffer[0]) == sizeof(char), incorrect_buffer_type);
 121   DCHECK_LE(length, kMaxMessageLength);
 122
 123   OVERLAPPED ol = {0};
 124   ol.hEvent = io_event->handle();
 125   size_t count = 0;
 126   while (count < length) {
 127     DWORD chunk = GetNextChunkSize(count, length);
 128     // This is either the ReadFile or WriteFile call depending on whether
 129     // we're receiving or sending data.
 130     DWORD len = 0;
 131     BOOL ok = operation(file, static_cast<BufferType*>(buffer) + count, chunk,
 132                         &len, &ol);
 133     if (!ok) {
 134       if (::GetLastError() == ERROR_IO_PENDING) {
 135         HANDLE events[] = { io_event->handle(), cancel_event->handle() };
 136         int wait_result = WaitForMultipleObjects(
 137             arraysize(events), events, FALSE, timeout_in_ms);
 138         if (wait_result == (WAIT_OBJECT_0 + 0)) {
 139           GetOverlappedResult(file, &ol, &len, TRUE);
 140         } else if (wait_result == (WAIT_OBJECT_0 + 1)) {
 141           VLOG(1) << "Shutdown was signaled. Closing socket.";
 142           CancelIo(file);
 143           socket->Close();
 144           count = 0;
 145           break;
 146         } else {
 147           // Timeout happened.
 148           DCHECK_EQ(WAIT_TIMEOUT, wait_result);
 149           if (!CancelIo(file)){
 150             DLOG(WARNING) << "CancelIo() failed";
 151           }
 152           break;
 153         }
 154       } else {
 155         break;
 156       }
 157     }
 158
 159     count += len;
 160
 161     // Quit the operation if we can't write/read anymore.
 162     if (len != chunk)
 163       break;
 164   }
 165
 166   return (count > 0) ? count : 0;
 167 }
 168
 169 }  // namespace
 170
 171 const SyncSocket::Handle SyncSocket::kInvalidHandle = INVALID_HANDLE_VALUE;
 172
 173 SyncSocket::SyncSocket() : handle_(kInvalidHandle) {}
 174
 175 SyncSocket::~SyncSocket() {
 176   Close();
 177 }
 178
 179 // static
 180 bool SyncSocket::CreatePair(SyncSocket* socket_a, SyncSocket* socket_b) {
 181   return CreatePairImpl(&socket_a->handle_, &socket_b->handle_, false);
 182 }
 183
 184 bool SyncSocket::Close() {
 185   if (handle_ == kInvalidHandle)
 186     return false;
 187
 188   BOOL retval = CloseHandle(handle_);
 189   handle_ = kInvalidHandle;
 190   return retval ? true : false;
 191 }
 192
 193 size_t SyncSocket::Send(const void* buffer, size_t length) {
 194   DCHECK_LE(length, kMaxMessageLength);
 195   size_t count = 0;
 196   while (count < length) {
 197     DWORD len;
 198     DWORD chunk = GetNextChunkSize(count, length);
 199     if (WriteFile(handle_, static_cast<const char*>(buffer) + count,
 200                   chunk, &len, NULL) == FALSE) {
 201       return (0 < count) ? count : 0;
 202     }
 203     count += len;
 204   }
 205   return count;
 206 }
 207
 208 size_t SyncSocket::Receive(void* buffer, size_t length) {
 209   DCHECK_LE(length, kMaxMessageLength);
 210   size_t count = 0;
 211   while (count < length) {
 212     DWORD len;
 213     DWORD chunk = GetNextChunkSize(count, length);
 214     if (ReadFile(handle_, static_cast<char*>(buffer) + count,
 215                  chunk, &len, NULL) == FALSE) {
 216       return (0 < count) ? count : 0;
 217     }
 218     count += len;
 219   }
 220   return count;
 221 }
 222
 223 size_t SyncSocket::Peek() {
 224   DWORD available = 0;
 225   PeekNamedPipe(handle_, NULL, 0, NULL, &available, NULL);
 226   return available;
 227 }
 228
 229 CancelableSyncSocket::CancelableSyncSocket()
 230     : shutdown_event_(true, false), file_operation_(true, false) {
 231 }
 232
 233 CancelableSyncSocket::CancelableSyncSocket(Handle handle)
 234     : SyncSocket(handle), shutdown_event_(true, false),
 235       file_operation_(true, false) {
 236 }
 237
 238 bool CancelableSyncSocket::Shutdown() {
 239   // This doesn't shut down the pipe immediately, but subsequent Receive or Send
 240   // methods will fail straight away.
 241   shutdown_event_.Signal();
 242   return true;
 243 }
 244
 245 bool CancelableSyncSocket::Close() {
 246   bool ret = SyncSocket::Close();
 247   shutdown_event_.Reset();
 248   return ret;
 249 }
 250
 251 size_t CancelableSyncSocket::Send(const void* buffer, size_t length) {
 252   static const DWORD kWaitTimeOutInMs = 500;
 253   return CancelableFileOperation(
 254       &WriteFile, handle_, reinterpret_cast<const char*>(buffer),
 255       length, &file_operation_, &shutdown_event_, this, kWaitTimeOutInMs);
 256 }
 257
 258 size_t CancelableSyncSocket::Receive(void* buffer, size_t length) {
 259   return CancelableFileOperation(&ReadFile, handle_,
 260       reinterpret_cast<char*>(buffer), length, &file_operation_,
 261       &shutdown_event_, this, INFINITE);
 262 }
 263
 264 // static
 265 bool CancelableSyncSocket::CreatePair(CancelableSyncSocket* socket_a,
 266                                       CancelableSyncSocket* socket_b) {
 267   return CreatePairImpl(&socket_a->handle_, &socket_b->handle_, true);
 268 }
 269
 270
 271 }  // namespace base