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/threading/thread_restrictions.h"
   9 #include "base/win/scoped_handle.h"
  10
  11 namespace base {
  12
  13 using win::ScopedHandle;
  14
  15 namespace {
  16 // IMPORTANT: do not change how this name is generated because it will break
  17 // in sandboxed scenarios as we might have by-name policies that allow pipe
  18 // creation. Also keep the secure random number generation.
  19 const wchar_t kPipeNameFormat[] = L"\\\\.\\pipe\\chrome.sync.%u.%u.%lu";
  20 const size_t kPipePathMax =  arraysize(kPipeNameFormat) + (3 * 10) + 1;
  21
  22 // To avoid users sending negative message lengths to Send/Receive
  23 // we clamp message lengths, which are size_t, to no more than INT_MAX.
  24 const size_t kMaxMessageLength = static_cast<size_t>(INT_MAX);
  25
  26 const int kOutBufferSize = 4096;
  27 const int kInBufferSize = 4096;
  28 const int kDefaultTimeoutMilliSeconds = 1000;
  29
  30 bool CreatePairImpl(HANDLE* socket_a, HANDLE* socket_b, bool overlapped) {
  31   DCHECK_NE(socket_a, socket_b);
  32   DCHECK_EQ(*socket_a, SyncSocket::kInvalidHandle);
  33   DCHECK_EQ(*socket_b, SyncSocket::kInvalidHandle);
  34
  35   wchar_t name[kPipePathMax];
  36   ScopedHandle handle_a;
  37   DWORD flags = PIPE_ACCESS_DUPLEX | FILE_FLAG_FIRST_PIPE_INSTANCE;
  38   if (overlapped)
  39     flags |= FILE_FLAG_OVERLAPPED;
  40
  41   do {
  42     unsigned int rnd_name;
  43     if (rand_s(&rnd_name) != 0)
  44       return false;
  45
  46     swprintf(name, kPipePathMax,
  47              kPipeNameFormat,
  48              GetCurrentProcessId(),
  49              GetCurrentThreadId(),
  50              rnd_name);
  51
  52     handle_a.Set(CreateNamedPipeW(
  53         name,
  54         flags,
  55         PIPE_TYPE_BYTE | PIPE_READMODE_BYTE,
  56         1,
  57         kOutBufferSize,
  58         kInBufferSize,
  59         kDefaultTimeoutMilliSeconds,
  60         NULL));
  61   } while (!handle_a.IsValid() &&
  62            (GetLastError() == ERROR_PIPE_BUSY));
  63
  64   if (!handle_a.IsValid()) {
  65     NOTREACHED();
  66     return false;
  67   }
  68
  69   // The SECURITY_ANONYMOUS flag means that the server side (handle_a) cannot
  70   // impersonate the client (handle_b). This allows us not to care which side
  71   // ends up in which side of a privilege boundary.
  72   flags = SECURITY_SQOS_PRESENT | SECURITY_ANONYMOUS;
  73   if (overlapped)
  74     flags |= FILE_FLAG_OVERLAPPED;
  75
  76   ScopedHandle handle_b(CreateFileW(name,
  77                                     GENERIC_READ | GENERIC_WRITE,
  78                                     0,          // no sharing.
  79                                     NULL,       // default security attributes.
  80                                     OPEN_EXISTING,  // opens existing pipe.
  81                                     flags,
  82                                     NULL));     // no template file.
  83   if (!handle_b.IsValid()) {
  84     DPLOG(ERROR) << "CreateFileW failed";
  85     return false;
  86   }
  87
  88   if (!ConnectNamedPipe(handle_a.Get(), NULL)) {
  89     DWORD error = GetLastError();
  90     if (error != ERROR_PIPE_CONNECTED) {
  91       DPLOG(ERROR) << "ConnectNamedPipe failed";
  92       return false;
  93     }
  94   }
  95
  96   *socket_a = handle_a.Take();
  97   *socket_b = handle_b.Take();
  98
  99   return true;
 100 }
 101
 102 // Inline helper to avoid having the cast everywhere.
 103 DWORD GetNextChunkSize(size_t current_pos, size_t max_size) {
 104   // The following statement is for 64 bit portability.
 105   return static_cast<DWORD>(((max_size - current_pos) <= UINT_MAX) ?
 106       (max_size - current_pos) : UINT_MAX);
 107 }
 108
 109 // Template function that supports calling ReadFile or WriteFile in an
 110 // overlapped fashion and waits for IO completion.  The function also waits
 111 // on an event that can be used to cancel the operation.  If the operation
 112 // is cancelled, the function returns and closes the relevant socket object.
 113 template <typename BufferType, typename Function>
 114 size_t CancelableFileOperation(Function operation,
 115                                HANDLE file,
 116                                BufferType* buffer,
 117                                size_t length,
 118                                WaitableEvent* io_event,
 119                                WaitableEvent* cancel_event,
 120                                CancelableSyncSocket* socket,
 121                                DWORD timeout_in_ms) {
 122   ThreadRestrictions::AssertIOAllowed();
 123   // The buffer must be byte size or the length check won't make much sense.
 124   COMPILE_ASSERT(sizeof(buffer[0]) == sizeof(char), incorrect_buffer_type);
 125   DCHECK_GT(length, 0u);
 126   DCHECK_LE(length, kMaxMessageLength);
 127   DCHECK_NE(file, SyncSocket::kInvalidHandle);
 128
 129   // Track the finish time so we can calculate the timeout as data is read.
 130   TimeTicks current_time, finish_time;
 131   if (timeout_in_ms != INFINITE) {
 132     current_time = TimeTicks::Now();
 133     finish_time =
 134         current_time + base::TimeDelta::FromMilliseconds(timeout_in_ms);
 135   }
 136
 137   size_t count = 0;
 138   do {
 139     // The OVERLAPPED structure will be modified by ReadFile or WriteFile.
 140     OVERLAPPED ol = { 0 };
 141     ol.hEvent = io_event->handle();
 142
 143     const DWORD chunk = GetNextChunkSize(count, length);
 144     // This is either the ReadFile or WriteFile call depending on whether
 145     // we're receiving or sending data.
 146     DWORD len = 0;
 147     const BOOL operation_ok = operation(
 148         file, static_cast<BufferType*>(buffer) + count, chunk, &len, &ol);
 149     if (!operation_ok) {
 150       if (::GetLastError() == ERROR_IO_PENDING) {
 151         HANDLE events[] = { io_event->handle(), cancel_event->handle() };
 152         const int wait_result = WaitForMultipleObjects(
 153             ARRAYSIZE_UNSAFE(events), events, FALSE,
 154             timeout_in_ms == INFINITE
 155                 ? timeout_in_ms
 156                 : (finish_time - current_time).InMilliseconds());
 157         if (wait_result != WAIT_OBJECT_0 + 0) {
 158           // CancelIo() doesn't synchronously cancel outstanding IO, only marks
 159           // outstanding IO for cancellation. We must call GetOverlappedResult()
 160           // below to ensure in flight writes complete before returning.
 161           CancelIo(file);
 162         }
 163
 164         // We set the |bWait| parameter to TRUE for GetOverlappedResult() to
 165         // ensure writes are complete before returning.
 166         if (!GetOverlappedResult(file, &ol, &len, TRUE))
 167           len = 0;
 168
 169         if (wait_result == WAIT_OBJECT_0 + 1) {
 170           DVLOG(1) << "Shutdown was signaled. Closing socket.";
 171           socket->Close();
 172           return count;
 173         }
 174
 175         // Timeouts will be handled by the while() condition below since
 176         // GetOverlappedResult() may complete successfully after CancelIo().
 177         DCHECK(wait_result == WAIT_OBJECT_0 + 0 || wait_result == WAIT_TIMEOUT);
 178       } else {
 179         break;
 180       }
 181     }
 182
 183     count += len;
 184
 185     // Quit the operation if we can't write/read anymore.
 186     if (len != chunk)
 187       break;
 188
 189     // Since TimeTicks::Now() is expensive, only bother updating the time if we
 190     // have more work to do.
 191     if (timeout_in_ms != INFINITE && count < length)
 192       current_time = base::TimeTicks::Now();
 193   } while (count < length &&
 194            (timeout_in_ms == INFINITE || current_time < finish_time));
 195
 196   return count;
 197 }
 198
 199 }  // namespace
 200
 201 #if defined(COMPONENT_BUILD)
 202 const SyncSocket::Handle SyncSocket::kInvalidHandle = INVALID_HANDLE_VALUE;
 203 #endif
 204
 205 SyncSocket::SyncSocket() : handle_(kInvalidHandle) {}
 206
 207 SyncSocket::~SyncSocket() {
 208   Close();
 209 }
 210
 211 // static
 212 bool SyncSocket::CreatePair(SyncSocket* socket_a, SyncSocket* socket_b) {
 213   return CreatePairImpl(&socket_a->handle_, &socket_b->handle_, false);
 214 }
 215
 216 // static
 217 SyncSocket::Handle SyncSocket::UnwrapHandle(
 218     const TransitDescriptor& descriptor) {
 219   return descriptor;
 220 }
 221
 222 bool SyncSocket::PrepareTransitDescriptor(ProcessHandle peer_process_handle,
 223                                           TransitDescriptor* descriptor) {
 224   DCHECK(descriptor);
 225   if (!::DuplicateHandle(GetCurrentProcess(), handle(), peer_process_handle,
 226                          descriptor, 0, FALSE, DUPLICATE_SAME_ACCESS)) {
 227     DPLOG(ERROR) << "Cannot duplicate socket handle for peer process.";
 228     return false;
 229   }
 230   return true;
 231 }
 232
 233 bool SyncSocket::Close() {
 234   if (handle_ == kInvalidHandle)
 235     return true;
 236
 237   const BOOL result = CloseHandle(handle_);
 238   handle_ = kInvalidHandle;
 239   return result == TRUE;
 240 }
 241
 242 size_t SyncSocket::Send(const void* buffer, size_t length) {
 243   ThreadRestrictions::AssertIOAllowed();
 244   DCHECK_GT(length, 0u);
 245   DCHECK_LE(length, kMaxMessageLength);
 246   DCHECK_NE(handle_, kInvalidHandle);
 247   size_t count = 0;
 248   while (count < length) {
 249     DWORD len;
 250     DWORD chunk = GetNextChunkSize(count, length);
 251     if (WriteFile(handle_, static_cast<const char*>(buffer) + count,
 252                   chunk, &len, NULL) == FALSE) {
 253       return count;
 254     }
 255     count += len;
 256   }
 257   return count;
 258 }
 259
 260 size_t SyncSocket::ReceiveWithTimeout(void* buffer,
 261                                       size_t length,
 262                                       TimeDelta timeout) {
 263   NOTIMPLEMENTED();
 264   return 0;
 265 }
 266
 267 size_t SyncSocket::Receive(void* buffer, size_t length) {
 268   ThreadRestrictions::AssertIOAllowed();
 269   DCHECK_GT(length, 0u);
 270   DCHECK_LE(length, kMaxMessageLength);
 271   DCHECK_NE(handle_, kInvalidHandle);
 272   size_t count = 0;
 273   while (count < length) {
 274     DWORD len;
 275     DWORD chunk = GetNextChunkSize(count, length);
 276     if (ReadFile(handle_, static_cast<char*>(buffer) + count,
 277                  chunk, &len, NULL) == FALSE) {
 278       return count;
 279     }
 280     count += len;
 281   }
 282   return count;
 283 }
 284
 285 size_t SyncSocket::Peek() {
 286   DWORD available = 0;
 287   PeekNamedPipe(handle_, NULL, 0, NULL, &available, NULL);
 288   return available;
 289 }
 290
 291 CancelableSyncSocket::CancelableSyncSocket()
 292     : shutdown_event_(true, false), file_operation_(true, false) {
 293 }
 294
 295 CancelableSyncSocket::CancelableSyncSocket(Handle handle)
 296     : SyncSocket(handle), shutdown_event_(true, false),
 297       file_operation_(true, false) {
 298 }
 299
 300 bool CancelableSyncSocket::Shutdown() {
 301   // This doesn't shut down the pipe immediately, but subsequent Receive or Send
 302   // methods will fail straight away.
 303   shutdown_event_.Signal();
 304   return true;
 305 }
 306
 307 bool CancelableSyncSocket::Close() {
 308   const bool result = SyncSocket::Close();
 309   shutdown_event_.Reset();
 310   return result;
 311 }
 312
 313 size_t CancelableSyncSocket::Send(const void* buffer, size_t length) {
 314   static const DWORD kWaitTimeOutInMs = 500;
 315   return CancelableFileOperation(
 316       &WriteFile, handle_, reinterpret_cast<const char*>(buffer),
 317       length, &file_operation_, &shutdown_event_, this, kWaitTimeOutInMs);
 318 }
 319
 320 size_t CancelableSyncSocket::Receive(void* buffer, size_t length) {
 321   return CancelableFileOperation(
 322       &ReadFile, handle_, reinterpret_cast<char*>(buffer), length,
 323       &file_operation_, &shutdown_event_, this, INFINITE);
 324 }
 325
 326 size_t CancelableSyncSocket::ReceiveWithTimeout(void* buffer,
 327                                                 size_t length,
 328                                                 TimeDelta timeout) {
 329   return CancelableFileOperation(
 330       &ReadFile, handle_, reinterpret_cast<char*>(buffer), length,
 331       &file_operation_, &shutdown_event_, this, timeout.InMilliseconds());
 332 }
 333
 334 // static
 335 bool CancelableSyncSocket::CreatePair(CancelableSyncSocket* socket_a,
 336                                       CancelableSyncSocket* socket_b) {
 337   return CreatePairImpl(&socket_a->handle_, &socket_b->handle_, true);
 338 }
 339
 340 }  // namespace base