ipc/glue/Transport_win.h

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #ifndef mozilla_ipc_Transport_win_h
   8 #define mozilla_ipc_Transport_win_h 1
   9
  10 #include <string>
  11
  12 #include "base/process.h"
  13 #include "ipc/IPCMessageUtils.h"
  14 #include "nsWindowsHelpers.h"
  15
  16 namespace mozilla {
  17 namespace ipc {
  18
  19 struct TransportDescriptor {
  20   std::wstring mPipeName;
  21   HANDLE mServerPipeHandle;
  22   base::ProcessId mDestinationProcessId;
  23 };
  24
  25 HANDLE
  26 TransferHandleToProcess(HANDLE source, base::ProcessId pid);
  27
  28 }  // namespace ipc
  29 }  // namespace mozilla
  30
  31 namespace IPC {
  32
  33 template <>
  34 struct ParamTraits<mozilla::ipc::TransportDescriptor> {
  35   typedef mozilla::ipc::TransportDescriptor paramType;
  36   static void Write(Message* aMsg, const paramType& aParam) {
  37     HANDLE pipe = mozilla::ipc::TransferHandleToProcess(
  38         aParam.mServerPipeHandle, aParam.mDestinationProcessId);
  39     DWORD duplicateFromProcessId = 0;
  40     if (!pipe) {
  41       if (XRE_IsParentProcess()) {
  42         // If we are the parent and failed to transfer then there is no hope,
  43         // just close the handle.
  44         ::CloseHandle(aParam.mServerPipeHandle);
  45       } else {
  46         // We are probably sending to parent so it should be able to duplicate.
  47         pipe = aParam.mServerPipeHandle;
  48         duplicateFromProcessId = ::GetCurrentProcessId();
  49       }
  50     }
  51
  52     WriteParam(aMsg, aParam.mPipeName);
  53     WriteParam(aMsg, pipe);
  54     WriteParam(aMsg, duplicateFromProcessId);
  55     WriteParam(aMsg, aParam.mDestinationProcessId);
  56   }
  57   static bool Read(const Message* aMsg, PickleIterator* aIter,
  58                    paramType* aResult) {
  59     DWORD duplicateFromProcessId;
  60     bool r = (ReadParam(aMsg, aIter, &aResult->mPipeName) &&
  61               ReadParam(aMsg, aIter, &aResult->mServerPipeHandle) &&
  62               ReadParam(aMsg, aIter, &duplicateFromProcessId) &&
  63               ReadParam(aMsg, aIter, &aResult->mDestinationProcessId));
  64     if (!r) {
  65       return r;
  66     }
  67
  68     MOZ_RELEASE_ASSERT(
  69         aResult->mServerPipeHandle,
  70         "Main process failed to duplicate pipe handle to child.");
  71
  72     // If this is a not the "server" side descriptor, we have finished.
  73     if (aResult->mServerPipeHandle == INVALID_HANDLE_VALUE) {
  74       return true;
  75     }
  76
  77     MOZ_RELEASE_ASSERT(aResult->mDestinationProcessId ==
  78                        base::GetCurrentProcId());
  79
  80     // If the pipe has already been duplicated to us, we have finished.
  81     if (!duplicateFromProcessId) {
  82       return true;
  83     }
  84
  85     // Otherwise duplicate the handle to us.
  86     nsAutoHandle sourceProcess(
  87         ::OpenProcess(PROCESS_DUP_HANDLE, FALSE, duplicateFromProcessId));
  88     if (!sourceProcess) {
  89       return false;
  90     }
  91
  92     HANDLE ourHandle;
  93     BOOL duped = ::DuplicateHandle(
  94         sourceProcess, aResult->mServerPipeHandle, ::GetCurrentProcess(),
  95         &ourHandle, 0, FALSE, DUPLICATE_CLOSE_SOURCE | DUPLICATE_SAME_ACCESS);
  96     if (!duped) {
  97       aResult->mServerPipeHandle = INVALID_HANDLE_VALUE;
  98       return false;
  99     }
 100
 101     aResult->mServerPipeHandle = ourHandle;
 102     return true;
 103   }
 104 };
 105
 106 }  // namespace IPC
 107
 108 #endif  // mozilla_ipc_Transport_win_h