src/mojo/embedder/platform_channel_pair_win.cc

   1 // Copyright 2014 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/embedder/platform_channel_pair.h"
   6
   7 #include <windows.h>
   8
   9 #include <string>
  10
  11 #include "base/command_line.h"
  12 #include "base/logging.h"
  13 #include "base/rand_util.h"
  14 #include "base/strings/string_number_conversions.h"
  15 #include "base/strings/stringprintf.h"
  16 #include "base/win/windows_version.h"
  17 #include "mojo/embedder/platform_handle.h"
  18
  19 namespace mojo {
  20 namespace embedder {
  21
  22 namespace {
  23
  24 std::wstring GeneratePipeName() {
  25   return base::StringPrintf(L"\\\\.\\pipe\\mojo.%u.%u.%I64u",
  26                             GetCurrentProcessId(),
  27                             GetCurrentThreadId(),
  28                             base::RandUint64());
  29 }
  30
  31 }  // namespace
  32
  33 PlatformChannelPair::PlatformChannelPair() {
  34   std::wstring pipe_name = GeneratePipeName();
  35
  36   const DWORD kOpenMode =
  37       PIPE_ACCESS_DUPLEX | FILE_FLAG_OVERLAPPED | FILE_FLAG_FIRST_PIPE_INSTANCE;
  38   const DWORD kPipeMode = PIPE_TYPE_BYTE | PIPE_READMODE_BYTE;
  39   server_handle_.reset(PlatformHandle(
  40       CreateNamedPipeW(pipe_name.c_str(),
  41                        kOpenMode,
  42                        kPipeMode,
  43                        1,           // Max instances.
  44                        4096,        // Out buffer size.
  45                        4096,        // In buffer size.
  46                        5000,        // Timeout in milliseconds.
  47                        nullptr)));  // Default security descriptor.
  48   PCHECK(server_handle_.is_valid());
  49
  50   const DWORD kDesiredAccess = GENERIC_READ | GENERIC_WRITE;
  51   // The SECURITY_ANONYMOUS flag means that the server side cannot impersonate
  52   // the client.
  53   const DWORD kFlags =
  54       SECURITY_SQOS_PRESENT | SECURITY_ANONYMOUS | FILE_FLAG_OVERLAPPED;
  55   // Allow the handle to be inherited by child processes.
  56   SECURITY_ATTRIBUTES security_attributes = {sizeof(SECURITY_ATTRIBUTES),
  57                                              nullptr, TRUE};
  58   client_handle_.reset(
  59       PlatformHandle(CreateFileW(pipe_name.c_str(),
  60                                  kDesiredAccess,
  61                                  0,  // No sharing.
  62                                  &security_attributes,
  63                                  OPEN_EXISTING,
  64                                  kFlags,
  65                                  nullptr)));  // No template file.
  66   PCHECK(client_handle_.is_valid());
  67
  68   // Since a client has connected, ConnectNamedPipe() should return zero and
  69   // GetLastError() should return ERROR_PIPE_CONNECTED.
  70   CHECK(!ConnectNamedPipe(server_handle_.get().handle, nullptr));
  71   PCHECK(GetLastError() == ERROR_PIPE_CONNECTED);
  72 }
  73
  74 // static
  75 ScopedPlatformHandle PlatformChannelPair::PassClientHandleFromParentProcess(
  76     const base::CommandLine& command_line) {
  77   std::string client_handle_string =
  78       command_line.GetSwitchValueASCII(kMojoPlatformChannelHandleSwitch);
  79
  80   int client_handle_value = 0;
  81   if (client_handle_string.empty() ||
  82       !base::StringToInt(client_handle_string, &client_handle_value)) {
  83     LOG(ERROR) << "Missing or invalid --" << kMojoPlatformChannelHandleSwitch;
  84     return ScopedPlatformHandle();
  85   }
  86
  87   return ScopedPlatformHandle(
  88       PlatformHandle(LongToHandle(client_handle_value)));
  89 }
  90
  91 void PlatformChannelPair::PrepareToPassClientHandleToChildProcess(
  92     base::CommandLine* command_line,
  93     base::HandlesToInheritVector* handle_passing_info) const {
  94   DCHECK(command_line);
  95   DCHECK(handle_passing_info);
  96   DCHECK(client_handle_.is_valid());
  97
  98   CHECK_GE(base::win::GetVersion(), base::win::VERSION_VISTA);
  99
 100   handle_passing_info->push_back(client_handle_.get().handle);
 101
 102   // Log a warning if the command line already has the switch, but "clobber" it
 103   // anyway, since it's reasonably likely that all the switches were just copied
 104   // from the parent.
 105   LOG_IF(WARNING, command_line->HasSwitch(kMojoPlatformChannelHandleSwitch))
 106       << "Child command line already has switch --"
 107       << kMojoPlatformChannelHandleSwitch << "="
 108       << command_line->GetSwitchValueASCII(kMojoPlatformChannelHandleSwitch);
 109   // (Any existing switch won't actually be removed from the command line, but
 110   // the last one appended takes precedence.)
 111   command_line->AppendSwitchASCII(
 112       kMojoPlatformChannelHandleSwitch,
 113       base::IntToString(HandleToLong(client_handle_.get().handle)));
 114 }
 115
 116 }  // namespace embedder
 117 }  // namespace mojo