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
GeneratePipeName()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
PlatformChannelPair()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
PassClientHandleFromParentProcess(const base::CommandLine & command_line)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
PrepareToPassClientHandleToChildProcess(base::CommandLine * command_line,base::HandlesToInheritVector * handle_passing_info) const91 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
118