1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
|
// Copyright 2013 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifdef UNSAFE_BUFFERS_BUILD
// TODO(crbug.com/40285824): Remove this and convert code to safer constructs.
#pragma allow_unsafe_buffers
#endif
#include "remoting/host/native_messaging/native_messaging_reader.h"
#include <cstdint>
#include <memory>
#include <string>
#include <utility>
#include "base/files/file.h"
#include "base/functional/bind.h"
#include "base/json/json_reader.h"
#include "base/location.h"
#include "base/logging.h"
#include "base/message_loop/message_pump_type.h"
#include "base/task/sequenced_task_runner.h"
#include "base/task/single_thread_task_runner.h"
#include "base/threading/thread.h"
#include "base/values.h"
#include "build/build_config.h"
#if BUILDFLAG(IS_WIN)
#include <windows.h>
#include "base/threading/platform_thread.h"
#include "base/win/scoped_handle.h"
#endif // BUILDFLAG(IS_WIN)
namespace {
// uint32_t is specified in the protocol as the type for the message header.
typedef uint32_t MessageLengthType;
const int kMessageHeaderSize = sizeof(MessageLengthType);
// Limit the size of received messages, to avoid excessive memory-allocation in
// this process, and potential overflow issues when casting to a signed 32-bit
// int.
const MessageLengthType kMaximumMessageSize = 1024 * 1024;
} // namespace
namespace remoting {
class NativeMessagingReader::Core {
public:
Core(base::File file,
scoped_refptr<base::SingleThreadTaskRunner> caller_task_runner,
scoped_refptr<base::SequencedTaskRunner> read_task_runner,
base::WeakPtr<NativeMessagingReader> reader_);
Core(const Core&) = delete;
Core& operator=(const Core&) = delete;
~Core();
// Reads a message from the Native Messaging client and passes it to
// |message_callback_| on the originating thread. Called on the reader thread.
void ReadMessage();
private:
// Notify the reader's EOF callback when an error occurs or EOF is reached.
void NotifyEof();
base::File read_stream_;
base::WeakPtr<NativeMessagingReader> reader_;
// Used to post the caller-supplied reader callbacks on the caller thread.
scoped_refptr<base::SingleThreadTaskRunner> caller_task_runner_;
// Used to DCHECK that the reader code executes on the correct thread.
scoped_refptr<base::SequencedTaskRunner> read_task_runner_;
};
NativeMessagingReader::Core::Core(
base::File file,
scoped_refptr<base::SingleThreadTaskRunner> caller_task_runner,
scoped_refptr<base::SequencedTaskRunner> read_task_runner,
base::WeakPtr<NativeMessagingReader> reader)
: read_stream_(std::move(file)),
reader_(reader),
caller_task_runner_(caller_task_runner),
read_task_runner_(read_task_runner) {}
NativeMessagingReader::Core::~Core() = default;
void NativeMessagingReader::Core::ReadMessage() {
DCHECK(read_task_runner_->RunsTasksInCurrentSequence());
// Keep reading messages until the stream is closed or an error occurs.
while (true) {
MessageLengthType message_length;
int read_result = read_stream_.ReadAtCurrentPos(
reinterpret_cast<char*>(&message_length), kMessageHeaderSize);
if (read_result != kMessageHeaderSize) {
// 0 means EOF which is normal and should not be logged as an error.
if (read_result != 0) {
LOG(ERROR) << "Failed to read message header, read returned "
<< read_result;
}
NotifyEof();
return;
}
if (message_length > kMaximumMessageSize) {
LOG(ERROR) << "Message size too large: " << message_length;
NotifyEof();
return;
}
std::string message_json(message_length, '\0');
read_result =
read_stream_.ReadAtCurrentPos(std::data(message_json), message_length);
if (read_result != static_cast<int>(message_length)) {
LOG(ERROR) << "Failed to read message body, read returned "
<< read_result;
NotifyEof();
return;
}
std::optional<base::Value> message = base::JSONReader::Read(message_json);
if (!message) {
LOG(ERROR) << "Failed to parse JSON message: " << message_json;
NotifyEof();
return;
}
// Notify callback of new message.
caller_task_runner_->PostTask(
FROM_HERE, base::BindOnce(&NativeMessagingReader::InvokeMessageCallback,
reader_, std::move(*message)));
}
}
void NativeMessagingReader::Core::NotifyEof() {
DCHECK(read_task_runner_->RunsTasksInCurrentSequence());
caller_task_runner_->PostTask(
FROM_HERE,
base::BindOnce(&NativeMessagingReader::InvokeEofCallback, reader_));
}
NativeMessagingReader::NativeMessagingReader(base::File file)
: reader_thread_("Reader") {
reader_thread_.StartWithOptions(
base::Thread::Options(base::MessagePumpType::IO, /*size=*/0));
read_task_runner_ = reader_thread_.task_runner();
core_ = std::make_unique<Core>(
std::move(file), base::SingleThreadTaskRunner::GetCurrentDefault(),
read_task_runner_, weak_factory_.GetWeakPtr());
}
NativeMessagingReader::~NativeMessagingReader() {
read_task_runner_->DeleteSoon(FROM_HERE, core_.release());
#if BUILDFLAG(IS_WIN)
// The ReadMessage() method uses a blocking read (on all platforms) which
// cause a deadlock if the owning thread attempts to destroy this object
// while there is a read operation pending.
// On POSIX platforms, closing the write end of the pipe causes the Chrome
// process to close the read end so that this class can be cleaned up.
// On Windows, closing the write end of the pipe does nothing as the parent
// process is cmd.exe which doesn't care. Thus, the read end of the pipe
// remains open, the read operation is blocked, and we hang in the d'tor.
// Canceling the pending I/O here prevents the hang on Windows and isn't
// needed for POSIX since it works correctly.
base::PlatformThreadId thread_id = reader_thread_.GetThreadId();
base::win::ScopedHandle thread_handle(
OpenThread(THREAD_TERMINATE, /*bInheritHandle=*/false, thread_id.raw()));
if (!CancelSynchronousIo(thread_handle.Get())) {
// ERROR_NOT_FOUND means there were no pending IO requests so don't treat
// that result as an error.
if (GetLastError() != ERROR_NOT_FOUND) {
PLOG(ERROR) << "CancelSynchronousIo() failed";
}
}
#endif // BUILDFLAG(IS_WIN)
}
void NativeMessagingReader::Start(const MessageCallback& message_callback,
base::OnceClosure eof_callback) {
message_callback_ = message_callback;
eof_callback_ = std::move(eof_callback);
// base::Unretained is safe since |core_| is only deleted via the
// DeleteSoon task which is posted from this class's dtor.
read_task_runner_->PostTask(
FROM_HERE, base::BindOnce(&NativeMessagingReader::Core::ReadMessage,
base::Unretained(core_.get())));
}
void NativeMessagingReader::InvokeMessageCallback(base::Value message) {
message_callback_.Run(std::move(message));
}
void NativeMessagingReader::InvokeEofCallback() {
std::move(eof_callback_).Run();
}
} // namespace remoting
|
