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- // Copyright (c) 2014 The Chromium Authors. All rights reserved.
- // Use of this source code is governed by a BSD-style license that can be
- // found in the LICENSE file.
- #include "services/device/hid/hid_connection_linux.h"
- #include <errno.h>
- #include <linux/hidraw.h>
- #include <sys/ioctl.h>
- #include <memory>
- #include <string>
- #include <utility>
- #include "base/bind.h"
- #include "base/files/file_descriptor_watcher_posix.h"
- #include "base/memory/ref_counted_memory.h"
- #include "base/posix/eintr_wrapper.h"
- #include "base/threading/scoped_blocking_call.h"
- #include "base/threading/sequenced_task_runner_handle.h"
- #include "components/device_event_log/device_event_log.h"
- #include "services/device/hid/hid_service.h"
- // These are already defined in newer versions of linux/hidraw.h.
- #ifndef HIDIOCSFEATURE
- #define HIDIOCSFEATURE(len) _IOC(_IOC_WRITE | _IOC_READ, 'H', 0x06, len)
- #endif
- #ifndef HIDIOCGFEATURE
- #define HIDIOCGFEATURE(len) _IOC(_IOC_WRITE | _IOC_READ, 'H', 0x07, len)
- #endif
- namespace device {
- class HidConnectionLinux::BlockingTaskRunnerHelper {
- public:
- BlockingTaskRunnerHelper(base::ScopedFD fd,
- scoped_refptr<HidDeviceInfo> device_info,
- base::WeakPtr<HidConnectionLinux> connection)
- : fd_(std::move(fd)),
- connection_(connection),
- origin_task_runner_(base::SequencedTaskRunnerHandle::Get()) {
- DETACH_FROM_SEQUENCE(sequence_checker_);
- // Report buffers must always have room for the report ID.
- report_buffer_size_ = device_info->max_input_report_size() + 1;
- has_report_id_ = device_info->has_report_id();
- }
- BlockingTaskRunnerHelper(const BlockingTaskRunnerHelper&) = delete;
- BlockingTaskRunnerHelper& operator=(const BlockingTaskRunnerHelper&) = delete;
- ~BlockingTaskRunnerHelper() {
- DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
- }
- // Starts the FileDescriptorWatcher that reads input events from the device.
- // Must be called on a thread that has a base::MessageLoopForIO.
- void Start() {
- DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
- file_watcher_ = base::FileDescriptorWatcher::WatchReadable(
- fd_.get(), base::BindRepeating(
- &BlockingTaskRunnerHelper::OnFileCanReadWithoutBlocking,
- base::Unretained(this)));
- }
- void Write(scoped_refptr<base::RefCountedBytes> buffer,
- WriteCallback callback) {
- DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
- base::ScopedBlockingCall scoped_blocking_call(
- FROM_HERE, base::BlockingType::MAY_BLOCK);
- ssize_t result =
- HANDLE_EINTR(write(fd_.get(), buffer->front(), buffer->size()));
- if (result < 0) {
- HID_PLOG(EVENT) << "Write failed";
- origin_task_runner_->PostTask(FROM_HERE,
- base::BindOnce(std::move(callback), false));
- } else {
- if (static_cast<size_t>(result) != buffer->size()) {
- HID_LOG(EVENT) << "Incomplete HID write: " << result
- << " != " << buffer->size();
- }
- origin_task_runner_->PostTask(FROM_HERE,
- base::BindOnce(std::move(callback), true));
- }
- }
- void GetFeatureReport(uint8_t report_id,
- scoped_refptr<base::RefCountedBytes> buffer,
- ReadCallback callback) {
- DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
- base::ScopedBlockingCall scoped_blocking_call(
- FROM_HERE, base::BlockingType::MAY_BLOCK);
- int result = HANDLE_EINTR(
- ioctl(fd_.get(), HIDIOCGFEATURE(buffer->size()), buffer->front()));
- if (result < 0) {
- HID_PLOG(EVENT) << "Failed to get feature report";
- origin_task_runner_->PostTask(
- FROM_HERE, base::BindOnce(std::move(callback), false, nullptr, 0));
- } else if (result == 0) {
- HID_LOG(EVENT) << "Get feature result too short.";
- origin_task_runner_->PostTask(
- FROM_HERE, base::BindOnce(std::move(callback), false, nullptr, 0));
- } else if (report_id == 0) {
- // Linux adds a 0 to the beginning of the data received from the device.
- auto copied_buffer =
- base::MakeRefCounted<base::RefCountedBytes>(result - 1);
- memcpy(copied_buffer->front(), buffer->front() + 1, result - 1);
- origin_task_runner_->PostTask(
- FROM_HERE,
- base::BindOnce(std::move(callback), true, copied_buffer, result - 1));
- } else {
- origin_task_runner_->PostTask(
- FROM_HERE, base::BindOnce(std::move(callback), true, buffer, result));
- }
- }
- void SendFeatureReport(scoped_refptr<base::RefCountedBytes> buffer,
- WriteCallback callback) {
- DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
- base::ScopedBlockingCall scoped_blocking_call(
- FROM_HERE, base::BlockingType::MAY_BLOCK);
- int result = HANDLE_EINTR(
- ioctl(fd_.get(), HIDIOCSFEATURE(buffer->size()), buffer->front()));
- if (result < 0) {
- HID_PLOG(EVENT) << "Failed to send feature report";
- origin_task_runner_->PostTask(FROM_HERE,
- base::BindOnce(std::move(callback), false));
- } else {
- origin_task_runner_->PostTask(FROM_HERE,
- base::BindOnce(std::move(callback), true));
- }
- }
- private:
- void OnFileCanReadWithoutBlocking() {
- DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
- auto buffer =
- base::MakeRefCounted<base::RefCountedBytes>(report_buffer_size_);
- uint8_t* data = buffer->front();
- size_t length = report_buffer_size_;
- if (!has_report_id_) {
- // Linux will not prefix the buffer with a report ID if report IDs are not
- // used by the device. Prefix the buffer with 0.
- *data++ = 0;
- length--;
- }
- ssize_t bytes_read = HANDLE_EINTR(read(fd_.get(), data, length));
- if (bytes_read < 0) {
- if (errno != EAGAIN) {
- HID_PLOG(EVENT) << "Read failed";
- // This assumes that the error is unrecoverable and disables reading
- // from the device until it has been re-opened.
- // TODO(reillyg): Investigate starting and stopping the file descriptor
- // watcher in response to pending read requests so that per-request
- // errors can be returned to the client.
- file_watcher_.reset();
- }
- return;
- }
- if (!has_report_id_) {
- // Behave as if the byte prefixed above as the the report ID was read.
- bytes_read++;
- }
- origin_task_runner_->PostTask(
- FROM_HERE, base::BindOnce(&HidConnectionLinux::ProcessInputReport,
- connection_, buffer, bytes_read));
- }
- SEQUENCE_CHECKER(sequence_checker_);
- base::ScopedFD fd_;
- size_t report_buffer_size_;
- bool has_report_id_;
- base::WeakPtr<HidConnectionLinux> connection_;
- const scoped_refptr<base::SequencedTaskRunner> origin_task_runner_;
- std::unique_ptr<base::FileDescriptorWatcher::Controller> file_watcher_;
- };
- HidConnectionLinux::HidConnectionLinux(
- scoped_refptr<HidDeviceInfo> device_info,
- base::ScopedFD fd,
- scoped_refptr<base::SequencedTaskRunner> blocking_task_runner,
- bool allow_protected_reports,
- bool allow_fido_reports)
- : HidConnection(device_info, allow_protected_reports, allow_fido_reports),
- helper_(nullptr, base::OnTaskRunnerDeleter(blocking_task_runner)),
- blocking_task_runner_(std::move(blocking_task_runner)) {
- helper_.reset(new BlockingTaskRunnerHelper(std::move(fd), device_info,
- weak_factory_.GetWeakPtr()));
- blocking_task_runner_->PostTask(
- FROM_HERE, base::BindOnce(&BlockingTaskRunnerHelper::Start,
- base::Unretained(helper_.get())));
- }
- HidConnectionLinux::~HidConnectionLinux() {}
- void HidConnectionLinux::PlatformClose() {
- // By closing the device on the blocking task runner 1) the requirement that
- // base::ScopedFD is destroyed on a thread where I/O is allowed is satisfied
- // and 2) any tasks posted to this task runner that refer to this file will
- // complete before it is closed.
- helper_.reset();
- }
- void HidConnectionLinux::PlatformWrite(
- scoped_refptr<base::RefCountedBytes> buffer,
- WriteCallback callback) {
- // Linux expects the first byte of the buffer to always be a report ID so the
- // buffer can be used directly.
- blocking_task_runner_->PostTask(
- FROM_HERE, base::BindOnce(&BlockingTaskRunnerHelper::Write,
- base::Unretained(helper_.get()), buffer,
- std::move(callback)));
- }
- void HidConnectionLinux::PlatformGetFeatureReport(uint8_t report_id,
- ReadCallback callback) {
- // The first byte of the destination buffer is the report ID being requested
- // and is overwritten by the feature report.
- DCHECK_GT(device_info()->max_feature_report_size(), 0u);
- auto buffer = base::MakeRefCounted<base::RefCountedBytes>(
- device_info()->max_feature_report_size() + 1);
- buffer->data()[0] = report_id;
- blocking_task_runner_->PostTask(
- FROM_HERE, base::BindOnce(&BlockingTaskRunnerHelper::GetFeatureReport,
- base::Unretained(helper_.get()), report_id,
- buffer, std::move(callback)));
- }
- void HidConnectionLinux::PlatformSendFeatureReport(
- scoped_refptr<base::RefCountedBytes> buffer,
- WriteCallback callback) {
- // Linux expects the first byte of the buffer to always be a report ID so the
- // buffer can be used directly.
- blocking_task_runner_->PostTask(
- FROM_HERE, base::BindOnce(&BlockingTaskRunnerHelper::SendFeatureReport,
- base::Unretained(helper_.get()), buffer,
- std::move(callback)));
- }
- } // namespace device
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