device/hid/hid_connection_linux.cc

   1 // Copyright (c) 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 "device/hid/hid_connection_linux.h"
   6
   7 #include <errno.h>
   8 #include <fcntl.h>
   9 #include <libudev.h>
  10 #include <linux/hidraw.h>
  11 #include <sys/ioctl.h>
  12
  13 #include <string>
  14
  15 #include "base/files/file_path.h"
  16 #include "base/message_loop/message_loop.h"
  17 #include "base/posix/eintr_wrapper.h"
  18 #include "base/threading/thread_restrictions.h"
  19 #include "base/tuple.h"
  20 #include "device/hid/hid_service.h"
  21
  22 // These are already defined in newer versions of linux/hidraw.h.
  23 #ifndef HIDIOCSFEATURE
  24 #define HIDIOCSFEATURE(len) _IOC(_IOC_WRITE | _IOC_READ, 'H', 0x06, len)
  25 #endif
  26 #ifndef HIDIOCGFEATURE
  27 #define HIDIOCGFEATURE(len) _IOC(_IOC_WRITE | _IOC_READ, 'H', 0x07, len)
  28 #endif
  29
  30 namespace device {
  31
  32 HidConnectionLinux::HidConnectionLinux(HidDeviceInfo device_info,
  33                                        std::string dev_node)
  34     : HidConnection(device_info) {
  35   int flags = base::File::FLAG_OPEN |
  36               base::File::FLAG_READ |
  37               base::File::FLAG_WRITE;
  38
  39   base::File device_file(base::FilePath(dev_node), flags);
  40   if (!device_file.IsValid()) {
  41     base::File::Error file_error = device_file.error_details();
  42
  43     if (file_error == base::File::FILE_ERROR_ACCESS_DENIED) {
  44       VLOG(1) << "Access denied opening device read-write, trying read-only.";
  45
  46       flags = base::File::FLAG_OPEN | base::File::FLAG_READ;
  47
  48       device_file = base::File(base::FilePath(dev_node), flags);
  49     }
  50   }
  51   if (!device_file.IsValid()) {
  52     LOG(ERROR) << "Failed to open '" << dev_node << "': "
  53         << base::File::ErrorToString(device_file.error_details());
  54     return;
  55   }
  56
  57   if (fcntl(device_file.GetPlatformFile(), F_SETFL,
  58             fcntl(device_file.GetPlatformFile(), F_GETFL) | O_NONBLOCK)) {
  59     PLOG(ERROR) << "Failed to set non-blocking flag to device file";
  60     return;
  61   }
  62   device_file_ = device_file.Pass();
  63
  64   if (!base::MessageLoopForIO::current()->WatchFileDescriptor(
  65       device_file_.GetPlatformFile(),
  66       true,
  67       base::MessageLoopForIO::WATCH_READ_WRITE,
  68       &device_file_watcher_,
  69       this)) {
  70     LOG(ERROR) << "Failed to start watching device file.";
  71   }
  72 }
  73
  74 HidConnectionLinux::~HidConnectionLinux() {
  75   Disconnect();
  76   Flush();
  77 }
  78
  79 void HidConnectionLinux::PlatformRead(const ReadCallback& callback) {
  80   PendingHidRead pending_read;
  81   pending_read.callback = callback;
  82   pending_reads_.push(pending_read);
  83   ProcessReadQueue();
  84 }
  85
  86 void HidConnectionLinux::PlatformWrite(scoped_refptr<net::IOBuffer> buffer,
  87                                        size_t size,
  88                                        const WriteCallback& callback) {
  89   // Linux expects the first byte of the buffer to always be a report ID so the
  90   // buffer can be used directly.
  91   const ssize_t bytes_written =
  92       HANDLE_EINTR(write(device_file_.GetPlatformFile(), buffer->data(), size));
  93   if (bytes_written < 0) {
  94     VPLOG(1) << "Write failed";
  95     Disconnect();
  96     callback.Run(false);
  97   } else {
  98     if (static_cast<size_t>(bytes_written) != size) {
  99       LOG(WARNING) << "Incomplete HID write: " << bytes_written
 100                    << " != " << size;
 101     }
 102     callback.Run(true);
 103   }
 104 }
 105
 106 void HidConnectionLinux::PlatformGetFeatureReport(
 107     uint8_t report_id,
 108     const ReadCallback& callback) {
 109   // The first byte of the destination buffer is the report ID being requested
 110   // and is overwritten by the feature report.
 111   DCHECK_GT(device_info().max_feature_report_size, 0);
 112   scoped_refptr<net::IOBufferWithSize> buffer(
 113       new net::IOBufferWithSize(device_info().max_feature_report_size));
 114   buffer->data()[0] = report_id;
 115
 116   int result = ioctl(device_file_.GetPlatformFile(),
 117                      HIDIOCGFEATURE(buffer->size()),
 118                      buffer->data());
 119   if (result < 0) {
 120     VPLOG(1) << "Failed to get feature report";
 121     callback.Run(false, NULL, 0);
 122   } else {
 123     callback.Run(true, buffer, result);
 124   }
 125 }
 126
 127 void HidConnectionLinux::PlatformSendFeatureReport(
 128     scoped_refptr<net::IOBuffer> buffer,
 129     size_t size,
 130     const WriteCallback& callback) {
 131   // Linux expects the first byte of the buffer to always be a report ID so the
 132   // buffer can be used directly.
 133   int result = ioctl(
 134       device_file_.GetPlatformFile(), HIDIOCSFEATURE(size), buffer->data());
 135   if (result < 0) {
 136     VPLOG(1) << "Failed to send feature report";
 137     callback.Run(false);
 138   } else {
 139     callback.Run(true);
 140   }
 141 }
 142
 143 void HidConnectionLinux::OnFileCanReadWithoutBlocking(int fd) {
 144   DCHECK(thread_checker().CalledOnValidThread());
 145   DCHECK_EQ(fd, device_file_.GetPlatformFile());
 146
 147   size_t expected_report_size = device_info().max_input_report_size + 1;
 148   scoped_refptr<net::IOBuffer> buffer(new net::IOBuffer(expected_report_size));
 149   char* data = buffer->data();
 150   if (!device_info().has_report_id) {
 151     // Linux will not prefix the buffer with a report ID if they are not used
 152     // by the device.
 153     data[0] = 0;
 154     data++;
 155     expected_report_size--;
 156   }
 157
 158   ssize_t bytes_read = HANDLE_EINTR(
 159       read(device_file_.GetPlatformFile(), data, expected_report_size));
 160   if (bytes_read < 0) {
 161     if (errno == EAGAIN) {
 162       return;
 163     }
 164     VPLOG(1) << "Read failed";
 165     Disconnect();
 166     return;
 167   }
 168   if (!device_info().has_report_id) {
 169     // Include the byte prepended earlier.
 170     bytes_read++;
 171   }
 172
 173   ProcessInputReport(buffer, bytes_read);
 174 }
 175
 176 void HidConnectionLinux::OnFileCanWriteWithoutBlocking(int fd) {
 177 }
 178
 179 void HidConnectionLinux::Disconnect() {
 180   DCHECK(thread_checker().CalledOnValidThread());
 181   device_file_watcher_.StopWatchingFileDescriptor();
 182   device_file_.Close();
 183
 184   Flush();
 185 }
 186
 187 void HidConnectionLinux::Flush() {
 188   while (!pending_reads_.empty()) {
 189     pending_reads_.front().callback.Run(false, NULL, 0);
 190     pending_reads_.pop();
 191   }
 192 }
 193
 194 void HidConnectionLinux::ProcessInputReport(scoped_refptr<net::IOBuffer> buffer,
 195                                             size_t size) {
 196   DCHECK(thread_checker().CalledOnValidThread());
 197   PendingHidReport report;
 198   report.buffer = buffer;
 199   report.size = size;
 200   pending_reports_.push(report);
 201   ProcessReadQueue();
 202 }
 203
 204 void HidConnectionLinux::ProcessReadQueue() {
 205   DCHECK(thread_checker().CalledOnValidThread());
 206   while (pending_reads_.size() && pending_reports_.size()) {
 207     PendingHidRead read = pending_reads_.front();
 208     PendingHidReport report = pending_reports_.front();
 209
 210     pending_reports_.pop();
 211     if (CompleteRead(report.buffer, report.size, read.callback)) {
 212       pending_reads_.pop();
 213     }
 214   }
 215 }
 216
 217 }  // namespace device