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 }
  76
  77 void HidConnectionLinux::PlatformClose() {
  78   Disconnect();
  79   Flush();
  80 }
  81
  82 void HidConnectionLinux::PlatformRead(const ReadCallback& callback) {
  83   PendingHidRead pending_read;
  84   pending_read.callback = callback;
  85   pending_reads_.push(pending_read);
  86   ProcessReadQueue();
  87 }
  88
  89 void HidConnectionLinux::PlatformWrite(scoped_refptr<net::IOBuffer> buffer,
  90                                        size_t size,
  91                                        const WriteCallback& callback) {
  92   // Linux expects the first byte of the buffer to always be a report ID so the
  93   // buffer can be used directly.
  94   const ssize_t bytes_written =
  95       HANDLE_EINTR(write(device_file_.GetPlatformFile(), buffer->data(), size));
  96   if (bytes_written < 0) {
  97     VPLOG(1) << "Write failed";
  98     Disconnect();
  99     callback.Run(false);
 100   } else {
 101     if (static_cast<size_t>(bytes_written) != size) {
 102       LOG(WARNING) << "Incomplete HID write: " << bytes_written
 103                    << " != " << size;
 104     }
 105     callback.Run(true);
 106   }
 107 }
 108
 109 void HidConnectionLinux::PlatformGetFeatureReport(
 110     uint8_t report_id,
 111     const ReadCallback& callback) {
 112   // The first byte of the destination buffer is the report ID being requested
 113   // and is overwritten by the feature report.
 114   DCHECK_GT(device_info().max_feature_report_size, 0u);
 115   scoped_refptr<net::IOBufferWithSize> buffer(
 116       new net::IOBufferWithSize(device_info().max_feature_report_size + 1));
 117   buffer->data()[0] = report_id;
 118
 119   int result = ioctl(device_file_.GetPlatformFile(),
 120                      HIDIOCGFEATURE(buffer->size()),
 121                      buffer->data());
 122   if (result < 0) {
 123     VPLOG(1) << "Failed to get feature report";
 124     callback.Run(false, NULL, 0);
 125   } else if (result == 0) {
 126     VLOG(1) << "Get feature result too short.";
 127     callback.Run(false, NULL, 0);
 128   } else if (report_id == 0) {
 129     // Linux adds a 0 to the beginning of the data received from the device.
 130     scoped_refptr<net::IOBuffer> copied_buffer(new net::IOBuffer(result - 1));
 131     memcpy(copied_buffer->data(), buffer->data() + 1, result - 1);
 132     callback.Run(true, copied_buffer, result - 1);
 133   } else {
 134     callback.Run(true, buffer, result);
 135   }
 136 }
 137
 138 void HidConnectionLinux::PlatformSendFeatureReport(
 139     scoped_refptr<net::IOBuffer> buffer,
 140     size_t size,
 141     const WriteCallback& callback) {
 142   // Linux expects the first byte of the buffer to always be a report ID so the
 143   // buffer can be used directly.
 144   int result = ioctl(
 145       device_file_.GetPlatformFile(), HIDIOCSFEATURE(size), buffer->data());
 146   if (result < 0) {
 147     VPLOG(1) << "Failed to send feature report";
 148     callback.Run(false);
 149   } else {
 150     callback.Run(true);
 151   }
 152 }
 153
 154 void HidConnectionLinux::OnFileCanReadWithoutBlocking(int fd) {
 155   DCHECK(thread_checker().CalledOnValidThread());
 156   DCHECK_EQ(fd, device_file_.GetPlatformFile());
 157
 158   size_t expected_report_size = device_info().max_input_report_size + 1;
 159   scoped_refptr<net::IOBuffer> buffer(new net::IOBuffer(expected_report_size));
 160   char* data = buffer->data();
 161   if (!device_info().has_report_id) {
 162     // Linux will not prefix the buffer with a report ID if they are not used
 163     // by the device.
 164     data[0] = 0;
 165     data++;
 166     expected_report_size--;
 167   }
 168
 169   ssize_t bytes_read = HANDLE_EINTR(
 170       read(device_file_.GetPlatformFile(), data, expected_report_size));
 171   if (bytes_read < 0) {
 172     if (errno == EAGAIN) {
 173       return;
 174     }
 175     VPLOG(1) << "Read failed";
 176     Disconnect();
 177     return;
 178   }
 179   if (!device_info().has_report_id) {
 180     // Include the byte prepended earlier.
 181     bytes_read++;
 182   }
 183
 184   ProcessInputReport(buffer, bytes_read);
 185 }
 186
 187 void HidConnectionLinux::OnFileCanWriteWithoutBlocking(int fd) {
 188 }
 189
 190 void HidConnectionLinux::Disconnect() {
 191   DCHECK(thread_checker().CalledOnValidThread());
 192   device_file_watcher_.StopWatchingFileDescriptor();
 193   device_file_.Close();
 194
 195   Flush();
 196 }
 197
 198 void HidConnectionLinux::Flush() {
 199   while (!pending_reads_.empty()) {
 200     pending_reads_.front().callback.Run(false, NULL, 0);
 201     pending_reads_.pop();
 202   }
 203 }
 204
 205 void HidConnectionLinux::ProcessInputReport(scoped_refptr<net::IOBuffer> buffer,
 206                                             size_t size) {
 207   DCHECK(thread_checker().CalledOnValidThread());
 208   PendingHidReport report;
 209   report.buffer = buffer;
 210   report.size = size;
 211   pending_reports_.push(report);
 212   ProcessReadQueue();
 213 }
 214
 215 void HidConnectionLinux::ProcessReadQueue() {
 216   DCHECK(thread_checker().CalledOnValidThread());
 217   while (pending_reads_.size() && pending_reports_.size()) {
 218     PendingHidRead read = pending_reads_.front();
 219     PendingHidReport report = pending_reports_.front();
 220
 221     pending_reports_.pop();
 222     if (CompleteRead(report.buffer, report.size, read.callback)) {
 223       pending_reads_.pop();
 224     }
 225   }
 226 }
 227
 228 }  // namespace device