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      1 /*
      2  * libjingle
      3  * Copyright 2004 Google Inc.
      4  *
      5  * Redistribution and use in source and binary forms, with or without
      6  * modification, are permitted provided that the following conditions are met:
      7  *
      8  *  1. Redistributions of source code must retain the above copyright notice,
      9  *     this list of conditions and the following disclaimer.
     10  *  2. Redistributions in binary form must reproduce the above copyright notice,
     11  *     this list of conditions and the following disclaimer in the documentation
     12  *     and/or other materials provided with the distribution.
     13  *  3. The name of the author may not be used to endorse or promote products
     14  *     derived from this software without specific prior written permission.
     15  *
     16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
     17  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
     18  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
     19  * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     20  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
     21  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
     22  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
     23  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
     24  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
     25  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     26  */
     27 
     28 #include "talk/media/devices/linuxdevicemanager.h"
     29 
     30 #include <unistd.h>
     31 #include "talk/media/base/mediacommon.h"
     32 #include "talk/media/devices/libudevsymboltable.h"
     33 #include "talk/media/devices/v4llookup.h"
     34 #include "webrtc/sound/platformsoundsystem.h"
     35 #include "webrtc/sound/platformsoundsystemfactory.h"
     36 #include "webrtc/sound/sounddevicelocator.h"
     37 #include "webrtc/sound/soundsysteminterface.h"
     38 #include "webrtc/base/fileutils.h"
     39 #include "webrtc/base/linux.h"
     40 #include "webrtc/base/logging.h"
     41 #include "webrtc/base/pathutils.h"
     42 #include "webrtc/base/physicalsocketserver.h"
     43 #include "webrtc/base/stream.h"
     44 #include "webrtc/base/stringutils.h"
     45 #include "webrtc/base/thread.h"
     46 
     47 namespace cricket {
     48 
     49 DeviceManagerInterface* DeviceManagerFactory::Create() {
     50   return new LinuxDeviceManager();
     51 }
     52 
     53 class LinuxDeviceWatcher
     54     : public DeviceWatcher,
     55       private rtc::Dispatcher {
     56  public:
     57   explicit LinuxDeviceWatcher(DeviceManagerInterface* dm);
     58   virtual ~LinuxDeviceWatcher();
     59   virtual bool Start();
     60   virtual void Stop();
     61 
     62  private:
     63   virtual uint32_t GetRequestedEvents();
     64   virtual void OnPreEvent(uint32_t ff);
     65   virtual void OnEvent(uint32_t ff, int err);
     66   virtual int GetDescriptor();
     67   virtual bool IsDescriptorClosed();
     68 
     69   DeviceManagerInterface* manager_;
     70   LibUDevSymbolTable libudev_;
     71   struct udev* udev_;
     72   struct udev_monitor* udev_monitor_;
     73   bool registered_;
     74 };
     75 
     76 static const char* const kFilteredAudioDevicesName[] = {
     77 #if defined(CHROMEOS)
     78     "surround40:",
     79     "surround41:",
     80     "surround50:",
     81     "surround51:",
     82     "surround71:",
     83     "iec958:",      // S/PDIF
     84 #endif
     85     NULL,
     86 };
     87 static const char* kFilteredVideoDevicesName[] = {
     88     NULL,
     89 };
     90 
     91 LinuxDeviceManager::LinuxDeviceManager()
     92     : sound_system_(new rtc::PlatformSoundSystemFactory()) {
     93   set_watcher(new LinuxDeviceWatcher(this));
     94 }
     95 
     96 LinuxDeviceManager::~LinuxDeviceManager() {
     97 }
     98 
     99 bool LinuxDeviceManager::GetAudioDevices(bool input,
    100                                          std::vector<Device>* devs) {
    101   devs->clear();
    102   if (!sound_system_.get()) {
    103     return false;
    104   }
    105   rtc::SoundSystemInterface::SoundDeviceLocatorList list;
    106   bool success;
    107   if (input) {
    108     success = sound_system_->EnumerateCaptureDevices(&list);
    109   } else {
    110     success = sound_system_->EnumeratePlaybackDevices(&list);
    111   }
    112   if (!success) {
    113     LOG(LS_ERROR) << "Can't enumerate devices";
    114     sound_system_.release();
    115     return false;
    116   }
    117   // We have to start the index at 1 because webrtc VoiceEngine puts the default
    118   // device at index 0, but Enumerate(Capture|Playback)Devices does not include
    119   // a locator for the default device.
    120   int index = 1;
    121   for (rtc::SoundSystemInterface::SoundDeviceLocatorList::iterator i = list.begin();
    122        i != list.end();
    123        ++i, ++index) {
    124     devs->push_back(Device((*i)->name(), index));
    125   }
    126   rtc::SoundSystemInterface::ClearSoundDeviceLocatorList(&list);
    127   sound_system_.release();
    128   return FilterDevices(devs, kFilteredAudioDevicesName);
    129 }
    130 
    131 static const std::string kVideoMetaPathK2_4("/proc/video/dev/");
    132 static const std::string kVideoMetaPathK2_6("/sys/class/video4linux/");
    133 
    134 enum MetaType { M2_4, M2_6, NONE };
    135 
    136 static void ScanDeviceDirectory(const std::string& devdir,
    137                                 std::vector<Device>* devices) {
    138   rtc::scoped_ptr<rtc::DirectoryIterator> directoryIterator(
    139       rtc::Filesystem::IterateDirectory());
    140 
    141   if (directoryIterator->Iterate(rtc::Pathname(devdir))) {
    142     do {
    143       std::string filename = directoryIterator->Name();
    144       std::string device_name = devdir + filename;
    145       if (!directoryIterator->IsDots()) {
    146         if (filename.find("video") == 0 &&
    147             V4LLookup::IsV4L2Device(device_name)) {
    148           devices->push_back(Device(device_name, device_name));
    149         }
    150       }
    151     } while (directoryIterator->Next());
    152   }
    153 }
    154 
    155 static std::string GetVideoDeviceNameK2_6(const std::string& device_meta_path) {
    156   std::string device_name;
    157 
    158   rtc::scoped_ptr<rtc::FileStream> device_meta_stream(
    159       rtc::Filesystem::OpenFile(device_meta_path, "r"));
    160 
    161   if (device_meta_stream) {
    162     if (device_meta_stream->ReadLine(&device_name) != rtc::SR_SUCCESS) {
    163       LOG(LS_ERROR) << "Failed to read V4L2 device meta " << device_meta_path;
    164     }
    165     device_meta_stream->Close();
    166   }
    167 
    168   return device_name;
    169 }
    170 
    171 static std::string Trim(const std::string& s, const std::string& drop = " \t") {
    172   std::string::size_type first = s.find_first_not_of(drop);
    173   std::string::size_type last  = s.find_last_not_of(drop);
    174 
    175   if (first == std::string::npos || last == std::string::npos)
    176     return std::string("");
    177 
    178   return s.substr(first, last - first + 1);
    179 }
    180 
    181 static std::string GetVideoDeviceNameK2_4(const std::string& device_meta_path) {
    182   rtc::ConfigParser::MapVector all_values;
    183 
    184   rtc::ConfigParser config_parser;
    185   rtc::FileStream* file_stream =
    186       rtc::Filesystem::OpenFile(device_meta_path, "r");
    187 
    188   if (file_stream == NULL) return "";
    189 
    190   config_parser.Attach(file_stream);
    191   config_parser.Parse(&all_values);
    192 
    193   for (rtc::ConfigParser::MapVector::iterator i = all_values.begin();
    194       i != all_values.end(); ++i) {
    195     rtc::ConfigParser::SimpleMap::iterator device_name_i =
    196         i->find("name");
    197 
    198     if (device_name_i != i->end()) {
    199       return device_name_i->second;
    200     }
    201   }
    202 
    203   return "";
    204 }
    205 
    206 static std::string GetVideoDeviceName(MetaType meta,
    207     const std::string& device_file_name) {
    208   std::string device_meta_path;
    209   std::string device_name;
    210   std::string meta_file_path;
    211 
    212   if (meta == M2_6) {
    213     meta_file_path = kVideoMetaPathK2_6 + device_file_name + "/name";
    214 
    215     LOG(LS_INFO) << "Trying " + meta_file_path;
    216     device_name = GetVideoDeviceNameK2_6(meta_file_path);
    217 
    218     if (device_name.empty()) {
    219       meta_file_path = kVideoMetaPathK2_6 + device_file_name + "/model";
    220 
    221       LOG(LS_INFO) << "Trying " << meta_file_path;
    222       device_name = GetVideoDeviceNameK2_6(meta_file_path);
    223     }
    224   } else {
    225     meta_file_path = kVideoMetaPathK2_4 + device_file_name;
    226     LOG(LS_INFO) << "Trying " << meta_file_path;
    227     device_name = GetVideoDeviceNameK2_4(meta_file_path);
    228   }
    229 
    230   if (device_name.empty()) {
    231     device_name = "/dev/" + device_file_name;
    232     LOG(LS_ERROR)
    233       << "Device name not found, defaulting to device path " << device_name;
    234   }
    235 
    236   LOG(LS_INFO) << "Name for " << device_file_name << " is " << device_name;
    237 
    238   return Trim(device_name);
    239 }
    240 
    241 static void ScanV4L2Devices(std::vector<Device>* devices) {
    242   LOG(LS_INFO) << ("Enumerating V4L2 devices");
    243 
    244   MetaType meta;
    245   std::string metadata_dir;
    246 
    247   rtc::scoped_ptr<rtc::DirectoryIterator> directoryIterator(
    248       rtc::Filesystem::IterateDirectory());
    249 
    250   // Try and guess kernel version
    251   if (directoryIterator->Iterate(kVideoMetaPathK2_6)) {
    252     meta = M2_6;
    253     metadata_dir = kVideoMetaPathK2_6;
    254   } else if (directoryIterator->Iterate(kVideoMetaPathK2_4)) {
    255     meta = M2_4;
    256     metadata_dir = kVideoMetaPathK2_4;
    257   } else {
    258     meta = NONE;
    259   }
    260 
    261   if (meta != NONE) {
    262     LOG(LS_INFO) << "V4L2 device metadata found at " << metadata_dir;
    263 
    264     do {
    265       std::string filename = directoryIterator->Name();
    266 
    267       if (filename.find("video") == 0) {
    268         std::string device_path = "/dev/" + filename;
    269 
    270         if (V4LLookup::IsV4L2Device(device_path)) {
    271           devices->push_back(
    272               Device(GetVideoDeviceName(meta, filename), device_path));
    273         }
    274       }
    275     } while (directoryIterator->Next());
    276   } else {
    277     LOG(LS_ERROR) << "Unable to detect v4l2 metadata directory";
    278   }
    279 
    280   if (devices->size() == 0) {
    281     LOG(LS_INFO) << "Plan B. Scanning all video devices in /dev directory";
    282     ScanDeviceDirectory("/dev/", devices);
    283   }
    284 
    285   LOG(LS_INFO) << "Total V4L2 devices found : " << devices->size();
    286 }
    287 
    288 bool LinuxDeviceManager::GetVideoCaptureDevices(std::vector<Device>* devices) {
    289   devices->clear();
    290   ScanV4L2Devices(devices);
    291   return FilterDevices(devices, kFilteredVideoDevicesName);
    292 }
    293 
    294 LinuxDeviceWatcher::LinuxDeviceWatcher(DeviceManagerInterface* dm)
    295     : DeviceWatcher(dm),
    296       manager_(dm),
    297       udev_(NULL),
    298       udev_monitor_(NULL),
    299       registered_(false) {
    300 }
    301 
    302 LinuxDeviceWatcher::~LinuxDeviceWatcher() {
    303 }
    304 
    305 static rtc::PhysicalSocketServer* CurrentSocketServer() {
    306   rtc::SocketServer* ss =
    307       rtc::ThreadManager::Instance()->WrapCurrentThread()->socketserver();
    308   return reinterpret_cast<rtc::PhysicalSocketServer*>(ss);
    309 }
    310 
    311 bool LinuxDeviceWatcher::Start() {
    312   // We deliberately return true in the failure paths here because libudev is
    313   // not a critical component of a Linux system so it may not be present/usable,
    314   // and we don't want to halt LinuxDeviceManager initialization in such a case.
    315   if (!libudev_.Load() || IsWrongLibUDevAbiVersion(libudev_.GetDllHandle())) {
    316     LOG(LS_WARNING)
    317         << "libudev not present/usable; LinuxDeviceWatcher disabled";
    318     return true;
    319   }
    320   udev_ = libudev_.udev_new()();
    321   if (!udev_) {
    322     LOG_ERR(LS_ERROR) << "udev_new()";
    323     return true;
    324   }
    325   // The second argument here is the event source. It can be either "kernel" or
    326   // "udev", but "udev" is the only correct choice. Apps listen on udev and the
    327   // udev daemon in turn listens on the kernel.
    328   udev_monitor_ = libudev_.udev_monitor_new_from_netlink()(udev_, "udev");
    329   if (!udev_monitor_) {
    330     LOG_ERR(LS_ERROR) << "udev_monitor_new_from_netlink()";
    331     return true;
    332   }
    333   // We only listen for changes in the video devices. Audio devices are more or
    334   // less unimportant because receiving device change notifications really only
    335   // matters for broadcasting updated send/recv capabilities based on whether
    336   // there is at least one device available, and almost all computers have at
    337   // least one audio device. Also, PulseAudio device notifications don't come
    338   // from the udev daemon, they come from the PulseAudio daemon, so we'd only
    339   // want to listen for audio device changes from udev if using ALSA. For
    340   // simplicity, we don't bother with any audio stuff at all.
    341   if (libudev_.udev_monitor_filter_add_match_subsystem_devtype()(
    342           udev_monitor_, "video4linux", NULL) < 0) {
    343     LOG_ERR(LS_ERROR) << "udev_monitor_filter_add_match_subsystem_devtype()";
    344     return true;
    345   }
    346   if (libudev_.udev_monitor_enable_receiving()(udev_monitor_) < 0) {
    347     LOG_ERR(LS_ERROR) << "udev_monitor_enable_receiving()";
    348     return true;
    349   }
    350   CurrentSocketServer()->Add(this);
    351   registered_ = true;
    352   return true;
    353 }
    354 
    355 void LinuxDeviceWatcher::Stop() {
    356   if (registered_) {
    357     CurrentSocketServer()->Remove(this);
    358     registered_ = false;
    359   }
    360   if (udev_monitor_) {
    361     libudev_.udev_monitor_unref()(udev_monitor_);
    362     udev_monitor_ = NULL;
    363   }
    364   if (udev_) {
    365     libudev_.udev_unref()(udev_);
    366     udev_ = NULL;
    367   }
    368   libudev_.Unload();
    369 }
    370 
    371 uint32_t LinuxDeviceWatcher::GetRequestedEvents() {
    372   return rtc::DE_READ;
    373 }
    374 
    375 void LinuxDeviceWatcher::OnPreEvent(uint32_t ff) {
    376   // Nothing to do.
    377 }
    378 
    379 void LinuxDeviceWatcher::OnEvent(uint32_t ff, int err) {
    380   udev_device* device = libudev_.udev_monitor_receive_device()(udev_monitor_);
    381   if (!device) {
    382     // Probably the socket connection to the udev daemon was terminated (perhaps
    383     // the daemon crashed or is being restarted?).
    384     LOG_ERR(LS_WARNING) << "udev_monitor_receive_device()";
    385     // Stop listening to avoid potential livelock (an fd with EOF in it is
    386     // always considered readable).
    387     CurrentSocketServer()->Remove(this);
    388     registered_ = false;
    389     return;
    390   }
    391   // Else we read the device successfully.
    392 
    393   // Since we already have our own filesystem-based device enumeration code, we
    394   // simply re-enumerate rather than inspecting the device event.
    395   libudev_.udev_device_unref()(device);
    396   manager_->SignalDevicesChange();
    397 }
    398 
    399 int LinuxDeviceWatcher::GetDescriptor() {
    400   return libudev_.udev_monitor_get_fd()(udev_monitor_);
    401 }
    402 
    403 bool LinuxDeviceWatcher::IsDescriptorClosed() {
    404   // If it is closed then we will just get an error in
    405   // udev_monitor_receive_device and unregister, so we don't need to check for
    406   // it separately.
    407   return false;
    408 }
    409 
    410 };  // namespace cricket
    411