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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 
Create()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 
LinuxDeviceManager()91 LinuxDeviceManager::LinuxDeviceManager()
92     : sound_system_(new rtc::PlatformSoundSystemFactory()) {
93   set_watcher(new LinuxDeviceWatcher(this));
94 }
95 
~LinuxDeviceManager()96 LinuxDeviceManager::~LinuxDeviceManager() {
97 }
98 
GetAudioDevices(bool input,std::vector<Device> * devs)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 
ScanDeviceDirectory(const std::string & devdir,std::vector<Device> * devices)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 
GetVideoDeviceNameK2_6(const std::string & device_meta_path)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 
Trim(const std::string & s,const std::string & drop=" \\t")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 
GetVideoDeviceNameK2_4(const std::string & device_meta_path)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 
GetVideoDeviceName(MetaType meta,const std::string & device_file_name)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 
ScanV4L2Devices(std::vector<Device> * devices)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 
GetVideoCaptureDevices(std::vector<Device> * devices)288 bool LinuxDeviceManager::GetVideoCaptureDevices(std::vector<Device>* devices) {
289   devices->clear();
290   ScanV4L2Devices(devices);
291   return FilterDevices(devices, kFilteredVideoDevicesName);
292 }
293 
LinuxDeviceWatcher(DeviceManagerInterface * dm)294 LinuxDeviceWatcher::LinuxDeviceWatcher(DeviceManagerInterface* dm)
295     : DeviceWatcher(dm),
296       manager_(dm),
297       udev_(NULL),
298       udev_monitor_(NULL),
299       registered_(false) {
300 }
301 
~LinuxDeviceWatcher()302 LinuxDeviceWatcher::~LinuxDeviceWatcher() {
303 }
304 
CurrentSocketServer()305 static rtc::PhysicalSocketServer* CurrentSocketServer() {
306   rtc::SocketServer* ss =
307       rtc::ThreadManager::Instance()->WrapCurrentThread()->socketserver();
308   return reinterpret_cast<rtc::PhysicalSocketServer*>(ss);
309 }
310 
Start()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 
Stop()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 
GetRequestedEvents()371 uint32_t LinuxDeviceWatcher::GetRequestedEvents() {
372   return rtc::DE_READ;
373 }
374 
OnPreEvent(uint32_t ff)375 void LinuxDeviceWatcher::OnPreEvent(uint32_t ff) {
376   // Nothing to do.
377 }
378 
OnEvent(uint32_t ff,int err)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 
GetDescriptor()399 int LinuxDeviceWatcher::GetDescriptor() {
400   return libudev_.udev_monitor_get_fd()(udev_monitor_);
401 }
402 
IsDescriptorClosed()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