git.sesse.net Git - nageru/blob - alsa_pool.cpp

   1 #include "alsa_pool.h"
   2
   3 #include <alsa/control.h>
   4 #include <alsa/error.h>
   5 #include <alsa/pcm.h>
   6 #include <assert.h>
   7 #include <limits.h>
   8 #include <stdio.h>
   9 #include <sys/eventfd.h>
  10 #include <sys/inotify.h>
  11 #include <unistd.h>
  12 #include <algorithm>
  13 #include <memory>
  14
  15 #include "alsa_input.h"
  16 #include "audio_mixer.h"
  17 #include "defs.h"
  18 #include "input_mapping.h"
  19 #include "state.pb.h"
  20
  21 using namespace std;
  22 using namespace std::placeholders;
  23
  24 ALSAPool::ALSAPool()
  25 {
  26         should_quit_fd = eventfd(/*initval=*/0, /*flags=*/0);
  27         assert(should_quit_fd != -1);
  28 }
  29
  30 ALSAPool::~ALSAPool()
  31 {
  32         for (Device &device : devices) {
  33                 if (device.input != nullptr) {
  34                         device.input->stop_capture_thread();
  35                 }
  36         }
  37         should_quit = true;
  38         const uint64_t one = 1;
  39         write(should_quit_fd, &one, sizeof(one));
  40         inotify_thread.join();
  41
  42         while (retry_threads_running > 0) {
  43                 this_thread::sleep_for(std::chrono::milliseconds(100));
  44         }
  45 }
  46
  47 std::vector<ALSAPool::Device> ALSAPool::get_devices()
  48 {
  49         lock_guard<mutex> lock(mu);
  50         for (Device &device : devices) {
  51                 device.held = true;
  52         }
  53         return devices;
  54 }
  55
  56 void ALSAPool::hold_device(unsigned index)
  57 {
  58         lock_guard<mutex> lock(mu);
  59         assert(index < devices.size());
  60         devices[index].held = true;
  61 }
  62
  63 void ALSAPool::release_device(unsigned index)
  64 {
  65         lock_guard<mutex> lock(mu);
  66         if (index < devices.size()) {
  67                 devices[index].held = false;
  68         }
  69 }
  70
  71 void ALSAPool::enumerate_devices()
  72 {
  73         // Enumerate all cards.
  74         for (int card_index = -1; snd_card_next(&card_index) == 0 && card_index >= 0; ) {
  75                 char address[256];
  76                 snprintf(address, sizeof(address), "hw:%d", card_index);
  77
  78                 snd_ctl_t *ctl;
  79                 int err = snd_ctl_open(&ctl, address, 0);
  80                 if (err < 0) {
  81                         printf("%s: %s\n", address, snd_strerror(err));
  82                         continue;
  83                 }
  84                 unique_ptr<snd_ctl_t, decltype(snd_ctl_close)*> ctl_closer(ctl, snd_ctl_close);
  85
  86                 // Enumerate all devices on this card.
  87                 for (int dev_index = -1; snd_ctl_pcm_next_device(ctl, &dev_index) == 0 && dev_index >= 0; ) {
  88                         probe_device_with_retry(card_index, dev_index);
  89                 }
  90         }
  91 }
  92
  93 void ALSAPool::probe_device_with_retry(unsigned card_index, unsigned dev_index)
  94 {
  95         char address[256];
  96         snprintf(address, sizeof(address), "hw:%d,%d", card_index, dev_index);
  97
  98         lock_guard<mutex> lock(add_device_mutex);
  99         if (add_device_tries_left.count(address)) {
 100                 // Some thread is already busy retrying this,
 101                 // so just reset its count.
 102                 add_device_tries_left[address] = num_retries;
 103                 return;
 104         }
 105
 106         // Try (while still holding the lock) to add the device synchronously.
 107         ProbeResult result = probe_device_once(card_index, dev_index);
 108         if (result == ProbeResult::SUCCESS) {
 109                 return;
 110         } else if (result == ProbeResult::FAILURE) {
 111                 return;
 112         }
 113         assert(result == ProbeResult::DEFER);
 114
 115         // Add failed for whatever reason (probably just that the device
 116         // isn't up yet. Set up a count so that nobody else starts a thread,
 117         // then start it ourselves.
 118         fprintf(stderr, "Trying %s again in one second...\n", address);
 119         add_device_tries_left[address] = num_retries;
 120         ++retry_threads_running;
 121         thread(&ALSAPool::probe_device_retry_thread_func, this, card_index, dev_index).detach();
 122 }
 123
 124 void ALSAPool::probe_device_retry_thread_func(unsigned card_index, unsigned dev_index)
 125 {
 126         char address[256];
 127         snprintf(address, sizeof(address), "hw:%d,%d", card_index, dev_index);
 128
 129         for ( ;; ) {  // Termination condition within the loop.
 130                 sleep(1);
 131
 132                 // See if there are any retries left.
 133                 lock_guard<mutex> lock(add_device_mutex);
 134                 if (should_quit ||
 135                     !add_device_tries_left.count(address) ||
 136                     add_device_tries_left[address] == 0) {
 137                         add_device_tries_left.erase(address);
 138                         fprintf(stderr, "Giving up probe of %s.\n", address);
 139                         break;
 140                 }
 141
 142                 // Seemingly there were. Give it a try (we still hold the mutex).
 143                 ProbeResult result = probe_device_once(card_index, dev_index);
 144                 if (result == ProbeResult::SUCCESS) {
 145                         add_device_tries_left.erase(address);
 146                         fprintf(stderr, "Probe of %s succeeded.\n", address);
 147                         break;
 148                 } else if (result == ProbeResult::FAILURE || --add_device_tries_left[address] == 0) {
 149                         add_device_tries_left.erase(address);
 150                         fprintf(stderr, "Giving up probe of %s.\n", address);
 151                         break;
 152                 }
 153
 154                 // Failed again.
 155                 assert(result == ProbeResult::DEFER);
 156                 fprintf(stderr, "Trying %s again in one second (%d tries left)...\n",
 157                         address, add_device_tries_left[address]);
 158         }
 159
 160         --retry_threads_running;
 161 }
 162
 163 ALSAPool::ProbeResult ALSAPool::probe_device_once(unsigned card_index, unsigned dev_index)
 164 {
 165         char address[256];
 166         snprintf(address, sizeof(address), "hw:%d", card_index);
 167         snd_ctl_t *ctl;
 168         int err = snd_ctl_open(&ctl, address, 0);
 169         if (err < 0) {
 170                 printf("%s: %s\n", address, snd_strerror(err));
 171                 return ALSAPool::ProbeResult::DEFER;
 172         }
 173         unique_ptr<snd_ctl_t, decltype(snd_ctl_close)*> ctl_closer(ctl, snd_ctl_close);
 174
 175         snd_pcm_info_t *pcm_info;
 176         snd_pcm_info_alloca(&pcm_info);
 177         snd_pcm_info_set_device(pcm_info, dev_index);
 178         snd_pcm_info_set_subdevice(pcm_info, 0);
 179         snd_pcm_info_set_stream(pcm_info, SND_PCM_STREAM_CAPTURE);
 180         if (snd_ctl_pcm_info(ctl, pcm_info) < 0) {
 181                 // Not available for capture.
 182                 printf("%s: Not available for capture.\n", address);
 183                 return ALSAPool::ProbeResult::DEFER;
 184         }
 185
 186         snprintf(address, sizeof(address), "hw:%d,%d", card_index, dev_index);
 187
 188         unsigned num_channels = 0;
 189
 190         // Find all channel maps for this device, and pick out the one
 191         // with the most channels.
 192         snd_pcm_chmap_query_t **cmaps = snd_pcm_query_chmaps_from_hw(card_index, dev_index, 0, SND_PCM_STREAM_CAPTURE);
 193         if (cmaps != nullptr) {
 194                 for (snd_pcm_chmap_query_t **ptr = cmaps; *ptr; ++ptr) {
 195                         num_channels = max(num_channels, (*ptr)->map.channels);
 196                 }
 197                 snd_pcm_free_chmaps(cmaps);
 198         }
 199         if (num_channels == 0) {
 200                 // Device had no channel maps. We need to open it to query.
 201                 // TODO: Do this asynchronously.
 202                 snd_pcm_t *pcm_handle;
 203                 int err = snd_pcm_open(&pcm_handle, address, SND_PCM_STREAM_CAPTURE, 0);
 204                 if (err < 0) {
 205                         printf("%s: %s\n", address, snd_strerror(err));
 206                         return ALSAPool::ProbeResult::DEFER;
 207                 }
 208                 snd_pcm_hw_params_t *hw_params;
 209                 snd_pcm_hw_params_alloca(&hw_params);
 210                 unsigned sample_rate;
 211                 if (!ALSAInput::set_base_params(address, pcm_handle, hw_params, &sample_rate)) {
 212                         snd_pcm_close(pcm_handle);
 213                         return ALSAPool::ProbeResult::DEFER;
 214                 }
 215                 err = snd_pcm_hw_params_get_channels_max(hw_params, &num_channels);
 216                 if (err < 0) {
 217                         fprintf(stderr, "[%s] snd_pcm_hw_params_get_channels_max(): %s\n",
 218                                 address, snd_strerror(err));
 219                         snd_pcm_close(pcm_handle);
 220                         return ALSAPool::ProbeResult::DEFER;
 221                 }
 222                 snd_pcm_close(pcm_handle);
 223         }
 224
 225         if (num_channels == 0) {
 226                 printf("%s: No channel maps with channels\n", address);
 227                 return ALSAPool::ProbeResult::FAILURE;
 228         }
 229
 230         snd_ctl_card_info_t *card_info;
 231         snd_ctl_card_info_alloca(&card_info);
 232         snd_ctl_card_info(ctl, card_info);
 233
 234         string name = snd_ctl_card_info_get_name(card_info);
 235         string info = snd_pcm_info_get_name(pcm_info);
 236
 237         unsigned internal_dev_index;
 238         string display_name;
 239         {
 240                 lock_guard<mutex> lock(mu);
 241                 internal_dev_index = find_free_device_index(name, info, num_channels, address);
 242                 devices[internal_dev_index].address = address;
 243                 devices[internal_dev_index].name = name;
 244                 devices[internal_dev_index].info = info;
 245                 devices[internal_dev_index].num_channels = num_channels;
 246                 // Note: Purposefully does not overwrite held.
 247
 248                 display_name = devices[internal_dev_index].display_name();
 249         }
 250
 251         fprintf(stderr, "%s: Probed successfully.\n", address);
 252
 253         reset_device(internal_dev_index);  // Restarts it if it is held (ie., we just replaced a dead card).
 254
 255         DeviceSpec spec{InputSourceType::ALSA_INPUT, internal_dev_index};
 256         global_audio_mixer->set_display_name(spec, display_name);
 257         global_audio_mixer->trigger_state_changed_callback();
 258
 259         return ALSAPool::ProbeResult::SUCCESS;
 260 }
 261
 262 void ALSAPool::unplug_device(unsigned card_index, unsigned dev_index)
 263 {
 264         char address[256];
 265         snprintf(address, sizeof(address), "hw:%d,%d", card_index, dev_index);
 266         for (unsigned i = 0; i < devices.size(); ++i) {
 267                 if (devices[i].state != Device::State::EMPTY &&
 268                     devices[i].state != Device::State::DEAD &&
 269                     devices[i].address == address) {
 270                         free_card(i);
 271                 }
 272         }
 273 }
 274
 275 void ALSAPool::init()
 276 {
 277         inotify_thread = thread(&ALSAPool::inotify_thread_func, this);
 278         enumerate_devices();
 279 }
 280
 281 void ALSAPool::inotify_thread_func()
 282 {
 283         int inotify_fd = inotify_init();
 284         if (inotify_fd == -1) {
 285                 perror("inotify_init()");
 286                 fprintf(stderr, "No hotplug of ALSA devices available.\n");
 287                 return;
 288         }
 289
 290         int watch_fd = inotify_add_watch(inotify_fd, "/dev/snd", IN_MOVE | IN_CREATE | IN_DELETE);
 291         if (watch_fd == -1) {
 292                 perror("inotify_add_watch()");
 293                 fprintf(stderr, "No hotplug of ALSA devices available.\n");
 294                 close(inotify_fd);
 295                 return;
 296         }
 297
 298         int size = sizeof(inotify_event) + NAME_MAX + 1;
 299         unique_ptr<char[]> buf(new char[size]);
 300         while (!should_quit) {
 301                 pollfd fds[2];
 302                 fds[0].fd = inotify_fd;
 303                 fds[0].events = POLLIN;
 304                 fds[0].revents = 0;
 305                 fds[1].fd = should_quit_fd;
 306                 fds[1].events = POLLIN;
 307                 fds[1].revents = 0;
 308
 309                 int ret = poll(fds, 2, -1);
 310                 if (ret == -1) {
 311                         if (errno == EINTR) {
 312                                 continue;
 313                         } else {
 314                                 perror("poll(inotify_fd)");
 315                                 return;
 316                         }
 317                 }
 318                 if (ret == 0) {
 319                         continue;
 320                 }
 321
 322                 if (fds[1].revents) break;  // should_quit_fd asserted.
 323
 324                 ret = read(inotify_fd, buf.get(), size);
 325                 if (ret == -1) {
 326                         if (errno == EINTR) {
 327                                 continue;
 328                         } else {
 329                                 perror("read(inotify_fd)");
 330                                 close(watch_fd);
 331                                 close(inotify_fd);
 332                                 return;
 333                         }
 334                 }
 335                 if (ret < int(sizeof(inotify_event))) {
 336                         fprintf(stderr, "inotify read unexpectedly returned %d, giving up hotplug of ALSA devices.\n",
 337                                 int(ret));
 338                         close(watch_fd);
 339                         close(inotify_fd);
 340                         return;
 341                 }
 342
 343                 for (int i = 0; i < ret; ) {
 344                         const inotify_event *event = reinterpret_cast<const inotify_event *>(&buf[i]);
 345                         i += sizeof(inotify_event) + event->len;
 346
 347                         if (event->mask & IN_Q_OVERFLOW) {
 348                                 fprintf(stderr, "WARNING: inotify overflowed, may lose ALSA hotplug events.\n");
 349                                 continue;
 350                         }
 351                         unsigned card, device;
 352                         char type;
 353                         if (sscanf(event->name, "pcmC%uD%u%c", &card, &device, &type) == 3 && type == 'c') {
 354                                 if (event->mask & (IN_MOVED_FROM | IN_DELETE)) {
 355                                         printf("Deleted capture device: Card %u, device %u\n", card, device);
 356                                         unplug_device(card, device);
 357                                 }
 358                                 if (event->mask & (IN_MOVED_TO | IN_CREATE)) {
 359                                         printf("Adding capture device: Card %u, device %u\n", card, device);
 360                                         probe_device_with_retry(card, device);
 361                                 }
 362                         }
 363                 }
 364         }
 365         close(watch_fd);
 366         close(inotify_fd);
 367         close(should_quit_fd);
 368 }
 369
 370 void ALSAPool::reset_device(unsigned index)
 371 {
 372         lock_guard<mutex> lock(mu);
 373         Device *device = &devices[index];
 374         if (inputs[index] != nullptr) {
 375                 inputs[index]->stop_capture_thread();
 376         }
 377         if (!device->held) {
 378                 inputs[index].reset();
 379         } else {
 380                 // TODO: Put on a background thread instead of locking?
 381                 auto callback = bind(&AudioMixer::add_audio, global_audio_mixer, DeviceSpec{InputSourceType::ALSA_INPUT, index}, _1, _2, _3, _4);
 382                 inputs[index].reset(new ALSAInput(device->address.c_str(), OUTPUT_FREQUENCY, device->num_channels, callback, this, index));
 383                 inputs[index]->start_capture_thread();
 384         }
 385         device->input = inputs[index].get();
 386 }
 387
 388 unsigned ALSAPool::get_capture_frequency(unsigned index)
 389 {
 390         lock_guard<mutex> lock(mu);
 391         assert(devices[index].held);
 392         if (devices[index].input)
 393                 return devices[index].input->get_sample_rate();
 394         else
 395                 return OUTPUT_FREQUENCY;
 396 }
 397
 398 ALSAPool::Device::State ALSAPool::get_card_state(unsigned index)
 399 {
 400         lock_guard<mutex> lock(mu);
 401         assert(devices[index].held);
 402         return devices[index].state;
 403 }
 404
 405 void ALSAPool::set_card_state(unsigned index, ALSAPool::Device::State state)
 406 {
 407         {
 408                 lock_guard<mutex> lock(mu);
 409                 devices[index].state = state;
 410         }
 411
 412         DeviceSpec spec{InputSourceType::ALSA_INPUT, index};
 413         bool silence = (state != ALSAPool::Device::State::RUNNING);
 414         while (!global_audio_mixer->silence_card(spec, silence))
 415                 ;
 416         global_audio_mixer->trigger_state_changed_callback();
 417 }
 418
 419 unsigned ALSAPool::find_free_device_index(const string &name, const string &info, unsigned num_channels, const string &address)
 420 {
 421         // First try to find an exact match on a dead card.
 422         for (unsigned i = 0; i < devices.size(); ++i) {
 423                 if (devices[i].state == Device::State::DEAD &&
 424                     devices[i].address == address &&
 425                     devices[i].name == name &&
 426                     devices[i].info == info &&
 427                     devices[i].num_channels == num_channels) {
 428                         devices[i].state = Device::State::READY;
 429                         return i;
 430                 }
 431         }
 432
 433         // Then try to find a match on everything but the address
 434         // (probably that devices were plugged back in a different order).
 435         // If we have two cards that are equal, this might get them mixed up,
 436         // but we don't have anything better.
 437         for (unsigned i = 0; i < devices.size(); ++i) {
 438                 if (devices[i].state == Device::State::DEAD &&
 439                     devices[i].name == name &&
 440                     devices[i].info == info &&
 441                     devices[i].num_channels == num_channels) {
 442                         devices[i].state = Device::State::READY;
 443                         return i;
 444                 }
 445         }
 446
 447         // OK, so we didn't find a match; see if there are any empty slots.
 448         for (unsigned i = 0; i < devices.size(); ++i) {
 449                 if (devices[i].state == Device::State::EMPTY) {
 450                         devices[i].state = Device::State::READY;
 451                         devices[i].held = false;
 452                         return i;
 453                 }
 454         }
 455
 456         // Failing that, we just insert the new device at the end.
 457         Device new_dev;
 458         new_dev.state = Device::State::READY;
 459         new_dev.held = false;
 460         devices.push_back(new_dev);
 461         inputs.emplace_back(nullptr);
 462         return devices.size() - 1;
 463 }
 464
 465 unsigned ALSAPool::create_dead_card(const string &name, const string &info, unsigned num_channels)
 466 {
 467         lock_guard<mutex> lock(mu);
 468
 469         // See if there are any empty slots. If not, insert one at the end.
 470         vector<Device>::iterator free_device =
 471                 find_if(devices.begin(), devices.end(),
 472                         [](const Device &device) { return device.state == Device::State::EMPTY; });
 473         if (free_device == devices.end()) {
 474                 devices.push_back(Device());
 475                 inputs.emplace_back(nullptr);
 476                 free_device = devices.end() - 1;
 477         }
 478
 479         free_device->state = Device::State::DEAD;
 480         free_device->name = name;
 481         free_device->info = info;
 482         free_device->num_channels = num_channels;
 483         free_device->held = true;
 484
 485         return distance(devices.begin(), free_device);
 486 }
 487
 488 void ALSAPool::serialize_device(unsigned index, DeviceSpecProto *serialized)
 489 {
 490         lock_guard<mutex> lock(mu);
 491         assert(index < devices.size());
 492         assert(devices[index].held);
 493         serialized->set_type(DeviceSpecProto::ALSA_INPUT);
 494         serialized->set_index(index);
 495         serialized->set_display_name(devices[index].display_name());
 496         serialized->set_alsa_name(devices[index].name);
 497         serialized->set_alsa_info(devices[index].info);
 498         serialized->set_num_channels(devices[index].num_channels);
 499         serialized->set_address(devices[index].address);
 500 }
 501
 502 void ALSAPool::free_card(unsigned index)
 503 {
 504         DeviceSpec spec{InputSourceType::ALSA_INPUT, index};
 505         while (!global_audio_mixer->silence_card(spec, true))
 506                 ;
 507
 508         {
 509                 lock_guard<mutex> lock(mu);
 510                 if (devices[index].held) {
 511                         devices[index].state = Device::State::DEAD;
 512                 } else {
 513                         devices[index].state = Device::State::EMPTY;
 514                         inputs[index].reset();
 515                 }
 516                 while (!devices.empty() && devices.back().state == Device::State::EMPTY) {
 517                         devices.pop_back();
 518                         inputs.pop_back();
 519                 }
 520         }
 521
 522         global_audio_mixer->trigger_state_changed_callback();
 523 }