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

   1 #include "alsa_pool.h"
   2
   3 #include <alsa/asoundlib.h>
   4 #include <assert.h>
   5 #include <errno.h>
   6 #include <limits.h>
   7 #include <poll.h>
   8 #include <stdint.h>
   9 #include <stdio.h>
  10 #include <sys/eventfd.h>
  11 #include <sys/inotify.h>
  12 #include <unistd.h>
  13 #include <algorithm>
  14 #include <chrono>
  15 #include <functional>
  16 #include <iterator>
  17 #include <memory>
  18 #include <ratio>
  19
  20 #include "alsa_input.h"
  21 #include "audio_mixer.h"
  22 #include "defs.h"
  23 #include "input_mapping.h"
  24 #include "state.pb.h"
  25
  26 using namespace std;
  27 using namespace std::placeholders;
  28
  29 ALSAPool::ALSAPool()
  30 {
  31         should_quit_fd = eventfd(/*initval=*/0, /*flags=*/0);
  32         assert(should_quit_fd != -1);
  33 }
  34
  35 ALSAPool::~ALSAPool()
  36 {
  37         for (Device &device : devices) {
  38                 if (device.input != nullptr) {
  39                         device.input->stop_capture_thread();
  40                 }
  41         }
  42         should_quit = true;
  43         const uint64_t one = 1;
  44         write(should_quit_fd, &one, sizeof(one));
  45         inotify_thread.join();
  46
  47         while (retry_threads_running > 0) {
  48                 this_thread::sleep_for(std::chrono::milliseconds(100));
  49         }
  50 }
  51
  52 std::vector<ALSAPool::Device> ALSAPool::get_devices()
  53 {
  54         lock_guard<mutex> lock(mu);
  55         for (Device &device : devices) {
  56                 device.held = true;
  57         }
  58         return devices;
  59 }
  60
  61 void ALSAPool::hold_device(unsigned index)
  62 {
  63         lock_guard<mutex> lock(mu);
  64         assert(index < devices.size());
  65         devices[index].held = true;
  66 }
  67
  68 void ALSAPool::release_device(unsigned index)
  69 {
  70         lock_guard<mutex> lock(mu);
  71         if (index < devices.size()) {
  72                 devices[index].held = false;
  73         }
  74 }
  75
  76 void ALSAPool::enumerate_devices()
  77 {
  78         // Enumerate all cards.
  79         for (int card_index = -1; snd_card_next(&card_index) == 0 && card_index >= 0; ) {
  80                 char address[256];
  81                 snprintf(address, sizeof(address), "hw:%d", card_index);
  82
  83                 snd_ctl_t *ctl;
  84                 int err = snd_ctl_open(&ctl, address, 0);
  85                 if (err < 0) {
  86                         printf("%s: %s\n", address, snd_strerror(err));
  87                         continue;
  88                 }
  89                 unique_ptr<snd_ctl_t, decltype(snd_ctl_close)*> ctl_closer(ctl, snd_ctl_close);
  90
  91                 // Enumerate all devices on this card.
  92                 for (int dev_index = -1; snd_ctl_pcm_next_device(ctl, &dev_index) == 0 && dev_index >= 0; ) {
  93                         probe_device_with_retry(card_index, dev_index);
  94                 }
  95         }
  96 }
  97
  98 void ALSAPool::probe_device_with_retry(unsigned card_index, unsigned dev_index)
  99 {
 100         char address[256];
 101         snprintf(address, sizeof(address), "hw:%d,%d", card_index, dev_index);
 102
 103         lock_guard<mutex> lock(add_device_mutex);
 104         if (add_device_tries_left.count(address)) {
 105                 // Some thread is already busy retrying this,
 106                 // so just reset its count.
 107                 add_device_tries_left[address] = num_retries;
 108                 return;
 109         }
 110
 111         // Try (while still holding the lock) to add the device synchronously.
 112         ProbeResult result = probe_device_once(card_index, dev_index);
 113         if (result == ProbeResult::SUCCESS) {
 114                 return;
 115         } else if (result == ProbeResult::FAILURE) {
 116                 return;
 117         }
 118         assert(result == ProbeResult::DEFER);
 119
 120         // Add failed for whatever reason (probably just that the device
 121         // isn't up yet. Set up a count so that nobody else starts a thread,
 122         // then start it ourselves.
 123         fprintf(stderr, "Trying %s again in one second...\n", address);
 124         add_device_tries_left[address] = num_retries;
 125         ++retry_threads_running;
 126         thread(&ALSAPool::probe_device_retry_thread_func, this, card_index, dev_index).detach();
 127 }
 128
 129 void ALSAPool::probe_device_retry_thread_func(unsigned card_index, unsigned dev_index)
 130 {
 131         char address[256];
 132         snprintf(address, sizeof(address), "hw:%d,%d", card_index, dev_index);
 133
 134         for ( ;; ) {  // Termination condition within the loop.
 135                 sleep(1);
 136
 137                 // See if there are any retries left.
 138                 lock_guard<mutex> lock(add_device_mutex);
 139                 if (should_quit ||
 140                     !add_device_tries_left.count(address) ||
 141                     add_device_tries_left[address] == 0) {
 142                         add_device_tries_left.erase(address);
 143                         fprintf(stderr, "Giving up probe of %s.\n", address);
 144                         break;
 145                 }
 146
 147                 // Seemingly there were. Give it a try (we still hold the mutex).
 148                 ProbeResult result = probe_device_once(card_index, dev_index);
 149                 if (result == ProbeResult::SUCCESS) {
 150                         add_device_tries_left.erase(address);
 151                         fprintf(stderr, "Probe of %s succeeded.\n", address);
 152                         break;
 153                 } else if (result == ProbeResult::FAILURE || --add_device_tries_left[address] == 0) {
 154                         add_device_tries_left.erase(address);
 155                         fprintf(stderr, "Giving up probe of %s.\n", address);
 156                         break;
 157                 }
 158
 159                 // Failed again.
 160                 assert(result == ProbeResult::DEFER);
 161                 fprintf(stderr, "Trying %s again in one second (%d tries left)...\n",
 162                         address, add_device_tries_left[address]);
 163         }
 164
 165         --retry_threads_running;
 166 }
 167
 168 ALSAPool::ProbeResult ALSAPool::probe_device_once(unsigned card_index, unsigned dev_index)
 169 {
 170         char address[256];
 171         snprintf(address, sizeof(address), "hw:%d", card_index);
 172         snd_ctl_t *ctl;
 173         int err = snd_ctl_open(&ctl, address, 0);
 174         if (err < 0) {
 175                 printf("%s: %s\n", address, snd_strerror(err));
 176                 return ALSAPool::ProbeResult::DEFER;
 177         }
 178         unique_ptr<snd_ctl_t, decltype(snd_ctl_close)*> ctl_closer(ctl, snd_ctl_close);
 179
 180         snd_pcm_info_t *pcm_info;
 181         snd_pcm_info_alloca(&pcm_info);
 182         snd_pcm_info_set_device(pcm_info, dev_index);
 183         snd_pcm_info_set_subdevice(pcm_info, 0);
 184         snd_pcm_info_set_stream(pcm_info, SND_PCM_STREAM_CAPTURE);
 185         if (snd_ctl_pcm_info(ctl, pcm_info) < 0) {
 186                 // Not available for capture.
 187                 printf("%s: Not available for capture.\n", address);
 188                 return ALSAPool::ProbeResult::DEFER;
 189         }
 190
 191         snprintf(address, sizeof(address), "hw:%d,%d", card_index, dev_index);
 192
 193         unsigned num_channels = 0;
 194
 195         // Find all channel maps for this device, and pick out the one
 196         // with the most channels.
 197         snd_pcm_chmap_query_t **cmaps = snd_pcm_query_chmaps_from_hw(card_index, dev_index, 0, SND_PCM_STREAM_CAPTURE);
 198         if (cmaps != nullptr) {
 199                 for (snd_pcm_chmap_query_t **ptr = cmaps; *ptr; ++ptr) {
 200                         num_channels = max(num_channels, (*ptr)->map.channels);
 201                 }
 202                 snd_pcm_free_chmaps(cmaps);
 203         }
 204         if (num_channels == 0) {
 205                 // Device had no channel maps. We need to open it to query.
 206                 // TODO: Do this asynchronously.
 207                 snd_pcm_t *pcm_handle;
 208                 int err = snd_pcm_open(&pcm_handle, address, SND_PCM_STREAM_CAPTURE, 0);
 209                 if (err < 0) {
 210                         printf("%s: %s\n", address, snd_strerror(err));
 211                         return ALSAPool::ProbeResult::DEFER;
 212                 }
 213                 snd_pcm_hw_params_t *hw_params;
 214                 snd_pcm_hw_params_alloca(&hw_params);
 215                 unsigned sample_rate;
 216                 if (!ALSAInput::set_base_params(address, pcm_handle, hw_params, &sample_rate)) {
 217                         snd_pcm_close(pcm_handle);
 218                         return ALSAPool::ProbeResult::DEFER;
 219                 }
 220                 err = snd_pcm_hw_params_get_channels_max(hw_params, &num_channels);
 221                 if (err < 0) {
 222                         fprintf(stderr, "[%s] snd_pcm_hw_params_get_channels_max(): %s\n",
 223                                 address, snd_strerror(err));
 224                         snd_pcm_close(pcm_handle);
 225                         return ALSAPool::ProbeResult::DEFER;
 226                 }
 227                 snd_pcm_close(pcm_handle);
 228         }
 229
 230         if (num_channels == 0) {
 231                 printf("%s: No channel maps with channels\n", address);
 232                 return ALSAPool::ProbeResult::FAILURE;
 233         }
 234
 235         snd_ctl_card_info_t *card_info;
 236         snd_ctl_card_info_alloca(&card_info);
 237         snd_ctl_card_info(ctl, card_info);
 238
 239         string name = snd_ctl_card_info_get_name(card_info);
 240         string info = snd_pcm_info_get_name(pcm_info);
 241
 242         unsigned internal_dev_index;
 243         string display_name;
 244         {
 245                 lock_guard<mutex> lock(mu);
 246                 internal_dev_index = find_free_device_index(name, info, num_channels, address);
 247                 devices[internal_dev_index].address = address;
 248                 devices[internal_dev_index].name = name;
 249                 devices[internal_dev_index].info = info;
 250                 devices[internal_dev_index].num_channels = num_channels;
 251                 // Note: Purposefully does not overwrite held.
 252
 253                 display_name = devices[internal_dev_index].display_name();
 254         }
 255
 256         fprintf(stderr, "%s: Probed successfully.\n", address);
 257
 258         reset_device(internal_dev_index);  // Restarts it if it is held (ie., we just replaced a dead card).
 259
 260         DeviceSpec spec{InputSourceType::ALSA_INPUT, internal_dev_index};
 261         global_audio_mixer->set_display_name(spec, display_name);
 262         global_audio_mixer->trigger_state_changed_callback();
 263
 264         return ALSAPool::ProbeResult::SUCCESS;
 265 }
 266
 267 void ALSAPool::unplug_device(unsigned card_index, unsigned dev_index)
 268 {
 269         char address[256];
 270         snprintf(address, sizeof(address), "hw:%d,%d", card_index, dev_index);
 271         for (unsigned i = 0; i < devices.size(); ++i) {
 272                 if (devices[i].state != Device::State::EMPTY &&
 273                     devices[i].state != Device::State::DEAD &&
 274                     devices[i].address == address) {
 275                         free_card(i);
 276                 }
 277         }
 278 }
 279
 280 void ALSAPool::init()
 281 {
 282         inotify_thread = thread(&ALSAPool::inotify_thread_func, this);
 283         enumerate_devices();
 284 }
 285
 286 void ALSAPool::inotify_thread_func()
 287 {
 288         int inotify_fd = inotify_init();
 289         if (inotify_fd == -1) {
 290                 perror("inotify_init()");
 291                 fprintf(stderr, "No hotplug of ALSA devices available.\n");
 292                 return;
 293         }
 294
 295         int watch_fd = inotify_add_watch(inotify_fd, "/dev/snd", IN_MOVE | IN_CREATE | IN_DELETE);
 296         if (watch_fd == -1) {
 297                 perror("inotify_add_watch()");
 298                 fprintf(stderr, "No hotplug of ALSA devices available.\n");
 299                 close(inotify_fd);
 300                 return;
 301         }
 302
 303         int size = sizeof(inotify_event) + NAME_MAX + 1;
 304         unique_ptr<char[]> buf(new char[size]);
 305         while (!should_quit) {
 306                 pollfd fds[2];
 307                 fds[0].fd = inotify_fd;
 308                 fds[0].events = POLLIN;
 309                 fds[0].revents = 0;
 310                 fds[1].fd = should_quit_fd;
 311                 fds[1].events = POLLIN;
 312                 fds[1].revents = 0;
 313
 314                 int ret = poll(fds, 2, -1);
 315                 if (ret == -1) {
 316                         if (errno == EINTR) {
 317                                 continue;
 318                         } else {
 319                                 perror("poll(inotify_fd)");
 320                                 return;
 321                         }
 322                 }
 323                 if (ret == 0) {
 324                         continue;
 325                 }
 326
 327                 if (fds[1].revents) break;  // should_quit_fd asserted.
 328
 329                 ret = read(inotify_fd, buf.get(), size);
 330                 if (ret == -1) {
 331                         if (errno == EINTR) {
 332                                 continue;
 333                         } else {
 334                                 perror("read(inotify_fd)");
 335                                 close(watch_fd);
 336                                 close(inotify_fd);
 337                                 return;
 338                         }
 339                 }
 340                 if (ret < int(sizeof(inotify_event))) {
 341                         fprintf(stderr, "inotify read unexpectedly returned %d, giving up hotplug of ALSA devices.\n",
 342                                 int(ret));
 343                         close(watch_fd);
 344                         close(inotify_fd);
 345                         return;
 346                 }
 347
 348                 for (int i = 0; i < ret; ) {
 349                         const inotify_event *event = reinterpret_cast<const inotify_event *>(&buf[i]);
 350                         i += sizeof(inotify_event) + event->len;
 351
 352                         if (event->mask & IN_Q_OVERFLOW) {
 353                                 fprintf(stderr, "WARNING: inotify overflowed, may lose ALSA hotplug events.\n");
 354                                 continue;
 355                         }
 356                         unsigned card, device;
 357                         char type;
 358                         if (sscanf(event->name, "pcmC%uD%u%c", &card, &device, &type) == 3 && type == 'c') {
 359                                 if (event->mask & (IN_MOVED_FROM | IN_DELETE)) {
 360                                         printf("Deleted capture device: Card %u, device %u\n", card, device);
 361                                         unplug_device(card, device);
 362                                 }
 363                                 if (event->mask & (IN_MOVED_TO | IN_CREATE)) {
 364                                         printf("Adding capture device: Card %u, device %u\n", card, device);
 365                                         probe_device_with_retry(card, device);
 366                                 }
 367                         }
 368                 }
 369         }
 370         close(watch_fd);
 371         close(inotify_fd);
 372         close(should_quit_fd);
 373 }
 374
 375 void ALSAPool::reset_device(unsigned index)
 376 {
 377         lock_guard<mutex> lock(mu);
 378         Device *device = &devices[index];
 379         if (inputs[index] != nullptr) {
 380                 inputs[index]->stop_capture_thread();
 381         }
 382         if (!device->held) {
 383                 inputs[index].reset();
 384         } else {
 385                 // TODO: Put on a background thread instead of locking?
 386                 auto callback = bind(&AudioMixer::add_audio, global_audio_mixer, DeviceSpec{InputSourceType::ALSA_INPUT, index}, _1, _2, _3, _4);
 387                 inputs[index].reset(new ALSAInput(device->address.c_str(), OUTPUT_FREQUENCY, device->num_channels, callback, this, index));
 388                 inputs[index]->start_capture_thread();
 389         }
 390         device->input = inputs[index].get();
 391 }
 392
 393 unsigned ALSAPool::get_capture_frequency(unsigned index)
 394 {
 395         lock_guard<mutex> lock(mu);
 396         assert(devices[index].held);
 397         if (devices[index].input)
 398                 return devices[index].input->get_sample_rate();
 399         else
 400                 return OUTPUT_FREQUENCY;
 401 }
 402
 403 ALSAPool::Device::State ALSAPool::get_card_state(unsigned index)
 404 {
 405         lock_guard<mutex> lock(mu);
 406         assert(devices[index].held);
 407         return devices[index].state;
 408 }
 409
 410 void ALSAPool::set_card_state(unsigned index, ALSAPool::Device::State state)
 411 {
 412         {
 413                 lock_guard<mutex> lock(mu);
 414                 devices[index].state = state;
 415         }
 416
 417         DeviceSpec spec{InputSourceType::ALSA_INPUT, index};
 418         bool silence = (state != ALSAPool::Device::State::RUNNING);
 419         while (!global_audio_mixer->silence_card(spec, silence))
 420                 ;
 421         global_audio_mixer->trigger_state_changed_callback();
 422 }
 423
 424 unsigned ALSAPool::find_free_device_index(const string &name, const string &info, unsigned num_channels, const string &address)
 425 {
 426         // First try to find an exact match on a dead card.
 427         for (unsigned i = 0; i < devices.size(); ++i) {
 428                 if (devices[i].state == Device::State::DEAD &&
 429                     devices[i].address == address &&
 430                     devices[i].name == name &&
 431                     devices[i].info == info &&
 432                     devices[i].num_channels == num_channels) {
 433                         devices[i].state = Device::State::READY;
 434                         return i;
 435                 }
 436         }
 437
 438         // Then try to find a match on everything but the address
 439         // (probably that devices were plugged back in a different order).
 440         // If we have two cards that are equal, this might get them mixed up,
 441         // but we don't have anything better.
 442         for (unsigned i = 0; i < devices.size(); ++i) {
 443                 if (devices[i].state == Device::State::DEAD &&
 444                     devices[i].name == name &&
 445                     devices[i].info == info &&
 446                     devices[i].num_channels == num_channels) {
 447                         devices[i].state = Device::State::READY;
 448                         return i;
 449                 }
 450         }
 451
 452         // OK, so we didn't find a match; see if there are any empty slots.
 453         for (unsigned i = 0; i < devices.size(); ++i) {
 454                 if (devices[i].state == Device::State::EMPTY) {
 455                         devices[i].state = Device::State::READY;
 456                         devices[i].held = false;
 457                         return i;
 458                 }
 459         }
 460
 461         // Failing that, we just insert the new device at the end.
 462         Device new_dev;
 463         new_dev.state = Device::State::READY;
 464         new_dev.held = false;
 465         devices.push_back(new_dev);
 466         inputs.emplace_back(nullptr);
 467         return devices.size() - 1;
 468 }
 469
 470 unsigned ALSAPool::create_dead_card(const string &name, const string &info, unsigned num_channels)
 471 {
 472         lock_guard<mutex> lock(mu);
 473
 474         // See if there are any empty slots. If not, insert one at the end.
 475         vector<Device>::iterator free_device =
 476                 find_if(devices.begin(), devices.end(),
 477                         [](const Device &device) { return device.state == Device::State::EMPTY; });
 478         if (free_device == devices.end()) {
 479                 devices.push_back(Device());
 480                 inputs.emplace_back(nullptr);
 481                 free_device = devices.end() - 1;
 482         }
 483
 484         free_device->state = Device::State::DEAD;
 485         free_device->name = name;
 486         free_device->info = info;
 487         free_device->num_channels = num_channels;
 488         free_device->held = true;
 489
 490         return distance(devices.begin(), free_device);
 491 }
 492
 493 void ALSAPool::serialize_device(unsigned index, DeviceSpecProto *serialized)
 494 {
 495         lock_guard<mutex> lock(mu);
 496         assert(index < devices.size());
 497         assert(devices[index].held);
 498         serialized->set_type(DeviceSpecProto::ALSA_INPUT);
 499         serialized->set_index(index);
 500         serialized->set_display_name(devices[index].display_name());
 501         serialized->set_alsa_name(devices[index].name);
 502         serialized->set_alsa_info(devices[index].info);
 503         serialized->set_num_channels(devices[index].num_channels);
 504         serialized->set_address(devices[index].address);
 505 }
 506
 507 void ALSAPool::free_card(unsigned index)
 508 {
 509         DeviceSpec spec{InputSourceType::ALSA_INPUT, index};
 510         while (!global_audio_mixer->silence_card(spec, true))
 511                 ;
 512
 513         {
 514                 lock_guard<mutex> lock(mu);
 515                 if (devices[index].held) {
 516                         devices[index].state = Device::State::DEAD;
 517                 } else {
 518                         devices[index].state = Device::State::EMPTY;
 519                         inputs[index].reset();
 520                 }
 521                 while (!devices.empty() && devices.back().state == Device::State::EMPTY) {
 522                         devices.pop_back();
 523                         inputs.pop_back();
 524                 }
 525         }
 526
 527         global_audio_mixer->trigger_state_changed_callback();
 528 }