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         if (write(should_quit_fd, &one, sizeof(one)) != sizeof(one)) {
  45                 perror("write(should_quit_fd)");
  46                 exit(1);
  47         }
  48         inotify_thread.join();
  49
  50         while (retry_threads_running > 0) {
  51                 this_thread::sleep_for(std::chrono::milliseconds(100));
  52         }
  53 }
  54
  55 std::vector<ALSAPool::Device> ALSAPool::get_devices()
  56 {
  57         lock_guard<mutex> lock(mu);
  58         for (Device &device : devices) {
  59                 device.held = true;
  60         }
  61         return devices;
  62 }
  63
  64 void ALSAPool::hold_device(unsigned index)
  65 {
  66         lock_guard<mutex> lock(mu);
  67         assert(index < devices.size());
  68         devices[index].held = true;
  69 }
  70
  71 void ALSAPool::release_device(unsigned index)
  72 {
  73         lock_guard<mutex> lock(mu);
  74         if (index < devices.size()) {
  75                 devices[index].held = false;
  76         }
  77 }
  78
  79 void ALSAPool::enumerate_devices()
  80 {
  81         // Enumerate all cards.
  82         for (int card_index = -1; snd_card_next(&card_index) == 0 && card_index >= 0; ) {
  83                 char address[256];
  84                 snprintf(address, sizeof(address), "hw:%d", card_index);
  85
  86                 snd_ctl_t *ctl;
  87                 int err = snd_ctl_open(&ctl, address, 0);
  88                 if (err < 0) {
  89                         printf("%s: %s\n", address, snd_strerror(err));
  90                         continue;
  91                 }
  92                 unique_ptr<snd_ctl_t, decltype(snd_ctl_close)*> ctl_closer(ctl, snd_ctl_close);
  93
  94                 // Enumerate all devices on this card.
  95                 for (int dev_index = -1; snd_ctl_pcm_next_device(ctl, &dev_index) == 0 && dev_index >= 0; ) {
  96                         probe_device_with_retry(card_index, dev_index);
  97                 }
  98         }
  99 }
 100
 101 void ALSAPool::probe_device_with_retry(unsigned card_index, unsigned dev_index)
 102 {
 103         char address[256];
 104         snprintf(address, sizeof(address), "hw:%d,%d", card_index, dev_index);
 105
 106         lock_guard<mutex> lock(add_device_mutex);
 107         if (add_device_tries_left.count(address)) {
 108                 // Some thread is already busy retrying this,
 109                 // so just reset its count.
 110                 add_device_tries_left[address] = num_retries;
 111                 return;
 112         }
 113
 114         // Try (while still holding the lock) to add the device synchronously.
 115         ProbeResult result = probe_device_once(card_index, dev_index);
 116         if (result == ProbeResult::SUCCESS) {
 117                 return;
 118         } else if (result == ProbeResult::FAILURE) {
 119                 return;
 120         }
 121         assert(result == ProbeResult::DEFER);
 122
 123         // Add failed for whatever reason (probably just that the device
 124         // isn't up yet. Set up a count so that nobody else starts a thread,
 125         // then start it ourselves.
 126         fprintf(stderr, "Trying %s again in one second...\n", address);
 127         add_device_tries_left[address] = num_retries;
 128         ++retry_threads_running;
 129         thread(&ALSAPool::probe_device_retry_thread_func, this, card_index, dev_index).detach();
 130 }
 131
 132 void ALSAPool::probe_device_retry_thread_func(unsigned card_index, unsigned dev_index)
 133 {
 134         char address[256];
 135         snprintf(address, sizeof(address), "hw:%d,%d", card_index, dev_index);
 136
 137         for ( ;; ) {  // Termination condition within the loop.
 138                 sleep(1);
 139
 140                 // See if there are any retries left.
 141                 lock_guard<mutex> lock(add_device_mutex);
 142                 if (should_quit ||
 143                     !add_device_tries_left.count(address) ||
 144                     add_device_tries_left[address] == 0) {
 145                         add_device_tries_left.erase(address);
 146                         fprintf(stderr, "Giving up probe of %s.\n", address);
 147                         break;
 148                 }
 149
 150                 // Seemingly there were. Give it a try (we still hold the mutex).
 151                 ProbeResult result = probe_device_once(card_index, dev_index);
 152                 if (result == ProbeResult::SUCCESS) {
 153                         add_device_tries_left.erase(address);
 154                         fprintf(stderr, "Probe of %s succeeded.\n", address);
 155                         break;
 156                 } else if (result == ProbeResult::FAILURE || --add_device_tries_left[address] == 0) {
 157                         add_device_tries_left.erase(address);
 158                         fprintf(stderr, "Giving up probe of %s.\n", address);
 159                         break;
 160                 }
 161
 162                 // Failed again.
 163                 assert(result == ProbeResult::DEFER);
 164                 fprintf(stderr, "Trying %s again in one second (%d tries left)...\n",
 165                         address, add_device_tries_left[address]);
 166         }
 167
 168         --retry_threads_running;
 169 }
 170
 171 ALSAPool::ProbeResult ALSAPool::probe_device_once(unsigned card_index, unsigned dev_index)
 172 {
 173         char address[256];
 174         snprintf(address, sizeof(address), "hw:%d", card_index);
 175         snd_ctl_t *ctl;
 176         int err = snd_ctl_open(&ctl, address, 0);
 177         if (err < 0) {
 178                 printf("%s: %s\n", address, snd_strerror(err));
 179                 return ALSAPool::ProbeResult::DEFER;
 180         }
 181         unique_ptr<snd_ctl_t, decltype(snd_ctl_close)*> ctl_closer(ctl, snd_ctl_close);
 182
 183         snd_pcm_info_t *pcm_info;
 184         snd_pcm_info_alloca(&pcm_info);
 185         snd_pcm_info_set_device(pcm_info, dev_index);
 186         snd_pcm_info_set_subdevice(pcm_info, 0);
 187         snd_pcm_info_set_stream(pcm_info, SND_PCM_STREAM_CAPTURE);
 188         if (snd_ctl_pcm_info(ctl, pcm_info) < 0) {
 189                 // Not available for capture.
 190                 printf("%s: Not available for capture.\n", address);
 191                 return ALSAPool::ProbeResult::DEFER;
 192         }
 193
 194         snprintf(address, sizeof(address), "hw:%d,%d", card_index, dev_index);
 195
 196         unsigned num_channels = 0;
 197
 198         // Find all channel maps for this device, and pick out the one
 199         // with the most channels.
 200         snd_pcm_chmap_query_t **cmaps = snd_pcm_query_chmaps_from_hw(card_index, dev_index, 0, SND_PCM_STREAM_CAPTURE);
 201         if (cmaps != nullptr) {
 202                 for (snd_pcm_chmap_query_t **ptr = cmaps; *ptr; ++ptr) {
 203                         num_channels = max(num_channels, (*ptr)->map.channels);
 204                 }
 205                 snd_pcm_free_chmaps(cmaps);
 206         }
 207         if (num_channels == 0) {
 208                 // Device had no channel maps. We need to open it to query.
 209                 // TODO: Do this asynchronously.
 210                 snd_pcm_t *pcm_handle;
 211                 int err = snd_pcm_open(&pcm_handle, address, SND_PCM_STREAM_CAPTURE, 0);
 212                 if (err < 0) {
 213                         printf("%s: %s\n", address, snd_strerror(err));
 214                         return ALSAPool::ProbeResult::DEFER;
 215                 }
 216                 snd_pcm_hw_params_t *hw_params;
 217                 snd_pcm_hw_params_alloca(&hw_params);
 218                 unsigned sample_rate;
 219                 if (!ALSAInput::set_base_params(address, pcm_handle, hw_params, &sample_rate)) {
 220                         snd_pcm_close(pcm_handle);
 221                         return ALSAPool::ProbeResult::DEFER;
 222                 }
 223                 err = snd_pcm_hw_params_get_channels_max(hw_params, &num_channels);
 224                 if (err < 0) {
 225                         fprintf(stderr, "[%s] snd_pcm_hw_params_get_channels_max(): %s\n",
 226                                 address, snd_strerror(err));
 227                         snd_pcm_close(pcm_handle);
 228                         return ALSAPool::ProbeResult::DEFER;
 229                 }
 230                 snd_pcm_close(pcm_handle);
 231         }
 232
 233         if (num_channels == 0) {
 234                 printf("%s: No channel maps with channels\n", address);
 235                 return ALSAPool::ProbeResult::FAILURE;
 236         }
 237
 238         snd_ctl_card_info_t *card_info;
 239         snd_ctl_card_info_alloca(&card_info);
 240         snd_ctl_card_info(ctl, card_info);
 241
 242         string name = snd_ctl_card_info_get_name(card_info);
 243         string info = snd_pcm_info_get_name(pcm_info);
 244
 245         unsigned internal_dev_index;
 246         string display_name;
 247         {
 248                 lock_guard<mutex> lock(mu);
 249                 internal_dev_index = find_free_device_index(name, info, num_channels, address);
 250                 devices[internal_dev_index].address = address;
 251                 devices[internal_dev_index].name = name;
 252                 devices[internal_dev_index].info = info;
 253                 devices[internal_dev_index].num_channels = num_channels;
 254                 // Note: Purposefully does not overwrite held.
 255
 256                 display_name = devices[internal_dev_index].display_name();
 257         }
 258
 259         fprintf(stderr, "%s: Probed successfully.\n", address);
 260
 261         reset_device(internal_dev_index);  // Restarts it if it is held (ie., we just replaced a dead card).
 262
 263         DeviceSpec spec{InputSourceType::ALSA_INPUT, internal_dev_index};
 264         global_audio_mixer->set_display_name(spec, display_name);
 265         global_audio_mixer->trigger_state_changed_callback();
 266
 267         return ALSAPool::ProbeResult::SUCCESS;
 268 }
 269
 270 void ALSAPool::unplug_device(unsigned card_index, unsigned dev_index)
 271 {
 272         char address[256];
 273         snprintf(address, sizeof(address), "hw:%d,%d", card_index, dev_index);
 274         for (unsigned i = 0; i < devices.size(); ++i) {
 275                 if (devices[i].state != Device::State::EMPTY &&
 276                     devices[i].state != Device::State::DEAD &&
 277                     devices[i].address == address) {
 278                         free_card(i);
 279                 }
 280         }
 281 }
 282
 283 void ALSAPool::init()
 284 {
 285         inotify_thread = thread(&ALSAPool::inotify_thread_func, this);
 286         enumerate_devices();
 287 }
 288
 289 void ALSAPool::inotify_thread_func()
 290 {
 291         int inotify_fd = inotify_init();
 292         if (inotify_fd == -1) {
 293                 perror("inotify_init()");
 294                 fprintf(stderr, "No hotplug of ALSA devices available.\n");
 295                 return;
 296         }
 297
 298         int watch_fd = inotify_add_watch(inotify_fd, "/dev/snd", IN_MOVE | IN_CREATE | IN_DELETE);
 299         if (watch_fd == -1) {
 300                 perror("inotify_add_watch()");
 301                 fprintf(stderr, "No hotplug of ALSA devices available.\n");
 302                 close(inotify_fd);
 303                 return;
 304         }
 305
 306         int size = sizeof(inotify_event) + NAME_MAX + 1;
 307         unique_ptr<char[]> buf(new char[size]);
 308         while (!should_quit) {
 309                 pollfd fds[2];
 310                 fds[0].fd = inotify_fd;
 311                 fds[0].events = POLLIN;
 312                 fds[0].revents = 0;
 313                 fds[1].fd = should_quit_fd;
 314                 fds[1].events = POLLIN;
 315                 fds[1].revents = 0;
 316
 317                 int ret = poll(fds, 2, -1);
 318                 if (ret == -1) {
 319                         if (errno == EINTR) {
 320                                 continue;
 321                         } else {
 322                                 perror("poll(inotify_fd)");
 323                                 return;
 324                         }
 325                 }
 326                 if (ret == 0) {
 327                         continue;
 328                 }
 329
 330                 if (fds[1].revents) break;  // should_quit_fd asserted.
 331
 332                 ret = read(inotify_fd, buf.get(), size);
 333                 if (ret == -1) {
 334                         if (errno == EINTR) {
 335                                 continue;
 336                         } else {
 337                                 perror("read(inotify_fd)");
 338                                 close(watch_fd);
 339                                 close(inotify_fd);
 340                                 return;
 341                         }
 342                 }
 343                 if (ret < int(sizeof(inotify_event))) {
 344                         fprintf(stderr, "inotify read unexpectedly returned %d, giving up hotplug of ALSA devices.\n",
 345                                 int(ret));
 346                         close(watch_fd);
 347                         close(inotify_fd);
 348                         return;
 349                 }
 350
 351                 for (int i = 0; i < ret; ) {
 352                         const inotify_event *event = reinterpret_cast<const inotify_event *>(&buf[i]);
 353                         i += sizeof(inotify_event) + event->len;
 354
 355                         if (event->mask & IN_Q_OVERFLOW) {
 356                                 fprintf(stderr, "WARNING: inotify overflowed, may lose ALSA hotplug events.\n");
 357                                 continue;
 358                         }
 359                         unsigned card, device;
 360                         char type;
 361                         if (sscanf(event->name, "pcmC%uD%u%c", &card, &device, &type) == 3 && type == 'c') {
 362                                 if (event->mask & (IN_MOVED_FROM | IN_DELETE)) {
 363                                         printf("Deleted capture device: Card %u, device %u\n", card, device);
 364                                         unplug_device(card, device);
 365                                 }
 366                                 if (event->mask & (IN_MOVED_TO | IN_CREATE)) {
 367                                         printf("Adding capture device: Card %u, device %u\n", card, device);
 368                                         probe_device_with_retry(card, device);
 369                                 }
 370                         }
 371                 }
 372         }
 373         close(watch_fd);
 374         close(inotify_fd);
 375         close(should_quit_fd);
 376 }
 377
 378 void ALSAPool::reset_device(unsigned index)
 379 {
 380         lock_guard<mutex> lock(mu);
 381         Device *device = &devices[index];
 382         if (inputs[index] != nullptr) {
 383                 inputs[index]->stop_capture_thread();
 384         }
 385         if (!device->held) {
 386                 inputs[index].reset();
 387         } else {
 388                 // TODO: Put on a background thread instead of locking?
 389                 auto callback = bind(&AudioMixer::add_audio, global_audio_mixer, DeviceSpec{InputSourceType::ALSA_INPUT, index}, _1, _2, _3, _4);
 390                 inputs[index].reset(new ALSAInput(device->address.c_str(), OUTPUT_FREQUENCY, device->num_channels, callback, this, index));
 391                 inputs[index]->start_capture_thread();
 392         }
 393         device->input = inputs[index].get();
 394 }
 395
 396 unsigned ALSAPool::get_capture_frequency(unsigned index)
 397 {
 398         lock_guard<mutex> lock(mu);
 399         assert(devices[index].held);
 400         if (devices[index].input)
 401                 return devices[index].input->get_sample_rate();
 402         else
 403                 return OUTPUT_FREQUENCY;
 404 }
 405
 406 ALSAPool::Device::State ALSAPool::get_card_state(unsigned index)
 407 {
 408         lock_guard<mutex> lock(mu);
 409         assert(devices[index].held);
 410         return devices[index].state;
 411 }
 412
 413 void ALSAPool::set_card_state(unsigned index, ALSAPool::Device::State state)
 414 {
 415         {
 416                 lock_guard<mutex> lock(mu);
 417                 devices[index].state = state;
 418         }
 419
 420         DeviceSpec spec{InputSourceType::ALSA_INPUT, index};
 421         bool silence = (state != ALSAPool::Device::State::RUNNING);
 422         while (!global_audio_mixer->silence_card(spec, silence))
 423                 ;
 424         global_audio_mixer->trigger_state_changed_callback();
 425 }
 426
 427 unsigned ALSAPool::find_free_device_index(const string &name, const string &info, unsigned num_channels, const string &address)
 428 {
 429         // First try to find an exact match on a dead card.
 430         for (unsigned i = 0; i < devices.size(); ++i) {
 431                 if (devices[i].state == Device::State::DEAD &&
 432                     devices[i].address == address &&
 433                     devices[i].name == name &&
 434                     devices[i].info == info &&
 435                     devices[i].num_channels == num_channels) {
 436                         devices[i].state = Device::State::READY;
 437                         return i;
 438                 }
 439         }
 440
 441         // Then try to find a match on everything but the address
 442         // (probably that devices were plugged back in a different order).
 443         // If we have two cards that are equal, this might get them mixed up,
 444         // but we don't have anything better.
 445         for (unsigned i = 0; i < devices.size(); ++i) {
 446                 if (devices[i].state == Device::State::DEAD &&
 447                     devices[i].name == name &&
 448                     devices[i].info == info &&
 449                     devices[i].num_channels == num_channels) {
 450                         devices[i].state = Device::State::READY;
 451                         return i;
 452                 }
 453         }
 454
 455         // OK, so we didn't find a match; see if there are any empty slots.
 456         for (unsigned i = 0; i < devices.size(); ++i) {
 457                 if (devices[i].state == Device::State::EMPTY) {
 458                         devices[i].state = Device::State::READY;
 459                         devices[i].held = false;
 460                         return i;
 461                 }
 462         }
 463
 464         // Failing that, we just insert the new device at the end.
 465         Device new_dev;
 466         new_dev.state = Device::State::READY;
 467         new_dev.held = false;
 468         devices.push_back(new_dev);
 469         inputs.emplace_back(nullptr);
 470         return devices.size() - 1;
 471 }
 472
 473 unsigned ALSAPool::create_dead_card(const string &name, const string &info, unsigned num_channels)
 474 {
 475         lock_guard<mutex> lock(mu);
 476
 477         // See if there are any empty slots. If not, insert one at the end.
 478         vector<Device>::iterator free_device =
 479                 find_if(devices.begin(), devices.end(),
 480                         [](const Device &device) { return device.state == Device::State::EMPTY; });
 481         if (free_device == devices.end()) {
 482                 devices.push_back(Device());
 483                 inputs.emplace_back(nullptr);
 484                 free_device = devices.end() - 1;
 485         }
 486
 487         free_device->state = Device::State::DEAD;
 488         free_device->name = name;
 489         free_device->info = info;
 490         free_device->num_channels = num_channels;
 491         free_device->held = true;
 492
 493         return distance(devices.begin(), free_device);
 494 }
 495
 496 void ALSAPool::serialize_device(unsigned index, DeviceSpecProto *serialized)
 497 {
 498         lock_guard<mutex> lock(mu);
 499         assert(index < devices.size());
 500         assert(devices[index].held);
 501         serialized->set_type(DeviceSpecProto::ALSA_INPUT);
 502         serialized->set_index(index);
 503         serialized->set_display_name(devices[index].display_name());
 504         serialized->set_alsa_name(devices[index].name);
 505         serialized->set_alsa_info(devices[index].info);
 506         serialized->set_num_channels(devices[index].num_channels);
 507         serialized->set_address(devices[index].address);
 508 }
 509
 510 void ALSAPool::free_card(unsigned index)
 511 {
 512         DeviceSpec spec{InputSourceType::ALSA_INPUT, index};
 513         while (!global_audio_mixer->silence_card(spec, true))
 514                 ;
 515
 516         {
 517                 lock_guard<mutex> lock(mu);
 518                 if (devices[index].held) {
 519                         devices[index].state = Device::State::DEAD;
 520                 } else {
 521                         devices[index].state = Device::State::EMPTY;
 522                         inputs[index].reset();
 523                 }
 524                 while (!devices.empty() && devices.back().state == Device::State::EMPTY) {
 525                         devices.pop_back();
 526                         inputs.pop_back();
 527                 }
 528         }
 529
 530         global_audio_mixer->trigger_state_changed_callback();
 531 }