git.sesse.net Git - nageru/blob - nageru/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 <pthread.h>
   8 #include <poll.h>
   9 #include <stdint.h>
  10 #include <stdio.h>
  11 #include <sys/eventfd.h>
  12 #include <sys/inotify.h>
  13 #include <unistd.h>
  14 #include <algorithm>
  15 #include <chrono>
  16 #include <functional>
  17 #include <iterator>
  18 #include <memory>
  19 #include <ratio>
  20
  21 #include "alsa_input.h"
  22 #include "audio_mixer.h"
  23 #include "defs.h"
  24 #include "input_mapping.h"
  25 #include "state.pb.h"
  26
  27 using namespace std;
  28 using namespace std::placeholders;
  29
  30 ALSAPool::ALSAPool()
  31 {
  32         should_quit_fd = eventfd(/*initval=*/0, /*flags=*/0);
  33         assert(should_quit_fd != -1);
  34 }
  35
  36 ALSAPool::~ALSAPool()
  37 {
  38         for (Device &device : devices) {
  39                 if (device.input != nullptr) {
  40                         device.input->stop_capture_thread();
  41                 }
  42         }
  43         should_quit = true;
  44         const uint64_t one = 1;
  45         if (write(should_quit_fd, &one, sizeof(one)) != sizeof(one)) {
  46                 perror("write(should_quit_fd)");
  47                 abort();
  48         }
  49         inotify_thread.join();
  50
  51         while (retry_threads_running > 0) {
  52                 this_thread::sleep_for(std::chrono::milliseconds(100));
  53         }
  54 }
  55
  56 std::vector<ALSAPool::Device> ALSAPool::get_devices(bool hold_devices)
  57 {
  58         lock_guard<mutex> lock(mu);
  59         if (hold_devices) {
  60                 for (Device &device : devices) {
  61                         device.held = true;
  62                 }
  63         }
  64         return devices;
  65 }
  66
  67 void ALSAPool::hold_device(unsigned index)
  68 {
  69         lock_guard<mutex> lock(mu);
  70         assert(index < devices.size());
  71         devices[index].held = true;
  72 }
  73
  74 void ALSAPool::release_device(unsigned index)
  75 {
  76         lock_guard<mutex> lock(mu);
  77         if (index < devices.size()) {
  78                 devices[index].held = false;
  79         }
  80 }
  81
  82 void ALSAPool::enumerate_devices()
  83 {
  84         // Enumerate all cards.
  85         for (int card_index = -1; snd_card_next(&card_index) == 0 && card_index >= 0; ) {
  86                 char address[256];
  87                 snprintf(address, sizeof(address), "hw:%d", card_index);
  88
  89                 snd_ctl_t *ctl;
  90                 int err = snd_ctl_open(&ctl, address, 0);
  91                 if (err < 0) {
  92                         printf("%s: %s\n", address, snd_strerror(err));
  93                         continue;
  94                 }
  95                 unique_ptr<snd_ctl_t, decltype(snd_ctl_close)*> ctl_closer(ctl, snd_ctl_close);
  96
  97                 // Enumerate all devices on this card.
  98                 for (int dev_index = -1; snd_ctl_pcm_next_device(ctl, &dev_index) == 0 && dev_index >= 0; ) {
  99                         probe_device_with_retry(card_index, dev_index);
 100                 }
 101         }
 102 }
 103
 104 void ALSAPool::probe_device_with_retry(unsigned card_index, unsigned dev_index)
 105 {
 106         char address[256];
 107         snprintf(address, sizeof(address), "hw:%d,%d", card_index, dev_index);
 108
 109         lock_guard<mutex> lock(add_device_mutex);
 110         if (add_device_tries_left.count(address)) {
 111                 // Some thread is already busy retrying this,
 112                 // so just reset its count.
 113                 add_device_tries_left[address] = num_retries;
 114                 return;
 115         }
 116
 117         // Try (while still holding the lock) to add the device synchronously.
 118         ProbeResult result = probe_device_once(card_index, dev_index);
 119         if (result == ProbeResult::SUCCESS) {
 120                 return;
 121         } else if (result == ProbeResult::FAILURE) {
 122                 return;
 123         }
 124         assert(result == ProbeResult::DEFER);
 125
 126         // Add failed for whatever reason (probably just that the device
 127         // isn't up yet. Set up a count so that nobody else starts a thread,
 128         // then start it ourselves.
 129         fprintf(stderr, "Trying %s again in one second...\n", address);
 130         add_device_tries_left[address] = num_retries;
 131         ++retry_threads_running;
 132         thread(&ALSAPool::probe_device_retry_thread_func, this, card_index, dev_index).detach();
 133 }
 134
 135 void ALSAPool::probe_device_retry_thread_func(unsigned card_index, unsigned dev_index)
 136 {
 137         char address[256];
 138         snprintf(address, sizeof(address), "hw:%d,%d", card_index, dev_index);
 139
 140         char thread_name[16];
 141         snprintf(thread_name, sizeof(thread_name), "Reprobe_hw:%d,%d", card_index, dev_index);
 142         pthread_setname_np(pthread_self(), thread_name);
 143
 144         for ( ;; ) {  // Termination condition within the loop.
 145                 sleep(1);
 146
 147                 // See if there are any retries left.
 148                 lock_guard<mutex> lock(add_device_mutex);
 149                 if (should_quit ||
 150                     !add_device_tries_left.count(address) ||
 151                     add_device_tries_left[address] == 0) {
 152                         add_device_tries_left.erase(address);
 153                         fprintf(stderr, "Giving up probe of %s.\n", address);
 154                         break;
 155                 }
 156
 157                 // Seemingly there were. Give it a try (we still hold the mutex).
 158                 ProbeResult result = probe_device_once(card_index, dev_index);
 159                 if (result == ProbeResult::SUCCESS) {
 160                         add_device_tries_left.erase(address);
 161                         fprintf(stderr, "Probe of %s succeeded.\n", address);
 162                         break;
 163                 } else if (result == ProbeResult::FAILURE || --add_device_tries_left[address] == 0) {
 164                         add_device_tries_left.erase(address);
 165                         fprintf(stderr, "Giving up probe of %s.\n", address);
 166                         break;
 167                 }
 168
 169                 // Failed again.
 170                 assert(result == ProbeResult::DEFER);
 171                 fprintf(stderr, "Trying %s again in one second (%d tries left)...\n",
 172                         address, add_device_tries_left[address]);
 173         }
 174
 175         --retry_threads_running;
 176 }
 177
 178 ALSAPool::ProbeResult ALSAPool::probe_device_once(unsigned card_index, unsigned dev_index)
 179 {
 180         char address[256];
 181         snprintf(address, sizeof(address), "hw:%d", card_index);
 182         snd_ctl_t *ctl;
 183         int err = snd_ctl_open(&ctl, address, 0);
 184         if (err < 0) {
 185                 printf("%s: %s\n", address, snd_strerror(err));
 186                 return ALSAPool::ProbeResult::DEFER;
 187         }
 188         unique_ptr<snd_ctl_t, decltype(snd_ctl_close)*> ctl_closer(ctl, snd_ctl_close);
 189
 190         snprintf(address, sizeof(address), "hw:%d,%d", card_index, dev_index);
 191
 192         snd_pcm_info_t *pcm_info;
 193         snd_pcm_info_alloca(&pcm_info);
 194         snd_pcm_info_set_device(pcm_info, dev_index);
 195         snd_pcm_info_set_subdevice(pcm_info, 0);
 196         snd_pcm_info_set_stream(pcm_info, SND_PCM_STREAM_CAPTURE);
 197         err = snd_ctl_pcm_info(ctl, pcm_info);
 198         if (err == -ENOENT) {
 199                 // Not a capture card.
 200                 return ALSAPool::ProbeResult::FAILURE;
 201         }
 202         if (err < 0) {
 203                 // Not available for capture.
 204                 printf("%s: Not available for capture.\n", address);
 205                 return ALSAPool::ProbeResult::DEFER;
 206         }
 207
 208         unsigned num_channels = 0;
 209
 210         // Find all channel maps for this device, and pick out the one
 211         // with the most channels.
 212         snd_pcm_chmap_query_t **cmaps = snd_pcm_query_chmaps_from_hw(card_index, dev_index, 0, SND_PCM_STREAM_CAPTURE);
 213         if (cmaps != nullptr) {
 214                 for (snd_pcm_chmap_query_t **ptr = cmaps; *ptr; ++ptr) {
 215                         num_channels = max(num_channels, (*ptr)->map.channels);
 216                 }
 217                 snd_pcm_free_chmaps(cmaps);
 218         }
 219         if (num_channels == 0) {
 220                 // Device had no channel maps. We need to open it to query.
 221                 // TODO: Do this asynchronously.
 222                 snd_pcm_t *pcm_handle;
 223                 int err = snd_pcm_open(&pcm_handle, address, SND_PCM_STREAM_CAPTURE, 0);
 224                 if (err < 0) {
 225                         printf("%s: %s\n", address, snd_strerror(err));
 226                         return ALSAPool::ProbeResult::DEFER;
 227                 }
 228                 snd_pcm_hw_params_t *hw_params;
 229                 snd_pcm_hw_params_alloca(&hw_params);
 230                 unsigned sample_rate;
 231                 if (!ALSAInput::set_base_params(address, pcm_handle, hw_params, &sample_rate)) {
 232                         snd_pcm_close(pcm_handle);
 233                         return ALSAPool::ProbeResult::DEFER;
 234                 }
 235                 err = snd_pcm_hw_params_get_channels_max(hw_params, &num_channels);
 236                 if (err < 0) {
 237                         fprintf(stderr, "[%s] snd_pcm_hw_params_get_channels_max(): %s\n",
 238                                 address, snd_strerror(err));
 239                         snd_pcm_close(pcm_handle);
 240                         return ALSAPool::ProbeResult::DEFER;
 241                 }
 242                 snd_pcm_close(pcm_handle);
 243         }
 244
 245         if (num_channels == 0) {
 246                 printf("%s: No channel maps with channels\n", address);
 247                 return ALSAPool::ProbeResult::FAILURE;
 248         }
 249
 250         snd_ctl_card_info_t *card_info;
 251         snd_ctl_card_info_alloca(&card_info);
 252         snd_ctl_card_info(ctl, card_info);
 253
 254         string name = snd_ctl_card_info_get_name(card_info);
 255         string info = snd_pcm_info_get_name(pcm_info);
 256
 257         unsigned internal_dev_index;
 258         string display_name;
 259         {
 260                 lock_guard<mutex> lock(mu);
 261                 internal_dev_index = find_free_device_index(name, info, num_channels, address);
 262                 devices[internal_dev_index].address = address;
 263                 devices[internal_dev_index].name = name;
 264                 devices[internal_dev_index].info = info;
 265                 devices[internal_dev_index].num_channels = num_channels;
 266                 // Note: Purposefully does not overwrite held.
 267
 268                 display_name = devices[internal_dev_index].display_name();
 269         }
 270
 271         fprintf(stderr, "%s: Probed successfully.\n", address);
 272
 273         reset_device(internal_dev_index);  // Restarts it if it is held (ie., we just replaced a dead card).
 274
 275         DeviceSpec spec{InputSourceType::ALSA_INPUT, internal_dev_index};
 276         global_audio_mixer->set_display_name(spec, display_name);
 277         global_audio_mixer->trigger_state_changed_callback();
 278
 279         return ALSAPool::ProbeResult::SUCCESS;
 280 }
 281
 282 void ALSAPool::unplug_device(unsigned card_index, unsigned dev_index)
 283 {
 284         char address[256];
 285         snprintf(address, sizeof(address), "hw:%d,%d", card_index, dev_index);
 286         for (unsigned i = 0; i < devices.size(); ++i) {
 287                 if (devices[i].state != Device::State::EMPTY &&
 288                     devices[i].state != Device::State::DEAD &&
 289                     devices[i].address == address) {
 290                         free_card(i);
 291                 }
 292         }
 293 }
 294
 295 void ALSAPool::init()
 296 {
 297         inotify_thread = thread(&ALSAPool::inotify_thread_func, this);
 298         enumerate_devices();
 299 }
 300
 301 void ALSAPool::inotify_thread_func()
 302 {
 303         pthread_setname_np(pthread_self(), "ALSA_Hotplug");
 304
 305         int inotify_fd = inotify_init();
 306         if (inotify_fd == -1) {
 307                 perror("inotify_init()");
 308                 fprintf(stderr, "No hotplug of ALSA devices available.\n");
 309                 return;
 310         }
 311
 312         int watch_fd = inotify_add_watch(inotify_fd, "/dev/snd", IN_MOVE | IN_CREATE | IN_DELETE);
 313         if (watch_fd == -1) {
 314                 perror("inotify_add_watch()");
 315                 fprintf(stderr, "No hotplug of ALSA devices available.\n");
 316                 close(inotify_fd);
 317                 return;
 318         }
 319
 320         int size = sizeof(inotify_event) + NAME_MAX + 1;
 321         unique_ptr<char[]> buf(new char[size]);
 322         while (!should_quit) {
 323                 pollfd fds[2];
 324                 fds[0].fd = inotify_fd;
 325                 fds[0].events = POLLIN;
 326                 fds[0].revents = 0;
 327                 fds[1].fd = should_quit_fd;
 328                 fds[1].events = POLLIN;
 329                 fds[1].revents = 0;
 330
 331                 int ret = poll(fds, 2, -1);
 332                 if (ret == -1) {
 333                         if (errno == EINTR) {
 334                                 continue;
 335                         } else {
 336                                 perror("poll(inotify_fd)");
 337                                 return;
 338                         }
 339                 }
 340                 if (ret == 0) {
 341                         continue;
 342                 }
 343
 344                 if (fds[1].revents) break;  // should_quit_fd asserted.
 345
 346                 ret = read(inotify_fd, buf.get(), size);
 347                 if (ret == -1) {
 348                         if (errno == EINTR) {
 349                                 continue;
 350                         } else {
 351                                 perror("read(inotify_fd)");
 352                                 close(watch_fd);
 353                                 close(inotify_fd);
 354                                 return;
 355                         }
 356                 }
 357                 if (ret < int(sizeof(inotify_event))) {
 358                         fprintf(stderr, "inotify read unexpectedly returned %d, giving up hotplug of ALSA devices.\n",
 359                                 int(ret));
 360                         close(watch_fd);
 361                         close(inotify_fd);
 362                         return;
 363                 }
 364
 365                 for (int i = 0; i < ret; ) {
 366                         const inotify_event *event = reinterpret_cast<const inotify_event *>(&buf[i]);
 367                         i += sizeof(inotify_event) + event->len;
 368
 369                         if (event->mask & IN_Q_OVERFLOW) {
 370                                 fprintf(stderr, "WARNING: inotify overflowed, may lose ALSA hotplug events.\n");
 371                                 continue;
 372                         }
 373                         unsigned card, device;
 374                         char type;
 375                         if (sscanf(event->name, "pcmC%uD%u%c", &card, &device, &type) == 3 && type == 'c') {
 376                                 if (event->mask & (IN_MOVED_FROM | IN_DELETE)) {
 377                                         printf("Deleted capture device: Card %u, device %u\n", card, device);
 378                                         unplug_device(card, device);
 379                                 }
 380                                 if (event->mask & (IN_MOVED_TO | IN_CREATE)) {
 381                                         printf("Adding capture device: Card %u, device %u\n", card, device);
 382                                         probe_device_with_retry(card, device);
 383                                 }
 384                         }
 385                 }
 386         }
 387         close(watch_fd);
 388         close(inotify_fd);
 389         close(should_quit_fd);
 390 }
 391
 392 void ALSAPool::reset_device(unsigned index)
 393 {
 394         lock_guard<mutex> lock(mu);
 395         Device *device = &devices[index];
 396         if (device->state == Device::State::DEAD) {
 397                 // Not running, and should not be started.
 398                 return;
 399         }
 400         if (inputs[index] != nullptr) {
 401                 inputs[index]->stop_capture_thread();
 402         }
 403         if (!device->held) {
 404                 inputs[index].reset();
 405         } else {
 406                 // TODO: Put on a background thread instead of locking?
 407                 auto callback = bind(&AudioMixer::add_audio, global_audio_mixer, DeviceSpec{InputSourceType::ALSA_INPUT, index}, _1, _2, _3, _4);
 408                 inputs[index].reset(new ALSAInput(device->address.c_str(), OUTPUT_FREQUENCY, device->num_channels, callback, this, index));
 409                 inputs[index]->start_capture_thread();
 410         }
 411         device->input = inputs[index].get();
 412 }
 413
 414 unsigned ALSAPool::get_capture_frequency(unsigned index)
 415 {
 416         lock_guard<mutex> lock(mu);
 417         assert(devices[index].held);
 418         if (devices[index].input)
 419                 return devices[index].input->get_sample_rate();
 420         else
 421                 return OUTPUT_FREQUENCY;
 422 }
 423
 424 ALSAPool::Device::State ALSAPool::get_card_state(unsigned index)
 425 {
 426         lock_guard<mutex> lock(mu);
 427         assert(devices[index].held);
 428         return devices[index].state;
 429 }
 430
 431 void ALSAPool::set_card_state(unsigned index, ALSAPool::Device::State state)
 432 {
 433         {
 434                 lock_guard<mutex> lock(mu);
 435                 devices[index].state = state;
 436         }
 437
 438         DeviceSpec spec{InputSourceType::ALSA_INPUT, index};
 439         bool silence = (state != ALSAPool::Device::State::RUNNING);
 440         while (!global_audio_mixer->silence_card(spec, silence))
 441                 ;
 442         global_audio_mixer->trigger_state_changed_callback();
 443 }
 444
 445 unsigned ALSAPool::find_free_device_index(const string &name, const string &info, unsigned num_channels, const string &address)
 446 {
 447         // First try to find an exact match on a dead card.
 448         for (unsigned i = 0; i < devices.size(); ++i) {
 449                 if (devices[i].state == Device::State::DEAD &&
 450                     devices[i].address == address &&
 451                     devices[i].name == name &&
 452                     devices[i].info == info &&
 453                     devices[i].num_channels == num_channels) {
 454                         devices[i].state = Device::State::READY;
 455                         return i;
 456                 }
 457         }
 458
 459         // Then try to find a match on everything but the address
 460         // (probably that devices were plugged back in a different order).
 461         // If we have two cards that are equal, this might get them mixed up,
 462         // but we don't have anything better.
 463         for (unsigned i = 0; i < devices.size(); ++i) {
 464                 if (devices[i].state == Device::State::DEAD &&
 465                     devices[i].name == name &&
 466                     devices[i].info == info &&
 467                     devices[i].num_channels == num_channels) {
 468                         devices[i].state = Device::State::READY;
 469                         return i;
 470                 }
 471         }
 472
 473         // OK, so we didn't find a match; see if there are any empty slots.
 474         for (unsigned i = 0; i < devices.size(); ++i) {
 475                 if (devices[i].state == Device::State::EMPTY) {
 476                         devices[i].state = Device::State::READY;
 477                         devices[i].held = false;
 478                         return i;
 479                 }
 480         }
 481
 482         // Failing that, we just insert the new device at the end.
 483         Device new_dev;
 484         new_dev.state = Device::State::READY;
 485         new_dev.held = false;
 486         devices.push_back(new_dev);
 487         inputs.emplace_back(nullptr);
 488         return devices.size() - 1;
 489 }
 490
 491 unsigned ALSAPool::create_dead_card(const string &name, const string &info, unsigned num_channels)
 492 {
 493         lock_guard<mutex> lock(mu);
 494
 495         // See if there are any empty slots. If not, insert one at the end.
 496         vector<Device>::iterator free_device =
 497                 find_if(devices.begin(), devices.end(),
 498                         [](const Device &device) { return device.state == Device::State::EMPTY; });
 499         if (free_device == devices.end()) {
 500                 devices.push_back(Device());
 501                 inputs.emplace_back(nullptr);
 502                 free_device = devices.end() - 1;
 503         }
 504
 505         free_device->state = Device::State::DEAD;
 506         free_device->name = name;
 507         free_device->info = info;
 508         free_device->num_channels = num_channels;
 509         free_device->held = true;
 510
 511         return distance(devices.begin(), free_device);
 512 }
 513
 514 void ALSAPool::serialize_device(unsigned index, DeviceSpecProto *serialized)
 515 {
 516         lock_guard<mutex> lock(mu);
 517         assert(index < devices.size());
 518         assert(devices[index].held);
 519         serialized->set_type(DeviceSpecProto::ALSA_INPUT);
 520         serialized->set_index(index);
 521         serialized->set_display_name(devices[index].display_name());
 522         serialized->set_alsa_name(devices[index].name);
 523         serialized->set_alsa_info(devices[index].info);
 524         serialized->set_num_channels(devices[index].num_channels);
 525         serialized->set_address(devices[index].address);
 526 }
 527
 528 void ALSAPool::free_card(unsigned index)
 529 {
 530         DeviceSpec spec{InputSourceType::ALSA_INPUT, index};
 531         while (!global_audio_mixer->silence_card(spec, true))
 532                 ;
 533
 534         {
 535                 lock_guard<mutex> lock(mu);
 536                 if (devices[index].held) {
 537                         devices[index].state = Device::State::DEAD;
 538                 } else {
 539                         devices[index].state = Device::State::EMPTY;
 540                         inputs[index].reset();
 541                 }
 542                 while (!devices.empty() && devices.back().state == Device::State::EMPTY) {
 543                         devices.pop_back();
 544                         inputs.pop_back();
 545                 }
 546         }
 547
 548         global_audio_mixer->trigger_state_changed_callback();
 549 }