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 <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                 exit(1);
  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()
  57 {
  58         lock_guard<mutex> lock(mu);
  59         for (Device &device : devices) {
  60                 device.held = true;
  61         }
  62         return devices;
  63 }
  64
  65 void ALSAPool::hold_device(unsigned index)
  66 {
  67         lock_guard<mutex> lock(mu);
  68         assert(index < devices.size());
  69         devices[index].held = true;
  70 }
  71
  72 void ALSAPool::release_device(unsigned index)
  73 {
  74         lock_guard<mutex> lock(mu);
  75         if (index < devices.size()) {
  76                 devices[index].held = false;
  77         }
  78 }
  79
  80 void ALSAPool::enumerate_devices()
  81 {
  82         // Enumerate all cards.
  83         for (int card_index = -1; snd_card_next(&card_index) == 0 && card_index >= 0; ) {
  84                 char address[256];
  85                 snprintf(address, sizeof(address), "hw:%d", card_index);
  86
  87                 snd_ctl_t *ctl;
  88                 int err = snd_ctl_open(&ctl, address, 0);
  89                 if (err < 0) {
  90                         printf("%s: %s\n", address, snd_strerror(err));
  91                         continue;
  92                 }
  93                 unique_ptr<snd_ctl_t, decltype(snd_ctl_close)*> ctl_closer(ctl, snd_ctl_close);
  94
  95                 // Enumerate all devices on this card.
  96                 for (int dev_index = -1; snd_ctl_pcm_next_device(ctl, &dev_index) == 0 && dev_index >= 0; ) {
  97                         probe_device_with_retry(card_index, dev_index);
  98                 }
  99         }
 100 }
 101
 102 void ALSAPool::probe_device_with_retry(unsigned card_index, unsigned dev_index)
 103 {
 104         char address[256];
 105         snprintf(address, sizeof(address), "hw:%d,%d", card_index, dev_index);
 106
 107         lock_guard<mutex> lock(add_device_mutex);
 108         if (add_device_tries_left.count(address)) {
 109                 // Some thread is already busy retrying this,
 110                 // so just reset its count.
 111                 add_device_tries_left[address] = num_retries;
 112                 return;
 113         }
 114
 115         // Try (while still holding the lock) to add the device synchronously.
 116         ProbeResult result = probe_device_once(card_index, dev_index);
 117         if (result == ProbeResult::SUCCESS) {
 118                 return;
 119         } else if (result == ProbeResult::FAILURE) {
 120                 return;
 121         }
 122         assert(result == ProbeResult::DEFER);
 123
 124         // Add failed for whatever reason (probably just that the device
 125         // isn't up yet. Set up a count so that nobody else starts a thread,
 126         // then start it ourselves.
 127         fprintf(stderr, "Trying %s again in one second...\n", address);
 128         add_device_tries_left[address] = num_retries;
 129         ++retry_threads_running;
 130         thread(&ALSAPool::probe_device_retry_thread_func, this, card_index, dev_index).detach();
 131 }
 132
 133 void ALSAPool::probe_device_retry_thread_func(unsigned card_index, unsigned dev_index)
 134 {
 135         char address[256];
 136         snprintf(address, sizeof(address), "hw:%d,%d", card_index, dev_index);
 137
 138         char thread_name[16];
 139         snprintf(thread_name, sizeof(thread_name), "Reprobe_hw:%d,%d", card_index, dev_index);
 140         pthread_setname_np(pthread_self(), thread_name);
 141
 142         for ( ;; ) {  // Termination condition within the loop.
 143                 sleep(1);
 144
 145                 // See if there are any retries left.
 146                 lock_guard<mutex> lock(add_device_mutex);
 147                 if (should_quit ||
 148                     !add_device_tries_left.count(address) ||
 149                     add_device_tries_left[address] == 0) {
 150                         add_device_tries_left.erase(address);
 151                         fprintf(stderr, "Giving up probe of %s.\n", address);
 152                         break;
 153                 }
 154
 155                 // Seemingly there were. Give it a try (we still hold the mutex).
 156                 ProbeResult result = probe_device_once(card_index, dev_index);
 157                 if (result == ProbeResult::SUCCESS) {
 158                         add_device_tries_left.erase(address);
 159                         fprintf(stderr, "Probe of %s succeeded.\n", address);
 160                         break;
 161                 } else if (result == ProbeResult::FAILURE || --add_device_tries_left[address] == 0) {
 162                         add_device_tries_left.erase(address);
 163                         fprintf(stderr, "Giving up probe of %s.\n", address);
 164                         break;
 165                 }
 166
 167                 // Failed again.
 168                 assert(result == ProbeResult::DEFER);
 169                 fprintf(stderr, "Trying %s again in one second (%d tries left)...\n",
 170                         address, add_device_tries_left[address]);
 171         }
 172
 173         --retry_threads_running;
 174 }
 175
 176 ALSAPool::ProbeResult ALSAPool::probe_device_once(unsigned card_index, unsigned dev_index)
 177 {
 178         char address[256];
 179         snprintf(address, sizeof(address), "hw:%d", card_index);
 180         snd_ctl_t *ctl;
 181         int err = snd_ctl_open(&ctl, address, 0);
 182         if (err < 0) {
 183                 printf("%s: %s\n", address, snd_strerror(err));
 184                 return ALSAPool::ProbeResult::DEFER;
 185         }
 186         unique_ptr<snd_ctl_t, decltype(snd_ctl_close)*> ctl_closer(ctl, snd_ctl_close);
 187
 188         snd_pcm_info_t *pcm_info;
 189         snd_pcm_info_alloca(&pcm_info);
 190         snd_pcm_info_set_device(pcm_info, dev_index);
 191         snd_pcm_info_set_subdevice(pcm_info, 0);
 192         snd_pcm_info_set_stream(pcm_info, SND_PCM_STREAM_CAPTURE);
 193         if (snd_ctl_pcm_info(ctl, pcm_info) < 0) {
 194                 // Not available for capture.
 195                 printf("%s: Not available for capture.\n", address);
 196                 return ALSAPool::ProbeResult::DEFER;
 197         }
 198
 199         snprintf(address, sizeof(address), "hw:%d,%d", card_index, dev_index);
 200
 201         unsigned num_channels = 0;
 202
 203         // Find all channel maps for this device, and pick out the one
 204         // with the most channels.
 205         snd_pcm_chmap_query_t **cmaps = snd_pcm_query_chmaps_from_hw(card_index, dev_index, 0, SND_PCM_STREAM_CAPTURE);
 206         if (cmaps != nullptr) {
 207                 for (snd_pcm_chmap_query_t **ptr = cmaps; *ptr; ++ptr) {
 208                         num_channels = max(num_channels, (*ptr)->map.channels);
 209                 }
 210                 snd_pcm_free_chmaps(cmaps);
 211         }
 212         if (num_channels == 0) {
 213                 // Device had no channel maps. We need to open it to query.
 214                 // TODO: Do this asynchronously.
 215                 snd_pcm_t *pcm_handle;
 216                 int err = snd_pcm_open(&pcm_handle, address, SND_PCM_STREAM_CAPTURE, 0);
 217                 if (err < 0) {
 218                         printf("%s: %s\n", address, snd_strerror(err));
 219                         return ALSAPool::ProbeResult::DEFER;
 220                 }
 221                 snd_pcm_hw_params_t *hw_params;
 222                 snd_pcm_hw_params_alloca(&hw_params);
 223                 unsigned sample_rate;
 224                 if (!ALSAInput::set_base_params(address, pcm_handle, hw_params, &sample_rate)) {
 225                         snd_pcm_close(pcm_handle);
 226                         return ALSAPool::ProbeResult::DEFER;
 227                 }
 228                 err = snd_pcm_hw_params_get_channels_max(hw_params, &num_channels);
 229                 if (err < 0) {
 230                         fprintf(stderr, "[%s] snd_pcm_hw_params_get_channels_max(): %s\n",
 231                                 address, snd_strerror(err));
 232                         snd_pcm_close(pcm_handle);
 233                         return ALSAPool::ProbeResult::DEFER;
 234                 }
 235                 snd_pcm_close(pcm_handle);
 236         }
 237
 238         if (num_channels == 0) {
 239                 printf("%s: No channel maps with channels\n", address);
 240                 return ALSAPool::ProbeResult::FAILURE;
 241         }
 242
 243         snd_ctl_card_info_t *card_info;
 244         snd_ctl_card_info_alloca(&card_info);
 245         snd_ctl_card_info(ctl, card_info);
 246
 247         string name = snd_ctl_card_info_get_name(card_info);
 248         string info = snd_pcm_info_get_name(pcm_info);
 249
 250         unsigned internal_dev_index;
 251         string display_name;
 252         {
 253                 lock_guard<mutex> lock(mu);
 254                 internal_dev_index = find_free_device_index(name, info, num_channels, address);
 255                 devices[internal_dev_index].address = address;
 256                 devices[internal_dev_index].name = name;
 257                 devices[internal_dev_index].info = info;
 258                 devices[internal_dev_index].num_channels = num_channels;
 259                 // Note: Purposefully does not overwrite held.
 260
 261                 display_name = devices[internal_dev_index].display_name();
 262         }
 263
 264         fprintf(stderr, "%s: Probed successfully.\n", address);
 265
 266         reset_device(internal_dev_index);  // Restarts it if it is held (ie., we just replaced a dead card).
 267
 268         DeviceSpec spec{InputSourceType::ALSA_INPUT, internal_dev_index};
 269         global_audio_mixer->set_display_name(spec, display_name);
 270         global_audio_mixer->trigger_state_changed_callback();
 271
 272         return ALSAPool::ProbeResult::SUCCESS;
 273 }
 274
 275 void ALSAPool::unplug_device(unsigned card_index, unsigned dev_index)
 276 {
 277         char address[256];
 278         snprintf(address, sizeof(address), "hw:%d,%d", card_index, dev_index);
 279         for (unsigned i = 0; i < devices.size(); ++i) {
 280                 if (devices[i].state != Device::State::EMPTY &&
 281                     devices[i].state != Device::State::DEAD &&
 282                     devices[i].address == address) {
 283                         free_card(i);
 284                 }
 285         }
 286 }
 287
 288 void ALSAPool::init()
 289 {
 290         inotify_thread = thread(&ALSAPool::inotify_thread_func, this);
 291         enumerate_devices();
 292 }
 293
 294 void ALSAPool::inotify_thread_func()
 295 {
 296         pthread_setname_np(pthread_self(), "ALSA_Hotplug");
 297
 298         int inotify_fd = inotify_init();
 299         if (inotify_fd == -1) {
 300                 perror("inotify_init()");
 301                 fprintf(stderr, "No hotplug of ALSA devices available.\n");
 302                 return;
 303         }
 304
 305         int watch_fd = inotify_add_watch(inotify_fd, "/dev/snd", IN_MOVE | IN_CREATE | IN_DELETE);
 306         if (watch_fd == -1) {
 307                 perror("inotify_add_watch()");
 308                 fprintf(stderr, "No hotplug of ALSA devices available.\n");
 309                 close(inotify_fd);
 310                 return;
 311         }
 312
 313         int size = sizeof(inotify_event) + NAME_MAX + 1;
 314         unique_ptr<char[]> buf(new char[size]);
 315         while (!should_quit) {
 316                 pollfd fds[2];
 317                 fds[0].fd = inotify_fd;
 318                 fds[0].events = POLLIN;
 319                 fds[0].revents = 0;
 320                 fds[1].fd = should_quit_fd;
 321                 fds[1].events = POLLIN;
 322                 fds[1].revents = 0;
 323
 324                 int ret = poll(fds, 2, -1);
 325                 if (ret == -1) {
 326                         if (errno == EINTR) {
 327                                 continue;
 328                         } else {
 329                                 perror("poll(inotify_fd)");
 330                                 return;
 331                         }
 332                 }
 333                 if (ret == 0) {
 334                         continue;
 335                 }
 336
 337                 if (fds[1].revents) break;  // should_quit_fd asserted.
 338
 339                 ret = read(inotify_fd, buf.get(), size);
 340                 if (ret == -1) {
 341                         if (errno == EINTR) {
 342                                 continue;
 343                         } else {
 344                                 perror("read(inotify_fd)");
 345                                 close(watch_fd);
 346                                 close(inotify_fd);
 347                                 return;
 348                         }
 349                 }
 350                 if (ret < int(sizeof(inotify_event))) {
 351                         fprintf(stderr, "inotify read unexpectedly returned %d, giving up hotplug of ALSA devices.\n",
 352                                 int(ret));
 353                         close(watch_fd);
 354                         close(inotify_fd);
 355                         return;
 356                 }
 357
 358                 for (int i = 0; i < ret; ) {
 359                         const inotify_event *event = reinterpret_cast<const inotify_event *>(&buf[i]);
 360                         i += sizeof(inotify_event) + event->len;
 361
 362                         if (event->mask & IN_Q_OVERFLOW) {
 363                                 fprintf(stderr, "WARNING: inotify overflowed, may lose ALSA hotplug events.\n");
 364                                 continue;
 365                         }
 366                         unsigned card, device;
 367                         char type;
 368                         if (sscanf(event->name, "pcmC%uD%u%c", &card, &device, &type) == 3 && type == 'c') {
 369                                 if (event->mask & (IN_MOVED_FROM | IN_DELETE)) {
 370                                         printf("Deleted capture device: Card %u, device %u\n", card, device);
 371                                         unplug_device(card, device);
 372                                 }
 373                                 if (event->mask & (IN_MOVED_TO | IN_CREATE)) {
 374                                         printf("Adding capture device: Card %u, device %u\n", card, device);
 375                                         probe_device_with_retry(card, device);
 376                                 }
 377                         }
 378                 }
 379         }
 380         close(watch_fd);
 381         close(inotify_fd);
 382         close(should_quit_fd);
 383 }
 384
 385 void ALSAPool::reset_device(unsigned index)
 386 {
 387         lock_guard<mutex> lock(mu);
 388         Device *device = &devices[index];
 389         if (inputs[index] != nullptr) {
 390                 inputs[index]->stop_capture_thread();
 391         }
 392         if (!device->held) {
 393                 inputs[index].reset();
 394         } else {
 395                 // TODO: Put on a background thread instead of locking?
 396                 auto callback = bind(&AudioMixer::add_audio, global_audio_mixer, DeviceSpec{InputSourceType::ALSA_INPUT, index}, _1, _2, _3, _4, _5);
 397                 inputs[index].reset(new ALSAInput(device->address.c_str(), OUTPUT_FREQUENCY, device->num_channels, callback, this, index));
 398                 inputs[index]->start_capture_thread();
 399         }
 400         device->input = inputs[index].get();
 401 }
 402
 403 unsigned ALSAPool::get_capture_frequency(unsigned index)
 404 {
 405         lock_guard<mutex> lock(mu);
 406         assert(devices[index].held);
 407         if (devices[index].input)
 408                 return devices[index].input->get_sample_rate();
 409         else
 410                 return OUTPUT_FREQUENCY;
 411 }
 412
 413 ALSAPool::Device::State ALSAPool::get_card_state(unsigned index)
 414 {
 415         lock_guard<mutex> lock(mu);
 416         assert(devices[index].held);
 417         return devices[index].state;
 418 }
 419
 420 void ALSAPool::set_card_state(unsigned index, ALSAPool::Device::State state)
 421 {
 422         {
 423                 lock_guard<mutex> lock(mu);
 424                 devices[index].state = state;
 425         }
 426
 427         DeviceSpec spec{InputSourceType::ALSA_INPUT, index};
 428         bool silence = (state != ALSAPool::Device::State::RUNNING);
 429         while (!global_audio_mixer->silence_card(spec, silence))
 430                 ;
 431         global_audio_mixer->trigger_state_changed_callback();
 432 }
 433
 434 unsigned ALSAPool::find_free_device_index(const string &name, const string &info, unsigned num_channels, const string &address)
 435 {
 436         // First try to find an exact match on a dead card.
 437         for (unsigned i = 0; i < devices.size(); ++i) {
 438                 if (devices[i].state == Device::State::DEAD &&
 439                     devices[i].address == address &&
 440                     devices[i].name == name &&
 441                     devices[i].info == info &&
 442                     devices[i].num_channels == num_channels) {
 443                         devices[i].state = Device::State::READY;
 444                         return i;
 445                 }
 446         }
 447
 448         // Then try to find a match on everything but the address
 449         // (probably that devices were plugged back in a different order).
 450         // If we have two cards that are equal, this might get them mixed up,
 451         // but we don't have anything better.
 452         for (unsigned i = 0; i < devices.size(); ++i) {
 453                 if (devices[i].state == Device::State::DEAD &&
 454                     devices[i].name == name &&
 455                     devices[i].info == info &&
 456                     devices[i].num_channels == num_channels) {
 457                         devices[i].state = Device::State::READY;
 458                         return i;
 459                 }
 460         }
 461
 462         // OK, so we didn't find a match; see if there are any empty slots.
 463         for (unsigned i = 0; i < devices.size(); ++i) {
 464                 if (devices[i].state == Device::State::EMPTY) {
 465                         devices[i].state = Device::State::READY;
 466                         devices[i].held = false;
 467                         return i;
 468                 }
 469         }
 470
 471         // Failing that, we just insert the new device at the end.
 472         Device new_dev;
 473         new_dev.state = Device::State::READY;
 474         new_dev.held = false;
 475         devices.push_back(new_dev);
 476         inputs.emplace_back(nullptr);
 477         return devices.size() - 1;
 478 }
 479
 480 unsigned ALSAPool::create_dead_card(const string &name, const string &info, unsigned num_channels)
 481 {
 482         lock_guard<mutex> lock(mu);
 483
 484         // See if there are any empty slots. If not, insert one at the end.
 485         vector<Device>::iterator free_device =
 486                 find_if(devices.begin(), devices.end(),
 487                         [](const Device &device) { return device.state == Device::State::EMPTY; });
 488         if (free_device == devices.end()) {
 489                 devices.push_back(Device());
 490                 inputs.emplace_back(nullptr);
 491                 free_device = devices.end() - 1;
 492         }
 493
 494         free_device->state = Device::State::DEAD;
 495         free_device->name = name;
 496         free_device->info = info;
 497         free_device->num_channels = num_channels;
 498         free_device->held = true;
 499
 500         return distance(devices.begin(), free_device);
 501 }
 502
 503 void ALSAPool::serialize_device(unsigned index, DeviceSpecProto *serialized)
 504 {
 505         lock_guard<mutex> lock(mu);
 506         assert(index < devices.size());
 507         assert(devices[index].held);
 508         serialized->set_type(DeviceSpecProto::ALSA_INPUT);
 509         serialized->set_index(index);
 510         serialized->set_display_name(devices[index].display_name());
 511         serialized->set_alsa_name(devices[index].name);
 512         serialized->set_alsa_info(devices[index].info);
 513         serialized->set_num_channels(devices[index].num_channels);
 514         serialized->set_address(devices[index].address);
 515 }
 516
 517 void ALSAPool::free_card(unsigned index)
 518 {
 519         DeviceSpec spec{InputSourceType::ALSA_INPUT, index};
 520         while (!global_audio_mixer->silence_card(spec, true))
 521                 ;
 522
 523         {
 524                 lock_guard<mutex> lock(mu);
 525                 if (devices[index].held) {
 526                         devices[index].state = Device::State::DEAD;
 527                 } else {
 528                         devices[index].state = Device::State::EMPTY;
 529                         inputs[index].reset();
 530                 }
 531                 while (!devices.empty() && devices.back().state == Device::State::EMPTY) {
 532                         devices.pop_back();
 533                         inputs.pop_back();
 534                 }
 535         }
 536
 537         global_audio_mixer->trigger_state_changed_callback();
 538 }