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

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