services/vr/bufferhubd/producer_channel.cpp

#include "producer_channel.h"

#include <log/log.h>
#include <sync/sync.h>
#include <sys/poll.h>
#include <utils/Trace.h>

#include <algorithm>
#include <atomic>
#include <thread>

#include <private/dvr/bufferhub_rpc.h>
#include "consumer_channel.h"

using android::pdx::BorrowedHandle;
using android::pdx::ErrorStatus;
using android::pdx::Message;
using android::pdx::RemoteChannelHandle;
using android::pdx::Status;
using android::pdx::rpc::BufferWrapper;
using android::pdx::rpc::DispatchRemoteMethod;
using android::pdx::rpc::WrapBuffer;

namespace android {
namespace dvr {

ProducerChannel::ProducerChannel(BufferHubService* service, int channel_id,
                                 uint32_t width, uint32_t height,
                                 uint32_t layer_count, uint32_t format,
                                 uint64_t usage, size_t meta_size_bytes,
                                 int* error)
    : BufferHubChannel(service, channel_id, channel_id, kProducerType),
      pending_consumers_(0),
      producer_owns_(true),
      meta_size_bytes_(meta_size_bytes),
      meta_(meta_size_bytes ? new uint8_t[meta_size_bytes] : nullptr) {
  const int ret = buffer_.Alloc(width, height, layer_count, format, usage);
  if (ret < 0) {
    ALOGE("ProducerChannel::ProducerChannel: Failed to allocate buffer: %s",
          strerror(-ret));
    *error = ret;
    return;
  }

  // Success.
  *error = 0;
}

Status<std::shared_ptr<ProducerChannel>> ProducerChannel::Create(
    BufferHubService* service, int channel_id, uint32_t width, uint32_t height,
    uint32_t layer_count, uint32_t format, uint64_t usage,
    size_t meta_size_bytes) {
  int error;
  std::shared_ptr<ProducerChannel> producer(
      new ProducerChannel(service, channel_id, width, height, layer_count,
                          format, usage, meta_size_bytes, &error));
  if (error < 0)
    return ErrorStatus(-error);
  else
    return {std::move(producer)};
}

ProducerChannel::~ProducerChannel() {
  ALOGD_IF(TRACE,
           "ProducerChannel::~ProducerChannel: channel_id=%d buffer_id=%d",
           channel_id(), buffer_id());
  for (auto consumer : consumer_channels_)
    consumer->OnProducerClosed();
}

BufferHubChannel::BufferInfo ProducerChannel::GetBufferInfo() const {
  return BufferInfo(buffer_id(), consumer_channels_.size(), buffer_.width(),
                    buffer_.height(), buffer_.layer_count(), buffer_.format(),
                    buffer_.usage(), name_);
}

void ProducerChannel::HandleImpulse(Message& message) {
  ATRACE_NAME("ProducerChannel::HandleImpulse");
  switch (message.GetOp()) {
    case BufferHubRPC::ProducerGain::Opcode:
      OnProducerGain(message);
      break;
  }
}

bool ProducerChannel::HandleMessage(Message& message) {
  ATRACE_NAME("ProducerChannel::HandleMessage");
  switch (message.GetOp()) {
    case BufferHubRPC::GetBuffer::Opcode:
      DispatchRemoteMethod<BufferHubRPC::GetBuffer>(
          *this, &ProducerChannel::OnGetBuffer, message);
      return true;

    case BufferHubRPC::NewConsumer::Opcode:
      DispatchRemoteMethod<BufferHubRPC::NewConsumer>(
          *this, &ProducerChannel::OnNewConsumer, message);
      return true;

    case BufferHubRPC::ProducerPost::Opcode:
      DispatchRemoteMethod<BufferHubRPC::ProducerPost>(
          *this, &ProducerChannel::OnProducerPost, message);
      return true;

    case BufferHubRPC::ProducerGain::Opcode:
      DispatchRemoteMethod<BufferHubRPC::ProducerGain>(
          *this, &ProducerChannel::OnProducerGain, message);
      return true;

    case BufferHubRPC::ProducerMakePersistent::Opcode:
      DispatchRemoteMethod<BufferHubRPC::ProducerMakePersistent>(
          *this, &ProducerChannel::OnProducerMakePersistent, message);
      return true;

    case BufferHubRPC::ProducerRemovePersistence::Opcode:
      DispatchRemoteMethod<BufferHubRPC::ProducerRemovePersistence>(
          *this, &ProducerChannel::OnRemovePersistence, message);
      return true;

    default:
      return false;
  }
}

Status<NativeBufferHandle<BorrowedHandle>> ProducerChannel::OnGetBuffer(
    Message& /*message*/) {
  ATRACE_NAME("ProducerChannel::OnGetBuffer");
  ALOGD_IF(TRACE, "ProducerChannel::OnGetBuffer: buffer=%d", buffer_id());
  return {NativeBufferHandle<BorrowedHandle>(buffer_, buffer_id())};
}

Status<RemoteChannelHandle> ProducerChannel::CreateConsumer(Message& message) {
  ATRACE_NAME("ProducerChannel::CreateConsumer");
  ALOGD_IF(TRACE, "ProducerChannel::CreateConsumer: buffer_id=%d", buffer_id());

  int channel_id;
  auto status = message.PushChannel(0, nullptr, &channel_id);
  if (!status) {
    ALOGE(
        "ProducerChannel::CreateConsumer: Failed to push consumer channel: %s",
        status.GetErrorMessage().c_str());
    return ErrorStatus(ENOMEM);
  }

  auto consumer = std::make_shared<ConsumerChannel>(
      service(), buffer_id(), channel_id, shared_from_this());
  const auto channel_status = service()->SetChannel(channel_id, consumer);
  if (!channel_status) {
    ALOGE(
        "ProducerChannel::CreateConsumer: failed to set new consumer channel: "
        "%s",
        channel_status.GetErrorMessage().c_str());
    return ErrorStatus(ENOMEM);
  }

  if (!producer_owns_) {
    // Signal the new consumer when adding it to a posted producer.
    if (consumer->OnProducerPosted())
      pending_consumers_++;
  }

  return {status.take()};
}

Status<RemoteChannelHandle> ProducerChannel::OnNewConsumer(Message& message) {
  ATRACE_NAME("ProducerChannel::OnNewConsumer");
  ALOGD_IF(TRACE, "ProducerChannel::OnNewConsumer: buffer_id=%d", buffer_id());
  return CreateConsumer(message);
}

Status<void> ProducerChannel::OnProducerPost(
    Message&, LocalFence acquire_fence,
    BufferWrapper<std::vector<std::uint8_t>> metadata) {
  ATRACE_NAME("ProducerChannel::OnProducerPost");
  ALOGD_IF(TRACE, "ProducerChannel::OnProducerPost: buffer_id=%d", buffer_id());
  if (!producer_owns_) {
    ALOGE("ProducerChannel::OnProducerPost: Not in gained state!");
    return ErrorStatus(EBUSY);
  }

  if (meta_size_bytes_ != metadata.size()) {
    ALOGD_IF(TRACE,
             "ProducerChannel::OnProducerPost: Expected meta_size_bytes=%zu "
             "got size=%zu",
             meta_size_bytes_, metadata.size());
    return ErrorStatus(EINVAL);
  }

  std::copy(metadata.begin(), metadata.end(), meta_.get());
  post_fence_ = std::move(acquire_fence);
  producer_owns_ = false;

  // Signal any interested consumers. If there are none, automatically release
  // the buffer.
  pending_consumers_ = 0;
  for (auto consumer : consumer_channels_) {
    if (consumer->OnProducerPosted())
      pending_consumers_++;
  }
  if (pending_consumers_ == 0)
    SignalAvailable();
  ALOGD_IF(TRACE, "ProducerChannel::OnProducerPost: %d pending consumers",
           pending_consumers_);

  return {};
}

Status<LocalFence> ProducerChannel::OnProducerGain(Message& /*message*/) {
  ATRACE_NAME("ProducerChannel::OnGain");
  ALOGD_IF(TRACE, "ProducerChannel::OnGain: buffer_id=%d", buffer_id());
  if (producer_owns_) {
    ALOGE("ProducerChanneL::OnGain: Already in gained state: channel=%d",
          channel_id());
    return ErrorStatus(EALREADY);
  }

  // There are still pending consumers, return busy.
  if (pending_consumers_ > 0)
    return ErrorStatus(EBUSY);

  ClearAvailable();
  producer_owns_ = true;
  post_fence_.close();
  return {std::move(returned_fence_)};
}

Status<std::pair<BorrowedFence, BufferWrapper<std::uint8_t*>>>
ProducerChannel::OnConsumerAcquire(Message& /*message*/,
                                   std::size_t metadata_size) {
  ATRACE_NAME("ProducerChannel::OnConsumerAcquire");
  ALOGD_IF(TRACE, "ProducerChannel::OnConsumerAcquire: buffer_id=%d",
           buffer_id());
  if (producer_owns_) {
    ALOGE("ProducerChannel::OnConsumerAcquire: Not in posted state!");
    return ErrorStatus(EBUSY);
  }

  // Return a borrowed fd to avoid unnecessary duplication of the underlying fd.
  // Serialization just needs to read the handle.
  if (metadata_size == 0)
    return {std::make_pair(post_fence_.borrow(),
                           WrapBuffer<std::uint8_t>(nullptr, 0))};
  else
    return {std::make_pair(post_fence_.borrow(),
                           WrapBuffer(meta_.get(), meta_size_bytes_))};
}

Status<void> ProducerChannel::OnConsumerRelease(Message&,
                                                LocalFence release_fence) {
  ATRACE_NAME("ProducerChannel::OnConsumerRelease");
  ALOGD_IF(TRACE, "ProducerChannel::OnConsumerRelease: buffer_id=%d",
           buffer_id());
  if (producer_owns_) {
    ALOGE("ProducerChannel::OnConsumerRelease: Not in acquired state!");
    return ErrorStatus(EBUSY);
  }

  // Attempt to merge the fences if necessary.
  if (release_fence) {
    if (returned_fence_) {
      LocalFence merged_fence(sync_merge("bufferhub_merged",
                                         returned_fence_.get_fd(),
                                         release_fence.get_fd()));
      const int error = errno;
      if (!merged_fence) {
        ALOGE("ProducerChannel::OnConsumerRelease: Failed to merge fences: %s",
              strerror(error));
        return ErrorStatus(error);
      }
      returned_fence_ = std::move(merged_fence);
    } else {
      returned_fence_ = std::move(release_fence);
    }
  }

  OnConsumerIgnored();
  return {};
}

void ProducerChannel::OnConsumerIgnored() {
  if (!--pending_consumers_)
    SignalAvailable();
  ALOGD_IF(TRACE,
           "ProducerChannel::OnConsumerIgnored: buffer_id=%d %d consumers left",
           buffer_id(), pending_consumers_);
}

Status<void> ProducerChannel::OnProducerMakePersistent(Message& message,
                                                       const std::string& name,
                                                       int user_id,
                                                       int group_id) {
  ATRACE_NAME("ProducerChannel::OnProducerMakePersistent");
  ALOGD_IF(TRACE,
           "ProducerChannel::OnProducerMakePersistent: buffer_id=%d name=%s "
           "user_id=%d group_id=%d",
           buffer_id(), name.c_str(), user_id, group_id);

  if (name.empty() || (user_id < 0 && user_id != kNoCheckId) ||
      (group_id < 0 && group_id != kNoCheckId)) {
    return ErrorStatus(EINVAL);
  }

  // Try to add this buffer with the requested name.
  if (service()->AddNamedBuffer(name, std::static_pointer_cast<ProducerChannel>(
                                          shared_from_this()))) {
    // If successful, set the requested permissions.

    // A value of zero indicates that the ids from the sending process should be
    // used.
    if (user_id == kUseCallerId)
      user_id = message.GetEffectiveUserId();
    if (group_id == kUseCallerId)
      group_id = message.GetEffectiveGroupId();

    owner_user_id_ = user_id;
    owner_group_id_ = group_id;
    name_ = name;
    return {};
  } else {
    // Otherwise a buffer with that name already exists.
    return ErrorStatus(EALREADY);
  }
}

Status<void> ProducerChannel::OnRemovePersistence(Message&) {
  if (service()->RemoveNamedBuffer(*this))
    return {};
  else
    return ErrorStatus(ENOENT);
}

void ProducerChannel::AddConsumer(ConsumerChannel* channel) {
  consumer_channels_.push_back(channel);
}

void ProducerChannel::RemoveConsumer(ConsumerChannel* channel) {
  consumer_channels_.erase(
      std::find(consumer_channels_.begin(), consumer_channels_.end(), channel));
}

// Returns true if either the user or group ids match the owning ids or both
// owning ids are not set, in which case access control does not apply.
bool ProducerChannel::CheckAccess(int euid, int egid) {
  const bool no_check =
      owner_user_id_ == kNoCheckId && owner_group_id_ == kNoCheckId;
  const bool euid_check = euid == owner_user_id_ || euid == kRootId;
  const bool egid_check = egid == owner_group_id_ || egid == kRootId;
  return no_check || euid_check || egid_check;
}

// Returns true if the given parameters match the underlying buffer parameters.
bool ProducerChannel::CheckParameters(uint32_t width, uint32_t height,
                                      uint32_t layer_count, uint32_t format,
                                      uint64_t usage, size_t meta_size_bytes) {
  return meta_size_bytes == meta_size_bytes_ && buffer_.width() == width &&
         buffer_.height() == height && buffer_.layer_count() == layer_count &&
         buffer_.format() == format && buffer_.usage() == usage;
}

}  // namespace dvr
}  // namespace android