/* SPDX-License-Identifier: LGPL-2.1-or-later */ /* * Copyright (C) 2018, Google Inc. * * media_device.cpp - Media device handler */ #include "libcamera/internal/media_device.h" #include #include #include #include #include #include #include #include #include #include /** * \file media_device.h * \brief Provide a representation of a Linux kernel Media Controller device * that exposes the full graph topology. */ namespace libcamera { LOG_DEFINE_CATEGORY(MediaDevice) /** * \class MediaDevice * \brief The MediaDevice represents a Media Controller device with its full * graph of connected objects. * * A MediaDevice instance is associated with a media controller device node when * created, and that association is kept for the lifetime of the MediaDevice * instance. * * The instance is created with an empty media graph. Before performing any * other operation, it must be populate by calling populate(). Instances of * MediaEntity, MediaPad and MediaLink are created to model the media graph, * and stored in a map indexed by object id. * * The graph is valid once successfully populated, as reported by the isValid() * function. It can be queried to list all entities(), or entities can be * looked up by name with getEntityByName(). The graph can be traversed from * entity to entity through pads and links as exposed by the corresponding * classes. * * Media devices can be claimed for exclusive use with acquire(), released with * release() and tested with busy(). This mechanism is aimed at pipeline * managers to claim media devices they support during enumeration. */ /** * \brief Construct a MediaDevice * \param[in] deviceNode The media device node path * * Once constructed the media device is invalid, and must be populated with * populate() before the media graph can be queried. */ MediaDevice::MediaDevice(const std::string &deviceNode) : deviceNode_(deviceNode), valid_(false), acquired_(false) { } MediaDevice::~MediaDevice() { fd_.reset(); clear(); } std::string MediaDevice::logPrefix() const { return deviceNode() + "[" + driver() + "]"; } /** * \brief Claim a device for exclusive use * * The device claiming mechanism offers simple media device access arbitration * between multiple users. When the media device is created, it is available to * all users. Users can query the media graph to determine whether they can * support the device and, if they do, claim the device for exclusive use. Other * users are then expected to skip over media devices in use as reported by the * busy() function. * * Once claimed the device shall be released by its user when not needed anymore * by calling the release() function. Acquiring the media device opens a file * descriptor to the device which is kept open until release() is called. * * Exclusive access is only guaranteed if all users of the media device abide by * the device claiming mechanism, as it isn't enforced by the media device * itself. * * \return true if the device was successfully claimed, or false if it was * already in use * \sa release(), busy() */ bool MediaDevice::acquire() { if (acquired_) return false; if (open()) return false; acquired_ = true; return true; } /** * \brief Release a device previously claimed for exclusive use * \sa acquire(), busy() */ void MediaDevice::release() { close(); acquired_ = false; } /** * \brief Lock the device to prevent it from being used by other instances of * libcamera * * Multiple instances of libcamera might be running on the same system, at the * same time. To allow the different instances to coexist, system resources in * the form of media devices must be accessible for enumerating the cameras * they provide at all times, while still allowing an instance to lock a * resource while it prepares to actively use a camera from the resource. * * This function shall not be called from a pipeline handler implementation * directly, as the base PipelineHandler implementation handles this on the * behalf of the specified implementation. * * \return True if the device could be locked, false otherwise * \sa unlock() */ bool MediaDevice::lock() { if (!fd_.isValid()) return false; if (lockf(fd_.get(), F_TLOCK, 0)) return false; return true; } /** * \brief Unlock the device and free it for use for libcamera instances * * This function shall not be called from a pipeline handler implementation * directly, as the base PipelineHandler implementation handles this on the * behalf of the specified implementation. * * \sa lock() */ void MediaDevice::unlock() { if (!fd_.isValid()) return; lockf(fd_.get(), F_ULOCK, 0); } /** * \fn MediaDevice::busy() * \brief Check if a device is in use * \return true if the device has been claimed for exclusive use, or false if it * is available * \sa acquire(), release() */ /** * \brief Populate the MediaDevice with device information and media objects * * This function retrieves the media device information and enumerates all * media objects in the media device graph and creates their MediaObject * representations. All entities, pads and links are stored as MediaEntity, * MediaPad and MediaLink respectively, with cross-references between objects. * Interfaces are not processed. * * Entities are stored in a separate list in the MediaDevice to ease lookup, * while pads are accessible from the entity they belong to and links from the * pads they connect. * * \return 0 on success or a negative error code otherwise */ int MediaDevice::populate() { struct media_v2_topology topology = {}; struct media_v2_entity *ents = nullptr; struct media_v2_interface *interfaces = nullptr; struct media_v2_link *links = nullptr; struct media_v2_pad *pads = nullptr; __u64 version = -1; int ret; clear(); ret = open(); if (ret) return ret; struct media_device_info info = {}; ret = ioctl(fd_.get(), MEDIA_IOC_DEVICE_INFO, &info); if (ret) { ret = -errno; LOG(MediaDevice, Error) << "Failed to get media device info " << strerror(-ret); goto done; } driver_ = info.driver; model_ = info.model; version_ = info.media_version; hwRevision_ = info.hw_revision; /* * Keep calling G_TOPOLOGY until the version number stays stable. */ while (true) { topology.topology_version = 0; topology.ptr_entities = reinterpret_cast(ents); topology.ptr_interfaces = reinterpret_cast(interfaces); topology.ptr_links = reinterpret_cast(links); topology.ptr_pads = reinterpret_cast(pads); ret = ioctl(fd_.get(), MEDIA_IOC_G_TOPOLOGY, &topology); if (ret < 0) { ret = -errno; LOG(MediaDevice, Error) << "Failed to enumerate topology: " << strerror(-ret); goto done; } if (version == topology.topology_version) break; delete[] ents; delete[] interfaces; delete[] pads; delete[] links; ents = new struct media_v2_entity[topology.num_entities](); interfaces = new struct media_v2_interface[topology.num_interfaces](); links = new struct media_v2_link[topology.num_links](); pads = new struct media_v2_pad[topology.num_pads](); version = topology.topology_version; } /* Populate entities, pads and links. */ if (populateEntities(topology) && populatePads(topology) && populateLinks(topology)) valid_ = true; ret = 0; done: close(); delete[] ents; delete[] interfaces; delete[] pads; delete[] links; if (!valid_) { clear(); return -EINVAL; } return ret; } /** * \fn MediaDevice::isValid() * \brief Query whether the media graph has been populated and is valid * \return true if the media graph is valid, false otherwise */ /** * \fn MediaDevice::driver() * \brief Retrieve the media device driver name * \return The name of the kernel driver that handles the MediaDevice */ /** * \fn MediaDevice::deviceNode() * \brief Retrieve the media device node path * \return The MediaDevice deviceNode path */ /** * \fn MediaDevice::model() * \brief Retrieve the media device model name * \return The MediaDevice model name */ /** * \fn MediaDevice::version() * \brief Retrieve the media device API version * * The version is formatted with the KERNEL_VERSION() macro. * * \return The MediaDevice API version */ /** * \fn MediaDevice::hwRevision() * \brief Retrieve the media device hardware revision * * The hardware revision is in a driver-specific format. * * \return The MediaDevice hardware revision */ /** * \fn MediaDevice::entities() * \brief Retrieve the list of entities in the media graph * \return The list of MediaEntities registered in the MediaDevice */ /** * \brief Return the MediaEntity with name \a name * \param[in] name The entity name * \return The entity with \a name, or nullptr if no such entity is found */ MediaEntity *MediaDevice::getEntityByName(const std::string &name) const { for (MediaEntity *e : entities_) if (e->name() == name) return e; return nullptr; } /** * \brief Retrieve the MediaLink connecting two pads, identified by entity * names and pad indexes * \param[in] sourceName The source entity name * \param[in] sourceIdx The index of the source pad * \param[in] sinkName The sink entity name * \param[in] sinkIdx The index of the sink pad * * Find the link that connects the pads at index \a sourceIdx of the source * entity with name \a sourceName, to the pad at index \a sinkIdx of the * sink entity with name \a sinkName, if any. * * \sa link(const MediaEntity *source, unsigned int sourceIdx, * const MediaEntity *sink, unsigned int sinkIdx) * \sa link(const MediaPad *source, const MediaPad *sink) * * \return The link that connects the two pads, or nullptr if no such a link * exists */ MediaLink *MediaDevice::link(const std::string &sourceName, unsigned int sourceIdx, const std::string &sinkName, unsigned int sinkIdx) { const MediaEntity *source = getEntityByName(sourceName); const MediaEntity *sink = getEntityByName(sinkName); if (!source || !sink) return nullptr; return link(source, sourceIdx, sink, sinkIdx); } /** * \brief Retrieve the MediaLink connecting two pads, identified by the * entities they belong to and pad indexes * \param[in] source The source entity * \param[in] sourceIdx The index of the source pad * \param[in] sink The sink entity * \param[in] sinkIdx The index of the sink pad * * Find the link that connects the pads at index \a sourceIdx of the source * entity \a source, to the pad at index \a sinkIdx of the sink entity \a * sink, if any. * * \sa link(const std::string &sourceName, unsigned int sourceIdx, * const std::string &sinkName, unsigned int sinkIdx) * \sa link(const MediaPad *source, const MediaPad *sink) * * \return The link that connects the two pads, or nullptr if no such a link * exists */ MediaLink *MediaDevice::link(const MediaEntity *source, unsigned int sourceIdx, const MediaEntity *sink, unsigned int sinkIdx) { const MediaPad *sourcePad = source->getPadByIndex(sourceIdx); const MediaPad *sinkPad = sink->getPadByIndex(sinkIdx); if (!sourcePad || !sinkPad) return nullptr; return link(sourcePad, sinkPad); } /** * \brief Retrieve the MediaLink that connects two pads * \param[in] source The source pad * \param[in] sink The sink pad * * \sa link(const std::string &sourceName, unsigned int sourceIdx, * const std::string &sinkName, unsigned int sinkIdx) * \sa link(const MediaEntity *source, unsigned int sourceIdx, * const MediaEntity *sink, unsigned int sinkIdx) * * \return The link that connects the two pads, or nullptr if no such a link * exists */ MediaLink *MediaDevice::link(const MediaPad *source, const MediaPad *sink) { for (MediaLink *link : source->links()) { if (link->sink()->id() == sink->id()) return link; } return nullptr; } /** * \brief Disable all links in the media device * * Disable all the media device links, clearing the MEDIA_LNK_FL_ENABLED flag * on links which are not flagged as IMMUTABLE. * * \return 0 on success or a negative error code otherwise */ int MediaDevice::disableLinks() { for (MediaEntity *entity : entities_) { for (MediaPad *pad : entity->pads()) { if (!(pad->flags() & MEDIA_PAD_FL_SOURCE)) continue; for (MediaLink *link : pad->links()) { if (link->flags() & MEDIA_LNK_FL_IMMUTABLE) continue; int ret = link->setEnabled(false); if (ret) return ret; } } } return 0; } /** * \var MediaDevice::disconnected * \brief Signal emitted when the media device is disconnected from the system * * This signal is emitted when the device enumerator detects that the media * device has been removed from the system. For hot-pluggable devices this is * usually caused by physical device disconnection, but can also result from * driver unloading for most devices. The media device is passed as a parameter. */ /** * \brief Open the media device * * \return 0 on success or a negative error code otherwise * \retval -EBUSY Media device already open * \sa close() */ int MediaDevice::open() { if (fd_.isValid()) { LOG(MediaDevice, Error) << "MediaDevice already open"; return -EBUSY; } fd_ = UniqueFD(::open(deviceNode_.c_str(), O_RDWR)); if (!fd_.isValid()) { int ret = -errno; LOG(MediaDevice, Error) << "Failed to open media device at " << deviceNode_ << ": " << strerror(-ret); return ret; } return 0; } /** * \brief Close the media device * * This function closes the media device node. It does not invalidate the media * graph and all cached media objects remain valid and can be accessed normally. * Once closed no operation interacting with the media device node can be * performed until the device is opened again. * * Closing an already closed device is allowed and will not perform any * operation. * * \sa open() */ void MediaDevice::close() { fd_.reset(); } /** * \var MediaDevice::objects_ * \brief Global map of media objects (entities, pads, links) keyed by their * object id. */ /** * \brief Retrieve the media graph object specified by \a id * \return The graph object, or nullptr if no object with \a id is found */ MediaObject *MediaDevice::object(unsigned int id) { auto it = objects_.find(id); return (it == objects_.end()) ? nullptr : it->second; } /** * \brief Add a media object to the media graph * * If the \a object has a unique id it is added to the media graph, and its * lifetime will be managed by the media device. Otherwise the object isn't * added to the graph and the caller must delete it. * * \return true if the object was successfully added to the graph and false * otherwise */ bool MediaDevice::addObject(MediaObject *object) { if (objects_.find(object->id()) != objects_.end()) { LOG(MediaDevice, Error) << "Element with id " << object->id() << " already enumerated."; return false; } objects_[object->id()] = object; return true; } /** * \brief Delete all graph objects in the media device * * Clear the media graph and delete all the objects it contains. After this * function returns any previously obtained pointer to a media graph object * becomes invalid. * * The media device graph state is reset to invalid when the graph is cleared. * * \sa isValid() */ void MediaDevice::clear() { for (auto const &o : objects_) delete o.second; objects_.clear(); entities_.clear(); valid_ = false; } /** * \var MediaDevice::entities_ * \brief Global list of media entities in the media graph */ /** * \brief Find the interface associated with an entity * \param[in] topology The media topology as returned by MEDIA_IOC_G_TOPOLOGY * \param[in] entityId The entity id * \return A pointer to the interface if found, or nullptr otherwise */ struct media_v2_interface *MediaDevice::findInterface(const struct media_v2_topology &topology, unsigned int entityId) { struct media_v2_link *links = reinterpret_cast (topology.ptr_links); unsigned int ifaceId = 0; unsigned int i; for (i = 0; i < topology.num_links; ++i) { /* Search for the interface to entity link. */ if (links[i].sink_id != entityId) continue; if ((links[i].flags & MEDIA_LNK_FL_LINK_TYPE) != MEDIA_LNK_FL_INTERFACE_LINK) continue; ifaceId = links[i].source_id; break; } if (i == topology.num_links) return nullptr; struct media_v2_interface *ifaces = reinterpret_cast (topology.ptr_interfaces); for (i = 0; i < topology.num_interfaces; ++i) { if (ifaces[i].id == ifaceId) return &ifaces[i]; } return nullptr; } /* * For each entity in the media graph create a MediaEntity and store a * reference in the media device objects map and entities list. */ bool MediaDevice::populateEntities(const struct media_v2_topology &topology) { struct media_v2_entity *mediaEntities = reinterpret_cast (topology.ptr_entities); for (unsigned int i = 0; i < topology.num_entities; ++i) { struct media_v2_entity *ent = &mediaEntities[i]; /* * The media_v2_entity structure was missing the flag field before * v4.19. */ if (!MEDIA_V2_ENTITY_HAS_FLAGS(version_)) fixupEntityFlags(ent); /* * Find the interface linked to this entity to get the device * node major and minor numbers. */ struct media_v2_interface *iface = findInterface(topology, ent->id); MediaEntity *entity = new MediaEntity(this, ent, iface); if (!addObject(entity)) { delete entity; return false; } entities_.push_back(entity); } return true; } bool MediaDevice::populatePads(const struct media_v2_topology &topology) { struct media_v2_pad *mediaPads = reinterpret_cast (topology.ptr_pads); for (unsigned int i = 0; i < topology.num_pads; ++i) { unsigned int entity_id = mediaPads[i].entity_id; /* Store a reference to this MediaPad in entity. */ MediaEntity *mediaEntity = dynamic_cast (object(entity_id)); if (!mediaEntity) { LOG(MediaDevice, Error) << "Failed to find entity with id: " << entity_id; return false; } MediaPad *pad = new MediaPad(&mediaPads[i], mediaEntity); if (!addObject(pad)) { delete pad; return false; } mediaEntity->addPad(pad); } return true; } bool MediaDevice::populateLinks(const struct media_v2_topology &topology) { struct media_v2_link *mediaLinks = reinterpret_cast (topology.ptr_links); for (unsigned int i = 0; i < topology.num_links; ++i) { if ((mediaLinks[i].flags & MEDIA_LNK_FL_LINK_TYPE) == MEDIA_LNK_FL_INTERFACE_LINK) continue; /* Look up the source and sink objects. */ unsigned int source_id = mediaLinks[i].source_id; MediaObject *source = object(source_id); if (!source) { LOG(MediaDevice, Error) << "Failed to find MediaObject with id " << source_id; return false; } unsigned int sink_id = mediaLinks[i].sink_id; MediaObject *sink = object(sink_id); if (!sink) { LOG(MediaDevice, Error) << "Failed to find MediaObject with id " << sink_id; return false; } switch (mediaLinks[i].flags & MEDIA_LNK_FL_LINK_TYPE) { case MEDIA_LNK_FL_DATA_LINK: { MediaPad *sourcePad = dynamic_cast(source); MediaPad *sinkPad = dynamic_cast(sink); if (!source || !sink) { LOG(MediaDevice, Error) << "Source or sink is not a pad"; return false; } MediaLink *link = new MediaLink(&mediaLinks[i], sourcePad, sinkPad); if (!addObject(link)) { delete link; return false; } link->source()->addLink(link); link->sink()->addLink(link); break; } case MEDIA_LNK_FL_ANCILLARY_LINK: { MediaEntity *primary = dynamic_cast(source); MediaEntity *ancillary = dynamic_cast(sink); if (!primary || !ancillary) { LOG(MediaDevice, Error) << "Source or sink is not an entity"; return false; } primary->addAncillaryEntity(ancillary); break; } default: LOG(MediaDevice, Warning) << "Unknown media link type"; break; } } return true; } /** * \brief Fixup entity flags using the legacy API * \param[in] entity The entity * * This function is used as a fallback to query entity flags using the legacy * MEDIA_IOC_ENUM_ENTITIES ioctl when running on a kernel version that doesn't * provide them through the MEDIA_IOC_G_TOPOLOGY ioctl. */ void MediaDevice::fixupEntityFlags(struct media_v2_entity *entity) { struct media_entity_desc desc = {}; desc.id = entity->id; int ret = ioctl(fd_.get(), MEDIA_IOC_ENUM_ENTITIES, &desc); if (ret < 0) { ret = -errno; LOG(MediaDevice, Debug) << "Failed to retrieve information for entity " << entity->id << ": " << strerror(-ret); return; } entity->flags = desc.flags; } /** * \brief Apply \a flags to a link between two pads * \param[in] link The link to apply flags to * \param[in] flags The flags to apply to the link * * This function applies the link \a flags (as defined by the MEDIA_LNK_FL_* * macros from the Media Controller API) to the given \a link. It implements * low-level link setup as it performs no checks on the validity of the \a * flags, and assumes that the supplied \a flags are valid for the link (e.g. * immutable links cannot be disabled). * * \sa MediaLink::setEnabled(bool enable) * * \return 0 on success or a negative error code otherwise */ int MediaDevice::setupLink(const MediaLink *link, unsigned int flags) { struct media_link_desc linkDesc = {}; MediaPad *source = link->source(); MediaPad *sink = link->sink(); linkDesc.source.entity = source->entity()->id(); linkDesc.source.index = source->index(); linkDesc.source.flags = MEDIA_PAD_FL_SOURCE; linkDesc.sink.entity = sink->entity()->id(); linkDesc.sink.index = sink->index(); linkDesc.sink.flags = MEDIA_PAD_FL_SINK; linkDesc.flags = flags; int ret = ioctl(fd_.get(), MEDIA_IOC_SETUP_LINK, &linkDesc); if (ret) { ret = -errno; LOG(MediaDevice, Error) << "Failed to setup link " << source->entity()->name() << "[" << source->index() << "] -> " << sink->entity()->name() << "[" << sink->index() << "]: " << strerror(-ret); return ret; } LOG(MediaDevice, Debug) << source->entity()->name() << "[" << source->index() << "] -> " << sink->entity()->name() << "[" << sink->index() << "]: " << flags; return 0; } } /* namespace libcamera */ id='n583' href='#n583'>583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941

/* SPDX-License-Identifier: LGPL-2.1-or-later */
/*
 * Copyright (C) 2019, Google Inc.
 *
 * Proxy to V4L2 compatibility camera
 */

#include "v4l2_camera_proxy.h"

#include <algorithm>
#include <errno.h>
#include <numeric>
#include <set>
#include <string.h>
#include <sys/mman.h>
#include <unistd.h>

#include <linux/videodev2.h>

#include <libcamera/base/log.h>
#include <libcamera/base/object.h>
#include <libcamera/base/utils.h>

#include <libcamera/camera.h>
#include <libcamera/control_ids.h>
#include <libcamera/controls.h>
#include <libcamera/formats.h>

#include "libcamera/internal/v4l2_pixelformat.h"

#include "v4l2_camera.h"
#include "v4l2_camera_file.h"
#include "v4l2_compat_manager.h"

#define KERNEL_VERSION(a, b, c) (((a) << 16) + ((b) << 8) + (c))

using namespace libcamera;
using namespace std::literals::chrono_literals;

LOG_DECLARE_CATEGORY(V4L2Compat)

V4L2CameraProxy::V4L2CameraProxy(unsigned int index,
				 std::shared_ptr<Camera> camera)
	: refcount_(0), index_(index), bufferCount_(0), currentBuf_(0),
	  vcam_(std::make_unique<V4L2Camera>(camera)), owner_(nullptr)
{
	querycap(camera);
}

int V4L2CameraProxy::open(V4L2CameraFile *file)
{
	LOG(V4L2Compat, Debug)
		<< "[" << file->description() << "] " << __func__ << "()";

	MutexLocker locker(proxyMutex_);

	if (refcount_++) {
		files_.insert(file);
		return 0;
	}

	/*
	 * We open the camera here, once, and keep it open until the last
	 * V4L2CameraFile is closed. The proxy is initially not owned by any
	 * file. The first file that calls reqbufs with count > 0 or s_fmt
	 * will become the owner, and no other file will be allowed to call
	 * buffer-related ioctls (except querybuf), set the format, or start or
	 * stop the stream until ownership is released with a call to reqbufs
	 * with count = 0.
	 */

	int ret = vcam_->open(&streamConfig_);
	if (ret < 0) {
		refcount_--;
		return ret;
	}

	setFmtFromConfig(streamConfig_);

	files_.insert(file);

	return 0;
}

void V4L2CameraProxy::close(V4L2CameraFile *file)
{
	LOG(V4L2Compat, Debug)
		<< "[" << file->description() << "] " << __func__ << "()";

	MutexLocker locker(proxyMutex_);

	files_.erase(file);

	release(file);

	if (--refcount_ > 0)
		return;

	vcam_->close();
}

void *V4L2CameraProxy::mmap(V4L2CameraFile *file, void *addr, size_t length,
			    int prot, int flags, off64_t offset)
{
	LOG(V4L2Compat, Debug)
		<< "[" << file->description() << "] " << __func__ << "()";

	MutexLocker locker(proxyMutex_);

	/*
	 * Mimic the videobuf2 behaviour, which requires PROT_READ and
	 * MAP_SHARED.
	 */
	if (!(prot & PROT_READ)) {
		errno = EINVAL;
		return MAP_FAILED;
	}

	if (!(flags & MAP_SHARED)) {
		errno = EINVAL;
		return MAP_FAILED;
	}

	unsigned int index = offset / sizeimage_;
	if (static_cast<off_t>(index * sizeimage_) != offset ||
	    length != sizeimage_) {
		errno = EINVAL;
		return MAP_FAILED;
	}

	int fd = vcam_->getBufferFd(index);
	if (fd < 0) {
		errno = EINVAL;
		return MAP_FAILED;
	}

	void *map = V4L2CompatManager::instance()->fops().mmap(addr, length, prot,
							       flags, fd, 0);
	if (map == MAP_FAILED)
		return map;

	buffers_[index].flags |= V4L2_BUF_FLAG_MAPPED;
	mmaps_[map] = index;

	return map;
}

int V4L2CameraProxy::munmap(V4L2CameraFile *file, void *addr, size_t length)
{
	LOG(V4L2Compat, Debug)
		<< "[" << file->description() << "] " << __func__ << "()";

	MutexLocker locker(proxyMutex_);

	auto iter = mmaps_.find(addr);
	if (iter == mmaps_.end() || length != sizeimage_) {
		errno = EINVAL;
		return -1;
	}

	if (V4L2CompatManager::instance()->fops().munmap(addr, length))
		LOG(V4L2Compat, Error) << "Failed to unmap " << addr
				       << " with length " << length;

	buffers_[iter->second].flags &= ~V4L2_BUF_FLAG_MAPPED;
	mmaps_.erase(iter);

	return 0;
}

bool V4L2CameraProxy::validateBufferType(uint32_t type)
{
	return type == V4L2_BUF_TYPE_VIDEO_CAPTURE;
}

bool V4L2CameraProxy::validateMemoryType(uint32_t memory)
{
	return memory == V4L2_MEMORY_MMAP;
}

void V4L2CameraProxy::setFmtFromConfig(const StreamConfiguration &streamConfig)
{
	const Size &size = streamConfig.size;

	v4l2PixFormat_.width        = size.width;
	v4l2PixFormat_.height       = size.height;
	v4l2PixFormat_.pixelformat  = V4L2PixelFormat::fromPixelFormat(streamConfig.pixelFormat)[0];
	v4l2PixFormat_.field        = V4L2_FIELD_NONE;
	v4l2PixFormat_.bytesperline = streamConfig.stride;
	v4l2PixFormat_.sizeimage    = streamConfig.frameSize;
	v4l2PixFormat_.colorspace   = V4L2_COLORSPACE_SRGB;
	v4l2PixFormat_.priv         = V4L2_PIX_FMT_PRIV_MAGIC;
	v4l2PixFormat_.ycbcr_enc    = V4L2_YCBCR_ENC_DEFAULT;
	v4l2PixFormat_.quantization = V4L2_QUANTIZATION_DEFAULT;
	v4l2PixFormat_.xfer_func    = V4L2_XFER_FUNC_DEFAULT;

	sizeimage_ = streamConfig.frameSize;
}

void V4L2CameraProxy::querycap(std::shared_ptr<Camera> camera)
{
	std::string driver = "libcamera";
	std::string bus_info = driver + ":" + std::to_string(index_);

	utils::strlcpy(reinterpret_cast<char *>(capabilities_.driver), driver.c_str(),
		       sizeof(capabilities_.driver));
	utils::strlcpy(reinterpret_cast<char *>(capabilities_.card), camera->id().c_str(),
		       sizeof(capabilities_.card));
	utils::strlcpy(reinterpret_cast<char *>(capabilities_.bus_info), bus_info.c_str(),
		       sizeof(capabilities_.bus_info));
	/* \todo Put this in a header/config somewhere. */
	capabilities_.version = KERNEL_VERSION(5, 2, 0);
	capabilities_.device_caps = V4L2_CAP_VIDEO_CAPTURE
				  | V4L2_CAP_STREAMING
				  | V4L2_CAP_EXT_PIX_FORMAT;
	capabilities_.capabilities = capabilities_.device_caps
				   | V4L2_CAP_DEVICE_CAPS;
	memset(capabilities_.reserved, 0, sizeof(capabilities_.reserved));
}

void V4L2CameraProxy::updateBuffers()
{
	std::vector<V4L2Camera::Buffer> completedBuffers = vcam_->completedBuffers();
	for (const V4L2Camera::Buffer &buffer : completedBuffers) {
		const FrameMetadata &fmd = buffer.data_;
		struct v4l2_buffer &buf = buffers_[buffer.index_];

		switch (fmd.status) {
		case FrameMetadata::FrameSuccess:
			buf.bytesused = std::accumulate(fmd.planes().begin(),
							fmd.planes().end(), 0,
							[](unsigned int total, const auto &plane) {
								return total + plane.bytesused;
							});
			buf.field = V4L2_FIELD_NONE;
			buf.timestamp.tv_sec = fmd.timestamp / 1000000000;
			buf.timestamp.tv_usec = (fmd.timestamp / 1000) % 1000000;
			buf.sequence = fmd.sequence;

			buf.flags |= V4L2_BUF_FLAG_DONE;
			break;
		case FrameMetadata::FrameError:
			buf.flags |= V4L2_BUF_FLAG_ERROR;
			break;
		default:
			break;
		}
	}
}

int V4L2CameraProxy::vidioc_querycap(V4L2CameraFile *file, struct v4l2_capability *arg)
{
	LOG(V4L2Compat, Debug)
		<< "[" << file->description() << "] " << __func__ << "()";

	*arg = capabilities_;

	return 0;
}

int V4L2CameraProxy::vidioc_enum_framesizes(V4L2CameraFile *file, struct v4l2_frmsizeenum *arg)
{
	LOG(V4L2Compat, Debug)
		<< "[" << file->description() << "] " << __func__ << "()";

	V4L2PixelFormat v4l2Format = V4L2PixelFormat(arg->pixel_format);
	PixelFormat format = v4l2Format.toPixelFormat();
	/*
	 * \todo This might need to be expanded as few pipeline handlers
	 * report StreamFormats.
	 */
	const std::vector<Size> &frameSizes = streamConfig_.formats().sizes(format);

	if (arg->index >= frameSizes.size())
		return -EINVAL;

	arg->type = V4L2_FRMSIZE_TYPE_DISCRETE;
	arg->discrete.width = frameSizes[arg->index].width;
	arg->discrete.height = frameSizes[arg->index].height;
	memset(arg->reserved, 0, sizeof(arg->reserved));

	return 0;
}

int V4L2CameraProxy::vidioc_enum_fmt(V4L2CameraFile *file, struct v4l2_fmtdesc *arg)
{
	LOG(V4L2Compat, Debug)
		<< "[" << file->description() << "] " << __func__ << "()";

	if (!validateBufferType(arg->type) ||
	    arg->index >= streamConfig_.formats().pixelformats().size())
		return -EINVAL;

	PixelFormat format = streamConfig_.formats().pixelformats()[arg->index];
	V4L2PixelFormat v4l2Format = V4L2PixelFormat::fromPixelFormat(format)[0];

	arg->flags = format == formats::MJPEG ? V4L2_FMT_FLAG_COMPRESSED : 0;
	utils::strlcpy(reinterpret_cast<char *>(arg->description),
		       v4l2Format.description(), sizeof(arg->description));
	arg->pixelformat = v4l2Format;

	memset(arg->reserved, 0, sizeof(arg->reserved));

	return 0;
}

int V4L2CameraProxy::vidioc_g_fmt(V4L2CameraFile *file, struct v4l2_format *arg)
{
	LOG(V4L2Compat, Debug)
		<< "[" << file->description() << "] " << __func__ << "()";

	if (!validateBufferType(arg->type))
		return -EINVAL;

	memset(&arg->fmt, 0, sizeof(arg->fmt));
	arg->fmt.pix = v4l2PixFormat_;

	return 0;
}

int V4L2CameraProxy::tryFormat(struct v4l2_format *arg)
{
	V4L2PixelFormat v4l2Format = V4L2PixelFormat(arg->fmt.pix.pixelformat);
	PixelFormat format = v4l2Format.toPixelFormat();
	Size size(arg->fmt.pix.width, arg->fmt.pix.height);

	StreamConfiguration config;
	int ret = vcam_->validateConfiguration(format, size, &config);
	if (ret < 0) {
		LOG(V4L2Compat, Error)
			<< "Failed to negotiate a valid format: "
			<< format;
		return -EINVAL;
	}

	arg->fmt.pix.width        = config.size.width;
	arg->fmt.pix.height       = config.size.height;
	arg->fmt.pix.pixelformat  = V4L2PixelFormat::fromPixelFormat(config.pixelFormat)[0];
	arg->fmt.pix.field        = V4L2_FIELD_NONE;
	arg->fmt.pix.bytesperline = config.stride;
	arg->fmt.pix.sizeimage    = config.frameSize;
	arg->fmt.pix.colorspace   = V4L2_COLORSPACE_SRGB;
	arg->fmt.pix.priv         = V4L2_PIX_FMT_PRIV_MAGIC;
	arg->fmt.pix.ycbcr_enc    = V4L2_YCBCR_ENC_DEFAULT;
	arg->fmt.pix.quantization = V4L2_QUANTIZATION_DEFAULT;
	arg->fmt.pix.xfer_func    = V4L2_XFER_FUNC_DEFAULT;

	return 0;
}

int V4L2CameraProxy::vidioc_s_fmt(V4L2CameraFile *file, struct v4l2_format *arg)
{
	LOG(V4L2Compat, Debug)
		<< "[" << file->description() << "] " << __func__ << "()";

	if (!validateBufferType(arg->type))
		return -EINVAL;

	if (file->priority() < maxPriority())
		return -EBUSY;

	int ret = acquire(file);
	if (ret < 0)
		return ret;

	ret = tryFormat(arg);
	if (ret < 0)
		return ret;

	Size size(arg->fmt.pix.width, arg->fmt.pix.height);
	V4L2PixelFormat v4l2Format = V4L2PixelFormat(arg->fmt.pix.pixelformat);
	ret = vcam_->configure(&streamConfig_, size, v4l2Format.toPixelFormat(),
			       bufferCount_);
	if (ret < 0)
		return -EINVAL;

	setFmtFromConfig(streamConfig_);

	return 0;
}

int V4L2CameraProxy::vidioc_try_fmt(V4L2CameraFile *file, struct v4l2_format *arg)
{
	LOG(V4L2Compat, Debug)
		<< "[" << file->description() << "] " << __func__ << "()";

	if (!validateBufferType(arg->type))
		return -EINVAL;

	int ret = tryFormat(arg);
	if (ret < 0)
		return ret;

	return 0;
}

enum v4l2_priority V4L2CameraProxy::maxPriority()
{
	auto max = std::max_element(files_.begin(), files_.end(),
				    [](const V4L2CameraFile *a, const V4L2CameraFile *b) {
					    return a->priority() < b->priority();
				    });
	return max != files_.end() ? (*max)->priority() : V4L2_PRIORITY_UNSET;
}

int V4L2CameraProxy::vidioc_g_priority(V4L2CameraFile *file, enum v4l2_priority *arg)
{
	LOG(V4L2Compat, Debug)
		<< "[" << file->description() << "] " << __func__ << "()";

	*arg = maxPriority();

	return 0;
}

int V4L2CameraProxy::vidioc_s_priority(V4L2CameraFile *file, enum v4l2_priority *arg)
{
	LOG(V4L2Compat, Debug)
		<< "[" << file->description() << "] " << __func__ << "()";

	if (*arg > V4L2_PRIORITY_RECORD)
		return -EINVAL;

	if (file->priority() < maxPriority())
		return -EBUSY;

	file->setPriority(*arg);

	return 0;
}

int V4L2CameraProxy::vidioc_enuminput(V4L2CameraFile *file, struct v4l2_input *arg)
{
	LOG(V4L2Compat, Debug)
		<< "[" << file->description() << "] " << __func__ << "()";

	if (arg->index != 0)
		return -EINVAL;

	memset(arg, 0, sizeof(*arg));

	utils::strlcpy(reinterpret_cast<char *>(arg->name),
		       reinterpret_cast<char *>(capabilities_.card),
		       sizeof(arg->name));
	arg->type = V4L2_INPUT_TYPE_CAMERA;

	return 0;
}

int V4L2CameraProxy::vidioc_g_input(V4L2CameraFile *file, int *arg)
{
	LOG(V4L2Compat, Debug)
		<< "[" << file->description() << "] " << __func__ << "()";

	*arg = 0;

	return 0;
}

int V4L2CameraProxy::vidioc_s_input(V4L2CameraFile *file, int *arg)
{
	LOG(V4L2Compat, Debug)
		<< "[" << file->description() << "] " << __func__ << "()";

	if (*arg != 0)
		return -EINVAL;

	return 0;
}

void V4L2CameraProxy::freeBuffers()
{
	vcam_->freeBuffers();
	buffers_.clear();
	bufferCount_ = 0;
}

int V4L2CameraProxy::vidioc_reqbufs(V4L2CameraFile *file, struct v4l2_requestbuffers *arg)
{
	LOG(V4L2Compat, Debug)
		<< "[" << file->description() << "] " << __func__ << "()";

	if (!validateBufferType(arg->type) ||
	    !validateMemoryType(arg->memory))
		return -EINVAL;

	LOG(V4L2Compat, Debug) << arg->count << " buffers requested ";

	if (file->priority() < maxPriority())
		return -EBUSY;

	if (!hasOwnership(file) && owner_)
		return -EBUSY;

	arg->capabilities = V4L2_BUF_CAP_SUPPORTS_MMAP;
	arg->flags = 0;
	memset(arg->reserved, 0, sizeof(arg->reserved));

	if (arg->count == 0) {
		/* \todo Add buffer orphaning support */
		if (!mmaps_.empty())
			return -EBUSY;

		if (vcam_->isRunning())
			return -EBUSY;

		freeBuffers();
		release(file);

		return 0;
	}

	if (bufferCount_ > 0)
		freeBuffers();

	Size size(v4l2PixFormat_.width, v4l2PixFormat_.height);
	V4L2PixelFormat v4l2Format = V4L2PixelFormat(v4l2PixFormat_.pixelformat);
	int ret = vcam_->configure(&streamConfig_, size,
				   v4l2Format.toPixelFormat(), arg->count);
	if (ret < 0)
		return -EINVAL;

	setFmtFromConfig(streamConfig_);

	arg->count = streamConfig_.bufferCount;
	bufferCount_ = arg->count;

	ret = vcam_->allocBuffers(arg->count);
	if (ret < 0) {
		arg->count = 0;
		return ret;
	}

	buffers_.resize(arg->count);
	for (unsigned int i = 0; i < arg->count; i++) {
		struct v4l2_buffer buf = {};
		buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
		buf.length = v4l2PixFormat_.sizeimage;
		buf.memory = V4L2_MEMORY_MMAP;
		buf.m.offset = i * v4l2PixFormat_.sizeimage;
		buf.index = i;
		buf.flags = V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC;

		buffers_[i] = buf;
	}

	LOG(V4L2Compat, Debug) << "Allocated " << arg->count << " buffers";

	acquire(file);

	return 0;
}

int V4L2CameraProxy::vidioc_querybuf(V4L2CameraFile *file, struct v4l2_buffer *arg)
{
	LOG(V4L2Compat, Debug)
		<< "[" << file->description() << "] " << __func__ << "()";

	if (arg->index >= bufferCount_)
		return -EINVAL;

	if (!validateBufferType(arg->type) ||
	    arg->index >= bufferCount_)
		return -EINVAL;

	updateBuffers();

	*arg = buffers_[arg->index];

	return 0;
}

int V4L2CameraProxy::vidioc_prepare_buf(V4L2CameraFile *file, struct v4l2_buffer *arg)
{
	LOG(V4L2Compat, Debug)
		<< "[" << file->description() << "] " << __func__
		<< "(index=" << arg->index << ")";

	if (!hasOwnership(file))
		return -EBUSY;

	if (arg->index >= bufferCount_)
		return -EINVAL;

	if (arg->flags & V4L2_BUF_FLAG_REQUEST_FD)
		return -EINVAL;

	if (!validateBufferType(arg->type) ||
	    !validateMemoryType(arg->memory))
		return -EINVAL;

	struct v4l2_buffer &buffer = buffers_[arg->index];

	if (buffer.flags & V4L2_BUF_FLAG_QUEUED ||
	    buffer.flags & V4L2_BUF_FLAG_PREPARED)
		return -EINVAL;

	buffer.flags |= V4L2_BUF_FLAG_PREPARED;

	arg->flags = buffer.flags;

	return 0;
}

int V4L2CameraProxy::vidioc_qbuf(V4L2CameraFile *file, struct v4l2_buffer *arg)
{
	LOG(V4L2Compat, Debug)
		<< "[" << file->description() << "] " << __func__
		<< "(index=" << arg->index << ")";

	if (arg->index >= bufferCount_)
		return -EINVAL;

	if (buffers_[arg->index].flags & V4L2_BUF_FLAG_QUEUED)
		return -EINVAL;

	if (!hasOwnership(file))
		return -EBUSY;

	if (!validateBufferType(arg->type) ||
	    !validateMemoryType(arg->memory) ||
	    arg->index >= bufferCount_)
		return -EINVAL;

	int ret = vcam_->qbuf(arg->index);
	if (ret < 0)
		return ret;

	buffers_[arg->index].flags |= V4L2_BUF_FLAG_QUEUED;

	arg->flags = buffers_[arg->index].flags;

	return ret;
}

int V4L2CameraProxy::vidioc_dqbuf(V4L2CameraFile *file, struct v4l2_buffer *arg,
				  Mutex *lock)
{
	LOG(V4L2Compat, Debug)
		<< "[" << file->description() << "] " << __func__ << "()";

	if (arg->index >= bufferCount_)
		return -EINVAL;

	if (!hasOwnership(file))
		return -EBUSY;

	if (!vcam_->isRunning())
		return -EINVAL;

	if (!validateBufferType(arg->type) ||
	    !validateMemoryType(arg->memory))
		return -EINVAL;

	if (!file->nonBlocking()) {
		lock->unlock();
		vcam_->waitForBufferAvailable();
		lock->lock();
	} else if (!vcam_->isBufferAvailable())
		return -EAGAIN;

	/*
	 * We need to check here again in case stream was turned off while we
	 * were blocked on waitForBufferAvailable().
	 */
	if (!vcam_->isRunning())
		return -EINVAL;

	updateBuffers();

	struct v4l2_buffer &buf = buffers_[currentBuf_];

	buf.flags &= ~(V4L2_BUF_FLAG_QUEUED | V4L2_BUF_FLAG_DONE | V4L2_BUF_FLAG_PREPARED);
	buf.length = sizeimage_;
	*arg = buf;

	currentBuf_ = (currentBuf_ + 1) % bufferCount_;

	uint64_t data;
	int ret = ::read(file->efd(), &data, sizeof(data));
	if (ret != sizeof(data))
		LOG(V4L2Compat, Error) << "Failed to clear eventfd POLLIN";

	return 0;
}

int V4L2CameraProxy::vidioc_expbuf(V4L2CameraFile *file, struct v4l2_exportbuffer *arg)
{
	LOG(V4L2Compat, Debug)
		<< "[" << file->description() << "] " << __func__ << "()";

	if (!hasOwnership(file))
		return -EBUSY;

	/* \todo Verify that the memory type is MMAP when adding DMABUF support */
	if (!validateBufferType(arg->type))
		return -EINVAL;

	if (arg->index >= bufferCount_)
		return -EINVAL;

	if (arg->flags & ~(O_CLOEXEC | O_ACCMODE))
		return -EINVAL;

	memset(arg->reserved, 0, sizeof(arg->reserved));

	/* \todo honor the O_ACCMODE flags passed to this function */
	arg->fd = fcntl(vcam_->getBufferFd(arg->index),
			arg->flags & O_CLOEXEC ? F_DUPFD_CLOEXEC : F_DUPFD, 0);

	return 0;
}

int V4L2CameraProxy::vidioc_streamon(V4L2CameraFile *file, int *arg)
{
	LOG(V4L2Compat, Debug)
		<< "[" << file->description() << "] " << __func__ << "()";

	if (bufferCount_ == 0)
		return -EINVAL;

	if (!validateBufferType(*arg))
		return -EINVAL;

	if (file->priority() < maxPriority())
		return -EBUSY;

	if (!hasOwnership(file))
		return -EBUSY;

	if (vcam_->isRunning())
		return 0;

	currentBuf_ = 0;

	return vcam_->streamOn();
}

int V4L2CameraProxy::vidioc_streamoff(V4L2CameraFile *file, int *arg)
{
	LOG(V4L2Compat, Debug)
		<< "[" << file->description() << "] " << __func__ << "()";

	if (!validateBufferType(*arg))
		return -EINVAL;

	if (file->priority() < maxPriority())
		return -EBUSY;

	if (!hasOwnership(file) && owner_)
		return -EBUSY;

	int ret = vcam_->streamOff();

	for (struct v4l2_buffer &buf : buffers_)
		buf.flags &= ~(V4L2_BUF_FLAG_QUEUED | V4L2_BUF_FLAG_DONE);

	return ret;
}

int V4L2CameraProxy::vidioc_s_parm(V4L2CameraFile *file, struct v4l2_streamparm *arg)
{
	LOG(V4L2Compat, Debug)
		<< "[" << file->description() << "] " << __func__ << "()";

	if (!validateBufferType(arg->type))
		return -EINVAL;

	struct v4l2_fract *timeperframe = &arg->parm.capture.timeperframe;
	utils::Duration frameDuration = 1.0s * timeperframe->numerator / timeperframe->denominator;

	int64_t uDuration = frameDuration.get<std::micro>();
	vcam_->controls().set(controls::FrameDurationLimits, { uDuration, uDuration });

	return 0;
}

const std::set<unsigned long> V4L2CameraProxy::supportedIoctls_ = {
	VIDIOC_QUERYCAP,
	VIDIOC_ENUM_FRAMESIZES,
	VIDIOC_ENUM_FMT,
	VIDIOC_G_FMT,
	VIDIOC_S_FMT,
	VIDIOC_TRY_FMT,
	VIDIOC_G_PRIORITY,
	VIDIOC_S_PRIORITY,
	VIDIOC_ENUMINPUT,
	VIDIOC_G_INPUT,
	VIDIOC_S_INPUT,
	VIDIOC_REQBUFS,
	VIDIOC_QUERYBUF,
	VIDIOC_PREPARE_BUF,
	VIDIOC_QBUF,
	VIDIOC_DQBUF,
	VIDIOC_EXPBUF,
	VIDIOC_STREAMON,
	VIDIOC_STREAMOFF,
	VIDIOC_S_PARM,
};

int V4L2CameraProxy::ioctl(V4L2CameraFile *file, unsigned long longRequest, void *arg)
{
	MutexLocker locker(proxyMutex_);

	/*
	 * The Linux Kernel only processes 32 bits of an IOCTL.
	 *
	 * Prevent unexpected sign-extensions that could occur if applications
	 * use a signed int for the ioctl request, which would sign-extend to
	 * an incorrect value for unsigned longs on 64 bit architectures by
	 * explicitly casting as an unsigned int here.
	 */
	unsigned int request = longRequest;

	if (!arg && (_IOC_DIR(request) & _IOC_WRITE)) {
		errno = EFAULT;
		return -1;
	}

	if (supportedIoctls_.find(request) == supportedIoctls_.end()) {
		errno = ENOTTY;
		return -1;
	}

	if (!arg && (_IOC_DIR(request) & _IOC_READ)) {
		errno = EFAULT;
		return -1;
	}

	int ret;
	switch (request) {
	case VIDIOC_QUERYCAP:
		ret = vidioc_querycap(file, static_cast<struct v4l2_capability *>(arg));
		break;
	case VIDIOC_ENUM_FRAMESIZES:
		ret = vidioc_enum_framesizes(file, static_cast<struct v4l2_frmsizeenum *>(arg));
		break;
	case VIDIOC_ENUM_FMT:
		ret = vidioc_enum_fmt(file, static_cast<struct v4l2_fmtdesc *>(arg));
		break;
	case VIDIOC_G_FMT:
		ret = vidioc_g_fmt(file, static_cast<struct v4l2_format *>(arg));
		break;
	case VIDIOC_S_FMT:
		ret = vidioc_s_fmt(file, static_cast<struct v4l2_format *>(arg));
		break;
	case VIDIOC_TRY_FMT:
		ret = vidioc_try_fmt(file, static_cast<struct v4l2_format *>(arg));
		break;
	case VIDIOC_G_PRIORITY:
		ret = vidioc_g_priority(file, static_cast<enum v4l2_priority *>(arg));
		break;
	case VIDIOC_S_PRIORITY:
		ret = vidioc_s_priority(file, static_cast<enum v4l2_priority *>(arg));
		break;
	case VIDIOC_ENUMINPUT:
		ret = vidioc_enuminput(file, static_cast<struct v4l2_input *>(arg));
		break;
	case VIDIOC_G_INPUT:
		ret = vidioc_g_input(file, static_cast<int *>(arg));
		break;
	case VIDIOC_S_INPUT:
		ret = vidioc_s_input(file, static_cast<int *>(arg));
		break;
	case VIDIOC_REQBUFS:
		ret = vidioc_reqbufs(file, static_cast<struct v4l2_requestbuffers *>(arg));
		break;
	case VIDIOC_QUERYBUF:
		ret = vidioc_querybuf(file, static_cast<struct v4l2_buffer *>(arg));
		break;
	case VIDIOC_QBUF:
		ret = vidioc_qbuf(file, static_cast<struct v4l2_buffer *>(arg));
		break;
	case VIDIOC_DQBUF:
		ret = vidioc_dqbuf(file, static_cast<struct v4l2_buffer *>(arg), &proxyMutex_);
		break;
	case VIDIOC_EXPBUF:
		ret = vidioc_expbuf(file, static_cast<struct v4l2_exportbuffer *>(arg));
		break;
	case VIDIOC_STREAMON:
		ret = vidioc_streamon(file, static_cast<int *>(arg));
		break;
	case VIDIOC_STREAMOFF:
		ret = vidioc_streamoff(file, static_cast<int *>(arg));
		break;
	case VIDIOC_S_PARM:
		ret = vidioc_s_parm(file, static_cast<struct v4l2_streamparm *>(arg));
		break;
	default:
		ret = -ENOTTY;
		break;
	}

	if (ret < 0) {
		errno = -ret;
		return -1;
	}

	return ret;
}

bool V4L2CameraProxy::hasOwnership(V4L2CameraFile *file)
{
	return owner_ == file;
}

/**
 * \brief Acquire exclusive ownership of the V4L2Camera
 *
 * \return Zero on success or if already acquired, and negative error on
 * failure.
 *
 * This is sufficient for poll()ing for buffers. Events, however, are signaled
 * on the file level, so all fds must be signaled. poll()ing from a different
 * fd than the one that locks the device is a corner case, and is currently not
 * supported.
 */
int V4L2CameraProxy::acquire(V4L2CameraFile *file)
{
	if (owner_ == file)
		return 0;

	if (owner_)
		return -EBUSY;

	vcam_->bind(file->efd());

	owner_ = file;

	return 0;
}

void V4L2CameraProxy::release(V4L2CameraFile *file)
{
	if (owner_ != file)
		return;

	vcam_->unbind();

	owner_ = nullptr;
}