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/* SPDX-License-Identifier: LGPL-2.1-or-later */
/*
 * Copyright (C) 2019, Google Inc.
 *
 * v4l2_compat.cpp - V4L2 compatibility layer
 */

#include "v4l2_compat_manager.h"

#include <errno.h>
#include <fcntl.h>
#include <stdarg.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <sys/types.h>

#define LIBCAMERA_PUBLIC __attribute__((visibility("default")))

using namespace libcamera;

#define extract_va_arg(type, arg, last)	\
{					\
	va_list ap;			\
	va_start(ap, last);		\
	arg = va_arg(ap, type);		\
	va_end(ap);			\
}

extern "C" {

LIBCAMERA_PUBLIC int open(const char *path, int oflag, ...)
{
	mode_t mode = 0;
	if (oflag & O_CREAT || oflag & O_TMPFILE)
		extract_va_arg(mode_t, mode, oflag);

	return V4L2CompatManager::instance()->openat(AT_FDCWD, path,
						     oflag, mode);
}

/* _FORTIFY_SOURCE redirects open to __open_2 */
LIBCAMERA_PUBLIC int __open_2(const char *path, int oflag)
{
	return open(path, oflag);
}

#ifndef open64
LIBCAMERA_PUBLIC int open64(const char *path, int oflag, ...)
{
	mode_t mode = 0;
	if (oflag & O_CREAT || oflag & O_TMPFILE)
		extract_va_arg(mode_t, mode, oflag);

	return V4L2CompatManager::instance()->openat(AT_FDCWD, path,
						     oflag | O_LARGEFILE, mode);
}

LIBCAMERA_PUBLIC int __open64_2(const char *path, int oflag)
{
	return open(path, oflag);
}
#endif

LIBCAMERA_PUBLIC int openat(int dirfd, const char *path, int oflag, ...)
{
	mode_t mode = 0;
	if (oflag & O_CREAT || oflag & O_TMPFILE)
		extract_va_arg(mode_t, mode, oflag);

	return V4L2CompatManager::instance()->openat(dirfd, path, oflag, mode);
}

LIBCAMERA_PUBLIC int __openat_2(int dirfd, const char *path, int oflag)
{
	return openat(dirfd, path, oflag);
}

#ifndef openat64
LIBCAMERA_PUBLIC int openat64(int dirfd, const char *path, int oflag, ...)
{
	mode_t mode = 0;
	if (oflag & O_CREAT || oflag & O_TMPFILE)
		extract_va_arg(mode_t, mode, oflag);

	return V4L2CompatManager::instance()->openat(dirfd, path,
						     oflag | O_LARGEFILE, mode);
}

LIBCAMERA_PUBLIC int __openat64_2(int dirfd, const char *path, int oflag)
{
	return openat(dirfd, path, oflag);
}
#endif

LIBCAMERA_PUBLIC int dup(int oldfd)
{
	return V4L2CompatManager::instance()->dup(oldfd);
}

LIBCAMERA_PUBLIC int close(int fd)
{
	return V4L2CompatManager::instance()->close(fd);
}

LIBCAMERA_PUBLIC void *mmap(void *addr, size_t length, int prot, int flags,
			    int fd, off_t offset)
{
	return V4L2CompatManager::instance()->mmap(addr, length, prot, flags,
						   fd, offset);
}

#ifndef mmap64
LIBCAMERA_PUBLIC void *mmap64(void *addr, size_t length, int prot, int flags,
			      int fd, off64_t offset)
{
	return V4L2CompatManager::instance()->mmap(addr, length, prot, flags,
						   fd, offset);
}
#endif

LIBCAMERA_PUBLIC int munmap(void *addr, size_t length)
{
	return V4L2CompatManager::instance()->munmap(addr, length);
}

LIBCAMERA_PUBLIC int ioctl(int fd, unsigned long request, ...)
{
	void *arg;
	extract_va_arg(void *, arg, request);

	return V4L2CompatManager::instance()->ioctl(fd, request, arg);
}

}
a::status * \brief Status of the frame * * The validity of other fields of the FrameMetadata structure depends on the * status value. */ /** * \var FrameMetadata::sequence * \brief Frame sequence number * * The sequence number is a monotonically increasing number assigned to the * frames captured by the stream. The value is increased by one for each frame. * Gaps in the sequence numbers indicate dropped frames. */ /** * \var FrameMetadata::timestamp * \brief Time when the frame was captured * * The timestamp is expressed as a number of nanoseconds relative to the system * clock since an unspecified time point. * * \todo Be more precise on what timestamps refer to. */ /** * \var FrameMetadata::planes * \brief Array of per-plane metadata */ /** * \class FrameBuffer * \brief Frame buffer data and its associated dynamic metadata * * The FrameBuffer class is the primary interface for applications, IPAs and * pipeline handlers to interact with frame memory. It contains all the static * and dynamic information to manage the whole life cycle of a frame capture, * from buffer creation to consumption. * * The static information describes the memory planes that make a frame. The * planes are specified when creating the FrameBuffer and are expressed as a set * of dmabuf file descriptors and length. * * The dynamic information is grouped in a FrameMetadata instance. It is updated * during the processing of a queued capture request, and is valid from the * completion of the buffer as signaled by Camera::bufferComplete() until the * FrameBuffer is either reused in a new request or deleted. * * The creator of a FrameBuffer (application, IPA or pipeline handler) may * associate to it an integer cookie for any private purpose. The cookie may be * set when creating the FrameBuffer, and updated at any time with setCookie(). * The cookie is transparent to the libcamera core and shall only be set by the * creator of the FrameBuffer. This mechanism supplements the Request cookie. */ /** * \struct FrameBuffer::Plane * \brief A memory region to store a single plane of a frame * * Planar pixel formats use multiple memory regions to store the different * colour components of a frame. The Plane structure describes such a memory * region by a dmabuf file descriptor and a length. A FrameBuffer then * contains one or multiple planes, depending on the pixel format of the * frames it is meant to store. * * To support DMA access, planes are associated with dmabuf objects represented * by FileDescriptor handles. The Plane class doesn't handle mapping of the * memory to the CPU, but applications and IPAs may use the dmabuf file * descriptors to map the plane memory with mmap() and access its contents. * * \todo Once we have a Kernel API which can express offsets within a plane * this structure shall be extended to contain this information. See commit * 83148ce8be55e for initial documentation of this feature. */ /** * \var FrameBuffer::Plane::fd * \brief The dmabuf file descriptor */ /** * \var FrameBuffer::Plane::length * \brief The plane length in bytes */ /** * \brief Construct a FrameBuffer with an array of planes * \param[in] planes The frame memory planes * \param[in] cookie Cookie */ FrameBuffer::FrameBuffer(const std::vector<Plane> &planes, unsigned int cookie) : planes_(planes), request_(nullptr), cookie_(cookie) { } /** * \fn FrameBuffer::planes() * \brief Retrieve the static plane descriptors * \return Array of plane descriptors */ /** * \fn FrameBuffer::request() * \brief Retrieve the request this buffer belongs to * * The intended callers of this method are buffer completion handlers that * need to associate a buffer to the request it belongs to. * * A FrameBuffer is associated to a request by Request::addBuffer() and the * association is valid until the buffer completes. The returned request * pointer is valid only during that interval. * * \return The Request the FrameBuffer belongs to, or nullptr if the buffer is * not associated with a request */ /** * \fn FrameBuffer::setRequest() * \brief Set the request this buffer belongs to * \param[in] request Request to set * * For buffers added to requests by applications, this method is called by * Request::addBuffer() or Request::reuse(). For buffers internal to pipeline * handlers, it is called by the pipeline handlers themselves. * * \todo Shall be hidden from applications with a d-pointer design. */ /** * \fn FrameBuffer::metadata() * \brief Retrieve the dynamic metadata * \return Dynamic metadata for the frame contained in the buffer */ /** * \fn FrameBuffer::cookie() * \brief Retrieve the cookie * * The cookie belongs to the creator of the FrameBuffer, which controls its * lifetime and value. * * \sa setCookie() * * \return The cookie */ /** * \fn FrameBuffer::setCookie() * \brief Set the cookie * \param[in] cookie Cookie to set * * The cookie belongs to the creator of the FrameBuffer. Its value may be * modified at any time with this method. Applications and IPAs shall not modify * the cookie value of buffers they haven't created themselves. The libcamera * core never modifies the buffer cookie. */ /** * \fn FrameBuffer::cancel() * \brief Marks the buffer as cancelled * * If a buffer is not used by a request, it shall be marked as cancelled to * indicate that the metadata is invalid. */ /** * \class MappedBuffer * \brief Provide an interface to support managing memory mapped buffers * * The MappedBuffer interface provides access to a set of MappedPlanes which * are available for access by the CPU. * * This class is not meant to be constructed directly, but instead derived * classes should be used to implement the correct mapping of a source buffer. * * This allows treating CPU accessible memory through a generic interface * regardless of whether it originates from a libcamera FrameBuffer or other * source. */ /** * \typedef MappedBuffer::Plane * \brief A mapped region of memory accessible to the CPU * * The MappedBuffer::Plane uses the Span interface to describe the mapped memory * region. */ /** * \brief Construct an empty MappedBuffer */ MappedBuffer::MappedBuffer() : error_(0) { } /** * \brief Move constructor, construct the MappedBuffer with the contents of \a * other using move semantics * \param[in] other The other MappedBuffer * * Moving a MappedBuffer moves the mappings contained in the \a other to the new * MappedBuffer and invalidates the \a other. * * No mappings are unmapped or destroyed in this process. */ MappedBuffer::MappedBuffer(MappedBuffer &&other) { *this = std::move(other); } /** * \brief Move assignment operator, replace the mappings with those of \a other * \param[in] other The other MappedBuffer * * Moving a MappedBuffer moves the mappings contained in the \a other to the new * MappedBuffer and invalidates the \a other. * * No mappings are unmapped or destroyed in this process. */ MappedBuffer &MappedBuffer::operator=(MappedBuffer &&other) { error_ = other.error_; maps_ = std::move(other.maps_); other.error_ = -ENOENT; return *this; } MappedBuffer::~MappedBuffer() { for (Plane &map : maps_) munmap(map.data(), map.size()); } /** * \fn MappedBuffer::isValid() * \brief Check if the MappedBuffer instance is valid * \return True if the MappedBuffer has valid mappings, false otherwise */ /** * \fn MappedBuffer::error() * \brief Retrieve the map error status * * This function retrieves the error status from the MappedBuffer. * The error status is a negative number as defined by errno.h. If * no error occurred, this function returns 0. * * \return The map error code */ /** * \fn MappedBuffer::maps() * \brief Retrieve the mapped planes * * This function retrieves the successfully mapped planes stored as a vector * of Span<uint8_t> to provide access to the mapped memory. * * \return A vector of the mapped planes */ /** * \var MappedBuffer::error_ * \brief Stores the error value if present * * MappedBuffer derived classes shall set this to a negative value as defined * by errno.h if an error occured during the mapping process. */ /** * \var MappedBuffer::maps_ * \brief Stores the internal mapped planes * * MappedBuffer derived classes shall store the mappings they create in this * vector which is parsed during destruct to unmap any memory mappings which * completed successfully. */ /** * \class MappedFrameBuffer * \brief Map a FrameBuffer using the MappedBuffer interface */ /** * \brief Map all planes of a FrameBuffer * \param[in] buffer FrameBuffer to be mapped * \param[in] flags Protection flags to apply to map * * Construct an object to map a frame buffer for CPU access. * The flags are passed directly to mmap and should be either PROT_READ, * PROT_WRITE, or a bitwise-or combination of both. */ MappedFrameBuffer::MappedFrameBuffer(const FrameBuffer *buffer, int flags) { maps_.reserve(buffer->planes().size()); for (const FrameBuffer::Plane &plane : buffer->planes()) { void *address = mmap(nullptr, plane.length, flags, MAP_SHARED, plane.fd.fd(), 0); if (address == MAP_FAILED) { error_ = -errno; LOG(Buffer, Error) << "Failed to mmap plane"; break; } maps_.emplace_back(static_cast<uint8_t *>(address), plane.length); } } } /* namespace libcamera */