/* SPDX-License-Identifier: LGPL-2.1-or-later */ /* * Copyright (C) 2019, Google Inc. * * v4l2_compat_manager.cpp - V4L2 compatibility manager */ #include "v4l2_compat_manager.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "v4l2_camera_file.h" using namespace libcamera; LOG_DEFINE_CATEGORY(V4L2Compat) namespace { template void get_symbol(T &func, const char *name) { func = reinterpret_cast(dlsym(RTLD_NEXT, name)); } } /* namespace */ V4L2CompatManager::V4L2CompatManager() : cm_(nullptr) { get_symbol(fops_.openat, "openat64"); get_symbol(fops_.dup, "dup"); get_symbol(fops_.close, "close"); get_symbol(fops_.ioctl, "ioctl"); get_symbol(fops_.mmap, "mmap64"); get_symbol(fops_.munmap, "munmap"); } V4L2CompatManager::~V4L2CompatManager() { files_.clear(); mmaps_.clear(); if (cm_) { proxies_.clear(); cm_->stop(); delete cm_; cm_ = nullptr; } } int V4L2CompatManager::start() { cm_ = new CameraManager(); int ret = cm_->start(); if (ret) { LOG(V4L2Compat, Error) << "Failed to start camera manager: " << strerror(-ret); delete cm_; cm_ = nullptr; return ret; } LOG(V4L2Compat, Debug) << "Started camera manager"; /* * For each Camera registered in the system, a V4L2CameraProxy gets * created here to wrap a camera device. */ auto cameras = cm_->cameras(); for (auto [index, camera] : utils::enumerate(cameras)) { V4L2CameraProxy *proxy = new V4L2CameraProxy(index, camera); proxies_.emplace_back(proxy); } return 0; } V4L2CompatManager *V4L2CompatManager::instance() { static V4L2CompatManager instance; return &instance; } std::shared_ptr V4L2CompatManager::cameraFile(int fd) { auto file = files_.find(fd); if (file == files_.end()) return nullptr; return file->second; } int V4L2CompatManager::getCameraIndex(int fd) { struct stat statbuf; int ret = fstat(fd, &statbuf); if (ret < 0) return -1; std::shared_ptr target = cm_->get(statbuf.st_rdev); if (!target) return -1; auto cameras = cm_->cameras(); for (auto [index, camera] : utils::enumerate(cameras)) { if (camera == target) return index; } return -1; } int V4L2CompatManager::openat(int dirfd, const char *path, int oflag, mode_t mode) { int fd = fops_.openat(dirfd, path, oflag, mode); if (fd < 0) return fd; struct stat statbuf; int ret = fstat(fd, &statbuf); if (ret < 0 || (statbuf.st_mode & S_IFMT) != S_IFCHR || major(statbuf.st_rdev) != 81) return fd; if (!cm_) start(); ret = getCameraIndex(fd); if (ret < 0) { LOG(V4L2Compat, Debug) << "No camera found for " << path; return fd; } fops_.close(fd); int efd = eventfd(0, EFD_SEMAPHORE | ((oflag & O_CLOEXEC) ? EFD_CLOEXEC : 0) | ((oflag & O_NONBLOCK) ? EFD_NONBLOCK : 0)); if (efd < 0) return efd; V4L2CameraProxy *proxy = proxies_[ret].get(); files_.emplace(efd, std::make_shared(dirfd, path, efd, oflag & O_NONBLOCK, proxy)); LOG(V4L2Compat, Debug) << "Opened " << path << " -> fd " << efd; return efd; } int V4L2CompatManager::dup(int oldfd) { int newfd = fops_.dup(oldfd); if (newfd < 0) return newfd; auto file = files_.find(oldfd); if (file != files_.end()) files_[newfd] = file->second; return newfd; } int V4L2CompatManager::close(int fd) { auto file = files_.find(fd); if (file != files_.end()) files_.erase(file); /* We still need to close the eventfd. */ return fops_.close(fd); } void *V4L2CompatManager::mmap(void *addr, size_t length, int prot, int flags, int fd, off64_t offset) { std::shared_ptr file = cameraFile(fd); if (!file) return fops_.mmap(addr, length, prot, flags, fd, offset); void *map = file->proxy()->mmap(file.get(), addr, length, prot, flags, offset); if (map == MAP_FAILED) return map; mmaps_[map] = file; return map; } int V4L2CompatManager::munmap(void *addr, size_t length) { auto device = mmaps_.find(addr); if (device == mmaps_.end()) return fops_.munmap(addr, length); V4L2CameraFile *file = device->second.get(); int ret = file->proxy()->munmap(file, addr, length); if (ret < 0) return ret; mmaps_.erase(device); return 0; } int V4L2CompatManager::ioctl(int fd, unsigned long request, void *arg) { std::shared_ptr file = cameraFile(fd); if (!file) return fops_.ioctl(fd, request, arg); return file->proxy()->ioctl(file.get(), request, arg); } ='n57' href='#n57'>57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243

/* SPDX-License-Identifier: LGPL-2.1-or-later */
/*
 * Copyright (C) 2021, Google Inc.
 *
 * Mapped Framebuffer support
 */

#include "libcamera/internal/mapped_framebuffer.h"

#include <algorithm>
#include <errno.h>
#include <map>
#include <sys/mman.h>
#include <unistd.h>

#include <libcamera/base/log.h>

/**
 * \file mapped_framebuffer.h
 * \brief Frame buffer memory mapping support
 */

namespace libcamera {

LOG_DECLARE_CATEGORY(Buffer)

/**
 * \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_;
	planes_ = std::move(other.planes_);
	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::planes()
 * \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::planes_
 * \brief Stores the internal mapped planes
 *
 * MappedBuffer derived classes shall store the mappings they create in this
 * vector which points the beginning of mapped plane addresses.
 */

/**
 * \var MappedBuffer::maps_
 * \brief Stores the mapped buffer
 *
 * 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
 */

/**
 * \enum MappedFrameBuffer::MapFlag
 * \brief Specify the mapping mode for the FrameBuffer
 * \var MappedFrameBuffer::Read
 * \brief Create a read-only mapping
 * \var MappedFrameBuffer::Write
 * \brief Create a write-only mapping
 * \var MappedFrameBuffer::ReadWrite
 * \brief Create a mapping that can be both read and written
 */

/**
 * \typedef MappedFrameBuffer::MapFlags
 * \brief A bitwise combination of MappedFrameBuffer::MapFlag values
 */

/**
 * \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 mapping can be
 * made as Read only, Write only or support Read and Write operations by setting
 * the MapFlag flags accordingly.
 */
MappedFrameBuffer::MappedFrameBuffer(const FrameBuffer *buffer, MapFlags flags)
{