/* 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 <dlfcn.h> #include <fcntl.h> #include <map> #include <stdarg.h> #include <string.h> #include <sys/eventfd.h> #include <sys/mman.h> #include <sys/stat.h> #include <sys/sysmacros.h> #include <sys/types.h> #include <unistd.h> #include <libcamera/base/log.h> #include <libcamera/base/utils.h> #include <libcamera/camera.h> #include <libcamera/camera_manager.h> #include "v4l2_camera_file.h" using namespace libcamera; LOG_DEFINE_CATEGORY(V4L2Compat) namespace { template<typename T> void get_symbol(T &func, const char *name) { func = reinterpret_cast<T>(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<V4L2CameraFile> 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<Camera> 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<V4L2CameraFile>(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<V4L2CameraFile> file = cameraFile(fd); if (!file) return fops_.mmap(addr, length, prot, flags, fd, offset); void *map = file->proxy()->mmap(addr, length, prot, flags, offset); if (map == MAP_FAILED) return map; /* * Map to V4L2CameraProxy directly to prevent adding more references * to V4L2CameraFile. */ mmaps_[map] = file->proxy(); return map; } int V4L2CompatManager::munmap(void *addr, size_t length) { auto device = mmaps_.find(addr); if (device == mmaps_.end()) return fops_.munmap(addr, length); V4L2CameraProxy *proxy = device->second; int ret = proxy->munmap(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<V4L2CameraFile> file = cameraFile(fd); if (!file) return fops_.ioctl(fd, request, arg); return file->proxy()->ioctl(file.get(), request, arg); }