/* 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/camera.h> #include <libcamera/camera_manager.h> #include "libcamera/internal/log.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, "openat"); get_symbol(fops_.dup, "dup"); get_symbol(fops_.close, "close"); get_symbol(fops_.ioctl, "ioctl"); get_symbol(fops_.mmap, "mmap"); get_symbol(fops_.munmap, "munmap"); } V4L2CompatManager::~V4L2CompatManager() { devices_.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. */ unsigned int index = 0; for (auto &camera : cm_->cameras()) { V4L2CameraProxy *proxy = new V4L2CameraProxy(index, camera); proxies_.emplace_back(proxy); ++index; } return 0; } V4L2CompatManager *V4L2CompatManager::instance() { static V4L2CompatManager instance; return &instance; } V4L2CameraProxy *V4L2CompatManager::getProxy(int fd) { auto device = devices_.find(fd); if (device == devices_.end()) return nullptr; return device->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; unsigned int index = 0; for (auto &camera : cm_->cameras()) { if (camera == target) return index; ++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, Info) << "No camera found for " << path; return fd; } fops_.close(fd); unsigned int camera_index = static_cast<unsigned int>(ret); V4L2CameraProxy *proxy = proxies_[camera_index].get(); ret = proxy->open(oflag & O_NONBLOCK); if (ret < 0) return ret; int efd = eventfd(0, EFD_SEMAPHORE | ((oflag & O_CLOEXEC) ? EFD_CLOEXEC : 0) | ((oflag & O_NONBLOCK) ? EFD_NONBLOCK : 0)); if (efd < 0) { int err = errno; proxy->close(); errno = err; return efd; } proxy->bind(efd); devices_.emplace(efd, proxy); return efd; } int V4L2CompatManager::dup(int oldfd) { int newfd = fops_.dup(oldfd); if (newfd < 0) return newfd; auto device = devices_.find(oldfd); if (device != devices_.end()) { V4L2CameraProxy *proxy = device->second; devices_[newfd] = proxy; proxy->dup(); } return newfd; } int V4L2CompatManager::close(int fd) { V4L2CameraProxy *proxy = getProxy(fd); if (proxy) { proxy->close(); devices_.erase(fd); return 0; } return fops_.close(fd); } void *V4L2CompatManager::mmap(void *addr, size_t length, int prot, int flags, int fd, off_t offset) { V4L2CameraProxy *proxy = getProxy(fd); if (!proxy) return fops_.mmap(addr, length, prot, flags, fd, offset); void *map = proxy->mmap(addr, length, prot, flags, offset); if (map == MAP_FAILED) return map; mmaps_[map] = 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) { V4L2CameraProxy *proxy = getProxy(fd); if (!proxy) return fops_.ioctl(fd, request, arg); return proxy->ioctl(request, arg); }