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/* 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/base/utils.h>
#include "libcamera/internal/log.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, Info) << "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>(efd, oflag & O_NONBLOCK, proxy));
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);
}
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