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/* SPDX-License-Identifier: LGPL-2.1-or-later */
/*
* Copyright (C) 2018-2019, Google Inc.
*
* device_enumerator_udev.cpp - udev-based device enumerator
*/
#include "device_enumerator_udev.h"
#include <fcntl.h>
#include <libudev.h>
#include <string.h>
#include <sys/ioctl.h>
#include <sys/sysmacros.h>
#include <unistd.h>
#include <libcamera/event_notifier.h>
#include "log.h"
namespace libcamera {
LOG_DECLARE_CATEGORY(DeviceEnumerator)
DeviceEnumeratorUdev::DeviceEnumeratorUdev()
: udev_(nullptr)
{
}
DeviceEnumeratorUdev::~DeviceEnumeratorUdev()
{
delete notifier_;
if (monitor_)
udev_monitor_unref(monitor_);
if (udev_)
udev_unref(udev_);
}
int DeviceEnumeratorUdev::init()
{
int ret;
if (udev_)
return -EBUSY;
udev_ = udev_new();
if (!udev_)
return -ENODEV;
monitor_ = udev_monitor_new_from_netlink(udev_, "udev");
if (!monitor_)
return -ENODEV;
ret = udev_monitor_filter_add_match_subsystem_devtype(monitor_, "media",
nullptr);
if (ret < 0)
return ret;
return 0;
}
int DeviceEnumeratorUdev::enumerate()
{
struct udev_enumerate *udev_enum = nullptr;
struct udev_list_entry *ents, *ent;
int ret;
udev_enum = udev_enumerate_new(udev_);
if (!udev_enum)
return -ENOMEM;
ret = udev_enumerate_add_match_subsystem(udev_enum, "media");
if (ret < 0)
goto done;
ret = udev_enumerate_scan_devices(udev_enum);
if (ret < 0)
goto done;
ents = udev_enumerate_get_list_entry(udev_enum);
if (!ents)
goto done;
udev_list_entry_foreach(ent, ents) {
struct udev_device *dev;
const char *devnode;
const char *syspath = udev_list_entry_get_name(ent);
dev = udev_device_new_from_syspath(udev_, syspath);
if (!dev) {
LOG(DeviceEnumerator, Warning)
<< "Failed to get device for '"
<< syspath << "', skipping";
continue;
}
devnode = udev_device_get_devnode(dev);
if (!devnode) {
udev_device_unref(dev);
ret = -ENODEV;
goto done;
}
addDevice(devnode);
udev_device_unref(dev);
}
done:
udev_enumerate_unref(udev_enum);
if (ret < 0)
return ret;
ret = udev_monitor_enable_receiving(monitor_);
if (ret < 0)
return ret;
int fd = udev_monitor_get_fd(monitor_);
notifier_ = new EventNotifier(fd, EventNotifier::Read);
notifier_->activated.connect(this, &DeviceEnumeratorUdev::udevNotify);
return 0;
}
std::string DeviceEnumeratorUdev::lookupDeviceNode(int major, int minor)
{
struct udev_device *device;
const char *name;
dev_t devnum;
std::string deviceNode = std::string();
devnum = makedev(major, minor);
device = udev_device_new_from_devnum(udev_, 'c', devnum);
if (!device)
return std::string();
name = udev_device_get_devnode(device);
if (name)
deviceNode = name;
udev_device_unref(device);
return deviceNode;
}
void DeviceEnumeratorUdev::udevNotify(EventNotifier *notifier)
{
struct udev_device *dev = udev_monitor_receive_device(monitor_);
std::string action(udev_device_get_action(dev));
std::string deviceNode(udev_device_get_devnode(dev));
LOG(DeviceEnumerator, Debug)
<< action << " device " << udev_device_get_devnode(dev);
if (action == "add") {
addDevice(deviceNode);
} else if (action == "remove") {
removeDevice(deviceNode);
}
udev_device_unref(dev);
}
} /* namespace libcamera */
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