int device_wait_for_initialization(sd_device *device, const char *subsystem, sd_device **ret) {
_cleanup_(sd_device_monitor_unrefp) sd_device_monitor *monitor = NULL;
_cleanup_(sd_event_unrefp) sd_event *event = NULL;
struct DeviceMonitorData data = {};
int r;
assert(device);
assert(subsystem);
if (sd_device_get_is_initialized(device) > 0) {
if (ret)
*ret = sd_device_ref(device);
return 0;
}
assert_se(sd_device_get_sysname(device, &data.sysname) >= 0);
/* Wait until the device is initialized, so that we can get access to the ID_PATH property */
r = sd_event_new(&event);
if (r < 0)
return log_error_errno(r, "Failed to get default event: %m");
r = sd_device_monitor_new(&monitor);
if (r < 0)
return log_error_errno(r, "Failed to acquire monitor: %m");
r = sd_device_monitor_filter_add_match_subsystem_devtype(monitor, subsystem, NULL);
if (r < 0)
return log_error_errno(r, "Failed to add %s subsystem match to monitor: %m", subsystem);
r = sd_device_monitor_attach_event(monitor, event);
if (r < 0)
return log_error_errno(r, "Failed to attach event to device monitor: %m");
r = sd_device_monitor_start(monitor, device_monitor_handler, &data);
if (r < 0)
return log_error_errno(r, "Failed to start device monitor: %m");
/* Check again, maybe things changed. Udev will re-read the db if the device wasn't initialized
* yet. */
if (sd_device_get_is_initialized(device) > 0) {
if (ret)
*ret = sd_device_ref(device);
return 0;
}
r = sd_event_loop(event);
if (r < 0)
return log_error_errno(r, "Event loop failed: %m");
if (ret)
*ret = TAKE_PTR(data.device);
return 0;
}
/**
* udev_device_get_sysname:
* @udev_device: udev device
*
* Get the kernel device name in /sys.
*
* Returns: the name string of the device device
**/
_public_ const char *udev_device_get_sysname(struct udev_device *udev_device)
{
const char *sysname;
int r;
assert_return_errno(udev_device, NULL, EINVAL);
r = sd_device_get_sysname(udev_device->device, &sysname);
if (r < 0) {
errno = -r;
return NULL;
}
return sysname;
}
static int device_monitor_handler(sd_device_monitor *monitor, sd_device *device, void *userdata) {
struct DeviceMonitorData *data = userdata;
const char *sysname;
assert(device);
assert(data);
assert(data->sysname);
assert(!data->device);
if (sd_device_get_sysname(device, &sysname) >= 0 && streq(sysname, data->sysname)) {
data->device = sd_device_ref(device);
return sd_event_exit(sd_device_monitor_get_event(monitor), 0);
}
return 0;
}
