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;
}
return log_error_errno(r, "Failed to attach event: %m");
HASHMAP_FOREACH_KEY(devtype, subsystem, arg_subsystem_filter, i) {
r = sd_device_monitor_filter_add_match_subsystem_devtype(monitor, subsystem, devtype);
if (r < 0)
return log_error_errno(r, "Failed to apply subsystem filter '%s%s%s': %m",
subsystem, devtype ? "/" : "", strempty(devtype));
}
SET_FOREACH(tag, arg_tag_filter, i) {
r = sd_device_monitor_filter_add_match_tag(monitor, tag);
if (r < 0)
return log_error_errno(r, "Failed to apply tag filter '%s': %m", tag);
}
r = sd_device_monitor_start(monitor, device_monitor_handler, INT_TO_PTR(sender));
if (r < 0)
return log_error_errno(r, "Failed to start device monitor: %m");
(void) sd_event_source_set_description(sd_device_monitor_get_event_source(monitor),
sender == MONITOR_GROUP_UDEV ? "device-monitor-udev" : "device-monitor-kernel");
*ret = TAKE_PTR(monitor);
return 0;
}
static int help(void) {
printf("%s monitor [OPTIONS]\n\n"
"Listen to kernel and udev events.\n\n"
" -h --help Show this help\n"
" -V --version Show package version\n"
