static int find_device(
const struct rfkill_event *event,
sd_device **ret) {
_cleanup_(sd_device_unrefp) sd_device *device = NULL;
_cleanup_free_ char *sysname = NULL;
const char *name;
int r;
assert(event);
assert(ret);
if (asprintf(&sysname, "rfkill%i", event->idx) < 0)
return log_oom();
r = sd_device_new_from_subsystem_sysname(&device, "rfkill", sysname);
if (r < 0)
return log_full_errno(IN_SET(r, -ENOENT, -ENXIO, -ENODEV) ? LOG_DEBUG : LOG_ERR, r,
"Failed to open device '%s': %m", sysname);
r = sd_device_get_sysattr_value(device, "name", &name);
if (r < 0)
return log_debug_errno(r, "Device has no name, ignoring: %m");
log_debug("Operating on rfkill device '%s'.", name);
*ret = TAKE_PTR(device);
return 0;
}
/* handle "[<SUBSYSTEM>/<KERNEL>]<attribute>" format */
int util_resolve_subsys_kernel(const char *string, char *result, size_t maxsize, bool read_value) {
char temp[UTIL_PATH_SIZE], *subsys, *sysname, *attr;
_cleanup_(sd_device_unrefp) sd_device *dev = NULL;
const char *val;
int r;
if (string[0] != '[')
return -EINVAL;
strscpy(temp, sizeof(temp), string);
subsys = &temp[1];
sysname = strchr(subsys, '/');
if (!sysname)
return -EINVAL;
sysname[0] = '\0';
sysname = &sysname[1];
attr = strchr(sysname, ']');
if (!attr)
return -EINVAL;
attr[0] = '\0';
attr = &attr[1];
if (attr[0] == '/')
attr = &attr[1];
if (attr[0] == '\0')
attr = NULL;
if (read_value && !attr)
return -EINVAL;
r = sd_device_new_from_subsystem_sysname(&dev, subsys, sysname);
if (r < 0)
return r;
if (read_value) {
r = sd_device_get_sysattr_value(dev, attr, &val);
if (r < 0 && r != -ENOENT)
return r;
if (r == -ENOENT)
result[0] = '\0';
else
strscpy(result, maxsize, val);
log_debug("value '[%s/%s]%s' is '%s'", subsys, sysname, attr, result);
} else {
r = sd_device_get_syspath(dev, &val);
if (r < 0)
return r;
strscpyl(result, maxsize, val, attr ? "/" : NULL, attr ?: NULL, NULL);
log_debug("path '[%s/%s]%s' is '%s'", subsys, sysname, strempty(attr), result);
}
return 0;
}
/**
* udev_device_new_from_subsystem_sysname:
* @udev: udev library context
* @subsystem: the subsystem of the device
* @sysname: the name of the device
*
* Create new udev device, and fill in information from the sys device
* and the udev database entry. The device is looked up by the subsystem
* and name string of the device, like "mem" / "zero", or "block" / "sda".
*
* The initial refcount is 1, and needs to be decremented to
* release the resources of the udev device.
*
* Returns: a new udev device, or #NULL, if it does not exist
**/
_public_ struct udev_device *udev_device_new_from_subsystem_sysname(struct udev *udev, const char *subsystem, const char *sysname)
{
struct udev_device *udev_device;
int r;
udev_device = udev_device_new(udev);
if (!udev_device)
return NULL;
r = sd_device_new_from_subsystem_sysname(&udev_device->device, subsystem, sysname);
if (r < 0) {
errno = -r;
udev_device_unref(udev_device);
return NULL;
}
return udev_device;
}
