/**
* udev_unref:
* @udev: udev library context
*
* Drop a reference of the udev library context. If the refcount
* reaches zero, the resources of the context will be released.
*
**/
void udev_unref(struct udev *udev)
{
if (udev == NULL)
return;
udev->refcount--;
if (udev->refcount > 0)
return;
udev_list_cleanup_entries(udev, &udev->properties_list);
free(udev->dev_path);
free(udev->sys_path);
free(udev->rules_path);
dbg(udev, "context %p released\n", udev);
free(udev);
}
static int update_link(struct udev_device *dev, const char *slink, int test)
{
struct udev *udev = udev_device_get_udev(dev);
struct udev_list_node dev_list;
struct udev_list_entry *dev_entry;
char target[UTIL_PATH_SIZE];
int count;
int priority = 0;
int rc = 0;
dbg(udev, "update symlink '%s' of '%s'\n", slink, udev_device_get_syspath(dev));
udev_list_init(&dev_list);
count = name_index_get_devices(udev, slink, &dev_list);
if (count > 1)
info(udev, "found %i devices with name '%s'\n", count, slink);
/* if we don't have a reference, delete it */
if (count <= 0) {
info(udev, "no reference left, remove '%s'\n", slink);
if (!test) {
unlink(slink);
util_delete_path(udev, slink);
}
goto out;
}
/* find the device with the highest priority */
target[0] = '\0';
udev_list_entry_foreach(dev_entry, udev_list_get_entry(&dev_list)) {
const char *syspath;
struct udev_device *dev_db;
const char *devnode;
syspath = udev_list_entry_get_name(dev_entry);
dbg(udev, "found '%s' for '%s'\n", syspath, slink);
/* did we find ourself? we win, if we have the same priority */
if (strcmp(udev_device_get_syspath(dev), syspath) == 0) {
dbg(udev, "compare (our own) priority of '%s' %i >= %i\n",
udev_device_get_devpath(dev), udev_device_get_devlink_priority(dev), priority);
if (strcmp(udev_device_get_devnode(dev), slink) == 0) {
info(udev, "'%s' is our device node, database inconsistent, skip link update\n",
udev_device_get_devnode(dev));
} else if (target[0] == '\0' || udev_device_get_devlink_priority(dev) >= priority) {
priority = udev_device_get_devlink_priority(dev);
util_strlcpy(target, udev_device_get_devnode(dev), sizeof(target));
}
continue;
}
/* another device, read priority from database */
dev_db = udev_device_new_from_syspath(udev, syspath);
if (dev_db == NULL)
continue;
devnode = udev_device_get_devnode(dev_db);
if (devnode != NULL) {
if (strcmp(devnode, slink) == 0) {
info(udev, "'%s' is a device node of '%s', skip link update\n",
devnode, syspath);
} else {
dbg(udev, "compare priority of '%s' %i > %i\n",
udev_device_get_devpath(dev_db),
udev_device_get_devlink_priority(dev_db),
priority);
if (target[0] == '\0' || udev_device_get_devlink_priority(dev_db) > priority) {
priority = udev_device_get_devlink_priority(dev_db);
util_strlcpy(target, devnode, sizeof(target));
}
}
}
udev_device_unref(dev_db);
}
udev_list_cleanup_entries(udev, &dev_list);
if (target[0] == '\0') {
info(udev, "no current target for '%s' found\n", slink);
rc = 1;
goto out;
}
/* create symlink to the target with the highest priority */
info(udev, "'%s' with target '%s' has the highest priority %i, create it\n", slink, target, priority);
if (!test) {
util_create_path(udev, slink);
node_symlink(udev, target, slink);
}
out:
return rc;
}