libsysfs: translate devpath of the symlinked class devices to its real path

diff --git a/libsysfs/sysfs_class.c b/libsysfs/sysfs_class.c
index edf751b124c515f01c96f37409ba722714e6ba48..102f09f17af260fe92f66a9d412627e432c50496 100644 (file)
--- a/libsysfs/sysfs_class.c
+++ b/libsysfs/sysfs_class.c
@@ -128,28 +128,45 @@ static void set_classdev_classname(struct sysfs_class_device *cdev)
 struct sysfs_class_device *sysfs_open_class_device_path(const char *path)
 {
        struct sysfs_class_device *cdev;
+       char temp_path[SYSFS_PATH_MAX];
 
        if (!path) {
                errno = EINVAL;
                return NULL;
        }
+
+       /*
+        * Post linux-2.6.14 driver model supports nested classes with
+        * links to the nested hierarchy at /sys/class/xxx/. Check for
+        * a link to the actual class device if a directory isn't found
+        */
        if (sysfs_path_is_dir(path)) {
-               dprintf("%s is not a valid path to a class device\n", path);
-               return NULL;
-       }
+               dprintf("%s: Directory not found, checking for a link\n", path);
+               if (!sysfs_path_is_link(path)) {
+                       if (sysfs_get_link(path, temp_path, SYSFS_PATH_MAX)) {
+                               dprintf("Error retrieving link at %s\n", path);
+                               return NULL;
+                       }
+               } else {
+                       dprintf("%s is not a valid class device path\n", path);
+                       return NULL;
+               }
+       } else
+               safestrcpy(temp_path, path);
+
        cdev = alloc_class_device();
        if (!cdev) {
                dprintf("calloc failed\n");
                return NULL;
        }
-       if (sysfs_get_name_from_path(path, cdev->name, SYSFS_NAME_LEN)) {
+       if (sysfs_get_name_from_path(temp_path, cdev->name, SYSFS_NAME_LEN)) {
                errno = EINVAL;
                dprintf("Error getting class device name\n");
                sysfs_close_class_device(cdev);
                return NULL;
        }
 
-       safestrcpy(cdev->path, path);
+       safestrcpy(cdev->path, temp_path);
        if (sysfs_remove_trailing_slash(cdev->path)) {
                dprintf("Invalid path to class device %s\n", cdev->path);
                sysfs_close_class_device(cdev);
@@ -455,12 +472,10 @@ struct sysfs_class_device *sysfs_get_class_device(struct sysfs_class *cls,
        safestrcpy(path, cls->path);
        safestrcat(path, "/");
        safestrcat(path, name);
-       if (!sysfs_path_is_dir(path)) {
-               cdev = sysfs_open_class_device_path(path);
-               if (!cdev) {
-                       dprintf("Error opening class device at %s\n", path);
-                       return NULL;
-               }
+       cdev = sysfs_open_class_device_path(path);
+       if (!cdev) {
+               dprintf("Error opening class device at %s\n", path);
+               return NULL;
        }
        if (!cls->devices)
                cls->devices = dlist_new_with_delete
@@ -471,6 +486,40 @@ struct sysfs_class_device *sysfs_get_class_device(struct sysfs_class *cls,
        return cdev;
 }
 
+/**
+ * Add class devices to list
+ */
+static void add_cdevs_to_classlist(struct sysfs_class *cls, struct dlist *list)
+{
+       char path[SYSFS_PATH_MAX], *cdev_name;
+       struct sysfs_class_device *cdev = NULL;
+
+       if (cls == NULL || list == NULL)
+               return;
+
+       dlist_for_each_data(list, cdev_name, char) {
+               if (cls->devices) {
+                       cdev = (struct sysfs_class_device *)
+                               dlist_find_custom(cls->devices,
+                               (void *)cdev_name, cdev_name_equal);
+                       if (cdev)
+                               continue;
+               }
+               safestrcpy(path, cls->path);
+               safestrcat(path, "/");
+               safestrcat(path, cdev_name);
+               cdev = sysfs_open_class_device_path(path);
+               if (cdev) {
+                       if (!cls->devices)
+                               cls->devices = dlist_new_with_delete
+                               (sizeof(struct sysfs_class_device),
+                                sysfs_close_cls_dev);
+                       dlist_unshift_sorted(cls->devices, cdev,
+                                       sort_list);
+               }
+       }
+}
+
 /**
  * sysfs_get_class_devices: get all class devices in the given class
  * @cls: sysfs_class whose devices list is needed
@@ -480,42 +529,29 @@ struct sysfs_class_device *sysfs_get_class_device(struct sysfs_class *cls,
 struct dlist *sysfs_get_class_devices(struct sysfs_class *cls)
 {
        char path[SYSFS_PATH_MAX];
-       char *cdev_name;
-       struct sysfs_class_device *cdev = NULL;
-       struct dlist *dirlist;
+       struct dlist *dirlist, *linklist;
 
        if (!cls) {
                errno = EINVAL;
                return NULL;
        }
 
+       /*
+        * Post linux-2.6.14, we have nested classes and links under
+        * /sys/class/xxx/. are also valid class devices
+        */
        safestrcpy(path, cls->path);
        dirlist = read_dir_subdirs(path);
        if (dirlist) {
-               dlist_for_each_data(dirlist, cdev_name, char) {
-                       if (cls->devices) {
-                               cdev = (struct sysfs_class_device *)
-                                       dlist_find_custom(cls->devices, 
-                                       (void *)cdev_name, cdev_name_equal);
-                               if (cdev)
-                                       continue;
-                       }
-                       safestrcpy(path, cls->path);
-                       safestrcat(path, "/");
-                       safestrcat(path, cdev_name);
-                       cdev = sysfs_open_class_device_path(path);
-                       if (cdev) {
-                               if (!cls->devices)
-                                       cls->devices = dlist_new_with_delete
-                                       (sizeof(struct sysfs_class_device),
-                                        sysfs_close_cls_dev);
-                               dlist_unshift_sorted(cls->devices, cdev,
-                                               sort_list);
-                       }
-               }
+               add_cdevs_to_classlist(cls, dirlist);
                sysfs_close_list(dirlist);
        }
-       
+
+       linklist = read_dir_links(path);
+       if (linklist) {
+               add_cdevs_to_classlist(cls, linklist);
+               sysfs_close_list(linklist);
+       }
+
        return cls->devices;
 }
-