chiark / gitweb /
[PATCH] libsysfs: work around a klibc bug
[elogind.git] / libsysfs / sysfs_class.c
index a0273565d5610f80524a76736023eb5cb053b66b..4ea7f41c99c293410482acfed888498e47f79d27 100644 (file)
@@ -38,8 +38,7 @@ static int class_name_equal(void *a, void *b)
        if (a == NULL || b == NULL)
                return 0;
 
-       if (strcmp(((unsigned char *)a), ((struct sysfs_class_device *)b)->name)
-               == 0)
+       if (strcmp(((char *)a), ((struct sysfs_class_device *)b)->name) == 0)
                return 1;
 
        return 0;
@@ -58,13 +57,15 @@ void sysfs_close_class_device(struct sysfs_class_device *dev)
                        sysfs_close_device(dev->sysdevice);
                if (dev->driver != NULL)
                        sysfs_close_driver(dev->driver);
+               if (dev->parent != NULL)
+                       sysfs_close_class_device(dev->parent);
                free(dev);
        }
 }
 
 /**
  * sysfs_close_class: close single class
- * @class: class structure
+ * @cls: class structure
  */
 void sysfs_close_class(struct sysfs_class *cls)
 {
@@ -96,52 +97,6 @@ static struct sysfs_class *alloc_class(void)
        return (struct sysfs_class *)calloc(1, sizeof(struct sysfs_class));
 }
 
-/**
- * open_class_dir: opens up sysfs class directory
- * returns sysfs_directory struct with success and NULL with error
- */
-static struct sysfs_directory *open_class_dir(const unsigned char *name)
-{
-       struct sysfs_directory *classdir = NULL;
-       unsigned char classpath[SYSFS_PATH_MAX];
-
-       if (name == NULL) {
-               errno = EINVAL;
-               return NULL;
-       }
-
-       memset(classpath, 0, SYSFS_PATH_MAX);
-       if ((sysfs_get_mnt_path(classpath, SYSFS_PATH_MAX)) != 0) {
-               dprintf("Sysfs not supported on this system\n");
-               return NULL;
-       }
-
-       /* 
-        * We shall now treat "block" also as a class. Hence, check here
-        * if "name" is "block" and proceed accordingly
-        */
-       if (strcmp(name, SYSFS_BLOCK_NAME) == 0) {
-               strcat(classpath, SYSFS_BLOCK_DIR);
-       } else {
-               strcat(classpath, SYSFS_CLASS_DIR);
-               strcat(classpath, "/");
-               strcat(classpath, name);
-       }
-       classdir = sysfs_open_directory(classpath);
-       if (classdir == NULL) {
-               errno = EINVAL;
-               dprintf("Class %s not supported on this system\n", name);
-               return NULL;
-       }
-       if ((sysfs_read_directory(classdir)) != 0) {
-               dprintf("Error reading %s class dir %s\n", name, classpath);
-               sysfs_close_directory(classdir);
-               return NULL;
-       }
-
-       return classdir;
-}
-
 /** 
  * set_classdev_classname: Grabs classname from path
  * @cdev: class device to set
@@ -149,23 +104,21 @@ static struct sysfs_directory *open_class_dir(const unsigned char *name)
  */
 static void set_classdev_classname(struct sysfs_class_device *cdev)
 {
-       unsigned char *c = NULL, *e = NULL;
+       char *c = NULL, *e = NULL;
        int count = 0;
 
-       c = strstr(cdev->path, SYSFS_CLASS_DIR);
-       if (c == NULL) 
-               c = strstr(cdev->path, SYSFS_BLOCK_DIR);
-       else {
-               c++;
-               while (c != NULL && *c != '/') 
-                       c++;
+       c = strstr(cdev->path, SYSFS_CLASS_NAME);
+       if (c == NULL) {
+               c = strstr(cdev->path, SYSFS_BLOCK_NAME);
+       } else {
+               c = strchr(c, '/');
        }
 
-       if (c == NULL) 
-               strcpy(cdev->classname, SYSFS_UNKNOWN);
-
+       if (c == NULL)
+               safestrcpy(cdev->classname, SYSFS_UNKNOWN);
        else {
-               c++;
+               if (*c == '/')
+                       c++;
                e = c;
                while (e != NULL && *e != '/' && *e != '\0') {
                        e++;
@@ -176,22 +129,22 @@ static void set_classdev_classname(struct sysfs_class_device *cdev)
 }
 
 /**
- * sysfs_open_class_device: Opens and populates class device
+ * sysfs_open_class_device_path: Opens and populates class device
  * @path: path to class device.
  * returns struct sysfs_class_device with success and NULL with error.
  */
-struct sysfs_class_device *sysfs_open_class_device(const unsigned char *path)
+struct sysfs_class_device *sysfs_open_class_device_path(const char *path)
 {
        struct sysfs_class_device *cdev = NULL;
-       struct sysfs_directory *dir = NULL;
-       struct sysfs_link *curl = NULL;
-       struct sysfs_device *sdev = NULL;
-       struct sysfs_driver *drv = NULL;
 
        if (path == NULL) {
                errno = EINVAL;
                return NULL;
        }
+       if ((sysfs_path_is_dir(path)) != 0) {
+               dprintf("%s is not a valid path to a class device\n", path);
+               return NULL;
+       }
        cdev = alloc_class_device();
        if (cdev == NULL) {
                dprintf("calloc failed\n");
@@ -199,132 +152,119 @@ struct sysfs_class_device *sysfs_open_class_device(const unsigned char *path)
        }
        if ((sysfs_get_name_from_path(path, cdev->name, SYSFS_NAME_LEN)) != 0) {
                errno = EINVAL;
-               dprintf("Invalid class device path %s\n", path);
+               dprintf("Error getting class device name\n");
                sysfs_close_class_device(cdev);
                return NULL;
        }
 
-       dir = sysfs_open_directory(path);
-       if (dir == NULL) {
-               dprintf("Error opening class device at %s\n", path);
+       safestrcpy(cdev->path, path);
+       if ((sysfs_remove_trailing_slash(cdev->path)) != 0) {
+               dprintf("Invalid path to class device %s\n", cdev->path);
                sysfs_close_class_device(cdev);
                return NULL;
        }
-       if ((sysfs_read_directory(dir)) != 0) {
-               dprintf("Error reading class device at %s\n", path);
-               sysfs_close_directory(dir);
-               sysfs_close_class_device(cdev);
-               return NULL;
-       }
-       sysfs_read_all_subdirs(dir);
-       cdev->directory = dir;
-       strcpy(cdev->path, dir->path);
        set_classdev_classname(cdev);
 
-       /* get driver and device, if implemented */
-       if (cdev->directory->links != NULL) {
-               dlist_for_each_data(cdev->directory->links, curl,
-                               struct sysfs_link) {
-                       if (strncmp(curl->name, SYSFS_DEVICES_NAME, 6) == 0) {
-                               sdev = sysfs_open_device(curl->target);
-                               if (sdev != NULL) {
-                                       cdev->sysdevice = sdev;
-                                       if (cdev->driver != NULL) 
-                                               strncpy(sdev->driver_name,
-                                                       cdev->driver->name, 
-                                                       SYSFS_NAME_LEN);
-                               }
-                       } else if (strncmp(curl->name, 
-                                               SYSFS_DRIVERS_NAME, 6) == 0) {
-                               drv = sysfs_open_driver(curl->target);
-                               if (drv != NULL) {
-                                       cdev->driver = drv;
-                                       if (cdev->sysdevice != NULL) {
-                                               strncpy(cdev->sysdevice->name,
-                                                               drv->name, 
-                                                               SYSFS_NAME_LEN);
-                                               if (drv->devices == NULL)
-                                                       drv->devices = 
-                                                               dlist_new
-                                                               (sizeof(struct 
-                                                               sysfs_device));
-                                               dlist_unshift(drv->devices, 
-                                                       cdev->sysdevice);
-                                       }
-                               }
-                       }
-               }
-       }
        return cdev;
 }
 
 /**
- * get_all_class_devices: gets all devices for class
- * @class: class to get devices for
- * returns 0 with success and -1 with failure
+ * sysfs_get_class_devices: gets all devices for class
+ * @cls: class to get devices for
+ * returns dlist of class_devices with success and NULL with error
  */
-static int get_all_class_devices(struct sysfs_class *cls)
+struct dlist *sysfs_get_class_devices(struct sysfs_class *cls)
 {
        struct sysfs_class_device *dev = NULL;
        struct sysfs_directory *cur = NULL;
 
-       if (cls == NULL || cls->directory == NULL) {
+       if (cls == NULL) {
                errno = EINVAL;
-               return -1;
+               return NULL;
        }
-       if (cls->directory->subdirs == NULL)
-               return 0;
-       dlist_for_each_data(cls->directory->subdirs, cur, 
-                       struct sysfs_directory) {
-               dev = sysfs_open_class_device(cur->path);
-               if (dev == NULL) {
-                       dprintf("Error opening device at %s\n", cur->path);
-                       continue;
-               }
-               if (cls->devices == NULL)
-                       cls->devices = dlist_new_with_delete
+
+       if (cls->devices != NULL) 
+               return cls->devices;
+
+       if (cls->directory == NULL) {
+               cls->directory = sysfs_open_directory(cls->path);
+               if (cls->directory == NULL) 
+                       return NULL;
+       }
+
+       if ((sysfs_read_dir_subdirs(cls->directory)) != 0) 
+               return NULL;
+
+       if (cls->directory->subdirs != NULL) {
+               dlist_for_each_data(cls->directory->subdirs, cur, 
+                                               struct sysfs_directory) {
+                       dev = sysfs_open_class_device_path(cur->path);
+                       if (dev == NULL) {
+                               dprintf("Error opening device at %s\n", 
+                                                               cur->path);
+                               continue;
+                       }
+                       if (cls->devices == NULL)
+                               cls->devices = dlist_new_with_delete
                                        (sizeof(struct sysfs_class_device),
                                                        sysfs_close_cls_dev);
-               dlist_unshift(cls->devices, dev);
+                       dlist_unshift_sorted(cls->devices, dev, sort_list);
+               }
        }
-       return 0;
+       return cls->devices;
 }
 
 /**
  * sysfs_open_class: opens specific class and all its devices on system
  * returns sysfs_class structure with success or NULL with error.
  */
-struct sysfs_class *sysfs_open_class(const unsigned char *name)
+struct sysfs_class *sysfs_open_class(const char *name)
 {
        struct sysfs_class *cls = NULL;
-       struct sysfs_directory *classdir = NULL;
+       char classpath[SYSFS_PATH_MAX];
 
        if (name == NULL) {
                errno = EINVAL;
                return NULL;
        }
 
+       memset(classpath, 0, SYSFS_PATH_MAX);
+        if ((sysfs_get_mnt_path(classpath, SYSFS_PATH_MAX)) != 0) {
+                dprintf("Sysfs not supported on this system\n");
+                return NULL;
+        }
+
+       /* 
+        * We shall now treat "block" also as a class. Hence, check here
+        * if "name" is "block" and proceed accordingly
+        */
+       if (strcmp(name, SYSFS_BLOCK_NAME) == 0) {
+               safestrcat(classpath, "/");
+               safestrcat(classpath, SYSFS_BLOCK_NAME);
+       } else {
+               safestrcat(classpath, "/");
+               safestrcat(classpath, SYSFS_CLASS_NAME);
+               safestrcat(classpath, "/");
+               safestrcat(classpath, name);
+       }
+       if ((sysfs_path_is_dir(classpath)) != 0) {
+               dprintf("Class %s not found on the system\n", name);
+               return NULL;
+       }
+
        cls = alloc_class();
        if (cls == NULL) {
                dprintf("calloc failed\n");
                return NULL;
        }
-       strcpy(cls->name, name);        
-       classdir = open_class_dir(name);
-       if (classdir == NULL) {
-               dprintf("Invalid class, %s not supported on this system\n",
-                       name);
-               sysfs_close_class(cls);
-               return NULL;
-       }
-       cls->directory = classdir;
-       strcpy(cls->path, classdir->path);
-       if ((get_all_class_devices(cls)) != 0) {
-               dprintf("Error reading %s class devices\n", name);
+       safestrcpy(cls->name, name);    
+       safestrcpy(cls->path, classpath);
+       if ((sysfs_remove_trailing_slash(cls->path)) != 0) {
+               dprintf("Invalid path to class device %s\n", cls->path);
                sysfs_close_class(cls);
                return NULL;
        }
-
+       
        return cls;
 }
 
@@ -333,18 +273,220 @@ struct sysfs_class *sysfs_open_class(const unsigned char *name)
  * @class: class to find device on
  * @name: class name of the device
  */ 
-struct sysfs_class_device *sysfs_get_class_device(struct sysfs_class *class,
-                                       unsigned char *name)
+struct sysfs_class_device *sysfs_get_class_device(struct sysfs_class *cls,
+                                       char *name)
 {
-       if (class == NULL || name == NULL) {
+       if (cls == NULL || name == NULL) {
                errno = EINVAL;
                return NULL;
        }
 
-       return (struct sysfs_class_device *)dlist_find_custom(class->devices,
+       if (cls->devices == NULL) {
+               cls->devices = sysfs_get_class_devices(cls);
+               if (cls->devices == NULL) 
+                       return NULL;
+       }
+       return (struct sysfs_class_device *)dlist_find_custom(cls->devices,
                        name, class_name_equal);
 }
 
+/**
+ * sysfs_get_classdev_device: returns the sysfs_device corresponding to
+ *             sysfs_class_device, if present
+ * @clsdev: class device whose sysfs_device is required
+ * Returns sysfs_device on success, NULL on error or if device is not
+ * implemented
+ */ 
+struct sysfs_device *sysfs_get_classdev_device
+                       (struct sysfs_class_device *clsdev)
+{
+       struct sysfs_link *devlink = NULL;
+       char devpath[SYSFS_PATH_MAX];
+       
+       if (clsdev == NULL) {
+               errno = EINVAL;
+               return NULL;
+       }
+       safestrcpy(devpath, clsdev->path);
+       safestrcat(devpath, "/device");
+       if ((sysfs_path_is_link(devpath)) != 0) {
+               if (clsdev->sysdevice != NULL) {
+                       sysfs_close_device(clsdev->sysdevice);
+                       clsdev->sysdevice = NULL;
+               }
+               return NULL;
+       }
+       
+       if (clsdev->directory == NULL) {
+               clsdev->directory = sysfs_open_directory(clsdev->path);
+               if (clsdev->directory == NULL)
+                       return NULL;
+       }
+       devlink = sysfs_get_directory_link(clsdev->directory, "device");
+       if (devlink == NULL) {
+               if (clsdev->sysdevice != NULL) {
+                       dprintf("Device link no longer exists\n");
+                       sysfs_close_device(clsdev->sysdevice);
+                       clsdev->sysdevice = NULL;
+               }
+               return NULL;
+       }
+
+       if (clsdev->sysdevice != NULL) {
+               if (!strncmp(devlink->target, clsdev->sysdevice->path,
+                                               SYSFS_PATH_MAX)) 
+                       /* sysdevice hasn't changed */
+                       return (clsdev->sysdevice);
+               else 
+                       /* come here only if the device link for has changed */
+                       sysfs_close_device(clsdev->sysdevice);
+       }
+
+       clsdev->sysdevice = sysfs_open_device_path(devlink->target);
+       if (clsdev->sysdevice == NULL)
+               return NULL;
+
+       return (clsdev->sysdevice);
+}
+                               
+/**
+ * sysfs_get_classdev_driver: returns the sysfs_driver corresponding to
+ *             sysfs_class_device, if present
+ * @clsdev: class device whose sysfs_device is required
+ * Returns sysfs_driver on success, NULL on error or if driver is not
+ * implemented
+ */ 
+struct sysfs_driver *sysfs_get_classdev_driver
+                       (struct sysfs_class_device *clsdev)
+{
+       struct sysfs_link *drvlink = NULL;
+       char drvpath[SYSFS_PATH_MAX];
+       
+       if (clsdev == NULL) {
+               errno = EINVAL;
+               return NULL;
+       }
+       safestrcpy(drvpath, clsdev->path);
+       safestrcat(drvpath, "/driver");
+       if ((sysfs_path_is_link(drvpath)) != 0) {
+               if (clsdev->driver != NULL) {
+                       sysfs_close_driver(clsdev->driver);
+                       clsdev->driver = NULL;
+               }
+               return NULL;
+       }
+        
+       if (clsdev->directory == NULL) {
+               clsdev->directory = sysfs_open_directory(clsdev->path);
+               if (clsdev->directory == NULL)
+                       return NULL;
+       }
+       drvlink = sysfs_get_directory_link(clsdev->directory, "driver");
+       if (drvlink == NULL) {
+               if (clsdev->driver != NULL) {
+                       dprintf("Driver link no longer exists\n");
+                       sysfs_close_driver(clsdev->driver);
+                       clsdev->driver = NULL;
+               }
+               return NULL;
+       }
+       if (clsdev->driver != NULL) {
+               if (!strncmp(drvlink->target, clsdev->driver->path,
+                                                       SYSFS_PATH_MAX))
+                       /* driver hasn't changed */
+                       return (clsdev->driver);
+               else
+                       /* come here only if the device link for has changed */
+                       sysfs_close_driver(clsdev->driver);
+       }
+               
+       clsdev->driver = sysfs_open_driver_path(drvlink->target);
+       if (clsdev->driver == NULL)
+               return NULL;
+
+       return (clsdev->driver);
+}
+
+/** 
+ * get_blockdev_parent: Get the parent class device for a "block" subsystem 
+ *             device if present
+ * @clsdev: block subsystem class device whose parent needs to be found
+ * Returns 0 on success and 1 on error
+ */
+static int get_blockdev_parent(struct sysfs_class_device *clsdev)
+{
+       char parent_path[SYSFS_PATH_MAX], *c = NULL;
+
+       safestrcpy(parent_path, clsdev->path);
+       c = strstr(parent_path, SYSFS_BLOCK_NAME);
+       if (c == NULL) {
+               dprintf("Class device %s does not belong to BLOCK subsystem\n",
+                               clsdev->name);
+               return 1;
+       }
+       c += strlen(SYSFS_BLOCK_NAME);
+       if (*c == '/')
+               c++;
+       else
+               goto errout;
+
+       /* validate whether the given class device is a partition or not */
+        if ((strncmp(c, clsdev->name, strlen(clsdev->name))) == 0) {
+                dprintf("%s not a partition\n", clsdev->name);
+                return 1;
+        }
+                     
+       c = strchr(c, '/');
+       if (c == NULL)
+               goto errout;
+
+       *c = '\0';
+                                       
+       clsdev->parent = sysfs_open_class_device_path(parent_path);
+       if (clsdev->parent == NULL) {
+               dprintf("Error opening the parent class device at %s\n", 
+                                                               parent_path);
+               return 1;
+       }
+       return 0;
+
+errout:
+       dprintf("Invalid path %s\n", clsdev->path);
+       return 1;
+}
+
+/**
+ * sysfs_get_classdev_parent: Retrieves the parent of a class device. 
+ *     eg., when working with hda1, this function can be used to retrieve the
+ *             sysfs_class_device for hda
+ *             
+ * @clsdev: class device whose parent details are required.
+ * Returns sysfs_class_device of the parent on success, NULL on failure
+ */ 
+struct sysfs_class_device *sysfs_get_classdev_parent
+                               (struct sysfs_class_device *clsdev)
+{
+       if (clsdev == NULL) {
+               errno = EINVAL;
+               return NULL;
+       }
+       if (clsdev->parent != NULL)
+               return (clsdev->parent);
+       
+       /* 
+        * As of now, only block devices have a parent child heirarchy in sysfs
+        * We do not know, if, in the future, more classes will have a similar
+        * structure. Hence, we now call a specialized function for block and
+        * later we can add support functions for other subsystems as required.
+        */ 
+       if (!(strncmp(clsdev->classname, SYSFS_BLOCK_NAME, 
+                                       sizeof(SYSFS_BLOCK_NAME)))) {
+               if ((get_blockdev_parent(clsdev)) == 0) 
+                       return (clsdev->parent);
+       }
+       return NULL;
+}
+
 /**
  * get_classdev_path: given the class and a device in the class, return the
  *             absolute path to the device
@@ -354,8 +496,8 @@ struct sysfs_class_device *sysfs_get_class_device(struct sysfs_class *class,
  * @psize: size of "path"
  * Returns 0 on SUCCESS or -1 on error
  */
-static int get_classdev_path(const unsigned char *classname
-               const unsigned char *clsdev, unsigned char *path, size_t len)
+static int get_classdev_path(const char *classname, const char *clsdev
+               char *path, size_t len)
 {
        if (classname == NULL || clsdev == NULL || path == NULL) {
                errno = EINVAL;
@@ -365,20 +507,23 @@ static int get_classdev_path(const unsigned char *classname,
                 dprintf("Error getting sysfs mount path\n");
                 return -1;
        }
-       if (strcmp(classname, SYSFS_BLOCK_NAME) == 0) {
-               strcat(path, SYSFS_BLOCK_DIR);
+       if (strncmp(classname, SYSFS_BLOCK_NAME,
+                               sizeof(SYSFS_BLOCK_NAME)) == 0) {
+               safestrcatmax(path, "/", len);
+               safestrcatmax(path, SYSFS_BLOCK_NAME, len);
        } else {
-               strcat(path, SYSFS_CLASS_DIR);
-               strcat(path, "/");
-               strcat(path, classname);
+               safestrcatmax(path, "/", len);
+               safestrcatmax(path, SYSFS_CLASS_NAME, len);
+               safestrcatmax(path, "/", len);
+               safestrcatmax(path, classname, len);
        }
-       strcat(path, "/");
-       strcat(path, clsdev);
+       safestrcatmax(path, "/", len);
+       safestrcatmax(path, clsdev, len);
        return 0;
 }
 
 /**
- * sysfs_open_class_device_by_name: Locates a specific class_device and returns it.
+ * sysfs_open_class_device: Locates a specific class_device and returns it.
  * Class_device must be closed using sysfs_close_class_device
  * @classname: Class to search
  * @name: name of the class_device
@@ -386,10 +531,10 @@ static int get_classdev_path(const unsigned char *classname,
  * NOTE:
  *     Call sysfs_close_class_device() to close the class device
  */
-struct sysfs_class_device *sysfs_open_class_device_by_name
-               (const unsigned char *classname, const unsigned char *name)
+struct sysfs_class_device *sysfs_open_class_device
+               (const char *classname, const char *name)
 {
-       unsigned char devpath[SYSFS_PATH_MAX];
+       char devpath[SYSFS_PATH_MAX];
        struct sysfs_class_device *cdev = NULL;
 
        if (classname == NULL || name == NULL) {
@@ -405,7 +550,7 @@ struct sysfs_class_device *sysfs_open_class_device_by_name
                return NULL;
        }
        
-       cdev = sysfs_open_class_device(devpath);
+       cdev = sysfs_open_class_device_path(devpath);
        if (cdev == NULL) {
                dprintf("Error getting class device %s from class %s\n",
                                name, classname);
@@ -422,12 +567,49 @@ struct sysfs_class_device *sysfs_open_class_device_by_name
  */
 struct dlist *sysfs_get_classdev_attributes(struct sysfs_class_device *cdev)
 {
-       if (cdev == NULL || cdev->directory == NULL)
+       if (cdev == NULL)
                return NULL;
 
+       if (cdev->directory == NULL) {
+               cdev->directory = sysfs_open_directory(cdev->path);
+               if (cdev->directory == NULL) 
+                       return NULL;
+       }
+       if (cdev->directory->attributes == NULL) {
+               if ((sysfs_read_dir_attributes(cdev->directory)) != 0) 
+                       return NULL;
+       }
        return (cdev->directory->attributes);
 }
 
+/**
+ * sysfs_refresh_clsassdev_attributes: refreshes the driver's list of attributes
+ * @clsdev: sysfs_class_device whose attributes to refresh
+ *
+ * NOTE: Upon return, prior references to sysfs_attributes for this classdev
+ *              _may_ not be valid
+ *
+ * Returns list of attributes on success and NULL on failure
+ */
+struct dlist *sysfs_refresh_classdev_attributes
+                       (struct sysfs_class_device *clsdev)
+{
+       if (clsdev == NULL) {
+               errno = EINVAL;
+               return NULL;
+       }
+
+       if (clsdev->directory == NULL)
+               return (sysfs_get_classdev_attributes(clsdev));
+
+       if ((sysfs_refresh_dir_attributes(clsdev->directory)) != 0) {
+               dprintf("Error refreshing class_device attributes\n");
+               return NULL;
+       }
+
+       return (clsdev->directory->attributes);
+}
+
 /**
  * sysfs_get_classdev_attr: searches class device's attributes by name
  * @clsdev: class device to look through
@@ -435,22 +617,49 @@ struct dlist *sysfs_get_classdev_attributes(struct sysfs_class_device *cdev)
  * returns sysfs_attribute reference with success or NULL with error
  */
 struct sysfs_attribute *sysfs_get_classdev_attr
-               (struct sysfs_class_device *clsdev, const unsigned char *name)
+               (struct sysfs_class_device *clsdev, const char *name)
 {
        struct sysfs_attribute *cur = NULL;
-
-       if (clsdev == NULL || clsdev->directory == NULL ||
-               clsdev->directory->attributes == NULL || name == NULL) {
+       struct sysfs_directory *sdir = NULL;
+       struct dlist *attrlist = NULL;
+       
+       if (clsdev == NULL || name == NULL) {
                errno = EINVAL;
                return NULL;
        }
+       
+       /* 
+        * First, see if it's in the current directory. Then look at 
+        * subdirs since class devices can have subdirs of attributes.
+        */ 
+       attrlist = sysfs_get_classdev_attributes(clsdev);
+       if (attrlist != NULL) {
+               cur = sysfs_get_directory_attribute(clsdev->directory,
+                                               (char *)name);
+               if (cur != NULL)
+                       return cur;
+       }
+
+       if (clsdev->directory == NULL)
+               return NULL;
 
-       cur = sysfs_get_directory_attribute(clsdev->directory,
-                                               (unsigned char *)name);
-       if (cur != NULL)
-               return cur;
-
-       return NULL;
+       if (clsdev->directory->subdirs == NULL) 
+               if ((sysfs_read_dir_subdirs(clsdev->directory)) != 0 ||
+                   clsdev->directory->subdirs == NULL) 
+                       return NULL;
+
+       if (clsdev->directory->subdirs != NULL) {
+               dlist_for_each_data(clsdev->directory->subdirs, sdir,
+                                               struct sysfs_directory) {
+                       if ((sysfs_path_is_dir(sdir->path)) != 0) 
+                               continue;
+                       cur = sysfs_get_directory_attribute(sdir,
+                                                       (char *)name);
+                       if (cur == NULL)
+                               continue;
+               }
+       }
+       return cur;
 }
 
 /**
@@ -464,11 +673,11 @@ struct sysfs_attribute *sysfs_get_classdev_attr
  *     A call to sysfs_close_attribute() is required to close the
  *     attribute returned and to free memory
  */
-struct sysfs_attribute *sysfs_open_classdev_attr(const unsigned char *classname,
-               const unsigned char *dev, const unsigned char *attrib)
+struct sysfs_attribute *sysfs_open_classdev_attr(const char *classname,
+               const char *dev, const char *attrib)
 {
        struct sysfs_attribute *attribute = NULL;
-       unsigned char path[SYSFS_PATH_MAX];
+       char path[SYSFS_PATH_MAX];
 
        if (classname == NULL || dev == NULL || attrib == NULL) {
                errno = EINVAL;
@@ -480,8 +689,8 @@ struct sysfs_attribute *sysfs_open_classdev_attr(const unsigned char *classname,
                                                dev, classname);
                return NULL;
        }
-       strcat(path, "/");
-       strcat(path, attrib);
+       safestrcat(path, "/");
+       safestrcat(path, attrib);
        attribute = sysfs_open_attribute(path);
        if (attribute == NULL) {
                dprintf("Error opening attribute %s on class device %s\n",
@@ -496,3 +705,4 @@ struct sysfs_attribute *sysfs_open_classdev_attr(const unsigned char *classname,
        }
        return attribute;
 }
+