X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=blobdiff_plain;f=libsysfs%2Fsysfs_device.c;h=7087730d5f16d7a830c658d3ef22be8b44dd9c77;hp=83c3adc080cd3b81ffc29a13c03392660659fd51;hb=f385ff6512012a75b8381938dd3f55f991b53e9a;hpb=8d1b4df2192915dc94442c1ef3327a28a57b3615

diff --git a/libsysfs/sysfs_device.c b/libsysfs/sysfs_device.c
index 83c3adc08..7087730d5 100644
--- a/libsysfs/sysfs_device.c
+++ b/libsysfs/sysfs_device.c
@@ -3,7 +3,7 @@
  *
  * Generic device utility functions for libsysfs
  *
- * Copyright (C) IBM Corp. 2003
+ * Copyright (C) IBM Corp. 2003-2005
  *
  *  This library is free software; you can redistribute it and/or
  *  modify it under the terms of the GNU Lesser General Public
@@ -24,48 +24,64 @@
 #include "sysfs.h"
 
 /**
- * get_dev_driver: fills in the dev->driver_name field, but searches by
- *	opening subsystem. Only to be used if no driver link exists in
- *	device directory.
- *
- * Returns 0 on SUCCESS and 1 on error
+ * get_dev_driver: fills in the dev->driver_name field 
+ * Returns 0 on SUCCESS and -1 on error
  */
 static int get_dev_driver(struct sysfs_device *dev)
 {
-	struct dlist *drvlist = NULL;
-	char path[SYSFS_PATH_MAX], devpath[SYSFS_PATH_MAX];
-	char *drv = NULL, *c = NULL;
-	
-	if (dev == NULL) {
+	struct dlist *drvlist;
+	char path[SYSFS_PATH_MAX];
+	char devpath[SYSFS_PATH_MAX];
+	char *drv = NULL, *c;
+
+	if (!dev) {
 		errno = EINVAL;
-		return 1;
+		return -1;
+	}
+
+	memset(path, 0, SYSFS_PATH_MAX);
+	memset(devpath, 0, SYSFS_PATH_MAX);
+	safestrcpymax(path, dev->path, SYSFS_PATH_MAX);
+	safestrcatmax(path, "/driver", SYSFS_PATH_MAX);
+	if (!sysfs_path_is_link(path)) {
+		if (!sysfs_get_link(path, devpath, SYSFS_PATH_MAX)) {
+			if (sysfs_get_name_from_path(devpath, 
+					dev->driver_name, SYSFS_NAME_LEN))
+				return -1;
+		}
+		return 0;
 	}
+
+	/*
+	 * Devices on on earlier kernels do not have the "driver" link.
+	 * Look it up in the bus directory.
+	 */
 	if (dev->bus[0] == '\0')
-		return 1;
+		return -1;
 	memset(path, 0, SYSFS_PATH_MAX);
 	memset(devpath, 0, SYSFS_PATH_MAX);
-	safestrcpy(path, SYSFS_BUS_NAME);
+	safestrcpy(path, dev->path);
+	c = strstr(path, SYSFS_DEVICES_NAME);
+	if (c == NULL) {
+		dprintf("Invalid path to device - %s\n", dev->path);
+		return -1;
+	} else
+		*c = '\0';
+	safestrcat(path, SYSFS_BUS_NAME);
 	safestrcat(path, "/");
 	safestrcat(path, dev->bus);
 	safestrcat(path, "/");
 	safestrcat(path, SYSFS_DRIVERS_NAME);
 
-	safestrcpy(devpath, dev->path);
-	c = strstr(devpath, SYSFS_DEVICES_NAME);
-	if (c == NULL)
-		return 1;
-	*c = '\0';
-	safestrcatmax(c, path, (sizeof(devpath) - strlen(devpath)));
-
-	drvlist = sysfs_open_subsystem_list(path);
-	if (drvlist != NULL) {
+	drvlist = sysfs_open_directory_list(path);
+	if (drvlist) {
 		dlist_for_each_data(drvlist, drv, char) {
-			safestrcpy(path, devpath);
-			safestrcat(path, "/");
-			safestrcat(path, drv);
-			safestrcat(path, "/");
-			safestrcat(path, dev->bus_id);
-			if (sysfs_path_is_link(path) == 0) {
+			safestrcpy(devpath, path);
+			safestrcat(devpath, "/");
+			safestrcat(devpath, drv);
+			safestrcat(devpath, "/");
+			safestrcat(devpath, dev->bus_id);
+			if (sysfs_path_is_link(devpath) == 0) {
 				safestrcpy(dev->driver_name, drv);
 				sysfs_close_list(drvlist);
 				return 0;
@@ -73,35 +89,9 @@ static int get_dev_driver(struct sysfs_device *dev)
 		}
 		sysfs_close_list(drvlist);
 	}
-	return 1;
+	return -1;
 }
 
-/*
- * get_device_driver_name: gets device's driver name, searches for driver
- *	link first before going the brute force route.
- * @dev: device to retrieve driver
- * returns 0 with success and 1 with error
- */
-static int get_device_driver_name(struct sysfs_device *dev)
-{
-	char devpath[SYSFS_PATH_MAX], drvpath[SYSFS_PATH_MAX];
-
-	if (dev == NULL) {
-		errno = EINVAL;
-		return 1;
-	}
-	memset(devpath, 0, SYSFS_PATH_MAX);
-	memset(drvpath, 0, SYSFS_PATH_MAX);
-	safestrcpy(devpath, dev->path);
-	safestrcat(devpath, "/driver");
-
-	if ((sysfs_get_link(devpath, drvpath, SYSFS_PATH_MAX)) != 0) 
-		return(get_dev_driver(dev));
-
-	return (sysfs_get_name_from_path(drvpath, dev->driver_name, 
-		SYSFS_NAME_LEN));
-}
-	
 /**
  * sysfs_get_device_bus: retrieves the bus name the device is on, checks path 
  * 	to bus' link to make sure it has correct device.
@@ -110,31 +100,49 @@ static int get_device_driver_name(struct sysfs_device *dev)
  */
 int sysfs_get_device_bus(struct sysfs_device *dev)
 {
-	char subsys[SYSFS_NAME_LEN], path[SYSFS_PATH_MAX];
-	char target[SYSFS_PATH_MAX], *bus = NULL, *c = NULL;
-	struct dlist *buslist = NULL;
+	char devpath[SYSFS_PATH_MAX];
+	char subsys[SYSFS_NAME_LEN];
+	char path[SYSFS_PATH_MAX];
+	char target[SYSFS_PATH_MAX];
+	char *bus = NULL, *c;
+	struct dlist *buslist;
 
-	if (dev == NULL) {
+	if (!dev) {
 		errno = EINVAL;
 		return -1;
 	}
 
+	memset(path, 0, SYSFS_PATH_MAX);
+	memset(devpath, 0, SYSFS_PATH_MAX);
+	safestrcpymax(path, dev->path, SYSFS_PATH_MAX);
+	safestrcatmax(path, "/bus", SYSFS_PATH_MAX);
+	if (!sysfs_path_is_link(path)) {
+		if (!sysfs_get_link(path, devpath, SYSFS_PATH_MAX)) {
+			if (sysfs_get_name_from_path(devpath, 
+					dev->bus, SYSFS_NAME_LEN))
+				return -1;
+		}
+		return 0;
+	}
+
+	/*
+	 * Devices on on earlier kernels do not have the "bus" link.
+	 * Look it up in the bus directory.
+	 */
 	memset(subsys, 0, SYSFS_NAME_LEN);
-	safestrcpy(subsys, SYSFS_BUS_NAME);  /* subsys = bus */
-	buslist = sysfs_open_subsystem_list(subsys);
-	if (buslist != NULL) {
+	safestrcpy(subsys, dev->path);
+	c = strstr(subsys, SYSFS_DEVICES_NAME);
+	if (c == NULL) {
+		dprintf("Invalid path to device - %s\n", dev->path);
+		return -1;
+	} else 
+		*c = '\0';
+	safestrcat(subsys, SYSFS_BUS_NAME);
+	buslist = sysfs_open_directory_list(subsys);
+	if (buslist) {
 		dlist_for_each_data(buslist, bus, char) {
 			memset(path, 0, SYSFS_PATH_MAX);
-			safestrcpy(path, dev->path);
-			c = strstr(path, "/devices");
-			if (c == NULL) {
-				dprintf("Invalid path to device %s\n", path);
-				sysfs_close_list(buslist);
-				return -1;
-			}
-			*c = '\0';
-			safestrcat(path, "/");
-			safestrcat(path, SYSFS_BUS_NAME);
+			safestrcpy(path, subsys);
 			safestrcat(path, "/");
 			safestrcat(path, bus);
 			safestrcat(path, "/");
@@ -143,8 +151,8 @@ int sysfs_get_device_bus(struct sysfs_device *dev)
 			safestrcat(path, dev->bus_id);
 			if ((sysfs_path_is_link(path)) == 0) {
 				memset(target, 0, SYSFS_PATH_MAX);
-				if ((sysfs_get_link(path, target, 
-						SYSFS_PATH_MAX)) != 0) {
+				if (sysfs_get_link(path, target, 
+						SYSFS_PATH_MAX)) {
 					dprintf("Error getting link target\n");
 					sysfs_close_list(buslist);
 					return -1;
@@ -156,10 +164,10 @@ int sysfs_get_device_bus(struct sysfs_device *dev)
 					return 0;
 				}
 			}
-                }
-                sysfs_close_list(buslist);
-        }
-        return -1;
+		}
+		sysfs_close_list(buslist);
+	}
+	return -1;
 }
 
 /**
@@ -169,8 +177,8 @@ int sysfs_get_device_bus(struct sysfs_device *dev)
  */
 void sysfs_close_device_tree(struct sysfs_device *devroot)
 {
-	if (devroot != NULL) {
-		if (devroot->children != NULL) {
+	if (devroot) {
+		if (devroot->children) {
 			struct sysfs_device *child = NULL;
 
 			dlist_for_each_data(devroot->children, child,
@@ -182,27 +190,19 @@ void sysfs_close_device_tree(struct sysfs_device *devroot)
 	}
 }
 
-/**
- * sysfs_close_dev_tree: routine for dlist integration
- */
-static void sysfs_close_dev_tree(void *dev)
-{
-	sysfs_close_device_tree((struct sysfs_device *)dev);
-}
-
 /**
  * sysfs_close_device: closes and cleans up a device
  * @dev = device to clean up
  */
 void sysfs_close_device(struct sysfs_device *dev)
 {
-	if (dev != NULL) {
-		if (dev->parent != NULL)
+	if (dev) {
+		if (dev->parent)
 			sysfs_close_device(dev->parent);
-		if (dev->directory != NULL)
-			sysfs_close_directory(dev->directory);
-		if (dev->children != NULL && dev->children->count == 0)
+		if (dev->children && dev->children->count)
 			dlist_destroy(dev->children);
+		if (dev->attrlist)
+			dlist_destroy(dev->attrlist);
 		free(dev);
 	}
 }
@@ -213,36 +213,7 @@ void sysfs_close_device(struct sysfs_device *dev)
  */
 static struct sysfs_device *alloc_device(void)
 {
-	return (struct sysfs_device *)calloc(1, sizeof(struct sysfs_device));
-}
-
-/**
- * open_device_dir: opens up sysfs_directory for specific root dev
- * @name: name of root
- * returns struct sysfs_directory with success and NULL with error
- */
-static struct sysfs_directory *open_device_dir(const char *path)
-{
-	struct sysfs_directory *rdir = NULL;
-
-	if (path == NULL) {
-		errno = EINVAL;
-		return NULL;
-	}
-
-	rdir = sysfs_open_directory(path);
-	if (rdir == NULL) {
-		errno = EINVAL;
-		dprintf ("Device %s not supported on this system\n", path);
-		return NULL;
-	}
-	if ((sysfs_read_dir_subdirs(rdir)) != 0) {
-		dprintf ("Error reading device at dir %s\n", path);
-		sysfs_close_directory(rdir);
-		return NULL;
-	}
-	
-	return rdir;
+	return (struct sysfs_device *) calloc(1, sizeof(struct sysfs_device));
 }
 
 /**
@@ -252,45 +223,44 @@ static struct sysfs_directory *open_device_dir(const char *path)
  */
 struct sysfs_device *sysfs_open_device_path(const char *path)
 {
-	struct sysfs_device *dev = NULL;
+	struct sysfs_device *dev;
 
-	if (path == NULL) {
+	if (!path) {
 		errno = EINVAL;
 		return NULL;
 	}
-	if ((sysfs_path_is_dir(path)) != 0) {
+	if (sysfs_path_is_dir(path)) {
 		dprintf("Incorrect path to device: %s\n", path);
 		return NULL;
 	}
-	dev = alloc_device();	
-	if (dev == NULL) {
+	dev = alloc_device();
+	if (!dev) {
 		dprintf("Error allocating device at %s\n", path);
 		return NULL;
 	}
-	if ((sysfs_get_name_from_path(path, dev->bus_id, 
-					SYSFS_NAME_LEN)) != 0) {
+	if (sysfs_get_name_from_path(path, dev->bus_id, SYSFS_NAME_LEN)) {
 		errno = EINVAL;
 		dprintf("Error getting device bus_id\n");
 		sysfs_close_device(dev);
 		return NULL;
 	}
 	safestrcpy(dev->path, path);
-	if ((sysfs_remove_trailing_slash(dev->path)) != 0) {
+	if (sysfs_remove_trailing_slash(dev->path)) {
 		dprintf("Invalid path to device %s\n", dev->path);
 		sysfs_close_device(dev);
 		return NULL;
 	}
-	/* 
+	/*
 	 * The "name" attribute no longer exists... return the device's
 	 * sysfs representation instead, in the "dev->name" field, which
 	 * implies that the dev->name and dev->bus_id contain same data.
 	 */
 	safestrcpy(dev->name, dev->bus_id);
-	
-	if (sysfs_get_device_bus(dev) != 0)
+
+	if (sysfs_get_device_bus(dev))
 		dprintf("Could not get device bus\n");
-	
-	if (get_device_driver_name(dev) != 0) {
+
+	if (get_dev_driver(dev)) {
 		dprintf("Could not get device %s's driver\n", dev->bus_id);
 		safestrcpy(dev->driver_name, SYSFS_UNKNOWN);
 	}
@@ -299,227 +269,33 @@ struct sysfs_device *sysfs_open_device_path(const char *path)
 }
 
 /**
- * sysfs_open_device_tree: opens root device and all of its children,
- *	creating a tree of devices. Only opens children.
- * @path: sysfs path to devices
- * returns struct sysfs_device and its children with success or NULL with
- *	error.
- */
-struct sysfs_device *sysfs_open_device_tree(const char *path)
-{
-	struct sysfs_device *rootdev = NULL, *new = NULL;
-	struct sysfs_directory *cur = NULL;
-
-	if (path == NULL) {
-		errno = EINVAL;
-		return NULL;
-	}
-	rootdev = sysfs_open_device_path(path);
-	if (rootdev == NULL) {
-		dprintf("Error opening root device at %s\n", path);
-		return NULL;
-	}
-	if (rootdev->directory == NULL) {
-		rootdev->directory = open_device_dir(rootdev->path);
-		if (rootdev->directory == NULL) 
-			return NULL;
-	}
-	if (rootdev->directory->subdirs != NULL) {
-		dlist_for_each_data(rootdev->directory->subdirs, cur,
-				struct sysfs_directory) {
-			new = sysfs_open_device_tree(cur->path);
-			if (new == NULL) {
-				dprintf("Error opening device tree at %s\n",
-					cur->path);
-				sysfs_close_device_tree(rootdev);
-				return NULL;
-			}
-			if (rootdev->children == NULL)
-				rootdev->children = dlist_new_with_delete
-					(sizeof(struct sysfs_device),
-					sysfs_close_dev_tree);
-			dlist_unshift_sorted(rootdev->children, 
-							new, sort_list);
-		}
-	}
-
-	return rootdev;
-}
-
-/**
- * sysfs_close_root_device: closes root and all devices
- * @root: root device to close
- */
-void sysfs_close_root_device(struct sysfs_root_device *root)
-{
-	if (root != NULL) {
-		if (root->devices != NULL)
-			dlist_destroy(root->devices);
-		if (root->directory != NULL)
-			sysfs_close_directory(root->directory);
-		free(root);
-	}
-}
-
-/**
- * sysfs_get_root_devices: opens up all the devices under this root device
- * @root: root device to open devices for
- * returns dlist of devices with success and NULL with error
- */
-struct dlist *sysfs_get_root_devices(struct sysfs_root_device *root)
-{
-	struct sysfs_device *dev = NULL;
-	struct sysfs_directory *cur = NULL;
-
-	if (root == NULL) {
-		errno = EINVAL;
-		return NULL;
-	}
-	if (root->directory == NULL) {
-		root->directory = open_device_dir(root->path);
-		if (root->directory == NULL)
-			return NULL;
-	}
-		
-	if (root->directory->subdirs == NULL)
-		return 0;
-
-	dlist_for_each_data(root->directory->subdirs, cur,
-			struct sysfs_directory) {
-		dev = sysfs_open_device_tree(cur->path);
-		if (dev == NULL) {
-			dprintf ("Error opening device at %s\n", cur->path);
-			continue;
-		}
-		if (root->devices == NULL)
-			root->devices = dlist_new_with_delete
-				(sizeof(struct sysfs_device), 
-				sysfs_close_dev_tree);
-		dlist_unshift_sorted(root->devices, dev, sort_list);
-	}
-
-	return root->devices;
-}
-
-/**
- * sysfs_open_root_device: opens sysfs devices root and all of its
- *	devices.
- * @name: name of /sys/devices/root to open
- * returns struct sysfs_root_device if success and NULL with error
- */
-struct sysfs_root_device *sysfs_open_root_device(const char *name)
-{
-	struct sysfs_root_device *root = NULL;
-	char rootpath[SYSFS_PATH_MAX];
-
-	if (name == NULL) {
-		errno = EINVAL;
-		return NULL;
-	}
-
-	memset(rootpath, 0, SYSFS_PATH_MAX);
-	if (sysfs_get_mnt_path(rootpath, SYSFS_PATH_MAX) != 0) {
-		dprintf ("Sysfs not supported on this system\n");
-		return NULL;
-	}
-
-	safestrcat(rootpath, "/");
-	safestrcat(rootpath, SYSFS_DEVICES_NAME);
-	safestrcat(rootpath, "/");
-	safestrcat(rootpath, name);
-	if ((sysfs_path_is_dir(rootpath)) != 0) {
-		errno = EINVAL;
-		dprintf("Invalid root device: %s\n", name);
-		return NULL;
-	}
-	root = (struct sysfs_root_device *)calloc
-					(1, sizeof(struct sysfs_root_device));
-	if (root == NULL) {
-		dprintf("calloc failure\n");
-		return NULL;
-	}
-	safestrcpy(root->name, name);
-	safestrcpy(root->path, rootpath);
-	if ((sysfs_remove_trailing_slash(root->path)) != 0) {
-		dprintf("Invalid path to root device %s\n", root->path);
-		sysfs_close_root_device(root);
-		return NULL;
-	}
-	return root;
-}
-
-/**
- * sysfs_get_device_attributes: returns a dlist of attributes corresponding to
- * 	the specific device
- * @device: struct sysfs_device * for which attributes are to be returned
- */
-struct dlist *sysfs_get_device_attributes(struct sysfs_device *device)
-{
-	if (device == NULL) {
-		errno = EINVAL;
-		return NULL;
-	}
-
-	if (device->directory == NULL) {
-		device->directory = sysfs_open_directory(device->path);
-		if (device->directory == NULL) 
-			return NULL;
-	}
-	if (device->directory->attributes == NULL) {
-		if ((sysfs_read_dir_attributes(device->directory)) != 0)
-			return NULL;
-	}
-	return (device->directory->attributes);
-}
-
-/**
- * sysfs_refresh_device_attributes: refreshes the device's list of attributes
- * @device: sysfs_device whose attributes to refresh
- *  
- * NOTE: Upon return, prior references to sysfs_attributes for this device
- * 		_may_ not be valid
- *
- * Returns list of attributes on success and NULL on failure
+ * sysfs_get_device_attr: searches dev's attributes by name
+ * @dev: device to look through
+ * @name: attribute name to get
+ * returns sysfs_attribute reference with success or NULL with error.
  */
-struct dlist *sysfs_refresh_device_attributes(struct sysfs_device *device)
+struct sysfs_attribute *sysfs_get_device_attr(struct sysfs_device *dev,
+						const char *name)
 {
-	if (device == NULL) {
+	if (!dev || !name) {
 		errno = EINVAL;
 		return NULL;
 	}
-
-	if (device->directory == NULL)
-		return (sysfs_get_device_attributes(device));
-
-	if ((sysfs_refresh_dir_attributes(device->directory)) != 0) {
-		dprintf("Error refreshing device attributes\n");
-		return NULL;
-	}
-
-	return (device->directory->attributes);
+	return get_attribute(dev, (char *)name);
 }
 
 /**
- * sysfs_get_device_attr: searches dev's attributes by name
- * @dev: device to look through
- * @name: attribute name to get
- * returns sysfs_attribute reference with success or NULL with error.
+ * sysfs_get_device_attributes: gets list of device attributes
+ * @dev: device whose attributes list is needed
+ * returns dlist of attributes on success or NULL on error
  */
-struct sysfs_attribute *sysfs_get_device_attr(struct sysfs_device *dev,
-						const char *name)
+struct dlist *sysfs_get_device_attributes(struct sysfs_device *dev)
 {
-	struct dlist *attrlist = NULL;
-
-	if (dev == NULL || name == NULL) {
+	if (!dev) {
 		errno = EINVAL;
 		return NULL;
 	}
-	
-	attrlist = sysfs_get_device_attributes(dev);
-	if (attrlist == NULL)
-		return NULL;
-
-	return sysfs_get_directory_attribute(dev->directory, (char *)name);
+	return get_attributes_list(dev);
 }
 
 /**
@@ -535,13 +311,13 @@ static int get_device_absolute_path(const char *device,	const char *bus,
 {
 	char bus_path[SYSFS_PATH_MAX];
 
-	if (device == NULL || path == NULL) {
+	if (!device || !path) {
 		errno = EINVAL;
 		return -1;
 	}
 
 	memset(bus_path, 0, SYSFS_PATH_MAX);
-	if (sysfs_get_mnt_path(bus_path, SYSFS_PATH_MAX) != 0) {
+	if (sysfs_get_mnt_path(bus_path, SYSFS_PATH_MAX)) {
 		dprintf ("Sysfs not supported on this system\n");
 		return -1;
 	}
@@ -557,7 +333,7 @@ static int get_device_absolute_path(const char *device,	const char *bus,
 	 * We now are at /sys/bus/"bus_name"/devices/"device" which is a link.
 	 * Now read this link to reach to the device.
 	 */ 
-	if ((sysfs_get_link(bus_path, path, psize)) != 0) {
+	if (sysfs_get_link(bus_path, path, psize)) {
 		dprintf("Error getting to device %s\n", device);
 		return -1;
 	}
@@ -578,21 +354,21 @@ static int get_device_absolute_path(const char *device,	const char *bus,
 struct sysfs_device *sysfs_open_device(const char *bus,	const char *bus_id)
 {
 	char sysfs_path[SYSFS_PATH_MAX];
-	struct sysfs_device *device = NULL;
+	struct sysfs_device *device;
 
-	if (bus_id == NULL || bus == NULL) {
+	if (!bus_id || !bus) {
 		errno = EINVAL;
 		return NULL;
 	}
 	memset(sysfs_path, 0, SYSFS_PATH_MAX);
-	if ((get_device_absolute_path(bus_id, bus, sysfs_path, 
-						SYSFS_PATH_MAX)) != 0) {
+	if (get_device_absolute_path(bus_id, bus, sysfs_path, 
+				SYSFS_PATH_MAX)) {
 		dprintf("Error getting to device %s\n", bus_id);
 		return NULL;
 	}
 	
 	device = sysfs_open_device_path(sysfs_path);
-	if (device == NULL) {
+	if (!device) {
 		dprintf("Error opening device %s\n", bus_id);
 		return NULL;
 	}
@@ -608,20 +384,20 @@ struct sysfs_device *sysfs_open_device(const char *bus,	const char *bus_id)
  */
 struct sysfs_device *sysfs_get_device_parent(struct sysfs_device *dev)
 {
-	char ppath[SYSFS_PATH_MAX], *tmp = NULL;
+	char ppath[SYSFS_PATH_MAX], *tmp;
 
-	if (dev == NULL) {
+	if (!dev) {
 		errno = EINVAL;
 		return NULL;
 	}
 
-	if (dev->parent != NULL)
+	if (dev->parent)
 		return (dev->parent);
 
 	memset(ppath, 0, SYSFS_PATH_MAX);
 	safestrcpy(ppath, dev->path);
 	tmp = strrchr(ppath, '/');
-	if (tmp == NULL) {
+	if (!tmp) {
 		dprintf("Invalid path to device %s\n", ppath);
 		return NULL;
 	}
@@ -634,68 +410,22 @@ struct sysfs_device *sysfs_get_device_parent(struct sysfs_device *dev)
 		}
 	}
 	*tmp = '\0';
-	
+
 	/*
 	 * All "devices" have the "detach_state" attribute - validate here
 	 */
 	safestrcat(ppath, "/detach_state");
-	if ((sysfs_path_is_file(ppath)) != 0) {
+	if (sysfs_path_is_file(ppath)) {
 		dprintf("Device at %s does not have a parent\n", dev->path);
 		return NULL;
 	}
 	tmp = strrchr(ppath, '/');
 	*tmp = '\0';
 	dev->parent = sysfs_open_device_path(ppath);
-	if (dev->parent == NULL) {
+	if (!dev->parent) {
 		dprintf("Error opening device %s's parent at %s\n", 
 					dev->bus_id, ppath);
 		return NULL;
 	}
 	return (dev->parent);
 }
-
-/*
- * sysfs_open_device_attr: open the given device's attribute
- * @bus: Bus on which to look
- * @dev_id: device for which attribute is required
- * @attrname: name of the attribute to look for
- * Returns struct sysfs_attribute on success and NULL on failure
- * 
- * NOTE:
- * 	A call to sysfs_close_attribute() is required to close
- * 	the attribute returned and free memory. 
- */
-struct sysfs_attribute *sysfs_open_device_attr(const char *bus,
-		const char *bus_id, const char *attrib)
-{
-	struct sysfs_attribute *attribute = NULL;
-	char devpath[SYSFS_PATH_MAX];
-	
-	if (bus == NULL || bus_id == NULL || attrib == NULL) {
-		errno = EINVAL;
-		return NULL;
-	}
-
-	memset(devpath, 0, SYSFS_PATH_MAX);
-	if ((get_device_absolute_path(bus_id, bus, devpath, 
-					SYSFS_PATH_MAX)) != 0) {
-		dprintf("Error getting to device %s\n", bus_id);
-		return NULL;
-	}
-	safestrcat(devpath, "/");
-	safestrcat(devpath, attrib);
-	attribute = sysfs_open_attribute(devpath);
-	if (attribute == NULL) {
-		dprintf("Error opening attribute %s for device %s\n",
-				attrib, bus_id);
-		return NULL;
-	}
-	if ((sysfs_read_attribute(attribute)) != 0) {
-		dprintf("Error reading attribute %s for device %s\n",
-				attrib, bus_id);
-		sysfs_close_attribute(attribute);
-		return NULL;
-	}
-	return attribute;
-}
-