[PATCH] pre-libsysfs-0.4.0 patch

I am sending you a pre-release patch. It's everything that's in our
current CVS tree. It adds the functionality you've been looking for. Please
play with this before checking it into your tree, I'd like to know if
it's ok with you or if you find problems. I have tested this out with
test.all and the perl regression test. Let me know what you think.

Still need to do more testing for our work and add some more functions
related to the changes.

I've gone into namedev.c and udev-add.c to make the necessary changes
in line with the library. I have not gone and edited any of the "extras".


Changes:

1) Libsysfs object structures work more as handles now, their included
directories or devices are labeled private. If you need attributes
from a sysfs_class_device, call the available function and don't access
the directory directly. Same holds true for a sysfs_class_device
sysfs_device. Do not access the link directly but call the function
sysfs_get_classdev_device() instead. We only populate entries upon
request, makes things faster and uses less memory.

2) Added sysfs_get_classdev_parent() as requested.

3) Changed getpagesize to sysconf.

4) Added sysfs_refresh_attributes function for refreshing views of
attribute lists. We still need to add refresh for links and subdirs. All
udev needs to do is keep calling sysfs_get_classdev_attr() and that will
internally call the refresh routine.

1 files changed, 283 insertions, 141 deletions

diff --git a/libsysfs/sysfs_class.c b/libsysfs/sysfs_class.c
index 54f22eee24..169600d5fd 100644
--- a/libsysfs/sysfs_class.c
+++ b/libsysfs/sysfs_class.c
@@ -58,6 +58,8 @@ 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);
 	}
 }
@@ -96,54 +98,6 @@ 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;
-	}
-
-	if (sysfs_trailing_slash(classpath) == 0)
-		strcat(classpath, "/");
-	/* 
-	 * 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_NAME);
-	} else {
-		strcat(classpath, SYSFS_CLASS_NAME);
-		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
@@ -154,20 +108,18 @@ static void set_classdev_classname(struct sysfs_class_device *cdev)
 	unsigned 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 = strstr(c, "/");
 	}
 
-	if (c == NULL) 
+	if (c == NULL)
 		strcpy(cdev->classname, SYSFS_UNKNOWN);
-
 	else {
-		c++;
+		if (*c == '/')
+			c++;
 		e = c;
 		while (e != NULL && *e != '/' && *e != '\0') {
 			e++;
@@ -185,15 +137,15 @@ static void set_classdev_classname(struct sysfs_class_device *cdev)
 struct sysfs_class_device *sysfs_open_class_device(const unsigned 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");
@@ -201,81 +153,41 @@ 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);
-		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);
+	strcpy(cdev->path, 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
+ * sysfs_get_class_devices: gets all devices for class
  * @class: class to get devices for
- * returns 0 with success and -1 with failure
+ * 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;
+	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) 
+	    || cls->directory->subdirs == NULL)
+		return NULL;
+
 	dlist_for_each_data(cls->directory->subdirs, cur, 
 			struct sysfs_directory) {
 		dev = sysfs_open_class_device(cur->path);
@@ -289,7 +201,7 @@ static int get_all_class_devices(struct sysfs_class *cls)
 					 		sysfs_close_cls_dev);
 		dlist_unshift(cls->devices, dev);
 	}
-	return 0;
+	return cls->devices;
 }
 
 /**
@@ -299,34 +211,46 @@ static int get_all_class_devices(struct sysfs_class *cls)
 struct sysfs_class *sysfs_open_class(const unsigned char *name)
 {
 	struct sysfs_class *cls = NULL;
-	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;
+        }
+
+	if (sysfs_trailing_slash(classpath) == 0)
+		strcat(classpath, "/");
+
+	/* 
+	 * 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_NAME);
+	} else {
+		strcat(classpath, SYSFS_CLASS_NAME);
+		strcat(classpath, "/");
+		strcat(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);
-		sysfs_close_class(cls);
-		return NULL;
-	}
-
+	strcpy(cls->path, classpath);
+	
 	return cls;
 }
 
@@ -338,16 +262,190 @@ struct sysfs_class *sysfs_open_class(const unsigned char *name)
 struct sysfs_class_device *sysfs_get_class_device(struct sysfs_class *class,
 					unsigned char *name)
 {
+	struct dlist *devlist = NULL;
+	
 	if (class == NULL || name == NULL) {
 		errno = EINVAL;
 		return NULL;
 	}
 
+	if (class->devices == NULL) {
+		class->devices = sysfs_get_class_devices(class);
+		if (devlist == NULL) 
+			return NULL;
+	}
 	return (struct sysfs_class_device *)dlist_find_custom(class->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;
+	
+	if (clsdev == NULL) {
+		errno = EINVAL;
+		return NULL;
+	}
+	
+	if (clsdev->sysdevice != NULL)
+		return (clsdev->sysdevice);
+	
+	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) 
+		return NULL;
+
+	clsdev->sysdevice = sysfs_open_device(devlink->target);
+	if (clsdev->sysdevice == NULL)
+		return NULL;
+	if (clsdev->driver != NULL) 
+		strcpy(clsdev->sysdevice->driver_name, clsdev->driver->name);
+
+	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;
+	
+	if (clsdev == NULL) {
+		errno = EINVAL;
+		return NULL;
+	}
+	
+	if (clsdev->driver != NULL)
+		return (clsdev->driver);
+	
+	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) {
+		clsdev->driver = sysfs_open_driver(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)
+{
+	unsigned char parent_path[SYSFS_PATH_MAX], value[256], *c = NULL;
+	
+	memset(parent_path, 0, SYSFS_PATH_MAX);
+	strcpy(parent_path, clsdev->path);
+
+	c = strstr(parent_path, SYSFS_BLOCK_NAME);
+	if (c == NULL) {
+		dprintf("Class device %s does not belong to BLOCK subsystem",
+				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';
+	
+	/* Now validate if the parent has the "dev" attribute */
+	memset(value, 0, 256);
+	strcat(parent_path, "/dev");
+	if ((sysfs_read_attribute_value(parent_path, value, 256)) != 0) {
+		dprintf("Block device %s does not have a parent\n", 
+							clsdev->name);
+		return 1;
+	}
+		
+	c = strrchr(parent_path, '/');
+	if (c == NULL)
+		goto errout;
+
+	*c = '\0';
+	clsdev->parent = sysfs_open_class_device(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 (!(strcmp(clsdev->classname, 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
  * @classname: name of the class
@@ -367,6 +465,7 @@ static int get_classdev_path(const unsigned char *classname,
                 dprintf("Error getting sysfs mount path\n");
                 return -1;
 	}
+
 	if (sysfs_trailing_slash(path) == 0)
 		strcat(path, "/");
 
@@ -427,9 +526,32 @@ 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) {
+			dprintf("Error reading attributes for directory %s\n",
+							cdev->directory->path);
+			return NULL;
+		}
+	} else {
+		if ((sysfs_path_is_dir(cdev->path)) != 0) {
+			dprintf("Class device at %s no longer exists\n", 
+							cdev->path);
+			return NULL;
+		}
+		if ((sysfs_refresh_attributes
+					(cdev->directory->attributes)) != 0) {
+			dprintf("Error refreshing classdev attributes\n");
+			return NULL;
+		}
+	}
 	return (cdev->directory->attributes);
 }
 
@@ -443,18 +565,38 @@ struct sysfs_attribute *sysfs_get_classdev_attr
 		(struct sysfs_class_device *clsdev, const unsigned 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)
+		return NULL;
 	cur = sysfs_get_directory_attribute(clsdev->directory,
 						(unsigned char *)name);
 	if (cur != NULL)
 		return cur;
 
+	if (clsdev->directory->subdirs == NULL) 
+		if ((sysfs_read_dir_subdirs(clsdev->directory)) != 0 ||
+		    clsdev->directory->subdirs == NULL) 
+			return NULL;
+
+	dlist_for_each_data(clsdev->directory->subdirs, sdir,
+				struct sysfs_directory) {
+		cur = sysfs_get_directory_attribute(sdir, 
+						(unsigned char *)name);
+		if (cur != NULL)
+			return cur;
+	}
+		
 	return NULL;
 }