Kobject Userspace Event Notification

  
Implemetation of userspace events through a netlink socket. The kernel events
layer provides the functionality to raise an event from a given kobject
represented by its sysfs-path and a signal string to describe the type of
event.
  
Currently, kobject additions and removals are signalized to userspace by forking
the /sbin/hotplug helper. This patch moves this special case of userspace-event
out of the kobject core to the new kobject_uevent implementation. This makes it
possible to send all hotplug messages also through the new netlink transport.
  
Possible new users of the kernel userspace functionality are filesystem
mount events (block device claim/release) or simple device state transitions
(cpu overheating).
  
To send an event, the user needs to pass the kobject, a optional
sysfs-attribute and the signal string to the following function:
  
  kobject_uevent(const char *signal,
                 struct kobject *kobj,
                 struct attribute *attr)
  
  Example:
  kobject_uevent("overheating", &cpu->kobj, NULL);
  
The message itself is sent over multicast netlink socket, which makes
it possible for userspace to listen with multiple applications for the same
messages.
  
Signed-off-by: Robert Love <rml@novell.com>
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>

1 files changed, 5 insertions, 128 deletions

diff --git a/lib/kobject.c b/lib/kobject.c
index 3101764ea605..4bc028f1abdf 100644
--- a/lib/kobject.c
+++ b/lib/kobject.c
@@ -63,7 +63,7 @@ static inline struct kobject * to_kobj(struct list_head * entry)
 	return container_of(entry,struct kobject,entry);
 }
 
-static int get_kobj_path_length(struct kset *kset, struct kobject *kobj)
+static int get_kobj_path_length(struct kobject *kobj)
 {
 	int length = 1;
 	struct kobject * parent = kobj;
@@ -79,7 +79,7 @@ static int get_kobj_path_length(struct kset *kset, struct kobject *kobj)
 	return length;
 }
 
-static void fill_kobj_path(struct kset *kset, struct kobject *kobj, char *path, int length)
+static void fill_kobj_path(struct kobject *kobj, char *path, int length)
 {
 	struct kobject * parent;
 
@@ -99,146 +99,24 @@ static void fill_kobj_path(struct kset *kset, struct kobject *kobj, char *path,
  * kobject_get_path - generate and return the path associated with a given kobj
  * and kset pair.  The result must be freed by the caller with kfree().
  *
- * @kset:	kset in question, with which to build the path
  * @kobj:	kobject in question, with which to build the path
  * @gfp_mask:	the allocation type used to allocate the path
  */
-char * kobject_get_path(struct kset *kset, struct kobject *kobj, int gfp_mask)
+char *kobject_get_path(struct kobject *kobj, int gfp_mask)
 {
 	char *path;
 	int len;
 
-	len = get_kobj_path_length(kset, kobj);
+	len = get_kobj_path_length(kobj);
 	path = kmalloc(len, gfp_mask);
 	if (!path)
 		return NULL;
 	memset(path, 0x00, len);
-	fill_kobj_path(kset, kobj, path, len);
+	fill_kobj_path(kobj, path, len);
 
 	return path;
 }
 
-#ifdef CONFIG_HOTPLUG
-
-u64 hotplug_seqnum;
-#define BUFFER_SIZE	1024	/* should be enough memory for the env */
-#define NUM_ENVP	32	/* number of env pointers */
-static spinlock_t sequence_lock = SPIN_LOCK_UNLOCKED;
-
-static void kset_hotplug(const char *action, struct kset *kset,
-			 struct kobject *kobj)
-{
-	char *argv [3];
-	char **envp = NULL;
-	char *buffer = NULL;
-	char *scratch;
-	int i = 0;
-	int retval;
-	char *kobj_path = NULL;
-	char *name = NULL;
-	unsigned long seq;
-
-	/* If the kset has a filter operation, call it. If it returns
-	   failure, no hotplug event is required. */
-	if (kset->hotplug_ops->filter) {
-		if (!kset->hotplug_ops->filter(kset, kobj))
-			return;
-	}
-
-	pr_debug ("%s\n", __FUNCTION__);
-
-	if (!hotplug_path[0])
-		return;
-
-	envp = kmalloc(NUM_ENVP * sizeof (char *), GFP_KERNEL);
-	if (!envp)
-		return;
-	memset (envp, 0x00, NUM_ENVP * sizeof (char *));
-
-	buffer = kmalloc(BUFFER_SIZE, GFP_KERNEL);
-	if (!buffer)
-		goto exit;
-
-	if (kset->hotplug_ops->name)
-		name = kset->hotplug_ops->name(kset, kobj);
-	if (name == NULL)
-		name = kset->kobj.name;
-
-	argv [0] = hotplug_path;
-	argv [1] = name;
-	argv [2] = NULL;
-
-	/* minimal command environment */
-	envp [i++] = "HOME=/";
-	envp [i++] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";
-
-	scratch = buffer;
-
-	envp [i++] = scratch;
-	scratch += sprintf(scratch, "ACTION=%s", action) + 1;
-
-	spin_lock(&sequence_lock);
-	seq = ++hotplug_seqnum;
-	spin_unlock(&sequence_lock);
-
-	envp [i++] = scratch;
-	scratch += sprintf(scratch, "SEQNUM=%ld", seq) + 1;
-
-	kobj_path = kobject_get_path(kset, kobj, GFP_KERNEL);
-	if (!kobj_path)
-		goto exit;
-
-	envp [i++] = scratch;
-	scratch += sprintf (scratch, "DEVPATH=%s", kobj_path) + 1;
-
-	if (kset->hotplug_ops->hotplug) {
-		/* have the kset specific function add its stuff */
-		retval = kset->hotplug_ops->hotplug (kset, kobj,
-				  &envp[i], NUM_ENVP - i, scratch,
-				  BUFFER_SIZE - (scratch - buffer));
-		if (retval) {
-			pr_debug ("%s - hotplug() returned %d\n",
-				  __FUNCTION__, retval);
-			goto exit;
-		}
-	}
-
-	pr_debug ("%s: %s %s %s %s %s %s %s\n", __FUNCTION__, argv[0], argv[1],
-		  envp[0], envp[1], envp[2], envp[3], envp[4]);
-	retval = call_usermodehelper (argv[0], argv, envp, 0);
-	if (retval)
-		pr_debug ("%s - call_usermodehelper returned %d\n",
-			  __FUNCTION__, retval);
-
-exit:
-	kfree(kobj_path);
-	kfree(buffer);
-	kfree(envp);
-	return;
-}
-
-void kobject_hotplug(const char *action, struct kobject *kobj)
-{
-	struct kobject * top_kobj = kobj;
-
-	/* If this kobj does not belong to a kset,
-	   try to find a parent that does. */
-	if (!top_kobj->kset && top_kobj->parent) {
-		do {
-			top_kobj = top_kobj->parent;
-		} while (!top_kobj->kset && top_kobj->parent);
-	}
-
-	if (top_kobj->kset && top_kobj->kset->hotplug_ops)
-		kset_hotplug(action, top_kobj->kset, kobj);
-}
-#else
-void kobject_hotplug(const char *action, struct kobject *kobj)
-{
-	return;
-}
-#endif	/* CONFIG_HOTPLUG */
-
 /**
  *	kobject_init - initialize object.
  *	@kobj:	object in question.
@@ -654,7 +532,6 @@ EXPORT_SYMBOL(kobject_put);
 EXPORT_SYMBOL(kobject_add);
 EXPORT_SYMBOL(kobject_del);
 EXPORT_SYMBOL(kobject_rename);
-EXPORT_SYMBOL(kobject_hotplug);
 
 EXPORT_SYMBOL(kset_register);
 EXPORT_SYMBOL(kset_unregister);