Driver core: change add_uevent_var to use a struct

This changes the uevent buffer functions to use a struct instead of a
long list of parameters. It does no longer require the caller to do the
proper buffer termination and size accounting, which is currently wrong
in some places. It fixes a known bug where parts of the uevent
environment are overwritten because of wrong index calculations.

Many thanks to Mathieu Desnoyers for finding bugs and improving the
error handling.

Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>


diff --git a/drivers/base/firmware_class.c b/drivers/base/firmware_class.c
index b24efd4..4a1b9bf 100644
--- a/drivers/base/firmware_class.c
+++ b/drivers/base/firmware_class.c
@@ -88,19 +88,14 @@
 
 static void fw_dev_release(struct device *dev);
 
-static int firmware_uevent(struct device *dev, char **envp, int num_envp,
-			   char *buffer, int buffer_size)
+static int firmware_uevent(struct device *dev, struct kobj_uevent_env *env)
 {
 	struct firmware_priv *fw_priv = dev_get_drvdata(dev);
-	int i = 0, len = 0;
 
-	if (add_uevent_var(envp, num_envp, &i, buffer, buffer_size, &len,
-			   "FIRMWARE=%s", fw_priv->fw_id))
+	if (add_uevent_var(env, "FIRMWARE=%s", fw_priv->fw_id))
 		return -ENOMEM;
-	if (add_uevent_var(envp, num_envp, &i, buffer, buffer_size, &len,
-			   "TIMEOUT=%i", loading_timeout))
+	if (add_uevent_var(env, "TIMEOUT=%i", loading_timeout))
 		return -ENOMEM;
-	envp[i] = NULL;
 
 	return 0;
 }