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>

1 files changed, 10 insertions, 32 deletions

diff --git a/drivers/base/class.c b/drivers/base/class.c
index 4d2222618b78..ecd6336bffea 100644
--- a/drivers/base/class.c
+++ b/drivers/base/class.c
@@ -180,8 +180,7 @@ static void class_device_create_release(struct class_device *class_dev)
 
 /* needed to allow these devices to have parent class devices */
 static int class_device_create_uevent(struct class_device *class_dev,
-                                       char **envp, int num_envp,
-                                       char *buffer, int buffer_size)
+                                      struct kobj_uevent_env *env)
 {
         pr_debug("%s called for %s\n", __FUNCTION__, class_dev->class_id);
         return 0;
@@ -403,64 +402,43 @@ static void remove_deprecated_class_device_links(struct class_device *cd)
 { }
 #endif
 
-static int class_uevent(struct kset *kset, struct kobject *kobj, char **envp,
-                         int num_envp, char *buffer, int buffer_size)
+static int class_uevent(struct kset *kset, struct kobject *kobj,
+                        struct kobj_uevent_env *env)
 {
         struct class_device *class_dev = to_class_dev(kobj);
         struct device *dev = class_dev->dev;
-        int i = 0;
-        int length = 0;
         int retval = 0;
 
         pr_debug("%s - name = %s\n", __FUNCTION__, class_dev->class_id);
 
         if (MAJOR(class_dev->devt)) {
-                add_uevent_var(envp, num_envp, &i,
-                               buffer, buffer_size, &length,
-                               "MAJOR=%u", MAJOR(class_dev->devt));
+                add_uevent_var(env, "MAJOR=%u", MAJOR(class_dev->devt));
 
-                add_uevent_var(envp, num_envp, &i,
-                               buffer, buffer_size, &length,
-                               "MINOR=%u", MINOR(class_dev->devt));
+                add_uevent_var(env, "MINOR=%u", MINOR(class_dev->devt));
         }
 
         if (dev) {
                 const char *path = kobject_get_path(&dev->kobj, GFP_KERNEL);
                 if (path) {
-                        add_uevent_var(envp, num_envp, &i,
-                                       buffer, buffer_size, &length,
-                                       "PHYSDEVPATH=%s", path);
+                        add_uevent_var(env, "PHYSDEVPATH=%s", path);
                         kfree(path);
                 }
 
                 if (dev->bus)
-                        add_uevent_var(envp, num_envp, &i,
-                                       buffer, buffer_size, &length,
-                                       "PHYSDEVBUS=%s", dev->bus->name);
+                        add_uevent_var(env, "PHYSDEVBUS=%s", dev->bus->name);
 
                 if (dev->driver)
-                        add_uevent_var(envp, num_envp, &i,
-                                       buffer, buffer_size, &length,
-                                       "PHYSDEVDRIVER=%s", dev->driver->name);
+                        add_uevent_var(env, "PHYSDEVDRIVER=%s", dev->driver->name);
         }
 
-        /* terminate, set to next free slot, shrink available space */
-        envp[i] = NULL;
-        envp = &envp[i];
-        num_envp -= i;
-        buffer = &buffer[length];
-        buffer_size -= length;
-
         if (class_dev->uevent) {
                 /* have the class device specific function add its stuff */
-                retval = class_dev->uevent(class_dev, envp, num_envp,
-                                            buffer, buffer_size);
+                retval = class_dev->uevent(class_dev, env);
                 if (retval)
                         pr_debug("class_dev->uevent() returned %d\n", retval);
         } else if (class_dev->class->uevent) {
                 /* have the class specific function add its stuff */
-                retval = class_dev->class->uevent(class_dev, envp, num_envp,
-                                                   buffer, buffer_size);
+                retval = class_dev->class->uevent(class_dev, env);
                 if (retval)
                         pr_debug("class->uevent() returned %d\n", retval);
         }