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, 8 insertions, 27 deletions

diff --git a/block/genhd.c b/block/genhd.c
index 3af1e7a378d4..e609996f2e76 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -540,61 +540,42 @@ static int block_uevent_filter(struct kset *kset, struct kobject *kobj)
         return ((ktype == &ktype_block) || (ktype == &ktype_part));
 }
 
-static int block_uevent(struct kset *kset, struct kobject *kobj, char **envp,
-                         int num_envp, char *buffer, int buffer_size)
+static int block_uevent(struct kset *kset, struct kobject *kobj,
+                        struct kobj_uevent_env *env)
 {
         struct kobj_type *ktype = get_ktype(kobj);
         struct device *physdev;
         struct gendisk *disk;
         struct hd_struct *part;
-        int length = 0;
-        int i = 0;
 
         if (ktype == &ktype_block) {
                 disk = container_of(kobj, struct gendisk, kobj);
-                add_uevent_var(envp, num_envp, &i, buffer, buffer_size,
-                               &length, "MINOR=%u", disk->first_minor);
+                add_uevent_var(env, "MINOR=%u", disk->first_minor);
         } else if (ktype == &ktype_part) {
                 disk = container_of(kobj->parent, struct gendisk, kobj);
                 part = container_of(kobj, struct hd_struct, kobj);
-                add_uevent_var(envp, num_envp, &i, buffer, buffer_size,
-                               &length, "MINOR=%u",
+                add_uevent_var(env, "MINOR=%u",
                                disk->first_minor + part->partno);
         } else
                 return 0;
 
-        add_uevent_var(envp, num_envp, &i, buffer, buffer_size, &length,
-                       "MAJOR=%u", disk->major);
+        add_uevent_var(env, "MAJOR=%u", disk->major);
 
         /* add physical device, backing this device  */
         physdev = disk->driverfs_dev;
         if (physdev) {
                 char *path = kobject_get_path(&physdev->kobj, GFP_KERNEL);
 
-                add_uevent_var(envp, num_envp, &i, buffer, buffer_size,
-                               &length, "PHYSDEVPATH=%s", path);
+                add_uevent_var(env, "PHYSDEVPATH=%s", path);
                 kfree(path);
 
                 if (physdev->bus)
-                        add_uevent_var(envp, num_envp, &i,
-                                       buffer, buffer_size, &length,
-                                       "PHYSDEVBUS=%s",
-                                       physdev->bus->name);
+                        add_uevent_var(env, "PHYSDEVBUS=%s", physdev->bus->name);
 
                 if (physdev->driver)
-                        add_uevent_var(envp, num_envp, &i,
-                                       buffer, buffer_size, &length,
-                                       "PHYSDEVDRIVER=%s",
-                                       physdev->driver->name);
+                        add_uevent_var(env, physdev->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;
-
         return 0;
 }