Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/hid/hid

[linux-2.6-microblaze.git] / fs / sysfs / file.c

diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c
index 130fc6f..26bbf96 100644 (file)
--- a/fs/sysfs/file.c
+++ b/fs/sysfs/file.c
@@ -558,3 +558,151 @@ void sysfs_remove_bin_file(struct kobject *kobj,
        kernfs_remove_by_name(kobj->sd, attr->attr.name);
 }
 EXPORT_SYMBOL_GPL(sysfs_remove_bin_file);
+
+static int internal_change_owner(struct kernfs_node *kn, kuid_t kuid,
+                                kgid_t kgid)
+{
+       struct iattr newattrs = {
+               .ia_valid = ATTR_UID | ATTR_GID,
+               .ia_uid = kuid,
+               .ia_gid = kgid,
+       };
+       return kernfs_setattr(kn, &newattrs);
+}
+
+/**
+ *     sysfs_link_change_owner - change owner of a sysfs file.
+ *     @kobj:  object of the kernfs_node the symlink is located in.
+ *     @targ:  object of the kernfs_node the symlink points to.
+ *     @name:  name of the link.
+ *     @kuid:  new owner's kuid
+ *     @kgid:  new owner's kgid
+ *
+ * This function looks up the sysfs symlink entry @name under @kobj and changes
+ * the ownership to @kuid/@kgid. The symlink is looked up in the namespace of
+ * @targ.
+ *
+ * Returns 0 on success or error code on failure.
+ */
+int sysfs_link_change_owner(struct kobject *kobj, struct kobject *targ,
+                           const char *name, kuid_t kuid, kgid_t kgid)
+{
+       struct kernfs_node *kn = NULL;
+       int error;
+
+       if (!name || !kobj->state_in_sysfs || !targ->state_in_sysfs)
+               return -EINVAL;
+
+       error = -ENOENT;
+       kn = kernfs_find_and_get_ns(kobj->sd, name, targ->sd->ns);
+       if (!kn)
+               goto out;
+
+       error = -EINVAL;
+       if (kernfs_type(kn) != KERNFS_LINK)
+               goto out;
+       if (kn->symlink.target_kn->priv != targ)
+               goto out;
+
+       error = internal_change_owner(kn, kuid, kgid);
+
+out:
+       kernfs_put(kn);
+       return error;
+}
+
+/**
+ *     sysfs_file_change_owner - change owner of a sysfs file.
+ *     @kobj:  object.
+ *     @name:  name of the file to change.
+ *     @kuid:  new owner's kuid
+ *     @kgid:  new owner's kgid
+ *
+ * This function looks up the sysfs entry @name under @kobj and changes the
+ * ownership to @kuid/@kgid.
+ *
+ * Returns 0 on success or error code on failure.
+ */
+int sysfs_file_change_owner(struct kobject *kobj, const char *name, kuid_t kuid,
+                           kgid_t kgid)
+{
+       struct kernfs_node *kn;
+       int error;
+
+       if (!name)
+               return -EINVAL;
+
+       if (!kobj->state_in_sysfs)
+               return -EINVAL;
+
+       kn = kernfs_find_and_get(kobj->sd, name);
+       if (!kn)
+               return -ENOENT;
+
+       error = internal_change_owner(kn, kuid, kgid);
+
+       kernfs_put(kn);
+
+       return error;
+}
+EXPORT_SYMBOL_GPL(sysfs_file_change_owner);
+
+/**
+ *     sysfs_change_owner - change owner of the given object.
+ *     @kobj:  object.
+ *     @kuid:  new owner's kuid
+ *     @kgid:  new owner's kgid
+ *
+ * Change the owner of the default directory, files, groups, and attributes of
+ * @kobj to @kuid/@kgid. Note that sysfs_change_owner mirrors how the sysfs
+ * entries for a kobject are added by driver core. In summary,
+ * sysfs_change_owner() takes care of the default directory entry for @kobj,
+ * the default attributes associated with the ktype of @kobj and the default
+ * attributes associated with the ktype of @kobj.
+ * Additional properties not added by driver core have to be changed by the
+ * driver or subsystem which created them. This is similar to how
+ * driver/subsystem specific entries are removed.
+ *
+ * Returns 0 on success or error code on failure.
+ */
+int sysfs_change_owner(struct kobject *kobj, kuid_t kuid, kgid_t kgid)
+{
+       int error;
+       const struct kobj_type *ktype;
+
+       if (!kobj->state_in_sysfs)
+               return -EINVAL;
+
+       /* Change the owner of the kobject itself. */
+       error = internal_change_owner(kobj->sd, kuid, kgid);
+       if (error)
+               return error;
+
+       ktype = get_ktype(kobj);
+       if (ktype) {
+               struct attribute **kattr;
+
+               /*
+                * Change owner of the default attributes associated with the
+                * ktype of @kobj.
+                */
+               for (kattr = ktype->default_attrs; kattr && *kattr; kattr++) {
+                       error = sysfs_file_change_owner(kobj, (*kattr)->name,
+                                                       kuid, kgid);
+                       if (error)
+                               return error;
+               }
+
+               /*
+                * Change owner of the default groups associated with the
+                * ktype of @kobj.
+                */
+               error = sysfs_groups_change_owner(kobj, ktype->default_groups,
+                                                 kuid, kgid);
+               if (error)
+                       return error;
+       }
+
+       return 0;
+}
+EXPORT_SYMBOL_GPL(sysfs_change_owner);