[PATCH 4/5] driver core: set up ownership of class devices in sysfs

From: Dmitry Torokhov
Date: Tue Aug 16 2016 - 18:35:02 EST


Plumb in get_ownership() callback for devices belonging to a class so that
they can be created with uid/gid different from global root. This will
allow network devices in a container to belong to container's root and not
global root.

Signed-off-by: Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx>
---
drivers/base/core.c | 9 +++++++++
include/linux/device.h | 5 +++++
2 files changed, 14 insertions(+)

diff --git a/drivers/base/core.c b/drivers/base/core.c
index 0a8bdad..0f95454 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -263,10 +263,19 @@ static const void *device_namespace(struct kobject *kobj)
return ns;
}

+static void device_get_ownership(struct kobject *kobj, kuid_t *uid, kgid_t *gid)
+{
+ struct device *dev = kobj_to_dev(kobj);
+
+ if (dev->class && dev->class->get_ownership)
+ dev->class->get_ownership(dev, uid, gid);
+}
+
static struct kobj_type device_ktype = {
.release = device_release,
.sysfs_ops = &dev_sysfs_ops,
.namespace = device_namespace,
+ .get_ownership = device_get_ownership,
};


diff --git a/include/linux/device.h b/include/linux/device.h
index 38f0281..da20b12 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -374,6 +374,9 @@ int subsys_virtual_register(struct bus_type *subsys,
* @resume: Used to bring the device from the sleep mode.
* @ns_type: Callbacks so sysfs can detemine namespaces.
* @namespace: Namespace of the device belongs to this class.
+ * @get_ownership: Allows class to specify uid/gid of the sysfs directories
+ * for the devices belonging to the class. Usually tied to
+ * device's namespace.
* @pm: The default device power management operations of this class.
* @p: The private data of the driver core, no one other than the
* driver core can touch this.
@@ -404,6 +407,8 @@ struct class {
const struct kobj_ns_type_operations *ns_type;
const void *(*namespace)(struct device *dev);

+ void (*get_ownership)(struct device *dev, kuid_t *uid, kgid_t *gid);
+
const struct dev_pm_ops *pm;

struct subsys_private *p;
--
2.8.0.rc3.226.g39d4020