Commit 303a4276 authored by Christian Brauner's avatar Christian Brauner Committed by David S. Miller
Browse files

sysfs: add sysfs_group{s}_change_owner() 



Add helpers to change the owner of sysfs groups.
This function will be used to correctly account for kobject ownership
changes, e.g. when moving network devices between network namespaces.

Reviewed-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: default avatarChristian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 0666a3ae

fs/sysfs/group.c

+115 −0
Original line number Diff line number Diff line
@@ -13,6 +13,7 @@ 
#include <linux/dcache.h>

#include <linux/namei.h>

#include <linux/err.h>

#include <linux/fs.h>

#include "sysfs.h"
@@ -457,3 +458,117 @@ int __compat_only_sysfs_link_entry_to_kobj(struct kobject *kobj, 
	return PTR_ERR_OR_ZERO(link);

}

EXPORT_SYMBOL_GPL(__compat_only_sysfs_link_entry_to_kobj);



static int sysfs_group_attrs_change_owner(struct kernfs_node *grp_kn,

					  const struct attribute_group *grp,

					  struct iattr *newattrs)

{

	struct kernfs_node *kn;

	int error;



	if (grp->attrs) {

		struct attribute *const *attr;



		for (attr = grp->attrs; *attr; attr++) {

			kn = kernfs_find_and_get(grp_kn, (*attr)->name);

			if (!kn)

				return -ENOENT;



			error = kernfs_setattr(kn, newattrs);

			kernfs_put(kn);

			if (error)

				return error;

		}

	}



	if (grp->bin_attrs) {

		struct bin_attribute *const *bin_attr;



		for (bin_attr = grp->bin_attrs; *bin_attr; bin_attr++) {

			kn = kernfs_find_and_get(grp_kn, (*bin_attr)->attr.name);

			if (!kn)

				return -ENOENT;



			error = kernfs_setattr(kn, newattrs);

			kernfs_put(kn);

			if (error)

				return error;

		}

	}



	return 0;

}



/**

 * sysfs_group_change_owner - change owner of an attribute group.

 * @kobj:	The kobject containing the group.

 * @grp:	The attribute group.

 * @kuid:	new owner's kuid

 * @kgid:	new owner's kgid

 *

 * Returns 0 on success or error code on failure.

 */

int sysfs_group_change_owner(struct kobject *kobj,

			     const struct attribute_group *grp, kuid_t kuid,

			     kgid_t kgid)

{

	struct kernfs_node *grp_kn;

	int error;

	struct iattr newattrs = {

		.ia_valid = ATTR_UID | ATTR_GID,

		.ia_uid = kuid,

		.ia_gid = kgid,

	};



	if (!kobj->state_in_sysfs)

		return -EINVAL;



	if (grp->name) {

		grp_kn = kernfs_find_and_get(kobj->sd, grp->name);

	} else {

		kernfs_get(kobj->sd);

		grp_kn = kobj->sd;

	}

	if (!grp_kn)

		return -ENOENT;



	error = kernfs_setattr(grp_kn, &newattrs);

	if (!error)

		error = sysfs_group_attrs_change_owner(grp_kn, grp, &newattrs);



	kernfs_put(grp_kn);



	return error;

}

EXPORT_SYMBOL_GPL(sysfs_group_change_owner);



/**

 * sysfs_groups_change_owner - change owner of a set of attribute groups.

 * @kobj:	The kobject containing the groups.

 * @groups:	The attribute groups.

 * @kuid:	new owner's kuid

 * @kgid:	new owner's kgid

 *

 * Returns 0 on success or error code on failure.

 */

int sysfs_groups_change_owner(struct kobject *kobj,

			      const struct attribute_group **groups,

			      kuid_t kuid, kgid_t kgid)

{

	int error = 0, i;



	if (!kobj->state_in_sysfs)

		return -EINVAL;



	if (!groups)

		return 0;



	for (i = 0; groups[i]; i++) {

		error = sysfs_group_change_owner(kobj, groups[i], kuid, kgid);

		if (error)

			break;

	}



	return error;

}

EXPORT_SYMBOL_GPL(sysfs_groups_change_owner);

include/linux/sysfs.h

+20 −0
Original line number Diff line number Diff line
@@ -314,6 +314,12 @@ int sysfs_file_change_owner(struct kobject *kobj, const char *name, kuid_t kuid, 
			    kgid_t kgid);

int sysfs_link_change_owner(struct kobject *kobj, struct kobject *targ,

			    const char *name, kuid_t kuid, kgid_t kgid);

int sysfs_groups_change_owner(struct kobject *kobj,

			      const struct attribute_group **groups,

			      kuid_t kuid, kgid_t kgid);

int sysfs_group_change_owner(struct kobject *kobj,

			     const struct attribute_group *groups, kuid_t kuid,

			     kgid_t kgid);



#else /* CONFIG_SYSFS */
@@ -542,6 +548,20 @@ static inline int sysfs_link_change_owner(struct kobject *kobj, 
	return 0;

}



static inline int sysfs_groups_change_owner(struct kobject *kobj,

			  const struct attribute_group **groups,

			  kuid_t kuid, kgid_t kgid)

{

	return 0;

}



static inline int sysfs_group_change_owner(struct kobject *kobj,

			 const struct attribute_group **groups,

			 kuid_t kuid, kgid_t kgid)

{

	return 0;

}



#endif /* CONFIG_SYSFS */



static inline int __must_check sysfs_create_file(struct kobject *kobj,

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