[PATCH net-next v3 2/9] sysfs: add sysfs_link_change_owner()
From: Christian Brauner <hidden>
Date: 2020-02-18 16:30:12
Also in:
linux-pm, lkml
Subsystem:
driver core, kobjects, debugfs and sysfs, filesystems (vfs and infrastructure), the rest · Maintainers:
Greg Kroah-Hartman, "Rafael J. Wysocki", Danilo Krummrich, Alexander Viro, Christian Brauner, Linus Torvalds
Add a helper to change the owner of a sysfs link. This function will be used to correctly account for kobject ownership changes, e.g. when moving network devices between network namespaces. Signed-off-by: Christian Brauner <redacted> --- /* v2 */ - Greg Kroah-Hartman [off-list ref]: - Add comment how ownership of sysfs object is changed. /* v3 */ - Greg Kroah-Hartman [off-list ref]: - Add explicit uid/gid parameters. --- fs/sysfs/file.c | 40 ++++++++++++++++++++++++++++++++++++++++ include/linux/sysfs.h | 10 ++++++++++ 2 files changed, 50 insertions(+)
diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c
index 32bb04b4d9d9..df5107d7b3fd 100644
--- a/fs/sysfs/file.c
+++ b/fs/sysfs/file.c@@ -570,6 +570,46 @@ static int internal_change_owner(struct kernfs_node *kn, struct kobject *kobj, return kernfs_setattr(kn, &newattrs); } +/** + * sysfs_link_change_owner - change owner of a link. + * @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 + */ +int sysfs_link_change_owner(struct kobject *kobj, struct kobject *targ, + const char *name, kuid_t kuid, kgid_t kgid) +{ + struct kernfs_node *parent, *kn = NULL; + int error; + + if (!kobj) + parent = sysfs_root_kn; + else + parent = kobj->sd; + + if (!targ->state_in_sysfs) + return -EINVAL; + + error = -ENOENT; + kn = kernfs_find_and_get_ns(parent, 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, targ, kuid, kgid); + +out: + kernfs_put(kn); + return error; +} + /** * sysfs_file_change_owner_by_name - change owner of a file. * @kobj: object.
diff --git a/include/linux/sysfs.h b/include/linux/sysfs.h
index c11d11c78713..899500950410 100644
--- a/include/linux/sysfs.h
+++ b/include/linux/sysfs.h@@ -313,6 +313,8 @@ static inline void sysfs_enable_ns(struct kernfs_node *kn) int sysfs_file_change_owner(struct kobject *kobj, kuid_t kuid, kgid_t kgid); int sysfs_file_change_owner_by_name(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); #else /* CONFIG_SYSFS */
@@ -539,6 +541,14 @@ static inline int sysfs_file_change_owner_by_name(struct kobject *kobj, return 0; } +static inline int sysfs_link_change_owner(struct kobject *kobj, + struct kobject *targ, + const char *name, 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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2.25.0