fs/proc: Introduce /proc/pid/timens_offsets

API to set time namespace offsets for children processes, i.e.:
echo "$clockid $offset_sec $offset_nsec" > /proc/self/timens_offsets

Co-developed-by: Dmitry Safonov <dima@arista.com>
Signed-off-by: Andrei Vagin <avagin@gmail.com>
Signed-off-by: Dmitry Safonov <dima@arista.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20191112012724.250792-28-dima@arista.com

1 files changed, 10 insertions, 0 deletions

diff --git a/include/linux/time_namespace.h b/include/linux/time_namespace.h
index 04a2ba8b8a06..824d54e057eb 100644
--- a/include/linux/time_namespace.h
+++ b/include/linux/time_namespace.h
@@ -52,6 +52,16 @@ static inline void put_time_ns(struct time_namespace *ns)
 	kref_put(&ns->kref, free_time_ns);
 }
 
+void proc_timens_show_offsets(struct task_struct *p, struct seq_file *m);
+
+struct proc_timens_offset {
+	int			clockid;
+	struct timespec64	val;
+};
+
+int proc_timens_set_offset(struct file *file, struct task_struct *p,
+			   struct proc_timens_offset *offsets, int n);
+
 static inline void timens_add_monotonic(struct timespec64 *ts)
 {
 	struct timens_offsets *ns_offsets = &current->nsproxy->time_ns->offsets;