linux-stable/include/linux/time_namespace.h
Christian Brauner 76c12881a3
nsproxy: support CLONE_NEWTIME with setns()
So far setns() was missing time namespace support. This was partially due
to it simply not being implemented but also because vdso_join_timens()
could still fail which made switching to multiple namespaces atomically
problematic. This is now fixed so support CLONE_NEWTIME with setns()

Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Reviewed-by: Andrei Vagin <avagin@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Serge Hallyn <serge@hallyn.com>
Cc: Dmitry Safonov <dima@arista.com>
Link: https://lore.kernel.org/r/20200706154912.3248030-4-christian.brauner@ubuntu.com
2020-07-08 11:14:22 +02:00

139 lines
3.3 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_TIMENS_H
#define _LINUX_TIMENS_H
#include <linux/sched.h>
#include <linux/kref.h>
#include <linux/nsproxy.h>
#include <linux/ns_common.h>
#include <linux/err.h>
struct user_namespace;
extern struct user_namespace init_user_ns;
struct timens_offsets {
struct timespec64 monotonic;
struct timespec64 boottime;
};
struct time_namespace {
struct kref kref;
struct user_namespace *user_ns;
struct ucounts *ucounts;
struct ns_common ns;
struct timens_offsets offsets;
struct page *vvar_page;
/* If set prevents changing offsets after any task joined namespace. */
bool frozen_offsets;
} __randomize_layout;
extern struct time_namespace init_time_ns;
#ifdef CONFIG_TIME_NS
extern int vdso_join_timens(struct task_struct *task,
struct time_namespace *ns);
extern void timens_commit(struct task_struct *tsk, struct time_namespace *ns);
static inline struct time_namespace *get_time_ns(struct time_namespace *ns)
{
kref_get(&ns->kref);
return ns;
}
struct time_namespace *copy_time_ns(unsigned long flags,
struct user_namespace *user_ns,
struct time_namespace *old_ns);
void free_time_ns(struct kref *kref);
int timens_on_fork(struct nsproxy *nsproxy, struct task_struct *tsk);
struct vdso_data *arch_get_vdso_data(void *vvar_page);
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;
*ts = timespec64_add(*ts, ns_offsets->monotonic);
}
static inline void timens_add_boottime(struct timespec64 *ts)
{
struct timens_offsets *ns_offsets = &current->nsproxy->time_ns->offsets;
*ts = timespec64_add(*ts, ns_offsets->boottime);
}
ktime_t do_timens_ktime_to_host(clockid_t clockid, ktime_t tim,
struct timens_offsets *offsets);
static inline ktime_t timens_ktime_to_host(clockid_t clockid, ktime_t tim)
{
struct time_namespace *ns = current->nsproxy->time_ns;
if (likely(ns == &init_time_ns))
return tim;
return do_timens_ktime_to_host(clockid, tim, &ns->offsets);
}
#else
static inline int vdso_join_timens(struct task_struct *task,
struct time_namespace *ns)
{
return 0;
}
static inline void timens_commit(struct task_struct *tsk,
struct time_namespace *ns)
{
}
static inline struct time_namespace *get_time_ns(struct time_namespace *ns)
{
return NULL;
}
static inline void put_time_ns(struct time_namespace *ns)
{
}
static inline
struct time_namespace *copy_time_ns(unsigned long flags,
struct user_namespace *user_ns,
struct time_namespace *old_ns)
{
if (flags & CLONE_NEWTIME)
return ERR_PTR(-EINVAL);
return old_ns;
}
static inline int timens_on_fork(struct nsproxy *nsproxy,
struct task_struct *tsk)
{
return 0;
}
static inline void timens_add_monotonic(struct timespec64 *ts) { }
static inline void timens_add_boottime(struct timespec64 *ts) { }
static inline ktime_t timens_ktime_to_host(clockid_t clockid, ktime_t tim)
{
return tim;
}
#endif
#endif /* _LINUX_TIMENS_H */