time_namespace.h

  1/* SPDX-License-Identifier: GPL-2.0 */
  2#ifndef _LINUX_TIMENS_H
  3#define _LINUX_TIMENS_H
  4
  5
  6#include <linux/sched.h>
  7#include <linux/nsproxy.h>
  8#include <linux/ns_common.h>
  9#include <linux/err.h>
 10#include <linux/time64.h>
 11
 12struct user_namespace;
 13extern struct user_namespace init_user_ns;
 14
 15struct seq_file;
 16struct vm_area_struct;
 17
 18struct timens_offsets {
 19	struct timespec64 monotonic;
 20	struct timespec64 boottime;
 21};
 22
 23struct time_namespace {
 24	struct user_namespace	*user_ns;
 25	struct ucounts		*ucounts;
 26	struct ns_common	ns;
 27	struct timens_offsets	offsets;
 28	struct page		*vvar_page;
 29	/* If set prevents changing offsets after any task joined namespace. */
 30	bool			frozen_offsets;
 31} __randomize_layout;
 32
 33extern struct time_namespace init_time_ns;
 34
 35#ifdef CONFIG_TIME_NS
 36static inline struct time_namespace *to_time_ns(struct ns_common *ns)
 37{
 38	return container_of(ns, struct time_namespace, ns);
 39}
 40void __init time_ns_init(void);
 41extern int vdso_join_timens(struct task_struct *task,
 42			    struct time_namespace *ns);
 43extern void timens_commit(struct task_struct *tsk, struct time_namespace *ns);
 44
 45static inline struct time_namespace *get_time_ns(struct time_namespace *ns)
 46{
 47	ns_ref_inc(ns);
 48	return ns;
 49}
 50
 51struct time_namespace *copy_time_ns(u64 flags,
 52				    struct user_namespace *user_ns,
 53				    struct time_namespace *old_ns);
 54void free_time_ns(struct time_namespace *ns);
 55void timens_on_fork(struct nsproxy *nsproxy, struct task_struct *tsk);
 56struct page *find_timens_vvar_page(struct vm_area_struct *vma);
 57
 58static inline void put_time_ns(struct time_namespace *ns)
 59{
 60	if (ns_ref_put(ns))
 61		free_time_ns(ns);
 62}
 63
 64void proc_timens_show_offsets(struct task_struct *p, struct seq_file *m);
 65
 66struct proc_timens_offset {
 67	int			clockid;
 68	struct timespec64	val;
 69};
 70
 71int proc_timens_set_offset(struct file *file, struct task_struct *p,
 72			   struct proc_timens_offset *offsets, int n);
 73
 74static inline void timens_add_monotonic(struct timespec64 *ts)
 75{
 76	struct timens_offsets *ns_offsets = &current->nsproxy->time_ns->offsets;
 77
 78	*ts = timespec64_add(*ts, ns_offsets->monotonic);
 79}
 80
 81static inline void timens_add_boottime(struct timespec64 *ts)
 82{
 83	struct timens_offsets *ns_offsets = &current->nsproxy->time_ns->offsets;
 84
 85	*ts = timespec64_add(*ts, ns_offsets->boottime);
 86}
 87
 88static inline u64 timens_add_boottime_ns(u64 nsec)
 89{
 90	struct timens_offsets *ns_offsets = &current->nsproxy->time_ns->offsets;
 91
 92	return nsec + timespec64_to_ns(&ns_offsets->boottime);
 93}
 94
 95static inline void timens_sub_boottime(struct timespec64 *ts)
 96{
 97	struct timens_offsets *ns_offsets = &current->nsproxy->time_ns->offsets;
 98
 99	*ts = timespec64_sub(*ts, ns_offsets->boottime);
100}
101
102ktime_t do_timens_ktime_to_host(clockid_t clockid, ktime_t tim,
103				struct timens_offsets *offsets);
104
105static inline ktime_t timens_ktime_to_host(clockid_t clockid, ktime_t tim)
106{
107	struct time_namespace *ns = current->nsproxy->time_ns;
108
109	if (likely(ns == &init_time_ns))
110		return tim;
111
112	return do_timens_ktime_to_host(clockid, tim, &ns->offsets);
113}
114
115#else
116static inline void __init time_ns_init(void)
117{
118}
119
120static inline int vdso_join_timens(struct task_struct *task,
121				   struct time_namespace *ns)
122{
123	return 0;
124}
125
126static inline void timens_commit(struct task_struct *tsk,
127				 struct time_namespace *ns)
128{
129}
130
131static inline struct time_namespace *get_time_ns(struct time_namespace *ns)
132{
133	return NULL;
134}
135
136static inline void put_time_ns(struct time_namespace *ns)
137{
138}
139
140static inline
141struct time_namespace *copy_time_ns(u64 flags,
142				    struct user_namespace *user_ns,
143				    struct time_namespace *old_ns)
144{
145	if (flags & CLONE_NEWTIME)
146		return ERR_PTR(-EINVAL);
147
148	return old_ns;
149}
150
151static inline void timens_on_fork(struct nsproxy *nsproxy,
152				 struct task_struct *tsk)
153{
154	return;
155}
156
157static inline struct page *find_timens_vvar_page(struct vm_area_struct *vma)
158{
159	return NULL;
160}
161
162static inline void timens_add_monotonic(struct timespec64 *ts) { }
163static inline void timens_add_boottime(struct timespec64 *ts) { }
164
165static inline u64 timens_add_boottime_ns(u64 nsec)
166{
167	return nsec;
168}
169
170static inline void timens_sub_boottime(struct timespec64 *ts) { }
171
172static inline ktime_t timens_ktime_to_host(clockid_t clockid, ktime_t tim)
173{
174	return tim;
175}
176#endif
177
178#endif /* _LINUX_TIMENS_H */