xref: /linux-6.15/include/linux/time_namespace.h (revision 8d7253dc) 
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 
11 struct user_namespace;
12 extern struct user_namespace init_user_ns;
13 
14 struct timens_offsets {
15 	struct timespec64 monotonic;
16 	struct timespec64 boottime;
17 };
18 
19 struct time_namespace {
20 	struct user_namespace	*user_ns;
21 	struct ucounts		*ucounts;
22 	struct ns_common	ns;
23 	struct timens_offsets	offsets;
24 	struct page		*vvar_page;
25 	/* If set prevents changing offsets after any task joined namespace. */
26 	bool			frozen_offsets;
27 } __randomize_layout;
28 
29 extern struct time_namespace init_time_ns;
30 
31 #ifdef CONFIG_TIME_NS
32 extern int vdso_join_timens(struct task_struct *task,
33 			    struct time_namespace *ns);
34 extern void timens_commit(struct task_struct *tsk, struct time_namespace *ns);
35 
36 static inline struct time_namespace *get_time_ns(struct time_namespace *ns)
37 {
38 	refcount_inc(&ns->ns.count);
39 	return ns;
40 }
41 
42 struct time_namespace *copy_time_ns(unsigned long flags,
43 				    struct user_namespace *user_ns,
44 				    struct time_namespace *old_ns);
45 void free_time_ns(struct time_namespace *ns);
46 void timens_on_fork(struct nsproxy *nsproxy, struct task_struct *tsk);
47 struct vdso_data *arch_get_vdso_data(void *vvar_page);
48 struct page *find_timens_vvar_page(struct vm_area_struct *vma);
49 
50 static inline void put_time_ns(struct time_namespace *ns)
51 {
52 	if (refcount_dec_and_test(&ns->ns.count))
53 		free_time_ns(ns);
54 }
55 
56 void proc_timens_show_offsets(struct task_struct *p, struct seq_file *m);
57 
58 struct proc_timens_offset {
59 	int			clockid;
60 	struct timespec64	val;
61 };
62 
63 int proc_timens_set_offset(struct file *file, struct task_struct *p,
64 			   struct proc_timens_offset *offsets, int n);
65 
66 static inline void timens_add_monotonic(struct timespec64 *ts)
67 {
68 	struct timens_offsets *ns_offsets = &current->nsproxy->time_ns->offsets;
69 
70 	*ts = timespec64_add(*ts, ns_offsets->monotonic);
71 }
72 
73 static inline void timens_add_boottime(struct timespec64 *ts)
74 {
75 	struct timens_offsets *ns_offsets = &current->nsproxy->time_ns->offsets;
76 
77 	*ts = timespec64_add(*ts, ns_offsets->boottime);
78 }
79 
80 static inline u64 timens_add_boottime_ns(u64 nsec)
81 {
82 	struct timens_offsets *ns_offsets = &current->nsproxy->time_ns->offsets;
83 
84 	return nsec + timespec64_to_ns(&ns_offsets->boottime);
85 }
86 
87 static inline void timens_sub_boottime(struct timespec64 *ts)
88 {
89 	struct timens_offsets *ns_offsets = &current->nsproxy->time_ns->offsets;
90 
91 	*ts = timespec64_sub(*ts, ns_offsets->boottime);
92 }
93 
94 ktime_t do_timens_ktime_to_host(clockid_t clockid, ktime_t tim,
95 				struct timens_offsets *offsets);
96 
97 static inline ktime_t timens_ktime_to_host(clockid_t clockid, ktime_t tim)
98 {
99 	struct time_namespace *ns = current->nsproxy->time_ns;
100 
101 	if (likely(ns == &init_time_ns))
102 		return tim;
103 
104 	return do_timens_ktime_to_host(clockid, tim, &ns->offsets);
105 }
106 
107 #else
108 static inline int vdso_join_timens(struct task_struct *task,
109 				   struct time_namespace *ns)
110 {
111 	return 0;
112 }
113 
114 static inline void timens_commit(struct task_struct *tsk,
115 				 struct time_namespace *ns)
116 {
117 }
118 
119 static inline struct time_namespace *get_time_ns(struct time_namespace *ns)
120 {
121 	return NULL;
122 }
123 
124 static inline void put_time_ns(struct time_namespace *ns)
125 {
126 }
127 
128 static inline
129 struct time_namespace *copy_time_ns(unsigned long flags,
130 				    struct user_namespace *user_ns,
131 				    struct time_namespace *old_ns)
132 {
133 	if (flags & CLONE_NEWTIME)
134 		return ERR_PTR(-EINVAL);
135 
136 	return old_ns;
137 }
138 
139 static inline void timens_on_fork(struct nsproxy *nsproxy,
140 				 struct task_struct *tsk)
141 {
142 	return;
143 }
144 
145 static inline struct page *find_timens_vvar_page(struct vm_area_struct *vma)
146 {
147 	return NULL;
148 }
149 
150 static inline void timens_add_monotonic(struct timespec64 *ts) { }
151 static inline void timens_add_boottime(struct timespec64 *ts) { }
152 
153 static inline u64 timens_add_boottime_ns(u64 nsec)
154 {
155 	return nsec;
156 }
157 
158 static inline void timens_sub_boottime(struct timespec64 *ts) { }
159 
160 static inline ktime_t timens_ktime_to_host(clockid_t clockid, ktime_t tim)
161 {
162 	return tim;
163 }
164 #endif
165 
166 #endif /* _LINUX_TIMENS_H */
167