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