kernel/time/posix-stubs.c

   1 /*
   2  * Dummy stubs used when CONFIG_POSIX_TIMERS=n
   3  *
   4  * Created by:  Nicolas Pitre, July 2016
   5  * Copyright:   (C) 2016 Linaro Limited
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  */
  11
  12 #include <linux/linkage.h>
  13 #include <linux/kernel.h>
  14 #include <linux/sched.h>
  15 #include <linux/errno.h>
  16 #include <linux/syscalls.h>
  17 #include <linux/ktime.h>
  18 #include <linux/timekeeping.h>
  19 #include <linux/posix-timers.h>
  20
  21 asmlinkage long sys_ni_posix_timers(void)
  22 {
  23         pr_err_once("process %d (%s) attempted a POSIX timer syscall "
  24                     "while CONFIG_POSIX_TIMERS is not set\n",
  25                     current->pid, current->comm);
  26         return -ENOSYS;
  27 }
  28
  29 #define SYS_NI(name)  SYSCALL_ALIAS(sys_##name, sys_ni_posix_timers)
  30
  31 SYS_NI(timer_create);
  32 SYS_NI(timer_gettime);
  33 SYS_NI(timer_getoverrun);
  34 SYS_NI(timer_settime);
  35 SYS_NI(timer_delete);
  36 SYS_NI(clock_adjtime);
  37 SYS_NI(getitimer);
  38 SYS_NI(setitimer);
  39 #ifdef __ARCH_WANT_SYS_ALARM
  40 SYS_NI(alarm);
  41 #endif
  42
  43 /*
  44  * We preserve minimal support for CLOCK_REALTIME and CLOCK_MONOTONIC
  45  * as it is easy to remain compatible with little code. CLOCK_BOOTTIME
  46  * is also included for convenience as at least systemd uses it.
  47  */
  48
  49 SYSCALL_DEFINE2(clock_settime, const clockid_t, which_clock,
  50                 const struct timespec __user *, tp)
  51 {
  52         struct timespec new_tp;
  53
  54         if (which_clock != CLOCK_REALTIME)
  55                 return -EINVAL;
  56         if (copy_from_user(&new_tp, tp, sizeof (*tp)))
  57                 return -EFAULT;
  58         return do_sys_settimeofday(&new_tp, NULL);
  59 }
  60
  61 SYSCALL_DEFINE2(clock_gettime, const clockid_t, which_clock,
  62                 struct timespec __user *,tp)
  63 {
  64         struct timespec kernel_tp;
  65
  66         switch (which_clock) {
  67         case CLOCK_REALTIME: ktime_get_real_ts(&kernel_tp); break;
  68         case CLOCK_MONOTONIC: ktime_get_ts(&kernel_tp); break;
  69         case CLOCK_BOOTTIME: get_monotonic_boottime(&kernel_tp); break;
  70         default: return -EINVAL;
  71         }
  72         if (copy_to_user(tp, &kernel_tp, sizeof (kernel_tp)))
  73                 return -EFAULT;
  74         return 0;
  75 }
  76
  77 SYSCALL_DEFINE2(clock_getres, const clockid_t, which_clock, struct timespec __user *, tp)
  78 {
  79         struct timespec rtn_tp = {
  80                 .tv_sec = 0,
  81                 .tv_nsec = hrtimer_resolution,
  82         };
  83
  84         switch (which_clock) {
  85         case CLOCK_REALTIME:
  86         case CLOCK_MONOTONIC:
  87         case CLOCK_BOOTTIME:
  88                 if (copy_to_user(tp, &rtn_tp, sizeof(rtn_tp)))
  89                         return -EFAULT;
  90                 return 0;
  91         default:
  92                 return -EINVAL;
  93         }
  94 }
  95
  96 SYSCALL_DEFINE4(clock_nanosleep, const clockid_t, which_clock, int, flags,
  97                 const struct timespec __user *, rqtp,
  98                 struct timespec __user *, rmtp)
  99 {
 100         struct timespec t;
 101
 102         switch (which_clock) {
 103         case CLOCK_REALTIME:
 104         case CLOCK_MONOTONIC:
 105         case CLOCK_BOOTTIME:
 106                 if (copy_from_user(&t, rqtp, sizeof (struct timespec)))
 107                         return -EFAULT;
 108                 if (!timespec_valid(&t))
 109                         return -EINVAL;
 110                 return hrtimer_nanosleep(&t, rmtp, flags & TIMER_ABSTIME ?
 111                                          HRTIMER_MODE_ABS : HRTIMER_MODE_REL,
 112                                          which_clock);
 113         default:
 114                 return -EINVAL;
 115         }
 116 }
 117
 118 #ifdef CONFIG_COMPAT
 119 long clock_nanosleep_restart(struct restart_block *restart_block)
 120 {
 121         return hrtimer_nanosleep_restart(restart_block);
 122 }
 123 #endif