LXR linux/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
  21asmlinkage 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
  31SYS_NI(timer_create);
  32SYS_NI(timer_gettime);
  33SYS_NI(timer_getoverrun);
  34SYS_NI(timer_settime);
  35SYS_NI(timer_delete);
  36SYS_NI(clock_adjtime);
  37SYS_NI(getitimer);
  38SYS_NI(setitimer);
  39#ifdef __ARCH_WANT_SYS_ALARM
  40SYS_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
  49SYSCALL_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
  61SYSCALL_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
  77SYSCALL_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
  96SYSCALL_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
 119long clock_nanosleep_restart(struct restart_block *restart_block)
 120{
 121        return hrtimer_nanosleep_restart(restart_block);
 122}
 123#endif
 124