kernel/time/posix-stubs.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Dummy stubs used when CONFIG_POSIX_TIMERS=n
 *
 * Created by:  Nicolas Pitre, July 2016
 * Copyright:   (C) 2016 Linaro Limited
 */

#include <linux/linkage.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/errno.h>
#include <linux/syscalls.h>
#include <linux/ktime.h>
#include <linux/timekeeping.h>
#include <linux/posix-timers.h>
#include <linux/time_namespace.h>
#include <linux/compat.h>

/*
 * We preserve minimal support for CLOCK_REALTIME and CLOCK_MONOTONIC
 * as it is easy to remain compatible with little code. CLOCK_BOOTTIME
 * is also included for convenience as at least systemd uses it.
 */

SYSCALL_DEFINE2(clock_settime, const clockid_t, which_clock,
		const struct __kernel_timespec __user *, tp)
{
	struct timespec64 new_tp;

	if (which_clock != CLOCK_REALTIME)
		return -EINVAL;
	if (get_timespec64(&new_tp, tp))
		return -EFAULT;

	return do_sys_settimeofday64(&new_tp, NULL);
}

static int do_clock_gettime(clockid_t which_clock, struct timespec64 *tp)
{
	switch (which_clock) {
	case CLOCK_REALTIME:
		ktime_get_real_ts64(tp);
		break;
	case CLOCK_MONOTONIC:
		ktime_get_ts64(tp);
		timens_add_monotonic(tp);
		break;
	case CLOCK_BOOTTIME:
		ktime_get_boottime_ts64(tp);
		timens_add_boottime(tp);
		break;
	default:
		return -EINVAL;
	}

	return 0;
}

SYSCALL_DEFINE2(clock_gettime, const clockid_t, which_clock,
		struct __kernel_timespec __user *, tp)
{
	int ret;
	struct timespec64 kernel_tp;

	ret = do_clock_gettime(which_clock, &kernel_tp);
	if (ret)
		return ret;

	if (put_timespec64(&kernel_tp, tp))
		return -EFAULT;
	return 0;
}

SYSCALL_DEFINE2(clock_getres, const clockid_t, which_clock, struct __kernel_timespec __user *, tp)
{
	struct timespec64 rtn_tp = {
		.tv_sec = 0,
		.tv_nsec = hrtimer_resolution,
	};

	switch (which_clock) {
	case CLOCK_REALTIME:
	case CLOCK_MONOTONIC:
	case CLOCK_BOOTTIME:
		if (put_timespec64(&rtn_tp, tp))
			return -EFAULT;
		return 0;
	default:
		return -EINVAL;
	}
}

SYSCALL_DEFINE4(clock_nanosleep, const clockid_t, which_clock, int, flags,
		const struct __kernel_timespec __user *, rqtp,
		struct __kernel_timespec __user *, rmtp)
{
	struct timespec64 t;
	ktime_t texp;

	switch (which_clock) {
	case CLOCK_REALTIME:
	case CLOCK_MONOTONIC:
	case CLOCK_BOOTTIME:
		break;
	default:
		return -EINVAL;
	}

	if (get_timespec64(&t, rqtp))
		return -EFAULT;
	if (!timespec64_valid(&t))
		return -EINVAL;
	if (flags & TIMER_ABSTIME)
		rmtp = NULL;
	current->restart_block.fn = do_no_restart_syscall;
	current->restart_block.nanosleep.type = rmtp ? TT_NATIVE : TT_NONE;
	current->restart_block.nanosleep.rmtp = rmtp;
	texp = timespec64_to_ktime(t);
	if (flags & TIMER_ABSTIME)
		texp = timens_ktime_to_host(which_clock, texp);
	return hrtimer_nanosleep(texp, flags & TIMER_ABSTIME ?
				 HRTIMER_MODE_ABS : HRTIMER_MODE_REL,
				 which_clock);
}

#ifdef CONFIG_COMPAT_32BIT_TIME

SYSCALL_DEFINE2(clock_settime32, const clockid_t, which_clock,
		struct old_timespec32 __user *, tp)
{
	struct timespec64 new_tp;

	if (which_clock != CLOCK_REALTIME)
		return -EINVAL;
	if (get_old_timespec32(&new_tp, tp))
		return -EFAULT;

	return do_sys_settimeofday64(&new_tp, NULL);
}

SYSCALL_DEFINE2(clock_gettime32, clockid_t, which_clock,
		struct old_timespec32 __user *, tp)
{
	int ret;
	struct timespec64 kernel_tp;

	ret = do_clock_gettime(which_clock, &kernel_tp);
	if (ret)
		return ret;

	if (put_old_timespec32(&kernel_tp, tp))
		return -EFAULT;
	return 0;
}

SYSCALL_DEFINE2(clock_getres_time32, clockid_t, which_clock,
		struct old_timespec32 __user *, tp)
{
	struct timespec64 rtn_tp = {
		.tv_sec = 0,
		.tv_nsec = hrtimer_resolution,
	};

	switch (which_clock) {
	case CLOCK_REALTIME:
	case CLOCK_MONOTONIC:
	case CLOCK_BOOTTIME:
		if (put_old_timespec32(&rtn_tp, tp))
			return -EFAULT;
		return 0;
	default:
		return -EINVAL;
	}
}

SYSCALL_DEFINE4(clock_nanosleep_time32, clockid_t, which_clock, int, flags,
		struct old_timespec32 __user *, rqtp,
		struct old_timespec32 __user *, rmtp)
{
	struct timespec64 t;
	ktime_t texp;

	switch (which_clock) {
	case CLOCK_REALTIME:
	case CLOCK_MONOTONIC:
	case CLOCK_BOOTTIME:
		break;
	default:
		return -EINVAL;
	}

	if (get_old_timespec32(&t, rqtp))
		return -EFAULT;
	if (!timespec64_valid(&t))
		return -EINVAL;
	if (flags & TIMER_ABSTIME)
		rmtp = NULL;
	current->restart_block.fn = do_no_restart_syscall;
	current->restart_block.nanosleep.type = rmtp ? TT_COMPAT : TT_NONE;
	current->restart_block.nanosleep.compat_rmtp = rmtp;
	texp = timespec64_to_ktime(t);
	if (flags & TIMER_ABSTIME)
		texp = timens_ktime_to_host(which_clock, texp);
	return hrtimer_nanosleep(texp, flags & TIMER_ABSTIME ?
				 HRTIMER_MODE_ABS : HRTIMER_MODE_REL,
				 which_clock);
}
#endif