/* Copyright (C) 2014 Stony Brook University
   This file is part of Graphene Library OS.

   Graphene Library OS is free software: you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public License
   as published by the Free Software Foundation, either version 3 of the
   License, or (at your option) any later version.

   Graphene Library OS is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

/*
 * shim_sleep.c
 *
 * Implementation of system call "pause" and "nanosleep".
 */

#include <shim_internal.h>
#include <shim_utils.h>
#include <shim_table.h>
#include <shim_handle.h>
#include <shim_vma.h>
#include <shim_thread.h>

#include <pal.h>
#include <pal_error.h>

#include <errno.h>

static bool signal_pending (void)
{
    struct shim_thread* cur = get_cur_thread();
    if (!cur)
        return false;

    lock(&cur->lock);

    if (!cur->signal_logs || !cur->has_signal.counter) {
        unlock(&cur->lock);
        return false;
    }

    for (int sig = 1; sig <= NUM_SIGS; sig++) {
        if (atomic_read(&cur->signal_logs[sig - 1].head) !=
            atomic_read(&cur->signal_logs[sig - 1].tail)) {
            /* at least one signal of type sig... */
            if (!__sigismember(&cur->signal_mask, sig)) {
                /* ...and this type is not blocked  */
                unlock(&cur->lock);
                return true;
            }
        }
    }

    unlock(&cur->lock);
    return false;
}

int shim_do_pause (void)
{
    if (signal_pending())
        return -EINTR;

    /* ~0ULL micro sec ~= 805675 years */
    DkThreadDelayExecution(~((PAL_NUM)0));
    return -EINTR;
}

int shim_do_nanosleep (const struct __kernel_timespec * rqtp,
                       struct __kernel_timespec * rmtp)
{
    if (!rqtp)
        return -EFAULT;

    if (signal_pending()) {
        if (rmtp) {
            /* no time elapsed, so copy time interval from rqtp to rmtp */
            rmtp->tv_sec = rqtp->tv_sec;
            rmtp->tv_nsec = rqtp->tv_nsec;
        }
        return -EINTR;
    }

    unsigned long time = rqtp->tv_sec * 1000000L + rqtp->tv_nsec / 1000;
    unsigned long ret = DkThreadDelayExecution(time);

    if (ret < time) {
        if (rmtp) {
            unsigned long remtime = time - ret;
            rmtp->tv_sec = remtime / 1000000L;
            rmtp->tv_nsec = (remtime - rmtp->tv_sec * 1000) * 1000;
        }
        return -EINTR;
    }

    return 0;
}