sendmail/libsm/clock.c

/*
 * Copyright (c) 1998-2004 Sendmail, Inc. and its suppliers.
 *  All rights reserved.
 * Copyright (c) 1983, 1995-1997 Eric P. Allman.  All rights reserved.
 * Copyright (c) 1988, 1993
 *  The Regents of the University of California.  All rights reserved.
 *
 * By using this file, you agree to the terms and conditions set
 * forth in the LICENSE file which can be found at the top level of
 * the sendmail distribution.
 *
 */

#pragma ident   "%Z%%M% %I% %E% SMI"

#include <sm/gen.h>
SM_RCSID("@(#)$Id: clock.c,v 1.47 2005/06/14 23:07:20 ca Exp $")
#include <unistd.h>
#include <time.h>
#include <errno.h>
#if SM_CONF_SETITIMER
# include <sm/time.h>
#endif /* SM_CONF_SETITIMER */
#include <sm/heap.h>
#include <sm/debug.h>
#include <sm/bitops.h>
#include <sm/clock.h>
#include "local.h"
#if _FFR_SLEEP_USE_SELECT > 0
# include <sys/types.h>
#endif /* _FFR_SLEEP_USE_SELECT > 0 */
#if defined(_FFR_MAX_SLEEP_TIME) && _FFR_MAX_SLEEP_TIME > 2
# include <syslog.h>
#endif /* defined(_FFR_MAX_SLEEP_TIME) && _FFR_MAX_SLEEP_TIME > 2 */

#ifndef sigmask
# define sigmask(s) (1 << ((s) - 1))
#endif /* ! sigmask */


/*
**  SM_SETEVENTM -- set an event to happen at a specific time in milliseconds.
**
**  Events are stored in a sorted list for fast processing.
**  An event only applies to the process that set it.
**  Source is #ifdef'd to work with older OS's that don't have setitimer()
**  (that is, don't have a timer granularity less than 1 second).
**
**  Parameters:
**      intvl -- interval until next event occurs (milliseconds).
**      func -- function to call on event.
**      arg -- argument to func on event.
**
**  Returns:
**      On success returns the SM_EVENT entry created.
**      On failure returns NULL.
**
**  Side Effects:
**      none.
*/

static SM_EVENT *volatile SmEventQueue;     /* head of event queue */
static SM_EVENT *volatile SmFreeEventList;  /* list of free events */

SM_EVENT *
sm_seteventm(intvl, func, arg)
    int intvl;
    void (*func)__P((int));
    int arg;
{
    ENTER_CRITICAL();
    if (SmFreeEventList == NULL)
    {
        SmFreeEventList = (SM_EVENT *) sm_pmalloc_x(sizeof *SmFreeEventList);
        SmFreeEventList->ev_link = NULL;
    }
    LEAVE_CRITICAL();

    return sm_sigsafe_seteventm(intvl, func, arg);
}

/*
**  NOTE:   THIS CAN BE CALLED FROM A SIGNAL HANDLER.  DO NOT ADD
**      ANYTHING TO THIS ROUTINE UNLESS YOU KNOW WHAT YOU ARE
**      DOING.
*/

SM_EVENT *
sm_sigsafe_seteventm(intvl, func, arg)
    int intvl;
    void (*func)__P((int));
    int arg;
{
    register SM_EVENT **evp;
    register SM_EVENT *ev;
#if SM_CONF_SETITIMER
    auto struct timeval now, nowi, ival;
    auto struct itimerval itime;
#else /*  SM_CONF_SETITIMER */
    auto time_t now, nowi;
#endif /*  SM_CONF_SETITIMER */
    int wasblocked;

    /* negative times are not allowed */
    if (intvl <= 0)
        return NULL;

    wasblocked = sm_blocksignal(SIGALRM);
#if SM_CONF_SETITIMER
    ival.tv_sec = intvl / 1000;
    ival.tv_usec = (intvl - ival.tv_sec * 1000) * 10;
    (void) gettimeofday(&now, NULL);
    nowi = now;
    timeradd(&now, &ival, &nowi);
#else /*  SM_CONF_SETITIMER */
    now = time(NULL);
    nowi = now + (time_t)(intvl / 1000);
#endif /*  SM_CONF_SETITIMER */

    /* search event queue for correct position */
    for (evp = (SM_EVENT **) (&SmEventQueue);
         (ev = *evp) != NULL;
         evp = &ev->ev_link)
    {
#if SM_CONF_SETITIMER
        if (timercmp(&(ev->ev_time), &nowi, >=))
#else /* SM_CONF_SETITIMER */
        if (ev->ev_time >= nowi)
#endif /* SM_CONF_SETITIMER */
            break;
    }

    ENTER_CRITICAL();
    if (SmFreeEventList == NULL)
    {
        /*
        **  This shouldn't happen.  If called from sm_seteventm(),
        **  we have just malloced a SmFreeEventList entry.  If
        **  called from a signal handler, it should have been
        **  from an existing event which sm_tick() just added to
        **  SmFreeEventList.
        */

        LEAVE_CRITICAL();
        if (wasblocked == 0)
            (void) sm_releasesignal(SIGALRM);
        return NULL;
    }
    else
    {
        ev = SmFreeEventList;
        SmFreeEventList = ev->ev_link;
    }
    LEAVE_CRITICAL();

    /* insert new event */
    ev->ev_time = nowi;
    ev->ev_func = func;
    ev->ev_arg = arg;
    ev->ev_pid = getpid();
    ENTER_CRITICAL();
    ev->ev_link = *evp;
    *evp = ev;
    LEAVE_CRITICAL();

    (void) sm_signal(SIGALRM, sm_tick);
# if SM_CONF_SETITIMER
    timersub(&SmEventQueue->ev_time, &now, &itime.it_value);
    itime.it_interval.tv_sec = 0;
    itime.it_interval.tv_usec = 0;
    if (itime.it_value.tv_sec < 0)
        itime.it_value.tv_sec = 0;
    if (itime.it_value.tv_sec == 0 && itime.it_value.tv_usec == 0)
        itime.it_value.tv_usec = 1000;
    (void) setitimer(ITIMER_REAL, &itime, NULL);
# else /* SM_CONF_SETITIMER */
    intvl = SmEventQueue->ev_time - now;
    (void) alarm((unsigned) (intvl < 1 ? 1 : intvl));
# endif /* SM_CONF_SETITIMER */
    if (wasblocked == 0)
        (void) sm_releasesignal(SIGALRM);
    return ev;
}
/*
**  SM_CLREVENT -- remove an event from the event queue.
**
**  Parameters:
**      ev -- pointer to event to remove.
**
**  Returns:
**      none.
**
**  Side Effects:
**      arranges for event ev to not happen.
*/

void
sm_clrevent(ev)
    register SM_EVENT *ev;
{
    register SM_EVENT **evp;
    int wasblocked;
# if SM_CONF_SETITIMER
    struct itimerval clr;
# endif /* SM_CONF_SETITIMER */

    if (ev == NULL)
        return;

    /* find the parent event */
    wasblocked = sm_blocksignal(SIGALRM);
    for (evp = (SM_EVENT **) (&SmEventQueue);
         *evp != NULL;
         evp = &(*evp)->ev_link)
    {
        if (*evp == ev)
            break;
    }

    /* now remove it */
    if (*evp != NULL)
    {
        ENTER_CRITICAL();
        *evp = ev->ev_link;
        ev->ev_link = SmFreeEventList;
        SmFreeEventList = ev;
        LEAVE_CRITICAL();
    }

    /* restore clocks and pick up anything spare */
    if (wasblocked == 0)
        (void) sm_releasesignal(SIGALRM);
    if (SmEventQueue != NULL)
        (void) kill(getpid(), SIGALRM);
    else
    {
        /* nothing left in event queue, no need for an alarm */
# if SM_CONF_SETITIMER
        clr.it_interval.tv_sec = 0;
        clr.it_interval.tv_usec = 0;
        clr.it_value.tv_sec = 0;
        clr.it_value.tv_usec = 0;
        (void) setitimer(ITIMER_REAL, &clr, NULL);
# else /* SM_CONF_SETITIMER */
        (void) alarm(0);
# endif /* SM_CONF_SETITIMER */
    }
}
/*
**  SM_CLEAR_EVENTS -- remove all events from the event queue.
**
**  Parameters:
**      none.
**
**  Returns:
**      none.
*/

void
sm_clear_events()
{
    register SM_EVENT *ev;
#if SM_CONF_SETITIMER
    struct itimerval clr;
#endif /* SM_CONF_SETITIMER */
    int wasblocked;

    /* nothing will be left in event queue, no need for an alarm */
#if SM_CONF_SETITIMER
    clr.it_interval.tv_sec = 0;
    clr.it_interval.tv_usec = 0;
    clr.it_value.tv_sec = 0;
    clr.it_value.tv_usec = 0;
    (void) setitimer(ITIMER_REAL, &clr, NULL);
#else /* SM_CONF_SETITIMER */
    (void) alarm(0);
#endif /* SM_CONF_SETITIMER */

    if (SmEventQueue == NULL)
        return;

    wasblocked = sm_blocksignal(SIGALRM);

    /* find the end of the EventQueue */
    for (ev = SmEventQueue; ev->ev_link != NULL; ev = ev->ev_link)
        continue;

    ENTER_CRITICAL();
    ev->ev_link = SmFreeEventList;
    SmFreeEventList = SmEventQueue;
    SmEventQueue = NULL;
    LEAVE_CRITICAL();

    /* restore clocks and pick up anything spare */
    if (wasblocked == 0)
        (void) sm_releasesignal(SIGALRM);
}
/*
**  SM_TICK -- take a clock tick
**
**  Called by the alarm clock.  This routine runs events as needed.
**  Always called as a signal handler, so we assume that SIGALRM
**  has been blocked.
**
**  Parameters:
**      One that is ignored; for compatibility with signal handlers.
**
**  Returns:
**      none.
**
**  Side Effects:
**      calls the next function in EventQueue.
**
**  NOTE:   THIS CAN BE CALLED FROM A SIGNAL HANDLER.  DO NOT ADD
**      ANYTHING TO THIS ROUTINE UNLESS YOU KNOW WHAT YOU ARE
**      DOING.
*/

/* ARGSUSED */
SIGFUNC_DECL
sm_tick(sig)
    int sig;
{
    register SM_EVENT *ev;
    pid_t mypid;
    int save_errno = errno;
#if SM_CONF_SETITIMER
    struct itimerval clr;
    struct timeval now;
#else /* SM_CONF_SETITIMER */
    register time_t now;
#endif /* SM_CONF_SETITIMER */

#if SM_CONF_SETITIMER
    clr.it_interval.tv_sec = 0;
    clr.it_interval.tv_usec = 0;
    clr.it_value.tv_sec = 0;
    clr.it_value.tv_usec = 0;
    (void) setitimer(ITIMER_REAL, &clr, NULL);
    gettimeofday(&now, NULL);
#else /* SM_CONF_SETITIMER */
    (void) alarm(0);
    now = time(NULL);
#endif /* SM_CONF_SETITIMER */

    FIX_SYSV_SIGNAL(sig, sm_tick);
    errno = save_errno;
    CHECK_CRITICAL(sig);

    mypid = getpid();
    while (PendingSignal != 0)
    {
        int sigbit = 0;
        int sig = 0;

        if (bitset(PEND_SIGHUP, PendingSignal))
        {
            sigbit = PEND_SIGHUP;
            sig = SIGHUP;
        }
        else if (bitset(PEND_SIGINT, PendingSignal))
        {
            sigbit = PEND_SIGINT;
            sig = SIGINT;
        }
        else if (bitset(PEND_SIGTERM, PendingSignal))
        {
            sigbit = PEND_SIGTERM;
            sig = SIGTERM;
        }
        else if (bitset(PEND_SIGUSR1, PendingSignal))
        {
            sigbit = PEND_SIGUSR1;
            sig = SIGUSR1;
        }
        else
        {
            /* If we get here, we are in trouble */
            abort();
        }
        PendingSignal &= ~sigbit;
        kill(mypid, sig);
    }

#if SM_CONF_SETITIMER
    gettimeofday(&now, NULL);
#else /* SM_CONF_SETITIMER */
    now = time(NULL);
#endif /* SM_CONF_SETITIMER */
    while ((ev = SmEventQueue) != NULL &&
           (ev->ev_pid != mypid ||
#if SM_CONF_SETITIMER
        timercmp(&ev->ev_time, &now, <=)
#else /* SM_CONF_SETITIMER */
        ev->ev_time <= now
#endif /* SM_CONF_SETITIMER */
        ))
    {
        void (*f)__P((int));
        int arg;
        pid_t pid;

        /* process the event on the top of the queue */
        ev = SmEventQueue;
        SmEventQueue = SmEventQueue->ev_link;

        /* we must be careful in here because ev_func may not return */
        f = ev->ev_func;
        arg = ev->ev_arg;
        pid = ev->ev_pid;
        ENTER_CRITICAL();
        ev->ev_link = SmFreeEventList;
        SmFreeEventList = ev;
        LEAVE_CRITICAL();
        if (pid != getpid())
            continue;
        if (SmEventQueue != NULL)
        {
#if SM_CONF_SETITIMER
            if (timercmp(&SmEventQueue->ev_time, &now, >))
            {
                timersub(&SmEventQueue->ev_time, &now,
                     &clr.it_value);
                clr.it_interval.tv_sec = 0;
                clr.it_interval.tv_usec = 0;
                if (clr.it_value.tv_sec < 0)
                    clr.it_value.tv_sec = 0;
                if (clr.it_value.tv_sec == 0 &&
                    clr.it_value.tv_usec == 0)
                    clr.it_value.tv_usec = 1000;
                (void) setitimer(ITIMER_REAL, &clr, NULL);
            }
            else
            {
                clr.it_interval.tv_sec = 0;
                clr.it_interval.tv_usec = 0;
                clr.it_value.tv_sec = 3;
                clr.it_value.tv_usec = 0;
                (void) setitimer(ITIMER_REAL, &clr, NULL);
            }
#else /* SM_CONF_SETITIMER */
            if (SmEventQueue->ev_time > now)
                (void) alarm((unsigned) (SmEventQueue->ev_time
                             - now));
            else
                (void) alarm(3);
#endif /* SM_CONF_SETITIMER */
        }

        /* call ev_func */
        errno = save_errno;
        (*f)(arg);
#if SM_CONF_SETITIMER
        clr.it_interval.tv_sec = 0;
        clr.it_interval.tv_usec = 0;
        clr.it_value.tv_sec = 0;
        clr.it_value.tv_usec = 0;
        (void) setitimer(ITIMER_REAL, &clr, NULL);
        gettimeofday(&now, NULL);
#else /* SM_CONF_SETITIMER */
        (void) alarm(0);
        now = time(NULL);
#endif /* SM_CONF_SETITIMER */
    }
    if (SmEventQueue != NULL)
    {
#if SM_CONF_SETITIMER
        timersub(&SmEventQueue->ev_time, &now, &clr.it_value);
        clr.it_interval.tv_sec = 0;
        clr.it_interval.tv_usec = 0;
        if (clr.it_value.tv_sec < 0)
            clr.it_value.tv_sec = 0;
        if (clr.it_value.tv_sec == 0 && clr.it_value.tv_usec == 0)
            clr.it_value.tv_usec = 1000;
        (void) setitimer(ITIMER_REAL, &clr, NULL);
#else /* SM_CONF_SETITIMER */
        (void) alarm((unsigned) (SmEventQueue->ev_time - now));
#endif /* SM_CONF_SETITIMER */
    }
    errno = save_errno;
    return SIGFUNC_RETURN;
}
/*
**  SLEEP -- a version of sleep that works with this stuff
**
**  Because Unix sleep uses the alarm facility, I must reimplement
**  it here.
**
**  Parameters:
**      intvl -- time to sleep.
**
**  Returns:
**      zero.
**
**  Side Effects:
**      waits for intvl time.  However, other events can
**      be run during that interval.
*/


# if !HAVE_NANOSLEEP
static void sm_endsleep __P((int));
static bool volatile SmSleepDone;
# endif /* !HAVE_NANOSLEEP */

#ifndef SLEEP_T
# define SLEEP_T    unsigned int
#endif /* ! SLEEP_T */

SLEEP_T
sleep(intvl)
    unsigned int intvl;
{
#if HAVE_NANOSLEEP
    struct timespec rqtp;

    if (intvl == 0)
        return (SLEEP_T) 0;
    rqtp.tv_sec = intvl;
    rqtp.tv_nsec = 0;
    nanosleep(&rqtp, NULL);
    return (SLEEP_T) 0;
#else /* HAVE_NANOSLEEP */
    int was_held;
    SM_EVENT *ev;
#if _FFR_SLEEP_USE_SELECT > 0
    int r;
# if _FFR_SLEEP_USE_SELECT > 0
    struct timeval sm_io_to;
# endif /* _FFR_SLEEP_USE_SELECT > 0 */
#endif /* _FFR_SLEEP_USE_SELECT > 0 */
#if SM_CONF_SETITIMER
    struct timeval now, begin, diff;
# if _FFR_SLEEP_USE_SELECT > 0
    struct timeval slpv;
# endif /* _FFR_SLEEP_USE_SELECT > 0 */
#else /*  SM_CONF_SETITIMER */
    time_t begin, now;
#endif /*  SM_CONF_SETITIMER */

    if (intvl == 0)
        return (SLEEP_T) 0;
#if defined(_FFR_MAX_SLEEP_TIME) && _FFR_MAX_SLEEP_TIME > 2
    if (intvl > _FFR_MAX_SLEEP_TIME)
    {
        syslog(LOG_ERR, "sleep: interval=%u exceeds max value %d",
            intvl, _FFR_MAX_SLEEP_TIME);
# if 0
        SM_ASSERT(intvl < (unsigned int) INT_MAX);
# endif /* 0 */
        intvl = _FFR_MAX_SLEEP_TIME;
    }
#endif /* defined(_FFR_MAX_SLEEP_TIME) && _FFR_MAX_SLEEP_TIME > 2 */
    SmSleepDone = false;

#if SM_CONF_SETITIMER
# if _FFR_SLEEP_USE_SELECT > 0
    slpv.tv_sec = intvl;
    slpv.tv_usec = 0;
# endif /* _FFR_SLEEP_USE_SELECT > 0 */
    (void) gettimeofday(&now, NULL);
    begin = now;
#else /*  SM_CONF_SETITIMER */
    now = begin = time(NULL);
#endif /*  SM_CONF_SETITIMER */

    ev = sm_setevent((time_t) intvl, sm_endsleep, 0);
    if (ev == NULL)
    {
        /* COMPLAIN */
#if 0
        syslog(LOG_ERR, "sleep: sm_setevent(%u) failed", intvl);
#endif /* 0 */
        SmSleepDone = true;
    }
    was_held = sm_releasesignal(SIGALRM);

    while (!SmSleepDone)
    {
#if SM_CONF_SETITIMER
        (void) gettimeofday(&now, NULL);
        timersub(&now, &begin, &diff);
        if (diff.tv_sec < 0 ||
            (diff.tv_sec == 0 && diff.tv_usec == 0))
            break;
# if _FFR_SLEEP_USE_SELECT > 0
        timersub(&slpv, &diff, &sm_io_to);
# endif /* _FFR_SLEEP_USE_SELECT > 0 */
#else /* SM_CONF_SETITIMER */
        now = time(NULL);

        /*
        **  Check whether time expired before signal is released.
        **  Due to the granularity of time() add 1 to be on the
        **  safe side.
        */

        if (!(begin + (time_t) intvl + 1 > now))
            break;
# if _FFR_SLEEP_USE_SELECT > 0
        sm_io_to.tv_sec = intvl - (now - begin);
        if (sm_io_to.tv_sec <= 0)
            sm_io_to.tv_sec = 1;
        sm_io_to.tv_usec = 0;
# endif /* _FFR_SLEEP_USE_SELECT > 0 */
#endif /* SM_CONF_SETITIMER */
#if _FFR_SLEEP_USE_SELECT > 0
        if (intvl <= _FFR_SLEEP_USE_SELECT)
        {
            r = select(0, NULL, NULL, NULL, &sm_io_to);
            if (r == 0)
                break;
        }
        else
#endif /* _FFR_SLEEP_USE_SELECT > 0 */
        (void) pause();
    }

    /* if out of the loop without the event being triggered remove it */
    if (!SmSleepDone)
        sm_clrevent(ev);
    if (was_held > 0)
        (void) sm_blocksignal(SIGALRM);
    return (SLEEP_T) 0;
#endif /* HAVE_NANOSLEEP */
}

#if !HAVE_NANOSLEEP
static void
sm_endsleep(ignore)
    int ignore;
{
    /*
    **  NOTE: THIS CAN BE CALLED FROM A SIGNAL HANDLER.  DO NOT ADD
    **  ANYTHING TO THIS ROUTINE UNLESS YOU KNOW WHAT YOU ARE
    **  DOING.
    */

    SmSleepDone = true;
}
#endif /* !HAVE_NANOSLEEP */