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libev/ev.c

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/*
* Copyright (c) 2007 Marc Alexander Lehmann <libev@schmorp.de>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* * Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following
* disclaimer in the documentation and/or other materials provided
* with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <math.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <signal.h>
#include <stddef.h>
#include <stdio.h>
#include <assert.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <sys/time.h>
#include <time.h>
#ifndef HAVE_MONOTONIC
# ifdef CLOCK_MONOTONIC
# define HAVE_MONOTONIC 1
# endif
#endif
#ifndef HAVE_SELECT
# define HAVE_SELECT 1
#endif
#ifndef HAVE_EPOLL
# define HAVE_EPOLL 0
#endif
#ifndef HAVE_REALTIME
# define HAVE_REALTIME 1 /* posix requirement, but might be slower */
#endif
#define MIN_TIMEJUMP 1. /* minimum timejump that gets detected (if monotonic clock available) */
#define MAX_BLOCKTIME 60.
#define PID_HASHSIZE 16 /* size of pid hahs table, must be power of two */
#include "ev.h"
typedef struct ev_watcher *W;
typedef struct ev_watcher_list *WL;
typedef struct ev_watcher_time *WT;
static ev_tstamp now, diff; /* monotonic clock */
ev_tstamp ev_now;
int ev_method;
static int have_monotonic; /* runtime */
static ev_tstamp method_fudge; /* stupid epoll-returns-early bug */
static void (*method_modify)(int fd, int oev, int nev);
static void (*method_poll)(ev_tstamp timeout);
/*****************************************************************************/
ev_tstamp
ev_time (void)
{
#if HAVE_REALTIME
struct timespec ts;
clock_gettime (CLOCK_REALTIME, &ts);
return ts.tv_sec + ts.tv_nsec * 1e-9;
#else
struct timeval tv;
gettimeofday (&tv, 0);
return tv.tv_sec + tv.tv_usec * 1e-6;
#endif
}
static ev_tstamp
get_clock (void)
{
#if HAVE_MONOTONIC
if (have_monotonic)
{
struct timespec ts;
clock_gettime (CLOCK_MONOTONIC, &ts);
return ts.tv_sec + ts.tv_nsec * 1e-9;
}
#endif
return ev_time ();
}
#define array_needsize(base,cur,cnt,init) \
if ((cnt) > cur) \
{ \
int newcnt = cur; \
do \
{ \
newcnt = (newcnt << 1) | 4 & ~3; \
} \
while ((cnt) > newcnt); \
\
base = realloc (base, sizeof (*base) * (newcnt)); \
init (base + cur, newcnt - cur); \
cur = newcnt; \
}
/*****************************************************************************/
typedef struct
{
struct ev_io *head;
unsigned char wev, rev; /* want, received event set */
} ANFD;
static ANFD *anfds;
static int anfdmax;
static int *fdchanges;
static int fdchangemax, fdchangecnt;
static void
anfds_init (ANFD *base, int count)
{
while (count--)
{
base->head = 0;
base->wev = base->rev = EV_NONE;
++base;
}
}
typedef struct
{
W w;
int events;
} ANPENDING;
static ANPENDING *pendings;
static int pendingmax, pendingcnt;
static void
event (W w, int events)
{
if (w->active)
{
w->pending = ++pendingcnt;
array_needsize (pendings, pendingmax, pendingcnt, );
pendings [pendingcnt - 1].w = w;
pendings [pendingcnt - 1].events = events;
}
}
static void
fd_event (int fd, int events)
{
ANFD *anfd = anfds + fd;
struct ev_io *w;
for (w = anfd->head; w; w = w->next)
{
int ev = w->events & events;
if (ev)
event ((W)w, ev);
}
}
static void
queue_events (W *events, int eventcnt, int type)
{
int i;
for (i = 0; i < eventcnt; ++i)
event (events [i], type);
}
/* called on EBADF to verify fds */
static void
fd_recheck ()
{
int fd;
for (fd = 0; fd < anfdmax; ++fd)
if (anfds [fd].wev)
if (fcntl (fd, F_GETFD) == -1 && errno == EBADF)
while (anfds [fd].head)
evio_stop (anfds [fd].head);
}
/*****************************************************************************/
static struct ev_timer **timers;
static int timermax, timercnt;
static struct ev_periodic **periodics;
static int periodicmax, periodiccnt;
static void
upheap (WT *timers, int k)
{
WT w = timers [k];
while (k && timers [k >> 1]->at > w->at)
{
timers [k] = timers [k >> 1];
timers [k]->active = k + 1;
k >>= 1;
}
timers [k] = w;
timers [k]->active = k + 1;
}
static void
downheap (WT *timers, int N, int k)
{
WT w = timers [k];
while (k < (N >> 1))
{
int j = k << 1;
if (j + 1 < N && timers [j]->at > timers [j + 1]->at)
++j;
if (w->at <= timers [j]->at)
break;
timers [k] = timers [j];
timers [k]->active = k + 1;
k = j;
}
timers [k] = w;
timers [k]->active = k + 1;
}
/*****************************************************************************/
typedef struct
{
struct ev_signal *head;
sig_atomic_t gotsig;
} ANSIG;
static ANSIG *signals;
static int signalmax;
static int sigpipe [2];
static sig_atomic_t gotsig;
static struct ev_io sigev;
static void
signals_init (ANSIG *base, int count)
{
while (count--)
{
base->head = 0;
base->gotsig = 0;
++base;
}
}
static void
sighandler (int signum)
{
signals [signum - 1].gotsig = 1;
if (!gotsig)
{
gotsig = 1;
write (sigpipe [1], &gotsig, 1);
}
}
static void
sigcb (struct ev_io *iow, int revents)
{
struct ev_signal *w;
int sig;
gotsig = 0;
read (sigpipe [0], &revents, 1);
for (sig = signalmax; sig--; )
if (signals [sig].gotsig)
{
signals [sig].gotsig = 0;
for (w = signals [sig].head; w; w = w->next)
event ((W)w, EV_SIGNAL);
}
}
static void
siginit (void)
{
fcntl (sigpipe [0], F_SETFD, FD_CLOEXEC);
fcntl (sigpipe [1], F_SETFD, FD_CLOEXEC);
/* rather than sort out wether we really need nb, set it */
fcntl (sigpipe [0], F_SETFL, O_NONBLOCK);
fcntl (sigpipe [1], F_SETFL, O_NONBLOCK);
evio_set (&sigev, sigpipe [0], EV_READ);
evio_start (&sigev);
}
/*****************************************************************************/
static struct ev_idle **idles;
static int idlemax, idlecnt;
static struct ev_prepare **prepares;
static int preparemax, preparecnt;
static struct ev_check **checks;
static int checkmax, checkcnt;
/*****************************************************************************/
static struct ev_child *childs [PID_HASHSIZE];
static struct ev_signal childev;
#ifndef WCONTINUED
# define WCONTINUED 0
#endif
static void
childcb (struct ev_signal *sw, int revents)
{
struct ev_child *w;
int pid, status;
while ((pid = waitpid (-1, &status, WNOHANG | WUNTRACED | WCONTINUED)) != -1)
for (w = childs [pid & (PID_HASHSIZE - 1)]; w; w = w->next)
if (w->pid == pid || w->pid == -1)
{
w->status = status;
event ((W)w, EV_CHILD);
}
}
/*****************************************************************************/
#if HAVE_EPOLL
# include "ev_epoll.c"
#endif
#if HAVE_SELECT
# include "ev_select.c"
#endif
int ev_init (int flags)
{
if (!ev_method)
{
#if HAVE_MONOTONIC
{
struct timespec ts;
if (!clock_gettime (CLOCK_MONOTONIC, &ts))
have_monotonic = 1;
}
#endif
ev_now = ev_time ();
now = get_clock ();
diff = ev_now - now;
if (pipe (sigpipe))
return 0;
ev_method = EVMETHOD_NONE;
#if HAVE_EPOLL
if (ev_method == EVMETHOD_NONE) epoll_init (flags);
#endif
#if HAVE_SELECT
if (ev_method == EVMETHOD_NONE) select_init (flags);
#endif
if (ev_method)
{
evw_init (&sigev, sigcb);
siginit ();
evsignal_init (&childev, childcb, SIGCHLD);
evsignal_start (&childev);
}
}
return ev_method;
}
/*****************************************************************************/
void ev_prefork (void)
{
/* nop */
}
void ev_postfork_parent (void)
{
/* nop */
}
void ev_postfork_child (void)
{
#if HAVE_EPOLL
if (ev_method == EVMETHOD_EPOLL)
epoll_postfork_child ();
#endif
evio_stop (&sigev);
close (sigpipe [0]);
close (sigpipe [1]);
pipe (sigpipe);
siginit ();
}
/*****************************************************************************/
static void
fd_reify (void)
{
int i;
for (i = 0; i < fdchangecnt; ++i)
{
int fd = fdchanges [i];
ANFD *anfd = anfds + fd;
struct ev_io *w;
int wev = 0;
for (w = anfd->head; w; w = w->next)
wev |= w->events;
if (anfd->wev != wev)
{
method_modify (fd, anfd->wev, wev);
anfd->wev = wev;
}
}
fdchangecnt = 0;
}
static void
call_pending ()
{
while (pendingcnt)
{
ANPENDING *p = pendings + --pendingcnt;
if (p->w)
{
p->w->pending = 0;
p->w->cb (p->w, p->events);
}
}
}
static void
timers_reify ()
{
while (timercnt && timers [0]->at <= now)
{
struct ev_timer *w = timers [0];
event ((W)w, EV_TIMEOUT);
/* first reschedule or stop timer */
if (w->repeat)
{
w->at = now + w->repeat;
assert (("timer timeout in the past, negative repeat?", w->at > now));
downheap ((WT *)timers, timercnt, 0);
}
else
evtimer_stop (w); /* nonrepeating: stop timer */
}
}
static void
periodics_reify ()
{
while (periodiccnt && periodics [0]->at <= ev_now)
{
struct ev_periodic *w = periodics [0];
/* first reschedule or stop timer */
if (w->interval)
{
w->at += floor ((ev_now - w->at) / w->interval + 1.) * w->interval;
assert (("periodic timeout in the past, negative interval?", w->at > ev_now));
downheap ((WT *)periodics, periodiccnt, 0);
}
else
evperiodic_stop (w); /* nonrepeating: stop timer */
event ((W)w, EV_TIMEOUT);
}
}
static void
periodics_reschedule (ev_tstamp diff)
{
int i;
/* adjust periodics after time jump */
for (i = 0; i < periodiccnt; ++i)
{
struct ev_periodic *w = periodics [i];
if (w->interval)
{
ev_tstamp diff = ceil ((ev_now - w->at) / w->interval) * w->interval;
if (fabs (diff) >= 1e-4)
{
evperiodic_stop (w);
evperiodic_start (w);
i = 0; /* restart loop, inefficient, but time jumps should be rare */
}
}
}
}
static void
time_update ()
{
int i;
ev_now = ev_time ();
if (have_monotonic)
{
ev_tstamp odiff = diff;
for (i = 4; --i; ) /* loop a few times, before making important decisions */
{
now = get_clock ();
diff = ev_now - now;
if (fabs (odiff - diff) < MIN_TIMEJUMP)
return; /* all is well */
ev_now = ev_time ();
}
periodics_reschedule (diff - odiff);
/* no timer adjustment, as the monotonic clock doesn't jump */
}
else
{
if (now > ev_now || now < ev_now - MAX_BLOCKTIME - MIN_TIMEJUMP)
{
periodics_reschedule (ev_now - now);
/* adjust timers. this is easy, as the offset is the same for all */
for (i = 0; i < timercnt; ++i)
timers [i]->at += diff;
}
now = ev_now;
}
}
int ev_loop_done;
void ev_loop (int flags)
{
double block;
ev_loop_done = flags & EVLOOP_ONESHOT ? 1 : 0;
do
{
/* queue check watchers (and execute them) */
if (preparecnt)
{
queue_events ((W *)prepares, preparecnt, EV_PREPARE);
call_pending ();
}
/* update fd-related kernel structures */
fd_reify ();
/* calculate blocking time */
/* we only need this for !monotonic clockor timers, but as we basically
always have timers, we just calculate it always */
ev_now = ev_time ();
if (flags & EVLOOP_NONBLOCK || idlecnt)
block = 0.;
else
{
block = MAX_BLOCKTIME;
if (timercnt)
{
ev_tstamp to = timers [0]->at - (have_monotonic ? get_clock () : ev_now) + method_fudge;
if (block > to) block = to;
}
if (periodiccnt)
{
ev_tstamp to = periodics [0]->at - ev_now + method_fudge;
if (block > to) block = to;
}
if (block < 0.) block = 0.;
}
method_poll (block);
/* update ev_now, do magic */
time_update ();
/* queue pending timers and reschedule them */
timers_reify (); /* relative timers called last */
periodics_reify (); /* absolute timers called first */
/* queue idle watchers unless io or timers are pending */
if (!pendingcnt)
queue_events ((W *)idles, idlecnt, EV_IDLE);
/* queue check watchers, to be executed first */
if (checkcnt)
queue_events ((W *)checks, checkcnt, EV_CHECK);
call_pending ();
}
while (!ev_loop_done);
if (ev_loop_done != 2)
ev_loop_done = 0;
}
/*****************************************************************************/
static void
wlist_add (WL *head, WL elem)
{
elem->next = *head;
*head = elem;
}
static void
wlist_del (WL *head, WL elem)
{
while (*head)
{
if (*head == elem)
{
*head = elem->next;
return;
}
head = &(*head)->next;
}
}
static void
ev_clear (W w)
{
if (w->pending)
{
pendings [w->pending - 1].w = 0;
w->pending = 0;
}
}
static void
ev_start (W w, int active)
{
w->active = active;
}
static void
ev_stop (W w)
{
w->active = 0;
}
/*****************************************************************************/
void
evio_start (struct ev_io *w)
{
if (ev_is_active (w))
return;
int fd = w->fd;
ev_start ((W)w, 1);
array_needsize (anfds, anfdmax, fd + 1, anfds_init);
wlist_add ((WL *)&anfds[fd].head, (WL)w);
++fdchangecnt;
array_needsize (fdchanges, fdchangemax, fdchangecnt, );
fdchanges [fdchangecnt - 1] = fd;
}
void
evio_stop (struct ev_io *w)
{
ev_clear ((W)w);
if (!ev_is_active (w))
return;
wlist_del ((WL *)&anfds[w->fd].head, (WL)w);
ev_stop ((W)w);
++fdchangecnt;
array_needsize (fdchanges, fdchangemax, fdchangecnt, );
fdchanges [fdchangecnt - 1] = w->fd;
}
void
evtimer_start (struct ev_timer *w)
{
if (ev_is_active (w))
return;
w->at += now;
assert (("timer repeat value less than zero not allowed", w->repeat >= 0.));
ev_start ((W)w, ++timercnt);
array_needsize (timers, timermax, timercnt, );
timers [timercnt - 1] = w;
upheap ((WT *)timers, timercnt - 1);
}
void
evtimer_stop (struct ev_timer *w)
{
ev_clear ((W)w);
if (!ev_is_active (w))
return;
if (w->active < timercnt--)
{
timers [w->active - 1] = timers [timercnt];
downheap ((WT *)timers, timercnt, w->active - 1);
}
w->at = w->repeat;
ev_stop ((W)w);
}
void
evtimer_again (struct ev_timer *w)
{
if (ev_is_active (w))
{
if (w->repeat)
{
w->at = now + w->repeat;
downheap ((WT *)timers, timercnt, w->active - 1);
}
else
evtimer_stop (w);
}
else if (w->repeat)
evtimer_start (w);
}
void
evperiodic_start (struct ev_periodic *w)
{
if (ev_is_active (w))
return;
assert (("periodic interval value less than zero not allowed", w->interval >= 0.));
/* this formula differs from the one in periodic_reify because we do not always round up */
if (w->interval)
w->at += ceil ((ev_now - w->at) / w->interval) * w->interval;
ev_start ((W)w, ++periodiccnt);
array_needsize (periodics, periodicmax, periodiccnt, );
periodics [periodiccnt - 1] = w;
upheap ((WT *)periodics, periodiccnt - 1);
}
void
evperiodic_stop (struct ev_periodic *w)
{
ev_clear ((W)w);
if (!ev_is_active (w))
return;
if (w->active < periodiccnt--)
{
periodics [w->active - 1] = periodics [periodiccnt];
downheap ((WT *)periodics, periodiccnt, w->active - 1);
}
ev_stop ((W)w);
}
void
evsignal_start (struct ev_signal *w)
{
if (ev_is_active (w))
return;
ev_start ((W)w, 1);
array_needsize (signals, signalmax, w->signum, signals_init);
wlist_add ((WL *)&signals [w->signum - 1].head, (WL)w);
if (!w->next)
{
struct sigaction sa;
sa.sa_handler = sighandler;
sigfillset (&sa.sa_mask);
sa.sa_flags = 0;
sigaction (w->signum, &sa, 0);
}
}
void
evsignal_stop (struct ev_signal *w)
{
ev_clear ((W)w);
if (!ev_is_active (w))
return;
wlist_del ((WL *)&signals [w->signum - 1].head, (WL)w);
ev_stop ((W)w);
if (!signals [w->signum - 1].head)
signal (w->signum, SIG_DFL);
}
void evidle_start (struct ev_idle *w)
{
if (ev_is_active (w))
return;
ev_start ((W)w, ++idlecnt);
array_needsize (idles, idlemax, idlecnt, );
idles [idlecnt - 1] = w;
}
void evidle_stop (struct ev_idle *w)
{
ev_clear ((W)w);
if (ev_is_active (w))
return;
idles [w->active - 1] = idles [--idlecnt];
ev_stop ((W)w);
}
void evprepare_start (struct ev_prepare *w)
{
if (ev_is_active (w))
return;
ev_start ((W)w, ++preparecnt);
array_needsize (prepares, preparemax, preparecnt, );
prepares [preparecnt - 1] = w;
}
void evprepare_stop (struct ev_prepare *w)
{
ev_clear ((W)w);
if (ev_is_active (w))
return;
prepares [w->active - 1] = prepares [--preparecnt];
ev_stop ((W)w);
}
void evcheck_start (struct ev_check *w)
{
if (ev_is_active (w))
return;
ev_start ((W)w, ++checkcnt);
array_needsize (checks, checkmax, checkcnt, );
checks [checkcnt - 1] = w;
}
void evcheck_stop (struct ev_check *w)
{
ev_clear ((W)w);
if (ev_is_active (w))
return;
checks [w->active - 1] = checks [--checkcnt];
ev_stop ((W)w);
}
void evchild_start (struct ev_child *w)
{
if (ev_is_active (w))
return;
ev_start ((W)w, 1);
wlist_add ((WL *)&childs [w->pid & (PID_HASHSIZE - 1)], (WL)w);
}
void evchild_stop (struct ev_child *w)
{
ev_clear ((W)w);
if (ev_is_active (w))
return;
wlist_del ((WL *)&childs [w->pid & (PID_HASHSIZE - 1)], (WL)w);
ev_stop ((W)w);
}
/*****************************************************************************/
struct ev_once
{
struct ev_io io;
struct ev_timer to;
void (*cb)(int revents, void *arg);
void *arg;
};
static void
once_cb (struct ev_once *once, int revents)
{
void (*cb)(int revents, void *arg) = once->cb;
void *arg = once->arg;
evio_stop (&once->io);
evtimer_stop (&once->to);
free (once);
cb (revents, arg);
}
static void
once_cb_io (struct ev_io *w, int revents)
{
once_cb ((struct ev_once *)(((char *)w) - offsetof (struct ev_once, io)), revents);
}
static void
once_cb_to (struct ev_timer *w, int revents)
{
once_cb ((struct ev_once *)(((char *)w) - offsetof (struct ev_once, to)), revents);
}
void
ev_once (int fd, int events, ev_tstamp timeout, void (*cb)(int revents, void *arg), void *arg)
{
struct ev_once *once = malloc (sizeof (struct ev_once));
if (!once)
cb (EV_ERROR, arg);
else
{
once->cb = cb;
once->arg = arg;
evw_init (&once->io, once_cb_io);
if (fd >= 0)
{
evio_set (&once->io, fd, events);
evio_start (&once->io);
}
evw_init (&once->to, once_cb_to);
if (timeout >= 0.)
{
evtimer_set (&once->to, timeout, 0.);
evtimer_start (&once->to);
}
}
}
/*****************************************************************************/
#if 0
struct ev_io wio;
static void
sin_cb (struct ev_io *w, int revents)
{
fprintf (stderr, "sin %d, revents %d\n", w->fd, revents);
}
static void
ocb (struct ev_timer *w, int revents)
{
//fprintf (stderr, "timer %f,%f (%x) (%f) d%p\n", w->at, w->repeat, revents, w->at - ev_time (), w->data);
evtimer_stop (w);
evtimer_start (w);
}
static void
scb (struct ev_signal *w, int revents)
{
fprintf (stderr, "signal %x,%d\n", revents, w->signum);
evio_stop (&wio);
evio_start (&wio);
}
static void
gcb (struct ev_signal *w, int revents)
{
fprintf (stderr, "generic %x\n", revents);
}
int main (void)
{
ev_init (0);
evio_init (&wio, sin_cb, 0, EV_READ);
evio_start (&wio);
struct ev_timer t[10000];
#if 0
int i;
for (i = 0; i < 10000; ++i)
{
struct ev_timer *w = t + i;
evw_init (w, ocb, i);
evtimer_init_abs (w, ocb, drand48 (), 0.99775533);
evtimer_start (w);
if (drand48 () < 0.5)
evtimer_stop (w);
}
#endif
struct ev_timer t1;
evtimer_init (&t1, ocb, 5, 10);
evtimer_start (&t1);
struct ev_signal sig;
evsignal_init (&sig, scb, SIGQUIT);
evsignal_start (&sig);
struct ev_check cw;
evcheck_init (&cw, gcb);
evcheck_start (&cw);
struct ev_idle iw;
evidle_init (&iw, gcb);
evidle_start (&iw);
ev_loop (0);
return 0;
}
#endif
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