libev/ev.c

/*
 * libev event processing core, watcher management
 *
 * 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.
 */

#ifdef __cplusplus
extern "C" {
#endif

#ifndef EV_STANDALONE
# ifdef EV_CONFIG_H
#  include EV_CONFIG_H
# else
#  include "config.h"
# endif

# if HAVE_CLOCK_GETTIME
#  ifndef EV_USE_MONOTONIC
#   define EV_USE_MONOTONIC 1
#  endif
#  ifndef EV_USE_REALTIME
#   define EV_USE_REALTIME  1
#  endif
# else
#  ifndef EV_USE_MONOTONIC
#   define EV_USE_MONOTONIC 0
#  endif
#  ifndef EV_USE_REALTIME
#   define EV_USE_REALTIME  0
#  endif
# endif

# ifndef EV_USE_SELECT
#  if HAVE_SELECT && HAVE_SYS_SELECT_H
#   define EV_USE_SELECT 1
#  else
#   define EV_USE_SELECT 0
#  endif
# endif

# ifndef EV_USE_POLL
#  if HAVE_POLL && HAVE_POLL_H
#   define EV_USE_POLL 1
#  else
#   define EV_USE_POLL 0
#  endif
# endif
   
# ifndef EV_USE_EPOLL
#  if HAVE_EPOLL_CTL && HAVE_SYS_EPOLL_H
#   define EV_USE_EPOLL 1
#  else
#   define EV_USE_EPOLL 0
#  endif
# endif
   
# ifndef EV_USE_KQUEUE
#  if HAVE_KQUEUE && HAVE_SYS_EVENT_H && HAVE_SYS_QUEUE_H
#   define EV_USE_KQUEUE 1
#  else
#   define EV_USE_KQUEUE 0
#  endif
# endif
   
# ifndef EV_USE_PORT
#  if HAVE_PORT_H && HAVE_PORT_CREATE
#   define EV_USE_PORT 1
#  else
#   define EV_USE_PORT 0
#  endif
# endif

# ifndef EV_USE_INOTIFY
#  if HAVE_INOTIFY_INIT && HAVE_SYS_INOTIFY_H
#   define EV_USE_INOTIFY 1
#  else
#   define EV_USE_INOTIFY 0
#  endif
# endif

#endif

#include <math.h>
#include <stdlib.h>
#include <fcntl.h>
#include <stddef.h>

#include <stdio.h>

#include <assert.h>
#include <errno.h>
#include <sys/types.h>
#include <time.h>

#include <signal.h>

#ifdef EV_H
# include EV_H
#else
# include "ev.h"
#endif

#ifndef _WIN32
# include <sys/time.h>
# include <sys/wait.h>
# include <unistd.h>
#else
# define WIN32_LEAN_AND_MEAN
# include <windows.h>
# ifndef EV_SELECT_IS_WINSOCKET
#  define EV_SELECT_IS_WINSOCKET 1
# endif
#endif

/**/

#ifndef EV_USE_MONOTONIC
# define EV_USE_MONOTONIC 0
#endif

#ifndef EV_USE_REALTIME
# define EV_USE_REALTIME 0
#endif

#ifndef EV_USE_SELECT
# define EV_USE_SELECT 1
#endif

#ifndef EV_USE_POLL
# ifdef _WIN32
#  define EV_USE_POLL 0
# else
#  define EV_USE_POLL 1
# endif
#endif

#ifndef EV_USE_EPOLL
# define EV_USE_EPOLL 0
#endif

#ifndef EV_USE_KQUEUE
# define EV_USE_KQUEUE 0
#endif

#ifndef EV_USE_PORT
# define EV_USE_PORT 0
#endif

#ifndef EV_USE_INOTIFY
# define EV_USE_INOTIFY 0
#endif

#ifndef EV_PID_HASHSIZE
# if EV_MINIMAL
#  define EV_PID_HASHSIZE 1
# else
#  define EV_PID_HASHSIZE 16
# endif
#endif

#ifndef EV_INOTIFY_HASHSIZE
# if EV_MINIMAL
#  define EV_INOTIFY_HASHSIZE 1
# else
#  define EV_INOTIFY_HASHSIZE 16
# endif
#endif

/**/

#ifndef CLOCK_MONOTONIC
# undef EV_USE_MONOTONIC
# define EV_USE_MONOTONIC 0
#endif

#ifndef CLOCK_REALTIME
# undef EV_USE_REALTIME
# define EV_USE_REALTIME 0
#endif

#if !EV_STAT_ENABLE
# undef EV_USE_INOTIFY
# define EV_USE_INOTIFY 0
#endif

#if EV_USE_INOTIFY
# include <sys/inotify.h>
#endif

#if EV_SELECT_IS_WINSOCKET
# include <winsock.h>
#endif

/**/

/*
 * This is used to avoid floating point rounding problems.
 * It is added to ev_rt_now when scheduling periodics
 * to ensure progress, time-wise, even when rounding
 * errors are against us.
 * This value is good at least till the year 4000.
 * Better solutions welcome.
 */
#define TIME_EPSILON  0.0001220703125 /* 1/8192 */

#define MIN_TIMEJUMP  1. /* minimum timejump that gets detected (if monotonic clock available) */
#define MAX_BLOCKTIME 59.743 /* never wait longer than this time (to detect time jumps) */
/*#define CLEANUP_INTERVAL (MAX_BLOCKTIME * 5.) /* how often to try to free memory and re-check fds, TODO */

#if __GNUC__ >= 4
# define expect(expr,value)         __builtin_expect ((expr),(value))
# define noinline                   __attribute__ ((noinline))
#else
# define expect(expr,value)         (expr)
# define noinline
# if __STDC_VERSION__ < 199901L
#  define inline
# endif
#endif

#define expect_false(expr) expect ((expr) != 0, 0)
#define expect_true(expr)  expect ((expr) != 0, 1)
#define inline_size        static inline

#if EV_MINIMAL
# define inline_speed      static noinline
#else
# define inline_speed      static inline
#endif

#define NUMPRI    (EV_MAXPRI - EV_MINPRI + 1)
#define ABSPRI(w) (((W)w)->priority - EV_MINPRI)

#define EMPTY       /* required for microsofts broken pseudo-c compiler */
#define EMPTY2(a,b) /* used to suppress some warnings */

typedef ev_watcher *W;
typedef ev_watcher_list *WL;
typedef ev_watcher_time *WT;

static int have_monotonic; /* did clock_gettime (CLOCK_MONOTONIC) work? */

#ifdef _WIN32
# include "ev_win32.c"
#endif

/*****************************************************************************/

static void (*syserr_cb)(const char *msg);

void
ev_set_syserr_cb (void (*cb)(const char *msg))
{
  syserr_cb = cb;
}

static void noinline
syserr (const char *msg)
{
  if (!msg)
    msg = "(libev) system error";

  if (syserr_cb)
    syserr_cb (msg);
  else
    {
      perror (msg);
      abort ();
    }
}

static void *(*alloc)(void *ptr, long size);

void
ev_set_allocator (void *(*cb)(void *ptr, long size))
{
  alloc = cb;
}

inline_speed void *
ev_realloc (void *ptr, long size)
{
  ptr = alloc ? alloc (ptr, size) : realloc (ptr, size);

  if (!ptr && size)
    {
      fprintf (stderr, "libev: cannot allocate %ld bytes, aborting.", size);
      abort ();
    }

  return ptr;
}

#define ev_malloc(size) ev_realloc (0, (size))
#define ev_free(ptr)    ev_realloc ((ptr), 0)

/*****************************************************************************/

typedef struct
{
  WL head;
  unsigned char events;
  unsigned char reify;
#if EV_SELECT_IS_WINSOCKET
  SOCKET handle;
#endif
} ANFD;

typedef struct
{
  W w;
  int events;
} ANPENDING;

#if EV_USE_INOTIFY
typedef struct
{
  WL head;
} ANFS;
#endif

#if EV_MULTIPLICITY

  struct ev_loop
  {
    ev_tstamp ev_rt_now;
    #define ev_rt_now ((loop)->ev_rt_now)
    #define VAR(name,decl) decl;
      #include "ev_vars.h"
    #undef VAR
  };
  #include "ev_wrap.h"

  static struct ev_loop default_loop_struct;
  struct ev_loop *ev_default_loop_ptr;

#else

  ev_tstamp ev_rt_now;
  #define VAR(name,decl) static decl;
    #include "ev_vars.h"
  #undef VAR

  static int ev_default_loop_ptr;

#endif

/*****************************************************************************/

ev_tstamp
ev_time (void)
{
#if EV_USE_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
}

ev_tstamp inline_size
get_clock (void)
{
#if EV_USE_MONOTONIC
  if (expect_true (have_monotonic))
    {
      struct timespec ts;
      clock_gettime (CLOCK_MONOTONIC, &ts);
      return ts.tv_sec + ts.tv_nsec * 1e-9;
    }
#endif

  return ev_time ();
}

#if EV_MULTIPLICITY
ev_tstamp
ev_now (EV_P)
{
  return ev_rt_now;
}
#endif

int inline_size
array_nextsize (int elem, int cur, int cnt)
{
  int ncur = cur + 1;

  do
    ncur <<= 1;
  while (cnt > ncur);

  /* if size > 4096, round to 4096 - 4 * longs to accomodate malloc overhead */
  if (elem * ncur > 4096)
    {
      ncur *= elem;
      ncur = (ncur + elem + 4095 + sizeof (void *) * 4) & ~4095;
      ncur = ncur - sizeof (void *) * 4;
      ncur /= elem;
    }

  return ncur;
}

static noinline void *
array_realloc (int elem, void *base, int *cur, int cnt)
{
  *cur = array_nextsize (elem, *cur, cnt);
  return ev_realloc (base, elem * *cur);
}

#define array_needsize(type,base,cur,cnt,init)			\
  if (expect_false ((cnt) > (cur)))				\
    {								\
      int ocur_ = (cur);					\
      (base) = (type *)array_realloc				\
         (sizeof (type), (base), &(cur), (cnt));		\
      init ((base) + (ocur_), (cur) - ocur_);			\
    }

#if 0
#define array_slim(type,stem)					\
  if (stem ## max < array_roundsize (stem ## cnt >> 2))		\
    {								\
      stem ## max = array_roundsize (stem ## cnt >> 1);		\
      base = (type *)ev_realloc (base, sizeof (type) * (stem ## max));\
      fprintf (stderr, "slimmed down " # stem " to %d\n", stem ## max);/*D*/\
    }
#endif

#define array_free(stem, idx) \
  ev_free (stem ## s idx); stem ## cnt idx = stem ## max idx = 0;

/*****************************************************************************/

void noinline
ev_feed_event (EV_P_ void *w, int revents)
{
  W w_ = (W)w;
  int pri = ABSPRI (w_);

  if (expect_false (w_->pending))
    pendings [pri][w_->pending - 1].events |= revents;
  else
    {
      w_->pending = ++pendingcnt [pri];
      array_needsize (ANPENDING, pendings [pri], pendingmax [pri], w_->pending, EMPTY2);
      pendings [pri][w_->pending - 1].w      = w_;
      pendings [pri][w_->pending - 1].events = revents;
    }
}

void inline_speed
queue_events (EV_P_ W *events, int eventcnt, int type)
{
  int i;

  for (i = 0; i < eventcnt; ++i)
    ev_feed_event (EV_A_ events [i], type);
}

/*****************************************************************************/

void inline_size
anfds_init (ANFD *base, int count)
{
  while (count--)
    {
      base->head   = 0;
      base->events = EV_NONE;
      base->reify  = 0;

      ++base;
    }
}

void inline_speed
fd_event (EV_P_ int fd, int revents)
{
  ANFD *anfd = anfds + fd;
  ev_io *w;

  for (w = (ev_io *)anfd->head; w; w = (ev_io *)((WL)w)->next)
    {
      int ev = w->events & revents;

      if (ev)
        ev_feed_event (EV_A_ (W)w, ev);
    }
}

void
ev_feed_fd_event (EV_P_ int fd, int revents)
{
  if (fd >= 0 && fd < anfdmax)
    fd_event (EV_A_ fd, revents);
}

void inline_size
fd_reify (EV_P)
{
  int i;

  for (i = 0; i < fdchangecnt; ++i)
    {
      int fd = fdchanges [i];
      ANFD *anfd = anfds + fd;
      ev_io *w;

      unsigned char events = 0;

      for (w = (ev_io *)anfd->head; w; w = (ev_io *)((WL)w)->next)
        events |= (unsigned char)w->events;

#if EV_SELECT_IS_WINSOCKET
      if (events)
        {
          unsigned long argp;
          anfd->handle = _get_osfhandle (fd);
          assert (("libev only supports socket fds in this configuration", ioctlsocket (anfd->handle, FIONREAD, &argp) == 0));
        }
#endif

      {
        unsigned char o_events = anfd->events;
        unsigned char o_reify  = anfd->reify;

        anfd->reify  = 0;
        anfd->events = events;

        if (o_events != events || o_reify & EV_IOFDSET)
          backend_modify (EV_A_ fd, o_events, events);
      }
    }

  fdchangecnt = 0;
}

void inline_size
fd_change (EV_P_ int fd, int flags)
{
  unsigned char reify = anfds [fd].reify;
  anfds [fd].reify |= flags;

  if (expect_true (!reify))
    {
      ++fdchangecnt;
      array_needsize (int, fdchanges, fdchangemax, fdchangecnt, EMPTY2);
      fdchanges [fdchangecnt - 1] = fd;
    }
}

void inline_speed
fd_kill (EV_P_ int fd)
{
  ev_io *w;

  while ((w = (ev_io *)anfds [fd].head))
    {
      ev_io_stop (EV_A_ w);
      ev_feed_event (EV_A_ (W)w, EV_ERROR | EV_READ | EV_WRITE);
    }
}

int inline_size
fd_valid (int fd)
{
#ifdef _WIN32
  return _get_osfhandle (fd) != -1;
#else
  return fcntl (fd, F_GETFD) != -1;
#endif
}

/* called on EBADF to verify fds */
static void noinline
fd_ebadf (EV_P)
{
  int fd;

  for (fd = 0; fd < anfdmax; ++fd)
    if (anfds [fd].events)
      if (!fd_valid (fd) == -1 && errno == EBADF)
        fd_kill (EV_A_ fd);
}

/* called on ENOMEM in select/poll to kill some fds and retry */
static void noinline
fd_enomem (EV_P)
{
  int fd;

  for (fd = anfdmax; fd--; )
    if (anfds [fd].events)
      {
        fd_kill (EV_A_ fd);
        return;
      }
}

/* usually called after fork if backend needs to re-arm all fds from scratch */
static void noinline
fd_rearm_all (EV_P)
{
  int fd;

  for (fd = 0; fd < anfdmax; ++fd)
    if (anfds [fd].events)
      {
        anfds [fd].events = 0;
        fd_change (EV_A_ fd, EV_IOFDSET | 1);
      }
}

/*****************************************************************************/

void inline_speed
upheap (WT *heap, int k)
{
  WT w = heap [k];

  while (k)
    {
      int p = (k - 1) >> 1;

      if (heap [p]->at <= w->at)
        break;

      heap [k] = heap [p];
      ((W)heap [k])->active = k + 1;
      k = p;
    }

  heap [k] = w;
  ((W)heap [k])->active = k + 1;
}

void inline_speed
downheap (WT *heap, int N, int k)
{
  WT w = heap [k];

  for (;;)
    {
      int c = (k << 1) + 1;

      if (c >= N)
        break;

      c += c + 1 < N && heap [c]->at > heap [c + 1]->at
           ? 1 : 0;

      if (w->at <= heap [c]->at)
        break;

      heap [k] = heap [c];
      ((W)heap [k])->active = k + 1;

      k = c;
    }

  heap [k] = w;
  ((W)heap [k])->active = k + 1;
}

void inline_size
adjustheap (WT *heap, int N, int k)
{
  upheap (heap, k);
  downheap (heap, N, k);
}

/*****************************************************************************/

typedef struct
{
  WL head;
  sig_atomic_t volatile gotsig;
} ANSIG;

static ANSIG *signals;
static int signalmax;

static int sigpipe [2];
static sig_atomic_t volatile gotsig;
static ev_io sigev;

void inline_size
signals_init (ANSIG *base, int count)