libev/ev.c

/*
 * libev event processing core, watcher management
 *
 * Copyright (c) 2007,2008,2009 Marc Alexander Lehmann <libev@schmorp.de>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modifica-
 * tion, are permitted provided that the following conditions are met:
 * 
 *   1.  Redistributions of source code must retain the above copyright notice,
 *       this list of conditions and the following disclaimer.
 * 
 *   2.  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 AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MER-
 * CHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO
 * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPE-
 * CIAL, 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 OTH-
 * ERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * Alternatively, the contents of this file may be used under the terms of
 * the GNU General Public License ("GPL") version 2 or any later version,
 * in which case the provisions of the GPL are applicable instead of
 * the above. If you wish to allow the use of your version of this file
 * only under the terms of the GPL and not to allow others to use your
 * version of this file under the BSD license, indicate your decision
 * by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL. If you do not delete the
 * provisions above, a recipient may use your version of this file under
 * either the BSD or the GPL.
 */

#ifdef __cplusplus
extern "C" {
#endif

/* this big block deduces configuration from config.h */
#ifndef EV_STANDALONE
# ifdef EV_CONFIG_H
#  include EV_CONFIG_H
# else
#  include "config.h"
# endif

# if HAVE_CLOCK_SYSCALL
#  ifndef EV_USE_CLOCK_SYSCALL
#   define EV_USE_CLOCK_SYSCALL 1
#   ifndef EV_USE_REALTIME
#    define EV_USE_REALTIME  0
#   endif
#   ifndef EV_USE_MONOTONIC
#    define EV_USE_MONOTONIC 1
#   endif
#  endif
# elif !defined(EV_USE_CLOCK_SYSCALL)
#  define EV_USE_CLOCK_SYSCALL 0
# endif

# if HAVE_CLOCK_GETTIME
#  ifndef EV_USE_MONOTONIC
#   define EV_USE_MONOTONIC 1
#  endif
#  ifndef EV_USE_REALTIME
#   define EV_USE_REALTIME  0
#  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_NANOSLEEP
#  if HAVE_NANOSLEEP
#   define EV_USE_NANOSLEEP 1
#  else
#   define EV_USE_NANOSLEEP 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

# ifndef EV_USE_SIGNALFD
#  if HAVE_SIGNALFD && HAVE_SYS_SIGNALFD_H
#   define EV_USE_SIGNALFD 1
#  else
#   define EV_USE_SIGNALFD 0
#  endif
# endif

# ifndef EV_USE_EVENTFD
#  if HAVE_EVENTFD
#   define EV_USE_EVENTFD 1
#  else
#   define EV_USE_EVENTFD 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
# include <io.h>
# define WIN32_LEAN_AND_MEAN
# include <windows.h>
# ifndef EV_SELECT_IS_WINSOCKET
#  define EV_SELECT_IS_WINSOCKET 1
# endif
#endif

/* this block tries to deduce configuration from header-defined symbols and defaults */

/* try to deduce the maximum number of signals on this platform */
#if defined (EV_NSIG)
/* use what's provided */
#elif defined (NSIG)
# define EV_NSIG (NSIG)
#elif defined(_NSIG)
# define EV_NSIG (_NSIG)
#elif defined (SIGMAX)
# define EV_NSIG (SIGMAX+1)
#elif defined (SIG_MAX)
# define EV_NSIG (SIG_MAX+1)
#elif defined (_SIG_MAX)
# define EV_NSIG (_SIG_MAX+1)
#elif defined (MAXSIG)
# define EV_NSIG (MAXSIG+1)
#elif defined (MAX_SIG)
# define EV_NSIG (MAX_SIG+1)
#elif defined (SIGARRAYSIZE)
# define EV_NSIG SIGARRAYSIZE /* Assume ary[SIGARRAYSIZE] */
#elif defined (_sys_nsig)
# define EV_NSIG (_sys_nsig) /* Solaris 2.5 */
#else
# error "unable to find value for NSIG, please report"
/* to make it compile regardless, just remove the above line */
# define EV_NSIG 65
#endif

#ifndef EV_USE_CLOCK_SYSCALL
# if __linux && __GLIBC__ >= 2
#  define EV_USE_CLOCK_SYSCALL 1
# else
#  define EV_USE_CLOCK_SYSCALL 0
# endif
#endif

#ifndef EV_USE_MONOTONIC
# if defined (_POSIX_MONOTONIC_CLOCK) && _POSIX_MONOTONIC_CLOCK >= 0
#  define EV_USE_MONOTONIC 1
# else
#  define EV_USE_MONOTONIC 0
# endif
#endif

#ifndef EV_USE_REALTIME
# define EV_USE_REALTIME !EV_USE_CLOCK_SYSCALL
#endif

#ifndef EV_USE_NANOSLEEP
# if _POSIX_C_SOURCE >= 199309L
#  define EV_USE_NANOSLEEP 1
# else
#  define EV_USE_NANOSLEEP 0
# endif
#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
# if __linux && (__GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 4))
#  define EV_USE_EPOLL 1
# else
#  define EV_USE_EPOLL 0
# endif
#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
# if __linux && (__GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 4))
#  define EV_USE_INOTIFY 1
# else
#  define EV_USE_INOTIFY 0
# endif
#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 EV_USE_EVENTFD
# if __linux && (__GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 7))
#  define EV_USE_EVENTFD 1
# else
#  define EV_USE_EVENTFD 0
# endif
#endif

#ifndef EV_USE_SIGNALFD
# if __linux && (__GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 7))
#  define EV_USE_SIGNALFD 1
# else
#  define EV_USE_SIGNALFD 0
# endif
#endif

#if 0 /* debugging */
# define EV_VERIFY 3
# define EV_USE_4HEAP 1
# define EV_HEAP_CACHE_AT 1
#endif

#ifndef EV_VERIFY
# define EV_VERIFY !EV_MINIMAL
#endif

#ifndef EV_USE_4HEAP
# define EV_USE_4HEAP !EV_MINIMAL
#endif

#ifndef EV_HEAP_CACHE_AT
# define EV_HEAP_CACHE_AT !EV_MINIMAL
#endif

/* on linux, we can use a (slow) syscall to avoid a dependency on pthread, */
/* which makes programs even slower. might work on other unices, too. */
#if EV_USE_CLOCK_SYSCALL
# include <syscall.h>
# ifdef SYS_clock_gettime
#  define clock_gettime(id, ts) syscall (SYS_clock_gettime, (id), (ts))
#  undef EV_USE_MONOTONIC
#  define EV_USE_MONOTONIC 1
# else
#  undef EV_USE_CLOCK_SYSCALL
#  define EV_USE_CLOCK_SYSCALL 0
# endif
#endif

/* this block fixes any misconfiguration where we know we run into trouble otherwise */

#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_NANOSLEEP
# ifndef _WIN32
#  include <sys/select.h>
# endif
#endif

#if EV_USE_INOTIFY
# include <sys/utsname.h>
# include <sys/statfs.h>
# include <sys/inotify.h>
/* some very old inotify.h headers don't have IN_DONT_FOLLOW */
# ifndef IN_DONT_FOLLOW
#  undef EV_USE_INOTIFY
#  define EV_USE_INOTIFY 0
# endif
#endif

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

#if EV_USE_EVENTFD
/* our minimum requirement is glibc 2.7 which has the stub, but not the header */
# include <stdint.h>
# ifndef EFD_NONBLOCK
#  define EFD_NONBLOCK O_NONBLOCK
# endif
# ifndef EFD_CLOEXEC
#  ifdef O_CLOEXEC
#   define EFD_CLOEXEC O_CLOEXEC
#  else
#   define EFD_CLOEXEC 02000000
#  endif
# endif
# ifdef __cplusplus
extern "C" {
# endif
int eventfd (unsigned int initval, int flags);
# ifdef __cplusplus
}
# endif
#endif

#if EV_USE_SIGNALFD
/* our minimum requirement is glibc 2.7 which has the stub, but not the header */
# include <stdint.h>
# ifndef SFD_NONBLOCK
#  define SFD_NONBLOCK O_NONBLOCK
# endif
# ifndef SFD_CLOEXEC
#  ifdef O_CLOEXEC
#   define SFD_CLOEXEC O_CLOEXEC
#  else
#   define SFD_CLOEXEC 02000000
#  endif
# endif
# ifdef __cplusplus
extern "C" {
# endif
int signalfd (int fd, const sigset_t *mask, int flags);

struct signalfd_siginfo
{
  uint32_t ssi_signo;
  char pad[128 - sizeof (uint32_t)];
};
# ifdef __cplusplus
}
# endif
#endif


/**/

#if EV_VERIFY >= 3
# define EV_FREQUENT_CHECK ev_loop_verify (EV_A)
#else
# define EV_FREQUENT_CHECK do { } while (0)
#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) */

#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 && __GNUC__ < 2
#  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)

#if EV_MINPRI == EV_MAXPRI
# define ABSPRI(w) (((W)w), 0)
#else
# define ABSPRI(w) (((W)w)->priority - EV_MINPRI)
#endif

#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;

#define ev_active(w) ((W)(w))->active
#define ev_at(w) ((WT)(w))->at

#if EV_USE_REALTIME
/* sig_atomic_t is used to avoid per-thread variables or locking but still */
/* giving it a reasonably high chance of working on typical architetcures */
static EV_ATOMIC_T have_realtime; /* did clock_gettime (CLOCK_REALTIME) work? */
#endif

#if EV_USE_MONOTONIC
static EV_ATOMIC_T have_monotonic; /* did clock_gettime (CLOCK_MONOTONIC) work? */
#endif

#ifndef EV_FD_TO_WIN32_HANDLE
# define EV_FD_TO_WIN32_HANDLE(fd) _get_osfhandle (fd)
#endif
#ifndef EV_WIN32_HANDLE_TO_FD
# define EV_WIN32_HANDLE_TO_FD(handle) _open_osfhandle (fd, 0)
#endif
#ifndef EV_WIN32_CLOSE_FD
# define EV_WIN32_CLOSE_FD(fd) close (fd)
#endif

#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
ev_syserr (const char *msg)
{
  if (!msg)
    msg = "(libev) system error";

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

static void *
ev_realloc_emul (void *ptr, long size)
{
  /* some systems, notably openbsd and darwin, fail to properly
   * implement realloc (x, 0) (as required by both ansi c-98 and
   * the single unix specification, so work around them here.
   */

  if (size)
    return realloc (ptr, size);

  free (ptr);
  return 0;
}

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

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

inline_speed void *
ev_realloc (void *ptr, long size)
{
  ptr = alloc (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)

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

/* set in reify when reification needed */
#define EV_ANFD_REIFY 1

/* file descriptor info structure */
typedef struct
{
  WL head;
  unsigned char events; /* the events watched for */
  unsigned char reify;  /* flag set when this ANFD needs reification (EV_ANFD_REIFY, EV__IOFDSET) */
  unsigned char emask;  /* the epoll backend stores the actual kernel mask in here */
  unsigned char unused;
#if EV_USE_EPOLL
  unsigned int egen;    /* generation counter to counter epoll bugs */
#endif
#if EV_SELECT_IS_WINSOCKET
  SOCKET handle;
#endif
} ANFD;

/* stores the pending event set for a given watcher */
typedef struct
{
  W w;
  int events; /* the pending event set for the given watcher */
} ANPENDING;

#if EV_USE_INOTIFY
/* hash table entry per inotify-id */
typedef struct
{
  WL head;
} ANFS;
#endif

/* Heap Entry */
#if EV_HEAP_CACHE_AT
  /* a heap element */
  typedef struct {
    ev_tstamp at;
    WT w;
  } ANHE;

  #define ANHE_w(he)        (he).w     /* access watcher, read-write */
  #define ANHE_at(he)       (he).at    /* access cached at, read-only */
  #define ANHE_at_cache(he) (he).at = (he).w->at /* update at from watcher */
#else
  /* a heap element */
  typedef WT ANHE;

  #define ANHE_w(he)        (he)
  #define ANHE_at(he)       (he)->at
  #define ANHE_at_cache(he)
#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

#if EV_MINIMAL < 2
# define EV_RELEASE_CB if (expect_false (release_cb)) release_cb (EV_A)
# define EV_ACQUIRE_CB if (expect_false (acquire_cb)) acquire_cb (EV_A)
# define EV_INVOKE_PENDING invoke_cb (EV_A)
#else
# define EV_RELEASE_CB (void)0
# define EV_ACQUIRE_CB (void)0
# define EV_INVOKE_PENDING ev_invoke_pending (EV_A)
#endif

#define EVUNLOOP_RECURSE 0x80

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

#ifndef EV_HAVE_EV_TIME
ev_tstamp
ev_time (void)
{
#if EV_USE_REALTIME
  if (expect_true (have_realtime))
    {
      struct timespec ts;
      clock_gettime (CLOCK_REALTIME, &ts);
      return ts.tv_sec + ts.tv_nsec * 1e-9;
    }
#endif

  struct timeval tv;
  gettimeofday (&tv, 0);
  return tv.tv_sec + tv.tv_usec * 1e-6;
}
#endif

inline_size ev_tstamp
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

void
ev_sleep (ev_tstamp delay)
{
  if (delay > 0.)
    {
#if EV_USE_NANOSLEEP
      struct timespec ts;

      ts.tv_sec  = (time_t)delay;
      ts.tv_nsec = (long)((delay - (ev_tstamp)(ts.tv_sec)) * 1e9);

      nanosleep (&ts, 0);
#elif defined(_WIN32)
      Sleep ((unsigned long)(delay * 1e3));
#else
      struct timeval tv;

      tv.tv_sec  = (time_t)delay;
      tv.tv_usec = (long)((delay - (ev_tstamp)(tv.tv_sec)) * 1e6);

      /* here we rely on sys/time.h + sys/types.h + unistd.h providing select */
      /* something not guaranteed by newer posix versions, but guaranteed */
      /* by older ones */
      select (0, 0, 0, 0, &tv);
#endif
    }
}

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

#define MALLOC_ROUND 4096 /* prefer to allocate in chunks of this size, must be 2**n and >> 4 longs */

/* find a suitable new size for the given array, */
/* hopefully by rounding to a ncie-to-malloc size */
inline_size int
array_nextsize (int elem, int cur, int cnt)
{
  int ncur = cur + 1;

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

  /* if size is large, round to MALLOC_ROUND - 4 * longs to accomodate malloc overhead */
  if (elem * ncur > MALLOC_ROUND - sizeof (void *) * 4)
    {
      ncur *= elem;
      ncur = (ncur + elem + (MALLOC_ROUND - 1) + sizeof (void *) * 4) & ~(MALLOC_ROUND - 1);
      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_init_zero(base,count)	\
  memset ((void *)(base), 0, sizeof (*(base)) * (count))