gvpe/src/iom.C

/*
    iom.C -- generic I/O multiplexer
    Copyright (C) 2003, 2004 Marc Lehmann <gvpe@schmorp.de>
 
    This file is part of GVPE.

    GVPE is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.
 
    This program 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 General Public License for more details.
 
    You should have received a copy of the GNU General Public License
    along with gvpe; if not, write to the Free Software
    Foundation, Inc. 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/

#include "iom.h"

#include <cstdio>
#include <cstdlib>
#include <cerrno>

#include <sys/time.h>

#include <assert.h>

#if 1 // older unices need these includes for select (2)
# include <unistd.h>
# include <sys/types.h>
# include <time.h>
#endif

// for IOM_SIG
#if IOM_SIG
# include <csignal>
# include <fcntl.h>
#endif

// if the BSDs would at least be marginally POSIX-compatible.. *sigh*
// until that happens, sys/select.h must come last
#include <sys/select.h>

// TSTAMP_MAX must still fit into a positive struct timeval
#define TSTAMP_MAX (double)(1UL<<31)

#define TIMEVAL timeval
#define TV_FRAC tv_usec
#define TV_MULT 1000000L

#if IOM_IO
static io_manager_vec<io_watcher>    iow;
#endif
#if IOM_CHECK
static io_manager_vec<check_watcher> cw;
#endif
#if IOM_TIME
static io_manager_vec<time_watcher>  tw;
#endif
#if IOM_IDLE
static io_manager_vec<idle_watcher>  iw;
#endif
#if IOM_SIG
static int sigpipe[2]; // signal signalling pipe
static sigset_t sigs;
struct sig_vec : io_manager_vec<sig_watcher> {
  int pending;
  sig_vec ()
    : pending (false)
    { }
};
static vector<sig_vec *> sw;
#endif

// this is a dummy time watcher to ensure that the first
// time watcher is _always_ valid, this gets rid of a lot
// of null-pointer-checks
// (must come _before_ iom is being defined)
static struct tw0 : time_watcher
  {
    void cb (time_watcher &w)
    {
      // should never get called
      // reached end-of-time, or tstamp has a bogus definition,
      // or compiler initialisation order broken, or something else :)
      abort ();
    }

    tw0 ()
      : time_watcher (this, &tw0::cb)
      { }
  } tw0;

tstamp NOW;

#if IOM_TIME
tstamp io_manager::now ()
{
  struct timeval tv;

  gettimeofday (&tv, 0);
  return (tstamp)tv.tv_sec + (tstamp)tv.tv_usec / 1000000.;
}

void io_manager::set_now ()
{
  NOW = now ();
}
#endif

static bool iom_valid;

// used for initialisation only
static struct init {
  init ()
  {
#if IOM_SIG
    sigemptyset (&sigs);

    if (pipe (sigpipe))
      {
        perror ("io_manager: unable to create signal pipe, aborting.");
        abort ();
      }

    fcntl (sigpipe[0], F_SETFL, O_NONBLOCK); fcntl (sigpipe[0], F_SETFD, FD_CLOEXEC);
    fcntl (sigpipe[1], F_SETFL, O_NONBLOCK); fcntl (sigpipe[1], F_SETFD, FD_CLOEXEC);
#endif

    iom_valid = true;

#if IOM_TIME
    io_manager::set_now ();

    tw0.start (TSTAMP_MAX);
#endif
  }

  static void required ();
} init;

void
init::required ()
{
  if (!iom_valid)
    {
      write (2, "io_manager: early registration attempt, aborting.\n",
                sizeof ("io_manager: early registration attempt, aborting.\n") - 1);
      abort ();
    }
}

template<class watcher>
void io_manager::reg (watcher &w, io_manager_vec<watcher> &queue)
{
  init::required ();

  if (!w.active)
    {
      queue.push_back (&w);
      w.active = queue.size ();
    }
}

template<class watcher>
void io_manager::unreg (watcher &w, io_manager_vec<watcher> &queue)
{
  if (!iom_valid)
    return;

  if (w.active)
    {
      queue [w.active - 1] = 0;
      w.active = 0;
    }
}

#if IOM_TIME
void time_watcher::trigger ()
{
  call (*this);
  io_manager::reg (*this);
}

void io_manager::reg   (time_watcher &w)  { io_manager::reg   (w, tw); }
void io_manager::unreg (time_watcher &w)  { io_manager::unreg (w, tw); }
#endif

#if IOM_IO
void io_manager::reg   (io_watcher &w)    { io_manager::reg   (w, iow); }
void io_manager::unreg (io_watcher &w)    { io_manager::unreg (w, iow); }
#endif

#if IOM_CHECK
void io_manager::reg   (check_watcher &w) { io_manager::reg   (w, cw); }
void io_manager::unreg (check_watcher &w) { io_manager::unreg (w, cw); }
#endif

#if IOM_IDLE
void io_manager::reg   (idle_watcher &w)  { io_manager::reg   (w, iw); }
void io_manager::unreg (idle_watcher &w)  { io_manager::unreg (w, iw); }
#endif

#if IOM_SIG
static void
sighandler (int signum)
{
  sw [signum - 1]->pending = true;

  // we use a pipe for signal notifications, as most current
  // OSes (Linux...) do not implement pselect correctly. ugh.
  char ch = signum; // actual content not used
  write (sigpipe[1], &ch, 1);
}

void io_manager::reg (sig_watcher &w)
{
  assert (0 < w.signum);

  sw.reserve (w.signum);

  while (sw.size () < w.signum) // pathetic
    sw.push_back (0);

  sig_vec *&sv = sw[w.signum - 1];

  if (!sv)
    {
      sv = new sig_vec;

      sigaddset (&sigs, w.signum);
      sigprocmask (SIG_BLOCK, &sigs, NULL);

      struct sigaction sa;
      sa.sa_handler = sighandler;
      sigfillset (&sa.sa_mask);
      sa.sa_flags = SA_RESTART;

      if (sigaction (w.signum, &sa, 0))
        {
          perror ("io_manager: error while installing signal handler, ignoring.");
          abort ();
        }

    }

  io_manager::reg (w, *sv);
}

void io_manager::unreg (sig_watcher &w)
{
  if (!w.active)
    return;

  assert (0 < w.signum && w.signum <= sw.size ());
  
  io_manager::unreg (w, *sw[w.signum - 1]);
}

void sig_watcher::start (int signum)
{
  stop ();
  this->signum = signum;
  io_manager::reg (*this);
}
#endif

void io_manager::loop ()
{
  init::required ();

#if IOM_TIME
  set_now ();
#endif

  for (;;)
    {

#if IOM_TIME
      // call pending time watchers
      {
        bool activity;

        do
          {
            activity = false;

            for (int i = tw.size (); i--; )
              if (!tw[i])
                tw.erase_unordered (i);
              else if (tw[i]->at <= NOW)
                {
                  time_watcher &w = *tw[i];
                  
                  unreg (w);
                  w.call (w);

                  activity = true;
                }
          }
        while (activity);
      }
#endif

#if IOM_CHECK
      // call all check watchers
      for (int i = cw.size (); i--; )
        if (!cw[i])
          cw.erase_unordered (i);
        else
          cw[i]->call (*cw[i]);
#endif

      struct TIMEVAL *to = 0;
      struct TIMEVAL tval;

#if IOM_IDLE
      if (iw.size ())
        {
          tval.tv_sec  = 0;
          tval.TV_FRAC = 0;
          to = &tval;
        }
      else
#endif
        {
#if IOM_TIME
          // find earliest active watcher
          time_watcher *next = tw[0]; // the first time-watcher must exist at ALL times

          for (io_manager_vec<time_watcher>::const_iterator i = tw.end (); i-- > tw.begin (); )
            if (*i && (*i)->at < next->at)
              next = *i;

          if (next->at > NOW && next != tw[0])
            {
              double diff = next->at - NOW;
              tval.tv_sec  = (int)diff;
              tval.TV_FRAC = (int) ((diff - tval.tv_sec) * TV_MULT);
              to = &tval;
            }
        }
#endif

#if IOM_IO || IOM_SIG
      fd_set rfd, wfd;

      FD_ZERO (&rfd);
      FD_ZERO (&wfd);

      int fds = 0;

# if IOM_IO
      for (io_manager_vec<io_watcher>::const_iterator i = iow.end (); i-- > iow.begin (); )
        if (*i)
          {
            if ((*i)->events & EVENT_READ ) FD_SET ((*i)->fd, &rfd);
            if ((*i)->events & EVENT_WRITE) FD_SET ((*i)->fd, &wfd);

            if ((*i)->fd >= fds) fds = (*i)->fd + 1;
          }
# endif

      if (!to && !fds) //TODO: also check idle_watchers and check_watchers?
        break; // no events

# if IOM_SIG
      FD_SET (sigpipe[0], &rfd);
      if (sigpipe[0] >= fds) fds = sigpipe[0] + 1;
# endif

# if IOM_SIG
      // there is no race, as we use a pipe for signals, so select
      // will return if a signal is caught.
      sigprocmask (SIG_UNBLOCK, &sigs, NULL);
# endif
      fds = select (fds, &rfd, &wfd, NULL, to);
# if IOM_SIG
      sigprocmask (SIG_BLOCK, &sigs, NULL);
# endif

# if IOM_TIME
      {
        // update time, try to compensate for gross non-monotonic time changes
        tstamp diff = NOW;
        set_now ();
        diff = NOW - diff;

        if (diff < 0)
          for (io_manager_vec<time_watcher>::const_iterator i = tw.end (); i-- > tw.begin (); )
            if (*i)
              (*i)->at += diff;
      }
# endif

      if (fds > 0)
        {
# if IOM_SIG
          if (FD_ISSET (sigpipe[0], &rfd))
            {
              char ch;

              while (read (sigpipe[0], &ch, 1) > 0)
                ;

              for (vector<sig_vec *>::iterator svp = sw.end (); svp-- > sw.begin (); )
                if (*svp && (*svp)->pending)
                  {
                    sig_vec &sv = **svp;
                    for (int i = sv.size (); i--; )
                      if (!sv[i])
                        sv.erase_unordered (i);
                      else
                        sv[i]->call (*sv[i]);

                    sv.pending = false;
                  }
            }
# endif

# if IOM_IO
          for (int i = iow.size (); i--; )
            if (!iow[i])
              iow.erase_unordered (i);
            else
              {
                io_watcher &w = *iow[i];
                short revents = w.events;

                if (!FD_ISSET (w.fd, &rfd)) revents &= ~EVENT_READ;
                if (!FD_ISSET (w.fd, &wfd)) revents &= ~EVENT_WRITE;

                if (revents)
                  w.call (w, revents);
              }
#endif
        }
      else if (fds < 0 && errno != EINTR)
        {
          perror ("io_manager: fatal error while waiting for I/O or time event, aborting.");
          abort ();
        }
#if IOM_IDLE
      else
        for (int i = iw.size (); i--; )
          if (!iw[i])
            iw.erase_unordered (i);
          else
            iw[i]->call (*iw[i]);
#endif

#elif IOM_TIME
      if (!to)
        break;

      select (0, 0, 0, 0, &to);
      set_now ();
#else
      break;
#endif
    }
}

Revision:	1.30
Committed:	Thu Mar 3 16:54:34 2005 UTC (19 years, 4 months ago) by pcg
Content type:	text/plain
Branch:	MAIN
Changes since 1.29:	+5 -3 lines
Log Message:	* empty log message *
#	User	Rev	Content
1	pcg	1.1	/*
2	pcg	1.23	iom.C -- generic I/O multiplexer
3	pcg	1.30	Copyright (C) 2003, 2004 Marc Lehmann <gvpe@schmorp.de>
4	pcg	1.1
5	pcg	1.30	This file is part of GVPE.
6
7			GVPE is free software; you can redistribute it and/or modify
8	pcg	1.1	it under the terms of the GNU General Public License as published by
9			the Free Software Foundation; either version 2 of the License, or
10			(at your option) any later version.
11
12			This program is distributed in the hope that it will be useful,
13			but WITHOUT ANY WARRANTY; without even the implied warranty of
14			MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15			GNU General Public License for more details.
16
17			You should have received a copy of the GNU General Public License
18	pcg	1.30	along with gvpe; if not, write to the Free Software
19	pcg	1.1	Foundation, Inc. 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20			*/
21
22	pcg	1.21	#include "iom.h"
23
24	pcg	1.13	#include <cstdio>
25			#include <cstdlib>
26			#include <cerrno>
27	pcg	1.1
28	pcg	1.15	#include <sys/time.h>
29
30	pcg	1.20	#include <assert.h>
31
32	pcg	1.18	#if 1 // older unices need these includes for select (2)
33	pcg	1.15	# include <unistd.h>
34			# include <sys/types.h>
35	pcg	1.21	# include <time.h>
36			#endif
37
38			// for IOM_SIG
39			#if IOM_SIG
40	pcg	1.28	# include <csignal>
41	pcg	1.21	# include <fcntl.h>
42	pcg	1.15	#endif
43
44			// if the BSDs would at least be marginally POSIX-compatible.. sigh
45			// until that happens, sys/select.h must come last
46	pcg	1.13	#include <sys/select.h>
47	pcg	1.1
48	pcg	1.21	// TSTAMP_MAX must still fit into a positive struct timeval
49			#define TSTAMP_MAX (double)(1UL<<31)
50	pcg	1.20
51	pcg	1.21	#define TIMEVAL timeval
52			#define TV_FRAC tv_usec
53			#define TV_MULT 1000000L
54	pcg	1.11
55	pcg	1.21	#if IOM_IO
56			static io_manager_vec<io_watcher> iow;
57			#endif
58			#if IOM_CHECK
59			static io_manager_vec<check_watcher> cw;
60			#endif
61			#if IOM_TIME
62			static io_manager_vec<time_watcher> tw;
63			#endif
64			#if IOM_IDLE
65			static io_manager_vec<idle_watcher> iw;
66			#endif
67			#if IOM_SIG
68			static int sigpipe[2]; // signal signalling pipe
69			static sigset_t sigs;
70			struct sig_vec : io_manager_vec<sig_watcher> {
71			int pending;
72			sig_vec ()
73			: pending (false)
74			{ }
75			};
76			static vector<sig_vec *> sw;
77			#endif
78	pcg	1.1
79	pcg	1.14	// this is a dummy time watcher to ensure that the first
80			// time watcher is _always_ valid, this gets rid of a lot
81			// of null-pointer-checks
82			// (must come _before_ iom is being defined)
83	pcg	1.18	static struct tw0 : time_watcher
84	pcg	1.14	{
85	pcg	1.18	void cb (time_watcher &w)
86			{
87			// should never get called
88			// reached end-of-time, or tstamp has a bogus definition,
89	pcg	1.21	// or compiler initialisation order broken, or something else :)
90	pcg	1.18	abort ();
91			}
92	pcg	1.14
93	pcg	1.18	tw0 ()
94	pcg	1.21	: time_watcher (this, &tw0::cb)
95			{ }
96	pcg	1.20	} tw0;
97	pcg	1.14
98	pcg	1.10	tstamp NOW;
99	pcg	1.21
100			#if IOM_TIME
101	pcg	1.26	tstamp io_manager::now ()
102	pcg	1.21	{
103			struct timeval tv;
104
105			gettimeofday (&tv, 0);
106	pcg	1.26	return (tstamp)tv.tv_sec + (tstamp)tv.tv_usec / 1000000.;
107			}
108
109			void io_manager::set_now ()
110			{
111			NOW = now ();
112	pcg	1.21	}
113			#endif
114
115	pcg	1.13	static bool iom_valid;
116	pcg	1.21
117			// used for initialisation only
118			static struct init {
119			init ()
120			{
121			#if IOM_SIG
122			sigemptyset (&sigs);
123
124			if (pipe (sigpipe))
125			{
126			perror ("io_manager: unable to create signal pipe, aborting.");
127			abort ();
128			}
129
130	pcg	1.26	fcntl (sigpipe[0], F_SETFL, O_NONBLOCK); fcntl (sigpipe[0], F_SETFD, FD_CLOEXEC);
131			fcntl (sigpipe[1], F_SETFL, O_NONBLOCK); fcntl (sigpipe[1], F_SETFD, FD_CLOEXEC);
132	pcg	1.21	#endif
133
134			iom_valid = true;
135
136			#if IOM_TIME
137	pcg	1.26	io_manager::set_now ();
138	pcg	1.21
139			tw0.start (TSTAMP_MAX);
140			#endif
141			}
142
143			static void required ();
144			} init;
145
146			void
147			init::required ()
148			{
149			if (!iom_valid)
150			{
151			write (2, "io_manager: early registration attempt, aborting.\n",
152			sizeof ("io_manager: early registration attempt, aborting.\n") - 1);
153			abort ();
154			}
155			}
156	pcg	1.10
157	pcg	1.13	template<class watcher>
158	pcg	1.21	void io_manager::reg (watcher &w, io_manager_vec<watcher> &queue)
159	pcg	1.4	{
160	pcg	1.21	init::required ();
161	pcg	1.4
162	pcg	1.21	if (!w.active)
163	pcg	1.11	{
164	pcg	1.21	queue.push_back (&w);
165			w.active = queue.size ();
166	pcg	1.11	}
167	pcg	1.10	}
168
169	pcg	1.13	template<class watcher>
170	pcg	1.21	void io_manager::unreg (watcher &w, io_manager_vec<watcher> &queue)
171	pcg	1.10	{
172	pcg	1.13	if (!iom_valid)
173			return;
174	pcg	1.10
175	pcg	1.21	if (w.active)
176	pcg	1.11	{
177	pcg	1.21	queue [w.active - 1] = 0;
178			w.active = 0;
179	pcg	1.11	}
180	pcg	1.1	}
181
182	pcg	1.13	#if IOM_TIME
183			void time_watcher::trigger ()
184	pcg	1.1	{
185	pcg	1.13	call (*this);
186	pcg	1.21	io_manager::reg (*this);
187	pcg	1.1	}
188
189	pcg	1.21	void io_manager::reg (time_watcher &w) { io_manager::reg (w, tw); }
190			void io_manager::unreg (time_watcher &w) { io_manager::unreg (w, tw); }
191	pcg	1.13	#endif
192	pcg	1.6
193	pcg	1.13	#if IOM_IO
194	pcg	1.21	void io_manager::reg (io_watcher &w) { io_manager::reg (w, iow); }
195			void io_manager::unreg (io_watcher &w) { io_manager::unreg (w, iow); }
196	pcg	1.13	#endif
197	pcg	1.7
198	pcg	1.13	#if IOM_CHECK
199	pcg	1.21	void io_manager::reg (check_watcher &w) { io_manager::reg (w, cw); }
200			void io_manager::unreg (check_watcher &w) { io_manager::unreg (w, cw); }
201	pcg	1.13	#endif
202	pcg	1.1
203	pcg	1.13	#if IOM_IDLE
204	pcg	1.21	void io_manager::reg (idle_watcher &w) { io_manager::reg (w, iw); }
205			void io_manager::unreg (idle_watcher &w) { io_manager::unreg (w, iw); }
206	pcg	1.13	#endif
207	pcg	1.1
208	pcg	1.21	#if IOM_SIG
209			static void
210			sighandler (int signum)
211	pcg	1.1	{
212	pcg	1.21	sw [signum - 1]->pending = true;
213	pcg	1.1
214	pcg	1.21	// we use a pipe for signal notifications, as most current
215			// OSes (Linux...) do not implement pselect correctly. ugh.
216			char ch = signum; // actual content not used
217			write (sigpipe[1], &ch, 1);
218	pcg	1.20	}
219
220	pcg	1.21	void io_manager::reg (sig_watcher &w)
221	pcg	1.20	{
222	pcg	1.21	assert (0 < w.signum);
223	pcg	1.20
224	pcg	1.21	sw.reserve (w.signum);
225	pcg	1.20
226	pcg	1.21	while (sw.size () < w.signum) // pathetic
227			sw.push_back (0);
228	pcg	1.20
229	pcg	1.21	sig_vec *&sv = sw[w.signum - 1];
230	pcg	1.20
231			if (!sv)
232			{
233			sv = new sig_vec;
234
235	pcg	1.21	sigaddset (&sigs, w.signum);
236			sigprocmask (SIG_BLOCK, &sigs, NULL);
237
238	pcg	1.20	struct sigaction sa;
239	pcg	1.21	sa.sa_handler = sighandler;
240	pcg	1.20	sigfillset (&sa.sa_mask);
241	pcg	1.21	sa.sa_flags = SA_RESTART;
242	pcg	1.20
243	pcg	1.21	if (sigaction (w.signum, &sa, 0))
244	pcg	1.20	{
245	pcg	1.21	perror ("io_manager: error while installing signal handler, ignoring.");
246	pcg	1.20	abort ();
247			}
248	pcg	1.21
249	pcg	1.20	}
250
251	pcg	1.21	io_manager::reg (w, *sv);
252	pcg	1.20	}
253
254	pcg	1.21	void io_manager::unreg (sig_watcher &w)
255	pcg	1.20	{
256	pcg	1.21	if (!w.active)
257			return;
258
259			assert (0 < w.signum && w.signum <= sw.size ());
260	pcg	1.20
261	pcg	1.21	io_manager::unreg (w, *sw[w.signum - 1]);
262	pcg	1.20	}
263
264			void sig_watcher::start (int signum)
265			{
266			stop ();
267			this->signum = signum;
268	pcg	1.21	io_manager::reg (*this);
269	pcg	1.20	}
270			#endif
271	pcg	1.21
272	pcg	1.1	void io_manager::loop ()
273			{
274	pcg	1.21	init::required ();
275
276	pcg	1.13	#if IOM_TIME
277	pcg	1.1	set_now ();
278	pcg	1.13	#endif
279	pcg	1.1
280	pcg	1.4	for (;;)
281	pcg	1.1	{
282	pcg	1.13
283			#if IOM_TIME
284	pcg	1.22	// call pending time watchers
285			{
286			bool activity;
287	pcg	1.7
288	pcg	1.22	do
289			{
290			activity = false;
291	pcg	1.13
292	pcg	1.22	for (int i = tw.size (); i--; )
293			if (!tw[i])
294			tw.erase_unordered (i);
295	pcg	1.24	else if (tw[i]->at <= NOW)
296	pcg	1.22	{
297			time_watcher &w = *tw[i];
298
299			unreg (w);
300			w.call (w);
301	pcg	1.13
302	pcg	1.22	activity = true;
303	pcg	1.13	}
304	pcg	1.22	}
305			while (activity);
306			}
307	pcg	1.13	#endif
308	pcg	1.1
309	pcg	1.13	#if IOM_CHECK
310	pcg	1.22	// call all check watchers
311	pcg	1.13	for (int i = cw.size (); i--; )
312			if (!cw[i])
313			cw.erase_unordered (i);
314			else
315			cw[i]->call (*cw[i]);
316	pcg	1.22	#endif
317	pcg	1.17
318	pcg	1.22	struct TIMEVAL *to = 0;
319			struct TIMEVAL tval;
320
321			#if IOM_IDLE
322			if (iw.size ())
323	pcg	1.17	{
324			tval.tv_sec = 0;
325	pcg	1.21	tval.TV_FRAC = 0;
326	pcg	1.17	to = &tval;
327			}
328	pcg	1.22	else
329			#endif
330			{
331			#if IOM_TIME
332			// find earliest active watcher
333			time_watcher *next = tw[0]; // the first time-watcher must exist at ALL times
334
335			for (io_manager_vec<time_watcher>::const_iterator i = tw.end (); i-- > tw.begin (); )
336			if (i && (i)->at < next->at)
337			next = *i;
338
339			if (next->at > NOW && next != tw[0])
340			{
341			double diff = next->at - NOW;
342			tval.tv_sec = (int)diff;
343			tval.TV_FRAC = (int) ((diff - tval.tv_sec) * TV_MULT);
344			to = &tval;
345			}
346			}
347	pcg	1.13	#endif
348
349	pcg	1.21	#if IOM_IO \|\| IOM_SIG
350	pcg	1.18	fd_set rfd, wfd;
351	pcg	1.7
352	pcg	1.13	FD_ZERO (&rfd);
353			FD_ZERO (&wfd);
354	pcg	1.7
355	pcg	1.13	int fds = 0;
356
357	pcg	1.21	# if IOM_IO
358	pcg	1.22	for (io_manager_vec<io_watcher>::const_iterator i = iow.end (); i-- > iow.begin (); )
359	pcg	1.13	if (*i)
360			{
361			if ((i)->events & EVENT_READ ) FD_SET ((i)->fd, &rfd);
362			if ((i)->events & EVENT_WRITE) FD_SET ((i)->fd, &wfd);
363	pcg	1.1
364	pcg	1.13	if ((i)->fd >= fds) fds = (i)->fd + 1;
365			}
366	pcg	1.21	# endif
367	pcg	1.1
368	pcg	1.22	if (!to && !fds) //TODO: also check idle_watchers and check_watchers?
369	pcg	1.13	break; // no events
370	pcg	1.1
371	pcg	1.21	# if IOM_SIG
372			FD_SET (sigpipe[0], &rfd);
373			if (sigpipe[0] >= fds) fds = sigpipe[0] + 1;
374			# endif
375
376			# if IOM_SIG
377			// there is no race, as we use a pipe for signals, so select
378			// will return if a signal is caught.
379			sigprocmask (SIG_UNBLOCK, &sigs, NULL);
380			# endif
381	pcg	1.19	fds = select (fds, &rfd, &wfd, NULL, to);
382	pcg	1.21	# if IOM_SIG
383			sigprocmask (SIG_BLOCK, &sigs, NULL);
384			# endif
385
386	pcg	1.13	# if IOM_TIME
387	pcg	1.29	{
388			// update time, try to compensate for gross non-monotonic time changes
389			tstamp diff = NOW;
390			set_now ();
391			diff = NOW - diff;
392
393			if (diff < 0)
394			for (io_manager_vec<time_watcher>::const_iterator i = tw.end (); i-- > tw.begin (); )
395			if (*i)
396			(*i)->at += diff;
397			}
398	pcg	1.13	# endif
399	pcg	1.1
400	pcg	1.13	if (fds > 0)
401	pcg	1.21	{
402			# if IOM_SIG
403			if (FD_ISSET (sigpipe[0], &rfd))
404	pcg	1.13	{
405	pcg	1.21	char ch;
406
407			while (read (sigpipe[0], &ch, 1) > 0)
408			;
409	pcg	1.13
410	pcg	1.25	for (vector<sig_vec *>::iterator svp = sw.end (); svp-- > sw.begin (); )
411	pcg	1.21	if (svp && (svp)->pending)
412			{
413			sig_vec &sv = **svp;
414			for (int i = sv.size (); i--; )
415			if (!sv[i])
416			sv.erase_unordered (i);
417			else
418			sv[i]->call (*sv[i]);
419	pcg	1.13
420	pcg	1.21	sv.pending = false;
421			}
422	pcg	1.13	}
423	pcg	1.21	# endif
424
425			# if IOM_IO
426			for (int i = iow.size (); i--; )
427			if (!iow[i])
428			iow.erase_unordered (i);
429			else
430			{
431	pcg	1.27	io_watcher &w = *iow[i];
432			short revents = w.events;
433	pcg	1.21
434	pcg	1.27	if (!FD_ISSET (w.fd, &rfd)) revents &= ~EVENT_READ;
435			if (!FD_ISSET (w.fd, &wfd)) revents &= ~EVENT_WRITE;
436	pcg	1.21
437			if (revents)
438	pcg	1.27	w.call (w, revents);
439	pcg	1.21	}
440			#endif
441			}
442	pcg	1.13	else if (fds < 0 && errno != EINTR)
443			{
444	pcg	1.21	perror ("io_manager: fatal error while waiting for I/O or time event, aborting.");
445	pcg	1.13	abort ();
446			}
447			#if IOM_IDLE
448			else
449			for (int i = iw.size (); i--; )
450			if (!iw[i])
451			iw.erase_unordered (i);
452			else
453			iw[i]->call (*iw[i]);
454			#endif
455
456			#elif IOM_TIME
457			if (!to)
458			break;
459	pcg	1.9
460	pcg	1.13	select (0, 0, 0, 0, &to);
461			set_now ();
462			#else
463			break;
464			#endif
465	pcg	1.1	}
466			}
467