rxvt-unicode/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. 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  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>

#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:	Tue Nov 29 19:22:48 2005 UTC (18 years, 5 months ago) by root
Content type:	text/plain
Branch:	MAIN
CVS Tags:	rel-6_2, rel-6_3, rel-6_0, rel-5_9, rel-6_1
Changes since 1.29:	+5 -6 lines
Log Message:	* empty log message *
#	Content
1	/*
2	iom.C -- generic I/O multiplexer
3	Copyright (C) 2003, 2004 Marc Lehmann <gvpe@schmorp.de>
4
5	This file is part of GVPE.
6
7	GVPE is free software; you can redistribute it and/or modify
8	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	along with gvpe; if not, write to the Free Software
19	Foundation, Inc. 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20	*/
21
22	#include "iom.h"
23
24	#include <cstdio>
25	#include <cstdlib>
26	#include <cerrno>
27
28	#include <sys/time.h>
29
30	#include <assert.h>
31
32	#if 1 // older unices need these includes for select (2)
33	# include <unistd.h>
34	# include <sys/types.h>
35	# include <time.h>
36	#endif
37
38	// for IOM_SIG
39	#if IOM_SIG
40	# include <csignal>
41	# include <fcntl.h>
42	#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	#include <sys/select.h>
47
48	#define TIMEVAL timeval
49	#define TV_FRAC tv_usec
50	#define TV_MULT 1000000L
51
52	#if IOM_IO
53	static io_manager_vec<io_watcher> iow;
54	#endif
55	#if IOM_CHECK
56	static io_manager_vec<check_watcher> cw;
57	#endif
58	#if IOM_TIME
59	static io_manager_vec<time_watcher> tw;
60	#endif
61	#if IOM_IDLE
62	static io_manager_vec<idle_watcher> iw;
63	#endif
64	#if IOM_SIG
65	static int sigpipe[2]; // signal signalling pipe
66	static sigset_t sigs;
67	struct sig_vec : io_manager_vec<sig_watcher> {
68	int pending;
69	sig_vec ()
70	: pending (false)
71	{ }
72	};
73	static vector<sig_vec *> sw;
74	#endif
75
76	// this is a dummy time watcher to ensure that the first
77	// time watcher is _always_ valid, this gets rid of a lot
78	// of null-pointer-checks
79	// (must come _before_ iom is being defined)
80	static struct tw0 : time_watcher
81	{
82	void cb (time_watcher &w)
83	{
84	// should never get called
85	// reached end-of-time, or tstamp has a bogus definition,
86	// or compiler initialisation order broken, or something else :)
87	abort ();
88	}
89
90	tw0 ()
91	: time_watcher (this, &tw0::cb)
92	{ }
93	} tw0;
94
95	tstamp NOW;
96
97	#if IOM_TIME
98	tstamp io_manager::now ()
99	{
100	struct timeval tv;
101
102	gettimeofday (&tv, 0);
103	return (tstamp)tv.tv_sec + (tstamp)tv.tv_usec / 1000000.;
104	}
105
106	void io_manager::set_now ()
107	{
108	NOW = now ();
109	}
110	#endif
111
112	static bool iom_valid;
113
114	// used for initialisation only
115	static struct init {
116	init ()
117	{
118	#if IOM_SIG
119	sigemptyset (&sigs);
120
121	if (pipe (sigpipe))
122	{
123	perror ("io_manager: unable to create signal pipe, aborting.");
124	abort ();
125	}
126
127	fcntl (sigpipe[0], F_SETFL, O_NONBLOCK); fcntl (sigpipe[0], F_SETFD, FD_CLOEXEC);
128	fcntl (sigpipe[1], F_SETFL, O_NONBLOCK); fcntl (sigpipe[1], F_SETFD, FD_CLOEXEC);
129	#endif
130
131	iom_valid = true;
132
133	#if IOM_TIME
134	io_manager::set_now ();
135
136	tw0.start (TSTAMP_MAX);
137	#endif
138	}
139
140	static void required ();
141	} init;
142
143	void
144	init::required ()
145	{
146	if (!iom_valid)
147	{
148	write (2, "io_manager: early registration attempt, aborting.\n",
149	sizeof ("io_manager: early registration attempt, aborting.\n") - 1);
150	abort ();
151	}
152	}
153
154	template<class watcher>
155	void io_manager::reg (watcher &w, io_manager_vec<watcher> &queue)
156	{
157	init::required ();
158
159	if (!w.active)
160	{
161	queue.push_back (&w);
162	w.active = queue.size ();
163	}
164	}
165
166	template<class watcher>
167	void io_manager::unreg (watcher &w, io_manager_vec<watcher> &queue)
168	{
169	if (!iom_valid)
170	return;
171
172	if (w.active)
173	{
174	queue [w.active - 1] = 0;
175	w.active = 0;
176	}
177	}
178
179	#if IOM_TIME
180	void time_watcher::trigger ()
181	{
182	call (*this);
183	io_manager::reg (*this);
184	}
185
186	void io_manager::reg (time_watcher &w) { io_manager::reg (w, tw); }
187	void io_manager::unreg (time_watcher &w) { io_manager::unreg (w, tw); }
188	#endif
189
190	#if IOM_IO
191	void io_manager::reg (io_watcher &w) { io_manager::reg (w, iow); }
192	void io_manager::unreg (io_watcher &w) { io_manager::unreg (w, iow); }
193	#endif
194
195	#if IOM_CHECK
196	void io_manager::reg (check_watcher &w) { io_manager::reg (w, cw); }
197	void io_manager::unreg (check_watcher &w) { io_manager::unreg (w, cw); }
198	#endif
199
200	#if IOM_IDLE
201	void io_manager::reg (idle_watcher &w) { io_manager::reg (w, iw); }
202	void io_manager::unreg (idle_watcher &w) { io_manager::unreg (w, iw); }
203	#endif
204
205	#if IOM_SIG
206	static void
207	sighandler (int signum)
208	{
209	sw [signum - 1]->pending = true;
210
211	// we use a pipe for signal notifications, as most current
212	// OSes (Linux...) do not implement pselect correctly. ugh.
213	char ch = signum; // actual content not used
214	write (sigpipe[1], &ch, 1);
215	}
216
217	void io_manager::reg (sig_watcher &w)
218	{
219	assert (0 < w.signum);
220
221	sw.reserve (w.signum);
222
223	while (sw.size () < w.signum) // pathetic
224	sw.push_back (0);
225
226	sig_vec *&sv = sw[w.signum - 1];
227
228	if (!sv)
229	{
230	sv = new sig_vec;
231
232	sigaddset (&sigs, w.signum);
233	sigprocmask (SIG_BLOCK, &sigs, NULL);
234
235	struct sigaction sa;
236	sa.sa_handler = sighandler;
237	sigfillset (&sa.sa_mask);
238	sa.sa_flags = SA_RESTART;
239
240	if (sigaction (w.signum, &sa, 0))
241	{
242	perror ("io_manager: error while installing signal handler, ignoring.");
243	abort ();
244	}
245
246	}
247
248	io_manager::reg (w, *sv);
249	}
250
251	void io_manager::unreg (sig_watcher &w)
252	{
253	if (!w.active)
254	return;
255
256	assert (0 < w.signum && w.signum <= sw.size ());
257
258	io_manager::unreg (w, *sw[w.signum - 1]);
259	}
260
261	void sig_watcher::start (int signum)
262	{
263	stop ();
264	this->signum = signum;
265	io_manager::reg (*this);
266	}
267	#endif
268
269	void io_manager::loop ()
270	{
271	init::required ();
272
273	#if IOM_TIME
274	set_now ();
275	#endif
276
277	for (;;)
278	{
279
280	#if IOM_TIME
281	// call pending time watchers
282	{
283	bool activity;
284
285	do
286	{
287	activity = false;
288
289	for (int i = tw.size (); i--; )
290	if (!tw[i])
291	tw.erase_unordered (i);
292	else if (tw[i]->at <= NOW)
293	{
294	time_watcher &w = *tw[i];
295
296	unreg (w);
297	w.call (w);
298
299	activity = true;
300	}
301	}
302	while (activity);
303	}
304	#endif
305
306	#if IOM_CHECK
307	// call all check watchers
308	for (int i = cw.size (); i--; )
309	if (!cw[i])
310	cw.erase_unordered (i);
311	else
312	cw[i]->call (*cw[i]);
313	#endif
314
315	struct TIMEVAL *to = 0;
316	struct TIMEVAL tval;
317
318	#if IOM_IDLE
319	if (iw.size ())
320	{
321	tval.tv_sec = 0;
322	tval.TV_FRAC = 0;
323	to = &tval;
324	}
325	else
326	#endif
327	{
328	#if IOM_TIME
329	// find earliest active watcher
330	time_watcher *next = tw[0]; // the first time-watcher must exist at ALL times
331
332	for (io_manager_vec<time_watcher>::const_iterator i = tw.end (); i-- > tw.begin (); )
333	if (i && (i)->at < next->at)
334	next = *i;
335
336	if (next->at > NOW && next != tw[0])
337	{
338	double diff = next->at - NOW;
339	tval.tv_sec = (int)diff;
340	tval.TV_FRAC = (int) ((diff - tval.tv_sec) * TV_MULT);
341	to = &tval;
342	}
343	}
344	#endif
345
346	#if IOM_IO \|\| IOM_SIG
347	fd_set rfd, wfd;
348
349	FD_ZERO (&rfd);
350	FD_ZERO (&wfd);
351
352	int fds = 0;
353
354	# if IOM_IO
355	for (io_manager_vec<io_watcher>::const_iterator i = iow.end (); i-- > iow.begin (); )
356	if (*i)
357	{
358	if ((i)->events & EVENT_READ ) FD_SET ((i)->fd, &rfd);
359	if ((i)->events & EVENT_WRITE) FD_SET ((i)->fd, &wfd);
360
361	if ((i)->fd >= fds) fds = (i)->fd + 1;
362	}
363	# endif
364
365	if (!to && !fds) //TODO: also check idle_watchers and check_watchers?
366	break; // no events
367
368	# if IOM_SIG
369	FD_SET (sigpipe[0], &rfd);
370	if (sigpipe[0] >= fds) fds = sigpipe[0] + 1;
371	# endif
372
373	# if IOM_SIG
374	// there is no race, as we use a pipe for signals, so select
375	// will return if a signal is caught.
376	sigprocmask (SIG_UNBLOCK, &sigs, NULL);
377	# endif
378	fds = select (fds, &rfd, &wfd, NULL, to);
379	# if IOM_SIG
380	sigprocmask (SIG_BLOCK, &sigs, NULL);
381	# endif
382
383	# if IOM_TIME
384	{
385	// update time, try to compensate for gross non-monotonic time changes
386	tstamp diff = NOW;
387	set_now ();
388	diff = NOW - diff;
389
390	if (diff < 0)
391	for (io_manager_vec<time_watcher>::const_iterator i = tw.end (); i-- > tw.begin (); )
392	if (*i)
393	(*i)->at += diff;
394	}
395	# endif
396
397	if (fds > 0)
398	{
399	# if IOM_SIG
400	if (FD_ISSET (sigpipe[0], &rfd))
401	{
402	char ch;
403
404	while (read (sigpipe[0], &ch, 1) > 0)
405	;
406
407	for (vector<sig_vec *>::iterator svp = sw.end (); svp-- > sw.begin (); )
408	if (svp && (svp)->pending)
409	{
410	sig_vec &sv = **svp;
411	for (int i = sv.size (); i--; )
412	if (!sv[i])
413	sv.erase_unordered (i);
414	else
415	sv[i]->call (*sv[i]);
416
417	sv.pending = false;
418	}
419	}
420	# endif
421
422	# if IOM_IO
423	for (int i = iow.size (); i--; )
424	if (!iow[i])
425	iow.erase_unordered (i);
426	else
427	{
428	io_watcher &w = *iow[i];
429	short revents = w.events;
430
431	if (!FD_ISSET (w.fd, &rfd)) revents &= ~EVENT_READ;
432	if (!FD_ISSET (w.fd, &wfd)) revents &= ~EVENT_WRITE;
433
434	if (revents)
435	w.call (w, revents);
436	}
437	#endif
438	}
439	else if (fds < 0 && errno != EINTR)
440	{
441	perror ("io_manager: fatal error while waiting for I/O or time event, aborting.");
442	abort ();
443	}
444	#if IOM_IDLE
445	else
446	for (int i = iw.size (); i--; )
447	if (!iw[i])
448	iw.erase_unordered (i);
449	else
450	iw[i]->call (*iw[i]);
451	#endif
452
453	#elif IOM_TIME
454	if (!to)
455	break;
456
457	select (0, 0, 0, 0, &to);
458	set_now ();
459	#else
460	break;
461	#endif
462	}
463	}
464