rxvt-unicode/src/iom.C

/*
    iom.C -- generic I/O multiplexer
    Copyright (C) 2003, 2004 Marc Lehmann <pcg@goof.com>
 
    This program 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 this program; 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 <signal.h>
# 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
inline void set_now (void)
{
  struct timeval tv;

  gettimeofday (&tv, 0);
  NOW = (tstamp)tv.tv_sec + (tstamp)tv.tv_usec / 1000000.;
}
#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[1], F_SETFL, O_NONBLOCK);
#endif

    iom_valid = true;

#if IOM_TIME
    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
      set_now ();
# 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
              {
                short revents = iow[i]->events;

                if (!FD_ISSET (iow[i]->fd, &rfd)) revents &= ~EVENT_READ;
                if (!FD_ISSET (iow[i]->fd, &wfd)) revents &= ~EVENT_WRITE;

                if (revents)
                  iow[i]->call (*iow[i], 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:	1.23
Committed:	Sun Nov 14 22:24:09 2004 UTC (19 years, 6 months ago) by root
Content type:	text/plain
Branch:	MAIN
CVS Tags:	rel-4_2, rel-4_3, rel-4_1
Changes since 1.19:	+49 -48 lines
Log Message:	* empty log message *
#	Content
1	/*
2	iom.C -- generic I/O multiplexer
3	Copyright (C) 2003, 2004 Marc Lehmann <pcg@goof.com>
4
5	This program is free software; you can redistribute it and/or modify
6	it under the terms of the GNU General Public License as published by
7	the Free Software Foundation; either version 2 of the License, or
8	(at your option) any later version.
9
10	This program is distributed in the hope that it will be useful,
11	but WITHOUT ANY WARRANTY; without even the implied warranty of
12	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13	GNU General Public License for more details.
14
15	You should have received a copy of the GNU General Public License
16	along with this program; if not, write to the Free Software
17	Foundation, Inc. 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18	*/
19
20	#include "iom.h"
21
22	#include <cstdio>
23	#include <cstdlib>
24	#include <cerrno>
25
26	#include <sys/time.h>
27
28	#include <assert.h>
29
30	#if 1 // older unices need these includes for select (2)
31	# include <unistd.h>
32	# include <sys/types.h>
33	# include <time.h>
34	#endif
35
36	// for IOM_SIG
37	#if IOM_SIG
38	# include <signal.h>
39	# include <fcntl.h>
40	#endif
41
42	// if the BSDs would at least be marginally POSIX-compatible.. sigh
43	// until that happens, sys/select.h must come last
44	#include <sys/select.h>
45
46	// TSTAMP_MAX must still fit into a positive struct timeval
47	#define TSTAMP_MAX (double)(1UL<<31)
48
49	#define TIMEVAL timeval
50	#define TV_FRAC tv_usec
51	#define TV_MULT 1000000L
52
53	#if IOM_IO
54	static io_manager_vec<io_watcher> iow;
55	#endif
56	#if IOM_CHECK
57	static io_manager_vec<check_watcher> cw;
58	#endif
59	#if IOM_TIME
60	static io_manager_vec<time_watcher> tw;
61	#endif
62	#if IOM_IDLE
63	static io_manager_vec<idle_watcher> iw;
64	#endif
65	#if IOM_SIG
66	static int sigpipe[2]; // signal signalling pipe
67	static sigset_t sigs;
68	struct sig_vec : io_manager_vec<sig_watcher> {
69	int pending;
70	sig_vec ()
71	: pending (false)
72	{ }
73	};
74	static vector<sig_vec *> sw;
75	#endif
76
77	// this is a dummy time watcher to ensure that the first
78	// time watcher is _always_ valid, this gets rid of a lot
79	// of null-pointer-checks
80	// (must come _before_ iom is being defined)
81	static struct tw0 : time_watcher
82	{
83	void cb (time_watcher &w)
84	{
85	// should never get called
86	// reached end-of-time, or tstamp has a bogus definition,
87	// or compiler initialisation order broken, or something else :)
88	abort ();
89	}
90
91	tw0 ()
92	: time_watcher (this, &tw0::cb)
93	{ }
94	} tw0;
95
96	tstamp NOW;
97
98	#if IOM_TIME
99	inline void set_now (void)
100	{
101	struct timeval tv;
102
103	gettimeofday (&tv, 0);
104	NOW = (tstamp)tv.tv_sec + (tstamp)tv.tv_usec / 1000000.;
105	}
106	#endif
107
108	static bool iom_valid;
109
110	// used for initialisation only
111	static struct init {
112	init ()
113	{
114	#if IOM_SIG
115	sigemptyset (&sigs);
116
117	if (pipe (sigpipe))
118	{
119	perror ("io_manager: unable to create signal pipe, aborting.");
120	abort ();
121	}
122
123	fcntl (sigpipe[0], F_SETFL, O_NONBLOCK);
124	fcntl (sigpipe[1], F_SETFL, O_NONBLOCK);
125	#endif
126
127	iom_valid = true;
128
129	#if IOM_TIME
130	set_now ();
131
132	tw0.start (TSTAMP_MAX);
133	#endif
134	}
135
136	static void required ();
137	} init;
138
139	void
140	init::required ()
141	{
142	if (!iom_valid)
143	{
144	write (2, "io_manager: early registration attempt, aborting.\n",
145	sizeof ("io_manager: early registration attempt, aborting.\n") - 1);
146	abort ();
147	}
148	}
149
150	template<class watcher>
151	void io_manager::reg (watcher &w, io_manager_vec<watcher> &queue)
152	{
153	init::required ();
154
155	if (!w.active)
156	{
157	queue.push_back (&w);
158	w.active = queue.size ();
159	}
160	}
161
162	template<class watcher>
163	void io_manager::unreg (watcher &w, io_manager_vec<watcher> &queue)
164	{
165	if (!iom_valid)
166	return;
167
168	if (w.active)
169	{
170	queue [w.active - 1] = 0;
171	w.active = 0;
172	}
173	}
174
175	#if IOM_TIME
176	void time_watcher::trigger ()
177	{
178	call (*this);
179	io_manager::reg (*this);
180	}
181
182	void io_manager::reg (time_watcher &w) { io_manager::reg (w, tw); }
183	void io_manager::unreg (time_watcher &w) { io_manager::unreg (w, tw); }
184	#endif
185
186	#if IOM_IO
187	void io_manager::reg (io_watcher &w) { io_manager::reg (w, iow); }
188	void io_manager::unreg (io_watcher &w) { io_manager::unreg (w, iow); }
189	#endif
190
191	#if IOM_CHECK
192	void io_manager::reg (check_watcher &w) { io_manager::reg (w, cw); }
193	void io_manager::unreg (check_watcher &w) { io_manager::unreg (w, cw); }
194	#endif
195
196	#if IOM_IDLE
197	void io_manager::reg (idle_watcher &w) { io_manager::reg (w, iw); }
198	void io_manager::unreg (idle_watcher &w) { io_manager::unreg (w, iw); }
199	#endif
200
201	#if IOM_SIG
202	static void
203	sighandler (int signum)
204	{
205	sw [signum - 1]->pending = true;
206
207	// we use a pipe for signal notifications, as most current
208	// OSes (Linux...) do not implement pselect correctly. ugh.
209	char ch = signum; // actual content not used
210	write (sigpipe[1], &ch, 1);
211	}
212
213	void io_manager::reg (sig_watcher &w)
214	{
215	assert (0 < w.signum);
216
217	sw.reserve (w.signum);
218
219	while (sw.size () < w.signum) // pathetic
220	sw.push_back (0);
221
222	sig_vec *&sv = sw[w.signum - 1];
223
224	if (!sv)
225	{
226	sv = new sig_vec;
227
228	sigaddset (&sigs, w.signum);
229	sigprocmask (SIG_BLOCK, &sigs, NULL);
230
231	struct sigaction sa;
232	sa.sa_handler = sighandler;
233	sigfillset (&sa.sa_mask);
234	sa.sa_flags = SA_RESTART;
235
236	if (sigaction (w.signum, &sa, 0))
237	{
238	perror ("io_manager: error while installing signal handler, ignoring.");
239	abort ();
240	}
241
242	}
243
244	io_manager::reg (w, *sv);
245	}
246
247	void io_manager::unreg (sig_watcher &w)
248	{
249	if (!w.active)
250	return;
251
252	assert (0 < w.signum && w.signum <= sw.size ());
253
254	io_manager::unreg (w, *sw[w.signum - 1]);
255	}
256
257	void sig_watcher::start (int signum)
258	{
259	stop ();
260	this->signum = signum;
261	io_manager::reg (*this);
262	}
263	#endif
264
265	void io_manager::loop ()
266	{
267	init::required ();
268
269	#if IOM_TIME
270	set_now ();
271	#endif
272
273	for (;;)
274	{
275
276	#if IOM_TIME
277	// call pending time watchers
278	{
279	bool activity;
280
281	do
282	{
283	activity = false;
284
285	for (int i = tw.size (); i--; )
286	if (!tw[i])
287	tw.erase_unordered (i);
288	else if (tw[i]->at <= NOW)
289	{
290	time_watcher &w = *tw[i];
291
292	unreg (w);
293	w.call (w);
294
295	activity = true;
296	}
297	}
298	while (activity);
299	}
300	#endif
301
302	#if IOM_CHECK
303	// call all check watchers
304	for (int i = cw.size (); i--; )
305	if (!cw[i])
306	cw.erase_unordered (i);
307	else
308	cw[i]->call (*cw[i]);
309	#endif
310
311	struct TIMEVAL *to = 0;
312	struct TIMEVAL tval;
313
314	#if IOM_IDLE
315	if (iw.size ())
316	{
317	tval.tv_sec = 0;
318	tval.TV_FRAC = 0;
319	to = &tval;
320	}
321	else
322	#endif
323	{
324	#if IOM_TIME
325	// find earliest active watcher
326	time_watcher *next = tw[0]; // the first time-watcher must exist at ALL times
327
328	for (io_manager_vec<time_watcher>::const_iterator i = tw.end (); i-- > tw.begin (); )
329	if (i && (i)->at < next->at)
330	next = *i;
331
332	if (next->at > NOW && next != tw[0])
333	{
334	double diff = next->at - NOW;
335	tval.tv_sec = (int)diff;
336	tval.TV_FRAC = (int) ((diff - tval.tv_sec) * TV_MULT);
337	to = &tval;
338	}
339	}
340	#endif
341
342	#if IOM_IO \|\| IOM_SIG
343	fd_set rfd, wfd;
344
345	FD_ZERO (&rfd);
346	FD_ZERO (&wfd);
347
348	int fds = 0;
349
350	# if IOM_IO
351	for (io_manager_vec<io_watcher>::const_iterator i = iow.end (); i-- > iow.begin (); )
352	if (*i)
353	{
354	if ((i)->events & EVENT_READ ) FD_SET ((i)->fd, &rfd);
355	if ((i)->events & EVENT_WRITE) FD_SET ((i)->fd, &wfd);
356
357	if ((i)->fd >= fds) fds = (i)->fd + 1;
358	}
359	# endif
360
361	if (!to && !fds) //TODO: also check idle_watchers and check_watchers?
362	break; // no events
363
364	# if IOM_SIG
365	FD_SET (sigpipe[0], &rfd);
366	if (sigpipe[0] >= fds) fds = sigpipe[0] + 1;
367	# endif
368
369	# if IOM_SIG
370	// there is no race, as we use a pipe for signals, so select
371	// will return if a signal is caught.
372	sigprocmask (SIG_UNBLOCK, &sigs, NULL);
373	# endif
374	fds = select (fds, &rfd, &wfd, NULL, to);
375	# if IOM_SIG
376	sigprocmask (SIG_BLOCK, &sigs, NULL);
377	# endif
378
379	# if IOM_TIME
380	set_now ();
381	# endif
382
383	if (fds > 0)
384	{
385	# if IOM_SIG
386	if (FD_ISSET (sigpipe[0], &rfd))
387	{
388	char ch;
389
390	while (read (sigpipe[0], &ch, 1) > 0)
391	;
392
393	for (vector<sig_vec *>::iterator svp = sw.end (); svp-- > sw.begin (); )
394	if (svp && (svp)->pending)
395	{
396	sig_vec &sv = **svp;
397	for (int i = sv.size (); i--; )
398	if (!sv[i])
399	sv.erase_unordered (i);
400	else
401	sv[i]->call (*sv[i]);
402
403	sv.pending = false;
404	}
405	}
406	# endif
407
408	# if IOM_IO
409	for (int i = iow.size (); i--; )
410	if (!iow[i])
411	iow.erase_unordered (i);
412	else
413	{
414	short revents = iow[i]->events;
415
416	if (!FD_ISSET (iow[i]->fd, &rfd)) revents &= ~EVENT_READ;
417	if (!FD_ISSET (iow[i]->fd, &wfd)) revents &= ~EVENT_WRITE;
418
419	if (revents)
420	iow[i]->call (*iow[i], revents);
421	}
422	#endif
423	}
424	else if (fds < 0 && errno != EINTR)
425	{
426	perror ("io_manager: fatal error while waiting for I/O or time event, aborting.");
427	abort ();
428	}
429	#if IOM_IDLE
430	else
431	for (int i = iw.size (); i--; )
432	if (!iw[i])
433	iw.erase_unordered (i);
434	else
435	iw[i]->call (*iw[i]);
436	#endif
437
438	#elif IOM_TIME
439	if (!to)
440	break;
441
442	select (0, 0, 0, 0, &to);
443	set_now ();
444	#else
445	break;
446	#endif
447	}
448	}
449