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Comparing gvpe/src/iom.C (file contents):
Revision 1.4 by pcg, Fri Mar 21 23:17:01 2003 UTC vs.
Revision 1.33 by pcg, Wed Jan 11 21:27:05 2006 UTC

1/* 1/*
2 iom.C -- I/O multiplexor 2 iom.C -- generic I/O multiplexer
3 Copyright (C) 2003, 2004 Marc Lehmann <gvpe@schmorp.de>
3 4
5 This file is part of GVPE.
6
4 This program is free software; you can redistribute it and/or modify 7 GVPE is free software; you can redistribute it and/or modify
5 it under the terms of the GNU General Public License as published by 8 it under the terms of the GNU General Public License as published by
6 the Free Software Foundation; either version 2 of the License, or 9 the Free Software Foundation; either version 2 of the License, or
7 (at your option) any later version. 10 (at your option) any later version.
8 11
9 This program is distributed in the hope that it will be useful, 12 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of 13 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU General Public License for more details. 15 GNU General Public License for more details.
13 16
14 You should have received a copy of the GNU General Public License 17 You should have received a copy of the GNU General Public License
15 along with this program; if not, write to the Free Software 18 along with gvpe; if not, write to the Free Software
16 Foundation, Inc. 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 19 Foundation, Inc. 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
17*/ 20*/
18 21
19#include "config.h" 22#include "iom.h"
23
24#include <cstdio>
25#include <cstdlib>
26#include <cerrno>
20 27
21#include <sys/time.h> 28#include <sys/time.h>
22 29
23#include <algorithm> 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
24#include <functional> 40# include <csignal>
41# include <fcntl.h>
42#endif
25 43
26#include "slog.h" 44// if the BSDs would at least be marginally POSIX-compatible.. *sigh*
27#include "iom.h" 45// until that happens, sys/select.h must come last
46#include <sys/select.h>
28 47
29inline bool lowest_first (const time_watcher *a, const time_watcher *b) 48#define TIMEVAL timeval
30{ 49#define TV_FRAC tv_usec
31 return a->at > b->at; 50#define TV_MULT 1000000L
32} 51
52#if IOM_IO
53static io_manager_vec<io_watcher> iow;
54#endif
55#if IOM_CHECK
56static io_manager_vec<check_watcher> cw;
57#endif
58#if IOM_TIME
59static io_manager_vec<time_watcher> tw;
60#endif
61#if IOM_IDLE
62static io_manager_vec<idle_watcher> iw;
63#endif
64#if IOM_SIG
65static int sigpipe[2]; // signal signalling pipe
66static sigset_t sigs;
67struct sig_vec : io_manager_vec<sig_watcher> {
68 int pending;
69 sig_vec ()
70 : pending (false)
71 { }
72};
73static 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)
80static 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;
33 94
34tstamp NOW; 95tstamp NOW;
35 96
36io_manager iom; 97#if IOM_TIME
37 98tstamp io_manager::now ()
38void time_watcher::set (tstamp when)
39{ 99{
40 iom.unreg (this); 100 struct timeval tv;
41 at = when;
42 iom.reg (this);
43}
44 101
102 gettimeofday (&tv, 0);
103 return (tstamp)tv.tv_sec + (tstamp)tv.tv_usec / 1000000.;
104}
105
106void io_manager::set_now ()
107{
108 NOW = now ();
109}
110#endif
111
112static bool iom_valid;
113
114// used for initialisation only
115static 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 ~init ()
141 {
142 iom_valid = false;
143 }
144
145 static void required ();
146} init;
147
148void
149init::required ()
150{
151 if (!iom_valid)
152 {
153 write (2, "io_manager: early registration attempt, aborting.\n",
154 sizeof ("io_manager: early registration attempt, aborting.\n") - 1);
155 abort ();
156 }
157}
158
159template<class watcher>
160void io_manager::reg (watcher &w, io_manager_vec<watcher> &queue)
161{
162 init::required ();
163
164 if (!w.active)
165 {
166 queue.push_back (&w);
167 w.active = queue.size ();
168 }
169}
170
171template<class watcher>
172void io_manager::unreg (watcher &w, io_manager_vec<watcher> &queue)
173{
174 if (!iom_valid)
175 return;
176
177 if (w.active)
178 {
179 queue [w.active - 1] = 0;
180 w.active = 0;
181 }
182}
183
184#if IOM_TIME
45void time_watcher::trigger () 185void time_watcher::trigger ()
46{ 186{
47 iom.unreg (this);
48 call (at); 187 call (*this);
49 iom.reg (this);
50}
51
52void time_watcher::start ()
53{
54 iom.unreg (this); 188 io_manager::reg (*this);
55 iom.reg (this);
56} 189}
57 190
58void io_manager::reg (int fd, short events, io_watcher *w) 191void io_manager::reg (time_watcher &w) { io_manager::reg (w, tw); }
59{ 192void io_manager::unreg (time_watcher &w) { io_manager::unreg (w, tw); }
60 pollfd pfd; 193#endif
61 194
62 pfd.fd = fd; 195#if IOM_IO
63 pfd.events = events; 196void io_manager::reg (io_watcher &w) { io_manager::reg (w, iow); }
197void io_manager::unreg (io_watcher &w) { io_manager::unreg (w, iow); }
198#endif
64 199
65 pfs.push_back (pfd); 200#if IOM_CHECK
66 iow.push_back (w); 201void io_manager::reg (check_watcher &w) { io_manager::reg (w, cw); }
67} 202void io_manager::unreg (check_watcher &w) { io_manager::unreg (w, cw); }
203#endif
68 204
205#if IOM_IDLE
206void io_manager::reg (idle_watcher &w) { io_manager::reg (w, iw); }
207void io_manager::unreg (idle_watcher &w) { io_manager::unreg (w, iw); }
208#endif
209
210#if IOM_SIG
211static void
212sighandler (int signum)
213{
214 sw [signum - 1]->pending = true;
215
216 // we use a pipe for signal notifications, as most current
217 // OSes (Linux...) do not implement pselect correctly. ugh.
218 char ch = signum; // actual content not used
219 write (sigpipe[1], &ch, 1);
220}
221
69void io_manager::unreg (io_watcher *w) 222void io_manager::reg (sig_watcher &w)
70{ 223{
71 unsigned int sz = iow.size (); 224 init::required ();
72 unsigned int i = find (iow.begin (), iow.end (), w) - iow.begin ();
73 225
226 assert (0 < w.signum);
227
228 sw.reserve (w.signum);
229
230 while (sw.size () < w.signum) // pathetic
231 sw.push_back (0);
232
233 sig_vec *&sv = sw[w.signum - 1];
234
74 if (i != sz) 235 if (!sv)
75 { 236 {
76 if (sz == 1) 237 sv = new sig_vec;
238
239 sigaddset (&sigs, w.signum);
240 sigprocmask (SIG_BLOCK, &sigs, NULL);
241
242 struct sigaction sa;
243 sa.sa_handler = sighandler;
244 sigfillset (&sa.sa_mask);
245 sa.sa_flags = SA_RESTART;
246
247 if (sigaction (w.signum, &sa, 0))
77 { 248 {
249 perror ("io_manager: error while installing signal handler, ignoring.");
78 pfs.clear (); 250 abort ();
79 iow.clear ();
80 } 251 }
81 else if (i == sz - 1) 252
253 }
254
255 io_manager::reg (w, *sv);
256}
257
258void io_manager::unreg (sig_watcher &w)
259{
260 if (!w.active || !iom_valid)
261 return;
262
263 assert (0 < w.signum && w.signum <= sw.size ());
264
265 io_manager::unreg (w, *sw[w.signum - 1]);
266}
267
268void sig_watcher::start (int signum)
269{
270 stop ();
271 this->signum = signum;
272 io_manager::reg (*this);
273}
274#endif
275
276void io_manager::loop ()
277{
278 init::required ();
279
280#if IOM_TIME
281 set_now ();
282#endif
283
284 for (;;)
285 {
286
287#if IOM_TIME
288 // call pending time watchers
289 {
290 bool activity;
291
292 do
293 {
294 activity = false;
295
296 for (int i = tw.size (); i--; )
297 if (!tw[i])
298 tw.erase_unordered (i);
299 else if (tw[i]->at <= NOW)
300 {
301 time_watcher &w = *tw[i];
302
303 unreg (w);
304 w.call (w);
305
306 activity = true;
307 }
308 }
309 while (activity);
310 }
311#endif
312
313#if IOM_CHECK
314 // call all check watchers
315 for (int i = cw.size (); i--; )
316 if (!cw[i])
317 cw.erase_unordered (i);
318 else
319 cw[i]->call (*cw[i]);
320#endif
321
322 struct TIMEVAL *to = 0;
323 struct TIMEVAL tval;
324
325#if IOM_IDLE
326 if (iw.size ())
82 { 327 {
83 iow.pop_back (); 328 tval.tv_sec = 0;
84 pfs.pop_back (); 329 tval.TV_FRAC = 0;
330 to = &tval;
85 } 331 }
86 else 332 else
333#endif
87 { 334 {
88 iow[i] = iow[sz - 1]; iow.pop_back (); 335#if IOM_TIME
89 pfs[i] = pfs[sz - 1]; pfs.pop_back (); 336 // find earliest active watcher
337 time_watcher *next = tw[0]; // the first time-watcher must exist at ALL times
338
339 for (io_manager_vec<time_watcher>::const_iterator i = tw.end (); i-- > tw.begin (); )
340 if (*i && (*i)->at < next->at)
341 next = *i;
342
343 if (next->at > NOW && next != tw[0])
344 {
345 double diff = next->at - NOW;
346 tval.tv_sec = (int)diff;
347 tval.TV_FRAC = (int) ((diff - tval.tv_sec) * TV_MULT);
348 to = &tval;
349 }
90 } 350 }
91 } 351#endif
92}
93 352
94void io_manager::reg (time_watcher *w) 353#if IOM_IO || IOM_SIG
95{ 354 fd_set rfd, wfd;
96 tw.push_back (w);
97 push_heap (tw.begin (), tw.end (), lowest_first);
98}
99 355
100void io_manager::unreg (time_watcher *w) 356 FD_ZERO (&rfd);
101{ 357 FD_ZERO (&wfd);
102 unsigned int sz = tw.size ();
103 unsigned int i = find (tw.begin (), tw.end (), w) - tw.begin ();
104 358
105 if (i != sz) 359 int fds = 0;
360
361# if IOM_IO
362 for (io_manager_vec<io_watcher>::const_iterator i = iow.end (); i-- > iow.begin (); )
363 if (*i)
364 {
365 if ((*i)->events & EVENT_READ ) FD_SET ((*i)->fd, &rfd);
366 if ((*i)->events & EVENT_WRITE) FD_SET ((*i)->fd, &wfd);
367
368 if ((*i)->fd >= fds) fds = (*i)->fd + 1;
369 }
370# endif
371
372 if (!to && !fds) //TODO: also check idle_watchers and check_watchers?
373 break; // no events
374
375# if IOM_SIG
376 FD_SET (sigpipe[0], &rfd);
377 if (sigpipe[0] >= fds) fds = sigpipe[0] + 1;
378# endif
379
380# if IOM_SIG
381 // there is no race, as we use a pipe for signals, so select
382 // will return if a signal is caught.
383 sigprocmask (SIG_UNBLOCK, &sigs, NULL);
384# endif
385 fds = select (fds, &rfd, &wfd, NULL, to);
386# if IOM_SIG
387 sigprocmask (SIG_BLOCK, &sigs, NULL);
388# endif
389
390# if IOM_TIME
106 { 391 {
107 if (i != sz - 1) 392 // update time, try to compensate for gross non-monotonic time changes
108 tw[i] = tw[sz - 1]; 393 tstamp diff = NOW;
394 set_now ();
395 diff = NOW - diff;
109 396
110 tw.pop_back (); 397 if (diff < 0)
111 make_heap (tw.begin (), tw.end (), lowest_first); 398 for (io_manager_vec<time_watcher>::const_iterator i = tw.end (); i-- > tw.begin (); )
399 if (*i)
400 (*i)->at += diff;
112 } 401 }
113} 402# endif
114 403
115inline void set_now (void) 404 if (fds > 0)
116{
117 struct timeval tv;
118
119 gettimeofday (&tv, 0);
120
121 NOW = (tstamp)tv.tv_sec + (tstamp)tv.tv_usec / 1000000;
122}
123
124void io_manager::loop ()
125{
126 set_now ();
127
128 for (;;)
129 {
130 while (tw[0]->at <= NOW)
131 { 405 {
132 pop_heap (tw.begin (), tw.end (), lowest_first); 406# if IOM_SIG
133 time_watcher *w = *(tw.end () - 1); 407 if (FD_ISSET (sigpipe[0], &rfd))
134
135 if (w->at >= 0)
136 { 408 {
137 w->call (w->at); 409 char ch;
138 push_heap (tw.begin (), tw.end (), lowest_first); 410
411 while (read (sigpipe[0], &ch, 1) > 0)
412 ;
413
414 for (vector<sig_vec *>::iterator svp = sw.end (); svp-- > sw.begin (); )
415 if (*svp && (*svp)->pending)
416 {
417 sig_vec &sv = **svp;
418 for (int i = sv.size (); i--; )
419 if (!sv[i])
420 sv.erase_unordered (i);
421 else
422 sv[i]->call (*sv[i]);
423
424 sv.pending = false;
425 }
139 } 426 }
427# endif
428
429# if IOM_IO
430 for (int i = iow.size (); i--; )
431 if (!iow[i])
432 iow.erase_unordered (i);
433 else
434 {
435 io_watcher &w = *iow[i];
436 short revents = w.events;
437
438 if (!FD_ISSET (w.fd, &rfd)) revents &= ~EVENT_READ;
439 if (!FD_ISSET (w.fd, &wfd)) revents &= ~EVENT_WRITE;
440
441 if (revents)
442 w.call (w, revents);
443 }
444#endif
445 }
446 else if (fds < 0 && errno != EINTR)
447 {
448 perror ("io_manager: fatal error while waiting for I/O or time event, aborting.");
449 abort ();
450 }
451#if IOM_IDLE
452 else
453 for (int i = iw.size (); i--; )
454 if (!iw[i])
455 iw.erase_unordered (i);
140 else 456 else
141 tw.pop_back (); 457 iw[i]->call (*iw[i]);
142 } 458#endif
143 459
144 int timeout = (int) ((tw[0]->at - NOW) * 1000); 460#elif IOM_TIME
461 if (!to)
462 break;
145 463
146 int fds = poll (&pfs[0], pfs.size (), timeout); 464 select (0, 0, 0, 0, &to);
147
148 set_now (); 465 set_now ();
149 466#else
150 for (unsigned int i = iow.size (); fds > 0 && i--; ) 467 break;
151 if (pfs[i].revents) 468#endif
152 {
153 --fds;
154 iow[i]->call (pfs[i].revents);
155 }
156 } 469 }
157} 470}
158 471
159void io_manager::idle_cb (tstamp &ts)
160{
161 ts = NOW + 86400; // wake up every day, for no good reason
162}
163
164io_manager::io_manager ()
165{
166 set_now ();
167 idle = new time_watcher (this, &io_manager::idle_cb);
168 idle->start (0);
169}
170
171io_manager::~io_manager ()
172{
173 //
174}
175

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