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Comparing gvpe/src/iom.C (file contents):
Revision 1.7 by pcg, Fri Mar 28 05:40:54 2003 UTC vs.
Revision 1.32 by pcg, Tue Apr 26 00:55:56 2005 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 at = when; 100 struct timeval tv;
41 101
42 if (registered) 102 gettimeofday (&tv, 0);
43 iom.reschedule_time_watchers (); 103 return (tstamp)tv.tv_sec + (tstamp)tv.tv_usec / 1000000.;
44 else
45 iom.reg (this);
46} 104}
47 105
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 static void required ();
141} init;
142
143void
144init::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
154template<class watcher>
155void 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
166template<class watcher>
167void 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
48void time_watcher::trigger () 180void time_watcher::trigger ()
49{ 181{
50 call (at); 182 call (*this);
51 183 io_manager::reg (*this);
52 if (registered)
53 iom.reschedule_time_watchers ();
54 else
55 iom.reg (this);
56} 184}
57 185
58void time_watcher::start () 186void io_manager::reg (time_watcher &w) { io_manager::reg (w, tw); }
59{ 187void io_manager::unreg (time_watcher &w) { io_manager::unreg (w, tw); }
60 if (!registered) 188#endif
61 iom.reg (this);
62}
63 189
64void io_manager::reg (int fd, short events, io_watcher *w) 190#if IOM_IO
65{ 191void io_manager::reg (io_watcher &w) { io_manager::reg (w, iow); }
66 pollfd pfd; 192void io_manager::unreg (io_watcher &w) { io_manager::unreg (w, iow); }
193#endif
67 194
68 pfd.fd = fd; 195#if IOM_CHECK
69 pfd.events = events; 196void io_manager::reg (check_watcher &w) { io_manager::reg (w, cw); }
197void io_manager::unreg (check_watcher &w) { io_manager::unreg (w, cw); }
198#endif
70 199
71 pfs.push_back (pfd); 200#if IOM_IDLE
72 iow.push_back (w); 201void io_manager::reg (idle_watcher &w) { io_manager::reg (w, iw); }
73} 202void io_manager::unreg (idle_watcher &w) { io_manager::unreg (w, iw); }
203#endif
74 204
205#if IOM_SIG
206static void
207sighandler (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
75void io_manager::unreg (io_watcher *w) 217void io_manager::reg (sig_watcher &w)
76{ 218{
77 unsigned int sz = iow.size (); 219 assert (0 < w.signum);
78 unsigned int i = find (iow.begin (), iow.end (), w) - iow.begin ();
79 220
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
80 if (i != sz) 228 if (!sv)
81 { 229 {
82 if (sz == 1) 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))
83 { 241 {
242 perror ("io_manager: error while installing signal handler, ignoring.");
84 pfs.clear (); 243 abort ();
85 iow.clear ();
86 } 244 }
87 else if (i == sz - 1) 245
246 }
247
248 io_manager::reg (w, *sv);
249}
250
251void 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
261void sig_watcher::start (int signum)
262{
263 stop ();
264 this->signum = signum;
265 io_manager::reg (*this);
266}
267#endif
268
269void 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 ())
88 { 320 {
89 iow.pop_back (); 321 tval.tv_sec = 0;
90 pfs.pop_back (); 322 tval.TV_FRAC = 0;
323 to = &tval;
91 } 324 }
92 else 325 else
326#endif
93 { 327 {
94 iow[i] = iow[sz - 1]; iow.pop_back (); 328#if IOM_TIME
95 pfs[i] = pfs[sz - 1]; pfs.pop_back (); 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 }
96 } 343 }
97 } 344#endif
98}
99 345
100void io_manager::reschedule_time_watchers () 346#if IOM_IO || IOM_SIG
101{ 347 fd_set rfd, wfd;
102 make_heap (tw.begin (), tw.end (), lowest_first);
103}
104 348
105void io_manager::reg (time_watcher *w) 349 FD_ZERO (&rfd);
106{ 350 FD_ZERO (&wfd);
107 if (w->registered)
108 slog (L_CRIT, "FATAL: io_manager::reg(time_watcher) called on already-registered watcher");
109 351
110 w->registered = true; 352 int fds = 0;
111 353
112 tw.push_back (w); 354# if IOM_IO
113 push_heap (tw.begin (), tw.end (), lowest_first); 355 for (io_manager_vec<io_watcher>::const_iterator i = iow.end (); i-- > iow.begin (); )
114} 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);
115 360
116void io_manager::unreg (time_watcher *w) 361 if ((*i)->fd >= fds) fds = (*i)->fd + 1;
117{ 362 }
118 if (w->registered) 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
119 { 384 {
120 unsigned int sz = tw.size (); 385 // update time, try to compensate for gross non-monotonic time changes
121 unsigned int i = find (tw.begin (), tw.end (), w) - tw.begin (); 386 tstamp diff = NOW;
387 set_now ();
388 diff = NOW - diff;
122 389
123 if (i != sz) 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)
124 { 398 {
125 if (i != sz - 1) 399# if IOM_SIG
126 tw[i] = tw[sz - 1]; 400 if (FD_ISSET (sigpipe[0], &rfd))
401 {
402 char ch;
127 403
128 tw.pop_back (); 404 while (read (sigpipe[0], &ch, 1) > 0)
129 reschedule_time_watchers (); 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
130 } 438 }
131 439 else if (fds < 0 && errno != EINTR)
132 w->registered = false;
133 }
134}
135
136inline void set_now (void)
137{
138 struct timeval tv;
139
140 gettimeofday (&tv, 0);
141
142 NOW = (tstamp)tv.tv_sec + (tstamp)tv.tv_usec / 1000000;
143}
144
145void io_manager::loop ()
146{
147 set_now ();
148
149 for (;;)
150 {
151 while (tw[0]->at <= NOW)
152 { 440 {
153 // remove the first watcher 441 perror ("io_manager: fatal error while waiting for I/O or time event, aborting.");
154 time_watcher *w = tw[0];
155
156 pop_heap (tw.begin (), tw.end (), lowest_first);
157 tw.pop_back ();
158
159 w->registered = false;
160
161 // call it
162 w->call (w->at);
163
164 // re-add it if necessary
165 if (w->at >= 0 && !w->registered)
166 reg (w); 442 abort ();
167 } 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
168 452
169 int timeout = (int) ((tw[0]->at - NOW) * 1000); 453#elif IOM_TIME
454 if (!to)
455 break;
170 456
171 int fds = poll (&pfs[0], pfs.size (), timeout); 457 select (0, 0, 0, 0, &to);
172
173 set_now (); 458 set_now ();
174 459#else
175 for (unsigned int i = iow.size (); fds > 0 && i--; ) 460 break;
176 if (pfs[i].revents) 461#endif
177 {
178 --fds;
179 iow[i]->call (pfs[i].revents);
180 }
181 } 462 }
182} 463}
183 464
184void io_manager::idle_cb (tstamp &ts)
185{
186 ts = NOW + 86400; // wake up every day, for no good reason
187}
188
189io_manager::io_manager ()
190{
191 set_now ();
192 idle = new time_watcher (this, &io_manager::idle_cb);
193 idle->start (0);
194}
195
196io_manager::~io_manager ()
197{
198 //
199}
200

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