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Comparing gvpe/src/iom.C (file contents):
Revision 1.8 by pcg, Wed Apr 2 05:15:00 2003 UTC vs.
Revision 1.36 by pcg, Thu Dec 14 03:18:53 2006 UTC

1/* 1/*
2 iom.C -- I/O multiplexor 2 iom.C -- generic I/O multiplexer
3 Copyright (C) 2003-2006 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"
20 23
24#include <cstdio>
25#include <cstdlib>
26#include <cerrno>
27#include <cassert>
28
29#include <sys/types.h>
21#include <sys/time.h> 30#include <sys/time.h>
22 31
23#include <algorithm> 32#if 1 // older unices need these includes for select (2)
33# include <unistd.h>
34# include <time.h>
35#endif
36
37#if IOM_CHILD
38# include <sys/wait.h>
39#endif
40
41#if IOM_SIG
24#include <functional> 42# include <csignal>
43# include <fcntl.h>
44#endif
25 45
26#include "slog.h" 46// if the BSDs would at least be marginally POSIX-compatible.. *sigh*
27#include "iom.h" 47// until that happens, sys/select.h must come last
48#include <sys/select.h>
28 49
29inline bool lowest_first (const time_watcher *a, const time_watcher *b) 50#define TIMEVAL timeval
51#define TV_FRAC tv_usec
52#define TV_MULT 1000000L
53
54#if IOM_IO
55static io_manager_vec<io_watcher> iow;
56#endif
57#if IOM_CHECK
58static io_manager_vec<check_watcher> cw;
59#endif
60#if IOM_TIME
61static io_manager_vec<time_watcher> tw;
62#endif
63#if IOM_IDLE
64static io_manager_vec<idle_watcher> iw;
65#endif
66#if IOM_SIG
67static int sigpipe[2]; // signal signalling pipe
68static sigset_t sigs;
69struct sig_vec : io_manager_vec<sig_watcher> {
70 int pending;
71 sig_vec ()
72 : pending (false)
73 { }
74};
75static vector<sig_vec *> sw;
76#endif
77#if IOM_CHILD
78static io_manager_vec<child_watcher> pw;
79#endif
80
81// this is a dummy time watcher to ensure that the first
82// time watcher is _always_ valid, this gets rid of a lot
83// of null-pointer-checks
84// (must come _before_ iom is being defined)
85static struct tw0 : time_watcher
30{ 86{
31 return a->at > b->at; 87 void cb (time_watcher &w)
32} 88 {
89 // should never get called
90 // reached end-of-time, or tstamp has a bogus definition,
91 // or compiler initialisation order broken, or something else :)
92 abort ();
93 }
94
95 tw0 ()
96 : time_watcher (this, &tw0::cb)
97 { }
98} tw0;
33 99
34tstamp NOW; 100tstamp NOW;
35 101
36io_manager iom; 102#if IOM_CHILD
37 103// sig_watcher for child signal(s)
38void time_watcher::set (tstamp when) 104static struct sw0 : sig_watcher
39{ 105{
40 at = when; 106 void cb (sig_watcher &w)
107 {
108 // SIGCHLD, call corresponding watchera
109 pid_t pid;
110 int status;
41 111
42 if (registered) 112 while ((pid = waitpid (-1, &status, WNOHANG)) > 0)
43 iom.reschedule_time_watchers (); 113 for (int i = pw.size (); i--; )
44 else 114 {
45 iom.reg (this); 115 child_watcher *w = pw[i];
46}
47 116
117 if (!w)
118 pw.erase_unordered (i);
119 else if (w->pid == pid)
120 {
121 io_manager::unreg (*w);
122 w->call (*w, status);
123 }
124 }
125 }
126
127 sw0 ()
128 : sig_watcher (this, &sw0::cb)
129 { }
130} sw0;
131#endif
132
133#if IOM_TIME
134tstamp io_manager::now ()
135{
136 struct timeval tv;
137
138 gettimeofday (&tv, 0);
139 return (tstamp)tv.tv_sec + (tstamp)tv.tv_usec / 1000000.;
140}
141
142void io_manager::set_now ()
143{
144 NOW = now ();
145}
146#endif
147
148static bool iom_valid;
149
150// used for initialisation only
151static struct init {
152 init ()
153 {
154 iom_valid = true;
155
156#if IOM_SIG
157 sigemptyset (&sigs);
158
159 if (pipe (sigpipe))
160 {
161 perror ("io_manager: unable to create signal pipe, aborting.");
162 abort ();
163 }
164
165 fcntl (sigpipe[0], F_SETFL, O_NONBLOCK); fcntl (sigpipe[0], F_SETFD, FD_CLOEXEC);
166 fcntl (sigpipe[1], F_SETFL, O_NONBLOCK); fcntl (sigpipe[1], F_SETFD, FD_CLOEXEC);
167#endif
168
169#if IOM_CHILD
170 sw0.start (SIGCHLD);
171#endif
172
173#if IOM_TIME
174 io_manager::set_now ();
175
176 tw0.start (TSTAMP_MAX);
177#endif
178 }
179
180 ~init ()
181 {
182 iom_valid = false;
183 }
184
185 static void required ();
186} init;
187
188void
189init::required ()
190{
191 if (!iom_valid)
192 {
193 write (2, "io_manager: early registration attempt, aborting.\n",
194 sizeof ("io_manager: early registration attempt, aborting.\n") - 1);
195 abort ();
196 }
197}
198
199template<class watcher>
200void io_manager::reg (watcher &w, io_manager_vec<watcher> &queue)
201{
202 init::required ();
203
204 if (!w.active)
205 {
206 queue.push_back (&w);
207 w.active = queue.size ();
208 }
209}
210
211template<class watcher>
212void io_manager::unreg (watcher &w, io_manager_vec<watcher> &queue)
213{
214 if (!iom_valid)
215 return;
216
217 if (w.active)
218 {
219 queue [w.active - 1] = 0;
220 w.active = 0;
221 }
222}
223
224#if IOM_TIME
48void time_watcher::trigger () 225void time_watcher::trigger ()
49{ 226{
50 call (at); 227 call (*this);
51 228 io_manager::reg (*this);
52 if (registered)
53 iom.reschedule_time_watchers ();
54 else
55 iom.reg (this);
56} 229}
57 230
58void time_watcher::start () 231void io_manager::reg (time_watcher &w) { io_manager::reg (w, tw); }
59{ 232void io_manager::unreg (time_watcher &w) { io_manager::unreg (w, tw); }
60 if (!registered) 233#endif
61 iom.reg (this);
62}
63 234
64void io_manager::reg (int fd, short events, io_watcher *w) 235#if IOM_IO
65{ 236void io_manager::reg (io_watcher &w) { io_manager::reg (w, iow); }
66 pollfd pfd; 237void io_manager::unreg (io_watcher &w) { io_manager::unreg (w, iow); }
238#endif
67 239
68 pfd.fd = fd; 240#if IOM_CHECK
69 pfd.events = events; 241void io_manager::reg (check_watcher &w) { io_manager::reg (w, cw); }
242void io_manager::unreg (check_watcher &w) { io_manager::unreg (w, cw); }
243#endif
70 244
71 pfs.push_back (pfd); 245#if IOM_IDLE
72 iow.push_back (w); 246void io_manager::reg (idle_watcher &w) { io_manager::reg (w, iw); }
73} 247void io_manager::unreg (idle_watcher &w) { io_manager::unreg (w, iw); }
248#endif
74 249
250#if IOM_SIG
251static void
252sighandler (int signum)
253{
254 sw [signum - 1]->pending = true;
255
256 // we use a pipe for signal notifications, as most current
257 // OSes (Linux...) do not implement pselect correctly. ugh.
258 char ch = signum; // actual content not used
259 write (sigpipe[1], &ch, 1);
260}
261
75void io_manager::unreg (io_watcher *w) 262void io_manager::reg (sig_watcher &w)
76{ 263{
77 unsigned int sz = iow.size (); 264 init::required ();
78 unsigned int i = find (iow.begin (), iow.end (), w) - iow.begin ();
79 265
266 assert (0 < w.signum);
267
268 sw.reserve (w.signum);
269
270 while (sw.size () < w.signum) // pathetic
271 sw.push_back (0);
272
273 sig_vec *&sv = sw[w.signum - 1];
274
80 if (i != sz) 275 if (!sv)
81 { 276 {
82 if (sz == 1) 277 sv = new sig_vec;
278
279 sigaddset (&sigs, w.signum);
280 sigprocmask (SIG_BLOCK, &sigs, NULL);
281
282 struct sigaction sa;
283 sa.sa_handler = sighandler;
284 sigfillset (&sa.sa_mask);
285 sa.sa_flags = SA_RESTART;
286
287 if (sigaction (w.signum, &sa, 0))
83 { 288 {
289 perror ("io_manager: error while installing signal handler, ignoring.");
84 pfs.clear (); 290 abort ();
85 iow.clear ();
86 } 291 }
87 else if (i == sz - 1) 292
293 }
294
295 io_manager::reg (w, *sv);
296}
297
298void io_manager::unreg (sig_watcher &w)
299{
300 if (!w.active || !iom_valid)
301 return;
302
303 assert (0 < w.signum && w.signum <= sw.size ());
304
305 io_manager::unreg (w, *sw[w.signum - 1]);
306}
307
308void sig_watcher::start (int signum)
309{
310 stop ();
311 this->signum = signum;
312 io_manager::reg (*this);
313}
314#endif
315
316#if IOM_CHILD
317void io_manager::reg (child_watcher &w) { io_manager::reg (w, pw); }
318void io_manager::unreg (child_watcher &w) { io_manager::unreg (w, pw); }
319#endif
320
321void io_manager::loop ()
322{
323 init::required ();
324
325#if IOM_TIME
326 set_now ();
327#endif
328
329 for (;;)
330 {
331
332#if IOM_TIME
333 // call pending time watchers
334 {
335 bool activity;
336
337 do
338 {
339 activity = false;
340
341 for (int i = tw.size (); i--; )
342 if (!tw[i])
343 tw.erase_unordered (i);
344 else if (tw[i]->at <= NOW)
345 {
346 time_watcher &w = *tw[i];
347
348 unreg (w);
349 w.call (w);
350
351 activity = true;
352 }
353 }
354 while (activity);
355 }
356#endif
357
358#if IOM_CHECK
359 // call all check watchers
360 for (int i = cw.size (); i--; )
361 if (!cw[i])
362 cw.erase_unordered (i);
363 else
364 cw[i]->call (*cw[i]);
365#endif
366
367 struct TIMEVAL *to = 0;
368 struct TIMEVAL tval;
369
370#if IOM_IDLE
371 if (iw.size ())
88 { 372 {
89 iow.pop_back (); 373 tval.tv_sec = 0;
90 pfs.pop_back (); 374 tval.TV_FRAC = 0;
375 to = &tval;
91 } 376 }
92 else 377 else
378#endif
93 { 379 {
94 iow[i] = iow[sz - 1]; iow.pop_back (); 380#if IOM_TIME
95 pfs[i] = pfs[sz - 1]; pfs.pop_back (); 381 // find earliest active watcher
382 time_watcher *next = tw[0]; // the first time-watcher must exist at ALL times
383
384 for (io_manager_vec<time_watcher>::const_iterator i = tw.end (); i-- > tw.begin (); )
385 if (*i && (*i)->at < next->at)
386 next = *i;
387
388 if (next->at > NOW && next != tw[0])
389 {
390 double diff = next->at - NOW;
391 tval.tv_sec = (int)diff;
392 tval.TV_FRAC = (int) ((diff - tval.tv_sec) * TV_MULT);
393 to = &tval;
394 }
96 } 395 }
396#endif
397
398#if IOM_IO || IOM_SIG
399 fd_set rfd, wfd;
400
401 FD_ZERO (&rfd);
402 FD_ZERO (&wfd);
403
404 int fds = 0;
405
406# if IOM_IO
407 for (io_manager_vec<io_watcher>::const_iterator i = iow.end (); i-- > iow.begin (); )
408 if (*i)
409 {
410 if ((*i)->events & EVENT_READ ) FD_SET ((*i)->fd, &rfd);
411 if ((*i)->events & EVENT_WRITE) FD_SET ((*i)->fd, &wfd);
412
413 if ((*i)->fd >= fds) fds = (*i)->fd + 1;
414 }
415# endif
416
417 if (!to && !fds) //TODO: also check idle_watchers and check_watchers?
418 break; // no events
419
420# if IOM_SIG
421 FD_SET (sigpipe[0], &rfd);
422 if (sigpipe[0] >= fds) fds = sigpipe[0] + 1;
423# endif
424
425# if IOM_SIG
426 // there is no race, as we use a pipe for signals, so select
427 // will return if a signal is caught.
428 sigprocmask (SIG_UNBLOCK, &sigs, NULL);
429# endif
430 fds = select (fds, &rfd, &wfd, NULL, to);
431# if IOM_SIG
432 sigprocmask (SIG_BLOCK, &sigs, NULL);
433# endif
434
435# if IOM_TIME
436 {
437 // update time, try to compensate for gross non-monotonic time changes
438 tstamp diff = NOW;
439 set_now ();
440 diff = NOW - diff;
441
442 if (diff < 0)
443 for (io_manager_vec<time_watcher>::const_iterator i = tw.end (); i-- > tw.begin (); )
444 if (*i)
445 (*i)->at += diff;
446 }
447# endif
448
449 if (fds > 0)
450 {
451# if IOM_SIG
452 if (FD_ISSET (sigpipe[0], &rfd))
453 {
454 char ch;
455
456 while (read (sigpipe[0], &ch, 1) > 0)
457 ;
458
459 for (vector<sig_vec *>::iterator svp = sw.end (); svp-- > sw.begin (); )
460 if (*svp && (*svp)->pending)
461 {
462 sig_vec &sv = **svp;
463 for (int i = sv.size (); i--; )
464 if (!sv[i])
465 sv.erase_unordered (i);
466 else
467 sv[i]->call (*sv[i]);
468
469 sv.pending = false;
470 }
471 }
472# endif
473
474# if IOM_IO
475 for (int i = iow.size (); i--; )
476 if (!iow[i])
477 iow.erase_unordered (i);
478 else
479 {
480 io_watcher &w = *iow[i];
481 short revents = w.events;
482
483 if (!FD_ISSET (w.fd, &rfd)) revents &= ~EVENT_READ;
484 if (!FD_ISSET (w.fd, &wfd)) revents &= ~EVENT_WRITE;
485
486 if (revents)
487 w.call (w, revents);
488 }
489#endif
490 }
491 else if (fds < 0 && errno != EINTR)
492 {
493 perror ("io_manager: fatal error while waiting for I/O or time event, aborting.");
494 abort ();
495 }
496#if IOM_IDLE
497 else
498 for (int i = iw.size (); i--; )
499 if (!iw[i])
500 iw.erase_unordered (i);
501 else
502 iw[i]->call (*iw[i]);
503#endif
504
505#elif IOM_TIME
506 if (!to)
507 break;
508
509 select (0, 0, 0, 0, &to);
510 set_now ();
511#else
512 break;
513#endif
97 } 514 }
98} 515}
99 516
100void io_manager::reschedule_time_watchers ()
101{
102 make_heap (tw.begin (), tw.end (), lowest_first);
103}
104
105void io_manager::reg (time_watcher *w)
106{
107 if (w->registered)
108 slog (L_CRIT, "FATAL: io_manager::reg(time_watcher) called on already-registered watcher");
109
110 w->registered = true;
111
112 tw.push_back (w);
113 push_heap (tw.begin (), tw.end (), lowest_first);
114}
115
116void io_manager::unreg (time_watcher *w)
117{
118 if (w->registered)
119 {
120 unsigned int sz = tw.size ();
121 unsigned int i = find (tw.begin (), tw.end (), w) - tw.begin ();
122
123 if (i != sz)
124 {
125 if (i != sz - 1)
126 tw[i] = tw[sz - 1];
127
128 tw.pop_back ();
129 reschedule_time_watchers ();
130 }
131
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 {
153 // remove the first watcher
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);
167 }
168
169 int timeout = (int) ((tw[0]->at - NOW) * 1000);
170
171 int fds = poll (&pfs[0], pfs.size (), timeout);
172
173 set_now ();
174
175 for (unsigned int i = 0; fds > 0 && i < iow.size (); ++i)
176 if (pfs[i].revents)
177 {
178 --fds;
179 iow[i]->call (pfs[i].fd, pfs[i].revents);
180 }
181 }
182}
183
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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