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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 1.35 by pcg, Sat Jan 28 12:02:51 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 iom.unreg (this); 106 void cb (sig_watcher &w)
41 at = when; 107 {
42 iom.reg (this); 108 // SIGCHLD, call corresponding watchera
43} 109 pid_t pid;
110 int status;
44 111
112 while ((pid = waitpid (-1, &status, WNOHANG)) > 0)
113 for (int i = pw.size (); i--; )
114 {
115 child_watcher *w = pw[i];
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
128 sw0 ()
129 : sig_watcher (this, &sw0::cb)
130 { }
131} sw0;
132#endif
133
134#if IOM_TIME
135tstamp io_manager::now ()
136{
137 struct timeval tv;
138
139 gettimeofday (&tv, 0);
140 return (tstamp)tv.tv_sec + (tstamp)tv.tv_usec / 1000000.;
141}
142
143void io_manager::set_now ()
144{
145 NOW = now ();
146}
147#endif
148
149static bool iom_valid;
150
151// used for initialisation only
152static struct init {
153 init ()
154 {
155 iom_valid = true;
156
157#if IOM_SIG
158 sigemptyset (&sigs);
159
160 if (pipe (sigpipe))
161 {
162 perror ("io_manager: unable to create signal pipe, aborting.");
163 abort ();
164 }
165
166 fcntl (sigpipe[0], F_SETFL, O_NONBLOCK); fcntl (sigpipe[0], F_SETFD, FD_CLOEXEC);
167 fcntl (sigpipe[1], F_SETFL, O_NONBLOCK); fcntl (sigpipe[1], F_SETFD, FD_CLOEXEC);
168#endif
169
170#if IOM_CHILD
171 sw0.start (SIGCHLD);
172#endif
173
174#if IOM_TIME
175 io_manager::set_now ();
176
177 tw0.start (TSTAMP_MAX);
178#endif
179 }
180
181 ~init ()
182 {
183 iom_valid = false;
184 }
185
186 static void required ();
187} init;
188
189void
190init::required ()
191{
192 if (!iom_valid)
193 {
194 write (2, "io_manager: early registration attempt, aborting.\n",
195 sizeof ("io_manager: early registration attempt, aborting.\n") - 1);
196 abort ();
197 }
198}
199
200template<class watcher>
201void io_manager::reg (watcher &w, io_manager_vec<watcher> &queue)
202{
203 init::required ();
204
205 if (!w.active)
206 {
207 queue.push_back (&w);
208 w.active = queue.size ();
209 }
210}
211
212template<class watcher>
213void io_manager::unreg (watcher &w, io_manager_vec<watcher> &queue)
214{
215 if (!iom_valid)
216 return;
217
218 if (w.active)
219 {
220 queue [w.active - 1] = 0;
221 w.active = 0;
222 }
223}
224
225#if IOM_TIME
45void time_watcher::trigger () 226void time_watcher::trigger ()
46{ 227{
47 iom.unreg (this);
48 call (at); 228 call (*this);
49 iom.reg (this);
50}
51
52void time_watcher::start ()
53{
54 iom.unreg (this); 229 io_manager::reg (*this);
55 iom.reg (this);
56} 230}
57 231
58void io_manager::reg (int fd, short events, io_watcher *w) 232void io_manager::reg (time_watcher &w) { io_manager::reg (w, tw); }
59{ 233void io_manager::unreg (time_watcher &w) { io_manager::unreg (w, tw); }
60 pollfd pfd; 234#endif
61 235
62 pfd.fd = fd; 236#if IOM_IO
63 pfd.events = events; 237void io_manager::reg (io_watcher &w) { io_manager::reg (w, iow); }
238void io_manager::unreg (io_watcher &w) { io_manager::unreg (w, iow); }
239#endif
64 240
65 pfs.push_back (pfd); 241#if IOM_CHECK
66 iow.push_back (w); 242void io_manager::reg (check_watcher &w) { io_manager::reg (w, cw); }
67} 243void io_manager::unreg (check_watcher &w) { io_manager::unreg (w, cw); }
244#endif
68 245
246#if IOM_IDLE
247void io_manager::reg (idle_watcher &w) { io_manager::reg (w, iw); }
248void io_manager::unreg (idle_watcher &w) { io_manager::unreg (w, iw); }
249#endif
250
251#if IOM_SIG
252static void
253sighandler (int signum)
254{
255 sw [signum - 1]->pending = true;
256
257 // we use a pipe for signal notifications, as most current
258 // OSes (Linux...) do not implement pselect correctly. ugh.
259 char ch = signum; // actual content not used
260 write (sigpipe[1], &ch, 1);
261}
262
69void io_manager::unreg (io_watcher *w) 263void io_manager::reg (sig_watcher &w)
70{ 264{
71 unsigned int sz = iow.size (); 265 init::required ();
72 unsigned int i = find (iow.begin (), iow.end (), w) - iow.begin ();
73 266
267 assert (0 < w.signum);
268
269 sw.reserve (w.signum);
270
271 while (sw.size () < w.signum) // pathetic
272 sw.push_back (0);
273
274 sig_vec *&sv = sw[w.signum - 1];
275
74 if (i != sz) 276 if (!sv)
75 { 277 {
76 if (sz == 1) 278 sv = new sig_vec;
279
280 sigaddset (&sigs, w.signum);
281 sigprocmask (SIG_BLOCK, &sigs, NULL);
282
283 struct sigaction sa;
284 sa.sa_handler = sighandler;
285 sigfillset (&sa.sa_mask);
286 sa.sa_flags = SA_RESTART;
287
288 if (sigaction (w.signum, &sa, 0))
77 { 289 {
290 perror ("io_manager: error while installing signal handler, ignoring.");
78 pfs.clear (); 291 abort ();
79 iow.clear ();
80 } 292 }
81 else if (i == sz - 1) 293
294 }
295
296 io_manager::reg (w, *sv);
297}
298
299void io_manager::unreg (sig_watcher &w)
300{
301 if (!w.active || !iom_valid)
302 return;
303
304 assert (0 < w.signum && w.signum <= sw.size ());
305
306 io_manager::unreg (w, *sw[w.signum - 1]);
307}
308
309void sig_watcher::start (int signum)
310{
311 stop ();
312 this->signum = signum;
313 io_manager::reg (*this);
314}
315#endif
316
317#if IOM_CHILD
318void io_manager::reg (child_watcher &w) { io_manager::reg (w, pw); }
319void io_manager::unreg (child_watcher &w) { io_manager::unreg (w, pw); }
320#endif
321
322void io_manager::loop ()
323{
324 init::required ();
325
326#if IOM_TIME
327 set_now ();
328#endif
329
330 for (;;)
331 {
332
333#if IOM_TIME
334 // call pending time watchers
335 {
336 bool activity;
337
338 do
339 {
340 activity = false;
341
342 for (int i = tw.size (); i--; )
343 if (!tw[i])
344 tw.erase_unordered (i);
345 else if (tw[i]->at <= NOW)
346 {
347 time_watcher &w = *tw[i];
348
349 unreg (w);
350 w.call (w);
351
352 activity = true;
353 }
354 }
355 while (activity);
356 }
357#endif
358
359#if IOM_CHECK
360 // call all check watchers
361 for (int i = cw.size (); i--; )
362 if (!cw[i])
363 cw.erase_unordered (i);
364 else
365 cw[i]->call (*cw[i]);
366#endif
367
368 struct TIMEVAL *to = 0;
369 struct TIMEVAL tval;
370
371#if IOM_IDLE
372 if (iw.size ())
82 { 373 {
83 iow.pop_back (); 374 tval.tv_sec = 0;
84 pfs.pop_back (); 375 tval.TV_FRAC = 0;
376 to = &tval;
85 } 377 }
86 else 378 else
379#endif
87 { 380 {
88 iow[i] = iow[sz - 1]; iow.pop_back (); 381#if IOM_TIME
89 pfs[i] = pfs[sz - 1]; pfs.pop_back (); 382 // find earliest active watcher
383 time_watcher *next = tw[0]; // the first time-watcher must exist at ALL times
384
385 for (io_manager_vec<time_watcher>::const_iterator i = tw.end (); i-- > tw.begin (); )
386 if (*i && (*i)->at < next->at)
387 next = *i;
388
389 if (next->at > NOW && next != tw[0])
390 {
391 double diff = next->at - NOW;
392 tval.tv_sec = (int)diff;
393 tval.TV_FRAC = (int) ((diff - tval.tv_sec) * TV_MULT);
394 to = &tval;
395 }
90 } 396 }
397#endif
398
399#if IOM_IO || IOM_SIG
400 fd_set rfd, wfd;
401
402 FD_ZERO (&rfd);
403 FD_ZERO (&wfd);
404
405 int fds = 0;
406
407# if IOM_IO
408 for (io_manager_vec<io_watcher>::const_iterator i = iow.end (); i-- > iow.begin (); )
409 if (*i)
410 {
411 if ((*i)->events & EVENT_READ ) FD_SET ((*i)->fd, &rfd);
412 if ((*i)->events & EVENT_WRITE) FD_SET ((*i)->fd, &wfd);
413
414 if ((*i)->fd >= fds) fds = (*i)->fd + 1;
415 }
416# endif
417
418 if (!to && !fds) //TODO: also check idle_watchers and check_watchers?
419 break; // no events
420
421# if IOM_SIG
422 FD_SET (sigpipe[0], &rfd);
423 if (sigpipe[0] >= fds) fds = sigpipe[0] + 1;
424# endif
425
426# if IOM_SIG
427 // there is no race, as we use a pipe for signals, so select
428 // will return if a signal is caught.
429 sigprocmask (SIG_UNBLOCK, &sigs, NULL);
430# endif
431 fds = select (fds, &rfd, &wfd, NULL, to);
432# if IOM_SIG
433 sigprocmask (SIG_BLOCK, &sigs, NULL);
434# endif
435
436# if IOM_TIME
437 {
438 // update time, try to compensate for gross non-monotonic time changes
439 tstamp diff = NOW;
440 set_now ();
441 diff = NOW - diff;
442
443 if (diff < 0)
444 for (io_manager_vec<time_watcher>::const_iterator i = tw.end (); i-- > tw.begin (); )
445 if (*i)
446 (*i)->at += diff;
447 }
448# endif
449
450 if (fds > 0)
451 {
452# if IOM_SIG
453 if (FD_ISSET (sigpipe[0], &rfd))
454 {
455 char ch;
456
457 while (read (sigpipe[0], &ch, 1) > 0)
458 ;
459
460 for (vector<sig_vec *>::iterator svp = sw.end (); svp-- > sw.begin (); )
461 if (*svp && (*svp)->pending)
462 {
463 sig_vec &sv = **svp;
464 for (int i = sv.size (); i--; )
465 if (!sv[i])
466 sv.erase_unordered (i);
467 else
468 sv[i]->call (*sv[i]);
469
470 sv.pending = false;
471 }
472 }
473# endif
474
475# if IOM_IO
476 for (int i = iow.size (); i--; )
477 if (!iow[i])
478 iow.erase_unordered (i);
479 else
480 {
481 io_watcher &w = *iow[i];
482 short revents = w.events;
483
484 if (!FD_ISSET (w.fd, &rfd)) revents &= ~EVENT_READ;
485 if (!FD_ISSET (w.fd, &wfd)) revents &= ~EVENT_WRITE;
486
487 if (revents)
488 w.call (w, revents);
489 }
490#endif
491 }
492 else if (fds < 0 && errno != EINTR)
493 {
494 perror ("io_manager: fatal error while waiting for I/O or time event, aborting.");
495 abort ();
496 }
497#if IOM_IDLE
498 else
499 for (int i = iw.size (); i--; )
500 if (!iw[i])
501 iw.erase_unordered (i);
502 else
503 iw[i]->call (*iw[i]);
504#endif
505
506#elif IOM_TIME
507 if (!to)
508 break;
509
510 select (0, 0, 0, 0, &to);
511 set_now ();
512#else
513 break;
514#endif
91 } 515 }
92} 516}
93 517
94void io_manager::reg (time_watcher *w)
95{
96 tw.push_back (w);
97 push_heap (tw.begin (), tw.end (), lowest_first);
98}
99
100void io_manager::unreg (time_watcher *w)
101{
102 unsigned int sz = tw.size ();
103 unsigned int i = find (tw.begin (), tw.end (), w) - tw.begin ();
104
105 if (i != sz)
106 {
107 if (i != sz - 1)
108 tw[i] = tw[sz - 1];
109
110 tw.pop_back ();
111 make_heap (tw.begin (), tw.end (), lowest_first);
112 }
113}
114
115inline void set_now (void)
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 {
132 pop_heap (tw.begin (), tw.end (), lowest_first);
133 time_watcher *w = *(tw.end () - 1);
134
135 if (w->at >= 0)
136 {
137 w->call (w->at);
138 push_heap (tw.begin (), tw.end (), lowest_first);
139 }
140 else
141 tw.pop_back ();
142 }
143
144 int timeout = (int) ((tw[0]->at - NOW) * 1000);
145
146 int fds = poll (&pfs[0], pfs.size (), timeout);
147
148 set_now ();
149
150 for (unsigned int i = iow.size (); fds > 0 && i--; )
151 if (pfs[i].revents)
152 {
153 --fds;
154 iow[i]->call (pfs[i].revents);
155 }
156 }
157}
158
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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