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Comparing gvpe/src/iom.C (file contents):
Revision 1.12 by pcg, Thu Oct 16 02:41:21 2003 UTC vs.
Revision 1.37 by pcg, Thu Mar 29 17:35:20 2007 UTC

1/* 1/*
2 iom.C -- generic I/O multiplexor 2 iom.C -- generic I/O multiplexer
3 Copyright (C) 2003 Marc Lehmann <pcg@goof.com> 3 Copyright (C) 2003-2006 Marc Lehmann <gvpe@schmorp.de>
4 4
5 This file is part of GVPE.
6
5 This program is free software; you can redistribute it and/or modify 7 GVPE is free software; you can redistribute it and/or modify
6 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
7 the Free Software Foundation; either version 2 of the License, or 9 the Free Software Foundation; either version 2 of the License, or
8 (at your option) any later version. 10 (at your option) any later version.
9 11
10 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,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of 13 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU General Public License for more details. 15 GNU General Public License for more details.
14 16
15 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
16 along with this program; if not, write to the Free Software 18 along with gvpe; if not, write to the Free Software
17 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
18*/ 20*/
19 21
20#include "config.h" 22#include "iom.h"
21 23
24#include <cstdio>
25#include <cstdlib>
26#include <cerrno>
27#include <cassert>
28
29#include <sys/types.h>
22#include <sys/time.h> 30#include <sys/time.h>
23 31
24#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
25#include <functional> 42# include <csignal>
43# include <fcntl.h>
44#endif
26 45
27#include "gettext.h" 46// if the BSDs would at least be marginally POSIX-compatible.. *sigh*
47// until that happens, sys/select.h must come last
48#include <sys/select.h>
28 49
29#include "slog.h" 50#define TIMEVAL timeval
30#include "iom.h" 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
86{
87 void cb (time_watcher &w)
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;
31 99
32tstamp NOW; 100tstamp NOW;
101
102#if IOM_CHILD
103// sig_watcher for child signal(s)
104static struct sw0 : sig_watcher
105{
106 void cb (sig_watcher &w)
107 {
108 // SIGCHLD, call corresponding watchera
109 pid_t pid;
110 int status;
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 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
33bool iom_valid; 148static bool iom_valid;
34io_manager iom;
35 149
36inline bool earliest_first (const time_watcher *a, const time_watcher *b) 150// used for initialisation only
37{ 151static struct init {
38 return a->at > b->at; 152 init ()
39} 153 {
154#ifdef IOM_PREINIT
155 { IOM_PREINIT }
156#endif
157 iom_valid = true;
40 158
41void time_watcher::set (tstamp when) 159#if IOM_SIG
42{ 160 sigemptyset (&sigs);
43 at = when;
44 161
45 if (registered) 162 if (pipe (sigpipe))
46 iom.reschedule_time_watchers (); 163 {
47} 164 perror ("io_manager: unable to create signal pipe, aborting.");
165 abort ();
166 }
48 167
168 fcntl (sigpipe[0], F_SETFL, O_NONBLOCK); fcntl (sigpipe[0], F_SETFD, FD_CLOEXEC);
169 fcntl (sigpipe[1], F_SETFL, O_NONBLOCK); fcntl (sigpipe[1], F_SETFD, FD_CLOEXEC);
170#endif
171
172#if IOM_CHILD
173 sw0.start (SIGCHLD);
174#endif
175
176#if IOM_TIME
177 io_manager::set_now ();
178
179 tw0.start (TSTAMP_MAX);
180#endif
181
182#ifdef IOM_POSTINIT
183 { IOM_POSTINIT }
184#endif
185 }
186
187 ~init ()
188 {
189 iom_valid = false;
190 }
191
192 static void required ();
193} init;
194
195void
196init::required ()
197{
198 if (!iom_valid)
199 {
200 write (2, "io_manager: early registration attempt, aborting.\n",
201 sizeof ("io_manager: early registration attempt, aborting.\n") - 1);
202 abort ();
203 }
204}
205
206template<class watcher>
207void io_manager::reg (watcher &w, io_manager_vec<watcher> &queue)
208{
209 init::required ();
210
211 if (!w.active)
212 {
213 queue.push_back (&w);
214 w.active = queue.size ();
215 }
216}
217
218template<class watcher>
219void io_manager::unreg (watcher &w, io_manager_vec<watcher> &queue)
220{
221 if (!iom_valid)
222 return;
223
224 if (w.active)
225 {
226 queue [w.active - 1] = 0;
227 w.active = 0;
228 }
229}
230
231#if IOM_TIME
49void time_watcher::trigger () 232void time_watcher::trigger ()
50{ 233{
51 call (*this); 234 call (*this);
52 235 io_manager::reg (*this);
53 if (registered)
54 iom.reschedule_time_watchers ();
55 else
56 iom.reg (this);
57} 236}
58 237
59time_watcher::~time_watcher () 238void io_manager::reg (time_watcher &w) { io_manager::reg (w, tw); }
60{ 239void io_manager::unreg (time_watcher &w) { io_manager::unreg (w, tw); }
61 if (iom_valid) 240#endif
62 iom.unreg (this);
63}
64 241
65void io_watcher::set(int fd_, short events_) 242#if IOM_IO
66{ 243void io_manager::reg (io_watcher &w) { io_manager::reg (w, iow); }
67 fd = fd_; 244void io_manager::unreg (io_watcher &w) { io_manager::unreg (w, iow); }
68 events = events_; 245#endif
69 246
70 if (registered) 247#if IOM_CHECK
248void io_manager::reg (check_watcher &w) { io_manager::reg (w, cw); }
249void io_manager::unreg (check_watcher &w) { io_manager::unreg (w, cw); }
250#endif
251
252#if IOM_IDLE
253void io_manager::reg (idle_watcher &w) { io_manager::reg (w, iw); }
254void io_manager::unreg (idle_watcher &w) { io_manager::unreg (w, iw); }
255#endif
256
257#if IOM_SIG
258static void
259sighandler (int signum)
260{
261 sw [signum - 1]->pending = true;
262
263 // we use a pipe for signal notifications, as most current
264 // OSes (Linux...) do not implement pselect correctly. ugh.
265 char ch = signum; // actual content not used
266 write (sigpipe[1], &ch, 1);
267}
268
269void io_manager::reg (sig_watcher &w)
270{
271 init::required ();
272
273 assert (0 < w.signum);
274
275 sw.reserve (w.signum);
276
277 while (sw.size () < w.signum) // pathetic
278 sw.push_back (0);
279
280 sig_vec *&sv = sw[w.signum - 1];
281
282 if (!sv)
71 { 283 {
72 iom.unreg (this); 284 sv = new sig_vec;
73 iom.reg (this); 285
286 sigaddset (&sigs, w.signum);
287 sigprocmask (SIG_BLOCK, &sigs, NULL);
288
289 struct sigaction sa;
290 sa.sa_handler = sighandler;
291 sigfillset (&sa.sa_mask);
292 sa.sa_flags = SA_RESTART;
293
294 if (sigaction (w.signum, &sa, 0))
295 {
296 perror ("io_manager: error while installing signal handler, ignoring.");
297 abort ();
298 }
299
74 } 300 }
75}
76 301
77io_watcher::~io_watcher () 302 io_manager::reg (w, *sv);
78{
79 if (iom_valid)
80 iom.unreg (this);
81} 303}
82 304
83void io_manager::reg (io_watcher *w) 305void io_manager::unreg (sig_watcher &w)
84{ 306{
85 if (!w->registered) 307 if (!w.active || !iom_valid)
308 return;
309
310 assert (0 < w.signum && w.signum <= sw.size ());
311
312 io_manager::unreg (w, *sw[w.signum - 1]);
313}
314
315void sig_watcher::start (int signum)
316{
317 stop ();
318 this->signum = signum;
319 io_manager::reg (*this);
320}
321#endif
322
323#if IOM_CHILD
324void io_manager::reg (child_watcher &w) { io_manager::reg (w, pw); }
325void io_manager::unreg (child_watcher &w) { io_manager::unreg (w, pw); }
326#endif
327
328void io_manager::loop ()
329{
330 init::required ();
331
332#if IOM_TIME
333 set_now ();
334#endif
335
336 for (;;)
86 { 337 {
87 w->registered = true;
88 338
89 pollfd pfd; 339#if IOM_TIME
90 340 // call pending time watchers
91 pfd.fd = w->fd;
92 pfd.events = w->events;
93
94 pfs.push_back (pfd);
95 iow.push_back (w);
96 }
97}
98
99void io_manager::unreg (io_watcher *w)
100{
101 if (w->registered)
102 { 341 {
103 w->registered = false; 342 bool activity;
104 343
105 unsigned int sz = iow.size (); 344 do
106 unsigned int i = find (iow.begin (), iow.end (), w) - iow.begin (); 345 {
346 activity = false;
107 347
108 assert (i != sz); 348 for (int i = tw.size (); i--; )
349 if (!tw[i])
350 tw.erase_unordered (i);
351 else if (tw[i]->at <= NOW)
352 {
353 time_watcher &w = *tw[i];
354
355 unreg (w);
356 w.call (w);
109 357
110 if (sz == 1) 358 activity = true;
359 }
360 }
361 while (activity);
362 }
363#endif
364
365#if IOM_CHECK
366 // call all check watchers
367 for (int i = cw.size (); i--; )
368 if (!cw[i])
369 cw.erase_unordered (i);
370 else
371 cw[i]->call (*cw[i]);
372#endif
373
374 struct TIMEVAL *to = 0;
375 struct TIMEVAL tval;
376
377#if IOM_IDLE
378 if (iw.size ())
111 { 379 {
112 pfs.clear (); 380 tval.tv_sec = 0;
113 iow.clear (); 381 tval.TV_FRAC = 0;
114 } 382 to = &tval;
115 else if (i == sz - 1)
116 {
117 iow.pop_back ();
118 pfs.pop_back ();
119 } 383 }
120 else 384 else
385#endif
121 { 386 {
122 iow[i] = iow[sz - 1]; iow.pop_back (); 387#if IOM_TIME
123 pfs[i] = pfs[sz - 1]; pfs.pop_back (); 388 // find earliest active watcher
389 time_watcher *next = tw[0]; // the first time-watcher must exist at ALL times
390
391 for (io_manager_vec<time_watcher>::const_iterator i = tw.end (); i-- > tw.begin (); )
392 if (*i && (*i)->at < next->at)
393 next = *i;
394
395 if (next->at > NOW && next != tw[0])
396 {
397 double diff = next->at - NOW;
398 tval.tv_sec = (int)diff;
399 tval.TV_FRAC = (int) ((diff - tval.tv_sec) * TV_MULT);
400 to = &tval;
401 }
124 } 402 }
403#endif
404
405#if IOM_IO || IOM_SIG
406 fd_set rfd, wfd;
407
408 FD_ZERO (&rfd);
409 FD_ZERO (&wfd);
410
411 int fds = 0;
412
413# if IOM_IO
414 for (io_manager_vec<io_watcher>::const_iterator i = iow.end (); i-- > iow.begin (); )
415 if (*i)
416 {
417 if ((*i)->events & EVENT_READ ) FD_SET ((*i)->fd, &rfd);
418 if ((*i)->events & EVENT_WRITE) FD_SET ((*i)->fd, &wfd);
419
420 if ((*i)->fd >= fds) fds = (*i)->fd + 1;
421 }
422# endif
423
424 if (!to && !fds) //TODO: also check idle_watchers and check_watchers?
425 break; // no events
426
427# if IOM_SIG
428 FD_SET (sigpipe[0], &rfd);
429 if (sigpipe[0] >= fds) fds = sigpipe[0] + 1;
430# endif
431
432# if IOM_SIG
433 // there is no race, as we use a pipe for signals, so select
434 // will return if a signal is caught.
435 sigprocmask (SIG_UNBLOCK, &sigs, NULL);
436# endif
437 fds = select (fds, &rfd, &wfd, NULL, to);
438# if IOM_SIG
439 sigprocmask (SIG_BLOCK, &sigs, NULL);
440# endif
441
442# if IOM_TIME
443 {
444 // update time, try to compensate for gross non-monotonic time changes
445 tstamp diff = NOW;
446 set_now ();
447 diff = NOW - diff;
448
449 if (diff < 0)
450 for (io_manager_vec<time_watcher>::const_iterator i = tw.end (); i-- > tw.begin (); )
451 if (*i)
452 (*i)->at += diff;
453 }
454# endif
455
456 if (fds > 0)
457 {
458# if IOM_SIG
459 if (FD_ISSET (sigpipe[0], &rfd))
460 {
461 char ch;
462
463 while (read (sigpipe[0], &ch, 1) > 0)
464 ;
465
466 for (vector<sig_vec *>::iterator svp = sw.end (); svp-- > sw.begin (); )
467 if (*svp && (*svp)->pending)
468 {
469 sig_vec &sv = **svp;
470 for (int i = sv.size (); i--; )
471 if (!sv[i])
472 sv.erase_unordered (i);
473 else
474 sv[i]->call (*sv[i]);
475
476 sv.pending = false;
477 }
478 }
479# endif
480
481# if IOM_IO
482 for (int i = iow.size (); i--; )
483 if (!iow[i])
484 iow.erase_unordered (i);
485 else
486 {
487 io_watcher &w = *iow[i];
488 short revents = w.events;
489
490 if (!FD_ISSET (w.fd, &rfd)) revents &= ~EVENT_READ;
491 if (!FD_ISSET (w.fd, &wfd)) revents &= ~EVENT_WRITE;
492
493 if (revents)
494 w.call (w, revents);
495 }
496#endif
497 }
498 else if (fds < 0 && errno != EINTR)
499 {
500 perror ("io_manager: fatal error while waiting for I/O or time event, aborting.");
501 abort ();
502 }
503#if IOM_IDLE
504 else
505 for (int i = iw.size (); i--; )
506 if (!iw[i])
507 iw.erase_unordered (i);
508 else
509 iw[i]->call (*iw[i]);
510#endif
511
512#elif IOM_TIME
513 if (!to)
514 break;
515
516 select (0, 0, 0, 0, &to);
517 set_now ();
518#else
519 break;
520#endif
125 } 521 }
126} 522}
127 523
128void io_manager::reschedule_time_watchers ()
129{
130 make_heap (tw.begin (), tw.end (), earliest_first);
131}
132
133void io_manager::reg (time_watcher *w)
134{
135 if (!w->registered)
136 {
137 w->registered = true;
138
139 tw.push_back (w);
140 push_heap (tw.begin (), tw.end (), earliest_first);
141 }
142}
143
144void io_manager::unreg (time_watcher *w)
145{
146 if (w->registered)
147 {
148 w->registered = false;
149
150 unsigned int sz = tw.size ();
151 unsigned int i = find (tw.begin (), tw.end (), w) - tw.begin ();
152
153 assert (i != sz);
154
155 if (i != sz - 1)
156 tw[i] = tw[sz - 1];
157
158 tw.pop_back ();
159 reschedule_time_watchers ();
160 }
161}
162
163inline void set_now (void)
164{
165 struct timeval tv;
166
167 gettimeofday (&tv, 0);
168
169 NOW = (tstamp)tv.tv_sec + (tstamp)tv.tv_usec / 1000000;
170}
171
172void io_manager::loop ()
173{
174 set_now ();
175
176 for (;;)
177 {
178 while (tw[0]->at <= NOW)
179 {
180 // remove the first watcher
181 time_watcher *w = tw[0];
182
183 pop_heap (tw.begin (), tw.end (), earliest_first);
184 tw.pop_back ();
185
186 w->registered = false;
187
188 // call it
189 w->call (*w);
190
191 // re-add it if necessary
192 if (w->at >= 0 && !w->registered)
193 reg (w);
194 }
195
196 int timeout = (int) ((tw[0]->at - NOW) * 1000);
197
198 int fds = poll (&pfs[0], pfs.size (), timeout);
199
200 set_now ();
201
202 vector<io_watcher *>::iterator w;
203 vector<pollfd>::iterator p;
204
205 for (w = iow.begin (), p = pfs.begin ();
206 fds > 0 && w < iow.end ();
207 ++w, ++p)
208 if (p->revents)
209 {
210 --fds;
211
212 if (p->revents & POLLNVAL)
213 {
214 slog (L_ERR, _("io_watcher started on illegal file descriptor, disabling."));
215 (*w)->stop ();
216 }
217 else
218 (*w)->call (**w, p->revents);
219 }
220 }
221}
222
223void io_manager::idle_cb (time_watcher &w)
224{
225 w.at = NOW + 86400; // wake up every day, for no good reason
226}
227
228io_manager::io_manager ()
229{
230 iom_valid = true;
231
232 set_now ();
233 idle = new time_watcher (this, &io_manager::idle_cb);
234 idle->start (0);
235}
236
237io_manager::~io_manager ()
238{
239 iom_valid = false;
240}
241

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