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Comparing gvpe/src/iom.C (file contents):
Revision 1.9 by pcg, Wed Apr 2 21:02:25 2003 UTC vs.
Revision 1.30 by pcg, Thu Mar 3 16:54:34 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. 59 Temple Place, Suite 330, Boston, MA 02111-1307 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 earliest_first (const time_watcher *a, const time_watcher *b) 48// TSTAMP_MAX must still fit into a positive struct timeval
30{ 49#define TSTAMP_MAX (double)(1UL<<31)
31 return a->at > b->at; 50
32} 51#define TIMEVAL timeval
52#define TV_FRAC tv_usec
53#define TV_MULT 1000000L
54
55#if IOM_IO
56static io_manager_vec<io_watcher> iow;
57#endif
58#if IOM_CHECK
59static io_manager_vec<check_watcher> cw;
60#endif
61#if IOM_TIME
62static io_manager_vec<time_watcher> tw;
63#endif
64#if IOM_IDLE
65static io_manager_vec<idle_watcher> iw;
66#endif
67#if IOM_SIG
68static int sigpipe[2]; // signal signalling pipe
69static sigset_t sigs;
70struct sig_vec : io_manager_vec<sig_watcher> {
71 int pending;
72 sig_vec ()
73 : pending (false)
74 { }
75};
76static vector<sig_vec *> sw;
77#endif
78
79// this is a dummy time watcher to ensure that the first
80// time watcher is _always_ valid, this gets rid of a lot
81// of null-pointer-checks
82// (must come _before_ iom is being defined)
83static struct tw0 : time_watcher
84 {
85 void cb (time_watcher &w)
86 {
87 // should never get called
88 // reached end-of-time, or tstamp has a bogus definition,
89 // or compiler initialisation order broken, or something else :)
90 abort ();
91 }
92
93 tw0 ()
94 : time_watcher (this, &tw0::cb)
95 { }
96 } tw0;
33 97
34tstamp NOW; 98tstamp NOW;
35 99
36io_manager iom; 100#if IOM_TIME
37 101tstamp io_manager::now ()
38void time_watcher::set (tstamp when)
39{ 102{
40 at = when; 103 struct timeval tv;
41 104
42 if (registered) 105 gettimeofday (&tv, 0);
43 iom.reschedule_time_watchers (); 106 return (tstamp)tv.tv_sec + (tstamp)tv.tv_usec / 1000000.;
44 else
45 iom.reg (this);
46} 107}
47 108
109void io_manager::set_now ()
110{
111 NOW = now ();
112}
113#endif
114
115static bool iom_valid;
116
117// used for initialisation only
118static struct init {
119 init ()
120 {
121#if IOM_SIG
122 sigemptyset (&sigs);
123
124 if (pipe (sigpipe))
125 {
126 perror ("io_manager: unable to create signal pipe, aborting.");
127 abort ();
128 }
129
130 fcntl (sigpipe[0], F_SETFL, O_NONBLOCK); fcntl (sigpipe[0], F_SETFD, FD_CLOEXEC);
131 fcntl (sigpipe[1], F_SETFL, O_NONBLOCK); fcntl (sigpipe[1], F_SETFD, FD_CLOEXEC);
132#endif
133
134 iom_valid = true;
135
136#if IOM_TIME
137 io_manager::set_now ();
138
139 tw0.start (TSTAMP_MAX);
140#endif
141 }
142
143 static void required ();
144} init;
145
146void
147init::required ()
148{
149 if (!iom_valid)
150 {
151 write (2, "io_manager: early registration attempt, aborting.\n",
152 sizeof ("io_manager: early registration attempt, aborting.\n") - 1);
153 abort ();
154 }
155}
156
157template<class watcher>
158void io_manager::reg (watcher &w, io_manager_vec<watcher> &queue)
159{
160 init::required ();
161
162 if (!w.active)
163 {
164 queue.push_back (&w);
165 w.active = queue.size ();
166 }
167}
168
169template<class watcher>
170void io_manager::unreg (watcher &w, io_manager_vec<watcher> &queue)
171{
172 if (!iom_valid)
173 return;
174
175 if (w.active)
176 {
177 queue [w.active - 1] = 0;
178 w.active = 0;
179 }
180}
181
182#if IOM_TIME
48void time_watcher::trigger () 183void time_watcher::trigger ()
49{ 184{
50 call (*this); 185 call (*this);
51 186 io_manager::reg (*this);
52 if (registered)
53 iom.reschedule_time_watchers ();
54 else
55 iom.reg (this);
56} 187}
57 188
58void time_watcher::start () 189void io_manager::reg (time_watcher &w) { io_manager::reg (w, tw); }
59{ 190void io_manager::unreg (time_watcher &w) { io_manager::unreg (w, tw); }
60 if (!registered) 191#endif
61 iom.reg (this);
62}
63 192
193#if IOM_IO
194void io_manager::reg (io_watcher &w) { io_manager::reg (w, iow); }
195void io_manager::unreg (io_watcher &w) { io_manager::unreg (w, iow); }
196#endif
197
198#if IOM_CHECK
199void io_manager::reg (check_watcher &w) { io_manager::reg (w, cw); }
200void io_manager::unreg (check_watcher &w) { io_manager::unreg (w, cw); }
201#endif
202
203#if IOM_IDLE
204void io_manager::reg (idle_watcher &w) { io_manager::reg (w, iw); }
205void io_manager::unreg (idle_watcher &w) { io_manager::unreg (w, iw); }
206#endif
207
208#if IOM_SIG
209static void
210sighandler (int signum)
211{
212 sw [signum - 1]->pending = true;
213
214 // we use a pipe for signal notifications, as most current
215 // OSes (Linux...) do not implement pselect correctly. ugh.
216 char ch = signum; // actual content not used
217 write (sigpipe[1], &ch, 1);
218}
219
64void io_manager::reg (io_watcher *w) 220void io_manager::reg (sig_watcher &w)
65{ 221{
66 pollfd pfd; 222 assert (0 < w.signum);
67 223
68 pfd.fd = w->fd; 224 sw.reserve (w.signum);
69 pfd.events = w->events;
70 225
71 pfs.push_back (pfd); 226 while (sw.size () < w.signum) // pathetic
72 iow.push_back (w); 227 sw.push_back (0);
73}
74 228
75void io_manager::unreg (io_watcher *w) 229 sig_vec *&sv = sw[w.signum - 1];
76{
77 unsigned int sz = iow.size ();
78 unsigned int i = find (iow.begin (), iow.end (), w) - iow.begin ();
79 230
80 if (i != sz) 231 if (!sv)
81 { 232 {
82 if (sz == 1) 233 sv = new sig_vec;
234
235 sigaddset (&sigs, w.signum);
236 sigprocmask (SIG_BLOCK, &sigs, NULL);
237
238 struct sigaction sa;
239 sa.sa_handler = sighandler;
240 sigfillset (&sa.sa_mask);
241 sa.sa_flags = SA_RESTART;
242
243 if (sigaction (w.signum, &sa, 0))
83 { 244 {
245 perror ("io_manager: error while installing signal handler, ignoring.");
84 pfs.clear (); 246 abort ();
85 iow.clear ();
86 } 247 }
87 else if (i == sz - 1) 248
249 }
250
251 io_manager::reg (w, *sv);
252}
253
254void io_manager::unreg (sig_watcher &w)
255{
256 if (!w.active)
257 return;
258
259 assert (0 < w.signum && w.signum <= sw.size ());
260
261 io_manager::unreg (w, *sw[w.signum - 1]);
262}
263
264void sig_watcher::start (int signum)
265{
266 stop ();
267 this->signum = signum;
268 io_manager::reg (*this);
269}
270#endif
271
272void io_manager::loop ()
273{
274 init::required ();
275
276#if IOM_TIME
277 set_now ();
278#endif
279
280 for (;;)
281 {
282
283#if IOM_TIME
284 // call pending time watchers
285 {
286 bool activity;
287
288 do
289 {
290 activity = false;
291
292 for (int i = tw.size (); i--; )
293 if (!tw[i])
294 tw.erase_unordered (i);
295 else if (tw[i]->at <= NOW)
296 {
297 time_watcher &w = *tw[i];
298
299 unreg (w);
300 w.call (w);
301
302 activity = true;
303 }
304 }
305 while (activity);
306 }
307#endif
308
309#if IOM_CHECK
310 // call all check watchers
311 for (int i = cw.size (); i--; )
312 if (!cw[i])
313 cw.erase_unordered (i);
314 else
315 cw[i]->call (*cw[i]);
316#endif
317
318 struct TIMEVAL *to = 0;
319 struct TIMEVAL tval;
320
321#if IOM_IDLE
322 if (iw.size ())
88 { 323 {
89 iow.pop_back (); 324 tval.tv_sec = 0;
90 pfs.pop_back (); 325 tval.TV_FRAC = 0;
326 to = &tval;
91 } 327 }
92 else 328 else
329#endif
93 { 330 {
94 iow[i] = iow[sz - 1]; iow.pop_back (); 331#if IOM_TIME
95 pfs[i] = pfs[sz - 1]; pfs.pop_back (); 332 // find earliest active watcher
333 time_watcher *next = tw[0]; // the first time-watcher must exist at ALL times
334
335 for (io_manager_vec<time_watcher>::const_iterator i = tw.end (); i-- > tw.begin (); )
336 if (*i && (*i)->at < next->at)
337 next = *i;
338
339 if (next->at > NOW && next != tw[0])
340 {
341 double diff = next->at - NOW;
342 tval.tv_sec = (int)diff;
343 tval.TV_FRAC = (int) ((diff - tval.tv_sec) * TV_MULT);
344 to = &tval;
345 }
96 } 346 }
97 } 347#endif
98}
99 348
100void io_manager::reschedule_time_watchers () 349#if IOM_IO || IOM_SIG
101{ 350 fd_set rfd, wfd;
102 make_heap (tw.begin (), tw.end (), earliest_first);
103}
104 351
105void io_manager::reg (time_watcher *w) 352 FD_ZERO (&rfd);
106{ 353 FD_ZERO (&wfd);
107 if (w->registered)
108 slog (L_CRIT, "FATAL: io_manager::reg(time_watcher) called on already-registered watcher");
109 354
110 w->registered = true; 355 int fds = 0;
111 356
112 tw.push_back (w); 357# if IOM_IO
113 push_heap (tw.begin (), tw.end (), earliest_first); 358 for (io_manager_vec<io_watcher>::const_iterator i = iow.end (); i-- > iow.begin (); )
114} 359 if (*i)
360 {
361 if ((*i)->events & EVENT_READ ) FD_SET ((*i)->fd, &rfd);
362 if ((*i)->events & EVENT_WRITE) FD_SET ((*i)->fd, &wfd);
115 363
116void io_manager::unreg (time_watcher *w) 364 if ((*i)->fd >= fds) fds = (*i)->fd + 1;
117{ 365 }
118 if (w->registered) 366# endif
367
368 if (!to && !fds) //TODO: also check idle_watchers and check_watchers?
369 break; // no events
370
371# if IOM_SIG
372 FD_SET (sigpipe[0], &rfd);
373 if (sigpipe[0] >= fds) fds = sigpipe[0] + 1;
374# endif
375
376# if IOM_SIG
377 // there is no race, as we use a pipe for signals, so select
378 // will return if a signal is caught.
379 sigprocmask (SIG_UNBLOCK, &sigs, NULL);
380# endif
381 fds = select (fds, &rfd, &wfd, NULL, to);
382# if IOM_SIG
383 sigprocmask (SIG_BLOCK, &sigs, NULL);
384# endif
385
386# if IOM_TIME
119 { 387 {
120 unsigned int sz = tw.size (); 388 // update time, try to compensate for gross non-monotonic time changes
121 unsigned int i = find (tw.begin (), tw.end (), w) - tw.begin (); 389 tstamp diff = NOW;
390 set_now ();
391 diff = NOW - diff;
122 392
123 if (i != sz) 393 if (diff < 0)
394 for (io_manager_vec<time_watcher>::const_iterator i = tw.end (); i-- > tw.begin (); )
395 if (*i)
396 (*i)->at += diff;
397 }
398# endif
399
400 if (fds > 0)
124 { 401 {
125 if (i != sz - 1) 402# if IOM_SIG
126 tw[i] = tw[sz - 1]; 403 if (FD_ISSET (sigpipe[0], &rfd))
404 {
405 char ch;
127 406
128 tw.pop_back (); 407 while (read (sigpipe[0], &ch, 1) > 0)
129 reschedule_time_watchers (); 408 ;
409
410 for (vector<sig_vec *>::iterator svp = sw.end (); svp-- > sw.begin (); )
411 if (*svp && (*svp)->pending)
412 {
413 sig_vec &sv = **svp;
414 for (int i = sv.size (); i--; )
415 if (!sv[i])
416 sv.erase_unordered (i);
417 else
418 sv[i]->call (*sv[i]);
419
420 sv.pending = false;
421 }
422 }
423# endif
424
425# if IOM_IO
426 for (int i = iow.size (); i--; )
427 if (!iow[i])
428 iow.erase_unordered (i);
429 else
430 {
431 io_watcher &w = *iow[i];
432 short revents = w.events;
433
434 if (!FD_ISSET (w.fd, &rfd)) revents &= ~EVENT_READ;
435 if (!FD_ISSET (w.fd, &wfd)) revents &= ~EVENT_WRITE;
436
437 if (revents)
438 w.call (w, revents);
439 }
440#endif
130 } 441 }
131 442 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 { 443 {
153 // remove the first watcher 444 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 (), earliest_first);
157 tw.pop_back ();
158
159 w->registered = false;
160
161 // call it
162 w->call (*w);
163
164 // re-add it if necessary
165 if (w->at >= 0 && !w->registered)
166 reg (w); 445 abort ();
167 } 446 }
447#if IOM_IDLE
448 else
449 for (int i = iw.size (); i--; )
450 if (!iw[i])
451 iw.erase_unordered (i);
452 else
453 iw[i]->call (*iw[i]);
454#endif
168 455
169 int timeout = (int) ((tw[0]->at - NOW) * 1000); 456#elif IOM_TIME
457 if (!to)
458 break;
170 459
171 int fds = poll (&pfs[0], pfs.size (), timeout); 460 select (0, 0, 0, 0, &to);
172
173 set_now (); 461 set_now ();
174 462#else
175 vector<io_watcher *>::iterator w; 463 break;
176 vector<pollfd>::iterator p; 464#endif
177
178 for (w = iow.begin (), p = pfs.begin ();
179 fds > 0 && w < iow.end ();
180 ++w, ++p)
181 if (p->revents)
182 {
183 --fds;
184 (*w)->call (**w, p->revents);
185 }
186 } 465 }
187} 466}
188 467
189void io_manager::idle_cb (time_watcher &w)
190{
191 w.at = NOW + 86400; // wake up every day, for no good reason
192}
193
194io_manager::io_manager ()
195{
196 set_now ();
197 idle = new time_watcher (this, &io_manager::idle_cb);
198 idle->start (0);
199}
200
201io_manager::~io_manager ()
202{
203 //
204}
205

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