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Comparing gvpe/src/iom.C (file contents):
Revision 1.5 by pcg, Wed Mar 26 01:58:46 2003 UTC vs.
Revision 1.22 by pcg, Thu Nov 11 17:41:55 2004 UTC

1/* 1/*
2 iom.C -- I/O multiplexor 2 iom.C -- generic I/O multiplexor
3 Copyright (C) 2003, 2004 Marc Lehmann <pcg@goof.com>
3 4
4 This program is free software; you can redistribute it and/or modify 5 This program is free software; you can redistribute it and/or modify
5 it under the terms of the GNU General Public License as published by 6 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 7 the Free Software Foundation; either version 2 of the License, or
7 (at your option) any later version. 8 (at your option) any later version.
… …
14 You should have received a copy of the GNU General Public License 15 You should have received a copy of the GNU General Public License
15 along with this program; if not, write to the Free Software 16 along with this program; if not, write to the Free Software
16 Foundation, Inc. 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 17 Foundation, Inc. 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
17*/ 18*/
18 19
19#include "config.h" 20#include "iom.h"
21
22#include <cstdio>
23#include <cstdlib>
24#include <cerrno>
20 25
21#include <sys/time.h> 26#include <sys/time.h>
22 27
23#include <algorithm> 28#include <assert.h>
24#include <functional>
25 29
26#include "slog.h" 30#if 1 // older unices need these includes for select (2)
31# include <unistd.h>
32# include <sys/types.h>
27#include "iom.h" 33# include <time.h>
34#endif
28 35
29inline bool lowest_first (const time_watcher *a, const time_watcher *b) 36// for IOM_SIG
30{ 37#if IOM_SIG
31 return a->at > b->at; 38# include <signal.h>
32} 39# include <fcntl.h>
40#endif
41
42// if the BSDs would at least be marginally POSIX-compatible.. *sigh*
43// until that happens, sys/select.h must come last
44#include <sys/select.h>
45
46// TSTAMP_MAX must still fit into a positive struct timeval
47#define TSTAMP_MAX (double)(1UL<<31)
48
49#define TIMEVAL timeval
50#define TV_FRAC tv_usec
51#define TV_MULT 1000000L
52
53#if IOM_IO
54static io_manager_vec<io_watcher> iow;
55#endif
56#if IOM_CHECK
57static io_manager_vec<check_watcher> cw;
58#endif
59#if IOM_TIME
60static io_manager_vec<time_watcher> tw;
61#endif
62#if IOM_IDLE
63static io_manager_vec<idle_watcher> iw;
64#endif
65#if IOM_SIG
66static int sigpipe[2]; // signal signalling pipe
67static sigset_t sigs;
68struct sig_vec : io_manager_vec<sig_watcher> {
69 int pending;
70 sig_vec ()
71 : pending (false)
72 { }
73};
74static vector<sig_vec *> sw;
75#endif
76
77// this is a dummy time watcher to ensure that the first
78// time watcher is _always_ valid, this gets rid of a lot
79// of null-pointer-checks
80// (must come _before_ iom is being defined)
81static struct tw0 : time_watcher
82 {
83 void cb (time_watcher &w)
84 {
85 // should never get called
86 // reached end-of-time, or tstamp has a bogus definition,
87 // or compiler initialisation order broken, or something else :)
88 abort ();
89 }
90
91 tw0 ()
92 : time_watcher (this, &tw0::cb)
93 { }
94 } tw0;
33 95
34tstamp NOW; 96tstamp NOW;
35 97
36io_manager iom; 98#if IOM_TIME
37 99inline void set_now (void)
38void time_watcher::set (tstamp when)
39{ 100{
40 iom.unreg (this); 101 struct timeval tv;
41 at = when;
42 iom.reg (this);
43}
44 102
103 gettimeofday (&tv, 0);
104 NOW = (tstamp)tv.tv_sec + (tstamp)tv.tv_usec / 1000000.;
105}
106#endif
107
108static bool iom_valid;
109
110// used for initialisation only
111static struct init {
112 init ()
113 {
114#if IOM_SIG
115 sigemptyset (&sigs);
116
117 if (pipe (sigpipe))
118 {
119 perror ("io_manager: unable to create signal pipe, aborting.");
120 abort ();
121 }
122
123 fcntl (sigpipe[0], F_SETFL, O_NONBLOCK);
124 fcntl (sigpipe[1], F_SETFL, O_NONBLOCK);
125#endif
126
127 iom_valid = true;
128
129#if IOM_TIME
130 set_now ();
131
132 tw0.start (TSTAMP_MAX);
133#endif
134 }
135
136 static void required ();
137} init;
138
139void
140init::required ()
141{
142 if (!iom_valid)
143 {
144 write (2, "io_manager: early registration attempt, aborting.\n",
145 sizeof ("io_manager: early registration attempt, aborting.\n") - 1);
146 abort ();
147 }
148}
149
150template<class watcher>
151void io_manager::reg (watcher &w, io_manager_vec<watcher> &queue)
152{
153 init::required ();
154
155 if (!w.active)
156 {
157 queue.push_back (&w);
158 w.active = queue.size ();
159 }
160}
161
162template<class watcher>
163void io_manager::unreg (watcher &w, io_manager_vec<watcher> &queue)
164{
165 if (!iom_valid)
166 return;
167
168 if (w.active)
169 {
170 queue [w.active - 1] = 0;
171 w.active = 0;
172 }
173}
174
175#if IOM_TIME
45void time_watcher::trigger () 176void time_watcher::trigger ()
46{ 177{
47 iom.unreg (this);
48 call (at); 178 call (*this);
49 iom.reg (this);
50}
51
52void time_watcher::start ()
53{
54 iom.unreg (this); 179 io_manager::reg (*this);
55 iom.reg (this);
56} 180}
57 181
58void io_manager::reg (int fd, short events, io_watcher *w) 182void io_manager::reg (time_watcher &w) { io_manager::reg (w, tw); }
59{ 183void io_manager::unreg (time_watcher &w) { io_manager::unreg (w, tw); }
60 pollfd pfd; 184#endif
61 185
62 pfd.fd = fd; 186#if IOM_IO
63 pfd.events = events; 187void io_manager::reg (io_watcher &w) { io_manager::reg (w, iow); }
188void io_manager::unreg (io_watcher &w) { io_manager::unreg (w, iow); }
189#endif
64 190
65 pfs.push_back (pfd); 191#if IOM_CHECK
66 iow.push_back (w); 192void io_manager::reg (check_watcher &w) { io_manager::reg (w, cw); }
67} 193void io_manager::unreg (check_watcher &w) { io_manager::unreg (w, cw); }
194#endif
68 195
196#if IOM_IDLE
197void io_manager::reg (idle_watcher &w) { io_manager::reg (w, iw); }
198void io_manager::unreg (idle_watcher &w) { io_manager::unreg (w, iw); }
199#endif
200
201#if IOM_SIG
202static void
203sighandler (int signum)
204{
205 sw [signum - 1]->pending = true;
206
207 // we use a pipe for signal notifications, as most current
208 // OSes (Linux...) do not implement pselect correctly. ugh.
209 char ch = signum; // actual content not used
210 write (sigpipe[1], &ch, 1);
211}
212
69void io_manager::unreg (const io_watcher *w) 213void io_manager::reg (sig_watcher &w)
70{ 214{
71 unsigned int sz = iow.size (); 215 assert (0 < w.signum);
72 unsigned int i = find (iow.begin (), iow.end (), w) - iow.begin ();
73 216
217 sw.reserve (w.signum);
218
219 while (sw.size () < w.signum) // pathetic
220 sw.push_back (0);
221
222 sig_vec *&sv = sw[w.signum - 1];
223
74 if (i != sz) 224 if (!sv)
75 { 225 {
76 if (sz == 1) 226 sv = new sig_vec;
227
228 sigaddset (&sigs, w.signum);
229 sigprocmask (SIG_BLOCK, &sigs, NULL);
230
231 struct sigaction sa;
232 sa.sa_handler = sighandler;
233 sigfillset (&sa.sa_mask);
234 sa.sa_flags = SA_RESTART;
235
236 if (sigaction (w.signum, &sa, 0))
77 { 237 {
238 perror ("io_manager: error while installing signal handler, ignoring.");
78 pfs.clear (); 239 abort ();
79 iow.clear ();
80 } 240 }
81 else if (i == sz - 1) 241
242 }
243
244 io_manager::reg (w, *sv);
245}
246
247void io_manager::unreg (sig_watcher &w)
248{
249 if (!w.active)
250 return;
251
252 assert (0 < w.signum && w.signum <= sw.size ());
253
254 io_manager::unreg (w, *sw[w.signum - 1]);
255}
256
257void sig_watcher::start (int signum)
258{
259 stop ();
260 this->signum = signum;
261 io_manager::reg (*this);
262}
263#endif
264
265void io_manager::loop ()
266{
267 init::required ();
268
269#if IOM_TIME
270 set_now ();
271#endif
272
273 for (;;)
274 {
275
276#if IOM_TIME
277 // call pending time watchers
278 {
279 bool activity;
280
281 do
282 {
283 activity = false;
284
285 for (int i = tw.size (); i--; )
286 if (!tw[i])
287 tw.erase_unordered (i);
288 else if (tw[i]->at <= NOW + IOM_ACCURACY)
289 {
290 time_watcher &w = *tw[i];
291
292 unreg (w);
293 w.call (w);
294
295 activity = true;
296 }
297 }
298 while (activity);
299 }
300#endif
301
302#if IOM_CHECK
303 // call all check watchers
304 for (int i = cw.size (); i--; )
305 if (!cw[i])
306 cw.erase_unordered (i);
307 else
308 cw[i]->call (*cw[i]);
309#endif
310
311 struct TIMEVAL *to = 0;
312 struct TIMEVAL tval;
313
314#if IOM_IDLE
315 if (iw.size ())
82 { 316 {
83 iow.pop_back (); 317 tval.tv_sec = 0;
84 pfs.pop_back (); 318 tval.TV_FRAC = 0;
319 to = &tval;
85 } 320 }
86 else 321 else
322#endif
87 { 323 {
88 iow[i] = iow[sz - 1]; iow.pop_back (); 324#if IOM_TIME
89 pfs[i] = pfs[sz - 1]; pfs.pop_back (); 325 // find earliest active watcher
326 time_watcher *next = tw[0]; // the first time-watcher must exist at ALL times
327
328 for (io_manager_vec<time_watcher>::const_iterator i = tw.end (); i-- > tw.begin (); )
329 if (*i && (*i)->at < next->at)
330 next = *i;
331
332 if (next->at > NOW && next != tw[0])
333 {
334 double diff = next->at - NOW;
335 tval.tv_sec = (int)diff;
336 tval.TV_FRAC = (int) ((diff - tval.tv_sec) * TV_MULT);
337 to = &tval;
338 }
90 } 339 }
91 } 340#endif
92}
93 341
94void io_manager::reg (time_watcher *w) 342#if IOM_IO || IOM_SIG
95{ 343 fd_set rfd, wfd;
96 tw.push_back (w);
97 push_heap (tw.begin (), tw.end (), lowest_first);
98}
99 344
100void io_manager::unreg (const time_watcher *w) 345 FD_ZERO (&rfd);
101{ 346 FD_ZERO (&wfd);
102 unsigned int sz = tw.size ();
103 unsigned int i = find (tw.begin (), tw.end (), w) - tw.begin ();
104 347
105 if (i != sz) 348 int fds = 0;
106 {
107 if (i != sz - 1)
108 tw[i] = tw[sz - 1];
109 349
110 tw.pop_back (); 350# if IOM_IO
111 make_heap (tw.begin (), tw.end (), lowest_first); 351 for (io_manager_vec<io_watcher>::const_iterator i = iow.end (); i-- > iow.begin (); )
112 } 352 if (*i)
113} 353 {
354 if ((*i)->events & EVENT_READ ) FD_SET ((*i)->fd, &rfd);
355 if ((*i)->events & EVENT_WRITE) FD_SET ((*i)->fd, &wfd);
114 356
115inline void set_now (void) 357 if ((*i)->fd >= fds) fds = (*i)->fd + 1;
116{ 358 }
117 struct timeval tv; 359# endif
118 360
119 gettimeofday (&tv, 0); 361 if (!to && !fds) //TODO: also check idle_watchers and check_watchers?
362 break; // no events
120 363
121 NOW = (tstamp)tv.tv_sec + (tstamp)tv.tv_usec / 1000000; 364# if IOM_SIG
122} 365 FD_SET (sigpipe[0], &rfd);
366 if (sigpipe[0] >= fds) fds = sigpipe[0] + 1;
367# endif
123 368
124void io_manager::loop () 369# if IOM_SIG
125{ 370 // there is no race, as we use a pipe for signals, so select
371 // will return if a signal is caught.
372 sigprocmask (SIG_UNBLOCK, &sigs, NULL);
373# endif
374 fds = select (fds, &rfd, &wfd, NULL, to);
375# if IOM_SIG
376 sigprocmask (SIG_BLOCK, &sigs, NULL);
377# endif
378
379# if IOM_TIME
126 set_now (); 380 set_now ();
381# endif
127 382
128 for (;;) 383 if (fds > 0)
129 {
130 while (tw[0]->at <= NOW)
131 { 384 {
132 pop_heap (tw.begin (), tw.end (), lowest_first); 385# if IOM_SIG
133 time_watcher *w = *(tw.end () - 1); 386 if (FD_ISSET (sigpipe[0], &rfd))
134
135 if (w->at >= 0)
136 { 387 {
137 w->call (w->at); 388 char ch;
138 push_heap (tw.begin (), tw.end (), lowest_first); 389
390 while (read (sigpipe[0], &ch, 1) > 0)
391 ;
392
393 for (sig_vec **svp = sw.end (); svp-- > sw.begin (); )
394 if (*svp && (*svp)->pending)
395 {
396 sig_vec &sv = **svp;
397 for (int i = sv.size (); i--; )
398 if (!sv[i])
399 sv.erase_unordered (i);
400 else
401 sv[i]->call (*sv[i]);
402
403 sv.pending = false;
404 }
139 } 405 }
406# endif
407
408# if IOM_IO
409 for (int i = iow.size (); i--; )
410 if (!iow[i])
411 iow.erase_unordered (i);
412 else
413 {
414 short revents = iow[i]->events;
415
416 if (!FD_ISSET (iow[i]->fd, &rfd)) revents &= ~EVENT_READ;
417 if (!FD_ISSET (iow[i]->fd, &wfd)) revents &= ~EVENT_WRITE;
418
419 if (revents)
420 iow[i]->call (*iow[i], revents);
421 }
422#endif
423 }
424 else if (fds < 0 && errno != EINTR)
425 {
426 perror ("io_manager: fatal error while waiting for I/O or time event, aborting.");
427 abort ();
428 }
429#if IOM_IDLE
430 else
431 for (int i = iw.size (); i--; )
432 if (!iw[i])
433 iw.erase_unordered (i);
140 else 434 else
141 tw.pop_back (); 435 iw[i]->call (*iw[i]);
142 } 436#endif
143 437
144 int timeout = (int) ((tw[0]->at - NOW) * 1000); 438#elif IOM_TIME
439 if (!to)
440 break;
145 441
146 int fds = poll (&pfs[0], pfs.size (), timeout); 442 select (0, 0, 0, 0, &to);
147
148 set_now (); 443 set_now ();
149 444#else
150 for (unsigned int i = iow.size (); fds > 0 && i--; ) 445 break;
151 if (pfs[i].revents) 446#endif
152 {
153 --fds;
154 iow[i]->call (pfs[i].revents);
155 }
156 } 447 }
157} 448}
158 449
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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