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Comparing gvpe/src/iom.C (file contents):
Revision 1.10 by pcg, Fri Apr 4 05:26:45 2003 UTC vs.
Revision 1.24 by pcg, Fri Nov 12 12:49:12 2004 UTC

1/* 1/*
2 iom.C -- I/O multiplexor 2 iom.C -- generic I/O multiplexer
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
35
36// for IOM_SIG
37#if IOM_SIG
38# include <signal.h>
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;
28 95
29tstamp NOW; 96tstamp NOW;
97
98#if IOM_TIME
99inline void set_now (void)
100{
101 struct timeval tv;
102
103 gettimeofday (&tv, 0);
104 NOW = (tstamp)tv.tv_sec + (tstamp)tv.tv_usec / 1000000.;
105}
106#endif
107
30bool iom_valid; 108static bool iom_valid;
31io_manager iom;
32 109
33inline bool earliest_first (const time_watcher *a, const time_watcher *b) 110// used for initialisation only
34{ 111static struct init {
35 return a->at > b->at; 112 init ()
36} 113 {
114#if IOM_SIG
115 sigemptyset (&sigs);
37 116
38void time_watcher::set (tstamp when) 117 if (pipe (sigpipe))
39{ 118 {
40 at = when; 119 perror ("io_manager: unable to create signal pipe, aborting.");
120 abort ();
121 }
41 122
42 if (registered) 123 fcntl (sigpipe[0], F_SETFL, O_NONBLOCK);
43 iom.reschedule_time_watchers (); 124 fcntl (sigpipe[1], F_SETFL, O_NONBLOCK);
44 else 125#endif
45 iom.reg (this);
46}
47 126
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
48void time_watcher::trigger () 176void time_watcher::trigger ()
49{ 177{
50 call (*this); 178 call (*this);
51 179 io_manager::reg (*this);
52 if (registered)
53 iom.reschedule_time_watchers ();
54 else
55 iom.reg (this);
56} 180}
57 181
58void time_watcher::start () 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 if (!registered) 184#endif
61 iom.reg (this);
62}
63 185
64time_watcher::~time_watcher () 186#if IOM_IO
65{ 187void io_manager::reg (io_watcher &w) { io_manager::reg (w, iow); }
66 if (iom_valid) 188void io_manager::unreg (io_watcher &w) { io_manager::unreg (w, iow); }
67 iom.unreg (this); 189#endif
68}
69 190
70io_watcher::~io_watcher () 191#if IOM_CHECK
71{ 192void io_manager::reg (check_watcher &w) { io_manager::reg (w, cw); }
72 if (iom_valid) 193void io_manager::unreg (check_watcher &w) { io_manager::unreg (w, cw); }
73 iom.unreg (this); 194#endif
74}
75 195
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
76void io_manager::reg (io_watcher *w) 213void io_manager::reg (sig_watcher &w)
77{ 214{
78 pollfd pfd; 215 assert (0 < w.signum);
79 216
80 pfs.push_back (pfd); 217 sw.reserve (w.signum);
218
219 while (sw.size () < w.signum) // pathetic
81 iow.push_back (w); 220 sw.push_back (0);
82 221
83 w->p = &(*(pfs.end () - 1)); 222 sig_vec *&sv = sw[w.signum - 1];
84}
85 223
86void io_manager::unreg (io_watcher *w) 224 if (!sv)
87{
88 if (w->p)
89 { 225 {
90 unsigned int sz = iow.size (); 226 sv = new sig_vec;
91 unsigned int i = find (iow.begin (), iow.end (), w) - iow.begin ();
92 227
93 assert (i != sz); 228 sigaddset (&sigs, w.signum);
229 sigprocmask (SIG_BLOCK, &sigs, NULL);
94 230
95 if (sz == 1) 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))
96 { 237 {
238 perror ("io_manager: error while installing signal handler, ignoring.");
97 pfs.clear (); 239 abort ();
98 iow.clear ();
99 } 240 }
100 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)
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 ())
101 { 316 {
102 iow.pop_back (); 317 tval.tv_sec = 0;
103 pfs.pop_back (); 318 tval.TV_FRAC = 0;
319 to = &tval;
104 } 320 }
105 else 321 else
322#endif
106 { 323 {
107 iow[i] = iow[sz - 1]; iow.pop_back (); 324#if IOM_TIME
108 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 }
109 } 339 }
340#endif
110 341
111 w->p = 0; 342#if IOM_IO || IOM_SIG
112 } 343 fd_set rfd, wfd;
113}
114 344
115void io_manager::reschedule_time_watchers () 345 FD_ZERO (&rfd);
116{ 346 FD_ZERO (&wfd);
117 make_heap (tw.begin (), tw.end (), earliest_first);
118}
119 347
120void io_manager::reg (time_watcher *w) 348 int fds = 0;
121{
122 w->registered = true;
123 349
124 tw.push_back (w); 350# if IOM_IO
125 push_heap (tw.begin (), tw.end (), earliest_first); 351 for (io_manager_vec<io_watcher>::const_iterator i = iow.end (); i-- > iow.begin (); )
126} 352 if (*i)
353 {
354 if ((*i)->events & EVENT_READ ) FD_SET ((*i)->fd, &rfd);
355 if ((*i)->events & EVENT_WRITE) FD_SET ((*i)->fd, &wfd);
127 356
128void io_manager::unreg (time_watcher *w) 357 if ((*i)->fd >= fds) fds = (*i)->fd + 1;
129{ 358 }
130 if (w->registered) 359# endif
131 {
132 unsigned int sz = tw.size ();
133 unsigned int i = find (tw.begin (), tw.end (), w) - tw.begin ();
134 360
135 assert (i != sz); 361 if (!to && !fds) //TODO: also check idle_watchers and check_watchers?
136 362 break; // no events
137 if (i != sz - 1)
138 tw[i] = tw[sz - 1];
139 363
140 tw.pop_back (); 364# if IOM_SIG
141 reschedule_time_watchers (); 365 FD_SET (sigpipe[0], &rfd);
366 if (sigpipe[0] >= fds) fds = sigpipe[0] + 1;
367# endif
142 368
143 w->registered = false; 369# if IOM_SIG
144 } 370 // there is no race, as we use a pipe for signals, so select
145} 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
146 378
147inline void set_now (void) 379# if IOM_TIME
148{
149 struct timeval tv;
150
151 gettimeofday (&tv, 0);
152
153 NOW = (tstamp)tv.tv_sec + (tstamp)tv.tv_usec / 1000000;
154}
155
156void io_manager::loop ()
157{
158 set_now (); 380 set_now ();
381# endif
159 382
160 for (;;) 383 if (fds > 0)
161 {
162 while (tw[0]->at <= NOW)
163 { 384 {
164 // remove the first watcher 385# if IOM_SIG
165 time_watcher *w = tw[0]; 386 if (FD_ISSET (sigpipe[0], &rfd))
387 {
388 char ch;
166 389
167 pop_heap (tw.begin (), tw.end (), earliest_first); 390 while (read (sigpipe[0], &ch, 1) > 0)
168 tw.pop_back (); 391 ;
169 392
170 w->registered = false; 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]);
171 402
172 // call it 403 sv.pending = false;
173 w->call (*w); 404 }
405 }
406# endif
174 407
175 // re-add it if necessary 408# if IOM_IO
176 if (w->at >= 0 && !w->registered) 409 for (int i = iow.size (); i--; )
177 reg (w); 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
178 } 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);
434 else
435 iw[i]->call (*iw[i]);
436#endif
179 437
180 int timeout = (int) ((tw[0]->at - NOW) * 1000); 438#elif IOM_TIME
439 if (!to)
440 break;
181 441
182 int fds = poll (&pfs[0], pfs.size (), timeout); 442 select (0, 0, 0, 0, &to);
183
184 set_now (); 443 set_now ();
185 444#else
186 vector<io_watcher *>::iterator w; 445 break;
187 vector<pollfd>::iterator p; 446#endif
188
189 for (w = iow.begin (), p = pfs.begin ();
190 fds > 0 && w < iow.end ();
191 ++w, ++p)
192 if (p->revents)
193 {
194 --fds;
195 (*w)->call (**w, p->revents);
196 }
197 } 447 }
198} 448}
199 449
200void io_manager::idle_cb (time_watcher &w)
201{
202 w.at = NOW + 86400; // wake up every day, for no good reason
203}
204
205io_manager::io_manager ()
206{
207 iom_valid = true;
208
209 set_now ();
210 idle = new time_watcher (this, &io_manager::idle_cb);
211 idle->start (0);
212}
213
214io_manager::~io_manager ()
215{
216 iom_valid = false;
217}
218

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