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Comparing gvpe/src/iom.C (file contents):
Revision 1.6 by pcg, Fri Mar 28 04:05:10 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 at = when; 101 struct timeval tv;
41 102
42 if (registered) 103 gettimeofday (&tv, 0);
43 iom.reschedule_time_watchers (); 104 NOW = (tstamp)tv.tv_sec + (tstamp)tv.tv_usec / 1000000.;
44 else
45 iom.reg (this);
46} 105}
106#endif
47 107
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
48void time_watcher::trigger () 176void time_watcher::trigger ()
49{ 177{
50 call (at); 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
64void io_manager::reg (int fd, short events, io_watcher *w) 186#if IOM_IO
65{ 187void io_manager::reg (io_watcher &w) { io_manager::reg (w, iow); }
66 pollfd pfd; 188void io_manager::unreg (io_watcher &w) { io_manager::unreg (w, iow); }
189#endif
67 190
68 pfd.fd = fd; 191#if IOM_CHECK
69 pfd.events = events; 192void io_manager::reg (check_watcher &w) { io_manager::reg (w, cw); }
193void io_manager::unreg (check_watcher &w) { io_manager::unreg (w, cw); }
194#endif
70 195
71 pfs.push_back (pfd); 196#if IOM_IDLE
72 iow.push_back (w); 197void io_manager::reg (idle_watcher &w) { io_manager::reg (w, iw); }
73} 198void io_manager::unreg (idle_watcher &w) { io_manager::unreg (w, iw); }
199#endif
74 200
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
75void io_manager::unreg (const io_watcher *w) 213void io_manager::reg (sig_watcher &w)
76{ 214{
77 unsigned int sz = iow.size (); 215 assert (0 < w.signum);
78 unsigned int i = find (iow.begin (), iow.end (), w) - iow.begin ();
79 216
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
80 if (i != sz) 224 if (!sv)
81 { 225 {
82 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))
83 { 237 {
238 perror ("io_manager: error while installing signal handler, ignoring.");
84 pfs.clear (); 239 abort ();
85 iow.clear ();
86 } 240 }
87 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 ())
88 { 316 {
89 iow.pop_back (); 317 tval.tv_sec = 0;
90 pfs.pop_back (); 318 tval.TV_FRAC = 0;
319 to = &tval;
91 } 320 }
92 else 321 else
322#endif
93 { 323 {
94 iow[i] = iow[sz - 1]; iow.pop_back (); 324#if IOM_TIME
95 pfs[i] = pfs[sz - 1]; pfs.pop_back (); 325 // find earliest active watcher
96 } 326 time_watcher *next = tw[0]; // the first time-watcher must exist at ALL times
97 }
98}
99 327
100void io_manager::reschedule_time_watchers () 328 for (io_manager_vec<time_watcher>::const_iterator i = tw.end (); i-- > tw.begin (); )
101{ 329 if (*i && (*i)->at < next->at)
102 make_heap (tw.begin (), tw.end (), lowest_first); 330 next = *i;
103}
104 331
105void io_manager::reg (time_watcher *w) 332 if (next->at > NOW && next != tw[0])
106{
107 if (w->registered)
108 slog (L_CRIT, "FATAL: io_manager::reg(time_watcher) called on already-registered watcher");
109
110 tw.push_back (w);
111 push_heap (tw.begin (), tw.end (), lowest_first);
112}
113
114void io_manager::unreg (const time_watcher *w)
115{
116 unsigned int sz = tw.size ();
117 unsigned int i = find (tw.begin (), tw.end (), w) - tw.begin ();
118
119 if (i != sz)
120 {
121 if (i != sz - 1)
122 tw[i] = tw[sz - 1];
123
124 tw.pop_back ();
125 reschedule_time_watchers ();
126 }
127}
128
129inline void set_now (void)
130{
131 struct timeval tv;
132
133 gettimeofday (&tv, 0);
134
135 NOW = (tstamp)tv.tv_sec + (tstamp)tv.tv_usec / 1000000;
136}
137
138void io_manager::loop ()
139{
140 set_now ();
141
142 for (;;)
143 {
144 while (tw[0]->at <= NOW)
145 {
146 pop_heap (tw.begin (), tw.end (), lowest_first);
147 time_watcher *w = *(tw.end () - 1);
148 tw.pop_back ();
149
150 if (w->at >= 0)
151 { 333 {
152 w->call (w->at); 334 double diff = next->at - NOW;
153 335 tval.tv_sec = (int)diff;
154 if (!w->registered) 336 tval.TV_FRAC = (int) ((diff - tval.tv_sec) * TV_MULT);
155 reg (w); 337 to = &tval;
156 } 338 }
157 } 339 }
340#endif
158 341
159 int timeout = (int) ((tw[0]->at - NOW) * 1000); 342#if IOM_IO || IOM_SIG
343 fd_set rfd, wfd;
160 344
161 int fds = poll (&pfs[0], pfs.size (), timeout); 345 FD_ZERO (&rfd);
346 FD_ZERO (&wfd);
162 347
348 int fds = 0;
349
350# if IOM_IO
351 for (io_manager_vec<io_watcher>::const_iterator i = iow.end (); i-- > iow.begin (); )
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);
356
357 if ((*i)->fd >= fds) fds = (*i)->fd + 1;
358 }
359# endif
360
361 if (!to && !fds) //TODO: also check idle_watchers and check_watchers?
362 break; // no events
363
364# if IOM_SIG
365 FD_SET (sigpipe[0], &rfd);
366 if (sigpipe[0] >= fds) fds = sigpipe[0] + 1;
367# endif
368
369# if IOM_SIG
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
163 set_now (); 380 set_now ();
381# endif
164 382
165 for (unsigned int i = iow.size (); fds > 0 && i--; ) 383 if (fds > 0)
166 if (pfs[i].revents) 384 {
385# if IOM_SIG
386 if (FD_ISSET (sigpipe[0], &rfd))
167 { 387 {
168 --fds; 388 char ch;
169 iow[i]->call (pfs[i].revents); 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 }
170 } 405 }
171 } 406# endif
172}
173 407
174void io_manager::idle_cb (tstamp &ts) 408# if IOM_IO
175{ 409 for (int i = iow.size (); i--; )
176 ts = NOW + 86400; // wake up every day, for no good reason 410 if (!iow[i])
177} 411 iow.erase_unordered (i);
412 else
413 {
414 short revents = iow[i]->events;
178 415
179io_manager::io_manager () 416 if (!FD_ISSET (iow[i]->fd, &rfd)) revents &= ~EVENT_READ;
180{ 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);
434 else
435 iw[i]->call (*iw[i]);
436#endif
437
438#elif IOM_TIME
439 if (!to)
440 break;
441
442 select (0, 0, 0, 0, &to);
181 set_now (); 443 set_now ();
182 idle = new time_watcher (this, &io_manager::idle_cb); 444#else
183 idle->start (0); 445 break;
446#endif
447 }
184} 448}
185 449
186io_manager::~io_manager ()
187{
188 //
189}
190

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