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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 1.27 by pcg, Sun Dec 19 18:44:33 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
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 99tstamp io_manager::now ()
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 return (tstamp)tv.tv_sec + (tstamp)tv.tv_usec / 1000000.;
44 else
45 iom.reg (this);
46} 105}
47 106
107void io_manager::set_now ()
108{
109 NOW = now ();
110}
111#endif
112
113static bool iom_valid;
114
115// used for initialisation only
116static struct init {
117 init ()
118 {
119#if IOM_SIG
120 sigemptyset (&sigs);
121
122 if (pipe (sigpipe))
123 {
124 perror ("io_manager: unable to create signal pipe, aborting.");
125 abort ();
126 }
127
128 fcntl (sigpipe[0], F_SETFL, O_NONBLOCK); fcntl (sigpipe[0], F_SETFD, FD_CLOEXEC);
129 fcntl (sigpipe[1], F_SETFL, O_NONBLOCK); fcntl (sigpipe[1], F_SETFD, FD_CLOEXEC);
130#endif
131
132 iom_valid = true;
133
134#if IOM_TIME
135 io_manager::set_now ();
136
137 tw0.start (TSTAMP_MAX);
138#endif
139 }
140
141 static void required ();
142} init;
143
144void
145init::required ()
146{
147 if (!iom_valid)
148 {
149 write (2, "io_manager: early registration attempt, aborting.\n",
150 sizeof ("io_manager: early registration attempt, aborting.\n") - 1);
151 abort ();
152 }
153}
154
155template<class watcher>
156void io_manager::reg (watcher &w, io_manager_vec<watcher> &queue)
157{
158 init::required ();
159
160 if (!w.active)
161 {
162 queue.push_back (&w);
163 w.active = queue.size ();
164 }
165}
166
167template<class watcher>
168void io_manager::unreg (watcher &w, io_manager_vec<watcher> &queue)
169{
170 if (!iom_valid)
171 return;
172
173 if (w.active)
174 {
175 queue [w.active - 1] = 0;
176 w.active = 0;
177 }
178}
179
180#if IOM_TIME
48void time_watcher::trigger () 181void time_watcher::trigger ()
49{ 182{
50 call (at); 183 call (*this);
51 184 io_manager::reg (*this);
52 if (registered)
53 iom.reschedule_time_watchers ();
54 else
55 iom.reg (this);
56} 185}
57 186
58void time_watcher::start () 187void io_manager::reg (time_watcher &w) { io_manager::reg (w, tw); }
59{ 188void io_manager::unreg (time_watcher &w) { io_manager::unreg (w, tw); }
60 if (!registered) 189#endif
61 iom.reg (this);
62}
63 190
64void io_manager::reg (int fd, short events, io_watcher *w) 191#if IOM_IO
65{ 192void io_manager::reg (io_watcher &w) { io_manager::reg (w, iow); }
66 pollfd pfd; 193void io_manager::unreg (io_watcher &w) { io_manager::unreg (w, iow); }
194#endif
67 195
68 pfd.fd = fd; 196#if IOM_CHECK
69 pfd.events = events; 197void io_manager::reg (check_watcher &w) { io_manager::reg (w, cw); }
198void io_manager::unreg (check_watcher &w) { io_manager::unreg (w, cw); }
199#endif
70 200
71 pfs.push_back (pfd); 201#if IOM_IDLE
72 iow.push_back (w); 202void io_manager::reg (idle_watcher &w) { io_manager::reg (w, iw); }
73} 203void io_manager::unreg (idle_watcher &w) { io_manager::unreg (w, iw); }
204#endif
74 205
206#if IOM_SIG
207static void
208sighandler (int signum)
209{
210 sw [signum - 1]->pending = true;
211
212 // we use a pipe for signal notifications, as most current
213 // OSes (Linux...) do not implement pselect correctly. ugh.
214 char ch = signum; // actual content not used
215 write (sigpipe[1], &ch, 1);
216}
217
75void io_manager::unreg (const io_watcher *w) 218void io_manager::reg (sig_watcher &w)
76{ 219{
77 unsigned int sz = iow.size (); 220 assert (0 < w.signum);
78 unsigned int i = find (iow.begin (), iow.end (), w) - iow.begin ();
79 221
222 sw.reserve (w.signum);
223
224 while (sw.size () < w.signum) // pathetic
225 sw.push_back (0);
226
227 sig_vec *&sv = sw[w.signum - 1];
228
80 if (i != sz) 229 if (!sv)
81 { 230 {
82 if (sz == 1) 231 sv = new sig_vec;
232
233 sigaddset (&sigs, w.signum);
234 sigprocmask (SIG_BLOCK, &sigs, NULL);
235
236 struct sigaction sa;
237 sa.sa_handler = sighandler;
238 sigfillset (&sa.sa_mask);
239 sa.sa_flags = SA_RESTART;
240
241 if (sigaction (w.signum, &sa, 0))
83 { 242 {
243 perror ("io_manager: error while installing signal handler, ignoring.");
84 pfs.clear (); 244 abort ();
85 iow.clear ();
86 } 245 }
87 else if (i == sz - 1) 246
247 }
248
249 io_manager::reg (w, *sv);
250}
251
252void io_manager::unreg (sig_watcher &w)
253{
254 if (!w.active)
255 return;
256
257 assert (0 < w.signum && w.signum <= sw.size ());
258
259 io_manager::unreg (w, *sw[w.signum - 1]);
260}
261
262void sig_watcher::start (int signum)
263{
264 stop ();
265 this->signum = signum;
266 io_manager::reg (*this);
267}
268#endif
269
270void io_manager::loop ()
271{
272 init::required ();
273
274#if IOM_TIME
275 set_now ();
276#endif
277
278 for (;;)
279 {
280
281#if IOM_TIME
282 // call pending time watchers
283 {
284 bool activity;
285
286 do
287 {
288 activity = false;
289
290 for (int i = tw.size (); i--; )
291 if (!tw[i])
292 tw.erase_unordered (i);
293 else if (tw[i]->at <= NOW)
294 {
295 time_watcher &w = *tw[i];
296
297 unreg (w);
298 w.call (w);
299
300 activity = true;
301 }
302 }
303 while (activity);
304 }
305#endif
306
307#if IOM_CHECK
308 // call all check watchers
309 for (int i = cw.size (); i--; )
310 if (!cw[i])
311 cw.erase_unordered (i);
312 else
313 cw[i]->call (*cw[i]);
314#endif
315
316 struct TIMEVAL *to = 0;
317 struct TIMEVAL tval;
318
319#if IOM_IDLE
320 if (iw.size ())
88 { 321 {
89 iow.pop_back (); 322 tval.tv_sec = 0;
90 pfs.pop_back (); 323 tval.TV_FRAC = 0;
324 to = &tval;
91 } 325 }
92 else 326 else
327#endif
93 { 328 {
94 iow[i] = iow[sz - 1]; iow.pop_back (); 329#if IOM_TIME
95 pfs[i] = pfs[sz - 1]; pfs.pop_back (); 330 // find earliest active watcher
96 } 331 time_watcher *next = tw[0]; // the first time-watcher must exist at ALL times
97 }
98}
99 332
100void io_manager::reschedule_time_watchers () 333 for (io_manager_vec<time_watcher>::const_iterator i = tw.end (); i-- > tw.begin (); )
101{ 334 if (*i && (*i)->at < next->at)
102 make_heap (tw.begin (), tw.end (), lowest_first); 335 next = *i;
103}
104 336
105void io_manager::reg (time_watcher *w) 337 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 { 338 {
152 w->call (w->at); 339 double diff = next->at - NOW;
153 340 tval.tv_sec = (int)diff;
154 if (!w->registered) 341 tval.TV_FRAC = (int) ((diff - tval.tv_sec) * TV_MULT);
155 reg (w); 342 to = &tval;
156 } 343 }
157 } 344 }
345#endif
158 346
159 int timeout = (int) ((tw[0]->at - NOW) * 1000); 347#if IOM_IO || IOM_SIG
348 fd_set rfd, wfd;
160 349
161 int fds = poll (&pfs[0], pfs.size (), timeout); 350 FD_ZERO (&rfd);
351 FD_ZERO (&wfd);
162 352
353 int fds = 0;
354
355# if IOM_IO
356 for (io_manager_vec<io_watcher>::const_iterator i = iow.end (); i-- > iow.begin (); )
357 if (*i)
358 {
359 if ((*i)->events & EVENT_READ ) FD_SET ((*i)->fd, &rfd);
360 if ((*i)->events & EVENT_WRITE) FD_SET ((*i)->fd, &wfd);
361
362 if ((*i)->fd >= fds) fds = (*i)->fd + 1;
363 }
364# endif
365
366 if (!to && !fds) //TODO: also check idle_watchers and check_watchers?
367 break; // no events
368
369# if IOM_SIG
370 FD_SET (sigpipe[0], &rfd);
371 if (sigpipe[0] >= fds) fds = sigpipe[0] + 1;
372# endif
373
374# if IOM_SIG
375 // there is no race, as we use a pipe for signals, so select
376 // will return if a signal is caught.
377 sigprocmask (SIG_UNBLOCK, &sigs, NULL);
378# endif
379 fds = select (fds, &rfd, &wfd, NULL, to);
380# if IOM_SIG
381 sigprocmask (SIG_BLOCK, &sigs, NULL);
382# endif
383
384# if IOM_TIME
163 set_now (); 385 set_now ();
386# endif
164 387
165 for (unsigned int i = iow.size (); fds > 0 && i--; ) 388 if (fds > 0)
166 if (pfs[i].revents) 389 {
390# if IOM_SIG
391 if (FD_ISSET (sigpipe[0], &rfd))
167 { 392 {
168 --fds; 393 char ch;
169 iow[i]->call (pfs[i].revents); 394
395 while (read (sigpipe[0], &ch, 1) > 0)
396 ;
397
398 for (vector<sig_vec *>::iterator svp = sw.end (); svp-- > sw.begin (); )
399 if (*svp && (*svp)->pending)
400 {
401 sig_vec &sv = **svp;
402 for (int i = sv.size (); i--; )
403 if (!sv[i])
404 sv.erase_unordered (i);
405 else
406 sv[i]->call (*sv[i]);
407
408 sv.pending = false;
409 }
170 } 410 }
171 } 411# endif
172}
173 412
174void io_manager::idle_cb (tstamp &ts) 413# if IOM_IO
175{ 414 for (int i = iow.size (); i--; )
176 ts = NOW + 86400; // wake up every day, for no good reason 415 if (!iow[i])
177} 416 iow.erase_unordered (i);
417 else
418 {
419 io_watcher &w = *iow[i];
420 short revents = w.events;
178 421
179io_manager::io_manager () 422 if (!FD_ISSET (w.fd, &rfd)) revents &= ~EVENT_READ;
180{ 423 if (!FD_ISSET (w.fd, &wfd)) revents &= ~EVENT_WRITE;
424
425 if (revents)
426 w.call (w, revents);
427 }
428#endif
429 }
430 else if (fds < 0 && errno != EINTR)
431 {
432 perror ("io_manager: fatal error while waiting for I/O or time event, aborting.");
433 abort ();
434 }
435#if IOM_IDLE
436 else
437 for (int i = iw.size (); i--; )
438 if (!iw[i])
439 iw.erase_unordered (i);
440 else
441 iw[i]->call (*iw[i]);
442#endif
443
444#elif IOM_TIME
445 if (!to)
446 break;
447
448 select (0, 0, 0, 0, &to);
181 set_now (); 449 set_now ();
182 idle = new time_watcher (this, &io_manager::idle_cb); 450#else
183 idle->start (0); 451 break;
452#endif
453 }
184} 454}
185 455
186io_manager::~io_manager ()
187{
188 //
189}
190

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