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Comparing gvpe/src/iom.C (file contents):
Revision 1.13 by pcg, Sat Jan 17 01:18:36 2004 UTC vs.
Revision 1.32 by pcg, Tue Apr 26 00:55:56 2005 UTC

1/* 1/*
2 iom.C -- generic I/O multiplexor 2 iom.C -- generic I/O multiplexer
3 Copyright (C) 2003, 2004 Marc Lehmann <pcg@goof.com> 3 Copyright (C) 2003, 2004 Marc Lehmann <gvpe@schmorp.de>
4 4
5 This file is part of GVPE.
6
5 This program is free software; you can redistribute it and/or modify 7 GVPE is free software; you can redistribute it and/or modify
6 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
7 the Free Software Foundation; either version 2 of the License, or 9 the Free Software Foundation; either version 2 of the License, or
8 (at your option) any later version. 10 (at your option) any later version.
9 11
10 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,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of 13 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU General Public License for more details. 15 GNU General Public License for more details.
14 16
15 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
16 along with this program; if not, write to the Free Software 18 along with gvpe; if not, write to the Free Software
17 Foundation, Inc. 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 19 Foundation, Inc. 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
18*/ 20*/
21
22#include "iom.h"
19 23
20#include <cstdio> 24#include <cstdio>
21#include <cstdlib> 25#include <cstdlib>
22#include <cerrno> 26#include <cerrno>
23 27
28#include <sys/time.h>
29
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
40# include <csignal>
41# include <fcntl.h>
42#endif
43
44// if the BSDs would at least be marginally POSIX-compatible.. *sigh*
45// until that happens, sys/select.h must come last
24#include <sys/select.h> 46#include <sys/select.h>
25#include <sys/time.h>
26 47
27#include "iom.h" 48#define TIMEVAL timeval
49#define TV_FRAC tv_usec
50#define TV_MULT 1000000L
28 51
29// TSTAMP_MAX must still fit into a positive struct timeval 52#if IOM_IO
30#define TSTAMP_MAX (double)(1UL<<31) 53static io_manager_vec<io_watcher> iow;
54#endif
55#if IOM_CHECK
56static io_manager_vec<check_watcher> cw;
57#endif
58#if IOM_TIME
59static io_manager_vec<time_watcher> tw;
60#endif
61#if IOM_IDLE
62static io_manager_vec<idle_watcher> iw;
63#endif
64#if IOM_SIG
65static int sigpipe[2]; // signal signalling pipe
66static sigset_t sigs;
67struct sig_vec : io_manager_vec<sig_watcher> {
68 int pending;
69 sig_vec ()
70 : pending (false)
71 { }
72};
73static vector<sig_vec *> sw;
74#endif
75
76// this is a dummy time watcher to ensure that the first
77// time watcher is _always_ valid, this gets rid of a lot
78// of null-pointer-checks
79// (must come _before_ iom is being defined)
80static struct tw0 : time_watcher
81 {
82 void cb (time_watcher &w)
83 {
84 // should never get called
85 // reached end-of-time, or tstamp has a bogus definition,
86 // or compiler initialisation order broken, or something else :)
87 abort ();
88 }
89
90 tw0 ()
91 : time_watcher (this, &tw0::cb)
92 { }
93 } tw0;
31 94
32tstamp NOW; 95tstamp NOW;
96
97#if IOM_TIME
98tstamp io_manager::now ()
99{
100 struct timeval tv;
101
102 gettimeofday (&tv, 0);
103 return (tstamp)tv.tv_sec + (tstamp)tv.tv_usec / 1000000.;
104}
105
106void io_manager::set_now ()
107{
108 NOW = now ();
109}
110#endif
111
33static bool iom_valid; 112static bool iom_valid;
34io_manager iom; 113
114// used for initialisation only
115static struct init {
116 init ()
117 {
118#if IOM_SIG
119 sigemptyset (&sigs);
120
121 if (pipe (sigpipe))
122 {
123 perror ("io_manager: unable to create signal pipe, aborting.");
124 abort ();
125 }
126
127 fcntl (sigpipe[0], F_SETFL, O_NONBLOCK); fcntl (sigpipe[0], F_SETFD, FD_CLOEXEC);
128 fcntl (sigpipe[1], F_SETFL, O_NONBLOCK); fcntl (sigpipe[1], F_SETFD, FD_CLOEXEC);
129#endif
130
131 iom_valid = true;
132
133#if IOM_TIME
134 io_manager::set_now ();
135
136 tw0.start (TSTAMP_MAX);
137#endif
138 }
139
140 static void required ();
141} init;
142
143void
144init::required ()
145{
146 if (!iom_valid)
147 {
148 write (2, "io_manager: early registration attempt, aborting.\n",
149 sizeof ("io_manager: early registration attempt, aborting.\n") - 1);
150 abort ();
151 }
152}
35 153
36template<class watcher> 154template<class watcher>
37void io_manager::reg (watcher *w, io_manager_vec<watcher> &queue) 155void io_manager::reg (watcher &w, io_manager_vec<watcher> &queue)
38{ 156{
39 if (!iom_valid) 157 init::required ();
40 abort ();
41 158
42 if (!w->active) 159 if (!w.active)
43 { 160 {
44 queue.push_back (w); 161 queue.push_back (&w);
45 w->active = queue.size (); 162 w.active = queue.size ();
46 } 163 }
47} 164}
48 165
49template<class watcher> 166template<class watcher>
50void io_manager::unreg (watcher *w, io_manager_vec<watcher> &queue) 167void io_manager::unreg (watcher &w, io_manager_vec<watcher> &queue)
51{ 168{
52 if (!iom_valid) 169 if (!iom_valid)
53 return; 170 return;
54 171
55 if (w->active) 172 if (w.active)
56 { 173 {
57 queue [w->active - 1] = 0; 174 queue [w.active - 1] = 0;
58 w->active = 0; 175 w.active = 0;
59 } 176 }
60} 177}
61 178
62#if IOM_TIME 179#if IOM_TIME
63void time_watcher::trigger () 180void time_watcher::trigger ()
64{ 181{
65 call (*this); 182 call (*this);
66 183 io_manager::reg (*this);
67 iom.reg (this);
68} 184}
69 185
70void io_manager::reg (time_watcher *w) { reg (w, tw); } 186void io_manager::reg (time_watcher &w) { io_manager::reg (w, tw); }
71void io_manager::unreg (time_watcher *w) { unreg (w, tw); } 187void io_manager::unreg (time_watcher &w) { io_manager::unreg (w, tw); }
72#endif 188#endif
73 189
74#if IOM_IO 190#if IOM_IO
75void io_manager::reg (io_watcher *w) { reg (w, iow); } 191void io_manager::reg (io_watcher &w) { io_manager::reg (w, iow); }
76void io_manager::unreg (io_watcher *w) { unreg (w, iow); } 192void io_manager::unreg (io_watcher &w) { io_manager::unreg (w, iow); }
77#endif 193#endif
78 194
79#if IOM_CHECK 195#if IOM_CHECK
80void io_manager::reg (check_watcher *w) { reg (w, cw); } 196void io_manager::reg (check_watcher &w) { io_manager::reg (w, cw); }
81void io_manager::unreg (check_watcher *w) { unreg (w, cw); } 197void io_manager::unreg (check_watcher &w) { io_manager::unreg (w, cw); }
82#endif 198#endif
83 199
84#if IOM_IDLE 200#if IOM_IDLE
85void io_manager::reg (idle_watcher *w) { reg (w, iw); } 201void io_manager::reg (idle_watcher &w) { io_manager::reg (w, iw); }
86void io_manager::unreg (idle_watcher *w) { unreg (w, iw); } 202void io_manager::unreg (idle_watcher &w) { io_manager::unreg (w, iw); }
87#endif 203#endif
88 204
89#if IOM_TIME 205#if IOM_SIG
90inline void set_now (void) 206static void
207sighandler (int signum)
91{ 208{
92 struct timeval tv; 209 sw [signum - 1]->pending = true;
93 210
94 gettimeofday (&tv, 0); 211 // we use a pipe for signal notifications, as most current
95 212 // OSes (Linux...) do not implement pselect correctly. ugh.
96 NOW = (tstamp)tv.tv_sec + (tstamp)tv.tv_usec / 1000000; 213 char ch = signum; // actual content not used
97#endif 214 write (sigpipe[1], &ch, 1);
98} 215}
216
217void io_manager::reg (sig_watcher &w)
218{
219 assert (0 < w.signum);
220
221 sw.reserve (w.signum);
222
223 while (sw.size () < w.signum) // pathetic
224 sw.push_back (0);
225
226 sig_vec *&sv = sw[w.signum - 1];
227
228 if (!sv)
229 {
230 sv = new sig_vec;
231
232 sigaddset (&sigs, w.signum);
233 sigprocmask (SIG_BLOCK, &sigs, NULL);
234
235 struct sigaction sa;
236 sa.sa_handler = sighandler;
237 sigfillset (&sa.sa_mask);
238 sa.sa_flags = SA_RESTART;
239
240 if (sigaction (w.signum, &sa, 0))
241 {
242 perror ("io_manager: error while installing signal handler, ignoring.");
243 abort ();
244 }
245
246 }
247
248 io_manager::reg (w, *sv);
249}
250
251void io_manager::unreg (sig_watcher &w)
252{
253 if (!w.active)
254 return;
255
256 assert (0 < w.signum && w.signum <= sw.size ());
257
258 io_manager::unreg (w, *sw[w.signum - 1]);
259}
260
261void sig_watcher::start (int signum)
262{
263 stop ();
264 this->signum = signum;
265 io_manager::reg (*this);
266}
267#endif
99 268
100void io_manager::loop () 269void io_manager::loop ()
101{ 270{
271 init::required ();
272
102#if IOM_TIME 273#if IOM_TIME
103 set_now (); 274 set_now ();
104#endif 275#endif
105 276
106 for (;;) 277 for (;;)
107 { 278 {
108 struct timeval *to = 0;
109 struct timeval tval;
110 279
111#if IOM_IDLE 280#if IOM_TIME
112 if (iw.size ()) 281 // call pending time watchers
113 { 282 {
114 tval.tv_sec = 0; 283 bool activity;
115 tval.tv_usec = 0; 284
116 to = &tval;
117 } 285 do
118 else
119#endif
120 {
121#if IOM_TIME
122 time_watcher *next;
123
124 for (;;)
125 { 286 {
126 next = tw[0]; // the first time-watcher must exist at ALL times 287 activity = false;
127 288
128 for (int i = tw.size (); i--; ) 289 for (int i = tw.size (); i--; )
129 if (!tw[i]) 290 if (!tw[i])
130 tw.erase_unordered (i); 291 tw.erase_unordered (i);
131 else if (tw[i]->at < next->at) 292 else if (tw[i]->at <= NOW)
132 next = tw[i];
133
134 if (next->at > NOW)
135 { 293 {
136 if (next != tw[0]) 294 time_watcher &w = *tw[i];
137 { 295
138 double diff = next->at - NOW;
139 tval.tv_sec = (int)diff;
140 tval.tv_usec = (int)((diff - tval.tv_sec) * 1000000);
141 to = &tval;
142 }
143 break; 296 unreg (w);
297 w.call (w);
298
299 activity = true;
144 } 300 }
145 else
146 {
147 unreg (next);
148 next->call (*next);
149 }
150 } 301 }
151#endif 302 while (activity);
152 } 303 }
304#endif
153 305
154#if IOM_CHECK 306#if IOM_CHECK
307 // call all check watchers
155 for (int i = cw.size (); i--; ) 308 for (int i = cw.size (); i--; )
156 if (!cw[i]) 309 if (!cw[i])
157 cw.erase_unordered (i); 310 cw.erase_unordered (i);
158 else 311 else
159 cw[i]->call (*cw[i]); 312 cw[i]->call (*cw[i]);
160#endif 313#endif
161 314
315 struct TIMEVAL *to = 0;
316 struct TIMEVAL tval;
317
162#if IOM_IO 318#if IOM_IDLE
319 if (iw.size ())
320 {
321 tval.tv_sec = 0;
322 tval.TV_FRAC = 0;
323 to = &tval;
324 }
325 else
326#endif
327 {
328#if IOM_TIME
329 // find earliest active watcher
330 time_watcher *next = tw[0]; // the first time-watcher must exist at ALL times
331
332 for (io_manager_vec<time_watcher>::const_iterator i = tw.end (); i-- > tw.begin (); )
333 if (*i && (*i)->at < next->at)
334 next = *i;
335
336 if (next->at > NOW && next != tw[0])
337 {
338 double diff = next->at - NOW;
339 tval.tv_sec = (int)diff;
340 tval.TV_FRAC = (int) ((diff - tval.tv_sec) * TV_MULT);
341 to = &tval;
342 }
343 }
344#endif
345
346#if IOM_IO || IOM_SIG
163 fd_set rfd, wfd, efd; 347 fd_set rfd, wfd;
164 348
165 FD_ZERO (&rfd); 349 FD_ZERO (&rfd);
166 FD_ZERO (&wfd); 350 FD_ZERO (&wfd);
167 351
168 int fds = 0; 352 int fds = 0;
169 353
354# if IOM_IO
170 for (io_manager_vec<io_watcher>::iterator i = iow.end (); i-- > iow.begin (); ) 355 for (io_manager_vec<io_watcher>::const_iterator i = iow.end (); i-- > iow.begin (); )
171 if (*i) 356 if (*i)
172 { 357 {
173 if ((*i)->events & EVENT_READ ) FD_SET ((*i)->fd, &rfd); 358 if ((*i)->events & EVENT_READ ) FD_SET ((*i)->fd, &rfd);
174 if ((*i)->events & EVENT_WRITE) FD_SET ((*i)->fd, &wfd); 359 if ((*i)->events & EVENT_WRITE) FD_SET ((*i)->fd, &wfd);
175 360
176 if ((*i)->fd >= fds) fds = (*i)->fd + 1; 361 if ((*i)->fd >= fds) fds = (*i)->fd + 1;
177 } 362 }
363# endif
178 364
179 if (!to && !fds) //TODO: also check idle_watchers and check_watchers 365 if (!to && !fds) //TODO: also check idle_watchers and check_watchers?
180 break; // no events 366 break; // no events
181 367
368# if IOM_SIG
369 FD_SET (sigpipe[0], &rfd);
370 if (sigpipe[0] >= fds) fds = sigpipe[0] + 1;
371# endif
372
373# if IOM_SIG
374 // there is no race, as we use a pipe for signals, so select
375 // will return if a signal is caught.
376 sigprocmask (SIG_UNBLOCK, &sigs, NULL);
377# endif
182 fds = select (fds, &rfd, &wfd, &efd, to); 378 fds = select (fds, &rfd, &wfd, NULL, to);
379# if IOM_SIG
380 sigprocmask (SIG_BLOCK, &sigs, NULL);
381# endif
382
183# if IOM_TIME 383# if IOM_TIME
384 {
385 // update time, try to compensate for gross non-monotonic time changes
386 tstamp diff = NOW;
184 set_now (); 387 set_now ();
388 diff = NOW - diff;
389
390 if (diff < 0)
391 for (io_manager_vec<time_watcher>::const_iterator i = tw.end (); i-- > tw.begin (); )
392 if (*i)
393 (*i)->at += diff;
394 }
185# endif 395# endif
186 396
187 if (fds > 0) 397 if (fds > 0)
188 for (int i = iow.size (); i--; ) 398 {
189 if (!iow[i]) 399# if IOM_SIG
190 iow.erase_unordered (i); 400 if (FD_ISSET (sigpipe[0], &rfd))
191 else
192 { 401 {
193 short revents = iow[i]->events; 402 char ch;
194 403
195 if (!FD_ISSET (iow[i]->fd, &rfd)) revents &= ~EVENT_READ; 404 while (read (sigpipe[0], &ch, 1) > 0)
196 if (!FD_ISSET (iow[i]->fd, &wfd)) revents &= ~EVENT_WRITE; 405 ;
197 406
198 if (revents) 407 for (vector<sig_vec *>::iterator svp = sw.end (); svp-- > sw.begin (); )
199 iow[i]->call (*iow[i], revents); 408 if (*svp && (*svp)->pending)
409 {
410 sig_vec &sv = **svp;
411 for (int i = sv.size (); i--; )
412 if (!sv[i])
413 sv.erase_unordered (i);
414 else
415 sv[i]->call (*sv[i]);
416
417 sv.pending = false;
418 }
200 } 419 }
420# endif
421
422# if IOM_IO
423 for (int i = iow.size (); i--; )
424 if (!iow[i])
425 iow.erase_unordered (i);
426 else
427 {
428 io_watcher &w = *iow[i];
429 short revents = w.events;
430
431 if (!FD_ISSET (w.fd, &rfd)) revents &= ~EVENT_READ;
432 if (!FD_ISSET (w.fd, &wfd)) revents &= ~EVENT_WRITE;
433
434 if (revents)
435 w.call (w, revents);
436 }
437#endif
438 }
201 else if (fds < 0 && errno != EINTR) 439 else if (fds < 0 && errno != EINTR)
202 { 440 {
203 perror ("Error while waiting for I/O or time event"); 441 perror ("io_manager: fatal error while waiting for I/O or time event, aborting.");
204 abort (); 442 abort ();
205 } 443 }
206#if IOM_IDLE 444#if IOM_IDLE
207 else 445 else
208 for (int i = iw.size (); i--; ) 446 for (int i = iw.size (); i--; )
… …
222 break; 460 break;
223#endif 461#endif
224 } 462 }
225} 463}
226 464
227// this is a dummy time watcher to ensure that the first
228// time watcher is _always_ valid, this gets rid of a lot
229// of null-pointer-checks
230static struct tw0 : time_watcher {
231 void cb (time_watcher &w)
232 {
233 // should never get called
234 // reached end-of-time, or tstamp has a bogus definition :)
235 abort ();
236 }
237
238 tw0()
239 : time_watcher (this, &tw0::cb)
240 { }
241} tw0;
242
243io_manager::io_manager ()
244{
245 iom_valid = true;
246
247#if IOM_TIME
248 set_now ();
249
250 tw0.start (TSTAMP_MAX);
251#endif
252}
253
254io_manager::~io_manager ()
255{
256 iom_valid = false;
257}
258

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