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Comparing gvpe/src/iom.C (file contents):
Revision 1.20 by pcg, Fri Apr 2 14:42:45 2004 UTC vs.
Revision 1.31 by pcg, Mon Mar 7 01:31:26 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. 59 Temple Place, Suite 330, Boston, MA 02111-1307 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
… …
26#include <assert.h> 30#include <assert.h>
27 31
28#if 1 // older unices need these includes for select (2) 32#if 1 // older unices need these includes for select (2)
29# include <unistd.h> 33# include <unistd.h>
30# include <sys/types.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>
31#endif 42#endif
32 43
33// if the BSDs would at least be marginally POSIX-compatible.. *sigh* 44// if the BSDs would at least be marginally POSIX-compatible.. *sigh*
34// until that happens, sys/select.h must come last 45// until that happens, sys/select.h must come last
35#include <sys/select.h> 46#include <sys/select.h>
36 47
37// for IOM_SIG 48#define TIMEVAL timeval
38#include <signal.h> 49#define TV_FRAC tv_usec
50#define TV_MULT 1000000L
39 51
40#include "iom.h" 52#if IOM_IO
41 53static io_manager_vec<io_watcher> iow;
42// TSTAMP_MAX must still fit into a positive struct timeval 54#endif
43#define TSTAMP_MAX (double)(1UL<<31) 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
44 75
45// this is a dummy time watcher to ensure that the first 76// this is a dummy time watcher to ensure that the first
46// time watcher is _always_ valid, this gets rid of a lot 77// time watcher is _always_ valid, this gets rid of a lot
47// of null-pointer-checks 78// of null-pointer-checks
48// (must come _before_ iom is being defined) 79// (must come _before_ iom is being defined)
… …
50 { 81 {
51 void cb (time_watcher &w) 82 void cb (time_watcher &w)
52 { 83 {
53 // should never get called 84 // should never get called
54 // reached end-of-time, or tstamp has a bogus definition, 85 // reached end-of-time, or tstamp has a bogus definition,
55 // or compiler initilization order broken, or somethine else :) 86 // or compiler initialisation order broken, or something else :)
56 abort (); 87 abort ();
57 } 88 }
58 89
59 tw0 () 90 tw0 ()
60 : time_watcher (this, &tw0::cb) 91 : time_watcher (this, &tw0::cb)
61 { } 92 { }
62 } tw0; 93 } tw0;
63 94
64tstamp 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
65static bool iom_valid; 112static bool iom_valid;
66io_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}
67 153
68template<class watcher> 154template<class watcher>
69void io_manager::reg (watcher *w, io_manager_vec<watcher> &queue) 155void io_manager::reg (watcher &w, io_manager_vec<watcher> &queue)
70{ 156{
71 if (!iom_valid) 157 init::required ();
72 abort ();
73 158
74 if (!w->active) 159 if (!w.active)
75 { 160 {
76#if IOM_CHECK
77 queue.activity = true;
78#endif
79 queue.push_back (w); 161 queue.push_back (&w);
80 w->active = queue.size (); 162 w.active = queue.size ();
81 } 163 }
82} 164}
83 165
84template<class watcher> 166template<class watcher>
85void io_manager::unreg (watcher *w, io_manager_vec<watcher> &queue) 167void io_manager::unreg (watcher &w, io_manager_vec<watcher> &queue)
86{ 168{
87 if (!iom_valid) 169 if (!iom_valid)
88 return; 170 return;
89 171
90 if (w->active) 172 if (w.active)
91 { 173 {
92 queue [w->active - 1] = 0; 174 queue [w.active - 1] = 0;
93 w->active = 0; 175 w.active = 0;
94 } 176 }
95} 177}
96 178
97#if IOM_TIME 179#if IOM_TIME
98void time_watcher::trigger () 180void time_watcher::trigger ()
99{ 181{
100 call (*this); 182 call (*this);
101 183 io_manager::reg (*this);
102 iom.reg (this);
103} 184}
104 185
105void io_manager::reg (time_watcher *w) { reg (w, tw); } 186void io_manager::reg (time_watcher &w) { io_manager::reg (w, tw); }
106void io_manager::unreg (time_watcher *w) { unreg (w, tw); } 187void io_manager::unreg (time_watcher &w) { io_manager::unreg (w, tw); }
107#endif 188#endif
108 189
109#if IOM_IO 190#if IOM_IO
110void io_manager::reg (io_watcher *w) { reg (w, iow); } 191void io_manager::reg (io_watcher &w) { io_manager::reg (w, iow); }
111void io_manager::unreg (io_watcher *w) { unreg (w, iow); } 192void io_manager::unreg (io_watcher &w) { io_manager::unreg (w, iow); }
112#endif 193#endif
113 194
114#if IOM_CHECK 195#if IOM_CHECK
115void io_manager::reg (check_watcher *w) { reg (w, cw); } 196void io_manager::reg (check_watcher &w) { io_manager::reg (w, cw); }
116void io_manager::unreg (check_watcher *w) { unreg (w, cw); } 197void io_manager::unreg (check_watcher &w) { io_manager::unreg (w, cw); }
117#endif 198#endif
118 199
119#if IOM_IDLE 200#if IOM_IDLE
120void io_manager::reg (idle_watcher *w) { reg (w, iw); } 201void io_manager::reg (idle_watcher &w) { io_manager::reg (w, iw); }
121void io_manager::unreg (idle_watcher *w) { unreg (w, iw); } 202void io_manager::unreg (idle_watcher &w) { io_manager::unreg (w, iw); }
122#endif
123
124#if IOM_TIME
125inline void set_now (void)
126{
127 struct timeval tv;
128
129 gettimeofday (&tv, 0);
130
131 NOW = (tstamp)tv.tv_sec + (tstamp)tv.tv_usec / 1000000;
132}
133#endif 203#endif
134 204
135#if IOM_SIG 205#if IOM_SIG
136// race conditions galore 206static void
137 207sighandler (int signum)
138void io_manager::sighandler (int signum)
139{ 208{
140 assert (0 < signum && signum <= iom.sw.size ()); 209 sw [signum - 1]->pending = true;
141 210
142 sig_vec &sv = *iom.sw [signum - 1]; 211 // we use a pipe for signal notifications, as most current
143 212 // OSes (Linux...) do not implement pselect correctly. ugh.
144 for (int i = sv.size (); i--; ) 213 char ch = signum; // actual content not used
145 if (!sv[i]) 214 write (sigpipe[1], &ch, 1);
146 sv.erase_unordered (i);
147 else
148 sv[i]->call (*sv[i]);
149} 215}
150 216
151void io_manager::reg (sig_watcher *w) 217void io_manager::reg (sig_watcher &w)
152{ 218{
153 assert (0 < w->signum); 219 assert (0 < w.signum);
154 220
155 sw.reserve (w->signum); 221 sw.reserve (w.signum);
156 222
223 while (sw.size () < w.signum) // pathetic
224 sw.push_back (0);
225
157 sig_vec *&sv = sw [w->signum - 1]; 226 sig_vec *&sv = sw[w.signum - 1];
158 227
159 if (!sv) 228 if (!sv)
160 { 229 {
161 sv = new sig_vec; 230 sv = new sig_vec;
162 231
232 sigaddset (&sigs, w.signum);
233 sigprocmask (SIG_BLOCK, &sigs, NULL);
234
163 struct sigaction sa; 235 struct sigaction sa;
164 sa.sa_handler = io_manager::sighandler; 236 sa.sa_handler = sighandler;
165 sigfillset (&sa.sa_mask); 237 sigfillset (&sa.sa_mask);
166 sa.sa_flags = 0; 238 sa.sa_flags = SA_RESTART;
167 239
168 if (sigaction (w->signum, &sa, 0)) 240 if (sigaction (w.signum, &sa, 0))
169 { 241 {
170 perror ("Error while installing signal handler"); 242 perror ("io_manager: error while installing signal handler, ignoring.");
171 abort (); 243 abort ();
172 } 244 }
173 }
174 245
175 reg (w, *sv); 246 }
176}
177 247
248 io_manager::reg (w, *sv);
249}
250
178void io_manager::unreg (sig_watcher *w) 251void io_manager::unreg (sig_watcher &w)
179{ 252{
253 if (!w.active)
254 return;
255
180 assert (0 < w->signum && w->signum <= sw.size ()); 256 assert (0 < w.signum && w.signum <= sw.size ());
181 257
182 unreg (w, *sw [w->signum - 1]); 258 io_manager::unreg (w, *sw[w.signum - 1]);
183} 259}
184 260
185void sig_watcher::start (int signum) 261void sig_watcher::start (int signum)
186{ 262{
187 stop (); 263 stop ();
188 this->signum = signum; 264 this->signum = signum;
189 iom.reg (this); 265 io_manager::reg (*this);
190} 266}
191#endif 267#endif
192 268
193void io_manager::loop () 269void io_manager::loop ()
194{ 270{
271 init::required ();
272
195#if IOM_TIME 273#if IOM_TIME
196 set_now (); 274 set_now ();
197#endif 275#endif
198 276
199 for (;;) 277 for (;;)
200 { 278 {
201 struct timeval *to = 0;
202 struct timeval tval;
203 279
204#if IOM_IDLE 280#if IOM_TIME
205 if (iw.size ()) 281 // call pending time watchers
206 { 282 {
207 tval.tv_sec = 0; 283 bool activity;
208 tval.tv_usec = 0; 284
209 to = &tval;
210 } 285 do
211 else
212#endif
213
214 {
215#if IOM_TIME
216 time_watcher *next;
217
218 for (;;)
219 { 286 {
220 next = tw[0]; // the first time-watcher must exist at ALL times 287 activity = false;
221 288
222 for (int i = tw.size (); i--; ) 289 for (int i = tw.size (); i--; )
223 if (!tw[i]) 290 if (!tw[i])
224 tw.erase_unordered (i); 291 tw.erase_unordered (i);
225 else if (tw[i]->at < next->at) 292 else if (tw[i]->at <= NOW)
226 next = tw[i];
227
228 if (next->at > NOW)
229 { 293 {
230 if (next != tw[0]) 294 time_watcher &w = *tw[i];
231 { 295
232 double diff = next->at - NOW;
233 tval.tv_sec = (int)diff;
234 tval.tv_usec = (int) ((diff - tval.tv_sec) * 1000000);
235 to = &tval;
236 }
237 break; 296 unreg (w);
297 w.call (w);
298
299 activity = true;
238 } 300 }
239 else
240 {
241 unreg (next);
242 next->call (*next);
243 }
244 } 301 }
245#endif 302 while (activity);
246
247 } 303 }
304#endif
248 305
249#if IOM_CHECK 306#if IOM_CHECK
250 tw.activity = false; 307 // call all check watchers
251
252 for (int i = cw.size (); i--; ) 308 for (int i = cw.size (); i--; )
253 if (!cw[i]) 309 if (!cw[i])
254 cw.erase_unordered (i); 310 cw.erase_unordered (i);
255 else 311 else
256 cw[i]->call (*cw[i]); 312 cw[i]->call (*cw[i]);
313#endif
257 314
258 if (tw.activity) 315 struct TIMEVAL *to = 0;
316 struct TIMEVAL tval;
317
318#if IOM_IDLE
319 if (iw.size ())
259 { 320 {
260 tval.tv_sec = 0; 321 tval.tv_sec = 0;
261 tval.tv_usec = 0; 322 tval.TV_FRAC = 0;
262 to = &tval; 323 to = &tval;
263 } 324 }
325 else
264#endif 326#endif
265 327 {
266#if IOM_IO 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
267 fd_set rfd, wfd; 347 fd_set rfd, wfd;
268 348
269 FD_ZERO (&rfd); 349 FD_ZERO (&rfd);
270 FD_ZERO (&wfd); 350 FD_ZERO (&wfd);
271 351
272 int fds = 0; 352 int fds = 0;
273 353
354# if IOM_IO
274 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 (); )
275 if (*i) 356 if (*i)
276 { 357 {
277 if ((*i)->events & EVENT_READ ) FD_SET ((*i)->fd, &rfd); 358 if ((*i)->events & EVENT_READ ) FD_SET ((*i)->fd, &rfd);
278 if ((*i)->events & EVENT_WRITE) FD_SET ((*i)->fd, &wfd); 359 if ((*i)->events & EVENT_WRITE) FD_SET ((*i)->fd, &wfd);
279 360
280 if ((*i)->fd >= fds) fds = (*i)->fd + 1; 361 if ((*i)->fd >= fds) fds = (*i)->fd + 1;
281 } 362 }
363# endif
282 364
283 if (!to && !fds) //TODO: also check idle_watchers and check_watchers 365 if (!to && !fds) //TODO: also check idle_watchers and check_watchers?
284 break; // no events 366 break; // no events
285 367
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
286 fds = select (fds, &rfd, &wfd, NULL, to); 378 fds = select (fds, &rfd, &wfd, NULL, to);
379# if IOM_SIG
380 sigprocmask (SIG_BLOCK, &sigs, NULL);
381# endif
382
287# if IOM_TIME 383# if IOM_TIME
384 {
385 // update time, try to compensate for gross non-monotonic time changes
386 tstamp diff = NOW;
288 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 }
289# endif 395# endif
290 396
291 if (fds > 0) 397 if (fds > 0)
292 for (int i = iow.size (); i--; ) 398 {
293 if (!iow[i]) 399# if IOM_SIG
294 iow.erase_unordered (i); 400 if (FD_ISSET (sigpipe[0], &rfd))
295 else
296 { 401 {
297 short revents = iow[i]->events; 402 char ch;
298 403
299 if (!FD_ISSET (iow[i]->fd, &rfd)) revents &= ~EVENT_READ; 404 while (read (sigpipe[0], &ch, 1) > 0)
300 if (!FD_ISSET (iow[i]->fd, &wfd)) revents &= ~EVENT_WRITE; 405 ;
301 406
302 if (revents) 407 for (vector<sig_vec *>::iterator svp = sw.end (); svp-- > sw.begin (); )
303 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 }
304 } 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 }
305 else if (fds < 0 && errno != EINTR) 439 else if (fds < 0 && errno != EINTR)
306 { 440 {
307 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.");
308 abort (); 442 abort ();
309 } 443 }
310#if IOM_IDLE 444#if IOM_IDLE
311 else 445 else
312 for (int i = iw.size (); i--; ) 446 for (int i = iw.size (); i--; )
… …
323 select (0, 0, 0, 0, &to); 457 select (0, 0, 0, 0, &to);
324 set_now (); 458 set_now ();
325#else 459#else
326 break; 460 break;
327#endif 461#endif
328
329 } 462 }
330} 463}
331 464
332io_manager::io_manager ()
333{
334 iom_valid = true;
335
336#if IOM_TIME
337 set_now ();
338
339 tw0.start (TSTAMP_MAX);
340#endif
341}
342
343io_manager::~io_manager ()
344{
345 iom_valid = false;
346}
347

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