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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 1.36 by pcg, Thu Dec 14 03:18:53 2006 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) 2003-2006 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>
27#include <cassert>
23 28
29#include <sys/types.h>
24#include <sys/time.h> 30#include <sys/time.h>
25
26#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>
34# include <time.h>
35#endif
36
37#if IOM_CHILD
30# include <sys/types.h> 38# include <sys/wait.h>
39#endif
40
41#if IOM_SIG
42# include <csignal>
43# include <fcntl.h>
31#endif 44#endif
32 45
33// if the BSDs would at least be marginally POSIX-compatible.. *sigh* 46// if the BSDs would at least be marginally POSIX-compatible.. *sigh*
34// until that happens, sys/select.h must come last 47// until that happens, sys/select.h must come last
35#include <sys/select.h> 48#include <sys/select.h>
36 49
37// for IOM_SIG 50#define TIMEVAL timeval
38#include <signal.h> 51#define TV_FRAC tv_usec
52#define TV_MULT 1000000L
39 53
40#include "iom.h" 54#if IOM_IO
41 55static io_manager_vec<io_watcher> iow;
42// TSTAMP_MAX must still fit into a positive struct timeval 56#endif
43#define TSTAMP_MAX (double)(1UL<<31) 57#if IOM_CHECK
58static io_manager_vec<check_watcher> cw;
59#endif
60#if IOM_TIME
61static io_manager_vec<time_watcher> tw;
62#endif
63#if IOM_IDLE
64static io_manager_vec<idle_watcher> iw;
65#endif
66#if IOM_SIG
67static int sigpipe[2]; // signal signalling pipe
68static sigset_t sigs;
69struct sig_vec : io_manager_vec<sig_watcher> {
70 int pending;
71 sig_vec ()
72 : pending (false)
73 { }
74};
75static vector<sig_vec *> sw;
76#endif
77#if IOM_CHILD
78static io_manager_vec<child_watcher> pw;
79#endif
44 80
45// this is a dummy time watcher to ensure that the first 81// this is a dummy time watcher to ensure that the first
46// time watcher is _always_ valid, this gets rid of a lot 82// time watcher is _always_ valid, this gets rid of a lot
47// of null-pointer-checks 83// of null-pointer-checks
48// (must come _before_ iom is being defined) 84// (must come _before_ iom is being defined)
49static struct tw0 : time_watcher 85static struct tw0 : time_watcher
86{
87 void cb (time_watcher &w)
50 { 88 {
89 // should never get called
90 // reached end-of-time, or tstamp has a bogus definition,
91 // or compiler initialisation order broken, or something else :)
92 abort ();
93 }
94
95 tw0 ()
96 : time_watcher (this, &tw0::cb)
97 { }
98} tw0;
99
100tstamp NOW;
101
102#if IOM_CHILD
103// sig_watcher for child signal(s)
104static struct sw0 : sig_watcher
105{
51 void cb (time_watcher &w) 106 void cb (sig_watcher &w)
107 {
108 // SIGCHLD, call corresponding watchera
109 pid_t pid;
110 int status;
111
112 while ((pid = waitpid (-1, &status, WNOHANG)) > 0)
113 for (int i = pw.size (); i--; )
114 {
115 child_watcher *w = pw[i];
116
117 if (!w)
118 pw.erase_unordered (i);
119 else if (w->pid == pid)
120 {
121 io_manager::unreg (*w);
122 w->call (*w, status);
123 }
124 }
125 }
126
127 sw0 ()
128 : sig_watcher (this, &sw0::cb)
129 { }
130} sw0;
131#endif
132
133#if IOM_TIME
134tstamp io_manager::now ()
135{
136 struct timeval tv;
137
138 gettimeofday (&tv, 0);
139 return (tstamp)tv.tv_sec + (tstamp)tv.tv_usec / 1000000.;
140}
141
142void io_manager::set_now ()
143{
144 NOW = now ();
145}
146#endif
147
148static bool iom_valid;
149
150// used for initialisation only
151static struct init {
152 init ()
153 {
154 iom_valid = true;
155
156#if IOM_SIG
157 sigemptyset (&sigs);
158
159 if (pipe (sigpipe))
160 {
161 perror ("io_manager: unable to create signal pipe, aborting.");
162 abort ();
163 }
164
165 fcntl (sigpipe[0], F_SETFL, O_NONBLOCK); fcntl (sigpipe[0], F_SETFD, FD_CLOEXEC);
166 fcntl (sigpipe[1], F_SETFL, O_NONBLOCK); fcntl (sigpipe[1], F_SETFD, FD_CLOEXEC);
167#endif
168
169#if IOM_CHILD
170 sw0.start (SIGCHLD);
171#endif
172
173#if IOM_TIME
174 io_manager::set_now ();
175
176 tw0.start (TSTAMP_MAX);
177#endif
178 }
179
180 ~init ()
181 {
182 iom_valid = false;
183 }
184
185 static void required ();
186} init;
187
188void
189init::required ()
190{
191 if (!iom_valid)
52 { 192 {
53 // should never get called 193 write (2, "io_manager: early registration attempt, aborting.\n",
54 // reached end-of-time, or tstamp has a bogus definition, 194 sizeof ("io_manager: early registration attempt, aborting.\n") - 1);
55 // or compiler initilization order broken, or somethine else :)
56 abort (); 195 abort ();
57 } 196 }
58 197}
59 tw0 ()
60 : time_watcher (this, &tw0::cb)
61 { }
62 } tw0;
63
64tstamp NOW;
65static bool iom_valid;
66io_manager iom;
67 198
68template<class watcher> 199template<class watcher>
69void io_manager::reg (watcher *w, io_manager_vec<watcher> &queue) 200void io_manager::reg (watcher &w, io_manager_vec<watcher> &queue)
70{ 201{
71 if (!iom_valid) 202 init::required ();
72 abort ();
73 203
74 if (!w->active) 204 if (!w.active)
75 { 205 {
76#if IOM_CHECK
77 queue.activity = true;
78#endif
79 queue.push_back (w); 206 queue.push_back (&w);
80 w->active = queue.size (); 207 w.active = queue.size ();
81 } 208 }
82} 209}
83 210
84template<class watcher> 211template<class watcher>
85void io_manager::unreg (watcher *w, io_manager_vec<watcher> &queue) 212void io_manager::unreg (watcher &w, io_manager_vec<watcher> &queue)
86{ 213{
87 if (!iom_valid) 214 if (!iom_valid)
88 return; 215 return;
89 216
90 if (w->active) 217 if (w.active)
91 { 218 {
92 queue [w->active - 1] = 0; 219 queue [w.active - 1] = 0;
93 w->active = 0; 220 w.active = 0;
94 } 221 }
95} 222}
96 223
97#if IOM_TIME 224#if IOM_TIME
98void time_watcher::trigger () 225void time_watcher::trigger ()
99{ 226{
100 call (*this); 227 call (*this);
101 228 io_manager::reg (*this);
102 iom.reg (this);
103} 229}
104 230
105void io_manager::reg (time_watcher *w) { reg (w, tw); } 231void io_manager::reg (time_watcher &w) { io_manager::reg (w, tw); }
106void io_manager::unreg (time_watcher *w) { unreg (w, tw); } 232void io_manager::unreg (time_watcher &w) { io_manager::unreg (w, tw); }
107#endif 233#endif
108 234
109#if IOM_IO 235#if IOM_IO
110void io_manager::reg (io_watcher *w) { reg (w, iow); } 236void io_manager::reg (io_watcher &w) { io_manager::reg (w, iow); }
111void io_manager::unreg (io_watcher *w) { unreg (w, iow); } 237void io_manager::unreg (io_watcher &w) { io_manager::unreg (w, iow); }
112#endif 238#endif
113 239
114#if IOM_CHECK 240#if IOM_CHECK
115void io_manager::reg (check_watcher *w) { reg (w, cw); } 241void io_manager::reg (check_watcher &w) { io_manager::reg (w, cw); }
116void io_manager::unreg (check_watcher *w) { unreg (w, cw); } 242void io_manager::unreg (check_watcher &w) { io_manager::unreg (w, cw); }
117#endif 243#endif
118 244
119#if IOM_IDLE 245#if IOM_IDLE
120void io_manager::reg (idle_watcher *w) { reg (w, iw); } 246void io_manager::reg (idle_watcher &w) { io_manager::reg (w, iw); }
121void io_manager::unreg (idle_watcher *w) { unreg (w, iw); } 247void 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 248#endif
134 249
135#if IOM_SIG 250#if IOM_SIG
136// race conditions galore 251static void
137 252sighandler (int signum)
138void io_manager::sighandler (int signum)
139{ 253{
140 assert (0 < signum && signum <= iom.sw.size ()); 254 sw [signum - 1]->pending = true;
141 255
142 sig_vec &sv = *iom.sw [signum - 1]; 256 // we use a pipe for signal notifications, as most current
143 257 // OSes (Linux...) do not implement pselect correctly. ugh.
144 for (int i = sv.size (); i--; ) 258 char ch = signum; // actual content not used
145 if (!sv[i]) 259 write (sigpipe[1], &ch, 1);
146 sv.erase_unordered (i);
147 else
148 sv[i]->call (*sv[i]);
149} 260}
150 261
151void io_manager::reg (sig_watcher *w) 262void io_manager::reg (sig_watcher &w)
152{ 263{
264 init::required ();
265
153 assert (0 < w->signum); 266 assert (0 < w.signum);
154 267
155 sw.reserve (w->signum); 268 sw.reserve (w.signum);
156 269
270 while (sw.size () < w.signum) // pathetic
271 sw.push_back (0);
272
157 sig_vec *&sv = sw [w->signum - 1]; 273 sig_vec *&sv = sw[w.signum - 1];
158 274
159 if (!sv) 275 if (!sv)
160 { 276 {
161 sv = new sig_vec; 277 sv = new sig_vec;
162 278
279 sigaddset (&sigs, w.signum);
280 sigprocmask (SIG_BLOCK, &sigs, NULL);
281
163 struct sigaction sa; 282 struct sigaction sa;
164 sa.sa_handler = io_manager::sighandler; 283 sa.sa_handler = sighandler;
165 sigfillset (&sa.sa_mask); 284 sigfillset (&sa.sa_mask);
166 sa.sa_flags = 0; 285 sa.sa_flags = SA_RESTART;
167 286
168 if (sigaction (w->signum, &sa, 0)) 287 if (sigaction (w.signum, &sa, 0))
169 { 288 {
170 perror ("Error while installing signal handler"); 289 perror ("io_manager: error while installing signal handler, ignoring.");
171 abort (); 290 abort ();
172 } 291 }
292
173 } 293 }
174 294
175 reg (w, *sv); 295 io_manager::reg (w, *sv);
176} 296}
177 297
178void io_manager::unreg (sig_watcher *w) 298void io_manager::unreg (sig_watcher &w)
179{ 299{
300 if (!w.active || !iom_valid)
301 return;
302
180 assert (0 < w->signum && w->signum <= sw.size ()); 303 assert (0 < w.signum && w.signum <= sw.size ());
181 304
182 unreg (w, *sw [w->signum - 1]); 305 io_manager::unreg (w, *sw[w.signum - 1]);
183} 306}
184 307
185void sig_watcher::start (int signum) 308void sig_watcher::start (int signum)
186{ 309{
187 stop (); 310 stop ();
188 this->signum = signum; 311 this->signum = signum;
189 iom.reg (this); 312 io_manager::reg (*this);
190} 313}
191#endif 314#endif
192 315
316#if IOM_CHILD
317void io_manager::reg (child_watcher &w) { io_manager::reg (w, pw); }
318void io_manager::unreg (child_watcher &w) { io_manager::unreg (w, pw); }
319#endif
320
193void io_manager::loop () 321void io_manager::loop ()
194{ 322{
323 init::required ();
324
195#if IOM_TIME 325#if IOM_TIME
196 set_now (); 326 set_now ();
197#endif 327#endif
198 328
199 for (;;) 329 for (;;)
200 { 330 {
201 struct timeval *to = 0;
202 struct timeval tval;
203 331
204#if IOM_IDLE 332#if IOM_TIME
205 if (iw.size ()) 333 // call pending time watchers
206 { 334 {
207 tval.tv_sec = 0; 335 bool activity;
208 tval.tv_usec = 0; 336
209 to = &tval;
210 } 337 do
211 else
212#endif
213
214 {
215#if IOM_TIME
216 time_watcher *next;
217
218 for (;;)
219 { 338 {
220 next = tw[0]; // the first time-watcher must exist at ALL times 339 activity = false;
221 340
222 for (int i = tw.size (); i--; ) 341 for (int i = tw.size (); i--; )
223 if (!tw[i]) 342 if (!tw[i])
224 tw.erase_unordered (i); 343 tw.erase_unordered (i);
225 else if (tw[i]->at < next->at) 344 else if (tw[i]->at <= NOW)
226 next = tw[i];
227
228 if (next->at > NOW)
229 { 345 {
230 if (next != tw[0]) 346 time_watcher &w = *tw[i];
231 { 347
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; 348 unreg (w);
349 w.call (w);
350
351 activity = true;
238 } 352 }
239 else
240 {
241 unreg (next);
242 next->call (*next);
243 }
244 } 353 }
245#endif 354 while (activity);
246
247 } 355 }
356#endif
248 357
249#if IOM_CHECK 358#if IOM_CHECK
250 tw.activity = false; 359 // call all check watchers
251
252 for (int i = cw.size (); i--; ) 360 for (int i = cw.size (); i--; )
253 if (!cw[i]) 361 if (!cw[i])
254 cw.erase_unordered (i); 362 cw.erase_unordered (i);
255 else 363 else
256 cw[i]->call (*cw[i]); 364 cw[i]->call (*cw[i]);
365#endif
257 366
258 if (tw.activity) 367 struct TIMEVAL *to = 0;
368 struct TIMEVAL tval;
369
370#if IOM_IDLE
371 if (iw.size ())
259 { 372 {
260 tval.tv_sec = 0; 373 tval.tv_sec = 0;
261 tval.tv_usec = 0; 374 tval.TV_FRAC = 0;
262 to = &tval; 375 to = &tval;
263 } 376 }
377 else
264#endif 378#endif
265 379 {
266#if IOM_IO 380#if IOM_TIME
381 // find earliest active watcher
382 time_watcher *next = tw[0]; // the first time-watcher must exist at ALL times
383
384 for (io_manager_vec<time_watcher>::const_iterator i = tw.end (); i-- > tw.begin (); )
385 if (*i && (*i)->at < next->at)
386 next = *i;
387
388 if (next->at > NOW && next != tw[0])
389 {
390 double diff = next->at - NOW;
391 tval.tv_sec = (int)diff;
392 tval.TV_FRAC = (int) ((diff - tval.tv_sec) * TV_MULT);
393 to = &tval;
394 }
395 }
396#endif
397
398#if IOM_IO || IOM_SIG
267 fd_set rfd, wfd; 399 fd_set rfd, wfd;
268 400
269 FD_ZERO (&rfd); 401 FD_ZERO (&rfd);
270 FD_ZERO (&wfd); 402 FD_ZERO (&wfd);
271 403
272 int fds = 0; 404 int fds = 0;
273 405
406# if IOM_IO
274 for (io_manager_vec<io_watcher>::iterator i = iow.end (); i-- > iow.begin (); ) 407 for (io_manager_vec<io_watcher>::const_iterator i = iow.end (); i-- > iow.begin (); )
275 if (*i) 408 if (*i)
276 { 409 {
277 if ((*i)->events & EVENT_READ ) FD_SET ((*i)->fd, &rfd); 410 if ((*i)->events & EVENT_READ ) FD_SET ((*i)->fd, &rfd);
278 if ((*i)->events & EVENT_WRITE) FD_SET ((*i)->fd, &wfd); 411 if ((*i)->events & EVENT_WRITE) FD_SET ((*i)->fd, &wfd);
279 412
280 if ((*i)->fd >= fds) fds = (*i)->fd + 1; 413 if ((*i)->fd >= fds) fds = (*i)->fd + 1;
281 } 414 }
415# endif
282 416
283 if (!to && !fds) //TODO: also check idle_watchers and check_watchers 417 if (!to && !fds) //TODO: also check idle_watchers and check_watchers?
284 break; // no events 418 break; // no events
285 419
420# if IOM_SIG
421 FD_SET (sigpipe[0], &rfd);
422 if (sigpipe[0] >= fds) fds = sigpipe[0] + 1;
423# endif
424
425# if IOM_SIG
426 // there is no race, as we use a pipe for signals, so select
427 // will return if a signal is caught.
428 sigprocmask (SIG_UNBLOCK, &sigs, NULL);
429# endif
286 fds = select (fds, &rfd, &wfd, NULL, to); 430 fds = select (fds, &rfd, &wfd, NULL, to);
431# if IOM_SIG
432 sigprocmask (SIG_BLOCK, &sigs, NULL);
433# endif
434
287# if IOM_TIME 435# if IOM_TIME
436 {
437 // update time, try to compensate for gross non-monotonic time changes
438 tstamp diff = NOW;
288 set_now (); 439 set_now ();
440 diff = NOW - diff;
441
442 if (diff < 0)
443 for (io_manager_vec<time_watcher>::const_iterator i = tw.end (); i-- > tw.begin (); )
444 if (*i)
445 (*i)->at += diff;
446 }
289# endif 447# endif
290 448
291 if (fds > 0) 449 if (fds > 0)
292 for (int i = iow.size (); i--; ) 450 {
293 if (!iow[i]) 451# if IOM_SIG
294 iow.erase_unordered (i); 452 if (FD_ISSET (sigpipe[0], &rfd))
295 else
296 { 453 {
297 short revents = iow[i]->events; 454 char ch;
298 455
299 if (!FD_ISSET (iow[i]->fd, &rfd)) revents &= ~EVENT_READ; 456 while (read (sigpipe[0], &ch, 1) > 0)
300 if (!FD_ISSET (iow[i]->fd, &wfd)) revents &= ~EVENT_WRITE; 457 ;
301 458
302 if (revents) 459 for (vector<sig_vec *>::iterator svp = sw.end (); svp-- > sw.begin (); )
303 iow[i]->call (*iow[i], revents); 460 if (*svp && (*svp)->pending)
461 {
462 sig_vec &sv = **svp;
463 for (int i = sv.size (); i--; )
464 if (!sv[i])
465 sv.erase_unordered (i);
466 else
467 sv[i]->call (*sv[i]);
468
469 sv.pending = false;
470 }
304 } 471 }
472# endif
473
474# if IOM_IO
475 for (int i = iow.size (); i--; )
476 if (!iow[i])
477 iow.erase_unordered (i);
478 else
479 {
480 io_watcher &w = *iow[i];
481 short revents = w.events;
482
483 if (!FD_ISSET (w.fd, &rfd)) revents &= ~EVENT_READ;
484 if (!FD_ISSET (w.fd, &wfd)) revents &= ~EVENT_WRITE;
485
486 if (revents)
487 w.call (w, revents);
488 }
489#endif
490 }
305 else if (fds < 0 && errno != EINTR) 491 else if (fds < 0 && errno != EINTR)
306 { 492 {
307 perror ("Error while waiting for I/O or time event"); 493 perror ("io_manager: fatal error while waiting for I/O or time event, aborting.");
308 abort (); 494 abort ();
309 } 495 }
310#if IOM_IDLE 496#if IOM_IDLE
311 else 497 else
312 for (int i = iw.size (); i--; ) 498 for (int i = iw.size (); i--; )
… …
323 select (0, 0, 0, 0, &to); 509 select (0, 0, 0, 0, &to);
324 set_now (); 510 set_now ();
325#else 511#else
326 break; 512 break;
327#endif 513#endif
328
329 } 514 }
330} 515}
331 516
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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