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Comparing gvpe/src/iom.C (file contents):
Revision 1.12 by pcg, Thu Oct 16 02:41:21 2003 UTC vs.
Revision 1.22 by pcg, Thu Nov 11 17:41:55 2004 UTC

1/* 1/*
2 iom.C -- generic I/O multiplexor 2 iom.C -- generic I/O multiplexor
3 Copyright (C) 2003 Marc Lehmann <pcg@goof.com> 3 Copyright (C) 2003, 2004 Marc Lehmann <pcg@goof.com>
4 4
5 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
6 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
7 the Free Software Foundation; either version 2 of the License, or 7 the Free Software Foundation; either version 2 of the License, or
8 (at your option) any later version. 8 (at your option) any later version.
… …
15 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
16 along with this program; if not, write to the Free Software 16 along with this program; if not, write to the Free Software
17 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
18*/ 18*/
19 19
20#include "config.h" 20#include "iom.h"
21
22#include <cstdio>
23#include <cstdlib>
24#include <cerrno>
21 25
22#include <sys/time.h> 26#include <sys/time.h>
23 27
24#include <algorithm> 28#include <assert.h>
25#include <functional>
26 29
27#include "gettext.h" 30#if 1 // older unices need these includes for select (2)
28 31# include <unistd.h>
29#include "slog.h" 32# include <sys/types.h>
30#include "iom.h" 33# include <time.h>
34#endif
35
36// for IOM_SIG
37#if IOM_SIG
38# include <signal.h>
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;
31 95
32tstamp NOW; 96tstamp NOW;
97
98#if IOM_TIME
99inline void set_now (void)
100{
101 struct timeval tv;
102
103 gettimeofday (&tv, 0);
104 NOW = (tstamp)tv.tv_sec + (tstamp)tv.tv_usec / 1000000.;
105}
106#endif
107
33bool iom_valid; 108static bool iom_valid;
34io_manager iom;
35 109
36inline bool earliest_first (const time_watcher *a, const time_watcher *b) 110// used for initialisation only
37{ 111static struct init {
38 return a->at > b->at; 112 init ()
39} 113 {
114#if IOM_SIG
115 sigemptyset (&sigs);
40 116
41void time_watcher::set (tstamp when) 117 if (pipe (sigpipe))
42{ 118 {
43 at = when; 119 perror ("io_manager: unable to create signal pipe, aborting.");
120 abort ();
121 }
44 122
45 if (registered) 123 fcntl (sigpipe[0], F_SETFL, O_NONBLOCK);
46 iom.reschedule_time_watchers (); 124 fcntl (sigpipe[1], F_SETFL, O_NONBLOCK);
47} 125#endif
48 126
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
49void time_watcher::trigger () 176void time_watcher::trigger ()
50{ 177{
51 call (*this); 178 call (*this);
52 179 io_manager::reg (*this);
53 if (registered)
54 iom.reschedule_time_watchers ();
55 else
56 iom.reg (this);
57} 180}
58 181
59time_watcher::~time_watcher () 182void io_manager::reg (time_watcher &w) { io_manager::reg (w, tw); }
60{ 183void io_manager::unreg (time_watcher &w) { io_manager::unreg (w, tw); }
61 if (iom_valid) 184#endif
62 iom.unreg (this);
63}
64 185
65void io_watcher::set(int fd_, short events_) 186#if IOM_IO
66{ 187void io_manager::reg (io_watcher &w) { io_manager::reg (w, iow); }
67 fd = fd_; 188void io_manager::unreg (io_watcher &w) { io_manager::unreg (w, iow); }
68 events = events_; 189#endif
69 190
70 if (registered) 191#if IOM_CHECK
71 { 192void io_manager::reg (check_watcher &w) { io_manager::reg (w, cw); }
72 iom.unreg (this); 193void io_manager::unreg (check_watcher &w) { io_manager::unreg (w, cw); }
73 iom.reg (this); 194#endif
74 }
75}
76 195
77io_watcher::~io_watcher () 196#if IOM_IDLE
78{ 197void io_manager::reg (idle_watcher &w) { io_manager::reg (w, iw); }
79 if (iom_valid) 198void io_manager::unreg (idle_watcher &w) { io_manager::unreg (w, iw); }
80 iom.unreg (this); 199#endif
81}
82 200
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
83void io_manager::reg (io_watcher *w) 213void io_manager::reg (sig_watcher &w)
84{ 214{
85 if (!w->registered) 215 assert (0 < w.signum);
86 {
87 w->registered = true;
88 216
89 pollfd pfd; 217 sw.reserve (w.signum);
90 218
91 pfd.fd = w->fd; 219 while (sw.size () < w.signum) // pathetic
92 pfd.events = w->events;
93
94 pfs.push_back (pfd);
95 iow.push_back (w); 220 sw.push_back (0);
221
222 sig_vec *&sv = sw[w.signum - 1];
223
224 if (!sv)
96 } 225 {
97} 226 sv = new sig_vec;
98 227
99void io_manager::unreg (io_watcher *w) 228 sigaddset (&sigs, w.signum);
100{ 229 sigprocmask (SIG_BLOCK, &sigs, NULL);
101 if (w->registered)
102 {
103 w->registered = false;
104 230
105 unsigned int sz = iow.size (); 231 struct sigaction sa;
106 unsigned int i = find (iow.begin (), iow.end (), w) - iow.begin (); 232 sa.sa_handler = sighandler;
233 sigfillset (&sa.sa_mask);
234 sa.sa_flags = SA_RESTART;
107 235
108 assert (i != sz); 236 if (sigaction (w.signum, &sa, 0))
109
110 if (sz == 1)
111 { 237 {
238 perror ("io_manager: error while installing signal handler, ignoring.");
112 pfs.clear (); 239 abort ();
113 iow.clear ();
114 } 240 }
115 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 ())
116 { 316 {
117 iow.pop_back (); 317 tval.tv_sec = 0;
118 pfs.pop_back (); 318 tval.TV_FRAC = 0;
319 to = &tval;
119 } 320 }
120 else 321 else
322#endif
121 { 323 {
122 iow[i] = iow[sz - 1]; iow.pop_back (); 324#if IOM_TIME
123 pfs[i] = pfs[sz - 1]; pfs.pop_back (); 325 // find earliest active watcher
326 time_watcher *next = tw[0]; // the first time-watcher must exist at ALL times
327
328 for (io_manager_vec<time_watcher>::const_iterator i = tw.end (); i-- > tw.begin (); )
329 if (*i && (*i)->at < next->at)
330 next = *i;
331
332 if (next->at > NOW && next != tw[0])
333 {
334 double diff = next->at - NOW;
335 tval.tv_sec = (int)diff;
336 tval.TV_FRAC = (int) ((diff - tval.tv_sec) * TV_MULT);
337 to = &tval;
338 }
124 } 339 }
125 } 340#endif
126}
127 341
128void io_manager::reschedule_time_watchers () 342#if IOM_IO || IOM_SIG
129{ 343 fd_set rfd, wfd;
130 make_heap (tw.begin (), tw.end (), earliest_first);
131}
132 344
133void io_manager::reg (time_watcher *w) 345 FD_ZERO (&rfd);
134{ 346 FD_ZERO (&wfd);
135 if (!w->registered)
136 {
137 w->registered = true;
138 347
139 tw.push_back (w); 348 int fds = 0;
140 push_heap (tw.begin (), tw.end (), earliest_first);
141 }
142}
143 349
144void io_manager::unreg (time_watcher *w) 350# if IOM_IO
145{ 351 for (io_manager_vec<io_watcher>::const_iterator i = iow.end (); i-- > iow.begin (); )
146 if (w->registered) 352 if (*i)
147 { 353 {
148 w->registered = false; 354 if ((*i)->events & EVENT_READ ) FD_SET ((*i)->fd, &rfd);
355 if ((*i)->events & EVENT_WRITE) FD_SET ((*i)->fd, &wfd);
149 356
150 unsigned int sz = tw.size (); 357 if ((*i)->fd >= fds) fds = (*i)->fd + 1;
151 unsigned int i = find (tw.begin (), tw.end (), w) - tw.begin (); 358 }
359# endif
152 360
153 assert (i != sz); 361 if (!to && !fds) //TODO: also check idle_watchers and check_watchers?
154 362 break; // no events
155 if (i != sz - 1)
156 tw[i] = tw[sz - 1];
157 363
158 tw.pop_back (); 364# if IOM_SIG
159 reschedule_time_watchers (); 365 FD_SET (sigpipe[0], &rfd);
160 } 366 if (sigpipe[0] >= fds) fds = sigpipe[0] + 1;
161} 367# endif
162 368
163inline void set_now (void) 369# if IOM_SIG
164{ 370 // there is no race, as we use a pipe for signals, so select
165 struct timeval tv; 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
166 378
167 gettimeofday (&tv, 0); 379# if IOM_TIME
168
169 NOW = (tstamp)tv.tv_sec + (tstamp)tv.tv_usec / 1000000;
170}
171
172void io_manager::loop ()
173{
174 set_now (); 380 set_now ();
381# endif
175 382
176 for (;;) 383 if (fds > 0)
177 {
178 while (tw[0]->at <= NOW)
179 { 384 {
180 // remove the first watcher 385# if IOM_SIG
181 time_watcher *w = tw[0]; 386 if (FD_ISSET (sigpipe[0], &rfd))
387 {
388 char ch;
182 389
183 pop_heap (tw.begin (), tw.end (), earliest_first); 390 while (read (sigpipe[0], &ch, 1) > 0)
184 tw.pop_back (); 391 ;
185 392
186 w->registered = false; 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]);
187 402
188 // call it 403 sv.pending = false;
189 w->call (*w); 404 }
405 }
406# endif
190 407
191 // re-add it if necessary 408# if IOM_IO
192 if (w->at >= 0 && !w->registered) 409 for (int i = iow.size (); i--; )
193 reg (w); 410 if (!iow[i])
411 iow.erase_unordered (i);
412 else
413 {
414 short revents = iow[i]->events;
415
416 if (!FD_ISSET (iow[i]->fd, &rfd)) revents &= ~EVENT_READ;
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
194 } 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
195 437
196 int timeout = (int) ((tw[0]->at - NOW) * 1000); 438#elif IOM_TIME
439 if (!to)
440 break;
197 441
198 int fds = poll (&pfs[0], pfs.size (), timeout); 442 select (0, 0, 0, 0, &to);
199
200 set_now (); 443 set_now ();
201 444#else
202 vector<io_watcher *>::iterator w; 445 break;
203 vector<pollfd>::iterator p; 446#endif
204
205 for (w = iow.begin (), p = pfs.begin ();
206 fds > 0 && w < iow.end ();
207 ++w, ++p)
208 if (p->revents)
209 {
210 --fds;
211
212 if (p->revents & POLLNVAL)
213 {
214 slog (L_ERR, _("io_watcher started on illegal file descriptor, disabling."));
215 (*w)->stop ();
216 }
217 else
218 (*w)->call (**w, p->revents);
219 }
220 } 447 }
221} 448}
222 449
223void io_manager::idle_cb (time_watcher &w)
224{
225 w.at = NOW + 86400; // wake up every day, for no good reason
226}
227
228io_manager::io_manager ()
229{
230 iom_valid = true;
231
232 set_now ();
233 idle = new time_watcher (this, &io_manager::idle_cb);
234 idle->start (0);
235}
236
237io_manager::~io_manager ()
238{
239 iom_valid = false;
240}
241

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