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Comparing gvpe/src/iom.C (file contents):
Revision 1.8 by pcg, Wed Apr 2 05:15:00 2003 UTC vs.
Revision 1.21 by pcg, Thu Sep 2 07:50:43 2004 UTC

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

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