ViewVC Help
View File | Revision Log | Show Annotations | Download File
/cvs/gvpe/src/iom.C
(Generate patch)

Comparing gvpe/src/iom.C (file contents):
Revision 1.11 by pcg, Sat Apr 5 02:32:40 2003 UTC vs.
Revision 1.24 by pcg, Fri Nov 12 12:49:12 2004 UTC

1/* 1/*
2 iom.C -- I/O multiplexor 2 iom.C -- generic I/O multiplexer
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 "gettext.h" 30#if 1 // older unices need these includes for select (2)
27 31# include <unistd.h>
28#include "slog.h" 32# include <sys/types.h>
29#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;
30 95
31tstamp 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
32bool iom_valid; 108static bool iom_valid;
33io_manager iom;
34 109
35inline bool earliest_first (const time_watcher *a, const time_watcher *b) 110// used for initialisation only
36{ 111static struct init {
37 return a->at > b->at; 112 init ()
38} 113 {
114#if IOM_SIG
115 sigemptyset (&sigs);
39 116
40void time_watcher::set (tstamp when) 117 if (pipe (sigpipe))
41{ 118 {
42 at = when; 119 perror ("io_manager: unable to create signal pipe, aborting.");
120 abort ();
121 }
43 122
44 if (registered) 123 fcntl (sigpipe[0], F_SETFL, O_NONBLOCK);
45 iom.reschedule_time_watchers (); 124 fcntl (sigpipe[1], F_SETFL, O_NONBLOCK);
46} 125#endif
47 126
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
48void time_watcher::trigger () 176void time_watcher::trigger ()
49{ 177{
50 call (*this); 178 call (*this);
51 179 io_manager::reg (*this);
52 if (registered)
53 iom.reschedule_time_watchers ();
54 else
55 iom.reg (this);
56} 180}
57 181
58time_watcher::~time_watcher () 182void io_manager::reg (time_watcher &w) { io_manager::reg (w, tw); }
59{ 183void io_manager::unreg (time_watcher &w) { io_manager::unreg (w, tw); }
60 if (iom_valid) 184#endif
61 iom.unreg (this);
62}
63 185
64void io_watcher::set(int fd_, short events_) 186#if IOM_IO
65{ 187void io_manager::reg (io_watcher &w) { io_manager::reg (w, iow); }
66 fd = fd_; 188void io_manager::unreg (io_watcher &w) { io_manager::unreg (w, iow); }
67 events = events_; 189#endif
68 190
69 if (registered) 191#if IOM_CHECK
70 { 192void io_manager::reg (check_watcher &w) { io_manager::reg (w, cw); }
71 iom.unreg (this); 193void io_manager::unreg (check_watcher &w) { io_manager::unreg (w, cw); }
72 iom.reg (this); 194#endif
73 }
74}
75 195
76io_watcher::~io_watcher () 196#if IOM_IDLE
77{ 197void io_manager::reg (idle_watcher &w) { io_manager::reg (w, iw); }
78 if (iom_valid) 198void io_manager::unreg (idle_watcher &w) { io_manager::unreg (w, iw); }
79 iom.unreg (this); 199#endif
80}
81 200
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
82void io_manager::reg (io_watcher *w) 213void io_manager::reg (sig_watcher &w)
83{ 214{
84 if (!w->registered) 215 assert (0 < w.signum);
85 {
86 w->registered = true;
87 216
88 pollfd pfd; 217 sw.reserve (w.signum);
89 218
90 pfd.fd = w->fd; 219 while (sw.size () < w.signum) // pathetic
91 pfd.events = w->events;
92
93 pfs.push_back (pfd);
94 iow.push_back (w); 220 sw.push_back (0);
221
222 sig_vec *&sv = sw[w.signum - 1];
223
224 if (!sv)
95 } 225 {
96} 226 sv = new sig_vec;
97 227
98void io_manager::unreg (io_watcher *w) 228 sigaddset (&sigs, w.signum);
99{ 229 sigprocmask (SIG_BLOCK, &sigs, NULL);
100 if (w->registered)
101 {
102 w->registered = false;
103 230
104 unsigned int sz = iow.size (); 231 struct sigaction sa;
105 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;
106 235
107 assert (i != sz); 236 if (sigaction (w.signum, &sa, 0))
108
109 if (sz == 1)
110 { 237 {
238 perror ("io_manager: error while installing signal handler, ignoring.");
111 pfs.clear (); 239 abort ();
112 iow.clear ();
113 } 240 }
114 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)
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 ())
115 { 316 {
116 iow.pop_back (); 317 tval.tv_sec = 0;
117 pfs.pop_back (); 318 tval.TV_FRAC = 0;
319 to = &tval;
118 } 320 }
119 else 321 else
322#endif
120 { 323 {
121 iow[i] = iow[sz - 1]; iow.pop_back (); 324#if IOM_TIME
122 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 }
123 } 339 }
124 } 340#endif
125}
126 341
127void io_manager::reschedule_time_watchers () 342#if IOM_IO || IOM_SIG
128{ 343 fd_set rfd, wfd;
129 make_heap (tw.begin (), tw.end (), earliest_first);
130}
131 344
132void io_manager::reg (time_watcher *w) 345 FD_ZERO (&rfd);
133{ 346 FD_ZERO (&wfd);
134 if (!w->registered)
135 {
136 w->registered = true;
137 347
138 tw.push_back (w); 348 int fds = 0;
139 push_heap (tw.begin (), tw.end (), earliest_first);
140 }
141}
142 349
143void io_manager::unreg (time_watcher *w) 350# if IOM_IO
144{ 351 for (io_manager_vec<io_watcher>::const_iterator i = iow.end (); i-- > iow.begin (); )
145 if (w->registered) 352 if (*i)
146 { 353 {
147 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);
148 356
149 unsigned int sz = tw.size (); 357 if ((*i)->fd >= fds) fds = (*i)->fd + 1;
150 unsigned int i = find (tw.begin (), tw.end (), w) - tw.begin (); 358 }
359# endif
151 360
152 assert (i != sz); 361 if (!to && !fds) //TODO: also check idle_watchers and check_watchers?
153 362 break; // no events
154 if (i != sz - 1)
155 tw[i] = tw[sz - 1];
156 363
157 tw.pop_back (); 364# if IOM_SIG
158 reschedule_time_watchers (); 365 FD_SET (sigpipe[0], &rfd);
159 } 366 if (sigpipe[0] >= fds) fds = sigpipe[0] + 1;
160} 367# endif
161 368
162inline void set_now (void) 369# if IOM_SIG
163{ 370 // there is no race, as we use a pipe for signals, so select
164 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
165 378
166 gettimeofday (&tv, 0); 379# if IOM_TIME
167
168 NOW = (tstamp)tv.tv_sec + (tstamp)tv.tv_usec / 1000000;
169}
170
171void io_manager::loop ()
172{
173 set_now (); 380 set_now ();
381# endif
174 382
175 for (;;) 383 if (fds > 0)
176 {
177 while (tw[0]->at <= NOW)
178 { 384 {
179 // remove the first watcher 385# if IOM_SIG
180 time_watcher *w = tw[0]; 386 if (FD_ISSET (sigpipe[0], &rfd))
387 {
388 char ch;
181 389
182 pop_heap (tw.begin (), tw.end (), earliest_first); 390 while (read (sigpipe[0], &ch, 1) > 0)
183 tw.pop_back (); 391 ;
184 392
185 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]);
186 402
187 // call it 403 sv.pending = false;
188 w->call (*w); 404 }
405 }
406# endif
189 407
190 // re-add it if necessary 408# if IOM_IO
191 if (w->at >= 0 && !w->registered) 409 for (int i = iow.size (); i--; )
192 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
193 } 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
194 437
195 int timeout = (int) ((tw[0]->at - NOW) * 1000); 438#elif IOM_TIME
439 if (!to)
440 break;
196 441
197 int fds = poll (&pfs[0], pfs.size (), timeout); 442 select (0, 0, 0, 0, &to);
198
199 set_now (); 443 set_now ();
200 444#else
201 vector<io_watcher *>::iterator w; 445 break;
202 vector<pollfd>::iterator p; 446#endif
203
204 for (w = iow.begin (), p = pfs.begin ();
205 fds > 0 && w < iow.end ();
206 ++w, ++p)
207 if (p->revents)
208 {
209 --fds;
210
211 if (p->revents & POLLNVAL)
212 {
213 slog (L_ERR, _("io_watcher started on illegal file descriptor, disabling."));
214 (*w)->stop ();
215 }
216 else
217 (*w)->call (**w, p->revents);
218 }
219 } 447 }
220} 448}
221 449
222void io_manager::idle_cb (time_watcher &w)
223{
224 w.at = NOW + 86400; // wake up every day, for no good reason
225}
226
227io_manager::io_manager ()
228{
229 iom_valid = true;
230
231 set_now ();
232 idle = new time_watcher (this, &io_manager::idle_cb);
233 idle->start (0);
234}
235
236io_manager::~io_manager ()
237{
238 iom_valid = false;
239}
240

Diff Legend

– Removed lines
+ Added lines
< Changed lines
> Changed lines