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Comparing gvpe/src/iom.C (file contents):
Revision 1.11 by pcg, Sat Apr 5 02:32:40 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 "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#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 (*this); 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
58time_watcher::~time_watcher () 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 (iom_valid) 187#endif
61 iom.unreg (this);
62}
63 188
64void io_watcher::set(int fd_, short events_) 189#if IOM_IO
65{ 190void io_manager::reg (io_watcher &w) { io_manager::reg (w, iow); }
66 fd = fd_; 191void io_manager::unreg (io_watcher &w) { io_manager::unreg (w, iow); }
67 events = events_; 192#endif
68 193
69 if (registered) 194#if IOM_CHECK
70 { 195void io_manager::reg (check_watcher &w) { io_manager::reg (w, cw); }
71 iom.unreg (this); 196void io_manager::unreg (check_watcher &w) { io_manager::unreg (w, cw); }
72 iom.reg (this); 197#endif
73 }
74}
75 198
76io_watcher::~io_watcher () 199#if IOM_IDLE
77{ 200void io_manager::reg (idle_watcher &w) { io_manager::reg (w, iw); }
78 if (iom_valid) 201void io_manager::unreg (idle_watcher &w) { io_manager::unreg (w, iw); }
79 iom.unreg (this); 202#endif
80}
81 203
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
82void io_manager::reg (io_watcher *w) 216void io_manager::reg (sig_watcher &w)
83{ 217{
84 if (!w->registered) 218 assert (0 < w.signum);
85 {
86 w->registered = true;
87 219
88 pollfd pfd; 220 sw.reserve (w.signum);
89 221
90 pfd.fd = w->fd; 222 while (sw.size () < w.signum) // pathetic
91 pfd.events = w->events;
92
93 pfs.push_back (pfd);
94 iow.push_back (w); 223 sw.push_back (0);
224
225 sig_vec *&sv = sw[w.signum - 1];
226
227 if (!sv)
95 } 228 {
96} 229 sv = new sig_vec;
97 230
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
98void io_manager::unreg (io_watcher *w) 250void io_manager::unreg (sig_watcher &w)
99{ 251{
100 if (w->registered) 252 if (!w.active)
101 { 253 return;
102 w->registered = false;
103 254
104 unsigned int sz = iow.size (); 255 assert (0 < w.signum && w.signum <= sw.size ());
105 unsigned int i = find (iow.begin (), iow.end (), w) - iow.begin (); 256
257 io_manager::unreg (w, *sw[w.signum - 1]);
258}
106 259
107 assert (i != sz); 260void sig_watcher::start (int signum)
261{
262 stop ();
263 this->signum = signum;
264 io_manager::reg (*this);
265}
266#endif
108 267
109 if (sz == 1) 268void io_manager::loop ()
110 { 269{
111 pfs.clear (); 270 init::required ();
112 iow.clear (); 271
272#if IOM_TIME
273 set_now ();
274#endif
275
276 for (;;)
277 {
278 struct TIMEVAL *to = 0;
279 struct TIMEVAL tval;
280
281#if IOM_IDLE
282 if (iw.size ())
113 } 283 {
114 else if (i == sz - 1) 284 tval.tv_sec = 0;
115 { 285 tval.TV_FRAC = 0;
116 iow.pop_back (); 286 to = &tval;
117 pfs.pop_back ();
118 } 287 }
119 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)
120 { 352 {
121 iow[i] = iow[sz - 1]; iow.pop_back (); 353 if ((*i)->events & EVENT_READ ) FD_SET ((*i)->fd, &rfd);
122 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;
123 } 357 }
124 } 358# endif
125}
126 359
127void io_manager::reschedule_time_watchers () 360 if (!to && !fds) //TODO: also check idle_watchers and check_watchers
128{ 361 break; // no events
129 make_heap (tw.begin (), tw.end (), earliest_first);
130}
131 362
132void io_manager::reg (time_watcher *w) 363# if IOM_SIG
133{ 364 FD_SET (sigpipe[0], &rfd);
134 if (!w->registered) 365 if (sigpipe[0] >= fds) fds = sigpipe[0] + 1;
135 { 366# endif
136 w->registered = true;
137 367
138 tw.push_back (w); 368# if IOM_SIG
139 push_heap (tw.begin (), tw.end (), earliest_first); 369 // there is no race, as we use a pipe for signals, so select
140 } 370 // will return if a signal is caught.
141} 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
142 377
143void io_manager::unreg (time_watcher *w) 378# if IOM_TIME
144{
145 if (w->registered)
146 {
147 w->registered = false;
148
149 unsigned int sz = tw.size ();
150 unsigned int i = find (tw.begin (), tw.end (), w) - tw.begin ();
151
152 assert (i != sz);
153
154 if (i != sz - 1)
155 tw[i] = tw[sz - 1];
156
157 tw.pop_back ();
158 reschedule_time_watchers ();
159 }
160}
161
162inline void set_now (void)
163{
164 struct timeval tv;
165
166 gettimeofday (&tv, 0);
167
168 NOW = (tstamp)tv.tv_sec + (tstamp)tv.tv_usec / 1000000;
169}
170
171void io_manager::loop ()
172{
173 set_now ();
174
175 for (;;)
176 {
177 while (tw[0]->at <= NOW)
178 {
179 // remove the first watcher
180 time_watcher *w = tw[0];
181
182 pop_heap (tw.begin (), tw.end (), earliest_first);
183 tw.pop_back ();
184
185 w->registered = false;
186
187 // call it
188 w->call (*w);
189
190 // re-add it if necessary
191 if (w->at >= 0 && !w->registered)
192 reg (w);
193 }
194
195 int timeout = (int) ((tw[0]->at - NOW) * 1000);
196
197 int fds = poll (&pfs[0], pfs.size (), timeout);
198
199 set_now (); 379 set_now ();
380# endif
200 381
201 vector<io_watcher *>::iterator w; 382 if (fds > 0)
202 vector<pollfd>::iterator p; 383 {
203 384# if IOM_SIG
204 for (w = iow.begin (), p = pfs.begin (); 385 if (FD_ISSET (sigpipe[0], &rfd))
205 fds > 0 && w < iow.end ();
206 ++w, ++p)
207 if (p->revents)
208 { 386 {
387 char ch;
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 }
209 --fds; 404 }
405# endif
210 406
211 if (p->revents & POLLNVAL) 407# if IOM_IO
408 for (int i = iow.size (); i--; )
409 if (!iow[i])
410 iow.erase_unordered (i);
411 else
212 { 412 {
213 slog (L_ERR, _("io_watcher started on illegal file descriptor, disabling.")); 413 short revents = iow[i]->events;
214 (*w)->stop (); 414
415 if (!FD_ISSET (iow[i]->fd, &rfd)) revents &= ~EVENT_READ;
416 if (!FD_ISSET (iow[i]->fd, &wfd)) revents &= ~EVENT_WRITE;
417
418 if (revents)
419 iow[i]->call (*iow[i], revents);
215 } 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);
216 else 433 else
217 (*w)->call (**w, p->revents); 434 iw[i]->call (*iw[i]);
218 } 435#endif
219 }
220}
221 436
222void io_manager::idle_cb (time_watcher &w) 437#elif IOM_TIME
223{ 438 if (!to)
224 w.at = NOW + 86400; // wake up every day, for no good reason 439 break;
225}
226 440
227io_manager::io_manager () 441 select (0, 0, 0, 0, &to);
228{
229 iom_valid = true;
230
231 set_now (); 442 set_now ();
232 idle = new time_watcher (this, &io_manager::idle_cb); 443#else
233 idle->start (0); 444 break;
445#endif
446 }
234} 447}
235 448
236io_manager::~io_manager ()
237{
238 iom_valid = false;
239}
240

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