1 |
/* |
2 |
iom.C -- generic I/O multiplexer |
3 |
Copyright (C) 2003-2006 Marc Lehmann <gvpe@schmorp.de> |
4 |
|
5 |
This file is part of GVPE. |
6 |
|
7 |
GVPE is free software; you can redistribute it and/or modify |
8 |
it under the terms of the GNU General Public License as published by |
9 |
the Free Software Foundation; either version 2 of the License, or |
10 |
(at your option) any later version. |
11 |
|
12 |
This program is distributed in the hope that it will be useful, |
13 |
but WITHOUT ANY WARRANTY; without even the implied warranty of |
14 |
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
15 |
GNU General Public License for more details. |
16 |
|
17 |
You should have received a copy of the GNU General Public License |
18 |
along with gvpe; if not, write to the Free Software |
19 |
Foundation, Inc. 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
20 |
*/ |
21 |
|
22 |
#include "iom.h" |
23 |
|
24 |
#include <cstdio> |
25 |
#include <cstdlib> |
26 |
#include <cerrno> |
27 |
#include <cassert> |
28 |
|
29 |
#include <sys/types.h> |
30 |
#include <sys/time.h> |
31 |
|
32 |
#if 1 // older unices need these includes for select (2) |
33 |
# include <unistd.h> |
34 |
# include <time.h> |
35 |
#endif |
36 |
|
37 |
#if IOM_CHILD |
38 |
# include <sys/wait.h> |
39 |
#endif |
40 |
|
41 |
#if IOM_SIG |
42 |
# include <csignal> |
43 |
# include <fcntl.h> |
44 |
#endif |
45 |
|
46 |
// if the BSDs would at least be marginally POSIX-compatible.. *sigh* |
47 |
// until that happens, sys/select.h must come last |
48 |
#include <sys/select.h> |
49 |
|
50 |
#define TIMEVAL timeval |
51 |
#define TV_FRAC tv_usec |
52 |
#define TV_MULT 1000000L |
53 |
|
54 |
#if IOM_IO |
55 |
static io_manager_vec<io_watcher> iow; |
56 |
#endif |
57 |
#if IOM_CHECK |
58 |
static io_manager_vec<check_watcher> cw; |
59 |
#endif |
60 |
#if IOM_TIME |
61 |
static io_manager_vec<time_watcher> tw; |
62 |
#endif |
63 |
#if IOM_IDLE |
64 |
static io_manager_vec<idle_watcher> iw; |
65 |
#endif |
66 |
#if IOM_SIG |
67 |
static int sigpipe[2]; // signal signalling pipe |
68 |
static sigset_t sigs; |
69 |
struct sig_vec : io_manager_vec<sig_watcher> { |
70 |
int pending; |
71 |
sig_vec () |
72 |
: pending (false) |
73 |
{ } |
74 |
}; |
75 |
static vector<sig_vec *> sw; |
76 |
#endif |
77 |
#if IOM_CHILD |
78 |
static io_manager_vec<child_watcher> pw; |
79 |
#endif |
80 |
|
81 |
// this is a dummy time watcher to ensure that the first |
82 |
// time watcher is _always_ valid, this gets rid of a lot |
83 |
// of null-pointer-checks |
84 |
// (must come _before_ iom is being defined) |
85 |
static struct tw0 : time_watcher |
86 |
{ |
87 |
void cb (time_watcher &w) |
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 |
|
100 |
tstamp NOW; |
101 |
|
102 |
#if IOM_CHILD |
103 |
// sig_watcher for child signal(s) |
104 |
static struct sw0 : sig_watcher |
105 |
{ |
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 |
134 |
tstamp 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 |
|
142 |
void io_manager::set_now () |
143 |
{ |
144 |
NOW = now (); |
145 |
} |
146 |
#endif |
147 |
|
148 |
static bool iom_valid; |
149 |
|
150 |
// used for initialisation only |
151 |
static 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 |
|
188 |
void |
189 |
init::required () |
190 |
{ |
191 |
if (!iom_valid) |
192 |
{ |
193 |
write (2, "io_manager: early registration attempt, aborting.\n", |
194 |
sizeof ("io_manager: early registration attempt, aborting.\n") - 1); |
195 |
abort (); |
196 |
} |
197 |
} |
198 |
|
199 |
template<class watcher> |
200 |
void io_manager::reg (watcher &w, io_manager_vec<watcher> &queue) |
201 |
{ |
202 |
init::required (); |
203 |
|
204 |
if (!w.active) |
205 |
{ |
206 |
queue.push_back (&w); |
207 |
w.active = queue.size (); |
208 |
} |
209 |
} |
210 |
|
211 |
template<class watcher> |
212 |
void io_manager::unreg (watcher &w, io_manager_vec<watcher> &queue) |
213 |
{ |
214 |
if (!iom_valid) |
215 |
return; |
216 |
|
217 |
if (w.active) |
218 |
{ |
219 |
queue [w.active - 1] = 0; |
220 |
w.active = 0; |
221 |
} |
222 |
} |
223 |
|
224 |
#if IOM_TIME |
225 |
void time_watcher::trigger () |
226 |
{ |
227 |
call (*this); |
228 |
io_manager::reg (*this); |
229 |
} |
230 |
|
231 |
void io_manager::reg (time_watcher &w) { io_manager::reg (w, tw); } |
232 |
void io_manager::unreg (time_watcher &w) { io_manager::unreg (w, tw); } |
233 |
#endif |
234 |
|
235 |
#if IOM_IO |
236 |
void io_manager::reg (io_watcher &w) { io_manager::reg (w, iow); } |
237 |
void io_manager::unreg (io_watcher &w) { io_manager::unreg (w, iow); } |
238 |
#endif |
239 |
|
240 |
#if IOM_CHECK |
241 |
void io_manager::reg (check_watcher &w) { io_manager::reg (w, cw); } |
242 |
void io_manager::unreg (check_watcher &w) { io_manager::unreg (w, cw); } |
243 |
#endif |
244 |
|
245 |
#if IOM_IDLE |
246 |
void io_manager::reg (idle_watcher &w) { io_manager::reg (w, iw); } |
247 |
void io_manager::unreg (idle_watcher &w) { io_manager::unreg (w, iw); } |
248 |
#endif |
249 |
|
250 |
#if IOM_SIG |
251 |
static void |
252 |
sighandler (int signum) |
253 |
{ |
254 |
sw [signum - 1]->pending = true; |
255 |
|
256 |
// we use a pipe for signal notifications, as most current |
257 |
// OSes (Linux...) do not implement pselect correctly. ugh. |
258 |
char ch = signum; // actual content not used |
259 |
write (sigpipe[1], &ch, 1); |
260 |
} |
261 |
|
262 |
void io_manager::reg (sig_watcher &w) |
263 |
{ |
264 |
init::required (); |
265 |
|
266 |
assert (0 < w.signum); |
267 |
|
268 |
sw.reserve (w.signum); |
269 |
|
270 |
while (sw.size () < w.signum) // pathetic |
271 |
sw.push_back (0); |
272 |
|
273 |
sig_vec *&sv = sw[w.signum - 1]; |
274 |
|
275 |
if (!sv) |
276 |
{ |
277 |
sv = new sig_vec; |
278 |
|
279 |
sigaddset (&sigs, w.signum); |
280 |
sigprocmask (SIG_BLOCK, &sigs, NULL); |
281 |
|
282 |
struct sigaction sa; |
283 |
sa.sa_handler = sighandler; |
284 |
sigfillset (&sa.sa_mask); |
285 |
sa.sa_flags = SA_RESTART; |
286 |
|
287 |
if (sigaction (w.signum, &sa, 0)) |
288 |
{ |
289 |
perror ("io_manager: error while installing signal handler, ignoring."); |
290 |
abort (); |
291 |
} |
292 |
|
293 |
} |
294 |
|
295 |
io_manager::reg (w, *sv); |
296 |
} |
297 |
|
298 |
void io_manager::unreg (sig_watcher &w) |
299 |
{ |
300 |
if (!w.active || !iom_valid) |
301 |
return; |
302 |
|
303 |
assert (0 < w.signum && w.signum <= sw.size ()); |
304 |
|
305 |
io_manager::unreg (w, *sw[w.signum - 1]); |
306 |
} |
307 |
|
308 |
void sig_watcher::start (int signum) |
309 |
{ |
310 |
stop (); |
311 |
this->signum = signum; |
312 |
io_manager::reg (*this); |
313 |
} |
314 |
#endif |
315 |
|
316 |
#if IOM_CHILD |
317 |
void io_manager::reg (child_watcher &w) { io_manager::reg (w, pw); } |
318 |
void io_manager::unreg (child_watcher &w) { io_manager::unreg (w, pw); } |
319 |
#endif |
320 |
|
321 |
void io_manager::loop () |
322 |
{ |
323 |
init::required (); |
324 |
|
325 |
#if IOM_TIME |
326 |
set_now (); |
327 |
#endif |
328 |
|
329 |
for (;;) |
330 |
{ |
331 |
|
332 |
#if IOM_TIME |
333 |
// call pending time watchers |
334 |
{ |
335 |
bool activity; |
336 |
|
337 |
do |
338 |
{ |
339 |
activity = false; |
340 |
|
341 |
for (int i = tw.size (); i--; ) |
342 |
if (!tw[i]) |
343 |
tw.erase_unordered (i); |
344 |
else if (tw[i]->at <= NOW) |
345 |
{ |
346 |
time_watcher &w = *tw[i]; |
347 |
|
348 |
unreg (w); |
349 |
w.call (w); |
350 |
|
351 |
activity = true; |
352 |
} |
353 |
} |
354 |
while (activity); |
355 |
} |
356 |
#endif |
357 |
|
358 |
#if IOM_CHECK |
359 |
// call all check watchers |
360 |
for (int i = cw.size (); i--; ) |
361 |
if (!cw[i]) |
362 |
cw.erase_unordered (i); |
363 |
else |
364 |
cw[i]->call (*cw[i]); |
365 |
#endif |
366 |
|
367 |
struct TIMEVAL *to = 0; |
368 |
struct TIMEVAL tval; |
369 |
|
370 |
#if IOM_IDLE |
371 |
if (iw.size ()) |
372 |
{ |
373 |
tval.tv_sec = 0; |
374 |
tval.TV_FRAC = 0; |
375 |
to = &tval; |
376 |
} |
377 |
else |
378 |
#endif |
379 |
{ |
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 |
399 |
fd_set rfd, wfd; |
400 |
|
401 |
FD_ZERO (&rfd); |
402 |
FD_ZERO (&wfd); |
403 |
|
404 |
int fds = 0; |
405 |
|
406 |
# if IOM_IO |
407 |
for (io_manager_vec<io_watcher>::const_iterator i = iow.end (); i-- > iow.begin (); ) |
408 |
if (*i) |
409 |
{ |
410 |
if ((*i)->events & EVENT_READ ) FD_SET ((*i)->fd, &rfd); |
411 |
if ((*i)->events & EVENT_WRITE) FD_SET ((*i)->fd, &wfd); |
412 |
|
413 |
if ((*i)->fd >= fds) fds = (*i)->fd + 1; |
414 |
} |
415 |
# endif |
416 |
|
417 |
if (!to && !fds) //TODO: also check idle_watchers and check_watchers? |
418 |
break; // no events |
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 |
430 |
fds = select (fds, &rfd, &wfd, NULL, to); |
431 |
# if IOM_SIG |
432 |
sigprocmask (SIG_BLOCK, &sigs, NULL); |
433 |
# endif |
434 |
|
435 |
# if IOM_TIME |
436 |
{ |
437 |
// update time, try to compensate for gross non-monotonic time changes |
438 |
tstamp diff = 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 |
} |
447 |
# endif |
448 |
|
449 |
if (fds > 0) |
450 |
{ |
451 |
# if IOM_SIG |
452 |
if (FD_ISSET (sigpipe[0], &rfd)) |
453 |
{ |
454 |
char ch; |
455 |
|
456 |
while (read (sigpipe[0], &ch, 1) > 0) |
457 |
; |
458 |
|
459 |
for (vector<sig_vec *>::iterator svp = sw.end (); svp-- > sw.begin (); ) |
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 |
} |
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 |
} |
491 |
else if (fds < 0 && errno != EINTR) |
492 |
{ |
493 |
perror ("io_manager: fatal error while waiting for I/O or time event, aborting."); |
494 |
abort (); |
495 |
} |
496 |
#if IOM_IDLE |
497 |
else |
498 |
for (int i = iw.size (); i--; ) |
499 |
if (!iw[i]) |
500 |
iw.erase_unordered (i); |
501 |
else |
502 |
iw[i]->call (*iw[i]); |
503 |
#endif |
504 |
|
505 |
#elif IOM_TIME |
506 |
if (!to) |
507 |
break; |
508 |
|
509 |
select (0, 0, 0, 0, &to); |
510 |
set_now (); |
511 |
#else |
512 |
break; |
513 |
#endif |
514 |
} |
515 |
} |
516 |
|