| 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 |
#ifndef IOM_LIBEVENT |
| 55 |
#if IOM_IO |
| 56 |
static io_manager_vec<io_watcher> iow; |
| 57 |
#endif |
| 58 |
#if IOM_TIME |
| 59 |
static io_manager_vec<time_watcher> tw; |
| 60 |
#endif |
| 61 |
#endif |
| 62 |
|
| 63 |
#if IOM_CHECK |
| 64 |
static io_manager_vec<check_watcher> cw; |
| 65 |
#endif |
| 66 |
#if IOM_IDLE |
| 67 |
static io_manager_vec<idle_watcher> iw; |
| 68 |
#endif |
| 69 |
|
| 70 |
#if IOM_SIG |
| 71 |
static int sigpipe[2]; // signal signalling pipe |
| 72 |
static sigset_t sigs; |
| 73 |
struct sig_vec : io_manager_vec<sig_watcher> { |
| 74 |
int pending; |
| 75 |
sig_vec () |
| 76 |
: pending (false) |
| 77 |
{ } |
| 78 |
}; |
| 79 |
static vector<sig_vec *> sw; |
| 80 |
#endif |
| 81 |
|
| 82 |
#if IOM_CHILD |
| 83 |
static io_manager_vec<child_watcher> pw; |
| 84 |
#endif |
| 85 |
|
| 86 |
// this is a dummy time watcher to ensure that the first |
| 87 |
// time watcher is _always_ valid, this gets rid of a lot |
| 88 |
// of null-pointer-checks |
| 89 |
// (must come _before_ iom is being defined) |
| 90 |
static struct tw0 : time_watcher |
| 91 |
{ |
| 92 |
void cb (time_watcher &w) |
| 93 |
{ |
| 94 |
// should never get called |
| 95 |
// reached end-of-time, or tstamp has a bogus definition, |
| 96 |
// or compiler initialisation order broken, or something else :) |
| 97 |
abort (); |
| 98 |
} |
| 99 |
|
| 100 |
tw0 () |
| 101 |
: time_watcher (this, &tw0::cb) |
| 102 |
{ } |
| 103 |
} tw0; |
| 104 |
|
| 105 |
tstamp NOW; |
| 106 |
|
| 107 |
#if IOM_CHILD |
| 108 |
// sig_watcher for child signal(s) |
| 109 |
static struct sw0 : sig_watcher |
| 110 |
{ |
| 111 |
void cb (sig_watcher &w) |
| 112 |
{ |
| 113 |
// SIGCHLD, call corresponding watchera |
| 114 |
pid_t pid; |
| 115 |
int status; |
| 116 |
|
| 117 |
while ((pid = waitpid (-1, &status, WNOHANG)) > 0) |
| 118 |
for (int i = pw.size (); i--; ) |
| 119 |
{ |
| 120 |
child_watcher *w = pw[i]; |
| 121 |
|
| 122 |
if (!w) |
| 123 |
pw.erase_unordered (i); |
| 124 |
else if (w->pid == pid) |
| 125 |
{ |
| 126 |
io_manager::unreg (*w); |
| 127 |
w->call (*w, status); |
| 128 |
} |
| 129 |
} |
| 130 |
} |
| 131 |
|
| 132 |
sw0 () |
| 133 |
: sig_watcher (this, &sw0::cb) |
| 134 |
{ } |
| 135 |
} sw0; |
| 136 |
#endif |
| 137 |
|
| 138 |
#if IOM_TIME |
| 139 |
tstamp io_manager::now () |
| 140 |
{ |
| 141 |
struct timeval tv; |
| 142 |
|
| 143 |
gettimeofday (&tv, 0); |
| 144 |
return (tstamp)tv.tv_sec + (tstamp)tv.tv_usec / 1000000.; |
| 145 |
} |
| 146 |
|
| 147 |
void io_manager::set_now () |
| 148 |
{ |
| 149 |
NOW = now (); |
| 150 |
} |
| 151 |
#endif |
| 152 |
|
| 153 |
static bool iom_valid; |
| 154 |
|
| 155 |
// used for initialisation only |
| 156 |
static struct init { |
| 157 |
init () |
| 158 |
{ |
| 159 |
#ifdef IOM_PREINIT |
| 160 |
{ IOM_PREINIT } |
| 161 |
#endif |
| 162 |
#ifdef IOM_LIBEVENT |
| 163 |
event_init (); |
| 164 |
#endif |
| 165 |
iom_valid = true; |
| 166 |
|
| 167 |
#if IOM_SIG |
| 168 |
sigemptyset (&sigs); |
| 169 |
|
| 170 |
if (pipe (sigpipe)) |
| 171 |
{ |
| 172 |
perror ("io_manager: unable to create signal pipe, aborting."); |
| 173 |
abort (); |
| 174 |
} |
| 175 |
|
| 176 |
fcntl (sigpipe[0], F_SETFL, O_NONBLOCK); fcntl (sigpipe[0], F_SETFD, FD_CLOEXEC); |
| 177 |
fcntl (sigpipe[1], F_SETFL, O_NONBLOCK); fcntl (sigpipe[1], F_SETFD, FD_CLOEXEC); |
| 178 |
#endif |
| 179 |
|
| 180 |
#if IOM_CHILD |
| 181 |
sw0.start (SIGCHLD); |
| 182 |
#endif |
| 183 |
|
| 184 |
#if IOM_TIME |
| 185 |
io_manager::set_now (); |
| 186 |
|
| 187 |
tw0.start (TSTAMP_MAX); |
| 188 |
#endif |
| 189 |
|
| 190 |
#ifdef IOM_POSTINIT |
| 191 |
{ IOM_POSTINIT } |
| 192 |
#endif |
| 193 |
} |
| 194 |
|
| 195 |
~init () |
| 196 |
{ |
| 197 |
iom_valid = false; |
| 198 |
} |
| 199 |
|
| 200 |
static void required (); |
| 201 |
} init; |
| 202 |
|
| 203 |
void |
| 204 |
init::required () |
| 205 |
{ |
| 206 |
if (!iom_valid) |
| 207 |
{ |
| 208 |
write (2, "io_manager: early registration attempt, aborting.\n", |
| 209 |
sizeof ("io_manager: early registration attempt, aborting.\n") - 1); |
| 210 |
abort (); |
| 211 |
} |
| 212 |
} |
| 213 |
|
| 214 |
template<class watcher> |
| 215 |
void io_manager::reg (watcher &w, io_manager_vec<watcher> &queue) |
| 216 |
{ |
| 217 |
init::required (); |
| 218 |
|
| 219 |
if (!w.active) |
| 220 |
{ |
| 221 |
queue.push_back (&w); |
| 222 |
w.active = queue.size (); |
| 223 |
} |
| 224 |
} |
| 225 |
|
| 226 |
template<class watcher> |
| 227 |
void io_manager::unreg (watcher &w, io_manager_vec<watcher> &queue) |
| 228 |
{ |
| 229 |
if (!iom_valid) |
| 230 |
return; |
| 231 |
|
| 232 |
if (w.active) |
| 233 |
{ |
| 234 |
queue [w.active - 1] = 0; |
| 235 |
w.active = 0; |
| 236 |
} |
| 237 |
} |
| 238 |
|
| 239 |
#if IOM_TIME |
| 240 |
# ifdef IOM_LIBEVENT |
| 241 |
void iom_time_c_callback (int fd, short events, void *data) |
| 242 |
{ |
| 243 |
time_watcher *w = static_cast<time_watcher *>(data); |
| 244 |
w->call (*w); |
| 245 |
} |
| 246 |
# else |
| 247 |
void io_manager::reg (time_watcher &w) { io_manager::reg (w, tw); } |
| 248 |
void io_manager::unreg (time_watcher &w) { io_manager::unreg (w, tw); } |
| 249 |
# endif |
| 250 |
|
| 251 |
void time_watcher::trigger () |
| 252 |
{ |
| 253 |
call (*this); |
| 254 |
start (); |
| 255 |
} |
| 256 |
#endif |
| 257 |
|
| 258 |
#if IOM_IO |
| 259 |
# ifdef IOM_LIBEVENT |
| 260 |
void iom_io_c_callback (int fd, short events, void *data) |
| 261 |
{ |
| 262 |
io_watcher *w = static_cast<io_watcher *>(data); |
| 263 |
w->call (*w, events); |
| 264 |
} |
| 265 |
# else |
| 266 |
void io_manager::reg (io_watcher &w) { io_manager::reg (w, iow); } |
| 267 |
void io_manager::unreg (io_watcher &w) { io_manager::unreg (w, iow); } |
| 268 |
# endif |
| 269 |
#endif |
| 270 |
|
| 271 |
#if IOM_CHECK |
| 272 |
void io_manager::reg (check_watcher &w) { io_manager::reg (w, cw); } |
| 273 |
void io_manager::unreg (check_watcher &w) { io_manager::unreg (w, cw); } |
| 274 |
#endif |
| 275 |
|
| 276 |
#if IOM_IDLE |
| 277 |
void io_manager::reg (idle_watcher &w) { io_manager::reg (w, iw); } |
| 278 |
void io_manager::unreg (idle_watcher &w) { io_manager::unreg (w, iw); } |
| 279 |
#endif |
| 280 |
|
| 281 |
#if IOM_SIG |
| 282 |
static void |
| 283 |
sighandler (int signum) |
| 284 |
{ |
| 285 |
sw [signum - 1]->pending = true; |
| 286 |
|
| 287 |
// we use a pipe for signal notifications, as most current |
| 288 |
// OSes (Linux...) do not implement pselect correctly. ugh. |
| 289 |
char ch = signum; // actual content not used |
| 290 |
write (sigpipe[1], &ch, 1); |
| 291 |
} |
| 292 |
|
| 293 |
void io_manager::reg (sig_watcher &w) |
| 294 |
{ |
| 295 |
init::required (); |
| 296 |
|
| 297 |
assert (0 < w.signum); |
| 298 |
|
| 299 |
sw.reserve (w.signum); |
| 300 |
|
| 301 |
while (sw.size () < w.signum) // pathetic |
| 302 |
sw.push_back (0); |
| 303 |
|
| 304 |
sig_vec *&sv = sw[w.signum - 1]; |
| 305 |
|
| 306 |
if (!sv) |
| 307 |
{ |
| 308 |
sv = new sig_vec; |
| 309 |
|
| 310 |
sigaddset (&sigs, w.signum); |
| 311 |
sigprocmask (SIG_BLOCK, &sigs, NULL); |
| 312 |
|
| 313 |
struct sigaction sa; |
| 314 |
sa.sa_handler = sighandler; |
| 315 |
sigfillset (&sa.sa_mask); |
| 316 |
sa.sa_flags = SA_RESTART; |
| 317 |
|
| 318 |
if (sigaction (w.signum, &sa, 0)) |
| 319 |
{ |
| 320 |
perror ("io_manager: error while installing signal handler, ignoring."); |
| 321 |
abort (); |
| 322 |
} |
| 323 |
|
| 324 |
} |
| 325 |
|
| 326 |
io_manager::reg (w, *sv); |
| 327 |
} |
| 328 |
|
| 329 |
void io_manager::unreg (sig_watcher &w) |
| 330 |
{ |
| 331 |
if (!w.active || !iom_valid) |
| 332 |
return; |
| 333 |
|
| 334 |
assert (0 < w.signum && w.signum <= sw.size ()); |
| 335 |
|
| 336 |
io_manager::unreg (w, *sw[w.signum - 1]); |
| 337 |
} |
| 338 |
|
| 339 |
void sig_watcher::start (int signum) |
| 340 |
{ |
| 341 |
stop (); |
| 342 |
this->signum = signum; |
| 343 |
io_manager::reg (*this); |
| 344 |
} |
| 345 |
#endif |
| 346 |
|
| 347 |
#if IOM_CHILD |
| 348 |
void io_manager::reg (child_watcher &w) { io_manager::reg (w, pw); } |
| 349 |
void io_manager::unreg (child_watcher &w) { io_manager::unreg (w, pw); } |
| 350 |
#endif |
| 351 |
|
| 352 |
void io_manager::loop () |
| 353 |
{ |
| 354 |
init::required (); |
| 355 |
|
| 356 |
#if IOM_TIME |
| 357 |
set_now (); |
| 358 |
#endif |
| 359 |
|
| 360 |
for (;;) |
| 361 |
{ |
| 362 |
#ifndef IOM_LIBEVENT |
| 363 |
#if IOM_TIME |
| 364 |
// call pending time watchers |
| 365 |
{ |
| 366 |
bool activity; |
| 367 |
|
| 368 |
do |
| 369 |
{ |
| 370 |
activity = false; |
| 371 |
|
| 372 |
for (int i = tw.size (); i--; ) |
| 373 |
if (!tw[i]) |
| 374 |
tw.erase_unordered (i); |
| 375 |
else if (tw[i]->at <= NOW) |
| 376 |
{ |
| 377 |
time_watcher &w = *tw[i]; |
| 378 |
|
| 379 |
unreg (w); |
| 380 |
w.call (w); |
| 381 |
|
| 382 |
activity = true; |
| 383 |
} |
| 384 |
} |
| 385 |
while (activity); |
| 386 |
} |
| 387 |
#endif |
| 388 |
#endif |
| 389 |
|
| 390 |
#if IOM_CHECK |
| 391 |
// call all check watchers |
| 392 |
for (int i = cw.size (); i--; ) |
| 393 |
if (!cw[i]) |
| 394 |
cw.erase_unordered (i); |
| 395 |
else |
| 396 |
cw[i]->call (*cw[i]); |
| 397 |
#endif |
| 398 |
|
| 399 |
struct TIMEVAL *to = 0; |
| 400 |
struct TIMEVAL tval; |
| 401 |
|
| 402 |
#if IOM_IDLE |
| 403 |
if (iw.size ()) |
| 404 |
{ |
| 405 |
tval.tv_sec = 0; |
| 406 |
tval.TV_FRAC = 0; |
| 407 |
to = &tval; |
| 408 |
} |
| 409 |
else |
| 410 |
#endif |
| 411 |
#ifndef IOM_LIBEVENT |
| 412 |
{ |
| 413 |
#if IOM_TIME |
| 414 |
// find earliest active watcher |
| 415 |
time_watcher *next = tw[0]; // the first time-watcher must exist at ALL times |
| 416 |
|
| 417 |
for (io_manager_vec<time_watcher>::const_iterator i = tw.end (); i-- > tw.begin (); ) |
| 418 |
if (*i && (*i)->at < next->at) |
| 419 |
next = *i; |
| 420 |
|
| 421 |
if (next->at > NOW && next != tw[0]) |
| 422 |
{ |
| 423 |
double diff = next->at - NOW; |
| 424 |
tval.tv_sec = (int)diff; |
| 425 |
tval.TV_FRAC = (int) ((diff - tval.tv_sec) * TV_MULT); |
| 426 |
to = &tval; |
| 427 |
} |
| 428 |
#endif |
| 429 |
} |
| 430 |
|
| 431 |
#if IOM_IO || IOM_SIG |
| 432 |
fd_set rfd, wfd; |
| 433 |
|
| 434 |
FD_ZERO (&rfd); |
| 435 |
FD_ZERO (&wfd); |
| 436 |
|
| 437 |
int fds = 0; |
| 438 |
|
| 439 |
#if IOM_IO |
| 440 |
for (io_manager_vec<io_watcher>::const_iterator i = iow.end (); i-- > iow.begin (); ) |
| 441 |
if (*i) |
| 442 |
{ |
| 443 |
if ((*i)->events & EVENT_READ ) FD_SET ((*i)->fd, &rfd); |
| 444 |
if ((*i)->events & EVENT_WRITE) FD_SET ((*i)->fd, &wfd); |
| 445 |
|
| 446 |
if ((*i)->fd >= fds) fds = (*i)->fd + 1; |
| 447 |
} |
| 448 |
#endif |
| 449 |
|
| 450 |
if (!to && !fds) //TODO: also check idle_watchers and check_watchers? |
| 451 |
break; // no events |
| 452 |
|
| 453 |
#if IOM_SIG |
| 454 |
FD_SET (sigpipe[0], &rfd); |
| 455 |
if (sigpipe[0] >= fds) fds = sigpipe[0] + 1; |
| 456 |
#endif |
| 457 |
|
| 458 |
#if IOM_SIG |
| 459 |
// there is no race, as we use a pipe for signals, so select |
| 460 |
// will return if a signal is caught. |
| 461 |
sigprocmask (SIG_UNBLOCK, &sigs, NULL); |
| 462 |
#endif |
| 463 |
fds = select (fds, &rfd, &wfd, NULL, to); |
| 464 |
#if IOM_SIG |
| 465 |
sigprocmask (SIG_BLOCK, &sigs, NULL); |
| 466 |
#endif |
| 467 |
|
| 468 |
#else |
| 469 |
if (to) |
| 470 |
event_loop (EVLOOP_NONBLOCK); |
| 471 |
else |
| 472 |
event_loop (EVLOOP_ONCE); |
| 473 |
#endif |
| 474 |
|
| 475 |
#if IOM_TIME |
| 476 |
{ |
| 477 |
// update time, try to compensate for gross non-monotonic time changes |
| 478 |
tstamp diff = NOW; |
| 479 |
set_now (); |
| 480 |
diff = NOW - diff; |
| 481 |
|
| 482 |
if (diff < 0) |
| 483 |
for (io_manager_vec<time_watcher>::const_iterator i = tw.end (); i-- > tw.begin (); ) |
| 484 |
if (*i) |
| 485 |
(*i)->at += diff; |
| 486 |
} |
| 487 |
#endif |
| 488 |
|
| 489 |
#ifndef IOM_LIBEVENT |
| 490 |
if (fds > 0) |
| 491 |
{ |
| 492 |
#if IOM_SIG |
| 493 |
if (FD_ISSET (sigpipe[0], &rfd)) |
| 494 |
{ |
| 495 |
char ch; |
| 496 |
|
| 497 |
while (read (sigpipe[0], &ch, 1) > 0) |
| 498 |
; |
| 499 |
|
| 500 |
for (vector<sig_vec *>::iterator svp = sw.end (); svp-- > sw.begin (); ) |
| 501 |
if (*svp && (*svp)->pending) |
| 502 |
{ |
| 503 |
sig_vec &sv = **svp; |
| 504 |
for (int i = sv.size (); i--; ) |
| 505 |
if (!sv[i]) |
| 506 |
sv.erase_unordered (i); |
| 507 |
else |
| 508 |
sv[i]->call (*sv[i]); |
| 509 |
|
| 510 |
sv.pending = false; |
| 511 |
} |
| 512 |
} |
| 513 |
#endif |
| 514 |
|
| 515 |
#if IOM_IO |
| 516 |
for (int i = iow.size (); i--; ) |
| 517 |
if (!iow[i]) |
| 518 |
iow.erase_unordered (i); |
| 519 |
else |
| 520 |
{ |
| 521 |
io_watcher &w = *iow[i]; |
| 522 |
short revents = w.events; |
| 523 |
|
| 524 |
if (!FD_ISSET (w.fd, &rfd)) revents &= ~EVENT_READ; |
| 525 |
if (!FD_ISSET (w.fd, &wfd)) revents &= ~EVENT_WRITE; |
| 526 |
|
| 527 |
if (revents) |
| 528 |
w.call (w, revents); |
| 529 |
} |
| 530 |
#endif |
| 531 |
} |
| 532 |
else if (fds < 0 && errno != EINTR) |
| 533 |
{ |
| 534 |
perror ("io_manager: fatal error while waiting for I/O or time event, aborting."); |
| 535 |
abort (); |
| 536 |
} |
| 537 |
#else |
| 538 |
if (0) |
| 539 |
; |
| 540 |
#endif |
| 541 |
#if IOM_IDLE |
| 542 |
else |
| 543 |
for (int i = iw.size (); i--; ) |
| 544 |
if (!iw[i]) |
| 545 |
iw.erase_unordered (i); |
| 546 |
else |
| 547 |
iw[i]->call (*iw[i]); |
| 548 |
#endif |
| 549 |
|
| 550 |
#elif IOM_TIME |
| 551 |
if (!to) |
| 552 |
break; |
| 553 |
|
| 554 |
select (0, 0, 0, 0, to); |
| 555 |
set_now (); |
| 556 |
break; |
| 557 |
#endif |
| 558 |
} |
| 559 |
} |
| 560 |
|
