2 * UCW Library -- Main Loop
4 * (c) 2004--2010 Martin Mares <mj@ucw.cz>
6 * This software may be freely distributed and used according to the terms
7 * of the GNU Lesser General Public License.
14 #include "ucw/mainloop.h"
15 #include "ucw/threads.h"
30 #define MAIN_TIMER_LESS(x,y) ((x)->expires < (y)->expires)
31 #define MAIN_TIMER_SWAP(heap,a,b,t) (t=heap[a], heap[a]=heap[b], heap[b]=t, heap[a]->index=(a), heap[b]->index=(b))
33 // FIXME: Delivery of signals to threads?
34 static uns main_sigchld_set_up;
35 static volatile sig_atomic_t chld_received = 0;
38 // On recent Linux systems, O_CLOEXEC flag is available and we can get around
39 // the race condition of poll().
41 static int sig_pipe_recv, sig_pipe_send;
45 do_main_get_time(struct main_context *m)
48 gettimeofday(&tv, NULL);
49 m->now_seconds = tv.tv_sec;
50 m->now = (timestamp_t)tv.tv_sec * 1000 + tv.tv_usec / 1000;
56 struct main_context *m = xmalloc_zero(sizeof(*m));
58 DBG("MAIN: New context");
59 clist_init(&m->file_list);
60 clist_init(&m->hook_list);
61 clist_init(&m->hook_done_list);
62 clist_init(&m->process_list);
63 m->poll_table_obsolete = 1;
70 main_delete(struct main_context *m)
72 ASSERT(clist_empty(&m->file_list));
73 ASSERT(clist_empty(&m->hook_list));
74 ASSERT(clist_empty(&m->hook_done_list));
75 ASSERT(clist_empty(&m->process_list));
77 GARY_FREE(m->timer_table);
80 // FIXME: Some mechanism for cleaning up after fork()
84 main_switch_context(struct main_context *m)
86 struct ucwlib_context *c = ucwlib_thread_context();
87 struct main_context *m0 = c->main_context;
95 struct ucwlib_context *c = ucwlib_thread_context();
96 struct main_context *m = c->main_context;
104 struct main_context *m = main_switch_context(main_new());
111 struct main_context *m = main_switch_context(NULL);
118 do_main_get_time(main_current());
122 count_timers(struct main_context *m)
124 return GARY_SIZE(m->timer_table) - 1;
128 timer_add(struct main_timer *tm, timestamp_t expires)
130 struct main_context *m = main_current();
134 GARY_INIT(m->timer_table, 1);
135 m->timer_table[0] = NULL;
139 DBG("MAIN: Setting timer %p (expire at now+%lld)", tm, (long long)(expires - m->now));
141 DBG("MAIN: Clearing timer %p", tm);
142 uns num_timers = count_timers(m);
143 if (tm->expires < expires)
147 tm->expires = expires;
148 tm->index = num_timers + 1;
149 *GARY_PUSH(m->timer_table, 1) = tm;
150 HEAP_INSERT(struct main_timer *, m->timer_table, tm->index, MAIN_TIMER_LESS, MAIN_TIMER_SWAP);
154 tm->expires = expires;
155 HEAP_INCREASE(struct main_timer *, m->timer_table, num_timers, MAIN_TIMER_LESS, MAIN_TIMER_SWAP, tm->index);
158 else if (tm->expires > expires)
162 ASSERT(tm->index && tm->index <= num_timers);
163 HEAP_DELETE(struct main_timer *, m->timer_table, num_timers, MAIN_TIMER_LESS, MAIN_TIMER_SWAP, tm->index);
166 GARY_POP(m->timer_table, 1);
170 tm->expires = expires;
171 HEAP_DECREASE(struct main_timer *, m->timer_table, num_timers, MAIN_TIMER_LESS, MAIN_TIMER_SWAP, tm->index);
177 timer_del(struct main_timer *tm)
183 file_timer_expired(struct main_timer *tm)
185 struct main_file *fi = tm->data;
186 timer_del(&fi->timer);
187 if (fi->error_handler)
188 fi->error_handler(fi, MFERR_TIMEOUT);
192 file_add(struct main_file *fi)
194 struct main_context *m = main_current();
196 DBG("MAIN: Adding file %p (fd=%d)", fi, fi->fd);
198 clist_add_tail(&m->file_list, &fi->n);
199 fi->timer.handler = file_timer_expired;
202 m->poll_table_obsolete = 1;
203 if (fcntl(fi->fd, F_SETFL, O_NONBLOCK) < 0)
204 msg(L_ERROR, "Error setting fd %d to non-blocking mode: %m. Keep fingers crossed.", fi->fd);
208 file_chg(struct main_file *fi)
210 struct pollfd *p = fi->pollfd;
214 if (fi->read_handler)
215 p->events |= POLLIN | POLLHUP | POLLERR;
216 if (fi->write_handler)
217 p->events |= POLLOUT | POLLERR;
222 file_del(struct main_file *fi)
224 struct main_context *m = main_current();
226 DBG("MAIN: Deleting file %p (fd=%d)", fi, fi->fd);
228 timer_del(&fi->timer);
229 clist_remove(&fi->n);
231 m->poll_table_obsolete = 1;
232 fi->n.next = fi->n.prev = NULL;
236 file_read_handler(struct main_file *fi)
238 while (fi->rpos < fi->rlen)
240 int l = read(fi->fd, fi->rbuf + fi->rpos, fi->rlen - fi->rpos);
241 DBG("MAIN: FD %d: read %d", fi->fd, l);
244 if (errno != EINTR && errno != EAGAIN && fi->error_handler)
245 fi->error_handler(fi, MFERR_READ);
252 DBG("MAIN: FD %d done read %d of %d", fi->fd, fi->rpos, fi->rlen);
253 fi->read_handler = NULL;
260 file_write_handler(struct main_file *fi)
262 while (fi->wpos < fi->wlen)
264 int l = write(fi->fd, fi->wbuf + fi->wpos, fi->wlen - fi->wpos);
265 DBG("MAIN: FD %d: write %d", fi->fd, l);
268 if (errno != EINTR && errno != EAGAIN && fi->error_handler)
269 fi->error_handler(fi, MFERR_WRITE);
274 DBG("MAIN: FD %d done write %d", fi->fd, fi->wpos);
275 fi->write_handler = NULL;
282 file_read(struct main_file *fi, void *buf, uns len)
287 fi->read_handler = file_read_handler;
294 fi->read_handler = NULL;
296 fi->rpos = fi->rlen = 0;
302 file_write(struct main_file *fi, void *buf, uns len)
307 fi->write_handler = file_write_handler;
314 fi->write_handler = NULL;
316 fi->wpos = fi->wlen = 0;
322 file_set_timeout(struct main_file *fi, timestamp_t expires)
325 timer_add(&fi->timer, expires);
331 struct main_context *m = main_current();
333 CLIST_FOR_EACH(struct main_file *, f, m->file_list)
338 hook_add(struct main_hook *ho)
340 struct main_context *m = main_current();
342 DBG("MAIN: Adding hook %p", ho);
344 clist_add_tail(&m->hook_list, &ho->n);
348 hook_del(struct main_hook *ho)
350 DBG("MAIN: Deleting hook %p", ho);
352 clist_remove(&ho->n);
353 ho->n.next = ho->n.prev = NULL;
358 main_sigchld_handler(int x UNUSED)
360 int old_errno = errno;
361 DBG("SIGCHLD received");
364 while((result = write(sig_pipe_send, "c", 1)) == -1 && errno == EINTR);
365 if(result == -1 && errno != EAGAIN)
366 msg(L_SIGHANDLER|L_ERROR, "Could not write to self-pipe: %m");
371 dummy_read_handler(struct main_file *mp)
374 ssize_t result = read(mp->fd, buffer, 1024);
375 if(result == -1 && errno != EAGAIN)
376 msg(L_ERROR, "Could not read from selfpipe: %m");
378 return result == 1024;
382 pipe_configure(int fd)
385 if((flags = fcntl(fd, F_GETFL)) == -1 || fcntl(fd, F_SETFL, flags|O_NONBLOCK))
386 die("Could not set file descriptor %d to non-blocking: %m", fd);
387 if((flags = fcntl(fd, F_GETFD)) == -1 || fcntl(fd, F_SETFD, flags|O_CLOEXEC))
388 die("Could not set file descriptor %d to close-on-exec: %m", fd);
392 main_sigchld_handler(int x UNUSED)
394 DBG("SIGCHLD received");
399 process_add(struct main_process *mp)
401 struct main_context *m = main_current();
403 DBG("MAIN: Adding process %p (pid=%d)", mp, mp->pid);
406 clist_add_tail(&m->process_list, &mp->n);
407 if (!main_sigchld_set_up)
411 if(pipe(pipe_result) == -1)
412 die("Could not create selfpipe:%m");
413 pipe_configure(pipe_result[0]);
414 pipe_configure(pipe_result[1]);
415 sig_pipe_recv = pipe_result[0];
416 sig_pipe_send = pipe_result[1];
417 static struct main_file self_pipe;
418 self_pipe = (struct main_file) {
420 .read_handler = dummy_read_handler
422 file_add(&self_pipe);
425 bzero(&sa, sizeof(sa));
426 sa.sa_handler = main_sigchld_handler;
427 sa.sa_flags = SA_NOCLDSTOP | SA_RESTART;
428 sigaction(SIGCHLD, &sa, NULL);
429 main_sigchld_set_up = 1;
430 chld_received = 1; // The signal may have come before the handler
435 process_del(struct main_process *mp)
437 DBG("MAIN: Deleting process %p (pid=%d)", mp, mp->pid);
439 clist_remove(&mp->n);
444 process_fork(struct main_process *mp)
449 DBG("MAIN: Fork failed");
451 format_exit_status(mp->status_msg, -1);
459 DBG("MAIN: Forked process %d", (int) pid);
467 main_debug_context(struct main_context *m UNUSED)
470 msg(L_DEBUG, "### Main loop status on %lld", (long long) m->now);
471 msg(L_DEBUG, "\tActive timers:");
472 uns num_timers = count_timers(m);
473 for (uns i = 1; i <= num_timers; i++)
475 struct main_timer *tm = m->timer_table[i];
476 msg(L_DEBUG, "\t\t%p (expires %lld, data %p)", tm, (long long)(tm->expires ? tm->expires - m->now : 999999), tm->data);
478 struct main_file *fi;
479 msg(L_DEBUG, "\tActive files:");
480 CLIST_WALK(fi, m->file_list)
481 msg(L_DEBUG, "\t\t%p (fd %d, rh %p, wh %p, eh %p, expires %lld, data %p)",
482 fi, fi->fd, fi->read_handler, fi->write_handler, fi->error_handler,
483 (long long)(fi->timer.expires ? fi->timer.expires - m->now : 999999), fi->data);
484 msg(L_DEBUG, "\tActive hooks:");
485 struct main_hook *ho;
486 CLIST_WALK(ho, m->hook_done_list)
487 msg(L_DEBUG, "\t\t%p (func %p, data %p)", ho, ho->handler, ho->data);
488 CLIST_WALK(ho, m->hook_list)
489 msg(L_DEBUG, "\t\t%p (func %p, data %p)", ho, ho->handler, ho->data);
490 msg(L_DEBUG, "\tActive processes:");
491 struct main_process *pr;
492 CLIST_WALK(pr, m->process_list)
493 msg(L_DEBUG, "\t\t%p (pid %d, data %p)", pr, pr->pid, pr->data);
498 main_rebuild_poll_table(struct main_context *m)
500 struct main_file *fi;
501 if (m->poll_table_size < m->file_cnt)
504 xfree(m->poll_table);
506 m->poll_table_size = 1;
507 while (m->poll_table_size < m->file_cnt)
508 m->poll_table_size *= 2;
509 m->poll_table = xmalloc(sizeof(struct pollfd) * m->poll_table_size);
511 struct pollfd *p = m->poll_table;
512 DBG("MAIN: Rebuilding poll table: %d of %d entries set", m->file_cnt, m->poll_table_size);
513 CLIST_WALK(fi, m->file_list)
519 m->poll_table_obsolete = 0;
525 DBG("MAIN: Entering main_loop");
526 struct main_context *m = main_current();
528 struct main_file *fi;
529 struct main_hook *ho;
530 struct main_timer *tm;
531 struct main_process *pr;
536 timestamp_t wake = m->now + 1000000000;
537 while (GARY_SIZE(m->timer_table) > 1 && (tm = m->timer_table[1])->expires <= m->now)
539 DBG("MAIN: Timer %p expired at now-%lld", tm, (long long)(m->now - tm->expires));
542 int hook_min = HOOK_RETRY;
543 int hook_max = HOOK_SHUTDOWN;
544 while (ho = clist_remove_head(&m->hook_list))
546 clist_add_tail(&m->hook_done_list, &ho->n);
547 DBG("MAIN: Hook %p", ho);
548 int ret = ho->handler(ho);
549 hook_min = MIN(hook_min, ret);
550 hook_max = MAX(hook_max, ret);
552 clist_move(&m->hook_list, &m->hook_done_list);
553 if (hook_min == HOOK_SHUTDOWN ||
554 hook_min == HOOK_DONE && hook_max == HOOK_DONE ||
557 DBG("MAIN: Shut down by %s", m->shutdown ? "main_shutdown" : "a hook");
560 if (hook_max == HOOK_RETRY)
562 if (m->poll_table_obsolete)
563 main_rebuild_poll_table(m);
564 #ifndef USE_SELF_PIPE
565 // We don't have a reliable flag without the self-pipe.
568 if (chld_received && !clist_empty(&m->process_list))
572 wake = MIN(wake, m->now + 10000);
574 while ((pid = waitpid(-1, &stat, WNOHANG)) > 0)
576 DBG("MAIN: Child %d exited with status %x", pid, stat);
577 CLIST_WALK(pr, m->process_list)
582 format_exit_status(pr->status_msg, pr->status);
583 DBG("MAIN: Calling process exit handler");
590 if (count_timers(m) && (tm = m->timer_table[1])->expires < wake)
593 int timeout = ((wake > m->now) ? wake - m->now : 0);
594 DBG("MAIN: Poll for %d fds and timeout %d ms", m->file_cnt, timeout);
595 int p = poll(m->poll_table, m->file_cnt, timeout);
596 timestamp_t old_now = m->now;
598 m->idle_time += m->now - old_now;
601 struct pollfd *p = m->poll_table;
602 CLIST_WALK(fi, m->file_list)
604 if (p->revents & (POLLIN | POLLHUP | POLLERR))
607 DBG("MAIN: Read event on fd %d", p->fd);
608 while (fi->read_handler && fi->read_handler(fi) && !m->poll_table_obsolete);
609 if (m->poll_table_obsolete) /* File entries have been inserted or deleted => better not risk continuing to nowhere */
612 if (p->revents & (POLLOUT | POLLERR))
615 DBG("MAIN: Write event on fd %d", p->fd);
616 while (fi->write_handler && fi->write_handler(fi) && !m->poll_table_obsolete);
617 if (m->poll_table_obsolete)
628 static struct main_process mp;
629 static struct main_file fin, fout;
630 static struct main_hook hook;
631 static struct main_timer tm;
635 static void dread(struct main_file *fi)
637 if (fi->rpos < fi->rlen)
639 msg(L_INFO, "Read EOF");
644 msg(L_INFO, "Read done");
645 file_read(fi, rb, sizeof(rb));
649 static void derror(struct main_file *fi, int cause)
651 msg(L_INFO, "Error: %m !!! (cause %d)", cause);
655 static void dwrite(struct main_file *fi UNUSED)
657 msg(L_INFO, "Write done");
660 static int dhook(struct main_hook *ho UNUSED)
662 msg(L_INFO, "Hook called");
666 static void dtimer(struct main_timer *tm)
668 msg(L_INFO, "Timer tick");
669 timer_add(tm, main_get_now() + 10000);
672 static void dentry(void)
674 msg(L_INFO, "*** SUBPROCESS START ***");
676 msg(L_INFO, "*** SUBPROCESS FINISH ***");
680 static void dexit(struct main_process *pr)
682 msg(L_INFO, "Subprocess %d exited with status %x", pr->pid, pr->status);
692 fin.read_done = dread;
693 fin.error_handler = derror;
695 file_read(&fin, rb, sizeof(rb));
698 fout.write_done = dwrite;
699 fout.error_handler = derror;
701 file_write(&fout, "Hello, world!\n", 14);
703 hook.handler = dhook;
707 timer_add(&tm, main_get_now() + 1000);
710 if (!process_fork(&mp))
716 msg(L_INFO, "Finished.");