2 * UCW Library -- Main Loop
4 * (c) 2004--2011 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 #ifdef CONFIG_UCW_THREADS
32 #define THREAD_SIGMASK pthread_sigmask
34 #define THREAD_SIGMASK sigprocmask
37 #ifdef CONFIG_UCW_EPOLL
38 #include <sys/epoll.h>
41 #define MAIN_TIMER_LESS(x,y) ((x)->expires < (y)->expires)
42 #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))
44 #define EPOLL_BUF_SIZE 256
46 static void file_del_ctx(struct main_context *m, struct main_file *fi);
47 static void signal_del_ctx(struct main_context *m, struct main_signal *ms);
50 main_get_time_ctx(struct main_context *m)
53 gettimeofday(&tv, NULL);
54 m->now_seconds = tv.tv_sec;
55 m->now = (timestamp_t)tv.tv_sec * 1000 + tv.tv_usec / 1000;
58 static struct main_context *
59 main_current_nocheck(void)
61 return ucwlib_thread_context()->main_context;
67 struct main_context *m = main_current_nocheck();
73 main_is_current(struct main_context *m)
75 return (m == main_current_nocheck());
79 count_timers(struct main_context *m)
82 return GARY_SIZE(m->timer_table) - 1;
90 struct main_context *m = xmalloc_zero(sizeof(*m));
92 DBG("MAIN: New context");
93 clist_init(&m->file_list);
94 clist_init(&m->file_active_list);
95 clist_init(&m->hook_list);
96 clist_init(&m->hook_done_list);
97 clist_init(&m->process_list);
98 clist_init(&m->signal_list);
99 #ifdef CONFIG_UCW_EPOLL
100 m->epoll_fd = epoll_create(64);
102 die("epoll_create() failed: %m");
103 m->epoll_events = xmalloc(EPOLL_BUF_SIZE * sizeof(struct epoll_event *));
104 clist_init(&m->file_recalc_list);
106 m->poll_table_obsolete = 1;
108 main_get_time_ctx(m);
109 sigemptyset(&m->want_signals);
110 m->sig_pipe_recv = m->sig_pipe_send = -1;
116 main_prepare_delete(struct main_context *m)
119 * If the context is current, deactivate it first. But beware,
120 * we must not call functions that depend on the current context.
122 if (main_is_current(m))
123 main_switch_context(NULL);
125 // Close epoll descriptor early enough, it might be shared after fork!
126 #ifdef CONFIG_UCW_EPOLL
127 ASSERT(clist_empty(&m->file_recalc_list));
128 xfree(m->epoll_events);
132 GARY_FREE(m->poll_table);
133 GARY_FREE(m->poll_file_table);
136 if (m->sigchld_handler)
138 signal_del_ctx(m, m->sigchld_handler);
139 xfree(m->sigchld_handler);
141 if (m->sig_pipe_file)
143 file_del_ctx(m, m->sig_pipe_file);
144 xfree(m->sig_pipe_file);
146 if (m->sig_pipe_recv >= 0)
148 close(m->sig_pipe_recv);
149 close(m->sig_pipe_send);
154 main_do_delete(struct main_context *m)
156 GARY_FREE(m->timer_table);
161 main_delete(struct main_context *m)
166 main_prepare_delete(m);
167 ASSERT(clist_empty(&m->file_list));
168 ASSERT(clist_empty(&m->file_active_list));
169 ASSERT(clist_empty(&m->hook_list));
170 ASSERT(clist_empty(&m->hook_done_list));
171 ASSERT(clist_empty(&m->process_list));
172 ASSERT(clist_empty(&m->signal_list));
173 ASSERT(!count_timers(m));
178 main_destroy(struct main_context *m)
180 // FIXME: Add a doc note on calling from a running mainloop
183 main_prepare_delete(m);
186 clist_insert_list_after(&m->file_active_list, m->file_list.head.prev);
187 #ifdef CONFIG_UCW_EPOLL
188 clist_insert_list_after(&m->file_recalc_list, m->file_list.head.prev);
190 CLIST_FOR_EACH(struct main_file *, f, m->file_list)
196 struct main_context *
197 main_switch_context(struct main_context *m)
199 struct ucwlib_context *c = ucwlib_thread_context();
200 struct main_context *m0 = c->main_context;
203 * Not only we need to switch the signal sets of the two contexts,
204 * but it is also necessary to avoid invoking a signal handler
205 * in the middle of changing c->main_context.
207 if (m0 && !clist_empty(&m0->signal_list))
208 THREAD_SIGMASK(SIG_BLOCK, &m0->want_signals, NULL);
210 if (m && !clist_empty(&m->signal_list))
211 THREAD_SIGMASK(SIG_UNBLOCK, &m->want_signals, NULL);
219 struct main_context *m = main_switch_context(main_new());
226 main_delete(main_current_nocheck());
232 main_destroy(main_current_nocheck());
238 main_get_time_ctx(main_current());
242 timer_add(struct main_timer *tm, timestamp_t expires)
244 struct main_context *m = main_current();
248 GARY_INIT(m->timer_table, 1);
249 m->timer_table[0] = NULL;
253 DBG("MAIN: Setting timer %p (expire at now+%lld)", tm, (long long)(expires - m->now));
255 DBG("MAIN: Clearing timer %p", tm);
256 uns num_timers = count_timers(m);
257 if (tm->expires < expires)
261 tm->expires = expires;
262 tm->index = num_timers + 1;
263 *GARY_PUSH(m->timer_table, 1) = tm;
264 HEAP_INSERT(struct main_timer *, m->timer_table, tm->index, MAIN_TIMER_LESS, MAIN_TIMER_SWAP);
268 tm->expires = expires;
269 HEAP_INCREASE(struct main_timer *, m->timer_table, num_timers, MAIN_TIMER_LESS, MAIN_TIMER_SWAP, tm->index);
272 else if (tm->expires > expires)
276 ASSERT(tm->index && tm->index <= num_timers);
277 HEAP_DELETE(struct main_timer *, m->timer_table, num_timers, MAIN_TIMER_LESS, MAIN_TIMER_SWAP, tm->index);
280 GARY_POP(m->timer_table, 1);
284 tm->expires = expires;
285 HEAP_DECREASE(struct main_timer *, m->timer_table, num_timers, MAIN_TIMER_LESS, MAIN_TIMER_SWAP, tm->index);
291 timer_add_rel(struct main_timer *tm, timestamp_t expires_delta)
293 struct main_context *m = main_current();
294 return timer_add(tm, m->now + expires_delta);
298 timer_del(struct main_timer *tm)
304 file_want_events(struct main_file *fi)
307 if (fi->read_handler)
308 events |= POLLIN | POLLHUP | POLLERR;
309 if (fi->write_handler)
310 events |= POLLOUT | POLLERR;
315 file_add(struct main_file *fi)
317 struct main_context *m = main_current();
319 DBG("MAIN: Adding file %p (fd=%d)", fi, fi->fd);
320 ASSERT(!clist_is_linked(&fi->n));
321 clist_add_tail(&m->file_list, &fi->n);
323 #ifdef CONFIG_UCW_EPOLL
324 struct epoll_event evt = {
325 .events = file_want_events(fi),
328 if (epoll_ctl(m->epoll_fd, EPOLL_CTL_ADD, fi->fd, &evt) < 0)
329 die("epoll_ctl() failed: %m");
330 fi->last_want_events = evt.events;
332 m->poll_table_obsolete = 1;
334 if (fcntl(fi->fd, F_SETFL, O_NONBLOCK) < 0)
335 msg(L_ERROR, "Error setting fd %d to non-blocking mode: %m. Keep fingers crossed.", fi->fd);
339 file_chg(struct main_file *fi)
341 #ifdef CONFIG_UCW_EPOLL
342 clist_remove(&fi->n);
343 clist_add_tail(&main_current()->file_recalc_list, &fi->n);
345 struct pollfd *p = fi->pollfd;
347 p->events = file_want_events(fi);
352 file_del_ctx(struct main_context *m, struct main_file *fi)
354 // XXX: Can be called on a non-current context
355 DBG("MAIN: Deleting file %p (fd=%d)", fi, fi->fd);
357 ASSERT(clist_is_linked(&fi->n));
358 clist_unlink(&fi->n);
360 #ifdef CONFIG_UCW_EPOLL
361 if (m->epoll_fd >= 0 && epoll_ctl(m->epoll_fd, EPOLL_CTL_DEL, fi->fd, NULL) < 0)
362 die("epoll_ctl() failed: %m");
364 m->poll_table_obsolete = 1;
369 file_del(struct main_file *fi)
371 file_del_ctx(main_current(), fi);
375 hook_add(struct main_hook *ho)
377 struct main_context *m = main_current();
379 DBG("MAIN: Adding hook %p", ho);
380 ASSERT(!clist_is_linked(&ho->n));
381 clist_add_tail(&m->hook_list, &ho->n);
385 hook_del(struct main_hook *ho)
387 DBG("MAIN: Deleting hook %p", ho);
388 ASSERT(clist_is_linked(&ho->n));
389 clist_unlink(&ho->n);
393 sigchld_received(struct main_signal *sg UNUSED)
395 struct main_context *m = main_current();
399 while ((pid = waitpid(-1, &stat, WNOHANG)) > 0)
401 DBG("MAIN: Child %d exited with status %x", pid, stat);
402 CLIST_FOR_EACH(struct main_process *, pr, m->process_list)
407 format_exit_status(pr->status_msg, pr->status);
408 DBG("MAIN: Calling process exit handler");
416 process_add(struct main_process *mp)
418 struct main_context *m = main_current();
420 DBG("MAIN: Adding process %p (pid=%d)", mp, mp->pid);
421 ASSERT(!clist_is_linked(&mp->n));
423 clist_add_tail(&m->process_list, &mp->n);
424 if (!m->sigchld_handler)
426 struct main_signal *sg = xmalloc_zero(sizeof(*sg));
427 m->sigchld_handler = sg;
428 sg->signum = SIGCHLD;
429 sg->handler = sigchld_received;
435 process_del(struct main_process *mp)
437 DBG("MAIN: Deleting process %p (pid=%d)", mp, mp->pid);
438 ASSERT(clist_is_linked(&mp->n));
439 clist_unlink(&mp->n);
443 process_fork(struct main_process *mp)
448 DBG("MAIN: Fork failed");
450 format_exit_status(mp->status_msg, -1);
458 DBG("MAIN: Forked process %d", (int) pid);
466 pipe_read_handler(struct main_file *mf UNUSED)
468 struct main_context *m = main_current();
470 int n = read(m->sig_pipe_recv, &signum, sizeof(signum));
475 msg(L_ERROR, "Error reading signal pipe: %m");
478 ASSERT(n == sizeof(signum));
480 DBG("MAIN: Sigpipe: received signal %d", signum);
481 struct main_signal iter = { .signum = -1 };
482 struct main_signal *sg = clist_head(&m->signal_list);
485 if (sg->signum == signum)
487 DBG("MAIN: Sigpipe: invoking handler %p", sg);
488 clist_insert_after(&iter.n, &sg->n);
490 sg = clist_next(&m->signal_list, &iter.n);
491 clist_remove(&iter.n);
494 sg = clist_next(&m->signal_list, &sg->n);
501 pipe_configure(int fd)
504 if ((flags = fcntl(fd, F_GETFL)) < 0 || fcntl(fd, F_SETFL, flags|O_NONBLOCK) < 0)
505 die("Could not set file descriptor %d to non-blocking: %m", fd);
509 pipe_setup(struct main_context *m)
511 DBG("MAIN: Sigpipe: Setting up the pipe");
514 if (pipe(pipe_result) == -1)
515 die("Could not create signal pipe: %m");
516 pipe_configure(pipe_result[0]);
517 pipe_configure(pipe_result[1]);
518 m->sig_pipe_recv = pipe_result[0];
519 m->sig_pipe_send = pipe_result[1];
521 struct main_file *f = xmalloc_zero(sizeof(*f));
522 m->sig_pipe_file = f;
523 f->fd = m->sig_pipe_recv;
524 f->read_handler = pipe_read_handler;
529 signal_handler_pipe(int signum)
531 struct main_context *m = main_current();
533 msg(L_DEBUG | L_SIGHANDLER, "MAIN: Sigpipe: sending signal %d down the drain", signum);
535 write(m->sig_pipe_send, &signum, sizeof(signum));
539 signal_add(struct main_signal *ms)
541 struct main_context *m = main_current();
543 DBG("MAIN: Adding signal %p (sig=%d)", ms, ms->signum);
545 ASSERT(!clist_is_linked(&ms->n));
546 // Adding at the head of the list is better if we are in the middle of walking the list.
547 clist_add_head(&m->signal_list, &ms->n);
548 if (m->sig_pipe_recv < 0)
551 struct sigaction sa = {
552 .sa_handler = signal_handler_pipe,
553 .sa_flags = SA_NOCLDSTOP | SA_RESTART,
555 sigaction(ms->signum, &sa, NULL);
559 sigaddset(&ss, ms->signum);
560 THREAD_SIGMASK(SIG_UNBLOCK, &ss, NULL);
561 sigaddset(&m->want_signals, ms->signum);
565 signal_del_ctx(struct main_context *m, struct main_signal *ms)
567 // XXX: Can be called on a non-current context
568 DBG("MAIN: Deleting signal %p (sig=%d)", ms, ms->signum);
570 ASSERT(clist_is_linked(&ms->n));
571 clist_unlink(&ms->n);
574 CLIST_FOR_EACH(struct main_signal *, s, m->signal_list)
575 if (s->signum == ms->signum)
579 if (main_is_current(m))
583 sigaddset(&ss, ms->signum);
584 THREAD_SIGMASK(SIG_BLOCK, &ss, NULL);
586 sigdelset(&m->want_signals, ms->signum);
591 signal_del(struct main_signal *ms)
593 signal_del_ctx(main_current(), ms);
597 main_debug_context(struct main_context *m UNUSED)
600 msg(L_DEBUG, "### Main loop status on %lld", (long long) m->now);
601 msg(L_DEBUG, "\tActive timers:");
602 uns num_timers = count_timers(m);
603 for (uns i = 1; i <= num_timers; i++)
605 struct main_timer *tm = m->timer_table[i];
606 msg(L_DEBUG, "\t\t%p (expires %lld, data %p)", tm, (long long)(tm->expires ? tm->expires - m->now : 999999), tm->data);
608 msg(L_DEBUG, "\tActive files:");
609 CLIST_FOR_EACH(struct main_file *, fi, m->file_list)
610 msg(L_DEBUG, "\t\t%p (fd %d, rh %p, wh %p, data %p)",
611 fi, fi->fd, fi->read_handler, fi->write_handler, fi->data);
612 CLIST_FOR_EACH(struct main_file *, fi, m->file_active_list)
613 msg(L_DEBUG, "\t\t%p (fd %d, rh %p, wh %p, data %p) [pending events: %x]",
614 fi, fi->fd, fi->read_handler, fi->write_handler, fi->data, fi->events);
615 // FIXME: Can we display status of block_io requests somehow?
616 #ifdef CONFIG_UCW_EPOLL
617 CLIST_FOR_EACH(struct main_file *, fi, m->file_recalc_list)
618 msg(L_DEBUG, "\t\t%p (fd %d, rh %p, wh %p, data %p) [pending recalculation]",
619 fi, fi->fd, fi->read_handler, fi->write_handler, fi->data);
621 msg(L_DEBUG, "\tActive hooks:");
622 CLIST_FOR_EACH(struct main_hook *, ho, m->hook_done_list)
623 msg(L_DEBUG, "\t\t%p (func %p, data %p)", ho, ho->handler, ho->data);
624 CLIST_FOR_EACH(struct main_hook *, ho, m->hook_list)
625 msg(L_DEBUG, "\t\t%p (func %p, data %p)", ho, ho->handler, ho->data);
626 msg(L_DEBUG, "\tActive processes:");
627 CLIST_FOR_EACH(struct main_process *, pr, m->process_list)
628 msg(L_DEBUG, "\t\t%p (pid %d, func %p, data %p)", pr, pr->pid, pr->handler, pr->data);
629 msg(L_DEBUG, "\tActive signal catchers:");
630 CLIST_FOR_EACH(struct main_signal *, sg, m->signal_list)
632 msg(L_DEBUG, "\t\t(placeholder)");
634 msg(L_DEBUG, "\t\t%p (sig %d, func %p, data %p)", sg, sg->signum, sg->handler, sg->data);
639 process_timers(struct main_context *m)
641 struct main_timer *tm;
642 while (count_timers(m) && (tm = m->timer_table[1])->expires <= m->now)
644 DBG("MAIN: Timer %p expired at now-%lld", tm, (long long)(m->now - tm->expires));
649 static enum main_hook_return
650 process_hooks(struct main_context *m)
652 int hook_min = HOOK_RETRY;
653 int hook_max = HOOK_SHUTDOWN;
654 struct main_hook *ho;
656 while (ho = clist_remove_head(&m->hook_list))
658 clist_add_tail(&m->hook_done_list, &ho->n);
659 DBG("MAIN: Hook %p", ho);
660 int ret = ho->handler(ho);
661 hook_min = MIN(hook_min, ret);
662 hook_max = MAX(hook_max, ret);
664 clist_move(&m->hook_list, &m->hook_done_list);
665 if (hook_min == HOOK_SHUTDOWN ||
666 hook_min == HOOK_DONE && hook_max == HOOK_DONE ||
669 DBG("MAIN: Shut down by %s", m->shutdown ? "main_shutdown" : "a hook");
670 return HOOK_SHUTDOWN;
672 if (hook_max == HOOK_RETRY)
678 #ifdef CONFIG_UCW_EPOLL
681 recalc_files(struct main_context *m)
683 struct main_file *fi;
685 while (fi = clist_remove_head(&m->file_recalc_list))
687 struct epoll_event evt = {
688 .events = file_want_events(fi),
691 if (evt.events != fi->last_want_events)
693 DBG("MAIN: Changing requested events for fd %d to %x", fi->fd, evt.events);
694 fi->last_want_events = evt.events;
695 if (epoll_ctl(main_current()->epoll_fd, EPOLL_CTL_MOD, fi->fd, &evt) < 0)
696 die("epoll_ctl() failed: %m");
698 clist_add_tail(&m->file_list, &fi->n);
705 rebuild_poll_table(struct main_context *m)
707 GARY_INIT_OR_RESIZE(m->poll_table, m->file_cnt);
708 GARY_INIT_OR_RESIZE(m->poll_file_table, m->file_cnt);
709 DBG("MAIN: Rebuilding poll table: %d entries", m->file_cnt);
711 struct pollfd *p = m->poll_table;
712 struct main_file **pf = m->poll_file_table;
713 CLIST_FOR_EACH(struct main_file *, fi, m->file_list)
716 p->events = file_want_events(fi);
720 m->poll_table_obsolete = 0;
728 DBG("MAIN: Entering main_loop");
729 struct main_context *m = main_current();
731 main_get_time_ctx(m);
734 timestamp_t wake = m->now + 1000000000;
736 switch (process_hooks(m))
746 wake = MIN(wake, m->timer_table[1]->expires);
747 main_get_time_ctx(m);
748 int timeout = ((wake > m->now) ? wake - m->now : 0);
750 #ifdef CONFIG_UCW_EPOLL
752 DBG("MAIN: Epoll for %d fds and timeout %d ms", m->file_cnt, timeout);
753 int n = epoll_wait(m->epoll_fd, m->epoll_events, EPOLL_BUF_SIZE, timeout);
755 if (m->poll_table_obsolete)
756 rebuild_poll_table(m);
757 DBG("MAIN: Poll for %d fds and timeout %d ms", m->file_cnt, timeout);
758 int n = poll(m->poll_table, m->file_cnt, timeout);
761 DBG("\t-> %d events", n);
762 if (n < 0 && errno != EAGAIN && errno != EINTR)
763 die("(e)poll failed: %m");
764 timestamp_t old_now = m->now;
765 main_get_time_ctx(m);
766 m->idle_time += m->now - old_now;
771 // Relink all files with a pending event to file_active_list
772 #ifdef CONFIG_UCW_EPOLL
773 for (int i=0; i<n; i++)
775 struct epoll_event *e = &m->epoll_events[i];
776 struct main_file *fi = e->data.ptr;
777 clist_remove(&fi->n);
778 clist_add_tail(&m->file_active_list, &fi->n);
779 fi->events = e->events;
782 struct pollfd *p = m->poll_table;
783 struct main_file **pf = m->poll_file_table;
784 for (uns i=0; i < m->file_cnt; i++)
787 struct main_file *fi = pf[i];
788 clist_remove(&fi->n);
789 clist_add_tail(&m->file_active_list, &fi->n);
790 fi->events = p[i].revents;
795 * Process the buffered file events. This is pretty tricky, since
796 * user callbacks can modify the file structure or even destroy it.
797 * In such cases, we detect that the structure was relinked and stop
798 * processing its events, leaving them for the next iteration of the
801 struct main_file *fi;
802 while (fi = clist_head(&m->file_active_list))
804 if (fi->events & (POLLIN | POLLHUP | POLLERR))
806 fi->events &= ~(POLLIN | POLLHUP | POLLERR);
808 DBG("MAIN: Read event on fd %d", fi->fd);
809 while (fi->read_handler && fi->read_handler(fi));
812 if (fi->events & (POLLOUT | POLLERR))
814 fi->events &= ~(POLLOUT | POLLERR);
816 DBG("MAIN: Write event on fd %d", fi->fd);
817 while (fi->write_handler && fi->write_handler(fi));
820 clist_remove(&fi->n);
821 clist_add_tail(&m->file_list, &fi->n);