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 #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
47 do_main_get_time(struct main_context *m)
50 gettimeofday(&tv, NULL);
51 m->now_seconds = tv.tv_sec;
52 m->now = (timestamp_t)tv.tv_sec * 1000 + tv.tv_usec / 1000;
58 struct main_context *m = xmalloc_zero(sizeof(*m));
60 DBG("MAIN: New context");
61 clist_init(&m->file_list);
62 clist_init(&m->file_active_list);
63 clist_init(&m->hook_list);
64 clist_init(&m->hook_done_list);
65 clist_init(&m->process_list);
66 clist_init(&m->signal_list);
67 #ifdef CONFIG_UCW_EPOLL
68 m->epoll_fd = epoll_create(64);
70 die("epoll_create() failed: %m");
71 m->epoll_events = xmalloc(EPOLL_BUF_SIZE * sizeof(struct epoll_event *));
73 m->poll_table_obsolete = 1;
76 sigemptyset(&m->want_signals);
77 m->sig_pipe_recv = m->sig_pipe_send = -1;
83 main_delete(struct main_context *m)
85 if (m->sigchld_handler)
86 signal_del(m->sigchld_handler);
88 file_del(m->sig_pipe_file);
89 if (m->sig_pipe_recv >= 0)
91 close(m->sig_pipe_recv);
92 close(m->sig_pipe_send);
94 ASSERT(clist_empty(&m->file_list));
95 ASSERT(clist_empty(&m->file_active_list));
96 ASSERT(clist_empty(&m->hook_list));
97 ASSERT(clist_empty(&m->hook_done_list));
98 ASSERT(clist_empty(&m->process_list));
99 ASSERT(clist_empty(&m->signal_list));
100 GARY_FREE(m->timer_table);
101 #ifdef CONFIG_UCW_EPOLL
102 xfree(m->epoll_events);
105 GARY_FREE(m->poll_table);
106 GARY_FREE(m->poll_file_table);
109 // FIXME: Some mechanism for cleaning up after fork()
112 struct main_context *
113 main_switch_context(struct main_context *m)
115 struct ucwlib_context *c = ucwlib_thread_context();
116 struct main_context *m0 = c->main_context;
119 * Not only we need to switch the signal sets of the two contexts,
120 * but it is also necessary to avoid invoking a signal handler
121 * in the middle of changing c->main_context.
123 if (m0 && !clist_empty(&m0->signal_list))
124 THREAD_SIGMASK(SIG_BLOCK, &m0->want_signals, NULL);
126 if (m && !clist_empty(&m->signal_list))
127 THREAD_SIGMASK(SIG_UNBLOCK, &m->want_signals, NULL);
132 struct main_context *
135 struct ucwlib_context *c = ucwlib_thread_context();
136 struct main_context *m = c->main_context;
144 struct main_context *m = main_switch_context(main_new());
151 struct main_context *m = main_switch_context(NULL);
158 do_main_get_time(main_current());
162 count_timers(struct main_context *m)
164 return GARY_SIZE(m->timer_table) - 1;
168 timer_add(struct main_timer *tm, timestamp_t expires)
170 struct main_context *m = main_current();
174 GARY_INIT(m->timer_table, 1);
175 m->timer_table[0] = NULL;
179 DBG("MAIN: Setting timer %p (expire at now+%lld)", tm, (long long)(expires - m->now));
181 DBG("MAIN: Clearing timer %p", tm);
182 uns num_timers = count_timers(m);
183 if (tm->expires < expires)
187 tm->expires = expires;
188 tm->index = num_timers + 1;
189 *GARY_PUSH(m->timer_table, 1) = tm;
190 HEAP_INSERT(struct main_timer *, m->timer_table, tm->index, MAIN_TIMER_LESS, MAIN_TIMER_SWAP);
194 tm->expires = expires;
195 HEAP_INCREASE(struct main_timer *, m->timer_table, num_timers, MAIN_TIMER_LESS, MAIN_TIMER_SWAP, tm->index);
198 else if (tm->expires > expires)
202 ASSERT(tm->index && tm->index <= num_timers);
203 HEAP_DELETE(struct main_timer *, m->timer_table, num_timers, MAIN_TIMER_LESS, MAIN_TIMER_SWAP, tm->index);
206 GARY_POP(m->timer_table, 1);
210 tm->expires = expires;
211 HEAP_DECREASE(struct main_timer *, m->timer_table, num_timers, MAIN_TIMER_LESS, MAIN_TIMER_SWAP, tm->index);
217 timer_add_rel(struct main_timer *tm, timestamp_t expires_delta)
219 struct main_context *m = main_current();
220 return timer_add(tm, m->now + expires_delta);
224 timer_del(struct main_timer *tm)
230 file_want_events(struct main_file *fi)
233 if (fi->read_handler)
234 events |= POLLIN | POLLHUP | POLLERR;
235 if (fi->write_handler)
236 events |= POLLOUT | POLLERR;
241 file_add(struct main_file *fi)
243 struct main_context *m = main_current();
245 DBG("MAIN: Adding file %p (fd=%d)", fi, fi->fd);
246 ASSERT(!clist_is_linked(&fi->n));
247 clist_add_tail(&m->file_list, &fi->n);
249 #ifdef CONFIG_UCW_EPOLL
250 struct epoll_event evt = {
251 .events = file_want_events(fi),
254 if (epoll_ctl(m->epoll_fd, EPOLL_CTL_ADD, fi->fd, &evt) < 0)
255 die("epoll_ctl() failed: %m");
257 m->poll_table_obsolete = 1;
259 if (fcntl(fi->fd, F_SETFL, O_NONBLOCK) < 0)
260 msg(L_ERROR, "Error setting fd %d to non-blocking mode: %m. Keep fingers crossed.", fi->fd);
264 file_chg(struct main_file *fi)
266 #ifdef CONFIG_UCW_EPOLL
267 struct epoll_event evt = {
268 .events = file_want_events(fi),
271 if (epoll_ctl(main_current()->epoll_fd, EPOLL_CTL_MOD, fi->fd, &evt) < 0)
272 die("epoll_ctl() failed: %m");
274 struct pollfd *p = fi->pollfd;
276 p->events = file_want_events(fi);
281 file_del(struct main_file *fi)
283 struct main_context *m = main_current();
285 DBG("MAIN: Deleting file %p (fd=%d)", fi, fi->fd);
286 ASSERT(clist_is_linked(&fi->n));
287 clist_unlink(&fi->n);
289 #ifdef CONFIG_UCW_EPOLL
290 if (epoll_ctl(m->epoll_fd, EPOLL_CTL_DEL, fi->fd, NULL) < 0)
291 die("epoll_ctl() failed: %m");
293 m->poll_table_obsolete = 1;
300 struct main_context *m = main_current();
302 CLIST_FOR_EACH(struct main_file *, f, m->file_list)
307 hook_add(struct main_hook *ho)
309 struct main_context *m = main_current();
311 DBG("MAIN: Adding hook %p", ho);
312 ASSERT(!clist_is_linked(&ho->n));
313 clist_add_tail(&m->hook_list, &ho->n);
317 hook_del(struct main_hook *ho)
319 DBG("MAIN: Deleting hook %p", ho);
320 ASSERT(clist_is_linked(&ho->n));
321 clist_unlink(&ho->n);
325 sigchld_received(struct main_signal *sg UNUSED)
327 struct main_context *m = main_current();
331 while ((pid = waitpid(-1, &stat, WNOHANG)) > 0)
333 DBG("MAIN: Child %d exited with status %x", pid, stat);
334 CLIST_FOR_EACH(struct main_process *, pr, m->process_list)
339 format_exit_status(pr->status_msg, pr->status);
340 DBG("MAIN: Calling process exit handler");
348 process_add(struct main_process *mp)
350 struct main_context *m = main_current();
352 DBG("MAIN: Adding process %p (pid=%d)", mp, mp->pid);
353 ASSERT(!clist_is_linked(&mp->n));
355 clist_add_tail(&m->process_list, &mp->n);
356 if (!m->sigchld_handler)
358 struct main_signal *sg = xmalloc_zero(sizeof(*sg));
359 m->sigchld_handler = sg;
360 sg->signum = SIGCHLD;
361 sg->handler = sigchld_received;
367 process_del(struct main_process *mp)
369 DBG("MAIN: Deleting process %p (pid=%d)", mp, mp->pid);
370 ASSERT(clist_is_linked(&mp->n));
371 clist_unlink(&mp->n);
375 process_fork(struct main_process *mp)
380 DBG("MAIN: Fork failed");
382 format_exit_status(mp->status_msg, -1);
390 DBG("MAIN: Forked process %d", (int) pid);
398 pipe_read_handler(struct main_file *mf UNUSED)
400 struct main_context *m = main_current();
402 int n = read(m->sig_pipe_recv, &signum, sizeof(signum));
407 msg(L_ERROR, "Error reading signal pipe: %m");
410 ASSERT(n == sizeof(signum));
412 DBG("MAIN: Sigpipe: received signal %d", signum);
413 struct main_signal iter = { .signum = -1 };
414 struct main_signal *sg = clist_head(&m->signal_list);
417 if (sg->signum == signum)
419 DBG("MAIN: Sigpipe: invoking handler %p", sg);
420 clist_insert_after(&iter.n, &sg->n);
422 sg = clist_next(&m->signal_list, &iter.n);
423 clist_remove(&iter.n);
426 sg = clist_next(&m->signal_list, &sg->n);
433 pipe_configure(int fd)
436 if ((flags = fcntl(fd, F_GETFL)) < 0 || fcntl(fd, F_SETFL, flags|O_NONBLOCK) < 0)
437 die("Could not set file descriptor %d to non-blocking: %m", fd);
441 pipe_setup(struct main_context *m)
443 DBG("MAIN: Sigpipe: Setting up the pipe");
446 if (pipe(pipe_result) == -1)
447 die("Could not create signal pipe: %m");
448 pipe_configure(pipe_result[0]);
449 pipe_configure(pipe_result[1]);
450 m->sig_pipe_recv = pipe_result[0];
451 m->sig_pipe_send = pipe_result[1];
453 struct main_file *f = xmalloc_zero(sizeof(*f));
454 m->sig_pipe_file = f;
455 f->fd = m->sig_pipe_recv;
456 f->read_handler = pipe_read_handler;
461 signal_handler_pipe(int signum)
463 struct main_context *m = main_current();
465 msg(L_DEBUG | L_SIGHANDLER, "MAIN: Sigpipe: sending signal %d down the drain", signum);
467 write(m->sig_pipe_send, &signum, sizeof(signum));
471 signal_add(struct main_signal *ms)
473 struct main_context *m = main_current();
475 DBG("MAIN: Adding signal %p (sig=%d)", ms, ms->signum);
477 ASSERT(!clist_is_linked(&ms->n));
478 // Adding at the head of the list is better if we are in the middle of walking the list.
479 clist_add_head(&m->signal_list, &ms->n);
480 if (m->sig_pipe_recv < 0)
483 struct sigaction sa = {
484 .sa_handler = signal_handler_pipe,
485 .sa_flags = SA_NOCLDSTOP | SA_RESTART,
487 sigaction(ms->signum, &sa, NULL);
491 sigaddset(&ss, ms->signum);
492 THREAD_SIGMASK(SIG_UNBLOCK, &ss, NULL);
493 sigaddset(&m->want_signals, ms->signum);
497 signal_del(struct main_signal *ms)
499 struct main_context *m = main_current();
501 DBG("MAIN: Deleting signal %p (sig=%d)", ms, ms->signum);
503 ASSERT(clist_is_linked(&ms->n));
504 clist_unlink(&ms->n);
507 CLIST_FOR_EACH(struct main_signal *, s, m->signal_list)
508 if (s->signum == ms->signum)
514 sigaddset(&ss, ms->signum);
515 THREAD_SIGMASK(SIG_BLOCK, &ss, NULL);
516 sigdelset(&m->want_signals, ms->signum);
521 main_debug_context(struct main_context *m UNUSED)
524 msg(L_DEBUG, "### Main loop status on %lld", (long long) m->now);
525 msg(L_DEBUG, "\tActive timers:");
526 uns num_timers = count_timers(m);
527 for (uns i = 1; i <= num_timers; i++)
529 struct main_timer *tm = m->timer_table[i];
530 msg(L_DEBUG, "\t\t%p (expires %lld, data %p)", tm, (long long)(tm->expires ? tm->expires - m->now : 999999), tm->data);
532 msg(L_DEBUG, "\tActive files:");
533 CLIST_FOR_EACH(struct main_file *, fi, m->file_list)
534 msg(L_DEBUG, "\t\t%p (fd %d, rh %p, wh %p, data %p)",
535 fi, fi->fd, fi->read_handler, fi->write_handler, fi->data);
536 CLIST_FOR_EACH(struct main_file *, fi, m->file_list)
537 msg(L_DEBUG, "\t\t%p (fd %d, rh %p, wh %p, data %p) [pending events: %x]",
538 fi, fi->fd, fi->read_handler, fi->write_handler, fi->data, fi->events);
539 // FIXME: Can we display status of block_io requests somehow?
540 msg(L_DEBUG, "\tActive hooks:");
541 CLIST_FOR_EACH(struct main_hook *, ho, m->hook_done_list)
542 msg(L_DEBUG, "\t\t%p (func %p, data %p)", ho, ho->handler, ho->data);
543 CLIST_FOR_EACH(struct main_hook *, ho, m->hook_list)
544 msg(L_DEBUG, "\t\t%p (func %p, data %p)", ho, ho->handler, ho->data);
545 msg(L_DEBUG, "\tActive processes:");
546 CLIST_FOR_EACH(struct main_process *, pr, m->process_list)
547 msg(L_DEBUG, "\t\t%p (pid %d, func %p, data %p)", pr, pr->pid, pr->handler, pr->data);
548 msg(L_DEBUG, "\tActive signal catchers:");
549 CLIST_FOR_EACH(struct main_signal *, sg, m->signal_list)
551 msg(L_DEBUG, "\t\t(placeholder)");
553 msg(L_DEBUG, "\t\t%p (sig %d, func %p, data %p)", sg, sg->signum, sg->handler, sg->data);
558 process_timers(struct main_context *m)
560 struct main_timer *tm;
561 while (GARY_SIZE(m->timer_table) > 1 && (tm = m->timer_table[1])->expires <= m->now)
563 DBG("MAIN: Timer %p expired at now-%lld", tm, (long long)(m->now - tm->expires));
568 static enum main_hook_return
569 process_hooks(struct main_context *m)
571 int hook_min = HOOK_RETRY;
572 int hook_max = HOOK_SHUTDOWN;
573 struct main_hook *ho;
575 while (ho = clist_remove_head(&m->hook_list))
577 clist_add_tail(&m->hook_done_list, &ho->n);
578 DBG("MAIN: Hook %p", ho);
579 int ret = ho->handler(ho);
580 hook_min = MIN(hook_min, ret);
581 hook_max = MAX(hook_max, ret);
583 clist_move(&m->hook_list, &m->hook_done_list);
584 if (hook_min == HOOK_SHUTDOWN ||
585 hook_min == HOOK_DONE && hook_max == HOOK_DONE ||
588 DBG("MAIN: Shut down by %s", m->shutdown ? "main_shutdown" : "a hook");
589 return HOOK_SHUTDOWN;
591 if (hook_max == HOOK_RETRY)
597 #ifndef CONFIG_UCW_EPOLL
600 main_rebuild_poll_table(struct main_context *m)
602 GARY_INIT_OR_RESIZE(m->poll_table, m->file_cnt);
603 GARY_INIT_OR_RESIZE(m->poll_file_table, m->file_cnt);
604 DBG("MAIN: Rebuilding poll table: %d entries", m->file_cnt);
606 struct pollfd *p = m->poll_table;
607 struct main_file **pf = m->poll_file_table;
608 CLIST_FOR_EACH(struct main_file *, fi, m->file_list)
615 m->poll_table_obsolete = 0;
623 DBG("MAIN: Entering main_loop");
624 struct main_context *m = main_current();
629 timestamp_t wake = m->now + 1000000000;
631 switch (process_hooks(m))
641 wake = MIN(wake, m->timer_table[1]->expires);
643 int timeout = ((wake > m->now) ? wake - m->now : 0);
645 #ifdef CONFIG_UCW_EPOLL
646 DBG("MAIN: Epoll for %d fds and timeout %d ms", m->file_cnt, timeout);
647 int n = epoll_wait(m->epoll_fd, m->epoll_events, EPOLL_BUF_SIZE, timeout);
649 if (m->poll_table_obsolete)
650 main_rebuild_poll_table(m);
651 DBG("MAIN: Poll for %d fds and timeout %d ms", m->file_cnt, timeout);
652 int n = poll(m->poll_table, m->file_cnt, timeout);
655 DBG("\t-> %d events", n);
656 if (n < 0 && errno != EAGAIN && errno != EINTR)
657 die("(e)poll failed: %m");
658 timestamp_t old_now = m->now;
660 m->idle_time += m->now - old_now;
665 // Relink all files with a pending event to file_active_list
666 #ifdef CONFIG_UCW_EPOLL
667 for (int i=0; i<n; i++)
669 struct epoll_event *e = &m->epoll_events[i];
670 struct main_file *fi = e->data.ptr;
671 clist_remove(&fi->n);
672 clist_add_tail(&m->file_active_list, &fi->n);
673 fi->events = e->events;
676 struct pollfd *p = m->poll_table;
677 struct main_file **pf = m->poll_file_table;
678 for (uns i=0; i < m->file_cnt; i++)
681 struct main_file *fi = pf[i];
682 clist_remove(&fi->n);
683 clist_add_tail(&m->file_active_list, &fi->n);
684 fi->events = p[i].revents;
688 // Process the buffered file events
689 struct main_file *fi;
690 while (fi = clist_remove_head(&m->file_active_list))
692 clist_add_tail(&m->file_list, &fi->n);
693 if (fi->events & (POLLIN | POLLHUP | POLLERR))
696 DBG("MAIN: Read event on fd %d", fi->fd);
697 while (fi->read_handler && fi->read_handler(fi));
699 if (fi->events & (POLLOUT | POLLERR))
702 DBG("MAIN: Write event on fd %d", fi->fd);
703 while (fi->write_handler && fi->write_handler(fi));
711 static struct main_process mp;
712 static struct main_block_io fin, fout;
713 static struct main_hook hook;
714 static struct main_timer tm;
715 static struct main_signal sg;
719 static void dread(struct main_block_io *bio)
721 if (bio->rpos < bio->rlen)
723 msg(L_INFO, "Read EOF");
728 msg(L_INFO, "Read done");
729 block_io_read(bio, rb, sizeof(rb));
733 static void derror(struct main_block_io *bio, int cause)
735 msg(L_INFO, "Error: %m !!! (cause %d)", cause);
739 static void dwrite(struct main_block_io *bio UNUSED)
741 msg(L_INFO, "Write done");
744 static int dhook(struct main_hook *ho UNUSED)
746 msg(L_INFO, "Hook called");
750 static void dtimer(struct main_timer *tm)
752 msg(L_INFO, "Timer tick");
753 timer_add_rel(tm, 11000);
754 timer_add_rel(tm, 10000);
757 static void dentry(void)
759 msg(L_INFO, "*** SUBPROCESS START ***");
761 msg(L_INFO, "*** SUBPROCESS FINISH ***");
765 static void dexit(struct main_process *pr)
767 msg(L_INFO, "Subprocess %d exited with status %x", pr->pid, pr->status);
770 static void dsignal(struct main_signal *sg UNUSED)
772 msg(L_INFO, "SIGINT received (use Ctrl-\\ to really quit)");
781 fin.read_done = dread;
782 fin.error_handler = derror;
783 block_io_add(&fin, 0);
784 block_io_read(&fin, rb, sizeof(rb));
786 fout.write_done = dwrite;
787 fout.error_handler = derror;
788 block_io_add(&fout, 1);
789 block_io_write(&fout, "Hello, world!\n", 14);
791 hook.handler = dhook;
795 timer_add_rel(&tm, 1000);
798 sg.handler = dsignal;
802 if (!process_fork(&mp))
808 msg(L_INFO, "Finished.");