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);
78 // FIXME: Free poll table
83 main_switch_context(struct main_context *m)
85 struct ucwlib_context *c = ucwlib_thread_context();
86 struct main_context *m0 = c->main_context;
94 struct ucwlib_context *c = ucwlib_thread_context();
95 struct main_context *m = c->main_context;
103 struct main_context *m = main_switch_context(main_new());
110 struct main_context *m = main_switch_context(NULL);
117 do_main_get_time(main_current());
121 count_timers(struct main_context *m)
123 return GARY_SIZE(m->timer_table) - 1;
127 timer_add(struct main_timer *tm, timestamp_t expires)
129 struct main_context *m = main_current();
133 GARY_INIT(m->timer_table, 1);
134 m->timer_table[0] = NULL;
138 DBG("MAIN: Setting timer %p (expire at now+%lld)", tm, (long long)(expires - m->now));
140 DBG("MAIN: Clearing timer %p", tm);
141 uns num_timers = count_timers(m);
142 if (tm->expires < expires)
146 tm->expires = expires;
147 tm->index = num_timers + 1;
148 *GARY_PUSH(m->timer_table, 1) = tm;
149 HEAP_INSERT(struct main_timer *, m->timer_table, tm->index, MAIN_TIMER_LESS, MAIN_TIMER_SWAP);
153 tm->expires = expires;
154 HEAP_INCREASE(struct main_timer *, m->timer_table, num_timers, MAIN_TIMER_LESS, MAIN_TIMER_SWAP, tm->index);
157 else if (tm->expires > expires)
161 ASSERT(tm->index && tm->index <= num_timers);
162 HEAP_DELETE(struct main_timer *, m->timer_table, num_timers, MAIN_TIMER_LESS, MAIN_TIMER_SWAP, tm->index);
165 GARY_POP(m->timer_table, 1);
169 tm->expires = expires;
170 HEAP_DECREASE(struct main_timer *, m->timer_table, num_timers, MAIN_TIMER_LESS, MAIN_TIMER_SWAP, tm->index);
176 timer_del(struct main_timer *tm)
182 file_timer_expired(struct main_timer *tm)
184 struct main_file *fi = tm->data;
185 timer_del(&fi->timer);
186 if (fi->error_handler)
187 fi->error_handler(fi, MFERR_TIMEOUT);
191 file_add(struct main_file *fi)
193 struct main_context *m = main_current();
195 DBG("MAIN: Adding file %p (fd=%d)", fi, fi->fd);
197 clist_add_tail(&m->file_list, &fi->n);
198 fi->timer.handler = file_timer_expired;
201 m->poll_table_obsolete = 1;
202 if (fcntl(fi->fd, F_SETFL, O_NONBLOCK) < 0)
203 msg(L_ERROR, "Error setting fd %d to non-blocking mode: %m. Keep fingers crossed.", fi->fd);
207 file_chg(struct main_file *fi)
209 struct pollfd *p = fi->pollfd;
213 if (fi->read_handler)
214 p->events |= POLLIN | POLLHUP | POLLERR;
215 if (fi->write_handler)
216 p->events |= POLLOUT | POLLERR;
221 file_del(struct main_file *fi)
223 struct main_context *m = main_current();
225 DBG("MAIN: Deleting file %p (fd=%d)", fi, fi->fd);
227 timer_del(&fi->timer);
228 clist_remove(&fi->n);
230 m->poll_table_obsolete = 1;
231 fi->n.next = fi->n.prev = NULL;
235 file_read_handler(struct main_file *fi)
237 while (fi->rpos < fi->rlen)
239 int l = read(fi->fd, fi->rbuf + fi->rpos, fi->rlen - fi->rpos);
240 DBG("MAIN: FD %d: read %d", fi->fd, l);
243 if (errno != EINTR && errno != EAGAIN && fi->error_handler)
244 fi->error_handler(fi, MFERR_READ);
251 DBG("MAIN: FD %d done read %d of %d", fi->fd, fi->rpos, fi->rlen);
252 fi->read_handler = NULL;
259 file_write_handler(struct main_file *fi)
261 while (fi->wpos < fi->wlen)
263 int l = write(fi->fd, fi->wbuf + fi->wpos, fi->wlen - fi->wpos);
264 DBG("MAIN: FD %d: write %d", fi->fd, l);
267 if (errno != EINTR && errno != EAGAIN && fi->error_handler)
268 fi->error_handler(fi, MFERR_WRITE);
273 DBG("MAIN: FD %d done write %d", fi->fd, fi->wpos);
274 fi->write_handler = NULL;
281 file_read(struct main_file *fi, void *buf, uns len)
286 fi->read_handler = file_read_handler;
293 fi->read_handler = NULL;
295 fi->rpos = fi->rlen = 0;
301 file_write(struct main_file *fi, void *buf, uns len)
306 fi->write_handler = file_write_handler;
313 fi->write_handler = NULL;
315 fi->wpos = fi->wlen = 0;
321 file_set_timeout(struct main_file *fi, timestamp_t expires)
324 timer_add(&fi->timer, expires);
330 struct main_context *m = main_current();
332 CLIST_FOR_EACH(struct main_file *, f, m->file_list)
337 hook_add(struct main_hook *ho)
339 struct main_context *m = main_current();
341 DBG("MAIN: Adding hook %p", ho);
343 clist_add_tail(&m->hook_list, &ho->n);
347 hook_del(struct main_hook *ho)
349 DBG("MAIN: Deleting hook %p", ho);
351 clist_remove(&ho->n);
352 ho->n.next = ho->n.prev = NULL;
357 main_sigchld_handler(int x UNUSED)
359 int old_errno = errno;
360 DBG("SIGCHLD received");
363 while((result = write(sig_pipe_send, "c", 1)) == -1 && errno == EINTR);
364 if(result == -1 && errno != EAGAIN)
365 msg(L_SIGHANDLER|L_ERROR, "Could not write to self-pipe: %m");
370 dummy_read_handler(struct main_file *mp)
373 ssize_t result = read(mp->fd, buffer, 1024);
374 if(result == -1 && errno != EAGAIN)
375 msg(L_ERROR, "Could not read from selfpipe: %m");
377 return result == 1024;
381 pipe_configure(int fd)
384 if((flags = fcntl(fd, F_GETFL)) == -1 || fcntl(fd, F_SETFL, flags|O_NONBLOCK))
385 die("Could not set file descriptor %d to non-blocking: %m", fd);
386 if((flags = fcntl(fd, F_GETFD)) == -1 || fcntl(fd, F_SETFD, flags|O_CLOEXEC))
387 die("Could not set file descriptor %d to close-on-exec: %m", fd);
391 main_sigchld_handler(int x UNUSED)
393 DBG("SIGCHLD received");
398 process_add(struct main_process *mp)
400 struct main_context *m = main_current();
402 DBG("MAIN: Adding process %p (pid=%d)", mp, mp->pid);
405 clist_add_tail(&m->process_list, &mp->n);
406 if (!main_sigchld_set_up)
410 if(pipe(pipe_result) == -1)
411 die("Could not create selfpipe:%m");
412 pipe_configure(pipe_result[0]);
413 pipe_configure(pipe_result[1]);
414 sig_pipe_recv = pipe_result[0];
415 sig_pipe_send = pipe_result[1];
416 static struct main_file self_pipe;
417 self_pipe = (struct main_file) {
419 .read_handler = dummy_read_handler
421 file_add(&self_pipe);
424 bzero(&sa, sizeof(sa));
425 sa.sa_handler = main_sigchld_handler;
426 sa.sa_flags = SA_NOCLDSTOP | SA_RESTART;
427 sigaction(SIGCHLD, &sa, NULL);
428 main_sigchld_set_up = 1;
429 chld_received = 1; // The signal may have come before the handler
434 process_del(struct main_process *mp)
436 DBG("MAIN: Deleting process %p (pid=%d)", mp, mp->pid);
438 clist_remove(&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 main_debug_context(struct main_context *m UNUSED)
469 msg(L_DEBUG, "### Main loop status on %lld", (long long) m->now);
470 msg(L_DEBUG, "\tActive timers:");
471 uns num_timers = count_timers(m);
472 for (uns i = 1; i <= num_timers; i++)
474 struct main_timer *tm = m->timer_table[i];
475 msg(L_DEBUG, "\t\t%p (expires %lld, data %p)", tm, (long long)(tm->expires ? tm->expires - m->now : 999999), tm->data);
477 struct main_file *fi;
478 msg(L_DEBUG, "\tActive files:");
479 CLIST_WALK(fi, m->file_list)
480 msg(L_DEBUG, "\t\t%p (fd %d, rh %p, wh %p, eh %p, expires %lld, data %p)",
481 fi, fi->fd, fi->read_handler, fi->write_handler, fi->error_handler,
482 (long long)(fi->timer.expires ? fi->timer.expires - m->now : 999999), fi->data);
483 msg(L_DEBUG, "\tActive hooks:");
484 struct main_hook *ho;
485 CLIST_WALK(ho, m->hook_done_list)
486 msg(L_DEBUG, "\t\t%p (func %p, data %p)", ho, ho->handler, ho->data);
487 CLIST_WALK(ho, m->hook_list)
488 msg(L_DEBUG, "\t\t%p (func %p, data %p)", ho, ho->handler, ho->data);
489 msg(L_DEBUG, "\tActive processes:");
490 struct main_process *pr;
491 CLIST_WALK(pr, m->process_list)
492 msg(L_DEBUG, "\t\t%p (pid %d, data %p)", pr, pr->pid, pr->data);
497 main_rebuild_poll_table(struct main_context *m)
499 struct main_file *fi;
500 if (m->poll_table_size < m->file_cnt)
503 xfree(m->poll_table);
505 m->poll_table_size = 1;
506 while (m->poll_table_size < m->file_cnt)
507 m->poll_table_size *= 2;
508 m->poll_table = xmalloc(sizeof(struct pollfd) * m->poll_table_size);
510 struct pollfd *p = m->poll_table;
511 DBG("MAIN: Rebuilding poll table: %d of %d entries set", m->file_cnt, m->poll_table_size);
512 CLIST_WALK(fi, m->file_list)
518 m->poll_table_obsolete = 0;
524 DBG("MAIN: Entering main_loop");
525 struct main_context *m = main_current();
527 struct main_file *fi;
528 struct main_hook *ho;
529 struct main_timer *tm;
530 struct main_process *pr;
535 timestamp_t wake = m->now + 1000000000;
536 while (GARY_SIZE(m->timer_table) > 1 && (tm = m->timer_table[1])->expires <= m->now)
538 DBG("MAIN: Timer %p expired at now-%lld", tm, (long long)(m->now - tm->expires));
541 int hook_min = HOOK_RETRY;
542 int hook_max = HOOK_SHUTDOWN;
543 while (ho = clist_remove_head(&m->hook_list))
545 clist_add_tail(&m->hook_done_list, &ho->n);
546 DBG("MAIN: Hook %p", ho);
547 int ret = ho->handler(ho);
548 hook_min = MIN(hook_min, ret);
549 hook_max = MAX(hook_max, ret);
551 clist_move(&m->hook_list, &m->hook_done_list);
552 if (hook_min == HOOK_SHUTDOWN ||
553 hook_min == HOOK_DONE && hook_max == HOOK_DONE ||
556 DBG("MAIN: Shut down by %s", m->shutdown ? "main_shutdown" : "a hook");
559 if (hook_max == HOOK_RETRY)
561 if (m->poll_table_obsolete)
562 main_rebuild_poll_table(m);
563 #ifndef USE_SELF_PIPE
564 // We don't have a reliable flag without the self-pipe.
567 if (chld_received && !clist_empty(&m->process_list))
571 wake = MIN(wake, m->now + 10000);
573 while ((pid = waitpid(-1, &stat, WNOHANG)) > 0)
575 DBG("MAIN: Child %d exited with status %x", pid, stat);
576 CLIST_WALK(pr, m->process_list)
581 format_exit_status(pr->status_msg, pr->status);
582 DBG("MAIN: Calling process exit handler");
589 if (count_timers(m) && (tm = m->timer_table[1])->expires < wake)
592 int timeout = ((wake > m->now) ? wake - m->now : 0);
593 DBG("MAIN: Poll for %d fds and timeout %d ms", m->file_cnt, timeout);
594 int p = poll(m->poll_table, m->file_cnt, timeout);
595 timestamp_t old_now = m->now;
597 m->idle_time += m->now - old_now;
600 struct pollfd *p = m->poll_table;
601 CLIST_WALK(fi, m->file_list)
603 if (p->revents & (POLLIN | POLLHUP | POLLERR))
606 DBG("MAIN: Read event on fd %d", p->fd);
607 while (fi->read_handler && fi->read_handler(fi) && !m->poll_table_obsolete);
608 if (m->poll_table_obsolete) /* File entries have been inserted or deleted => better not risk continuing to nowhere */
611 if (p->revents & (POLLOUT | POLLERR))
614 DBG("MAIN: Write event on fd %d", p->fd);
615 while (fi->write_handler && fi->write_handler(fi) && !m->poll_table_obsolete);
616 if (m->poll_table_obsolete)
627 static struct main_process mp;
628 static struct main_file fin, fout;
629 static struct main_hook hook;
630 static struct main_timer tm;
634 static void dread(struct main_file *fi)
636 if (fi->rpos < fi->rlen)
638 msg(L_INFO, "Read EOF");
643 msg(L_INFO, "Read done");
644 file_read(fi, rb, sizeof(rb));
648 static void derror(struct main_file *fi, int cause)
650 msg(L_INFO, "Error: %m !!! (cause %d)", cause);
654 static void dwrite(struct main_file *fi UNUSED)
656 msg(L_INFO, "Write done");
659 static int dhook(struct main_hook *ho UNUSED)
661 msg(L_INFO, "Hook called");
665 static void dtimer(struct main_timer *tm)
667 msg(L_INFO, "Timer tick");
668 timer_add(tm, main_get_now() + 10000);
671 static void dentry(void)
673 msg(L_INFO, "*** SUBPROCESS START ***");
675 msg(L_INFO, "*** SUBPROCESS FINISH ***");
679 static void dexit(struct main_process *pr)
681 msg(L_INFO, "Subprocess %d exited with status %x", pr->pid, pr->status);
691 fin.read_done = dread;
692 fin.error_handler = derror;
694 file_read(&fin, rb, sizeof(rb));
697 fout.write_done = dwrite;
698 fout.error_handler = derror;
700 file_write(&fout, "Hello, world!\n", 14);
702 hook.handler = dhook;
706 timer_add(&tm, main_get_now() + 1000);
709 if (!process_fork(&mp))
715 msg(L_INFO, "Finished.");