2 * UCW Library -- Main Loop
4 * (c) 2004--2006 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"
28 ucw_time_t main_now_seconds;
29 timestamp_t main_idle_time;
32 #define GBUF_PREFIX(x) main_timer_table_##x
33 #define GBUF_TYPE struct main_timer *
35 static uns main_timer_cnt;
36 static main_timer_table_t main_timer_table;
37 #define MAIN_TIMER_LESS(x,y) ((x)->expires < (y)->expires)
38 #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))
40 clist main_file_list, main_hook_list, main_process_list;
41 static uns main_file_cnt;
42 static uns main_poll_table_obsolete, main_poll_table_size;
43 static struct pollfd *main_poll_table;
44 static uns main_sigchld_set_up;
45 static volatile sig_atomic_t chld_received = 0;
48 // On recent Linux systems, O_CLOEXEC flag is available and we can get around
49 // the race condition of poll().
51 static int sig_pipe_recv, sig_pipe_send;
58 gettimeofday(&tv, NULL);
59 main_now_seconds = tv.tv_sec;
60 main_now = (timestamp_t)tv.tv_sec * 1000 + tv.tv_usec / 1000;
61 // DBG("It's %lld o'clock", (long long) main_now);
67 DBG("MAIN: Initializing");
69 clist_init(&main_file_list);
70 clist_init(&main_hook_list);
71 clist_init(&main_process_list);
73 main_poll_table_obsolete = 1;
78 timer_add(struct main_timer *tm, timestamp_t expires)
81 DBG("MAIN: Setting timer %p (expire at now+%lld)", tm, (long long)(expires-main_now));
83 DBG("MAIN: Clearing timer %p", tm);
84 if (tm->expires < expires)
88 tm->expires = expires;
89 tm->index = ++main_timer_cnt;
90 main_timer_table_grow(&main_timer_table, tm->index + 1);
91 main_timer_table.ptr[tm->index] = tm;
92 HEAP_INSERT(struct main_timer *, main_timer_table.ptr, main_timer_cnt, MAIN_TIMER_LESS, MAIN_TIMER_SWAP);
96 tm->expires = expires;
97 HEAP_INCREASE(struct main_timer *, main_timer_table.ptr, main_timer_cnt, MAIN_TIMER_LESS, MAIN_TIMER_SWAP, tm->index);
100 else if (tm->expires > expires)
104 ASSERT(tm->index && tm->index <= main_timer_cnt);
105 HEAP_DELETE(struct main_timer *, main_timer_table.ptr, main_timer_cnt, MAIN_TIMER_LESS, MAIN_TIMER_SWAP, tm->index);
111 tm->expires = expires;
112 HEAP_DECREASE(struct main_timer *, main_timer_table.ptr, main_timer_cnt, MAIN_TIMER_LESS, MAIN_TIMER_SWAP, tm->index);
118 timer_del(struct main_timer *tm)
124 file_timer_expired(struct main_timer *tm)
126 struct main_file *fi = tm->data;
127 timer_del(&fi->timer);
128 if (fi->error_handler)
129 fi->error_handler(fi, MFERR_TIMEOUT);
133 file_add(struct main_file *fi)
135 DBG("MAIN: Adding file %p (fd=%d)", fi, fi->fd);
137 clist_add_tail(&main_file_list, &fi->n);
138 fi->timer.handler = file_timer_expired;
141 main_poll_table_obsolete = 1;
142 if (fcntl(fi->fd, F_SETFL, O_NONBLOCK) < 0)
143 msg(L_ERROR, "Error setting fd %d to non-blocking mode: %m. Keep fingers crossed.", fi->fd);
147 file_chg(struct main_file *fi)
149 struct pollfd *p = fi->pollfd;
153 if (fi->read_handler)
154 p->events |= POLLIN | POLLHUP | POLLERR;
155 if (fi->write_handler)
156 p->events |= POLLOUT | POLLERR;
161 file_del(struct main_file *fi)
163 DBG("MAIN: Deleting file %p (fd=%d)", fi, fi->fd);
165 timer_del(&fi->timer);
166 clist_remove(&fi->n);
168 main_poll_table_obsolete = 1;
169 fi->n.next = fi->n.prev = NULL;
173 file_read_handler(struct main_file *fi)
175 while (fi->rpos < fi->rlen)
177 int l = read(fi->fd, fi->rbuf + fi->rpos, fi->rlen - fi->rpos);
178 DBG("MAIN: FD %d: read %d", fi->fd, l);
181 if (errno != EINTR && errno != EAGAIN && fi->error_handler)
182 fi->error_handler(fi, MFERR_READ);
189 DBG("MAIN: FD %d done read %d of %d", fi->fd, fi->rpos, fi->rlen);
190 fi->read_handler = NULL;
197 file_write_handler(struct main_file *fi)
199 while (fi->wpos < fi->wlen)
201 int l = write(fi->fd, fi->wbuf + fi->wpos, fi->wlen - fi->wpos);
202 DBG("MAIN: FD %d: write %d", fi->fd, l);
205 if (errno != EINTR && errno != EAGAIN && fi->error_handler)
206 fi->error_handler(fi, MFERR_WRITE);
211 DBG("MAIN: FD %d done write %d", fi->fd, fi->wpos);
212 fi->write_handler = NULL;
219 file_read(struct main_file *fi, void *buf, uns len)
224 fi->read_handler = file_read_handler;
231 fi->read_handler = NULL;
233 fi->rpos = fi->rlen = 0;
239 file_write(struct main_file *fi, void *buf, uns len)
244 fi->write_handler = file_write_handler;
251 fi->write_handler = NULL;
253 fi->wpos = fi->wlen = 0;
259 file_set_timeout(struct main_file *fi, timestamp_t expires)
262 timer_add(&fi->timer, expires);
268 CLIST_FOR_EACH(struct main_file *, f, main_file_list)
273 hook_add(struct main_hook *ho)
275 DBG("MAIN: Adding hook %p", ho);
277 clist_add_tail(&main_hook_list, &ho->n);
281 hook_del(struct main_hook *ho)
283 DBG("MAIN: Deleting hook %p", ho);
285 clist_remove(&ho->n);
286 ho->n.next = ho->n.prev = NULL;
291 main_sigchld_handler(int x UNUSED)
293 int old_errno = errno;
294 DBG("SIGCHLD received");
297 while((result = write(sig_pipe_send, "c", 1)) == -1 && errno == EINTR);
298 if(result == -1 && errno != EAGAIN)
299 msg(L_SIGHANDLER|L_ERROR, "Could not write to self-pipe: %m");
304 dummy_read_handler(struct main_file *mp)
307 ssize_t result = read(mp->fd, buffer, 1024);
308 if(result == -1 && errno != EAGAIN)
309 msg(L_ERROR, "Could not read from selfpipe: %m");
311 return result == 1024;
315 pipe_configure(int fd)
318 if((flags = fcntl(fd, F_GETFL)) == -1 || fcntl(fd, F_SETFL, flags|O_NONBLOCK))
319 die("Could not set file descriptor %d to non-blocking: %m", fd);
320 if((flags = fcntl(fd, F_GETFD)) == -1 || fcntl(fd, F_SETFD, flags|O_CLOEXEC))
321 die("Could not set file descriptor %d to close-on-exec: %m", fd);
325 main_sigchld_handler(int x UNUSED)
327 DBG("SIGCHLD received");
332 process_add(struct main_process *mp)
334 DBG("MAIN: Adding process %p (pid=%d)", mp, mp->pid);
337 clist_add_tail(&main_process_list, &mp->n);
338 if (!main_sigchld_set_up)
342 if(pipe(pipe_result) == -1)
343 die("Could not create selfpipe:%m");
344 pipe_configure(pipe_result[0]);
345 pipe_configure(pipe_result[1]);
346 sig_pipe_recv = pipe_result[0];
347 sig_pipe_send = pipe_result[1];
348 static struct main_file self_pipe;
349 self_pipe = (struct main_file) {
351 .read_handler = dummy_read_handler
353 file_add(&self_pipe);
356 bzero(&sa, sizeof(sa));
357 sa.sa_handler = main_sigchld_handler;
358 sa.sa_flags = SA_NOCLDSTOP | SA_RESTART;
359 sigaction(SIGCHLD, &sa, NULL);
360 main_sigchld_set_up = 1;
361 chld_received = 1; // The signal may have come before the handler
366 process_del(struct main_process *mp)
368 DBG("MAIN: Deleting process %p (pid=%d)", mp, mp->pid);
370 clist_remove(&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);
401 msg(L_DEBUG, "### Main loop status on %lld", (long long)main_now);
402 msg(L_DEBUG, "\tActive timers:");
403 for (uns i = 1; i <= main_timer_cnt; i++)
405 struct main_timer *tm = main_timer_table.ptr[i];
406 msg(L_DEBUG, "\t\t%p (expires %lld, data %p)", tm, (long long)(tm->expires ? tm->expires-main_now : 999999), tm->data);
408 struct main_file *fi;
409 msg(L_DEBUG, "\tActive files:");
410 CLIST_WALK(fi, main_file_list)
411 msg(L_DEBUG, "\t\t%p (fd %d, rh %p, wh %p, eh %p, expires %lld, data %p)",
412 fi, fi->fd, fi->read_handler, fi->write_handler, fi->error_handler,
413 (long long)(fi->timer.expires ? fi->timer.expires-main_now : 999999), fi->data);
414 msg(L_DEBUG, "\tActive hooks:");
415 struct main_hook *ho;
416 CLIST_WALK(ho, main_hook_list)
417 msg(L_DEBUG, "\t\t%p (func %p, data %p)", ho, ho->handler, ho->data);
418 msg(L_DEBUG, "\tActive processes:");
419 struct main_process *pr;
420 CLIST_WALK(pr, main_process_list)
421 msg(L_DEBUG, "\t\t%p (pid %d, data %p)", pr, pr->pid, pr->data);
426 main_rebuild_poll_table(void)
428 struct main_file *fi;
429 if (main_poll_table_size < main_file_cnt)
432 xfree(main_poll_table);
434 main_poll_table_size = 1;
435 while (main_poll_table_size < main_file_cnt)
436 main_poll_table_size *= 2;
437 main_poll_table = xmalloc(sizeof(struct pollfd) * main_poll_table_size);
439 struct pollfd *p = main_poll_table;
440 DBG("MAIN: Rebuilding poll table: %d of %d entries set", main_file_cnt, main_poll_table_size);
441 CLIST_WALK(fi, main_file_list)
447 main_poll_table_obsolete = 0;
453 DBG("MAIN: Entering main_loop");
454 ASSERT(main_hook_list.head.next);
456 struct main_file *fi;
457 struct main_hook *ho;
458 struct main_timer *tm;
459 struct main_process *pr;
464 timestamp_t wake = main_now + 1000000000;
465 while (main_timer_cnt && (tm = main_timer_table.ptr[1])->expires <= main_now)
467 DBG("MAIN: Timer %p expired at now-%lld", tm, (long long)(main_now - tm->expires));
470 int hook_min = HOOK_RETRY;
471 int hook_max = HOOK_SHUTDOWN;
473 clist_init(&hook_done);
474 while (ho = clist_remove_head(&main_hook_list))
476 clist_add_tail(&hook_done, &ho->n);
477 DBG("MAIN: Hook %p", ho);
478 int ret = ho->handler(ho);
479 hook_min = MIN(hook_min, ret);
480 hook_max = MAX(hook_max, ret);
482 clist_move(&main_hook_list, &hook_done);
483 if (hook_min == HOOK_SHUTDOWN ||
484 hook_min == HOOK_DONE && hook_max == HOOK_DONE ||
487 DBG("MAIN: Shut down by %s", main_shutdown ? "main_shutdown" : "a hook");
490 if (hook_max == HOOK_RETRY)
492 if (main_poll_table_obsolete)
493 main_rebuild_poll_table();
494 #ifndef USE_SELF_PIPE
495 // We don't have a reliable flag without the self-pipe.
498 if (chld_received && !clist_empty(&main_process_list))
502 wake = MIN(wake, main_now + 10000);
504 while ((pid = waitpid(-1, &stat, WNOHANG)) > 0)
506 DBG("MAIN: Child %d exited with status %x", pid, stat);
507 CLIST_WALK(pr, main_process_list)
512 format_exit_status(pr->status_msg, pr->status);
513 DBG("MAIN: Calling process exit handler");
520 if (main_timer_cnt && (tm = main_timer_table.ptr[1])->expires < wake)
523 int timeout = ((wake > main_now) ? wake - main_now : 0);
524 DBG("MAIN: Poll for %d fds and timeout %d ms", main_file_cnt, timeout);
525 int p = poll(main_poll_table, main_file_cnt, timeout);
526 timestamp_t old_now = main_now;
528 main_idle_time += main_now - old_now;
531 struct pollfd *p = main_poll_table;
532 CLIST_WALK(fi, main_file_list)
534 if (p->revents & (POLLIN | POLLHUP | POLLERR))
537 DBG("MAIN: Read event on fd %d", p->fd);
538 while (fi->read_handler && fi->read_handler(fi) && !main_poll_table_obsolete);
539 if (main_poll_table_obsolete) /* File entries have been inserted or deleted => better not risk continuing to nowhere */
542 if (p->revents & (POLLOUT | POLLERR))
545 DBG("MAIN: Write event on fd %d", p->fd);
546 while (fi->write_handler && fi->write_handler(fi) && !main_poll_table_obsolete);
547 if (main_poll_table_obsolete)
558 static struct main_process mp;
559 static struct main_file fin, fout;
560 static struct main_hook hook;
561 static struct main_timer tm;
565 static void dread(struct main_file *fi)
567 if (fi->rpos < fi->rlen)
569 msg(L_INFO, "Read EOF");
574 msg(L_INFO, "Read done");
575 file_read(fi, rb, sizeof(rb));
579 static void derror(struct main_file *fi, int cause)
581 msg(L_INFO, "Error: %m !!! (cause %d)", cause);
585 static void dwrite(struct main_file *fi UNUSED)
587 msg(L_INFO, "Write done");
590 static int dhook(struct main_hook *ho UNUSED)
592 msg(L_INFO, "Hook called");
596 static void dtimer(struct main_timer *tm)
598 msg(L_INFO, "Timer tick");
599 timer_add(tm, main_now + 10000);
602 static void dentry(void)
604 msg(L_INFO, "*** SUBPROCESS START ***");
606 msg(L_INFO, "*** SUBPROCESS FINISH ***");
610 static void dexit(struct main_process *pr)
612 msg(L_INFO, "Subprocess %d exited with status %x", pr->pid, pr->status);
622 fin.read_done = dread;
623 fin.error_handler = derror;
625 file_read(&fin, rb, sizeof(rb));
628 fout.write_done = dwrite;
629 fout.error_handler = derror;
631 file_write(&fout, "Hello, world!\n", 14);
633 hook.handler = dhook;
637 timer_add(&tm, main_now + 1000);
640 if (!process_fork(&mp))
646 msg(L_INFO, "Finished.");