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);
86 ASSERT(tm->index && tm->index <= main_timer_cnt);
87 HEAP_DELETE(struct main_timer *, main_timer_table.ptr, main_timer_cnt, MAIN_TIMER_LESS, MAIN_TIMER_SWAP, tm->index);
90 tm->expires = expires;
93 tm->index = ++main_timer_cnt;
94 main_timer_table_grow(&main_timer_table, tm->index + 1);
95 main_timer_table.ptr[tm->index] = tm;
96 HEAP_INSERT(struct main_timer *, main_timer_table.ptr, main_timer_cnt, MAIN_TIMER_LESS, MAIN_TIMER_SWAP);
101 timer_del(struct main_timer *tm)
107 file_timer_expired(struct main_timer *tm)
109 struct main_file *fi = tm->data;
110 timer_del(&fi->timer);
111 if (fi->error_handler)
112 fi->error_handler(fi, MFERR_TIMEOUT);
116 file_add(struct main_file *fi)
118 DBG("MAIN: Adding file %p (fd=%d)", fi, fi->fd);
120 clist_add_tail(&main_file_list, &fi->n);
121 fi->timer.handler = file_timer_expired;
124 main_poll_table_obsolete = 1;
125 if (fcntl(fi->fd, F_SETFL, O_NONBLOCK) < 0)
126 msg(L_ERROR, "Error setting fd %d to non-blocking mode: %m. Keep fingers crossed.", fi->fd);
130 file_chg(struct main_file *fi)
132 struct pollfd *p = fi->pollfd;
136 if (fi->read_handler)
137 p->events |= POLLIN | POLLHUP | POLLERR;
138 if (fi->write_handler)
139 p->events |= POLLOUT | POLLERR;
144 file_del(struct main_file *fi)
146 DBG("MAIN: Deleting file %p (fd=%d)", fi, fi->fd);
148 timer_del(&fi->timer);
149 clist_remove(&fi->n);
151 main_poll_table_obsolete = 1;
152 fi->n.next = fi->n.prev = NULL;
156 file_read_handler(struct main_file *fi)
158 while (fi->rpos < fi->rlen)
160 int l = read(fi->fd, fi->rbuf + fi->rpos, fi->rlen - fi->rpos);
161 DBG("MAIN: FD %d: read %d", fi->fd, l);
164 if (errno != EINTR && errno != EAGAIN && fi->error_handler)
165 fi->error_handler(fi, MFERR_READ);
172 DBG("MAIN: FD %d done read %d of %d", fi->fd, fi->rpos, fi->rlen);
173 fi->read_handler = NULL;
180 file_write_handler(struct main_file *fi)
182 while (fi->wpos < fi->wlen)
184 int l = write(fi->fd, fi->wbuf + fi->wpos, fi->wlen - fi->wpos);
185 DBG("MAIN: FD %d: write %d", fi->fd, l);
188 if (errno != EINTR && errno != EAGAIN && fi->error_handler)
189 fi->error_handler(fi, MFERR_WRITE);
194 DBG("MAIN: FD %d done write %d", fi->fd, fi->wpos);
195 fi->write_handler = NULL;
202 file_read(struct main_file *fi, void *buf, uns len)
207 fi->read_handler = file_read_handler;
214 fi->read_handler = NULL;
216 fi->rpos = fi->rlen = 0;
222 file_write(struct main_file *fi, void *buf, uns len)
227 fi->write_handler = file_write_handler;
234 fi->write_handler = NULL;
236 fi->wpos = fi->wlen = 0;
242 file_set_timeout(struct main_file *fi, timestamp_t expires)
245 timer_add(&fi->timer, expires);
251 CLIST_FOR_EACH(struct main_file *, f, main_file_list)
256 hook_add(struct main_hook *ho)
258 DBG("MAIN: Adding hook %p", ho);
260 clist_add_tail(&main_hook_list, &ho->n);
264 hook_del(struct main_hook *ho)
266 DBG("MAIN: Deleting hook %p", ho);
268 clist_remove(&ho->n);
269 ho->n.next = ho->n.prev = NULL;
274 main_sigchld_handler(int x UNUSED)
276 int old_errno = errno;
277 DBG("SIGCHLD received");
280 while((result = write(sig_pipe_send, "c", 1)) == -1 && errno == EINTR);
281 if(result == -1 && errno != EAGAIN)
282 msg(L_SIGHANDLER|L_ERROR, "Could not write to self-pipe: %m");
287 dummy_read_handler(struct main_file *mp)
290 ssize_t result = read(mp->fd, buffer, 1024);
291 if(result == -1 && errno != EAGAIN)
292 msg(L_ERROR, "Could not read from selfpipe: %m");
294 return result == 1024;
298 pipe_configure(int fd)
301 if((flags = fcntl(fd, F_GETFL)) == -1 || fcntl(fd, F_SETFL, flags|O_NONBLOCK))
302 die("Could not set file descriptor %d to non-blocking: %m", fd);
303 if((flags = fcntl(fd, F_GETFD)) == -1 || fcntl(fd, F_SETFD, flags|O_CLOEXEC))
304 die("Could not set file descriptor %d to close-on-exec: %m", fd);
308 main_sigchld_handler(int x UNUSED)
310 DBG("SIGCHLD received");
315 process_add(struct main_process *mp)
317 DBG("MAIN: Adding process %p (pid=%d)", mp, mp->pid);
320 clist_add_tail(&main_process_list, &mp->n);
321 if (!main_sigchld_set_up)
325 if(pipe(pipe_result) == -1)
326 die("Could not create selfpipe:%m");
327 pipe_configure(pipe_result[0]);
328 pipe_configure(pipe_result[1]);
329 sig_pipe_recv = pipe_result[0];
330 sig_pipe_send = pipe_result[1];
331 static struct main_file self_pipe;
332 self_pipe = (struct main_file) {
334 .read_handler = dummy_read_handler
336 file_add(&self_pipe);
339 bzero(&sa, sizeof(sa));
340 sa.sa_handler = main_sigchld_handler;
341 sa.sa_flags = SA_NOCLDSTOP | SA_RESTART;
342 sigaction(SIGCHLD, &sa, NULL);
343 main_sigchld_set_up = 1;
344 chld_received = 1; // The signal may have come before the handler
349 process_del(struct main_process *mp)
351 DBG("MAIN: Deleting process %p (pid=%d)", mp, mp->pid);
353 clist_remove(&mp->n);
358 process_fork(struct main_process *mp)
363 DBG("MAIN: Fork failed");
365 format_exit_status(mp->status_msg, -1);
373 DBG("MAIN: Forked process %d", (int) pid);
384 msg(L_DEBUG, "### Main loop status on %lld", (long long)main_now);
385 msg(L_DEBUG, "\tActive timers:");
386 for (uns i = 1; i <= main_timer_cnt; i++)
388 struct main_timer *tm = main_timer_table.ptr[i];
389 msg(L_DEBUG, "\t\t%p (expires %lld, data %p)", tm, (long long)(tm->expires ? tm->expires-main_now : 999999), tm->data);
391 struct main_file *fi;
392 msg(L_DEBUG, "\tActive files:");
393 CLIST_WALK(fi, main_file_list)
394 msg(L_DEBUG, "\t\t%p (fd %d, rh %p, wh %p, eh %p, expires %lld, data %p)",
395 fi, fi->fd, fi->read_handler, fi->write_handler, fi->error_handler,
396 (long long)(fi->timer.expires ? fi->timer.expires-main_now : 999999), fi->data);
397 msg(L_DEBUG, "\tActive hooks:");
398 struct main_hook *ho;
399 CLIST_WALK(ho, main_hook_list)
400 msg(L_DEBUG, "\t\t%p (func %p, data %p)", ho, ho->handler, ho->data);
401 msg(L_DEBUG, "\tActive processes:");
402 struct main_process *pr;
403 CLIST_WALK(pr, main_process_list)
404 msg(L_DEBUG, "\t\t%p (pid %d, data %p)", pr, pr->pid, pr->data);
409 main_rebuild_poll_table(void)
411 struct main_file *fi;
412 if (main_poll_table_size < main_file_cnt)
415 xfree(main_poll_table);
417 main_poll_table_size = 1;
418 while (main_poll_table_size < main_file_cnt)
419 main_poll_table_size *= 2;
420 main_poll_table = xmalloc(sizeof(struct pollfd) * main_poll_table_size);
422 struct pollfd *p = main_poll_table;
423 DBG("MAIN: Rebuilding poll table: %d of %d entries set", main_file_cnt, main_poll_table_size);
424 CLIST_WALK(fi, main_file_list)
430 main_poll_table_obsolete = 0;
436 DBG("MAIN: Entering main_loop");
437 ASSERT(main_hook_list.head.next);
439 struct main_file *fi;
440 struct main_hook *ho;
441 struct main_timer *tm;
442 struct main_process *pr;
447 timestamp_t wake = main_now + 1000000000;
448 while (main_timer_cnt && (tm = main_timer_table.ptr[1])->expires <= main_now)
450 DBG("MAIN: Timer %p expired at now-%lld", tm, (long long)(main_now - tm->expires));
453 int hook_min = HOOK_RETRY;
454 int hook_max = HOOK_SHUTDOWN;
456 clist_init(&hook_done);
457 while (ho = clist_remove_head(&main_hook_list))
459 clist_add_tail(&hook_done, &ho->n);
460 DBG("MAIN: Hook %p", ho);
461 int ret = ho->handler(ho);
462 hook_min = MIN(hook_min, ret);
463 hook_max = MAX(hook_max, ret);
465 clist_move(&main_hook_list, &hook_done);
466 if (hook_min == HOOK_SHUTDOWN ||
467 hook_min == HOOK_DONE && hook_max == HOOK_DONE ||
470 DBG("MAIN: Shut down by %s", main_shutdown ? "main_shutdown" : "a hook");
473 if (hook_max == HOOK_RETRY)
475 if (main_poll_table_obsolete)
476 main_rebuild_poll_table();
477 #ifndef USE_SELF_PIPE
478 // We don't have a reliable flag without the self-pipe.
481 if (chld_received && !clist_empty(&main_process_list))
485 wake = MIN(wake, main_now + 10000);
487 while ((pid = waitpid(-1, &stat, WNOHANG)) > 0)
489 DBG("MAIN: Child %d exited with status %x", pid, stat);
490 CLIST_WALK(pr, main_process_list)
495 format_exit_status(pr->status_msg, pr->status);
496 DBG("MAIN: Calling process exit handler");
503 if (main_timer_cnt && (tm = main_timer_table.ptr[1])->expires < wake)
506 int timeout = ((wake > main_now) ? wake - main_now : 0);
507 DBG("MAIN: Poll for %d fds and timeout %d ms", main_file_cnt, timeout);
508 int p = poll(main_poll_table, main_file_cnt, timeout);
509 timestamp_t old_now = main_now;
511 main_idle_time += main_now - old_now;
514 struct pollfd *p = main_poll_table;
515 CLIST_WALK(fi, main_file_list)
517 if (p->revents & (POLLIN | POLLHUP | POLLERR))
520 DBG("MAIN: Read event on fd %d", p->fd);
521 while (fi->read_handler && fi->read_handler(fi) && !main_poll_table_obsolete);
522 if (main_poll_table_obsolete) /* File entries have been inserted or deleted => better not risk continuing to nowhere */
525 if (p->revents & (POLLOUT | POLLERR))
528 DBG("MAIN: Write event on fd %d", p->fd);
529 while (fi->write_handler && fi->write_handler(fi) && !main_poll_table_obsolete);
530 if (main_poll_table_obsolete)
541 static struct main_process mp;
542 static struct main_file fin, fout;
543 static struct main_hook hook;
544 static struct main_timer tm;
548 static void dread(struct main_file *fi)
550 if (fi->rpos < fi->rlen)
552 msg(L_INFO, "Read EOF");
557 msg(L_INFO, "Read done");
558 file_read(fi, rb, sizeof(rb));
562 static void derror(struct main_file *fi, int cause)
564 msg(L_INFO, "Error: %m !!! (cause %d)", cause);
568 static void dwrite(struct main_file *fi UNUSED)
570 msg(L_INFO, "Write done");
573 static int dhook(struct main_hook *ho UNUSED)
575 msg(L_INFO, "Hook called");
579 static void dtimer(struct main_timer *tm)
581 msg(L_INFO, "Timer tick");
582 timer_add(tm, main_now + 10000);
585 static void dentry(void)
587 msg(L_INFO, "*** SUBPROCESS START ***");
589 msg(L_INFO, "*** SUBPROCESS FINISH ***");
593 static void dexit(struct main_process *pr)
595 msg(L_INFO, "Subprocess %d exited with status %x", pr->pid, pr->status);
605 fin.read_done = dread;
606 fin.error_handler = derror;
608 file_read(&fin, rb, sizeof(rb));
611 fout.write_done = dwrite;
612 fout.error_handler = derror;
614 file_write(&fout, "Hello, world!\n", 14);
616 hook.handler = dhook;
620 timer_add(&tm, main_now + 1000);
623 if (!process_fork(&mp))
629 msg(L_INFO, "Finished.");