2 * uloop - event loop implementation
4 * Copyright (C) 2010-2016 Felix Fietkau <nbd@openwrt.org>
6 * Permission to use, copy, modify, and/or distribute this software for any
7 * purpose with or without fee is hereby granted, provided that the above
8 * copyright notice and this permission notice appear in all copies.
10 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
11 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
13 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
15 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
16 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
19 #include <sys/types.h>
34 #include <sys/event.h>
37 #include <sys/epoll.h>
41 struct uloop_fd_event {
46 struct uloop_fd_stack {
47 struct uloop_fd_stack *next;
52 static struct uloop_fd_stack *fd_stack = NULL;
54 #define ULOOP_MAX_EVENTS 10
56 static struct list_head timeouts = LIST_HEAD_INIT(timeouts);
57 static struct list_head processes = LIST_HEAD_INIT(processes);
59 static int poll_fd = -1;
60 bool uloop_cancelled = false;
61 static int uloop_status = 0;
62 static bool do_sigchld = false;
64 static struct uloop_fd_event cur_fds[ULOOP_MAX_EVENTS];
65 static int cur_fd, cur_nfds;
66 static int uloop_run_depth = 0;
68 int uloop_fd_add(struct uloop_fd *sock, unsigned int flags);
71 #include "uloop-kqueue.c"
75 #include "uloop-epoll.c"
78 static void waker_consume(struct uloop_fd *fd, unsigned int events)
82 while (read(fd->fd, buf, 4) > 0)
86 static int waker_pipe = -1;
87 static struct uloop_fd waker_fd = {
92 static void waker_init_fd(int fd)
94 fcntl(fd, F_SETFD, fcntl(fd, F_GETFD) | FD_CLOEXEC);
95 fcntl(fd, F_SETFL, fcntl(fd, F_GETFL) | O_NONBLOCK);
98 static int waker_init(void)
108 waker_init_fd(fds[0]);
109 waker_init_fd(fds[1]);
112 waker_fd.fd = fds[0];
113 waker_fd.cb = waker_consume;
114 uloop_fd_add(&waker_fd, ULOOP_READ);
119 static void uloop_setup_signals(bool add);
123 if (uloop_init_pollfd() < 0)
126 if (waker_init() < 0) {
131 uloop_setup_signals(true);
136 static bool uloop_fd_stack_event(struct uloop_fd *fd, int events)
138 struct uloop_fd_stack *cur;
141 * Do not buffer events for level-triggered fds, they will keep firing.
142 * Caller needs to take care of recursion issues.
144 if (!(fd->flags & ULOOP_EDGE_TRIGGER))
147 for (cur = fd_stack; cur; cur = cur->next) {
154 cur->events |= events | ULOOP_EVENT_BUFFERED;
162 static void uloop_run_events(int timeout)
164 struct uloop_fd_event *cur;
169 cur_nfds = uloop_fetch_events(timeout);
174 while (cur_nfds > 0) {
175 struct uloop_fd_stack stack_cur;
178 cur = &cur_fds[cur_fd++];
182 events = cur->events;
189 if (uloop_fd_stack_event(fd, cur->events))
192 stack_cur.next = fd_stack;
194 fd_stack = &stack_cur;
196 stack_cur.events = 0;
198 events = stack_cur.events & ULOOP_EVENT_MASK;
199 } while (stack_cur.fd && events);
200 fd_stack = stack_cur.next;
206 int uloop_fd_add(struct uloop_fd *sock, unsigned int flags)
211 if (!(flags & (ULOOP_READ | ULOOP_WRITE)))
212 return uloop_fd_delete(sock);
214 if (!sock->registered && !(flags & ULOOP_BLOCKING)) {
215 fl = fcntl(sock->fd, F_GETFL, 0);
217 fcntl(sock->fd, F_SETFL, fl);
220 ret = register_poll(sock, flags);
224 sock->registered = true;
232 int uloop_fd_delete(struct uloop_fd *fd)
236 for (i = 0; i < cur_nfds; i++) {
237 if (cur_fds[cur_fd + i].fd != fd)
240 cur_fds[cur_fd + i].fd = NULL;
246 fd->registered = false;
247 uloop_fd_stack_event(fd, -1);
248 return __uloop_fd_delete(fd);
251 static int tv_diff(struct timeval *t1, struct timeval *t2)
254 (t1->tv_sec - t2->tv_sec) * 1000 +
255 (t1->tv_usec - t2->tv_usec) / 1000;
258 int uloop_timeout_add(struct uloop_timeout *timeout)
260 struct uloop_timeout *tmp;
261 struct list_head *h = &timeouts;
263 if (timeout->pending)
266 list_for_each_entry(tmp, &timeouts, list) {
267 if (tv_diff(&tmp->time, &timeout->time) > 0) {
273 list_add_tail(&timeout->list, h);
274 timeout->pending = true;
279 static void uloop_gettime(struct timeval *tv)
283 clock_gettime(CLOCK_MONOTONIC, &ts);
284 tv->tv_sec = ts.tv_sec;
285 tv->tv_usec = ts.tv_nsec / 1000;
288 int uloop_timeout_set(struct uloop_timeout *timeout, int msecs)
290 struct timeval *time = &timeout->time;
292 if (timeout->pending)
293 uloop_timeout_cancel(timeout);
297 time->tv_sec += msecs / 1000;
298 time->tv_usec += (msecs % 1000) * 1000;
300 if (time->tv_usec > 1000000) {
302 time->tv_usec -= 1000000;
305 return uloop_timeout_add(timeout);
308 int uloop_timeout_cancel(struct uloop_timeout *timeout)
310 if (!timeout->pending)
313 list_del(&timeout->list);
314 timeout->pending = false;
319 int uloop_timeout_remaining(struct uloop_timeout *timeout)
323 if (!timeout->pending)
328 return tv_diff(&timeout->time, &now);
331 int uloop_process_add(struct uloop_process *p)
333 struct uloop_process *tmp;
334 struct list_head *h = &processes;
339 list_for_each_entry(tmp, &processes, list) {
340 if (tmp->pid > p->pid) {
346 list_add_tail(&p->list, h);
352 int uloop_process_delete(struct uloop_process *p)
363 static void uloop_handle_processes(void)
365 struct uloop_process *p, *tmp;
372 pid = waitpid(-1, &ret, WNOHANG);
373 if (pid < 0 && errno == EINTR)
379 list_for_each_entry_safe(p, tmp, &processes, list) {
386 uloop_process_delete(p);
393 static void uloop_signal_wake(void)
396 if (write(waker_pipe, "w", 1) < 0) {
404 static void uloop_handle_sigint(int signo)
406 uloop_status = signo;
407 uloop_cancelled = true;
411 static void uloop_sigchld(int signo)
417 static void uloop_install_handler(int signum, void (*handler)(int), struct sigaction* old, bool add)
420 struct sigaction *act;
423 sigaction(signum, NULL, &s);
426 if (s.sa_handler == SIG_DFL) { /* Do not override existing custom signal handlers */
427 memcpy(old, &s, sizeof(struct sigaction));
428 s.sa_handler = handler;
433 else if (s.sa_handler == handler) { /* Do not restore if someone modified our handler */
438 sigaction(signum, act, NULL);
441 static void uloop_ignore_signal(int signum, bool ignore)
444 void *new_handler = NULL;
446 sigaction(signum, NULL, &s);
449 if (s.sa_handler == SIG_DFL) /* Ignore only if there isn't any custom handler */
450 new_handler = SIG_IGN;
452 if (s.sa_handler == SIG_IGN) /* Restore only if noone modified our SIG_IGN */
453 new_handler = SIG_DFL;
457 s.sa_handler = new_handler;
459 sigaction(signum, &s, NULL);
463 static void uloop_setup_signals(bool add)
465 static struct sigaction old_sigint, old_sigchld, old_sigterm;
467 uloop_install_handler(SIGINT, uloop_handle_sigint, &old_sigint, add);
468 uloop_install_handler(SIGTERM, uloop_handle_sigint, &old_sigterm, add);
469 uloop_install_handler(SIGCHLD, uloop_sigchld, &old_sigchld, add);
471 uloop_ignore_signal(SIGPIPE, add);
474 static int uloop_get_next_timeout(struct timeval *tv)
476 struct uloop_timeout *timeout;
479 if (list_empty(&timeouts))
482 timeout = list_first_entry(&timeouts, struct uloop_timeout, list);
483 diff = tv_diff(&timeout->time, tv);
490 static void uloop_process_timeouts(struct timeval *tv)
492 struct uloop_timeout *t;
494 while (!list_empty(&timeouts)) {
495 t = list_first_entry(&timeouts, struct uloop_timeout, list);
497 if (tv_diff(&t->time, tv) > 0)
500 uloop_timeout_cancel(t);
506 static void uloop_clear_timeouts(void)
508 struct uloop_timeout *t, *tmp;
510 list_for_each_entry_safe(t, tmp, &timeouts, list)
511 uloop_timeout_cancel(t);
514 static void uloop_clear_processes(void)
516 struct uloop_process *p, *tmp;
518 list_for_each_entry_safe(p, tmp, &processes, list)
519 uloop_process_delete(p);
522 bool uloop_cancelling(void)
524 return uloop_run_depth > 0 && uloop_cancelled;
527 int uloop_run_timeout(int timeout)
535 uloop_cancelled = false;
536 while (!uloop_cancelled)
539 uloop_process_timeouts(&tv);
542 uloop_handle_processes();
549 next_time = uloop_get_next_timeout(&tv);
550 if (timeout >= 0 && timeout < next_time)
552 uloop_run_events(next_time);
560 void uloop_done(void)
562 uloop_setup_signals(false);
569 if (waker_pipe >= 0) {
570 uloop_fd_delete(&waker_fd);
576 uloop_clear_timeouts();
577 uloop_clear_processes();