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;
67 int uloop_fd_add(struct uloop_fd *sock, unsigned int flags);
70 #include "uloop-kqueue.c"
74 #include "uloop-epoll.c"
77 static void waker_consume(struct uloop_fd *fd, unsigned int events)
81 while (read(fd->fd, buf, 4) > 0)
85 static int waker_pipe = -1;
86 static struct uloop_fd waker_fd = {
91 static void waker_init_fd(int fd)
93 fcntl(fd, F_SETFD, fcntl(fd, F_GETFD) | FD_CLOEXEC);
94 fcntl(fd, F_SETFL, fcntl(fd, F_GETFL) | O_NONBLOCK);
97 static int waker_init(void)
107 waker_init_fd(fds[0]);
108 waker_init_fd(fds[1]);
111 waker_fd.fd = fds[0];
112 waker_fd.cb = waker_consume;
113 uloop_fd_add(&waker_fd, ULOOP_READ);
120 if (uloop_init_pollfd() < 0)
123 if (waker_init() < 0) {
131 static bool uloop_fd_stack_event(struct uloop_fd *fd, int events)
133 struct uloop_fd_stack *cur;
136 * Do not buffer events for level-triggered fds, they will keep firing.
137 * Caller needs to take care of recursion issues.
139 if (!(fd->flags & ULOOP_EDGE_TRIGGER))
142 for (cur = fd_stack; cur; cur = cur->next) {
149 cur->events |= events | ULOOP_EVENT_BUFFERED;
157 static void uloop_run_events(int timeout)
159 struct uloop_fd_event *cur;
164 cur_nfds = uloop_fetch_events(timeout);
169 while (cur_nfds > 0) {
170 struct uloop_fd_stack stack_cur;
173 cur = &cur_fds[cur_fd++];
177 events = cur->events;
184 if (uloop_fd_stack_event(fd, cur->events))
187 stack_cur.next = fd_stack;
189 fd_stack = &stack_cur;
191 stack_cur.events = 0;
193 events = stack_cur.events & ULOOP_EVENT_MASK;
194 } while (stack_cur.fd && events);
195 fd_stack = stack_cur.next;
201 int uloop_fd_add(struct uloop_fd *sock, unsigned int flags)
206 if (!(flags & (ULOOP_READ | ULOOP_WRITE)))
207 return uloop_fd_delete(sock);
209 if (!sock->registered && !(flags & ULOOP_BLOCKING)) {
210 fl = fcntl(sock->fd, F_GETFL, 0);
212 fcntl(sock->fd, F_SETFL, fl);
215 ret = register_poll(sock, flags);
219 sock->registered = true;
227 int uloop_fd_delete(struct uloop_fd *fd)
231 for (i = 0; i < cur_nfds; i++) {
232 if (cur_fds[cur_fd + i].fd != fd)
235 cur_fds[cur_fd + i].fd = NULL;
241 fd->registered = false;
242 uloop_fd_stack_event(fd, -1);
243 return __uloop_fd_delete(fd);
246 static int tv_diff(struct timeval *t1, struct timeval *t2)
249 (t1->tv_sec - t2->tv_sec) * 1000 +
250 (t1->tv_usec - t2->tv_usec) / 1000;
253 int uloop_timeout_add(struct uloop_timeout *timeout)
255 struct uloop_timeout *tmp;
256 struct list_head *h = &timeouts;
258 if (timeout->pending)
261 list_for_each_entry(tmp, &timeouts, list) {
262 if (tv_diff(&tmp->time, &timeout->time) > 0) {
268 list_add_tail(&timeout->list, h);
269 timeout->pending = true;
274 static void uloop_gettime(struct timeval *tv)
278 clock_gettime(CLOCK_MONOTONIC, &ts);
279 tv->tv_sec = ts.tv_sec;
280 tv->tv_usec = ts.tv_nsec / 1000;
283 int uloop_timeout_set(struct uloop_timeout *timeout, int msecs)
285 struct timeval *time = &timeout->time;
287 if (timeout->pending)
288 uloop_timeout_cancel(timeout);
292 time->tv_sec += msecs / 1000;
293 time->tv_usec += (msecs % 1000) * 1000;
295 if (time->tv_usec > 1000000) {
297 time->tv_usec -= 1000000;
300 return uloop_timeout_add(timeout);
303 int uloop_timeout_cancel(struct uloop_timeout *timeout)
305 if (!timeout->pending)
308 list_del(&timeout->list);
309 timeout->pending = false;
314 int uloop_timeout_remaining(struct uloop_timeout *timeout)
318 if (!timeout->pending)
323 return tv_diff(&timeout->time, &now);
326 int uloop_process_add(struct uloop_process *p)
328 struct uloop_process *tmp;
329 struct list_head *h = &processes;
334 list_for_each_entry(tmp, &processes, list) {
335 if (tmp->pid > p->pid) {
341 list_add_tail(&p->list, h);
347 int uloop_process_delete(struct uloop_process *p)
358 static void uloop_handle_processes(void)
360 struct uloop_process *p, *tmp;
367 pid = waitpid(-1, &ret, WNOHANG);
368 if (pid < 0 && errno == EINTR)
374 list_for_each_entry_safe(p, tmp, &processes, list) {
381 uloop_process_delete(p);
388 static void uloop_signal_wake(void)
391 if (write(waker_pipe, "w", 1) < 0) {
399 static void uloop_handle_sigint(int signo)
401 uloop_status = signo;
402 uloop_cancelled = true;
406 static void uloop_sigchld(int signo)
412 static void uloop_install_handler(int signum, void (*handler)(int), struct sigaction* old, bool add)
415 struct sigaction *act;
418 sigaction(signum, NULL, &s);
421 if (s.sa_handler == SIG_DFL) { /* Do not override existing custom signal handlers */
422 memcpy(old, &s, sizeof(struct sigaction));
423 s.sa_handler = handler;
428 else if (s.sa_handler == handler) { /* Do not restore if someone modified our handler */
433 sigaction(signum, act, NULL);
436 static void uloop_ignore_signal(int signum, bool ignore)
439 void *new_handler = NULL;
441 sigaction(signum, NULL, &s);
444 if (s.sa_handler == SIG_DFL) /* Ignore only if there isn't any custom handler */
445 new_handler = SIG_IGN;
447 if (s.sa_handler == SIG_IGN) /* Restore only if noone modified our SIG_IGN */
448 new_handler = SIG_DFL;
452 s.sa_handler = new_handler;
454 sigaction(signum, &s, NULL);
458 static void uloop_setup_signals(bool add)
460 static struct sigaction old_sigint, old_sigchld, old_sigterm;
462 uloop_install_handler(SIGINT, uloop_handle_sigint, &old_sigint, add);
463 uloop_install_handler(SIGTERM, uloop_handle_sigint, &old_sigterm, add);
464 uloop_install_handler(SIGCHLD, uloop_sigchld, &old_sigchld, add);
466 uloop_ignore_signal(SIGPIPE, add);
469 static int uloop_get_next_timeout(struct timeval *tv)
471 struct uloop_timeout *timeout;
474 if (list_empty(&timeouts))
477 timeout = list_first_entry(&timeouts, struct uloop_timeout, list);
478 diff = tv_diff(&timeout->time, tv);
485 static void uloop_process_timeouts(struct timeval *tv)
487 struct uloop_timeout *t;
489 while (!list_empty(&timeouts)) {
490 t = list_first_entry(&timeouts, struct uloop_timeout, list);
492 if (tv_diff(&t->time, tv) > 0)
495 uloop_timeout_cancel(t);
501 static void uloop_clear_timeouts(void)
503 struct uloop_timeout *t, *tmp;
505 list_for_each_entry_safe(t, tmp, &timeouts, list)
506 uloop_timeout_cancel(t);
509 static void uloop_clear_processes(void)
511 struct uloop_process *p, *tmp;
513 list_for_each_entry_safe(p, tmp, &processes, list)
514 uloop_process_delete(p);
519 static int recursive_calls = 0;
523 * Handlers are only updated for the first call to uloop_run() (and restored
524 * when this call is done).
526 if (!recursive_calls++)
527 uloop_setup_signals(true);
530 uloop_cancelled = false;
531 while (!uloop_cancelled)
534 uloop_process_timeouts(&tv);
537 uloop_handle_processes();
543 uloop_run_events(uloop_get_next_timeout(&tv));
546 if (!--recursive_calls)
547 uloop_setup_signals(false);
552 void uloop_done(void)
559 if (waker_pipe >= 0) {
560 uloop_fd_delete(&waker_fd);
566 uloop_clear_timeouts();
567 uloop_clear_processes();