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 bool do_sigchld = false;
63 static struct uloop_fd_event cur_fds[ULOOP_MAX_EVENTS];
64 static int cur_fd, cur_nfds;
66 int uloop_fd_add(struct uloop_fd *sock, unsigned int flags);
69 #include "uloop-kqueue.c"
73 #include "uloop-epoll.c"
76 static void waker_consume(struct uloop_fd *fd, unsigned int events)
80 while (read(fd->fd, buf, 4) > 0)
84 static int waker_pipe = -1;
85 static struct uloop_fd waker_fd = {
90 static void waker_init_fd(int fd)
92 fcntl(fd, F_SETFD, fcntl(fd, F_GETFD) | FD_CLOEXEC);
93 fcntl(fd, F_SETFL, fcntl(fd, F_GETFL) | O_NONBLOCK);
96 static int waker_init(void)
106 waker_init_fd(fds[0]);
107 waker_init_fd(fds[1]);
110 waker_fd.fd = fds[0];
111 waker_fd.cb = waker_consume;
112 uloop_fd_add(&waker_fd, ULOOP_READ);
119 if (uloop_init_pollfd() < 0)
122 if (waker_init() < 0) {
130 static bool uloop_fd_stack_event(struct uloop_fd *fd, int events)
132 struct uloop_fd_stack *cur;
135 * Do not buffer events for level-triggered fds, they will keep firing.
136 * Caller needs to take care of recursion issues.
138 if (!(fd->flags & ULOOP_EDGE_TRIGGER))
141 for (cur = fd_stack; cur; cur = cur->next) {
148 cur->events |= events | ULOOP_EVENT_BUFFERED;
156 static void uloop_run_events(int timeout)
158 struct uloop_fd_event *cur;
163 cur_nfds = uloop_fetch_events(timeout);
168 while (cur_nfds > 0) {
169 struct uloop_fd_stack stack_cur;
172 cur = &cur_fds[cur_fd++];
176 events = cur->events;
183 if (uloop_fd_stack_event(fd, cur->events))
186 stack_cur.next = fd_stack;
188 fd_stack = &stack_cur;
190 stack_cur.events = 0;
192 events = stack_cur.events & ULOOP_EVENT_MASK;
193 } while (stack_cur.fd && events);
194 fd_stack = stack_cur.next;
200 int uloop_fd_add(struct uloop_fd *sock, unsigned int flags)
205 if (!(flags & (ULOOP_READ | ULOOP_WRITE)))
206 return uloop_fd_delete(sock);
208 if (!sock->registered && !(flags & ULOOP_BLOCKING)) {
209 fl = fcntl(sock->fd, F_GETFL, 0);
211 fcntl(sock->fd, F_SETFL, fl);
214 ret = register_poll(sock, flags);
218 sock->registered = true;
226 int uloop_fd_delete(struct uloop_fd *fd)
230 for (i = 0; i < cur_nfds; i++) {
231 if (cur_fds[cur_fd + i].fd != fd)
234 cur_fds[cur_fd + i].fd = NULL;
240 fd->registered = false;
241 uloop_fd_stack_event(fd, -1);
242 return __uloop_fd_delete(fd);
245 static int tv_diff(struct timeval *t1, struct timeval *t2)
248 (t1->tv_sec - t2->tv_sec) * 1000 +
249 (t1->tv_usec - t2->tv_usec) / 1000;
252 int uloop_timeout_add(struct uloop_timeout *timeout)
254 struct uloop_timeout *tmp;
255 struct list_head *h = &timeouts;
257 if (timeout->pending)
260 list_for_each_entry(tmp, &timeouts, list) {
261 if (tv_diff(&tmp->time, &timeout->time) > 0) {
267 list_add_tail(&timeout->list, h);
268 timeout->pending = true;
273 static void uloop_gettime(struct timeval *tv)
277 clock_gettime(CLOCK_MONOTONIC, &ts);
278 tv->tv_sec = ts.tv_sec;
279 tv->tv_usec = ts.tv_nsec / 1000;
282 int uloop_timeout_set(struct uloop_timeout *timeout, int msecs)
284 struct timeval *time = &timeout->time;
286 if (timeout->pending)
287 uloop_timeout_cancel(timeout);
291 time->tv_sec += msecs / 1000;
292 time->tv_usec += (msecs % 1000) * 1000;
294 if (time->tv_usec > 1000000) {
296 time->tv_usec -= 1000000;
299 return uloop_timeout_add(timeout);
302 int uloop_timeout_cancel(struct uloop_timeout *timeout)
304 if (!timeout->pending)
307 list_del(&timeout->list);
308 timeout->pending = false;
313 int uloop_timeout_remaining(struct uloop_timeout *timeout)
317 if (!timeout->pending)
322 return tv_diff(&timeout->time, &now);
325 int uloop_process_add(struct uloop_process *p)
327 struct uloop_process *tmp;
328 struct list_head *h = &processes;
333 list_for_each_entry(tmp, &processes, list) {
334 if (tmp->pid > p->pid) {
340 list_add_tail(&p->list, h);
346 int uloop_process_delete(struct uloop_process *p)
357 static void uloop_handle_processes(void)
359 struct uloop_process *p, *tmp;
366 pid = waitpid(-1, &ret, WNOHANG);
367 if (pid < 0 && errno == EINTR)
373 list_for_each_entry_safe(p, tmp, &processes, list) {
380 uloop_process_delete(p);
387 static void uloop_signal_wake(void)
389 write(waker_pipe, "w", 1);
392 static void uloop_handle_sigint(int signo)
394 uloop_cancelled = true;
398 static void uloop_sigchld(int signo)
404 static void uloop_install_handler(int signum, void (*handler)(int), struct sigaction* old, bool add)
407 struct sigaction *act;
410 sigaction(signum, NULL, &s);
413 if (s.sa_handler == SIG_DFL) { /* Do not override existing custom signal handlers */
414 memcpy(old, &s, sizeof(struct sigaction));
415 s.sa_handler = handler;
420 else if (s.sa_handler == handler) { /* Do not restore if someone modified our handler */
425 sigaction(signum, act, NULL);
428 static void uloop_ignore_signal(int signum, bool ignore)
431 void *new_handler = NULL;
433 sigaction(signum, NULL, &s);
436 if (s.sa_handler == SIG_DFL) /* Ignore only if there isn't any custom handler */
437 new_handler = SIG_IGN;
439 if (s.sa_handler == SIG_IGN) /* Restore only if noone modified our SIG_IGN */
440 new_handler = SIG_DFL;
444 s.sa_handler = new_handler;
446 sigaction(signum, &s, NULL);
450 static void uloop_setup_signals(bool add)
452 static struct sigaction old_sigint, old_sigchld, old_sigterm;
454 uloop_install_handler(SIGINT, uloop_handle_sigint, &old_sigint, add);
455 uloop_install_handler(SIGTERM, uloop_handle_sigint, &old_sigterm, add);
456 uloop_install_handler(SIGCHLD, uloop_sigchld, &old_sigchld, add);
458 uloop_ignore_signal(SIGPIPE, add);
461 static int uloop_get_next_timeout(struct timeval *tv)
463 struct uloop_timeout *timeout;
466 if (list_empty(&timeouts))
469 timeout = list_first_entry(&timeouts, struct uloop_timeout, list);
470 diff = tv_diff(&timeout->time, tv);
477 static void uloop_process_timeouts(struct timeval *tv)
479 struct uloop_timeout *t;
481 while (!list_empty(&timeouts)) {
482 t = list_first_entry(&timeouts, struct uloop_timeout, list);
484 if (tv_diff(&t->time, tv) > 0)
487 uloop_timeout_cancel(t);
493 static void uloop_clear_timeouts(void)
495 struct uloop_timeout *t, *tmp;
497 list_for_each_entry_safe(t, tmp, &timeouts, list)
498 uloop_timeout_cancel(t);
501 static void uloop_clear_processes(void)
503 struct uloop_process *p, *tmp;
505 list_for_each_entry_safe(p, tmp, &processes, list)
506 uloop_process_delete(p);
511 static int recursive_calls = 0;
515 * Handlers are only updated for the first call to uloop_run() (and restored
516 * when this call is done).
518 if (!recursive_calls++)
519 uloop_setup_signals(true);
521 uloop_cancelled = false;
522 while(!uloop_cancelled)
525 uloop_process_timeouts(&tv);
528 uloop_handle_processes();
534 uloop_run_events(uloop_get_next_timeout(&tv));
537 if (!--recursive_calls)
538 uloop_setup_signals(false);
541 void uloop_done(void)
548 if (waker_pipe >= 0) {
549 uloop_fd_delete(&waker_fd);
555 uloop_clear_timeouts();
556 uloop_clear_processes();