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]);
109 waker_fd.fd = fds[0];
110 waker_fd.cb = waker_consume;
111 uloop_fd_add(&waker_fd, ULOOP_READ);
118 if (uloop_init_pollfd() < 0)
121 if (waker_init() < 0) {
129 static bool uloop_fd_stack_event(struct uloop_fd *fd, int events)
131 struct uloop_fd_stack *cur;
134 * Do not buffer events for level-triggered fds, they will keep firing.
135 * Caller needs to take care of recursion issues.
137 if (!(fd->flags & ULOOP_EDGE_TRIGGER))
140 for (cur = fd_stack; cur; cur = cur->next) {
147 cur->events |= events | ULOOP_EVENT_BUFFERED;
155 static void uloop_run_events(int timeout)
157 struct uloop_fd_event *cur;
162 cur_nfds = uloop_fetch_events(timeout);
167 while (cur_nfds > 0) {
168 struct uloop_fd_stack stack_cur;
171 cur = &cur_fds[cur_fd++];
175 events = cur->events;
182 if (uloop_fd_stack_event(fd, cur->events))
185 stack_cur.next = fd_stack;
187 fd_stack = &stack_cur;
189 stack_cur.events = 0;
191 events = stack_cur.events & ULOOP_EVENT_MASK;
192 } while (stack_cur.fd && events);
193 fd_stack = stack_cur.next;
199 int uloop_fd_add(struct uloop_fd *sock, unsigned int flags)
204 if (!(flags & (ULOOP_READ | ULOOP_WRITE)))
205 return uloop_fd_delete(sock);
207 if (!sock->registered && !(flags & ULOOP_BLOCKING)) {
208 fl = fcntl(sock->fd, F_GETFL, 0);
210 fcntl(sock->fd, F_SETFL, fl);
213 ret = register_poll(sock, flags);
217 sock->registered = true;
225 int uloop_fd_delete(struct uloop_fd *fd)
229 for (i = 0; i < cur_nfds; i++) {
230 if (cur_fds[cur_fd + i].fd != fd)
233 cur_fds[cur_fd + i].fd = NULL;
239 fd->registered = false;
240 uloop_fd_stack_event(fd, -1);
241 return __uloop_fd_delete(fd);
244 static int tv_diff(struct timeval *t1, struct timeval *t2)
247 (t1->tv_sec - t2->tv_sec) * 1000 +
248 (t1->tv_usec - t2->tv_usec) / 1000;
251 int uloop_timeout_add(struct uloop_timeout *timeout)
253 struct uloop_timeout *tmp;
254 struct list_head *h = &timeouts;
256 if (timeout->pending)
259 list_for_each_entry(tmp, &timeouts, list) {
260 if (tv_diff(&tmp->time, &timeout->time) > 0) {
266 list_add_tail(&timeout->list, h);
267 timeout->pending = true;
272 static void uloop_gettime(struct timeval *tv)
276 clock_gettime(CLOCK_MONOTONIC, &ts);
277 tv->tv_sec = ts.tv_sec;
278 tv->tv_usec = ts.tv_nsec / 1000;
281 int uloop_timeout_set(struct uloop_timeout *timeout, int msecs)
283 struct timeval *time = &timeout->time;
285 if (timeout->pending)
286 uloop_timeout_cancel(timeout);
290 time->tv_sec += msecs / 1000;
291 time->tv_usec += (msecs % 1000) * 1000;
293 if (time->tv_usec > 1000000) {
295 time->tv_usec -= 1000000;
298 return uloop_timeout_add(timeout);
301 int uloop_timeout_cancel(struct uloop_timeout *timeout)
303 if (!timeout->pending)
306 list_del(&timeout->list);
307 timeout->pending = false;
312 int uloop_timeout_remaining(struct uloop_timeout *timeout)
316 if (!timeout->pending)
321 return tv_diff(&timeout->time, &now);
324 int uloop_process_add(struct uloop_process *p)
326 struct uloop_process *tmp;
327 struct list_head *h = &processes;
332 list_for_each_entry(tmp, &processes, list) {
333 if (tmp->pid > p->pid) {
339 list_add_tail(&p->list, h);
345 int uloop_process_delete(struct uloop_process *p)
356 static void uloop_handle_processes(void)
358 struct uloop_process *p, *tmp;
365 pid = waitpid(-1, &ret, WNOHANG);
366 if (pid < 0 && errno == EINTR)
372 list_for_each_entry_safe(p, tmp, &processes, list) {
379 uloop_process_delete(p);
386 static void uloop_signal_wake(void)
388 write(waker_pipe, "w", 1);
391 static void uloop_handle_sigint(int signo)
393 uloop_cancelled = true;
397 static void uloop_sigchld(int signo)
403 static void uloop_install_handler(int signum, void (*handler)(int), struct sigaction* old, bool add)
406 struct sigaction *act;
409 sigaction(signum, NULL, &s);
412 if (s.sa_handler == SIG_DFL) { /* Do not override existing custom signal handlers */
413 memcpy(old, &s, sizeof(struct sigaction));
414 s.sa_handler = handler;
419 else if (s.sa_handler == handler) { /* Do not restore if someone modified our handler */
424 sigaction(signum, act, NULL);
427 static void uloop_ignore_signal(int signum, bool ignore)
430 void *new_handler = NULL;
432 sigaction(signum, NULL, &s);
435 if (s.sa_handler == SIG_DFL) /* Ignore only if there isn't any custom handler */
436 new_handler = SIG_IGN;
438 if (s.sa_handler == SIG_IGN) /* Restore only if noone modified our SIG_IGN */
439 new_handler = SIG_DFL;
443 s.sa_handler = new_handler;
445 sigaction(signum, &s, NULL);
449 static void uloop_setup_signals(bool add)
451 static struct sigaction old_sigint, old_sigchld, old_sigterm;
453 uloop_install_handler(SIGINT, uloop_handle_sigint, &old_sigint, add);
454 uloop_install_handler(SIGTERM, uloop_handle_sigint, &old_sigterm, add);
455 uloop_install_handler(SIGCHLD, uloop_sigchld, &old_sigchld, add);
457 uloop_ignore_signal(SIGPIPE, add);
460 static int uloop_get_next_timeout(struct timeval *tv)
462 struct uloop_timeout *timeout;
465 if (list_empty(&timeouts))
468 timeout = list_first_entry(&timeouts, struct uloop_timeout, list);
469 diff = tv_diff(&timeout->time, tv);
476 static void uloop_process_timeouts(struct timeval *tv)
478 struct uloop_timeout *t;
480 while (!list_empty(&timeouts)) {
481 t = list_first_entry(&timeouts, struct uloop_timeout, list);
483 if (tv_diff(&t->time, tv) > 0)
486 uloop_timeout_cancel(t);
492 static void uloop_clear_timeouts(void)
494 struct uloop_timeout *t, *tmp;
496 list_for_each_entry_safe(t, tmp, &timeouts, list)
497 uloop_timeout_cancel(t);
500 static void uloop_clear_processes(void)
502 struct uloop_process *p, *tmp;
504 list_for_each_entry_safe(p, tmp, &processes, list)
505 uloop_process_delete(p);
510 static int recursive_calls = 0;
514 * Handlers are only updated for the first call to uloop_run() (and restored
515 * when this call is done).
517 if (!recursive_calls++)
518 uloop_setup_signals(true);
520 uloop_cancelled = false;
521 while(!uloop_cancelled)
524 uloop_process_timeouts(&tv);
527 uloop_handle_processes();
533 uloop_run_events(uloop_get_next_timeout(&tv));
536 if (!--recursive_calls)
537 uloop_setup_signals(false);
540 void uloop_done(void)
547 if (waker_pipe >= 0) {
548 uloop_fd_delete(&waker_fd);
554 uloop_clear_timeouts();
555 uloop_clear_processes();