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);
121 if (uloop_init_pollfd() < 0)
124 if (waker_init() < 0) {
132 static bool uloop_fd_stack_event(struct uloop_fd *fd, int events)
134 struct uloop_fd_stack *cur;
137 * Do not buffer events for level-triggered fds, they will keep firing.
138 * Caller needs to take care of recursion issues.
140 if (!(fd->flags & ULOOP_EDGE_TRIGGER))
143 for (cur = fd_stack; cur; cur = cur->next) {
150 cur->events |= events | ULOOP_EVENT_BUFFERED;
158 static void uloop_run_events(int timeout)
160 struct uloop_fd_event *cur;
165 cur_nfds = uloop_fetch_events(timeout);
170 while (cur_nfds > 0) {
171 struct uloop_fd_stack stack_cur;
174 cur = &cur_fds[cur_fd++];
178 events = cur->events;
185 if (uloop_fd_stack_event(fd, cur->events))
188 stack_cur.next = fd_stack;
190 fd_stack = &stack_cur;
192 stack_cur.events = 0;
194 events = stack_cur.events & ULOOP_EVENT_MASK;
195 } while (stack_cur.fd && events);
196 fd_stack = stack_cur.next;
202 int uloop_fd_add(struct uloop_fd *sock, unsigned int flags)
207 if (!(flags & (ULOOP_READ | ULOOP_WRITE)))
208 return uloop_fd_delete(sock);
210 if (!sock->registered && !(flags & ULOOP_BLOCKING)) {
211 fl = fcntl(sock->fd, F_GETFL, 0);
213 fcntl(sock->fd, F_SETFL, fl);
216 ret = register_poll(sock, flags);
220 sock->registered = true;
228 int uloop_fd_delete(struct uloop_fd *fd)
232 for (i = 0; i < cur_nfds; i++) {
233 if (cur_fds[cur_fd + i].fd != fd)
236 cur_fds[cur_fd + i].fd = NULL;
242 fd->registered = false;
243 uloop_fd_stack_event(fd, -1);
244 return __uloop_fd_delete(fd);
247 static int tv_diff(struct timeval *t1, struct timeval *t2)
250 (t1->tv_sec - t2->tv_sec) * 1000 +
251 (t1->tv_usec - t2->tv_usec) / 1000;
254 int uloop_timeout_add(struct uloop_timeout *timeout)
256 struct uloop_timeout *tmp;
257 struct list_head *h = &timeouts;
259 if (timeout->pending)
262 list_for_each_entry(tmp, &timeouts, list) {
263 if (tv_diff(&tmp->time, &timeout->time) > 0) {
269 list_add_tail(&timeout->list, h);
270 timeout->pending = true;
275 static void uloop_gettime(struct timeval *tv)
279 clock_gettime(CLOCK_MONOTONIC, &ts);
280 tv->tv_sec = ts.tv_sec;
281 tv->tv_usec = ts.tv_nsec / 1000;
284 int uloop_timeout_set(struct uloop_timeout *timeout, int msecs)
286 struct timeval *time = &timeout->time;
288 if (timeout->pending)
289 uloop_timeout_cancel(timeout);
293 time->tv_sec += msecs / 1000;
294 time->tv_usec += (msecs % 1000) * 1000;
296 if (time->tv_usec > 1000000) {
298 time->tv_usec -= 1000000;
301 return uloop_timeout_add(timeout);
304 int uloop_timeout_cancel(struct uloop_timeout *timeout)
306 if (!timeout->pending)
309 list_del(&timeout->list);
310 timeout->pending = false;
315 int uloop_timeout_remaining(struct uloop_timeout *timeout)
319 if (!timeout->pending)
324 return tv_diff(&timeout->time, &now);
327 int uloop_process_add(struct uloop_process *p)
329 struct uloop_process *tmp;
330 struct list_head *h = &processes;
335 list_for_each_entry(tmp, &processes, list) {
336 if (tmp->pid > p->pid) {
342 list_add_tail(&p->list, h);
348 int uloop_process_delete(struct uloop_process *p)
359 static void uloop_handle_processes(void)
361 struct uloop_process *p, *tmp;
368 pid = waitpid(-1, &ret, WNOHANG);
369 if (pid < 0 && errno == EINTR)
375 list_for_each_entry_safe(p, tmp, &processes, list) {
382 uloop_process_delete(p);
389 static void uloop_signal_wake(void)
392 if (write(waker_pipe, "w", 1) < 0) {
400 static void uloop_handle_sigint(int signo)
402 uloop_status = signo;
403 uloop_cancelled = true;
407 static void uloop_sigchld(int signo)
413 static void uloop_install_handler(int signum, void (*handler)(int), struct sigaction* old, bool add)
416 struct sigaction *act;
419 sigaction(signum, NULL, &s);
422 if (s.sa_handler == SIG_DFL) { /* Do not override existing custom signal handlers */
423 memcpy(old, &s, sizeof(struct sigaction));
424 s.sa_handler = handler;
429 else if (s.sa_handler == handler) { /* Do not restore if someone modified our handler */
434 sigaction(signum, act, NULL);
437 static void uloop_ignore_signal(int signum, bool ignore)
440 void *new_handler = NULL;
442 sigaction(signum, NULL, &s);
445 if (s.sa_handler == SIG_DFL) /* Ignore only if there isn't any custom handler */
446 new_handler = SIG_IGN;
448 if (s.sa_handler == SIG_IGN) /* Restore only if noone modified our SIG_IGN */
449 new_handler = SIG_DFL;
453 s.sa_handler = new_handler;
455 sigaction(signum, &s, NULL);
459 static void uloop_setup_signals(bool add)
461 static struct sigaction old_sigint, old_sigchld, old_sigterm;
463 uloop_install_handler(SIGINT, uloop_handle_sigint, &old_sigint, add);
464 uloop_install_handler(SIGTERM, uloop_handle_sigint, &old_sigterm, add);
465 uloop_install_handler(SIGCHLD, uloop_sigchld, &old_sigchld, add);
467 uloop_ignore_signal(SIGPIPE, add);
470 static int uloop_get_next_timeout(struct timeval *tv)
472 struct uloop_timeout *timeout;
475 if (list_empty(&timeouts))
478 timeout = list_first_entry(&timeouts, struct uloop_timeout, list);
479 diff = tv_diff(&timeout->time, tv);
486 static void uloop_process_timeouts(struct timeval *tv)
488 struct uloop_timeout *t;
490 while (!list_empty(&timeouts)) {
491 t = list_first_entry(&timeouts, struct uloop_timeout, list);
493 if (tv_diff(&t->time, tv) > 0)
496 uloop_timeout_cancel(t);
502 static void uloop_clear_timeouts(void)
504 struct uloop_timeout *t, *tmp;
506 list_for_each_entry_safe(t, tmp, &timeouts, list)
507 uloop_timeout_cancel(t);
510 static void uloop_clear_processes(void)
512 struct uloop_process *p, *tmp;
514 list_for_each_entry_safe(p, tmp, &processes, list)
515 uloop_process_delete(p);
518 bool uloop_cancelling(void)
520 return uloop_run_depth > 0 && uloop_cancelled;
523 int uloop_run_timeout(int timeout)
529 * Handlers are only updated for the first call to uloop_run() (and restored
530 * when this call is done).
532 if (!uloop_run_depth++)
533 uloop_setup_signals(true);
536 uloop_cancelled = false;
537 while (!uloop_cancelled)
540 uloop_process_timeouts(&tv);
543 uloop_handle_processes();
550 next_time = uloop_get_next_timeout(&tv);
551 if (timeout > 0 && next_time < timeout)
553 uloop_run_events(timeout);
556 if (!--uloop_run_depth)
557 uloop_setup_signals(false);
562 void uloop_done(void)
569 if (waker_pipe >= 0) {
570 uloop_fd_delete(&waker_fd);
576 uloop_clear_timeouts();
577 uloop_clear_processes();