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();