Mirror of the official OpenWrt libubox repository https://git.openwrt.org/project/libubox
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/*
* uloop - event loop implementation
*
* Copyright (C) 2010-2016 Felix Fietkau <nbd@openwrt.org>
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include <sys/time.h>
#include <sys/types.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <poll.h>
#include <string.h>
#include <fcntl.h>
#include <stdbool.h>
#include "uloop.h"
#include "utils.h"
#ifdef USE_KQUEUE
#include <sys/event.h>
#endif
#ifdef USE_EPOLL
#include <sys/epoll.h>
#endif
#include <sys/wait.h>
struct uloop_fd_event {
struct uloop_fd *fd;
unsigned int events;
};
struct uloop_fd_stack {
struct uloop_fd_stack *next;
struct uloop_fd *fd;
unsigned int events;
};
static struct uloop_fd_stack *fd_stack = NULL;
#define ULOOP_MAX_EVENTS 10
static struct list_head timeouts = LIST_HEAD_INIT(timeouts);
static struct list_head processes = LIST_HEAD_INIT(processes);
static int poll_fd = -1;
bool uloop_cancelled = false;
bool uloop_handle_sigchld = true;
static int uloop_status = 0;
static bool do_sigchld = false;
static struct uloop_fd_event cur_fds[ULOOP_MAX_EVENTS];
static int cur_fd, cur_nfds;
static int uloop_run_depth = 0;
int uloop_fd_add(struct uloop_fd *sock, unsigned int flags);
#ifdef USE_KQUEUE
#include "uloop-kqueue.c"
#endif
#ifdef USE_EPOLL
#include "uloop-epoll.c"
#endif
static void waker_consume(struct uloop_fd *fd, unsigned int events)
{
char buf[4];
while (read(fd->fd, buf, 4) > 0)
;
}
static int waker_pipe = -1;
static struct uloop_fd waker_fd = {
.fd = -1,
.cb = waker_consume,
};
static void waker_init_fd(int fd)
{
fcntl(fd, F_SETFD, fcntl(fd, F_GETFD) | FD_CLOEXEC);
fcntl(fd, F_SETFL, fcntl(fd, F_GETFL) | O_NONBLOCK);
}
static int waker_init(void)
{
int fds[2];
if (waker_pipe >= 0)
return 0;
if (pipe(fds) < 0)
return -1;
waker_init_fd(fds[0]);
waker_init_fd(fds[1]);
waker_pipe = fds[1];
waker_fd.fd = fds[0];
waker_fd.cb = waker_consume;
uloop_fd_add(&waker_fd, ULOOP_READ);
return 0;
}
static void uloop_setup_signals(bool add);
int uloop_init(void)
{
if (uloop_init_pollfd() < 0)
return -1;
if (waker_init() < 0) {
uloop_done();
return -1;
}
uloop_setup_signals(true);
return 0;
}
static bool uloop_fd_stack_event(struct uloop_fd *fd, int events)
{
struct uloop_fd_stack *cur;
/*
* Do not buffer events for level-triggered fds, they will keep firing.
* Caller needs to take care of recursion issues.
*/
if (!(fd->flags & ULOOP_EDGE_TRIGGER))
return false;
for (cur = fd_stack; cur; cur = cur->next) {
if (cur->fd != fd)
continue;
if (events < 0)
cur->fd = NULL;
else
cur->events |= events | ULOOP_EVENT_BUFFERED;
return true;
}
return false;
}
static void uloop_run_events(int timeout)
{
struct uloop_fd_event *cur;
struct uloop_fd *fd;
if (!cur_nfds) {
cur_fd = 0;
cur_nfds = uloop_fetch_events(timeout);
if (cur_nfds < 0)
cur_nfds = 0;
}
while (cur_nfds > 0) {
struct uloop_fd_stack stack_cur;
unsigned int events;
cur = &cur_fds[cur_fd++];
cur_nfds--;
fd = cur->fd;
events = cur->events;
if (!fd)
continue;
if (!fd->cb)
continue;
if (uloop_fd_stack_event(fd, cur->events))
continue;
stack_cur.next = fd_stack;
stack_cur.fd = fd;
fd_stack = &stack_cur;
do {
stack_cur.events = 0;
fd->cb(fd, events);
events = stack_cur.events & ULOOP_EVENT_MASK;
} while (stack_cur.fd && events);
fd_stack = stack_cur.next;
return;
}
}
int uloop_fd_add(struct uloop_fd *sock, unsigned int flags)
{
unsigned int fl;
int ret;
if (!(flags & (ULOOP_READ | ULOOP_WRITE)))
return uloop_fd_delete(sock);
if (!sock->registered && !(flags & ULOOP_BLOCKING)) {
fl = fcntl(sock->fd, F_GETFL, 0);
fl |= O_NONBLOCK;
fcntl(sock->fd, F_SETFL, fl);
}
ret = register_poll(sock, flags);
if (ret < 0)
goto out;
sock->registered = true;
sock->eof = false;
sock->error = false;
out:
return ret;
}
int uloop_fd_delete(struct uloop_fd *fd)
{
int i;
for (i = 0; i < cur_nfds; i++) {
if (cur_fds[cur_fd + i].fd != fd)
continue;
cur_fds[cur_fd + i].fd = NULL;
}
if (!fd->registered)
return 0;
fd->registered = false;
uloop_fd_stack_event(fd, -1);
return __uloop_fd_delete(fd);
}
static int tv_diff(struct timeval *t1, struct timeval *t2)
{
return
(t1->tv_sec - t2->tv_sec) * 1000 +
(t1->tv_usec - t2->tv_usec) / 1000;
}
int uloop_timeout_add(struct uloop_timeout *timeout)
{
struct uloop_timeout *tmp;
struct list_head *h = &timeouts;
if (timeout->pending)
return -1;
list_for_each_entry(tmp, &timeouts, list) {
if (tv_diff(&tmp->time, &timeout->time) > 0) {
h = &tmp->list;
break;
}
}
list_add_tail(&timeout->list, h);
timeout->pending = true;
return 0;
}
static void uloop_gettime(struct timeval *tv)
{
struct timespec ts;
clock_gettime(CLOCK_MONOTONIC, &ts);
tv->tv_sec = ts.tv_sec;
tv->tv_usec = ts.tv_nsec / 1000;
}
int uloop_timeout_set(struct uloop_timeout *timeout, int msecs)
{
struct timeval *time = &timeout->time;
if (timeout->pending)
uloop_timeout_cancel(timeout);
uloop_gettime(time);
time->tv_sec += msecs / 1000;
time->tv_usec += (msecs % 1000) * 1000;
if (time->tv_usec > 1000000) {
time->tv_sec++;
time->tv_usec -= 1000000;
}
return uloop_timeout_add(timeout);
}
int uloop_timeout_cancel(struct uloop_timeout *timeout)
{
if (!timeout->pending)
return -1;
list_del(&timeout->list);
timeout->pending = false;
return 0;
}
int uloop_timeout_remaining(struct uloop_timeout *timeout)
{
struct timeval now;
if (!timeout->pending)
return -1;
uloop_gettime(&now);
return tv_diff(&timeout->time, &now);
}
int uloop_process_add(struct uloop_process *p)
{
struct uloop_process *tmp;
struct list_head *h = &processes;
if (p->pending)
return -1;
list_for_each_entry(tmp, &processes, list) {
if (tmp->pid > p->pid) {
h = &tmp->list;
break;
}
}
list_add_tail(&p->list, h);
p->pending = true;
return 0;
}
int uloop_process_delete(struct uloop_process *p)
{
if (!p->pending)
return -1;
list_del(&p->list);
p->pending = false;
return 0;
}
static void uloop_handle_processes(void)
{
struct uloop_process *p, *tmp;
pid_t pid;
int ret;
do_sigchld = false;
while (1) {
pid = waitpid(-1, &ret, WNOHANG);
if (pid < 0 && errno == EINTR)
continue;
if (pid <= 0)
return;
list_for_each_entry_safe(p, tmp, &processes, list) {
if (p->pid < pid)
continue;
if (p->pid > pid)
break;
uloop_process_delete(p);
p->cb(p, ret);
}
}
}
static void uloop_signal_wake(void)
{
do {
if (write(waker_pipe, "w", 1) < 0) {
if (errno == EINTR)
continue;
}
break;
} while (1);
}
static void uloop_handle_sigint(int signo)
{
uloop_status = signo;
uloop_cancelled = true;
uloop_signal_wake();
}
static void uloop_sigchld(int signo)
{
do_sigchld = true;
uloop_signal_wake();
}
static void uloop_install_handler(int signum, void (*handler)(int), struct sigaction* old, bool add)
{
struct sigaction s;
struct sigaction *act;
act = NULL;
sigaction(signum, NULL, &s);
if (add) {
if (s.sa_handler == SIG_DFL) { /* Do not override existing custom signal handlers */
memcpy(old, &s, sizeof(struct sigaction));
s.sa_handler = handler;
s.sa_flags = 0;
act = &s;
}
}
else if (s.sa_handler == handler) { /* Do not restore if someone modified our handler */
act = old;
}
if (act != NULL)
sigaction(signum, act, NULL);
}
static void uloop_ignore_signal(int signum, bool ignore)
{
struct sigaction s;
void *new_handler = NULL;
sigaction(signum, NULL, &s);
if (ignore) {
if (s.sa_handler == SIG_DFL) /* Ignore only if there isn't any custom handler */
new_handler = SIG_IGN;
} else {
if (s.sa_handler == SIG_IGN) /* Restore only if noone modified our SIG_IGN */
new_handler = SIG_DFL;
}
if (new_handler) {
s.sa_handler = new_handler;
s.sa_flags = 0;
sigaction(signum, &s, NULL);
}
}
static void uloop_setup_signals(bool add)
{
static struct sigaction old_sigint, old_sigchld, old_sigterm;
uloop_install_handler(SIGINT, uloop_handle_sigint, &old_sigint, add);
uloop_install_handler(SIGTERM, uloop_handle_sigint, &old_sigterm, add);
if (uloop_handle_sigchld)
uloop_install_handler(SIGCHLD, uloop_sigchld, &old_sigchld, add);
uloop_ignore_signal(SIGPIPE, add);
}
static int uloop_get_next_timeout(struct timeval *tv)
{
struct uloop_timeout *timeout;
int diff;
if (list_empty(&timeouts))
return -1;
timeout = list_first_entry(&timeouts, struct uloop_timeout, list);
diff = tv_diff(&timeout->time, tv);
if (diff < 0)
return 0;
return diff;
}
static void uloop_process_timeouts(struct timeval *tv)
{
struct uloop_timeout *t;
while (!list_empty(&timeouts)) {
t = list_first_entry(&timeouts, struct uloop_timeout, list);
if (tv_diff(&t->time, tv) > 0)
break;
uloop_timeout_cancel(t);
if (t->cb)
t->cb(t);
}
}
static void uloop_clear_timeouts(void)
{
struct uloop_timeout *t, *tmp;
list_for_each_entry_safe(t, tmp, &timeouts, list)
uloop_timeout_cancel(t);
}
static void uloop_clear_processes(void)
{
struct uloop_process *p, *tmp;
list_for_each_entry_safe(p, tmp, &processes, list)
uloop_process_delete(p);
}
bool uloop_cancelling(void)
{
return uloop_run_depth > 0 && uloop_cancelled;
}
int uloop_run_timeout(int timeout)
{
int next_time = 0;
struct timeval tv;
uloop_run_depth++;
uloop_status = 0;
uloop_cancelled = false;
while (!uloop_cancelled)
{
uloop_gettime(&tv);
uloop_process_timeouts(&tv);
if (do_sigchld)
uloop_handle_processes();
if (uloop_cancelled)
break;
uloop_gettime(&tv);
next_time = uloop_get_next_timeout(&tv);
if (timeout >= 0 && timeout < next_time)
next_time = timeout;
uloop_run_events(next_time);
}
--uloop_run_depth;
return uloop_status;
}
void uloop_done(void)
{
uloop_setup_signals(false);
if (poll_fd >= 0) {
close(poll_fd);
poll_fd = -1;
}
if (waker_pipe >= 0) {
uloop_fd_delete(&waker_fd);
close(waker_pipe);
close(waker_fd.fd);
waker_pipe = -1;
}
uloop_clear_timeouts();
uloop_clear_processes();
}