blob: 8df18dd7737236b2f3fa0956d025d912cfcd90c1 [file] [log] [blame]
/***
This file is part of avahi.
avahi is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as
published by the Free Software Foundation; either version 2.1 of the
License, or (at your option) any later version.
avahi is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General
Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with avahi; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
USA.
***/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <sys/poll.h>
#include <assert.h>
#include <string.h>
#include <errno.h>
#include <unistd.h>
#include <fcntl.h>
#include <stdio.h>
#include "llist.h"
#include "malloc.h"
#include "timeval.h"
#include "simple-watch.h"
struct AvahiWatch {
AvahiSimplePoll *simple_poll;
int dead;
int idx;
struct pollfd pollfd;
AvahiWatchCallback callback;
void *userdata;
AVAHI_LLIST_FIELDS(AvahiWatch, watches);
};
struct AvahiTimeout {
AvahiSimplePoll *simple_poll;
int dead;
int enabled;
struct timeval expiry;
AvahiTimeoutCallback callback;
void *userdata;
AVAHI_LLIST_FIELDS(AvahiTimeout, timeouts);
};
struct AvahiSimplePoll {
AvahiPoll api;
AvahiPollFunc poll_func;
void *poll_func_userdata;
struct pollfd* pollfds;
int n_pollfds, max_pollfds, rebuild_pollfds;
int watch_req_cleanup, timeout_req_cleanup;
int quit;
int events_valid;
int n_watches;
AVAHI_LLIST_HEAD(AvahiWatch, watches);
AVAHI_LLIST_HEAD(AvahiTimeout, timeouts);
int wakeup_pipe[2];
int wakeup_issued;
int prepared_timeout;
enum {
STATE_INIT,
STATE_PREPARING,
STATE_PREPARED,
STATE_RUNNING,
STATE_RAN,
STATE_DISPATCHING,
STATE_DISPATCHED,
STATE_QUIT,
STATE_FAILURE
} state;
};
void avahi_simple_poll_wakeup(AvahiSimplePoll *s) {
char c = 'W';
assert(s);
write(s->wakeup_pipe[1], &c, sizeof(c));
s->wakeup_issued = 1;
}
static void clear_wakeup(AvahiSimplePoll *s) {
char c[10]; /* Read ten at a time */
if (!s->wakeup_issued)
return;
s->wakeup_issued = 0;
for(;;)
if (read(s->wakeup_pipe[0], &c, sizeof(c)) != sizeof(c))
break;
}
static int set_nonblock(int fd) {
int n;
assert(fd >= 0);
if ((n = fcntl(fd, F_GETFL)) < 0)
return -1;
if (n & O_NONBLOCK)
return 0;
return fcntl(fd, F_SETFL, n|O_NONBLOCK);
}
static AvahiWatch* watch_new(const AvahiPoll *api, int fd, AvahiWatchEvent event, AvahiWatchCallback callback, void *userdata) {
AvahiWatch *w;
AvahiSimplePoll *s;
assert(api);
assert(fd >= 0);
assert(callback);
s = api->userdata;
assert(s);
if (!(w = avahi_new(AvahiWatch, 1)))
return NULL;
/* If there is a background thread running the poll() for us, tell it to exit the poll() */
avahi_simple_poll_wakeup(s);
w->simple_poll = s;
w->dead = 0;
w->pollfd.fd = fd;
w->pollfd.events = event;
w->pollfd.revents = 0;
w->callback = callback;
w->userdata = userdata;
w->idx = -1;
s->rebuild_pollfds = 1;
AVAHI_LLIST_PREPEND(AvahiWatch, watches, s->watches, w);
s->n_watches++;
return w;
}
static void watch_update(AvahiWatch *w, AvahiWatchEvent events) {
assert(w);
assert(!w->dead);
/* If there is a background thread running the poll() for us, tell it to exit the poll() */
avahi_simple_poll_wakeup(w->simple_poll);
w->pollfd.events = events;
if (w->idx != -1) {
assert(w->simple_poll);
w->simple_poll->pollfds[w->idx] = w->pollfd;
} else
w->simple_poll->rebuild_pollfds = 1;
}
static AvahiWatchEvent watch_get_events(AvahiWatch *w) {
assert(w);
assert(!w->dead);
if (w->idx != -1 && w->simple_poll->events_valid)
return w->simple_poll->pollfds[w->idx].revents;
return 0;
}
static void remove_pollfd(AvahiWatch *w) {
assert(w);
if (w->idx == -1)
return;
w->simple_poll->rebuild_pollfds = 1;
}
static void watch_free(AvahiWatch *w) {
assert(w);
assert(!w->dead);
/* If there is a background thread running the poll() for us, tell it to exit the poll() */
avahi_simple_poll_wakeup(w->simple_poll);
remove_pollfd(w);
w->dead = 1;
w->simple_poll->n_watches --;
w->simple_poll->watch_req_cleanup = 1;
}
static void destroy_watch(AvahiWatch *w) {
assert(w);
remove_pollfd(w);
AVAHI_LLIST_REMOVE(AvahiWatch, watches, w->simple_poll->watches, w);
if (!w->dead)
w->simple_poll->n_watches --;
avahi_free(w);
}
static void cleanup_watches(AvahiSimplePoll *s, int all) {
AvahiWatch *w, *next;
assert(s);
for (w = s->watches; w; w = next) {
next = w->watches_next;
if (all || w->dead)
destroy_watch(w);
}
s->timeout_req_cleanup = 0;
}
static AvahiTimeout* timeout_new(const AvahiPoll *api, const struct timeval *tv, AvahiTimeoutCallback callback, void *userdata) {
AvahiTimeout *t;
AvahiSimplePoll *s;
assert(api);
assert(callback);
s = api->userdata;
assert(s);
if (!(t = avahi_new(AvahiTimeout, 1)))
return NULL;
/* If there is a background thread running the poll() for us, tell it to exit the poll() */
avahi_simple_poll_wakeup(s);
t->simple_poll = s;
t->dead = 0;
if ((t->enabled = !!tv))
t->expiry = *tv;
t->callback = callback;
t->userdata = userdata;
AVAHI_LLIST_PREPEND(AvahiTimeout, timeouts, s->timeouts, t);
return t;
}
static void timeout_update(AvahiTimeout *t, const struct timeval *tv) {
assert(t);
assert(!t->dead);
/* If there is a background thread running the poll() for us, tell it to exit the poll() */
avahi_simple_poll_wakeup(t->simple_poll);
if ((t->enabled = !!tv))
t->expiry = *tv;
}
static void timeout_free(AvahiTimeout *t) {
assert(t);
assert(!t->dead);
/* If there is a background thread running the poll() for us, tell it to exit the poll() */
avahi_simple_poll_wakeup(t->simple_poll);
t->dead = 1;
t->simple_poll->timeout_req_cleanup = 1;
}
static void destroy_timeout(AvahiTimeout *t) {
assert(t);
AVAHI_LLIST_REMOVE(AvahiTimeout, timeouts, t->simple_poll->timeouts, t);
avahi_free(t);
}
static void cleanup_timeouts(AvahiSimplePoll *s, int all) {
AvahiTimeout *t, *next;
assert(s);
for (t = s->timeouts; t; t = next) {
next = t->timeouts_next;
if (all || t->dead)
destroy_timeout(t);
}
s->timeout_req_cleanup = 0;
}
AvahiSimplePoll *avahi_simple_poll_new(void) {
AvahiSimplePoll *s;
if (!(s = avahi_new(AvahiSimplePoll, 1)))
return NULL;
if (pipe(s->wakeup_pipe) < 0) {
avahi_free(s);
return NULL;
}
set_nonblock(s->wakeup_pipe[0]);
set_nonblock(s->wakeup_pipe[1]);
s->api.userdata = s;
s->api.watch_new = watch_new;
s->api.watch_free = watch_free;
s->api.watch_update = watch_update;
s->api.watch_get_events = watch_get_events;
s->api.timeout_new = timeout_new;
s->api.timeout_free = timeout_free;
s->api.timeout_update = timeout_update;
s->pollfds = NULL;
s->max_pollfds = s->n_pollfds = 0;
s->rebuild_pollfds = 1;
s->quit = 0;
s->n_watches = 0;
s->events_valid = 0;
s->watch_req_cleanup = 0;
s->timeout_req_cleanup = 0;
s->prepared_timeout = 0;
s->state = STATE_INIT;
s->wakeup_issued = 0;
avahi_simple_poll_set_func(s, NULL, NULL);
AVAHI_LLIST_HEAD_INIT(AvahiWatch, s->watches);
AVAHI_LLIST_HEAD_INIT(AvahiTimeout, s->timeouts);
return s;
}
void avahi_simple_poll_free(AvahiSimplePoll *s) {
assert(s);
cleanup_timeouts(s, 1);
cleanup_watches(s, 1);
assert(s->n_watches == 0);
avahi_free(s->pollfds);
if (s->wakeup_pipe[0] >= 0)
close(s->wakeup_pipe[0]);
if (s->wakeup_pipe[1] >= 0)
close(s->wakeup_pipe[1]);
avahi_free(s);
}
static int rebuild(AvahiSimplePoll *s) {
AvahiWatch *w;
int idx;
assert(s);
if (s->n_watches+1 > s->max_pollfds) {
struct pollfd *n;
s->max_pollfds = s->n_watches + 10;
if (!(n = avahi_realloc(s->pollfds, sizeof(struct pollfd) * s->max_pollfds)))
return -1;
s->pollfds = n;
}
s->pollfds[0].fd = s->wakeup_pipe[0];
s->pollfds[0].events = POLLIN;
s->pollfds[0].revents = 0;
idx = 1;
for (w = s->watches; w; w = w->watches_next) {
if(w->dead)
continue;
assert(w->idx < s->max_pollfds);
s->pollfds[w->idx = idx++] = w->pollfd;
}
s->n_pollfds = idx;
s->events_valid = 0;
s->rebuild_pollfds = 0;
return 0;
}
static AvahiTimeout* find_next_timeout(AvahiSimplePoll *s) {
AvahiTimeout *t, *n = NULL;
assert(s);
for (t = s->timeouts; t; t = t->timeouts_next) {
if (t->dead || !t->enabled)
continue;
if (!n || avahi_timeval_compare(&t->expiry, &n->expiry) < 0)
n = t;
}
return n;
}
static void timeout_callback(AvahiTimeout *t) {
assert(t);
assert(!t->dead);
assert(t->enabled);
t->enabled = 0;
t->callback(t, t->userdata);
}
int avahi_simple_poll_prepare(AvahiSimplePoll *s, int timeout) {
AvahiTimeout *next_timeout;
assert(s);
assert(s->state == STATE_INIT || s->state == STATE_DISPATCHED || s->state == STATE_FAILURE);
s->state = STATE_PREPARING;
/* Clear pending wakeup requests */
clear_wakeup(s);
/* Cleanup things first */
if (s->watch_req_cleanup)
cleanup_watches(s, 0);
if (s->timeout_req_cleanup)
cleanup_timeouts(s, 0);
/* Check whether a quit was requested */
if (s->quit) {
s->state = STATE_QUIT;
return 1;
}
/* Do we need to rebuild our array of pollfds? */
if (s->rebuild_pollfds)
if (rebuild(s) < 0) {
s->state = STATE_FAILURE;
return -1;
}
/* Calculate the wakeup time */
if ((next_timeout = find_next_timeout(s))) {
struct timeval now;
int t;
AvahiUsec usec;
if (next_timeout->expiry.tv_sec == 0 &&
next_timeout->expiry.tv_usec == 0) {
/* Just a shortcut so that we don't need to call gettimeofday() */
timeout = 0;
goto finish;
}
gettimeofday(&now, NULL);
usec = avahi_timeval_diff(&next_timeout->expiry, &now);
if (usec <= 0) {
/* Timeout elapsed */
timeout = 0;
goto finish;
}
/* Calculate sleep time. We add 1ms because otherwise we'd
* wake up too early most of the time */
t = (int) (usec / 1000) + 1;
if (timeout < 0 || timeout > t)
timeout = t;
}
finish:
s->prepared_timeout = timeout;
s->state = STATE_PREPARED;
return 0;
}
int avahi_simple_poll_run(AvahiSimplePoll *s) {
assert(s);
assert(s->state == STATE_PREPARED || s->state == STATE_FAILURE);
s->state = STATE_RUNNING;
for (;;) {
errno = 0;
if (s->poll_func(s->pollfds, s->n_pollfds, s->prepared_timeout, s->poll_func_userdata) < 0) {
if (errno == EINTR)
continue;
s->state = STATE_FAILURE;
return -1;
}
break;
}
/* The poll events are now valid again */
s->events_valid = 1;
/* Update state */
s->state = STATE_RAN;
return 0;
}
int avahi_simple_poll_dispatch(AvahiSimplePoll *s) {
AvahiTimeout *next_timeout;
AvahiWatch *w;
assert(s);
assert(s->state == STATE_RAN);
s->state = STATE_DISPATCHING;
/* We execute only on callback in every iteration */
/* Check whether the wakeup time has been reached now */
if ((next_timeout = find_next_timeout(s))) {
if (next_timeout->expiry.tv_sec == 0 && next_timeout->expiry.tv_usec == 0) {
/* Just a shortcut so that we don't need to call gettimeofday() */
timeout_callback(next_timeout);
goto finish;
}
if (avahi_age(&next_timeout->expiry) >= 0) {
/* Timeout elapsed */
timeout_callback(next_timeout);
goto finish;
}
}
/* Look for some kind of I/O event */
for (w = s->watches; w; w = w->watches_next) {
if (w->dead)
continue;
assert(w->idx >= 0);
assert(w->idx < s->n_pollfds);
if (s->pollfds[w->idx].revents != 0) {
w->callback(w, w->pollfd.fd, s->pollfds[w->idx].revents, w->userdata);
goto finish;
}
}
finish:
s->state = STATE_DISPATCHED;
return 0;
}
int avahi_simple_poll_iterate(AvahiSimplePoll *s, int timeout) {
int r;
if ((r = avahi_simple_poll_prepare(s, timeout)) != 0)
return r;
if ((r = avahi_simple_poll_run(s)) != 0)
return r;
if ((r = avahi_simple_poll_dispatch(s)) != 0)
return r;
return 0;
}
void avahi_simple_poll_quit(AvahiSimplePoll *s) {
assert(s);
s->quit = 1;
/* If there is a background thread running the poll() for us, tell it to exit the poll() */
avahi_simple_poll_wakeup(s);
}
const AvahiPoll* avahi_simple_poll_get(AvahiSimplePoll *s) {
assert(s);
return &s->api;
}
static int system_poll(struct pollfd *ufds, unsigned int nfds, int timeout, AVAHI_GCC_UNUSED void *userdata) {
return poll(ufds, nfds, timeout);
}
void avahi_simple_poll_set_func(AvahiSimplePoll *s, AvahiPollFunc func, void *userdata) {
assert(s);
s->poll_func = func ? func : system_poll;
s->poll_func_userdata = func ? userdata : NULL;
/* If there is a background thread running the poll() for us, tell it to exit the poll() */
avahi_simple_poll_wakeup(s);
}
int avahi_simple_poll_loop(AvahiSimplePoll *s) {
int r;
assert(s);
for (;;)
if ((r = avahi_simple_poll_iterate(s, -1)) != 0)
if (r >= 0 || errno != EINTR)
return r;
}