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/* select filedescriptor handling, taken from:
* userspace logging daemon for the iptables ULOG target
* of the linux 2.4 netfilter subsystem.
*
* (C) 2000-2009 by Harald Welte <laforge@gnumonks.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2
* as published by the Free Software Foundation
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <fcntl.h>
#include <osmocore/select.h>
#include <osmocore/linuxlist.h>
#include <osmocore/timer.h>
#include "../config.h"
#ifdef HAVE_SYS_SELECT_H
static int maxfd = 0;
static LLIST_HEAD(bsc_fds);
static int unregistered_count;
int bsc_register_fd(struct bsc_fd *fd)
{
int flags;
/* make FD nonblocking */
flags = fcntl(fd->fd, F_GETFL);
if (flags < 0)
return flags;
flags |= O_NONBLOCK;
flags = fcntl(fd->fd, F_SETFL, flags);
if (flags < 0)
return flags;
/* Register FD */
if (fd->fd > maxfd)
maxfd = fd->fd;
llist_add_tail(&fd->list, &bsc_fds);
return 0;
}
void bsc_unregister_fd(struct bsc_fd *fd)
{
unregistered_count++;
llist_del(&fd->list);
}
int bsc_select_main(int polling)
{
struct bsc_fd *ufd, *tmp;
fd_set readset, writeset, exceptset;
int work = 0, rc;
struct timeval no_time = {0, 0};
FD_ZERO(&readset);
FD_ZERO(&writeset);
FD_ZERO(&exceptset);
/* prepare read and write fdsets */
llist_for_each_entry(ufd, &bsc_fds, list) {
if (ufd->when & BSC_FD_READ)
FD_SET(ufd->fd, &readset);
if (ufd->when & BSC_FD_WRITE)
FD_SET(ufd->fd, &writeset);
if (ufd->when & BSC_FD_EXCEPT)
FD_SET(ufd->fd, &exceptset);
}
bsc_timer_check();
if (!polling)
bsc_prepare_timers();
rc = select(maxfd+1, &readset, &writeset, &exceptset, polling ? &no_time : bsc_nearest_timer());
if (rc < 0)
return 0;
/* fire timers */
bsc_update_timers();
/* call registered callback functions */
restart:
unregistered_count = 0;
llist_for_each_entry_safe(ufd, tmp, &bsc_fds, list) {
int flags = 0;
if (FD_ISSET(ufd->fd, &readset)) {
flags |= BSC_FD_READ;
FD_CLR(ufd->fd, &readset);
}
if (FD_ISSET(ufd->fd, &writeset)) {
flags |= BSC_FD_WRITE;
FD_CLR(ufd->fd, &writeset);
}
if (FD_ISSET(ufd->fd, &exceptset)) {
flags |= BSC_FD_EXCEPT;
FD_CLR(ufd->fd, &exceptset);
}
if (flags) {
work = 1;
ufd->cb(ufd, flags);
}
/* ugly, ugly hack. If more than one filedescriptors were
* unregistered, they might have been consecutive and
* llist_for_each_entry_safe() is no longer safe */
/* this seems to happen with the last element of the list as well */
if (unregistered_count >= 1)
goto restart;
}
return work;
}
#endif /* _HAVE_SYS_SELECT_H */
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