blob: 7f45426d08403f7f2aa256ccadccb34ed98b4a34 [file] [log] [blame]
Harald Welte59b04682009-06-10 05:40:52 +08001/* select filedescriptor handling, taken from:
2 * userspace logging daemon for the iptables ULOG target
3 * of the linux 2.4 netfilter subsystem.
4 *
5 * (C) 2000-2009 by Harald Welte <laforge@gnumonks.org>
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2
9 * as published by the Free Software Foundation
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
19 */
20
21#include <fcntl.h>
22#include <openbsc/select.h>
23#include <openbsc/linuxlist.h>
24#include <openbsc/timer.h>
25
26static int maxfd = 0;
27static LLIST_HEAD(bsc_fds);
Harald Welteb01974f2009-07-28 13:32:00 +020028static int unregistered_count;
Harald Welte59b04682009-06-10 05:40:52 +080029
30int bsc_register_fd(struct bsc_fd *fd)
31{
32 int flags;
33
34 /* make FD nonblocking */
35 flags = fcntl(fd->fd, F_GETFL);
36 if (flags < 0)
37 return flags;
38 flags |= O_NONBLOCK;
39 flags = fcntl(fd->fd, F_SETFL, flags);
40 if (flags < 0)
41 return flags;
42
43 /* Register FD */
44 if (fd->fd > maxfd)
45 maxfd = fd->fd;
46
47 llist_add_tail(&fd->list, &bsc_fds);
48
49 return 0;
50}
51
52void bsc_unregister_fd(struct bsc_fd *fd)
53{
Harald Welteb01974f2009-07-28 13:32:00 +020054 unregistered_count++;
Harald Welte59b04682009-06-10 05:40:52 +080055 llist_del(&fd->list);
56}
57
58int bsc_select_main(int polling)
59{
60 struct bsc_fd *ufd, *tmp;
61 fd_set readset, writeset, exceptset;
62 int work = 0, rc;
63 struct timeval no_time = {0, 0};
64
65 FD_ZERO(&readset);
66 FD_ZERO(&writeset);
67 FD_ZERO(&exceptset);
68
69 /* prepare read and write fdsets */
70 llist_for_each_entry(ufd, &bsc_fds, list) {
71 if (ufd->when & BSC_FD_READ)
72 FD_SET(ufd->fd, &readset);
73
74 if (ufd->when & BSC_FD_WRITE)
75 FD_SET(ufd->fd, &writeset);
76
77 if (ufd->when & BSC_FD_EXCEPT)
78 FD_SET(ufd->fd, &exceptset);
79 }
80
81 if (!polling)
82 bsc_prepare_timers();
83 rc = select(maxfd+1, &readset, &writeset, &exceptset, polling ? &no_time : bsc_nearest_timer());
84 if (rc < 0)
85 return 0;
86
87 /* fire timers */
88 bsc_update_timers();
89
90 /* call registered callback functions */
Harald Welteb01974f2009-07-28 13:32:00 +020091restart:
92 unregistered_count = 0;
Harald Welte59b04682009-06-10 05:40:52 +080093 llist_for_each_entry_safe(ufd, tmp, &bsc_fds, list) {
94 int flags = 0;
95
96 if (FD_ISSET(ufd->fd, &readset))
97 flags |= BSC_FD_READ;
98
99 if (FD_ISSET(ufd->fd, &writeset))
100 flags |= BSC_FD_WRITE;
101
102 if (FD_ISSET(ufd->fd, &exceptset))
103 flags |= BSC_FD_EXCEPT;
104
105 if (flags) {
106 work = 1;
107 ufd->cb(ufd, flags);
108 }
Harald Welteb01974f2009-07-28 13:32:00 +0200109 /* ugly, ugly hack. If more than one filedescriptors were
110 * unregistered, they might have been consecutive and
111 * llist_for_each_entry_safe() is no longer safe */
112 if (unregistered_count > 1)
113 goto restart;
Harald Welte59b04682009-06-10 05:40:52 +0800114 }
115 return work;
116}