1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
|
/* 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 as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* 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., 51 Franklin Street, Fifth Floor, Boston,
* MA 02110-1301, USA.
*/
#include <fcntl.h>
#include <stdio.h>
#include <string.h>
#include <stdbool.h>
#include <osmocom/core/select.h>
#include <osmocom/core/linuxlist.h>
#include <osmocom/core/timer.h>
#include "../config.h"
#ifdef HAVE_SYS_SELECT_H
#include <sys/select.h>
/*! \addtogroup select
* @{
* \brief select() loop abstraction
*/
/*! \file select.c */
static int maxfd = 0;
static LLIST_HEAD(osmo_fds);
static int unregistered_count;
/*! \brief Check if a file descriptor is already registered
* \param[in] fd osmocom file descriptor to be checked
* \returns true if registered; otherwise false
*/
bool osmo_fd_is_registered(struct osmo_fd *fd)
{
struct osmo_fd *entry;
llist_for_each_entry(entry, &osmo_fds, list) {
if (entry == fd) {
return true;
}
}
return false;
}
/*! \brief Register a new file descriptor with select loop abstraction
* \param[in] fd osmocom file descriptor to be registered
* \returns 0 on success; negative in case of error
*/
int osmo_fd_register(struct osmo_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;
/* set close-on-exec flag */
flags = fcntl(fd->fd, F_GETFD);
if (flags < 0)
return flags;
flags |= FD_CLOEXEC;
flags = fcntl(fd->fd, F_SETFD, flags);
if (flags < 0)
return flags;
/* Register FD */
if (fd->fd > maxfd)
maxfd = fd->fd;
#ifdef BSC_FD_CHECK
if (osmo_fd_is_registered(fd)) {
fprintf(stderr, "Adding a osmo_fd that is already in the list.\n");
return 0;
}
#endif
llist_add_tail(&fd->list, &osmo_fds);
return 0;
}
/*! \brief Unregister a file descriptor from select loop abstraction
* \param[in] fd osmocom file descriptor to be unregistered
*/
void osmo_fd_unregister(struct osmo_fd *fd)
{
/* Note: when fd is inside the osmo_fds list (not registered before)
* this function will crash! If in doubt, check file descriptor with
* osmo_fd_is_registered() */
unregistered_count++;
llist_del(&fd->list);
}
/*! \brief Populate the fd_sets and return the highest fd number
* \param[in] _rset The readfds to populate
* \param[in] _wset The wrtiefds to populate
* \param[in] _eset The errorfds to populate
*
* \returns The highest file descriptor seen or 0 on an empty list
*/
inline int osmo_fd_fill_fds(void *_rset, void *_wset, void *_eset)
{
fd_set *readset = _rset, *writeset = _wset, *exceptset = _eset;
struct osmo_fd *ufd;
int highfd = 0;
llist_for_each_entry(ufd, &osmo_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);
if (ufd->fd > highfd)
highfd = ufd->fd;
}
return highfd;
}
inline int osmo_fd_disp_fds(void *_rset, void *_wset, void *_eset)
{
struct osmo_fd *ufd, *tmp;
int work = 0;
fd_set *readset = _rset, *writeset = _wset, *exceptset = _eset;
restart:
unregistered_count = 0;
llist_for_each_entry_safe(ufd, tmp, &osmo_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 filedescriptor was
* 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;
}
/*! \brief select main loop integration
* \param[in] polling should we pollonly (1) or block on select (0)
* \returns 0 if no fd handled; 1 if fd handled; negative in case of error
*/
int osmo_select_main(int polling)
{
fd_set readset, writeset, exceptset;
int rc;
struct timeval no_time = {0, 0};
FD_ZERO(&readset);
FD_ZERO(&writeset);
FD_ZERO(&exceptset);
/* prepare read and write fdsets */
osmo_fd_fill_fds(&readset, &writeset, &exceptset);
if (!polling)
osmo_timers_prepare();
rc = select(maxfd+1, &readset, &writeset, &exceptset, polling ? &no_time : osmo_timers_nearest());
if (rc < 0)
return 0;
/* fire timers */
osmo_timers_update();
/* call registered callback functions */
return osmo_fd_disp_fds(&readset, &writeset, &exceptset);
}
/*! \brief find an osmo_fd based on the integer fd
* \param[in] fd file descriptor to use as search key
* \returns \ref osmo_fd for \ref fd; NULL in case it doesn't exist */
struct osmo_fd *osmo_fd_get_by_fd(int fd)
{
struct osmo_fd *ofd;
llist_for_each_entry(ofd, &osmo_fds, list) {
if (ofd->fd == fd)
return ofd;
}
return NULL;
}
/*! @} */
#endif /* _HAVE_SYS_SELECT_H */
|
