Neels Hofmeyr | 17518fe | 2017-06-20 04:35:06 +0200 | [diff] [blame] | 1 | /*! \file select.c |
| 2 | * select filedescriptor handling. |
| 3 | * Taken from: |
Harald Welte | ec8b450 | 2010-02-20 20:34:29 +0100 | [diff] [blame] | 4 | * userspace logging daemon for the iptables ULOG target |
Neels Hofmeyr | 17518fe | 2017-06-20 04:35:06 +0200 | [diff] [blame] | 5 | * of the linux 2.4 netfilter subsystem. */ |
| 6 | /* |
Harald Welte | ec8b450 | 2010-02-20 20:34:29 +0100 | [diff] [blame] | 7 | * (C) 2000-2009 by Harald Welte <laforge@gnumonks.org> |
Harald Welte | e08da97 | 2017-11-13 01:00:26 +0900 | [diff] [blame] | 8 | * All Rights Reserverd. |
| 9 | * |
| 10 | * SPDX-License-Identifier: GPL-2.0+ |
Harald Welte | ec8b450 | 2010-02-20 20:34:29 +0100 | [diff] [blame] | 11 | * |
| 12 | * This program is free software; you can redistribute it and/or modify |
Harald Welte | 9d92f0e | 2010-10-31 13:56:45 +0100 | [diff] [blame] | 13 | * it under the terms of the GNU General Public License as published by |
| 14 | * the Free Software Foundation; either version 2 of the License, or |
| 15 | * (at your option) any later version. |
Harald Welte | ec8b450 | 2010-02-20 20:34:29 +0100 | [diff] [blame] | 16 | * |
| 17 | * This program is distributed in the hope that it will be useful, |
| 18 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 19 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 20 | * GNU General Public License for more details. |
| 21 | * |
| 22 | * You should have received a copy of the GNU General Public License |
| 23 | * along with this program; if not, write to the Free Software |
Jaroslav Škarvada | 2b82c1c | 2015-11-11 16:02:54 +0100 | [diff] [blame] | 24 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, |
| 25 | * MA 02110-1301, USA. |
Harald Welte | ec8b450 | 2010-02-20 20:34:29 +0100 | [diff] [blame] | 26 | */ |
| 27 | |
| 28 | #include <fcntl.h> |
Holger Hans Peter Freyther | 4355831 | 2010-08-06 06:48:43 +0800 | [diff] [blame] | 29 | #include <stdio.h> |
Harald Welte | ea91a51 | 2017-07-13 14:28:30 +0200 | [diff] [blame] | 30 | #include <unistd.h> |
Harald Welte | 9e166e8 | 2014-03-10 17:28:33 +0100 | [diff] [blame] | 31 | #include <string.h> |
Philipp Maier | b288853 | 2016-12-09 14:07:18 +0100 | [diff] [blame] | 32 | #include <stdbool.h> |
Holger Hans Peter Freyther | 4355831 | 2010-08-06 06:48:43 +0800 | [diff] [blame] | 33 | |
Pablo Neira Ayuso | 8341934 | 2011-03-22 16:36:13 +0100 | [diff] [blame] | 34 | #include <osmocom/core/select.h> |
| 35 | #include <osmocom/core/linuxlist.h> |
| 36 | #include <osmocom/core/timer.h> |
Harald Welte | ec8b450 | 2010-02-20 20:34:29 +0100 | [diff] [blame] | 37 | |
Harald Welte | 5484480 | 2010-02-20 22:23:08 +0100 | [diff] [blame] | 38 | #include "../config.h" |
| 39 | |
Harald Welte | ec8b450 | 2010-02-20 20:34:29 +0100 | [diff] [blame] | 40 | #ifdef HAVE_SYS_SELECT_H |
Harald Welte | 1d604d8 | 2017-05-17 15:32:35 +0100 | [diff] [blame] | 41 | #include <sys/select.h> |
Harald Welte | ec8b450 | 2010-02-20 20:34:29 +0100 | [diff] [blame] | 42 | |
Harald Welte | ba6988b | 2011-08-17 12:46:48 +0200 | [diff] [blame] | 43 | /*! \addtogroup select |
| 44 | * @{ |
Neels Hofmeyr | 87e4550 | 2017-06-20 00:17:59 +0200 | [diff] [blame] | 45 | * select() loop abstraction |
Neels Hofmeyr | 17518fe | 2017-06-20 04:35:06 +0200 | [diff] [blame] | 46 | * |
| 47 | * \file select.c */ |
Harald Welte | ba6988b | 2011-08-17 12:46:48 +0200 | [diff] [blame] | 48 | |
Harald Welte | ec8b450 | 2010-02-20 20:34:29 +0100 | [diff] [blame] | 49 | static int maxfd = 0; |
Pablo Neira Ayuso | f7f89d0 | 2011-05-07 12:42:40 +0200 | [diff] [blame] | 50 | static LLIST_HEAD(osmo_fds); |
Harald Welte | ec8b450 | 2010-02-20 20:34:29 +0100 | [diff] [blame] | 51 | static int unregistered_count; |
| 52 | |
Harald Welte | 6c0a0e6 | 2017-08-12 11:43:14 +0200 | [diff] [blame] | 53 | /*! Set up an osmo-fd. Will not register it. |
| 54 | * \param[inout] ofd Osmo FD to be set-up |
| 55 | * \param[in] fd OS-level file descriptor number |
| 56 | * \param[in] when bit-mask of BSC_FD_{READ,WRITE,EXECEPT} |
| 57 | * \param[in] cb Call-back function to be called |
| 58 | * \param[in] data Private context pointer |
| 59 | * \param[in] priv_nr Private number |
| 60 | */ |
| 61 | void osmo_fd_setup(struct osmo_fd *ofd, int fd, unsigned int when, |
| 62 | int (*cb)(struct osmo_fd *fd, unsigned int what), |
| 63 | void *data, unsigned int priv_nr) |
| 64 | { |
| 65 | ofd->fd = fd; |
| 66 | ofd->when = when; |
| 67 | ofd->cb = cb; |
| 68 | ofd->data = data; |
| 69 | ofd->priv_nr = priv_nr; |
| 70 | } |
Philipp Maier | b288853 | 2016-12-09 14:07:18 +0100 | [diff] [blame] | 71 | |
Neels Hofmeyr | 87e4550 | 2017-06-20 00:17:59 +0200 | [diff] [blame] | 72 | /*! Check if a file descriptor is already registered |
Philipp Maier | b288853 | 2016-12-09 14:07:18 +0100 | [diff] [blame] | 73 | * \param[in] fd osmocom file descriptor to be checked |
| 74 | * \returns true if registered; otherwise false |
| 75 | */ |
| 76 | bool osmo_fd_is_registered(struct osmo_fd *fd) |
| 77 | { |
| 78 | struct osmo_fd *entry; |
| 79 | llist_for_each_entry(entry, &osmo_fds, list) { |
| 80 | if (entry == fd) { |
| 81 | return true; |
| 82 | } |
| 83 | } |
| 84 | |
| 85 | return false; |
| 86 | } |
| 87 | |
Neels Hofmeyr | 87e4550 | 2017-06-20 00:17:59 +0200 | [diff] [blame] | 88 | /*! Register a new file descriptor with select loop abstraction |
Harald Welte | ba6988b | 2011-08-17 12:46:48 +0200 | [diff] [blame] | 89 | * \param[in] fd osmocom file descriptor to be registered |
Harald Welte | 2d2e2cc | 2016-04-25 12:11:20 +0200 | [diff] [blame] | 90 | * \returns 0 on success; negative in case of error |
Harald Welte | ba6988b | 2011-08-17 12:46:48 +0200 | [diff] [blame] | 91 | */ |
Pablo Neira Ayuso | f7f89d0 | 2011-05-07 12:42:40 +0200 | [diff] [blame] | 92 | int osmo_fd_register(struct osmo_fd *fd) |
Harald Welte | ec8b450 | 2010-02-20 20:34:29 +0100 | [diff] [blame] | 93 | { |
| 94 | int flags; |
| 95 | |
| 96 | /* make FD nonblocking */ |
| 97 | flags = fcntl(fd->fd, F_GETFL); |
| 98 | if (flags < 0) |
| 99 | return flags; |
| 100 | flags |= O_NONBLOCK; |
| 101 | flags = fcntl(fd->fd, F_SETFL, flags); |
| 102 | if (flags < 0) |
| 103 | return flags; |
| 104 | |
Harald Welte | 32e1f23 | 2011-06-26 13:07:18 +0200 | [diff] [blame] | 105 | /* set close-on-exec flag */ |
| 106 | flags = fcntl(fd->fd, F_GETFD); |
| 107 | if (flags < 0) |
| 108 | return flags; |
| 109 | flags |= FD_CLOEXEC; |
| 110 | flags = fcntl(fd->fd, F_SETFD, flags); |
| 111 | if (flags < 0) |
| 112 | return flags; |
| 113 | |
Harald Welte | ec8b450 | 2010-02-20 20:34:29 +0100 | [diff] [blame] | 114 | /* Register FD */ |
| 115 | if (fd->fd > maxfd) |
| 116 | maxfd = fd->fd; |
| 117 | |
Holger Hans Peter Freyther | 4355831 | 2010-08-06 06:48:43 +0800 | [diff] [blame] | 118 | #ifdef BSC_FD_CHECK |
Philipp Maier | b288853 | 2016-12-09 14:07:18 +0100 | [diff] [blame] | 119 | if (osmo_fd_is_registered(fd)) { |
| 120 | fprintf(stderr, "Adding a osmo_fd that is already in the list.\n"); |
| 121 | return 0; |
Holger Hans Peter Freyther | 4355831 | 2010-08-06 06:48:43 +0800 | [diff] [blame] | 122 | } |
| 123 | #endif |
| 124 | |
Pablo Neira Ayuso | f7f89d0 | 2011-05-07 12:42:40 +0200 | [diff] [blame] | 125 | llist_add_tail(&fd->list, &osmo_fds); |
Harald Welte | ec8b450 | 2010-02-20 20:34:29 +0100 | [diff] [blame] | 126 | |
| 127 | return 0; |
| 128 | } |
| 129 | |
Neels Hofmeyr | 87e4550 | 2017-06-20 00:17:59 +0200 | [diff] [blame] | 130 | /*! Unregister a file descriptor from select loop abstraction |
Harald Welte | ba6988b | 2011-08-17 12:46:48 +0200 | [diff] [blame] | 131 | * \param[in] fd osmocom file descriptor to be unregistered |
| 132 | */ |
Pablo Neira Ayuso | f7f89d0 | 2011-05-07 12:42:40 +0200 | [diff] [blame] | 133 | void osmo_fd_unregister(struct osmo_fd *fd) |
Harald Welte | ec8b450 | 2010-02-20 20:34:29 +0100 | [diff] [blame] | 134 | { |
Philipp Maier | b288853 | 2016-12-09 14:07:18 +0100 | [diff] [blame] | 135 | /* Note: when fd is inside the osmo_fds list (not registered before) |
| 136 | * this function will crash! If in doubt, check file descriptor with |
| 137 | * osmo_fd_is_registered() */ |
Harald Welte | ec8b450 | 2010-02-20 20:34:29 +0100 | [diff] [blame] | 138 | unregistered_count++; |
| 139 | llist_del(&fd->list); |
| 140 | } |
| 141 | |
Harald Welte | ea91a51 | 2017-07-13 14:28:30 +0200 | [diff] [blame] | 142 | /*! Close a file descriptor, mark it as closed + unregister from select loop abstraction |
| 143 | * \param[in] fd osmocom file descriptor to be unregistered + closed |
| 144 | * |
| 145 | * If \a fd is registered, we unregister it from the select() loop |
| 146 | * abstraction. We then close the fd and set it to -1, as well as |
| 147 | * unsetting any 'when' flags */ |
| 148 | void osmo_fd_close(struct osmo_fd *fd) |
| 149 | { |
| 150 | if (osmo_fd_is_registered(fd)) |
| 151 | osmo_fd_unregister(fd); |
| 152 | if (fd->fd != -1) |
| 153 | close(fd->fd); |
| 154 | fd->fd = -1; |
| 155 | fd->when = 0; |
| 156 | } |
| 157 | |
Neels Hofmeyr | 87e4550 | 2017-06-20 00:17:59 +0200 | [diff] [blame] | 158 | /*! Populate the fd_sets and return the highest fd number |
Holger Hans Peter Freyther | ff20641 | 2017-03-07 14:28:38 +0100 | [diff] [blame] | 159 | * \param[in] _rset The readfds to populate |
| 160 | * \param[in] _wset The wrtiefds to populate |
| 161 | * \param[in] _eset The errorfds to populate |
| 162 | * |
| 163 | * \returns The highest file descriptor seen or 0 on an empty list |
| 164 | */ |
Holger Hans Peter Freyther | 61f2888 | 2016-03-21 09:55:05 +0100 | [diff] [blame] | 165 | inline int osmo_fd_fill_fds(void *_rset, void *_wset, void *_eset) |
Harald Welte | ec8b450 | 2010-02-20 20:34:29 +0100 | [diff] [blame] | 166 | { |
Holger Hans Peter Freyther | 61f2888 | 2016-03-21 09:55:05 +0100 | [diff] [blame] | 167 | fd_set *readset = _rset, *writeset = _wset, *exceptset = _eset; |
| 168 | struct osmo_fd *ufd; |
Holger Hans Peter Freyther | ff20641 | 2017-03-07 14:28:38 +0100 | [diff] [blame] | 169 | int highfd = 0; |
Harald Welte | ec8b450 | 2010-02-20 20:34:29 +0100 | [diff] [blame] | 170 | |
Pablo Neira Ayuso | f7f89d0 | 2011-05-07 12:42:40 +0200 | [diff] [blame] | 171 | llist_for_each_entry(ufd, &osmo_fds, list) { |
Harald Welte | ec8b450 | 2010-02-20 20:34:29 +0100 | [diff] [blame] | 172 | if (ufd->when & BSC_FD_READ) |
Holger Hans Peter Freyther | 61f2888 | 2016-03-21 09:55:05 +0100 | [diff] [blame] | 173 | FD_SET(ufd->fd, readset); |
Harald Welte | ec8b450 | 2010-02-20 20:34:29 +0100 | [diff] [blame] | 174 | |
| 175 | if (ufd->when & BSC_FD_WRITE) |
Holger Hans Peter Freyther | 61f2888 | 2016-03-21 09:55:05 +0100 | [diff] [blame] | 176 | FD_SET(ufd->fd, writeset); |
Harald Welte | ec8b450 | 2010-02-20 20:34:29 +0100 | [diff] [blame] | 177 | |
| 178 | if (ufd->when & BSC_FD_EXCEPT) |
Holger Hans Peter Freyther | 61f2888 | 2016-03-21 09:55:05 +0100 | [diff] [blame] | 179 | FD_SET(ufd->fd, exceptset); |
Holger Hans Peter Freyther | ff20641 | 2017-03-07 14:28:38 +0100 | [diff] [blame] | 180 | |
| 181 | if (ufd->fd > highfd) |
| 182 | highfd = ufd->fd; |
Harald Welte | ec8b450 | 2010-02-20 20:34:29 +0100 | [diff] [blame] | 183 | } |
| 184 | |
Holger Hans Peter Freyther | ff20641 | 2017-03-07 14:28:38 +0100 | [diff] [blame] | 185 | return highfd; |
Holger Hans Peter Freyther | 61f2888 | 2016-03-21 09:55:05 +0100 | [diff] [blame] | 186 | } |
Harald Welte | ec8b450 | 2010-02-20 20:34:29 +0100 | [diff] [blame] | 187 | |
Holger Hans Peter Freyther | 61f2888 | 2016-03-21 09:55:05 +0100 | [diff] [blame] | 188 | inline int osmo_fd_disp_fds(void *_rset, void *_wset, void *_eset) |
| 189 | { |
| 190 | struct osmo_fd *ufd, *tmp; |
| 191 | int work = 0; |
| 192 | fd_set *readset = _rset, *writeset = _wset, *exceptset = _eset; |
Harald Welte | ec8b450 | 2010-02-20 20:34:29 +0100 | [diff] [blame] | 193 | |
Harald Welte | ec8b450 | 2010-02-20 20:34:29 +0100 | [diff] [blame] | 194 | restart: |
| 195 | unregistered_count = 0; |
Pablo Neira Ayuso | f7f89d0 | 2011-05-07 12:42:40 +0200 | [diff] [blame] | 196 | llist_for_each_entry_safe(ufd, tmp, &osmo_fds, list) { |
Harald Welte | ec8b450 | 2010-02-20 20:34:29 +0100 | [diff] [blame] | 197 | int flags = 0; |
| 198 | |
Holger Hans Peter Freyther | 61f2888 | 2016-03-21 09:55:05 +0100 | [diff] [blame] | 199 | if (FD_ISSET(ufd->fd, readset)) { |
Harald Welte | ec8b450 | 2010-02-20 20:34:29 +0100 | [diff] [blame] | 200 | flags |= BSC_FD_READ; |
Holger Hans Peter Freyther | 61f2888 | 2016-03-21 09:55:05 +0100 | [diff] [blame] | 201 | FD_CLR(ufd->fd, readset); |
Harald Welte | ec8b450 | 2010-02-20 20:34:29 +0100 | [diff] [blame] | 202 | } |
| 203 | |
Holger Hans Peter Freyther | 61f2888 | 2016-03-21 09:55:05 +0100 | [diff] [blame] | 204 | if (FD_ISSET(ufd->fd, writeset)) { |
Harald Welte | ec8b450 | 2010-02-20 20:34:29 +0100 | [diff] [blame] | 205 | flags |= BSC_FD_WRITE; |
Holger Hans Peter Freyther | 61f2888 | 2016-03-21 09:55:05 +0100 | [diff] [blame] | 206 | FD_CLR(ufd->fd, writeset); |
Harald Welte | ec8b450 | 2010-02-20 20:34:29 +0100 | [diff] [blame] | 207 | } |
| 208 | |
Holger Hans Peter Freyther | 61f2888 | 2016-03-21 09:55:05 +0100 | [diff] [blame] | 209 | if (FD_ISSET(ufd->fd, exceptset)) { |
Harald Welte | ec8b450 | 2010-02-20 20:34:29 +0100 | [diff] [blame] | 210 | flags |= BSC_FD_EXCEPT; |
Holger Hans Peter Freyther | 61f2888 | 2016-03-21 09:55:05 +0100 | [diff] [blame] | 211 | FD_CLR(ufd->fd, exceptset); |
Harald Welte | ec8b450 | 2010-02-20 20:34:29 +0100 | [diff] [blame] | 212 | } |
| 213 | |
| 214 | if (flags) { |
| 215 | work = 1; |
| 216 | ufd->cb(ufd, flags); |
| 217 | } |
Holger Hans Peter Freyther | 92e1e70 | 2014-04-09 17:24:00 +0200 | [diff] [blame] | 218 | /* ugly, ugly hack. If more than one filedescriptor was |
Harald Welte | ec8b450 | 2010-02-20 20:34:29 +0100 | [diff] [blame] | 219 | * unregistered, they might have been consecutive and |
| 220 | * llist_for_each_entry_safe() is no longer safe */ |
Holger Hans Peter Freyther | 23ba474 | 2010-04-11 17:33:19 +0200 | [diff] [blame] | 221 | /* this seems to happen with the last element of the list as well */ |
| 222 | if (unregistered_count >= 1) |
Harald Welte | ec8b450 | 2010-02-20 20:34:29 +0100 | [diff] [blame] | 223 | goto restart; |
| 224 | } |
Holger Hans Peter Freyther | 61f2888 | 2016-03-21 09:55:05 +0100 | [diff] [blame] | 225 | |
Harald Welte | ec8b450 | 2010-02-20 20:34:29 +0100 | [diff] [blame] | 226 | return work; |
| 227 | } |
| 228 | |
Neels Hofmeyr | 87e4550 | 2017-06-20 00:17:59 +0200 | [diff] [blame] | 229 | /*! select main loop integration |
Holger Hans Peter Freyther | 61f2888 | 2016-03-21 09:55:05 +0100 | [diff] [blame] | 230 | * \param[in] polling should we pollonly (1) or block on select (0) |
Harald Welte | 2d2e2cc | 2016-04-25 12:11:20 +0200 | [diff] [blame] | 231 | * \returns 0 if no fd handled; 1 if fd handled; negative in case of error |
Holger Hans Peter Freyther | 61f2888 | 2016-03-21 09:55:05 +0100 | [diff] [blame] | 232 | */ |
| 233 | int osmo_select_main(int polling) |
| 234 | { |
| 235 | fd_set readset, writeset, exceptset; |
| 236 | int rc; |
| 237 | struct timeval no_time = {0, 0}; |
| 238 | |
| 239 | FD_ZERO(&readset); |
| 240 | FD_ZERO(&writeset); |
| 241 | FD_ZERO(&exceptset); |
| 242 | |
| 243 | /* prepare read and write fdsets */ |
| 244 | osmo_fd_fill_fds(&readset, &writeset, &exceptset); |
| 245 | |
Holger Hans Peter Freyther | 61f2888 | 2016-03-21 09:55:05 +0100 | [diff] [blame] | 246 | if (!polling) |
| 247 | osmo_timers_prepare(); |
| 248 | rc = select(maxfd+1, &readset, &writeset, &exceptset, polling ? &no_time : osmo_timers_nearest()); |
| 249 | if (rc < 0) |
| 250 | return 0; |
| 251 | |
| 252 | /* fire timers */ |
| 253 | osmo_timers_update(); |
| 254 | |
| 255 | /* call registered callback functions */ |
| 256 | return osmo_fd_disp_fds(&readset, &writeset, &exceptset); |
| 257 | } |
| 258 | |
Neels Hofmeyr | 87e4550 | 2017-06-20 00:17:59 +0200 | [diff] [blame] | 259 | /*! find an osmo_fd based on the integer fd |
Harald Welte | 2d2e2cc | 2016-04-25 12:11:20 +0200 | [diff] [blame] | 260 | * \param[in] fd file descriptor to use as search key |
| 261 | * \returns \ref osmo_fd for \ref fd; NULL in case it doesn't exist */ |
Harald Welte | 6c33ae2 | 2016-03-19 21:17:58 +0100 | [diff] [blame] | 262 | struct osmo_fd *osmo_fd_get_by_fd(int fd) |
| 263 | { |
| 264 | struct osmo_fd *ofd; |
| 265 | |
| 266 | llist_for_each_entry(ofd, &osmo_fds, list) { |
| 267 | if (ofd->fd == fd) |
| 268 | return ofd; |
| 269 | } |
| 270 | return NULL; |
| 271 | } |
| 272 | |
Sylvain Munaut | dca7d2c | 2012-04-18 21:53:23 +0200 | [diff] [blame] | 273 | /*! @} */ |
Harald Welte | ba6988b | 2011-08-17 12:46:48 +0200 | [diff] [blame] | 274 | |
Harald Welte | ec8b450 | 2010-02-20 20:34:29 +0100 | [diff] [blame] | 275 | #endif /* _HAVE_SYS_SELECT_H */ |