diff options
Diffstat (limited to 'src/select.c')
| -rw-r--r-- | src/select.c | 172 |
1 files changed, 172 insertions, 0 deletions
diff --git a/src/select.c b/src/select.c new file mode 100644 index 00000000..6b73377a --- /dev/null +++ b/src/select.c @@ -0,0 +1,172 @@ +/* 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + */ + +#include <fcntl.h> +#include <stdio.h> + +#include <osmocom/core/select.h> +#include <osmocom/core/linuxlist.h> +#include <osmocom/core/timer.h> + +#include "../config.h" + +#ifdef HAVE_SYS_SELECT_H + +/*! \addtogroup select + * @{ + */ + +/*! \file select.c + * \brief select loop abstraction + */ + +static int maxfd = 0; +static LLIST_HEAD(osmo_fds); +static int unregistered_count; + +/*! \brief Register a new file descriptor with select loop abstraction + * \param[in] fd osmocom file descriptor to be registered + */ +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 + struct osmo_fd *entry; + llist_for_each_entry(entry, &osmo_fds, list) { + if (entry == 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) +{ + unregistered_count++; + llist_del(&fd->list); +} + +/*! \brief select main loop integration + * \param[in] polling should we pollonly (1) or block on select (0) + */ +int osmo_select_main(int polling) +{ + struct osmo_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, &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); + } + + osmo_timers_check(); + + 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 */ +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 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 */ |