From 23b61265b85f321ae2ceddc6c75771f8881566d8 Mon Sep 17 00:00:00 2001 From: Simo Sorce Date: Fri, 5 Sep 2008 10:13:10 -0400 Subject: Initial Import --- events/events_select.c | 302 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 302 insertions(+) create mode 100644 events/events_select.c (limited to 'events/events_select.c') diff --git a/events/events_select.c b/events/events_select.c new file mode 100644 index 000000000..54d32204f --- /dev/null +++ b/events/events_select.c @@ -0,0 +1,302 @@ +/* + Unix SMB/CIFS implementation. + main select loop and event handling + Copyright (C) Andrew Tridgell 2003-2005 + Copyright (C) Stefan Metzmacher 2005 + + 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 3 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, see . +*/ + +/* + This is SAMBA's default event loop code + +*/ + +#include "replace.h" +#include "system/filesys.h" +#include "system/select.h" +#include "events.h" +#include "events_util.h" +#include "events_internal.h" + +struct select_event_context { + /* a pointer back to the generic event_context */ + struct event_context *ev; + + /* list of filedescriptor events */ + struct fd_event *fd_events; + + /* list of timed events */ + struct timed_event *timed_events; + + /* the maximum file descriptor number in fd_events */ + int maxfd; + + /* information for exiting from the event loop */ + int exit_code; + + /* this is incremented when the loop over events causes something which + could change the events yet to be processed */ + uint32_t destruction_count; +}; + +/* + create a select_event_context structure. +*/ +static int select_event_context_init(struct event_context *ev) +{ + struct select_event_context *select_ev; + + select_ev = talloc_zero(ev, struct select_event_context); + if (!select_ev) return -1; + select_ev->ev = ev; + + ev->additional_data = select_ev; + return 0; +} + +/* + recalculate the maxfd +*/ +static void calc_maxfd(struct select_event_context *select_ev) +{ + struct fd_event *fde; + + select_ev->maxfd = 0; + for (fde = select_ev->fd_events; fde; fde = fde->next) { + if (fde->fd > select_ev->maxfd) { + select_ev->maxfd = fde->fd; + } + } +} + + +/* to mark the ev->maxfd invalid + * this means we need to recalculate it + */ +#define EVENT_INVALID_MAXFD (-1) + +/* + destroy an fd_event +*/ +static int select_event_fd_destructor(struct fd_event *fde) +{ + struct event_context *ev = fde->event_ctx; + struct select_event_context *select_ev = talloc_get_type(ev->additional_data, + struct select_event_context); + + if (select_ev->maxfd == fde->fd) { + select_ev->maxfd = EVENT_INVALID_MAXFD; + } + + DLIST_REMOVE(select_ev->fd_events, fde); + select_ev->destruction_count++; + + if (fde->flags & EVENT_FD_AUTOCLOSE) { + close(fde->fd); + fde->fd = -1; + } + + return 0; +} + +/* + add a fd based event + return NULL on failure (memory allocation error) +*/ +static struct fd_event *select_event_add_fd(struct event_context *ev, TALLOC_CTX *mem_ctx, + int fd, uint16_t flags, + event_fd_handler_t handler, + void *private_data) +{ + struct select_event_context *select_ev = talloc_get_type(ev->additional_data, + struct select_event_context); + struct fd_event *fde; + + fde = talloc(mem_ctx?mem_ctx:ev, struct fd_event); + if (!fde) return NULL; + + fde->event_ctx = ev; + fde->fd = fd; + fde->flags = flags; + fde->handler = handler; + fde->private_data = private_data; + fde->additional_flags = 0; + fde->additional_data = NULL; + + DLIST_ADD(select_ev->fd_events, fde); + if (fde->fd > select_ev->maxfd) { + select_ev->maxfd = fde->fd; + } + talloc_set_destructor(fde, select_event_fd_destructor); + + return fde; +} + + +/* + return the fd event flags +*/ +static uint16_t select_event_get_fd_flags(struct fd_event *fde) +{ + return fde->flags; +} + +/* + set the fd event flags +*/ +static void select_event_set_fd_flags(struct fd_event *fde, uint16_t flags) +{ + struct event_context *ev; + struct select_event_context *select_ev; + + if (fde->flags == flags) return; + + ev = fde->event_ctx; + select_ev = talloc_get_type(ev->additional_data, struct select_event_context); + + fde->flags = flags; +} + +/* + event loop handling using select() +*/ +static int select_event_loop_select(struct select_event_context *select_ev, struct timeval *tvalp) +{ + fd_set r_fds, w_fds; + struct fd_event *fde; + int selrtn; + uint32_t destruction_count = ++select_ev->destruction_count; + + /* we maybe need to recalculate the maxfd */ + if (select_ev->maxfd == EVENT_INVALID_MAXFD) { + calc_maxfd(select_ev); + } + + FD_ZERO(&r_fds); + FD_ZERO(&w_fds); + + /* setup any fd events */ + for (fde = select_ev->fd_events; fde; fde = fde->next) { + if (fde->flags & EVENT_FD_READ) { + FD_SET(fde->fd, &r_fds); + } + if (fde->flags & EVENT_FD_WRITE) { + FD_SET(fde->fd, &w_fds); + } + } + + if (select_ev->ev->num_signal_handlers && + common_event_check_signal(select_ev->ev)) { + return 0; + } + + selrtn = select(select_ev->maxfd+1, &r_fds, &w_fds, NULL, tvalp); + + if (selrtn == -1 && errno == EINTR && + select_ev->ev->num_signal_handlers) { + common_event_check_signal(select_ev->ev); + return 0; + } + + if (selrtn == -1 && errno == EBADF) { + /* the socket is dead! this should never + happen as the socket should have first been + made readable and that should have removed + the event, so this must be a bug. This is a + fatal error. */ + ev_debug(select_ev->ev, EV_DEBUG_FATAL, + "ERROR: EBADF on select_event_loop_once\n"); + select_ev->exit_code = EBADF; + return -1; + } + + if (selrtn == 0 && tvalp) { + /* we don't care about a possible delay here */ + common_event_loop_timer_delay(select_ev->ev); + return 0; + } + + if (selrtn > 0) { + /* at least one file descriptor is ready - check + which ones and call the handler, being careful to allow + the handler to remove itself when called */ + for (fde = select_ev->fd_events; fde; fde = fde->next) { + uint16_t flags = 0; + + if (FD_ISSET(fde->fd, &r_fds)) flags |= EVENT_FD_READ; + if (FD_ISSET(fde->fd, &w_fds)) flags |= EVENT_FD_WRITE; + if (flags) { + fde->handler(select_ev->ev, fde, flags, fde->private_data); + if (destruction_count != select_ev->destruction_count) { + break; + } + } + } + } + + return 0; +} + +/* + do a single event loop using the events defined in ev +*/ +static int select_event_loop_once(struct event_context *ev) +{ + struct select_event_context *select_ev = talloc_get_type(ev->additional_data, + struct select_event_context); + struct timeval tval; + + tval = common_event_loop_timer_delay(ev); + if (ev_timeval_is_zero(&tval)) { + return 0; + } + + return select_event_loop_select(select_ev, &tval); +} + +/* + return on failure or (with 0) if all fd events are removed +*/ +static int select_event_loop_wait(struct event_context *ev) +{ + struct select_event_context *select_ev = talloc_get_type(ev->additional_data, + struct select_event_context); + select_ev->exit_code = 0; + + while (select_ev->fd_events && select_ev->exit_code == 0) { + if (select_event_loop_once(ev) != 0) { + break; + } + } + + return select_ev->exit_code; +} + +static const struct event_ops select_event_ops = { + .context_init = select_event_context_init, + .add_fd = select_event_add_fd, + .get_fd_flags = select_event_get_fd_flags, + .set_fd_flags = select_event_set_fd_flags, + .add_timed = common_event_add_timed, + .add_signal = common_event_add_signal, + .loop_once = select_event_loop_once, + .loop_wait = select_event_loop_wait, +}; + +bool events_select_init(void) +{ + return event_register_backend("select", &select_event_ops); +} + -- cgit