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Diffstat (limited to 'tevent/tevent.c')
| -rw-r--r-- | tevent/tevent.c | 310 |
1 files changed, 310 insertions, 0 deletions
diff --git a/tevent/tevent.c b/tevent/tevent.c new file mode 100644 index 000000000..cd470c93a --- /dev/null +++ b/tevent/tevent.c @@ -0,0 +1,310 @@ +/* + Unix SMB/CIFS implementation. + main select loop and event handling + Copyright (C) Andrew Tridgell 2003 + + 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 <http://www.gnu.org/licenses/>. +*/ + +/* + PLEASE READ THIS BEFORE MODIFYING! + + This module is a general abstraction for the main select loop and + event handling. Do not ever put any localised hacks in here, instead + register one of the possible event types and implement that event + somewhere else. + + There are 2 types of event handling that are handled in this module: + + 1) a file descriptor becoming readable or writeable. This is mostly + used for network sockets, but can be used for any type of file + descriptor. You may only register one handler for each file + descriptor/io combination or you will get unpredictable results + (this means that you can have a handler for read events, and a + separate handler for write events, but not two handlers that are + both handling read events) + + 2) a timed event. You can register an event that happens at a + specific time. You can register as many of these as you + like. They are single shot - add a new timed event in the event + handler to get another event. + + To setup a set of events you first need to create a event_context + structure using the function event_context_init(); This returns a + 'struct event_context' that you use in all subsequent calls. + + After that you can add/remove events that you are interested in + using event_add_*() and talloc_free() + + Finally, you call event_loop_wait_once() to block waiting for one of the + events to occor or event_loop_wait() which will loop + forever. + +*/ +#include "replace.h" +#include "tevent.h" +#include "tevent_internal.h" +#include "tevent_util.h" + +struct event_ops_list { + struct event_ops_list *next, *prev; + const char *name; + const struct event_ops *ops; +}; + +/* list of registered event backends */ +static struct event_ops_list *event_backends = NULL; +static char *event_default_backend = NULL; + +/* + register an events backend +*/ +bool event_register_backend(const char *name, const struct event_ops *ops) +{ + struct event_ops_list *e; + + for (e = event_backends; e != NULL; e = e->next) { + if (0 == strcmp(e->name, name)) { + /* already registered, skip it */ + return true; + } + } + + e = talloc(talloc_autofree_context(), struct event_ops_list); + if (e == NULL) return false; + + e->name = name; + e->ops = ops; + DLIST_ADD(event_backends, e); + + return true; +} + +/* + set the default event backend + */ +void event_set_default_backend(const char *backend) +{ + if (event_default_backend) free(event_default_backend); + event_default_backend = strdup(backend); +} + +/* + initialise backends if not already done +*/ +static void event_backend_init(void) +{ + events_select_init(); + events_standard_init(); +#if HAVE_EVENTS_EPOLL + events_epoll_init(); +#endif +#if HAVE_LINUX_AIO + events_aio_init(); +#endif +} + +/* + list available backends +*/ +const char **event_backend_list(TALLOC_CTX *mem_ctx) +{ + const char **list = NULL; + struct event_ops_list *e; + + event_backend_init(); + + for (e=event_backends;e;e=e->next) { + list = ev_str_list_add(list, e->name); + } + + talloc_steal(mem_ctx, list); + + return list; +} + +/* + create a event_context structure for a specific implemementation. + This must be the first events call, and all subsequent calls pass + this event_context as the first element. Event handlers also + receive this as their first argument. + + This function is for allowing third-party-applications to hook in gluecode + to their own event loop code, so that they can make async usage of our client libs + + NOTE: use event_context_init() inside of samba! +*/ +static struct event_context *event_context_init_ops(TALLOC_CTX *mem_ctx, + const struct event_ops *ops) +{ + struct event_context *ev; + int ret; + + ev = talloc_zero(mem_ctx, struct event_context); + if (!ev) return NULL; + + ev->ops = ops; + + ret = ev->ops->context_init(ev); + if (ret != 0) { + talloc_free(ev); + return NULL; + } + + return ev; +} + +/* + create a event_context structure. This must be the first events + call, and all subsequent calls pass this event_context as the first + element. Event handlers also receive this as their first argument. +*/ +struct event_context *event_context_init_byname(TALLOC_CTX *mem_ctx, const char *name) +{ + struct event_ops_list *e; + + event_backend_init(); + + if (name == NULL) { + name = event_default_backend; + } + if (name == NULL) { + name = "standard"; + } + + for (e=event_backends;e;e=e->next) { + if (strcmp(name, e->name) == 0) { + return event_context_init_ops(mem_ctx, e->ops); + } + } + return NULL; +} + + +/* + create a event_context structure. This must be the first events + call, and all subsequent calls pass this event_context as the first + element. Event handlers also receive this as their first argument. +*/ +struct event_context *event_context_init(TALLOC_CTX *mem_ctx) +{ + return event_context_init_byname(mem_ctx, NULL); +} + +/* + add a fd based event + return NULL on failure (memory allocation error) + + if flags contains EVENT_FD_AUTOCLOSE then the fd will be closed when + the returned fd_event context is freed +*/ +struct fd_event *event_add_fd(struct event_context *ev, TALLOC_CTX *mem_ctx, + int fd, uint16_t flags, event_fd_handler_t handler, + void *private_data) +{ + return ev->ops->add_fd(ev, mem_ctx, fd, flags, handler, private_data); +} + +/* + add a disk aio event +*/ +struct aio_event *event_add_aio(struct event_context *ev, + TALLOC_CTX *mem_ctx, + struct iocb *iocb, + event_aio_handler_t handler, + void *private_data) +{ + if (ev->ops->add_aio == NULL) return NULL; + return ev->ops->add_aio(ev, mem_ctx, iocb, handler, private_data); +} + +/* + return the fd event flags +*/ +uint16_t event_get_fd_flags(struct fd_event *fde) +{ + if (!fde) return 0; + return fde->event_ctx->ops->get_fd_flags(fde); +} + +/* + set the fd event flags +*/ +void event_set_fd_flags(struct fd_event *fde, uint16_t flags) +{ + if (!fde) return; + fde->event_ctx->ops->set_fd_flags(fde, flags); +} + +/* + add a timed event + return NULL on failure +*/ +struct timed_event *event_add_timed(struct event_context *ev, TALLOC_CTX *mem_ctx, + struct timeval next_event, + event_timed_handler_t handler, + void *private_data) +{ + return ev->ops->add_timed(ev, mem_ctx, next_event, handler, private_data); +} + +/* + add a signal event + + sa_flags are flags to sigaction(2) + + return NULL on failure +*/ +struct signal_event *event_add_signal(struct event_context *ev, TALLOC_CTX *mem_ctx, + int signum, + int sa_flags, + event_signal_handler_t handler, + void *private_data) +{ + return ev->ops->add_signal(ev, mem_ctx, signum, sa_flags, handler, private_data); +} + +/* + do a single event loop using the events defined in ev +*/ +int event_loop_once(struct event_context *ev) +{ + return ev->ops->loop_once(ev); +} + +/* + return on failure or (with 0) if all fd events are removed +*/ +int event_loop_wait(struct event_context *ev) +{ + return ev->ops->loop_wait(ev); +} + +/* + find an event context that is a parent of the given memory context, + or create a new event context as a child of the given context if + none is found + + This should be used in preference to event_context_init() in places + where you would prefer to use the existing event context if possible + (which is most situations) +*/ +struct event_context *event_context_find(TALLOC_CTX *mem_ctx) +{ + struct event_context *ev = talloc_find_parent_bytype(mem_ctx, struct event_context); + if (ev == NULL) { + ev = event_context_init(mem_ctx); + } + return ev; +} |