--- /dev/null
+/*
+ Unix SMB/CIFS implementation.
+
+ main select loop and event handling - aio/epoll hybrid implementation
+
+ Copyright (C) Andrew Tridgell 2006
+
+ based on events_standard.c
+
+ 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., 675 Mass Ave, Cambridge, MA 02139, USA.
+*/
+/*
+ this is a very strange beast. The Linux AIO implementation doesn't
+ yet integrate properly with epoll, but there is a kernel patch that
+ allows the aio wait primitives to be used to wait for epoll events,
+ and this can be used to give us a unified event system incorporating
+ both aio events and epoll events
+
+ this is _very_ experimental code
+*/
+
+#include "includes.h"
+#include "system/filesys.h"
+#include "system/select.h" /* needed for WITH_EPOLL */
+#include "lib/util/dlinklist.h"
+#include "lib/events/events.h"
+#include "lib/events/events_internal.h"
+#include <libaio.h>
+
+#define MAX_AIO_QUEUE_DEPTH 10
+#define IOCB_CMD_EPOLL_WAIT 9
+
+struct aio_event_context {
+ /* a pointer back to the generic event_context */
+ struct event_context *ev;
+
+ /* number of registered fd event handlers */
+ int num_fd_events;
+
+ /* list of timed events */
+ struct timed_event *timed_events;
+
+ uint32_t destruction_count;
+
+ io_context_t ioctx;
+
+ struct io_event events[MAX_AIO_QUEUE_DEPTH];
+ struct epoll_event epevent;
+
+ struct iocb *epoll_iocb;
+
+ int epoll_fd;
+};
+
+static void aio_event_loop_timer(struct aio_event_context *aio_ev);
+
+/*
+ map from EVENT_FD_* to EPOLLIN/EPOLLOUT
+*/
+static uint32_t epoll_map_flags(uint16_t flags)
+{
+ uint32_t ret = 0;
+ if (flags & EVENT_FD_READ) ret |= (EPOLLIN | EPOLLERR | EPOLLHUP);
+ if (flags & EVENT_FD_WRITE) ret |= (EPOLLOUT | EPOLLERR | EPOLLHUP);
+ return ret;
+}
+
+/*
+ free the epoll fd
+*/
+static int aio_ctx_destructor(struct aio_event_context *aio_ev)
+{
+ close(aio_ev->epoll_fd);
+ aio_ev->epoll_fd = -1;
+ return 0;
+}
+
+#define EPOLL_ADDITIONAL_FD_FLAG_HAS_EVENT (1<<0)
+#define EPOLL_ADDITIONAL_FD_FLAG_REPORT_ERROR (1<<1)
+#define EPOLL_ADDITIONAL_FD_FLAG_GOT_ERROR (1<<2)
+
+/*
+ add the epoll event to the given fd_event
+*/
+static void epoll_add_event(struct aio_event_context *aio_ev, struct fd_event *fde)
+{
+ struct epoll_event event;
+ if (aio_ev->epoll_fd == -1) return;
+
+ fde->additional_flags &= ~EPOLL_ADDITIONAL_FD_FLAG_REPORT_ERROR;
+
+ /* if we don't want events yet, don't add an aio_event */
+ if (fde->flags == 0) return;
+
+ ZERO_STRUCT(event);
+ event.events = epoll_map_flags(fde->flags);
+ event.data.ptr = fde;
+ epoll_ctl(aio_ev->epoll_fd, EPOLL_CTL_ADD, fde->fd, &event);
+ fde->additional_flags |= EPOLL_ADDITIONAL_FD_FLAG_HAS_EVENT;
+
+ /* only if we want to read we want to tell the event handler about errors */
+ if (fde->flags & EVENT_FD_READ) {
+ fde->additional_flags |= EPOLL_ADDITIONAL_FD_FLAG_REPORT_ERROR;
+ }
+}
+
+/*
+ delete the epoll event for given fd_event
+*/
+static void epoll_del_event(struct aio_event_context *aio_ev, struct fd_event *fde)
+{
+ struct epoll_event event;
+ if (aio_ev->epoll_fd == -1) return;
+
+ fde->additional_flags &= ~EPOLL_ADDITIONAL_FD_FLAG_REPORT_ERROR;
+
+ /* if there's no aio_event, we don't need to delete it */
+ if (!(fde->additional_flags & EPOLL_ADDITIONAL_FD_FLAG_HAS_EVENT)) return;
+
+ ZERO_STRUCT(event);
+ event.events = epoll_map_flags(fde->flags);
+ event.data.ptr = fde;
+ epoll_ctl(aio_ev->epoll_fd, EPOLL_CTL_DEL, fde->fd, &event);
+
+ fde->additional_flags &= ~EPOLL_ADDITIONAL_FD_FLAG_HAS_EVENT;
+}
+
+/*
+ change the epoll event to the given fd_event
+*/
+static void epoll_mod_event(struct aio_event_context *aio_ev, struct fd_event *fde)
+{
+ struct epoll_event event;
+ if (aio_ev->epoll_fd == -1) return;
+
+ fde->additional_flags &= ~EPOLL_ADDITIONAL_FD_FLAG_REPORT_ERROR;
+
+ ZERO_STRUCT(event);
+ event.events = epoll_map_flags(fde->flags);
+ event.data.ptr = fde;
+ epoll_ctl(aio_ev->epoll_fd, EPOLL_CTL_MOD, fde->fd, &event);
+
+ /* only if we want to read we want to tell the event handler about errors */
+ if (fde->flags & EVENT_FD_READ) {
+ fde->additional_flags |= EPOLL_ADDITIONAL_FD_FLAG_REPORT_ERROR;
+ }
+}
+
+static void epoll_change_event(struct aio_event_context *aio_ev, struct fd_event *fde)
+{
+ BOOL got_error = (fde->additional_flags & EPOLL_ADDITIONAL_FD_FLAG_GOT_ERROR);
+ BOOL want_read = (fde->flags & EVENT_FD_READ);
+ BOOL want_write= (fde->flags & EVENT_FD_WRITE);
+
+ if (aio_ev->epoll_fd == -1) return;
+
+ fde->additional_flags &= ~EPOLL_ADDITIONAL_FD_FLAG_REPORT_ERROR;
+
+ /* there's already an event */
+ if (fde->additional_flags & EPOLL_ADDITIONAL_FD_FLAG_HAS_EVENT) {
+ if (want_read || (want_write && !got_error)) {
+ epoll_mod_event(aio_ev, fde);
+ return;
+ }
+ epoll_del_event(aio_ev, fde);
+ return;
+ }
+
+ /* there's no aio_event attached to the fde */
+ if (want_read || (want_write && !got_error)) {
+ epoll_add_event(aio_ev, fde);
+ return;
+ }
+}
+
+static int setup_epoll_wait(struct aio_event_context *aio_ev)
+{
+ struct io_event r;
+
+ memset(aio_ev->epoll_iocb, 0, sizeof(*aio_ev->epoll_iocb));
+ aio_ev->epoll_iocb->aio_fildes = aio_ev->epoll_fd;
+ aio_ev->epoll_iocb->aio_lio_opcode = IOCB_CMD_EPOLL_WAIT;
+ aio_ev->epoll_iocb->aio_reqprio = 0;
+
+ aio_ev->epoll_iocb->u.c.nbytes = 1;
+ aio_ev->epoll_iocb->u.c.offset = -1;
+ aio_ev->epoll_iocb->u.c.buf = &aio_ev->epevent;
+
+ if (io_submit(aio_ev->ioctx, 1, &aio_ev->epoll_iocb) != 1) {
+ return -1;
+ }
+}
+
+
+/*
+ event loop handling using aio/epoll hybrid
+*/
+static int aio_event_loop(struct aio_event_context *aio_ev, struct timeval *tvalp)
+{
+ int ret, i;
+ uint32_t destruction_count = aio_ev->destruction_count;
+ struct timespec timeout;
+
+ if (aio_ev->epoll_fd == -1) return -1;
+
+ if (tvalp) {
+ timeout.tv_sec = tvalp->tv_sec;
+ timeout.tv_nsec = tvalp->tv_usec;
+ timeout.tv_nsec *= 1000;
+ }
+
+ setup_epoll_wait(aio_ev);
+
+ ret = io_getevents(aio_ev->ioctx, 1, MAX_AIO_QUEUE_DEPTH,
+ aio_ev->events, tvalp?&timeout:NULL);
+ if (ret == -EINTR) {
+ return 0;
+ }
+
+ if (ret == 0 && tvalp) {
+ aio_event_loop_timer(aio_ev);
+ return 0;
+ }
+
+ for (i=0;i<ret;i++) {
+ struct iocb *finished = aio_ev->events[i].obj;
+ switch (finished->aio_lio_opcode) {
+ case IOCB_CMD_EPOLL_WAIT: {
+ struct epoll_event *ep = (struct epoll_event *)finished->u.c.buf;
+ struct fd_event *fde = talloc_get_type(ep->data.ptr,
+ struct fd_event);
+ uint16_t flags = 0;
+
+ if (fde == NULL) {
+ return -1;
+ }
+ if (ep->events & (EPOLLHUP|EPOLLERR)) {
+ fde->additional_flags |= EPOLL_ADDITIONAL_FD_FLAG_GOT_ERROR;
+ if (!(fde->additional_flags & EPOLL_ADDITIONAL_FD_FLAG_REPORT_ERROR)) {
+ epoll_del_event(aio_ev, fde);
+ continue;
+ }
+ flags |= EVENT_FD_READ;
+ }
+ if (ep->events & EPOLLIN) flags |= EVENT_FD_READ;
+ if (ep->events & EPOLLOUT) flags |= EVENT_FD_WRITE;
+ if (flags) {
+ fde->handler(aio_ev->ev, fde, flags, fde->private_data);
+ if (destruction_count != aio_ev->destruction_count) {
+ return 0;
+ }
+ }
+ break;
+ }
+ }
+ }
+
+ return 0;
+}
+
+/*
+ create a aio_event_context structure.
+*/
+static int aio_event_context_init(struct event_context *ev, void *private_data)
+{
+ struct aio_event_context *aio_ev;
+
+ aio_ev = talloc_zero(ev, struct aio_event_context);
+ if (!aio_ev) return -1;
+
+ aio_ev->ev = ev;
+ aio_ev->epoll_iocb = talloc(aio_ev, struct iocb);
+
+ if (io_queue_init(MAX_AIO_QUEUE_DEPTH, &aio_ev->ioctx) != 0) {
+ return -1;
+ }
+
+ aio_ev->epoll_fd = epoll_create(MAX_AIO_QUEUE_DEPTH);
+ if (aio_ev->epoll_fd == -1) return -1;
+
+ talloc_set_destructor(aio_ev, aio_ctx_destructor);
+
+ ev->additional_data = aio_ev;
+ return 0;
+}
+
+/*
+ destroy an fd_event
+*/
+static int aio_event_fd_destructor(struct fd_event *fde)
+{
+ struct event_context *ev = fde->event_ctx;
+ struct aio_event_context *aio_ev = talloc_get_type(ev->additional_data,
+ struct aio_event_context);
+
+ aio_ev->num_fd_events--;
+ aio_ev->destruction_count++;
+
+ epoll_del_event(aio_ev, fde);
+
+ return 0;
+}
+
+/*
+ add a fd based event
+ return NULL on failure (memory allocation error)
+*/
+static struct fd_event *aio_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 aio_event_context *aio_ev = talloc_get_type(ev->additional_data,
+ struct aio_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;
+
+ aio_ev->num_fd_events++;
+ talloc_set_destructor(fde, aio_event_fd_destructor);
+
+ epoll_add_event(aio_ev, fde);
+
+ return fde;
+}
+
+
+/*
+ return the fd event flags
+*/
+static uint16_t aio_event_get_fd_flags(struct fd_event *fde)
+{
+ return fde->flags;
+}
+
+/*
+ set the fd event flags
+*/
+static void aio_event_set_fd_flags(struct fd_event *fde, uint16_t flags)
+{
+ struct event_context *ev;
+ struct aio_event_context *aio_ev;
+
+ if (fde->flags == flags) return;
+
+ ev = fde->event_ctx;
+ aio_ev = talloc_get_type(ev->additional_data, struct aio_event_context);
+
+ fde->flags = flags;
+
+ epoll_change_event(aio_ev, fde);
+}
+
+/*
+ destroy a timed event
+*/
+static int aio_event_timed_destructor(struct timed_event *te)
+{
+ struct aio_event_context *aio_ev = talloc_get_type(te->event_ctx->additional_data,
+ struct aio_event_context);
+ DLIST_REMOVE(aio_ev->timed_events, te);
+ return 0;
+}
+
+static int aio_event_timed_deny_destructor(struct timed_event *te)
+{
+ return -1;
+}
+
+/*
+ add a timed event
+ return NULL on failure (memory allocation error)
+*/
+static struct timed_event *aio_event_add_timed(struct event_context *ev, TALLOC_CTX *mem_ctx,
+ struct timeval next_event,
+ event_timed_handler_t handler,
+ void *private_data)
+{
+ struct aio_event_context *aio_ev = talloc_get_type(ev->additional_data,
+ struct aio_event_context);
+ struct timed_event *te, *last_te, *cur_te;
+
+ te = talloc(mem_ctx?mem_ctx:ev, struct timed_event);
+ if (te == NULL) return NULL;
+
+ te->event_ctx = ev;
+ te->next_event = next_event;
+ te->handler = handler;
+ te->private_data = private_data;
+ te->additional_data = NULL;
+
+ /* keep the list ordered */
+ last_te = NULL;
+ for (cur_te = aio_ev->timed_events; cur_te; cur_te = cur_te->next) {
+ /* if the new event comes before the current one break */
+ if (!timeval_is_zero(&cur_te->next_event) &&
+ timeval_compare(&te->next_event,
+ &cur_te->next_event) < 0) {
+ break;
+ }
+
+ last_te = cur_te;
+ }
+
+ DLIST_ADD_AFTER(aio_ev->timed_events, te, last_te);
+
+ talloc_set_destructor(te, aio_event_timed_destructor);
+
+ return te;
+}
+
+/*
+ a timer has gone off - call it
+*/
+static void aio_event_loop_timer(struct aio_event_context *aio_ev)
+{
+ struct timeval t = timeval_current();
+ struct timed_event *te = aio_ev->timed_events;
+
+ if (te == NULL) {
+ return;
+ }
+
+ /* deny the handler to free the event */
+ talloc_set_destructor(te, aio_event_timed_deny_destructor);
+
+ /* We need to remove the timer from the list before calling the
+ * handler because in a semi-async inner event loop called from the
+ * handler we don't want to come across this event again -- vl */
+ DLIST_REMOVE(aio_ev->timed_events, te);
+
+ te->handler(aio_ev->ev, te, t, te->private_data);
+
+ /* The destructor isn't necessary anymore, we've already removed the
+ * event from the list. */
+ talloc_set_destructor(te, NULL);
+
+ talloc_free(te);
+}
+
+/*
+ do a single event loop using the events defined in ev
+*/
+static int aio_event_loop_once(struct event_context *ev)
+{
+ struct aio_event_context *aio_ev = talloc_get_type(ev->additional_data,
+ struct aio_event_context);
+ struct timeval tval;
+
+ /* work out the right timeout for all timed events */
+ if (aio_ev->timed_events) {
+ struct timeval t = timeval_current();
+ tval = timeval_until(&t, &aio_ev->timed_events->next_event);
+ if (timeval_is_zero(&tval)) {
+ aio_event_loop_timer(aio_ev);
+ return 0;
+ }
+ } else {
+ /* have a default tick time of 30 seconds. This guarantees
+ that code that uses its own timeout checking will be
+ able to proceeed eventually */
+ tval = timeval_set(30, 0);
+ }
+
+ return aio_event_loop(aio_ev, &tval);
+}
+
+/*
+ return on failure or (with 0) if all fd events are removed
+*/
+static int aio_event_loop_wait(struct event_context *ev)
+{
+ struct aio_event_context *aio_ev = talloc_get_type(ev->additional_data,
+ struct aio_event_context);
+ while (aio_ev->num_fd_events) {
+ if (aio_event_loop_once(ev) != 0) {
+ break;
+ }
+ }
+
+ return 0;
+}
+
+static const struct event_ops aio_event_ops = {
+ .context_init = aio_event_context_init,
+ .add_fd = aio_event_add_fd,
+ .get_fd_flags = aio_event_get_fd_flags,
+ .set_fd_flags = aio_event_set_fd_flags,
+ .add_timed = aio_event_add_timed,
+ .loop_once = aio_event_loop_once,
+ .loop_wait = aio_event_loop_wait,
+};
+
+const struct event_ops *event_aio_get_ops(void)
+{
+ return &aio_event_ops;
+}
git.samba.org / metze / samba / wip.git / commitdiff