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-rw-r--r--lib/tevent/tevent_aio.c567
1 files changed, 567 insertions, 0 deletions
diff --git a/lib/tevent/tevent_aio.c b/lib/tevent/tevent_aio.c
new file mode 100644
index 0000000000..7c3473b9a7
--- /dev/null
+++ b/lib/tevent/tevent_aio.c
@@ -0,0 +1,567 @@
+/*
+ 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 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/>.
+*/
+/*
+ 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 "system/filesys.h"
+#include "replace.h"
+#include "tevent.h"
+#include "tevent_internal.h"
+#include "tevent_util.h"
+#include <sys/epoll.h>
+#include <libaio.h>
+
+#define MAX_AIO_QUEUE_DEPTH 100
+#ifndef IOCB_CMD_EPOLL_WAIT
+#define IOCB_CMD_EPOLL_WAIT 9
+#endif
+
+struct aio_event_context {
+ /* a pointer back to the generic event_context */
+ struct event_context *ev;
+
+ /* list of filedescriptor events */
+ struct fd_event *fd_events;
+
+ /* number of registered fd event handlers */
+ int num_fd_events;
+
+ uint32_t destruction_count;
+
+ io_context_t ioctx;
+
+ struct epoll_event epevent[MAX_AIO_QUEUE_DEPTH];
+
+ struct iocb *epoll_iocb;
+
+ int epoll_fd;
+ int is_epoll_set;
+ pid_t pid;
+};
+
+struct aio_event {
+ struct event_context *event_ctx;
+ struct iocb iocb;
+ void *private_data;
+ event_aio_handler_t handler;
+};
+
+/*
+ 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)
+{
+ io_queue_release(aio_ev->ioctx);
+ close(aio_ev->epoll_fd);
+ aio_ev->epoll_fd = -1;
+ return 0;
+}
+
+static void epoll_add_event(struct aio_event_context *aio_ev, struct fd_event *fde);
+
+/*
+ reopen the epoll handle when our pid changes
+ see http://junkcode.samba.org/ftp/unpacked/junkcode/epoll_fork.c for an
+ demonstration of why this is needed
+ */
+static void epoll_check_reopen(struct aio_event_context *aio_ev)
+{
+ struct fd_event *fde;
+
+ if (aio_ev->pid == getpid()) {
+ return;
+ }
+
+ close(aio_ev->epoll_fd);
+ aio_ev->epoll_fd = epoll_create(MAX_AIO_QUEUE_DEPTH);
+ if (aio_ev->epoll_fd == -1) {
+ ev_debug(aio_ev->ev, EV_DEBUG_FATAL, "Failed to recreate epoll handle after fork\n");
+ return;
+ }
+ aio_ev->pid = getpid();
+ for (fde=aio_ev->fd_events;fde;fde=fde->next) {
+ epoll_add_event(aio_ev, fde);
+ }
+}
+
+#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;
+
+ memset(&event, 0, sizeof(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;
+
+ DLIST_REMOVE(aio_ev->fd_events, fde);
+
+ 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)) {
+ DLIST_ADD(aio_ev->fd_events, fde);
+ epoll_add_event(aio_ev, fde);
+ return;
+ }
+}
+
+static int setup_epoll_wait(struct aio_event_context *aio_ev)
+{
+ if (aio_ev->is_epoll_set) {
+ return 0;
+ }
+ 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 = MAX_AIO_QUEUE_DEPTH;
+ 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;
+ }
+ aio_ev->is_epoll_set = 1;
+
+ return 0;
+}
+
+
+/*
+ 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;
+ struct io_event events[8];
+
+ if (aio_ev->epoll_fd == -1) return -1;
+
+ if (aio_ev->ev->num_signal_handlers &&
+ common_event_check_signal(aio_ev->ev)) {
+ return 0;
+ }
+
+ if (tvalp) {
+ timeout.tv_sec = tvalp->tv_sec;
+ timeout.tv_nsec = tvalp->tv_usec;
+ timeout.tv_nsec *= 1000;
+ }
+
+ if (setup_epoll_wait(aio_ev) < 0)
+ return -1;
+
+ ret = io_getevents(aio_ev->ioctx, 1, 8,
+ events, tvalp?&timeout:NULL);
+
+ if (ret == -EINTR) {
+ if (aio_ev->ev->num_signal_handlers) {
+ common_event_check_signal(aio_ev->ev);
+ }
+ return 0;
+ }
+
+ if (ret == 0 && tvalp) {
+ /* we don't care about a possible delay here */
+ common_event_loop_timer_delay(aio_ev->ev);
+ return 0;
+ }
+
+ for (i=0;i<ret;i++) {
+ struct io_event *event = &events[i];
+ struct iocb *finished = event->obj;
+
+ switch (finished->aio_lio_opcode) {
+ case IO_CMD_PWRITE:
+ case IO_CMD_PREAD: {
+ struct aio_event *ae = talloc_get_type(finished->data,
+ struct aio_event);
+ if (ae) {
+ talloc_set_destructor(ae, NULL);
+ ae->handler(ae->event_ctx, ae,
+ event->res, ae->private_data);
+ talloc_free(ae);
+ }
+ break;
+ }
+ case IOCB_CMD_EPOLL_WAIT: {
+ struct epoll_event *ep = (struct epoll_event *)finished->u.c.buf;
+ struct fd_event *fde;
+ uint16_t flags = 0;
+ int j;
+
+ aio_ev->is_epoll_set = 0;
+
+ for (j=0; j<event->res; j++, ep++) {
+ fde = talloc_get_type(ep->data.ptr,
+ struct fd_event);
+ 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);
+ }
+ }
+ break;
+ }
+ }
+ if (destruction_count != aio_ev->destruction_count) {
+ return 0;
+ }
+ }
+
+ return 0;
+}
+
+/*
+ create a aio_event_context structure.
+*/
+static int aio_event_context_init(struct event_context *ev)
+{
+ 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) {
+ talloc_free(aio_ev);
+ return -1;
+ }
+
+ aio_ev->epoll_fd = epoll_create(MAX_AIO_QUEUE_DEPTH);
+ if (aio_ev->epoll_fd == -1) {
+ talloc_free(aio_ev);
+ return -1;
+ }
+ aio_ev->pid = getpid();
+
+ talloc_set_destructor(aio_ev, aio_ctx_destructor);
+
+ ev->additional_data = aio_ev;
+
+ if (setup_epoll_wait(aio_ev) < 0) {
+ talloc_free(aio_ev);
+ return -1;
+ }
+
+ 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);
+
+ epoll_check_reopen(aio_ev);
+
+ aio_ev->num_fd_events--;
+ aio_ev->destruction_count++;
+
+ epoll_del_event(aio_ev, fde);
+
+ 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 *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;
+
+ epoll_check_reopen(aio_ev);
+
+ 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);
+
+ DLIST_ADD(aio_ev->fd_events, fde);
+ 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_check_reopen(aio_ev);
+
+ epoll_change_event(aio_ev, fde);
+}
+
+/*
+ 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;
+
+ tval = common_event_loop_timer_delay(ev);
+ if (ev_timeval_is_zero(&tval)) {
+ return 0;
+ }
+
+ epoll_check_reopen(aio_ev);
+
+ 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;
+}
+
+/*
+ called when a disk IO event needs to be cancelled
+*/
+static int aio_destructor(struct aio_event *ae)
+{
+ struct event_context *ev = ae->event_ctx;
+ struct aio_event_context *aio_ev = talloc_get_type(ev->additional_data,
+ struct aio_event_context);
+ struct io_event result;
+ io_cancel(aio_ev->ioctx, &ae->iocb, &result);
+ /* TODO: handle errors from io_cancel()! */
+ return 0;
+}
+
+/* submit an aio disk IO event */
+static struct aio_event *aio_event_add_aio(struct event_context *ev,
+ TALLOC_CTX *mem_ctx,
+ struct iocb *iocb,
+ event_aio_handler_t handler,
+ void *private_data)
+{
+ struct aio_event_context *aio_ev = talloc_get_type(ev->additional_data,
+ struct aio_event_context);
+ struct iocb *iocbp;
+ struct aio_event *ae = talloc(mem_ctx?mem_ctx:ev, struct aio_event);
+ if (ae == NULL) return NULL;
+
+ ae->event_ctx = ev;
+ ae->iocb = *iocb;
+ ae->handler = handler;
+ ae->private_data = private_data;
+ iocbp = &ae->iocb;
+
+ if (io_submit(aio_ev->ioctx, 1, &iocbp) != 1) {
+ talloc_free(ae);
+ return NULL;
+ }
+ ae->iocb.data = ae;
+ talloc_set_destructor(ae, aio_destructor);
+
+ return ae;
+}
+
+static const struct event_ops aio_event_ops = {
+ .context_init = aio_event_context_init,
+ .add_fd = aio_event_add_fd,
+ .add_aio = aio_event_add_aio,
+ .get_fd_flags = aio_event_get_fd_flags,
+ .set_fd_flags = aio_event_set_fd_flags,
+ .add_timed = common_event_add_timed,
+ .add_signal = common_event_add_signal,
+ .loop_once = aio_event_loop_once,
+ .loop_wait = aio_event_loop_wait,
+};
+
+bool events_aio_init(void)
+{
+ return event_register_backend("aio", &aio_event_ops);
+}
+