+++ /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 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 "replace.h"
-#include "system/filesys.h"
-#include "system/select.h"
-#include "tevent.h"
-#include "tevent_internal.h"
-#include "tevent_util.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 tevent_context *ev;
-
- 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 tevent_aio {
- struct tevent_context *event_ctx;
- struct iocb iocb;
- void *private_data;
- tevent_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 & TEVENT_FD_READ) ret |= (EPOLLIN | EPOLLERR | EPOLLHUP);
- if (flags & TEVENT_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 tevent_fd *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 tevent_fd *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) {
- tevent_debug(aio_ev->ev, TEVENT_DEBUG_FATAL,
- "Failed to recreate epoll handle after fork\n");
- return;
- }
- aio_ev->pid = getpid();
- for (fde=aio_ev->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 tevent_fd *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 & TEVENT_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 tevent_fd *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 tevent_fd *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 & TEVENT_FD_READ) {
- fde->additional_flags |= EPOLL_ADDITIONAL_FD_FLAG_REPORT_ERROR;
- }
-}
-
-static void epoll_change_event(struct aio_event_context *aio_ev, struct tevent_fd *fde)
-{
- bool got_error = (fde->additional_flags & EPOLL_ADDITIONAL_FD_FLAG_GOT_ERROR);
- bool want_read = (fde->flags & TEVENT_FD_READ);
- bool want_write= (fde->flags & TEVENT_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)
-{
- 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->signal_events &&
- tevent_common_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->signal_events) {
- tevent_common_check_signal(aio_ev->ev);
- }
- return 0;
- }
-
- if (ret == 0 && tvalp) {
- /* we don't care about a possible delay here */
- tevent_common_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 tevent_aio *ae = talloc_get_type(finished->data,
- struct tevent_aio);
- 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 tevent_fd *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 tevent_fd);
- 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 |= TEVENT_FD_READ;
- }
- if (ep->events & EPOLLIN) flags |= TEVENT_FD_READ;
- if (ep->events & EPOLLOUT) flags |= TEVENT_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 tevent_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 tevent_fd *fde)
-{
- struct tevent_context *ev = fde->event_ctx;
- struct aio_event_context *aio_ev = NULL;
-
- if (ev) {
- aio_ev = talloc_get_type(ev->additional_data,
- struct aio_event_context);
-
- epoll_check_reopen(aio_ev);
-
- aio_ev->destruction_count++;
-
- epoll_del_event(aio_ev, fde);
- }
-
- return tevent_common_fd_destructor(fde);
-}
-
-/*
- add a fd based event
- return NULL on failure (memory allocation error)
-*/
-static struct tevent_fd *aio_event_add_fd(struct tevent_context *ev, TALLOC_CTX *mem_ctx,
- int fd, uint16_t flags,
- tevent_fd_handler_t handler,
- void *private_data,
- const char *handler_name,
- const char *location)
-{
- struct aio_event_context *aio_ev = talloc_get_type(ev->additional_data,
- struct aio_event_context);
- struct tevent_fd *fde;
-
- epoll_check_reopen(aio_ev);
-
- fde = tevent_common_add_fd(ev, mem_ctx, fd, flags,
- handler, private_data,
- handler_name, location);
- if (!fde) return NULL;
-
- talloc_set_destructor(fde, aio_event_fd_destructor);
-
- epoll_add_event(aio_ev, fde);
-
- return fde;
-}
-
-/*
- set the fd event flags
-*/
-static void aio_event_set_fd_flags(struct tevent_fd *fde, uint16_t flags)
-{
- struct tevent_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 tevent_context *ev)
-{
- struct aio_event_context *aio_ev = talloc_get_type(ev->additional_data,
- struct aio_event_context);
- struct timeval tval;
-
- tval = tevent_common_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 tevent_context *ev)
-{
- struct aio_event_context *aio_ev = talloc_get_type(ev->additional_data,
- struct aio_event_context);
- while (aio_ev->ev->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 tevent_aio *ae)
-{
- struct tevent_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 tevent_aio *aio_event_add_aio(struct tevent_context *ev,
- TALLOC_CTX *mem_ctx,
- struct iocb *iocb,
- tevent_aio_handler_t handler,
- void *private_data,
- const char *handler_name,
- const char *location)
-{
- struct aio_event_context *aio_ev = talloc_get_type(ev->additional_data,
- struct aio_event_context);
- struct iocb *iocbp;
- struct tevent_aio *ae = talloc(mem_ctx?mem_ctx:ev, struct tevent_aio);
- 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 tevent_ops aio_event_ops = {
- .context_init = aio_event_context_init,
- .add_fd = aio_event_add_fd,
- .add_aio = aio_event_add_aio,
- .set_fd_close_fn= tevent_common_fd_set_close_fn,
- .get_fd_flags = tevent_common_fd_get_flags,
- .set_fd_flags = aio_event_set_fd_flags,
- .add_timer = tevent_common_add_timer,
- .add_signal = tevent_common_add_signal,
- .loop_once = aio_event_loop_once,
- .loop_wait = aio_event_loop_wait,
-};
-
-bool tevent_aio_init(void)
-{
- return tevent_register_backend("aio", &aio_event_ops);
-}
-
git.samba.org / metze / samba / wip.git / commitdiff