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tevent_poll: Decouple poll_ev->fds handling from adding/removing fds
Step 1 in a python backend for multiple threads Signed-off-by: Stefan Metzmacher <metze@samba.org>
This commit is contained in:
Volker Lendecke
Stefan Metzmacher
parent
cbe25105c7
commit
d860aa2cac
@ -33,12 +33,17 @@ struct poll_event_context {
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/* a pointer back to the generic event_context */
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struct tevent_context *ev;
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/*
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* A DLIST for fresh fde's
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*/
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struct tevent_fd *fresh;
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/*
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* These two arrays are maintained together.
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*/
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struct pollfd *fds;
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struct tevent_fd **fd_events;
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uint64_t num_fds;
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struct tevent_fd **fdes;
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unsigned num_fds;
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/* information for exiting from the event loop */
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int exit_code;
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@ -67,7 +72,6 @@ static int poll_event_fd_destructor(struct tevent_fd *fde)
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{
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struct tevent_context *ev = fde->event_ctx;
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struct poll_event_context *poll_ev = NULL;
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struct tevent_fd *moved_fde;
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uint64_t del_idx = fde->additional_flags;
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if (ev == NULL) {
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@ -77,16 +81,19 @@ static int poll_event_fd_destructor(struct tevent_fd *fde)
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poll_ev = talloc_get_type_abort(
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ev->additional_data, struct poll_event_context);
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moved_fde = poll_ev->fd_events[poll_ev->num_fds-1];
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poll_ev->fd_events[del_idx] = moved_fde;
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poll_ev->fds[del_idx] = poll_ev->fds[poll_ev->num_fds-1];
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moved_fde->additional_flags = del_idx;
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poll_ev->num_fds -= 1;
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poll_ev->fdes[del_idx] = NULL;
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done:
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return tevent_common_fd_destructor(fde);
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}
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static int poll_fresh_fde_destructor(struct tevent_fd *fde)
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{
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struct poll_event_context *poll_ev = talloc_get_type_abort(
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fde->event_ctx->additional_data, struct poll_event_context);
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DLIST_REMOVE(poll_ev->fresh, fde);
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return 0;
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}
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/*
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add a fd based event
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return NULL on failure (memory allocation error)
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@ -101,60 +108,34 @@ static struct tevent_fd *poll_event_add_fd(struct tevent_context *ev,
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{
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struct poll_event_context *poll_ev = talloc_get_type_abort(
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ev->additional_data, struct poll_event_context);
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struct pollfd *pfd;
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struct tevent_fd *fde;
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fde = tevent_common_add_fd(ev, mem_ctx, fd, flags,
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handler, private_data,
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handler_name, location);
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if (fde == NULL) {
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if (fd < 0) {
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return NULL;
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}
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/* we allocate 16 slots to avoid a lot of reallocations */
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if (talloc_array_length(poll_ev->fds) == poll_ev->num_fds) {
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struct pollfd *tmp_fds;
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struct tevent_fd **tmp_fd_events;
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tmp_fds = talloc_realloc(
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poll_ev, poll_ev->fds, struct pollfd,
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poll_ev->num_fds + 16);
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if (tmp_fds == NULL) {
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TALLOC_FREE(fde);
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return NULL;
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}
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poll_ev->fds = tmp_fds;
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tmp_fd_events = talloc_realloc(
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poll_ev, poll_ev->fd_events, struct tevent_fd *,
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poll_ev->num_fds + 16);
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if (tmp_fd_events == NULL) {
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TALLOC_FREE(fde);
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return NULL;
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}
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poll_ev->fd_events = tmp_fd_events;
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fde = talloc(mem_ctx ? mem_ctx : ev, struct tevent_fd);
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if (fde == NULL) {
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return NULL;
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}
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fde->event_ctx = ev;
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fde->fd = fd;
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fde->flags = flags;
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fde->handler = handler;
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fde->close_fn = NULL;
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fde->private_data = private_data;
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fde->handler_name = handler_name;
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fde->location = location;
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fde->additional_flags = 0;
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fde->additional_data = NULL;
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pfd = &poll_ev->fds[poll_ev->num_fds];
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pfd->fd = fd;
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pfd->events = 0;
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pfd->revents = 0;
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if (flags & TEVENT_FD_READ) {
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pfd->events |= (POLLIN|POLLHUP);
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}
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if (flags & TEVENT_FD_WRITE) {
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pfd->events |= (POLLOUT);
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}
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fde->additional_flags = poll_ev->num_fds;
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poll_ev->fd_events[poll_ev->num_fds] = fde;
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poll_ev->num_fds += 1;
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talloc_set_destructor(fde, poll_event_fd_destructor);
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DLIST_ADD(poll_ev->fresh, fde);
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talloc_set_destructor(fde, poll_fresh_fde_destructor);
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/*
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* poll_event_loop_poll will take care of the rest in
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* poll_event_setup_fresh
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*/
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return fde;
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}
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@ -180,6 +161,81 @@ static void poll_event_set_fd_flags(struct tevent_fd *fde, uint16_t flags)
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fde->flags = flags;
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}
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static bool poll_event_setup_fresh(struct tevent_context *ev,
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struct poll_event_context *poll_ev)
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{
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struct tevent_fd *fde, *next;
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unsigned num_fresh, num_fds;
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if (poll_ev->fresh == NULL) {
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return true;
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}
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num_fresh = 0;
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for (fde = poll_ev->fresh; fde; fde = fde->next) {
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num_fresh += 1;
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}
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num_fds = poll_ev->num_fds + num_fresh;
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/*
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* We check the length of fdes here. It is the last one
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* enlarged, so if the realloc for poll_fd->fdes fails,
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* poll_fd->fds will have at least the size of poll_fd->fdes
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*/
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if (num_fds >= talloc_array_length(poll_ev->fdes)) {
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struct pollfd *tmp_fds;
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struct tevent_fd **tmp_fdes;
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unsigned array_length;
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array_length = (num_fds + 15) & ~15; /* round up to 16 */
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tmp_fds = talloc_realloc(
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poll_ev, poll_ev->fds, struct pollfd, array_length);
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if (tmp_fds == NULL) {
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return false;
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}
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poll_ev->fds = tmp_fds;
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tmp_fdes = talloc_realloc(
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poll_ev, poll_ev->fdes, struct tevent_fd *,
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array_length);
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if (tmp_fdes == NULL) {
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return false;
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}
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poll_ev->fdes = tmp_fdes;
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}
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for (fde = poll_ev->fresh; fde; fde = next) {
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struct pollfd *pfd;
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pfd = &poll_ev->fds[poll_ev->num_fds];
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pfd->fd = fde->fd;
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pfd->events = 0;
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pfd->revents = 0;
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if (fde->flags & TEVENT_FD_READ) {
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pfd->events |= (POLLIN|POLLHUP);
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}
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if (fde->flags & TEVENT_FD_WRITE) {
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pfd->events |= (POLLOUT);
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}
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fde->additional_flags = poll_ev->num_fds;
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poll_ev->fdes[poll_ev->num_fds] = fde;
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next = fde->next;
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DLIST_REMOVE(poll_ev->fresh, fde);
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DLIST_ADD(ev->fd_events, fde);
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talloc_set_destructor(fde, poll_event_fd_destructor);
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poll_ev->num_fds += 1;
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}
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return true;
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}
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/*
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event loop handling using poll()
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*/
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@ -188,9 +244,9 @@ static int poll_event_loop_poll(struct tevent_context *ev,
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{
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struct poll_event_context *poll_ev = talloc_get_type_abort(
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ev->additional_data, struct poll_event_context);
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struct tevent_fd *fde;
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int pollrtn;
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int timeout = -1;
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unsigned i;
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if (ev->signal_events && tevent_common_check_signal(ev)) {
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return 0;
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@ -201,6 +257,10 @@ static int poll_event_loop_poll(struct tevent_context *ev,
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timeout += (tvalp->tv_usec + 999) / 1000;
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}
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if (!poll_event_setup_fresh(ev, poll_ev)) {
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return -1;
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}
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tevent_trace_point_callback(poll_ev->ev, TEVENT_TRACE_BEFORE_WAIT);
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pollrtn = poll(poll_ev->fds, poll_ev->num_fds, timeout);
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tevent_trace_point_callback(poll_ev->ev, TEVENT_TRACE_AFTER_WAIT);
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@ -210,18 +270,6 @@ static int poll_event_loop_poll(struct tevent_context *ev,
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return 0;
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}
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if (pollrtn == -1 && errno == EBADF) {
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/* the socket is dead! this should never
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happen as the socket should have first been
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made readable and that should have removed
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the event, so this must be a bug. This is a
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fatal error. */
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tevent_debug(ev, TEVENT_DEBUG_FATAL,
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"ERROR: EBADF on poll_event_loop_once\n");
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poll_ev->exit_code = EBADF;
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return -1;
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}
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if (pollrtn == 0 && tvalp) {
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/* we don't care about a possible delay here */
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tevent_common_loop_timer_delay(ev);
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@ -239,12 +287,27 @@ static int poll_event_loop_poll(struct tevent_context *ev,
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which ones and call the handler, being careful to allow
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the handler to remove itself when called */
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for (fde = ev->fd_events; fde; fde = fde->next) {
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for (i=0; i<poll_ev->num_fds; i++) {
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struct pollfd *pfd;
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uint64_t pfd_idx = fde->additional_flags;
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struct tevent_fd *fde;
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uint16_t flags = 0;
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pfd = &poll_ev->fds[pfd_idx];
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fde = poll_ev->fdes[i];
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if (fde == NULL) {
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/*
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* This fde was talloc_free()'ed. Delete it
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* from the arrays
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*/
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poll_ev->num_fds -= 1;
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poll_ev->fds[i] = poll_ev->fds[poll_ev->num_fds];
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poll_ev->fdes[i] = poll_ev->fdes[poll_ev->num_fds];
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if (poll_ev->fdes[i] != NULL) {
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poll_ev->fdes[i]->additional_flags = i;
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}
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continue;
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}
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pfd = &poll_ev->fds[i];
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if (pfd->revents & (POLLHUP|POLLERR)) {
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/* If we only wait for TEVENT_FD_WRITE, we
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