1 files changed, 695 insertions, 0 deletions

diff --git a/lib/tevent/tevent_poll.c b/lib/tevent/tevent_poll.c
new file mode 100644
index 0000000..91a9381
--- /dev/null
+++ b/lib/tevent/tevent_poll.c
@@ -0,0 +1,695 @@
+/*
+   Unix SMB/CIFS implementation.
+   main select loop and event handling
+   Copyright (C) Andrew Tridgell	2003-2005
+   Copyright (C) Stefan Metzmacher	2005-2009
+
+     ** NOTE! The following LGPL license applies to the tevent
+     ** library. This does NOT imply that all of Samba is released
+     ** under the LGPL
+
+   This library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 3 of the License, or (at your option) any later version.
+
+   This library 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with this library; if not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include "replace.h"
+#include "system/filesys.h"
+#include "system/select.h"
+#include "tevent.h"
+#include "tevent_util.h"
+#include "tevent_internal.h"
+
+struct poll_event_context {
+	/* a pointer back to the generic event_context */
+	struct tevent_context *ev;
+
+	/*
+	 * one or more events were deleted or disabled
+	 */
+	bool deleted;
+
+	/*
+	 * These two arrays are maintained together.
+	 *
+	 * The following is always true:
+	 * num_fds <= num_fdes
+	 *
+	 * new 'fresh' elements are added at the end
+	 * of the 'fdes' array and picked up later
+	 * to the 'fds' array in poll_event_sync_arrays()
+	 * before the poll() syscall.
+	 */
+	struct pollfd *fds;
+	size_t num_fds;
+	struct tevent_fd **fdes;
+	size_t num_fdes;
+
+	/*
+	 * use tevent_common_wakeup(ev) to wake the poll() thread
+	 */
+	bool use_mt_mode;
+};
+
+/*
+  create a poll_event_context structure.
+*/
+static int poll_event_context_init(struct tevent_context *ev)
+{
+	struct poll_event_context *poll_ev;
+
+	/*
+	 * we might be called during tevent_re_initialise()
+	 * which means we need to free our old additional_data
+	 * in order to detach old fd events from the
+	 * poll_ev->fresh list
+	 */
+	TALLOC_FREE(ev->additional_data);
+
+	poll_ev = talloc_zero(ev, struct poll_event_context);
+	if (poll_ev == NULL) {
+		return -1;
+	}
+	poll_ev->ev = ev;
+	ev->additional_data = poll_ev;
+	return 0;
+}
+
+static int poll_event_context_init_mt(struct tevent_context *ev)
+{
+	struct poll_event_context *poll_ev;
+	int ret;
+
+	ret = poll_event_context_init(ev);
+	if (ret == -1) {
+		return ret;
+	}
+
+	poll_ev = talloc_get_type_abort(
+		ev->additional_data, struct poll_event_context);
+
+	ret = tevent_common_wakeup_init(ev);
+	if (ret != 0) {
+		return ret;
+	}
+
+	poll_ev->use_mt_mode = true;
+
+	return 0;
+}
+
+static void poll_event_wake_pollthread(struct poll_event_context *poll_ev)
+{
+	if (!poll_ev->use_mt_mode) {
+		return;
+	}
+	tevent_common_wakeup(poll_ev->ev);
+}
+
+/*
+  destroy an fd_event
+*/
+static int poll_event_fd_destructor(struct tevent_fd *fde)
+{
+	struct tevent_context *ev = fde->event_ctx;
+	struct poll_event_context *poll_ev;
+	uint64_t del_idx = fde->additional_flags;
+
+	if (ev == NULL) {
+		goto done;
+	}
+
+	poll_ev = talloc_get_type_abort(
+		ev->additional_data, struct poll_event_context);
+
+	if (del_idx == UINT64_MAX) {
+		goto done;
+	}
+
+	poll_ev->fdes[del_idx] = NULL;
+	poll_ev->deleted = true;
+	poll_event_wake_pollthread(poll_ev);
+done:
+	return tevent_common_fd_destructor(fde);
+}
+
+static void poll_event_schedule_immediate(struct tevent_immediate *im,
+					  struct tevent_context *ev,
+					  tevent_immediate_handler_t handler,
+					  void *private_data,
+					  const char *handler_name,
+					  const char *location)
+{
+	struct poll_event_context *poll_ev = talloc_get_type_abort(
+		ev->additional_data, struct poll_event_context);
+
+	tevent_common_schedule_immediate(im, ev, handler, private_data,
+					 handler_name, location);
+	poll_event_wake_pollthread(poll_ev);
+}
+
+/*
+  Private function called by "standard" backend fallback.
+  Note this only allows fallback to "poll" backend, not "poll-mt".
+*/
+_PRIVATE_ bool tevent_poll_event_add_fd_internal(struct tevent_context *ev,
+						 struct tevent_fd *fde)
+{
+	struct poll_event_context *poll_ev = talloc_get_type_abort(
+		ev->additional_data, struct poll_event_context);
+	uint64_t fde_idx = UINT64_MAX;
+	size_t num_fdes;
+
+	fde->additional_flags = UINT64_MAX;
+	tevent_common_fd_mpx_reinit(fde);
+	talloc_set_destructor(fde, poll_event_fd_destructor);
+
+	if (fde->flags == 0) {
+		/*
+		 * Nothing more to do...
+		 */
+		return true;
+	}
+
+	/*
+	 * We need to add it to the end of the 'fdes' array.
+	 */
+	num_fdes = poll_ev->num_fdes + 1;
+	if (num_fdes > talloc_array_length(poll_ev->fdes)) {
+		struct tevent_fd **tmp_fdes = NULL;
+		size_t array_length;
+
+		array_length = (num_fdes + 15) & ~15; /* round up to 16 */
+
+		tmp_fdes = talloc_realloc(poll_ev,
+					  poll_ev->fdes,
+					  struct tevent_fd *,
+					  array_length);
+		if (tmp_fdes == NULL) {
+			return false;
+		}
+		poll_ev->fdes = tmp_fdes;
+	}
+
+	fde_idx = poll_ev->num_fdes;
+	fde->additional_flags = fde_idx;
+	poll_ev->fdes[fde_idx] = fde;
+	poll_ev->num_fdes++;
+
+	return true;
+}
+
+/*
+  add a fd based event
+  return NULL on failure (memory allocation error)
+*/
+static struct tevent_fd *poll_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 poll_event_context *poll_ev = talloc_get_type_abort(
+		ev->additional_data, struct poll_event_context);
+	struct tevent_fd *fde;
+	bool ok;
+
+	if (fd < 0) {
+		return NULL;
+	}
+
+	fde = tevent_common_add_fd(ev,
+				   mem_ctx,
+				   fd,
+				   flags,
+				   handler,
+				   private_data,
+				   handler_name,
+				   location);
+	if (fde == NULL) {
+		return NULL;
+	}
+
+	ok = tevent_poll_event_add_fd_internal(ev, fde);
+	if (!ok) {
+		TALLOC_FREE(fde);
+		return NULL;
+	}
+	poll_event_wake_pollthread(poll_ev);
+
+	/*
+	 * poll_event_loop_poll will take care of the rest in
+	 * poll_event_setup_fresh
+	 */
+	return fde;
+}
+
+/*
+  map from TEVENT_FD_* to POLLIN/POLLOUT
+*/
+static uint16_t poll_map_flags(uint16_t flags)
+{
+	uint16_t pollflags = 0;
+
+	/*
+	 * we do not need to specify POLLERR | POLLHUP
+	 * they are always reported.
+	 */
+
+	if (flags & TEVENT_FD_READ) {
+		pollflags |= POLLIN;
+#ifdef POLLRDHUP
+		/*
+		 * Note that at least on Linux
+		 * POLLRDHUP always returns
+		 * POLLIN in addition, so this
+		 * is not strictly needed, but
+		 * we want to make it explicit.
+		 */
+		pollflags |= POLLRDHUP;
+#endif
+	}
+	if (flags & TEVENT_FD_WRITE) {
+		pollflags |= POLLOUT;
+	}
+	if (flags & TEVENT_FD_ERROR) {
+#ifdef POLLRDHUP
+		pollflags |= POLLRDHUP;
+#endif
+	}
+
+	return pollflags;
+}
+
+/*
+  set the fd event flags
+*/
+static void poll_event_set_fd_flags(struct tevent_fd *fde, uint16_t flags)
+{
+	struct tevent_context *ev = fde->event_ctx;
+	struct poll_event_context *poll_ev;
+	uint64_t idx = fde->additional_flags;
+
+	if (ev == NULL) {
+		return;
+	}
+
+	if (fde->flags == flags) {
+		return;
+	}
+
+	poll_ev = talloc_get_type_abort(
+		ev->additional_data, struct poll_event_context);
+
+	fde->flags = flags;
+
+	if (idx == UINT64_MAX) {
+		/*
+		 * We move it between the fresh and disabled lists.
+		 */
+		tevent_poll_event_add_fd_internal(ev, fde);
+		poll_event_wake_pollthread(poll_ev);
+		return;
+	}
+
+	if (fde->flags == 0) {
+		/*
+		 * We need to remove it from the array
+		 * and move it to the disabled list.
+		 */
+		poll_ev->fdes[idx] = NULL;
+		poll_ev->deleted = true;
+		fde->additional_flags = UINT64_MAX;
+		poll_event_wake_pollthread(poll_ev);
+		return;
+	}
+
+	if (idx >= poll_ev->num_fds) {
+		/*
+		 * Not yet added to the
+		 * poll_ev->fds array.
+		 */
+		poll_event_wake_pollthread(poll_ev);
+		return;
+	}
+
+	poll_ev->fds[idx].events = poll_map_flags(flags);
+
+	poll_event_wake_pollthread(poll_ev);
+}
+
+static bool poll_event_sync_arrays(struct tevent_context *ev,
+				   struct poll_event_context *poll_ev)
+{
+	size_t i;
+	size_t array_length;
+
+	if (poll_ev->deleted) {
+
+		for (i=0; i < poll_ev->num_fds;) {
+			struct tevent_fd *fde = poll_ev->fdes[i];
+			size_t ci;
+
+			if (fde != NULL) {
+				i++;
+				continue;
+			}
+
+			/*
+			 * This fde was talloc_free()'ed. Delete it
+			 * from the arrays
+			 */
+			poll_ev->num_fds -= 1;
+			ci = poll_ev->num_fds;
+			if (ci > i) {
+				poll_ev->fds[i] = poll_ev->fds[ci];
+				poll_ev->fdes[i] = poll_ev->fdes[ci];
+				if (poll_ev->fdes[i] != NULL) {
+					poll_ev->fdes[i]->additional_flags = i;
+				}
+			}
+			poll_ev->fds[ci] = (struct pollfd) { .fd = -1 };
+			poll_ev->fdes[ci] = NULL;
+		}
+		poll_ev->deleted = false;
+	}
+
+	if (poll_ev->num_fds == poll_ev->num_fdes) {
+		return true;
+	}
+
+	/*
+	 * Recheck the size of both arrays and make sure
+	 * poll_fd->fds array has at least the size of the
+	 * in use poll_ev->fdes array.
+	 */
+	if (poll_ev->num_fdes > talloc_array_length(poll_ev->fds)) {
+		struct pollfd *tmp_fds = NULL;
+
+		/*
+		 * Make sure both allocated the same length.
+		 */
+		array_length = talloc_array_length(poll_ev->fdes);
+
+		tmp_fds = talloc_realloc(poll_ev,
+					 poll_ev->fds,
+					 struct pollfd,
+					 array_length);
+		if (tmp_fds == NULL) {
+			return false;
+		}
+		poll_ev->fds = tmp_fds;
+	}
+
+	/*
+	 * Now setup the new elements.
+	 */
+	for (i = poll_ev->num_fds; i < poll_ev->num_fdes; i++) {
+		struct tevent_fd *fde = poll_ev->fdes[i];
+		struct pollfd *pfd = &poll_ev->fds[poll_ev->num_fds];
+
+		if (fde == NULL) {
+			continue;
+		}
+
+		if (i > poll_ev->num_fds) {
+			poll_ev->fdes[poll_ev->num_fds] = fde;
+			fde->additional_flags = poll_ev->num_fds;
+			poll_ev->fdes[i] = NULL;
+		}
+
+		pfd->fd = fde->fd;
+		pfd->events = poll_map_flags(fde->flags);
+		pfd->revents = 0;
+
+		poll_ev->num_fds += 1;
+	}
+	/* Both are in sync again */
+	poll_ev->num_fdes = poll_ev->num_fds;
+
+	/*
+	 * Check if we should shrink the arrays
+	 * But keep at least 16 elements.
+	 */
+
+	array_length = (poll_ev->num_fds + 15) & ~15; /* round up to 16 */
+	array_length = MAX(array_length, 16);
+	if (array_length < talloc_array_length(poll_ev->fdes)) {
+		struct tevent_fd **tmp_fdes = NULL;
+		struct pollfd *tmp_fds = NULL;
+
+		tmp_fdes = talloc_realloc(poll_ev,
+					  poll_ev->fdes,
+					  struct tevent_fd *,
+					  array_length);
+		if (tmp_fdes == NULL) {
+			return false;
+		}
+		poll_ev->fdes = tmp_fdes;
+
+		tmp_fds = talloc_realloc(poll_ev,
+					 poll_ev->fds,
+					 struct pollfd,
+					 array_length);
+		if (tmp_fds == NULL) {
+			return false;
+		}
+		poll_ev->fds = tmp_fds;
+	}
+
+	return true;
+}
+
+/*
+  event loop handling using poll()
+*/
+static int poll_event_loop_poll(struct tevent_context *ev,
+				struct timeval *tvalp)
+{
+	struct poll_event_context *poll_ev = talloc_get_type_abort(
+		ev->additional_data, struct poll_event_context);
+	int pollrtn;
+	int timeout = -1;
+	int poll_errno;
+	struct tevent_fd *fde = NULL;
+	struct tevent_fd *next = NULL;
+	unsigned i;
+	bool ok;
+
+	if (ev->signal_events && tevent_common_check_signal(ev)) {
+		return 0;
+	}
+
+	if (tvalp != NULL) {
+		timeout = tvalp->tv_sec * 1000;
+		timeout += (tvalp->tv_usec + 999) / 1000;
+	}
+
+	ok = poll_event_sync_arrays(ev, poll_ev);
+	if (!ok) {
+		return -1;
+	}
+
+	tevent_trace_point_callback(poll_ev->ev, TEVENT_TRACE_BEFORE_WAIT);
+	pollrtn = poll(poll_ev->fds, poll_ev->num_fds, timeout);
+	poll_errno = errno;
+	tevent_trace_point_callback(poll_ev->ev, TEVENT_TRACE_AFTER_WAIT);
+
+	if (pollrtn == -1 && poll_errno == EINTR && ev->signal_events) {
+		tevent_common_check_signal(ev);
+		return 0;
+	}
+
+	if (pollrtn == 0 && tvalp) {
+		/* we don't care about a possible delay here */
+		tevent_common_loop_timer_delay(ev);
+		return 0;
+	}
+
+	if (pollrtn <= 0) {
+		/*
+		 * No fd's ready
+		 */
+		return 0;
+	}
+
+	/* at least one file descriptor is ready - check
+	   which ones and call the handler, being careful to allow
+	   the handler to remove itself when called */
+
+	for (fde = ev->fd_events; fde; fde = next) {
+		uint64_t idx = fde->additional_flags;
+		struct pollfd *pfd;
+		uint16_t flags = 0;
+
+		next = fde->next;
+
+		if (idx == UINT64_MAX) {
+			continue;
+		}
+
+		pfd = &poll_ev->fds[idx];
+
+		if (pfd->revents & POLLNVAL) {
+			/*
+			 * the socket is dead! this should never
+			 * happen as the socket should have first been
+			 * made readable and that should have removed
+			 * the event, so this must be a bug.
+			 *
+			 * We ignore it here to match the epoll
+			 * behavior.
+			 */
+			tevent_debug(ev, TEVENT_DEBUG_ERROR,
+				     "POLLNVAL on fde[%p] fd[%d] - disabling\n",
+				     fde, pfd->fd);
+			poll_ev->fdes[idx] = NULL;
+			poll_ev->deleted = true;
+			tevent_common_fd_disarm(fde);
+			continue;
+		}
+
+#ifdef POLLRDHUP
+#define __POLL_RETURN_ERROR_FLAGS (POLLHUP|POLLERR|POLLRDHUP)
+#else
+#define __POLL_RETURN_ERROR_FLAGS (POLLHUP|POLLERR)
+#endif
+
+		if (pfd->revents & __POLL_RETURN_ERROR_FLAGS) {
+			/*
+			 * If we only wait for TEVENT_FD_WRITE, we
+			 * should not tell the event handler about it,
+			 * and remove the writable flag, as we only
+			 * report errors when waiting for read events
+			 * or explicit for errors.
+			 */
+			if (!(fde->flags & (TEVENT_FD_READ|TEVENT_FD_ERROR)))
+			{
+				TEVENT_FD_NOT_WRITEABLE(fde);
+				continue;
+			}
+			if (fde->flags & TEVENT_FD_ERROR) {
+				flags |= TEVENT_FD_ERROR;
+			}
+			if (fde->flags & TEVENT_FD_READ) {
+				flags |= TEVENT_FD_READ;
+			}
+		}
+		if (pfd->revents & POLLIN) {
+			flags |= TEVENT_FD_READ;
+		}
+		if (pfd->revents & POLLOUT) {
+			flags |= TEVENT_FD_WRITE;
+		}
+		/*
+		 * Note that fde->flags could be changed when using
+		 * the poll_mt backend together with threads,
+		 * that why we need to check pfd->revents and fde->flags
+		 */
+		flags &= fde->flags;
+		if (flags != 0) {
+			DLIST_DEMOTE(ev->fd_events, fde);
+			return tevent_common_invoke_fd_handler(fde, flags, NULL);
+		}
+	}
+
+	for (i = 0; i < poll_ev->num_fds; i++) {
+		if (poll_ev->fds[i].revents & POLLNVAL) {
+			/*
+			 * the socket is dead! this should never
+			 * happen as the socket should have first been
+			 * made readable and that should have removed
+			 * the event, so this must be a bug or
+			 * a race in the poll_mt usage.
+			 */
+			fde = poll_ev->fdes[i];
+			tevent_debug(ev, TEVENT_DEBUG_WARNING,
+				     "POLLNVAL on dangling fd[%d] fde[%p] - disabling\n",
+				     poll_ev->fds[i].fd, fde);
+			poll_ev->fdes[i] = NULL;
+			poll_ev->deleted = true;
+			if (fde != NULL) {
+				tevent_common_fd_disarm(fde);
+			}
+		}
+	}
+
+	return 0;
+}
+
+/*
+  do a single event loop using the events defined in ev
+*/
+static int poll_event_loop_once(struct tevent_context *ev,
+				const char *location)
+{
+	struct timeval tval;
+
+	if (ev->signal_events &&
+	    tevent_common_check_signal(ev)) {
+		return 0;
+	}
+
+	if (ev->threaded_contexts != NULL) {
+		tevent_common_threaded_activate_immediate(ev);
+	}
+
+	if (ev->immediate_events &&
+	    tevent_common_loop_immediate(ev)) {
+		return 0;
+	}
+
+	tval = tevent_common_loop_timer_delay(ev);
+	if (tevent_timeval_is_zero(&tval)) {
+		return 0;
+	}
+
+	return poll_event_loop_poll(ev, &tval);
+}
+
+static const struct tevent_ops poll_event_ops = {
+	.context_init		= poll_event_context_init,
+	.add_fd			= poll_event_add_fd,
+	.set_fd_close_fn	= tevent_common_fd_set_close_fn,
+	.get_fd_flags		= tevent_common_fd_get_flags,
+	.set_fd_flags		= poll_event_set_fd_flags,
+	.add_timer		= tevent_common_add_timer_v2,
+	.schedule_immediate	= tevent_common_schedule_immediate,
+	.add_signal		= tevent_common_add_signal,
+	.loop_once		= poll_event_loop_once,
+	.loop_wait		= tevent_common_loop_wait,
+};
+
+_PRIVATE_ bool tevent_poll_init(void)
+{
+	return tevent_register_backend("poll", &poll_event_ops);
+}
+
+static const struct tevent_ops poll_event_mt_ops = {
+	.context_init		= poll_event_context_init_mt,
+	.add_fd			= poll_event_add_fd,
+	.set_fd_close_fn	= tevent_common_fd_set_close_fn,
+	.get_fd_flags		= tevent_common_fd_get_flags,
+	.set_fd_flags		= poll_event_set_fd_flags,
+	.add_timer		= tevent_common_add_timer_v2,
+	.schedule_immediate	= poll_event_schedule_immediate,
+	.add_signal		= tevent_common_add_signal,
+	.loop_once		= poll_event_loop_once,
+	.loop_wait		= tevent_common_loop_wait,
+};
+
+_PRIVATE_ bool tevent_poll_mt_init(void)
+{
+	return tevent_register_backend("poll_mt", &poll_event_mt_ops);
+}