1 files changed, 277 insertions, 0 deletions
diff --git a/ctdb/lib/tevent/tevent_select.c b/ctdb/lib/tevent/tevent_select.c
new file mode 100644
index 0000000000..bfce246e22
--- /dev/null
+++ b/ctdb/lib/tevent/tevent_select.c
@@ -0,0 +1,277 @@
+/* 
+   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 select_event_context {
+	/* a pointer back to the generic event_context */
+	struct tevent_context *ev;
+
+	/* the maximum file descriptor number in fd_events */
+	int maxfd;
+
+	/* information for exiting from the event loop */
+	int exit_code;
+};
+
+/*
+  create a select_event_context structure.
+*/
+static int select_event_context_init(struct tevent_context *ev)
+{
+	struct select_event_context *select_ev;
+
+	/*
+	 * We might be called during tevent_re_initialise()
+	 * which means we need to free our old additional_data.
+	 */
+	TALLOC_FREE(ev->additional_data);
+
+	select_ev = talloc_zero(ev, struct select_event_context);
+	if (!select_ev) return -1;
+	select_ev->ev = ev;
+
+	ev->additional_data = select_ev;
+	return 0;
+}
+
+/*
+  recalculate the maxfd
+*/
+static void calc_maxfd(struct select_event_context *select_ev)
+{
+	struct tevent_fd *fde;
+
+	select_ev->maxfd = 0;
+	for (fde = select_ev->ev->fd_events; fde; fde = fde->next) {
+		if (fde->fd > select_ev->maxfd) {
+			select_ev->maxfd = fde->fd;
+		}
+	}
+}
+
+
+/* to mark the ev->maxfd invalid
+ * this means we need to recalculate it
+ */
+#define EVENT_INVALID_MAXFD (-1)
+
+/*
+  destroy an fd_event
+*/
+static int select_event_fd_destructor(struct tevent_fd *fde)
+{
+	struct tevent_context *ev = fde->event_ctx;
+	struct select_event_context *select_ev = NULL;
+
+	if (ev) {
+		select_ev = talloc_get_type(ev->additional_data,
+					    struct select_event_context);
+
+		if (select_ev->maxfd == fde->fd) {
+			select_ev->maxfd = EVENT_INVALID_MAXFD;
+		}
+	}
+
+	return tevent_common_fd_destructor(fde);
+}
+
+/*
+  add a fd based event
+  return NULL on failure (memory allocation error)
+*/
+static struct tevent_fd *select_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 select_event_context *select_ev = talloc_get_type(ev->additional_data,
+							   struct select_event_context);
+	struct tevent_fd *fde;
+
+	if (fd < 0 || fd >= FD_SETSIZE) {
+		errno = EBADF;
+		return NULL;
+	}
+
+	fde = tevent_common_add_fd(ev, mem_ctx, fd, flags,
+				   handler, private_data,
+				   handler_name, location);
+	if (!fde) return NULL;
+
+	if ((select_ev->maxfd != EVENT_INVALID_MAXFD)
+	    && (fde->fd > select_ev->maxfd)) {
+		select_ev->maxfd = fde->fd;
+	}
+	talloc_set_destructor(fde, select_event_fd_destructor);
+
+	return fde;
+}
+
+/*
+  event loop handling using select()
+*/
+static int select_event_loop_select(struct select_event_context *select_ev, struct timeval *tvalp)
+{
+	fd_set r_fds, w_fds;
+	struct tevent_fd *fde;
+	int selrtn;
+	int select_errno;
+
+	/* we maybe need to recalculate the maxfd */
+	if (select_ev->maxfd == EVENT_INVALID_MAXFD) {
+		calc_maxfd(select_ev);
+	}
+
+	FD_ZERO(&r_fds);
+	FD_ZERO(&w_fds);
+
+	/* setup any fd events */
+	for (fde = select_ev->ev->fd_events; fde; fde = fde->next) {
+		if (fde->fd < 0 || fde->fd >= FD_SETSIZE) {
+			tevent_debug(select_ev->ev, TEVENT_DEBUG_FATAL,
+				     "ERROR: EBADF fd[%d] >= %d "
+				     "select_event_loop_once\n",
+				     fde->fd, FD_SETSIZE);
+			errno = EBADF;
+			return -1;
+		}
+
+		if (fde->flags & TEVENT_FD_READ) {
+			FD_SET(fde->fd, &r_fds);
+		}
+		if (fde->flags & TEVENT_FD_WRITE) {
+			FD_SET(fde->fd, &w_fds);
+		}
+	}
+
+	if (select_ev->ev->signal_events &&
+	    tevent_common_check_signal(select_ev->ev)) {
+		return 0;
+	}
+
+	tevent_trace_point_callback(select_ev->ev, TEVENT_TRACE_BEFORE_WAIT);
+	selrtn = select(select_ev->maxfd+1, &r_fds, &w_fds, NULL, tvalp);
+	select_errno = errno;
+	tevent_trace_point_callback(select_ev->ev, TEVENT_TRACE_AFTER_WAIT);
+
+	if (selrtn == -1 && select_errno == EINTR &&
+	    select_ev->ev->signal_events) {
+		tevent_common_check_signal(select_ev->ev);
+		return 0;
+	}
+
+	if (selrtn == -1 && select_errno == EBADF) {
+		/* 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. This is a
+		   fatal error. */
+		tevent_debug(select_ev->ev, TEVENT_DEBUG_FATAL,
+			     "ERROR: EBADF on select_event_loop_once\n");
+		select_ev->exit_code = EBADF;
+		return -1;
+	}
+
+	if (selrtn == 0 && tvalp) {
+		/* we don't care about a possible delay here */
+		tevent_common_loop_timer_delay(select_ev->ev);
+		return 0;
+	}
+
+	if (selrtn > 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 = select_ev->ev->fd_events; fde; fde = fde->next) {
+			uint16_t flags = 0;
+
+			if (FD_ISSET(fde->fd, &r_fds) && (fde->flags & TEVENT_FD_READ)) {
+				flags |= TEVENT_FD_READ;
+			}
+			if (FD_ISSET(fde->fd, &w_fds) && (fde->flags & TEVENT_FD_WRITE)) {
+				flags |= TEVENT_FD_WRITE;
+			}
+			if (flags) {
+				DLIST_DEMOTE(select_ev->ev->fd_events, fde, struct tevent_fd);
+				fde->handler(select_ev->ev, fde, flags, fde->private_data);
+				break;
+			}
+		}
+	}
+
+	return 0;
+}
+
+/*
+  do a single event loop using the events defined in ev 
+*/
+static int select_event_loop_once(struct tevent_context *ev, const char *location)
+{
+	struct select_event_context *select_ev = talloc_get_type(ev->additional_data,
+		 					   struct select_event_context);
+	struct timeval tval;
+
+	if (ev->signal_events &&
+	    tevent_common_check_signal(ev)) {
+		return 0;
+	}
+
+	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 select_event_loop_select(select_ev, &tval);
+}
+
+static const struct tevent_ops select_event_ops = {
+	.context_init		= select_event_context_init,
+	.add_fd			= select_event_add_fd,
+	.set_fd_close_fn	= tevent_common_fd_set_close_fn,
+	.get_fd_flags		= tevent_common_fd_get_flags,
+	.set_fd_flags		= tevent_common_fd_set_flags,
+	.add_timer		= tevent_common_add_timer_v2,
+	.schedule_immediate	= tevent_common_schedule_immediate,
+	.add_signal		= tevent_common_add_signal,
+	.loop_once		= select_event_loop_once,
+	.loop_wait		= tevent_common_loop_wait,
+};
+
+_PRIVATE_ bool tevent_select_init(void)
+{
+	return tevent_register_backend("select", &select_event_ops);
+}