1 files changed, 302 insertions, 0 deletions
diff --git a/tevent/tevent_select.c b/tevent/tevent_select.c
new file mode 100644
index 00000000..35c6f785
--- /dev/null
+++ b/tevent/tevent_select.c
@@ -0,0 +1,302 @@
+/* 
+   Unix SMB/CIFS implementation.
+   main select loop and event handling
+   Copyright (C) Andrew Tridgell	2003-2005
+   Copyright (C) Stefan Metzmacher	2005
+   
+   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 SAMBA's default event loop code
+
+*/
+
+#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 event_context *ev;
+
+	/* list of filedescriptor events */
+	struct fd_event *fd_events;
+
+	/* list of timed events */
+	struct timed_event *timed_events;
+
+	/* the maximum file descriptor number in fd_events */
+	int maxfd;
+
+	/* information for exiting from the event loop */
+	int exit_code;
+
+	/* this is incremented when the loop over events causes something which
+	   could change the events yet to be processed */
+	uint32_t destruction_count;
+};
+
+/*
+  create a select_event_context structure.
+*/
+static int select_event_context_init(struct event_context *ev)
+{
+	struct select_event_context *select_ev;
+
+	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 fd_event *fde;
+
+	select_ev->maxfd = 0;
+	for (fde = select_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 fd_event *fde)
+{
+	struct event_context *ev = fde->event_ctx;
+	struct select_event_context *select_ev = talloc_get_type(ev->additional_data,
+							   struct select_event_context);
+
+	if (select_ev->maxfd == fde->fd) {
+		select_ev->maxfd = EVENT_INVALID_MAXFD;
+	}
+
+	DLIST_REMOVE(select_ev->fd_events, fde);
+	select_ev->destruction_count++;
+
+	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 *select_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 select_event_context *select_ev = talloc_get_type(ev->additional_data,
+							   struct select_event_context);
+	struct fd_event *fde;
+
+	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;
+
+	DLIST_ADD(select_ev->fd_events, fde);
+	if (fde->fd > select_ev->maxfd) {
+		select_ev->maxfd = fde->fd;
+	}
+	talloc_set_destructor(fde, select_event_fd_destructor);
+
+	return fde;
+}
+
+
+/*
+  return the fd event flags
+*/
+static uint16_t select_event_get_fd_flags(struct fd_event *fde)
+{
+	return fde->flags;
+}
+
+/*
+  set the fd event flags
+*/
+static void select_event_set_fd_flags(struct fd_event *fde, uint16_t flags)
+{
+	struct event_context *ev;
+	struct select_event_context *select_ev;
+
+	if (fde->flags == flags) return;
+
+	ev = fde->event_ctx;
+	select_ev = talloc_get_type(ev->additional_data, struct select_event_context);
+
+	fde->flags = flags;
+}
+
+/*
+  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 fd_event *fde;
+	int selrtn;
+	uint32_t destruction_count = ++select_ev->destruction_count;
+
+	/* 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->fd_events; fde; fde = fde->next) {
+		if (fde->flags & EVENT_FD_READ) {
+			FD_SET(fde->fd, &r_fds);
+		}
+		if (fde->flags & EVENT_FD_WRITE) {
+			FD_SET(fde->fd, &w_fds);
+		}
+	}
+
+	if (select_ev->ev->num_signal_handlers && 
+	    common_event_check_signal(select_ev->ev)) {
+		return 0;
+	}
+
+	selrtn = select(select_ev->maxfd+1, &r_fds, &w_fds, NULL, tvalp);
+
+	if (selrtn == -1 && errno == EINTR && 
+	    select_ev->ev->num_signal_handlers) {
+		common_event_check_signal(select_ev->ev);
+		return 0;
+	}
+
+	if (selrtn == -1 && 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. */
+		ev_debug(select_ev->ev, EV_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 */
+		common_event_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->fd_events; fde; fde = fde->next) {
+			uint16_t flags = 0;
+
+			if (FD_ISSET(fde->fd, &r_fds)) flags |= EVENT_FD_READ;
+			if (FD_ISSET(fde->fd, &w_fds)) flags |= EVENT_FD_WRITE;
+			if (flags) {
+				fde->handler(select_ev->ev, fde, flags, fde->private_data);
+				if (destruction_count != select_ev->destruction_count) {
+					break;
+				}
+			}
+		}
+	}
+
+	return 0;
+}		
+
+/*
+  do a single event loop using the events defined in ev 
+*/
+static int select_event_loop_once(struct event_context *ev)
+{
+	struct select_event_context *select_ev = talloc_get_type(ev->additional_data,
+		 					   struct select_event_context);
+	struct timeval tval;
+
+	tval = common_event_loop_timer_delay(ev);
+	if (ev_timeval_is_zero(&tval)) {
+		return 0;
+	}
+
+	return select_event_loop_select(select_ev, &tval);
+}
+
+/*
+  return on failure or (with 0) if all fd events are removed
+*/
+static int select_event_loop_wait(struct event_context *ev)
+{
+	struct select_event_context *select_ev = talloc_get_type(ev->additional_data,
+							   struct select_event_context);
+	select_ev->exit_code = 0;
+
+	while (select_ev->fd_events && select_ev->exit_code == 0) {
+		if (select_event_loop_once(ev) != 0) {
+			break;
+		}
+	}
+
+	return select_ev->exit_code;
+}
+
+static const struct event_ops select_event_ops = {
+	.context_init	= select_event_context_init,
+	.add_fd		= select_event_add_fd,
+	.get_fd_flags	= select_event_get_fd_flags,
+	.set_fd_flags	= select_event_set_fd_flags,
+	.add_timed	= common_event_add_timed,
+	.add_signal	= common_event_add_signal,
+	.loop_once	= select_event_loop_once,
+	.loop_wait	= select_event_loop_wait,
+};
+
+bool events_select_init(void)
+{
+	return event_register_backend("select", &select_event_ops);
+}
+