tevent: split out tevent_common_invoke_fd_handler()

We'll undo the 0.9.36 ABI change on the 0.9.37 release
at the end of this patchset.

Signed-off-by: Stefan Metzmacher <metze@samba.org>
Reviewed-by: Ralph Boehme <slow@samba.org>

6 files changed, 47 insertions, 6 deletions

diff --git a/lib/tevent/ABI/tevent-0.9.36.sigs b/lib/tevent/ABI/tevent-0.9.36.sigs
index 451e380688c..443bb7cb6c9 100644
--- a/lib/tevent/ABI/tevent-0.9.36.sigs
+++ b/lib/tevent/ABI/tevent-0.9.36.sigs
@@ -32,6 +32,7 @@ tevent_common_fd_get_flags: uint16_t (struct tevent_fd *)
 tevent_common_fd_set_close_fn: void (struct tevent_fd *, tevent_fd_close_fn_t)
 tevent_common_fd_set_flags: void (struct tevent_fd *, uint16_t)
 tevent_common_have_events: bool (struct tevent_context *)
+tevent_common_invoke_fd_handler: int (struct tevent_fd *, uint16_t, bool *)
 tevent_common_invoke_immediate_handler: int (struct tevent_immediate *, bool *)
 tevent_common_invoke_signal_handler: int (struct tevent_signal *, int, int, void *, bool *)
 tevent_common_invoke_timer_handler: int (struct tevent_timer *, struct timeval, bool *)
diff --git a/lib/tevent/tevent_epoll.c b/lib/tevent/tevent_epoll.c
index 4147c67af2a..5f7ef5d83d1 100644
--- a/lib/tevent/tevent_epoll.c
+++ b/lib/tevent/tevent_epoll.c
@@ -725,8 +725,7 @@ static int epoll_event_loop(struct epoll_event_context *epoll_ev, struct timeval
 		 */
 		flags &= fde->flags;
 		if (flags) {
-			fde->handler(epoll_ev->ev, fde, flags, fde->private_data);
-			break;
+			return tevent_common_invoke_fd_handler(fde, flags, NULL);
 		}
 	}
 
diff --git a/lib/tevent/tevent_fd.c b/lib/tevent/tevent_fd.c
index f33ae841b39..7859cbb00ef 100644
--- a/lib/tevent/tevent_fd.c
+++ b/lib/tevent/tevent_fd.c
@@ -30,6 +30,12 @@
 
 int tevent_common_fd_destructor(struct tevent_fd *fde)
 {
+	if (fde->destroyed) {
+		tevent_common_check_double_free(fde, "tevent_fd double free");
+		goto done;
+	}
+	fde->destroyed = true;
+
 	if (fde->event_ctx) {
 		DLIST_REMOVE(fde->event_ctx->fd_events, fde);
 	}
@@ -37,6 +43,13 @@ int tevent_common_fd_destructor(struct tevent_fd *fde)
 	if (fde->close_fn) {
 		fde->close_fn(fde->event_ctx, fde, fde->fd, fde->private_data);
 		fde->fd = -1;
+		fde->close_fn = NULL;
+	}
+
+	fde->event_ctx = NULL;
+done:
+	if (fde->busy) {
+		return -1;
 	}
 
 	return 0;
@@ -92,3 +105,29 @@ void tevent_common_fd_set_close_fn(struct tevent_fd *fde,
 {
 	fde->close_fn = close_fn;
 }
+
+int tevent_common_invoke_fd_handler(struct tevent_fd *fde, uint16_t flags,
+				    bool *removed)
+{
+	if (removed != NULL) {
+		*removed = false;
+	}
+
+	if (fde->event_ctx == NULL) {
+		return 0;
+	}
+
+	fde->busy = true;
+	fde->handler(fde->event_ctx, fde, flags, fde->private_data);
+	fde->busy = false;
+
+	if (fde->destroyed) {
+		talloc_set_destructor(fde, NULL);
+		TALLOC_FREE(fde);
+		if (removed != NULL) {
+			*removed = true;
+		}
+	}
+
+	return 0;
+}
diff --git a/lib/tevent/tevent_internal.h b/lib/tevent/tevent_internal.h
index d74684c72c2..1183b9f7f83 100644
--- a/lib/tevent/tevent_internal.h
+++ b/lib/tevent/tevent_internal.h
@@ -170,6 +170,8 @@ struct tevent_req {
 struct tevent_fd {
 	struct tevent_fd *prev, *next;
 	struct tevent_context *event_ctx;
+	bool busy;
+	bool destroyed;
 	int fd;
 	uint16_t flags; /* see TEVENT_FD_* flags */
 	tevent_fd_handler_t handler;
@@ -343,6 +345,8 @@ void tevent_common_fd_set_close_fn(struct tevent_fd *fde,
 				   tevent_fd_close_fn_t close_fn);
 uint16_t tevent_common_fd_get_flags(struct tevent_fd *fde);
 void tevent_common_fd_set_flags(struct tevent_fd *fde, uint16_t flags);
+int tevent_common_invoke_fd_handler(struct tevent_fd *fde, uint16_t flags,
+				    bool *removed);
 
 struct tevent_timer *tevent_common_add_timer(struct tevent_context *ev,
 					     TALLOC_CTX *mem_ctx,
diff --git a/lib/tevent/tevent_poll.c b/lib/tevent/tevent_poll.c
index 282f3cf3082..74c418ca421 100644
--- a/lib/tevent/tevent_poll.c
+++ b/lib/tevent/tevent_poll.c
@@ -565,8 +565,7 @@ static int poll_event_loop_poll(struct tevent_context *ev,
 		flags &= fde->flags;
 		if (flags != 0) {
 			DLIST_DEMOTE(ev->fd_events, fde);
-			fde->handler(ev, fde, flags, fde->private_data);
-			return 0;
+			return tevent_common_invoke_fd_handler(fde, flags, NULL);
 		}
 	}
 
diff --git a/lib/tevent/tevent_port.c b/lib/tevent/tevent_port.c
index 8cf9fd1a0de..e91d442389d 100644
--- a/lib/tevent/tevent_port.c
+++ b/lib/tevent/tevent_port.c
@@ -600,8 +600,7 @@ static int port_event_loop(struct port_event_context *port_ev, struct timeval *t
 		 */
 		flags &= fde->flags;
 		if (flags) {
-			fde->handler(ev, fde, flags, fde->private_data);
-			break;
+			return tevent_common_invoke_fd_handler(fde, flags, NULL);
 		}
 	}