io: catch double registration and unregistration bugs

Signed-off-by: Patrick McHardy <kaber@trash.net>

2 files changed, 25 insertions, 7 deletions

diff --git a/include/io.h b/include/io.h
index 5aaea18..5d8c289 100644
--- a/include/io.h
+++ b/include/io.h
@@ -10,20 +10,27 @@
 #include <sys/socket.h>
 #include <utils.h>
 
+enum dect_fd_state {
+	DECT_FD_UNREGISTERED,
+	DECT_FD_REGISTERED,
+};
+
 /**
  * struct dect_fd - libdect file descriptor
  *
  * @callback:		callback to invoke for events
  * @fd:			file descriptor numer
+ * @state:		file descriptor registration state (debugging)
  * @data:		libdect internal data
  * @priv:		libdect user private file-descriptor storage
  */
 struct dect_fd {
-	void		(*callback)(struct dect_handle *,
-				    struct dect_fd *, uint32_t);
-	int		fd;
-	void		*data;
-	uint8_t		priv[] __aligned(__alignof__(uint64_t));
+	void			(*callback)(struct dect_handle *,
+					    struct dect_fd *, uint32_t);
+	int			fd;
+	enum dect_fd_state	state;
+	void			*data;
+	uint8_t			priv[] __aligned(__alignof__(uint64_t));
 };
 
 extern struct dect_fd *dect_alloc_fd(const struct dect_handle *dh);
diff --git a/src/io.c b/src/io.c
index 9c6705f..ff1b200 100644
--- a/src/io.c
+++ b/src/io.c
@@ -57,7 +57,8 @@ struct dect_fd *dect_alloc_fd(const struct dect_handle *dh)
 			  dh->ops->event_ops->fd_priv_size);
 	if (dfd == NULL)
 		return NULL;
-	dfd->fd = -1;
+	dfd->fd    = -1;
+	dfd->state = DECT_FD_UNREGISTERED;
 	return dfd;
 }
 EXPORT_SYMBOL(dect_alloc_fd);
@@ -96,13 +97,21 @@ EXPORT_SYMBOL(dect_setup_fd);
 int dect_register_fd(const struct dect_handle *dh, struct dect_fd *dfd,
 		     uint32_t events)
 {
-	return dh->ops->event_ops->register_fd(dh, dfd, events);
+	int err;
+
+	assert(dfd->state == DECT_FD_UNREGISTERED);
+	err = dh->ops->event_ops->register_fd(dh, dfd, events);
+	if (err == 0)
+		dfd->state = DECT_FD_REGISTERED;
+	return err;
 }
 EXPORT_SYMBOL(dect_register_fd);
 
 void dect_unregister_fd(const struct dect_handle *dh, struct dect_fd *dfd)
 {
+	assert(dfd->state == DECT_FD_REGISTERED);
 	dh->ops->event_ops->unregister_fd(dh, dfd);
+	dfd->state = DECT_FD_UNREGISTERED;
 }
 EXPORT_SYMBOL(dect_unregister_fd);
 
@@ -118,12 +127,14 @@ EXPORT_SYMBOL(dect_unregister_fd);
  */
 void dect_handle_fd(struct dect_handle *dh, struct dect_fd *dfd, uint32_t events)
 {
+	assert(dfd->state == DECT_FD_REGISTERED);
 	dfd->callback(dh, dfd, events);
 }
 EXPORT_SYMBOL(dect_handle_fd);
 
 void dect_close(const struct dect_handle *dh, struct dect_fd *dfd)
 {
+	assert(dfd->state == DECT_FD_UNREGISTERED);
 	if (dfd->fd >= 0)
 		close(dfd->fd);
 	dect_free(dh, dfd);