unix-fd: add message encoding/decoding for unix fds

When appending unix fds to the message a new entry in the fd array will
be allocated and the index to it will be written to the message payload.

When parsing unix fds from the message the index will be read from the
payload and then looked up in the fd array.

When we read fds we put them in a queue first. Since each message knows
how many fds are attached to it we will then pop enough fds from this
queue each time we decode a message from the stream.

This should make sending and receiving more portable since we don't make
any strong requirements on the exact semantics of the SCM_RIGHTS
implementation: as long as fds are recieved in order, none or lost and
the arrive at the same time as at least one byte from the actual message
dat we should be able to handle them correctly.

1 files changed, 15 insertions, 0 deletions

diff --git a/dbus/dbus-message-internal.h b/dbus/dbus-message-internal.h
index 2e995b47..032268f1 100644
--- a/dbus/dbus-message-internal.h
+++ b/dbus/dbus-message-internal.h
@@ -34,6 +34,9 @@ typedef struct DBusMessageLoader DBusMessageLoader;
 void _dbus_message_get_network_data  (DBusMessage       *message,
 				      const DBusString **header,
 				      const DBusString **body);
+void _dbus_message_get_unix_fds      (DBusMessage *messgage,
+                                      const int **fds,
+                                      unsigned *n_fds);
 
 void        _dbus_message_lock                  (DBusMessage  *message);
 void        _dbus_message_unlock                (DBusMessage  *message);
@@ -54,6 +57,14 @@ void               _dbus_message_loader_get_buffer            (DBusMessageLoader
 void               _dbus_message_loader_return_buffer         (DBusMessageLoader  *loader,
                                                                DBusString         *buffer,
                                                                int                 bytes_read);
+
+dbus_bool_t        _dbus_message_loader_get_unix_fds          (DBusMessageLoader  *loader,
+                                                               int               **fds,
+                                                               unsigned           *max_n_fds);
+void               _dbus_message_loader_return_unix_fds       (DBusMessageLoader  *loader,
+                                                               int                *fds,
+                                                               unsigned            n_fds);
+
 dbus_bool_t        _dbus_message_loader_queue_messages        (DBusMessageLoader  *loader);
 DBusMessage*       _dbus_message_loader_peek_message          (DBusMessageLoader  *loader);
 DBusMessage*       _dbus_message_loader_pop_message           (DBusMessageLoader  *loader);
@@ -67,6 +78,10 @@ void               _dbus_message_loader_set_max_message_size  (DBusMessageLoader
                                                                long                size);
 long               _dbus_message_loader_get_max_message_size  (DBusMessageLoader  *loader);
 
+void               _dbus_message_loader_set_max_message_unix_fds(DBusMessageLoader  *loader,
+                                                                 long                n);
+long               _dbus_message_loader_get_max_message_unix_fds(DBusMessageLoader  *loader);
+
 DBUS_END_DECLS
 
 #endif /* DBUS_MESSAGE_INTERNAL_H */