David Herrmann
99da30059f
By using:
<deny send_destination="org.freedesktop.ModemManager1"/>
..we prevent anyone on the system from sending us signals, even if we
subscribed to them. This is clearly not what this line intended. More
importantly, we silently break mm-auth-provider-polkit, as we never
receiver 'changed' signals via PolkitAuthority. Right now, this is not
required by the implementation of PolkitAuthority, but ModemManager
should not place restrictions on the implementation of external
libraries.
So make sure we only prevent Method-Calls to be sent to us. Any other
message that we didn't expect is automatically discarded by gdbus,
anyway.
Without this change, debugging dbus policies constantly shows messages
that Polkit couldn't send the 'changed' signal to ModemManager. This is
suppressed in non-debugging mode. But it would make debugging a lot
easier, if we'd avoid force-dropping those events and not clutter the
debug-log.
ModemManager. ModemManager provides a unified high level API for communicating with mobile broadband modems, regardless of the protocol used to communicate with the actual device (Generic AT, vendor-specific AT, QCDM, QMI, MBIM...). Using. ModemManager is a system daemon and is not meant to be used directly from the command line. However, since it provides a DBus API, it is possible to use 'dbus-send' commands or the new 'mmcli' command line interface to control it from the terminal. The devices are queried from udev and automatically updated based on hardware events, although a manual re-scan can also be requested to look for RS232 modems. Implementation. ModemManager is a DBus system bus activated service (meaning it's started automatically when a request arrives). It is written in C, using glib and gio. Several GInterfaces specify different features that the modems support, including the generic MMIfaceModem3gpp and MMIfaceModemCdma which provice basic operations for 3GPP (GSM, UMTS, LTE) or CDMA (CDMA1x, EV-DO) modems. If a given feature is not available in the modem, the specific interface will not be exported in DBus. Plugins. Plugins are loaded on startup, and must implement the MMPlugin interface. It consists of a couple of methods which tell the daemon whether the plugin supports a port and to create custom MMBroadbandModem implementations. It most likely makes sense to derive custom modem implementations from one of the generic classes and just add (or override) operations which are not standard. There are multiple fully working plugins in the plugins/ directory that can be used as an example for writing new plugins. Writing new plugins is highly encouraged! The plugin API is open for changes, so if you're writing a plugin and need to add or change some public method, feel free to suggest it! License. The ModemManager and mmcli binaries are both GPLv2+. The libmm-glib library is LGPLv2+.