5be1ce6ee1
This patch fixes the following crash when MMIfaceModem::load_current_bands_ready() dereferences a NULL GError pointer, which happens when the novatel-lte plugin fails to load the current bands but does not propagate the error. Thread 0 *CRASHED* ( SIGSEGV @ 0x00000000 ) 0x7f04d6c89c36 [ModemManager] - mm-iface-modem.c:3886 load_current_bands_ready 0x7f04d6942236 [libgio-2.0.so.0.3200.4] - gsimpleasyncresult.c:767 g_simple_async_result_complete 0x7f04d6942338 [libgio-2.0.so.0.3200.4] - gsimpleasyncresult.c:779 complete_in_idle_cb 0x7f04d67fad74 [libglib-2.0.so.0.3200.4] - gmain.c:2539 g_main_context_dispatch 0x7f04d67fb0f7 [libglib-2.0.so.0.3200.4] - gmain.c:3146 g_main_context_iterate 0x7f04d67fb551 [libglib-2.0.so.0.3200.4] - gmain.c:3340 g_main_loop_run 0x7f04d6c68795 [ModemManager] - main.c:142] main 0x7f04d6213464 [libc-2.15.so] - libc-start.c:234] __libc_start_main 0x7f04d6c68318 [ModemManager] + 0x0001d318]
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!