To Control your System
Free
To Control your System
Free
66-dbus-launch is a tool for launching, supervising, and reacting to dbus-broker events emitted by relevant D-Bus signals.
66-dbus-launch [ -h ] [ -z ] [ -v verbosity ] [ -d notif ]66-dbus-launch acts as a launcher for the dbus-broker, spawning and managing a D-Bus Message Bus.
On receiving D-Bus or kernel signals, the launcher executes tasks based on the signal received(see Execution tasks). Each instance of 66-dbus-launch manages exactly one message bus. Each message bus is independent.
When started by a regular user, 66-dbus-launch will drop privileges before executing dbus-broker. The launcher only manages services and environments for the process owner, meaning a user launcher cannot manage root services or environments and vice versa.
This program is only built if the --enable-dbus= option is passed during compilation (see Build Requirements).
This tool is inspired by the dbus-controllers project and the original dbus-broker program.
-h : prints this help.
-z : enable color. If 66-dbus-launch is not launched from a terminal, the color is automatically disabled and the option has no effect.
-v verbosity: increases/decreases the verbosity of the command.
-d notif : notify readiness on file descriptor notif. Has no effect when launched from a terminal. Notification occurs before entering the loop, ensuring that both the broker and launcher are fully synchronized.
At startup, 66-dbus-launch performs the following tasks:
Creates, binds, and listens to a socket at /run/dbus/system_bus_socket or /run/user/UID/bus, depending on the process owner. The socket name can be customized at compile time with --with-dbus-system-name=NAME and --with-dbus-session-name=NAME.
Sets the DBUS_SYSTEM_BUS_ADDRESS=unix:path=/run/dbus/system_bus_socket and DBUS_SESSION_BUS_ADDRESS=unix:path=/run/user/UID/bus environment variables according to the owner of the process.
For each D-Bus service file found in /usr/share/dbus-1/system-services or /usr/share/dbus-1/services, it reads, parses, translates, and writes a corresponding 66 frontend file. An example:
[Main]
Type = classic
Description "org.freedesktop.Consolekit.dbus dbus service"
User = ( root )
Version = 0.0.1
InTree = dbus
MaxDeath = 5
TimeoutStart = 3000
TimeoutStop = 3000
[Start]
Execute = (
execl-envfile -l ${ImportFile}
/usr/bin/console-kit-daemon --nodaemon
)
[Environment]
ImportFile=/etc/66/environment/0000-dbusIt ensures that you use the latest D-Bus file declarations by overwriting any existing frontend files with the same name.
Creates an unbound socket pair and forks the command /usr/bin/dbus-broker --controller FD --machine-id MachineId, with FD being the file descriptor of the connected socket's standard input. If /etc/machine-id is unreadable, it defaults to 00000000000000000000000000000001. For regular users, privileges are dropped before execution.
Notifies readiness (if -d is used) and enters a loop, listening and supervising the broker.
66-dbus-launch responds to kernel signals. A SIGHUP signal triggers a reading, parsing, translating and writting process.
Synchronization of services can also be manually triggered via 66 reload dbus or 66 signal -s HUP dbus.
It also synchronizes the available list of services between the launcher and the broke as follows:
- If a D-Bus service file is removed, the launcher deactivates from the broker, executes 66 remove <service>, and erases the corresponding 66 frontend file.
- If a new D-Bus service is found, the launcher triggers the reading, parsing, translating and writting process, and activates the service in the broker.
- For an existing service with the same name, the launcher executes 66 parse -f <service> to ensure the latest D-Bus service declaration is used. Note that the service need to restarted for any changes to take effect.
66-dbus-launch reacts on D-Bus signals:
66 start <service> command.A org.freedesktop.DBus.UpdateActivationEnvironment() request trigger the update environment variables, writing them by default to /etc/66/environment/0000-dbus or $HOME/.66/environment/0000-dbus, depending on ownership. The file is overwritten for each update. You can also use the dbus-update-activation-environment program to trigger this update. Note that you may need to define the DBUS_SESSION_BUS_ADDRESS before launching the dbus-update-activation-environment program. For root, use DBUS_SESSION_BUS_ADDRESS=unix:path=/run/dbus/system_bus_socket, and for regular user, use DBUS_SESSION_BUS_ADDRESS=unix:path=/run/user/UID/bus.
A org.freedesktop.DBus.ReloadConfig() request triggers the same process as a SIGHUP signal.
Stopping the launcher invokes a 66 tree free dbus command, as each service frontend file declares InTree=dbus.
As the frontend file of each service declare InTree=dbus, stopping the launcher invoke a 66 tree free dbus command. This behavior may change in the future. For now, this reduce the surface of attack and guarantee you to always use a fresh installation of the service.
The following frontend file can be used to start a 66-dbus-launch daemon, either as root or as a regular user, by setting User=(root) or User=(user) in the example below:
[Main]
Type=classic
Description="Dbus-broker launcher for @U account"
User=(root)
Version=0.0.1
TimeoutStart=3000
TimeoutStop=3000
MaxDeath=5
Notify=3
[Start]
Execute=(66-dbus-launch -d3 -v${Verbosity})
[Environment]
Verbosity=!3By default, the frontend file can be installed at /usr/share/66/service (for root) and /usr/share/66/service/user (for regular users).
The --enable-dbus= option is required at compile time, with either basu or elogind as the provider of sd_bus functions. The use of the sd_bus library may change at any time without warning.
For the runtime, the system must have dbus-broker installed for 66-dbus-launch to function properly.
dbus-broker's policy API isn't yet stable, allowing broad access for now.
Currently, 66-dbus-launch doesn't handle configuration files for D-Bus (e.g., /usr/share/dbus-1/{system,session}.conf).