version: 1
Date: 29 mai 2016
Author: José Bollo
This document describes what we intend to do. It may happen that our current implementation and the content of this document differ.
In case of differences, it is assumed that this document is right and the implementation is wrong.
The daemon afm-system-daemon is in charge of installing applications on the system. Its main tasks are:
installs the applications and setup the security framework to include it
uninstall the applications
The afm-system-daemon takes its orders from the system instance of D-Bus.
The figure below summarizes the situation of the afm-system-daemon in the system.
+------------------------------------------------------------+
| User |
| |
| +-------------------------------------------------+ |
| | | |
| | afm-user-daemon | |
| | | |
| +----------+----------------------+----------+----+ |
| | | : |
| | | : |
:================|======================|==========:=========:
| | | : |
| +----------+----------+ +-----+-----+ : |
| | D-Bus system +-----+ CYNARA | : |
| +----------+----------+ +-----+-----+ : |
| | | : |
| +----------+---------+ +-------+----------+----+ |
| | afm-system-daemon +----+ SECURITY-MANAGER | |
| +--------------------+ +-----------------------+ |
| |
| System |
+------------------------------------------------------------+
afm-system-daemon is launched as a systemd service attached to system. Normally, the service file is located at /lib/systemd/system/afm-system-daemon.service.
The options for launching afm-system-daemon are:
-r
--root directory
Set the root application directory.
Note that the default root directory is defined
to be /usr/share/afm/applications (may change).
-d
--daemon
Daemonizes the process. It is not needed by sytemd.
-q
--quiet
Reduces the verbosity (can be repeated).
-v
--verbose
Increases the verbosity (can be repeated).
-h
--help
Prints a short help.
afm-system-daemon takes its orders from the session instance of D-Bus. The use of D-Bus is great because it allows to implement discovery and signaling.
The afm-system-daemon is listening with the destination name org.AGL.afm.system at the object of path /org/AGL/afm/system on the interface org.AGL.afm.system for the below detailed members install and uninstall.
D-Bus is mainly used for signaling and discovery. Its optimized typed protocol is not used except for transmitting only one string in both directions.
The client and the service are using JSON serialisation to exchange data.
The D-Bus interface is defined by:
DESTINATION: org.AGL.afm.system
PATH: /org/AGL/afm/system
INTERFACE: org.AGL.afm.system
The signature of any member of the interface is string -> string for JSON -> JSON.
This is the normal case. In case of error, the current implmentation returns a dbus error that is a string.
Here is an example that use dbus-send to query data on installed applications.
dbus-send --session --print-reply \
--dest=org.AGL.afm.system \
/org/AGL/afm/system \
org.AGL.afm.system.install 'string:"/tmp/appli.wgt"'
Description: Install an application from its widget file.
If an application of the same id and version exists, it is not reinstalled except if force=true.
Applications are installed in the subdirectories of the common directory of applications. If root is specified, the application is installed under the sub-directories of the root defined.
Note that this methods is a simple accessor to the method org.AGL.afm.system.install of afm-system-daemon.
After the installation and before returning to the sender, afm-system-daemon sends the signal org.AGL.afm.system.changed.
Input: The path of the widget file to install and, optionaly, a flag to force reinstallation, and, optionaly, a root directory.
Either just a string being the absolute path of the widget file:
"/a/path/driving/to/the/widget"
Or an object:
{
"wgt": "/a/path/to/the/widget",
"force": false,
"root": "/a/path/to/the/root"
}
“wgt” and “root” must be absolute paths.
output: An object with the field “added” being the string for the id of the added application.
{"added":"appli@x.y"}
Description: Uninstall an application from its id.
Note that this methods is a simple accessor to the method org.AGL.afm.system.uninstall of afm-system-daemon.
After the uninstallation and before returning to the sender, afm-system-daemon sends the signal org.AGL.afm.system.changed.
Input: the id of the application and, otpionaly, the path to root of the application.
Either a string:
"appli@x.y"
Or an object:
{
"id": "appli@x.y",
"root": "/a/path/to/the/root"
}
output: the value ‘true’.