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<a name="The.afm-system-daemon"></a>
<h1>The afm-system-daemon</h1>
<pre><code>version: 1
Date: 15 March 2016
Author: José Bollo
</code></pre>
<a name="Foreword"></a>
<h2>Foreword</h2>
<p>This document describes what we intend to do. It may happen that our
current implementation and the content of this document differ.</p>
<p>In case of differences, it is assumed that this document is right
and the implementation is wrong.</p>
<a name="Introduction"></a>
<h2>Introduction</h2>
<p>The daemon <strong>afm-system-daemon</strong> is in charge of installing
applications on the system. Its main tasks are:</p>
<ul>
<li><p>installs the applications and setup the security framework
to include it</p></li>
<li><p>uninstall the applications</p></li>
</ul>
<p>The <strong>afm-system-daemon</strong> takes its orders from the system
instance of D-Bus.</p>
<p>The figure below summarizes the situation of the
<strong>afm-system-daemon</strong> in the system.</p>
<pre><code>+------------------------------------------------------------+
| User |
| |
| +-------------------------------------------------+ |
| | | |
| | afm-user-daemon | |
| | | |
| +----------+----------------------+----------+----+ |
| | | : |
| | | : |
:================|======================|==========:=========:
| | | : |
| +----------+----------+ +-----+-----+ : |
| | D-Bus system +-----+ CYNARA | : |
| +----------+----------+ +-----+-----+ : |
| | | : |
| +----------+---------+ +-------+----------+----+ |
| | afm-system-daemon +----+ SECURITY-MANAGER | |
| +--------------------+ +-----------------------+ |
| |
| System |
+------------------------------------------------------------+
</code></pre>
<a name="Starting..strong.afm-system-daemon..strong."></a>
<h2>Starting <strong>afm-system-daemon</strong></h2>
<p><strong>afm-system-daemon</strong> is launched as a <strong>systemd</strong> service
attached to system. Normally, the service file is
located at /lib/systemd/system/afm-system-daemon.service.</p>
<p>The options for launching <strong>afm-system-daemon</strong> are:</p>
<pre><code>-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.
</code></pre>
<a name="The.D-Bus.interface"></a>
<h2>The D-Bus interface</h2>
<a name="Overview.of.the.dbus.interface"></a>
<h3>Overview of the dbus interface</h3>
<p><strong><em>afm-system-daemon</em></strong> 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.</p>
<p>The <strong>afm-system-daemon</strong> is listening with the destination name
<strong><em>org.AGL.afm.system</em></strong> at the object of path <strong><em>/org/AGL/afm/system</em></strong>
on the interface <strong><em>org.AGL.afm.system</em></strong> for the below detailed
members <strong><em>install</em></strong> and <strong><em>uninstall</em></strong>.</p>
<p>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.</p>
<p>The client and the service are using JSON serialisation to
exchange data.</p>
<p>The D-Bus interface is defined by:</p>
<ul>
<li><p>DESTINATION: <strong>org.AGL.afm.system</strong></p></li>
<li><p>PATH: <strong>/org/AGL/afm/system</strong></p></li>
<li><p>INTERFACE: <strong>org.AGL.afm.system</strong></p></li>
</ul>
<p>The signature of any member of the interface is <strong><em>string -> string</em></strong>
for <strong><em>JSON -> JSON</em></strong>.</p>
<p>This is the normal case. In case of error, the current implmentation
returns a dbus error that is a string.</p>
<p>Here is an example that use <em>dbus-send</em> to query data on
installed applications.</p>
<pre><code>dbus-send --session --print-reply \
--dest=org.AGL.afm.system \
/org/AGL/afm/system \
org.AGL.afm.system.install 'string:"/tmp/appli.wgt"'
</code></pre>
<a name="The.protocol.over.D-Bus"></a>
<h3>The protocol over D-Bus</h3>
<hr />
<a name="Method.org.AGL.afm.system.install"></a>
<h4>Method org.AGL.afm.system.install</h4>
<p><strong>Description</strong>: Install an application from its widget file.</p>
<p>If an application of the same <em>id</em> and <em>version</em> exists, it is not
reinstalled except if <em>force=true</em>.</p>
<p>Applications are installed in the subdirectories of the common directory
of applications.
If <em>root</em> is specified, the application is installed under the
sub-directories of the <em>root</em> defined.</p>
<p>Note that this methods is a simple accessor to the method
<strong><em>org.AGL.afm.system.install</em></strong> of <strong><em>afm-system-daemon</em></strong>.</p>
<p>After the installation and before returning to the sender,
<strong><em>afm-system-daemon</em></strong> sends the signal <strong><em>org.AGL.afm.system.changed</em></strong>.</p>
<p><strong>Input</strong>: The <em>path</em> of the widget file to install and, optionaly,
a flag to <em>force</em> reinstallation, and, optionaly, a <em>root</em> directory.</p>
<p>Either just a string being the absolute path of the widget file:</p>
<pre><code>"/a/path/driving/to/the/widget"
</code></pre>
<p>Or an object:</p>
<pre><code>{
"wgt": "/a/path/to/the/widget",
"force": false,
"root": "/a/path/to/the/root"
}
</code></pre>
<p>“wgt” and “root” must be absolute paths.</p>
<p><strong>output</strong>: An object with the field “added” being the string for
the id of the added application.</p>
<pre><code>{"added":"appli@x.y"}
</code></pre>
<hr />
<a name="Method.org.AGL.afm.system.uninstall"></a>
<h4>Method org.AGL.afm.system.uninstall</h4>
<p><strong>Description</strong>: Uninstall an application from its id.</p>
<p>Note that this methods is a simple accessor to the method
<strong><em>org.AGL.afm.system.uninstall</em></strong> of <strong><em>afm-system-daemon</em></strong>.</p>
<p>After the uninstallation and before returning to the sender,
<strong><em>afm-system-daemon</em></strong> sends the signal <strong><em>org.AGL.afm.system.changed</em></strong>.</p>
<p><strong>Input</strong>: the <em>id</em> of the application and, otpionaly, the path to
<em>root</em> of the application.</p>
<p>Either a string:</p>
<pre><code>"appli@x.y"
</code></pre>
<p>Or an object:</p>
<pre><code>{
"id": "appli@x.y",
"root": "/a/path/to/the/root"
}
</code></pre>
<p><strong>output</strong>: the value ‘true’.</p>
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