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<a name="The.afm-system-daemon"></a>
<h1>The afm-system-daemon</h1>

<pre><code>version: 1
Date:    30 mai 2016
Author:  José Bollo
</code></pre>

<p><ul>
 <li><a href="#The.afm-system-daemon">The afm-system-daemon</a>
 <ul>
  <li><a href="#Foreword">Foreword</a></li>
  <li><a href="#Introduction">Introduction</a></li>
  <li><a href="#Starting..strong.afm-system-daemon..strong.">Starting <strong>afm-system-daemon</strong></a></li>
  <li><a href="#The.D-Bus.interface">The D-Bus interface</a>
  <ul>
   <li><a href="#Overview.of.the.dbus.interface">Overview of the dbus interface</a></li>
   <li><a href="#The.protocol.over.D-Bus">The protocol over D-Bus</a>
   <ul>
    <li><a href="#Method.org.AGL.afm.system.install">Method org.AGL.afm.system.install</a></li>
    <li><a href="#Method.org.AGL.afm.system.uninstall">Method org.AGL.afm.system.uninstall</a></li>
   </ul>
   </li>
  </ul>
  </li>
 </ul>
 </li>
</ul></p>

<a name="Foreword"></a>
<h2>Foreword</h2>

<p>This document describes application framework system daemon fundamentals.
FCF (Fully Conform to Specification) implementation is still under development.
It may happen that current implementation somehow diverges with specifications.</p>

<a name="Introduction"></a>
<h2>Introduction</h2>

<p>The daemon <strong>afm-system-daemon</strong> is in charge of installing
applications on AGL system. Its main tasks are:</p>

<ul>
<li><p>installs applications and setup security framework
for newly installed application.</p></li>
<li><p>uninstall applications</p></li>
</ul>


<p>The <strong>afm-system-daemon</strong> takes its orders from system
instance of D-Bus.</p>

<p>The figure below summarizes the situation of <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 serialization 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 implementation
returns a dbus error that is a string.</p>

<p>Here is an example using <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 a widget file.</p>

<p>When an application with the same <em>id</em> and <em>version</em> already exists. Outside of
using <em>force=true</em> the application is not reinstalled.</p>

<p>Applications are installed the subdirectories of applications common directory.
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 method of
<strong><em>org.AGL.afm.system.install</em></strong> from <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 a 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, optionally,
a flag to <em>force</em> reinstallation, and, optionally, 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>&ldquo;wgt&rdquo; and &ldquo;root&rdquo; must be absolute paths.</p>

<p><strong>output</strong>: An object with the field &ldquo;added&rdquo; 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 method accessor of
<strong><em>org.AGL.afm.system.uninstall</em></strong> from <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 a signal <strong><em>org.AGL.afm.system.changed</em></strong>.</p>

<p><strong>Input</strong>: the <em>id</em> of the application and optionally the application <em>root</em> path.</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 &lsquo;true&rsquo;.</p>
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