Changes: Stuff to the README added.

README

@@ -1,3 +1,72 @@
-!! Add a short and generic description here !!
+What is applauncherd?
+==============================
+
+Applauncherd is a daemon that helps to launch applications faster by
+preloading dynamically linked libraries and caching stuff (MComponentCache). It also saves memory, because all launched
+applications share certain resources.
+
+Applauncherd also provides support for a splash screen and fast single
+instance launches.
+
+Some technical details are explained below. 
+
+Install applauncherd-doc for the Doxygen-based user documentation.
+See INSTALL on how to build applauncherd and the documentation.
+
+Technical overview
+==============================
+
+The applauncherd daemon is started by UpStart as part of XSession, that
+is, at the same level as the desktop (MeeGo Touch homescreen).
+Applauncherd forks the will-be-application process, "booster", before
+knowing which application is going to be launched next. There can be
+different kinds of boosters optimized for different kinds of
+applications, e.g. Qt, Meego Touch, QML. 
+
+In the current architecture boosters are loaded as plugins. Applauncherd
+searches for plugin libraries in /usr/lib/applaucherd/lib*booster.so and
+forks a new process for each booster to wait for launch commands from the
+user.
+
+The user uses the launcher always through a special invoker program. The
+invoker (/usr/bin/invoker) tells booster process to load an application
+binary via a socket connection. 
+
+The application to be launched via applauncherd should be compiled as a
+shared library or a position independent executable (-pie) and it should
+always export main(). There's also a "booster" for all applications to
+be used with the splash screen. In that case exec() is used.
+
+Technical details
+==============================
+
+Before loading, booster process changes its security credentials so that
+the code in the application binary will be executed with the correct credentials. Loading the binary is done with dlopen(), and therefore the
+application needs to be compiled and linked as a shared library or a
+position independent executable. The booster process also sets the
+environment variables. Finally, it finds the main function in the
+application binary with dlsym() and calls the main() with the command
+line arguments given by the invoker. 
+
+The launcher itself is a library that is loaded by a small C-program (/usr/bin/applauncherd.bin). Idea behind this is to avoid linking the
+launcher binary to any libraries. This allows us to fully control how
+(with which flags) the preloaded libraries are opened with dlopen(). 
+
+Aegis platform security is used to protect the socket connection between
+invoker and launcher. Currently this works only on the target device. It
+is automatically disabled by the build scripts when compiling on x86. 
+
+Each application type (currently Qt and MeeGo Touch) has its own booster
+process. When booster launches the application by calling the "main()"
+function, applauncherd will create new booster process of that type.
+
+Booster processes do some initializations that cannot be shared among
+other processes and therefore have to be done after forking. This allows,
+for instance, instantiating a MeeGo Touch application before knowing the
+name of the application. Then the booster process waits for a connection
+from the invoker with the information about which application should be
+launched. 
+
+With MeeGo Touch booster it's possible to fetch certain objects from a cache. This will significantly reduce the startup time of an application. 
 
 

debian/changelog

@@ -1,9 +1,10 @@
 applauncherd (0.28.0) unstable; urgency=low
 
+  * Changes: Stuff to the README added.
   * Changes: Some coverity tool defects are fixed
   * Changes: Coverity tool defect fixes for tests
 
- -- Olli Leppanen <olli.leppanen@nokia.com>  Thu, 14 Apr 2011 13:49:24 +0300
+ -- Jussi Lind <jussi.lind@nokia.com>  Thu, 14 Apr 2011 15:44:45 +0300
 
 applauncherd (0.27.0) stable; urgency=low