Norman Feske 4da52517c1 Simpify startup of dynamically linked binaries
This patch removes the component_entry_point library, which used to
proved a hook for the libc to intercept the call of the
'Component::construct' function. The mechansim has several shortcomings
(see the discussion in the associated issue) and was complex. So we
eventually discarded the approach in favor of the explicit handling of
the startup.

A regular Genode component provides a 'Component::construct' function,
which is determined by the dynamic linker via a symbol lookup.
For the time being, the dynamic linker falls back to looking up a 'main'
function if no 'Component::construct' function could be found.

The libc provides an implementation of 'Component::construct', which
sets up the libc's task handling and finally call the function
'Libc::Component::construct' from the context of the appllication task.
This function is expected to be provided by the libc-using application.
Consequently, Genode components that use the libc have to implement the
'Libc::Component::construct' function.

The new 'posix' library provides an implementation of
'Libc::Component::construct' that calls a main function. Hence, POSIX
programs that merely use the POSIX API merely have to add 'posix' to the
'LIBS' declaration in their 'target.mk' file. Their execution starts at
'main'.

Issue #2199
2017-01-13 13:06:52 +01:00
..
2015-06-22 14:43:34 +02:00

This is the example operating system based on the Genode OS framework:

:_Init_: is the first real process in the system. The provided implementation
  uses a very simple XML parser to read its configuration files.

:_Drivers_: The example OS has basic drivers for frame buffer, mouse and
  keyboard input, the PCI bus, the real-time clock, and system-specific timers.

:_Server_: The only server in the example OS is Nitpicker, a
  minimal-complexity GUI server.

:_Test_: are also part of the example OS. You may have a look at the fork
  bomb as a simple system stress test.

:_Ldso_: is the dynamic linker used for loading executables that are linked
  against shared libraries.

:_Lib_: contains libraries used by the components of the OS repository,
  for example, the alarm framework.