genode

History

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
..
doc	tool: remove deprecated 'make prepare' mechanism	2016-03-17 17:02:04 +01:00
include	Simpify startup of dynamically linked binaries	2017-01-13 13:06:52 +01:00
lib	Simpify startup of dynamically linked binaries	2017-01-13 13:06:52 +01:00
ports	qt5: fix download link	2016-12-23 16:52:10 +01:00
run	Simpify startup of dynamically linked binaries	2017-01-13 13:06:52 +01:00
src	Simpify startup of dynamically linked binaries	2017-01-13 13:06:52 +01:00
README	README update	2016-08-30 17:24:00 +02:00

README

This directory contains ports of popular 3rd-party software to Genode.


Usage
-----

The tool './tool/ports/prepare_port' in the toplevel directory automates the
task of downloading and preparing the library source codes. You can select
individual packages that have to be prepared by specifying their base names
(without the version number) as command-line argument. For example, the
following command prepares both the C library and the Freetype library:
! ./tool/ports/prepare_port libc freetype

To compile and link against 3rd-party libraries of the 'libports' repository,
you have to include the repository into the build process by appending it to the
'REPOSITORIES' declaration of your '<build-dir>/etc/build.conf' file.


Under the hood
--------------

For each library, there is a file contained in the 'libports/ports/'
subdirectory. The file is named after the library and contains the
library-specific rules for downloading the source code and installing header
files.


How does 'libports' relate to the other repositories?
-----------------------------------------------------

Most libraries hosted in the 'libports' repository expect a complete C library,
which is provided with the 'libc' package. Please do not forget to prepare the
libc package when using any of the other libports packages. The libc, in turn,
depends on the 'os' repository for its back end. Because the 'os' repository is
the home of the dynamic linker, libraries contained in 'libports' are safe to
assume the presence of the dynamic linker and, thus, should be built as shared
libraries.