genode/repos/base/lib/mk
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
..
spec Disambiguate kernel-specific file names 2016-12-23 16:51:32 +01:00
base-common.inc Remove blocking calls from root and parent RPCs 2016-11-25 16:06:42 +01:00
base.inc Build dynamically linked executables by default 2016-12-14 11:22:27 +01:00
base.mk Build dynamically linked executables by default 2016-12-14 11:22:27 +01:00
cxx.mk Clean ldso from using deprecated APIs 2016-11-08 15:26:32 +01:00
ld-platform.inc Simpify startup of dynamically linked binaries 2017-01-13 13:06:52 +01:00
ld.mk ld: generate symbol map from base/lib/symbols/ld 2016-12-23 16:53:17 +01:00
ldso-startup.mk ldso-startup: support build from non-base repos 2016-07-15 11:38:27 +02:00
platform.mk Simpify startup of dynamically linked binaries 2017-01-13 13:06:52 +01:00
README Move repositories to 'repos/' subdirectory 2014-05-14 16:08:00 +02:00
startup.inc Simpify startup of dynamically linked binaries 2017-01-13 13:06:52 +01:00
syscall.mk Move repositories to 'repos/' subdirectory 2014-05-14 16:08:00 +02:00

This directory contains library description files.  Each '<libname>.mk' file
holds the instruction for building the library '<libname>'. These makefiles are
never used directly but they are called from the build system when required.
When called, the build system passes the following variables:

:'BASE_DIR': This is the base directory of the source tree.

Source codes are specified by setting the 'SRC_CC' and 'SRC_C' variables.
The source code locations must be specified via 'vpath'.
A library can include other libraries by setting the 'LIBS'
variable.

Each '<libname>.mk' file must include the 'lib.mk' role file:

! include $(BASE_DIR)/mk/lib.mk

Libraries implementing one and the same library interface may have specific
implementations for different platforms. Such platform-specific '<libname>.mk'
files should be placed into corresponding subdirectories. For example, the
'linux'-specific implementation of the 'server' library resides in the 'linux/'
subdirectory. The build system automatically searches the right '<libname>.mk'
file by evaluating the 'SPECS' configuration variable. If 'SPECS' is set to
'host linux', the build system will look into the directories './', './host',
and './linux'.