denshooter/genode
1
0
Fork 0
mirror of https://github.com/mmueller41/genode.git synced 2026-01-21 12:32:56 +01:00
Code Issues Packages Projects Releases Wiki Activity

Simpify startup of dynamically linked binaries

Browse Source 
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
This commit is contained in:
Norman Feske
2016-12-22 15:01:19 +01:00
parent 8d521036fb
commit 4da52517c1
112 changed files with 366 additions and 369 deletions
Download Patch File Download Diff File Expand all files Collapse all files

13
repos/ports/mk/gnu_build.mk
View File

@@ -30,7 +30,7 @@
TARGET ?= $(lastword $(subst /, ,$(PRG_DIR)))
PKG ?= $(TARGET)
LIBS += libc libm
LIBS += posix
PWD = $(shell pwd)
@@ -107,18 +107,9 @@ CXXFLAGS += $(COMMON_CFLAGS_CXXFLAGS)
# Unfortunately, the use of '--start-group' and '--end-group' does not suffice
# in all cases because 'libtool' strips those arguments from the 'LIBS' variable.
#
# Furthermore, 'libtool' reorders library names on the command line in a way that
# shared libraries appear before static libraries. This has the unfortunate effect
# that the program's entry symbol 'Genode::component_entry_point' in the static
# library 'component_entry_point.lib.a' is not found anymore. Passing the static
# library names as linker arguments (-Wl,...) works around this problem, because
# 'libtool' keeps command line arguments before the shared library names.
#
LDLIBS_A = $(filter %.a, $(sort $(LINK_ITEMS)) $(EXT_OBJECTS) $(LIBGCC))
LDLIBS_SO = $(filter %.so,$(sort $(LINK_ITEMS)) $(EXT_OBJECTS) $(LIBGCC))
comma := ,
LDLIBS += $(addprefix -Wl$(comma),$(LDLIBS_A)) $(LDLIBS_SO) $(LDLIBS_A)
LDLIBS += $(LDLIBS_A) $(LDLIBS_SO) $(LDLIBS_A)
#
# Re-configure the Makefile if the Genode build environment changes