genode/repos/base/src/lib/ldso
Sebastian Sumpf 5a821d4c92 base: Genode's dynamic linker
Issue #1280
2014-11-12 14:44:15 +01:00
..
arm base: Genode's dynamic linker 2014-11-12 14:44:15 +01:00
include base: Genode's dynamic linker 2014-11-12 14:44:15 +01:00
startup base: Genode's dynamic linker 2014-11-12 14:44:15 +01:00
x86_32 base: Genode's dynamic linker 2014-11-12 14:44:15 +01:00
x86_64 base: Genode's dynamic linker 2014-11-12 14:44:15 +01:00
README base: Genode's dynamic linker 2014-11-12 14:44:15 +01:00
file.cc base: Genode's dynamic linker 2014-11-12 14:44:15 +01:00
linker.ld base: Genode's dynamic linker 2014-11-12 14:44:15 +01:00
main.cc base: Genode's dynamic linker 2014-11-12 14:44:15 +01:00
symbol.map base: Genode's dynamic linker 2014-11-12 14:44:15 +01:00
test.cc base: Genode's dynamic linker 2014-11-12 14:44:15 +01:00

README

This directory contains Genode's dynamic linker (ldso)


Usage
-----

To build a shared library instead of a regular static library, you just need to
declare 'SHARED_LIB = yes' in the library-description file.  When doing so, a
'<libname>.lib.so' file will be generated and installed in the
'<build-dir>/bin/' directory.  For building an executable that uses a shared
library, no special precautions are needed. The build system will automatically
detect the use of shared libraries, concludes that the binary must be
dynamically linked, and will use the correct linker script.  When loading a
dynamically linked program, the dynamic linker 'ldso.lib.so' and all used shared
objects must be loaded as well.

The linker can be configured through the '<config>' node when loading a dynamic
binary. Currently there are to configurations options, 'ld_bind_now="yes"'
causes the linker to resolve all symbol references on program loading.
'ld_verbose="yes"' outputs library load informations before starting the
program.

Configuration snippet:

!<!-- bind immediately, no library informations -->
!<start name="dynamic_binary">
!  <resource name="RAM" quantum="1M" />
!  <config ld_bind_now="yes" ld_verbose="no">
!  </config>
!</start>

Debugging dynamic binaries with GDB stubs
-----------------------------------------

! # go to directory containing the binaries
! cd <build/dir>/bin
!
! # start GDB with binary to debug
! gdb <binary name>
!
! # break in main routine
! b main
!
! # inspect loaded shared libraries
! info sharedlibrary
!
! # load shared symbols of shared libraries (if not already loaded)
! share
!
! # from here you can debug within libraries

:Known issues:

GDB 7.2 has a regression bug in its line information parser. These issue has
been fixed with version 7.3.