genode

History

Stefan Kalkowski ed52d5a211 Introduce 'spec' subdirectories to outline aspects Instead of holding SPEC-variable dependent files and directories inline within the repository structure, move them into 'spec' subdirectories at the corresponding levels, e.g.: repos/base/include/spec repos/base/mk/spec repos/base/lib/mk/spec repos/base/src/core/spec ... Moreover, this commit removes the 'platform' directories. That term was used in an overloaded sense. All SPEC-relative 'platform' directories are now named 'spec'. Other files, like for instance those related to the kernel/architecture specific startup library, where moved from 'platform' directories to explicit, more meaningful places like e.g.: 'src/lib/startup'. Fix #1673		2015-09-16 13:58:50 +02:00
..
include	Minor cleanup fixes	2015-08-21 11:00:59 +02:00
spec	Introduce 'spec' subdirectories to outline aspects	2015-09-16 13:58:50 +02:00
startup	base: Genode's dynamic linker	2014-11-12 14:44:15 +01:00
debug.cc	ldso: Refactor dynamic linker	2015-03-19 08:57:22 +01:00
dependency.cc	Minor cleanup fixes	2015-08-21 11:00:59 +02:00
exception.cc	ldso: Refactor dynamic linker	2015-03-19 08:57:22 +01:00
file.cc	Minor cleanup fixes	2015-08-21 11:00:59 +02:00
linker.ld	base: Genode's dynamic linker	2014-11-12 14:44:15 +01:00
main.cc	ldso: Refactor dynamic linker	2015-03-19 08:57:22 +01:00
README	base: Genode's dynamic linker	2014-11-12 14:44:15 +01:00
shared_object.cc	ldso: Refactor dynamic linker	2015-03-19 08:57:22 +01:00
symbol.map	ldso: add lx_environ to symbol map	2015-07-07 19:48:07 +02:00
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.