ldso: Add implementation of ld.so standalone execution

The dynamic linker can be run either indirectly through running some
dynamically linked program or library (in which case no command line options
to the dynamic linker can be passed and, in the ELF case, the dynamic linker
which is stored in the .interp section of the program is executed)
or directly by running:
 /lib/ld-uClibc.so.*  [OPTIONS] [PROGRAM [ARGUMENTS]]

Stand-alone execution is a prerequisite for adding prelink capabilities
to uClibc dynamic linker, as well useful for testing an updated version
of the dynamic linker without breaking the whole system.

Currently supported option:
  --library-path PATH   use given PATH instead of content of the environment
                        variable LD_LIBRARY_PATH

(Mandatory for prelinking)

Not supported options:
  --list                list all dependencies and how they are resolved
  --verify              verify that given object really is a dynamically linked
                        object we can handle
  --inhibit-rpath LIST  ignore RUNPATH and RPATH information in object names
                        in LIST

This feature can be enabled by setting LDSO_STANDALONE_SUPPORT=y

Signed-off-by: Filippo Arcidiacono <filippo.arcidiacono@st.com>
Signed-off-by: Carmelo Amoroso <carmelo.amoroso@st.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/ldso/include/dl-hash.h b/ldso/include/dl-hash.h
index 34333f40f..edef9d81b 100644
--- a/ldso/include/dl-hash.h
+++ b/ldso/include/dl-hash.h
@@ -60,6 +60,10 @@ struct elf_resolve {
 #endif
 
   ElfW(Addr) mapaddr;
+#ifdef __LDSO_STANDALONE_SUPPORT__
+  /* Store the entry point from the ELF header (e_entry) */
+  ElfW(Addr) l_entry;
+#endif
   enum {elf_lib, elf_executable,program_interpreter, loaded_file} libtype;
   struct dyn_elf * symbol_scope;
   unsigned short usage_count;