[PATCH] Allow use of executable RPATH/RUNPATH when finding libraries.

[Steve Ellcey]

This option will modify ldso so that it will use the executables
RPATH/RUNPATH to find to find libraries even though this behavour
is not standard.  Setting this option causes the uclibc dynamic linker
behavour to match the glibc dynamic linker.

Signed-off-by: Steve Ellcey <sellcey at imgtec.com>
---
 extra/Configs/Config.in |    9 +++++++++
 ldso/ldso/dl-elf.c      |   12 ++++++++++++
 2 files changed, 21 insertions(+)

diff --git a/extra/Configs/Config.in b/extra/Configs/Config.in
index 8e603b2..a235c3d 100644
--- a/extra/Configs/Config.in
+++ b/extra/Configs/Config.in
@@ -418,6 +418,15 @@ config LDSO_RUNPATH
 	  Usage of RUNPATH tags is not too common, so disabling this feature
 	  should be safe for most people.
 
+config LDSO_RUNPATH_OF_EXECUTABLE
+	bool "Use executables RPATH/RUNPATH when searching for libraries."
+	depends on LDSO_RUNPATH
+	default n
+	help
+	  Use the executables RPATH/RUNPATH to find to find libraries even
+	  though this behavour is not standard.  Setting this option causes
+	  the uclibc dynamic linker behavour to match the glibc dynamic linker.
+
 config LDSO_SAFE_RUNPATH
 	bool "Allow only RUNPATH beginning with /"
 	depends on LDSO_RUNPATH
diff --git a/ldso/ldso/dl-elf.c b/ldso/ldso/dl-elf.c
index 54501d1..56076b6 100644
--- a/ldso/ldso/dl-elf.c
+++ b/ldso/ldso/dl-elf.c
@@ -237,6 +237,18 @@ struct elf_resolve *_dl_load_shared_library(unsigned rflags, struct dyn_elf **rp
 		if ((tpnt1 = search_for_named_library(libname, rflags, pnt, rpnt)) != NULL)
 			return tpnt1;
 	}
+#ifdef __LDSO_RUNPATH_OF_EXECUTABLE__
+        /*
+         * Try the DT_RPATH of the executable itself.
+         */
+        pnt = (char *) _dl_loaded_modules->dynamic_info[DT_RPATH];
+        if (pnt) {
+                pnt += (unsigned long) _dl_loaded_modules->dynamic_info[DT_STRTAB];
+                _dl_if_debug_dprint("\tsearching exe's RPATH='%s'\n", pnt);
+                if ((tpnt1 = search_for_named_library(libname, rflags, pnt, rpnt)) != NULL)
+                        return tpnt1;
+        }
+#endif
 #endif
 
 #ifdef __LDSO_LD_LIBRARY_PATH__
-- 
1.7.9.5