eglibc-nativesdk: Add patch to change the search path of the dynamic linker

Change the search path of the dynamic linker to search ld.so.cache as a last resort when
trying to find libraries at runtime. This means libs in /opt/poky are used in preference
but any host libs such as libGL can also be found. See the patch for a more detailed
description.

Signed-off-by: Richard Purdie <rpurdie@linux.intel.com>

2 files changed, 56 insertions, 1 deletions

diff --git a/meta/recipes-core/eglibc/eglibc-2.12/ld-search-order.patch b/meta/recipes-core/eglibc/eglibc-2.12/ld-search-order.patch
new file mode 100644
index 0000000000..e00f02a55c
--- /dev/null
+++ b/meta/recipes-core/eglibc/eglibc-2.12/ld-search-order.patch
@@ -0,0 +1,54 @@
+The default lib search path order is:
+
+  1) LD_LIBRARY_PATH
+  2) RPATH from the binary
+  3) ld.so.cache
+  4) default search paths embedded in the linker
+
+For nativesdk binaries which are being used alongside binaries on a host system, we 
+need the search paths to firstly search the shipped nativesdk libs but then also
+cover the host system. For example we want the host system's libGL and this may be
+in a non-standard location like /usr/lib/mesa. The only place the location is know 
+about is in the ld.so.cache of the host system.
+
+Since nativesdk has a simple structure and doesn't need to use a cache itself, we 
+repurpose the cache for use as a last resort in finding host system binaries. This 
+means we need to switch the order of 3 and 4 above to make this work effectively.
+
+RP 14/10/2010
+
+Index: libc/elf/dl-load.c
+===================================================================
+--- libc.orig/elf/dl-load.c     2010-10-14 11:34:54.944365484 +0100
++++ libc/elf/dl-load.c  2010-10-14 11:35:53.000000000 +0100
+@@ -2105,6 +2105,15 @@
+                        &loader->l_runpath_dirs, &realname, &fb, loader,
+                        LA_SER_RUNPATH, &found_other_class);
+ 
++      /* Try the default path.  */
++      if (fd == -1
++         && ((l = loader ?: GL(dl_ns)[nsid]._ns_loaded) == NULL
++             || __builtin_expect (!(l->l_flags_1 & DF_1_NODEFLIB), 1))
++         && rtld_search_dirs.dirs != (void *) -1)
++       fd = open_path (name, namelen, preloaded, &rtld_search_dirs,
++                       &realname, &fb, l, LA_SER_DEFAULT, &found_other_class);
++
++      /* Finally try ld.so.cache */
+       if (fd == -1
+          && (__builtin_expect (! preloaded, 1)
+              || ! INTUSE(__libc_enable_secure)))
+@@ -2167,14 +2176,6 @@
+            }
+        }
+ 
+-      /* Finally, try the default path.  */
+-      if (fd == -1
+-         && ((l = loader ?: GL(dl_ns)[nsid]._ns_loaded) == NULL
+-             || __builtin_expect (!(l->l_flags_1 & DF_1_NODEFLIB), 1))
+-         && rtld_search_dirs.dirs != (void *) -1)
+-       fd = open_path (name, namelen, preloaded, &rtld_search_dirs,
+-                       &realname, &fb, l, LA_SER_DEFAULT, &found_other_class);
+-
+       /* Add another newline when we are tracing the library loading.  */
+       if (__builtin_expect (GLRO_dl_debug_mask & DL_DEBUG_LIBS, 0))
+        _dl_debug_printf ("\n");
diff --git a/meta/recipes-core/eglibc/eglibc_2.12.bb b/meta/recipes-core/eglibc/eglibc_2.12.bb
index 999b0b07da..752c1d8cee 100644
--- a/meta/recipes-core/eglibc/eglibc_2.12.bb
+++ b/meta/recipes-core/eglibc/eglibc_2.12.bb
@@ -2,7 +2,7 @@ require eglibc.inc
 
 DEPENDS += "gperf-native"
 FILESPATHPKG =. "eglibc-svn:"
-PR = "r8"
+PR = "r9"
 
 EGLIBC_BRANCH="eglibc-2_12"
 SRC_URI = "svn://www.eglibc.org/svn/branches/;module=${EGLIBC_BRANCH};proto=http \
@@ -12,6 +12,7 @@ SRC_URI = "svn://www.eglibc.org/svn/branches/;module=${EGLIBC_BRANCH};proto=http
            file://mips-rld-map-check.patch \
            file://etc/ld.so.conf \
            file://generate-supported.mk"
+SRC_URI_append_virtclass-nativesdk = " file://ld-search-order.patch"
 S = "${WORKDIR}/${EGLIBC_BRANCH}/libc"
 B = "${WORKDIR}/build-${TARGET_SYS}"