eglibc: relocatable SDK changes

Modifying the dynamic loader path in all binaries by the SDK installer
would not be possible because we cannot know in advance the SDK target
location. Hence, the PT_INTERP section size has been set to 4096 (which
is the maximum path lengh in Linux).

Also, for the dynamic loader SYSDIRS and ld.so.cache paths, special
4096 bytes sections were allocated so that we can easily parse the ELF
binary at install time and modify the paths.

Signed-off-by: Laurentiu Palcu <laurentiu.palcu@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

1 files changed, 81 insertions, 0 deletions

diff --git a/meta/recipes-core/eglibc/eglibc-2.15/relocatable_sdk.patch b/meta/recipes-core/eglibc/eglibc-2.15/relocatable_sdk.patch
new file mode 100644
index 0000000000..0ee25d60d7
--- /dev/null
+++ b/meta/recipes-core/eglibc/eglibc-2.15/relocatable_sdk.patch
@@ -0,0 +1,81 @@
+Upstream-Status: Inappropriate [SDK specific]
+
+This patch puts the dynamic loader path in the binaries, SYSTEM_DIRS strings
+and lengths as well as ld.so.cache path in the dynamic loader to specific
+sections in memory. The sections that contain paths have been allocated a 4096
+byte section, which is the maximum path length in linux. This will allow the
+relocating script to parse the ELF binary, detect the section and easily replace
+the strings in a certain path.
+
+Signed-off-by: Laurentiu Palcu <laurentiu.palcu@intel.com>
+
+Index: libc/elf/interp.c
+===================================================================
+--- libc.orig/elf/interp.c
++++ libc/elf/interp.c
+@@ -17,5 +17,5 @@
+    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+    02111-1307 USA.  */
+ 
+-const char __invoke_dynamic_linker__[] __attribute__ ((section (".interp")))
++const char __invoke_dynamic_linker__[4096] __attribute__ ((section (".interp")))
+   = RUNTIME_LINKER;
+Index: libc/elf/dl-load.c
+===================================================================
+--- libc.orig/elf/dl-load.c
++++ libc/elf/dl-load.c
+@@ -145,8 +145,8 @@ static size_t max_capstrlen attribute_re
+ /* Get the generated information about the trusted directories.  */
+ #include "trusted-dirs.h"
+ 
+-static const char system_dirs[] = SYSTEM_DIRS;
+-static const size_t system_dirs_len[] =
++static const char system_dirs[4096] __attribute__ ((section (".sysdirs"))) = SYSTEM_DIRS;
++volatile static const size_t system_dirs_len[] __attribute__ ((section (".sysdirslen"))) =
+ {
+   SYSTEM_DIRS_LEN
+ };
+Index: libc/elf/dl-cache.c
+===================================================================
+--- libc.orig/elf/dl-cache.c
++++ libc/elf/dl-cache.c
+@@ -134,6 +134,10 @@ do									      \
+ while (0)
+ 
+ 
++const char LD_SO_CACHE[4096] __attribute__ ((section (".ldsocache"))) =
++		SYSCONFDIR "/ld.so.cache";
++
++
+ int
+ internal_function
+ _dl_cache_libcmp (const char *p1, const char *p2)
+Index: libc/elf/ldconfig.c
+===================================================================
+--- libc.orig/elf/ldconfig.c
++++ libc/elf/ldconfig.c
+@@ -167,6 +167,9 @@ static struct argp argp =
+   options, parse_opt, NULL, doc, NULL, more_help, NULL
+ };
+ 
++
++extern const char LD_SO_CACHE[4096] __attribute__ ((section (".ldsocache")));
++
+ /* Check if string corresponds to an important hardware capability or
+    a platform.  */
+ static int
+Index: libc/sysdeps/generic/dl-cache.h
+===================================================================
+--- libc.orig/sysdeps/generic/dl-cache.h
++++ libc/sysdeps/generic/dl-cache.h
+@@ -28,10 +28,6 @@
+   ((flags) == 1 || (flags) == _DL_CACHE_DEFAULT_ID)
+ #endif
+ 
+-#ifndef LD_SO_CACHE
+-# define LD_SO_CACHE SYSCONFDIR "/ld.so.cache"
+-#endif
+-
+ #ifndef add_system_dir
+ # define add_system_dir(dir) add_dir (dir)
+ #endif