ld.so: Replace DL_RO_DYN_SECTION with dl_relocate_ld [BZ #28340]

We can't relocate entries in dynamic section if it is readonly:

1. Add a l_ld_readonly field to struct link_map to indicate if dynamic
section is readonly and set it based on p_flags of PT_DYNAMIC segment.
2. Replace DL_RO_DYN_SECTION with dl_relocate_ld to decide if dynamic
section should be relocated.
3. Remove DL_RO_DYN_TEMP_CNT.
4. Don't use a static dynamic section to make readonly dynamic section
in vDSO writable.
5. Remove the temp argument from elf_get_dynamic_info.

This fixes BZ #28340.

Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>

1 files changed, 2 insertions, 5 deletions

diff --git a/sysdeps/generic/ldsodefs.h b/sysdeps/generic/ldsodefs.h
index 6e50fcd7cd..d49529da0d 100644
--- a/sysdeps/generic/ldsodefs.h
+++ b/sysdeps/generic/ldsodefs.h
@@ -75,11 +75,8 @@ __BEGIN_DECLS
   have to be accessed via the D_PTR macro.  The macro is needed since for
   most architectures the entry is already relocated - but for some not
   and we need to relocate at access time.  */
-#ifdef DL_RO_DYN_SECTION
-# define D_PTR(map, i) ((map)->i->d_un.d_ptr + (map)->l_addr)
-#else
-# define D_PTR(map, i) (map)->i->d_un.d_ptr
-#endif
+#define D_PTR(map, i) \
+  ((map)->i->d_un.d_ptr + (dl_relocate_ld (map) ? 0 : (map)->l_addr))
 
 /* Result of the lookup functions and how to retrieve the base address.  */
 typedef struct link_map *lookup_t;