Implement _dl_catch_error, _dl_signal_error in libc.so [BZ #16628]

This change moves the main implementation of _dl_catch_error,
_dl_signal_error to libc.so, where TLS variables can be used
directly.  This removes a writable function pointer from the
rtld_global variable.

For use during initial relocation, minimal implementations of these
functions are provided in ld.so.  These are eventually interposed
by the libc.so implementations.  This is implemented by compiling
elf/dl-error-skeleton.c twice, via elf/dl-error.c and
elf/dl-error-minimal.c.

As a side effect of this change, the static version of dl-error.c
no longer includes support for the
_dl_signal_cerror/_dl_receive_error mechanism because it is only
used in ld.so.

1 files changed, 0 insertions, 19 deletions

diff --git a/elf/rtld.c b/elf/rtld.c
index 647661ca45..4ec25d7c30 100644
--- a/elf/rtld.c
+++ b/elf/rtld.c
@@ -167,8 +167,6 @@ struct rtld_global_ro _rtld_global_ro attribute_relro =
 
     /* Function pointers.  */
     ._dl_debug_printf = _dl_debug_printf,
-    ._dl_catch_error = _dl_catch_error,
-    ._dl_signal_error = _dl_signal_error,
     ._dl_mcount = _dl_mcount,
     ._dl_lookup_symbol_x = _dl_lookup_symbol_x,
     ._dl_check_caller = _dl_check_caller,
@@ -637,18 +635,6 @@ cannot allocate TLS data structures for initial thread");
   return tcbp;
 }
 
-#ifdef _LIBC_REENTRANT
-/* _dl_error_catch_tsd points to this for the single-threaded case.
-   It's reset by the thread library for multithreaded programs.  */
-void ** __attribute__ ((const))
-_dl_initial_error_catch_tsd (void)
-{
-  static void *data;
-  return &data;
-}
-#endif
-
-
 static unsigned int
 do_preload (const char *fname, struct link_map *main_map, const char *where)
 {
@@ -752,11 +738,6 @@ dl_main (const ElfW(Phdr) *phdr,
 #endif
   void *tcbp = NULL;
 
-#ifdef _LIBC_REENTRANT
-  /* Explicit initialization since the reloc would just be more work.  */
-  GL(dl_error_catch_tsd) = &_dl_initial_error_catch_tsd;
-#endif
-
   GL(dl_init_static_tls) = &_dl_nothread_init_static_tls;
 
 #if defined SHARED && defined _LIBC_REENTRANT \