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, 33 insertions, 0 deletions

diff --git a/elf/tst-latepthreadmod.c b/elf/tst-latepthreadmod.c
new file mode 100644
index 0000000000..ce81206f2a
--- /dev/null
+++ b/elf/tst-latepthreadmod.c
@@ -0,0 +1,33 @@
+/* DSO which links against libpthread and triggers a lazy binding.
+   Copyright (C) 2016 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+/* This file is compiled into a DSO which loads libpthread, but fails
+   the dynamic linker afterwards.  */
+
+#include <pthread.h>
+
+/* Link in libpthread.  */
+void *pthread_create_ptr = &pthread_create;
+
+int this_function_is_not_defined (void);
+
+int
+trigger_dynlink_failure (void)
+{
+  return this_function_is_not_defined ();
+}